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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 #define CCM_MAID_LEN 48
55 #define CCM_OPCODE 1 /* CFM message opcode meaning CCM. */
56 #define CCM_RDI_MASK 0x80
58 uint8_t mdlevel_version
; /* MD Level and Version */
64 uint8_t maid
[CCM_MAID_LEN
];
66 /* Defined by ITU-T Y.1731 should be zero */
67 ovs_be16 interval_ms_x
; /* Transmission interval in ms. */
68 ovs_be64 mpid64
; /* MPID in extended mode. */
70 } __attribute__((packed
));
71 BUILD_ASSERT_DECL(CCM_LEN
== sizeof(struct ccm
));
74 char *name
; /* Name of this CFM object. */
75 struct hmap_node hmap_node
; /* Node in all_cfms list. */
78 bool extended
; /* Extended mode. */
79 bool fault
; /* Indicates connectivity fault. */
80 bool unexpected_recv
; /* Received an unexpected CCM. */
82 uint32_t seq
; /* The sequence number of our last CCM. */
83 uint8_t ccm_interval
; /* The CCM transmission interval. */
84 int ccm_interval_ms
; /* 'ccm_interval' in milliseconds. */
85 uint8_t maid
[CCM_MAID_LEN
]; /* The MAID of this CFM. */
87 struct timer tx_timer
; /* Send CCM when expired. */
88 struct timer fault_timer
; /* Check for faults when expired. */
90 struct hmap remote_mps
; /* Remote MPs. */
92 /* Result of cfm_get_remote_mpids(). Updated only during fault check to
94 uint64_t *rmps_array
; /* Cache of remote_mps. */
95 size_t rmps_array_len
; /* Number of rmps in 'rmps_array'. */
98 /* Remote MPs represent foreign network entities that are configured to have
99 * the same MAID as this CFM instance. */
101 uint64_t mpid
; /* The Maintenance Point ID of this 'remote_mp'. */
102 struct hmap_node node
; /* Node in 'remote_mps' map. */
104 bool recv
; /* CCM was received since last fault check. */
105 bool rdi
; /* Remote Defect Indicator. Indicates remote_mp isn't
106 receiving CCMs that it's expecting to. */
109 static struct vlog_rate_limit rl
= VLOG_RATE_LIMIT_INIT(5, 20);
110 static struct hmap all_cfms
= HMAP_INITIALIZER(&all_cfms
);
112 static void cfm_unixctl_show(struct unixctl_conn
*, const char *args
,
115 static const uint8_t *
116 cfm_ccm_addr(const struct cfm
*cfm
)
118 return cfm
->extended
? eth_addr_ccm_x
: eth_addr_ccm
;
122 cfm_generate_maid(struct cfm
*cfm
)
124 const char *ovs_md_name
= "ovs";
125 const char *ovs_ma_name
= "ovs";
127 size_t md_len
, ma_len
;
129 memset(cfm
->maid
, 0, CCM_MAID_LEN
);
131 md_len
= strlen(ovs_md_name
);
132 ma_len
= strlen(ovs_ma_name
);
134 assert(md_len
&& ma_len
&& md_len
+ ma_len
+ 4 <= CCM_MAID_LEN
);
136 cfm
->maid
[0] = 4; /* MD name string format. */
137 cfm
->maid
[1] = md_len
; /* MD name size. */
138 memcpy(&cfm
->maid
[2], ovs_md_name
, md_len
); /* MD name. */
140 ma_p
= cfm
->maid
+ 2 + md_len
;
141 ma_p
[0] = 2; /* MA name string format. */
142 ma_p
[1] = ma_len
; /* MA name size. */
143 memcpy(&ma_p
[2], ovs_ma_name
, ma_len
); /* MA name. */
147 ccm_interval_to_ms(uint8_t interval
)
150 case 0: NOT_REACHED(); /* Explicitly not supported by 802.1ag. */
151 case 1: return 3; /* Not recommended due to timer resolution. */
152 case 2: return 10; /* Not recommended due to timer resolution. */
155 case 5: return 10000;
156 case 6: return 60000;
157 case 7: return 600000;
158 default: NOT_REACHED(); /* Explicitly not supported by 802.1ag. */
165 cfm_fault_interval(struct cfm
*cfm
)
167 /* According to the 802.1ag specification we should assume every other MP
168 * with the same MAID has the same transmission interval that we have. If
169 * an MP has a different interval, cfm_process_heartbeat will register it
170 * as a fault (likely due to a configuration error). Thus we can check all
171 * MPs at once making this quite a bit simpler.
