bgpd: Ensure v6 LL address is available before establishing peering

There are startup situations where we will attempt to connect to a remote
peer before bgp has received the v6 LL address.  If we do not have this address
we must not allow the connection to come up until we have one available to use
in those situations where we must have a v6 LL address.

Signed-off-by: Donald Sharp <sharpd@nvidia.com>
(cherry picked from commit dac42f2ef5969a4f5378ddaeede31500f0fdeff9)

diff --git a/bgpd/bgp_zebra.c b/bgpd/bgp_zebra.c
index 49f57b5c03104453b92a328c494b0b9f4f6f12f9..121a786e6e8626af1176c602e8fcd5e469974556 100644 (file)
--- a/bgpd/bgp_zebra.c
+++ b/bgpd/bgp_zebra.c
@@ -682,7 +682,7 @@ static int if_get_ipv6_global(struct interface *ifp, struct in6_addr *addr)
        return 0;
 }
 
-static int if_get_ipv6_local(struct interface *ifp, struct in6_addr *addr)
+static bool if_get_ipv6_local(struct interface *ifp, struct in6_addr *addr)
 {
        struct listnode *cnode;
        struct connected *connected;
@@ -694,10 +694,10 @@ static int if_get_ipv6_local(struct interface *ifp, struct in6_addr *addr)
                if (cp->family == AF_INET6)
                        if (IN6_IS_ADDR_LINKLOCAL(&cp->u.prefix6)) {
                                memcpy(addr, &cp->u.prefix6, IPV6_MAX_BYTELEN);
-                               return 1;
+                               return true;
                        }
        }
-       return 0;
+       return false;
 }
 
 static int if_get_ipv4_address(struct interface *ifp, struct in_addr *addr)
@@ -723,6 +723,7 @@ bool bgp_zebra_nexthop_set(union sockunion *local, union sockunion *remote,
 {
        int ret = 0;
        struct interface *ifp = NULL;
+       bool v6_ll_avail = true;
 
        memset(nexthop, 0, sizeof(struct bgp_nexthop));
 
@@ -792,12 +793,20 @@ bool bgp_zebra_nexthop_set(union sockunion *local, union sockunion *remote,
                         * route-map to
                         * specify the global IPv6 nexthop.
                         */
-                       if_get_ipv6_local(ifp, &nexthop->v6_global);
+                       v6_ll_avail =
+                               if_get_ipv6_local(ifp, &nexthop->v6_global);
                        memcpy(&nexthop->v6_local, &nexthop->v6_global,
                               IPV6_MAX_BYTELEN);
                } else
-                       if_get_ipv6_local(ifp, &nexthop->v6_local);
+                       v6_ll_avail =
+                               if_get_ipv6_local(ifp, &nexthop->v6_local);
 
+               /*
+                * If we are a v4 connection and we are not doing unnumbered
+                * not having a v6 LL address is ok
+                */
+               if (!v6_ll_avail && !peer->conf_if)
+                       v6_ll_avail = true;
                if (if_lookup_by_ipv4(&remote->sin.sin_addr, peer->bgp->vrf_id))
                        peer->shared_network = 1;
                else
@@ -823,7 +832,8 @@ bool bgp_zebra_nexthop_set(union sockunion *local, union sockunion *remote,
                                                   remote->sin6.sin6_scope_id,
                                                   peer->bgp->vrf_id);
                        if (direct)
-                               if_get_ipv6_local(ifp, &nexthop->v6_local);
+                               v6_ll_avail = if_get_ipv6_local(
+                                       ifp, &nexthop->v6_local);
                } else
                /* Link-local address. */
                {
@@ -870,7 +880,7 @@ bool bgp_zebra_nexthop_set(union sockunion *local, union sockunion *remote,
 
        /* If we have identified the local interface, there is no error for now.
         */
-       return true;
+       return v6_ll_avail;
 }
 
 static struct in6_addr *