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(p
));
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 dest
->local_label
= mpls_lse_encode(label
, 0, 0, 1);
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
);
135 mpls_label_t label
= MPLS_INVALID_LABEL
;
136 bool have_label_to_reg
;
138 mpls_lse_decode(*local_label
, &label
, &ttl
, &exp
, &bos
);
140 have_label_to_reg
= bgp_is_valid_label(local_label
) &&
141 label
!= MPLS_LABEL_IMPLICIT_NULL
;
143 p
= bgp_dest_get_prefix(dest
);
146 if (!zclient
|| zclient
->sock
< 0)
149 if (BGP_DEBUG(labelpool
, LABELPOOL
))
150 zlog_debug("%s: FEC %sregister %pRN label_index=%u label=%u",
151 __func__
, reg
? "" : "un", bgp_dest_to_rnode(dest
),
153 /* If the route node has a local_label assigned or the
154 * path node has an MPLS SR label index allowing zebra to
155 * derive the label, proceed with registration. */
158 command
= (reg
) ? ZEBRA_FEC_REGISTER
: ZEBRA_FEC_UNREGISTER
;
159 zclient_create_header(s
, command
, VRF_DEFAULT
);
160 flags_pos
= stream_get_endp(s
); /* save position of 'flags' */
161 stream_putw(s
, flags
); /* initial flags */
162 stream_putw(s
, PREFIX_FAMILY(p
));
163 stream_put_prefix(s
, p
);
165 /* label index takes precedence over auto-assigned label. */
166 if (label_index
!= 0) {
167 flags
|= ZEBRA_FEC_REGISTER_LABEL_INDEX
;
168 stream_putl(s
, label_index
);
169 } else if (have_label_to_reg
) {
170 flags
|= ZEBRA_FEC_REGISTER_LABEL
;
171 stream_putl(s
, label
);
173 SET_FLAG(dest
->flags
, BGP_NODE_REGISTERED_FOR_LABEL
);
175 UNSET_FLAG(dest
->flags
, BGP_NODE_REGISTERED_FOR_LABEL
);
177 /* Set length and flags */
178 stream_putw_at(s
, 0, stream_get_endp(s
));
181 * We only need to write new flags if this is a register
184 stream_putw_at(s
, flags_pos
, flags
);
186 zclient_send_message(zclient
);
190 * This is passed as the callback function to bgp_labelpool.c:bgp_lp_get()
191 * by bgp_reg_dereg_for_label() when a label needs to be obtained from
193 * Note that it will reject the allocated label if a label index is found,
194 * because the label index supposes predictable labels
196 int bgp_reg_for_label_callback(mpls_label_t new_label
, void *labelid
,
199 struct bgp_dest
*dest
;
204 * if the route had been removed or the request has gone then reject
205 * the allocated label. The requesting code will have done what is
206 * required to allocate the correct label
208 if (!CHECK_FLAG(dest
->flags
, BGP_NODE_LABEL_REQUESTED
)) {
209 bgp_dest_unlock_node(dest
);
213 bgp_dest_unlock_node(dest
);
215 if (BGP_DEBUG(labelpool
, LABELPOOL
))
216 zlog_debug("%s: FEC %pRN label=%u, allocated=%d", __func__
,
217 bgp_dest_to_rnode(dest
), new_label
, allocated
);
221 * previously-allocated label is now invalid, set to implicit
222 * null until new label arrives
224 if (CHECK_FLAG(dest
->flags
, BGP_NODE_REGISTERED_FOR_LABEL
)) {
225 UNSET_FLAG(dest
->flags
, BGP_NODE_LABEL_REQUESTED
);
226 dest
