1 /* Copyright (c) 2013, 2014 Nicira, Inc.
3 * Licensed under the Apache License, Version 2.0 (the "License");
4 * you may not use this file except in compliance with the License.
5 * You may obtain a copy of the License at:
7 * http://www.apache.org/licenses/LICENSE-2.0
9 * Unless required by applicable law or agreed to in writing, software
10 * distributed under the License is distributed on an "AS IS" BASIS,
11 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12 * See the License for the specific language governing permissions and
13 * limitations under the License. */
18 #include <sys/types.h>
19 #include <arpa/inet.h>
20 #include <netinet/in_systm.h>
21 #include <netinet/ip.h>
22 #include <sys/socket.h>
24 #include "byte-order.h"
25 #include "connectivity.h"
28 #include "dynamic-string.h"
36 #include "ovs-thread.h"
37 #include "openvswitch/types.h"
39 #include "poll-loop.h"
44 #include "unaligned.h"
49 VLOG_DEFINE_THIS_MODULE(bfd);
53 * The goal of this module is to replace CFM with something both more flexible
54 * and standards compliant. In service of this goal, the following needs to be
58 * * Implement Demand mode.
59 * * Go through the RFC line by line and verify we comply.
60 * * Test against a hardware implementation. Preferably a popular one.
61 * * Delete BFD packets with nw_ttl != 255 in the datapath to prevent DOS
66 * - Set TOS/PCP on the outer tunnel header when encapped.
68 * - Sending BFD messages should be in its own thread/process.
70 * - Scale testing. How does it operate when there are large number of bfd
71 * sessions? Do we ever have random flaps? What's the CPU utilization?
73 * - Rely on data traffic for liveness by using BFD demand mode.
74 * If we're receiving traffic on a port, we can safely assume it's up (modulo
75 * unidrectional failures). BFD has a demand mode in which it can stay quiet
76 * unless it feels the need to check the status of the port. Using this, we
77 * can implement a strategy in which BFD only sends control messages on dark
80 * - Depending on how one interprets the spec, it appears that a BFD session
81 * can never change bfd.LocalDiag to "No Diagnostic". We should verify that
82 * this is what hardware implementations actually do. Seems like "No
83 * Diagnostic" should be set once a BFD session state goes UP. */
88 FLAG_MULTIPOINT = 1 << 0,
97 STATE_ADMIN_DOWN = 0 << 6,
104 DIAG_NONE = 0, /* No Diagnostic. */
105 DIAG_EXPIRED = 1, /* Control Detection Time Expired. */
106 DIAG_ECHO_FAILED = 2, /* Echo Function Failed. */
107 DIAG_RMT_DOWN = 3, /* Neighbor Signaled Session Down. */
108 DIAG_FWD_RESET = 4, /* Forwarding Plane Reset. */
109 DIAG_PATH_DOWN = 5, /* Path Down. */
110 DIAG_CPATH_DOWN = 6, /* Concatenated Path Down. */
111 DIAG_ADMIN_DOWN = 7, /* Administratively Down. */
112 DIAG_RCPATH_DOWN = 8 /* Reverse Concatenated Path Down. */
115 /* RFC 5880 Section 4.1
117 * 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
118 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
119 * |Vers | Diag |Sta|P|F|C|A|D|M| Detect Mult | Length |
120 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
121 * | My Discriminator |
122 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
123 * | Your Discriminator |
124 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
125 * | Desired Min TX Interval |
126 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
127 * | Required Min RX Interval |
128 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
129 * | Required Min Echo RX Interval |
130 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ */
132 uint8_t vers_diag; /* Version and diagnostic. */
133 uint8_t flags; /* 2bit State field followed by flags. */
134 uint8_t mult; /* Fault detection multiplier. */
135 uint8_t length; /* Length of this BFD message. */
136 ovs_be32 my_disc; /* My discriminator. */
137 ovs_be32 your_disc; /* Your discriminator. */
138 ovs_be32 min_tx; /* Desired minimum tx interval. */
139 ovs_be32 min_rx; /* Required minimum rx interval. */
140 ovs_be32 min_rx_echo; /* Required minimum echo rx interval. */
142 BUILD_ASSERT_DECL(BFD_PACKET_LEN == sizeof(struct msg));
144 #define DIAG_MASK 0x1f
146 #define STATE_MASK 0xC0
147 #define FLAGS_MASK 0x3f
150 struct hmap_node node; /* In 'all_bfds'. */
151 uint32_t disc; /* bfd.LocalDiscr. Key in 'all_bfds' hmap. */
153 char *name; /* Name used for logging. */
155 bool cpath_down; /* Concatenated Path Down. */
156 uint8_t mult; /* bfd.DetectMult. */
158 struct netdev *netdev;
159 uint64_t rx_packets; /* Packets received by 'netdev'. */
161 enum state state; /* bfd.SessionState. */
162 enum state rmt_state; /* bfd.RemoteSessionState. */
164 enum diag diag; /* bfd.LocalDiag. */
165 enum diag rmt_diag; /* Remote diagnostic. */
167 enum flags flags; /* Flags sent on messages. */
168 enum flags rmt_flags; /* Flags last received. */
170 uint32_t rmt_disc; /* bfd.RemoteDiscr. */
172 uint8_t local_eth_src[ETH_ADDR_LEN]; /* Local eth src address. */
173 uint8_t local_eth_dst[ETH_ADDR_LEN]; /* Local eth dst address. */
175 uint8_t rmt_eth_dst[ETH_ADDR_LEN]; /* Remote eth dst address. */
177 ovs_be32 ip_src; /* IPv4 source address. */
178 ovs_be32 ip_dst; /* IPv4 destination address. */
180 uint16_t udp_src; /* UDP source port. */
182 /* All timers in milliseconds. */
183 long long int rmt_min_rx; /* bfd.RemoteMinRxInterval. */
184 long long int rmt_min_tx; /* Remote minimum TX interval. */
186 long long int cfg_min_tx; /* Configured minimum TX rate. */
187 long long int cfg_min_rx; /* Configured required minimum RX rate. */
188 long long int poll_min_tx; /* Min TX negotating in a poll sequence. */
189 long long int poll_min_rx; /* Min RX negotating in a poll sequence. */
190 long long int min_tx; /* bfd.DesiredMinTxInterval. */
191 long long int min_rx; /* bfd.RequiredMinRxInterval. */
193 long long int last_tx; /* Last TX time. */
194 long long int next_tx; /* Next TX time. */
195 long long int detect_time; /* RFC 5880 6.8.4 Detection time. */
197 bool last_forwarding; /* Last calculation of forwarding flag. */
198 int forwarding_override; /* Manual override of 'forwarding' status. */
200 atomic_bool check_tnl_key; /* Verify tunnel key of inbound packets? */
201 struct ovs_refcount ref_cnt;
203 /* When forward_if_rx is true, bfd_forwarding() will return
204 * true as long as there are incoming packets received.
