fix: internal service accounts are the router's own, of which the metrics service's is the one at present, and the documentation says what a service account is.

fix: service accounts are managed at /service-accounts, not /users, and the internal one of the metrics service is only listed.
fix: vpn-router-setup owns only the creation of the metrics service's account, which is marked internal, and administrators add service accounts with vpn-router-user add --service and /users.
2026-10-25 18:27:10 +01:00 · 2026-10-25 18:18:03 +01:00 · 2026-10-25 18:00:25 +01:00 · 2026-10-25 17:32:48 +01:00 · 2026-10-25 17:14:23 +01:00 · 2026-10-25 15:26:54 +01:00
33 changed files with 2670 additions and 422 deletions
@@ -42,15 +42,22 @@ the package depends on, and no web framework. It listens on `web.port`, 7081 by
 address of the internal interface, of the external interface or of both, as `web.listen` sets
 (`internal`, `external` or `both`, the default), with a server for each address, and is on
 unless `web.enabled` is `false` (ADR-7). `/` is for people, in plain text for `curl` and `wget`
-and as a Tailwind CSS page for a browser, and `/status` is the same status as JSON. It shows the
-state of the services, the package version and the state of the site-to-site, road-warrior,
-OpenVPN and WireGuard features, and nothing from the configuration. `vpn-router-setup` opens the
+and as a Tailwind CSS page for a browser, and `/status` is the same status as JSON. Both show as
+much as `web.status_content` says, since the router is reachable from the internet and the
+operator decides how much it tells strangers: `basic`, the default because it tells the least,
+the overall status and the Client IP, `standard` also the package versions and the number of
+active and other services, and `full` also each service and the state of the site-to-site, road-warrior, OpenVPN and
+WireGuard features. The Client IP is the address the request came from, through the trusted
+proxies, so a person can see the address the router sees. Nothing comes from the configuration.
+`/status` names its content, so clients such as manage-ui and the Router Manager show what it
+has. `vpn-router-setup` opens the
 port on both interfaces in UFW, so the choice of `web.listen` is made by the service alone, and
 writes the features and the facts it resolves to `/run/vpn-router/web.json`.

 Consequences: By default the service is reachable from the internet on the external address;
-`web.listen` set to `internal` keeps it to the internal network. It serves plain HTTP, so the
-passwords of `/auth` and the tokens cross the internet unencrypted. A change of `web.listen`
+`web.listen` set to `internal` keeps it to the internal network. It serves plain HTTP itself;
+HTTPS is Caddy's (ADR-21), so on the plain HTTP port the passwords of `/auth` and the tokens
+cross the internet unencrypted. A change of `web.listen`
 needs no run of setup, since the firewall does not depend on it; the package's upgrade runs
 setup, which writes the rules. `/` and `/status` have no authentication, which is acceptable because they are
 read only and show no configuration. It runs as root, because `swanctl` and `wg` need it, with `NoNewPrivileges`,
@@ -192,10 +199,15 @@ that a secret is set tells a reader more than it needs.

 Decision: The configuration that `vpn-router-setup` writes for the web service has no secret
 options at all. They are recognised by name: `psk`, `database`, whose connection string may hold
-a password, and options with `secret`, `password`, `token` or a `_key` ending in the name.
+a password, and options with `secret`, `password`, `token` or a `_key` ending in the name. The
+names are checked at every level, so the settings of each site-to-site connection lose their
+`psk` too; an object is kept whatever its name, so a connection named like a secret is still
+shown.

-Consequences: No secret reaches the web service's state file or any answer of the API. A client
-cannot tell whether a secret is set. A new secret option needs a name that matches.
+Consequences: No secret reaches the web service's state file or any answer of the API. Through
+`/config` a client cannot tell whether a secret is set; `/site-to-site` says whether each
+connection has a key (ADR-25), as an admin managing connections needs to know. A new secret
+option needs a name that matches.

 ## ADR-9: The Router Manager is a separate package with a small Python server

@@ -460,8 +472,8 @@ e-mail address can be added later without changing their classes; VPN users get
 used.

 Consequences: The schema check stays strict. New attributes extend `vpnRouterAccount`, and their
-OIDs continue the arcs. Nothing reads `vpnRouterScope` yet. The OID must never be reused for
-anything else.
+OIDs continue the arcs. The scope `service` marks a service account (ADR-23). The OID must never
+be reused for anything else.

 ## ADR-20: Users manage their own account through /account, proving who they are again

@@ -486,3 +498,179 @@ Consequences: slapd's `otp` overlay accepts each code once, so a change right af
 needs the next code. Changing the password revokes the user's refresh tokens, so the user's
 Manager session ends with its access token. An enrolled user who has lost the authenticator
 needs an administrator.
+
+## ADR-21: Caddy from the Ubuntu archive serves HTTPS with a certificate from Let's Encrypt
+
+Status: Accepted
+
+Context: The status web service and the Router Manager are reachable from the internet (ADR-2),
+and `/auth` and the Manager's sign-in carry passwords. Both are small servers on the standard
+library's `http.server`, which would need certificates, their renewal and a TLS setup of their
+own. Browsers trust a public CA, not the router's.
+
+Decision: Caddy, the `caddy` package of the Ubuntu archive, is the HTTPS proxy. While
+`https.enabled` is `true` (the default) and `wan.local_fqdn` is set, `vpn-router-setup` writes
+`/etc/caddy/vpn-router.Caddyfile`: a site for `wan.local_fqdn` on `https.web_port` (7444) for the
+web service and, while the Router Manager is installed, one on `https.manager_port` (7443) for
+the manager, each passing calls to the service on `127.0.0.1`. Caddy obtains and renews the
+certificate from Let's Encrypt with the HTTP challenge on port 80, which the firewall opens on
+the external interface; `auto_https disable_redirects` keeps port 80 to the challenge. The
+package's drop-in for `caddy.service` points it at that file and keeps it from starting before
+the file exists, so `/etc/caddy/Caddyfile`, a configuration file of the `caddy` package, is left
+unchanged. Both services always listen on `127.0.0.1` as well as on the interfaces their
+`listen` settings name, and trust `X-Forwarded-For` from it, which Caddy sets from the peer and
+never takes from the client.
+
+Consequences: HTTPS needs `wan.local_fqdn` in public DNS pointing at the router and port 80
+reachable from the internet; until then Caddy retries and the HTTPS ports do not answer. The
+certificate and the ACME account are in `/var/lib/caddy`. Plain HTTP stays as the `listen`
+settings set it, so `internal` keeps passwords off the internet. Caddy's admin endpoint listens
+on `localhost:2019`, which `caddy reload` uses. Port 80 and the HTTPS ports are not available
+to Docker containers while HTTPS is on. The Manager's HTTPS port is a setting of the router, not
+of the manager.
+
+## ADR-22: Metrics are kept in PostgreSQL and served in the Prometheus format, pushed with OTLP
+
+Status: Accepted
+
+Context: The router should keep its CPU, memory, disk, network, load and VPN client metrics for
+hour, day, month and year views, as Proxmox VE does, and expose them to OpenTelemetry. Ubuntu
+noble has no OpenTelemetry Python SDK and no OpenTelemetry Collector package. OTLP itself is
+push-only; a collector reads a scraped endpoint in the Prometheus format with its `prometheus`
+receiver. The router already runs PostgreSQL for the refresh tokens (ADR-15).
+
+Decision: A service of its own, `vpn-router-metrics`, takes a sample every minute with `psutil`
+(`python3-psutil`) and the VPN readers it shares with the web service (`vpnrouter_status`). It
+keeps the samples in the router's database, in four detail tables (`metrics_system`,
+`metrics_network`, `metrics_vpn`, `metrics_site_to_site`, see ADR-25). Each detail table has hourly, daily, monthly and yearly summary
+tables, with the average and the maximum of each value per period, written when the clock passes a
+period from the level below with `INSERT ... ON CONFLICT DO NOTHING`, so a stopped service catches
+up. Garbage collection runs on start and once a day, not with every write, and deletes the rows
+older than the retention of their level, `metrics.keep_*`, PostgreSQL intervals. The service serves
+the last sample as `/metrics` in the Prometheus text format with `prometheus_client`
+(`python3-prometheus-client`) and pushes it as OTLP/HTTP JSON, built with the standard library, to
+`metrics.otlp_endpoint`. The names follow the OpenTelemetry semantic conventions. The web service
+answers the views from the tables at `/metrics/history`, protected like `/config`, for the Router
+Manager.
+
+Consequences: The metrics live in the database of the refresh tokens and are dropped with it on
+purge. A view shows only what its level keeps, so a shorter retention empties the older part of a
+view. A month view needs the hourly rows and a year view the monthly rows. `/metrics` has only the
+last sample; history is not scraped.
+
+## ADR-23: /metrics takes HTTP Basic authentication of an internal service account the router manages
+
+Status: Accepted
+
+Context: An OpenTelemetry Collector's `prometheus` receiver authenticates with HTTP Basic, not with
+the router's tokens, which last minutes (ADR-3). The scraper should not be able to sign in to the
+API or the Manager, and its password should be checked and locked out like any other. The account
+belongs to the package's metrics, not to the people using the router.
+
+Decision: A service account is a Manager-only account (ADR-18) with `vpnRouterScope` `service`,
+which another system signs in with to use a router service. Administrators add service accounts
+with `vpn-router-user add --service` and the web service's `/service-accounts`.
+`/service-accounts` is a path of its own, apart from `/users`, which does not list or serve them:
+a service account has no names, certificate, profile or TOTP, and is not a person an
+administrator manages with the users. Internal service accounts are those the router creates and
+manages for its own services (`vpnrouter_users.internal_accounts`), so the system, not an
+administrator, owns them; at present that is the metrics service's. `/service-accounts` marks
+them as `internal` and only lists them: every other request on one, and putting one in or taking
+one out of a group at `/groups`, gets 403, whatever the token. The router changes them through the
+directory's user-manager account, not the API, and root may still with `vpn-router-user`. For the
+metrics service, `vpn-router-setup` adds the account `metrics.service_account` names, `metrics` by
+default, while metrics are enabled, with a random password it writes to
+`/etc/vpn-router/metrics.secret` (root only), and sets a new random password, ending a lockout,
+when the file is missing or no longer holds the password. `/auth` refuses every service account with the message of a wrong password. `/metrics` accepts HTTP Basic only for that account, and
+only when it is a service account; the password is checked with a bind as the account, so the
+password policy's lockout applies (ADR-14). TLS is Caddy's, on `metrics.https_port` (ADR-21);
+plain HTTP is served on the interfaces `metrics.listen` names, `internal` by default.
+
+Consequences: Every scrape binds to slapd once. The collector's operator copies the password from
+the router; deleting the file and running setup changes it. A user who already has the name is not
+taken over; setup fails until `metrics.service_account` names another. An account root disabled
+stays disabled. A scraper on the external interface over plain HTTP sends the password in the clear, so
+`metrics.listen` stays `internal` unless HTTPS is used.
+
+## ADR-24: The Router Manager upgrades the router's packages in a transient unit outside its own
+
+Status: Accepted
+
+Context: An admin should upgrade `vpn-router` and `vpn-router-manager` from the Router Manager. The
+upgrade restarts the process that starts it: the manager's postinst restarts
+`vpn-router-manager.service`, and the router's restarts `vpn-router-web` and `vpn-router-setup`. A
+child of the manager would be stopped with the manager's cgroup in the middle of dpkg, leaving
+packages half configured, and the manager's unit cannot run apt at all, since `ProtectSystem=strict`
+makes `/usr` and `/var/lib/dpkg` read-only. The package lists are updated by a cron job, not by the
+manager.
+
+Decision: The manager starts the helper `/usr/lib/vpn-router-manager/upgrade` with `systemd-run` as
+the transient unit `vpn-router-manager-upgrade`, of its own cgroup and without a sandbox, and does
+not wait for it. The helper:
+
+- finishes an interrupted dpkg run with `dpkg --configure -a`;
+- runs `apt-get install --only-upgrade` of the two packages, non-interactive, keeping changed configuration files, with `needrestart` suspended, and waiting for the dpkg lock that the cron job may hold;
+- records the state and the result in `/var/lib/vpn-router-manager/upgrade.json`, replaced by a rename, and the output in `upgrade.log`.
+
+A restarted manager reads them again. A state of running without an active unit is shown as interrupted. The manager reboots the router the same way, as a transient timer `vpn-router-manager-reboot` 5 seconds later, so the answer reaches the browser first. Only members of `admins`, as the router's `/account` answers, may start either.
+
+Consequences: The fixed unit name allows one upgrade at a time. The page loses the manager and the
+router's web service for a while during an upgrade and reads again until they answer. Sessions
+survive in PostgreSQL. The manager can upgrade only the system it runs on, so a manager on another
+host upgrades that host's packages, not the router's. The operating system's other packages are
+left to unattended-upgrades.
+
+## ADR-25: Site-to-site connections are a map of named connections, edited through the API and applied by setup
+
+Status: Accepted
+
+Context: The router had one IPsec site-to-site tunnel, the `remote` section, run as the swanctl
+connection `remote-site`, with the local identity mode in `wan` and the local subnets in `local`.
+A router often links more than one site, each with its own peer, subnets and key, and an admin
+should add them without a shell. The install answers and the Cloud Platform describe one
+connection, and the platform rewrites `vpn-router.json` when it rebuilds the VM.
+
+Decision: `site_to_site` maps a connection name to its settings: `addrs`, `id`, `cidrs`,
+`local_cidrs`, `local_id_mode`, `psk` and `psk_file`. `remote` and `wan.local_id_mode` are gone,
+without a fallback for the old format. The name, a lowercase letter followed by at most 30
+lowercase letters, digits and hyphens, names the swanctl connection, its child and its secret
+`ike-psk-<name>`, so it is a valid swanctl section name and stays the same while the connection
+lives. The install answers and the Cloud Platform write the connection `remote-site`, the first
+one, so its name is the one the tunnel always had.
+
+- **Local settings per connection:** each connection has its own `local_cidrs` and
+  `local_id_mode`, as each peer expects its own traffic selectors and identity. `wan.local_fqdn`
+  stays the router's one name, used by the `fqdn` mode, resolved once for the `public_ip` mode,
+  and used by HTTPS, road-warrior and OpenVPN. `local.cidrs` stays the subnets the router
+  routes, masquerades and offers to road-warrior and OpenVPN clients.
+- **One file:** `vpn-router-setup` writes every connection that is ready to
+  `/etc/swanctl/conf.d/site-to-site.conf`, with the proposals and timers the one tunnel had, and
+  removes the file when none is. The NAT exemptions pair each connection's `local_cidrs` with its
+  `cidrs`.
+- **Editing:** the status web service serves `/site-to-site` to members of `admins` and admin
+  tokens, like `/users`. It never returns a key, only whether one is set, and takes a new key only
+  when one is given. `vpn-config-edit` edits the same map. Both read, check with the validation
+  of `vpn-router-setup` and write `vpn-router.json` holding one lock, replacing the file in one
+  step, so neither loses the other's change.
+- **Applying:** the web service restarts `vpn-router-setup` without waiting for it, the one
+  place that renders, loads and opens the firewall, so a change through the API takes the same
+  path as a change by hand.
+- **Metrics per connection:** the metrics service keeps, per connection, whether it is up, the
+  bytes and packets per second through its child SAs and the seconds its IKE SA has been up, in
+  a detail table of its own, `metrics_site_to_site`, keyed by the connection's name, with the
+  summaries and retention of the other tables (ADR-22). One row per connection keeps the values
+  of a tunnel together and lets the set of connections change without changing the schema;
+  `metrics_vpn` counts only clients. swanctl's child SA counters start again at a rekey, so the
+  service keeps rates computed between two samples, treating a lower counter as counted from
+  zero, and `/metrics` and the OTLP push serve them as gauges rather than counters that would
+  appear to reset.
+
+Consequences: A configuration with `remote` is refused, so the package and a configuration in
+the new format go together. The status shows each connection. A rate across a rekey misses the
+traffic of the old child SA since the previous sample. A renamed connection starts a new series.
+A connection added through the API lives in
+`vpn-router.json` only; the Cloud Platform's rebuild of the VM writes the file again with its
+one connection, dropping the others. A change through the API is answered before setup has
+applied it, so a configuration that setup cannot apply shows in the setup state, not in the
+answer. A connection with a key file keeps it until a key is given through the API, which then
+replaces the file.
@@ -9,6 +9,8 @@ A Debian package that configures a Linux host or virtual machine as a VPN router
 - optional WireGuard endpoint
 - routing and NAT for a protected subnet, TCP MSS clamping, and UFW firewall rules
 - firewall rules for the ports Docker publishes, when Docker is installed
+- metrics of the router kept in PostgreSQL, served for an OpenTelemetry Collector and pushed
+  over OTLP

 Nothing in the package is specific to a cloud provider. It is built on the external and
 internal NIC names, and a `mode` setting says how much of the rest you are supplying and
@@ -101,16 +103,11 @@ must have the type shown below; an unknown section or setting is an error.
 | `general` | `mode` | string | `manual` | How much you supply: `manual`, `interfaces` or `auto` |
 | `interfaces` | `external` | string | | Name of the NIC facing the untrusted network |
 | `interfaces` | `internal` | string | | Name of the NIC facing the protected network |
-| `wan` | `local_fqdn` | string | | This router's name or IP address, used as its IKE identity in `fqdn` mode |
-| `wan` | `local_id_mode` | string | `fqdn` | IKE identity source: `fqdn`, `public_ip` or `internal_ip` |
-| `local` | `cidrs` | list | | Local subnets advertised into the tunnel |
+| `wan` | `local_fqdn` | string | | This router's name or IP address: its IKE identity in `fqdn` mode, the name resolved in `public_ip` mode, and the name of HTTPS, road-warrior and OpenVPN |
+| `local` | `cidrs` | list | | Local subnets routed via the internal side, masqueraded to the external one, and offered to road-warrior and OpenVPN clients |
 | `local` | `int_addr` | string | | This host's address on the internal network |
 | `local` | `int_gateway_ip` | string | | Next hop on the internal side |
-| `remote` | `addrs` | list | | Remote gateway addresses or FQDNs |
-| `remote` | `id` | string | | Remote IKE identity, an FQDN or an IPv4 or IPv6 address |
-| `remote` | `cidrs` | list | | Remote subnets reachable through the tunnel |
-| `remote` | `psk` | string | | Pre-shared key |
-| `remote` | `psk_file` | string | | Path to a file holding the key; wins over `psk` |
+| `site_to_site` | | object | | The site-to-site connections, each a name and an object of the settings below |
 | `p2s` | `enabled` | boolean | `false` | Road-warrior access |
 | `p2s` | `address_pool` | string | | CIDR assigned to road-warrior clients |
 | `p2s` | `ca_name` | string | `VPN Router CA` | Common name for a locally created CA |
@@ -127,7 +124,48 @@ must have the type shown below; an unknown section or setting is an error.
 | `web` | `listen` | string | `both` | The interfaces the status web service listens on: `internal`, `external` or `both` |
 | `web` | `port` | integer | `7081` | TCP port of the status web service |
 | `web` | `database` | string | | A PostgreSQL connection string for the refresh tokens; without it, the `vpn-router` database on this host that the web service creates |
-| `web` | `trusted_proxies` | list | the address the call came in on | Addresses whose `X-Forwarded-For` header names the client for the `/auth` rate limit |
+| `web` | `trusted_proxies` | list | the address the call came in on | Addresses whose `X-Forwarded-For` header names the client for the `/auth` rate limit and the Client IP of the status |
+| `web` | `status_content` | string | `basic` | What `/` and `/status` show: `basic`, `standard` or `full` (see Status web service) |
+| `https` | `enabled` | boolean | `true` | Caddy serves the status web service and the Router Manager over HTTPS for `wan.local_fqdn` |
+| `https` | `email` | string | | The e-mail address of the Let's Encrypt account |
+| `https` | `web_port` | integer | `7444` | HTTPS port of the status web service |
+| `https` | `manager_port` | integer | `7443` | HTTPS port of the Router Manager |
+| `metrics` | `enabled` | boolean | `true` | The metrics service: collection, history and `/metrics` |
+| `metrics` | `listen` | string | `internal` | The interfaces `/metrics` is served on: `internal`, `external` or `both` |
+| `metrics` | `port` | integer | `9464` | TCP port of `/metrics` |
+| `metrics` | `https_port` | integer | `9465` | HTTPS port of `/metrics`, served by Caddy while `https.enabled` is true |
+| `metrics` | `service_account` | string | `metrics` | The service account `/metrics` takes, which `vpn-router-setup` adds and keeps |
+| `metrics` | `otlp_endpoint` | string | | An OTLP/HTTP URL the metrics are pushed to every minute, for example `https://collector.example.com:4318/v1/metrics` |
+| `metrics` | `otlp_username` | string | | The user name of HTTP Basic authentication at the OTLP endpoint |
+| `metrics` | `otlp_password` | string | | Its password |
+| `metrics` | `keep_details` | string | `24 hours` | How long the per-minute metrics are kept |
+| `metrics` | `keep_hourly` | string | `1 month` | How long the hourly summaries are kept |
+| `metrics` | `keep_daily` | string | `3 months` | How long the daily summaries are kept |
+| `metrics` | `keep_monthly` | string | `1 year` | How long the monthly summaries are kept |
+| `metrics` | `keep_yearly` | string | `10 years` | How long the yearly summaries are kept |
+
+### Site-to-site connections
+
+`site_to_site` maps a connection name to its settings. A name starts with a lowercase letter
+and has at most 31 lowercase letters, digits and hyphens; it names the strongSwan connection,
+its child and its secret (`ike-psk-<name>`). The install answers fill the connection
+`remote-site`; more are added in the file, with `vpn-config-edit`, or through `/site-to-site`
+of the status web service, which the Router Manager uses.
+
+| Setting | Type | Default | Meaning |
+|---|---|---|---|
+| `addrs` | list | | Remote gateway addresses or FQDNs |
+| `id` | string | | Remote IKE identity, an FQDN or an IPv4 or IPv6 address |
+| `cidrs` | list | | Remote subnets reachable through the tunnel |
+| `local_cidrs` | list | | Local subnets advertised into the tunnel |
+| `local_id_mode` | string | `fqdn` | The router's IKE identity: `fqdn` is `wan.local_fqdn`, `public_ip` the address it resolves to, `internal_ip` the internal address |
+| `psk` | string | | Pre-shared key |
+| `psk_file` | string | | Path to a file holding the key; wins over `psk` |
+
+A connection is set up once all of `addrs`, `id`, `cidrs`, `local_cidrs`, the key and its
+local identity are known; all such connections are written to
+`/etc/swanctl/conf.d/site-to-site.conf`. Traffic from a connection's `local_cidrs` to its
+`cidrs` is not masqueraded.

 A minimal site-to-site configuration in `auto` mode:

@@ -136,16 +174,19 @@ A minimal site-to-site configuration in `auto` mode:
  "general": { "platform": "generic", "mode": "auto" },
  "wan": { "local_fqdn": "router.example.com" },
  "local": { "cidrs": ["10.0.0.0/24"] },
-  "remote": {
-    "addrs": ["peer.example.net"],
-    "id": "peer.example.net",
-    "cidrs": ["192.168.0.0/24"],
-    "psk": "s3cr3t"
+  "site_to_site": {
+    "remote-site": {
+      "addrs": ["peer.example.net"],
+      "id": "peer.example.net",
+      "cidrs": ["192.168.0.0/24"],
+      "local_cidrs": ["10.0.0.0/24"],
+      "psk": "s3cr3t"
+    }
  }
 }
 ```

-The router's IKE identity (`wan.local_fqdn` in `fqdn` mode) and the remote one (`remote.id`) are
+The router's IKE identity (`wan.local_fqdn` in `fqdn` mode) and the remote one (`id`) are
 an FQDN or an IPv4 or IPv6 address. They are written to the strongSwan configuration as given;
 strongSwan reads an address as an IP identity and a name as an FQDN, so a leading `@` is not needed
 and is refused. Road-warrior and OpenVPN access need a name in `wan.local_fqdn`.
@@ -235,6 +276,29 @@ vpn-router-setup` applies a changed configuration while Docker runs. With `docke
 `on`, the service fails when Docker is not installed or its daemon is not running; with
 `off` it removes the rules.

+## Editing the configuration
+
+`vpn-config-edit`, run as root, shows and changes `/etc/vpn-router/vpn-router.json`:
+
+```sh
+vpn-config-edit show
+vpn-config-edit set web.status_content standard
+vpn-config-edit set web.port 7082
+vpn-config-edit set web.trusted_proxies 127.0.0.1,10.0.0.4
+vpn-config-edit set site_to_site.branch.addrs branch.example.net
+vpn-config-edit remove site_to_site.branch
+```
+
+`show` prints the file as indented JSON and does not change it. `set` takes a setting as
+`section.option`, or as `site_to_site.NAME.option` for a site-to-site connection, which it
+creates with the defaults when it does not exist, and converts the value to the setting's type:
+a whole number, `true` or `false`, a list separated by commas (an empty value is an empty list),
+or a string; an unknown setting is refused. `remove site_to_site.NAME` removes a connection. It
+checks the whole configuration as `vpn-router-setup` does, and only then writes the file,
+indented, with mode 0600, and reminds that `vpn-router-setup` applies it. The status web service
+writes the file the same way, and a lock keeps the two from overwriting each other's change. A
+refused request exits with status 2, any other failure with 1.
+
 ## Applying changes

 ```sh
@@ -329,8 +393,9 @@ is switched on:
  `account` for a Manager-only account (see Managing users);
 - the package's own schema, `cn=vpn-router,cn=schema,cn=config`, under the OID
  `2.25.98477352595735834532404256531620013001` of the UUID arc: the auxiliary class
-  `vpnRouterAccount` with `MAY ( mail $ vpnRouterScope )`, which Manager-only accounts have, and
-  the attribute `vpnRouterScope`, authorization scopes that nothing reads yet;
+  `vpnRouterAccount` with `MAY ( mail $ vpnRouterScope )`, which Manager-only and service accounts
+  have, and the attribute `vpnRouterScope`, authorization scopes, of which `service` marks a
+  service account;
 - `ou=groups` holds one `groupOfNames` per group, named by `cn`, with its members' DNs in
  `member` and an optional `description`;
 - `cn=user-manager,ou=services` is the account that changes users and groups; it may write
@@ -352,8 +417,8 @@ The directory is kept on purge.

