bgpd: Refactor bgp_update some for nexthop reachability

The nexthop reachability code was cut-n-pasted 2 times
with just a tiny bit of difference.  If we ever change
that it becomes `fun` to keep them in sync.  Since this
is more important than full on speed of code let's abstract
and get bgp_update() to be a bit easier to maintain.

Signed-off-by: Donald Sharp <sharpd@nvidia.com>

diff --git a/bgpd/bgp_route.c b/bgpd/bgp_route.c
index dbd1c3cf26616021c69b91e19f6100b3036c5d86..b5ef7bd0768c65247c6f05664e18c2c213b42f9c 100644 (file)
--- a/bgpd/bgp_route.c
+++ b/bgpd/bgp_route.c
@@ -4623,6 +4623,60 @@ static bool bgp_accept_own(struct peer *peer, afi_t afi, safi_t safi,
        return false;
 }
 
+static inline void
+bgp_update_nexthop_reachability_check(struct bgp *bgp, struct peer *peer, struct bgp_dest *dest,
+                                     const struct prefix *p, afi_t afi, safi_t safi,
+                                     struct bgp_path_info *pi, struct attr *attr_new,
+                                     const struct prefix *bgp_nht_param_prefix, bool accept_own)
+{
+       bool connected;
+       afi_t nh_afi;
+
+       if (((afi == AFI_IP || afi == AFI_IP6) &&
+            (safi == SAFI_UNICAST || safi == SAFI_LABELED_UNICAST ||
+             (safi == SAFI_MPLS_VPN && pi->sub_type != BGP_ROUTE_IMPORTED))) ||
+           (safi == SAFI_EVPN && bgp_evpn_is_prefix_nht_supported(p))) {
+               if (safi != SAFI_EVPN && peer->sort == BGP_PEER_EBGP &&
+                   peer->ttl == BGP_DEFAULT_TTL &&
+                   !CHECK_FLAG(peer->flags, PEER_FLAG_DISABLE_CONNECTED_CHECK) &&
+                   !CHECK_FLAG(bgp->flags, BGP_FLAG_DISABLE_NH_CONNECTED_CHK))
+                       connected = true;
+               else
+                       connected = false;
+
+               struct bgp *bgp_nexthop = bgp;
+
+               if (pi->extra && pi->extra->vrfleak && pi->extra->vrfleak->bgp_orig)
+                       bgp_nexthop = pi->extra->vrfleak->bgp_orig;
+
+               nh_afi = BGP_ATTR_NH_AFI(afi, pi->attr);
+
+               if (bgp_find_or_add_nexthop(bgp, bgp_nexthop, nh_afi, safi, pi, NULL, connected,
+                                           bgp_nht_param_prefix) ||
+                   CHECK_FLAG(peer->flags, PEER_FLAG_IS_RFAPI_HD)) {
+                       if (accept_own)
+                               bgp_path_info_set_flag(dest, pi, BGP_PATH_ACCEPT_OWN);
+
+                       bgp_path_info_set_flag(dest, pi, BGP_PATH_VALID);
+               } else {
+                       if (BGP_DEBUG(nht, NHT)) {
+                               zlog_debug("%s(%pI4): NH unresolved for existing %pFX pi %p flags 0x%x",
+                                          __func__, (in_addr_t *)&attr_new->nexthop, p, pi,
+                                          pi->flags);
+                       }
+                       bgp_path_info_unset_flag(dest, pi, BGP_PATH_VALID);
+               }
+       } else {
+               /* case mpls-vpn routes with accept-own community
+                * (which have the BGP_ROUTE_IMPORTED subtype)
+                * case other afi/safi not supporting nexthop tracking
+                */
+               if (accept_own)
+                       bgp_path_info_set_flag(dest, pi, BGP_PATH_ACCEPT_OWN);
+               bgp_path_info_set_flag(dest, pi, BGP_PATH_VALID);
+       }
+}
+
 void bgp_update(struct peer *peer, const struct prefix *p, uint32_t addpath_id,
                struct attr *attr, afi_t afi, safi_t safi, int type,
                int sub_type, struct prefix_rd *prd, mpls_label_t *label,
@@ -4638,8 +4692,6 @@ void bgp_update(struct peer *peer, const struct prefix *p, uint32_t addpath_id,
        struct bgp_path_info *new = NULL;
        const char *reason;
        char pfx_buf[BGP_PRD_PATH_STRLEN];
-       int connected = 0;
-       afi_t nh_afi;
        bool force_evpn_import = false;
        safi_t orig_safi = safi;
        struct bgp_labels bgp_labels = {};
@@ -5204,62 +5256,11 @@ void bgp_update(struct peer *peer, const struct prefix *p, uint32_t addpath_id,
                        }
                }
 
