2 * Copyright (c) 2010, 2011 Nicira Networks.
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at:
8 * http://www.apache.org/licenses/LICENSE-2.0
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
25 #include "byte-order.h"
26 #include "dynamic-string.h"
32 #include "poll-loop.h"
38 VLOG_DEFINE_THIS_MODULE(cfm);
40 #define CFM_MAX_RMPS 256
42 /* Ethernet destination address of CCM packets. */
43 static const uint8_t eth_addr_ccm[6] = { 0x01, 0x80, 0xC2, 0x00, 0x00, 0x30 };
44 static const uint8_t eth_addr_ccm_x[6] = {
45 0x01, 0x23, 0x20, 0x00, 0x00, 0x30
48 #define ETH_TYPE_CFM 0x8902
50 /* A 'ccm' represents a Continuity Check Message from the 802.1ag
51 * specification. Continuity Check Messages are broadcast periodically so that
52 * hosts can determine whom they have connectivity to.
54 * The minimum length of a CCM as specified by IEEE 802.1ag is 75 bytes.
55 * Previous versions of Open vSwitch generated 74-byte CCM messages, so we
56 * accept such messages too. */
58 #define CCM_ACCEPT_LEN 74
59 #define CCM_MAID_LEN 48
60 #define CCM_OPCODE 1 /* CFM message opcode meaning CCM. */
61 #define CCM_RDI_MASK 0x80
63 uint8_t mdlevel_version; /* MD Level and Version */
69 uint8_t maid[CCM_MAID_LEN];
71 /* Defined by ITU-T Y.1731 should be zero */
72 ovs_be16 interval_ms_x; /* Transmission interval in ms. */
73 ovs_be64 mpid64; /* MPID in extended mode. */
74 uint8_t opdown; /* Operationally down. */
79 } __attribute__((packed));
80 BUILD_ASSERT_DECL(CCM_LEN == sizeof(struct ccm));
83 char *name; /* Name of this CFM object. */
84 struct hmap_node hmap_node; /* Node in all_cfms list. */
87 bool extended; /* Extended mode. */
88 bool fault; /* Indicates connectivity fault. */
89 bool unexpected_recv; /* Received an unexpected CCM. */
90 bool opup; /* Operational State. */
91 bool remote_opup; /* Remote Operational State. */
93 uint32_t seq; /* The sequence number of our last CCM. */
94 uint8_t ccm_interval; /* The CCM transmission interval. */
95 int ccm_interval_ms; /* 'ccm_interval' in milliseconds. */
96 uint16_t ccm_vlan; /* Vlan tag of CCM PDUs. */
97 uint8_t maid[CCM_MAID_LEN]; /* The MAID of this CFM. */
99 struct timer tx_timer; /* Send CCM when expired. */
100 struct timer fault_timer; /* Check for faults when expired. */
102 struct hmap remote_mps; /* Remote MPs. */
104 /* Result of cfm_get_remote_mpids(). Updated only during fault check to
106 uint64_t *rmps_array; /* Cache of remote_mps. */
107 size_t rmps_array_len; /* Number of rmps in 'rmps_array'. */
110 /* Remote MPs represent foreign network entities that are configured to have
111 * the same MAID as this CFM instance. */
113 uint64_t mpid; /* The Maintenance Point ID of this 'remote_mp'. */
114 struct hmap_node node; /* Node in 'remote_mps' map. */
116 bool recv; /* CCM was received since last fault check. */
117 bool rdi; /* Remote Defect Indicator. Indicates remote_mp isn't
118 receiving CCMs that it's expecting to. */