 ### Managing users

-`vpn-router-user` manages the users. A user is a directory entry of one of two kinds, fixed when it
-is added:
+`vpn-router-user` manages the users. A user is a directory entry of one of three kinds, fixed when
+it is added:

 - a VPN user, an `inetOrgPerson` with a first name, a last name and an e-mail address
  (`givenName`, `sn` and `mail`; `cn` is the first and the last name), and a client certificate
@@ -361,7 +426,15 @@ is added:
 - a Manager-only account, an `account`, `simpleSecurityObject` and `vpnRouterAccount` with the
  name, the password and an optional e-mail address, for notifications: no names and no
  certificate, so no VPN access. It can sign in to `/auth` and, as a member of `admins`, manage
-  the router. `add` without the first and the last name adds one; its names cannot be set later.
+  the router. `add` without the first and the last name adds one; its names cannot be set later;
+- a service account, a Manager-only account whose `vpnRouterScope` is `service`, which another
+  system signs in with to use a router service, such as an OpenTelemetry Collector reading
+  `/metrics`; it cannot sign in to `/auth`. `add --service` adds one, and the web service manages
+  them at `/service-accounts`, not at `/users`. Internal service accounts are those the router
+  creates and manages for its own services; at present that is the metrics service's, the account
+  `metrics.service_account` names while metrics are enabled (see Metrics). The API only lists
+  them: `/service-accounts` refuses every other request on one, and `/groups` refuses to put one
+  in or take one out of a group, with 403.

 Passwords and TOTP secrets are read from the first line of standard input. The answer is text: a
 table of the users, the client profile, a TOTP secret or a short message, and a failure is a
@@ -373,6 +446,7 @@ after a command its options.
 ```sh
 echo 's3cr3t-pass' | vpn-router-user add alice --first-name Alice --last-name Smith --email alice@example.com
 echo 'm4nager-pass' | vpn-router-user add ops
+echo 's3rvice-pass' | vpn-router-user add backup --service
 vpn-router-user update alice --email a.smith@example.com
 vpn-router-user list
 vpn-router-user profile alice > alice.ovpn
@@ -392,6 +466,7 @@ vpn-router-user otp-remove alice
 | `list` | The users with their kind, names and e-mail addresses, whether each is enabled or locked, has a certificate and is enrolled for TOTP |
 | `add <name> --first-name F --last-name L --email E` | Adds a VPN user and issues the certificate |
 | `add <name> [--email E]` | Adds a Manager-only account, with the e-mail address when given; one name without the other two options is refused |
+| `add <name> --service [--email E]` | Adds a service account, with the e-mail address when given; the names are refused |
 | `update <name> [--first-name F] [--last-name L] [--email E]` | Changes the names or the e-mail address |
 | `passwd <name>` | Sets the password |
 | `disable <name>`, `enable <name>` | Locks the user out of OpenVPN and `/auth`, and lets the user in again |
@@ -406,8 +481,8 @@ A user name is 1 to 32 lowercase letters, digits and hyphens, starting with a le
 password has 8 to 128 characters; a first or last name has 1 to 64 printable characters; an
 e-mail address has one `@`, no spaces and a dot in its domain; a TOTP secret is 32 base32
 characters, as `otp-new` makes it, and a code 6 digits. Once enrolled, a user logs in to OpenVPN
-and `/auth` with the password followed by a current code. In the answers `manager_only` tells the
-kind, and a Manager-only account has its names as `null`; `update` changes only its e-mail
+and `/auth` with the password followed by a current code. In the answers `manager_only`, `service`
+and `internal` tell the kind, and a Manager-only account has its names as `null`; `update` changes only its e-mail
 address, and `--email ''` removes it. Changing a user's password, disabling, unlocking or removing the user also revokes its
 refresh tokens of `/auth`. The exit status is 0 on success, 2 for an invalid request, 3 when the
 user does not exist, 4 when the user exists and 1 for any other failure.
@@ -494,9 +569,21 @@ modules shipped with the package; the configuration file accepts any module inst
 ## Status web service

 The `vpn-router-web` service shows the state of the router on the addresses of the interfaces
-`web.listen` names, the internal, the external or both (the default), and `web.port` (7081 by
-default). Its pages `/` and `/status` need no authentication and show no
-configuration: no key, identity, address or subnet.
+`web.listen` names, the internal, the external or both (the default), and on `127.0.0.1`, where
+Caddy calls it (see HTTPS), with `web.port` (7081 by default). Its pages `/` and `/status` need no authentication and show no
+configuration: no key, identity, subnet, or address but the client's. They show as much as
+`web.status_content` says, read at each request:
+
+| `status_content` | `/` and `/status` show |
+|---|---|
+| `basic` (default) | The overall status (`ok` or `degraded`), the time and the Client IP |
+| `standard` | Also the `vpn-router` version, the `vpn-router-manager` version or that it is not installed, and the number of active services and of services in any other state, without their names |
+| `full` | Also each service and its state, Docker, and the state of each site-to-site connection, road-warrior, OpenVPN and WireGuard |
+
+The Client IP is the address the request came from: the last entry of `X-Forwarded-For` for a
+request from one of `web.trusted_proxies`, by default the address the request came in on, so
+behind Caddy or a Router Manager on the router it is the browser's. `/status` names the content in
+`content` and the Client IP in `client_ip`; `/` keeps the time and the link to `/status`.

 The service first makes its signing key and the refresh tokens' database, retrying every 15
 seconds, for example while PostgreSQL is not running yet, and logs each failure; then it listens.
@@ -526,7 +613,9 @@ curl http://10.0.0.4:17081/
 | `/auth` | Signing in with a user's password and TOTP code, refreshing and signing out |
 | `/config` | The configuration without its secret options, and what the router resolved and runs, as JSON; needs a token |
 | `/users` | The users of OpenVPN and road-warrior access; needs a token |
+| `/service-accounts` | The service accounts; needs a token |
 | `/groups` | The groups of users; needs a token |
+| `/site-to-site` | The site-to-site connections: list, add, change and remove; needs a token |
 | `/account` | The account of the signed-in user: its details, its password and its TOTP enrolment; needs a user's token |

 The status holds the state of `vpn-router-setup`, `slapd` and each PostgreSQL cluster unit
@@ -537,8 +626,8 @@ road-warrior access is configured, of `wg-quick@wg0` when WireGuard is, and of
 OpenVPN clients, from the server's status file, which OpenVPN rewrites every minute; the package version and,
 as `manager_version`, the installed version of `vpn-router-manager` (`null`, shown as not installed, without it); whether
 Docker is installed, and when it is, the state of `docker.service` and of `vpn-router-docker`
-(the Docker rules), which do not change `status`; whether the
-site-to-site tunnel is established; the number of connected road-warrior (IPsec P2S) clients; and
+(the Docker rules), which do not change `status`; as `site_to_site.connections`, whether each
+site-to-site connection that is set up is established (`null` when swanctl cannot be asked); the number of connected road-warrior (IPsec P2S) clients; and
 the WireGuard peers with the age of their last handshake and their traffic. `status` is `ok` when
 all these services are active, and `degraded` otherwise.

@@ -549,7 +638,7 @@ curl http://10.0.0.4:7081/status

 ### Tokens and signing in

-`/config`, `/users`, `/groups` and `/account` need a JWT in an `Authorization: Bearer` header, signed with
+`/config`, `/users`, `/service-accounts`, `/groups`, `/site-to-site` and `/account` need a JWT in an `Authorization: Bearer` header, signed with
 HS256 by the key the web service makes on its first run, `/etc/vpn-router/web.key` (root only).
 The key never leaves the router; while it does not exist these paths and `/auth` are not served
 (404). A missing, expired or wrongly signed token, or one of another algorithm, gets 401 with
@@ -607,11 +696,21 @@ curl -H "Authorization: Bearer $TOKEN" http://10.0.0.4:7081/config

 | Key | Content |
 | --- | --- |
-| `configuration` | `vpn-router.json` with the defaults applied, without its secret options (`psk`, `database`, and any option named like a secret, password, token or key) |
-| `network` | The external and internal interface, their addresses, the internal gateway, the local and remote IKE identities and subnets, and the IPv4 routes as `ip -j -4 route` prints them |
+| `configuration` | `vpn-router.json` with the defaults applied, without its secret options at any level (`psk`, `database`, and any option named like a secret, password, token or key) |
+| `network` | The external and internal interface, their addresses, the internal gateway, `local.cidrs`, `site_to_site`: each connection with `name`, `local_identity`, `remote_identity`, `local_cidrs` and `remote_cidrs`, and the IPv4 routes as `ip -j -4 route` prints them |
 | `ipsec` | `connections` and `sas`: one object per connection and per IKE SA, read from `swanctl --list-conns --pretty` and `swanctl --list-sas --pretty`, with the connection's name under `name` and swanctl's keys and string values |
 | `wireguard` | The public key and port of `wg0`, and each peer's public key, endpoint, allowed IPs, handshake age and traffic; no private or preshared key |
 | `docker` | `docker.exposed_ports` and the rules of the `VPN-ROUTER-DOCKER` chain |
+| `postgresql` | `clusters`: each PostgreSQL cluster of `pg_lsclusters` with its version, name, port, status and data directory, and for one that is online its `settings`: `server_version`, `listen_addresses`, `port`, `max_connections`, `shared_buffers`, `effective_cache_size`, `work_mem`, `password_encryption`, `ssl` and `timezone`; `null` when `pg_lsclusters` fails |
+
+### The /postgresql page
+
+`/postgresql`, with the same token as `/config`, shows the databases of the PostgreSQL clusters on the
+router:
+
+- **Content:** `clusters` lists each cluster with its version, name, port and status, its `databases` (name, owner, encoding and size in bytes, `pg_database_size`) and their total `size`.
+- **A cluster that is not online:** `databases` and `size` are `null`.
+- **Collection:** the web service reads it with `psql` as the `postgres` user at each request.

 ### The /users API

@@ -621,7 +720,7 @@ and answer bodies are JSON; a request body is at most 4096 bytes.

 | Request | Body | Answer |
 | --- | --- | --- |
-| `GET /users` | | `{"users": [{"name", "manager_only", "enabled", "locked", "certificate", "otp", "first_name", "last_name", "email"}, ...]}` |
+| `GET /users` | | `{"users": [{"name", "manager_only", "service", "internal", "enabled", "locked", "certificate", "otp", "first_name", "last_name", "email"}, ...]}` |
 | `POST /users` | `{"name", "password", "first_name", "last_name", "email"}` for a VPN user; `{"name", "password", "email"?}` for a Manager-only account | 201 and the user |
 | `PUT /users/<name>` | any of `{"first_name", "last_name", "email"}`; for a Manager-only account only `{"email"}`, `""` removing it | the user |
 | `PUT /users/<name>/password` | `{"password": ...}` | the user |
@@ -635,7 +734,8 @@ and answer bodies are JSON; a request body is at most 4096 bytes.
 | `DELETE /users/<name>/otp` | | the user |

 A failure is `{"error": ...}` with 400 for an invalid request, 404 for a user that does not
-exist, 409 for a user that exists and 500 otherwise. `/users` works whether or not OpenVPN or
+exist or is a service account, 409 for a user that exists and 500 otherwise. `/users` does not
+list service accounts; `/service-accounts` serves them. `/users` works whether or not OpenVPN or
 road-warrior access is enabled; the profile needs OpenVPN. Passwords, private keys and TOTP
 secrets cross the internal network in plain HTTP, like the token.

@@ -645,6 +745,26 @@ curl -H "Authorization: Bearer $TOKEN" -H 'Content-Type: application/json' \
     http://10.0.0.4:7081/users
 ```

+### The /service-accounts API
+
+`/service-accounts` manages the service accounts with the same token and the same module as
+`/users`.
+
+| Request | Body | Answer |
+| --- | --- | --- |
+| `GET /service-accounts` | | `{"service_accounts": [{"name", "internal", "enabled", "locked", "email", ...}, ...]}`, each as `/users` shows a user |
+| `POST /service-accounts` | `{"name", "password", "email"?}` | 201 and the account |
+| `PUT /service-accounts/<name>` | `{"email"}`; `""` removes it | the account |
+| `PUT /service-accounts/<name>/password` | `{"password": ...}` | the account |
+| `POST /service-accounts/<name>/disable` | | the account |
+| `POST /service-accounts/<name>/enable` | | the account |
+| `POST /service-accounts/<name>/unlock` | | the account |
+| `DELETE /service-accounts/<name>` | | `{"name", "removed": true}` |
+
+The internal service accounts, `internal` true, are only listed: every other request on one gets
+403, as the router manages them. A failure is otherwise as for `/users`, with 404 also for a
+name that is not a service account.
+
 ### The /account API

 `/account` serves the user the access token names, whether or not the user is a member of
@@ -681,6 +801,26 @@ member, 404 for a group or user that does not exist, 409 for a group that exists
 otherwise. `DELETE /users/<name>` is refused with 400 while the user is the last member of a
 group.

+### The /site-to-site API
+
+`/site-to-site` manages the site-to-site connections of `vpn-router.json` with the same token as
+`/users`.
+
+| Request | Body | Answer |
+| --- | --- | --- |
+| `GET /site-to-site` | | `{"connections": [{"name", "addrs", "id", "cidrs", "local_cidrs", "local_id_mode", "psk_file", "psk_set", "established"}, ...]}` |
+| `POST /site-to-site` | `{"name", "addrs", "id", "cidrs", "local_cidrs", "local_id_mode", "psk"}`; `psk` is required | 201 and the connection |
+| `PUT /site-to-site/<name>` | any of the settings of `POST` but `name`; an empty or absent `psk` keeps the key, a `psk` given replaces `psk_file` | the connection |
+| `DELETE /site-to-site/<name>` | | `{"name", "removed": true}` |
+
+A connection is shown without its key: `psk_set` says whether `psk` holds one, and `established`
+whether its tunnel is up, `null` when swanctl cannot be asked. Each change is made under the lock
+`vpn-config-edit` takes, checked as `vpn-router-setup` checks the configuration, written to
+`vpn-router.json`, and applied by restarting `vpn-router-setup` without waiting for it. A failure
+is `{"error": ...}` with 400 for an invalid request or configuration, with the reason, 404 for a
+connection that does not exist, 409 for a name that exists and 500 otherwise. Keys cross the
+internal network in plain HTTP, like the token.
+
 The service starts on its own, without waiting for `vpn-router-setup`, and keeps running. Every
 30 seconds it reads `web.listen`, `web.port` and `web.enabled` from `vpn-router.json` and works
 out the addresses of the interfaces `web.listen` names as `general.mode` directs; it listens on
@@ -691,28 +831,152 @@ and the facts for `/config` from `/run/vpn-router/web.json` (readable by root on
 `vpn-router-setup` writes; before that file exists the page shows no features.
 `vpn-router-setup` opens `web.port` on the internal and the external interface in the firewall.

+## HTTPS
+
+Caddy, from Ubuntu's `caddy` package, serves the status web service on `https.web_port` (7444 by
+default), while the Router Manager is installed the manager on `https.manager_port` (7443), and
+while metrics are enabled the metrics service on `metrics.https_port` (9465), all for `wan.local_fqdn`, while `https.enabled` is `true` and `wan.local_fqdn` is set. It obtains
+and renews the certificate from Let's Encrypt with the HTTP challenge, so `wan.local_fqdn` must
+resolve to the router's public address and port 80 must be reachable from the internet; the
+certificate and the ACME account are kept in `/var/lib/caddy`. Port 80 answers the challenge only;
+it does not redirect to HTTPS.
+
+`vpn-router-setup` writes Caddy's configuration to `/etc/caddy/vpn-router.Caddyfile` (root, group
+`caddy`, the group Caddy runs as, mode 0640), which the
+package's drop-in `/usr/lib/systemd/system/caddy.service.d/vpn-router.conf` makes `caddy.service`
+read; `caddy.service` does not start before the file exists, and `/etc/caddy/Caddyfile` is not
+used. Setup starts Caddy, reloads it when the file changes, and stops it and removes the file when
+HTTPS is off. In the firewall it opens port 80 on the external interface and the HTTPS ports on the
+internal and the external interface. Caddy calls both services on `127.0.0.1`, where they listen
+whatever `web.listen` and the manager's `listen` say, and passes the client's address in
+`X-Forwarded-For`, which the manager trusts from `127.0.0.1` and the web service by default, as
+the address the call came in on; a `web.trusted_proxies` that is set must list `127.0.0.1`. The plain HTTP ports stay as
+`web.listen` and the manager's `listen` set them. `docker.exposed_ports` may not take port 80 or
+the HTTPS ports while `https.enabled` is `true`.
+
+```bash
+curl https://router.example.com:7444/status
+```
+
+## Metrics
+
+While `metrics.enabled` is `true`, `vpn-router-setup` runs `vpn-router-metrics`, which every minute
+takes a sample of the router with `psutil`:
+
+- the CPU utilization;
+- the memory used and in total;
+- the free and the total space of `/`;
+- the bytes received and sent per second on the external and the internal interface;
+- the 1, 5 and 15 minute load averages;
+- the VPN clients of each enabled VPN system: road-warrior (IPsec P2S) and OpenVPN clients, and
+  WireGuard peers with a handshake in the last 3 minutes;
+- for each site-to-site connection that is set up: whether it is up (1 or 0), the bytes and the
+  packets per second received and sent through its child SAs since the previous sample, and the
+  seconds its IKE SA has been up. The child SAs' counters start again at a rekey; a counter lower
+  than in the previous sample counts from zero.
+
+### History
+
+The samples are kept in the router's PostgreSQL database, the one of the refresh tokens
+(`web.database`), in four detail tables, one row per minute, and per interface, kind of client or
+site-to-site connection, and each is summarized hourly, daily, monthly and yearly. A summary row
+has the start of its period, in UTC, and the average and the maximum of each value; the average
+of a connection's `up` is the part of the period it was up:
+
+| Level | Tables | Kept |
+|---|---|---|
+| Details | `metrics_system`, `metrics_network`, `metrics_vpn`, `metrics_site_to_site` | `metrics.keep_details` |
+| Hourly | `metrics_system_hourly`, `metrics_network_hourly`, `metrics_vpn_hourly`, `metrics_site_to_site_hourly` | `metrics.keep_hourly` |
+| Daily | `metrics_system_daily`, `metrics_network_daily`, `metrics_vpn_daily`, `metrics_site_to_site_daily` | `metrics.keep_daily` |
+| Monthly | `metrics_system_monthly`, `metrics_network_monthly`, `metrics_vpn_monthly`, `metrics_site_to_site_monthly` | `metrics.keep_monthly` |
+| Yearly | `metrics_system_yearly`, `metrics_network_yearly`, `metrics_vpn_yearly`, `metrics_site_to_site_yearly` | `metrics.keep_yearly` |
+
+`metrics_site_to_site` has the columns `connection`, `up`, `rx`, `tx`, `packets_rx`, `packets_tx`
+and `uptime`.
+
+How it works:
+
+- **Summaries:** a period is summarized once it is complete, from the level below. A stopped service catches up on the periods it missed, as long as their rows are still kept.
+- **Garbage collection:** runs on start and once a day. It deletes the rows older than their retention, a count and a unit such as `24 hours`, `3 months` or `10 years`.
+- **History API:** `GET /metrics/history?range=hour|day|month|year` of the status web service, protected like `/config`, answers the views of the Router Manager's Metrics tab. Each point has the system values, `network` by interface, `clients` by kind and `site_to_site` by connection, each value as its `avg` and `max`:
+
+  | Range | Bucket | Source |
+  |---|---|---|
+  | `hour` | 1 minute | details |
+  | `day` | 10 minutes | details |
+  | `month` | 6 hours | hourly |
+  | `year` | 1 month | monthly |
+
+### Scraping
+
+`GET /metrics` of the metrics service serves the last sample in the Prometheus text format, written by `prometheus_client`.
+
+- **Metric names:** the OpenTelemetry semantic convention names in their Prometheus form:
+  - `system_cpu_utilization`;
+  - `system_memory_usage_bytes` and `system_memory_limit_bytes`;
+  - `system_filesystem_usage_bytes` and `system_filesystem_utilization`;
+  - `system_network_io_bytes_total`;
+  - `system_cpu_load_average_1m`, `_5m` and `_15m`;
+  - `vpn_router_clients`, by `kind`: `p2s`, `openvpn` and `wireguard`;
+  - by `connection`, for each site-to-site connection: `vpn_router_site_to_site_up`, `vpn_router_site_to_site_uptime_seconds`, and, by `direction` too, `vpn_router_site_to_site_io_bytes_per_second` and `vpn_router_site_to_site_packets_per_second`. The rates are gauges, since the child SAs' counters start again at each rekey.
+- **Listening:** on the interfaces `metrics.listen` names, `internal` by default, at `metrics.port`, and on `127.0.0.1`. While HTTPS is on, Caddy serves it at `metrics.https_port` for `wan.local_fqdn`. `vpn-router-setup` opens both ports on the internal and the external interface.
+- **Authentication:** HTTP Basic as the service account `metrics.service_account` names, `metrics` by default. The password is checked with a bind to the user directory, so 5 failed attempts lock the account as for any user.
+- **The account:** `vpn-router-setup` owns it while metrics are enabled.
+  - It adds the account with a random password, which it writes to `/etc/vpn-router/metrics.secret` (root only). Give that password to the collector.
+  - When the file is missing or no longer holds the account's password, setup sets a new random password and ends any lockout. Delete the file and restart `vpn-router-setup` to change the password.
+  - A disabled account is left as it is.
+  - A user of that name who is not a service account is a setup failure.
+
+An OpenTelemetry Collector scrapes it with its `prometheus` receiver:
+
+```yaml
+receivers:
+  prometheus:
+    config:
+      scrape_configs:
+        - job_name: vpn-router
+          scrape_interval: 60s
+          scheme: https
+          basic_auth:
+            username: metrics
+            password_file: /etc/otelcol/vpn-router-metrics.secret   # a copy of /etc/vpn-router/metrics.secret
+          static_configs:
+            - targets: ['router.example.com:9465']
+```
+
+### Pushing
+
+When `metrics.otlp_endpoint` is set, every sample is also pushed there as an OTLP/HTTP JSON request.
+
+- **Content:** the semantic convention names (`system.cpu.utilization`, `system.network.io` and so on), `vpn_router.clients`, the gauges `vpn_router.site_to_site.up`, `.uptime`, `.io` and `.packets` with the attribute `connection`, and the resource attributes `service.name` `vpn-router` and `host.name`.
+- **Authentication:** HTTP Basic with `metrics.otlp_username` and `metrics.otlp_password` when they are set.
+- **Failures:** a failed push is logged and not repeated; the next sample is pushed a minute later.
+
 ## Router Manager

 The `vpn-router-manager` package, built in the repository `linux-cloud-router-manager`, is a web
-application that shows the state of the router and manages its users through the status web
-service. It can be installed on the router or on another Linux system. While it is installed on
+application that shows the state of the router and manages its users and site-to-site
+connections through the status web service. It can be installed on the router or on another Linux system. While it is installed on
 the router, `vpn-router-setup` opens its port (`port` in `/etc/vpn-router-manager/manager.json`,
-7080 by default, HTTP; 7443 is kept for it with TLS) on the internal and the external
+7080 by default, HTTP; HTTPS is Caddy's, on `https.manager_port`) on the internal and the external
 interface; restart `vpn-router-setup` after changing it. The manager's `listen` chooses the
 interfaces it listens on.

 ## Removal

 `apt-get remove` stops `vpn-router-docker`, which removes the Docker rules. It terminates the
-tunnels and takes `wg-quick@wg0` and `openvpn-server@vpn-router` down, but leaves the
+tunnels and takes `wg-quick@wg0`, `openvpn-server@vpn-router`, `caddy` and `vpn-router-metrics`
+down, but leaves the
 configuration in place. `strongswan` is left enabled, since it is a shared service that
 may be in use by something else.

 `apt-get purge` additionally removes the generated files and the firewall rules, restoring
 `/etc/ufw/before.rules` to its original content, and hands `vpn-router.json` back to `ucf`
 before deleting it so a later reinstall starts clean. It also removes the web service's
-signing key, and the refresh tokens' database, its role and their password file when the package
-created them. Key material and users are never deleted: `/etc/vpn-router/pki`, `/etc/vpn-router/ldap`, the user directory in slapd, the
+signing key, the password file of the metrics service account, and the database of the refresh
+tokens and the metrics, its role and their password
+file when the package created them, and Caddy's configuration `/etc/caddy/vpn-router.Caddyfile`; the certificate in
+`/var/lib/caddy` belongs to the `caddy` package. Key material and users are never deleted: `/etc/vpn-router/pki`, `/etc/vpn-router/ldap`, the user directory in slapd, the
 WireGuard key pair and everything under `/etc/swanctl` are left alone.

