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 "dynamic-string.h"
31 #include "poll-loop.h"
37 VLOG_DEFINE_THIS_MODULE(cfm);
39 #define CFM_MAX_RMPS 256
41 /* Ethernet destination address of CCM packets. */
42 static const uint8_t eth_addr_ccm[6] = { 0x01, 0x80, 0xC2, 0x00, 0x00, 0x30 };
43 static const uint8_t eth_addr_ccm_x[6] = {
44 0x01, 0x23, 0x20, 0x00, 0x00, 0x30
47 #define ETH_TYPE_CFM 0x8902
49 /* A 'ccm' represents a Continuity Check Message from the 802.1ag
50 * specification. Continuity Check Messages are broadcast periodically so that
51 * hosts can determine whom they have connectivity to. */
53 #define CCM_MAID_LEN 48
54 #define CCM_OPCODE 1 /* CFM message opcode meaning CCM. */
55 #define CCM_RDI_MASK 0x80
57 uint8_t mdlevel_version; /* MD Level and Version */
63 uint8_t maid[CCM_MAID_LEN];
65 /* Defined by ITU-T Y.1731 should be zero */
66 ovs_be16 interval_ms_x; /* Transmission interval in ms. */
68 } __attribute__((packed));
69 BUILD_ASSERT_DECL(CCM_LEN == sizeof(struct ccm));
72 char *name; /* Name of this CFM object. */
73 struct hmap_node hmap_node; /* Node in all_cfms list. */
76 bool extended; /* Extended mode. */
77 bool fault; /* Indicates connectivity fault. */
78 bool unexpected_recv; /* Received an unexpected CCM. */
80 uint32_t seq; /* The sequence number of our last CCM. */
81 uint8_t ccm_interval; /* The CCM transmission interval. */
82 int ccm_interval_ms; /* 'ccm_interval' in milliseconds. */
83 uint8_t maid[CCM_MAID_LEN]; /* The MAID of this CFM. */
85 struct timer tx_timer; /* Send CCM when expired. */
86 struct timer fault_timer; /* Check for faults when expired. */
88 struct hmap remote_mps; /* Remote MPs. */
91 /* Remote MPs represent foreign network entities that are configured to have
92 * the same MAID as this CFM instance. */
94 uint16_t mpid; /* The Maintenance Point ID of this 'remote_mp'. */
95 struct hmap_node node; /* Node in 'remote_mps' map. */
97 bool recv; /* CCM was received since last fault check. */
98 bool rdi; /* Remote Defect Indicator. Indicates remote_mp isn't
99 receiving CCMs that it's expecting to. */
102 static struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(5, 20);
103 static struct hmap all_cfms = HMAP_INITIALIZER(&all_cfms);
105 static void cfm_unixctl_show(struct unixctl_conn *, const char *args,
108 static const uint8_t *
109 cfm_ccm_addr(const struct cfm *cfm)
111 return cfm->extended ? eth_addr_ccm_x : eth_addr_ccm;
115 cfm_generate_maid(struct cfm *cfm)
117 const char *ovs_md_name = "ovs";
118 const char *ovs_ma_name = "ovs";
120 size_t md_len, ma_len;
122 memset(cfm->maid, 0, CCM_MAID_LEN);
124 md_len = strlen(ovs_md_name);
125 ma_len = strlen(ovs_ma_name);
127 assert(md_len && ma_len && md_len + ma_len + 4 <= CCM_MAID_LEN);
129 cfm->maid[0] = 4; /* MD name string format. */
130 cfm->maid[1] = md_len; /* MD name size. */
131 memcpy(&cfm->maid[2], ovs_md_name, md_len); /* MD name. */
133 ma_p = cfm->maid + 2 + md_len;
134 ma_p[0] = 2; /* MA name string format. */
135 ma_p[1] = ma_len; /* MA name size. */
136 memcpy(&ma_p[2], ovs_ma_name, ma_len); /* MA name. */
140 ccm_interval_to_ms(uint8_t interval)
143 case 0: NOT_REACHED(); /* Explicitly not supported by 802.1ag. */
144 case 1: return 3; /* Not recommended due to timer resolution. */
145 case 2: return 10; /* Not recommended due to timer resolution. */
148 case 5: return 10000;
149 case 6: return 60000;
150 case 7: return 600000;
151 default: NOT_REACHED(); /* Explicitly not supported by 802.1ag. */
158 cfm_fault_interval(struct cfm *cfm)
160 /* According to the 802.1ag specification we should assume every other MP
161 * with the same MAID has the same transmission interval that we have. If
162 * an MP has a different interval, cfm_process_heartbeat will register it
163 * as a fault (likely due to a configuration error). Thus we can check all
164 * MPs at once making this quite a bit simpler.