173 * According to the specification we should check when (ccm_interval_ms *
174 * 3.5)ms have passed. */
175 return (cfm
->ccm_interval_ms
* 7) / 2;
179 ms_to_ccm_interval(int interval_ms
)
183 for (i
= 7; i
> 0; i
--) {
184 if (ccm_interval_to_ms(i
) <= interval_ms
) {
193 hash_mpid(uint64_t mpid
)
195 return hash_bytes(&mpid
, sizeof mpid
, 0);
199 cfm_is_valid_mpid(bool extended
, uint64_t mpid
)
201 /* 802.1ag specification requires MPIDs to be within the range [1, 8191].
202 * In extended mode we relax this requirement. */
203 return mpid
>= 1 && (extended
|| mpid
<= 8191);
206 static struct remote_mp
*
207 lookup_remote_mp(const struct cfm
*cfm
, uint64_t mpid
)
209 struct remote_mp
*rmp
;
211 HMAP_FOR_EACH_IN_BUCKET (rmp
, node
, hash_mpid(mpid
), &cfm
->remote_mps
) {
212 if (rmp
->mpid
== mpid
) {
223 unixctl_command_register("cfm/show", cfm_unixctl_show
, NULL
);
226 /* Allocates a 'cfm' object called 'name'. 'cfm' should be initialized by
227 * cfm_configure() before use. */
229 cfm_create(const char *name
)
233 cfm
= xzalloc(sizeof *cfm
);
234 cfm
->name
= xstrdup(name
);
235 hmap_init(&cfm
->remote_mps
);
236 cfm_generate_maid(cfm
);
237 hmap_insert(&all_cfms
, &cfm
->hmap_node
, hash_string(cfm
->name
, 0));
242 cfm_destroy(struct cfm
*cfm
)
244 struct remote_mp
*rmp
, *rmp_next
;
250 HMAP_FOR_EACH_SAFE (rmp
, rmp_next
, node
, &cfm
->remote_mps
) {
251 hmap_remove(&cfm
->remote_mps
, &rmp
->node
);
255 hmap_destroy(&cfm
->remote_mps
);
256 hmap_remove(&all_cfms
, &cfm
->hmap_node
);
257 free(cfm
->rmps_array
);
262 /* Should be run periodically to update fault statistics messages. */
264 cfm_run(struct cfm
*cfm
)
266 if (timer_expired(&cfm
->fault_timer
)) {
267 long long int interval
= cfm_fault_interval(cfm
);
268 struct remote_mp
*rmp
, *rmp_next
;
270 cfm
->fault
= cfm
->unexpected_recv
;
271 cfm
->unexpected_recv
= false;
273 cfm
->rmps_array_len
= 0;
274 free(cfm
->rmps_array
);
275 cfm
->rmps_array
= xmalloc(hmap_count(&cfm
->remote_mps
) *
276 sizeof *cfm
->rmps_array
);
278 HMAP_FOR_EACH_SAFE (rmp
, rmp_next
, node
, &cfm
->remote_mps
) {
281 VLOG_DBG("%s: no CCM from RMP %"PRIu64
" in the last %lldms",
282 cfm
->name
, rmp
->mpid
, interval
);
283 hmap_remove(&cfm
->remote_mps
, &rmp
->node
);
288 if (rmp
->mpid
== cfm
->mpid
) {
289 VLOG_WARN_RL(&rl
,"%s: received CCM with local MPID"
290 " %"PRIu64
, cfm
->name
, rmp
->mpid
);
295 VLOG_DBG("%s: RDI bit flagged from RMP %"PRIu64
, cfm
->name
,
300 cfm
->rmps_array
[cfm
->rmps_array_len
++] = rmp
->mpid
;
304 if (hmap_is_empty(&cfm
->remote_mps
)) {
308 timer_set_duration(&cfm
->fault_timer
, interval
);
312 /* Should be run periodically to check if the CFM module has a CCM message it
315 cfm_should_send_ccm(struct cfm
*cfm
)
317 return timer_expired(&cfm
->tx_timer
);
320 /* Composes a CCM message into 'packet'. Messages generated with this function
