bgpd: Respect allowas-in value from the source VRF's peer

If the peer which has allowas-in enabled and then reimports the routes to another
local VRF, respect that value.

This was working with < 10.2 releases.

Fixes: d4426b62d221f4e15810dbe578de05df8991c991 ("bgpd: copy source vrf ASN to leaked route and block loops")

Signed-off-by: Donatas Abraitis <donatas@opensourcerouting.org>
(cherry picked from commit 0dd15189f9783f7b45327111e4334f2208f584f2)

3 files changed, 21 insertions, 19 deletions

diff --git a/bgpd/bgp_mplsvpn.c b/bgpd/bgp_mplsvpn.c
index 5eca5e3e9b..1db65d144a 100644
--- a/bgpd/bgp_mplsvpn.c
+++ b/bgpd/bgp_mplsvpn.c
@@ -1942,7 +1942,7 @@ void vpn_leak_from_vrf_update(struct bgp *to_bgp,	     /* to */
 	 * because of loop checking.
 	 */
 	if (new_info)
-		vpn_leak_to_vrf_update(from_bgp, new_info, NULL);
+		vpn_leak_to_vrf_update(from_bgp, new_info, NULL, path_vrf->peer);
 	else
 		bgp_dest_unlock_node(bn);
 }
@@ -2134,10 +2134,10 @@ static struct bgp *bgp_lookup_by_rd(struct bgp_path_info *bpi,
 	return NULL;
 }
 
-static void vpn_leak_to_vrf_update_onevrf(struct bgp *to_bgp,   /* to */
+static void vpn_leak_to_vrf_update_onevrf(struct bgp *to_bgp,	/* to */
 					  struct bgp *from_bgp, /* from */
-					  struct bgp_path_info *path_vpn,
-					  struct prefix_rd *prd)
+					  struct bgp_path_info *path_vpn, struct prefix_rd *prd,
+					  struct peer *from)
 {
 	const struct prefix *p = bgp_dest_get_prefix(path_vpn->net);
 	afi_t afi = family2afi(p->family);
@@ -2222,6 +2222,12 @@ static void vpn_leak_to_vrf_update_onevrf(struct bgp *to_bgp,   /* to */
 	/* Check if leaked route has our asn. If so, don't import it. */
 	if (CHECK_FLAG(peer->af_flags[afi][SAFI_MPLS_VPN], PEER_FLAG_ALLOWAS_IN))
 		aspath_loop_count = peer->allowas_in[afi][SAFI_MPLS_VPN];
+	else if (peer == peer->bgp->peer_self && from)
+		/* If this is an import from one VRF to another and the source
+		 * VRF's peer has allowas-in applied, respect it.
+		 */
+		aspath_loop_count = from->allowas_in[afi][SAFI_UNICAST];
+
 	if (aspath_loop_check(path_vpn->attr->aspath, to_bgp->as) > aspath_loop_count) {
 		for (bpi = bgp_dest_get_bgp_path_info(bn); bpi;
 		     bpi = bpi->next) {
@@ -2502,9 +2508,8 @@ bool vpn_leak_to_vrf_no_retain_filter_check(struct bgp *from_bgp,
 	return true;
 }
 
-void vpn_leak_to_vrf_update(struct bgp *from_bgp,
-			    struct bgp_path_info *path_vpn,
-			    struct prefix_rd *prd)
+void vpn_leak_to_vrf_update(struct bgp *from_bgp, struct bgp_path_info *path_vpn,
+			    struct prefix_rd *prd, struct peer *peer)
 {
 	struct listnode *mnode, *mnnode;
 	struct bgp *bgp;
@@ -2518,8 +2523,7 @@ void vpn_leak_to_vrf_update(struct bgp *from_bgp,
 	for (ALL_LIST_ELEMENTS(bm->bgp, mnode, mnnode, bgp)) {
 		if (!path_vpn->extra || !path_vpn->extra->vrfleak ||
 		    path_vpn->extra->vrfleak->bgp_orig != bgp) { /* no loop */
-			vpn_leak_to_vrf_update_onevrf(bgp, from_bgp, path_vpn,
-						      prd);
+			vpn_leak_to_vrf_update_onevrf(bgp, from_bgp, path_vpn, prd, peer);
 		}
 	}
 }
@@ -2718,8 +2722,8 @@ void vpn_leak_to_vrf_update_all(struct bgp *to_bgp, struct bgp *vpn_from,
 				    bpi->extra->vrfleak->bgp_orig == to_bgp)
 					continue;
 