166 * According to the specification we should check when (ccm_interval_ms *
167 * 3.5)ms have passed. */
168 return (cfm->ccm_interval_ms * 7) / 2;
172 ms_to_ccm_interval(int interval_ms)
176 for (i = 7; i > 0; i--) {
177 if (ccm_interval_to_ms(i) <= interval_ms) {
186 hash_mpid(uint8_t mpid)
188 return hash_int(mpid, 0);
192 cfm_is_valid_mpid(uint32_t mpid)
194 /* 802.1ag specification requires MPIDs to be within the range [1, 8191] */
195 return mpid >= 1 && mpid <= 8191;
198 static struct remote_mp *
199 lookup_remote_mp(const struct cfm *cfm, uint16_t mpid)
201 struct remote_mp *rmp;
203 HMAP_FOR_EACH_IN_BUCKET (rmp, node, hash_mpid(mpid), &cfm->remote_mps) {
204 if (rmp->mpid == mpid) {
215 unixctl_command_register("cfm/show", cfm_unixctl_show, NULL);
218 /* Allocates a 'cfm' object called 'name'. 'cfm' should be initialized by
219 * cfm_configure() before use. */
221 cfm_create(const char *name)
225 cfm = xzalloc(sizeof *cfm);
226 cfm->name = xstrdup(name);
227 hmap_init(&cfm->remote_mps);
228 cfm_generate_maid(cfm);
229 hmap_insert(&all_cfms, &cfm->hmap_node, hash_string(cfm->name, 0));
234 cfm_destroy(struct cfm *cfm)
236 struct remote_mp *rmp, *rmp_next;
242 HMAP_FOR_EACH_SAFE (rmp, rmp_next, node, &cfm->remote_mps) {
243 hmap_remove(&cfm->remote_mps, &rmp->node);
247 hmap_destroy(&cfm->remote_mps);
248 hmap_remove(&all_cfms, &cfm->hmap_node);
253 /* Should be run periodically to update fault statistics messages. */
255 cfm_run(struct cfm *cfm)
257 if (timer_expired(&cfm->fault_timer)) {
258 long long int interval = cfm_fault_interval(cfm);
259 struct remote_mp *rmp, *rmp_next;
261 cfm->fault = cfm->unexpected_recv;
262 cfm->unexpected_recv = false;
264 HMAP_FOR_EACH_SAFE (rmp, rmp_next, node, &cfm->remote_mps) {
267 VLOG_DBG("%s: No CCM from RMP %"PRIu16" in the last %lldms",
268 cfm->name, rmp->mpid, interval);
269 hmap_remove(&cfm->remote_mps, &rmp->node);
274 if (rmp->mpid == cfm->mpid) {
275 VLOG_WARN_RL(&rl, "%s: Received CCM with local MPID (%d)",
276 cfm->name, rmp->mpid);
281 VLOG_DBG("%s: RDI bit flagged from RMP %"PRIu16, cfm->name,
288 if (hmap_is_empty(&cfm->remote_mps)) {
292 timer_set_duration(&cfm->fault_timer, interval);
296 /* Should be run periodically to check if the CFM module has a CCM message it
299 cfm_should_send_ccm(struct cfm *cfm)
301 return timer_expired(&cfm->tx_timer);
304 /* Composes a CCM message into 'packet'. Messages generated with this function
305 * should be sent whenever cfm_should_send_ccm() indicates. */
