2 * Addpath TX ID selection, and related utilities
3 * Copyright (C) 2018 Amazon.com, Inc. or its affiliates
5 * This program is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License as published by the Free
7 * Software Foundation; either version 2 of the License, or (at your option)
10 * This program is distributed in the hope that it will be useful, but WITHOUT
11 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
12 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
15 * You should have received a copy of the GNU General Public License along
16 * with this program; see the file COPYING; if not, write to the Free Software
17 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
24 #include "bgp_addpath.h"
25 #include "bgp_route.h"
27 static const struct bgp_addpath_strategy_names strat_names
[BGP_ADDPATH_MAX
] = {
29 .config_name
= "addpath-tx-all-paths",
31 .human_description
= "Advertise all paths via addpath",
32 .type_json_name
= "addpathTxAllPaths",
33 .id_json_name
= "addpathTxIdAll"
36 .config_name
= "addpath-tx-bestpath-per-AS",
37 .human_name
= "Best-Per-AS",
38 .human_description
= "Advertise bestpath per AS via addpath",
39 .type_json_name
= "addpathTxBestpathPerAS",
40 .id_json_name
= "addpathTxIdBestPerAS"
44 static const struct bgp_addpath_strategy_names unknown_names
= {
45 .config_name
= "addpath-tx-unknown",
46 .human_name
= "Unknown-Addpath-Strategy",
47 .human_description
= "Unknown Addpath Strategy",
48 .type_json_name
= "addpathTxUnknown",
49 .id_json_name
= "addpathTxIdUnknown"
53 * Returns a structure full of strings associated with an addpath type. Will
56 const struct bgp_addpath_strategy_names
*
57 bgp_addpath_names(enum bgp_addpath_strat strat
)
59 if (strat
< BGP_ADDPATH_MAX
)
60 return &(strat_names
[strat
]);
62 return &unknown_names
;
66 * Returns if any peer is transmitting addpaths for a given afi/safi.
68 bool bgp_addpath_is_addpath_used(struct bgp_addpath_bgp_data
*d
, afi_t afi
,
71 return d
->total_peercount
[afi
][safi
] > 0;
75 * Initialize the BGP instance level data for addpath.
77 void bgp_addpath_init_bgp_data(struct bgp_addpath_bgp_data
*d
)
83 FOREACH_AFI_SAFI (afi
, safi
) {
84 for (i
= 0; i
< BGP_ADDPATH_MAX
; i
++) {
85 d
->id_allocators
[afi
][safi
][i
] = NULL
;
86 d
->peercount
[afi
][safi
][i
] = 0;
88 d
->total_peercount
[afi
][safi
] = 0;
93 * Free up resources associated with BGP route info structures.
95 void bgp_addpath_free_info_data(struct bgp_addpath_info_data
*d
,
96 struct bgp_addpath_node_data
*nd
)
100 for (i
= 0; i
< BGP_ADDPATH_MAX
; i
++) {
101 if (d
->addpath_tx_id
[i
] != IDALLOC_INVALID
)
102 idalloc_free_to_pool(&nd
->free_ids
[i
],
103 d
->addpath_tx_id
[i
]);
108 * Return the addpath ID used to send a particular route, to a particular peer,
109 * in a particular AFI/SAFI.
111 uint32_t bgp_addpath_id_for_peer(struct peer
*peer
, afi_t afi
, safi_t safi
,
112 struct bgp_addpath_info_data
*d
)
114 if (peer
->addpath_type
[afi
][safi
] < BGP_ADDPATH_MAX
)
115 return d
->addpath_tx_id
[peer
->addpath_type
[afi
][safi
]];
117 return IDALLOC_INVALID
;
121 * Returns true if the path has an assigned addpath ID for any of the addpath
124 bool bgp_addpath_info_has_ids(struct bgp_addpath_info_data
*d
)
128 for (i
= 0; i
< BGP_ADDPATH_MAX
; i
++)
129 if (d
->addpath_tx_id
[i
] != 0)
136 * Releases any ID's associated with the BGP prefix.
