fix: the web service listens on the internal address, the external address or both.

debian-package/src/usr/lib/vpn-router/setup

@@ -215,11 +215,13 @@ def filter_block(ctx):
                 ]
         lines += ['# P2S DNS RULES END']
 
-    if ctx['web_enabled'] and ctx['int_iface']:
+    # The web service and the Router Manager 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 += [
             '',
             '# WEB RULES START',
-            f'-A ufw-before-input -i {ctx["int_iface"]} -p tcp --dport {ctx["web_port"]} -j ACCEPT',
+            *(f'-A ufw-before-input -i {name} -p tcp --dport {ctx["web_port"]} -j ACCEPT' for name in interfaces),
             '# WEB RULES END',
         ]
 
@@ -231,12 +233,12 @@ def filter_block(ctx):
             '# BOOTSTRAP RULES END',
         ]
 
-    if MANAGER.exists() and ctx['int_iface']:
+    if MANAGER.exists() and interfaces:
         port = manager_port()
         lines += [
             '',
             '# MANAGER RULES START',
-            f'-A ufw-before-input -i {ctx["int_iface"]} -p tcp --dport {port} -j ACCEPT',
+            *(f'-A ufw-before-input -i {name} -p tcp --dport {port} -j ACCEPT' for name in interfaces),
             '# MANAGER RULES END',
         ]
 

debian-package/src/usr/lib/vpn-router/vpnrouter.py

@@ -21,7 +21,7 @@ if str(LIB_DIR) not in sys.path:
 
 import vpnrouter_ldap
 import vpnrouter_platforms
-from vpnrouter_net import ConfigError, detect_interfaces, interface_addresses, ip_output
+from vpnrouter_net import DEFAULT_LISTEN, LISTEN_CHOICES, ConfigError, detect_interfaces, interface_addresses, ip_output
 
 CONFIG_FILE  = pathlib.Path('/etc/vpn-router/vpn-router.json')
 TEMPLATE_DIR = pathlib.Path('/usr/share/vpn-router/templates')
@@ -54,7 +54,7 @@ SCHEMA = {
     'wireguard':  {'enabled': False, 'address': '', 'listen_port': 51820},
     'openvpn':    {'enabled': False, 'address_pool': '', 'port': 1194, 'protocol': 'udp'},
     'docker':     {'mode': 'auto', 'exposed_ports': []},
-    'web':        {'enabled': True, 'port': 7081, 'database': '', 'trusted_proxies': []},
+    'web':        {'enabled': True, 'listen': DEFAULT_LISTEN, 'port': 7081, 'database': '', 'trusted_proxies': []},
 }
 
 DOCKER_MODES = ('auto', 'on', 'off')
@@ -259,6 +259,11 @@ def validate(cfg):
     if isinstance(web_port, bool) or not isinstance(web_port, int) or not 1 <= web_port <= 65535:
         raise ConfigError(f'web.port: {web_port!r} is not a valid port')
 
+    web_listen = _get(cfg, 'web', 'listen')
+    if web_listen not in LISTEN_CHOICES:
+        raise ConfigError(
+            f'web.listen: {web_listen!r} is not one of {", ".join(LISTEN_CHOICES)}')
+
     for item in _get_list(cfg, 'web', 'trusted_proxies'):
         _check_address(item, 'web.trusted_proxies')
 

debian-package/src/usr/lib/vpn-router/vpnrouter_net.py

@@ -7,6 +7,12 @@ this module too.
 import pathlib
 import subprocess
 
+#: The values of web.listen and of the Router Manager's listen: the interfaces a service listens on.
+LISTEN_CHOICES = ('internal', 'external', 'both')
+
+#: The interfaces a service listens on when it is not set.
+DEFAULT_LISTEN = 'both'
+
 
 class ConfigError(Exception):
     """A setting is present but malformed."""
@@ -110,26 +116,58 @@ def internal_address(mode, internal, int_addr):
     return addresses[0] if addresses else ''
 
 
-def web_listen(configuration, default_port):
-    """Where the web service listens, from vpn-router.json read as configuration, as ((address, port), '').
+def external_address(mode, external):
+    """The router's address on the external interface, as general.mode directs, or '' when it is not known yet.
 
-    The address is the internal address as general.mode directs, the port web.port, else
-    default_port. While web.enabled is false or the address is not known, the answer is (None,
-    the reason).
+    auto works out which interface that is; the other modes read the address of interfaces.external.
     """
-    def section(name):
-        value = configuration.get(name)
-        return value if isinstance(value, dict) else {}
+    try:
+        if mode == 'auto':
+            external = detect_interfaces()[0]
+        addresses = interface_addresses(external, 'interfaces.external')
+    except ConfigError:
+        return ''
+    return addresses[0] if addresses else ''
 