205 * Note, forwarding_override still has higher priority. */
206 bool forwarding_if_rx;
207 long long int forwarding_if_rx_detect_time;
209 /* When 'bfd->forwarding_if_rx' is set, at least one bfd control packet
210 * is required to be received every 100 * bfd->cfg_min_rx. If bfd
211 * control packet is not received within this interval, even if data
212 * packets are received, the bfd->forwarding will still be false. */
213 long long int demand_rx_bfd_time;
215 /* BFD decay related variables. */
216 bool in_decay; /* True when bfd is in decay. */
217 int decay_min_rx; /* min_rx is set to decay_min_rx when */
219 int decay_rx_ctl; /* Count bfd packets received within decay */
220 /* detect interval. */
221 uint64_t decay_rx_packets; /* Packets received by 'netdev'. */
222 long long int decay_detect_time; /* Decay detection time. */
224 uint64_t flap_count; /* Counts bfd forwarding flaps. */
226 /* True when the variables returned by bfd_get_status() are changed
227 * since last check. */
231 static struct ovs_mutex mutex = OVS_MUTEX_INITIALIZER;
232 static struct hmap all_bfds__ = HMAP_INITIALIZER(&all_bfds__);
233 static struct hmap *const all_bfds OVS_GUARDED_BY(mutex) = &all_bfds__;
235 static bool bfd_lookup_ip(const char *host_name, struct in_addr *)
237 static bool bfd_forwarding__(struct bfd *) OVS_REQUIRES(mutex);
238 static bool bfd_in_poll(const struct bfd *) OVS_REQUIRES(mutex);
239 static void bfd_poll(struct bfd *bfd) OVS_REQUIRES(mutex);
240 static const char *bfd_diag_str(enum diag) OVS_REQUIRES(mutex);
241 static const char *bfd_state_str(enum state) OVS_REQUIRES(mutex);
242 static long long int bfd_min_tx(const struct bfd *) OVS_REQUIRES(mutex);
243 static long long int bfd_tx_interval(const struct bfd *)
245 static long long int bfd_rx_interval(const struct bfd *)
247 static void bfd_set_next_tx(struct bfd *) OVS_REQUIRES(mutex);
248 static void bfd_set_state(struct bfd *, enum state, enum diag)
250 static uint32_t generate_discriminator(void) OVS_REQUIRES(mutex);
251 static void bfd_put_details(struct ds *, const struct bfd *)
253 static uint64_t bfd_rx_packets(const struct bfd *) OVS_REQUIRES(mutex);
254 static void bfd_try_decay(struct bfd *) OVS_REQUIRES(mutex);
255 static void bfd_decay_update(struct bfd *) OVS_REQUIRES(mutex);
256 static void bfd_status_changed(struct bfd *) OVS_REQUIRES(mutex);
258 static void bfd_forwarding_if_rx_update(struct bfd *) OVS_REQUIRES(mutex);
259 static void bfd_unixctl_show(struct unixctl_conn *, int argc,
260 const char *argv[], void *aux OVS_UNUSED);
261 static void bfd_unixctl_set_forwarding_override(struct unixctl_conn *,
262 int argc, const char *argv[],
263 void *aux OVS_UNUSED);
264 static void log_msg(enum vlog_level, const struct msg *, const char *message,
265 const struct bfd *) OVS_REQUIRES(mutex);
267 static struct vlog_rate_limit rl = VLOG_RATE_LIMIT_INIT(20, 20);
269 /* Returns true if the interface on which 'bfd' is running may be used to
270 * forward traffic according to the BFD session state. */
272 bfd_forwarding(struct bfd *bfd) OVS_EXCLUDED(mutex)
276 ovs_mutex_lock(&mutex);
277 ret = bfd_forwarding__(bfd);
278 ovs_mutex_unlock(&mutex);
282 /* When forwarding_if_rx is enabled, if there are packets received,
283 * updates forwarding_if_rx_detect_time. */
285 bfd_account_rx(struct bfd *bfd, const struct dpif_flow_stats *stats)
287 if (stats->n_packets && bfd->forwarding_if_rx) {
288 ovs_mutex_lock(&mutex);
289 bfd_forwarding__(bfd);
290 bfd_forwarding_if_rx_update(bfd);
291 bfd_forwarding__(bfd);
292 ovs_mutex_unlock(&mutex);
296 /* Returns and resets the 'bfd->status_changed'. */
298 bfd_check_status_change(struct bfd *bfd) OVS_EXCLUDED(mutex)
302 ovs_mutex_lock(&mutex);
303 ret = bfd->status_changed;
304 bfd->status_changed = false;
305 ovs_mutex_unlock(&mutex);
310 /* Returns a 'smap' of key value pairs representing the status of 'bfd'
311 * intended for the OVS database. */
313 bfd_get_status(const struct bfd *bfd, struct smap *smap)
316 ovs_mutex_lock(&mutex);
317 smap_add(smap, "forwarding",
318 bfd_forwarding__(CONST_CAST(struct bfd *, bfd))
320 smap_add(smap, "state", bfd_state_str(bfd->state));
321 smap_add(smap, "diagnostic", bfd_diag_str(bfd->diag));
322 smap_add_format(smap, "flap_count", "%"PRIu64, bfd->flap_count);
324 if (bfd->state != STATE_DOWN) {
325 smap_add(smap, "remote_state", bfd_state_str(bfd->rmt_state));
326 smap_add(smap, "remote_diagnostic", bfd_diag_str(bfd->rmt_diag));
328 ovs_mutex_unlock(&mutex);
331 /* Initializes, destroys, or reconfigures the BFD session 'bfd' (named 'name'),
332 * according to the database configuration contained in 'cfg'. Takes ownership
333 * of 'bfd', which may be NULL. Returns a BFD object which may be used as a
334 * handle for the session, or NULL if BFD is not enabled according to 'cfg'.
