add classless static route support to the forknet dhcp client so that the ipv4.dhcp.static-routes setting works with OCI containers

Signed-off-by: Gwendolyn <[email protected]>

Author: gwenya

cmd/incusd/main_forknet.go

@@ -391,6 +391,21 @@ func (c *cmdForknet) RunDHCP(cmd *cobra.Command, args []string) error {
 		return nil
 	}
 
+	for _, staticRoute := range lease.Offer.ClasslessStaticRoute() {
+		route := &ip.Route{
+			DevName: iface,
+			Route:   staticRoute.Dest.String(),
+			Via:     staticRoute.Router.String(),
+			Family:  ip.FamilyV4,
+		}
+
+		err = route.Add()
+		if err != nil {
+			fmt.Fprintf(os.Stderr, "Giving up on DHCP, couldn't add classless static route to %q: %v\n", iface, err)
+			return nil
+		}
+	}
+
 	// Create PID file.
 	err = os.WriteFile(filepath.Join(args[0], "dhcp.pid"), []byte(fmt.Sprintf("%d", os.Getpid())), 0644)
 	if err != nil {

test/suites/network_dhcp_routes.sh

@@ -13,6 +13,22 @@ test_network_dhcp_routes() {
   incus exec nettest -- ip route list | grep -q "2.3.0.0/16 via 10.13.37.7"
 
   incus delete nettest -f
+
+  if [ -n "${INCUS_OFFLINE:-}" ]; then
+    echo "==> SKIP: Skipping OCI tests as running offline"
+  else
+    ensure_has_localhost_remote "${INCUS_ADDR}"
+
+    incus remote add docker https://docker.io --protocol=oci
+    incus launch docker:alpine nettest --network=inct$$
+
+    incus exec nettest -- ip route list | grep -q "1.2.0.0/16 via 10.13.37.5"
+    incus exec nettest -- ip route list | grep -q "2.3.0.0/16 via 10.13.37.7"
+
+    incus delete -f nettest
+    incus remote remove docker
+  fi
+
   incus network delete inct$$