[Link-local]IPv4 routes with link local next hops are not installed in the hardware

[dgsudharsan]

Description

IPv4 route with link local nexthop is not installed in the hardware. Previously a similar issue was raised #8606 which was fixed by supporting IPv4 link local nexthops sonic-net/sonic-swss#1903

However a change was introduced to ignore IPv4 link local next hops for dual ToR scenario. sonic-net/sonic-swss#2260. Due to this the nexthop is not resolved and thus the routes are not programmed in the hardware.

127.0.0.1:6379> hgetall "ROUTE_TABLE:10.0.0.22/31"

1. "nexthop"
2. "169.254.0.1"
3. "ifname"
4. "Ethernet8"

127.0.0.1:6379> keys NEIGH

1. "NEIGH_TABLE:eth0:10.9.74.2"
2. "NEIGH_RESOLVE_TABLE:Ethernet8:169.254.0.1"
3. "NEIGH_TABLE:eth0:10.9.74.1"
4. "NEIGH_TABLE:Ethernet8:fe80::268a:7ff:fed0:d40"
   127.0.0.1:6379> hgetall "NEIGH_RESOLVE_TABLE:Ethernet8:169.254.0.1"
5. "mac"
6. "00:00:00:00:00:00"

Steps to reproduce the issue:

1. Enable IPv6 link local.
2. Configure BGP unnumbered.
3. Exchange IPv4 routes
4. Check ASIC DB for the routes

Describe the results you received:

Routes are not pushed to ASIC DB

Describe the results you expected:

Routes with IPv4 link local next hop should be pushed to ASIC DB

Output of show version:

SONiC Software Version: SONiC.202205_rc.4-57a4487c1_Internal
Distribution: Debian 11.4
Kernel: 5.10.0-12-2-amd64
Build commit: 57a4487c1
Build date: Tue Aug 16 15:50:37 UTC 2022
Built by: sw-r2d2-bot@r-build-sonic-ci02-242

Platform: x86_64-mlnx_msn2700-r0
HwSKU: Mellanox-SN2700
ASIC: mellanox
ASIC Count: 1
Serial Number: MT1623X09522
Model Number: MSN2700-CS2FO
Hardware Revision: Not Specified
Uptime: 01:01:37 up  1:43,  1 user,  load average: 0.77, 1.00, 1.19
Date: Wed 24 Aug 2022 01:01:37

Docker images:
REPOSITORY                                         TAG                              IMAGE ID       SIZE
docker-orchagent                                   202205_rc.4-57a4487c1_Internal   48f4b29e69d5   471MB
docker-orchagent                                   latest                           48f4b29e69d5   471MB
docker-teamd                                       202205_rc.4-57a4487c1_Internal   eac1405feb6d   453MB
docker-teamd                                       latest                           eac1405feb6d   453MB
docker-macsec                                      latest                           51e17826801b   455MB
docker-syncd-mlnx                                  202205_rc.4-57a4487c1_Internal   258e52fd636a   852MB
docker-syncd-mlnx                                  latest                           258e52fd636a   852MB
docker-platform-monitor                            202205_rc.4-57a4487c1_Internal   200612bf0d92   855MB
docker-platform-monitor                            latest                           200612bf0d92   855MB
docker-dhcp-relay                                  latest                           853d6573b194   446MB
docker-sonic-telemetry                             202205_rc.4-57a4487c1_Internal   ff9f643ccb64   517MB
docker-sonic-telemetry                             latest                           ff9f643ccb64   517MB
docker-lldp                                        202205_rc.4-57a4487c1_Internal   6980e1ff8957   479MB
docker-lldp                                        latest                           6980e1ff8957   479MB
docker-router-advertiser                           202205_rc.4-57a4487c1_Internal   35ce72cf8303   437MB
docker-router-advertiser                           latest                           35ce72cf8303   437MB
docker-mux                                         202205_rc.4-57a4487c1_Internal   15db5848b5cc   485MB
docker-mux                                         latest                           15db5848b5cc   485MB
docker-database                                    202205_rc.4-57a4487c1_Internal   64bbd239a40b   437MB
docker-database                                    latest                           64bbd239a40b   437MB
docker-fpm-frr                                     202205_rc.4-57a4487c1_Internal   3c05c46e549a   454MB
docker-fpm-frr                                     latest                           3c05c46e549a   454MB
docker-nat                                         202205_rc.4-57a4487c1_Internal   cecffd854283   428MB
docker-nat                                         latest                           cecffd854283   428MB
docker-sflow                                       202205_rc.4-57a4487c1_Internal   ca7041480a31   426MB
docker-sflow                                       latest                           ca7041480a31   426MB
docker-snmp                                        202205_rc.4-57a4487c1_Internal   c6aebe0f5a5f   454MB
docker-snmp                                        latest                           c6aebe0f5a5f   454MB
docker-sonic-mgmt-framework                        202205_rc.4-57a4487c1_Internal   de015d307366   554MB
docker-sonic-mgmt-framework                        latest                           de015d307366   554MB
urm.nvidia.com/sw-nbu-sws-sonic-docker/sonic-wjh   1.3.0-202205-internal-15         41137495f1a6   490MB

Output of show techsupport:

(paste your output here or download and attach the file here )

Additional information you deem important (e.g. issue happens only occasionally):

[prsunny]

@Ndancejic , can you please provide a fix for this. Please check if the subtype is 'dualtor' and ignore the LL neighbor entry.

[Ndancejic]

sonic-net/sonic-swss#2427 <- PR to fix, please review. Thanks!

[zhangyanzhao]

fix PR is merged and close.