321 * should be sent whenever cfm_should_send_ccm() indicates. */
323 cfm_compose_ccm(struct cfm
*cfm
, struct ofpbuf
*packet
,
324 uint8_t eth_src
[ETH_ADDR_LEN
])
328 timer_set_duration(&cfm
->tx_timer
, cfm
->ccm_interval_ms
);
329 ccm
= eth_compose(packet
, cfm_ccm_addr(cfm
), eth_src
, ETH_TYPE_CFM
,
331 ccm
->mdlevel_version
= 0;
332 ccm
->opcode
= CCM_OPCODE
;
333 ccm
->tlv_offset
= 70;
334 ccm
->seq
= htonl(++cfm
->seq
);
335 ccm
->flags
= cfm
->ccm_interval
;
336 memcpy(ccm
->maid
, cfm
->maid
, sizeof ccm
->maid
);
337 memset(ccm
->zero
, 0, sizeof ccm
->zero
);
340 ccm
->mpid
= htons(hash_mpid(cfm
->mpid
));
341 ccm
->mpid64
= htonll(cfm
->mpid
);
343 ccm
->mpid
= htons(cfm
->mpid
);
344 ccm
->mpid64
= htonll(0);
347 if (cfm
->ccm_interval
== 0) {
348 assert(cfm
->extended
);
349 ccm
->interval_ms_x
= htons(cfm
->ccm_interval_ms
);
352 if (hmap_is_empty(&cfm
->remote_mps
)) {
353 ccm
->flags
|= CCM_RDI_MASK
;
358 cfm_wait(struct cfm
*cfm
)
361 timer_wait(&cfm
->tx_timer
);
362 timer_wait(&cfm
->fault_timer
);
365 /* Configures 'cfm' with settings from 's'. */
367 cfm_configure(struct cfm
*cfm
, const struct cfm_settings
*s
)
372 if (!cfm_is_valid_mpid(s
->extended
, s
->mpid
) || s
->interval
<= 0) {
377 cfm
->extended
= s
->extended
;
378 interval
= ms_to_ccm_interval(s
->interval
);
379 interval_ms
= ccm_interval_to_ms(interval
);
381 if (cfm
->extended
&& interval_ms
!= s
->interval
) {
383 interval_ms
= MIN(s
->interval
, UINT16_MAX
);
386 if (interval
!= cfm
->ccm_interval
|| interval_ms
!= cfm
->ccm_interval_ms
) {
387 cfm
->ccm_interval
= interval
;
388 cfm
->ccm_interval_ms
= interval_ms
;
390 timer_set_expired(&cfm
->tx_timer
);
391 timer_set_duration(&cfm
->fault_timer
, cfm_fault_interval(cfm
));
397 /* Returns true if 'cfm' should process packets from 'flow'. */
399 cfm_should_process_flow(const struct cfm
*cfm
, const struct flow
*flow
)
401 return (ntohs(flow
->dl_type
) == ETH_TYPE_CFM
402 && eth_addr_equals(flow
->dl_dst
, cfm_ccm_addr(cfm
)));
405 /* Updates internal statistics relevant to packet 'p'. Should be called on
406 * every packet whose flow returned true when passed to
407 * cfm_should_process_flow. */
409 cfm_process_heartbeat(struct cfm
*cfm
, const struct ofpbuf
*p
)
412 struct eth_header
*eth
;
415 ccm
= ofpbuf_at(p
, (uint8_t *)p
->l3
- (uint8_t *)p
->data
, CCM_LEN
);
418 VLOG_INFO_RL(&rl
, "%s: Received an unparseable 802.1ag CCM heartbeat.",
423 if (ccm
->opcode
!= CCM_OPCODE
) {
424 VLOG_INFO_RL(&rl
, "%s: Received an unsupported 802.1ag message. "
425 "(opcode %u)", cfm
->name
, ccm
->opcode
);
429 /* According to the 802.1ag specification, reception of a CCM with an
430 * incorrect ccm_interval, unexpected MAID, or unexpected MPID should
431 * trigger a fault. We ignore this requirement for several reasons.