307 cfm_compose_ccm(struct cfm *cfm, struct ofpbuf *packet,
308 uint8_t eth_src[ETH_ADDR_LEN])
312 timer_set_duration(&cfm->tx_timer, cfm->ccm_interval_ms);
313 ccm = eth_compose(packet, cfm_ccm_addr(cfm), eth_src, ETH_TYPE_CFM,
315 ccm->mdlevel_version = 0;
316 ccm->opcode = CCM_OPCODE;
317 ccm->tlv_offset = 70;
318 ccm->seq = htonl(++cfm->seq);
319 ccm->mpid = htons(cfm->mpid);
320 ccm->flags = cfm->ccm_interval;
321 memcpy(ccm->maid, cfm->maid, sizeof ccm->maid);
322 memset(ccm->zero, 0, sizeof ccm->zero);
324 if (cfm->ccm_interval == 0) {
325 assert(cfm->extended);
326 ccm->interval_ms_x = htons(cfm->ccm_interval_ms);
329 if (hmap_is_empty(&cfm->remote_mps)) {
330 ccm->flags |= CCM_RDI_MASK;
335 cfm_wait(struct cfm *cfm)
338 timer_wait(&cfm->tx_timer);
339 timer_wait(&cfm->fault_timer);
342 /* Configures 'cfm' with settings from 's'. */
344 cfm_configure(struct cfm *cfm, const struct cfm_settings *s)
349 if (!cfm_is_valid_mpid(s->mpid) || s->interval <= 0) {
354 cfm->extended = s->extended;
355 interval = ms_to_ccm_interval(s->interval);
356 interval_ms = ccm_interval_to_ms(interval);
358 if (cfm->extended && interval_ms != s->interval) {
360 interval_ms = MIN(s->interval, UINT16_MAX);
363 if (interval != cfm->ccm_interval || interval_ms != cfm->ccm_interval_ms) {
364 cfm->ccm_interval = interval;
365 cfm->ccm_interval_ms = interval_ms;
367 timer_set_expired(&cfm->tx_timer);
368 timer_set_duration(&cfm->fault_timer, cfm_fault_interval(cfm));
374 /* Returns true if 'cfm' should process packets from 'flow'. */
376 cfm_should_process_flow(const struct cfm *cfm, const struct flow *flow)
378 return (ntohs(flow->dl_type) == ETH_TYPE_CFM
379 && eth_addr_equals(flow->dl_dst, cfm_ccm_addr(cfm)));
382 /* Updates internal statistics relevant to packet 'p'. Should be called on
383 * every packet whose flow returned true when passed to
384 * cfm_should_process_flow. */
386 cfm_process_heartbeat(struct cfm *cfm, const struct ofpbuf *p)
389 struct eth_header *eth;
392 ccm = ofpbuf_at(p, (uint8_t *)p->l3 - (uint8_t *)p->data, CCM_LEN);
395 VLOG_INFO_RL(&rl, "%s: Received an unparseable 802.1ag CCM heartbeat.",
400 if (ccm->opcode != CCM_OPCODE) {
401 VLOG_INFO_RL(&rl, "%s: Received an unsupported 802.1ag message. "
402 "(opcode %u)", cfm->name, ccm->opcode);
406 /* According to the 802.1ag specification, reception of a CCM with an
407 * incorrect ccm_interval, unexpected MAID, or unexpected MPID should
408 * trigger a fault. We ignore this requirement for several reasons.
