1: /*
2: * BIRD -- Bidirectional Forwarding Detection (BFD)
3: *
4: * Can be freely distributed and used under the terms of the GNU GPL.
5: */
6:
7: /**
8: * DOC: Bidirectional Forwarding Detection
9: *
10: * The BFD protocol is implemented in three files: |bfd.c| containing the
11: * protocol logic and the protocol glue with BIRD core, |packets.c| handling BFD
12: * packet processing, RX, TX and protocol sockets. |io.c| then contains generic
13: * code for the event loop, threads and event sources (sockets, microsecond
14: * timers). This generic code will be merged to the main BIRD I/O code in the
15: * future.
16: *
17: * The BFD implementation uses a separate thread with an internal event loop for
18: * handling the protocol logic, which requires high-res and low-latency timing,
19: * so it is not affected by the rest of BIRD, which has several low-granularity
20: * hooks in the main loop, uses second-based timers and cannot offer good
21: * latency. The core of BFD protocol (the code related to BFD sessions,
22: * interfaces and packets) runs in the BFD thread, while the rest (the code
23: * related to BFD requests, BFD neighbors and the protocol glue) runs in the
24: * main thread.
25: *
26: * BFD sessions are represented by structure &bfd_session that contains a state
27: * related to the session and two timers (TX timer for periodic packets and hold
28: * timer for session timeout). These sessions are allocated from @session_slab
29: * and are accessible by two hash tables, @session_hash_id (by session ID) and
30: * @session_hash_ip (by IP addresses of neighbors). Slab and both hashes are in
31: * the main protocol structure &bfd_proto. The protocol logic related to BFD
32: * sessions is implemented in internal functions bfd_session_*(), which are
33: * expected to be called from the context of BFD thread, and external functions
34: * bfd_add_session(), bfd_remove_session() and bfd_reconfigure_session(), which
35: * form an interface to the BFD core for the rest and are expected to be called
36: * from the context of main thread.
37: *
38: * Each BFD session has an associated BFD interface, represented by structure
39: * &bfd_iface. A BFD interface contains a socket used for TX (the one for RX is
40: * shared in &bfd_proto), an interface configuration and reference counter.
41: * Compared to interface structures of other protocols, these structures are not
42: * created and removed based on interface notification events, but according to
43: * the needs of BFD sessions. When a new session is created, it requests a
44: * proper BFD interface by function bfd_get_iface(), which either finds an
45: * existing one in &iface_list (from &bfd_proto) or allocates a new one. When a
46: * session is removed, an associated iface is discharged by bfd_free_iface().
47: *
48: * BFD requests are the external API for the other protocols. When a protocol
49: * wants a BFD session, it calls bfd_request_session(), which creates a
50: * structure &bfd_request containing approprite information and an notify hook.
51: * This structure is a resource associated with the caller's resource pool. When
52: * a BFD protocol is available, a BFD request is submitted to the protocol, an
53: * appropriate BFD session is found or created and the request is attached to
54: * the session. When a session changes state, all attached requests (and related
55: * protocols) are notified. Note that BFD requests do not depend on BFD protocol
56: * running. When the BFD protocol is stopped or removed (or not available from
57: * beginning), related BFD requests are stored in @bfd_wait_list, where waits
58: * for a new protocol.
59: *
60: * BFD neighbors are just a way to statically configure BFD sessions without
61: * requests from other protocol. Structures &bfd_neighbor are part of BFD
62: * configuration (like static routes in the static protocol). BFD neighbors are
63: * handled by BFD protocol like it is a BFD client -- when a BFD neighbor is
64: * ready, the protocol just creates a BFD request like any other protocol.
65: *
66: * The protocol uses a new generic event loop (structure &birdloop) from |io.c|,
67: * which supports sockets, timers and events like the main loop. Timers
68: * (structure &timer2) are new microsecond based timers, while sockets and
69: * events are the same. A birdloop is associated with a thread (field @thread)
70: * in which event hooks are executed. Most functions for setting event sources
71: * (like sk_start() or tm2_start()) must be called from the context of that
72: * thread. Birdloop allows to temporarily acquire the context of that thread for
73: * the main thread by calling birdloop_enter() and then birdloop_leave(), which
74: * also ensures mutual exclusion with all event hooks. Note that resources
75: * associated with a birdloop (like timers) should be attached to the
76: * independent resource pool, detached from the main resource tree.
77: *
78: * There are two kinds of interaction between the BFD core (running in the BFD
79: * thread) and the rest of BFD (running in the main thread). The first kind are
80: * configuration calls from main thread to the BFD thread (like bfd_add_session()).
81: * These calls are synchronous and use birdloop_enter() mechanism for mutual
82: * exclusion. The second kind is a notification about session changes from the
83: * BFD thread to the main thread. This is done in an asynchronous way, sesions
84: * with pending notifications are linked (in the BFD thread) to @notify_list in
85: * &bfd_proto, and then bfd_notify_hook() in the main thread is activated using
86: * bfd_notify_kick() and a pipe. The hook then processes scheduled sessions and
87: * calls hooks from associated BFD requests. This @notify_list (and state fields
88: * in structure &bfd_session) is protected by a spinlock in &bfd_proto and
89: * functions bfd_lock_sessions() / bfd_unlock_sessions().