433 * Faults can cause a controller or Open vSwitch to make potentially
434 * expensive changes to the network topology. It seems prudent to trigger
435 * them judiciously, especially when CFM is used to check slave status of
436 * bonds. Furthermore, faults can be maliciously triggered by crafting
438 if (memcmp(ccm
->maid
, cfm
->maid
, sizeof ccm
->maid
)) {
439 cfm
->unexpected_recv
= true;
440 VLOG_WARN_RL(&rl
, "%s: Received unexpected remote MAID from MAC "
441 ETH_ADDR_FMT
, cfm
->name
, ETH_ADDR_ARGS(eth
->eth_src
));
443 uint8_t ccm_interval
= ccm
->flags
& 0x7;
444 bool ccm_rdi
= ccm
->flags
& CCM_RDI_MASK
;
445 uint16_t ccm_interval_ms_x
= ntohs(ccm
->interval_ms_x
);
447 struct remote_mp
*rmp
;
450 ccm_mpid
= cfm
->extended
? ntohll(ccm
->mpid64
) : ntohs(ccm
->mpid
);
452 if (ccm_interval
!= cfm
->ccm_interval
) {
453 VLOG_WARN_RL(&rl
, "%s: received a CCM with an invalid interval"
454 " (%"PRIu8
") from RMP %"PRIu64
, cfm
->name
,
455 ccm_interval
, ccm_mpid
);
458 if (cfm
->extended
&& ccm_interval
== 0
459 && ccm_interval_ms_x
!= cfm
->ccm_interval_ms
) {
460 VLOG_WARN_RL(&rl
, "%s: received a CCM with an invalid extended"
461 " interval (%"PRIu16
"ms) from RMP %"PRIu64
, cfm
->name
,
462 ccm_interval_ms_x
, ccm_mpid
);
465 rmp
= lookup_remote_mp(cfm
, ccm_mpid
);
469 } else if (hmap_count(&cfm
->remote_mps
) < CFM_MAX_RMPS
) {
470 rmp
= xmalloc(sizeof *rmp
);
471 rmp
->mpid
= ccm_mpid
;
474 hmap_insert(&cfm
->remote_mps
, &rmp
->node
, hash_mpid(rmp
->mpid
));
476 cfm
->unexpected_recv
= true;
477 VLOG_WARN_RL(&rl
, "%s: dropped CCM with MPID %"PRIu64
" from MAC "
478 ETH_ADDR_FMT
, cfm
->name
, ccm_mpid
,
479 ETH_ADDR_ARGS(eth
->eth_src
));
482 VLOG_DBG("%s: received CCM (seq %"PRIu32
") (mpid %"PRIu64
")"
483 " (interval %"PRIu8
") (RDI %s)", cfm
->name
, ntohl(ccm
->seq
),
484 ccm_mpid
, ccm_interval
, ccm_rdi
? "true" : "false");
488 /* Gets the fault status of 'cfm'. Returns true when 'cfm' has detected
489 * connectivity problems, false otherwise. */
491 cfm_get_fault(const struct cfm
*cfm
)
496 /* Populates 'rmps' with an array of remote maintenance points reachable by
497 * 'cfm'. The number of remote maintenance points is written to 'n_rmps'.
498 * 'cfm' retains ownership of the array written to 'rmps' */
500 cfm_get_remote_mpids(const struct cfm
*cfm
, const uint64_t **rmps
,
503 *rmps
= cfm
->rmps_array
;
504 *n_rmps
= cfm
->rmps_array_len
;
508 cfm_find(const char *name
)
512 HMAP_FOR_EACH_WITH_HASH (cfm
, hmap_node
, hash_string(name
, 0), &all_cfms
) {
513 if (!strcmp(cfm
->name
, name
)) {
521 cfm_unixctl_show(struct unixctl_conn
*conn
,
522 const char *args
, void *aux OVS_UNUSED
)
524 struct ds ds
= DS_EMPTY_INITIALIZER
;
525 const struct cfm
*cfm
;
526 struct remote_mp
*rmp
;
528 cfm
= cfm_find(args
);
530 unixctl_command_reply(conn
, 501, "no such CFM object");
534 ds_put_format(&ds
, "MPID %"PRIu64
":%s%s\n", cfm
->mpid
,
535 cfm
->fault
? " fault" : "",
536 cfm
->unexpected_recv
? " unexpected_recv" : "");
538 ds_put_format(&ds
, "\tinterval: %dms\n", cfm
->ccm_interval_ms
);
539 ds_put_format(&ds
, "\tnext CCM tx: %lldms\n",
540 timer_msecs_until_expired(&cfm
->tx_timer
));
541 ds_put_format(&ds
, "\tnext fault check: %lldms\n",
542 timer_msecs_until_expired(&cfm
->fault_timer
));
544 ds_put_cstr(&ds
, "\n");
545 HMAP_FOR_EACH (rmp
, node
, &cfm
->remote_mps
) {
546 ds_put_format(&ds
, "Remote MPID %"PRIu64
":%s\n",
548 rmp
->rdi
? " rdi" : "");
549 ds_put_format(&ds
, "\trecv since check: %s",
550 rmp
->recv
? "true" : "false");
553 unixctl_command_reply(conn
, 200, ds_cstr(&ds
));