FRR patches to support IPv6 Link local enhancements. (#5584)

As per HLD - Azure/SONiC#625

FRR Patches:

0009-Link-local-scope-was-not-set-while-binding-socket-for-bgp-ipv6-link-local-neighbors.patch
Files modified : bgpd_network.c and bgpd/bgp_zebra.c
Fix for : Link local scope was not set while binding socket with local address causing socket errors for bgp ipv6 link local neighbors.

0010-VRF-interface-lookup-was-still-done-in-the-default-vrf.patch
Files modified : staticd/static_zebra.c
Fix for : VRF interface lookup was still done in the default-vrf which was causing the interface lookup to fail. Due to this static-route pointing to link-local was not getting installed.

0011-Changes-to-send-ipv6-link-local-address-as-nexthop-to-fpmsyncd.patch
Files modified : zebra/zebra_fpm_netlink.c
Fix for : Made changes to send ipv6 address as nexthop to fpmsyncd.

Depends on:
Azure/sonic-utilities#1159
Azure/sonic-swss#1463

Signed-off-by: Akhilesh Samineni akhilesh.samineni@broadcom.com

src/sonic-frr/patch/0009-Link-local-scope-was-not-set-while-binding-socket-for-bgp-ipv6-link-local-neighbors.patch

@@ -0,0 +1,44 @@
+From 4b45abcdb107c8c5d58fd63a2616c54c800305b3 Mon Sep 17 00:00:00 2001
+From: Akhilesh Samineni <akhilesh.samineni@broadcom.com>
+Date: Mon, 5 Apr 2021 13:21:40 -0700
+Subject: [PATCH] Link local scope was not set while binding socket with local
+ address causing socket errors for bgp ipv6 link local neighbors.
+
+---
+ bgpd/bgp_network.c | 5 +++++
+ bgpd/bgp_zebra.c   | 3 +++
+ 2 files changed, 8 insertions(+)
+
+diff --git a/bgpd/bgp_network.c b/bgpd/bgp_network.c
+index 6a5c2c4b3..d7047a154 100644
+--- a/bgpd/bgp_network.c
++++ b/bgpd/bgp_network.c
+@@ -556,6 +556,11 @@ static int bgp_update_address(struct interface *ifp, const union sockunion *dst,
+ 		return 1;
+ 
+ 	prefix2sockunion(sel, addr);
++
++        if (IN6_IS_ADDR_LINKLOCAL(&addr->sin6.sin6_addr)) {
++                addr->sin6.sin6_scope_id = ifp->ifindex;
++        }
++
+ 	return 0;
+ }
+ 
+diff --git a/bgpd/bgp_zebra.c b/bgpd/bgp_zebra.c
+index e42d6ee26..8e9fa8903 100644
+--- a/bgpd/bgp_zebra.c
++++ b/bgpd/bgp_zebra.c
+@@ -814,6 +814,9 @@ bool bgp_zebra_nexthop_set(union sockunion *local, union sockunion *remote,
+ 								? peer->conf_if
+ 								: peer->ifname,
+ 							peer->bgp->vrf_id);
++			else if (peer->update_if)
++				ifp = if_lookup_by_name(peer->update_if,
++						peer->bgp->vrf_id);
+ 		} else if (peer->update_if)
+ 			ifp = if_lookup_by_name(peer->update_if,
+ 						peer->bgp->vrf_id);
+-- 
+2.18.0
+

src/sonic-frr/patch/series

@@ -6,3 +6,4 @@
 0007-frr-remove-frr-log-outchannel-to-var-log-frr.log.patch
 0008-Add-support-of-bgp-l3vni-evpn.patch
 0009-Add-bgp-bestpath-peer-type-multipath-relax.patch
+0009-Link-local-scope-was-not-set-while-binding-socket-for-bgp-ipv6-link-local-neighbors.patch