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iof-bird-daemon / proto / bfd / bfd.c @ 2d0b7e24

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/*
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 *        BIRD -- Bidirectional Forwarding Detection (BFD)
3
 *
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 *        Can be freely distributed and used under the terms of the GNU GPL.
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 */
6

    
7
/**
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 * DOC: Bidirectional Forwarding Detection
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 *
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 * The BFD protocol is implemented in three files: |bfd.c| containing the
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 * protocol logic and the protocol glue with BIRD core, |packets.c| handling BFD
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 * packet processing, RX, TX and protocol sockets. |io.c| then contains generic
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 * code for the event loop, threads and event sources (sockets, microsecond
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 * timers). This generic code will be merged to the main BIRD I/O code in the
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 * future.
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 *
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 * The BFD implementation uses a separate thread with an internal event loop for
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 * handling the protocol logic, which requires high-res and low-latency timing,
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 * so it is not affected by the rest of BIRD, which has several low-granularity
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 * hooks in the main loop, uses second-based timers and cannot offer good
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 * latency. The core of BFD protocol (the code related to BFD sessions,
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 * interfaces and packets) runs in the BFD thread, while the rest (the code
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 * related to BFD requests, BFD neighbors and the protocol glue) runs in the
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 * main thread.
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 *
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 * BFD sessions are represented by structure &bfd_session that contains a state
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 * related to the session and two timers (TX timer for periodic packets and hold
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 * timer for session timeout). These sessions are allocated from @session_slab
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 * and are accessible by two hash tables, @session_hash_id (by session ID) and
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 * @session_hash_ip (by IP addresses of neighbors). Slab and both hashes are in
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 * the main protocol structure &bfd_proto. The protocol logic related to BFD
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 * sessions is implemented in internal functions bfd_session_*(), which are
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 * expected to be called from the context of BFD thread, and external functions
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 * bfd_add_session(), bfd_remove_session() and bfd_reconfigure_session(), which
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 * form an interface to the BFD core for the rest and are expected to be called
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 * from the context of main thread.
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 *
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 * Each BFD session has an associated BFD interface, represented by structure
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 * &bfd_iface. A BFD interface contains a socket used for TX (the one for RX is
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 * shared in &bfd_proto), an interface configuration and reference counter.
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 * Compared to interface structures of other protocols, these structures are not
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 * created and removed based on interface notification events, but according to
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 * 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
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 * session is removed, an associated iface is dicharged by bfd_free_iface().
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 *
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 * BFD requests are the external API for the other protocols. When a protocol
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 * wants a BFD session, it calls bfd_request_session(), which creates a
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 * structure &bfd_request containing approprite information and an notify hook.
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 * This structure is a resource associated with the caller's resource pool. When
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 * a BFD protocol is available, a BFD request is submitted to the protocol, an
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 * appropriate BFD session is found or created and the request is attached to
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 * the session. When a session changes state, all attached requests (and related
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 * 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
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 * configuration (like static routes in the static protocol). BFD neighbors are
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 * handled by BFD protocol like it is a BFD client -- when a BFD neighbor is
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 * 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|,
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 * which supports sockets, timers and events like the main loop. Timers
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 * (structure &timer2) are new microsecond based timers, while sockets and
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 * 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
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 * (like sk_start() or tm2_start()) must be called from the context of that
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 * thread. Birdloop allows to temporarily acquire the context of that thread for
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 * the main thread by calling birdloop_enter() and then birdloop_leave(), which
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 * also ensures mutual exclusion with all event hooks. Note that resources
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 * associated with a birdloop (like timers) should be attached to the
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 * independent resource pool, detached from the main resource tree.
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 *
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 * There are two kinds of interaction between the BFD core (running in the BFD
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 * thread) and the rest of BFD (running in the main thread). The first kind are
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 * 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
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 * 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:
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 * - 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_hash(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