138 void bgp_addpath_free_node_data(struct bgp_addpath_bgp_data
*bd
,
139 struct bgp_addpath_node_data
*nd
, afi_t afi
,
144 for (i
= 0; i
< BGP_ADDPATH_MAX
; i
++) {
145 idalloc_drain_pool(bd
->id_allocators
[afi
][safi
][i
],
151 * Check to see if the addpath strategy requires DMED to be configured to work.
153 bool bgp_addpath_dmed_required(int strategy
)
155 return strategy
== BGP_ADDPATH_BEST_PER_AS
;
159 * Return true if this is a path we should advertise due to a
160 * configured addpath-tx knob
162 bool bgp_addpath_tx_path(enum bgp_addpath_strat strat
, struct bgp_path_info
*pi
)
165 case BGP_ADDPATH_NONE
:
167 case BGP_ADDPATH_ALL
:
169 case BGP_ADDPATH_BEST_PER_AS
:
170 if (CHECK_FLAG(pi
->flags
, BGP_PATH_DMED_SELECTED
))
179 static void bgp_addpath_flush_type_rn(struct bgp
*bgp
, afi_t afi
, safi_t safi
,
180 enum bgp_addpath_strat addpath_type
,
181 struct bgp_dest
*dest
)
183 struct bgp_path_info
*pi
;
186 bgp
->tx_addpath
.id_allocators
[afi
][safi
][addpath_type
],
187 &(dest
->tx_addpath
.free_ids
[addpath_type
]));
188 for (pi
= bgp_dest_get_bgp_path_info(dest
); pi
; pi
= pi
->next
) {
189 if (pi
->tx_addpath
.addpath_tx_id
[addpath_type
]
190 != IDALLOC_INVALID
) {
193 .id_allocators
[afi
][safi
][addpath_type
],
194 pi
->tx_addpath
.addpath_tx_id
[addpath_type
]);
195 pi
->tx_addpath
.addpath_tx_id
[addpath_type
] =
202 * Purge all addpath ID's on a BGP instance associated with the addpath
203 * strategy, and afi/safi combination. This lets us let go of all memory held to
204 * track ID numbers associated with an addpath type not in use. Since
205 * post-bestpath ID processing is skipped for types not used, this is the only
206 * chance to free this data.
208 static void bgp_addpath_flush_type(struct bgp
*bgp
, afi_t afi
, safi_t safi
,
209 enum bgp_addpath_strat addpath_type
)
211 struct bgp_dest
*dest
, *ndest
;
213 for (dest
= bgp_table_top(bgp
->rib
[afi
][safi
]); dest
;
214 dest
= bgp_route_next(dest
)) {
215 if (safi
== SAFI_MPLS_VPN
) {
216 struct bgp_table
*table
;
218 table
= bgp_dest_get_bgp_table_info(dest
);
222 for (ndest
= bgp_table_top(table
); ndest
;
223 ndest
= bgp_route_next(ndest
))
224 bgp_addpath_flush_type_rn(bgp
, afi
, safi
,
225 addpath_type
, ndest
);
227 bgp_addpath_flush_type_rn(bgp
, afi
, safi
, addpath_type
,
232 idalloc_destroy(bgp
->tx_addpath
.id_allocators
[afi
][safi
][addpath_type
]);
233 bgp
->tx_addpath
.id_allocators
[afi
][safi
][addpath_type
] = NULL
;
237 * Allocate an Addpath ID for the given type on a path, if necessary.
239 static void bgp_addpath_populate_path(struct id_alloc
*allocator
,
240 struct bgp_path_info
*path
,
241 enum bgp_addpath_strat addpath_type
)
243 if (bgp_addpath_tx_path(addpath_type
, path
)) {
244 path
->tx_addpath
.addpath_tx_id
[addpath_type
] =
245 idalloc_allocate(allocator
);
250 * Compute addpath ID's on a BGP instance associated with the addpath strategy,
251 * and afi/safi combination. Since we won't waste the time computing addpath IDs
252 * for unused strategies, the first time a peer is configured to use a strategy,
253 * we have to backfill the data.
