proxmox-mirrors/mirror_frr
1
0
Fork 0
mirror of https://git.proxmox.com/git/mirror_frr synced 2025-08-05 22:07:57 +00:00
Code Issues Actions Packages Projects Releases Wiki Activity

zebra: When processing route_entries ignore unusable routes

Browse Source 
When zebra is processing routes to determine what to send
to the rib, suppose we have two routes (a) a route processed
earlier that none of it's nexthops were active and (b)
a route that has good nexthops but has a worse admin distance.

rib_process, would not relook at (a)'s nexthops because
the ROUTE_ENTRY_CHANGED flag was not true and it would
win when compared to (b) because it's admin distance
was better, leaving us with a state where we would
attempt and fail to install route (a) because it
was not valid.

Modify the code to consider the number of nexthops
we have as a determiner if we can use the route.

Signed-off-by: Donald Sharp <sharpd@nvidia.com>
This commit is contained in:
Donald Sharp 2020-09-30 17:55:44 -04:00
parent 5c18e66208
commit 9d221fac7e
1 changed files with 48 additions and 38 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

86
zebra/zebra_rib.c
View File

@ -1098,46 +1098,56 @@ static void rib_process(struct route_node *rn)
if (CHECK_FLAG(re->status, ROUTE_ENTRY_REMOVED))
continue;
/* Skip unreachable nexthop. */
/* This first call to nexthop_active_update is merely to
* determine if there's any change to nexthops associated
* with this RIB entry. Now, rib_process() can be invoked due
* to an external event such as link down or due to
* next-hop-tracking evaluation. In the latter case,
* a decision has already been made that the NHs have changed.
* So, no need to invoke a potentially expensive call again.
* Further, since the change might be in a recursive NH which
* is not caught in the nexthop_active_update() code. Thus, we
* might miss changes to recursive NHs.
/*
* If the route entry has changed, verify/resolve
* the nexthops associated with the entry.
*
* In any event if we have nexthops that are not active
* then we cannot use this particular route entry so
* skip it.
*/
if (CHECK_FLAG(re->status, ROUTE_ENTRY_CHANGED)
&& !nexthop_active_update(rn, re)) {
if (re->type == ZEBRA_ROUTE_TABLE) {
/* XXX: HERE BE DRAGONS!!!!!
* In all honesty, I have not yet figured out
* what this part does or why the
* ROUTE_ENTRY_CHANGED test above is correct
* or why we need to delete a route here, and
* also not whether this concerns both selected
* and fib route, or only selected
* or only fib
*
* This entry was denied by the 'ip protocol
* table' route-map, we need to delete it */
if (re != old_selected) {
if (IS_ZEBRA_DEBUG_RIB)
zlog_debug(
"%s: %s(%u):%s: imported via import-table but denied by the ip protocol table route-map",
__func__,
VRF_LOGNAME(vrf),
vrf_id, buf);
rib_unlink(rn, re);
} else
SET_FLAG(re->status,
ROUTE_ENTRY_REMOVED);
}
if (CHECK_FLAG(re->status, ROUTE_ENTRY_CHANGED)) {
if (!nexthop_active_update(rn, re)) {
if (re->type == ZEBRA_ROUTE_TABLE) {
/* XXX: HERE BE DRAGONS!!!!!
* In all honesty, I have not yet
* figured out what this part does or
* why the ROUTE_ENTRY_CHANGED test
* above is correct or why we need to
* delete a route here, and also not
* whether this concerns both selected
* and fib route, or only selected
* or only fib
*
* This entry was denied by the 'ip
* protocol
* table' route-map, we need to delete
* it */
if (re != old_selected) {
if (IS_ZEBRA_DEBUG_RIB)
zlog_debug(
"%s: %s(%u):%s: imported via import-table but denied by the ip protocol table route-map",
__func__,
VRF_LOGNAME(
vrf),
vrf_id, buf);
rib_unlink(rn, re);
} else
SET_FLAG(re->status,
ROUTE_ENTRY_REMOVED);
}
continue;
continue;
}
} else {
/*
* If the re has not changed and the nhg we have is
* not usable, then we cannot use this route entry
* for consideration, as that the route will just
* not install if it is selected.
*/
if (!nexthop_group_active_nexthop_num(&re->nhe->nhg))
continue;
}
/* Infinite distance. */