    
320
  s->poll_active = 0;
321
  s->poll_scheduled = 0;
322

    
323
  bfd_session_update_state(s, BFD_STATE_DOWN, BFD_DIAG_TIMEOUT);
324

    
325
  bfd_session_control_tx_timer(s, 1);
326
}
327

    
328
static void
329
bfd_session_set_min_tx(struct bfd_session *s, u32 val)
330
{
331
  /* Note that des_min_tx_int <= des_min_tx_new */
332

    
333
  if (val == s->des_min_tx_new)
334
    return;
335

    
336
  s->des_min_tx_new = val;
337

    
338
  /* Postpone timer update if des_min_tx_int increases and the session is up */
339
  if ((s->loc_state != BFD_STATE_UP) || (val < s->des_min_tx_int))
340
  {
341
    s->des_min_tx_int = val;
342
    bfd_session_update_tx_interval(s);
343
  }
344

    
345
  bfd_session_request_poll(s, BFD_POLL_TX);
346
}
347

    
348
static void
349
bfd_session_set_min_rx(struct bfd_session *s, u32 val)
350
{
351
  /* Note that req_min_rx_int >= req_min_rx_new */
352

    
353
  if (val == s->req_min_rx_new)
354
    return;
355

    
356
  s->req_min_rx_new = val; 
357

    
358
  /* Postpone timer update if req_min_rx_int decreases and the session is up */
359
  if ((s->loc_state != BFD_STATE_UP) || (val > s->req_min_rx_int))
360
  {
361
    s->req_min_rx_int = val;
362
    bfd_session_update_detection_time(s, 0);
363
  }
364

    
365
  bfd_session_request_poll(s, BFD_POLL_RX);
366
}
367

    
368
struct bfd_session *
369
bfd_find_session_by_id(struct bfd_proto *p, u32 id)
370
{
371
  return HASH_FIND(p->session_hash_id, HASH_ID, id);
372
}
373

    
374
struct bfd_session *
375
bfd_find_session_by_addr(struct bfd_proto *p, ip_addr addr)
376
{
377
  return HASH_FIND(p->session_hash_ip, HASH_IP, addr);
378
}
379

    
380
static void
381
bfd_tx_timer_hook(timer2 *t)
382
{
383
  struct bfd_session *s = t->data;
384

    
385
  s->last_tx = current_time();
386
  bfd_send_ctl(s->ifa->bfd, s, 0);
387
}
388

    
389
static void
390
bfd_hold_timer_hook(timer2 *t)
391
{
392
  bfd_session_timeout(t->data);
393
}
394

    
395
static u32
396
bfd_get_free_id(struct bfd_proto *p)
397
{
398
  u32 id;
399
  for (id = random_u32(); 1; id++)
400
    if (id && !bfd_find_session_by_id(p, id))
401
      break;
402

    
403
  return id;
404
}
405

    
406
static struct bfd_session *
407
bfd_add_session(struct bfd_proto *p, ip_addr addr, ip_addr local, struct iface *iface)
408
{
409
  birdloop_enter(p->loop);
410

    
411
  struct bfd_iface *ifa = bfd_get_iface(p, local, iface);
412

    
413
  struct bfd_session *s = sl_alloc(p->session_slab);
414
  bzero(s, sizeof(struct bfd_session));
415

    
416
  s->addr = addr;
417
  s->ifa = ifa;
418
  s->loc_id = bfd_get_free_id(p);
419

    
420
  HASH_INSERT(p->session_hash_id, HASH_ID, s);
421
  HASH_INSERT(p->session_hash_ip, HASH_IP, s);
422

    
423

    
424
  /* Initialization of state variables - see RFC 5880 6.8.1 */
425
  s->loc_state = BFD_STATE_DOWN;
426
  s->rem_state = BFD_STATE_DOWN;
427
  s->des_min_tx_int = s->des_min_tx_new = ifa->cf->idle_tx_int;
428
  s->req_min_rx_int = s->req_min_rx_new = ifa->cf->min_rx_int;
429
  s->rem_min_rx_int = 1;
430
  s->detect_mult = ifa->cf->multiplier;
431
  s->passive = ifa->cf->passive;
432