90: *
91: * There are few data races (accessing @p->p.debug from TRACE() from the BFD
92: * thread and accessing some some private fields of %bfd_session from
93: * bfd_show_sessions() from the main thread, but these are harmless (i hope).
94: *
95: * TODO: document functions and access restrictions for fields in BFD structures.
96: *
97: * Supported standards:
98: * - RFC 5880 - main BFD standard
99: * - RFC 5881 - BFD for IP links
100: * - RFC 5882 - generic application of BFD
101: * - RFC 5883 - BFD for multihop paths
102: */
103:
104: #include "bfd.h"
105:
106:
107: #define HASH_ID_KEY(n) n->loc_id
108: #define HASH_ID_NEXT(n) n->next_id
109: #define HASH_ID_EQ(a,b) a == b
110: #define HASH_ID_FN(k) k
111:
112: #define HASH_IP_KEY(n) n->addr
113: #define HASH_IP_NEXT(n) n->next_ip
114: #define HASH_IP_EQ(a,b) ipa_equal(a,b)
115: #define HASH_IP_FN(k) ipa_hash32(k)
116:
117: static list bfd_proto_list;
118: static list bfd_wait_list;
119:
120: const char *bfd_state_names[] = { "AdminDown", "Down", "Init", "Up" };
121:
122: static void bfd_session_set_min_tx(struct bfd_session *s, u32 val);
123: static struct bfd_iface *bfd_get_iface(struct bfd_proto *p, ip_addr local, struct iface *iface);
124: static void bfd_free_iface(struct bfd_iface *ifa);
125: static inline void bfd_notify_kick(struct bfd_proto *p);
126:
127:
128: /*
129: * BFD sessions
130: */
131:
132: static void
133: bfd_session_update_state(struct bfd_session *s, uint state, uint diag)
134: {
135: struct bfd_proto *p = s->ifa->bfd;
136: uint old_state = s->loc_state;
137: int notify;
138:
139: if (state == old_state)
140: return;
141:
142: TRACE(D_EVENTS, "Session to %I changed state from %s to %s",
143: s->addr, bfd_state_names[old_state], bfd_state_names[state]);
144:
145: bfd_lock_sessions(p);
146: s->loc_state = state;
147: s->loc_diag = diag;
148:
149: notify = !NODE_VALID(&s->n);
150: if (notify)
151: add_tail(&p->notify_list, &s->n);
152: bfd_unlock_sessions(p);
153:
154: if (state == BFD_STATE_UP)
155: bfd_session_set_min_tx(s, s->ifa->cf->min_tx_int);
156:
157: if (old_state == BFD_STATE_UP)
158: bfd_session_set_min_tx(s, s->ifa->cf->idle_tx_int);
159:
160: if (notify)
161: bfd_notify_kick(p);
162: }
163:
164: static void
165: bfd_session_update_tx_interval(struct bfd_session *s)
166: {
167: u32 tx_int = MAX(s->des_min_tx_int, s->rem_min_rx_int);
168: u32 tx_int_l = tx_int - (tx_int / 4); // 75 %
169: u32 tx_int_h = tx_int - (tx_int / 10); // 90 %
170:
171: s->tx_timer->recurrent = tx_int_l;
172: s->tx_timer->randomize = tx_int_h - tx_int_l;
173:
174: /* Do not set timer if no previous event */
175: if (!s->last_tx)
176: return;
177:
178: /* Set timer relative to last tx_timer event */
179: tm2_set(s->tx_timer, s->last_tx + tx_int_l);
180: }
181:
182: static void
183: bfd_session_update_detection_time(struct bfd_session *s, int kick)
184: {
185: btime timeout = (btime) MAX(s->req_min_rx_int, s->rem_min_tx_int) * s->rem_detect_mult;
186:
187: if (kick)
188: s->last_rx = current_time();
189:
190: if (!s->last_rx)
191: return;
192:
193: tm2_set(s->hold_timer, s->last_rx + timeout);
194: }
195:
196: static void
197: bfd_session_control_tx_timer(struct bfd_session *s, int reset)
198: {
199: // if (!s->opened) goto stop;
200:
201: if (s->passive && (s->rem_id == 0))
202: goto stop;
203:
204: if (s->rem_demand_mode &&
205: !s->poll_active &&
206: (s->loc_state == BFD_STATE_UP) &&
207: (s->rem_state == BFD_STATE_UP))
208: goto stop;
209:
210: if (s->rem_min_rx_int == 0)
211: goto stop;
212:
213: /* So TX timer should run */
214: if (reset || !tm2_active(s->tx_timer))
215: {
216: s->last_tx = 0;
217: tm2_start(s->tx_timer, 0);
218: }
219:
220: return;
221:
222: stop:
223: tm2_stop(s->tx_timer);
224: s->last_tx = 0;
225: }
226:
227: static void
228: bfd_session_request_poll(struct bfd_session *s, u8 request)