119 bool opup; /* Operational State. */
122 static struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(5, 20);
123 static struct hmap all_cfms = HMAP_INITIALIZER(&all_cfms);
125 static void cfm_unixctl_show(struct unixctl_conn *, const char *args,
128 static const uint8_t *
129 cfm_ccm_addr(const struct cfm *cfm)
131 return cfm->extended ? eth_addr_ccm_x : eth_addr_ccm;
135 cfm_generate_maid(struct cfm *cfm)
137 const char *ovs_md_name = "ovs";
138 const char *ovs_ma_name = "ovs";
140 size_t md_len, ma_len;
142 memset(cfm->maid, 0, CCM_MAID_LEN);
144 md_len = strlen(ovs_md_name);
145 ma_len = strlen(ovs_ma_name);
147 assert(md_len && ma_len && md_len + ma_len + 4 <= CCM_MAID_LEN);
149 cfm->maid[0] = 4; /* MD name string format. */
150 cfm->maid[1] = md_len; /* MD name size. */
151 memcpy(&cfm->maid[2], ovs_md_name, md_len); /* MD name. */
153 ma_p = cfm->maid + 2 + md_len;
154 ma_p[0] = 2; /* MA name string format. */
155 ma_p[1] = ma_len; /* MA name size. */
156 memcpy(&ma_p[2], ovs_ma_name, ma_len); /* MA name. */
160 ccm_interval_to_ms(uint8_t interval)
163 case 0: NOT_REACHED(); /* Explicitly not supported by 802.1ag. */
164 case 1: return 3; /* Not recommended due to timer resolution. */
165 case 2: return 10; /* Not recommended due to timer resolution. */
168 case 5: return 10000;
169 case 6: return 60000;
170 case 7: return 600000;
171 default: NOT_REACHED(); /* Explicitly not supported by 802.1ag. */
178 cfm_fault_interval(struct cfm *cfm)
180 /* According to the 802.1ag specification we should assume every other MP
181 * with the same MAID has the same transmission interval that we have. If
182 * an MP has a different interval, cfm_process_heartbeat will register it
183 * as a fault (likely due to a configuration error). Thus we can check all
184 * MPs at once making this quite a bit simpler.
186 * According to the specification we should check when (ccm_interval_ms *
187 * 3.5)ms have passed. */
188 return (cfm->ccm_interval_ms * 7) / 2;
192 ms_to_ccm_interval(int interval_ms)
196 for (i = 7; i > 0; i--) {
197 if (ccm_interval_to_ms(i) <= interval_ms) {
206 hash_mpid(uint64_t mpid)
208 return hash_bytes(&mpid, sizeof mpid, 0);
212 cfm_is_valid_mpid(bool extended, uint64_t mpid)
214 /* 802.1ag specification requires MPIDs to be within the range [1, 8191].
215 * In extended mode we relax this requirement. */
216 return mpid >= 1 && (extended || mpid <= 8191);
219 static struct remote_mp *
220 lookup_remote_mp(const struct cfm *cfm, uint64_t mpid)
222 struct remote_mp *rmp;
224 HMAP_FOR_EACH_IN_BUCKET (rmp, node, hash_mpid(mpid), &cfm->remote_mps) {
225 if (rmp->mpid == mpid) {
236 unixctl_command_register("cfm/show", "[interface]", cfm_unixctl_show,
240 /* Allocates a 'cfm' object called 'name'. 'cfm' should be initialized by
241 * cfm_configure() before use. */
243 cfm_create(const char *name)
247 cfm = xzalloc(sizeof *cfm);
248 cfm->name = xstrdup(name);
249 hmap_init(&cfm->remote_mps);