    
433
  s->tx_timer = tm2_new_init(p->tpool, bfd_tx_timer_hook, s, 0, 0);
434
  s->hold_timer = tm2_new_init(p->tpool, bfd_hold_timer_hook, s, 0, 0);
435
  bfd_session_update_tx_interval(s);
436
  bfd_session_control_tx_timer(s, 1);
437

    
438
  init_list(&s->request_list);
439
  s->last_state_change = now;
440

    
441
  TRACE(D_EVENTS, "Session to %I added", s->addr);
442

    
443
  birdloop_leave(p->loop);
444

    
445
  return s;
446
}
447

    
448
/*
449
static void
450
bfd_open_session(struct bfd_proto *p, struct bfd_session *s, ip_addr local, struct iface *ifa)
451
{
452
  birdloop_enter(p->loop);
453

454
  s->opened = 1;
455

456
  bfd_session_control_tx_timer(s);
457

458
  birdloop_leave(p->loop);
459
}
460

461
static void
462
bfd_close_session(struct bfd_proto *p, struct bfd_session *s)
463
{
464
  birdloop_enter(p->loop);
465

466
  s->opened = 0;
467

468
  bfd_session_update_state(s, BFD_STATE_DOWN, BFD_DIAG_PATH_DOWN);
469
  bfd_session_control_tx_timer(s);
470

471
  birdloop_leave(p->loop);
472
}
473
*/
474

    
475
static void
476
bfd_remove_session(struct bfd_proto *p, struct bfd_session *s)
477
{
478
  ip_addr ip = s->addr;
479

    
480
  birdloop_enter(p->loop);
481

    
482
  bfd_free_iface(s->ifa);
483

    
484
  rfree(s->tx_timer);
485
  rfree(s->hold_timer);
486

    
487
  HASH_REMOVE(p->session_hash_id, HASH_ID, s);
488
  HASH_REMOVE(p->session_hash_ip, HASH_IP, s);
489

    
490
  sl_free(p->session_slab, s);
491

    
492
  TRACE(D_EVENTS, "Session to %I removed", ip);
493

    
494
  birdloop_leave(p->loop);
495
}
496

    
497
static void
498
bfd_reconfigure_session(struct bfd_proto *p, struct bfd_session *s)
499
{
500
  birdloop_enter(p->loop);
501

    
502
  struct bfd_iface_config *cf = s->ifa->cf;
503

    
504
  u32 tx = (s->loc_state == BFD_STATE_UP) ? cf->min_tx_int : cf->idle_tx_int;
505
  bfd_session_set_min_tx(s, tx);
506
  bfd_session_set_min_rx(s, cf->min_rx_int);
507
  s->detect_mult = cf->multiplier;
508
  s->passive = cf->passive;
509

    
510
  bfd_session_control_tx_timer(s, 0);
511

    
512
  birdloop_leave(p->loop);
513

    
514
  TRACE(D_EVENTS, "Session to %I reconfigured", s->addr);
515
}
516

    
517

    
518
/*
519
 *        BFD interfaces
520
 */
521

    
522
static struct bfd_iface_config bfd_default_iface = {
523
  .min_rx_int = BFD_DEFAULT_MIN_RX_INT,
524
  .min_tx_int = BFD_DEFAULT_MIN_TX_INT,
525
  .idle_tx_int = BFD_DEFAULT_IDLE_TX_INT,
526
  .multiplier = BFD_DEFAULT_MULTIPLIER
527
};
528

    
529
static inline struct bfd_iface_config *
530
bfd_find_iface_config(struct bfd_config *cf, struct iface *iface)
531
{
532
  struct bfd_iface_config *ic;
533

