+ uint16_t attr_len;
+ uint16_t unreach_len = 0;
+ char *unreach_len_pos;
+ uint8_t reach_len;
+ uint16_t len = sizeof(peer->outbuf->packet.header);
+ struct bgp_route6_list *have = peer->routes6;
+ struct bgp_route6_list *want = peer->routing ? bgp_routes6 : 0;
+ struct bgp_route6_list *e = 0;
+ struct bgp_route6_list *add = 0;
+ int s;
+ char ipv6addr[INET6_ADDRSTRLEN];
+
+ char *data = (char *) &peer->outbuf->packet.data;
+
+ /* need leave room for attr_len, bgp_path_attrs and one prefix */
+ char *max = (char *) &peer->outbuf->packet.data
+ + sizeof(peer->outbuf->packet.data)
+ - sizeof(attr_len) - peer->path_attr_len_without_nexthop
+ - BGP_PATH_ATTR_MP_REACH_NLRI_PARTIAL_SIZE - sizeof(struct bgp_ip6_prefix);
+
+ memset(peer->outbuf->packet.header.marker, 0xff,
+ sizeof(peer->outbuf->packet.header.marker));
+
+ peer->outbuf->packet.header.type = BGP_MSG_UPDATE;
+
+ /* insert non-MP unfeasible routes length */
+ memcpy(data, &unreach_len, sizeof(unreach_len));
+ /* skip over it and attr_len too; it will be filled when known */
+ data += sizeof(unreach_len) + sizeof(attr_len);
+ len += sizeof(unreach_len) + sizeof(attr_len);
+
+ /* copy usual attributes */
+ memcpy(data, peer->path_attrs, peer->path_attr_len_without_nexthop);
+ data += peer->path_attr_len_without_nexthop;
+ attr_len = peer->path_attr_len_without_nexthop;
+
+ /* copy MP unreachable NLRI heading */
+ memcpy(data, peer->mp_unreach_nlri_partial,
+ BGP_PATH_ATTR_MP_UNREACH_NLRI_PARTIAL_SIZE);
+ /* remember where to update this attr len */
+ unreach_len_pos = data + 2;
+ data += BGP_PATH_ATTR_MP_UNREACH_NLRI_PARTIAL_SIZE;
+ attr_len += BGP_PATH_ATTR_MP_UNREACH_NLRI_PARTIAL_SIZE;
+
+ peer->update_routes6 = 0; /* tentatively clear */
+
+ /* find differences */
+ while ((have || want) && data < (max - sizeof(struct bgp_ip6_prefix)))
+ {
+ if (have)
+ s = want
+ ? memcmp(&have->dest, &want->dest, sizeof(have->dest))
+ : -1;
+ else
+ s = 1;
+
+ if (s < 0) /* found one to delete */
+ {
+ struct bgp_route6_list *tmp = have;
+ have = have->next;
+
+ s = BGP_IP_PREFIX_SIZE(tmp->dest);
+ memcpy(data, &tmp->dest, s);
+ data += s;
+ unreach_len += s;
+ attr_len += s;
+
+ LOG(5, 0, 0, "Withdrawing route %s/%d from BGP peer %s\n",
+ inet_ntop(AF_INET6, &tmp->dest.prefix, ipv6addr, INET6_ADDRSTRLEN),
+ tmp->dest.len, peer->name);
+
+ free(tmp);
+
+ if (e)
+ e->next = have;
+ else
+ peer->routes6 = have;
+ }
+ else
+ {
+ if (!s) /* same */
+ {
+ e = have; /* stash the last found to relink above */
+ have = have->next;
+ want = want->next;
+ }
+ else if (s > 0) /* addition reqd. */
+ {
+ if (add)
+ {
+ peer->update_routes6 = 1; /* only one add per packet */
+ if (!have)
+ break;
+ }
+ else
+ add = want;
+
+ if (want)
+ want = want->next;
+ }
+ }
+ }
+
+ if (have || want)
+ peer->update_routes6 = 1; /* more to do */
+
+ /* anything changed? */
+ if (!(unreach_len || add))
+ return 1;
+
+ if (unreach_len)
+ {
+ /* go back and insert MP unreach_len */
+ unreach_len += sizeof(struct bgp_attr_mp_unreach_nlri_partial);
+ unreach_len = htons(unreach_len);
+ memcpy(unreach_len_pos, &unreach_len, sizeof(unreach_len));
+ }
+ else
+ {
+ /* we can remove this attribute, then */
+ data -= BGP_PATH_ATTR_MP_UNREACH_NLRI_PARTIAL_SIZE;
+ attr_len -= BGP_PATH_ATTR_MP_UNREACH_NLRI_PARTIAL_SIZE;
+ }
+
+ if (add)
+ {
+ if (!(e = malloc(sizeof(*e))))
+ {
+ LOG(0, 0, 0, "Can't allocate route for %s/%d (%s)\n",
+ inet_ntop(AF_INET6, &add->dest.prefix, ipv6addr, INET6_ADDRSTRLEN),
+ add->dest.len, strerror(errno));
+
+ return 0;
+ }
+
+ memcpy(e, add, sizeof(*e));
+ e->next = 0;
+ peer->routes6 = bgp_insert_route6(peer->routes6, e);
+
+ /* copy MP reachable NLRI heading */
+ memcpy(data, peer->mp_reach_nlri_partial,
+ BGP_PATH_ATTR_MP_REACH_NLRI_PARTIAL_SIZE);
+ /* with proper len */
+ reach_len = BGP_IP_PREFIX_SIZE(add->dest);
+ data[2] = sizeof(struct bgp_attr_mp_reach_nlri_partial) + reach_len;
+ data += BGP_PATH_ATTR_MP_REACH_NLRI_PARTIAL_SIZE;
+ attr_len += BGP_PATH_ATTR_MP_REACH_NLRI_PARTIAL_SIZE;
+
+ memcpy(data, &add->dest, reach_len);
+ data += reach_len;
+ attr_len += reach_len;
+
+ LOG(5, 0, 0, "Advertising route %s/%d to BGP peer %s\n",
+ inet_ntop(AF_INET6, &add->dest.prefix, ipv6addr, INET6_ADDRSTRLEN),
+ add->dest.len, peer->name);
+ }
+
+ /* update len with attributes we added */
+ len += attr_len;
+
+ /* go back and insert attr_len */
+ attr_len = htons(attr_len);
+ memcpy((char *)&peer->outbuf->packet.data + 2, &attr_len, sizeof(attr_len));
+
+ peer->outbuf->packet.header.len = htons(len);
+ peer->outbuf->done = 0;
+
+ return bgp_write(peer);
projects / l2tpns.git / blobdiff