From 374c8dc4dbc8a560036fecdfb3213f690099b869 Mon Sep 17 00:00:00 2001 From: Martin Buck Date: Tue, 4 Mar 2025 14:24:33 +0100 Subject: [PATCH] pimd: Fix PIM6 MLD VRF support (use recvmsg() pktinfo) When receiving MLD messages, prefer pktinfo over msghdr.msg_name for determining the source interface. The latter is just the VRF master interface in case of VRF and we need the true interface the packet was received on instead. Signed-off-by: Martin Buck --- pimd/pim6_mld.c | 27 +++++++++++++++------------ 1 file changed, 15 insertions(+), 12 deletions(-) diff --git a/pimd/pim6_mld.c b/pimd/pim6_mld.c index 2546166d0a..fed75a0a0c 100644 --- a/pimd/pim6_mld.c +++ b/pimd/pim6_mld.c @@ -1770,18 +1770,6 @@ static void gm_t_recv(struct event *t) goto out_free; } - struct interface *ifp; - - ifp = if_lookup_by_index(pkt_src->sin6_scope_id, pim->vrf->vrf_id); - if (!ifp || !ifp->info) - goto out_free; - - struct pim_interface *pim_ifp = ifp->info; - struct gm_if *gm_ifp = pim_ifp->mld; - - if (!gm_ifp) - goto out_free; - for (cmsg = CMSG_FIRSTHDR(mh); cmsg; cmsg = CMSG_NXTHDR(mh, cmsg)) { if (cmsg->cmsg_level != SOL_IPV6) continue; @@ -1800,6 +1788,21 @@ static void gm_t_recv(struct event *t) } } + /* Prefer pktinfo as that also works in case of VRF */ + ifindex_t ifindex = pktinfo ? pktinfo->ipi6_ifindex + : pkt_src->sin6_scope_id; + struct interface *ifp; + + ifp = if_lookup_by_index(ifindex, pim->vrf->vrf_id); + if (!ifp || !ifp->info) + goto out_free; + + struct pim_interface *pim_ifp = ifp->info; + struct gm_if *gm_ifp = pim_ifp->mld; + + if (!gm_ifp) + goto out_free; + if (!pktinfo || !hoplimit) { zlog_err(log_ifp( "BUG: packet without IPV6_PKTINFO or IPV6_HOPLIMIT")); -- 2.39.5