    
534
  ic = iface ? (void *) iface_patt_find(&cf->patt_list, iface, NULL) : cf->multihop;
535

    
536
  return ic ? ic : &bfd_default_iface;
537
}
538

    
539
static struct bfd_iface *
540
bfd_get_iface(struct bfd_proto *p, ip_addr local, struct iface *iface)
541
{
542
  struct bfd_iface *ifa;
543

    
544
  WALK_LIST(ifa, p->iface_list)
545
    if (ipa_equal(ifa->local, local) && (ifa->iface == iface))
546
      return ifa->uc++, ifa;
547

    
548
  struct bfd_config *cf = (struct bfd_config *) (p->p.cf);
549
  struct bfd_iface_config *ic = bfd_find_iface_config(cf, iface);
550

    
551
  ifa = mb_allocz(p->tpool, sizeof(struct bfd_iface));
552
  ifa->local = local;
553
  ifa->iface = iface;
554
  ifa->cf = ic;
555
  ifa->bfd = p;
556

    
557
  ifa->sk = bfd_open_tx_sk(p, local, iface);
558
  ifa->uc = 1;
559

    
560
  add_tail(&p->iface_list, &ifa->n);
561

    
562
  return ifa;
563
}
564

    
565
static void
566
bfd_free_iface(struct bfd_iface *ifa)
567
{
568
  if (!ifa || --ifa->uc)
569
    return;
570

    
571
  rem_node(&ifa->n);
572
  sk_stop(ifa->sk);
573
  rfree(ifa->sk);
574
  mb_free(ifa);
575
}
576

    
577
static void
578
bfd_reconfigure_iface(struct bfd_proto *p, struct bfd_iface *ifa, struct bfd_config *nc)
579
{
580
  struct bfd_iface_config *nic = bfd_find_iface_config(nc, ifa->iface);
581
  ifa->changed = !!memcmp(nic, ifa->cf, sizeof(struct bfd_iface_config));
582

    
583
  /* This should be probably changed to not access ifa->cf from the BFD thread */
584
  birdloop_enter(p->loop);
585
  ifa->cf = nic;
586
  birdloop_leave(p->loop);
587
}
588

    
589

    
590
/*
591
 *        BFD requests
592
 */
593

    
594
static void
595
bfd_request_notify(struct bfd_request *req, u8 state, u8 diag)
596
{
597
  u8 old_state = req->state;
598

    
599
  if (state == old_state)
600
    return;
601

    
602
  req->state = state;
603
  req->diag = diag;
604
  req->old_state = old_state;
605
  req->down = (old_state == BFD_STATE_UP) && (state == BFD_STATE_DOWN);
606

    
607
  if (req->hook)
608
    req->hook(req);
609
}
610

    
611
static int
612
bfd_add_request(struct bfd_proto *p, struct bfd_request *req)
613
{
614
  struct bfd_session *s = bfd_find_session_by_addr(p, req->addr);
615
  u8 state, diag;
616

    
617
  if (!s)
618
    s = bfd_add_session(p, req->addr, req->local, req->iface);
619

    
620
  rem_node(&req->n);
621
  add_tail(&s->request_list, &req->n);
622
  req->session = s;
623

    
624
  bfd_lock_sessions(p);
625
  state = s->loc_state;
626
  diag = s->loc_diag;
627
  bfd_unlock_sessions(p);
628

    
629
  bfd_request_notify(req, state, diag);
630

    
631
  return 1;
632
}
633

    
634
static void
635
bfd_submit_request(struct bfd_request *req)
636
{
637
  node *n;
638

    
639
  WALK_LIST(n, bfd_proto_list)
640
    if (bfd_add_request(SKIP_BACK(struct bfd_proto, bfd_node, n), req))
641
      return;
642