410 * Faults can cause a controller or Open vSwitch to make potentially
411 * expensive changes to the network topology. It seems prudent to trigger
412 * them judiciously, especially when CFM is used to check slave status of
413 * bonds. Furthermore, faults can be maliciously triggered by crafting
415 if (memcmp(ccm->maid, cfm->maid, sizeof ccm->maid)) {
416 cfm->unexpected_recv = true;
417 VLOG_WARN_RL(&rl, "%s: Received unexpected remote MAID from MAC "
418 ETH_ADDR_FMT, cfm->name, ETH_ADDR_ARGS(eth->eth_src));
420 uint16_t ccm_mpid = ntohs(ccm->mpid);
421 uint8_t ccm_interval = ccm->flags & 0x7;
422 bool ccm_rdi = ccm->flags & CCM_RDI_MASK;
423 uint16_t ccm_interval_ms_x = ntohs(ccm->interval_ms_x);
425 struct remote_mp *rmp;
427 if (ccm_interval != cfm->ccm_interval) {
428 VLOG_WARN_RL(&rl, "%s: received a CCM with an invalid interval"
429 " (%"PRIu8") from RMP %"PRIu16, cfm->name,
430 ccm_interval, ccm_mpid);
433 if (cfm->extended && ccm_interval == 0
434 && ccm_interval_ms_x != cfm->ccm_interval_ms) {
435 VLOG_WARN_RL(&rl, "%s: received a CCM with an invalid extended"
436 " interval (%"PRIu16"ms) from RMP %"PRIu16, cfm->name,
437 ccm_interval_ms_x, ccm_mpid);
440 rmp = lookup_remote_mp(cfm, ccm_mpid);
444 } else if (hmap_count(&cfm->remote_mps) < CFM_MAX_RMPS) {
445 rmp = xmalloc(sizeof *rmp);
446 rmp->mpid = ccm_mpid;
449 hmap_insert(&cfm->remote_mps, &rmp->node, hash_mpid(rmp->mpid));
451 cfm->unexpected_recv = true;
452 VLOG_WARN_RL(&rl, "%s: dropped CCM with MPID %d from MAC "
453 ETH_ADDR_FMT, cfm->name, ccm_mpid,
454 ETH_ADDR_ARGS(eth->eth_src));
457 VLOG_DBG("%s: Received CCM (seq %"PRIu32") (mpid %"PRIu16")"
458 " (interval %"PRIu8") (RDI %s)", cfm->name, ntohl(ccm->seq),
459 ccm_mpid, ccm_interval, ccm_rdi ? "true" : "false");
463 /* Gets the fault status of 'cfm'. Returns true when 'cfm' has detected
464 * connectivity problems, false otherwise. */
466 cfm_get_fault(const struct cfm *cfm)
472 cfm_find(const char *name)
476 HMAP_FOR_EACH_WITH_HASH (cfm, hmap_node, hash_string(name, 0), &all_cfms) {
477 if (!strcmp(cfm->name, name)) {
485 cfm_unixctl_show(struct unixctl_conn *conn,
486 const char *args, void *aux OVS_UNUSED)
488 struct ds ds = DS_EMPTY_INITIALIZER;
489 const struct cfm *cfm;
490 struct remote_mp *rmp;
492 cfm = cfm_find(args);
494 unixctl_command_reply(conn, 501, "no such CFM object");
498 ds_put_format(&ds, "MPID %"PRIu16":%s%s\n", cfm->mpid,
499 cfm->fault ? " fault" : "",
500 cfm->unexpected_recv ? " unexpected_recv" : "");
502 ds_put_format(&ds, "\tinterval: %dms\n", cfm->ccm_interval_ms);
503 ds_put_format(&ds, "\tnext CCM tx: %lldms\n",
504 timer_msecs_until_expired(&cfm->tx_timer));
505 ds_put_format(&ds, "\tnext fault check: %lldms\n",
506 timer_msecs_until_expired(&cfm->fault_timer));
508 ds_put_cstr(&ds, "\n");
509 HMAP_FOR_EACH (rmp, node, &cfm->remote_mps) {
510 ds_put_format(&ds, "Remote MPID %"PRIu16":%s\n", rmp->mpid,
511 rmp->rdi ? " rdi" : "");
512 ds_put_format(&ds, "\trecv since check: %s",
513 rmp->recv ? "true" : "false");
516 unixctl_command_reply(conn, 200, ds_cstr(&ds));