bgpd: add mpls vpn nh label bind cache struct and apis

In the context of the ASBR facing an EBGP neighbor, or
facing an IBGP neighbor where the BGP updates received
are re-advertised with a modified next-hop, a new local
label will be re-advertised too, to replace the original
one.

Create a binding table, in the form of a hash list, from the
original labels to the new labels. Since labels can be the
same on several routers, set the next-hop and the label as
the keys. Add the needed API functions to manage the hash
list.

Signed-off-by: Louis Scalbert <louis.scalbert@6wind.com>
Signed-off-by: Philippe Guibert <philippe.guibert@6wind.com>

diff --git a/bgpd/bgp_mplsvpn.c b/bgpd/bgp_mplsvpn.c
index 6b9373728237572d614b9083fa07682140f2c343..0ac76c48b471e88ae5d1851a0f6896d8db6d430f 100644 (file)
--- a/bgpd/bgp_mplsvpn.c
+++ b/bgpd/bgp_mplsvpn.c
@@ -39,6 +39,9 @@
 #include "bgpd/rfapi/rfapi_backend.h"
 #endif
 
+DEFINE_MTYPE_STATIC(BGPD, MPLSVPN_NH_LABEL_BIND_CACHE,
+                   "BGP MPLSVPN nexthop label bind cache");
+
 /*
  * Definitions and external declarations.
  */
@@ -3860,3 +3863,61 @@ void bgp_vpn_leak_export(struct bgp *from_bgp)
                }
        }
 }
+
+/* The nexthops values are compared to
+ * find in the tree the appropriate cache entry
+ */
+int bgp_mplsvpn_nh_label_bind_cmp(
+       const struct bgp_mplsvpn_nh_label_bind_cache *a,
+       const struct bgp_mplsvpn_nh_label_bind_cache *b)
+{
+       if (prefix_cmp(&a->nexthop, &b->nexthop))
+               return 1;
+       if (a->orig_label > b->orig_label)
+               return 1;
+       if (a->orig_label < b->orig_label)
+               return -1;
+       return 0;
+}
+
+void bgp_mplsvpn_nh_label_bind_free(
+       struct bgp_mplsvpn_nh_label_bind_cache *bmnc)
+{
+       if (bmnc->new_label != MPLS_INVALID_LABEL)
+               bgp_lp_release(LP_TYPE_BGP_L3VPN_BIND, bmnc, bmnc->new_label);
+       bgp_mplsvpn_nh_label_bind_cache_del(
+               &bmnc->bgp_vpn->mplsvpn_nh_label_bind, bmnc);
+       XFREE(MTYPE_MPLSVPN_NH_LABEL_BIND_CACHE, bmnc);
+}
+
+struct bgp_mplsvpn_nh_label_bind_cache *
+bgp_mplsvpn_nh_label_bind_new(struct bgp_mplsvpn_nh_label_bind_cache_head *tree,
+                             struct prefix *p, mpls_label_t orig_label)
+{
+       struct bgp_mplsvpn_nh_label_bind_cache *bmnc;
+
+       bmnc = XCALLOC(MTYPE_MPLSVPN_NH_LABEL_BIND_CACHE,
+                      sizeof(struct bgp_mplsvpn_nh_label_bind_cache));
+       bmnc->new_label = MPLS_INVALID_LABEL;
+       prefix_copy(&bmnc->nexthop, p);
+       bmnc->orig_label = orig_label;
+
+       LIST_INIT(&(bmnc->paths));
+       bgp_mplsvpn_nh_label_bind_cache_add(tree, bmnc);
+
+       return bmnc;
+}
+
+struct bgp_mplsvpn_nh_label_bind_cache *bgp_mplsvpn_nh_label_bind_find(
+       struct bgp_mplsvpn_nh_label_bind_cache_head *tree, struct prefix *p,
+       mpls_label_t orig_label)
+{
+       struct bgp_mplsvpn_nh_label_bind_cache bmnc = {0};
+
+       if (!tree)
+               return NULL;
+       prefix_copy(&bmnc.nexthop, p);
+       bmnc.orig_label = orig_label;
+
+       return bgp_mplsvpn_nh_label_bind_cache_find(tree, &bmnc);
+}

diff --git a/bgpd/bgp_mplsvpn.h b/bgpd/bgp_mplsvpn.h
index 75758edcc2bb4085786cd750352f58ccfcef30c5..5fe64ade486eb9d5a38a3722b042bf3258c64d48 100644 (file)
--- a/bgpd/bgp_mplsvpn.h
+++ b/bgpd/bgp_mplsvpn.h
@@ -325,4 +325,60 @@ extern void vpn_handle_router_id_update(struct bgp *bgp, bool withdraw,
 extern void bgp_vpn_leak_unimport(struct bgp *from_bgp);
 extern void bgp_vpn_leak_export(struct bgp *from_bgp);
 