    
643
  rem_node(&req->n);
644
  add_tail(&bfd_wait_list, &req->n);
645
  req->session = NULL;
646
  bfd_request_notify(req, BFD_STATE_ADMIN_DOWN, 0);
647
}
648

    
649
static void
650
bfd_take_requests(struct bfd_proto *p)
651
{
652
  node *n, *nn;
653

    
654
  WALK_LIST_DELSAFE(n, nn, bfd_wait_list)
655
    bfd_add_request(p, SKIP_BACK(struct bfd_request, n, n));
656
}
657

    
658
static void
659
bfd_drop_requests(struct bfd_proto *p)
660
{
661
  node *n;
662

    
663
  HASH_WALK(p->session_hash_id, next_id, s)
664
  {
665
    /* We assume that p is not in bfd_proto_list */
666
    WALK_LIST_FIRST(n, s->request_list)
667
      bfd_submit_request(SKIP_BACK(struct bfd_request, n, n));
668
  }
669
  HASH_WALK_END;
670
}
671

    
672
static struct resclass bfd_request_class;
673

    
674
struct bfd_request *
675
bfd_request_session(pool *p, ip_addr addr, ip_addr local, struct iface *iface,
676
                    void (*hook)(struct bfd_request *), void *data)
677
{
678
  struct bfd_request *req = ralloc(p, &bfd_request_class);
679

    
680
  /* Hack: self-link req->n, we will call rem_node() on it */
681
  req->n.prev = req->n.next = &req->n;
682

    
683
  req->addr = addr;
684
  req->local = local;
685
  req->iface = iface;
686

    
687
  bfd_submit_request(req);
688

    
689
  req->hook = hook;
690
  req->data = data;
691

    
692
  return req;
693
}
694

    
695
static void
696
bfd_request_free(resource *r)
697
{
698
  struct bfd_request *req = (struct bfd_request *) r;
699
  struct bfd_session *s = req->session;
700

    
701
  rem_node(&req->n);
702

    
703
  /* Remove the session if there is no request for it. Skip that if
704
     inside notify hooks, will be handled by bfd_notify_hook() itself */
705

    
706
  if (s && EMPTY_LIST(s->request_list) && !s->notify_running)
707
    bfd_remove_session(s->ifa->bfd, s);
708
}
709

    
710
static void
711
bfd_request_dump(resource *r)
712
{
713
  struct bfd_request *req = (struct bfd_request *) r;
714

    
715
  debug("(code %p, data %p)\n", req->hook, req->data);
716
}
717

    
718
static struct resclass bfd_request_class = {
719
  "BFD request",
720
  sizeof(struct bfd_request),
721
  bfd_request_free,
722
  bfd_request_dump,
723
  NULL,
724
  NULL
725
};
726

    
727

    
728
/*
729
 *        BFD neighbors
730
 */
731

    
732
static void
733
bfd_neigh_notify(struct neighbor *nb)
734
{
735
  struct bfd_proto *p = (struct bfd_proto *) nb->proto;
736
  struct bfd_neighbor *n = nb->data;
737

    
738
  if (!n)
739
    return;
740

    
741
  if ((nb->scope > 0) && !n->req)
742
  {
743
    ip_addr local = ipa_nonzero(n->local) ? n->local : nb->ifa->ip;
744
    n->req = bfd_request_session(p->p.pool, n->addr, local, nb->iface, NULL, NULL);
745
  }
746

    
747
  if ((nb->scope <= 0) && n->req)
748
  {
749
    rfree(n->req);
750
    n->req = NULL;
751
  }
752
}
753

    
754
static void
755
bfd_start_neighbor(struct bfd_proto *p, struct bfd_neighbor *n)
756
{
757
  n->active = 1;
758

    
759
  if (n->multihop)
760
  {
761
    n->req = bfd_request_session(p->p.pool, n->addr, n->local, NULL, NULL, NULL);
762
    return;
763
  }
764