335 * Also returns NULL if cfg is NULL. */
337 bfd_configure(struct bfd *bfd, const char *name, const struct smap *cfg,
338 struct netdev *netdev) OVS_EXCLUDED(mutex)
340 static struct ovsthread_once once = OVSTHREAD_ONCE_INITIALIZER;
341 static atomic_uint16_t udp_src = ATOMIC_VAR_INIT(0);
344 long long int min_tx, min_rx;
345 bool need_poll = false;
346 bool cfg_min_rx_changed = false;
347 bool cpath_down, forwarding_if_rx;
348 const char *hwaddr, *ip_src, *ip_dst;
349 struct in_addr in_addr;
350 uint8_t ea[ETH_ADDR_LEN];
352 if (ovsthread_once_start(&once)) {
353 unixctl_command_register("bfd/show", "[interface]", 0, 1,
354 bfd_unixctl_show, NULL);
355 unixctl_command_register("bfd/set-forwarding",
356 "[interface] normal|false|true", 1, 2,
357 bfd_unixctl_set_forwarding_override, NULL);
358 ovsthread_once_done(&once);
361 if (!cfg || !smap_get_bool(cfg, "enable", false)) {
366 ovs_mutex_lock(&mutex);
368 bfd = xzalloc(sizeof *bfd);
369 bfd->name = xstrdup(name);
370 bfd->forwarding_override = -1;
371 bfd->disc = generate_discriminator();
372 hmap_insert(all_bfds, &bfd->node, bfd->disc);
374 bfd->diag = DIAG_NONE;
377 ovs_refcount_init(&bfd->ref_cnt);
378 bfd->netdev = netdev_ref(netdev);
379 bfd->rx_packets = bfd_rx_packets(bfd);
380 bfd->in_decay = false;
383 /* RFC 5881 section 4
384 * The source port MUST be in the range 49152 through 65535. The same
385 * UDP source port number MUST be used for all BFD Control packets
386 * associated with a particular session. The source port number SHOULD
387 * be unique among all BFD sessions on the system. */
388 atomic_add(&udp_src, 1, &bfd->udp_src);
389 bfd->udp_src = (bfd->udp_src % 16384) + 49152;
391 bfd_set_state(bfd, STATE_DOWN, DIAG_NONE);
393 bfd_status_changed(bfd);
396 atomic_store(&bfd->check_tnl_key,
397 smap_get_bool(cfg, "check_tnl_key", false));
398 min_tx = smap_get_int(cfg, "min_tx", 100);
399 min_tx = MAX(min_tx, 100);
400 if (bfd->cfg_min_tx != min_tx) {
401 bfd->cfg_min_tx = min_tx;
402 if (bfd->state != STATE_UP
403 || (!bfd_in_poll(bfd) && bfd->cfg_min_tx < bfd->min_tx)) {
404 bfd->min_tx = bfd->cfg_min_tx;
409 min_rx = smap_get_int(cfg, "min_rx", 1000);
410 min_rx = MAX(min_rx, 100);
411 if (bfd->cfg_min_rx != min_rx) {
412 bfd->cfg_min_rx = min_rx;
413 if (bfd->state != STATE_UP
414 || (!bfd_in_poll(bfd) && bfd->cfg_min_rx > bfd->min_rx)) {
415 bfd->min_rx = bfd->cfg_min_rx;
417 cfg_min_rx_changed = true;
421 decay_min_rx = smap_get_int(cfg, "decay_min_rx", 0);
422 if (bfd->decay_min_rx != decay_min_rx || cfg_min_rx_changed) {
423 if (decay_min_rx > 0 && decay_min_rx < bfd->cfg_min_rx) {
424 VLOG_WARN("%s: decay_min_rx cannot be less than %lld ms",
425 bfd->name, bfd->cfg_min_rx);
426 bfd->decay_min_rx = 0;
428 bfd->decay_min_rx = decay_min_rx;
431 bfd->in_decay = false;
432 bfd_decay_update(bfd);
436 cpath_down = smap_get_bool(cfg, "cpath_down", false);
437 if (bfd->cpath_down != cpath_down) {
438 bfd->cpath_down = cpath_down;
439 bfd_set_state(bfd, bfd->state, DIAG_NONE);
443 hwaddr = smap_get(cfg, "bfd_local_src_mac");
444 if (hwaddr && eth_addr_from_string(hwaddr, ea)) {
445 memcpy(bfd->local_eth_src, ea, ETH_ADDR_LEN);
447 memset(bfd->local_eth_src, 0, ETH_ADDR_LEN);
450 hwaddr = smap_get(cfg, "bfd_local_dst_mac");
451 if (hwaddr && eth_addr_from_string(hwaddr, ea)) {
452 memcpy(bfd->local_eth_dst, ea, ETH_ADDR_LEN);
454 memset(bfd->local_eth_dst, 0, ETH_ADDR_LEN);
457 hwaddr = smap_get(cfg, "bfd_remote_dst_mac");
458 if (hwaddr && eth_addr_from_string(hwaddr, ea)) {
459 memcpy(bfd->rmt_eth_dst, ea, ETH_ADDR_LEN);
461 memset(bfd->rmt_eth_dst, 0, ETH_ADDR_LEN);
464 ip_src = smap_get(cfg, "bfd_src_ip");
465 if (ip_src && bfd_lookup_ip(ip_src, &in_addr)) {
466 memcpy(&bfd->ip_src, &in_addr, sizeof in_addr);
468 bfd->ip_src = htonl(0xA9FE0101); /* 169.254.1.1. */
471 ip_dst = smap_get(cfg, "bfd_dst_ip");
472 if (ip_dst && bfd_lookup_ip(ip_dst, &in_addr)) {
473 memcpy(&bfd->ip_dst, &in_addr, sizeof in_addr);
475 bfd->ip_dst = htonl(0xA9FE0100); /* 169.254.1.0. */
478 forwarding_if_rx = smap_get_bool(cfg, "forwarding_if_rx", false);
479 if (bfd->forwarding_if_rx != forwarding_if_rx) {
480 bfd->forwarding_if_rx = forwarding_if_rx;