255 static void bgp_addpath_populate_type(struct bgp
*bgp
, afi_t afi
, safi_t safi
,
256 enum bgp_addpath_strat addpath_type
)
258 struct bgp_dest
*dest
, *ndest
;
260 struct id_alloc
*allocator
;
262 snprintf(buf
, sizeof(buf
), "Addpath ID Allocator %s:%d/%d",
263 bgp_addpath_names(addpath_type
)->config_name
, (int)afi
,
265 buf
[sizeof(buf
) - 1] = '\0';
266 zlog_info("Computing addpath IDs for addpath type %s",
267 bgp_addpath_names(addpath_type
)->human_name
);
269 bgp
->tx_addpath
.id_allocators
[afi
][safi
][addpath_type
] =
272 idalloc_reserve(bgp
->tx_addpath
.id_allocators
[afi
][safi
][addpath_type
],
273 BGP_ADDPATH_TX_ID_FOR_DEFAULT_ORIGINATE
);
275 allocator
= bgp
->tx_addpath
.id_allocators
[afi
][safi
][addpath_type
];
277 for (dest
= bgp_table_top(bgp
->rib
[afi
][safi
]); dest
;
278 dest
= bgp_route_next(dest
)) {
279 struct bgp_path_info
*bi
;
281 if (safi
== SAFI_MPLS_VPN
) {
282 struct bgp_table
*table
;
284 table
= bgp_dest_get_bgp_table_info(dest
);
288 for (ndest
= bgp_table_top(table
); ndest
;
289 ndest
= bgp_route_next(ndest
))
290 for (bi
= bgp_dest_get_bgp_path_info(ndest
); bi
;
292 bgp_addpath_populate_path(allocator
, bi
,
295 for (bi
= bgp_dest_get_bgp_path_info(dest
); bi
;
297 bgp_addpath_populate_path(allocator
, bi
,
304 * Handle updates to a peer or group's addpath strategy. If after adjusting
305 * counts a addpath strategy is in use for the first time, or no longer in use,
306 * the IDs for that strategy will be populated or flushed.
308 void bgp_addpath_type_changed(struct bgp
*bgp
)
312 struct listnode
*node
, *nnode
;
314 int peer_count
[AFI_MAX
][SAFI_MAX
][BGP_ADDPATH_MAX
];
315 enum bgp_addpath_strat type
;
317 FOREACH_AFI_SAFI(afi
, safi
) {
318 for (type
=0; type
<BGP_ADDPATH_MAX
; type
++) {
319 peer_count
[afi
][safi
][type
] = 0;
321 bgp
->tx_addpath
.total_peercount
[afi
][safi
] = 0;
324 for (ALL_LIST_ELEMENTS(bgp
->peer
, node
, nnode
, peer
)) {
325 FOREACH_AFI_SAFI(afi
, safi
) {
326 type
= peer
->addpath_type
[afi
][safi
];
327 if (type
!= BGP_ADDPATH_NONE
) {
328 peer_count
[afi
][safi
][type
] += 1;
329 bgp
->tx_addpath
.total_peercount
[afi
][safi
] += 1;
334 FOREACH_AFI_SAFI(afi
, safi
) {
335 for (type
=0; type
<BGP_ADDPATH_MAX
; type
++) {
336 int old
= bgp
->tx_addpath
.peercount
[afi
][safi
][type
];
337 int new = peer_count
[afi
][safi
][type
];
339 bgp
->tx_addpath
.peercount
[afi
][safi
][type
] = new;
341 if (old
== 0 && new != 0) {
342 bgp_addpath_populate_type(bgp
, afi
, safi
,
344 } else if (old
!= 0 && new == 0) {
345 bgp_addpath_flush_type(bgp
, afi
, safi
, type
);
352 * Change the addpath type assigned to a peer, or peer group. In addition to
353 * adjusting the counts, peer sessions will be reset as needed to make the
354 * change take effect.
