feature: bootstrap diagnostics on port 17081 during the first setup.

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

@@ -5,6 +5,12 @@ Regenerates the configuration files first, then does everything that needs
 the live system: routes, DNS-derived identity, WireGuard keys, firewall rules
 and service reloads. Idempotent - a second run changes nothing.
 
+Until a run has succeeded (SETUP_DONE), every run starts the bootstrap
+services, BOOTSTRAP_UNITS, which show the progress and the failure recorded in
+SETUP_STATE on BOOTSTRAP_PORTS, and the firewall opens those ports on the
+internal interface. The first successful run writes SETUP_DONE, closes the
+ports and stops the bootstrap services; a failed run leaves them running.
+
 Interface names come from the configuration and are never guessed. The
 firewall and NAT rules are written against them, so choosing the wrong one
 would be a silent and security-relevant mistake.
@@ -30,9 +36,16 @@ UFW_DEFAULTS = pathlib.Path('/etc/default/ufw')
 WG_DIR       = pathlib.Path('/etc/wireguard')
 WEB_STATE    = pathlib.Path('/run/vpn-router/web.json')
 
-#: The state, the current step and the failure of the last run, which the web service shows while it starts.
+#: The state, the current step and the failure of the last run, which the bootstrap services show.
 SETUP_STATE  = pathlib.Path('/run/vpn-router/setup.json')
 
+#: Written once a run has succeeded; until then setup runs the bootstrap services and opens their ports.
+SETUP_DONE   = pathlib.Path('/var/lib/vpn-router/setup.done')
+
+#: The units of the bootstrap services, and their ports: the Router Manager's and the router's.
+BOOTSTRAP_UNITS = ('vpn-router-bootstrap.service', 'vpn-router-manager-bootstrap.service')
+BOOTSTRAP_PORTS = (17080, 17081)
+
 #: The Router Manager, vpn-router-manager, when it is installed, and its settings.
 MANAGER        = pathlib.Path('/usr/lib/vpn-router-manager/manager')
 MANAGER_CONFIG = pathlib.Path('/etc/vpn-router-manager/manager.json')
@@ -49,6 +62,7 @@ BLOCKS = (
     ('# OPENVPN RULES START',       '# OPENVPN RULES END'),
     ('# P2S DNS RULES START',       '# P2S DNS RULES END'),
     ('# WEB RULES START',           '# WEB RULES END'),
+    ('# BOOTSTRAP RULES START',     '# BOOTSTRAP RULES END'),
     ('# MANAGER RULES START',       '# MANAGER RULES END'),
     ('# ROUTER FORWARD RULES START', '# ROUTER FORWARD RULES END'),
     ('# ROUTER NAT RULES START',    '# ROUTER NAT RULES END'),
@@ -202,6 +216,14 @@ def filter_block(ctx):
             '# WEB RULES END',
         ]
 
+    if not SETUP_DONE.exists() and ctx['int_iface']:
+        lines += [
+            '',
+            '# BOOTSTRAP RULES START',
+            *(f'-A ufw-before-input -i {ctx["int_iface"]} -p tcp --dport {port} -j ACCEPT' for port in BOOTSTRAP_PORTS),
+            '# BOOTSTRAP RULES END',
+        ]
+
     if MANAGER.exists() and ctx['int_iface']:
         port = manager_port()
         lines += [
@@ -448,7 +470,27 @@ def progress(state, step, error=None):
     }) + '\n', encoding='utf-8')
 
 
+def start_bootstrap():
+    """Start the bootstrap services while no run has succeeded; a unit that is not installed is skipped."""
+    if not SETUP_DONE.exists():
+        for unit in BOOTSTRAP_UNITS:
+            run(['systemctl', 'start', '--no-block', unit], check=False)
+
+
+def end_bootstrap(ctx):
+    """After the first successful run: write SETUP_DONE, close the bootstrap ports and stop the bootstrap services."""
+    if SETUP_DONE.exists():
+        return
+    SETUP_DONE.parent.mkdir(parents=True, exist_ok=True)
+    SETUP_DONE.touch()
+    if setup_ufw(ctx):
+        run(['ufw', 'reload'], check=False)
+    for unit in BOOTSTRAP_UNITS:
+        run(['systemctl', 'stop', unit], check=False)
+
+
 def main():
+    start_bootstrap()
     progress('running', 'configuration')
     cfg = vpnrouter.load_config()
     ctx, changed = vpnrouter.configure(cfg)
@@ -511,6 +553,7 @@ def main():
         print(f'vpn-router: error: {problem}', file=sys.stderr)
         return 1
     progress('done', 'done')
+    end_bootstrap(ctx)
     return 0