481 if (bfd->state == STATE_UP && bfd->forwarding_if_rx) {
482 bfd_forwarding_if_rx_update(bfd);
484 bfd->forwarding_if_rx_detect_time = 0;
491 ovs_mutex_unlock(&mutex);
496 bfd_ref(const struct bfd *bfd_)
498 struct bfd *bfd = CONST_CAST(struct bfd *, bfd_);
500 ovs_refcount_ref(&bfd->ref_cnt);
506 bfd_unref(struct bfd *bfd) OVS_EXCLUDED(mutex)
508 if (bfd && ovs_refcount_unref(&bfd->ref_cnt) == 1) {
509 ovs_mutex_lock(&mutex);
510 bfd_status_changed(bfd);
511 hmap_remove(all_bfds, &bfd->node);
512 netdev_close(bfd->netdev);
515 ovs_mutex_unlock(&mutex);
520 bfd_wait(const struct bfd *bfd) OVS_EXCLUDED(mutex)
522 poll_timer_wait_until(bfd_wake_time(bfd));
525 /* Returns the next wake up time. */
527 bfd_wake_time(const struct bfd *bfd) OVS_EXCLUDED(mutex)
529 long long int retval;
535 ovs_mutex_lock(&mutex);
536 if (bfd->flags & FLAG_FINAL) {
539 retval = bfd->next_tx;
540 if (bfd->state > STATE_DOWN) {
541 retval = MIN(bfd->detect_time, retval);
544 ovs_mutex_unlock(&mutex);
549 bfd_run(struct bfd *bfd) OVS_EXCLUDED(mutex)
554 ovs_mutex_lock(&mutex);
556 old_in_decay = bfd->in_decay;
558 if (bfd->state > STATE_DOWN && now >= bfd->detect_time) {
559 bfd_set_state(bfd, STATE_DOWN, DIAG_EXPIRED);
561 bfd_forwarding__(bfd);
563 /* Decay may only happen when state is STATE_UP, bfd->decay_min_rx is
564 * configured, and decay_detect_time is reached. */
565 if (bfd->state == STATE_UP && bfd->decay_min_rx > 0
566 && now >= bfd->decay_detect_time) {
570 if (bfd->min_tx != bfd->cfg_min_tx
571 || (bfd->min_rx != bfd->cfg_min_rx && bfd->min_rx != bfd->decay_min_rx)
572 || bfd->in_decay != old_in_decay) {
575 ovs_mutex_unlock(&mutex);
579 bfd_should_send_packet(const struct bfd *bfd) OVS_EXCLUDED(mutex)
582 ovs_mutex_lock(&mutex);
583 ret = bfd->flags & FLAG_FINAL || time_msec() >= bfd->next_tx;
584 ovs_mutex_unlock(&mutex);
589 bfd_put_packet(struct bfd *bfd, struct ofpbuf *p,
590 uint8_t eth_src[ETH_ADDR_LEN]) OVS_EXCLUDED(mutex)
592 long long int min_tx, min_rx;
593 struct udp_header *udp;
594 struct eth_header *eth;
595 struct ip_header *ip;
598 ovs_mutex_lock(&mutex);
600 long long int delay = time_msec() - bfd->next_tx;
601 long long int interval = bfd_tx_interval(bfd);
602 if (delay > interval * 3 / 2) {
603 VLOG_INFO("%s: long delay of %lldms (expected %lldms) sending BFD"
604 " control message", bfd->name, delay, interval);
608 /* RFC 5880 Section 6.5
609 * A BFD Control packet MUST NOT have both the Poll (P) and Final (F) bits
611 ovs_assert(!(bfd->flags & FLAG_POLL) || !(bfd->flags & FLAG_FINAL));
613 ofpbuf_reserve(p, 2); /* Properly align after the ethernet header. */
614 eth = ofpbuf_put_uninit(p, sizeof *eth);
616 eth_addr_is_zero(bfd->local_eth_src) ? eth_src
617 : bfd->local_eth_src,
620 eth_addr_is_zero(bfd->local_eth_dst) ? eth_addr_bfd
621 : bfd->local_eth_dst,
623 eth->eth_type = htons(ETH_TYPE_IP);
625 ip = ofpbuf_put_zeros(p, sizeof *ip);
626 ip->ip_ihl_ver = IP_IHL_VER(5, 4);
627 ip->ip_tot_len = htons(sizeof *ip + sizeof *udp + sizeof *msg);
629 ip->ip_tos = IPTOS_LOWDELAY | IPTOS_THROUGHPUT;
630 ip->ip_proto = IPPROTO_UDP;
631 put_16aligned_be32(&ip->ip_src, bfd->ip_src);
632 put_16aligned_be32(&ip->ip_dst, bfd->ip_dst);
633 ip->ip_csum = csum(ip, sizeof *ip);
635 udp = ofpbuf_put_zeros(p, sizeof *udp);
636 udp->udp_src = htons(bfd->udp_src);
637 udp->udp_dst = htons(BFD_DEST_PORT);
638 udp->udp_len = htons(sizeof *udp + sizeof *msg);
640 msg = ofpbuf_put_uninit(p, sizeof *msg);
641 msg->vers_diag = (BFD_VERSION << 5) | bfd->diag;
642 msg->flags = (bfd->state & STATE_MASK) | bfd->flags;
644 msg->mult = bfd->mult;
645 msg->length = BFD_PACKET_LEN;
646 msg->my_disc = htonl(bfd->disc);
647 msg->your_disc = htonl(bfd->rmt_disc);
648 msg->min_rx_echo = htonl(0);
650 if (bfd_in_poll(bfd)) {
651 min_tx = bfd->poll_min_tx;
652 min_rx = bfd->poll_min_rx;
654 min_tx = bfd_min_tx(bfd);
655 min_rx = bfd->min_rx;
658 msg->min_tx = htonl(min_tx * 1000);
659 msg->min_rx = htonl(min_rx * 1000);
661 bfd->flags &= ~FLAG_FINAL;
663 log_msg(VLL_DBG, msg, "Sending BFD Message", bfd);
665 bfd->last_tx = time_msec();
666 bfd_set_next_tx(bfd);
667 ovs_mutex_unlock(&mutex);
671 bfd_should_process_flow(const struct bfd *bfd_, const struct flow *flow,