250 cfm_generate_maid(cfm);
251 hmap_insert(&all_cfms, &cfm->hmap_node, hash_string(cfm->name, 0));
252 cfm->remote_opup = true;
257 cfm_destroy(struct cfm *cfm)
259 struct remote_mp *rmp, *rmp_next;
265 HMAP_FOR_EACH_SAFE (rmp, rmp_next, node, &cfm->remote_mps) {
266 hmap_remove(&cfm->remote_mps, &rmp->node);
270 hmap_destroy(&cfm->remote_mps);
271 hmap_remove(&all_cfms, &cfm->hmap_node);
272 free(cfm->rmps_array);
277 /* Should be run periodically to update fault statistics messages. */
279 cfm_run(struct cfm *cfm)
281 if (timer_expired(&cfm->fault_timer)) {
282 long long int interval = cfm_fault_interval(cfm);
283 struct remote_mp *rmp, *rmp_next;
285 cfm->fault = cfm->unexpected_recv;
286 cfm->unexpected_recv = false;
288 cfm->rmps_array_len = 0;
289 free(cfm->rmps_array);
290 cfm->rmps_array = xmalloc(hmap_count(&cfm->remote_mps) *
291 sizeof *cfm->rmps_array);
293 cfm->remote_opup = true;
294 HMAP_FOR_EACH_SAFE (rmp, rmp_next, node, &cfm->remote_mps) {
297 VLOG_DBG("%s: no CCM from RMP %"PRIu64" in the last %lldms",
298 cfm->name, rmp->mpid, interval);
299 hmap_remove(&cfm->remote_mps, &rmp->node);
304 if (rmp->mpid == cfm->mpid) {
305 VLOG_WARN_RL(&rl,"%s: received CCM with local MPID"
306 " %"PRIu64, cfm->name, rmp->mpid);
311 VLOG_DBG("%s: RDI bit flagged from RMP %"PRIu64, cfm->name,
317 cfm->remote_opup = rmp->opup;
320 cfm->rmps_array[cfm->rmps_array_len++] = rmp->mpid;
324 if (hmap_is_empty(&cfm->remote_mps)) {
328 timer_set_duration(&cfm->fault_timer, interval);
332 /* Should be run periodically to check if the CFM module has a CCM message it
335 cfm_should_send_ccm(struct cfm *cfm)
337 return timer_expired(&cfm->tx_timer);
340 /* Composes a CCM message into 'packet'. Messages generated with this function
341 * should be sent whenever cfm_should_send_ccm() indicates. */
343 cfm_compose_ccm(struct cfm *cfm, struct ofpbuf *packet,
344 uint8_t eth_src[ETH_ADDR_LEN])
348 timer_set_duration(&cfm->tx_timer, cfm->ccm_interval_ms);
349 eth_compose(packet, cfm_ccm_addr(cfm), eth_src, ETH_TYPE_CFM, sizeof *ccm);
352 eth_push_vlan(packet, htons(cfm->ccm_vlan));
356 ccm->mdlevel_version = 0;
357 ccm->opcode = CCM_OPCODE;
358 ccm->tlv_offset = 70;
359 ccm->seq = htonl(++cfm->seq);
360 ccm->flags = cfm->ccm_interval;
361 memcpy(ccm->maid, cfm->maid, sizeof ccm->maid);
362 memset(ccm->zero, 0, sizeof ccm->zero);
366 ccm->mpid = htons(hash_mpid(cfm->mpid));
367 ccm->mpid64 = htonll(cfm->mpid);
368 ccm->opdown = !cfm->opup;
370 ccm->mpid = htons(cfm->mpid);
371 ccm->mpid64 = htonll(0);
375 if (cfm->ccm_interval == 0) {
376 assert(cfm->extended);
377 ccm->interval_ms_x = htons(cfm->ccm_interval_ms);
380 if (hmap_is_empty(&cfm->remote_mps)) {
381 ccm->flags |= CCM_RDI_MASK;
386 cfm_wait(struct cfm *cfm)
388 timer_wait(&cfm->tx_timer);
389 timer_wait(&cfm->fault_timer);
392 /* Configures 'cfm' with settings from 's'. */
394 cfm_configure(struct cfm *cfm, const struct cfm_settings *s)
