Don't send notification when receiving an unsupported capability.
[l2tpns.git] / bgp.c
diff --git a/bgp.c b/bgp.c
index 1e1713d..420a925 100644 (file)
--- a/bgp.c
+++ b/bgp.c
@@ -49,8 +49,6 @@ static int bgp_send_update(struct bgp_peer *peer);
 static int bgp_send_update6(struct bgp_peer *peer);
 static int bgp_send_notification(struct bgp_peer *peer, uint8_t code,
     uint8_t subcode);
-static int bgp_send_notification_full(struct bgp_peer *peer, uint8_t code,
-    uint8_t subcode, char *notification_data, uint16_t data_len);
 
 static uint16_t our_as;
 static struct bgp_route_list *bgp_routes = 0;
@@ -250,6 +248,53 @@ int bgp_start(struct bgp_peer *peer, char *name, int as, int keepalive,
 
     memcpy(peer->path_attrs, path_attrs, peer->path_attr_len);
 
+    /* multiprotocol attributes initialization */
+    if (config->ipv6_prefix.s6_addr[0])
+    {
+       struct bgp_attr_mp_reach_nlri_partial mp_reach_nlri_partial;
+       struct bgp_attr_mp_unreach_nlri_partial mp_unreach_nlri_partial;
+
+       a.flags = BGP_PATH_ATTR_FLAG_OPTIONAL;
+       a.code = BGP_PATH_ATTR_CODE_MP_REACH_NLRI;
+       a.data.s.len = 0; /* will be set on UPDATE */
+
+       mp_reach_nlri_partial.afi = htons(BGP_MP_AFI_IPv6);
+       mp_reach_nlri_partial.safi = BGP_MP_SAFI_UNICAST;
+       mp_reach_nlri_partial.reserved = 0;
+       mp_reach_nlri_partial.next_hop_len = 16;
+
+       /* use the defined nexthop6, or our address in ipv6_prefix */
+       if (config->nexthop6_address.s6_addr[0])
+           memcpy(&mp_reach_nlri_partial.next_hop,
+                   &config->nexthop6_address.s6_addr, 16);
+       else
+       {
+           /* our address is ipv6prefix::1 */
+           memcpy(&mp_reach_nlri_partial.next_hop,
+                   &config->ipv6_prefix.s6_addr, 16);
+           mp_reach_nlri_partial.next_hop[15] = 1;
+       }
+
+       memcpy(&a.data.s.value, &mp_reach_nlri_partial,
+               sizeof(struct bgp_attr_mp_reach_nlri_partial));
+       memcpy(&peer->mp_reach_nlri_partial, &a,
+               BGP_PATH_ATTR_MP_REACH_NLRI_PARTIAL_SIZE);
+
+       a.flags = BGP_PATH_ATTR_FLAG_OPTIONAL | BGP_PATH_ATTR_FLAG_EXTLEN;
+       a.code = BGP_PATH_ATTR_CODE_MP_UNREACH_NLRI;
+       a.data.e.len = 0; /* will be set on UPDATE */
+
+       mp_unreach_nlri_partial.afi = htons(BGP_MP_AFI_IPv6);
+       mp_unreach_nlri_partial.safi = BGP_MP_SAFI_UNICAST;
+
+       memcpy(&a.data.e.value, &mp_unreach_nlri_partial,
+               sizeof(struct bgp_attr_mp_unreach_nlri_partial));
+       memcpy(&peer->mp_unreach_nlri_partial, &a,
+               BGP_PATH_ATTR_MP_UNREACH_NLRI_PARTIAL_SIZE);
+    }
+
+    peer->mp_handling = HandlingUnknown;
+
     LOG(4, 0, 0, "Initiating BGP connection to %s (routing %s)\n",
        name, enable ? "enabled" : "suspended");
 
@@ -509,7 +554,8 @@ int bgp_add_route6(struct in6_addr ip, int prefixlen)
 
     /* flag established peers for update */
     for (i = 0; i < BGP_NUM_PEERS; i++)
-       if (bgp_peers[i].state == Established)
+       if (bgp_peers[i].state == Established
+               && bgp_peers[i].mp_handling == HandleIPv6Routes)
            bgp_peers[i].update_routes6 = 1;
 
     LOG(4, 0, 0, "Registered BGP route %s/%d\n",
@@ -609,7 +655,8 @@ int bgp_del_route6(struct in6_addr ip, int prefixlen)
 
     /* flag established peers for update */
     for (i = 0; i < BGP_NUM_PEERS; i++)
-       if (bgp_peers[i].state == Established)
+       if (bgp_peers[i].state == Established
+               && bgp_peers[i].mp_handling == HandleIPv6Routes)
            bgp_peers[i].update_routes6 = 1;
 
     LOG(4, 0, 0, "Removed BGP route %s/%d\n",
@@ -922,8 +969,6 @@ static int bgp_connect(struct bgp_peer *peer)
 
     LOG(4, 0, 0, "BGP peer %s: state Active\n", inet_ntoa(addr.sin_addr));
 