 ## Building
@@ -1,3 +1,201 @@
+vpn-router (0.18.3-1) unstable; urgency=medium
+
+  fix: internal service accounts are the router's own, of which the metrics service's is the one at present, and the documentation says what a service account is.
+
+  * /service-accounts, /groups and the internal field of the answers
+    take every internal service account, the accounts the router creates
+    and manages for its own services, instead of only the metrics
+    service's; the 403 answers say that the router manages them.
+  * The README, the ADR and the users module describe a service account
+    as the account another system, such as an OpenTelemetry Collector
+    reading /metrics, signs in with, and the internal ones as managed by
+    the router.
+
+ -- Slawomir Koszewski <slawek@koszewscy.waw.pl>  Mon, 26 Oct 2026 19:00:00 +0100
+
+vpn-router (0.18.2-1) unstable; urgency=medium
+
+  fix: service accounts are managed at /service-accounts, not /users, and the internal one of the metrics service is only listed.
+
+  * /service-accounts, for members of admins and admin tokens, lists the
+    service accounts, adds one with a password and an optional e-mail
+    address, changes the e-mail address, sets the password, disables,
+    enables, unlocks and removes them.
+  * /users no longer lists service accounts or takes "service" on POST,
+    and answers 404 to a request naming one.
+  * /service-accounts answers 403 to every request but the list on the
+    account metrics.service_account names while metrics are enabled, and
+    /groups to putting it in or taking it out of a group;
+    vpn-router-setup and root's vpn-router-user still change it.
+
+ -- Slawomir Koszewski <slawek@koszewscy.waw.pl>  Mon, 26 Oct 2026 18:00:00 +0100
+
+vpn-router (0.18.1-1) unstable; urgency=medium
+
+  fix: vpn-router-setup owns only the creation of the metrics service's account, which is marked internal, and administrators add service accounts with vpn-router-user add --service and /users.
+
+  * POST /users takes "service": true and adds a service account, which
+    cannot sign in to /auth; vpn-router-user add takes --service.
+  * The users of /users and vpn-router-user have internal, true for the
+    account metrics.service_account names while metrics are enabled;
+    vpn-router-user list shows its kind as internal.
+  * PUT /users/<name>/password refuses the internal service account,
+    whose password vpn-router-setup keeps.
+
+ -- Slawomir Koszewski <slawek@koszewscy.waw.pl>  Mon, 26 Oct 2026 17:00:00 +0100
+
+vpn-router (0.18.0-2) unstable; urgency=medium
+
+  update: release.py tags a Debian revision other than 1 as x.y.z-n.
+
+  * release.py tags the newest entry x.y.z for the Debian revision 1 and
+    x.y.z-n for a later revision, so a packaging change gets a release
+    of its own.
+
+ -- Slawomir Koszewski <slawek@koszewscy.waw.pl>  Mon, 26 Oct 2026 14:00:00 +0100
+
+vpn-router (0.18.0-1) unstable; urgency=medium
+
+  feature: site_to_site holds any number of named site-to-site connections, which /site-to-site lists, adds, changes and removes.
+
+  * site_to_site maps a connection name to addrs, id, cidrs, local_cidrs,
+    local_id_mode, psk and psk_file; it replaces remote and
+    wan.local_id_mode, and a configuration with them is refused.
+  * The install answers fill the connection remote-site; the local subnets
+    fill both its local_cidrs and local.cidrs.
+  * Every ready connection is written to
+    /etc/swanctl/conf.d/site-to-site.conf as the swanctl connection and
+    child of its name with the secret ike-psk-<name>; remote-site.conf is
+    no longer written.
+  * Traffic from each connection's local_cidrs to its cidrs is not
+    masqueraded.
+  * /site-to-site, for members of admins and admin tokens, lists the
+    connections without their keys, adds, changes and removes them, and
+    restarts vpn-router-setup to apply the change.
+  * vpn-config-edit sets site_to_site.NAME.option, creating the
+    connection, and removes site_to_site.NAME; it and the web service
+    write vpn-router.json under one lock.
+  * The status shows site_to_site.connections, whether each connection is
+    established.
+  * The metrics service keeps, per site-to-site connection, whether it is
+    up, the bytes and packets per second received and sent, and the
+    seconds its IKE SA has been up, in metrics_site_to_site and its
+    summaries; /metrics/history has them in site_to_site of each point.
+  * /metrics serves vpn_router_site_to_site_up,
+    vpn_router_site_to_site_uptime_seconds,
+    vpn_router_site_to_site_io_bytes_per_second and
+    vpn_router_site_to_site_packets_per_second by connection, and the
+    OTLP push the vpn_router.site_to_site gauges; vpn_router_clients and
+    metrics_vpn no longer have the kind site_to_site.
+  * /config shows each connection in network.site_to_site, and no psk at
+    any level of the configuration.
+  * Removing the package terminates every site-to-site connection; purging
+    removes site-to-site.conf.
+
+ -- Slawomir Koszewski <slawek@koszewscy.waw.pl>  Sun, 25 Oct 2026 23:00:00 +0100
+
+vpn-router (0.17.0-1) unstable; urgency=medium
+
+  feature: /config shows the router's PostgreSQL clusters and their settings, and /postgresql their databases with their sizes.
+
+  * /config has a postgresql section: each cluster of pg_lsclusters with
+    its version, name, port, status and data directory, and the main
+    settings of each online cluster.
+  * /postgresql, protected like /config, lists the databases of each
+    online cluster with owner, encoding and size, and the total size.
+
+ -- Slawomir Koszewski <slawek@koszewscy.waw.pl>  Sun, 25 Oct 2026 21:00:00 +0200
+
+vpn-router (0.16.0-1) unstable; urgency=medium
+
+  feature: the router keeps its metrics in PostgreSQL, serves them for an OpenTelemetry Collector and pushes them over OTLP.
+
+  * vpn-router-metrics takes a sample every minute: CPU, memory, free
+    space of /, bytes per second on the external and the internal
+    interface, the load averages, and the VPN clients of each enabled
+    system.
+  * The samples are kept in metrics_system, metrics_network and
+    metrics_vpn, and summarized hourly, daily, monthly and yearly in
+    their _hourly, _daily, _monthly and _yearly tables; once a day the
+    rows older than metrics.keep_details, keep_hourly, keep_daily,
+    keep_monthly and keep_yearly are deleted.
+  * /metrics serves the last sample in the Prometheus format on the
+    interfaces metrics.listen names (internal by default) at
+    metrics.port, and over HTTPS by Caddy at metrics.https_port, with
+    HTTP Basic authentication of the service account
+    metrics.service_account names (metrics by default).
+  * metrics.otlp_endpoint pushes every sample as OTLP/HTTP JSON, with
+    metrics.otlp_username and metrics.otlp_password.
+  * /metrics/history of the web service answers the hour, day, month
+    and year views for the Router Manager.
+  * vpn-router-setup adds and keeps that service account, which cannot
+    sign in to /auth, with a random password in
+    /etc/vpn-router/metrics.secret, set anew when the file is missing.
+  * Depends on python3-psutil and python3-prometheus-client.
+
+ -- Slawomir Koszewski <slawek@koszewscy.waw.pl>  Sun, 25 Oct 2026 19:00:00 +0200
+
+vpn-router (0.15.0-1) unstable; urgency=medium
+
+  feature: vpn-config-edit shows and changes the router's configuration.
+
+  * vpn-config-edit show prints /etc/vpn-router/vpn-router.json as
+    indented JSON.
+  * vpn-config-edit set SECTION.OPTION VALUE converts the value to the
+    setting's type, checks the whole configuration as vpn-router-setup
+    does, writes the file indented with mode 0600, and reminds that
+    vpn-router-setup applies it.
+
+ -- Slawomir Koszewski <slawek@koszewscy.waw.pl>  Sun, 25 Oct 2026 18:00:00 +0200
+
+vpn-router (0.14.1-1) unstable; urgency=medium
+
+  fix: web.status_content is basic by default.
+
+  * Without web.status_content, or with a value that is not allowed, /
+    and /status show only the overall status, the time and the Client
+    IP; set it to standard or full to show more.
+
+ -- Slawomir Koszewski <slawek@koszewscy.waw.pl>  Sun, 25 Oct 2026 17:00:00 +0200
+
+vpn-router (0.14.0-1) unstable; urgency=medium
+
+  feature: the status page shows the Client IP, and web.status_content sets how much it shows.
+
+  * / and /status show the Client IP, the address the request came from:
+    the last X-Forwarded-For entry for a request from a trusted proxy, so
+    behind Caddy or the Router Manager the browser's; /status has it as
+    client_ip.
+  * web.status_content sets what / and /status show: basic the overall
+    status, the time and the Client IP; standard also the package
+    versions and the number of active and failed services; full, the
+    default, everything as before. /status names it in content.
+
+ -- Slawomir Koszewski <slawek@koszewscy.waw.pl>  Sun, 25 Oct 2026 16:00:00 +0200
+
+vpn-router (0.13.0-1) unstable; urgency=medium
+
+  feature: Caddy serves the status page and the Router Manager over HTTPS with a certificate from Let's Encrypt.
+
+  * The package depends on caddy. While https.enabled is true, the
+    default, and wan.local_fqdn is set, vpn-router-setup writes
+    /etc/caddy/vpn-router.Caddyfile and runs Caddy, which serves the
+    status page on https.web_port (7444) and the Router Manager, when it
+    is installed, on https.manager_port (7443) for wan.local_fqdn, and
+    obtains the certificate from Let's Encrypt with the HTTP challenge.
+  * The package's drop-in for caddy.service makes Caddy read that file
+    and keeps it from starting before the file exists. The file belongs
+    to root and the group caddy, which Caddy runs as, with mode 0640.
+  * The firewall opens port 80 on the external interface and the HTTPS
+    ports on both interfaces while HTTPS is on.
+  * The web service also listens on 127.0.0.1, where Caddy calls it.
+  * docker.exposed_ports may not take port 80 or the HTTPS ports while
+    HTTPS is on.
+  * Removing the package stops and disables caddy; purging it removes
+    /etc/caddy/vpn-router.Caddyfile.
+
+ -- Slawomir Koszewski <slawek@koszewscy.waw.pl>  Sun, 25 Oct 2026 15:00:00 +0200
+
 vpn-router (0.12.3-1) unstable; urgency=medium

  fix: the web service listens on the internal address, the external address or both.
@@ -23,19 +23,23 @@ Depends: ${misc:Depends},
         python3-ldap,
         python3-pyotp,
         python3-psycopg,
+         python3-psutil,
+         python3-prometheus-client,
         postgresql,
         slapd,
         openvpn,
         openvpn-auth-ldap,
         iproute2,
-         systemd-resolved
+         systemd-resolved,
+         caddy
 Description: Linux VPN router with IPSec, road-warrior, OpenVPN and WireGuard support
 Configures a Linux host or virtual machine as a VPN router: site-to-site
 IKEv2 IPSec (strongSwan swanctl), optional road-warrior access using EAP-TLS,
 optional OpenVPN with a certificate and a password per user, kept in a local
 LDAP directory, optional WireGuard, and the routing, NAT, MSS clamping and
- firewall rules a router needs. Nothing in the package is specific to a cloud
- provider.
+ firewall rules a router needs. It keeps metrics of the router in PostgreSQL
+ and serves them for an OpenTelemetry Collector. Nothing in the package is
+ specific to a cloud provider.
 .
 Settings live in /etc/vpn-router/vpn-router.json, which is created on first
 install and owned by the administrator afterwards. Editing it and restarting
@@ -5,18 +5,23 @@ src/usr/lib/vpn-router/vpnrouter_net.py               usr/lib/vpn-router/
 src/usr/lib/vpn-router/vpnrouter_serve.py             usr/lib/vpn-router/
 src/usr/lib/vpn-router/vpnrouter_users.py             usr/lib/vpn-router/
 src/usr/lib/vpn-router/vpnrouter_auth.py              usr/lib/vpn-router/
+src/usr/lib/vpn-router/vpnrouter_metrics.py           usr/lib/vpn-router/
+src/usr/lib/vpn-router/vpnrouter_status.py            usr/lib/vpn-router/
 src/usr/lib/vpn-router/openvpn-same-user              usr/lib/vpn-router/
 src/usr/sbin/vpn-router-user                          usr/sbin/
 src/usr/sbin/vpn-router-group                         usr/sbin/
 src/usr/sbin/vpn-router-token                         usr/sbin/
+src/usr/sbin/vpn-config-edit                          usr/sbin/
 src/usr/lib/vpn-router/simple-ca                      usr/lib/vpn-router/
 src/usr/lib/vpn-router/configure                      usr/lib/vpn-router/
 src/usr/lib/vpn-router/docker-rules                   usr/lib/vpn-router/
 src/usr/lib/vpn-router/setup                          usr/lib/vpn-router/
 src/usr/lib/vpn-router/web                            usr/lib/vpn-router/
+src/usr/lib/vpn-router/metrics                        usr/lib/vpn-router/
 src/usr/lib/vpn-router/bootstrap                      usr/lib/vpn-router/
 src/usr/lib/vpn-router/wait-for-libpq                 usr/lib/vpn-router/
 src/usr/lib/vpn-router/generate-config                usr/lib/vpn-router/
 src/usr/lib/vpn-router/vpnrouter_platforms/*.py       usr/lib/vpn-router/vpnrouter_platforms/
 src/usr/share/vpn-router/templates/*                  usr/share/vpn-router/templates/
+src/usr/lib/systemd/system/caddy.service.d/vpn-router.conf usr/lib/systemd/system/caddy.service.d/
 src/usr/share/doc/vpn-router/vpn-router.json.example  usr/share/doc/vpn-router/
@@ -11,10 +11,10 @@ strip_ufw_blocks() {

    tmp="$(mktemp)"
    awk '
-        /^# (IPSEC|WIREGUARD|OPENVPN|P2S DNS|WEB|BOOTSTRAP|MANAGER|ROUTER FORWARD|ROUTER NAT|ROUTER MSS) RULES START$/ {
+        /^# (IPSEC|WIREGUARD|OPENVPN|P2S DNS|WEB|BOOTSTRAP|MANAGER|HTTPS|METRICS|ROUTER FORWARD|ROUTER NAT|ROUTER MSS) RULES START$/ {
            skip = 1; pending = 0; next
        }
-        /^# (IPSEC|WIREGUARD|OPENVPN|P2S DNS|WEB|BOOTSTRAP|MANAGER|ROUTER FORWARD|ROUTER NAT|ROUTER MSS) RULES END$/ {
+        /^# (IPSEC|WIREGUARD|OPENVPN|P2S DNS|WEB|BOOTSTRAP|MANAGER|HTTPS|METRICS|ROUTER FORWARD|ROUTER NAT|ROUTER MSS) RULES END$/ {
            skip = 0; next
        }
        skip { next }
@@ -43,14 +43,16 @@ case "$1" in
            ucfr --purge vpn-router /etc/vpn-router/vpn-router.json
        fi

-        rm -f /etc/swanctl/conf.d/remote-site.conf \
+        rm -f /etc/swanctl/conf.d/site-to-site.conf \
              /etc/swanctl/conf.d/road-warrior.conf \
              /etc/systemd/resolved.conf.d/p2s-forwarder.conf \
              /etc/wireguard/wg0.conf \
              /etc/openvpn/server/vpn-router.conf \
              /etc/openvpn/server/vpn-router-ldap.conf \
+              /etc/caddy/vpn-router.Caddyfile \
              /etc/vpn-router/vpn-router.json \
              /etc/vpn-router/web.key \
+              /etc/vpn-router/metrics.secret \
              /var/lib/vpn-router/setup.done
        rmdir --ignore-fail-on-non-empty /var/lib/vpn-router 2>/dev/null || true

@@ -6,15 +6,21 @@ case "$1" in
        # Stop offering the tunnels, but leave strongSwan itself enabled: it is
        # a shared service and may be in use by something other than this
        # package. The connection files are removed on purge.
+        # The site-to-site connections are the names of site_to_site in vpn-router.json.
        if [ -d /run/systemd/system ]; then
-            swanctl --terminate --ike remote-site >/dev/null 2>&1 || true
+            connections="$(python3 -c 'import json, sys; print(" ".join(json.load(open(sys.argv[1])).get("site_to_site", {})))' \
+                /etc/vpn-router/vpn-router.json 2>/dev/null || true)"
+            for connection in $connections; do
+                swanctl --terminate --ike "$connection" >/dev/null 2>&1 || true
+            done
            swanctl --terminate --ike road-warrior >/dev/null 2>&1 || true
        fi

-        # This package enabled wg-quick@wg0 and openvpn-server@vpn-router, so
-        # it takes them down again. Use the debhelper wrappers rather than
-        # systemctl, so the script behaves on a machine without systemd.
-        for unit in wg-quick@wg0.service openvpn-server@vpn-router.service; do
+        # vpn-router-setup enabled wg-quick@wg0, openvpn-server@vpn-router,
+        # caddy and vpn-router-metrics, so the package takes them down again.
+        # Use the debhelper wrappers rather than systemctl, so the script
+        # behaves on a machine without systemd.
+        for unit in wg-quick@wg0.service openvpn-server@vpn-router.service caddy.service vpn-router-metrics.service; do
            if command -v deb-systemd-invoke >/dev/null 2>&1; then
                deb-systemd-invoke stop "$unit" >/dev/null 2>&1 || true
            fi
@@ -6,4 +6,5 @@ override_dh_installsystemd:
 	dh_installsystemd --name=vpn-router-setup
 	dh_installsystemd --name=vpn-router-docker
 	dh_installsystemd --name=vpn-router-web --no-start
+	dh_installsystemd --name=vpn-router-metrics --no-enable --no-start
 	dh_installsystemd --name=vpn-router-bootstrap --no-enable --no-start
@@ -66,7 +66,8 @@ Type: select
 Choices: fqdn, public_ip, internal_ip
 Default: fqdn
 Description: IKE local identity mode:
- How to derive the IKE identity advertised to the remote site:
+ How to derive the IKE identity the first site-to-site connection
+ advertises to the remote site:
 .
 fqdn - use the FQDN, which must match what the peer expects.
 .
@@ -78,8 +79,9 @@ Template: vpn-router/local_cidrs
 Type: string
 Default:
 Description: Local subnet CIDR(s):
- Comma-separated list of local subnet CIDRs to advertise into the
- site-to-site tunnel (for example 10.0.0.0/24 or 10.0.0.0/24,10.0.1.0/24).
+ Comma-separated list of local subnet CIDRs routed by this router and
+ advertised into the first site-to-site connection (for example
+ 10.0.0.0/24 or 10.0.0.0/24,10.0.1.0/24).

 Template: vpn-router/int_gateway_ip
 Type: string
@@ -94,25 +96,26 @@ Type: string
 Default:
 Description: Remote site WAN IP address(es):
 Comma-separated list of remote gateway addresses or FQDNs for the
- site-to-site IPSec tunnel.
+ first site-to-site connection.

 Template: vpn-router/remote_id
 Type: string
 Default:
 Description: Remote site IKE identity:
- IKE identity of the remote peer, without a leading @.
+ IKE identity of the remote peer of the first site-to-site connection,
+ without a leading @.

 Template: vpn-router/remote_cidrs
 Type: string
 Default:
 Description: Remote subnet CIDR(s):
 Comma-separated list of remote subnet CIDRs reachable through the
- site-to-site tunnel (for example 192.168.0.0/24).
+ first site-to-site connection (for example 192.168.0.0/24).

 Template: vpn-router/psk
 Type: password
 Description: Pre-shared key (PSK):
- Pre-shared key for the site-to-site IKEv2 tunnel. Must match the value
+ Pre-shared key of the first site-to-site connection. Must match the value
 configured on the remote peer. Stored in the configuration file and cleared
 from the debconf database after installation.

@@ -0,0 +1,22 @@
+[Unit]
+Description=VPN Router metrics service
+Documentation=file:/usr/share/doc/vpn-router/README.md
+After=network-online.target postgresql.service vpn-router-web.service
+Wants=network-online.target
+
+[Service]
+Type=simple
+ExecStartPre=/usr/lib/vpn-router/wait-for-libpq
+ExecStart=/usr/bin/python3 /usr/lib/vpn-router/metrics
+TimeoutStartSec=5min
+Restart=on-failure
+RestartSec=15
+NoNewPrivileges=yes
+ProtectSystem=strict
+RuntimeDirectory=vpn-router
+RuntimeDirectoryPreserve=yes
+ProtectHome=yes
+PrivateTmp=yes
+
+[Install]
+WantedBy=multi-user.target
@@ -0,0 +1,10 @@
+# Caddy is the HTTPS proxy of vpn-router: it reads the configuration vpn-router-setup writes, and
+# does not start until that exists.
+[Unit]
+ConditionPathExists=/etc/caddy/vpn-router.Caddyfile
+
+[Service]
+ExecStart=
+ExecStart=/usr/bin/caddy run --environ --adapter caddyfile --config /etc/caddy/vpn-router.Caddyfile
+ExecReload=
+ExecReload=/usr/bin/caddy reload --adapter caddyfile --config /etc/caddy/vpn-router.Caddyfile --force
@@ -18,7 +18,9 @@ on the next dpkg-reconfigure.

 Answers arrive as VPN_ROUTER_* environment variables and are converted to the
 type of the setting they fill: comma-separated lists become arrays, "true" and
-"false" become booleans and digits become integers.
+"false" become booleans and digits become integers. The site-to-site answers
+fill the connection vpnrouter.FIRST_CONNECTION of site_to_site; the local
+subnets fill both its local_cidrs and local.cidrs.
 """

 import json
@@ -29,27 +31,29 @@ sys.path.insert(0, os.path.dirname(os.path.realpath(__file__)))

 import vpnrouter

-# environment variable -> (section, option)
+FIRST = ('site_to_site', vpnrouter.FIRST_CONNECTION)
+
+# environment variable -> the settings it fills, each (section, option) or (site_to_site, name, option)
 ANSWERS = {
-    'VPN_ROUTER_PLATFORM':        ('general', 'platform'),
-    'VPN_ROUTER_MODE':            ('general', 'mode'),
-    'VPN_ROUTER_INT_ADDR':        ('local', 'int_addr'),
-    'VPN_ROUTER_EXTERNAL_INTERFACE': ('interfaces', 'external'),
-    'VPN_ROUTER_INTERNAL_INTERFACE': ('interfaces', 'internal'),
-    'VPN_ROUTER_LOCAL_FQDN':      ('wan', 'local_fqdn'),
-    'VPN_ROUTER_LOCAL_ID_MODE':   ('wan', 'local_id_mode'),
-    'VPN_ROUTER_LOCAL_CIDRS':     ('local', 'cidrs'),
-    'VPN_ROUTER_INT_GATEWAY_IP':  ('local', 'int_gateway_ip'),
-    'VPN_ROUTER_REMOTE_ADDRS':    ('remote', 'addrs'),
-    'VPN_ROUTER_REMOTE_ID':       ('remote', 'id'),
-    'VPN_ROUTER_REMOTE_CIDRS':    ('remote', 'cidrs'),
-    'VPN_ROUTER_PSK':             ('remote', 'psk'),
-    'VPN_ROUTER_P2S_ENABLED':     ('p2s', 'enabled'),
-    'VPN_ROUTER_P2S_ADDRESS_POOL': ('p2s', 'address_pool'),
-    'VPN_ROUTER_P2S_CA_NAME':     ('p2s', 'ca_name'),
-    'VPN_ROUTER_WG_ENABLED':      ('wireguard', 'enabled'),
-    'VPN_ROUTER_WG_ADDRESS':      ('wireguard', 'address'),
-    'VPN_ROUTER_WG_LISTEN_PORT':  ('wireguard', 'listen_port'),
+    'VPN_ROUTER_PLATFORM':        (('general', 'platform'),),
+    'VPN_ROUTER_MODE':            (('general', 'mode'),),
+    'VPN_ROUTER_INT_ADDR':        (('local', 'int_addr'),),
+    'VPN_ROUTER_EXTERNAL_INTERFACE': (('interfaces', 'external'),),
+    'VPN_ROUTER_INTERNAL_INTERFACE': (('interfaces', 'internal'),),
+    'VPN_ROUTER_LOCAL_FQDN':      (('wan', 'local_fqdn'),),
+    'VPN_ROUTER_LOCAL_ID_MODE':   ((*FIRST, 'local_id_mode'),),
+    'VPN_ROUTER_LOCAL_CIDRS':     (('local', 'cidrs'), (*FIRST, 'local_cidrs')),
+    'VPN_ROUTER_INT_GATEWAY_IP':  (('local', 'int_gateway_ip'),),
+    'VPN_ROUTER_REMOTE_ADDRS':    ((*FIRST, 'addrs'),),
+    'VPN_ROUTER_REMOTE_ID':       ((*FIRST, 'id'),),
+    'VPN_ROUTER_REMOTE_CIDRS':    ((*FIRST, 'cidrs'),),
+    'VPN_ROUTER_PSK':             ((*FIRST, 'psk'),),
+    'VPN_ROUTER_P2S_ENABLED':     (('p2s', 'enabled'),),
+    'VPN_ROUTER_P2S_ADDRESS_POOL': (('p2s', 'address_pool'),),
+    'VPN_ROUTER_P2S_CA_NAME':     (('p2s', 'ca_name'),),
+    'VPN_ROUTER_WG_ENABLED':      (('wireguard', 'enabled'),),
+    'VPN_ROUTER_WG_ADDRESS':      (('wireguard', 'address'),),
+    'VPN_ROUTER_WG_LISTEN_PORT':  (('wireguard', 'listen_port'),),
 }


@@ -74,23 +78,28 @@ def main():
            vpnrouter.fail(f'cannot parse {vpnrouter.CONFIG_FILE}: the top level is not an object')

    answered = False
-    for variable, (section, option) in ANSWERS.items():
-        value = os.environ.get(variable)
-        if not value:
+    for variable, paths in ANSWERS.items():
+        answer = os.environ.get(variable)
+        if not answer:
            continue
-        # A value that does not convert is kept as a string for validate() to report.
-        default = vpnrouter.SCHEMA[section][option]
-        if isinstance(default, bool):
-            value = value == 'true'
-        elif isinstance(default, int):
-            value = int(value) if value.isdigit() else value
-        elif isinstance(default, list):
-            value = [item.strip() for item in value.split(',') if item.strip()]
-        if not isinstance(cfg.get(section, {}), dict):
-            vpnrouter.fail(f'cannot parse {vpnrouter.CONFIG_FILE}: {section} is not an object')
-        if cfg.setdefault(section, {}).get(option) != value:
-            cfg[section][option] = value
-            answered = True
+        for path in paths:
+            # A value that does not convert is kept as a string for validate() to report.
+            default = vpnrouter.CONNECTION[path[2]] if path[0] == 'site_to_site' else vpnrouter.SCHEMA[path[0]][path[1]]
+            value = answer
+            if isinstance(default, bool):
+                value = value == 'true'
+            elif isinstance(default, int):
+                value = int(value) if value.isdigit() else value
+            elif isinstance(default, list):
+                value = [item.strip() for item in value.split(',') if item.strip()]
+            target = cfg
+            for key in path[:-1]:
+                if not isinstance(target.setdefault(key, {}), dict):
+                    vpnrouter.fail(f'cannot parse {vpnrouter.CONFIG_FILE}: {".".join(path[:-1])} is not an object')
+                target = target[key]
+            if target.get(path[-1]) != value:
+                target[path[-1]] = value
+                answered = True