->local_label
= mpls_lse_encode(
227 MPLS_LABEL_IMPLICIT_NULL
, 0, 0, 1);
228 bgp_set_valid_label(&dest
->local_label
);
232 dest
->local_label
= mpls_lse_encode(new_label
, 0, 0, 1);
233 bgp_set_valid_label(&dest
->local_label
);
236 * Get back to registering the FEC
238 bgp_send_fec_register_label_msg(dest
, true, 0);
243 void bgp_reg_dereg_for_label(struct bgp_dest
*dest
, struct bgp_path_info
*pi
,
246 bool with_label_index
= false;
247 const struct prefix
*p
;
248 bool have_label_to_reg
;
252 mpls_label_t label
= MPLS_INVALID_LABEL
;
254 mpls_lse_decode(dest
->local_label
, &label
, &ttl
, &exp
, &bos
);
256 have_label_to_reg
= bgp_is_valid_label(&dest
->local_label
) &&
257 label
!= MPLS_LABEL_IMPLICIT_NULL
;
259 p
= bgp_dest_get_prefix(dest
);
261 if (BGP_DEBUG(labelpool
, LABELPOOL
))
262 zlog_debug("%s: %pFX: %s ", __func__
, p
,
263 (reg
? "reg" : "dereg"));
268 * Determine if we will let zebra should derive label from
269 * label index instead of bgpd requesting from label pool
271 if (CHECK_FLAG(pi
->attr
->flag
,
272 ATTR_FLAG_BIT(BGP_ATTR_PREFIX_SID
))
273 && pi
->attr
->label_index
!= BGP_INVALID_LABEL_INDEX
) {
274 with_label_index
= true;
275 UNSET_FLAG(dest
->flags
, BGP_NODE_LABEL_REQUESTED
);
278 * If no label has been registered -- assume any label
279 * from label pool will do. This means that label index
280 * always takes precedence over auto-assigned labels.
282 if (!have_label_to_reg
) {
283 SET_FLAG(dest
->flags
, BGP_NODE_LABEL_REQUESTED
);
284 if (BGP_DEBUG(labelpool
, LABELPOOL
))
286 "%s: Requesting label from LP for %pFX",
288 /* bgp_reg_for_label_callback() will deal with
289 * fec registration when it gets a label from
290 * the pool. This means we'll never register
291 * FECs withoutvalid labels.
293 bgp_lp_get(LP_TYPE_BGP_LU
, dest
,
294 bgp_reg_for_label_callback
);
299 UNSET_FLAG(dest
->flags
, BGP_NODE_LABEL_REQUESTED
);
300 bgp_lp_release(LP_TYPE_BGP_LU
, dest
, label
);
303 bgp_send_fec_register_label_msg(
304 dest
, reg
, with_label_index
? pi
->attr
->label_index
: 0);
307 static int bgp_nlri_get_labels(struct peer
*peer
, uint8_t *pnt
, uint8_t plen
,
311 uint8_t *lim
= pnt
+ plen
;
313 uint8_t label_depth
= 0;
315 for (; data
< lim
; data
+= BGP_LABEL_BYTES
) {
316 memcpy(label
, data
, BGP_LABEL_BYTES
);
317 llen
+= BGP_LABEL_BYTES
;
319 bgp_set_valid_label(label
);
322 if (bgp_is_withdraw_label(label
) || label_bos(label
))
326 /* If we RX multiple labels we will end up keeping only the last
327 * one. We do not yet support a label stack greater than 1. */
329 zlog_info("%pBP rcvd UPDATE with label stack %d deep", peer
,
332 if (!(bgp_is_withdraw_label(label
) || label_bos(label
)))
334 EC_BGP_INVALID_LABEL_STACK
,
335 "%pBP rcvd UPDATE with invalid label stack - no bottom of stack",
341 int bgp_nlri_parse_label(struct peer
*peer
, struct attr
*attr
,
342 struct bgp_nlri
*packet
)
351 bool addpath_capable
;
353 mpls_label_t label
