pimd: Process no-forward BSM packet

Topology Used:
=============
Cisco---FRR4----FRR2

Initially PIM nbr is down between FRR4----FRR2 from FRR2 side
Cisco is sending BSR packet to FRR4.

Problem Statement:
=================
No shutdown the PIM neighbor on FRR2 towards FRR4.
FRR2, receives BSR packet immediately as the new neighbor
comes up. This BSR packet is having no-forward bit set.
FRR2 is not able to process the BSR packet, and drop the
BSR packet.

Root Cause:
==========
When PIMD comes up, we start BSM timer for 60 seconds.
Here, the value accept_nofwd_bsm is setting to false.

FRR2, when receives no-forward BSR packet, it is getting
accept_nofwd_bsm value as false.

So, it drops, the no-forward BSM packet.

Fix:
===
Set accept_nofwd_bsm as false after first BSM packet received.

Signed-off-by: Sarita Patra <saritap@vmware.com>
This commit is contained in:
Sarita Patra 2023-04-09 22:30:44 -07:00
parent 48055cc48e
commit 8b462d5579

View File

@ -156,7 +156,6 @@ static void pim_on_bs_timer(struct event *t)
pim_nht_bsr_del(scope->pim, scope->current_bsr);
/* Reset scope zone data */
scope->accept_nofwd_bsm = false;
scope->state = ACCEPT_ANY;
scope->current_bsr = PIMADDR_ANY;
scope->current_bsr_prio = 0;
@ -1364,6 +1363,10 @@ int pim_bsm_process(struct interface *ifp, pim_sgaddr *sg, uint8_t *buf,
}
}
/* BSM packet is seen, so resetting accept_nofwd_bsm to false */
if (pim->global_scope.accept_nofwd_bsm)
pim->global_scope.accept_nofwd_bsm = false;
if (!pim_addr_cmp(sg->grp, qpim_all_pim_routers_addr)) {
/* Multicast BSMs are only accepted if source interface & IP
* match RPF towards the BSR's IP address, or they have