+               bgp_update_nexthop_reachability_check(bgp, peer, dest, p, afi, safi, pi, attr_new,
+                                                     bgp_nht_param_prefix, accept_own);
                /* Nexthop reachability check - for unicast and
                 * labeled-unicast.. */
-               if (((afi == AFI_IP || afi == AFI_IP6) &&
-                    (safi == SAFI_UNICAST || safi == SAFI_LABELED_UNICAST ||
-                     (safi == SAFI_MPLS_VPN &&
-                      pi->sub_type != BGP_ROUTE_IMPORTED))) ||
-                   (safi == SAFI_EVPN &&
-                    bgp_evpn_is_prefix_nht_supported(p))) {
-                       if (safi != SAFI_EVPN && peer->sort == BGP_PEER_EBGP
-                           && peer->ttl == BGP_DEFAULT_TTL
-                           && !CHECK_FLAG(peer->flags,
-                                          PEER_FLAG_DISABLE_CONNECTED_CHECK)
-                           && !CHECK_FLAG(bgp->flags,
-                                          BGP_FLAG_DISABLE_NH_CONNECTED_CHK))
-                               connected = 1;
-                       else
-                               connected = 0;
-
-                       struct bgp *bgp_nexthop = bgp;
-
-                       if (pi->extra && pi->extra->vrfleak &&
-                           pi->extra->vrfleak->bgp_orig)
-                               bgp_nexthop = pi->extra->vrfleak->bgp_orig;
-
-                       nh_afi = BGP_ATTR_NH_AFI(afi, pi->attr);
 
-                       if (bgp_find_or_add_nexthop(bgp, bgp_nexthop, nh_afi,
-                                                   safi, pi, NULL, connected,
-                                                   bgp_nht_param_prefix) ||
-                           CHECK_FLAG(peer->flags, PEER_FLAG_IS_RFAPI_HD)) {
-                               if (accept_own)
-                                       bgp_path_info_set_flag(
-                                               dest, pi, BGP_PATH_ACCEPT_OWN);
-
-                               bgp_path_info_set_flag(dest, pi,
-                                                      BGP_PATH_VALID);
-                       } else {
-                               if (BGP_DEBUG(nht, NHT)) {
-                                       zlog_debug("%s(%pI4): NH unresolved for existing %pFX pi %p flags 0x%x",
-                                                  __func__,
-                                                  (in_addr_t *)&attr_new->nexthop,
-                                                  p, pi, pi->flags);
-                               }
-                               bgp_path_info_unset_flag(dest, pi,
-                                                        BGP_PATH_VALID);
-                       }
-               } else {
-                       /* case mpls-vpn routes with accept-own community
-                        * (which have the BGP_ROUTE_IMPORTED subtype)
-                        * case other afi/safi not supporting nexthop tracking
-                        */
-                       if (accept_own)
-                               bgp_path_info_set_flag(dest, pi,
-                                                      BGP_PATH_ACCEPT_OWN);
-                       bgp_path_info_set_flag(dest, pi, BGP_PATH_VALID);
-               }
 
 #ifdef ENABLE_BGP_VNC
                if (safi == SAFI_MPLS_VPN) {
@@ -5361,48 +5362,8 @@ void bgp_update(struct peer *peer, const struct prefix *p, uint32_t addpath_id,
        bgp_path_info_extra_get(new);
        new->extra->labels = bgp_labels_intern(&bgp_labels);
 
-       /* Nexthop reachability check. */
-       if (((afi == AFI_IP || afi == AFI_IP6) &&
-            (safi == SAFI_UNICAST || safi == SAFI_LABELED_UNICAST ||
-             (safi == SAFI_MPLS_VPN &&
-              new->sub_type != BGP_ROUTE_IMPORTED))) ||
-           (safi == SAFI_EVPN && bgp_evpn_is_prefix_nht_supported(p))) {
-               if (safi != SAFI_EVPN && peer->sort == BGP_PEER_EBGP
-                   && peer->ttl == BGP_DEFAULT_TTL
-                   && !CHECK_FLAG(peer->flags,
-                                  PEER_FLAG_DISABLE_CONNECTED_CHECK)
-                   && !CHECK_FLAG(bgp->flags,
-                                  BGP_FLAG_DISABLE_NH_CONNECTED_CHK))
-                       connected = 1;
-               else
-                       connected = 0;
-
-               nh_afi = BGP_ATTR_NH_AFI(afi, new->attr);
-
-               if (bgp_find_or_add_nexthop(bgp, bgp, nh_afi, safi, new, NULL,
-                                           connected, bgp_nht_param_prefix) ||
-                   CHECK_FLAG(peer->flags, PEER_FLAG_IS_RFAPI_HD)) {
-                       if (accept_own)
-                               bgp_path_info_set_flag(dest, new,
-                                                      BGP_PATH_ACCEPT_OWN);
-
-                       bgp_path_info_set_flag(dest, new, BGP_PATH_VALID);
-               } else {
-                       if (BGP_DEBUG(nht, NHT))
-                               zlog_debug("%s(%pI4): NH unresolved", __func__,
-                                          &attr_new->nexthop);
-                       bgp_path_info_unset_flag(dest, new, BGP_PATH_VALID);
-               }
-       } else {
-               /* case mpls-vpn routes with accept-own community
-                * (which have the BGP_ROUTE_IMPORTED subtype)
-                * case other afi/safi not supporting nexthop tracking
-                */
-               if (accept_own)
-                       bgp_path_info_set_flag(dest, new, BGP_PATH_ACCEPT_OWN);
-               bgp_path_info_set_flag(dest, new, BGP_PATH_VALID);
-       }
-
+       bgp_update_nexthop_reachability_check(bgp, peer, dest, p, afi, safi, new, attr_new,
+                                             bgp_nht_param_prefix, accept_own);
        /* If maximum prefix count is configured and current prefix
         * count exeed it.
         */