-    web = section('web')
+
+def _section(configuration, name):
+    """A section of a configuration, or {} when it is missing or not an object."""
+    value = configuration.get(name)
+    return value if isinstance(value, dict) else {}
+
+
+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.
+    """
+    if choice not in LISTEN_CHOICES:
+        choice = DEFAULT_LISTEN
+    general, interfaces, local = (_section(configuration, name) for name in ('general', 'interfaces', 'local'))
+    mode = str(general.get('mode') or 'manual')
+    addresses = []
+    if choice in ('internal', 'both'):
+        addresses.append(internal_address(mode, str(interfaces.get('internal') or ''), str(local.get('int_addr') or '')))
+    if choice in ('external', 'both'):
+        addresses.append(external_address(mode, str(interfaces.get('external') or '')))
+    return [address for address in addresses if address]
+
+
+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).
+    """
+    web = _section(configuration, 'web')
     if web.get('enabled', True) is False:
-        return None, 'the web service is disabled in the configuration'
+        return [], 'the web service is disabled in the configuration'
     port = web.get('port', default_port)
     if isinstance(port, bool) or not isinstance(port, int) or not 1 <= port <= 65535:
         port = default_port
-    general, interfaces, local = section('general'), section('interfaces'), section('local')
-    address = internal_address(str(general.get('mode') or 'manual'), str(interfaces.get('internal') or ''),
-                               str(local.get('int_addr') or ''))
-    if not address:
-        return None, 'the internal address is not known yet'
-    return (address, 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], ''

debian-package/src/usr/lib/vpn-router/vpnrouter_serve.py

@@ -10,31 +10,37 @@ from http.server import ThreadingHTTPServer
 
 
 def serve(wanted, handler, log, interval):
-    """Work out where to listen every interval seconds with wanted, and run an HTTP server of handler there.
+    """Work out where to listen every interval seconds with wanted, and run an HTTP server of handler at each place.
 
-    wanted answers ((address, port), '') or (None, the reason not to listen). When the address or
-    the port changes, the server is stopped and a new one listens at the new place; while there is
-    no place or it cannot be bound, no server runs and the next round tries again. Every new
-    reason is logged with log. Does not return.
+    wanted answers ([(address, port), ...], '') or ([], the reason not to listen). A server whose
+    place is no longer wanted is stopped, and a new one listens at each new place; a place that
+    cannot be bound is tried again the next round. Every new message is logged with log. Does
+    not return.
     """
-    server, thread, listening, reported = None, None, None, None
+    servers, reported = {}, None
     while True:
-        target, reason = wanted()
-        if target != listening and server is not None:
+        targets, reason = wanted()
+        for target in [target for target in servers if target not in targets]:
+            server, thread = servers.pop(target)
             server.shutdown()
             server.server_close()
             thread.join()
-            server, listening = None, None
-        if target is not None and server is None:
+        messages = [reason] if reason else []
+        for target in targets:
+            if target in servers:
+                continue
             try:
                 server = ThreadingHTTPServer(target, handler)
             except OSError as exc:
-                reason = f'cannot listen on {target[0]}:{target[1]}: {exc}'
-            else:
-                thread = threading.Thread(target=server.serve_forever, name='server', daemon=True)
-                thread.start()
-                listening, reason = target, f'serving on http://{target[0]}:{target[1]}'
-        if reason and reason != reported:
-            log(reason)
-            reported = reason
+                messages.append(f'cannot listen on {target[0]}:{target[1]}: {exc}')
+                continue
+            thread = threading.Thread(target=server.serve_forever, name=f'server {target[0]}', daemon=True)
+            thread.start()
+            servers[target] = (server, thread)
+        if servers:
+            messages.append('serving on ' + ', '.join(f'http://{address}:{port}' for address, port in servers))
+        message = '; '.join(messages)
+        if message and message != reported:
+            log(message)
+            reported = message
         time.sleep(interval)

debian-package/src/usr/lib/vpn-router/web

@@ -1,5 +1,5 @@
 #!/usr/bin/python3
-"""Serve the status of the router on its internal address.
+"""Serve the status of the router on its internal address, its external address or both, as web.listen sets.
 
 Run by vpn-router-web.service. Users are managed with vpnrouter_users, the module that
 vpn-router-user uses too.
@@ -27,7 +27,7 @@ token of vpn-router-token has the admin claim and names no user; it may call eve
 add or take out its members, and remove one of its members. These paths and /auth are not
 served (404) while the key does not exist. /auth is limited to AUTH_LIMIT calls per client
 address in AUTH_WINDOW seconds; the address of a call from one of web.trusted_proxies, by
-default the address the service listens on, is the last entry of its X-Forwarded-For header.
+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
@@ -40,10 +40,11 @@ logging each failure. Then it listens. Its unit starts it only once wait-for-lib
 in the linker cache, where psycopg looks it up.
 
 The service needs nothing else to start and does not end on its own. Every DISCOVERY_SECONDS it
-works out the internal address from /etc/vpn-router/vpn-router.json as general.mode directs,
-with web.port and web.enabled (vpnrouter_net.web_listen), and runs the server there
-(vpnrouter_serve.serve): it starts it, moves it when the address or the port changes, and stops
-it while the service is disabled or the address is not known. Every request reads what it needs when it is made: the signing
+works out from /etc/vpn-router/vpn-router.json the addresses of the interfaces web.listen names,
+internal, external or both, as general.mode directs, with web.port and web.enabled
+(vpnrouter_net.web_listen), and runs a server on each (vpnrouter_serve.serve): it starts them,
+moves them when an address or the port changes, and stops them while the service is disabled or
+no address is known. Every request reads what it needs when it is made: the signing
 key, the configuration, and the features of the router and the facts shown by /config from
 /run/vpn-router/web.json, which vpn-router-setup writes. Before setup has written that file
 the router has no features, and /config shows no configuration or interfaces.

debian-package/src/usr/share/doc/vpn-router/vpn-router.json.example

@@ -45,6 +45,7 @@
   },
   "web": {
     "enabled": true,
+    "listen": "both",
     "port": 7081,
     "database": "",
     "trusted_proxies": []