672 struct flow_wildcards *wc)
674 struct bfd *bfd = CONST_CAST(struct bfd *, bfd_);
677 memset(&wc->masks.dl_dst, 0xff, sizeof wc->masks.dl_dst);
678 if (!eth_addr_is_zero(bfd->rmt_eth_dst)
679 && memcmp(bfd->rmt_eth_dst, flow->dl_dst, ETH_ADDR_LEN)) {
683 memset(&wc->masks.nw_proto, 0xff, sizeof wc->masks.nw_proto);
684 memset(&wc->masks.tp_dst, 0xff, sizeof wc->masks.tp_dst);
686 atomic_read(&bfd->check_tnl_key, &check_tnl_key);
688 memset(&wc->masks.tunnel.tun_id, 0xff, sizeof wc->masks.tunnel.tun_id);
690 return (flow->dl_type == htons(ETH_TYPE_IP)
691 && flow->nw_proto == IPPROTO_UDP
692 && flow->tp_dst == htons(BFD_DEST_PORT)
693 && (!check_tnl_key || flow->tunnel.tun_id == htonll(0)));
697 bfd_process_packet(struct bfd *bfd, const struct flow *flow,
698 const struct ofpbuf *p) OVS_EXCLUDED(mutex)
700 uint32_t rmt_min_rx, pkt_your_disc;
701 enum state rmt_state;
705 const uint8_t *l7 = ofpbuf_get_udp_payload(p);
708 return; /* No UDP payload. */
711 /* This function is designed to follow section RFC 5880 6.8.6 closely. */
713 ovs_mutex_lock(&mutex);
714 /* Increments the decay rx counter. */
717 bfd_forwarding__(bfd);
719 if (flow->nw_ttl != 255) {
720 /* XXX Should drop in the kernel to prevent DOS. */
724 msg = ofpbuf_at(p, l7 - (uint8_t *)ofpbuf_data(p), BFD_PACKET_LEN);
726 VLOG_INFO_RL(&rl, "%s: Received too-short BFD control message (only "
727 "%"PRIdPTR" bytes long, at least %d required).",
728 bfd->name, (uint8_t *) ofpbuf_tail(p) - l7,
733 /* RFC 5880 Section 6.8.6
734 * If the Length field is greater than the payload of the encapsulating
735 * protocol, the packet MUST be discarded.
737 * Note that we make this check implicity. Above we use ofpbuf_at() to
738 * ensure that there are at least BFD_PACKET_LEN bytes in the payload of
739 * the encapsulating protocol. Below we require msg->length to be exactly
740 * BFD_PACKET_LEN bytes. */
742 flags = msg->flags & FLAGS_MASK;
743 rmt_state = msg->flags & STATE_MASK;
744 version = msg->vers_diag >> VERS_SHIFT;
746 log_msg(VLL_DBG, msg, "Received BFD control message", bfd);
748 if (version != BFD_VERSION) {
749 log_msg(VLL_WARN, msg, "Incorrect version", bfd);
753 /* Technically this should happen after the length check. We don't support
754 * authentication however, so it's simpler to do the check first. */
755 if (flags & FLAG_AUTH) {
756 log_msg(VLL_WARN, msg, "Authenticated control message with"
757 " authentication disabled", bfd);
761 if (msg->length != BFD_PACKET_LEN) {
762 log_msg(VLL_WARN, msg, "Unexpected length", bfd);
763 if (msg->length < BFD_PACKET_LEN) {
769 log_msg(VLL_WARN, msg, "Zero multiplier", bfd);
773 if (flags & FLAG_MULTIPOINT) {
774 log_msg(VLL_WARN, msg, "Unsupported multipoint flag", bfd);
779 log_msg(VLL_WARN, msg, "NULL my_disc", bfd);
783 pkt_your_disc = ntohl(msg->your_disc);
785 /* Technically, we should use the your discriminator field to figure
786 * out which 'struct bfd' this packet is destined towards. That way a
787 * bfd session could migrate from one interface to another
788 * transparently. This doesn't fit in with the OVS structure very
789 * well, so in this respect, we are not compliant. */
790 if (pkt_your_disc != bfd->disc) {
791 log_msg(VLL_WARN, msg, "Incorrect your_disc", bfd);
794 } else if (rmt_state > STATE_DOWN) {
795 log_msg(VLL_WARN, msg, "Null your_disc", bfd);
799 if (bfd->rmt_state != rmt_state) {
800 bfd_status_changed(bfd);
803 bfd->rmt_disc = ntohl(msg->my_disc);
804 bfd->rmt_state = rmt_state;
805 bfd->rmt_flags = flags;
806 bfd->rmt_diag = msg->vers_diag & DIAG_MASK;
808 if (flags & FLAG_FINAL && bfd_in_poll(bfd)) {
809 bfd->min_tx = bfd->poll_min_tx;
810 bfd->min_rx = bfd->poll_min_rx;
811 bfd->flags &= ~FLAG_POLL;
812 log_msg(VLL_INFO, msg, "Poll sequence terminated", bfd);
815 if (flags & FLAG_POLL) {
816 /* RFC 5880 Section 6.5
817 * When the other system receives a Poll, it immediately transmits a
818 * BFD Control packet with the Final (F) bit set, independent of any
819 * periodic BFD Control packets it may be sending
820 * (see section 6.8.7). */
821 bfd->flags &= ~FLAG_POLL;
822 bfd->flags |= FLAG_FINAL;
825 rmt_min_rx = MAX(ntohl(msg->min_rx) / 1000, 1);
826 if (bfd->rmt_min_rx != rmt_min_rx) {