-    peer->handle_ipv6_routes = 0;
-
     return bgp_send_open(peer);
 }
 
@@ -947,8 +992,6 @@ static int bgp_handle_connect(struct bgp_peer *peer)
 
     LOG(4, 0, 0, "BGP peer %s: state Active\n", peer->name);
 
-    peer->handle_ipv6_routes = 0;
-
     return bgp_send_open(peer);
 }
 
@@ -1142,7 +1185,7 @@ static int bgp_handle_input(struct bgp_peer *peer)
                    param_offset < data.opt_len;
                    param_offset += 2 + param->len)
            {
-               param = (struct bgp_opt_param *)(&data.opt_params + param_offset);
+               param = (struct bgp_opt_param *)((char *)&data.opt_params + param_offset);
 
                /* sensible check */
                if (data.opt_len - param_offset < 2
@@ -1167,11 +1210,8 @@ static int bgp_handle_input(struct bgp_peer *peer)
 
                capabilities_len = param->len;
                capabilities = (char *)&param->value;
-           }
 
-           /* look for BGP multiprotocol capability */
-           if (capabilities)
-           {
+               /* look for BGP multiprotocol capability */
                for (capability_offset = 0;
                        capability_offset < capabilities_len;
                        capability_offset += 2 + capability->len)
@@ -1196,29 +1236,34 @@ static int bgp_handle_input(struct bgp_peer *peer)
                        LOG(4, 0, 0, "Unsupported Capability code %d from BGP peer %s\n",
                            capability->code, peer->name);
 
-                       bgp_send_notification_full(peer, BGP_ERR_OPEN, BGP_ERR_OPN_UNSUP_CAP,
-                               (char *)capability, 2 + capability->len);
                        /* we don't terminate, still; we just jump to the next one */
                        continue;
                    }
 
                    mp_cap = (struct bgp_mp_cap_param *)&capability->value;
                    /* the only <AFI, SAFI> tuple we support */
-                   if (ntohs(mp_cap->afi) != AF_INET6 && mp_cap->safi != BGP_MP_SAFI_UNICAST)
+                   if (ntohs(mp_cap->afi) != BGP_MP_AFI_IPv6 && mp_cap->safi != BGP_MP_SAFI_UNICAST)
                    {
                        LOG(4, 0, 0, "Unsupported multiprotocol AFI %d and SAFI %d from BGP peer %s\n",
                            mp_cap->afi, mp_cap->safi, peer->name);
 
-                       bgp_send_notification_full(peer, BGP_ERR_OPEN, BGP_ERR_OPN_UNSUP_CAP,
-                               (char *)capability, 2 + capability->len);
                        /* we don't terminate, still; we just jump to the next one */
                        continue;
                    }
 
-                   peer->handle_ipv6_routes = 1;
+                   /* yes it can! */
+                   peer->mp_handling = HandleIPv6Routes;
                }
            }
 
+           if (peer->mp_handling != HandleIPv6Routes)
+           {
+               peer->mp_handling = DoesntHandleIPv6Routes;
+               if (config->ipv6_prefix.s6_addr[0])
+                   LOG(1, 0, 0, "Warning: BGP peer %s doesn't handle IPv6 prefixes updates\n",
+                           peer->name);
+           }
+
            /* next transition requires an exchange of keepalives */
            bgp_send_keepalive(peer);
        }
@@ -1253,6 +1298,15 @@ static int bgp_handle_input(struct bgp_peer *peer)
                return 0;
            }
 
+           if (notification->error_code == BGP_ERR_OPEN
+                   && notification->error_subcode == BGP_ERR_OPN_UNSUP_PARAM)
+           {
+               LOG(4, 0, 0, "BGP peer %s doesn't support BGP Capabilities\n", peer->name);
+               peer->mp_handling = DoesntHandleIPv6Routes;
+               bgp_restart(peer);
+               return 0;
+           }
+
            if (notification->error_code == BGP_ERR_OPEN
                    && notification->error_subcode == BGP_ERR_OPN_UNSUP_CAP)
            {
@@ -1260,7 +1314,7 @@ static int bgp_handle_input(struct bgp_peer *peer)
                   an "unsupported capability" message, we disable IPv6 routes for
                   this peer */
                LOG(4, 0, 0, "BGP peer %s doesn't support IPv6 routes advertisement\n", peer->name);
-               peer->handle_ipv6_routes = 0;
+               peer->mp_handling = DoesntHandleIPv6Routes;
                break;
            }
 
@@ -1294,7 +1348,7 @@ static int bgp_handle_input(struct bgp_peer *peer)
 static int bgp_send_open(struct bgp_peer *peer)
 {
     struct bgp_data_open data;
-    struct bgp_mp_cap_param mp_ipv6 = { htons(AF_INET6), 0, BGP_MP_SAFI_UNICAST };
+    struct bgp_mp_cap_param mp_ipv6 = { htons(BGP_MP_AFI_IPv6), 0, BGP_MP_SAFI_UNICAST };
     struct bgp_capability cap_mp_ipv6;
     struct bgp_opt_param param_cap_mp_ipv6;
     uint16_t len = sizeof(peer->outbuf->packet.header);
@@ -1309,20 +1363,29 @@ static int bgp_send_open(struct bgp_peer *peer)
     data.hold_time = htons(peer->hold);
     data.identifier = my_address;
 