229: {
230: /* Not sure about this, but doing poll in this case does not make sense */
231: if (s->rem_id == 0)
232: return;
233:
234: s->poll_scheduled |= request;
235:
236: if (s->poll_active)
237: return;
238:
239: s->poll_active = s->poll_scheduled;
240: s->poll_scheduled = 0;
241:
242: bfd_session_control_tx_timer(s, 1);
243: }
244:
245: static void
246: bfd_session_terminate_poll(struct bfd_session *s)
247: {
248: u8 poll_done = s->poll_active & ~s->poll_scheduled;
249:
250: if (poll_done & BFD_POLL_TX)
251: s->des_min_tx_int = s->des_min_tx_new;
252:
253: if (poll_done & BFD_POLL_RX)
254: s->req_min_rx_int = s->req_min_rx_new;
255:
256: s->poll_active = s->poll_scheduled;
257: s->poll_scheduled = 0;
258:
259: /* Timers are updated by caller - bfd_session_process_ctl() */
260: }
261:
262: void
263: bfd_session_process_ctl(struct bfd_session *s, u8 flags, u32 old_tx_int, u32 old_rx_int)
264: {
265: if (s->poll_active && (flags & BFD_FLAG_FINAL))
266: bfd_session_terminate_poll(s);
267:
268: if ((s->des_min_tx_int != old_tx_int) || (s->rem_min_rx_int != old_rx_int))
269: bfd_session_update_tx_interval(s);
270:
271: bfd_session_update_detection_time(s, 1);
272:
273: /* Update session state */
274: int next_state = 0;
275: int diag = BFD_DIAG_NOTHING;
276:
277: switch (s->loc_state)
278: {
279: case BFD_STATE_ADMIN_DOWN:
280: return;
281:
282: case BFD_STATE_DOWN:
283: if (s->rem_state == BFD_STATE_DOWN) next_state = BFD_STATE_INIT;
284: else if (s->rem_state == BFD_STATE_INIT) next_state = BFD_STATE_UP;
285: break;
286:
287: case BFD_STATE_INIT:
288: if (s->rem_state == BFD_STATE_ADMIN_DOWN) next_state = BFD_STATE_DOWN, diag = BFD_DIAG_NEIGHBOR_DOWN;
289: else if (s->rem_state >= BFD_STATE_INIT) next_state = BFD_STATE_UP;
290: break;
291:
292: case BFD_STATE_UP:
293: if (s->rem_state <= BFD_STATE_DOWN) next_state = BFD_STATE_DOWN, diag = BFD_DIAG_NEIGHBOR_DOWN;
294: break;
295: }
296:
297: if (next_state)
298: bfd_session_update_state(s, next_state, diag);
299:
300: bfd_session_control_tx_timer(s, 0);
301:
302: if (flags & BFD_FLAG_POLL)
303: bfd_send_ctl(s->ifa->bfd, s, 1);
304: }
305:
306: static void
307: bfd_session_timeout(struct bfd_session *s)
308: {
309: struct bfd_proto *p = s->ifa->bfd;
310:
311: TRACE(D_EVENTS, "Session to %I expired", s->addr);
312:
313: s->rem_state = BFD_STATE_DOWN;
314: s->rem_id = 0;
315: s->rem_min_tx_int = 0;
316: s->rem_min_rx_int = 1;
317: s->rem_demand_mode = 0;
318: s->rem_detect_mult = 0;
319: s->rx_csn_known = 0;
320:
321: s->poll_active = 0;
322: s->poll_scheduled = 0;
323:
324: bfd_session_update_state(s, BFD_STATE_DOWN, BFD_DIAG_TIMEOUT);
325:
326: bfd_session_control_tx_timer(s, 1);
327: }
328:
329: static void
330: bfd_session_set_min_tx(struct bfd_session *s, u32 val)
331: {
332: /* Note that des_min_tx_int <= des_min_tx_new */
333:
334: if (val == s->des_min_tx_new)
335: return;
336:
337: s->des_min_tx_new = val;
338:
339: /* Postpone timer update if des_min_tx_int increases and the session is up */
340: if ((s->loc_state != BFD_STATE_UP) || (val < s->des_min_tx_int))
341: {
342: s->des_min_tx_int = val;
343: bfd_session_update_tx_interval(s);
344: }
345:
346: bfd_session_request_poll(s, BFD_POLL_TX);
347: }
348:
349: static void
350: bfd_session_set_min_rx(struct bfd_session *s, u32 val)
351: {
352: /* Note that req_min_rx_int >= req_min_rx_new */
353:
354: if (val == s->req_min_rx_new)
355: return;
356:
357: s->req_min_rx_new = val;
358:
359: /* Postpone timer update if req_min_rx_int decreases and the session is up */
360: if ((s->loc_state != BFD_STATE_UP) || (val > s->req_min_rx_int))
361: {
362: s->req_min_rx_int = val;
363: bfd_session_update_detection_time(s, 0);
364: }
365:
366: bfd_session_request_poll(s, BFD_POLL_RX);
367: }
368:
369: struct bfd_session *
370: bfd_find_session_by_id(struct bfd_proto *p, u32 id)