827 bfd->rmt_min_rx = rmt_min_rx;
829 bfd_set_next_tx(bfd);
831 log_msg(VLL_INFO, msg, "New remote min_rx", bfd);
834 bfd->rmt_min_tx = MAX(ntohl(msg->min_tx) / 1000, 1);
835 bfd->detect_time = bfd_rx_interval(bfd) * bfd->mult + time_msec();
837 if (bfd->state == STATE_ADMIN_DOWN) {
838 VLOG_DBG_RL(&rl, "Administratively down, dropping control message.");
842 if (rmt_state == STATE_ADMIN_DOWN) {
843 if (bfd->state != STATE_DOWN) {
844 bfd_set_state(bfd, STATE_DOWN, DIAG_RMT_DOWN);
847 switch (bfd->state) {
849 if (rmt_state == STATE_DOWN) {
850 bfd_set_state(bfd, STATE_INIT, bfd->diag);
851 } else if (rmt_state == STATE_INIT) {
852 bfd_set_state(bfd, STATE_UP, bfd->diag);
856 if (rmt_state > STATE_DOWN) {
857 bfd_set_state(bfd, STATE_UP, bfd->diag);
861 if (rmt_state <= STATE_DOWN) {
862 bfd_set_state(bfd, STATE_DOWN, DIAG_RMT_DOWN);
863 log_msg(VLL_INFO, msg, "Remote signaled STATE_DOWN", bfd);
866 case STATE_ADMIN_DOWN:
871 /* XXX: RFC 5880 Section 6.8.6 Demand mode related calculations here. */
873 if (bfd->forwarding_if_rx) {
874 bfd->demand_rx_bfd_time = time_msec() + 100 * bfd->cfg_min_rx;
878 bfd_forwarding__(bfd);
879 ovs_mutex_unlock(&mutex);
882 /* Must be called when the netdev owned by 'bfd' should change. */
884 bfd_set_netdev(struct bfd *bfd, const struct netdev *netdev)
887 ovs_mutex_lock(&mutex);
888 if (bfd->netdev != netdev) {
889 netdev_close(bfd->netdev);
890 bfd->netdev = netdev_ref(netdev);
891 if (bfd->decay_min_rx && bfd->state == STATE_UP) {
892 bfd_decay_update(bfd);
894 if (bfd->forwarding_if_rx && bfd->state == STATE_UP) {
895 bfd_forwarding_if_rx_update(bfd);
897 bfd->rx_packets = bfd_rx_packets(bfd);
899 ovs_mutex_unlock(&mutex);
903 /* Updates the forwarding flag. If override is not configured and
904 * the forwarding flag value changes, increments the flap count.
906 * Note this function may be called multiple times in a function
907 * (e.g. bfd_account_rx) before and after the bfd state or status
908 * change. This is to capture any forwarding flag flap. */
910 bfd_forwarding__(struct bfd *bfd) OVS_REQUIRES(mutex)
912 long long int now = time_msec();
913 bool forwarding_if_rx;
914 bool last_forwarding = bfd->last_forwarding;
916 if (bfd->forwarding_override != -1) {
917 return bfd->forwarding_override == 1;
920 forwarding_if_rx = bfd->forwarding_if_rx
921 && bfd->forwarding_if_rx_detect_time > now
922 && bfd->demand_rx_bfd_time > now;
924 bfd->last_forwarding = (bfd->state == STATE_UP || forwarding_if_rx)
925 && bfd->rmt_diag != DIAG_PATH_DOWN
926 && bfd->rmt_diag != DIAG_CPATH_DOWN
927 && bfd->rmt_diag != DIAG_RCPATH_DOWN;
928 if (bfd->last_forwarding != last_forwarding) {
930 bfd_status_changed(bfd);
932 return bfd->last_forwarding;
937 bfd_lookup_ip(const char *host_name, struct in_addr *addr)
939 if (!inet_pton(AF_INET, host_name, addr)) {
940 VLOG_ERR_RL(&rl, "\"%s\" is not a valid IP address", host_name);
947 bfd_in_poll(const struct bfd *bfd) OVS_REQUIRES(mutex)
949 return (bfd->flags & FLAG_POLL) != 0;
953 bfd_poll(struct bfd *bfd) OVS_REQUIRES(mutex)
955 if (bfd->state > STATE_DOWN && !bfd_in_poll(bfd)
956 && !(bfd->flags & FLAG_FINAL)) {
957 bfd->poll_min_tx = bfd->cfg_min_tx;
958 bfd->poll_min_rx = bfd->in_decay ? bfd->decay_min_rx : bfd->cfg_min_rx;
959 bfd->flags |= FLAG_POLL;
961 VLOG_INFO_RL(&rl, "%s: Initiating poll sequence", bfd->name);
966 bfd_min_tx(const struct bfd *bfd) OVS_REQUIRES(mutex)
968 /* RFC 5880 Section 6.8.3
969 * When bfd.SessionState is not Up, the system MUST set
970 * bfd.DesiredMinTxInterval to a value of not less than one second
971 * (1,000,000 microseconds). This is intended to ensure that the
972 * bandwidth consumed by BFD sessions that are not Up is negligible,
973 * particularly in the case where a neighbor may not be running BFD. */
974 return (bfd->state == STATE_UP ? bfd->min_tx : MAX(bfd->min_tx, 1000));
978 bfd_tx_interval(const struct bfd *bfd) OVS_REQUIRES(mutex)
980 long long int interval = bfd_min_tx(bfd);
981 return MAX(interval, bfd->rmt_min_rx);
985 bfd_rx_interval(const struct bfd *bfd) OVS_REQUIRES(mutex)
987 return MAX(bfd->min_rx, bfd->rmt_min_tx);
991 bfd_set_next_tx(struct bfd *bfd) OVS_REQUIRES(mutex)