-    /* construct the param and capability */
-    cap_mp_ipv6.code = BGP_CAP_CODE_MP;
-    cap_mp_ipv6.len = sizeof(mp_ipv6);
-    memcpy(&cap_mp_ipv6.value, &mp_ipv6, cap_mp_ipv6.len);
+    /* if we know peer doesn't support MP (mp_handling == DoesntHandleIPv6Routes)
+       then don't add this parameter */
+    if (config->ipv6_prefix.s6_addr[0]
+           && (peer->mp_handling == HandlingUnknown
+               || peer->mp_handling == HandleIPv6Routes))
+    {
+       /* construct the param and capability */
+       cap_mp_ipv6.code = BGP_CAP_CODE_MP;
+       cap_mp_ipv6.len = sizeof(mp_ipv6);
+       memcpy(&cap_mp_ipv6.value, &mp_ipv6, cap_mp_ipv6.len);
 
-    param_cap_mp_ipv6.type = BGP_PARAM_TYPE_CAPABILITY;
-    param_cap_mp_ipv6.len = 2 + sizeof(mp_ipv6);
-    memcpy(&param_cap_mp_ipv6.value, &cap_mp_ipv6, param_cap_mp_ipv6.len);
+       param_cap_mp_ipv6.type = BGP_PARAM_TYPE_CAPABILITY;
+       param_cap_mp_ipv6.len = 2 + sizeof(mp_ipv6);
+       memcpy(&param_cap_mp_ipv6.value, &cap_mp_ipv6, param_cap_mp_ipv6.len);
 
-    data.opt_len = 2 + param_cap_mp_ipv6.len;
-    memcpy(&data.opt_params, &param_cap_mp_ipv6, data.opt_len);
+       data.opt_len = 2 + param_cap_mp_ipv6.len;
+       memcpy(&data.opt_params, &param_cap_mp_ipv6, data.opt_len);
+    }
+    else
+       data.opt_len = 0;
 
-    memcpy(peer->outbuf->packet.data, &data, BGP_DATA_OPEN_SIZE);
-    len += BGP_DATA_OPEN_SIZE;
+    memcpy(peer->outbuf->packet.data, &data, BGP_DATA_OPEN_SIZE + data.opt_len);
+    len += BGP_DATA_OPEN_SIZE + data.opt_len;
 
     peer->outbuf->packet.header.len = htons(len);
     peer->outbuf->done = 0;
@@ -1492,17 +1555,167 @@ static int bgp_send_update(struct bgp_peer *peer)
 /* send/buffer UPDATE message for IPv6 routes */
 static int bgp_send_update6(struct bgp_peer *peer)
 {
+    uint16_t unf_len = 0;
+    uint16_t attr_len;
+    char *unreach_len;
+    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 unf_len */
+    memcpy(data, &unf_len, sizeof(unf_len));
+    /* skip over attr_len too; will be filled when known */
+    data += sizeof(unf_len) + sizeof(attr_len);
+    len += sizeof(unf_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;
+    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 = data + 2;
+    data += BGP_PATH_ATTR_MP_UNREACH_NLRI_PARTIAL_SIZE;
+    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;
+           unf_len += s;
+           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 (!(unf_len || add))
+       return 1;
+
+    /* go back and insert MP unf_len */
+    unf_len += sizeof(struct bgp_attr_mp_unreach_nlri_partial);
+    unf_len = htons(unf_len);
+    memcpy(&unreach_len, &unf_len, sizeof(unf_len));
+
+    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] = reach_len;
+       data += BGP_PATH_ATTR_MP_UNREACH_NLRI_PARTIAL_SIZE;
+       len += BGP_PATH_ATTR_MP_UNREACH_NLRI_PARTIAL_SIZE;
+
+       memcpy(data, &add->dest, reach_len);
+       data += reach_len;
+       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);
+    }
+
+    /* go back and insert attr_len */
+    attr_len = htons(len - 4);
+    memcpy(&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);
 }
 
 /* send/buffer NOTIFICATION message */
 static int bgp_send_notification(struct bgp_peer *peer, uint8_t code,
     uint8_t subcode)
-{
-    return bgp_send_notification_full(peer, code, subcode, NULL, 0);
-}
-
-static int bgp_send_notification_full(struct bgp_peer *peer, uint8_t code,
-    uint8_t subcode, char *notification_data, uint16_t data_len)
 {
     struct bgp_data_notification data;
     uint16_t len = 0;
@@ -1513,9 +1726,6 @@ static int bgp_send_notification_full(struct bgp_peer *peer, uint8_t code,
     data.error_subcode = subcode;
     len += sizeof(data.error_code);
 
-    memcpy(data.data, notification_data, data_len);
-    len += data_len;
-
     memset(peer->outbuf->packet.header.marker, 0xff,
        sizeof(peer->outbuf->packet.header.marker));