mirror of
https://gitlab.freedesktop.org/NetworkManager/NetworkManager.git
synced 2026-04-04 15:30:41 +02:00
Kernel does not allow to add the same route (as determined by network/plen,metric) on two different interfaces (ifindex). In case of conflict, NMRouteManager used to ignore any but the firstly added route. On the other hand, we cannot add a gateway-route, if there is no direct route to the gateway. Hence, skipping duplicate routes can mean that we skip a direct route what was necessary to add another gateway-route, which then leads to a failure to add that route. This also applies to IPv4 device routes that since recently are managed by NMRouteManager. For example, say you connect two interfaces to the same IP subnet. The route-metric can conflict if the interfaces are of the same type or if the user explicitly configured a conflict. In case of conflicts, NMRouteManager would only configure the first appearing route and skip the shadowed route on the second interface. Now we cannot configure gateway-routes on the second interface because the gateway is unreachable. There are many scenarios where this issue can happen, especially with default-routes and user-configured-routes. For example with default-routes, ip4_config_merge_and_apply() would check if the default-gateway requires an explict route and possibly add it. But then NMRouteManager might not add the route because it is shadowed by a route on an other interface. This patch solves the issue by having NMRouteManager configure shadowed routes too, similar to what NMDefaultRouteManager does. It does that by searching for an unused, non-conflicting, higher metric for the route, i.e. bump the metric by 1 until we can add it without conflict. Also note that NMRouteManager still ensures that for conflicting routes the best route sticks to the interface that configured it first. That means if you later add the conflicting route on another interface, it will be added with higher metric and the data is still routed along the first interface. |
||
|---|---|---|
| .. | ||
| config | ||
| Makefile.am | ||
| test-dcb.c | ||
| test-general-with-expect.c | ||
| test-general.c | ||
| test-ip4-config.c | ||
| test-ip6-config.c | ||
| test-resolvconf-capture.c | ||
| test-route-manager.c | ||
| test-secret-agent.py | ||
| test-wired-defname.c | ||