    
765
  struct neighbor *nb = neigh_find2(&p->p, &n->addr, n->iface, NEF_STICKY);
766
  if (!nb)
767
  {
768
    log(L_ERR "%s: Invalid remote address %I%J", p->p.name, n->addr, n->iface);
769
    return;
770
  }
771

    
772
  if (nb->data)
773
  {
774
    log(L_ERR "%s: Duplicate neighbor %I", p->p.name, n->addr);
775
    return;
776
  }
777

    
778
  n->neigh = nb;
779
  nb->data = n;
780

    
781
  if (nb->scope > 0)
782
    bfd_neigh_notify(nb);
783
  else
784
    TRACE(D_EVENTS, "Waiting for %I%J to become my neighbor", n->addr, n->iface);
785
}
786

    
787
static void
788
bfd_stop_neighbor(struct bfd_proto *p, struct bfd_neighbor *n)
789
{
790
  if (n->neigh)
791
    n->neigh->data = NULL;
792
  n->neigh = NULL;
793

    
794
  rfree(n->req);
795
  n->req = NULL;
796
}
797

    
798
static inline int
799
bfd_same_neighbor(struct bfd_neighbor *x, struct bfd_neighbor *y)
800
{
801
  return ipa_equal(x->addr, y->addr) && ipa_equal(x->local, y->local) &&
802
    (x->iface == y->iface) && (x->multihop == y->multihop);
803
}
804

    
805
static void
806
bfd_reconfigure_neighbors(struct bfd_proto *p, struct bfd_config *new)
807
{
808
  struct bfd_config *old = (struct bfd_config *) (p->p.cf);
809
  struct bfd_neighbor *on, *nn;
810

    
811
  WALK_LIST(on, old->neigh_list)
812
  {
813
    WALK_LIST(nn, new->neigh_list)
814
      if (bfd_same_neighbor(nn, on))
815
      {
816
        nn->neigh = on->neigh;
817
        if (nn->neigh)
818
          nn->neigh->data = nn;
819

    
820
        nn->req = on->req;
821
        nn->active = 1;
822
        return;
823
      }
824

    
825
    bfd_stop_neighbor(p, on);
826
  }
827

    
828
  WALK_LIST(nn, new->neigh_list)
829
    if (!nn->active)
830
      bfd_start_neighbor(p, nn);
831
}
832

    
833

    
834
/*
835
 *        BFD notify socket
836
 */
837

    
838
/* This core notify code should be replaced after main loop transition to birdloop */
839

    
840
int pipe(int pipefd[2]);
841
void pipe_drain(int fd);
842
void pipe_kick(int fd);
843

    
844
static int
845
bfd_notify_hook(sock *sk, int len)
846
{
847
  struct bfd_proto *p = sk->data;
848
  struct bfd_session *s;
849
  list tmp_list;
850
  u8 state, diag;
851
  node *n, *nn;
852

    
853
  pipe_drain(sk->fd);
854

    
855
  bfd_lock_sessions(p);
856
  init_list(&tmp_list);
857
  add_tail_list(&tmp_list, &p->notify_list);
858
  init_list(&p->notify_list);
859
  bfd_unlock_sessions(p);
860

    
861
  WALK_LIST_FIRST(s, tmp_list)
862
  {
863
    bfd_lock_sessions(p);
864
    rem2_node(&s->n);
865
    state = s->loc_state;
866
    diag = s->loc_diag;
867
    bfd_unlock_sessions(p);
868

    
869
    /* FIXME: convert to btime and move to bfd_session_update_state() */ 
870
    s->last_state_change = now;
871

    
872
    s->notify_running = 1;
873
    WALK_LIST_DELSAFE(n, nn, s->request_list)
874
      bfd_request_notify(SKIP_BACK(struct bfd_request, n, n), state, diag);
875
    s->notify_running = 0;
876

    
877
    /* Remove the session if all requests were removed in notify hooks */
878
    if (EMPTY_LIST(s->request_list))
879
      bfd_remove_session(p, s);
880
  }
881

