Re: [PATCH] netlink: Drop nexthop state flags from routes we duplicate

19 Sep 2025

On 18/09/2025 18:33, Stefano Brivio wrote:
...
The kernel doesn't like those (EINVAL) on RTM_NEWROUTE, as they are
flags representing states, not configuration.
Link: https://github.com/containers/podman/discussions/27104
Signed-off-by: Stefano Brivio 
Reviewed-by: Paul Holzinger 
---
  netlink.c | 5 +++++
  1 file changed, 5 insertions(+)

diff --git a/netlink.c b/netlink.c
index 8f82e73..c436780 100644
--- a/netlink.c
+++ b/netlink.c
@@ -565,6 +565,11 @@ int nl_route_dup(int s_src, unsigned int ifi_src,
      if (nh->nlmsg_type != RTM_NEWROUTE)
      	continue;
+		/* nexthop state flags don't apply to freshly created routes,
+		 * and the kernel will refuse our route if they are set.
+		 */
+		rtm->rtm_flags &= ~RTNH_COMPARE_MASK;
+
      for (rta = RTM_RTA(rtm), na = RTM_PAYLOAD(nh); RTA_OK(rta, na);
           rta = RTA_NEXT(rta, na)) {
      	/* RTA_OIF and RTA_MULTIPATH attributes carry the
-- 
Paul Holzinger

    