+extern int
+bgp_mplsvpn_nh_label_bind_cmp(const struct bgp_mplsvpn_nh_label_bind_cache *a,
+                             const struct bgp_mplsvpn_nh_label_bind_cache *b);
+
+/* used to bind a local label to the (label, nexthop) values
+ * from an incoming BGP mplsvpn update
+ */
+struct bgp_mplsvpn_nh_label_bind_cache {
+
+       /* RB-tree entry. */
+       struct bgp_mplsvpn_nh_label_bind_cache_item entry;
+
+       /* The nexthop and the vpn label are the key of the list.
+        * Only received BGP MPLSVPN updates may use that structure.
+        * orig_label is the original label received from the BGP Update.
+        */
+       struct prefix nexthop;
+       mpls_label_t orig_label;
+
+       /* number of mplsvpn path */
+       unsigned int path_count;
+
+       /* back pointer to bgp instance */
+       struct bgp *bgp_vpn;
+
+       /* MPLS label allocated value.
+        * When the next-hop is changed because of 'next-hop-self' or
+        * because it is an eBGP peer, the redistributed orig_label value
+        * is unmodified, unless the 'l3vpn-multi-domain-switching'
+        * is enabled: a new_label value is allocated:
+        * - The new_label value is sent in the advertised BGP update,
+        * instead of the label value.
+        * - An MPLS entry is set to swap <new_label> with <orig_label>.
+        */
+       mpls_label_t new_label;
+
+       /* list of path_vrfs using it */
+       LIST_HEAD(mplsvpn_nh_label_bind_path_lists, bgp_path_info) paths;
+
+       time_t last_update;
+};
+
+DECLARE_RBTREE_UNIQ(bgp_mplsvpn_nh_label_bind_cache,
+                   struct bgp_mplsvpn_nh_label_bind_cache, entry,
+                   bgp_mplsvpn_nh_label_bind_cmp);
+
+void bgp_mplsvpn_nh_label_bind_free(
+       struct bgp_mplsvpn_nh_label_bind_cache *bmnc);
+
+struct bgp_mplsvpn_nh_label_bind_cache *
+bgp_mplsvpn_nh_label_bind_new(struct bgp_mplsvpn_nh_label_bind_cache_head *tree,
+                             struct prefix *p, mpls_label_t orig_label);
+struct bgp_mplsvpn_nh_label_bind_cache *bgp_mplsvpn_nh_label_bind_find(
+       struct bgp_mplsvpn_nh_label_bind_cache_head *tree, struct prefix *p,
+       mpls_label_t orig_label);
+
 #endif /* _QUAGGA_BGP_MPLSVPN_H */

diff --git a/bgpd/bgpd.c b/bgpd/bgpd.c
index ba2985d3041cce4649687517c6d6b77ff29d403d..22f48114d42ffaa91efdf6756f0ed2144359b267 100644 (file)
--- a/bgpd/bgpd.c
+++ b/bgpd/bgpd.c
@@ -3361,6 +3361,8 @@ static struct bgp *bgp_create(as_t *as, const char *name,
                bgp_label_per_nexthop_cache_init(
                        &bgp->mpls_labels_per_nexthop[afi]);
 
+       bgp_mplsvpn_nh_label_bind_cache_init(&bgp->mplsvpn_nh_label_bind);
+
        if (name)
                bgp->name = XSTRDUP(MTYPE_BGP, name);
 

diff --git a/bgpd/bgpd.h b/bgpd/bgpd.h
index 0eb58773d003ee8902730a78ac2204b31c1eb405..d7caf840fdb1874cf56b3ae6f64938a9210e0dac 100644 (file)
--- a/bgpd/bgpd.h
+++ b/bgpd/bgpd.h
@@ -331,6 +331,9 @@ struct as_confed {
        char *as_pretty;
 };
 
+struct bgp_mplsvpn_nh_label_bind_cache;
+PREDECL_RBTREE_UNIQ(bgp_mplsvpn_nh_label_bind_cache);
+
 /* BGP instance structure.  */
 struct bgp {
        /* AS number of this BGP instance.  */
@@ -578,6 +581,9 @@ struct bgp {
        struct bgp_label_per_nexthop_cache_head
                mpls_labels_per_nexthop[AFI_MAX];
 
+       /* Tree for mplsvpn next-hop label bind cache */
+       struct bgp_mplsvpn_nh_label_bind_cache_head mplsvpn_nh_label_bind;
+
        /* Allocate hash entries to store policy routing information
         * The hash are used to host pbr rules somewhere.
         * Actually, pbr will only be used by flowspec