993 long long int interval = bfd_tx_interval(bfd);
994 interval -= interval * random_range(26) / 100;
995 bfd->next_tx = bfd->last_tx + interval;
999 bfd_flag_str(enum flags flags)
1001 struct ds ds = DS_EMPTY_INITIALIZER;
1002 static char flag_str[128];
1008 if (flags & FLAG_MULTIPOINT) {
1009 ds_put_cstr(&ds, "multipoint ");
1012 if (flags & FLAG_DEMAND) {
1013 ds_put_cstr(&ds, "demand ");
1016 if (flags & FLAG_AUTH) {
1017 ds_put_cstr(&ds, "auth ");
1020 if (flags & FLAG_CTL) {
1021 ds_put_cstr(&ds, "ctl ");
1024 if (flags & FLAG_FINAL) {
1025 ds_put_cstr(&ds, "final ");
1028 if (flags & FLAG_POLL) {
1029 ds_put_cstr(&ds, "poll ");
1032 /* Do not copy the trailing whitespace. */
1034 ovs_strlcpy(flag_str, ds_cstr(&ds), sizeof flag_str);
1040 bfd_state_str(enum state state)
1043 case STATE_ADMIN_DOWN: return "admin_down";
1044 case STATE_DOWN: return "down";
1045 case STATE_INIT: return "init";
1046 case STATE_UP: return "up";
1047 default: return "invalid";
1052 bfd_diag_str(enum diag diag) {
1054 case DIAG_NONE: return "No Diagnostic";
1055 case DIAG_EXPIRED: return "Control Detection Time Expired";
1056 case DIAG_ECHO_FAILED: return "Echo Function Failed";
1057 case DIAG_RMT_DOWN: return "Neighbor Signaled Session Down";
1058 case DIAG_FWD_RESET: return "Forwarding Plane Reset";
1059 case DIAG_PATH_DOWN: return "Path Down";
1060 case DIAG_CPATH_DOWN: return "Concatenated Path Down";
1061 case DIAG_ADMIN_DOWN: return "Administratively Down";
1062 case DIAG_RCPATH_DOWN: return "Reverse Concatenated Path Down";
1063 default: return "Invalid Diagnostic";
1068 log_msg(enum vlog_level level, const struct msg *p, const char *message,
1069 const struct bfd *bfd) OVS_REQUIRES(mutex)
1071 struct ds ds = DS_EMPTY_INITIALIZER;
1073 if (vlog_should_drop(THIS_MODULE, level, &rl)) {
1079 "\n\tvers:%"PRIu8" diag:\"%s\" state:%s mult:%"PRIu8
1082 "\n\tmy_disc:0x%"PRIx32" your_disc:0x%"PRIx32
1083 "\n\tmin_tx:%"PRIu32"us (%"PRIu32"ms)"
1084 "\n\tmin_rx:%"PRIu32"us (%"PRIu32"ms)"
1085 "\n\tmin_rx_echo:%"PRIu32"us (%"PRIu32"ms)",
1086 bfd->name, message, p->vers_diag >> VERS_SHIFT,
1087 bfd_diag_str(p->vers_diag & DIAG_MASK),
1088 bfd_state_str(p->flags & STATE_MASK),
1089 p->mult, p->length, bfd_flag_str(p->flags & FLAGS_MASK),
1090 ntohl(p->my_disc), ntohl(p->your_disc),
1091 ntohl(p->min_tx), ntohl(p->min_tx) / 1000,
1092 ntohl(p->min_rx), ntohl(p->min_rx) / 1000,
1093 ntohl(p->min_rx_echo), ntohl(p->min_rx_echo) / 1000);
1094 bfd_put_details(&ds, bfd);
1095 VLOG(level, "%s", ds_cstr(&ds));
1100 bfd_set_state(struct bfd *bfd, enum state state, enum diag diag)
1103 if (bfd->cpath_down) {
1104 diag = DIAG_CPATH_DOWN;
1107 if (bfd->state != state || bfd->diag != diag) {
1108 if (!VLOG_DROP_INFO(&rl)) {
1109 struct ds ds = DS_EMPTY_INITIALIZER;
1111 ds_put_format(&ds, "%s: BFD state change: %s->%s"
1112 " \"%s\"->\"%s\".\n",
1113 bfd->name, bfd_state_str(bfd->state),
1114 bfd_state_str(state), bfd_diag_str(bfd->diag),
1115 bfd_diag_str(diag));
1116 bfd_put_details(&ds, bfd);
1117 VLOG_INFO("%s", ds_cstr(&ds));
1124 if (bfd->state <= STATE_DOWN) {
1125 bfd->rmt_state = STATE_DOWN;
1126 bfd->rmt_diag = DIAG_NONE;
1127 bfd->rmt_min_rx = 1;
1130 bfd->rmt_min_tx = 0;
1131 /* Resets the min_rx if in_decay. */
1132 if (bfd->in_decay) {
1133 bfd->min_rx = bfd->cfg_min_rx;
1134 bfd->in_decay = false;
1137 /* Resets the decay when state changes to STATE_UP
1138 * and decay_min_rx is configured. */
1139 if (bfd->state == STATE_UP && bfd->decay_min_rx) {
1140 bfd_decay_update(bfd);
1143 bfd_status_changed(bfd);
1148 bfd_rx_packets(const struct bfd *bfd) OVS_REQUIRES(mutex)
1150 struct netdev_stats stats;
1152 if (!netdev_get_stats(bfd->netdev, &stats)) {
1153 return stats.rx_packets;
1159 /* Decays the bfd->min_rx to bfd->decay_min_rx when 'diff' is less than
1160 * the 'expect' value. */
1162 bfd_try_decay(struct bfd *bfd) OVS_REQUIRES(mutex)
1164 int64_t diff, expect;
1166 /* The 'diff' is the difference between current interface rx_packets
1167 * stats and last-time check. The 'expect' is the recorded number of
1168 * bfd control packets received within an approximately decay_min_rx
1169 * (2000 ms if decay_min_rx is less than 2000 ms) interval.