    # Without a change the candidate is the current file byte for byte, as ucf compares checksums.
    with open(output, 'w', encoding='utf-8') as handle:
@@ -0,0 +1,456 @@
+#!/usr/bin/python3
+"""Collect the metrics of the router, keep them in PostgreSQL, serve them for scraping and push them with OTLP.
+
+Run by vpn-router-metrics.service while metrics.enabled is true; vpn-router-setup enables and
+disables the unit.
+
+Every SAMPLE_SECONDS, on the minute, a sample is taken with psutil: the CPU utilization since the
+previous sample, the memory used and in total, the free and the total space of /, the bytes
+received and sent per second on the external and the internal interface, and the load averages;
+and the VPN clients of each enabled VPN system (vpnrouter_status): road-warrior (p2s) and
+OpenVPN clients and WireGuard peers with a recent handshake; and of each site-to-site connection
+that is set up, whether it is up, the bytes and packets per second through its child SAs since
+the previous sample, and how long its IKE SA has been up. The interfaces, the enabled systems and
+the connections are those vpn-router-setup resolved, read from /run/vpn-router/web.json.
+
+The sample is written to the detail tables of vpnrouter_metrics. When the clock has passed into
+a new hour, day, month or year, the complete periods are summarized, and once a day, after the
+daily summary, the rows older than their retention are deleted; both also run on start. A
+failure of the database is logged and tried again with the next sample.
+
+GET /metrics answers the last sample in the Prometheus text format, written by
+prometheus_client, with OpenTelemetry semantic convention names in their Prometheus form, for an
+OpenTelemetry Collector's prometheus receiver. It needs HTTP Basic authentication as the service
+account metrics.service_account names, which vpn-router-setup keeps with the password in
+/etc/vpn-router/metrics.secret, checked with a bind to the router's directory, so failed attempts
+lock the account as for any user. The service listens on the interfaces metrics.listen
+names and on the loopback address, where Caddy serves it over HTTPS at metrics.https_port; the
+address of a call through Caddy is the last entry of its X-Forwarded-For header.
+
+When metrics.otlp_endpoint is set, every sample is also pushed there as an OTLP/HTTP JSON
+ExportMetricsServiceRequest, with HTTP Basic authentication when metrics.otlp_username is set.
+"""
+
+import base64
+import datetime
+import json
+import os
+import signal
+import socket
+import sys
+import threading
+import time
+import urllib.error
+import urllib.request
+from http.server import BaseHTTPRequestHandler
+
+sys.path.insert(0, os.path.dirname(os.path.realpath(__file__)))
+
+import ldap
+import psutil
+from prometheus_client import CONTENT_TYPE_LATEST, generate_latest
+from prometheus_client.core import CollectorRegistry, CounterMetricFamily, GaugeMetricFamily
+
+import vpnrouter
+import vpnrouter_metrics
+import vpnrouter_net
+import vpnrouter_serve
+import vpnrouter_status
+import vpnrouter_users
+
+STATE_FILE = '/run/vpn-router/web.json'
+CONFIG_FILE = '/etc/vpn-router/vpn-router.json'
+
+SAMPLE_SECONDS = 60
+
+#: Seconds between two discoveries of where the service should listen.
+DISCOVERY_SECONDS = 30
+
+#: Seconds an OTLP push may take.
+OTLP_TIMEOUT = 10
+
+#: The mount point whose space is measured.
+MOUNTPOINT = '/'
+
+#: The last sample, as sample() makes it, or None before the first.
+_latest = {'sample': None}
+_latest_lock = threading.Lock()
+
+
+def log(message):
+    print(f'vpn-router-metrics: {message}', file=sys.stderr, flush=True)
+
+
+def read_json(path):
+    """The object in a JSON file, or {} when the file is missing or holds no object."""
+    try:
+        with open(path, encoding='utf-8') as handle:
+            data = json.load(handle)
+    except (OSError, ValueError):
+        return {}
+    return data if isinstance(data, dict) else {}
+
+
+def section(configuration, name):
+    """A section of the configuration, or {} when it is missing or not an object."""
+    value = configuration.get(name)
+    return value if isinstance(value, dict) else {}
+
+
+def clients(state):
+    """The VPN clients of each enabled VPN system, None where it cannot be asked."""
+    counts = {}
+    if state.get('p2s'):
+        counts['p2s'] = vpnrouter_status.established('road-warrior')
+    if state.get('openvpn'):
+        counts['openvpn'] = vpnrouter_status.openvpn_clients()
+    if state.get('wireguard'):
+        counts['wireguard'] = vpnrouter_status.wireguard_connected()
+    return counts
+
+
+def sample(previous):
+    """A sample of the router, with the rates since the previous sample, None for the first."""
+    state = read_json(STATE_FILE)
+    network = section(state, 'network')
+    names = [name for name in dict.fromkeys((network.get('external_interface'), network.get('internal_interface')))
+             if isinstance(name, str) and name]
+    counters = psutil.net_io_counters(pernic=True)
+    memory = psutil.virtual_memory()
+    disk = psutil.disk_usage(MOUNTPOINT)
+    load1, load5, load15 = os.getloadavg()
+    connections = state.get('site_to_site')
+    tunnels = vpnrouter_status.site_to_site_tunnels(connections) if isinstance(connections, list) and connections else {}
+    now = time.time()
+    current = {
+        'time': now,
+        'monotonic': time.monotonic(),
+        'system': {
+            'cpu': psutil.cpu_percent(interval=None),
+            'memory_used': memory.total - memory.available,
+            'memory_total': memory.total,
+            'disk_free': disk.free,
+            'disk_total': disk.total,
+            'load1': load1,
+            'load5': load5,
+            'load15': load15,
+        },
+        'counters': {name: (counters[name].bytes_recv, counters[name].bytes_sent) for name in names if name in counters},
+        'clients': clients(state),
+        'rates': {},
+        'tunnels': tunnels or {},
+        'site_to_site': {},
+    }
+    elapsed = current['monotonic'] - previous['monotonic'] if previous is not None else 0
+    if elapsed > 0:
+        for name, (received, sent) in current['counters'].items():
+            if name in previous['counters']:
+                before_received, before_sent = previous['counters'][name]
+                current['rates'][name] = (max(received - before_received, 0) / elapsed, max(sent - before_sent, 0) / elapsed)
+    # A connection's rates need its counters of the previous sample; a counter that went down was rekeyed and counts from zero.
+    for name, tunnel in current['tunnels'].items():
+        before = previous['tunnels'].get(name) if elapsed > 0 else None
+        values = {'up': tunnel['up'], 'uptime': tunnel['uptime']}
+        for value, counter in (('rx', 'bytes_in'), ('tx', 'bytes_out'), ('packets_rx', 'packets_in'), ('packets_tx', 'packets_out')):
+            if before is None:
+                values[value] = None
+            else:
+                count = tunnel[counter]
+                values[value] = (count - before[counter] if count >= before[counter] else count) / elapsed
+        current['site_to_site'][name] = values
+    return current
+
+
+def periods(moment):
+    """The hour, the day, the month and the year of a UTC moment, keyed by the levels of vpnrouter_metrics.LEVELS."""
+    return {'hourly': moment.strftime('%Y-%m-%dT%H'), 'daily': moment.strftime('%Y-%m-%d'),
+            'monthly': moment.strftime('%Y-%m'), 'yearly': moment.strftime('%Y')}
+
+
+def store(cfg, current, done):
+    """Write the sample, summarize the periods the clock has passed and collect the garbage once a day.
+
+    done holds the periods summarized so far, and garbage the day of the last garbage collection;
+    it is updated only for what succeeded.
+    """
+    now = periods(datetime.datetime.now(datetime.timezone.utc))
+    with vpnrouter_metrics.database(cfg) as connection:
+        vpnrouter_metrics.write(connection, current['system'], current['rates'], current['clients'], current['site_to_site'])
+        for level, _, _ in vpnrouter_metrics.LEVELS:
+            if done.get(level) != now[level]:
+                vpnrouter_metrics.summarize(connection, level)
+                done[level] = now[level]
+        if done.get('garbage') != now['daily']:
+            vpnrouter_metrics.collect_garbage(connection, cfg)
+            done['garbage'] = now['daily']
+
+
+def attributes(**values):
+    """OTLP attributes of string values."""
+    return [{'key': key, 'value': {'stringValue': value}} for key, value in values.items()]
+
+
+def otlp_request(current, started):
+    """The OTLP/HTTP JSON ExportMetricsServiceRequest of a sample; started is when the counters were first read, in Unix seconds."""
+    stamp = str(int(current['time'] * 1e9))
+    start = str(int(started * 1e9))
+    system = current['system']
+
+    def gauge(name, unit, points):
+        return {'name': name, 'unit': unit, 'gauge': {'dataPoints': [
+            {'timeUnixNano': stamp, 'asDouble': float(value), 'attributes': attributes(**labels)}
+            for value, labels in points if value is not None]}}
+
+    metrics = [
+        gauge('system.cpu.utilization', '1', [(system['cpu'] / 100, {})]),
+        gauge('system.memory.usage', 'By', [(system['memory_used'], {'state': 'used'})]),
+        gauge('system.memory.limit', 'By', [(system['memory_total'], {})]),
+        gauge('system.filesystem.usage', 'By', [(system['disk_free'], {'mountpoint': MOUNTPOINT, 'state': 'free'}),
+                                               (system['disk_total'] - system['disk_free'], {'mountpoint': MOUNTPOINT, 'state': 'used'})]),
+        gauge('system.filesystem.utilization', '1',
+              [(1 - system['disk_free'] / system['disk_total'] if system['disk_total'] else None, {'mountpoint': MOUNTPOINT})]),
+        gauge('system.cpu.load_average.1m', '{thread}', [(system['load1'], {})]),
+        gauge('system.cpu.load_average.5m', '{thread}', [(system['load5'], {})]),
+        gauge('system.cpu.load_average.15m', '{thread}', [(system['load15'], {})]),
+        gauge('vpn_router.clients', '{client}', [(count, {'kind': kind}) for kind, count in current['clients'].items()]),
+        gauge('vpn_router.site_to_site.up', '1', [(values['up'], {'connection': name})
+                                                 for name, values in current['site_to_site'].items()]),
+        gauge('vpn_router.site_to_site.uptime', 's', [(values['uptime'], {'connection': name})
+                                                     for name, values in current['site_to_site'].items()]),
+        gauge('vpn_router.site_to_site.io', 'By/s', [(values[value], {'connection': name, 'direction': direction})
+                                                    for name, values in current['site_to_site'].items()
+                                                    for value, direction in (('rx', 'receive'), ('tx', 'transmit'))]),
+        gauge('vpn_router.site_to_site.packets', '{packet}/s',
+              [(values[value], {'connection': name, 'direction': direction})
+               for name, values in current['site_to_site'].items()
+               for value, direction in (('packets_rx', 'receive'), ('packets_tx', 'transmit'))]),
+        {'name': 'system.network.io', 'unit': 'By', 'sum': {
+            'aggregationTemporality': 2, 'isMonotonic': True, 'dataPoints': [
+                {'startTimeUnixNano': start, 'timeUnixNano': stamp, 'asInt': str(value),
+                 'attributes': attributes(device=name, direction=direction)}
+                for name, counters in current['counters'].items()
+                for value, direction in zip(counters, ('receive', 'transmit'))]}},
+    ]
+    return {'resourceMetrics': [{
+        'resource': {'attributes': attributes(**{'service.name': 'vpn-router', 'host.name': socket.gethostname()})},
+        'scopeMetrics': [{'scope': {'name': 'vpn-router-metrics'}, 'metrics': metrics}],
+    }]}
+
+
+def push(metrics, current, started):
+    """Push the sample to metrics.otlp_endpoint; raises OSError when the collector does not take it."""
+    request = urllib.request.Request(metrics['otlp_endpoint'], data=json.dumps(otlp_request(current, started)).encode(),
+                                     headers={'Content-Type': 'application/json'}, method='POST')
+    if metrics['otlp_username']:
+        credentials = f"{metrics['otlp_username']}:{metrics['otlp_password']}".encode()
+        request.add_header('Authorization', 'Basic ' + base64.b64encode(credentials).decode())
+    with urllib.request.urlopen(request, timeout=OTLP_TIMEOUT) as response:
+        response.read()
+
+
+def collector_loop():
+    """Take a sample on every minute, store it and push it; every new failure is logged once."""
+    previous, done, reported = None, {}, {}
+    started = time.time()
+    psutil.cpu_percent(interval=None)
+
+    def report(kind, message):
+        if message != reported.get(kind):
+            if message:
+                log(message)
+            elif reported.get(kind):
+                log(f'{kind} works again')
+            reported[kind] = message
+
+    while True:
+        time.sleep(SAMPLE_SECONDS - time.time() % SAMPLE_SECONDS)
+        try:
+            cfg = vpnrouter.load_config()
+        except SystemExit as exc:
+            report('configuration', str(exc.code))
+            continue
+        report('configuration', '')
+        current = sample(previous)
+        previous = current
+        with _latest_lock:
+            _latest['sample'] = current
+        try:
+            store(cfg, current, done)
+            report('database', '')
+        except vpnrouter_metrics.DatabaseError as exc:
+            report('database', str(exc))
+        metrics = cfg['metrics']
+        if metrics['otlp_endpoint']:
+            try:
+                push(metrics, current, started)
+                report('OTLP push', '')
+            except (OSError, ValueError) as exc:
+                report('OTLP push', f"pushing to {metrics['otlp_endpoint']} failed: {exc}")
+
+
+class Sample:
+    """A prometheus_client collector of a sample."""
+
+    def __init__(self, current):
+        self.current = current
+
+    def collect(self):
+        system = self.current['system']
+        yield GaugeMetricFamily('system_cpu_utilization', 'CPU utilization since the previous sample, 0 to 1',
+                                value=system['cpu'] / 100)
+        memory = GaugeMetricFamily('system_memory_usage_bytes', 'Memory in use', labels=['state'])
+        memory.add_metric(['used'], system['memory_used'])
+        yield memory
+        yield GaugeMetricFamily('system_memory_limit_bytes', 'Total memory', value=system['memory_total'])
+        usage = GaugeMetricFamily('system_filesystem_usage_bytes', 'Space of the file system', labels=['mountpoint', 'state'])
+        usage.add_metric([MOUNTPOINT, 'free'], system['disk_free'])
+        usage.add_metric([MOUNTPOINT, 'used'], system['disk_total'] - system['disk_free'])
+        yield usage
+        if system['disk_total']:
+            utilization = GaugeMetricFamily('system_filesystem_utilization', 'Used part of the file system, 0 to 1',
+                                            labels=['mountpoint'])
+            utilization.add_metric([MOUNTPOINT], 1 - system['disk_free'] / system['disk_total'])
+            yield utilization
+        for period in ('1m', '5m', '15m'):
+            yield GaugeMetricFamily(f'system_cpu_load_average_{period}', f'Load average over {period}',
+                                    value=system[f'load{period[:-1]}'])
+        network = CounterMetricFamily('system_network_io_bytes', 'Bytes received and sent', labels=['device', 'direction'])
+        for name, (received, sent) in self.current['counters'].items():
+            network.add_metric([name, 'receive'], received)
+            network.add_metric([name, 'transmit'], sent)
+        yield network
+        vpn = GaugeMetricFamily('vpn_router_clients', 'Connected VPN clients', labels=['kind'])
+        for kind, count in self.current['clients'].items():
+            if count is not None:
+                vpn.add_metric([kind], count)
+        yield vpn
+        tunnels = self.current['site_to_site']
+        up = GaugeMetricFamily('vpn_router_site_to_site_up', 'Whether the site-to-site connection is established, 1 or 0',
+                               labels=['connection'])
+        uptime = GaugeMetricFamily('vpn_router_site_to_site_uptime_seconds', 'Seconds the IKE SA of the site-to-site connection has been up',
+                                   labels=['connection'])
+        io = GaugeMetricFamily('vpn_router_site_to_site_io_bytes_per_second',
+                               'Bytes per second received and sent through the site-to-site connection', labels=['connection', 'direction'])
+        packets = GaugeMetricFamily('vpn_router_site_to_site_packets_per_second',
+                                    'Packets per second received and sent through the site-to-site connection',
+                                    labels=['connection', 'direction'])
+        for name, values in tunnels.items():
+            up.add_metric([name], values['up'])
+            if values['uptime'] is not None:
+                uptime.add_metric([name], values['uptime'])
+            for family, received, sent in ((io, 'rx', 'tx'), (packets, 'packets_rx', 'packets_tx')):
+                for value, direction in ((received, 'receive'), (sent, 'transmit')):
+                    if values[value] is not None:
+                        family.add_metric([name, direction], values[value])
+        yield from (up, uptime, io, packets)
+
+
+def authorized(header, account):
+    """Whether an Authorization header holds the password of the service account; LDAP errors propagate."""
+    if not header.startswith('Basic '):
+        return False
+    try:
+        name, _, password = base64.b64decode(header[6:].strip(), validate=True).decode().partition(':')
+    except ValueError:
+        return False
+    if name != account:
+        return False
+    try:
+        with vpnrouter_users.session() as connection:
+            if not vpnrouter_users.service(vpnrouter_users.entry(connection, name)):
+                return False
+        vpnrouter_users.login(name, password, None)
+    except vpnrouter_users.Failure:
+        return False
+    return True
+
+
+class Handler(BaseHTTPRequestHandler):
+    protocol_version = 'HTTP/1.1'
+
+    def client(self):
+        """The client address: the last X-Forwarded-For entry of a call through Caddy on the loopback address, else the peer."""
+        peer = self.client_address[0]
+        forwarded = self.headers.get('X-Forwarded-For', '')
+        if peer == vpnrouter_net.LOOPBACK and forwarded.strip():
+            return forwarded.split(',')[-1].strip()
+        return peer
+
+    def answer(self, send_body):
+        self.principal = None
+        extra = []
+        path = self.path.split('?', 1)[0]
+        account = str(section(read_json(CONFIG_FILE), 'metrics').get('service_account',
+                                                                       vpnrouter.SCHEMA['metrics']['service_account'])).strip()
+        with _latest_lock:
+            current = _latest['sample']
+        if path != '/metrics':
+            body, kind, code = b'Not found\n', 'text/plain; charset=utf-8', 404
+        elif not account:
+            body, kind, code = b'metrics.service_account is not set\n', 'text/plain; charset=utf-8', 503
+        else:
+            try:
+                allowed = authorized(self.headers.get('Authorization', ''), account)
+            except (ldap.LDAPError, OSError) as exc:
+                allowed = None
+                body, kind, code = f'the user directory failed: {exc}\n'.encode(), 'text/plain; charset=utf-8', 500
+            if allowed is False:
+                body, kind, code = b'Unauthorized\n', 'text/plain; charset=utf-8', 401
+                extra.append(('WWW-Authenticate', 'Basic realm="vpn-router metrics", charset="UTF-8"'))
+            elif allowed:
+                self.principal = account
+                if current is None:
+                    body, kind, code = b'no sample yet\n', 'text/plain; charset=utf-8', 503
+                else:
+                    registry = CollectorRegistry()
+                    registry.register(Sample(current))
+                    body, kind, code = generate_latest(registry), CONTENT_TYPE_LATEST, 200
+        self.send_response(code)
+        self.send_header('Content-Type', kind)
+        self.send_header('Content-Length', str(len(body)))
+        self.send_header('Cache-Control', 'no-store')
+        for name, value in extra:
+            self.send_header(name, value)
+        self.end_headers()
+        if send_body:
+            self.wfile.write(body)
+
+    def do_GET(self):
+        self.answer(True)
+
+    def do_HEAD(self):
+        self.answer(False)
+
+    def log_message(self, format, *args):
+        principal = getattr(self, 'principal', None) or '-'
+        sys.stderr.write('%s - %s [%s] %s\n' % (self.client(), principal, self.log_date_time_string(), format % args))
+
+
+def wanted():
+    """Where the service listens: the addresses of the interfaces metrics.listen names and LOOPBACK, at metrics.port."""
+    configuration = read_json(CONFIG_FILE)
+    metrics = section(configuration, 'metrics')
+    defaults = vpnrouter.SCHEMA['metrics']
+    if metrics.get('enabled', defaults['enabled']) is False:
+        return [], 'metrics are disabled in the configuration'
+    port = metrics.get('port', defaults['port'])
+    if isinstance(port, bool) or not isinstance(port, int) or not 1 <= port <= 65535:
+        port = defaults['port']
+    addresses = vpnrouter_net.listen_addresses(configuration, metrics.get('listen', defaults['listen']))
+    if not addresses:
+        return [], 'the addresses to listen on are not known yet'
+    return [(address, port) for address in [*addresses, vpnrouter_net.LOOPBACK]], ''
+
+
+def main():
+    signal.signal(signal.SIGTERM, lambda *_: sys.exit(0))
+    threading.Thread(target=collector_loop, name='collector', daemon=True).start()
+    try:
+        vpnrouter_serve.serve(wanted, Handler, log, DISCOVERY_SECONDS)
+    except KeyboardInterrupt:
+        pass
+    return 0
+
+
+if __name__ == '__main__':
+    sys.exit(main())
@@ -16,10 +16,12 @@ firewall and NAT rules are written against them, so choosing the wrong one
 would be a silent and security-relevant mistake.
 """

+import grp
 import json
 import os
 import pathlib
 import re
+import secrets
 import socket
 import subprocess
 import sys
@@ -58,6 +60,15 @@ MANAGER_CONFIG = pathlib.Path('/etc/vpn-router-manager/manager.json')
 MANAGER_ADMIN  = pathlib.Path('/etc/vpn-router-manager/admin.json')
 MANAGER_PORT   = 7080

+#: The password of the metrics service account, which setup makes and keeps (root only).
+METRICS_SECRET = pathlib.Path('/etc/vpn-router/metrics.secret')
+
+#: The configuration of Caddy, the HTTPS proxy, which the package's drop-in for caddy.service names;
+#: Caddy runs as the user and group CADDY_GROUP, which the caddy package creates.
+CADDYFILE   = pathlib.Path('/etc/caddy/vpn-router.Caddyfile')
+CADDY_UNIT  = 'caddy.service'
+CADDY_GROUP = 'caddy'
+
 FILTER_ANCHOR = '# End required lines'

 #: Configuration options left out wherever the configuration is shown.
@@ -71,6 +82,8 @@ BLOCKS = (
    ('# WEB RULES START',           '# WEB RULES END'),
    ('# BOOTSTRAP RULES START',     '# BOOTSTRAP RULES END'),
    ('# MANAGER RULES START',       '# MANAGER RULES END'),
+    ('# HTTPS RULES START',         '# HTTPS RULES END'),
+    ('# METRICS RULES START',       '# METRICS RULES END'),
    ('# ROUTER FORWARD RULES START', '# ROUTER FORWARD RULES END'),
    ('# ROUTER NAT RULES START',    '# ROUTER NAT RULES END'),
    ('# ROUTER MSS RULES START',    '# ROUTER MSS RULES END'),
@@ -215,7 +228,7 @@ def filter_block(ctx):
                ]
        lines += ['# P2S DNS RULES END']

-    # The web service and the Router Manager choose their interfaces themselves, so their ports are open on both.
+    # The web service, the Router Manager and the metrics service choose their interfaces themselves, so their ports are open on both.
    interfaces = [name for name in (ctx['int_iface'], ctx['wan_iface']) if name]
    if ctx['web_enabled'] and interfaces:
        lines += [
@@ -242,6 +255,28 @@ def filter_block(ctx):
            '# MANAGER RULES END',
        ]

+    if vpnrouter.metrics_ready(ctx) and interfaces:
+        lines += [
+            '',
+            '# METRICS RULES START',
+            *(f'-A ufw-before-input -i {name} -p tcp --dport {ctx["metrics_port"]} -j ACCEPT' for name in interfaces),
+            '# METRICS RULES END',
+        ]
+
+    # Let's Encrypt reaches the HTTP challenge on the external interface; the HTTPS ports are open on both.
+    if vpnrouter.https_ready(ctx) and interfaces:
+        ports = [port for wanted, port in ((ctx['web_enabled'], ctx['https_web_port']),
+                                           (MANAGER.exists(), ctx['https_manager_port']),
+                                           (vpnrouter.metrics_ready(ctx), ctx['metrics_https_port'])) if wanted]
+        lines += [
+            '',
+            '# HTTPS RULES START',
+            *([f'-A ufw-before-input -i {ctx["wan_iface"]} -p tcp --dport {vpnrouter.ACME_HTTP_PORT} -j ACCEPT']
+              if ctx['wan_iface'] else []),
+            *(f'-A ufw-before-input -i {name} -p tcp --dport {port} -j ACCEPT' for name in interfaces for port in ports),
+            '# HTTPS RULES END',
+        ]
+
    if vpnrouter.routing_ready(ctx):
        lines += ['', '# ROUTER FORWARD RULES START']
        for subnet in ctx['local_cidr_list']:
@@ -259,7 +294,6 @@ def nat_and_mangle_block(ctx):

    if vpnrouter.routing_ready(ctx):
        subnets = ctx['local_cidr_list']
-        remote = ctx['remote_cidr_list']
        lines += [
            '',
            '# ROUTER NAT RULES START',
@@ -267,11 +301,14 @@ def nat_and_mangle_block(ctx):
            ':POSTROUTING ACCEPT [0:0]',
            '-F POSTROUTING',
        ]
-        # Every RETURN precedes every MASQUERADE, so tunnel-bound traffic
-        # escapes NAT whichever local subnet it came from.
-        for subnet in subnets:
-            for cidr in remote:
-                lines.append(f'-A POSTROUTING -s {subnet} -d {cidr} -j RETURN')
+        # Every RETURN precedes every MASQUERADE, so traffic bound for a tunnel
+        # escapes NAT; each ready connection pairs its local and remote subnets.
+        for connection in ctx['connections']:
+            if not connection['ready']:
+                continue
+            for subnet in connection['local_cidr_list']:
+                for cidr in connection['remote_cidr_list']:
+                    lines.append(f'-A POSTROUTING -s {subnet} -d {cidr} -j RETURN')
        for subnet in subnets:
            lines.append(
                f'-A POSTROUTING -s {subnet} -o {ctx["wan_iface"]} -j MASQUERADE')
@@ -418,6 +455,57 @@ def manage_admin():
    return ''


+def manage_metrics_account(ctx):
+    """Keep the service account metrics.service_account names, whose password is in METRICS_SECRET; the problem, or ''.
+
+    While metrics are enabled, setup owns the account: it adds it as a service account with a random password when
+    it is missing, and gives it a new random password, ending any lockout, when METRICS_SECRET is missing or does not
+    hold its password. A disabled account is left as it is. An account of that name that is not a service account is
+    left alone and is a problem.
+    """
+    if not vpnrouter.metrics_ready(ctx):
+        return ''
+    name = ctx['metrics_service_account']
+    try:
+        vpnrouter_users.check_name(name)
+        try:
+            password = METRICS_SECRET.read_text(encoding='utf-8').strip()
+        except OSError:
+            password = ''
+        with vpnrouter_users.session() as connection:
+            try:
+                current = vpnrouter_users.entry(connection, name)
+            except vpnrouter_users.Failure as failure:
+                if failure.status != 3:
+                    raise
+                current = None
+            if current is not None and not vpnrouter_users.service(current):
+                return f'metrics.service_account: {name} is a user, not a service account'
+            # An administrator who disabled the account meant it; its password is left as it is.
+            if current is not None and not vpnrouter_users.summary(current)['enabled']:
+                return ''
+            valid = False
+            if current is not None and password:
+                try:
+                    vpnrouter_users.login(name, password, None)
+                    valid = True
+                except vpnrouter_users.Failure:
+                    pass
+            if not valid:
+                password = secrets.token_urlsafe(32)
+                METRICS_SECRET.touch(mode=0o600)
+                METRICS_SECRET.chmod(0o600)
+                METRICS_SECRET.write_text(password + '\n', encoding='utf-8')
+                if current is None:
+                    vpnrouter_users.add(connection, name, password, {}, service=True)
+                else:
+                    vpnrouter_users.passwd(connection, name, password)
+                    vpnrouter_users.unlock(connection, name)
+    except (OSError, ldap.LDAPError, vpnrouter_users.Failure) as exc:
+        return f'the metrics service account cannot be kept: {exc}'
+    return ''
+
+
 def manage_openvpn(ctx, changed):
    """Run the OpenVPN server when it is configured, and stop it when it is not."""
    unit = 'openvpn-server@vpn-router'
@@ -433,6 +521,47 @@ def manage_openvpn(ctx, changed):
        run(['systemctl', 'restart', unit], check=False)