371: {
372: return HASH_FIND(p->session_hash_id, HASH_ID, id);
373: }
374:
375: struct bfd_session *
376: bfd_find_session_by_addr(struct bfd_proto *p, ip_addr addr)
377: {
378: return HASH_FIND(p->session_hash_ip, HASH_IP, addr);
379: }
380:
381: static void
382: bfd_tx_timer_hook(timer2 *t)
383: {
384: struct bfd_session *s = t->data;
385:
386: s->last_tx = current_time();
387: bfd_send_ctl(s->ifa->bfd, s, 0);
388: }
389:
390: static void
391: bfd_hold_timer_hook(timer2 *t)
392: {
393: bfd_session_timeout(t->data);
394: }
395:
396: static u32
397: bfd_get_free_id(struct bfd_proto *p)
398: {
399: u32 id;
400: for (id = random_u32(); 1; id++)
401: if (id && !bfd_find_session_by_id(p, id))
402: break;
403:
404: return id;
405: }
406:
407: static struct bfd_session *
408: bfd_add_session(struct bfd_proto *p, ip_addr addr, ip_addr local, struct iface *iface)
409: {
410: birdloop_enter(p->loop);
411:
412: struct bfd_iface *ifa = bfd_get_iface(p, local, iface);
413:
414: struct bfd_session *s = sl_alloc(p->session_slab);
415: bzero(s, sizeof(struct bfd_session));
416:
417: s->addr = addr;
418: s->ifa = ifa;
419: s->loc_id = bfd_get_free_id(p);
420:
421: HASH_INSERT(p->session_hash_id, HASH_ID, s);
422: HASH_INSERT(p->session_hash_ip, HASH_IP, s);
423:
424:
425: /* Initialization of state variables - see RFC 5880 6.8.1 */
426: s->loc_state = BFD_STATE_DOWN;
427: s->rem_state = BFD_STATE_DOWN;
428: s->des_min_tx_int = s->des_min_tx_new = ifa->cf->idle_tx_int;
429: s->req_min_rx_int = s->req_min_rx_new = ifa->cf->min_rx_int;
430: s->rem_min_rx_int = 1;
431: s->detect_mult = ifa->cf->multiplier;
432: s->passive = ifa->cf->passive;
433: s->tx_csn = random_u32();
434:
435: s->tx_timer = tm2_new_init(p->tpool, bfd_tx_timer_hook, s, 0, 0);
436: s->hold_timer = tm2_new_init(p->tpool, bfd_hold_timer_hook, s, 0, 0);
437: bfd_session_update_tx_interval(s);
438: bfd_session_control_tx_timer(s, 1);
439:
440: init_list(&s->request_list);
441: s->last_state_change = now;
442:
443: TRACE(D_EVENTS, "Session to %I added", s->addr);
444:
445: birdloop_leave(p->loop);
446:
447: return s;
448: }
449:
450: /*
451: static void
452: bfd_open_session(struct bfd_proto *p, struct bfd_session *s, ip_addr local, struct iface *ifa)
453: {
454: birdloop_enter(p->loop);
455:
456: s->opened = 1;
457:
458: bfd_session_control_tx_timer(s);
459:
460: birdloop_leave(p->loop);
461: }
462:
463: static void
464: bfd_close_session(struct bfd_proto *p, struct bfd_session *s)
465: {
466: birdloop_enter(p->loop);
467:
468: s->opened = 0;
469:
470: bfd_session_update_state(s, BFD_STATE_DOWN, BFD_DIAG_PATH_DOWN);
471: bfd_session_control_tx_timer(s);
472:
473: birdloop_leave(p->loop);
474: }
475: */
476:
477: static void
478: bfd_remove_session(struct bfd_proto *p, struct bfd_session *s)
479: {
480: ip_addr ip = s->addr;
481:
482: /* Caller should ensure that request list is empty */
483:
484: birdloop_enter(p->loop);
485:
486: /* Remove session from notify list if scheduled for notification */
487: /* No need for bfd_lock_sessions(), we are already protected by birdloop_enter() */
488: if (NODE_VALID(&s->n))
489: rem_node(&s->n);
490:
491: bfd_free_iface(s->ifa);
492:
493: rfree(s->tx_timer);
494: rfree(s->hold_timer);
495:
496: HASH_REMOVE(p->session_hash_id, HASH_ID, s);
497: HASH_REMOVE(p->session_hash_ip, HASH_IP, s);
498:
499: sl_free(p->session_slab, s);
500:
501: TRACE(D_EVENTS, "Session to %I removed", ip);
502:
503: birdloop_leave(p->loop);
504: }
505:
506: static void
507: bfd_reconfigure_session(struct bfd_proto *p, struct bfd_session *s)
508: {
509: birdloop_enter(p->loop);
510:
511: struct bfd_iface_config *cf = s->ifa->cf;
512:
513: u32 tx = (s->loc_state == BFD_STATE_UP) ? cf->min_tx_int : cf->idle_tx_int;
514: bfd_session_set_min_tx(s, tx);
515: bfd_session_set_min_rx(s, cf->min_rx_int);