1171 * Since the update of rx_packets stats at interface happens
1172 * asynchronously to the bfd_rx_packets() function, the 'diff' value
1173 * can be jittered. Thusly, we double the decay_rx_ctl to provide
1174 * more wiggle room. */
1175 diff = bfd_rx_packets(bfd) - bfd->decay_rx_packets;
1176 expect = 2 * MAX(bfd->decay_rx_ctl, 1);
1177 bfd->in_decay = diff <= expect ? true : false;
1178 bfd_decay_update(bfd);
1181 /* Updates the rx_packets, decay_rx_ctl and decay_detect_time. */
1183 bfd_decay_update(struct bfd * bfd) OVS_REQUIRES(mutex)
1185 bfd->decay_rx_packets = bfd_rx_packets(bfd);
1186 bfd->decay_rx_ctl = 0;
1187 bfd->decay_detect_time = MAX(bfd->decay_min_rx, 2000) + time_msec();
1190 /* Records the status change and changes the global connectivity seq. */
1192 bfd_status_changed(struct bfd *bfd) OVS_REQUIRES(mutex)
1194 seq_change(connectivity_seq_get());
1195 bfd->status_changed = true;
1199 bfd_forwarding_if_rx_update(struct bfd *bfd) OVS_REQUIRES(mutex)
1201 int64_t incr = bfd_rx_interval(bfd) * bfd->mult;
1202 bfd->forwarding_if_rx_detect_time = MAX(incr, 2000) + time_msec();
1206 generate_discriminator(void)
1210 /* RFC 5880 Section 6.8.1
1211 * It SHOULD be set to a random (but still unique) value to improve
1212 * security. The value is otherwise outside the scope of this
1218 /* 'disc' is by definition random, so there's no reason to waste time
1220 disc = random_uint32();
1221 HMAP_FOR_EACH_IN_BUCKET (bfd, node, disc, all_bfds) {
1222 if (bfd->disc == disc) {
1233 bfd_find_by_name(const char *name) OVS_REQUIRES(mutex)
1237 HMAP_FOR_EACH (bfd, node, all_bfds) {
1238 if (!strcmp(bfd->name, name)) {
1246 bfd_put_details(struct ds *ds, const struct bfd *bfd) OVS_REQUIRES(mutex)
1248 ds_put_format(ds, "\tForwarding: %s\n",
1249 bfd_forwarding__(CONST_CAST(struct bfd *, bfd))
1250 ? "true" : "false");
1251 ds_put_format(ds, "\tDetect Multiplier: %d\n", bfd->mult);
1252 ds_put_format(ds, "\tConcatenated Path Down: %s\n",
1253 bfd->cpath_down ? "true" : "false");
1254 ds_put_format(ds, "\tTX Interval: Approx %lldms\n", bfd_tx_interval(bfd));
1255 ds_put_format(ds, "\tRX Interval: Approx %lldms\n", bfd_rx_interval(bfd));
1256 ds_put_format(ds, "\tDetect Time: now %+lldms\n",
1257 time_msec() - bfd->detect_time);
1258 ds_put_format(ds, "\tNext TX Time: now %+lldms\n",
1259 time_msec() - bfd->next_tx);
1260 ds_put_format(ds, "\tLast TX Time: now %+lldms\n",
1261 time_msec() - bfd->last_tx);
1263 ds_put_cstr(ds, "\n");
1265 ds_put_format(ds, "\tLocal Flags: %s\n", bfd_flag_str(bfd->flags));
1266 ds_put_format(ds, "\tLocal Session State: %s\n",
1267 bfd_state_str(bfd->state));
1268 ds_put_format(ds, "\tLocal Diagnostic: %s\n", bfd_diag_str(bfd->diag));
1269 ds_put_format(ds, "\tLocal Discriminator: 0x%"PRIx32"\n", bfd->disc);
1270 ds_put_format(ds, "\tLocal Minimum TX Interval: %lldms\n",
1272 ds_put_format(ds, "\tLocal Minimum RX Interval: %lldms\n", bfd->min_rx);
1274 ds_put_cstr(ds, "\n");
1276 ds_put_format(ds, "\tRemote Flags: %s\n", bfd_flag_str(bfd->rmt_flags));
1277 ds_put_format(ds, "\tRemote Session State: %s\n",
1278 bfd_state_str(bfd->rmt_state));
1279 ds_put_format(ds, "\tRemote Diagnostic: %s\n",
1280 bfd_diag_str(bfd->rmt_diag));
1281 ds_put_format(ds, "\tRemote Discriminator: 0x%"PRIx32"\n", bfd->rmt_disc);
1282 ds_put_format(ds, "\tRemote Minimum TX Interval: %lldms\n",
1284 ds_put_format(ds, "\tRemote Minimum RX Interval: %lldms\n",
1289 bfd_unixctl_show(struct unixctl_conn *conn, int argc, const char *argv[],
1290 void *aux OVS_UNUSED) OVS_EXCLUDED(mutex)
1292 struct ds ds = DS_EMPTY_INITIALIZER;
1295 ovs_mutex_lock(&mutex);
1297 bfd = bfd_find_by_name(argv[1]);
1299 unixctl_command_reply_error(conn, "no such bfd object");
1302 bfd_put_details(&ds, bfd);
1304 HMAP_FOR_EACH (bfd, node, all_bfds) {
1305 ds_put_format(&ds, "---- %s ----\n", bfd->name);
1306 bfd_put_details(&ds, bfd);
1309 unixctl_command_reply(conn, ds_cstr(&ds));
1313 ovs_mutex_unlock(&mutex);
1318 bfd_unixctl_set_forwarding_override(struct unixctl_conn *conn, int argc,
1319 const char *argv[], void *aux OVS_UNUSED)
1322 const char *forward_str = argv[argc - 1];
1323 int forwarding_override;
1326 ovs_mutex_lock(&mutex);
1327 if (!strcasecmp("true", forward_str)) {
1328 forwarding_override = 1;
1329 } else if (!strcasecmp("false", forward_str)) {
1330 forwarding_override = 0;
1331 } else if (!strcasecmp("normal", forward_str)) {
1332 forwarding_override = -1;
1334 unixctl_command_reply_error(conn, "unknown fault string");
1339 bfd = bfd_find_by_name(argv[1]);
1341 unixctl_command_reply_error(conn, "no such BFD object");
1344 bfd->forwarding_override = forwarding_override;
1345 bfd_status_changed(bfd);
1347 HMAP_FOR_EACH (bfd, node, all_bfds) {
1348 bfd->forwarding_override = forwarding_override;
1349 bfd_status_changed(bfd);
1353 unixctl_command_reply(conn, "OK");
1356 ovs_mutex_unlock(&mutex);