X-Git-Url: http://git.sameswireless.fr/l2tpns.git/blobdiff_plain/f4fb6922fee52973e2f568f18411594c88b40aa2..ae7d3c9fca4afa0dcc83095c4405ce3461276075:/bgp.c

diff --git a/bgp.c b/bgp.c
index 1e1713d..901ea55 100644
--- 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;
@@ -103,7 +101,7 @@ int bgp_setup(int as)
 
 /* start connection with a peer */
 int bgp_start(struct bgp_peer *peer, char *name, int as, int keepalive,
-    int hold, int enable)
+    int hold, struct in_addr update_source, int enable)
 {
     struct hostent *h;
     int ibgp;
@@ -132,6 +130,7 @@ int bgp_start(struct bgp_peer *peer, char *name, int as, int keepalive,
     }
 
     memcpy(&peer->addr, h->h_addr, sizeof(peer->addr));
+    peer->source_addr = update_source.s_addr;
     peer->as = as > 0 ? as : our_as;
     ibgp = peer->as == our_as;
 
@@ -234,7 +233,14 @@ int bgp_start(struct bgp_peer *peer, char *name, int as, int keepalive,
     /* NEXT_HOP */
     a.flags = BGP_PATH_ATTR_FLAG_TRANS;
     a.code = BGP_PATH_ATTR_CODE_NEXT_HOP;
-    ip = my_address; /* we're it */
+    if (config->nexthop_address)
+    {
+	ip = config->nexthop_address;
+    }
+    else
+    {
+	ip = my_address; /* we're it */
+    }
     a.data.s.len = sizeof(ip);
     memcpy(a.data.s.value, &ip, sizeof(ip));
 
@@ -250,6 +256,53 @@ 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 +562,8 @@ 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 +663,8 @@ 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",
@@ -858,6 +913,7 @@ static int bgp_connect(struct bgp_peer *peer)
 {
     static int bgp_port = 0;
     struct sockaddr_in addr;
+    struct sockaddr_in source_addr;
     struct epoll_event ev;
 
     if (!bgp_port)
@@ -889,6 +945,19 @@ static int bgp_connect(struct bgp_peer *peer)
     /* set to non-blocking */
     fcntl(peer->sock, F_SETFL, fcntl(peer->sock, F_GETFL, 0) | O_NONBLOCK);
 
+    /* set source address */
+    memset(&source_addr, 0, sizeof(source_addr));
+    source_addr.sin_family = AF_INET;
+    source_addr.sin_addr.s_addr = peer->source_addr; /* defaults to INADDR_ANY */
+    if (bind(peer->sock, (struct sockaddr *) &source_addr, sizeof(source_addr)) < 0)
+    {
+	LOG(1, 0, 0, "Can't set source address to %s: %s\n",
+	    inet_ntoa(source_addr.sin_addr), strerror(errno));
+
+	bgp_set_retry(peer);
+	return 0;
+    }
+
     /* try connect */
     memset(&addr, 0, sizeof(addr));
     addr.sin_family = AF_INET;
@@ -922,8 +991,6 @@ 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 +1014,6 @@ 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 +1207,7 @@ 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 +1232,8 @@ 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 +1258,34 @@ 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);
 	}
@@ -1249,7 +1316,16 @@ static int bgp_handle_input(struct bgp_peer *peer)
 	    if (notification->error_code == BGP_ERR_CEASE)
 	    {
 		LOG(4, 0, 0, "BGP peer %s sent CEASE\n", peer->name);
-		bgp_restart(peer);
+		bgp_set_retry(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_set_retry(peer);
 		return 0;
 	    }
 
@@ -1260,7 +1336,7 @@ 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 +1370,7 @@ 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);
@@ -1307,22 +1383,35 @@ static int bgp_send_open(struct bgp_peer *peer)
     data.version = BGP_VERSION;
     data.as = htons(our_as);
     data.hold_time = htons(peer->hold);
-    data.identifier = my_address;
+    /* use the source IP we use as identifier, if available */
+    if (peer->source_addr != INADDR_ANY)
+	data.identifier = peer->source_addr;
+    else
+	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 +1581,179 @@ 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 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);
 }
 
 /* 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 +1764,6 @@ 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));