+def manage_caddy(ctx):
+    """Run Caddy, the HTTPS proxy of the web service, the Router Manager and the metrics service, while HTTPS is ready, and stop it when not.
+
+    CADDYFILE serves the web service on https.web_port, while the manager is installed the
+    manager on https.manager_port, and while metrics are enabled the metrics service on
+    metrics.https_port, all for wan.local_fqdn with a certificate from Let's Encrypt, and all
+    calling the service on its loopback address.
+    """
+    if not vpnrouter.https_ready(ctx):
+        vpnrouter.remove(CADDYFILE)
+        if unit_is_active(CADDY_UNIT):
+            run(['systemctl', 'disable', '--now', CADDY_UNIT], check=False)
+        return
+
+    try:
+        group = grp.getgrnam(CADDY_GROUP).gr_gid
+    except KeyError:
+        fail(f'the group {CADDY_GROUP} does not exist; is the caddy package installed?')
+    caddy_ctx = dict(ctx, manager_port=manager_port() if MANAGER.exists() else 0)
+    changed = vpnrouter.render(vpnrouter._jinja_env(), caddy_ctx, 'Caddyfile.j2', CADDYFILE, 0o640)
+    os.chown(CADDYFILE, 0, group)
+    if not unit_is_active(CADDY_UNIT):
+        run(['systemctl', 'enable', '--now', CADDY_UNIT], check=False)
+    elif changed:
+        run(['systemctl', 'reload', CADDY_UNIT], check=False)
+
+
+def manage_metrics(ctx):
+    """Run the metrics service while metrics are enabled, and stop it when not.
+
+    The service reads its settings itself, so it is restarted only to run the code of a new package version, which
+    every run of setup after an upgrade does.
+    """
+    unit = 'vpn-router-metrics.service'
+    if not vpnrouter.metrics_ready(ctx):
+        run(['systemctl', 'disable', '--now', unit], check=False)
+        return
+    run(['systemctl', 'enable', unit], check=False)
+    run(['systemctl', 'restart', unit], check=False)
+
+
 def run_platform_setup(cfg, ctx):
    """Let the platform module apply its own state, if it defines any."""
    module = vpnrouter.platform_module(cfg)
@@ -464,31 +593,37 @@ def refresh_web(cfg, ctx):
    the configuration without its secret options and the facts resolved from
    the system, which it cannot work out with the standard library alone. The
    file is readable by root only. The service follows a changed address or
-    port itself.
+    port itself. Secret options are left out at every level, so also from each
+    site-to-site connection.
    """
-    public = {
-        section: {option: value for option, value in options.items() if not SECRET_OPTION.search(option)}
-        for section, options in cfg.items()
-    }
+    def public(options):
+        return {option: public(value) if isinstance(value, dict) else value
+                for option, value in options.items()
+                if isinstance(value, dict) or not SECRET_OPTION.search(option)}
+
    WEB_STATE.parent.mkdir(parents=True, exist_ok=True)
    WEB_STATE.touch(mode=0o600)
    WEB_STATE.chmod(0o600)
    WEB_STATE.write_text(json.dumps({
-        'site_to_site': bool(vpnrouter.s2s_ready(ctx)),
+        'site_to_site': [connection['name'] for connection in ctx['connections'] if connection['ready']],
        'p2s': bool(vpnrouter.p2s_ready(ctx)),
        'wireguard': bool(vpnrouter.wg_ready(ctx)),
        'openvpn': bool(vpnrouter.openvpn_ready(ctx)),
-        'configuration': public,
+        'configuration': public(cfg),
        'network': {
            'external_interface': ctx['wan_iface'],
            'internal_interface': ctx['int_iface'],
            'external_addresses': ctx['local_addr_list'],
            'internal_address': ctx['int_addr'],
            'internal_gateway': ctx['int_gateway_ip'],
-            'local_identity': ctx['local_id'],
-            'remote_identity': ctx['remote_id'],
            'local_cidrs': ctx['local_cidr_list'],
-            'remote_cidrs': ctx['remote_cidr_list'],
+            'site_to_site': [{
+                'name': connection['name'],
+                'local_identity': connection['local_id'],
+                'remote_identity': connection['remote_id'],
+                'local_cidrs': connection['local_cidr_list'],
+                'remote_cidrs': connection['remote_cidr_list'],
+            } for connection in ctx['connections']],
        },
    }) + '\n', encoding='utf-8')

@@ -539,10 +674,10 @@ def main():
    if vpnrouter.routing_ready(ctx):
        apply_routes(ctx)

-    if ctx['local_id_mode'] == 'public_ip' and ctx['local_fqdn']:
+    if ctx['local_fqdn'] and any(connection['local_id_mode'] == 'public_ip' for connection in ctx['connections']):
        progress('running', 'public address')
        address = resolve_public_ip(ctx['local_fqdn'])
-        ctx, more = vpnrouter.configure(cfg, local_id_override=address)
+        ctx, more = vpnrouter.configure(cfg, public_ip=address)
        changed |= more

    progress('running', 'WireGuard keys')
@@ -574,8 +709,14 @@ def main():
        failed_step = 'Router Manager admin'
        progress('running', failed_step)
        problem = manage_admin()
+    if not problem:
+        failed_step = 'metrics service account'
+        progress('running', failed_step)
+        problem = manage_metrics_account(ctx)
    progress('running', 'OpenVPN')
    manage_openvpn(ctx, changed)
+    progress('running', 'HTTPS proxy')
+    manage_caddy(ctx)

    if 'resolved' in changed:
        progress('running', 'resolver')
@@ -587,6 +728,8 @@ def main():
    refresh_docker_rules()
    progress('running', 'web service state')
    refresh_web(cfg, ctx)
+    progress('running', 'metrics service')
+    manage_metrics(ctx)
    if problem:
        progress('failed', failed_step, problem)
        print(f'vpn-router: error: {problem}', file=sys.stderr)
@@ -4,6 +4,8 @@ Everything derivable from the configuration file alone, with no running
 network required. Used by both 'configure' and 'setup'.
 """

+import contextlib
+import fcntl
 import ipaddress
 import json
 import os
@@ -12,6 +14,8 @@ import re
 import shutil
 import subprocess
 import sys
+import tempfile
+import urllib.parse

 import jinja2

@@ -21,15 +25,16 @@ if str(LIB_DIR) not in sys.path:

 import vpnrouter_ldap
 import vpnrouter_platforms
-from vpnrouter_net import DEFAULT_LISTEN, LISTEN_CHOICES, ConfigError, detect_interfaces, interface_addresses, ip_output
+from vpnrouter_net import DEFAULT_LISTEN, LISTEN_CHOICES, LOOPBACK, ConfigError, detect_interfaces, interface_addresses, ip_output

 CONFIG_FILE  = pathlib.Path('/etc/vpn-router/vpn-router.json')
+CONFIG_LOCK  = pathlib.Path('/run/vpn-router/config.lock')
 TEMPLATE_DIR = pathlib.Path('/usr/share/vpn-router/templates')
 PKI_DIR      = pathlib.Path('/etc/vpn-router/pki')
 SIMPLE_CA    = LIB_DIR / 'simple-ca'

 SWANCTL_CONF_D = pathlib.Path('/etc/swanctl/conf.d')
-REMOTE_SITE    = SWANCTL_CONF_D / 'remote-site.conf'
+SITE_TO_SITE   = SWANCTL_CONF_D / 'site-to-site.conf'
 ROAD_WARRIOR   = SWANCTL_CONF_D / 'road-warrior.conf'
 P2S_FORWARDER  = pathlib.Path('/etc/systemd/resolved.conf.d/p2s-forwarder.conf')
 WG_CONF        = pathlib.Path('/etc/wireguard/wg0.conf')
@@ -47,16 +52,43 @@ TRUST_ANCHOR   = pathlib.Path('/usr/local/share/ca-certificates/vpn-router-ca.cr
 SCHEMA = {
    'general':    {'platform': 'none', 'mode': 'manual'},
    'interfaces': {'external': '', 'internal': ''},
-    'wan':        {'local_fqdn': '', 'local_id_mode': 'fqdn'},
+    'wan':        {'local_fqdn': ''},
    'local':      {'cidrs': [], 'int_addr': '', 'int_gateway_ip': ''},
-    'remote':     {'addrs': [], 'id': '', 'cidrs': [], 'psk': '', 'psk_file': ''},
+    'site_to_site': {},
    'p2s':        {'enabled': False, 'address_pool': '', 'ca_name': 'VPN Router CA'},
    'wireguard':  {'enabled': False, 'address': '', 'listen_port': 51820},
    'openvpn':    {'enabled': False, 'address_pool': '', 'port': 1194, 'protocol': 'udp'},
    'docker':     {'mode': 'auto', 'exposed_ports': []},
-    'web':        {'enabled': True, 'listen': DEFAULT_LISTEN, 'port': 7081, 'database': '', 'trusted_proxies': []},
+    'web':        {'enabled': True, 'listen': DEFAULT_LISTEN, 'port': 7081, 'database': '', 'trusted_proxies': [],
+                   'status_content': 'basic'},
+    'https':      {'enabled': True, 'email': '', 'web_port': 7444, 'manager_port': 7443},
+    'metrics':    {'enabled': True, 'listen': 'internal', 'port': 9464, 'https_port': 9465, 'service_account': 'metrics',
+                   'otlp_endpoint': '', 'otlp_username': '', 'otlp_password': '',
+                   'keep_details': '24 hours', 'keep_hourly': '1 month', 'keep_daily': '3 months',
+                   'keep_monthly': '1 year', 'keep_yearly': '10 years'},
 }

+#: site_to_site maps a connection name to its settings: option -> default, the type of the default being the required type.
+CONNECTION = {'addrs': [], 'id': '', 'cidrs': [], 'local_cidrs': [], 'local_id_mode': 'fqdn', 'psk': '', 'psk_file': ''}
+
+#: The name of a site_to_site connection, which also names its swanctl connection, child and secret.
+CONNECTION_NAME = re.compile(r'^[a-z][a-z0-9-]{0,30}$')
+
+#: The site_to_site connection the install answers fill.
+FIRST_CONNECTION = 'remote-site'
+
+#: The retention settings of the metrics, from the details to the yearly summaries.
+METRICS_KEEP = ('keep_details', 'keep_hourly', 'keep_daily', 'keep_monthly', 'keep_yearly')
+
+#: A retention period as PostgreSQL reads an interval: a count and a unit.
+METRICS_INTERVAL = re.compile(r'^[1-9]\d{0,4} (hour|day|month|year)s?$')
+
+#: The port of Let's Encrypt's HTTP challenge, which Caddy answers while HTTPS is on.
+ACME_HTTP_PORT = 80
+
+#: What / and /status of the web service show, web.status_content, from the least to the most.
+STATUS_CONTENTS = ('basic', 'standard', 'full')
+
 DOCKER_MODES = ('auto', 'on', 'off')

 OPENVPN_PROTOCOLS = ('udp', 'tcp')
@@ -74,7 +106,7 @@ DOCKER_PORT = re.compile(r'^\d{1,5}(:\d{1,5})?$')
 DOCKER_PORT_LIMIT = 15

 TYPE_NAMES = {str: 'a string', list: 'a list of strings', bool: 'a boolean',
-              int: 'an integer'}
+              int: 'an integer', dict: 'an object'}

 ID_MODES = ('fqdn', 'public_ip', 'internal_ip')

@@ -99,29 +131,76 @@ def fail(message):
    sys.exit(f'vpn-router: error: {message}')


-def load_config(path=None):
-    """Read the configuration, filling in defaults for anything absent.
+def read_settings(path=None):
+    """The settings in the configuration file, without the defaults; {} when the file does not exist.

-    The result maps section -> option -> value. Sections and options not in
-    SCHEMA are kept so that validate() can report them.
+    Raises ConfigError when the file is not JSON or not an object of sections.
+    """
+    path = pathlib.Path(path) if path else CONFIG_FILE
+    try:
+        data = json.loads(path.read_text(encoding='utf-8'))
+    except FileNotFoundError:
+        return {}
+    except ValueError as exc:
+        raise ConfigError(f'cannot parse {path}: {exc}')
+    if not isinstance(data, dict):
+        raise ConfigError(f'cannot parse {path}: the top level is not an object')
+    for section, options in data.items():
+        if not isinstance(options, dict):
+            raise ConfigError(f'cannot parse {path}: {section} is not an object')
+    return data
+
+
+def with_defaults(data):
+    """The configuration of the settings of read_settings, with the defaults for anything absent.
+
+    The result maps section -> option -> value, and site_to_site maps each connection name to
+    its settings filled from CONNECTION. Sections, options and connections that are not
+    objects are kept so that validate() can report them.
+    """
+    cfg = {section: dict(options) for section, options in SCHEMA.items()}
+    for section, options in data.items():
+        cfg.setdefault(section, {}).update(options)
+    cfg['site_to_site'] = {name: {**CONNECTION, **options} if isinstance(options, dict) else options
+                           for name, options in cfg['site_to_site'].items()}
+    return cfg
+
+
+def load_config(path=None):
+    """Read the configuration, filling in defaults for anything absent (see with_defaults).

    The path is resolved when called, not when this function is defined, so
    CONFIG_FILE stays overridable.
    """
-    path = pathlib.Path(path) if path else CONFIG_FILE
-    cfg = {section: dict(options) for section, options in SCHEMA.items()}
-    if path.exists():
-        try:
-            data = json.loads(path.read_text(encoding='utf-8'))
-        except ValueError as exc:
-            fail(f'cannot parse {path}: {exc}')
-        if not isinstance(data, dict):
-            fail(f'cannot parse {path}: the top level is not an object')
-        for section, options in data.items():
-            if not isinstance(options, dict):
-                fail(f'cannot parse {path}: {section} is not an object')
-            cfg.setdefault(section, {}).update(options)
-    return cfg
+    try:
+        return with_defaults(read_settings(path))
+    except ConfigError as exc:
+        fail(str(exc))
+
+
+@contextlib.contextmanager
+def config_lock():
+    """Hold the lock of the configuration file from reading it to writing it with save_config."""
+    CONFIG_LOCK.parent.mkdir(parents=True, exist_ok=True)
+    with open(CONFIG_LOCK, 'a', encoding='utf-8') as handle:
+        fcntl.flock(handle, fcntl.LOCK_EX)
+        yield
+
+
+def save_config(data):
+    """Write the settings to the configuration file, indented, with mode 0600, replacing it in one step.
+
+    The caller holds config_lock.
+    """
+    descriptor, name = tempfile.mkstemp(dir=CONFIG_FILE.parent, prefix='.vpn-router.json.')
+    try:
+        with os.fdopen(descriptor, 'w', encoding='utf-8') as handle:
+            handle.write(json.dumps(data, indent=2) + '\n')
+        os.chmod(name, 0o600)
+        os.replace(name, CONFIG_FILE)
+    except OSError:
+        os.unlink(name)
+        raise


 def _split_list(value):
@@ -133,23 +212,37 @@ def _get(cfg, section, option):
    return value.strip() if isinstance(value, str) else value


+def _clean(values):
+    return [item.strip() for item in values if item.strip()]
+
+
 def _get_list(cfg, section, option):
-    return [item.strip() for item in cfg[section][option] if item.strip()]
+    return _clean(cfg[section][option])
+
+
+def _check_options(options, defaults, prefix):
+    for option, value in options.items():
+        if option not in defaults:
+            raise ConfigError(f'{prefix}.{option}: unknown setting')
+        expected = type(defaults[option])
+        if type(value) is not expected or (
+                expected is list and
+                not all(isinstance(item, str) for item in value)):
+            raise ConfigError(
+                f'{prefix}.{option} must be {TYPE_NAMES[expected]}')


 def _check_types(cfg):
    for section, options in cfg.items():
        if section not in SCHEMA:
            raise ConfigError(f'{section}: unknown section')
-        for option, value in options.items():
-            if option not in SCHEMA[section]:
-                raise ConfigError(f'{section}.{option}: unknown setting')
-            expected = type(SCHEMA[section][option])
-            if type(value) is not expected or (
-                    expected is list and
-                    not all(isinstance(item, str) for item in value)):
-                raise ConfigError(
-                    f'{section}.{option} must be {TYPE_NAMES[expected]}')
+        if section != 'site_to_site':
+            _check_options(options, SCHEMA[section], section)
+            continue
+        for name, connection in options.items():
+            if not isinstance(connection, dict):
+                raise ConfigError(f'site_to_site.{name} must be {TYPE_NAMES[dict]}')
+            _check_options(connection, CONNECTION, f'site_to_site.{name}')


 def _check_networks(values, name):
@@ -201,19 +294,28 @@ def validate(cfg):
                raise ConfigError(
                    f'{section}.{option} is required in mode {mode or "manual"}')

-    for section, option in (('wan', 'local_fqdn'), ('remote', 'id')):
-        if str(_get(cfg, section, option)).startswith('@'):
+    identities = [('wan.local_fqdn', _get(cfg, 'wan', 'local_fqdn'))]
+    for name, connection in cfg['site_to_site'].items():
+        prefix = f'site_to_site.{name}'
+        if not CONNECTION_NAME.match(name):
            raise ConfigError(
-                f'{section}.{option}: remove the leading @; strongSwan reads an '
+                f'{prefix}: a connection name starts with a lowercase letter and has at most 31 '
+                'lowercase letters, digits and hyphens')
+        identities.append((f'{prefix}.id', connection['id'].strip()))
+        id_mode = connection['local_id_mode'].strip()
+        if id_mode and id_mode not in ID_MODES:
+            raise ConfigError(
+                f'{prefix}.local_id_mode: {id_mode!r} is not one of {", ".join(ID_MODES)}')
+        _check_networks(_clean(connection['cidrs']), f'{prefix}.cidrs')
+        _check_networks(_clean(connection['local_cidrs']), f'{prefix}.local_cidrs')
+
+    for option, value in identities:
+        if value.startswith('@'):
+            raise ConfigError(
+                f'{option}: remove the leading @; strongSwan reads an '
                'address as an IP identity and a name as an FQDN')

-    id_mode = _get(cfg, 'wan', 'local_id_mode')
-    if id_mode and id_mode not in ID_MODES:
-        raise ConfigError(
-            f'wan.local_id_mode: {id_mode!r} is not one of {", ".join(ID_MODES)}')
-
    _check_networks(_get_list(cfg, 'local', 'cidrs'), 'local.cidrs')
-    _check_networks(_get_list(cfg, 'remote', 'cidrs'), 'remote.cidrs')
    pool = _get(cfg, 'p2s', 'address_pool')
    _check_networks([pool] if pool else [], 'p2s.address_pool')
    openvpn_pool = _get(cfg, 'openvpn', 'address_pool')
@@ -264,9 +366,52 @@ def validate(cfg):
        raise ConfigError(
            f'web.listen: {web_listen!r} is not one of {", ".join(LISTEN_CHOICES)}')

+    status_content = _get(cfg, 'web', 'status_content')
+    if status_content not in STATUS_CONTENTS:
+        raise ConfigError(
+            f'web.status_content: {status_content!r} is not one of {", ".join(STATUS_CONTENTS)}')
+
+    https_ports = []
+    for option in ('web_port', 'manager_port'):
+        port = _get(cfg, 'https', option)
+        if isinstance(port, bool) or not isinstance(port, int) or not 1 <= port <= 65535:
+            raise ConfigError(f'https.{option}: {port!r} is not a valid port')
+        if port == ACME_HTTP_PORT:
+            raise ConfigError(f'https.{option}: {port} is the port of the HTTP challenge')
+        https_ports.append(port)
+    if https_ports[0] == https_ports[1]:
+        raise ConfigError('https.web_port and https.manager_port must differ')
+
    for item in _get_list(cfg, 'web', 'trusted_proxies'):
        _check_address(item, 'web.trusted_proxies')

+    taken = {web_port: 'web.port', ACME_HTTP_PORT: 'the HTTP challenge',
+             https_ports[0]: 'https.web_port', https_ports[1]: 'https.manager_port'}
+    for option in ('port', 'https_port'):
+        port = _get(cfg, 'metrics', option)
+        if isinstance(port, bool) or not isinstance(port, int) or not 1 <= port <= 65535:
+            raise ConfigError(f'metrics.{option}: {port!r} is not a valid port')
+        if port in taken:
+            raise ConfigError(f'metrics.{option}: {port} is the port of {taken[port]}')
+        taken[port] = f'metrics.{option}'
+
+    metrics_listen = _get(cfg, 'metrics', 'listen')
+    if metrics_listen not in LISTEN_CHOICES:
+        raise ConfigError(
+            f'metrics.listen: {metrics_listen!r} is not one of {", ".join(LISTEN_CHOICES)}')
+
+    endpoint = _get(cfg, 'metrics', 'otlp_endpoint')
+    if endpoint and urllib.parse.urlsplit(endpoint).scheme not in ('http', 'https'):
+        raise ConfigError(f'metrics.otlp_endpoint: {endpoint!r} is not an http or https URL')
+    if bool(_get(cfg, 'metrics', 'otlp_username')) != bool(_get(cfg, 'metrics', 'otlp_password')):
+        raise ConfigError('metrics.otlp_username and metrics.otlp_password are given together')
+
+    for option in METRICS_KEEP:
+        keep = _get(cfg, 'metrics', option)
+        if not METRICS_INTERVAL.match(keep):
+            raise ConfigError(
+                f'metrics.{option}: {keep!r} is not a count and a unit, such as "24 hours" or "3 months"')
+
    docker_mode = _get(cfg, 'docker', 'mode')
    if docker_mode not in DOCKER_MODES:
        raise ConfigError(
@@ -280,21 +425,28 @@ def validate(cfg):
            raise ConfigError(
                f'docker.exposed_ports: {item!r} is not a port or a port range')
        weight += 2 if ':' in item else 1
+        first, _, last = item.partition(':')
+        if _get(cfg, 'https', 'enabled'):
+            for port in (ACME_HTTP_PORT, *https_ports):
+                if int(first) <= port <= int(last or first):
+                    raise ConfigError(
+                        f'docker.exposed_ports: {item!r} takes port {port}, which Caddy serves while '
+                        'https.enabled is true')
    if weight > DOCKER_PORT_LIMIT:
        raise ConfigError(
            f'docker.exposed_ports: at most {DOCKER_PORT_LIMIT} ports are allowed, '
            'a range counting as two')


-def resolve_psk(cfg):
-    """Return the pre-shared key, or '' when none is configured."""
-    psk_file = _get(cfg, 'remote', 'psk_file')
+def resolve_psk(connection, name):
+    """Return the pre-shared key of the site_to_site connection: psk_file wins, else psk; '' when none is configured."""
+    psk_file = connection['psk_file'].strip()
    if psk_file:
        path = pathlib.Path(psk_file)
        if not path.is_file():
-            raise ConfigError(f'remote.psk_file: {psk_file} does not exist')
+            raise ConfigError(f'site_to_site.{name}.psk_file: {psk_file} does not exist')
        return path.read_text(encoding='utf-8').strip()
-    return cfg['remote']['psk']
+    return connection['psk']


 def platform_module(cfg):
@@ -378,29 +530,43 @@ def resolve_interfaces(cfg):
    return ext_iface, int_iface, local_addrs, int_addr, gateway


-def build_context(cfg, local_id_override=None):
-    """Assemble the template context from the configuration."""
+def build_context(cfg, public_ip=None):
+    """Assemble the template context from the configuration.
+
+    public_ip is the address wan.local_fqdn resolves to, the local identity of the
+    site_to_site connections in mode public_ip; setup resolves it once the network is up and
+    renders again, and without it such a connection is not ready.
+    """
    extras = vpnrouter_platforms.context(platform_module(cfg))

    ext_iface, int_iface, local_addrs, int_addr, gateway = resolve_interfaces(cfg)

    local_fqdn   = _get(cfg, 'wan', 'local_fqdn')
-    id_mode      = _get(cfg, 'wan', 'local_id_mode') or 'fqdn'
    local_cidrs  = _get_list(cfg, 'local', 'cidrs')
-    remote_cidrs = _get_list(cfg, 'remote', 'cidrs')
    openvpn_pool = _get(cfg, 'openvpn', 'address_pool')
    openvpn_network = ipaddress.ip_network(openvpn_pool) if openvpn_pool else None
+    identities = {'fqdn': local_fqdn, 'public_ip': public_ip or '', 'internal_ip': int_addr}

-    if local_id_override:
-        local_id = local_id_override
-    elif id_mode == 'fqdn':
-        local_id = local_fqdn
-    elif id_mode == 'internal_ip':
-        local_id = int_addr
-    else:
-        # public_ip is resolved once the network is up, and the caller then
-        # re-renders with local_id_override set.
-        local_id = ''
+    connections = []
+    for name, connection in cfg['site_to_site'].items():
+        id_mode = connection['local_id_mode'].strip() or 'fqdn'
+        remote_cidrs = _clean(connection['cidrs'])
+        connection_cidrs = _clean(connection['local_cidrs'])
+        entry = {
+            'name':             name,
+            'remote_addrs':     ', '.join(_clean(connection['addrs'])),
+            'remote_id':        connection['id'].strip(),
+            'remote_cidrs':     ', '.join(remote_cidrs),
+            'remote_cidr_list': remote_cidrs,
+            'local_ts':         _join(connection_cidrs, _split_list(extras['EXTRA_LOCAL_TS'])),
+            'local_cidr_list':  connection_cidrs,
+            'local_id_mode':    id_mode,
+            'local_id':         identities.get(id_mode, ''),
+            'psk':              resolve_psk(connection, name),
+        }
+        entry['ready'] = bool(local_addrs and connection_cidrs and all(
+            entry[key] for key in ('remote_addrs', 'remote_id', 'remote_cidrs', 'local_id', 'psk')))
+        connections.append(entry)

    return {
        'platform':        _get(cfg, 'general', 'platform') or PLATFORM_NONE,
@@ -410,18 +576,12 @@ def build_context(cfg, local_id_override=None):
        'local_addrs':     ', '.join(local_addrs),
        'local_addr_list': local_addrs,
        'local_fqdn':      local_fqdn,
-        'local_id_mode':   id_mode,
-        'local_id':        local_id,
        'local_cidrs':     ', '.join(local_cidrs),
        'local_cidr_list': local_cidrs,
        'local_ts':        _join(local_cidrs, _split_list(extras['EXTRA_LOCAL_TS'])),
        'int_addr':        int_addr,
        'int_gateway_ip':  gateway,
-        'remote_addrs':    ', '.join(_get_list(cfg, 'remote', 'addrs')),
-        'remote_id':       _get(cfg, 'remote', 'id'),
-        'remote_cidrs':    ', '.join(remote_cidrs),
-        'remote_cidr_list': remote_cidrs,
-        'psk':             resolve_psk(cfg),
+        'connections':     connections,
        'p2s_enabled':     _get(cfg, 'p2s', 'enabled'),
        'p2s_address_pool': _get(cfg, 'p2s', 'address_pool'),
        'p2s_ca_name':     _get(cfg, 'p2s', 'ca_name'),
@@ -448,15 +608,21 @@ def build_context(cfg, local_id_override=None):
        'ldap_users':      vpnrouter_ldap.USERS,
        'web_enabled':     _get(cfg, 'web', 'enabled'),
        'web_port':        _get(cfg, 'web', 'port'),
+        'https_enabled':   _get(cfg, 'https', 'enabled'),
+        'https_email':     _get(cfg, 'https', 'email'),
+        'https_web_port':  _get(cfg, 'https', 'web_port'),
+        'https_manager_port': _get(cfg, 'https', 'manager_port'),
+        'metrics_enabled': _get(cfg, 'metrics', 'enabled'),
+        'metrics_port':    _get(cfg, 'metrics', 'port'),
+        'metrics_https_port': _get(cfg, 'metrics', 'https_port'),
+        'metrics_service_account': _get(cfg, 'metrics', 'service_account'),
+        'loopback':        LOOPBACK,
    }


 def s2s_ready(ctx):
-    return all([
-        ctx['local_addrs'], ctx['local_fqdn'], ctx['local_cidrs'],
-        ctx['remote_addrs'], ctx['remote_id'], ctx['remote_cidrs'],
-        ctx['psk'], ctx['local_id'],
-    ])
+    """True when any site_to_site connection is ready."""
+    return any(connection['ready'] for connection in ctx['connections'])


 def routing_ready(ctx):
@@ -477,6 +643,16 @@ def openvpn_ready(ctx):
    return bool(ctx['openvpn_enabled'] and ctx['openvpn_pool'] and ctx['local_fqdn'])


+def https_ready(ctx):
+    """Caddy serves HTTPS once it is enabled and wan.local_fqdn names the certificate."""
+    return bool(ctx['https_enabled'] and ctx['local_fqdn'])
+
+
+def metrics_ready(ctx):
+    """The metrics service collects, keeps and serves the metrics while metrics.enabled is true."""
+    return bool(ctx['metrics_enabled'])
+
+
 def _jinja_env():
    return jinja2.Environment(
        loader=jinja2.FileSystemLoader(str(TEMPLATE_DIR)),
@@ -611,7 +787,7 @@ def distribute_pki(ctx):
    return changed


-def configure(cfg=None, local_id_override=None):
+def configure(cfg=None, public_ip=None):
    """Render configuration files and provision PKI.

