From 2b26882d28fb6c28930c97c4ad53d0bc3e1f29d3 Mon Sep 17 00:00:00 2001
From: Daniel Walton <dwalton@cumulusnetworks.com>
Date: Tue, 16 May 2017 17:28:12 +0000
Subject: [PATCH] bgpd: fix nh_afi in bgp_packet_mpattr_start()

Signed-off-by: Daniel Walton <dwalton@cumulusnetworks.com>
---
 bgpd/bgp_attr.c          | 39 +++++++++++++++------------------------
 bgpd/bgp_attr.h          |  4 ++--
 bgpd/bgp_updgrp_packet.c |  7 ++-----
 3 files changed, 19 insertions(+), 31 deletions(-)

diff --git a/bgpd/bgp_attr.c b/bgpd/bgp_attr.c
index 5c444869b4..0eb84bda02 100644
--- a/bgpd/bgp_attr.c
+++ b/bgpd/bgp_attr.c
@@ -2807,13 +2807,26 @@ bgp_attr_parse (struct peer *peer, struct attr *attr, bgp_size_t size,
 }
 
 size_t
-bgp_packet_mpattr_start (struct stream *s, afi_t afi, safi_t safi, afi_t nh_afi,
+bgp_packet_mpattr_start (struct stream *s, struct peer *peer,
+                         afi_t afi, safi_t safi,
 			 struct bpacket_attr_vec_arr *vecarr,
 			 struct attr *attr)
 {
   size_t sizep;
   iana_afi_t pkt_afi;
   safi_t pkt_safi;
+  afi_t nh_afi;
+
+  if (peer_cap_enhe(peer, afi, safi)) {
+    nh_afi = AFI_IP6;
+  } else {
+    if (afi == AFI_L2VPN)
+      nh_afi = AFI_L2VPN;
+    else if (safi == SAFI_LABELED_UNICAST)
+      nh_afi = afi;
+    else
+      nh_afi = BGP_NEXTHOP_AFI_FROM_NHLEN(attr->extra->mp_nexthop_len);
+  }
 
   /* Set extended bit always to encode the attribute length as 2 bytes */
   stream_putc (s, BGP_ATTR_FLAG_OPTIONAL|BGP_ATTR_FLAG_EXTLEN);
@@ -3096,26 +3109,6 @@ bgp_packet_mpattr_end (struct stream *s, size_t sizep)
 }
 
 
-/* Return the Nexthop AFI that should be used */
-afi_t
-bgp_nexthop_afi (struct peer *peer, afi_t afi, safi_t safi, struct attr *attr)
-{
-  afi_t nh_afi;
-
-  if (peer_cap_enhe(peer, afi, safi)) {
-    nh_afi = AFI_IP6;
-  } else {
-    if (afi == AFI_L2VPN)
-      nh_afi = AFI_L2VPN;
-    else if (safi == SAFI_LABELED_UNICAST)
-      nh_afi = afi;
-    else
-      nh_afi = BGP_NEXTHOP_AFI_FROM_NHLEN(attr->extra->mp_nexthop_len);
-  }
-
-  return nh_afi;
-}
-
 /* Make attribute packet. */
 bgp_size_t
 bgp_packet_attribute (struct bgp *bgp, struct peer *peer,
@@ -3132,7 +3125,6 @@ bgp_packet_attribute (struct bgp *bgp, struct peer *peer,
   int send_as4_path = 0;
   int send_as4_aggregator = 0;
   int use32bit = (CHECK_FLAG (peer->cap, PEER_CAP_AS4_RCV)) ? 1 : 0;
-  afi_t nh_afi;
 
   if (! bgp)
     bgp = peer->bgp;
@@ -3145,8 +3137,7 @@ bgp_packet_attribute (struct bgp *bgp, struct peer *peer,
     {
       size_t mpattrlen_pos = 0;
 
-      nh_afi = bgp_nexthop_afi(peer, afi, safi, attr);
-      mpattrlen_pos = bgp_packet_mpattr_start(s, afi, safi, nh_afi, vecarr, attr);
+      mpattrlen_pos = bgp_packet_mpattr_start(s, peer, afi, safi, vecarr, attr);
       bgp_packet_mpattr_prefix(s, afi, safi, p, prd, tag,
                                addpath_encode, addpath_tx_id, attr);
       bgp_packet_mpattr_end(s, mpattrlen_pos);
diff --git a/bgpd/bgp_attr.h b/bgpd/bgp_attr.h
index 2931b2f2b6..e7f3e25c41 100644
--- a/bgpd/bgp_attr.h
+++ b/bgpd/bgp_attr.h
@@ -299,8 +299,8 @@ bgp_attr_flush_encap(struct attr *attr);
  * one for each NLRI that needs to be encoded into the UPDATE message, and
  * finally the _end() function.
  */
-extern size_t bgp_packet_mpattr_start(struct stream *s, afi_t afi, safi_t safi,
-                                      afi_t nh_afi,
+extern size_t bgp_packet_mpattr_start(struct stream *s, struct peer *peer,
+                                      afi_t afi, safi_t safi,
                                       struct bpacket_attr_vec_arr *vecarr,
 				      struct attr *attr);
 extern void bgp_packet_mpattr_prefix(struct stream *s, afi_t afi, safi_t safi,
diff --git a/bgpd/bgp_updgrp_packet.c b/bgpd/bgp_updgrp_packet.c
index 8a4824f859..2408a8ca30 100644
--- a/bgpd/bgp_updgrp_packet.c
+++ b/bgpd/bgp_updgrp_packet.c
@@ -656,7 +656,6 @@ subgroup_update_packet (struct update_subgroup *subgrp)
   u_int32_t addpath_tx_id = 0;
   struct prefix_rd *prd = NULL;
   char label_buf[20];
-  afi_t nh_afi;
 
   if (!subgrp)
     return NULL;
@@ -768,11 +767,9 @@ subgroup_update_packet (struct update_subgroup *subgrp)
           if (bgp_labeled_safi(safi))
             sprintf (label_buf, "label %u", label_pton(tag));
 
-	  if (stream_empty (snlri)) {
-            nh_afi = bgp_nexthop_afi(peer, afi, safi, adv->baa->attr);
-            mpattrlen_pos = bgp_packet_mpattr_start (snlri, afi, safi, nh_afi,
+	  if (stream_empty (snlri))
+            mpattrlen_pos = bgp_packet_mpattr_start (snlri, peer, afi, safi,
                                                      &vecarr, adv->baa->attr);
-          }
 
           bgp_packet_mpattr_prefix (snlri, afi, safi, &rn->p, prd,
                                     tag, addpath_encode, addpath_tx_id, adv->baa->attr);
-- 
2.39.5