516: s->detect_mult = cf->multiplier;
517: s->passive = cf->passive;
518:
519: bfd_session_control_tx_timer(s, 0);
520:
521: birdloop_leave(p->loop);
522:
523: TRACE(D_EVENTS, "Session to %I reconfigured", s->addr);
524: }
525:
526:
527: /*
528: * BFD interfaces
529: */
530:
531: static struct bfd_iface_config bfd_default_iface = {
532: .min_rx_int = BFD_DEFAULT_MIN_RX_INT,
533: .min_tx_int = BFD_DEFAULT_MIN_TX_INT,
534: .idle_tx_int = BFD_DEFAULT_IDLE_TX_INT,
535: .multiplier = BFD_DEFAULT_MULTIPLIER
536: };
537:
538: static inline struct bfd_iface_config *
539: bfd_find_iface_config(struct bfd_config *cf, struct iface *iface)
540: {
541: struct bfd_iface_config *ic;
542:
543: ic = iface ? (void *) iface_patt_find(&cf->patt_list, iface, NULL) : cf->multihop;
544:
545: return ic ? ic : &bfd_default_iface;
546: }
547:
548: static struct bfd_iface *
549: bfd_get_iface(struct bfd_proto *p, ip_addr local, struct iface *iface)
550: {
551: struct bfd_iface *ifa;
552:
553: WALK_LIST(ifa, p->iface_list)
554: if (ipa_equal(ifa->local, local) && (ifa->iface == iface))
555: return ifa->uc++, ifa;
556:
557: struct bfd_config *cf = (struct bfd_config *) (p->p.cf);
558: struct bfd_iface_config *ic = bfd_find_iface_config(cf, iface);
559:
560: ifa = mb_allocz(p->tpool, sizeof(struct bfd_iface));
561: ifa->local = local;
562: ifa->iface = iface;
563: ifa->cf = ic;
564: ifa->bfd = p;
565:
566: ifa->sk = bfd_open_tx_sk(p, local, iface);
567: ifa->uc = 1;
568:
569: add_tail(&p->iface_list, &ifa->n);
570:
571: return ifa;
572: }
573:
574: static void
575: bfd_free_iface(struct bfd_iface *ifa)
576: {
577: if (!ifa || --ifa->uc)
578: return;
579:
580: if (ifa->sk)
581: {
582: sk_stop(ifa->sk);
583: rfree(ifa->sk);
584: }
585:
586: rem_node(&ifa->n);
587: mb_free(ifa);
588: }
589:
590: static void
591: bfd_reconfigure_iface(struct bfd_proto *p, struct bfd_iface *ifa, struct bfd_config *nc)
592: {
593: struct bfd_iface_config *nic = bfd_find_iface_config(nc, ifa->iface);
594: ifa->changed = !!memcmp(nic, ifa->cf, sizeof(struct bfd_iface_config));
595:
596: /* This should be probably changed to not access ifa->cf from the BFD thread */
597: birdloop_enter(p->loop);
598: ifa->cf = nic;
599: birdloop_leave(p->loop);
600: }
601:
602:
603: /*
604: * BFD requests
605: */
606:
607: static void
608: bfd_request_notify(struct bfd_request *req, u8 state, u8 diag)
609: {
610: u8 old_state = req->state;
611:
612: if (state == old_state)
613: return;
614:
615: req->state = state;
616: req->diag = diag;
617: req->old_state = old_state;
618: req->down = (old_state == BFD_STATE_UP) && (state == BFD_STATE_DOWN);
619:
620: if (req->hook)
621: req->hook(req);
622: }
623:
624: static int
625: bfd_add_request(struct bfd_proto *p, struct bfd_request *req)
626: {
627: struct bfd_session *s = bfd_find_session_by_addr(p, req->addr);
628: u8 state, diag;
629:
630: if (!s)
631: s = bfd_add_session(p, req->addr, req->local, req->iface);
632:
633: rem_node(&req->n);
634: add_tail(&s->request_list, &req->n);
635: req->session = s;
636:
637: bfd_lock_sessions(p);
638: state = s->loc_state;
639: diag = s->loc_diag;
640: bfd_unlock_sessions(p);
641:
642: bfd_request_notify(req, state, diag);
643:
644: return 1;
645: }
646:
647: static void
648: bfd_submit_request(struct bfd_request *req)
649: {
650: node *n;
651:
652: WALK_LIST(n, bfd_proto_list)
653: if (bfd_add_request(SKIP_BACK(struct bfd_proto, bfd_node, n), req))
654: return;
655:
656: rem_node(&req->n);
657: add_tail(&bfd_wait_list, &req->n);
658: req->session = NULL;
659: bfd_request_notify(req, BFD_STATE_ADMIN_DOWN, 0);
660: }
661:
662: static void
663: bfd_take_requests(struct bfd_proto *p)
664: {
665: node *n, *nn;
666:
667: WALK_LIST_DELSAFE(n, nn, bfd_wait_list)
668: bfd_add_request(p, SKIP_BACK(struct bfd_request, n, n));
669: }
670:
671: static void
