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Move NEXT_HOP attribute so that we can exclude it.
[l2tpns.git] / bgp.c
diff --git a/bgp.c b/bgp.c
index d7701be..10f06a3 100644 (file)
--- a/bgp.c
+++ b/bgp.c
@@ -45,6 +45,8 @@ static int bgp_send_keepalive(struct bgp_peer *peer);
 static int bgp_send_update(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;
@@ -191,15 +193,6 @@ int bgp_start(struct bgp_peer *peer, char *name, int as, int keepalive,
 
     ADD_ATTRIBUTE();
 
-    /* NEXT_HOP */
-    a.flags = BGP_PATH_ATTR_FLAG_TRANS;
-    a.code = BGP_PATH_ATTR_CODE_NEXT_HOP;
-    ip = my_address; /* we're it */
-    a.data.s.len = sizeof(ip);
-    memcpy(a.data.s.value, &ip, sizeof(ip));
-
-    ADD_ATTRIBUTE();
-
     /* MULTI_EXIT_DISC */
     a.flags = BGP_PATH_ATTR_FLAG_OPTIONAL;
     a.code = BGP_PATH_ATTR_CODE_MULTI_EXIT_DISC;
@@ -229,6 +222,18 @@ int bgp_start(struct bgp_peer *peer, char *name, int as, int keepalive,
 
     ADD_ATTRIBUTE();
 
+    /* remember the len before adding NEXT_HOP */
+    peer->path_attr_len_without_nexthop = peer->path_attr_len;
+
+    /* NEXT_HOP */
+    a.flags = BGP_PATH_ATTR_FLAG_TRANS;
+    a.code = BGP_PATH_ATTR_CODE_NEXT_HOP;
+    ip = my_address; /* we're it */
+    a.data.s.len = sizeof(ip);
+    memcpy(a.data.s.value, &ip, sizeof(ip));
+
+    ADD_ATTRIBUTE();
+
     if (!(peer->path_attrs = malloc(peer->path_attr_len)))
     {
        LOG(0, 0, 0, "Can't allocate path_attrs for %s (%s)\n",
@@ -760,6 +765,8 @@ 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);
 }
 
@@ -783,6 +790,8 @@ 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);
 }
 
@@ -907,6 +916,7 @@ static int bgp_handle_input(struct bgp_peer *peer)
            uint8_t capabilities_len;
            char *capabilities = NULL;
            struct bgp_capability *capability;
+           struct bgp_mp_cap_param *mp_cap;
 
            for (i = 0; i < sizeof(p->header.marker); i++)
            {
@@ -979,7 +989,8 @@ static int bgp_handle_input(struct bgp_peer *peer)
 
                /* sensible check */
                if (data.opt_len - param_offset < 2
-                       || param->len > data.opt_len - param_offset - 2) {
+                       || param->len > data.opt_len - param_offset - 2)
+               {
                    LOG(1, 0, 0, "Malformed Optional Parameter list from BGP peer %s\n",
                        peer->name);
 
@@ -988,7 +999,8 @@ static int bgp_handle_input(struct bgp_peer *peer)
                }
 
                /* we know only one parameter type */
-               if (param->type != BGP_CAPABILITY_PARAM_TYPE) {
+               if (param->type != BGP_PARAM_TYPE_CAPABILITY)
+               {
                    LOG(1, 0, 0, "Unsupported Optional Parameter type %d from BGP peer %s\n",
                        param->type, peer->name);
 
@@ -1011,7 +1023,8 @@ static int bgp_handle_input(struct bgp_peer *peer)
 
                    /* sensible check */
                    if (capabilities_len - capability_offset < 2
-                           || capability->len > capabilities_len - capability_offset - 2) {
+                           || capability->len > capabilities_len - capability_offset - 2)
+                   {
                        LOG(1, 0, 0, "Malformed Capabilities list from BGP peer %s\n",
                            peer->name);
 
@@ -1020,14 +1033,32 @@ static int bgp_handle_input(struct bgp_peer *peer)
                    }
 
                    /* we only know one capability code */
-                   if (capability->code != XXX) {
+                   if (capability->code != BGP_CAP_CODE_MP
+                           && capability->len != sizeof(struct bgp_mp_cap_param))
+                   {
                        LOG(4, 0, 0, "Unsupported Capability code %d from BGP peer %s\n",
                            capability->code, peer->name);
 
-                       /* TODO: send _which_ capability is unsupported */
-                       bgp_send_notification(peer, BGP_ERR_OPEN, BGP_ERR_OPN_UNSUP_CAP);
+                       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)
+                   {
+                       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;
                }
            }
 
@@ -1065,6 +1096,17 @@ 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_CAP)
+           {
+               /* the only capability we advertise is this one, so upon receiving
+                  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;
+               break;
+           }
+
            /* FIXME: should handle more notifications */
            LOG(4, 0, 0, "BGP peer %s sent unhandled NOTIFICATION %d\n",
                peer->name, (int) notification->error_code);
@@ -1095,6 +1137,9 @@ 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_capability cap_mp_ipv6;
+    struct bgp_opt_param param_cap_mp_ipv6;
     uint16_t len = sizeof(peer->outbuf->packet.header);
 
     memset(peer->outbuf->packet.header.marker, 0xff,
@@ -1106,7 +1151,18 @@ static int bgp_send_open(struct bgp_peer *peer)
     data.as = htons(our_as);
     data.hold_time = htons(peer->hold);
     data.identifier = my_address;
-    data.opt_len = 0;
+
+    /* 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);
+
+    data.opt_len = 2 + param_cap_mp_ipv6.len;
+    memcpy(&data.opt_params, &param_cap_mp_ipv6, data.opt_len);
 
     memcpy(peer->outbuf->packet.data, &data, BGP_DATA_OPEN_SIZE);
     len += BGP_DATA_OPEN_SIZE;
@@ -1279,6 +1335,12 @@ static int bgp_send_update(struct bgp_peer *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;
@@ -1289,6 +1351,9 @@ static int bgp_send_notification(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));
 
for cloning use: "git clone git://git.sameswireless.fr/l2tpns.git" ; For add to your sources.list: "deb http://package.sameswifi.fr/ jessie main"