bgpd: Prevent IPv6 routes received via a ibgp session with own ip as nexthop

Prevent IPv6 routes received via a ibgp session with one of its own interface
ip as nexthop from getting installed in the BGP table.

Implemented IPV6 HASH table, where we need to add any ipv6 address as they
gets configured and delete them from the HASH table as the ipv6 addresses
get unconfigured. The above hash table is used to verify if any route learned
via BGP has nexthop which is equal to one of its its connected ipv6 interface.

Signed-off-by: Biswajit Sadhu sadhub@vmware.com

1 files changed, 133 insertions, 0 deletions

diff --git a/bgpd/bgp_nexthop.c b/bgpd/bgp_nexthop.c
index de97b73c7..cf67a3623 100644
--- a/bgpd/bgp_nexthop.c
+++ b/bgpd/bgp_nexthop.c
@@ -47,6 +47,11 @@
 
 DEFINE_MTYPE_STATIC(BGPD, MARTIAN_STRING, "BGP Martian Address Intf String");
 
+static void bgp_ipv6_address_add(struct bgp *bgp, struct connected *ifc,
+					struct prefix *p);
+static void bgp_ipv6_address_del(struct bgp *bgp, struct connected *ifc,
+				struct prefix *p);
+
 char *bnc_str(struct bgp_nexthop_cache *bnc, char *buf, int size)
 {
 	prefix2str(&(bnc->node->p), buf, size);
@@ -379,6 +384,8 @@ void bgp_connected_add(struct bgp *bgp, struct connected *ifc)
 		if (IN6_IS_ADDR_LINKLOCAL(&p.u.prefix6))
 			return;
 
+		bgp_ipv6_address_add(bgp, ifc, addr);
+
 		rn = bgp_node_get(bgp->connected_table[AFI_IP6],
 				  (struct prefix *)&p);
 
@@ -419,6 +426,8 @@ void bgp_connected_delete(struct bgp *bgp, struct connected *ifc)
 		if (IN6_IS_ADDR_LINKLOCAL(&p.u.prefix6))
 			return;
 
+		bgp_ipv6_address_del(bgp, ifc, addr);
+
 		rn = bgp_node_lookup(bgp->connected_table[AFI_IP6],
 				     (struct prefix *)&p);
 	}
@@ -772,3 +781,127 @@ void bgp_scan_finish(struct bgp *bgp)
 		bgp->import_check_table[afi] = NULL;
 	}
 }
+
+static void *bgp_ipv6_address_hash_alloc(void *p)
+{
+	const struct in6_addr *v6addr = (const struct in6_addr *)p;
+	struct bgp_addrv6 *addr;
+
+	addr = XMALLOC(MTYPE_BGP_ADDR, sizeof(struct bgp_addrv6));
+	addr->addrv6 = *v6addr;
+
+	addr->ifp_name_list = list_new();
+	addr->ifp_name_list->del = bgp_address_hash_string_del;
+
+	return addr;
+}
+
+static void bgp_ipv6_address_hash_free(void *data)
+{
+	struct bgp_addrv6 *v6addr = data;
+
+	list_delete(&v6addr->ifp_name_list);
+	XFREE(MTYPE_BGP_ADDR, v6addr);
+}
+
+static unsigned int bgp_ipv6_address_hash_key_make(void *p)
+{
+	const struct bgp_addrv6 *v6 = p;
+
+	return __ipv6_addr_jhash(&v6->addrv6, 0);
+}
+
+static bool bgp_ipv6_address_hash_cmp(const void *p1,
+					const void *p2)
+{
+	const struct bgp_addrv6 *addr1 = p1;
+	const struct bgp_addrv6 *addr2 = p2;
+
+	return(!memcmp(&addr1->addrv6, &addr2->addrv6,
+				sizeof(struct in6_addr)));
+}
+
+void bgp_ipv6_address_init(struct bgp *bgp)
+{
+	bgp->ipv6_address_hash = hash_create(bgp_ipv6_address_hash_key_make,
+						bgp_ipv6_address_hash_cmp,
+						"BGP IPV6 Address Hash");
+}
+
+void bgp_ipv6_address_destroy(struct bgp *bgp)
+{
+	if (bgp->ipv6_address_hash == NULL)
+		return;
+	hash_clean(bgp->ipv6_address_hash,
+			bgp_ipv6_address_hash_free);
+
+	hash_free(bgp->ipv6_address_hash);
+			bgp->ipv6_address_hash = NULL;
+}
+
+static void bgp_ipv6_address_add(struct bgp *bgp, struct connected *ifc,
+					struct prefix *p)
+{
+	struct bgp_addrv6 tmp = {0};
+	struct bgp_addrv6 *addr = NULL;
+	struct listnode *node = NULL;
+	char *name = 0;
+
+	tmp.addrv6 = p->u.prefix6;
+
+	addr = hash_get(bgp->ipv6_address_hash, &tmp,
+			bgp_ipv6_address_hash_alloc);
+	if (!addr)
+		return;
+
+	for (ALL_LIST_ELEMENTS_RO(addr->ifp_name_list, node, name)) {
+		if (strcmp(ifc->ifp->name, name) == 0)
+			break;
+	}
+
+	if (!node) {
+		name = XSTRDUP(MTYPE_MARTIAN_STRING, ifc->ifp->name);
+		listnode_add(addr->ifp_name_list, name);
+	}
+}
+
+
+static void bgp_ipv6_address_del(struct bgp *bgp, struct connected *ifc,
+				struct prefix *p)
+{
+	struct bgp_addrv6 tmp;
+	struct bgp_addrv6 *addr;
+	struct listnode *node;
+	char *name;
+
+
+	tmp.addrv6 = p->u.prefix6;
+
+	addr = hash_lookup(bgp->ipv6_address_hash, &tmp);
+	/* may have been deleted earlier by bgp_interface_down() */
+	if (addr == NULL)
+		return;
+
+	for (ALL_LIST_ELEMENTS_RO(addr->ifp_name_list, node, name)) {
+		if (strcmp(ifc->ifp->name, name) == 0)
+			break;
+	}
+
+	if (node) {
+		list_delete_node(addr->ifp_name_list, node);
+		XFREE(MTYPE_MARTIAN_STRING, name);
+	}
+
+	if (addr->ifp_name_list->count == 0) {
+		hash_release(bgp->ipv6_address_hash, addr);
+		list_delete(&addr->ifp_name_list);
+		XFREE(MTYPE_BGP_ADDR, addr);
+	}
+}
+int bgp_nexthop_self_ipv6(struct bgp *bgp, struct in6_addr *addr)
+{
+	struct bgp_addrv6 tmp;
+
+	tmp.addrv6 = *addr;
+	return (!!hash_lookup(bgp->ipv6_address_hash, &tmp));
+}