= MPLS_INVALID_LABEL
;
357 lim
= pnt
+ packet
->length
;
362 addpath_capable
= bgp_addpath_encode_rx(peer
, afi
, safi
);
364 for (; pnt
< lim
; pnt
+= psize
) {
365 /* Clear prefix structure. */
366 memset(&p
, 0, sizeof(p
));
368 if (addpath_capable
) {
370 /* When packet overflow occurs return immediately. */
371 if (pnt
+ BGP_ADDPATH_ID_LEN
> lim
)
372 return BGP_NLRI_PARSE_ERROR_PACKET_OVERFLOW
;
374 memcpy(&addpath_id
, pnt
, BGP_ADDPATH_ID_LEN
);
375 addpath_id
= ntohl(addpath_id
);
376 pnt
+= BGP_ADDPATH_ID_LEN
;
379 /* Fetch prefix length. */
381 p
.family
= afi2family(packet
->afi
);
382 psize
= PSIZE(prefixlen
);
384 /* sanity check against packet data */
385 if ((pnt
+ psize
) > lim
) {
388 "%s [Error] Update packet error / L-U (prefix length %d exceeds packet size %u)",
389 peer
->host
, prefixlen
, (uint
)(lim
- pnt
));
390 return BGP_NLRI_PARSE_ERROR_PACKET_OVERFLOW
;
393 /* Fill in the labels */
394 llen
= bgp_nlri_get_labels(peer
, pnt
, psize
, &label
);
395 p
.prefixlen
= prefixlen
- BSIZE(llen
);
397 /* There needs to be at least one label */
398 if (prefixlen
< 24) {
399 flog_err(EC_BGP_UPDATE_RCV
,
400 "%s [Error] Update packet error (wrong label length %d)",
401 peer
->host
, prefixlen
);
402 bgp_notify_send(peer
, BGP_NOTIFY_UPDATE_ERR
,
403 BGP_NOTIFY_UPDATE_INVAL_NETWORK
);
404 return BGP_NLRI_PARSE_ERROR_LABEL_LENGTH
;
407 if ((afi
== AFI_IP
&& p
.prefixlen
> IPV4_MAX_BITLEN
)
408 || (afi
== AFI_IP6
&& p
.prefixlen
> IPV6_MAX_BITLEN
))
409 return BGP_NLRI_PARSE_ERROR_PREFIX_LENGTH
;
411 /* Fetch prefix from NLRI packet */
412 memcpy(&p
.u
.prefix
, pnt
+ llen
, psize
- llen
);
415 if (afi
== AFI_IP
&& safi
== SAFI_LABELED_UNICAST
) {
416 if (IN_CLASSD(ntohl(p
.u
.prefix4
.s_addr
))) {
417 /* From RFC4271 Section 6.3:
419 * If a prefix in the NLRI field is semantically
421 * (e.g., an unexpected multicast IP address),
423 * be logged locally, and the prefix SHOULD be
428 "%s: IPv4 labeled-unicast NLRI is multicast address %pI4, ignoring",
429 peer
->host
, &p
.u
.prefix4
);
435 if (afi
== AFI_IP6
&& safi
== SAFI_LABELED_UNICAST
) {
436 if (IN6_IS_ADDR_LINKLOCAL(&p
.u
.prefix6
)) {
439 "%s: IPv6 labeled-unicast NLRI is link-local address %pI6, ignoring",
440 peer
->host
, &p
.u
.prefix6
);
445 if (IN6_IS_ADDR_MULTICAST(&p
.u
.prefix6
)) {
448 "%s: IPv6 unicast NLRI is multicast address %pI6, ignoring",
449 peer
->host
, &p
.u
.prefix6
);
456 bgp_update(peer
, &p
, addpath_id
, attr
, packet
->afi
,
457 safi
, ZEBRA_ROUTE_BGP
, BGP_ROUTE_NORMAL
,
458 NULL
, &label
, 1, 0, NULL
);
460 bgp_withdraw(peer
, &p
, addpath_id
, attr
, packet
->afi
,
461 SAFI_UNICAST
, ZEBRA_ROUTE_BGP
,
462 BGP_ROUTE_NORMAL
, NULL
, &label
, 1, NULL
);
466 /* Packet length consistency check. */
470 "%s [Error] Update packet error / L-U (%td data remaining after parsing)",
471 peer
->host
, lim
- pnt
);
472 return BGP_NLRI_PARSE_ERROR_PACKET_LENGTH
;
475 return BGP_NLRI_PARSE_OK
;