399 if (!cfm_is_valid_mpid(s->extended, s->mpid) || s->interval <= 0) {
404 cfm->extended = s->extended;
406 interval = ms_to_ccm_interval(s->interval);
407 interval_ms = ccm_interval_to_ms(interval);
409 cfm->ccm_vlan = s->ccm_vlan & VLAN_VID_MASK;
410 if (cfm->extended && interval_ms != s->interval) {
412 interval_ms = MIN(s->interval, UINT16_MAX);
415 if (interval != cfm->ccm_interval || interval_ms != cfm->ccm_interval_ms) {
416 cfm->ccm_interval = interval;
417 cfm->ccm_interval_ms = interval_ms;
419 timer_set_expired(&cfm->tx_timer);
420 timer_set_duration(&cfm->fault_timer, cfm_fault_interval(cfm));
426 /* Returns true if 'cfm' should process packets from 'flow'. */
428 cfm_should_process_flow(const struct cfm *cfm, const struct flow *flow)
430 return (ntohs(flow->dl_type) == ETH_TYPE_CFM
431 && eth_addr_equals(flow->dl_dst, cfm_ccm_addr(cfm)));
434 /* Updates internal statistics relevant to packet 'p'. Should be called on
435 * every packet whose flow returned true when passed to
436 * cfm_should_process_flow. */
438 cfm_process_heartbeat(struct cfm *cfm, const struct ofpbuf *p)
441 struct eth_header *eth;
444 ccm = ofpbuf_at(p, (uint8_t *)p->l3 - (uint8_t *)p->data, CCM_ACCEPT_LEN);
447 VLOG_INFO_RL(&rl, "%s: Received an unparseable 802.1ag CCM heartbeat.",
452 if (ccm->opcode != CCM_OPCODE) {
453 VLOG_INFO_RL(&rl, "%s: Received an unsupported 802.1ag message. "
454 "(opcode %u)", cfm->name, ccm->opcode);
458 /* According to the 802.1ag specification, reception of a CCM with an
459 * incorrect ccm_interval, unexpected MAID, or unexpected MPID should
460 * trigger a fault. We ignore this requirement for several reasons.
462 * Faults can cause a controller or Open vSwitch to make potentially
463 * expensive changes to the network topology. It seems prudent to trigger
464 * them judiciously, especially when CFM is used to check slave status of
465 * bonds. Furthermore, faults can be maliciously triggered by crafting
467 if (memcmp(ccm->maid, cfm->maid, sizeof ccm->maid)) {
468 cfm->unexpected_recv = true;
469 VLOG_WARN_RL(&rl, "%s: Received unexpected remote MAID from MAC "
470 ETH_ADDR_FMT, cfm->name, ETH_ADDR_ARGS(eth->eth_src));
472 uint8_t ccm_interval = ccm->flags & 0x7;
473 bool ccm_rdi = ccm->flags & CCM_RDI_MASK;
474 uint16_t ccm_interval_ms_x = ntohs(ccm->interval_ms_x);
476 struct remote_mp *rmp;
481 ccm_mpid = ntohll(ccm->mpid64);
482 ccm_opdown = ccm->opdown;
484 ccm_mpid = ntohs(ccm->mpid);
488 if (ccm_interval != cfm->ccm_interval) {
489 VLOG_WARN_RL(&rl, "%s: received a CCM with an invalid interval"
490 " (%"PRIu8") from RMP %"PRIu64, cfm->name,
491 ccm_interval, ccm_mpid);
494 if (cfm->extended && ccm_interval == 0
495 && ccm_interval_ms_x != cfm->ccm_interval_ms) {
496 VLOG_WARN_RL(&rl, "%s: received a CCM with an invalid extended"
497 " interval (%"PRIu16"ms) from RMP %"PRIu64, cfm->name,
498 ccm_interval_ms_x, ccm_mpid);
501 rmp = lookup_remote_mp(cfm, ccm_mpid);
503 if (hmap_count(&cfm->remote_mps) < CFM_MAX_RMPS) {