    Returns (ctx, changed) where changed is a set naming what needs reloading:
@@ -627,7 +803,7 @@ def configure(cfg=None, local_id_override=None):

    try:
        validate(cfg)
-        ctx = build_context(cfg, local_id_override=local_id_override)
+        ctx = build_context(cfg, public_ip=public_ip)
    except ConfigError as exc:
        fail(str(exc))

@@ -640,9 +816,9 @@ def configure(cfg=None, local_id_override=None):
    env = _jinja_env()

    if s2s_ready(ctx):
-        if render(env, ctx, 'remote-site.conf.j2', REMOTE_SITE, 0o600):
+        if render(env, ctx, 'site-to-site.conf.j2', SITE_TO_SITE, 0o600):
            changed.add('swanctl')
-    elif remove(REMOTE_SITE):
+    elif remove(SITE_TO_SITE):
        changed.add('swanctl')

    if p2s_ready(ctx):
@@ -53,7 +53,7 @@ OVERLAYS = ('ppolicy', 'otp')
 #: The package's own schema, under an OID of the UUID arc 2.25 (ITU-T X.667): attribute types
 #: under .1 and object classes under .2. vpnRouterAccount, auxiliary, adds properties of the
 #: package to a user of either kind: mail, for a Manager-only account, and vpnRouterScope,
-#: authorization scopes that nothing reads yet.
+#: authorization scopes, of which service marks a service account.
 SCHEMA_OID = '2.25.98477352595735834532404256531620013001'
 SCHEMA_NAME = 'vpn-router'
 SCHEMA_ATTRIBUTE_TYPES = (
@@ -0,0 +1,185 @@
+"""The metrics of the router in PostgreSQL, for the metrics service and the web service.
+
+The metrics service writes one detail row per minute to the four detail tables, of TABLES:
+metrics_system (CPU, memory, disk and load averages), metrics_network (bytes per second
+received and sent per interface), metrics_vpn (clients per kind) and metrics_site_to_site (per
+site-to-site connection: up, 1 or 0, bytes and packets per second received and sent, and the
+seconds its IKE SA has been up). Each detail table has four
+summary tables, of LEVELS: <table>_hourly from the details, <table>_daily from the hourly,
+<table>_monthly from the daily and <table>_yearly from the monthly rows. A summary row has the
+start of its period, in UTC, and the average and the maximum of each value over the period: of
+the details for the hourly rows, else the average of the averages and the maximum of the maxima
+below. A period is summarized once it is complete; summarize() catches up every complete period
+after the last summarized one, so a stopped service loses no summary of what was written.
+
+collect_garbage() deletes the rows older than the retention of their level, metrics.keep_*;
+the service runs it on start and once a day. history() answers the views of the Metrics tab.
+
+The tables are in the database of the refresh tokens (vpnrouter_auth.connection_string) and are
+created when missing. Every failure of the database raises DatabaseError.
+"""
+
+import contextlib
+
+import psycopg
+
+import vpnrouter_auth
+
+#: The detail tables: their key columns besides time, and their value columns.
+TABLES = {
+    'metrics_system': ((), ('cpu', 'memory_used', 'memory_total', 'disk_free', 'disk_total', 'load1', 'load5', 'load15')),
+    'metrics_network': (('interface',), ('rx', 'tx')),
+    'metrics_vpn': (('kind',), ('clients',)),
+    'metrics_site_to_site': (('connection',), ('up', 'rx', 'tx', 'packets_rx', 'packets_tx', 'uptime')),
+}
+
+#: The summary levels, from the finest: the suffix of the tables, the period of date_trunc and the retention setting.
+LEVELS = (
+    ('hourly', 'hour', 'keep_hourly'),
+    ('daily', 'day', 'keep_daily'),
+    ('monthly', 'month', 'keep_monthly'),
+    ('yearly', 'year', 'keep_yearly'),
+)
+
+#: The kinds of VPN clients of metrics_vpn.
+VPN_KINDS = ('p2s', 'openvpn', 'wireguard')
+
+#: The views of history(): the summary level read (None: the details), the bucket and the span.
+RANGES = {
+    'hour': (None, '1 minute', '1 hour'),
+    'day': (None, '10 minutes', '1 day'),
+    'month': ('hourly', '6 hours', '1 month'),
+    'year': ('monthly', '1 month', '1 year'),
+}
+
+
+class DatabaseError(Exception):
+    """The metrics database failed."""
+
+
+def schema():
+    """The statements that create the detail and the summary tables."""
+    statements = []
+    for table, (keys, values) in TABLES.items():
+        key_columns = ''.join(f', {key} text NOT NULL' for key in keys)
+        primary = ', '.join(('time', *keys))
+        detail = ''.join(f', {value} double precision' for value in values)
+        statements.append(f'CREATE TABLE IF NOT EXISTS {table} (time timestamptz NOT NULL{key_columns}{detail}, '
+                          f'PRIMARY KEY ({primary}))')
+        summary = ''.join(f', {value}_avg double precision, {value}_max double precision' for value in values)
+        for suffix, _, _ in LEVELS:
+            statements.append(f'CREATE TABLE IF NOT EXISTS {table}_{suffix} (time timestamptz NOT NULL{key_columns}{summary}, '
+                              f'PRIMARY KEY ({primary}))')
+    return statements
+
+
+@contextlib.contextmanager
+def database(cfg):
+    """A connection to the metrics database, with its tables, closed at the end; DatabaseError on any failure."""
+    try:
+        with psycopg.connect(vpnrouter_auth.connection_string(cfg), autocommit=True) as connection:
+            for statement in schema():
+                connection.execute(statement)
+            yield connection
+    except (psycopg.Error, OSError) as exc:
+        raise DatabaseError(f'the metrics database failed: {exc}') from exc
+
+
+def write(connection, system, network, vpn, site_to_site):
+    """Write a sample as the detail rows of the current minute.
+
+    system maps the values of metrics_system to numbers; network maps an interface to its rx and
+    tx; vpn maps a kind of VPN_KINDS to its clients; site_to_site maps a connection to the values
+    of metrics_site_to_site. A value that is None is written as NULL.
+    """
+    with connection.transaction():
+        minute = connection.execute("SELECT date_trunc('minute', now(), 'UTC')").fetchone()[0]
+        names = TABLES['metrics_system'][1]
+        connection.execute(f"INSERT INTO metrics_system (time, {', '.join(names)}) "
+                           f"VALUES (%s{', %s' * len(names)}) ON CONFLICT DO NOTHING",
+                           (minute, *(system.get(name) for name in names)))
+        for interface, (rx, tx) in network.items():
+            connection.execute('INSERT INTO metrics_network (time, interface, rx, tx) VALUES (%s, %s, %s, %s) '
+                               'ON CONFLICT DO NOTHING', (minute, interface, rx, tx))
+        for kind, clients in vpn.items():
+            connection.execute('INSERT INTO metrics_vpn (time, kind, clients) VALUES (%s, %s, %s) ON CONFLICT DO NOTHING',
+                               (minute, kind, clients))
+        names = TABLES['metrics_site_to_site'][1]
+        for name, values in site_to_site.items():
+            connection.execute(f"INSERT INTO metrics_site_to_site (time, connection, {', '.join(names)}) "
+                               f"VALUES (%s, %s{', %s' * len(names)}) ON CONFLICT DO NOTHING",
+                               (minute, name, *(values.get(value) for value in names)))
+
+
+def summarize(connection, level):
+    """Summarize the complete periods of a level of LEVELS that are not summarized yet, for every detail table."""
+    index = [suffix for suffix, _, _ in LEVELS].index(level)
+    _, period, _ = LEVELS[index]
+    for table, (keys, values) in TABLES.items():
+        target = f'{table}_{level}'
+        source = table if index == 0 else f'{table}_{LEVELS[index - 1][0]}'
+        if index == 0:
+            aggregates = ', '.join(f'avg({value}), max({value})' for value in values)
+        else:
+            aggregates = ', '.join(f'avg({value}_avg), max({value}_max)' for value in values)
+        columns = ', '.join(('time', *keys, *(f'{value}_{kind}' for value in values for kind in ('avg', 'max'))))
+        groups = ''.join(f', {key}' for key in keys)
+        connection.execute(
+            f"INSERT INTO {target} ({columns}) "
+            f"SELECT date_trunc('{period}', time, 'UTC') AS period{groups}, {aggregates} FROM {source} "
+            f"WHERE time < date_trunc('{period}', now(), 'UTC') "
+            f"AND time >= coalesce((SELECT max(time) FROM {target}) + interval '1 {period}', '-infinity') "
+            f"GROUP BY period{groups} ON CONFLICT DO NOTHING")
+
+
+def collect_garbage(connection, cfg):
+    """Delete the rows older than the retention of their level: metrics.keep_details, keep_hourly and so on."""
+    metrics = cfg['metrics']
+    for table in TABLES:
+        connection.execute(f'DELETE FROM {table} WHERE time < now() - %s::interval', (metrics['keep_details'],))
+        for suffix, _, keep in LEVELS:
+            connection.execute(f'DELETE FROM {table}_{suffix} WHERE time < now() - %s::interval', (metrics[keep],))
+
+
+def history(connection, view):
+    """The points of a view of RANGES, oldest first, each with the start of its bucket in Unix seconds.
+
+    A point has the average and the maximum of each value of metrics_system, network, which maps
+    each interface to its rx and tx, clients, which maps each kind of VPN client to its clients,
+    and site_to_site, which maps each site-to-site connection to the values of
+    metrics_site_to_site; a value without data is None.
+    """
+    level, bucket, span = RANGES[view]
+
+    def rows(table):
+        keys, values = TABLES[table]
+        source = table if level is None else f'{table}_{level}'
+        if level is None:
+            aggregates = ', '.join(f'avg({value}), max({value})' for value in values)
+        else:
+            aggregates = ', '.join(f'avg({value}_avg), max({value}_max)' for value in values)
+        start = (f"date_bin('{bucket}', time, timestamptz '2000-01-01 00:00:00+00')" if view != 'year'
+                 else "date_trunc('month', time, 'UTC')")
+        groups = ''.join(f', {key}' for key in keys)
+        return connection.execute(
+            f"SELECT extract(epoch FROM {start})::bigint AS bucket{groups}, {aggregates} FROM {source} "
+            f"WHERE time >= now() - interval '{span}' GROUP BY bucket{groups} ORDER BY bucket").fetchall()
+
+    def pairs(row, values):
+        return {value: {'avg': row[2 * index], 'max': row[2 * index + 1]} for index, value in enumerate(values)}
+
+    points = {}
+
+    def point(start):
+        return points.setdefault(start, {'time': start, 'network': {}, 'clients': {}, 'site_to_site': {}})
+
+    for row in rows('metrics_system'):
+        point(row[0]).update(pairs(row[1:], TABLES['metrics_system'][1]))
+    for row in rows('metrics_network'):
+        point(row[0])['network'][row[1]] = pairs(row[2:], TABLES['metrics_network'][1])
+    for row in rows('metrics_vpn'):
+        point(row[0])['clients'][row[1]] = pairs(row[2:], TABLES['metrics_vpn'][1])['clients']
+    for row in rows('metrics_site_to_site'):
+        point(row[0])['site_to_site'][row[1]] = pairs(row[2:], TABLES['metrics_site_to_site'][1])
+    empty = {value: {'avg': None, 'max': None} for value in TABLES['metrics_system'][1]}
+    return {'range': view, 'bucket': bucket, 'points': [{**empty, **points[start]} for start in sorted(points)]}
@@ -13,6 +13,9 @@ LISTEN_CHOICES = ('internal', 'external', 'both')
 #: The interfaces a service listens on when it is not set.
 DEFAULT_LISTEN = 'both'

+#: The address every service also listens on, where the HTTPS proxy calls it.
+LOOPBACK = '127.0.0.1'
+

 class ConfigError(Exception):
    """A setting is present but malformed."""
@@ -140,7 +143,7 @@ def listen_addresses(configuration, choice):
    """The addresses a service listens on for choice of LISTEN_CHOICES, from vpn-router.json read as configuration.

    The internal address comes first; an address not known yet is left out. A choice that is not
-    one of LISTEN_CHOICES is DEFAULT_LISTEN.
+    one of LISTEN_CHOICES is DEFAULT_LISTEN. LOOPBACK is not among them; web_listen adds it.
    """
    if choice not in LISTEN_CHOICES:
        choice = DEFAULT_LISTEN
@@ -157,9 +160,9 @@ def listen_addresses(configuration, choice):
 def web_listen(configuration, default_port):
    """Where the web service listens, from vpn-router.json read as configuration, as ([(address, port), ...], '').

-    The addresses are those of the interfaces web.listen names (listen_addresses), the port
-    web.port, else default_port. While web.enabled is false or no address is known, the answer
-    is ([], the reason).
+    The addresses are those of the interfaces web.listen names (listen_addresses), then
+    LOOPBACK, the port web.port, else default_port. While web.enabled is false or no address of
+    an interface is known, the answer is ([], the reason).
    """
    web = _section(configuration, 'web')
    if web.get('enabled', True) is False:
@@ -170,4 +173,4 @@ def web_listen(configuration, default_port):
    addresses = listen_addresses(configuration, web.get('listen', DEFAULT_LISTEN))
    if not addresses:
        return [], 'the addresses to listen on are not known yet'
-    return [(address, port) for address in addresses], ''
+    return [(address, port) for address in [*addresses, LOOPBACK]], ''
@@ -0,0 +1,145 @@
+"""What the router's VPN systems report, for the web service and the metrics service.
+
+Each reader asks the running system once and answers None when it cannot be asked: swanctl for
+the IKE SAs and the state and traffic of the site-to-site connections, wg for the WireGuard
+peers and the OpenVPN server's status file for its clients.
+"""
+
+import subprocess
+import time
+
+COMMAND_TIMEOUT = 5
+
+OPENVPN_STATUS = '/run/openvpn-server/status-vpn-router.log'
+
+#: Seconds since its last handshake within which a WireGuard peer counts as connected.
+WIREGUARD_CONNECTED_SECONDS = 180
+
+
+def run(*args):
+    """The finished process of a command, or None when it cannot be run."""
+    try:
+        return subprocess.run(args, capture_output=True, text=True, timeout=COMMAND_TIMEOUT)
+    except (OSError, subprocess.TimeoutExpired):
+        return None
+
+
+def swanctl(command):
+    """The entries of a swanctl list command, or None when swanctl cannot be asked.
+
+    The --pretty output has one item per line: "name {" opens a section, "key = [" a list
+    whose items follow one per line, "}" and "]" close them, and "key = value" is a pair
+    whose value may contain spaces. Every "... event {" section at the top holds one
+    connection or SA; each becomes an entry with its name under "name". The closing
+    "... reply {" section is left out. Values stay strings, as swanctl prints them.
+    Output with more closing than opening lines gives None.
+    """
+    result = run('swanctl', command, '--pretty')
+    if result is None or result.returncode != 0:
+        return None
+    events = []
+    stack = []
+    for line in result.stdout.splitlines():
+        line = line.strip()
+        if not line:
+            continue
+        if line in ('}', ']'):
+            if not stack:
+                return None
+            stack.pop()
+        elif not stack:
+            section = {}
+            if line.endswith(' event {'):
+                events.append(section)
+            stack.append(section)
+        elif isinstance(stack[-1], list):
+            stack[-1].append(line)
+        elif line.endswith(' {'):
+            stack[-1][line[:-2]] = section = {}
+            stack.append(section)
+        elif line.endswith(' = ['):
+            stack[-1][line[:-4]] = items = []
+            stack.append(items)
+        else:
+            key, _, value = line.partition(' = ')
+            stack[-1][key] = value
+    return [dict(body, name=name) for event in events for name, body in event.items()]
+
+
+def established_each(connections):
+    """The number of established IKE SAs of each of the connections by name, None for each when swanctl cannot be asked."""
+    sas = swanctl('--list-sas')
+    return {name: None if sas is None else sum(1 for sa in sas if sa['name'] == name and sa.get('state') == 'ESTABLISHED')
+            for name in connections}
+
+
+def _count(text):
+    """A counter swanctl prints as a string, as an integer; 0 when it is not a whole number."""
+    return int(text) if isinstance(text, str) and text.isdigit() else 0
+
+
+def site_to_site_tunnels(connections):
+    """The state of each of the connections by name, or None when swanctl cannot be asked.
+
+    Each has up, 1 while it has an established IKE SA and 0 otherwise; uptime, the seconds since
+    its oldest established IKE SA was established, None while it is down; and bytes_in,
+    bytes_out, packets_in and packets_out, the sums over the child SAs of its established IKE
+    SAs. The sums start again from zero when a child SA is rekeyed.
+    """
+    sas = swanctl('--list-sas')
+    if sas is None:
+        return None
+    tunnels = {}
+    for name in connections:
+        up = [sa for sa in sas if sa['name'] == name and sa.get('state') == 'ESTABLISHED']
+        children = [child for sa in up for child in (sa.get('child-sas') or {}).values() if isinstance(child, dict)]
+        tunnels[name] = {
+            'up': 1 if up else 0,
+            'uptime': max((_count(sa.get('established')) for sa in up), default=None),
+            **{key.replace('-', '_'): sum(_count(child.get(key)) for child in children)
+               for key in ('bytes-in', 'bytes-out', 'packets-in', 'packets-out')},
+        }
+    return tunnels
+
+
+def established(connection):
+    """The number of established IKE SAs of the connection, or None when swanctl cannot be asked."""
+    return established_each([connection])[connection]
+
+
+def wireguard_peers():
+    """One entry per WireGuard peer, with its handshake age and traffic, or None when wg0 is down."""
+    result = run('wg', 'show', 'wg0', 'dump')
+    if result is None or result.returncode != 0:
+        return None
+    now = int(time.time())
+    peers = []
+    for line in result.stdout.splitlines()[1:]:
+        fields = line.split('\t')
+        if len(fields) < 7:
+            continue
+        handshake = int(fields[4])
+        peers.append({
+            'handshake_seconds_ago': now - handshake if handshake else None,
+            'received_bytes': int(fields[5]),
+            'sent_bytes': int(fields[6]),
+        })
+    return peers
+
+
+def wireguard_connected():
+    """The number of WireGuard peers with a handshake in the last WIREGUARD_CONNECTED_SECONDS, or None when wg0 is down."""
+    peers = wireguard_peers()
+    if peers is None:
+        return None
+    return sum(1 for peer in peers
+               if peer['handshake_seconds_ago'] is not None and peer['handshake_seconds_ago'] < WIREGUARD_CONNECTED_SECONDS)
+
+
+def openvpn_clients():
+    """The number of connected OpenVPN clients, from the server's status file, or None when it cannot be read."""
+    try:
+        with open(OPENVPN_STATUS, encoding='utf-8') as handle:
+            return sum(1 for line in handle if line.startswith('CLIENT_LIST,'))
+    except OSError:
+        return None
@@ -6,8 +6,12 @@ password OpenVPN checks, and a client certificate of the router CA with the user
 common name, which OpenVPN and IKEv2 accept. A Manager-only account is an account,
 simpleSecurityObject and vpnRouterAccount (the package's schema) with a name, a password and
 optionally an e-mail address, no names, no certificate and so no VPN access; it is added when
-neither the first nor the last name is given, and can sign in to the web service. Users exist
-whether or not a P2S system is enabled.
+neither the first nor the last name is given, and can sign in to the web service. A service
+account is a Manager-only account with the scope SERVICE_SCOPE in vpnRouterScope, which another
+system signs in with to use a router service, and which cannot sign in to the web service. The
+internal service accounts are those the router creates and manages for its own services
+(internal_accounts); vpn-router-setup keeps the metrics service's.
+Users exist whether or not a P2S system is enabled.

 A group is a groupOfNames in ou=groups with a name, which follows the rules of user names, an
 optional description and at least one member; a group cannot be empty, so the last member
@@ -62,7 +66,9 @@ EMAIL_MAX = 254
 #: The keys of the person attributes and their LDAP attributes.
 PERSON = (('first_name', 'givenName'), ('last_name', 'sn'), ('email', 'mail'))
 #: The attributes read for a user.
-ATTRIBUTES = ['uid', 'objectClass', 'pwdAccountLockedTime', 'givenName', 'sn', 'mail', 'oathTOTPToken']
+ATTRIBUTES = ['uid', 'objectClass', 'pwdAccountLockedTime', 'givenName', 'sn', 'mail', 'oathTOTPToken', 'vpnRouterScope']
+#: The vpnRouterScope of a service account.
+SERVICE_SCOPE = 'service'
 #: The object classes of a VPN user and of a Manager-only account.
 VPN_USER_CLASSES = [b'inetOrgPerson']
 MANAGER_ONLY_CLASSES = [b'account', b'simpleSecurityObject', b'vpnRouterAccount']
@@ -183,13 +189,33 @@ def manager_only(attributes):
    return b'account' in (value.lower() for value in attributes.get('objectClass', []))


+def service(attributes):
+    """Whether the entry is a service account."""
+    return SERVICE_SCOPE.encode() in (value.lower() for value in attributes.get('vpnRouterScope', []))
+
+
+def internal_accounts():
+    """The names of the internal service accounts, which the router creates and manages for its own services: the one
+    metrics.service_account names while metrics are enabled."""
+    try:
+        metrics = vpnrouter.load_config()['metrics']
+    except SystemExit:
+        return set()
+    return {metrics['service_account']} if metrics['enabled'] else set()
+
+
 def summary(attributes):
-    """A user as the answers show it; a person attribute the entry does not have is None."""
+    """A user as the answers show it; a person attribute the entry does not have is None.
+
+    internal is whether it is an internal service account (internal_accounts).
+    """
    name = attributes['uid'][0].decode()
    lock = attributes.get('pwdAccountLockedTime', [None])[0]
    user = {
        'name': name,
        'manager_only': manager_only(attributes),
+        'service': service(attributes),
+        'internal': service(attributes) and name in internal_accounts(),
        'enabled': lock != LOCKED,
        'locked': lock not in (None, LOCKED) and locked_since(lock) > time.time() - vpnrouter_ldap.LOCKOUT_SECONDS,
        'certificate': certificate(name)[0].is_file(),
@@ -213,12 +239,15 @@ def list_users(connection):
    return {'users': sorted((summary(attributes) for _, attributes in found), key=lambda user: user['name'])}


-def add(connection, name, password, values):
+def add(connection, name, password, values, service=False):
    """Add a user: a VPN user with its certificate when values gives all three person attributes, a Manager-only account
-    with at most the e-mail address when it gives neither name."""
+    with at most the e-mail address when it gives neither name, and, with service, a service account, with at most the
+    e-mail address too."""
    check_name(name)
    details = person(values, required=False)
    vpn_user = 'givenName' in details or 'sn' in details
+    if service and vpn_user:
+        raise Failure('a service account has no first or last name', 2)
    if vpn_user and len(details) != len(PERSON):
        raise Failure('give first_name, last_name and email for a VPN user, or at most email for a Manager-only account', 2)
    check_password(password)
@@ -229,6 +258,8 @@ def add(connection, name, password, values):
    else:
        # simpleSecurityObject requires a userPassword; passwd_s sets the real one at once.
        record = {'objectClass': MANAGER_ONLY_CLASSES, 'uid': [name.encode()], 'userPassword': [b'{CRYPT}!']}
+        if service:
+            record['vpnRouterScope'] = [SERVICE_SCOPE.encode()]
    record.update({attribute: [value.encode()] for attribute, value in details.items()})
    try:
        connection.add_s(dn_of(name), ldap.modlist.addModlist(record))
@@ -12,14 +12,27 @@ Pages:
           runs, as JSON
  /users   the users in the router's directory, whether or not a P2S system is enabled: list,
           add, change, set the password, disable, enable, remove, the OpenVPN client
-           profile, and TOTP enrolment (see users())
+           profile, and TOTP enrolment (see users()); service accounts are not among them
+  /service-accounts
+           the service accounts: list, add, change the e-mail address, set the password,
+           disable, enable, unlock and remove; the internal ones are only listed (see
+           service_accounts())
  /groups  the groups of the router's directory: list, add, rename or describe, remove, and
           add and take out members (see groups())
  /account the account of the signed-in user: its details, its password and its TOTP
           enrolment (see account())
+  /site-to-site
+           the site-to-site connections of the configuration: list, add, change and remove,
+           applied by vpn-router-setup (see site_to_site())
  /auth    sign-in with a user's password and TOTP code, refresh and sign-out (see auth())
+  /metrics/history
+           the metrics the metrics service keeps, for a view: hour, day, month or year (see
+           metrics_history())
+  /postgresql
+           the databases of each PostgreSQL cluster on the router with their sizes, as JSON (see
+           postgresql_databases()); /config has the clusters' settings

-/config, /users, /groups and /account need an HS256 JWT in an Authorization: Bearer header signed
+/config, /metrics/history, /postgresql, /users, /service-accounts, /groups, /site-to-site and /account need an HS256 JWT in an Authorization: Bearer header signed
 with vpnrouter_auth.WEB_KEY (see vpnrouter_auth.verify). A token of /auth names a user in sub;
 /account serves that user, and the other paths need a member of vpnrouter_users.ADMIN_GROUP. A
 token of vpn-router-token has the admin claim and names no user; it may call every path but
@@ -29,10 +42,13 @@ served (404) while the key does not exist. /auth is limited to AUTH_LIMIT calls
 address in AUTH_WINDOW seconds; the address of a call from one of web.trusted_proxies, by
 default the address the call came in on, is the last entry of its X-Forwarded-For header.