672: bfd_drop_requests(struct bfd_proto *p)
673: {
674: node *n;
675:
676: HASH_WALK(p->session_hash_id, next_id, s)
677: {
678: /* We assume that p is not in bfd_proto_list */
679: WALK_LIST_FIRST(n, s->request_list)
680: bfd_submit_request(SKIP_BACK(struct bfd_request, n, n));
681: }
682: HASH_WALK_END;
683: }
684:
685: static struct resclass bfd_request_class;
686:
687: struct bfd_request *
688: bfd_request_session(pool *p, ip_addr addr, ip_addr local, struct iface *iface,
689: void (*hook)(struct bfd_request *), void *data)
690: {
691: struct bfd_request *req = ralloc(p, &bfd_request_class);
692:
693: /* Hack: self-link req->n, we will call rem_node() on it */
694: req->n.prev = req->n.next = &req->n;
695:
696: req->addr = addr;
697: req->local = local;
698: req->iface = iface;
699:
700: bfd_submit_request(req);
701:
702: req->hook = hook;
703: req->data = data;
704:
705: return req;
706: }
707:
708: static void
709: bfd_request_free(resource *r)
710: {
711: struct bfd_request *req = (struct bfd_request *) r;
712: struct bfd_session *s = req->session;
713:
714: rem_node(&req->n);
715:
716: /* Remove the session if there is no request for it. Skip that if
717: inside notify hooks, will be handled by bfd_notify_hook() itself */
718:
719: if (s && EMPTY_LIST(s->request_list) && !s->notify_running)
720: bfd_remove_session(s->ifa->bfd, s);
721: }
722:
723: static void
724: bfd_request_dump(resource *r)
725: {
726: struct bfd_request *req = (struct bfd_request *) r;
727:
728: debug("(code %p, data %p)\n", req->hook, req->data);
729: }
730:
731: static struct resclass bfd_request_class = {
732: "BFD request",
733: sizeof(struct bfd_request),
734: bfd_request_free,
735: bfd_request_dump,
736: NULL,
737: NULL
738: };
739:
740:
741: /*
742: * BFD neighbors
743: */
744:
745: static void
746: bfd_neigh_notify(struct neighbor *nb)
747: {
748: struct bfd_proto *p = (struct bfd_proto *) nb->proto;
749: struct bfd_neighbor *n = nb->data;
750:
751: if (!n)
752: return;
753:
754: if ((nb->scope > 0) && !n->req)
755: {
756: ip_addr local = ipa_nonzero(n->local) ? n->local : nb->ifa->ip;
757: n->req = bfd_request_session(p->p.pool, n->addr, local, nb->iface, NULL, NULL);
758: }
759:
760: if ((nb->scope <= 0) && n->req)
761: {
762: rfree(n->req);
763: n->req = NULL;
764: }
765: }
766:
767: static void
768: bfd_start_neighbor(struct bfd_proto *p, struct bfd_neighbor *n)
769: {
770: n->active = 1;
771:
772: if (n->multihop)
773: {
774: n->req = bfd_request_session(p->p.pool, n->addr, n->local, NULL, NULL, NULL);
775: return;
776: }
777:
778: struct neighbor *nb = neigh_find2(&p->p, &n->addr, n->iface, NEF_STICKY);
779: if (!nb)
780: {
781: log(L_ERR "%s: Invalid remote address %I%J", p->p.name, n->addr, n->iface);
782: return;
783: }
784:
785: if (nb->data)
786: {
787: log(L_ERR "%s: Duplicate neighbor %I", p->p.name, n->addr);
788: return;
789: }
790:
791: n->neigh = nb;
792: nb->data = n;
793:
794: if (nb->scope > 0)
795: bfd_neigh_notify(nb);
796: else
797: TRACE(D_EVENTS, "Waiting for %I%J to become my neighbor", n->addr, n->iface);
798: }
799:
800: static void
801: bfd_stop_neighbor(struct bfd_proto *p UNUSED, struct bfd_neighbor *n)
802: {
803: if (n->neigh)
804: n->neigh->data = NULL;
805: n->neigh = NULL;
806:
807: rfree(n->req);
808: n->req = NULL;
809: }
810:
811: static inline int
812: bfd_same_neighbor(struct bfd_neighbor *x, struct bfd_neighbor *y)
813: {
814: return ipa_equal(x->addr, y->addr) && ipa_equal(x->local, y->local) &&
815: (x->iface == y->iface) && (x->multihop == y->multihop);
816: }
817:
818: static void
819: bfd_reconfigure_neighbors(struct bfd_proto *p, struct bfd_config *new)
820: {
821: struct bfd_config *old = (struct bfd_config *) (p->p.cf);
822: struct bfd_neighbor *on, *nn;
823:
824: WALK_LIST(on, old->neigh_list)
825: {
826: WALK_LIST(nn, new->neigh_list)
