zebra: vlan to dplane Offload from main

Trigger: Zebra core seen when we convert l2vni to l3vni and back

BackTrace:
/usr/lib/x86_64-linux-gnu/frr/libfrr.so.0(_zlog_assert_failed+0xe9) [0x7f4af96989d9]
/usr/lib/frr/zebra(zebra_vxlan_if_vni_up+0x250) [0x5561022ae030]
/usr/lib/frr/zebra(netlink_vlan_change+0x2f4) [0x5561021fd354]
/usr/lib/frr/zebra(netlink_parse_info+0xff) [0x55610220d37f]
/usr/lib/frr/zebra(+0xc264a) [0x55610220d64a]
/usr/lib/x86_64-linux-gnu/frr/libfrr.so.0(thread_call+0x7d) [0x7f4af967e96d]
/usr/lib/x86_64-linux-gnu/frr/libfrr.so.0(frr_run+0xe8) [0x7f4af9637588]
/usr/lib/frr/zebra(main+0x402) [0x5561021f4d32]
/lib/x86_64-linux-gnu/libc.so.6(+0x2724a) [0x7f4af932624a]
/lib/x86_64-linux-gnu/libc.so.6(__libc_start_main+0x85) [0x7f4af9326305]
/usr/lib/frr/zebra(_start+0x21) [0x5561021f72f1]

Root Cause:
In working case,
 - We get a RTM_NEWLINK whose ctx is enqueued by zebra dplane and
   dequeued by zebra main and processed i.e.
   (102000 is deleted from vxlan99) before we handle RTM_NEWVLAN.
 - So in handling of NEWVLAN (vxlan99) we bail out since find with
   vlan id 703 does not exist.

root@leaf2:mgmt:/var/log/frr# cat ~/raja_logs/working/nocras.log  | grep "RTM_NEWLINK\|QUEUED\|vxlan99\|in thread"
2024/07/18 23:09:33.741105 ZEBRA: [KMXEB-K771Y] netlink_parse_info: netlink-dp-in (NS 0) type RTM_NEWLINK(16), len=616, seq=0, pid=0
2024/07/18 23:09:33.744061 ZEBRA: [K8FXY-V65ZJ] Intf dplane ctx 0x7f2244000cf0, op INTF_INSTALL, ifindex (65), result QUEUED
2024/07/18 23:09:33.767240 ZEBRA: [KMXEB-K771Y] netlink_parse_info: netlink-dp-in (NS 0) type RTM_NEWLINK(16), len=508, seq=0, pid=0
2024/07/18 23:09:33.767380 ZEBRA: [K8FXY-V65ZJ] Intf dplane ctx 0x7f2244000cf0, op INTF_INSTALL, ifindex (73), result QUEUED
2024/07/18 23:09:33.767389 ZEBRA: [NVFT0-HS1EX] INTF_INSTALL for vxlan99(73)
2024/07/18 23:09:33.767404 ZEBRA: [TQR2A-H2RFY] Vlan-Vni(1186:1186-6000002:6000002) update for VxLAN IF vxlan99(73)
2024/07/18 23:09:33.767422 ZEBRA: [TP4VP-XZ627] Del L2-VNI 102000 intf vxlan99(73)
2024/07/18 23:09:33.767858 ZEBRA: [QYXB9-6RNNK] RTM_NEWVLAN bridge IF vxlan99 NS 0
2024/07/18 23:09:33.767866 ZEBRA: [KKZGZ-8PCDW] Cannot find VNI for VID (703) IF vxlan99 for vlan state update >>>>BAIL OUT

In failure case,
 - The NEWVLAN is received first even before processing RTM_NEWLINK.
 - Since the vxlan id 102000 is not removed from the vxlan99,
   the find with vlan id 703 returns the 102000 one and we invoke
   zebra_vxlan_if_vni_up where the interfaces don't match and assert.

root@leaf2:mgmt:/var/log/frr# cat ~/raja_logs/noworking/crash.log | grep "RTM_NEWLINK\|QUEUED\|vxlan99\|in thread"
2024/07/18 22:26:43.829370 ZEBRA: [KMXEB-K771Y] netlink_parse_info: netlink-dp-in (NS 0) type RTM_NEWLINK(16), len=616, seq=0, pid=0
2024/07/18 22:26:43.829646 ZEBRA: [K8FXY-V65ZJ] Intf dplane ctx 0x7fe07c026d30, op INTF_INSTALL, ifindex (65), result QUEUED
2024/07/18 22:26:43.853930 ZEBRA: [QYXB9-6RNNK] RTM_NEWVLAN bridge IF vxlan99 NS 0
2024/07/18 22:26:43.853949 ZEBRA: [K61WJ-XQQ3X] Intf vxlan99(73) L2-VNI 102000 is UP >>> VLAN PROCESSED BEFORE INTF EVENT
2024/07/18 22:26:43.853951 ZEBRA: [SPV50-BX2RP] RAJA zevpn_vxlanif vxlan48 and ifp vxlan99
2024/07/18 22:26:43.854005 ZEBRA: [KMXEB-K771Y] netlink_parse_info: netlink-dp-in (NS 0) type RTM_NEWLINK(16), len=508, seq=0, pid=0
2024/07/18 22:26:43.854241 ZEBRA: [KMXEB-K771Y] netlink_parse_info: netlink-dp-in (NS 0) type RTM_NEWLINK(16), len=516, seq=0, pid=0
2024/07/18 22:26:43.854251 ZEBRA: [KMXEB-K771Y] netlink_parse_info: netlink-dp-in (NS 0) type RTM_NEWLINK(16), len=544, seq=0, pid=0
ZEBRA: in thread kernel_read scheduled from zebra/kernel_netlink.c:505 kernel_read()

Fix:
Similar to #13396, where link change
handling was offloaded to dplane, same is being done for vlan events.

Note: Prior to this change, zebra main thread was interested in the
RTNLGRP_BRVLAN. So all the kernel events pertaining to vlan was
handled by zebra main.

With this change change as well the handling of vlan events is still
with Zebra main. However we offload it via Dplane thread.

Ticket :#3878175

Signed-off-by: Rajasekar Raja <rajasekarr@nvidia.com>

1 files changed, 1 insertions, 0 deletions

diff --git a/zebra/kernel_socket.c b/zebra/kernel_socket.c
index 5cfbe7a896..4789cb62f2 100644
--- a/zebra/kernel_socket.c
+++ b/zebra/kernel_socket.c
@@ -1627,6 +1627,7 @@ void kernel_update_multi(struct dplane_ctx_list_head *ctx_list)
 		case DPLANE_OP_INTF_ADDR_DEL:
 		case DPLANE_OP_STARTUP_STAGE:
 		case DPLANE_OP_SRV6_ENCAP_SRCADDR_SET:
+		case DPLANE_OP_VLAN_INSTALL:
 			zlog_err("Unhandled dplane data for %s",
 				 dplane_op2str(dplane_ctx_get_op(ctx)));
 			res = ZEBRA_DPLANE_REQUEST_FAILURE;