-/ and /status show only the status: whether the services run, the package version and the
-installed version of vpn-router-manager (manager_version, null when it is not installed), whether
-Docker is installed, and the state of site-to-site, road-warrior (IPsec P2S), OpenVPN and
-WireGuard. No configuration data, key or address is shown.
+/ and /status show only the status, as much as web.status_content says (see shown): basic, the
+default, the overall status, the time and the client's address (its address as for the rate limit
+below); standard also the package version, the installed version of vpn-router-manager
+(manager_version, null when it is not installed) and the number of active and other services; full
+whether each service runs, whether Docker is installed, and the state of each site-to-site connection, road-warrior
+(IPsec P2S), OpenVPN and WireGuard. No configuration data or key is shown, and no address but the
+client's.

 The service first initializes, without listening: it makes the signing key and the refresh
 tokens' database (vpnrouter_auth), retrying every INIT_RETRY_SECONDS until both are ready and
@@ -54,10 +70,10 @@ import collections
 import json
 import os
 import signal
-import subprocess
 import sys
 import threading
 import time
+import urllib.parse
 from html import escape
 from http.server import BaseHTTPRequestHandler

@@ -67,9 +83,11 @@ import ldap

 import vpnrouter
 import vpnrouter_auth
+import vpnrouter_metrics
 import vpnrouter_net
 import vpnrouter_serve
 import vpnrouter_users
+from vpnrouter_status import established, established_each, openvpn_clients, run, swanctl, wireguard_peers

 STATE_FILE = '/run/vpn-router/web.json'
 CONFIG_FILE = '/etc/vpn-router/vpn-router.json'
@@ -82,7 +100,6 @@ DEFAULT_PORT = 7081

 #: Seconds between two discoveries of where the service should listen.
 DISCOVERY_SECONDS = 30
-COMMAND_TIMEOUT = 5
 CACHE_SECONDS = 2

 #: The calls of /auth allowed per client address in AUTH_WINDOW seconds.
@@ -94,11 +111,16 @@ TAILWIND = 'https://cdn.jsdelivr.net/npm/@tailwindcss/browser@4'
 #: Seconds after which the status page in a browser reloads itself.
 REFRESH_SECONDS = 60

-OPENVPN_STATUS = '/run/openvpn-server/status-vpn-router.log'
+#: The PostgreSQL settings /config shows for each cluster.
+POSTGRESQL_SETTINGS = ('server_version', 'listen_addresses', 'port', 'max_connections', 'shared_buffers',
+                       'effective_cache_size', 'work_mem', 'password_encryption', 'ssl', 'timezone')

 #: The largest request body accepted, in bytes.
 BODY_LIMIT = 4096

+#: The settings of a site_to_site connection that /site-to-site adds and changes.
+CONNECTION_SETTINGS = ('addrs', 'id', 'cidrs', 'local_cidrs', 'local_id_mode', 'psk')
+
 #: The HTTP status for each status of a vpnrouter_users.Failure; any other is 500.
 USER_STATUS = {2: 400, 3: 404, 4: 409, 5: 401}

@@ -135,14 +157,6 @@ def current():
    return dict(read_json(STATE_FILE), key=vpnrouter_auth.key())


-def run(*args):
-    """The finished process of a command, or None when it cannot be run."""
-    try:
-        return subprocess.run(args, capture_output=True, text=True, timeout=COMMAND_TIMEOUT)
-    except (OSError, subprocess.TimeoutExpired):
-        return None
-
-
 def unit_state(unit):
    result = run('systemctl', 'is-active', unit)
    return result.stdout.strip() if result and result.stdout.strip() else 'unknown'
@@ -166,85 +180,6 @@ def docker_status():
    }


-def swanctl(command):
-    """The entries of a swanctl list command, or None when swanctl cannot be asked.
-
-    The --pretty output has one item per line: "name {" opens a section, "key = [" a list
-    whose items follow one per line, "}" and "]" close them, and "key = value" is a pair
-    whose value may contain spaces. Every "... event {" section at the top holds one
-    connection or SA; each becomes an entry with its name under "name". The closing
-    "... reply {" section is left out. Values stay strings, as swanctl prints them.
-    Output with more closing than opening lines gives None.
-    """
-    result = run('swanctl', command, '--pretty')
-    if result is None or result.returncode != 0:
-        return None
-    events = []
-    stack = []
-    for line in result.stdout.splitlines():
-        line = line.strip()
-        if not line:
-            continue
-        if line in ('}', ']'):
-            if not stack:
-                return None
-            stack.pop()
-        elif not stack:
-            section = {}
-            if line.endswith(' event {'):
-                events.append(section)
-            stack.append(section)
-        elif isinstance(stack[-1], list):
-            stack[-1].append(line)
-        elif line.endswith(' {'):
-            stack[-1][line[:-2]] = section = {}
-            stack.append(section)
-        elif line.endswith(' = ['):
-            stack[-1][line[:-4]] = items = []
-            stack.append(items)
-        else:
-            key, _, value = line.partition(' = ')
-            stack[-1][key] = value
-    return [dict(body, name=name) for event in events for name, body in event.items()]
-
-
-def established(connection):
-    """The number of established IKE SAs of the connection, or None when swanctl cannot be asked."""
-    sas = swanctl('--list-sas')
-    if sas is None:
-        return None
-    return sum(1 for sa in sas if sa['name'] == connection and sa.get('state') == 'ESTABLISHED')
-
-
-def wireguard_peers():
-    """One entry per WireGuard peer, with its handshake age and traffic, or None when wg0 is down."""
-    result = run('wg', 'show', 'wg0', 'dump')
-    if result is None or result.returncode != 0:
-        return None
-    now = int(time.time())
-    peers = []
-    for line in result.stdout.splitlines()[1:]:
-        fields = line.split('\t')
-        if len(fields) < 7:
-            continue
-        handshake = int(fields[4])
-        peers.append({
-            'handshake_seconds_ago': now - handshake if handshake else None,
-            'received_bytes': int(fields[5]),
-            'sent_bytes': int(fields[6]),
-        })
-    return peers
-
-
-def openvpn_clients():
-    """The number of connected OpenVPN clients, from the server's status file, or None when it cannot be read."""
-    try:
-        with open(OPENVPN_STATUS, encoding='utf-8') as handle:
-            return sum(1 for line in handle if line.startswith('CLIENT_LIST,'))
-    except OSError:
-        return None
-
-
 def postgresql_clusters():
    """The state of each PostgreSQL cluster unit (postgresql@<version>-<name>), or {'postgresql': 'no cluster'} without one.

@@ -277,9 +212,10 @@ def collect(state):
        'units': units,
        'docker': docker_status(),
    }
-    if state.get('site_to_site'):
-        count = established('remote-site')
-        status['site_to_site'] = {'established': None if count is None else count > 0}
+    names = state.get('site_to_site')
+    if isinstance(names, list) and names:
+        status['site_to_site'] = {'connections': {name: None if count is None else count > 0
+                                                  for name, count in established_each(names).items()}}
    if state.get('p2s'):
        status['p2s'] = {'clients': established('road-warrior')}
    if state.get('wireguard'):
@@ -289,6 +225,26 @@ def collect(state):
    return status


+def shown(status, content, client):
+    """The status document as web.status_content shows it to the client at its address.
+
+    Every content has status, time and client_ip, the client's address, and content, which one it is: basic nothing
+    more; standard adds version, manager_version and services, the number of active units and of units in every
+    other state; full adds the whole status document of collect. Content that is not one of
+    vpnrouter.STATUS_CONTENTS, or not set, is basic.
+    """
+    if content not in vpnrouter.STATUS_CONTENTS:
+        content = 'basic'
+    if content == 'full':
+        return {**status, 'content': content, 'client_ip': client}
+    document = {'status': status['status'], 'content': content, 'time': status['time'], 'client_ip': client}
+    if content == 'standard':
+        active = sum(1 for value in status['units'].values() if value == 'active')
+        document.update(version=status['version'], manager_version=status['manager_version'],
+                        services={'active': active, 'failed': len(status['units']) - active})
+    return document
+
+
 def lines_of(*args):
    """The output lines of a command, or None when it fails."""
    result = run(*args)
@@ -327,6 +283,65 @@ def wireguard_details():
    }


+def postgresql_query(cluster, sql):
+    """The JSON value an SQL statement answers on a cluster (version/name), run by psql as postgres, or None when it fails."""
+    result = run('runuser', '-u', 'postgres', '--', 'psql', '--cluster', cluster, '-X', '-q', '-t', '-A',
+                 '-v', 'ON_ERROR_STOP=1', '-d', 'postgres', '-c', sql)
+    if result is None or result.returncode != 0:
+        return None
+    try:
+        return json.loads(result.stdout)
+    except ValueError:
+        return None
+
+
+def postgresql_clusters_of():
+    """The PostgreSQL clusters of pg_lsclusters, each with version, name, port, status and data_directory, or None when it fails."""
+    lines = lines_of('pg_lsclusters', '--no-header')
+    if lines is None:
+        return None
+    clusters = []
+    for line in lines:
+        fields = line.split()
+        if len(fields) >= 6:
+            clusters.append({'version': fields[0], 'name': fields[1], 'port': int(fields[2]) if fields[2].isdigit() else None,
+                             'status': fields[3], 'data_directory': fields[5]})
+    return clusters
+
+
+def postgresql_configuration():
+    """The PostgreSQL clusters on the router with the settings of POSTGRESQL_SETTINGS of each one that is online (None
+    for one that is not), or None when pg_lsclusters fails."""
+    clusters = postgresql_clusters_of()
+    if clusters is None:
+        return None
+    names = ', '.join(f"'{name}'" for name in POSTGRESQL_SETTINGS)
+    for cluster in clusters:
+        cluster['settings'] = postgresql_query(
+            f"{cluster['version']}/{cluster['name']}",
+            f'SELECT json_object_agg(name, current_setting(name) ORDER BY name) FROM pg_settings WHERE name IN ({names})',
+        ) if cluster['status'].startswith('online') else None
+    return {'clusters': clusters}
+
+
+def postgresql_databases():
+    """What /postgresql shows: the PostgreSQL clusters on the router, each with its databases (name, owner, encoding and
+    size in bytes) and their total size, None for a cluster that is not online; clusters is None when pg_lsclusters fails."""
+    clusters = postgresql_clusters_of()
+    if clusters is None:
+        return {'clusters': None}
+    for cluster in clusters:
+        databases = postgresql_query(
+            f"{cluster['version']}/{cluster['name']}",
+            "SELECT coalesce(json_agg(json_build_object('name', datname, 'owner', pg_get_userbyid(datdba), "
+            "'encoding', pg_encoding_to_char(encoding), 'size', pg_database_size(oid)) ORDER BY datname), '[]') "
+            'FROM pg_database',
+        ) if cluster['status'].startswith('online') else None
+        cluster['databases'] = databases
+        cluster['size'] = sum(database['size'] for database in databases) if isinstance(databases, list) else None
+    return {'clusters': clusters}
+
+
 def details(state):
    """What /config shows: the configuration without its secrets, and what the router resolved and runs."""
    configuration = state.get('configuration', {})
@@ -342,20 +357,27 @@ def details(state):
            'exposed_ports': configuration.get('docker', {}).get('exposed_ports', []),
            'rules': lines_of('iptables', '-S', 'VPN-ROUTER-DOCKER'),
        },
+        'postgresql': postgresql_configuration(),
    }


 def text_of(status):
-    """The status for people, as plain text."""
-    lines = ['VPN Router', f'Status: {status["status"]}', f'Version: {status["version"] or "unknown"}', '']
-    lines.append(f'Router Manager: {status["manager_version"] or "not installed"}')
-    lines += [f'{name}: {value}' for name, value in status['units'].items()]
-    docker = status['docker']
-    lines.append('Docker: not installed' if not docker['installed']
-                 else f'Docker: installed, service {docker["service"]}, rules {docker["rules"]}')
-    if 'site_to_site' in status:
-        value = status['site_to_site']['established']
-        lines.append(f'Site to site: {"unknown" if value is None else "established" if value else "not established"}')
+    """The status document of shown for people, as plain text: a header, a blank line, then name: value lines."""
+    lines = ['VPN Router', f'Status: {status["status"]}']
+    if 'version' in status:
+        lines.append(f'Version: {status["version"] or "unknown"}')
+    lines += ['', f'Client IP: {status["client_ip"]}']
+    if 'manager_version' in status:
+        lines.append(f'Router Manager: {status["manager_version"] or "not installed"}')
+    if 'services' in status:
+        lines.append(f'Services: {status["services"]["active"]} active, {status["services"]["failed"]} failed')
+    lines += [f'{name}: {value}' for name, value in status.get('units', {}).items()]
+    if 'docker' in status:
+        docker = status['docker']
+        lines.append('Docker: not installed' if not docker['installed']
+                     else f'Docker: installed, service {docker["service"]}, rules {docker["rules"]}')
+    for name, value in status.get('site_to_site', {}).get('connections', {}).items():
+        lines.append(f'Site to site {name}: {"unknown" if value is None else "established" if value else "not established"}')
    if 'p2s' in status:
        clients = status['p2s']['clients']
        lines.append(f'Road-warrior (IPsec P2S): {"unknown" if clients is None else f"{clients} connected"}')
@@ -376,11 +398,12 @@ def text_of(status):


 def html_of(status):
-    """The status for a browser, as a page styled with Tailwind CSS."""
+    """The status document of shown for a browser, as a page styled with Tailwind CSS."""
    colour = 'bg-emerald-600 dark:bg-emerald-700' if status['status'] == 'ok' else 'bg-amber-600 dark:bg-amber-700'
-    # Each "name: value" line of the text is a row; indented lines, such as WireGuard peers, are indented here too.
+    version = f', version {status["version"] or "unknown"}' if 'version' in status else ''
+    # Each "name: value" line after the header of the text is a row; indented lines, such as WireGuard peers, are indented here too.
    rows = []
-    for line in text_of(status).splitlines()[4:]:
+    for line in text_of(status).split('\n\n', 1)[1].splitlines():
        if not line:
            continue
        name, _, value = line.partition(': ')
@@ -404,7 +427,7 @@ def html_of(status):
      <div class="overflow-hidden rounded-2xl border border-slate-200 bg-white shadow-lg dark:border-slate-700 dark:bg-slate-800">
        <div class="{colour} px-6 py-4 text-white">
          <h1 class="text-xl font-semibold">VPN Router</h1>
-          <p class="mt-1 text-sm">Status: {escape(status['status'])}, version {escape(status['version'] or 'unknown')}</p>
+          <p class="mt-1 text-sm">Status: {escape(status['status'] + version)}</p>
        </div>
        <div class="px-6 py-4">
          <table class="w-full text-sm"><tbody>{body}</tbody></table>
@@ -422,7 +445,7 @@ def users(state, method, path, body):

      GET    /users                   the users
      POST   /users                   add a user: {"name", "password", "first_name", "last_name", "email"};
-                                      without the last three a Manager-only account
+                                      without the names a Manager-only account
      PUT    /users/<name>            change any of {"first_name", "last_name", "email"}
      PUT    /users/<name>/password   set the password: {"password": ...}
      POST   /users/<name>/disable    lock the user out of OpenVPN
@@ -433,6 +456,8 @@ def users(state, method, path, body):
      POST   /users/<name>/otp        a new TOTP secret and its otpauth URI; nothing is stored
      PUT    /users/<name>/otp        store a TOTP secret: {"secret", "code"}, code a code of the secret
      DELETE /users/<name>/otp        remove the TOTP token
+
+    Service accounts are served by /service-accounts: they are not listed, and a request naming one is 404.
    """
    if body == 'invalid' or (body is not None and not isinstance(body, dict)):
        return 400, {'error': 'the body must be a JSON object'}
@@ -441,7 +466,8 @@ def users(state, method, path, body):
    route = (method, len(parts), parts[2] if len(parts) == 3 else None)
    name = parts[1] if len(parts) > 1 else None
    actions = {
-        ('GET', 1, None): lambda connection: vpnrouter_users.list_users(connection),
+        ('GET', 1, None): lambda connection: {
+            'users': [user for user in vpnrouter_users.list_users(connection)['users'] if not user['service']]},
        ('POST', 1, None): lambda connection: vpnrouter_users.add(connection, body.get('name'), body.get('password'), body),
        ('PUT', 2, None): lambda connection: vpnrouter_users.update(connection, name, body),
        ('PUT', 3, 'password'): lambda connection: vpnrouter_users.passwd(connection, name, body.get('password')),
@@ -461,6 +487,8 @@ def users(state, method, path, body):
        return 404, {'error': f'no route {method} {path}'}
    try:
        with vpnrouter_users.session() as connection:
+            if name is not None and vpnrouter_users.service(vpnrouter_users.entry(connection, name)):
+                raise vpnrouter_users.Failure(f'{name} is a service account; see /service-accounts', 3)
            document = actions[route](connection)
        if operations.get(route) in vpnrouter_auth.REVOKING:
            vpnrouter_auth.revoke(vpnrouter.load_config(), name)
@@ -476,6 +504,56 @@ def users(state, method, path, body):
    return (201 if route == ('POST', 1, None) else 200), document


+def service_accounts(method, path, body):
+    """Answer a /service-accounts request with vpnrouter_users: the HTTP status and the JSON document.
+
+      GET    /service-accounts                   the service accounts: {"service_accounts": [...]}
+      POST   /service-accounts                   add one: {"name", "password", "email"?}
+      PUT    /service-accounts/<name>            change the e-mail address: {"email"}; "" removes it
+      PUT    /service-accounts/<name>/password   set the password: {"password": ...}
+      POST   /service-accounts/<name>/disable    lock it out
+      POST   /service-accounts/<name>/enable     let it in again
+      POST   /service-accounts/<name>/unlock     end a lockout after failed logins
+      DELETE /service-accounts/<name>            remove it
+
+    A name that is not a service account is 404. The internal service accounts (vpnrouter_users.internal_accounts),
+    which the router manages, are only listed: every other request on one is refused with 403.
+    """
+    if body == 'invalid' or (body is not None and not isinstance(body, dict)):
+        return 400, {'error': 'the body must be a JSON object'}
+    body = body or {}
+    parts = path.strip('/').split('/')
+    route = (method, len(parts), parts[2] if len(parts) == 3 else None)
+    name = parts[1] if len(parts) > 1 else None
+    email = {'email': body.get('email')}
+    actions = {
+        ('GET', 1, None): lambda connection: {
+            'service_accounts': [user for user in vpnrouter_users.list_users(connection)['users'] if user['service']]},
+        ('POST', 1, None): lambda connection: vpnrouter_users.add(connection, body.get('name'), body.get('password'), email,
+                                                                  service=True),
+        ('PUT', 2, None): lambda connection: vpnrouter_users.update(connection, name, email),
+        ('PUT', 3, 'password'): lambda connection: vpnrouter_users.passwd(connection, name, body.get('password')),
+        ('POST', 3, 'disable'): lambda connection: vpnrouter_users.disable(connection, name),
+        ('POST', 3, 'enable'): lambda connection: vpnrouter_users.enable(connection, name),
+        ('POST', 3, 'unlock'): lambda connection: vpnrouter_users.unlock(connection, name),
+        ('DELETE', 2, None): lambda connection: vpnrouter_users.remove(connection, name),
+    }
+    if route not in actions:
+        return 404, {'error': f'no route {method} {path}'}
+    if name is not None and name in vpnrouter_users.internal_accounts():
+        return 403, {'error': f'{name} is an internal service account, which the router manages'}
+    try:
+        with vpnrouter_users.session() as connection:
+            if name is not None and not vpnrouter_users.service(vpnrouter_users.entry(connection, name)):
+                raise vpnrouter_users.Failure(f'{name} is not a service account', 3)
+            document = actions[route](connection)
+    except vpnrouter_users.Failure as failure:
+        return USER_STATUS.get(failure.status, 500), {'error': str(failure)}
+    except (ldap.LDAPError, OSError) as exc:
+        return 500, {'error': f'the user directory failed: {exc}'}
+    return (201 if route == ('POST', 1, None) else 200), document
+
+
 def groups(state, method, path, body):
    """Answer a /groups request with vpnrouter_users: the HTTP status and the JSON document.

@@ -485,6 +563,9 @@ def groups(state, method, path, body):
      DELETE /groups/<name>                   remove the group; its members are kept
      POST   /groups/<name>/members           add a member: {"user": ...}
      DELETE /groups/<name>/members/<user>    take a member out; the last member cannot leave
+
+    An internal service account (vpnrouter_users.internal_accounts) is not put in or taken out of a group: such a
+    request is refused with 403.
    """
    if body == 'invalid' or (body is not None and not isinstance(body, dict)):
        return 400, {'error': 'the body must be a JSON object'}
@@ -492,6 +573,12 @@ def groups(state, method, path, body):
    parts = path.strip('/').split('/')
    name = parts[1] if len(parts) > 1 else None
    route = (method, len(parts), parts[2] if len(parts) > 2 else None)
+    members = body.get('members') if route == ('POST', 1, None) else [body.get('user')] if route == ('POST', 3, 'members') \
+        else [parts[3]] if route == ('DELETE', 4, 'members') else []
+    internal = sorted(vpnrouter_users.internal_accounts().intersection(
+        member for member in (members if isinstance(members, list) else []) if isinstance(member, str)))
+    if internal:
+        return 403, {'error': f'{", ".join(internal)}: internal service accounts, which the router manages, are not group members'}
    actions = {
        ('GET', 1, None): lambda connection: vpnrouter_users.list_groups(connection),
        ('POST', 1, None): lambda connection: vpnrouter_users.group_add(
@@ -514,6 +601,81 @@ def groups(state, method, path, body):
    return (201 if route == ('POST', 1, None) else 200), document


+def connection_of(name, connection, count):
+    """A site_to_site connection as /site-to-site shows it: its settings but psk, psk_set and established.
+
+    count is the number of its established IKE SAs, None when it is not known.
+    """
+    return {'name': name, **{option: value for option, value in connection.items() if option != 'psk'},
+            'psk_set': bool(connection['psk']), 'established': None if count is None else count > 0}
+
+
+def site_to_site(method, path, body):
+    """Answer a /site-to-site request: the HTTP status and the JSON document.
+
+      GET    /site-to-site          the connections, {"connections": [...]}: each with its settings but psk, with
+                                    psk_set, whether psk holds a key, and established, whether its tunnel is up,
+                                    null when swanctl cannot be asked
+      POST   /site-to-site          add a connection: {"name", "addrs", "id", "cidrs", "local_cidrs", "local_id_mode",
+                                    "psk"}; psk is required, and an existing name is 409
+      PUT    /site-to-site/<name>   change any of the settings of POST but name; an empty or absent psk keeps the
+                                    current key, and a psk given replaces psk_file
+      DELETE /site-to-site/<name>   remove the connection
+
+    A change is made holding vpnrouter.config_lock, checked as vpn-router-setup checks the configuration (400 with
+    the reason), written with vpnrouter.save_config, and applied by restarting vpn-router-setup without waiting for it.
+    """
+    if body == 'invalid' or (body is not None and not isinstance(body, dict)):
+        return 400, {'error': 'the body must be a JSON object'}
+    body = body or {}
+    parts = path.strip('/').split('/')
+    name = parts[1] if len(parts) == 2 else None
+    if (method, len(parts)) not in (('GET', 1), ('POST', 1), ('PUT', 2), ('DELETE', 2)):
+        return 404, {'error': f'no route {method} {path}'}
+    try:
+        if method == 'GET':
+            connections = vpnrouter.load_config()['site_to_site']
+            counts = established_each(connections)
+            return 200, {'connections': [connection_of(key, value, counts[key]) for key, value in connections.items()]}
+        settings = {option: body[option] for option in CONNECTION_SETTINGS if option in body}
+        with vpnrouter.config_lock():
+            data = vpnrouter.read_settings()
+            connections = data.setdefault('site_to_site', {})
+            if method == 'POST':
+                name = body.get('name')
+                if not isinstance(name, str) or not name:
+                    return 400, {'error': 'name is required'}
+                if name in connections:
+                    return 409, {'error': f'connection {name} exists'}
+                if not isinstance(settings.get('psk'), str) or not settings['psk']:
+                    return 400, {'error': 'psk is required'}
+                connections[name] = settings
+            elif name not in connections:
+                return 404, {'error': f'no connection {name}'}
+            elif method == 'PUT':
+                connection = dict(connections[name]) if isinstance(connections[name], dict) else {}
+                if settings.get('psk'):
+                    connection.pop('psk_file', None)
+                else:
+                    settings.pop('psk', None)
+                connections[name] = {**connection, **settings}
+            else:
+                del connections[name]
+            cfg = vpnrouter.with_defaults(data)
+            vpnrouter.validate(cfg)
+            vpnrouter.save_config(data)
+    except vpnrouter.ConfigError as exc:
+        return 400, {'error': str(exc)}
+    except OSError as exc:
+        return 500, {'error': f'the configuration cannot be written: {exc}'}
+    except SystemExit as exc:
+        return 500, {'error': str(exc.code)}
+    run('systemctl', 'restart', '--no-block', 'vpn-router-setup.service')
+    if method == 'DELETE':
+        return 200, {'name': name, 'removed': True}
+    return (201 if method == 'POST' else 200), connection_of(name, cfg['site_to_site'][name], None)
+
+
 def account(name, method, path, body):
    """Answer an /account request of the user named by the token with vpnrouter_users: the HTTP status and the JSON document.

