Adds the ability to route a specific peer's internet traffic through a
connected cell acting as an exit relay.
Cell A side:
- PUT /api/peers/<peer>/route-via {"via_cell": "cellB"} sets route_via
- Updates WG AllowedIPs to include 0.0.0.0/0 for the exit cell peer
- Adds ip rule + ip route in policy table inside cell-wireguard so the
specific peer's traffic egresses via cellB's WG IP
- Sets exit_relay_active on the cell link and pushes use_as_exit_relay=True
to cellB via peer-sync
Cell B side:
- Receives use_as_exit_relay in the peer-sync payload
- Calls apply_cell_rules(..., exit_relay=True) to add FORWARD -o eth0 ACCEPT
- Stores remote_exit_relay_active flag for startup recovery
Startup recovery:
- apply_all_cell_rules passes exit_relay=remote_exit_relay_active (cellB)
- _apply_startup_enforcement reapplies ip rule for each peer with route_via (cellA)
since policy routing rules don't survive container restart
peer_registry gets route_via field with lazy migration.
22 new tests across test_cell_link_manager, test_peer_registry, test_peer_route_via.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
roof
Constantin