    
882
  return 0;
883
}
884

    
885
static inline void
886
bfd_notify_kick(struct bfd_proto *p)
887
{
888
  pipe_kick(p->notify_ws->fd);
889
}
890

    
891
static void
892
bfd_noterr_hook(sock *sk, int err)
893
{
894
  struct bfd_proto *p = sk->data;
895
  log(L_ERR "%s: Notify socket error: %m", p->p.name, err);
896
}
897

    
898
static void
899
bfd_notify_init(struct bfd_proto *p)
900
{
901
  int pfds[2];
902
  sock *sk;
903

    
904
  int rv = pipe(pfds);
905
  if (rv < 0)
906
    die("pipe: %m");
907

    
908
  sk = sk_new(p->p.pool);
909
  sk->type = SK_MAGIC;
910
  sk->rx_hook = bfd_notify_hook;
911
  sk->err_hook = bfd_noterr_hook;
912
  sk->fd = pfds[0];
913
  sk->data = p;
914
  if (sk_open(sk) < 0)
915
    die("bfd: sk_open failed");
916
  p->notify_rs = sk;
917

    
918
  /* The write sock is not added to any event loop */
919
  sk = sk_new(p->p.pool);
920
  sk->type = SK_MAGIC;
921
  sk->fd = pfds[1];
922
  sk->data = p;
923
  sk->flags = SKF_THREAD;
924
  if (sk_open(sk) < 0)
925
    die("bfd: sk_open failed");
926
  p->notify_ws = sk;
927
}
928

    
929

    
930
/*
931
 *        BFD protocol glue
932
 */
933

    
934
void
935
bfd_init_all(void)
936
{
937
  init_list(&bfd_proto_list);
938
  init_list(&bfd_wait_list);
939
}
940

    
941
static struct proto *
942
bfd_init(struct proto_config *c)
943
{
944
  struct proto *p = proto_new(c, sizeof(struct bfd_proto));
945

    
946
  p->neigh_notify = bfd_neigh_notify;
947

    
948
  return p;
949
}
950

    
951
static int
952
bfd_start(struct proto *P)
953
{
954
  struct bfd_proto *p = (struct bfd_proto *) P;
955
  struct bfd_config *cf = (struct bfd_config *) (P->cf);
956

    
957
  p->loop = birdloop_new();
958
  p->tpool = rp_new(NULL, "BFD thread root");
959
  pthread_spin_init(&p->lock, PTHREAD_PROCESS_PRIVATE);
960

    
961
  p->session_slab = sl_new(P->pool, sizeof(struct bfd_session));
962
  HASH_INIT(p->session_hash_id, P->pool, 8);
963
  HASH_INIT(p->session_hash_ip, P->pool, 8);
964

    
965
  init_list(&p->iface_list);
966

    
967
  init_list(&p->notify_list);
968
  bfd_notify_init(p);
969

    
970
  add_tail(&bfd_proto_list, &p->bfd_node);
971

    
972
  birdloop_enter(p->loop);
973
  p->rx_1 = bfd_open_rx_sk(p, 0);
974
  p->rx_m = bfd_open_rx_sk(p, 1);
975
  birdloop_leave(p->loop);
976

    
977
  bfd_take_requests(p);
978

    
979
  struct bfd_neighbor *n;
980
  WALK_LIST(n, cf->neigh_list)
981
    bfd_start_neighbor(p, n);
982

    
983
  birdloop_start(p->loop);
984

    
985
  return PS_UP;
986
}
987

    
988

    
989
static int
990
bfd_shutdown(struct proto *P)
991
{
992
  struct bfd_proto *p = (struct bfd_proto *) P;
993
  struct bfd_config *cf = (struct bfd_config *) (P->cf);
994