-				vpn_leak_to_vrf_update_onevrf(to_bgp, vpn_from,
-							      bpi, NULL);
+				vpn_leak_to_vrf_update_onevrf(to_bgp, vpn_from, bpi, NULL,
+							      bpi->peer);
 			}
 		}
 	}
diff --git a/bgpd/bgp_mplsvpn.h b/bgpd/bgp_mplsvpn.h
index 39fed66781..3b036d2167 100644
--- a/bgpd/bgp_mplsvpn.h
+++ b/bgpd/bgp_mplsvpn.h
@@ -67,9 +67,8 @@ extern bool vpn_leak_to_vrf_no_retain_filter_check(struct bgp *from_bgp,
 						   struct attr *attr,
 						   afi_t afi);
 
-extern void vpn_leak_to_vrf_update(struct bgp *from_bgp,
-				   struct bgp_path_info *path_vpn,
-				   struct prefix_rd *prd);
+extern void vpn_leak_to_vrf_update(struct bgp *from_bgp, struct bgp_path_info *path_vpn,
+				   struct prefix_rd *prd, struct peer *peer);
 
 extern void vpn_leak_to_vrf_withdraw(struct bgp_path_info *path_vpn);
 
diff --git a/bgpd/bgp_route.c b/bgpd/bgp_route.c
index a87cd21f22..165fd07a35 100644
--- a/bgpd/bgp_route.c
+++ b/bgpd/bgp_route.c
@@ -5290,7 +5290,7 @@ void bgp_update(struct peer *peer, const struct prefix *p, uint32_t addpath_id,
 		}
 		if ((SAFI_MPLS_VPN == safi)
 		    && (bgp->inst_type == BGP_INSTANCE_TYPE_DEFAULT)) {
-			vpn_leak_to_vrf_update(bgp, pi, prd);
+			vpn_leak_to_vrf_update(bgp, pi, prd, peer);
 		}
 
 #ifdef ENABLE_BGP_VNC
@@ -5424,7 +5424,7 @@ void bgp_update(struct peer *peer, const struct prefix *p, uint32_t addpath_id,
 	}
 	if ((SAFI_MPLS_VPN == safi)
 	    && (bgp->inst_type == BGP_INSTANCE_TYPE_DEFAULT)) {
-		vpn_leak_to_vrf_update(bgp, new, prd);
+		vpn_leak_to_vrf_update(bgp, new, prd, peer);
 	}
 #ifdef ENABLE_BGP_VNC
 	if (SAFI_MPLS_VPN == safi) {
@@ -6937,8 +6937,7 @@ void bgp_static_update(struct bgp *bgp, const struct prefix *p,
 
 			if (SAFI_MPLS_VPN == safi &&
 			    bgp->inst_type == BGP_INSTANCE_TYPE_DEFAULT) {
-				vpn_leak_to_vrf_update(bgp, pi,
-						       &bgp_static->prd);
+				vpn_leak_to_vrf_update(bgp, pi, &bgp_static->prd, NULL);
 			}
 #ifdef ENABLE_BGP_VNC
 			if (safi == SAFI_MPLS_VPN || safi == SAFI_ENCAP ||
@@ -7002,7 +7001,7 @@ void bgp_static_update(struct bgp *bgp, const struct prefix *p,
 
 	if (SAFI_MPLS_VPN == safi &&
 	    bgp->inst_type == BGP_INSTANCE_TYPE_DEFAULT) {
-		vpn_leak_to_vrf_update(bgp, new, &bgp_static->prd);
+		vpn_leak_to_vrf_update(bgp, new, &bgp_static->prd, NULL);
 	}
 #ifdef ENABLE_BGP_VNC
 	if (safi == SAFI_MPLS_VPN || safi == SAFI_ENCAP || safi == SAFI_EVPN)