1 /* BGP carrying label information
2 * Copyright (C) 2013 Cumulus Networks, Inc.
4 * This file is part of GNU Zebra.
6 * GNU Zebra is free software; you can redistribute it and/or modify it
7 * under the terms of the GNU General Public License as published by the
8 * Free Software Foundation; either version 2, or (at your option) any
11 * GNU Zebra is distributed in the hope that it will be useful, but
12 * WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 * General Public License for more details.
16 * You should have received a copy of the GNU General Public License along
17 * with this program; see the file COPYING; if not, write to the Free Software
18 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
34 #include "bgpd/bgpd.h"
35 #include "bgpd/bgp_table.h"
36 #include "bgpd/bgp_route.h"
37 #include "bgpd/bgp_attr.h"
38 #include "bgpd/bgp_label.h"
39 #include "bgpd/bgp_packet.h"
40 #include "bgpd/bgp_debug.h"
41 #include "bgpd/bgp_errors.h"
43 extern struct zclient
*zclient
;
45 int bgp_parse_fec_update(void)
48 struct bgp_dest
*dest
;
50 struct bgp_table
*table
;
58 memset(&p
, 0, sizeof(struct prefix
));
59 p
.family
= stream_getw(s
);
60 p
.prefixlen
= stream_getc(s
);
61 stream_get(p
.u
.val
, s
, PSIZE(p
.prefixlen
));
62 label
= stream_getl(s
);
64 /* hack for the bgp instance & SAFI = have to send/receive it */
65 afi
= family2afi(p
.family
);
67 bgp
= bgp_get_default();
69 zlog_debug("no default bgp instance");
73 table
= bgp
->rib
[afi
][safi
];
75 zlog_debug("no %u unicast table", p
.family
);
78 dest
= bgp_node_lookup(table
, &p
);
80 zlog_debug("no node for the prefix");
84 /* treat it as implicit withdraw - the label is invalid */
85 if (label
== MPLS_INVALID_LABEL
)
86 bgp_unset_valid_label(&dest
->local_label
);
88 label_ntop(label
, 1, &dest
->local_label
);
89 bgp_set_valid_label(&dest
->local_label
);
91 SET_FLAG(dest
->flags
, BGP_NODE_LABEL_CHANGED
);
92 bgp_process(bgp
, dest
, afi
, safi
);
93 bgp_dest_unlock_node(dest
);
97 mpls_label_t
bgp_adv_label(struct bgp_dest
*dest
, struct bgp_path_info
*pi
,
98 struct peer
*to
, afi_t afi
, safi_t safi
)
101 mpls_label_t remote_label
;
104 if (!dest
|| !pi
|| !to
)
105 return MPLS_INVALID_LABEL
;
107 remote_label
= pi
->extra
? pi
->extra
->label
[0] : MPLS_INVALID_LABEL
;
110 ((from
->sort
== BGP_PEER_IBGP
) && (to
->sort
== BGP_PEER_IBGP
));
113 && !CHECK_FLAG(to
->af_flags
[afi
][safi
],
114 PEER_FLAG_FORCE_NEXTHOP_SELF
))
117 if (CHECK_FLAG(to
->af_flags
[afi
][safi
], PEER_FLAG_NEXTHOP_UNCHANGED
))
120 return dest
->local_label
;
123 static void bgp_send_fec_register_label_msg(struct bgp_dest
*dest
, bool reg
,
124 uint32_t label_index
)
128 const struct prefix
*p
;
130 size_t flags_pos
= 0;
131 mpls_label_t
*local_label
= &(dest
->local_label
);
132 bool have_label_to_reg
=
133 bgp_is_valid_label(local_label
)
134 && label_pton(local_label
) != MPLS_LABEL_IMPLICIT_NULL
;
136 p
= bgp_dest_get_prefix(dest
);
139 if (!zclient
|| zclient
->sock
< 0)
142 if (BGP_DEBUG(labelpool
, LABELPOOL
))
143 zlog_debug("%s: FEC %sregister %pRN label_index=%u label=%u",
144 __func__
, reg
? "" : "un", bgp_dest_to_rnode(dest
),
145 label_index
, label_pton(local_label
));
146 /* If the route node has a local_label assigned or the
147 * path node has an MPLS SR label index allowing zebra to
148 * derive the label, proceed with registration. */
151 command
= (reg
) ? ZEBRA_FEC_REGISTER
: ZEBRA_FEC_UNREGISTER
;
152 zclient_create_header(s
, command
, VRF_DEFAULT
);
153 flags_pos
