core: don't configure IP routes unless there are also IP addresses

Since l3cfg rework, NetworkManager tracks IP routes early, not not only
when IP configuration is ready. That means, with `ipv4.method=auto` and
static `ipv4.routes`, then routes are most likely already configured
before the IP address is obtained via DHCP.

That may be desirable in some cases, but for many cases it's probably
wrong.

Instead, only configure the routes (with an ifindex) when we also have
an IP address.

https://bugzilla.redhat.com/show_bug.cgi?id=2102212

https://gitlab.freedesktop.org/NetworkManager/NetworkManager/-/merge_requests/1574

1 files changed, 25 insertions, 1 deletions

diff --git a/src/core/nm-l3cfg.c b/src/core/nm-l3cfg.c
index 4a49c4f8d9..3c2d3ec838 100644
--- a/src/core/nm-l3cfg.c
+++ b/src/core/nm-l3cfg.c
@@ -1188,6 +1188,7 @@ static void
 _commit_collect_routes(NML3Cfg          *self,
                        int               addr_family,
                        NML3CfgCommitType commit_type,
+                       gboolean          any_addrs,
                        GPtrArray       **routes,
                        GPtrArray       **routes_nodev)
 {
@@ -1213,6 +1214,24 @@ _commit_collect_routes(NML3Cfg          *self,
         else {
             nm_assert(NMP_OBJECT_CAST_IP_ROUTE(obj)->ifindex == self->priv.ifindex);
 
+            if (!any_addrs) {
+                /* This is a unicast route (or a similar route, which has an
+                 * ifindex).
+                 *
+                 * However, during this commit we don't plan to configure any
+                 * IP addresses.  With `ipvx.method=manual` that should not be
+                 * possible. More likely, this is because the profile has
+                 * `ipvx.method=auto` and static routes.
+                 *
+                 * Don't configure any such routes before we also have at least
+                 * one IP address.
+                 *
+                 * This code applies to IPv4 and IPv6, however for IPv6 we
+                 * early on configure a link local address, so in practice the
+                 * branch is not taken for IPv6. */
+                continue;
+            }
+
             if (IS_IPv4 && NMP_OBJECT_CAST_IP4_ROUTE(obj)->weight > 0) {
                 /* This route needs to be registered as ECMP route. */
                 nm_netns_ip_route_ecmp_register(self->priv.netns, self, obj);
@@ -4825,7 +4844,12 @@ _l3_commit_one(NML3Cfg              *self,
 
     addresses = _commit_collect_addresses(self, addr_family, commit_type);
 
-    _commit_collect_routes(self, addr_family, commit_type, &routes, &routes_nodev);
+    _commit_collect_routes(self,
+                           addr_family,
+                           commit_type,
+                           nm_g_ptr_array_len(addresses) > 0,
+                           &routes,
+                           &routes_nodev);
 
     route_table_sync =
         self->priv.p->combined_l3cd_commited