504 rmp = xmalloc(sizeof *rmp);
505 hmap_insert(&cfm->remote_mps, &rmp->node, hash_mpid(ccm_mpid));
507 cfm->unexpected_recv = true;
509 "%s: dropped CCM with MPID %"PRIu64" from MAC "
510 ETH_ADDR_FMT, cfm->name, ccm_mpid,
511 ETH_ADDR_ARGS(eth->eth_src));
516 rmp->mpid = ccm_mpid;
519 rmp->opup = !ccm_opdown;
522 VLOG_DBG("%s: received CCM (seq %"PRIu32") (mpid %"PRIu64")"
523 " (interval %"PRIu8") (RDI %s)", cfm->name, ntohl(ccm->seq),
524 ccm_mpid, ccm_interval, ccm_rdi ? "true" : "false");
528 /* Gets the fault status of 'cfm'. Returns true when 'cfm' has detected
529 * connectivity problems, false otherwise. */
531 cfm_get_fault(const struct cfm *cfm)
536 /* Gets the operational state of 'cfm'. 'cfm' is considered operationally down
537 * if it has received a CCM with the operationally down bit set from any of its
538 * remote maintenance points. Returns true if 'cfm' is operationally up. False
541 cfm_get_opup(const struct cfm *cfm)
543 return cfm->remote_opup;
546 /* Populates 'rmps' with an array of remote maintenance points reachable by
547 * 'cfm'. The number of remote maintenance points is written to 'n_rmps'.
548 * 'cfm' retains ownership of the array written to 'rmps' */
550 cfm_get_remote_mpids(const struct cfm *cfm, const uint64_t **rmps,
553 *rmps = cfm->rmps_array;
554 *n_rmps = cfm->rmps_array_len;
558 cfm_find(const char *name)
562 HMAP_FOR_EACH_WITH_HASH (cfm, hmap_node, hash_string(name, 0), &all_cfms) {
563 if (!strcmp(cfm->name, name)) {
571 cfm_print_details(struct ds *ds, const struct cfm *cfm)
573 struct remote_mp *rmp;
575 ds_put_format(ds, "---- %s ----\n", cfm->name);
576 ds_put_format(ds, "MPID %"PRIu64":%s%s%s\n", cfm->mpid,
577 cfm->extended ? " extended" : "",
578 cfm->fault ? " fault" : "",
579 cfm->unexpected_recv ? " unexpected_recv" : "");
581 ds_put_format(ds, "\topstate: %s\n", cfm->opup ? "up" : "down");
582 ds_put_format(ds, "\tremote_opstate: %s\n",
583 cfm->remote_opup ? "up" : "down");
584 ds_put_format(ds, "\tinterval: %dms\n", cfm->ccm_interval_ms);
585 ds_put_format(ds, "\tnext CCM tx: %lldms\n",
586 timer_msecs_until_expired(&cfm->tx_timer));
587 ds_put_format(ds, "\tnext fault check: %lldms\n",
588 timer_msecs_until_expired(&cfm->fault_timer));
590 HMAP_FOR_EACH (rmp, node, &cfm->remote_mps) {
591 ds_put_format(ds, "Remote MPID %"PRIu64":%s\n",
593 rmp->rdi ? " rdi" : "");
594 ds_put_format(ds, "\trecv since check: %s\n",
595 rmp->recv ? "true" : "false");
596 ds_put_format(ds, "\topstate: %s\n", rmp->opup? "up" : "down");
601 cfm_unixctl_show(struct unixctl_conn *conn,
602 const char *args, void *aux OVS_UNUSED)
604 struct ds ds = DS_EMPTY_INITIALIZER;
605 const struct cfm *cfm;
608 cfm = cfm_find(args);
610 unixctl_command_reply(conn, 501, "no such CFM object");
613 cfm_print_details(&ds, cfm);
615 HMAP_FOR_EACH (cfm, hmap_node, &all_cfms) {
616 cfm_print_details(&ds, cfm);
620 unixctl_command_reply(conn, 200, ds_cstr(&ds));