= stream_get_endp(s
); /* save position of 'flags' */
154 stream_putw(s
, flags
); /* initial flags */
155 stream_putw(s
, PREFIX_FAMILY(p
));
156 stream_put_prefix(s
, p
);
158 /* label index takes precedence over auto-assigned label. */
159 if (label_index
!= 0) {
160 flags
|= ZEBRA_FEC_REGISTER_LABEL_INDEX
;
161 stream_putl(s
, label_index
);
162 } else if (have_label_to_reg
) {
163 flags
|= ZEBRA_FEC_REGISTER_LABEL
;
164 stream_putl(s
, label_pton(local_label
));
166 SET_FLAG(dest
->flags
, BGP_NODE_REGISTERED_FOR_LABEL
);
168 UNSET_FLAG(dest
->flags
, BGP_NODE_REGISTERED_FOR_LABEL
);
170 /* Set length and flags */
171 stream_putw_at(s
, 0, stream_get_endp(s
));
174 * We only need to write new flags if this is a register
177 stream_putw_at(s
, flags_pos
, flags
);
179 zclient_send_message(zclient
);
183 * This is passed as the callback function to bgp_labelpool.c:bgp_lp_get()
184 * by bgp_reg_dereg_for_label() when a label needs to be obtained from
186 * Note that it will reject the allocated label if a label index is found,
187 * because the label index supposes predictable labels
189 int bgp_reg_for_label_callback(mpls_label_t new_label
, void *labelid
,
192 struct bgp_dest
*dest
;
197 * if the route had been removed or the request has gone then reject
198 * the allocated label. The requesting code will have done what is
199 * required to allocate the correct label
201 if (!CHECK_FLAG(dest
->flags
, BGP_NODE_LABEL_REQUESTED
)) {
202 bgp_dest_unlock_node(dest
);
206 bgp_dest_unlock_node(dest
);
208 if (BGP_DEBUG(labelpool
, LABELPOOL
))
209 zlog_debug("%s: FEC %pRN label=%u, allocated=%d", __func__
,
210 bgp_dest_to_rnode(dest
), new_label
, allocated
);
214 * previously-allocated label is now invalid, set to implicit
215 * null until new label arrives
217 if (CHECK_FLAG(dest
->flags
, BGP_NODE_REGISTERED_FOR_LABEL
)) {
218 UNSET_FLAG(dest
->flags
, BGP_NODE_LABEL_REQUESTED
);
219 label_ntop(MPLS_LABEL_IMPLICIT_NULL
, 1,
221 bgp_set_valid_label(&dest
->local_label
);
225 label_ntop(new_label
, 1, &dest
->local_label
);
226 bgp_set_valid_label(&dest
->local_label
);
229 * Get back to registering the FEC
231 bgp_send_fec_register_label_msg(dest
, true, 0);
236 void bgp_reg_dereg_for_label(struct bgp_dest
*dest
, struct bgp_path_info
*pi
,
239 bool with_label_index
= false;
240 const struct prefix
*p
;
241 bool have_label_to_reg
=
242 bgp_is_valid_label(&dest
->local_label
)
243 && label_pton(&dest
->local_label
) != MPLS_LABEL_IMPLICIT_NULL
;
245 p
= bgp_dest_get_prefix(dest
);
247 if (BGP_DEBUG(labelpool
, LABELPOOL
))
248 zlog_debug("%s: %pFX: %s ", __func__
, p
,
249 (reg
? "reg" : "dereg"));
254 * Determine if we will let zebra should derive label from
255 * label index instead of bgpd requesting from label pool
257 if (CHECK_FLAG(pi
->attr
->flag
,
258 ATTR_FLAG_BIT(BGP_ATTR_PREFIX_SID
))
259 && pi
->attr
->label_index
!= BGP_INVALID_LABEL_INDEX
) {
260 with_label_index
= true;
261 UNSET_FLAG(dest
->flags
, BGP_NODE_LABEL_REQUESTED
);
264 * If no label has been registered -- assume any label
265 * from label pool will do. This means that label index
266 * always takes precedence over auto-assigned labels.
268 if (!have_label_to_reg
) {
269 SET_FLAG(dest
->flags
, BGP_NODE_LABEL_REQUESTED
);
270 if (BGP_DEBUG(labelpool
, LABELPOOL
))
272 "%s: Requesting label from LP for %pFX",
274 /* bgp_reg_for_label_callback() will deal with
275 * fec registration when it gets a label from
276 * the pool. This means we'll never register
277 * FECs withoutvalid labels.