@@ -562,8 +724,25 @@ def account(name, method, path, body):
    return 200, document


+def metrics_history(view):
+    """Answer GET /metrics/history?range=<view> with vpnrouter_metrics.history: the HTTP status and the JSON document.
+
+    view is hour, the default, day, month or year (vpnrouter_metrics.RANGES).
+    """
+    if view not in vpnrouter_metrics.RANGES:
+        return 400, {'error': f'range must be one of {", ".join(vpnrouter_metrics.RANGES)}'}
+    try:
+        with vpnrouter_metrics.database(vpnrouter.load_config()) as connection:
+            return 200, vpnrouter_metrics.history(connection, view)
+    except vpnrouter_metrics.DatabaseError as exc:
+        return 500, {'error': str(exc)}
+    except SystemExit as exc:
+        return 500, {'error': str(exc.code)}
+
+
 def changes_admins(connection, method, parts, body):
-    """Whether a /users or /groups request creates, renames to, changes or removes ADMIN_GROUP, or removes a member of it."""
+    """Whether a /users, /service-accounts or /groups request creates, renames to, changes or removes ADMIN_GROUP, or
+    removes a member of it."""
    admins = vpnrouter_users.ADMIN_GROUP
    if parts[0] == 'groups':
        if method == 'POST' and len(parts) == 1:
@@ -571,7 +750,7 @@ def changes_admins(connection, method, parts, body):
        if method != 'GET' and len(parts) > 1 and parts[1] == admins:
            return True
        return method == 'PUT' and len(parts) == 2 and body.get('name') == admins
-    if parts[0] == 'users' and method == 'DELETE' and len(parts) == 2:
+    if parts[0] in ('users', 'service-accounts') and method == 'DELETE' and len(parts) == 2:
        return admins in vpnrouter_users.groups_of(connection, parts[1])
    return False

@@ -607,6 +786,9 @@ def auth(path, body):
        cfg = vpnrouter.load_config()
        if path == '/auth':
            vpnrouter_users.login(body.get('name'), body.get('password'), body.get('code'))
+            with vpnrouter_users.session() as connection:
+                if vpnrouter_users.service(vpnrouter_users.entry(connection, body['name'])):
+                    raise vpnrouter_users.Failure('the name, the password or the code is wrong', 5)
            return 200, vpnrouter_auth.issue(cfg, body['name'])
        name = vpnrouter_auth.take(cfg, body.get('refresh_token'))
        if path == '/auth/logout':
@@ -682,8 +864,9 @@ class Handler(BaseHTTPRequestHandler):
        # A body that is not read must not be taken for the next request.
        if self.command not in ('GET', 'HEAD'):
            self.close_connection = True
-        directory = next((name for name in ('users', 'groups', 'account') if path == f'/{name}' or path.startswith(f'/{name}/')), None)
-        protected = path == '/config' or directory is not None
+        directory = next((name for name in ('users', 'service-accounts', 'groups', 'account', 'site-to-site')
+                          if path == f'/{name}' or path.startswith(f'/{name}/')), None)
+        protected = path in ('/config', '/metrics/history', '/postgresql') or directory is not None
        signing = path in ('/auth', '/auth/refresh', '/auth/logout')
        state = current() if protected or signing else {}
        claims = self.claims(state['key']) if protected and state['key'] else None
@@ -710,22 +893,35 @@ class Handler(BaseHTTPRequestHandler):
            body = json.dumps({'error': refused[1]}, indent=2).encode() + b'\n'
        elif path == '/config' and self.command in ('GET', 'HEAD'):
            body, kind, code = json.dumps(details(state), indent=2).encode() + b'\n', 'application/json', 200
+        elif path == '/postgresql' and self.command in ('GET', 'HEAD'):
+            body, kind, code = json.dumps(postgresql_databases(), indent=2).encode() + b'\n', 'application/json', 200
+        elif path == '/metrics/history' and self.command in ('GET', 'HEAD'):
+            query = urllib.parse.parse_qs(urllib.parse.urlsplit(self.path).query)
+            code, document = metrics_history(query.get('range', ['hour'])[0])
+            body, kind = json.dumps(document).encode() + b'\n', 'application/json'
        elif directory == 'account':
            code, document = account(claims['sub'], self.command, path, payload)
            body, kind = json.dumps(document, indent=2).encode() + b'\n', 'application/json'
-        elif protected and path != '/config':
+        elif directory == 'site-to-site':
+            code, document = site_to_site(self.command, path, payload)
+            body, kind = json.dumps(document, indent=2).encode() + b'\n', 'application/json'
+        elif directory == 'service-accounts':
+            code, document = service_accounts(self.command, path, payload)
+            body, kind = json.dumps(document, indent=2).encode() + b'\n', 'application/json'
+        elif directory is not None:
            code, document = (users if directory == 'users' else groups)(state, self.command, path, payload)
            body, kind = json.dumps(document, indent=2).encode() + b'\n', 'application/json'
        elif self.command not in ('GET', 'HEAD'):
            body, kind, code = b'Method not allowed\n', 'text/plain; charset=utf-8', 405
-        elif path == '/status':
-            body, kind, code = json.dumps(self.status(), indent=2).encode() + b'\n', 'application/json', 200
-        elif path == '/':
+        elif path in ('/status', '/'):
+            document = shown(self.status(), section(read_json(CONFIG_FILE), 'web').get('status_content'), self.client())
            agent = self.headers.get('User-Agent', '').lower()
-            if 'curl' in agent or 'wget' in agent:
-                body, kind = text_of(self.status()).encode(), 'text/plain; charset=utf-8'
+            if path == '/status':
+                body, kind = json.dumps(document, indent=2).encode() + b'\n', 'application/json'
+            elif 'curl' in agent or 'wget' in agent:
+                body, kind = text_of(document).encode(), 'text/plain; charset=utf-8'
            else:
-                body, kind = html_of(self.status()).encode(), 'text/html; charset=utf-8'
+                body, kind = html_of(document).encode(), 'text/html; charset=utf-8'
            code = 200
        else:
            body, kind, code = b'Not found\n', 'text/plain; charset=utf-8', 404
@@ -0,0 +1,132 @@
+#!/usr/bin/python3
+"""Show and change the router's configuration, /etc/vpn-router/vpn-router.json.
+
+show prints the file as indented JSON; the file is not changed. set takes a setting as
+section.option, such as web.port, or as site_to_site.NAME.option for a site-to-site connection,
+which it creates with the defaults (vpnrouter.CONNECTION) when it does not exist, and a value,
+which it converts to the type the package's schema (vpnrouter.SCHEMA) gives the setting: a whole
+number, true or false, a list of strings separated by commas (an empty value is an empty list),
+or a string. remove takes site_to_site.NAME and removes that connection. The configuration with
+the change is checked as vpn-router-setup checks it, and only then written with
+vpnrouter.save_config, holding vpnrouter.config_lock; vpn-router-setup applies it at its next
+run, which set and remove remind of. A failure is a message on standard error; the exit status
+is 2 for an invalid request and 1 for any other failure. -h or --help shows the options.
+
+  vpn-config-edit show
+  vpn-config-edit set SECTION.OPTION VALUE
+  vpn-config-edit set site_to_site.NAME.OPTION VALUE
+  vpn-config-edit remove site_to_site.NAME
+"""
+
+import argparse
+import copy
+import json
+import sys
+
+sys.path.insert(0, '/usr/lib/vpn-router')
+
+import vpnrouter
+
+
+class Failure(Exception):
+    """A request that cannot be done; status is 2 invalid, 1 other."""
+
+    def __init__(self, message, status=1):
+        super().__init__(message)
+        self.status = status
+
+
+class Parser(argparse.ArgumentParser):
+    """An argument parser whose errors are Failures with status 2."""
+
+    def error(self, message):
+        raise Failure(f'{message}; see {self.prog} --help', 2)
+
+
+def read():
+    """The settings in the configuration file, without the defaults; {} when the file does not exist."""
+    try:
+        return vpnrouter.read_settings()
+    except vpnrouter.ConfigError as exc:
+        raise Failure(str(exc))
+
+
+def converted(key, text):
+    """The path of the setting key, section.option or site_to_site.NAME.option, and text as the type the schema gives it."""
+    path = key.split('.')
+    if path[0] == 'site_to_site' and len(path) == 3 and path[2] in vpnrouter.CONNECTION:
+        kind = type(vpnrouter.CONNECTION[path[2]])
+    elif path[0] != 'site_to_site' and len(path) == 2 and path[0] in vpnrouter.SCHEMA and path[1] in vpnrouter.SCHEMA[path[0]]:
+        kind = type(vpnrouter.SCHEMA[path[0]][path[1]])
+    else:
+        raise Failure(f'{key}: unknown setting; settings are section.option, such as web.port, '
+                      'or site_to_site.NAME.option', 2)
+    if kind is bool:
+        if text not in ('true', 'false'):
+            raise Failure(f'{key} takes true or false', 2)
+        return path, text == 'true'
+    if kind is int:
+        try:
+            return path, int(text)
+        except ValueError:
+            raise Failure(f'{key} takes a whole number', 2)
+    if kind is list:
+        return path, [item.strip() for item in text.split(',') if item.strip()]
+    return path, text
+
+
+def main(argv):
+    try:
+        parser = Parser(prog='vpn-config-edit', description='Show and change the router configuration.')
+        commands = parser.add_subparsers(dest='command', required=True, parser_class=Parser)
+        commands.add_parser('show', help='print the configuration as indented JSON')
+        setter = commands.add_parser('set', help='set a setting and write the configuration')
+        setter.add_argument('key', metavar='SECTION.OPTION',
+                            help='the setting, such as web.port or site_to_site.NAME.option')
+        setter.add_argument('value', metavar='VALUE', help='its value; a list separated by commas')
+        remover = commands.add_parser('remove', help='remove a site-to-site connection and write the configuration')
+        remover.add_argument('key', metavar='site_to_site.NAME', help='the connection')
+        options = parser.parse_args(argv)
+
+        if options.command == 'show':
+            print(json.dumps(read(), indent=2))
+            return 0
+
+        with vpnrouter.config_lock():
+            data = read()
+            if options.command == 'set':
+                path, value = converted(options.key, options.value)
+                if path[0] == 'site_to_site':
+                    connections = data.setdefault('site_to_site', {})
+                    connection = connections.setdefault(path[1], copy.deepcopy(vpnrouter.CONNECTION))
+                    if not isinstance(connection, dict):
+                        raise Failure(f'site_to_site.{path[1]} is not an object')
+                    connection[path[2]] = value
+                else:
+                    data.setdefault(path[0], {})[path[1]] = value
+            else:
+                section, _, name = options.key.partition('.')
+                if section != 'site_to_site' or not name or name not in data.get('site_to_site', {}):
+                    raise Failure(f'{options.key}: no such site-to-site connection', 2)
+                del data['site_to_site'][name]
+            try:
+                vpnrouter.validate(vpnrouter.with_defaults(data))
+            except vpnrouter.ConfigError as exc:
+                raise Failure(str(exc), 2)
+            vpnrouter.save_config(data)
+    except Failure as failure:
+        print(f'vpn-config-edit: {failure}', file=sys.stderr)
+        return failure.status
+    except OSError as exc:
+        print(f'vpn-config-edit: {exc}', file=sys.stderr)
+        return 1
+    if options.command == 'set':
+        print(f'{options.key} set to {json.dumps(value)} in {vpnrouter.CONFIG_FILE}.')
+    else:
+        print(f'{options.key} removed from {vpnrouter.CONFIG_FILE}.')
+    print('Apply it with: systemctl restart vpn-router-setup')
+    return 0
+
+
+if __name__ == '__main__':
+    sys.exit(main(sys.argv[1:]))
@@ -11,6 +11,7 @@ user exists, 1 anything else. -h or --help shows the commands and their options.
  vpn-router-user [--json] list
  vpn-router-user [--json] add <name> --first-name F --last-name L --email E   (password on stdin)
  vpn-router-user [--json] add <name> [--email E]   (a Manager-only account; password on stdin)
+  vpn-router-user [--json] add <name> --service [--email E]   (a service account; password on stdin)
  vpn-router-user [--json] update <name> [--first-name F] [--last-name L] [--email E]
  vpn-router-user [--json] passwd <name>       (password on stdin)
  vpn-router-user [--json] disable <name>
@@ -40,7 +41,8 @@ from vpnrouter_users import Failure
 HELP = {
    'list': 'list the users',
    'add': 'add a VPN user with the three person options and issue the certificate, or without the names a '
-           'Manager-only account, with an optional e-mail address; the password is read from standard input',
+           'Manager-only account, or with --service a service account, each with an optional e-mail address; the '
+           'password is read from standard input',
    'update': "change the first name, the last name or the e-mail address; a Manager-only account has only the "
              "e-mail address, which '' removes",
    'passwd': 'set the password, read from standard input',
@@ -76,6 +78,8 @@ def parse(argv):
        if command in ('add', 'update'):
            for key, _ in vpnrouter_users.PERSON:
                sub.add_argument(f'--{key.replace("_", "-")}', dest=key, metavar='TEXT', help=PERSON_HELP[key])
+        if command == 'add':
+            sub.add_argument('--service', action='store_true', help='add a service account, which cannot sign in to the web service')
        if command == 'otp-enrol':
            sub.add_argument('code', help='a code of the secret from the authenticator')
    return parser.parse_args(argv)
@@ -93,7 +97,7 @@ def run(connection, options, secret):
        return vpnrouter_users.list_users(connection)
    values = {key: getattr(options, key, None) for key, _ in vpnrouter_users.PERSON}
    if command == 'add':
-        return vpnrouter_users.add(connection, options.name, secret, values)
+        return vpnrouter_users.add(connection, options.name, secret, values, service=options.service)
    if command == 'update':
        return vpnrouter_users.update(connection, options.name, values)
    if command == 'passwd':
@@ -115,7 +119,7 @@ def text_of(answer):
    if not users:
        return 'no users'
    head = ('USER', 'KIND', 'STATE', 'CERTIFICATE', 'OTP', 'FIRST NAME', 'LAST NAME', 'E-MAIL')
-    rows = [(user['name'], 'manager' if user['manager_only'] else 'vpn',
+    rows = [(user['name'], 'internal' if user['internal'] else 'service' if user['service'] else 'manager' if user['manager_only'] else 'vpn',
             'disabled' if not user['enabled'] else 'locked' if user['locked'] else 'enabled',
             'issued' if user['certificate'] else 'missing',
             'enrolled' if user['otp'] else '-', user['first_name'] or '-', user['last_name'] or '-', user['email'] or '-')
@@ -8,20 +8,23 @@
    "internal": "eth1"
  },
  "wan": {
-    "local_fqdn": "router.example.com",
-    "local_id_mode": "fqdn"
+    "local_fqdn": "router.example.com"
  },
  "local": {
    "cidrs": ["10.0.0.0/24"],
    "int_addr": "10.1.1.4",
    "int_gateway_ip": "10.1.1.1"
  },
-  "remote": {
-    "addrs": ["peer.example.net"],
-    "id": "peer.example.net",
-    "cidrs": ["192.168.0.0/24"],
-    "psk": "change-me",
-    "psk_file": ""
+  "site_to_site": {
+    "remote-site": {
+      "addrs": ["peer.example.net"],
+      "id": "peer.example.net",
+      "cidrs": ["192.168.0.0/24"],
+      "local_cidrs": ["10.0.0.0/24"],
+      "local_id_mode": "fqdn",
+      "psk": "change-me",
+      "psk_file": ""
+    }
  },
  "p2s": {
    "enabled": false,
@@ -48,6 +51,28 @@
    "listen": "both",
    "port": 7081,
    "database": "",
-    "trusted_proxies": []
+    "trusted_proxies": [],
+    "status_content": "basic"
+  },
+  "https": {
+    "enabled": true,
+    "email": "",
+    "web_port": 7444,
+    "manager_port": 7443
+  },
+  "metrics": {
+    "enabled": true,
+    "listen": "internal",
+    "port": 9464,
+    "https_port": 9465,
+    "service_account": "metrics",
+    "otlp_endpoint": "",
+    "otlp_username": "",
+    "otlp_password": "",
+    "keep_details": "24 hours",
+    "keep_hourly": "1 month",
+    "keep_daily": "3 months",
+    "keep_monthly": "1 year",
+    "keep_yearly": "10 years"
  }
 }
@@ -0,0 +1,22 @@
+# Written by vpn-router-setup from /etc/vpn-router/vpn-router.json; edits are overwritten.
+{
+	auto_https disable_redirects
+{%- if https_email %}
+	email {{ https_email }}
+{%- endif %}
+}
+{% if web_enabled %}
+{{ local_fqdn }}:{{ https_web_port }} {
+	reverse_proxy {{ loopback }}:{{ web_port }}
+}
+{% endif %}
+{%- if manager_port %}
+{{ local_fqdn }}:{{ https_manager_port }} {
+	reverse_proxy {{ loopback }}:{{ manager_port }}
+}
+{% endif %}
+{%- if metrics_enabled %}
+{{ local_fqdn }}:{{ metrics_https_port }} {
+	reverse_proxy {{ loopback }}:{{ metrics_port }}
+}
+{% endif %}
@@ -1,46 +0,0 @@
-connections {
-  remote-site {
-    version = 2
-    proposals = aes256-sha256-modp2048,aes256-sha1-modp1024
-    reauth_time = 28800
-    unique = replace
-
-    local_addrs  = {{ local_addrs }}
-    remote_addrs = {{ remote_addrs }}
-
-    local {
-      id = {{ local_id }}
-      auth = psk
-    }
-
-    remote {
-      id = {{ remote_id }}
-      auth = psk
-    }
-
-    children {
-      site2site {
-        mode = tunnel
-        local_ts = {{ local_ts }}
-        remote_ts = {{ remote_cidrs }}
-        esp_proposals = aes256-sha256,aes256-sha1
-        life_time = 3600
-        dpd_action = restart
-        start_action = start
-        close_action = none
-      }
-    }
-
-    rekey_time = 10800
-    dpd_delay = 10
-    dpd_timeout = 120
-  }
-}
-
-secrets {
-  ike-psk {
-    id-1 = {{ local_id }}
-    id-2 = {{ remote_id }}
-    secret = "{{ psk }}"
-  }
-}
@@ -0,0 +1,50 @@
+connections {
+{%- for connection in connections if connection.ready %}
+  {{ connection.name }} {
+    version = 2
+    proposals = aes256-sha256-modp2048,aes256-sha1-modp1024
+    reauth_time = 28800
+    unique = replace
+
+    local_addrs  = {{ local_addrs }}
+    remote_addrs = {{ connection.remote_addrs }}
+
+    local {
+      id = {{ connection.local_id }}
+      auth = psk
+    }
+
+    remote {
+      id = {{ connection.remote_id }}
+      auth = psk
+    }
+
+    children {
+      {{ connection.name }} {
+        mode = tunnel
+        local_ts = {{ connection.local_ts }}
+        remote_ts = {{ connection.remote_cidrs }}
+        esp_proposals = aes256-sha256,aes256-sha1
+        life_time = 3600
+        dpd_action = restart
+        start_action = start
+        close_action = none
+      }
+    }
+
+    rekey_time = 10800
+    dpd_delay = 10
+    dpd_timeout = 120
+  }
+{%- endfor %}
+}
+
+secrets {
+{%- for connection in connections if connection.ready %}
+  ike-psk-{{ connection.name }} {
+    id-1 = {{ connection.local_id }}
+    id-2 = {{ connection.remote_id }}
+    secret = "{{ connection.psk }}"
+  }
+{%- endfor %}
+}
@@ -15,13 +15,17 @@ locals {
    # Contents of /etc/vpn-router/vpn-router.json.
    config = {
      general = { platform = "azure", mode = "auto" }
-      wan     = { local_fqdn = var.local_fqdn, local_id_mode = var.local_id_mode }
-      local   = { cidrs = [for c in split(",", var.local_cidrs) : trimspace(c) if trimspace(c) != ""] }
-      remote = {
-        addrs = [for a in split(",", var.remote_addrs) : trimspace(a) if trimspace(a) != ""]
-        id    = var.remote_id
-        cidrs = local.remote_cidr_list
-        psk   = var.psk
+      wan     = { local_fqdn = var.local_fqdn }
+      local   = { cidrs = local.local_cidr_list }
+      site_to_site = {
+        "remote-site" = {
+          addrs         = [for a in split(",", var.remote_addrs) : trimspace(a) if trimspace(a) != ""]
+          id            = var.remote_id
+          cidrs         = local.remote_cidr_list
+          local_cidrs   = local.local_cidr_list
+          local_id_mode = var.local_id_mode
+          psk           = var.psk
+        }
      }
      p2s       = { enabled = var.p2s_enabled, address_pool = var.p2s_address_pool, ca_name = "VPN Router CA" }
      wireguard = { enabled = var.wireguard_enabled, address = var.wireguard_address, listen_port = var.wireguard_listen_port }
@@ -1,5 +1,6 @@
 locals {
  remote_cidr_list = [for c in split(",", var.remote_cidrs) : trimspace(c) if trimspace(c) != ""]
+  local_cidr_list  = [for c in split(",", var.local_cidrs) : trimspace(c) if trimspace(c) != ""]
 }

 resource "azurerm_route_table" "router" {
@@ -15,13 +15,17 @@ locals {
    # Contents of /etc/vpn-router/vpn-router.json.
    config = {
      general = { platform = "gcp", mode = "auto" }
-      wan     = { local_fqdn = var.local_fqdn, local_id_mode = var.local_id_mode }
-      local   = { cidrs = [for c in split(",", var.local_cidrs) : trimspace(c) if trimspace(c) != ""] }
-      remote = {
-        addrs = [for a in split(",", var.remote_addrs) : trimspace(a) if trimspace(a) != ""]
-        id    = var.remote_id
-        cidrs = local.remote_cidr_list
-        psk   = var.psk
+      wan     = { local_fqdn = var.local_fqdn }
+      local   = { cidrs = local.local_cidr_list }
+      site_to_site = {
+        "remote-site" = {
+          addrs         = [for a in split(",", var.remote_addrs) : trimspace(a) if trimspace(a) != ""]
+          id            = var.remote_id
+          cidrs         = local.remote_cidr_list
+          local_cidrs   = local.local_cidr_list
+          local_id_mode = var.local_id_mode
+          psk           = var.psk
+        }
      }
      p2s       = { enabled = var.p2s_enabled, address_pool = var.p2s_address_pool, ca_name = "VPN Router CA" }
      wireguard = { enabled = var.wireguard_enabled, address = var.wireguard_address, listen_port = var.wireguard_listen_port }
@@ -1,5 +1,6 @@
 locals {
  remote_cidr_list = [for c in split(",", var.remote_cidrs) : trimspace(c) if trimspace(c) != ""]
+  local_cidr_list  = [for c in split(",", var.local_cidrs) : trimspace(c) if trimspace(c) != ""]
 }

 resource "google_compute_route" "to_remote" {
@@ -47,19 +47,22 @@ cat > /etc/vpn-router/vpn-router.json <<EOF
    "internal": "${INTERNAL_INTERFACE}"
  },
  "wan": {
-    "local_fqdn": "${LOCAL_FQDN}",
-    "local_id_mode": "${LOCAL_ID_MODE}"
+    "local_fqdn": "${LOCAL_FQDN}"
  },
  "local": {
    "cidrs": ${LOCAL_CIDRS},
    "int_addr": "${INT_ADDR}",
    "int_gateway_ip": "${INT_GATEWAY_IP}"
  },
-  "remote": {
-    "addrs": ${REMOTE_ADDRS},
-    "id": "${REMOTE_ID}",
-    "cidrs": ${REMOTE_CIDRS},
-    "psk_file": "/etc/vpn-router/psk"
+  "site_to_site": {
+    "remote-site": {
+      "addrs": ${REMOTE_ADDRS},
+      "id": "${REMOTE_ID}",
+      "cidrs": ${REMOTE_CIDRS},
+      "local_cidrs": ${LOCAL_CIDRS},
+      "local_id_mode": "${LOCAL_ID_MODE}",
+      "psk_file": "/etc/vpn-router/psk"
+    }
  },
  "p2s": {
    "enabled": ${P2S_ENABLED},
@@ -1,9 +1,9 @@
 #!/usr/bin/env python3
 """Commit everything, tag the version of the newest changelog entry and push main with the tags.

-The tag is the upstream version of the first entry of debian-package/debian/changelog,
-without the Debian revision: vpn-router (0.5.1-1) is tagged 0.5.1, which starts the
-release workflow.
+The tag is the version of the first entry of debian-package/debian/changelog, without the
+Debian revision 1: vpn-router (0.5.1-1) is tagged 0.5.1 and (0.5.1-2) 0.5.1-2. The tag
+starts the release workflow.
 """

 import argparse
@@ -48,13 +48,14 @@ def summary():


 def version():
-    """The upstream version of the first changelog entry."""
+    """The tag of the first changelog entry: its version, without the Debian revision when that is 1."""
    first = CHANGELOG.read_text(encoding='utf-8').splitlines()[0]
    start, end = first.find('('), first.find(')')
    if start == -1 or end < start:
        sys.exit(f'{CHANGELOG}: the first line has no version: {first}')
    full = first[start + 1:end]
-    return full.rsplit('-', 1)[0] if '-' in full else full
+    upstream, _, revision = full.rpartition('-')
+    return upstream if upstream and revision == '1' else full


 def main():
Author	SHA1	Message	Date
slawek	68ebd541b2	fix: internal service accounts are the router's own, of which the metrics service's is the one at present, and the documentation says what a service account is. Release / release (push) Successful in 13s Details	2026-10-25 18:27:10 +01:00
slawek	f01be41191	fix: service accounts are managed at /service-accounts, not /users, and the internal one of the metrics service is only listed. Release / release (push) Successful in 12s Details	2026-10-25 18:18:03 +01:00
slawek	d1970b77b7	fix: vpn-router-setup owns only the creation of the metrics service's account, which is marked internal, and administrators add service accounts with vpn-router-user add --service and /users. Release / release (push) Successful in 32s Details	2026-10-25 18:00:25 +01:00
slawek	bf651da5a6	update: release.py tags a Debian revision other than 1 as x.y.z-n. Release / release (push) Successful in 19s Details	2026-10-25 17:32:48 +01:00
slawek	4a5b15a559	feature: site_to_site holds any number of named site-to-site connections, which /site-to-site lists, adds, changes and removes. Release / release (push) Successful in 12s Details	2026-10-25 17:14:23 +01:00
slawek	a79510a02f	feature: /config shows the router's PostgreSQL clusters and their settings, and /postgresql their databases with their sizes. Release / release (push) Successful in 28s Details	2026-10-25 15:26:54 +01:00
slawek	38151bf5be	feature: the router keeps its metrics in PostgreSQL, serves them for an OpenTelemetry Collector and pushes them over OTLP. Release / release (push) Successful in 14s Details	2026-10-25 14:57:47 +01:00
slawek	83c1c50d8d	feature: vpn-config-edit shows and changes the router's configuration. Release / release (push) Successful in 19s Details	2026-10-25 13:29:12 +01:00
slawek	650896131d	fix: web.status_content is basic by default. Release / release (push) Successful in 19s Details	2026-10-25 13:09:57 +01:00
slawek	dbc2046e24	feature: the status page shows the Client IP, and web.status_content sets how much it shows. Release / release (push) Successful in 12s Details	2026-10-25 13:08:08 +01:00
slawek	45d73abe7b	feature: Caddy serves the status page and the Router Manager over HTTPS with a certificate from Let's Encrypt. Release / release (push) Successful in 23s Details	2026-10-25 12:25:57 +01:00