356 void bgp_addpath_set_peer_type(struct peer
*peer
, afi_t afi
, safi_t safi
,
357 enum bgp_addpath_strat addpath_type
)
359 struct bgp
*bgp
= peer
->bgp
;
360 enum bgp_addpath_strat old_type
= peer
->addpath_type
[afi
][safi
];
361 struct listnode
*node
, *nnode
;
362 struct peer
*tmp_peer
;
363 struct peer_group
*group
;
365 if (addpath_type
== old_type
)
368 if (addpath_type
== BGP_ADDPATH_NONE
&& peer
->group
&&
369 !CHECK_FLAG(peer
->sflags
, PEER_STATUS_GROUP
)) {
370 /* A "no" config on a group member inherits group */
371 addpath_type
= peer
->group
->conf
->addpath_type
[afi
][safi
];
374 peer
->addpath_type
[afi
][safi
] = addpath_type
;
376 bgp_addpath_type_changed(bgp
);
378 if (addpath_type
!= BGP_ADDPATH_NONE
) {
379 if (bgp_addpath_dmed_required(addpath_type
)) {
380 if (!CHECK_FLAG(bgp
->flags
,
381 BGP_FLAG_DETERMINISTIC_MED
)) {
383 "%s: enabling bgp deterministic-med, this is required for addpath-tx-bestpath-per-AS",
386 BGP_FLAG_DETERMINISTIC_MED
);
387 bgp_recalculate_all_bestpaths(bgp
);
392 zlog_info("Resetting peer %s%s due to change in addpath config",
393 CHECK_FLAG(peer
->sflags
, PEER_STATUS_GROUP
) ? "group " : "",
396 if (CHECK_FLAG(peer
->sflags
, PEER_STATUS_GROUP
)) {
399 /* group will be null as peer_group_delete calls peer_delete on
400 * group->conf. That peer_delete will eventuallly end up here
401 * if the group was configured to tx addpaths.
404 for (ALL_LIST_ELEMENTS(group
->peer
, node
, nnode
,
406 if (tmp_peer
->addpath_type
[afi
][safi
] ==
408 bgp_addpath_set_peer_type(tmp_peer
,
416 peer_change_action(peer
, afi
, safi
, peer_change_reset
);
422 * Intended to run after bestpath. This function will take TX IDs from paths
423 * that no longer need them, and give them to paths that do. This prevents
424 * best-per-as updates from needing to do a separate withdraw and update just to
425 * swap out which path is sent.
427 void bgp_addpath_update_ids(struct bgp
*bgp
, struct bgp_dest
*bn
, afi_t afi
,
431 struct bgp_path_info
*pi
;
432 struct id_alloc_pool
**pool_ptr
;
434 for (i
= 0; i
< BGP_ADDPATH_MAX
; i
++) {
435 struct id_alloc
*alloc
=
436 bgp
->tx_addpath
.id_allocators
[afi
][safi
][i
];
437 pool_ptr
= &(bn
->tx_addpath
.free_ids
[i
]);
439 if (bgp
->tx_addpath
.peercount
[afi
][safi
][i
] == 0)
442 /* Free Unused IDs back to the pool.*/
443 for (pi
= bgp_dest_get_bgp_path_info(bn
); pi
; pi
= pi
->next
) {
444 if (pi
->tx_addpath
.addpath_tx_id
[i
] != IDALLOC_INVALID
445 && !bgp_addpath_tx_path(i
, pi
)) {
446 idalloc_free_to_pool(pool_ptr
,
447 pi
->tx_addpath
.addpath_tx_id
[i
]);
448 pi
->tx_addpath
.addpath_tx_id
[i
] =
453 /* Give IDs to paths that need them (pulling from the pool) */
454 for (pi
= bgp_dest_get_bgp_path_info(bn
); pi
; pi
= pi
->next
) {
455 if (pi
->tx_addpath
.addpath_tx_id
[i
] == IDALLOC_INVALID
456 && bgp_addpath_tx_path(i
, pi
)) {
457 pi
->tx_addpath
.addpath_tx_id
[i
] =
458 idalloc_allocate_prefer_pool(
463 /* Free any IDs left in the pool to the main allocator */
464 idalloc_drain_pool(alloc
, pool_ptr
);