279 bgp_lp_get(LP_TYPE_BGP_LU
, dest
,
280 bgp_reg_for_label_callback
);
285 UNSET_FLAG(dest
->flags
, BGP_NODE_LABEL_REQUESTED
);
286 bgp_lp_release(LP_TYPE_BGP_LU
, dest
,
287 label_pton(&dest
->local_label
));
290 bgp_send_fec_register_label_msg(
291 dest
, reg
, with_label_index
? pi
->attr
->label_index
: 0);
294 static int bgp_nlri_get_labels(struct peer
*peer
, uint8_t *pnt
, uint8_t plen
,
298 uint8_t *lim
= pnt
+ plen
;
300 uint8_t label_depth
= 0;
302 for (; data
< lim
; data
+= BGP_LABEL_BYTES
) {
303 memcpy(label
, data
, BGP_LABEL_BYTES
);
304 llen
+= BGP_LABEL_BYTES
;
306 bgp_set_valid_label(label
);
309 if (bgp_is_withdraw_label(label
) || label_bos(label
))
313 /* If we RX multiple labels we will end up keeping only the last
314 * one. We do not yet support a label stack greater than 1. */
316 zlog_info("%pBP rcvd UPDATE with label stack %d deep", peer
,
319 if (!(bgp_is_withdraw_label(label
) || label_bos(label
)))
321 EC_BGP_INVALID_LABEL_STACK
,
322 "%pBP rcvd UPDATE with invalid label stack - no bottom of stack",
328 int bgp_nlri_parse_label(struct peer
*peer
, struct attr
*attr
,
329 struct bgp_nlri
*packet
)
338 bool addpath_capable
;
340 mpls_label_t label
= MPLS_INVALID_LABEL
;
344 lim
= pnt
+ packet
->length
;
349 addpath_capable
= bgp_addpath_encode_rx(peer
, afi
, safi
);
351 for (; pnt
< lim
; pnt
+= psize
) {
352 /* Clear prefix structure. */
353 memset(&p
, 0, sizeof(struct prefix
));
355 if (addpath_capable
) {
357 /* When packet overflow occurs return immediately. */
358 if (pnt
+ BGP_ADDPATH_ID_LEN
> lim
)
359 return BGP_NLRI_PARSE_ERROR_PACKET_OVERFLOW
;
361 memcpy(&addpath_id
, pnt
, BGP_ADDPATH_ID_LEN
);
362 addpath_id
= ntohl(addpath_id
);
363 pnt
+= BGP_ADDPATH_ID_LEN
;
366 /* Fetch prefix length. */
368 p
.family
= afi2family(packet
->afi
);
369 psize
= PSIZE(prefixlen
);
371 /* sanity check against packet data */
372 if ((pnt
+ psize
) > lim
) {
375 "%s [Error] Update packet error / L-U (prefix length %d exceeds packet size %u)",
376 peer
->host
, prefixlen
, (uint
)(lim
- pnt
));
377 return BGP_NLRI_PARSE_ERROR_PACKET_OVERFLOW
;
380 /* Fill in the labels */
381 llen
= bgp_nlri_get_labels(peer
, pnt
, psize
, &label
);
382 p
.prefixlen
= prefixlen
- BSIZE(llen
);
384 /* There needs to be at least one label */
385 if (prefixlen
< 24) {
386 flog_err(EC_BGP_UPDATE_RCV
,
387 "%s [Error] Update packet error (wrong label length %d)",
388 peer
->host
, prefixlen
);
389 bgp_notify_send(peer
, BGP_NOTIFY_UPDATE_ERR
,
390 BGP_NOTIFY_UPDATE_INVAL_NETWORK
);
391 return BGP_NLRI_PARSE_ERROR_LABEL_LENGTH
;
394 if ((afi
== AFI_IP
&& p
.prefixlen
> IPV4_MAX_BITLEN
)
395 || (afi
== AFI_IP6
&& p
.prefixlen
> IPV6_MAX_BITLEN
))
396 return BGP_NLRI_PARSE_ERROR_PREFIX_LENGTH
;
398 /* Fetch prefix from NLRI packet */
399 memcpy(&p
.u
.prefix
, pnt
+ llen
, psize
- llen
);
402 if (afi
== AFI_IP
&& safi
== SAFI_LABELED_UNICAST
) {
403 if (IN_CLASSD(ntohl(p
.u
.prefix4
.s_addr
))) {
404 /* From RFC4271 Section 6.3:
406 * If a prefix in the NLRI field is semantically
408 * (e.g., an unexpected multicast IP address),
410 * be logged locally, and the prefix SHOULD be
415 "%s: IPv4 labeled-unicast NLRI is multicast address %pI4, ignoring",
416 peer
->host
, &p
.u
.prefix4
);
422 if (afi
== AFI_IP6
&& safi
== SAFI_LABELED_UNICAST
) {
423 if (IN6_IS_ADDR_LINKLOCAL(&p
.u
.prefix6
)) {
426 "%s: IPv6 labeled-unicast NLRI is link-local address %pI6, ignoring",
427 peer
->host
, &p
.u
.prefix6
);
432 if (IN6_IS_ADDR_MULTICAST(&p
.u
.prefix6
)) {
435 "%s: IPv6 unicast NLRI is multicast address %pI6, ignoring",
436 peer
->host
, &p
.u
.prefix6
);
443 bgp_update(peer
, &p
, addpath_id
, attr
, packet
->afi
,
444 safi
, ZEBRA_ROUTE_BGP
, BGP_ROUTE_NORMAL
,
445 NULL
, &label
, 1, 0, NULL
);
447 bgp_withdraw(peer
, &p
, addpath_id
, attr
, packet
->afi
,
448 SAFI_UNICAST
, ZEBRA_ROUTE_BGP
,
449 BGP_ROUTE_NORMAL
, NULL
, &label
, 1, NULL
);
453 /* Packet length consistency check. */
457 "%s [Error] Update packet error / L-U (%td data remaining after parsing)",
458 peer
->host
, lim
- pnt
);
459 return BGP_NLRI_PARSE_ERROR_PACKET_LENGTH
;
462 return BGP_NLRI_PARSE_OK
;