827: if (bfd_same_neighbor(nn, on))
828: {
829: nn->neigh = on->neigh;
830: if (nn->neigh)
831: nn->neigh->data = nn;
832:
833: nn->req = on->req;
834: nn->active = 1;
835: return;
836: }
837:
838: bfd_stop_neighbor(p, on);
839: }
840:
841: WALK_LIST(nn, new->neigh_list)
842: if (!nn->active)
843: bfd_start_neighbor(p, nn);
844: }
845:
846:
847: /*
848: * BFD notify socket
849: */
850:
851: /* This core notify code should be replaced after main loop transition to birdloop */
852:
853: int pipe(int pipefd[2]);
854: void pipe_drain(int fd);
855: void pipe_kick(int fd);
856:
857: static int
858: bfd_notify_hook(sock *sk, uint len UNUSED)
859: {
860: struct bfd_proto *p = sk->data;
861: struct bfd_session *s;
862: list tmp_list;
863: u8 state, diag;
864: node *n, *nn;
865:
866: pipe_drain(sk->fd);
867:
868: bfd_lock_sessions(p);
869: init_list(&tmp_list);
870: add_tail_list(&tmp_list, &p->notify_list);
871: init_list(&p->notify_list);
872: bfd_unlock_sessions(p);
873:
874: WALK_LIST_FIRST(s, tmp_list)
875: {
876: bfd_lock_sessions(p);
877: rem_node(&s->n);
878: state = s->loc_state;
879: diag = s->loc_diag;
880: bfd_unlock_sessions(p);
881:
882: /* FIXME: convert to btime and move to bfd_session_update_state() */
883: s->last_state_change = now;
884:
885: s->notify_running = 1;
886: WALK_LIST_DELSAFE(n, nn, s->request_list)
887: bfd_request_notify(SKIP_BACK(struct bfd_request, n, n), state, diag);
888: s->notify_running = 0;
889:
890: /* Remove the session if all requests were removed in notify hooks */
891: if (EMPTY_LIST(s->request_list))
892: bfd_remove_session(p, s);
893: }
894:
895: return 0;
896: }
897:
898: static inline void
899: bfd_notify_kick(struct bfd_proto *p)
900: {
901: pipe_kick(p->notify_ws->fd);
902: }
903:
904: static void
905: bfd_noterr_hook(sock *sk, int err)
906: {
907: struct bfd_proto *p = sk->data;
908: log(L_ERR "%s: Notify socket error: %m", p->p.name, err);
909: }
910:
911: static void
912: bfd_notify_init(struct bfd_proto *p)
913: {
914: int pfds[2];
915: sock *sk;
916:
917: int rv = pipe(pfds);
918: if (rv < 0)
919: die("pipe: %m");
920:
921: sk = sk_new(p->p.pool);
922: sk->type = SK_MAGIC;
923: sk->rx_hook = bfd_notify_hook;
924: sk->err_hook = bfd_noterr_hook;
925: sk->fd = pfds[0];
926: sk->data = p;
927: if (sk_open(sk) < 0)
928: die("bfd: sk_open failed");
929: p->notify_rs = sk;
930:
931: /* The write sock is not added to any event loop */
932: sk = sk_new(p->p.pool);
933: sk->type = SK_MAGIC;
934: sk->fd = pfds[1];
935: sk->data = p;
936: sk->flags = SKF_THREAD;
937: if (sk_open(sk) < 0)
938: die("bfd: sk_open failed");
939: p->notify_ws = sk;
940: }
941:
942:
943: /*
944: * BFD protocol glue
945: */
946:
947: void
948: bfd_init_all(void)
949: {
950: init_list(&bfd_proto_list);
951: init_list(&bfd_wait_list);
952: }
953:
954: static struct proto *
955: bfd_init(struct proto_config *c)
956: {
957: struct proto *p = proto_new(c, sizeof(struct bfd_proto));
958:
959: p->neigh_notify = bfd_neigh_notify;
960:
961: return p;
962: }
963:
964: static int
965: bfd_start(struct proto *P)
966: {
967: struct bfd_proto *p = (struct bfd_proto *) P;
968: struct bfd_config *cf = (struct bfd_config *) (P->cf);
969:
970: p->loop = birdloop_new();
971: p->tpool = rp_new(NULL, "BFD thread root");
972: pthread_spin_init(&p->lock, PTHREAD_PROCESS_PRIVATE);
973:
974: p->session_slab = sl_new(P->pool, sizeof(struct bfd_session));
975: HASH_INIT(p->session_hash_id, P->pool, 8);
976: HASH_INIT(p->session_hash_ip, P->pool, 8);
977:
978: init_list(&p->iface_list);
979:
980: init_list(&p->notify_list);
981: bfd_notify_init(p);
982:
983: add_tail(&bfd_proto_list, &p->bfd_node);
984:
985: birdloop_enter(p->loop);
986: p->rx_1 = bfd_open_rx_sk(p, 0);
987: p->rx_m = bfd_open_rx_sk(p, 1);
988: birdloop_leave(p->loop);
989:
990: bfd_take_requests(p);
