diff options
| author | Donald Sharp <sharpd@nvidia.com> | 2025-01-31 18:53:30 -0500 |
|---|---|---|
| committer | Mergify <37929162+mergify[bot]@users.noreply.github.com> | 2025-02-01 11:26:53 +0000 |
| commit | ce0d5605591573087d7331a4858453b45244a3bb (patch) | |
| tree | e19bd7d29ddbf905880ac9c1a53e2b9805c287c6 | |
| parent | c49bd1f9a5fdf80b24c25ca6eda83cc8a541a08c (diff) | |
bgpd: With suppress-fib-pending ensure withdrawal is sent
When you have suppress-fib-pending turned on it is possible
to end up in a situation where the prefix is not withdrawn
from downstream peers.
Here is the timing that I believe is happening:
a) have 2 paths to a peer.
b) receive a withdrawal from 1 path, set BGP_NODE_FIB_INSTALL_PENDING
and send the route install to zebra.
c) receive a withdrawal from the other path.
d) At this point we have a dest->flags set BGP_NODE_FIB_INSTALL_PENDING
old_select the path_info going away, new_select is NULL
e) A bit further down we call group_announce_route() which calls
the code to see if we should advertise the path. It sees the
BGP_NODE_FIB_INSTALL_PENDING flag and says, nope.
f) the route is sent to zebra to withdraw, which unsets the
BGP_NODE_FIB_INSTALL_PENDING.
g) This function winds up and deletes the path_info. Dest now
has no path infos.
h) BGP receives the route install(from step b) and unsets the
BGP_NODE_FIB_INSTALL_PENDING flag
i) BGP receives the route removed from zebra (from step f) and
unsets the flag again.
We know if there is no new_select, let's go ahead and just
unset the PENDING flag to allow the withdrawal to go out
at the time when the second withdrawal is received.
Signed-off-by: Donald Sharp <sharpd@nvidia.com>
(cherry picked from commit 4e8eda74ec7d30ba84e7f53f077f4b896728505a)
| -rw-r--r-- | bgpd/bgp_route.c | 6 |
1 files changed, 6 insertions, 0 deletions
diff --git a/bgpd/bgp_route.c b/bgpd/bgp_route.c index 35c9937a06..aa2c3a6a56 100644 --- a/bgpd/bgp_route.c +++ b/bgpd/bgp_route.c @@ -3482,6 +3482,12 @@ static void bgp_process_main_one(struct bgp *bgp, struct bgp_dest *dest, BGP_PATH_ATTR_CHANGED); UNSET_FLAG(new_select->flags, BGP_PATH_MULTIPATH_CHG); UNSET_FLAG(new_select->flags, BGP_PATH_LINK_BW_CHG); + } else { + /* + * Ensure that on uninstall that the INSTALL_PENDING + * is no longer set + */ + UNSET_FLAG(dest->flags, BGP_NODE_FIB_INSTALL_PENDING); } /* call bmp hook for loc-rib route update / withdraw after flags were |