interface-ip: always override downstream IPv6 mtu

[oweals/netifd.git] / interface-ip.c

diff --git a/interface-ip.c b/interface-ip.c
index b577e66db5b720a00db09dca55903c9fec2f38d8..b7c1807eb1b0bc394943013f17cb8fba8b23058d 100644 (file)
--- a/interface-ip.c
+++ b/interface-ip.c
@@ -849,8 +849,11 @@ interface_set_prefix_address(struct device_prefix_assignment *assignment,
                        int mtu = system_update_ipv6_mtu(uplink->l3_dev.dev, 0);
                        int mtu_old = system_update_ipv6_mtu(l3_downlink, 0);
 
-                       if (mtu > 0 && mtu_old > mtu)
-                               system_update_ipv6_mtu(l3_downlink, mtu);
+                       if (mtu > 0 && mtu_old != mtu) {
+                               if (system_update_ipv6_mtu(l3_downlink, mtu) < 0)
+                                       netifd_log_message(L_WARNING, "Failed to set IPv6 mtu to %d"
+                                                       "on interface '%s'\n", mtu, iface->name);
+                       }
                }
 
                assignment->enabled = true;