991:
992: struct bfd_neighbor *n;
993: WALK_LIST(n, cf->neigh_list)
994: bfd_start_neighbor(p, n);
995:
996: birdloop_start(p->loop);
997:
998: return PS_UP;
999: }
1000:
1001:
1002: static int
1003: bfd_shutdown(struct proto *P)
1004: {
1005: struct bfd_proto *p = (struct bfd_proto *) P;
1006: struct bfd_config *cf = (struct bfd_config *) (P->cf);
1007:
1008: rem_node(&p->bfd_node);
1009:
1010: birdloop_stop(p->loop);
1011:
1012: struct bfd_neighbor *n;
1013: WALK_LIST(n, cf->neigh_list)
1014: bfd_stop_neighbor(p, n);
1015:
1016: bfd_drop_requests(p);
1017:
1018: /* FIXME: This is hack */
1019: birdloop_enter(p->loop);
1020: rfree(p->tpool);
1021: birdloop_leave(p->loop);
1022:
1023: birdloop_free(p->loop);
1024:
1025: return PS_DOWN;
1026: }
1027:
1028: static int
1029: bfd_reconfigure(struct proto *P, struct proto_config *c)
1030: {
1031: struct bfd_proto *p = (struct bfd_proto *) P;
1032: // struct bfd_config *old = (struct bfd_config *) (P->cf);
1033: struct bfd_config *new = (struct bfd_config *) c;
1034: struct bfd_iface *ifa;
1035:
1036: birdloop_mask_wakeups(p->loop);
1037:
1038: WALK_LIST(ifa, p->iface_list)
1039: bfd_reconfigure_iface(p, ifa, new);
1040:
1041: HASH_WALK(p->session_hash_id, next_id, s)
1042: {
1043: if (s->ifa->changed)
1044: bfd_reconfigure_session(p, s);
1045: }
1046: HASH_WALK_END;
1047:
1048: bfd_reconfigure_neighbors(p, new);
1049:
1050: birdloop_unmask_wakeups(p->loop);
1051:
1052: return 1;
1053: }
1054:
1055: /* Ensure one instance */
1056: struct bfd_config *bfd_cf;
1057:
1058: static void
1059: bfd_preconfig(struct protocol *P UNUSED, struct config *c UNUSED)
1060: {
1061: bfd_cf = NULL;
1062: }
1063:
1064: static void
1065: bfd_copy_config(struct proto_config *dest, struct proto_config *src UNUSED)
1066: {
1067: struct bfd_config *d = (struct bfd_config *) dest;
1068: // struct bfd_config *s = (struct bfd_config *) src;
1069:
1070: /* We clean up patt_list and neigh_list, neighbors and ifaces are non-sharable */
1071: init_list(&d->patt_list);
1072: init_list(&d->neigh_list);
1073: }
1074:
1075: void
1076: bfd_show_sessions(struct proto *P)
1077: {
1078: byte tbuf[TM_DATETIME_BUFFER_SIZE];
1079: struct bfd_proto *p = (struct bfd_proto *) P;
1080: uint state, diag UNUSED;
1081: u32 tx_int, timeout;
1082: const char *ifname;
1083:
1084: if (p->p.proto_state != PS_UP)
1085: {
1086: cli_msg(-1020, "%s: is not up", p->p.name);
1087: cli_msg(0, "");
1088: return;
1089: }
1090:
1091: cli_msg(-1020, "%s:", p->p.name);
1092: cli_msg(-1020, "%-25s %-10s %-10s %-10s %8s %8s",
1093: "IP address", "Interface", "State", "Since", "Interval", "Timeout");
1094:
1095:
1096: HASH_WALK(p->session_hash_id, next_id, s)
1097: {
1098: /* FIXME: this is thread-unsafe, but perhaps harmless */
1099: state = s->loc_state;
1100: diag = s->loc_diag;
1101: ifname = (s->ifa && s->ifa->iface) ? s->ifa->iface->name : "---";
1102: tx_int = s->last_tx ? (MAX(s->des_min_tx_int, s->rem_min_rx_int) TO_MS) : 0;
1103: timeout = (MAX(s->req_min_rx_int, s->rem_min_tx_int) TO_MS) * s->rem_detect_mult;
1104:
1105: state = (state < 4) ? state : 0;
1106: tm_format_datetime(tbuf, &config->tf_proto, s->last_state_change);
1107:
1108: cli_msg(-1020, "%-25I %-10s %-10s %-10s %3u.%03u %3u.%03u",
1109: s->addr, ifname, bfd_state_names[state], tbuf,
1110: tx_int / 1000, tx_int % 1000, timeout / 1000, timeout % 1000);
1111: }
1112: HASH_WALK_END;
1113:
1114: cli_msg(0, "");
1115: }
1116:
1117:
1118: struct protocol proto_bfd = {
1119: .name = "BFD",
1120: .template = "bfd%d",
1121: .config_size = sizeof(struct bfd_config),
1122: .init = bfd_init,
1123: .start = bfd_start,
1124: .shutdown = bfd_shutdown,
1125: .reconfigure = bfd_reconfigure,
1126: .preconfig = bfd_preconfig,
1127: .copy_config = bfd_copy_config,
1128: };
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