    
995
  rem_node(&p->bfd_node);
996

    
997
  birdloop_stop(p->loop);
998

    
999
  struct bfd_neighbor *n;
1000
  WALK_LIST(n, cf->neigh_list)
1001
    bfd_stop_neighbor(p, n);
1002

    
1003
  bfd_drop_requests(p);
1004

    
1005
  /* FIXME: This is hack */
1006
  birdloop_enter(p->loop);
1007
  rfree(p->tpool);
1008
  birdloop_leave(p->loop);
1009

    
1010
  birdloop_free(p->loop);
1011

    
1012
  return PS_DOWN;
1013
}
1014

    
1015
static int
1016
bfd_reconfigure(struct proto *P, struct proto_config *c)
1017
{
1018
  struct bfd_proto *p = (struct bfd_proto *) P;
1019
  // struct bfd_config *old = (struct bfd_config *) (P->cf);
1020
  struct bfd_config *new = (struct bfd_config *) c;
1021
  struct bfd_iface *ifa;
1022

    
1023
  birdloop_mask_wakeups(p->loop);
1024

    
1025
  WALK_LIST(ifa, p->iface_list)
1026
    bfd_reconfigure_iface(p, ifa, new);
1027

    
1028
  HASH_WALK(p->session_hash_id, next_id, s)
1029
  {
1030
    if (s->ifa->changed)
1031
      bfd_reconfigure_session(p, s);
1032
  }
1033
  HASH_WALK_END;
1034

    
1035
  bfd_reconfigure_neighbors(p, new);
1036

    
1037
  birdloop_unmask_wakeups(p->loop);
1038

    
1039
  return 1;
1040
}
1041

    
1042
/* Ensure one instance */
1043
struct bfd_config *bfd_cf;
1044

    
1045
static void
1046
bfd_preconfig(struct protocol *P UNUSED, struct config *c UNUSED)
1047
{
1048
  bfd_cf = NULL;
1049
}
1050

    
1051
static void
1052
bfd_copy_config(struct proto_config *dest, struct proto_config *src)
1053
{
1054
  struct bfd_config *d = (struct bfd_config *) dest;
1055
  // struct bfd_config *s = (struct bfd_config *) src;
1056

    
1057
  /* We clean up patt_list and neigh_list, neighbors and ifaces are non-sharable */
1058
  init_list(&d->patt_list);  
1059
  init_list(&d->neigh_list);
1060
}
1061

    
1062
void
1063
bfd_show_sessions(struct proto *P)
1064
{
1065
  byte tbuf[TM_DATETIME_BUFFER_SIZE];
1066
  struct bfd_proto *p = (struct bfd_proto *) P;
1067
  uint state, diag;
1068
  u32 tx_int, timeout;
1069
  const char *ifname;
1070

    
1071
  if (p->p.proto_state != PS_UP)
1072
  {
1073
    cli_msg(-1020, "%s: is not up", p->p.name);
1074
    cli_msg(0, "");
1075
    return;
1076
  }
1077

    
1078
  cli_msg(-1020, "%s:", p->p.name);
1079
  cli_msg(-1020, "%-25s %-10s %-10s %-10s  %8s %8s",
1080
          "IP address", "Interface", "State", "Since", "Interval", "Timeout");
1081

    
1082

    
1083
  HASH_WALK(p->session_hash_id, next_id, s)
1084
  {
1085
    /* FIXME: this is thread-unsafe, but perhaps harmless */
1086
    state = s->loc_state;
1087
    diag = s->loc_diag;
1088
    ifname = (s->ifa && s->ifa->sk->iface) ? s->ifa->sk->iface->name : "---";
1089
    tx_int = s->last_tx ? (MAX(s->des_min_tx_int, s->rem_min_rx_int) TO_MS) : 0;
1090
    timeout = (MAX(s->req_min_rx_int, s->rem_min_tx_int) TO_MS) * s->rem_detect_mult;
1091

    
1092
    state = (state < 4) ? state : 0;
1093
    tm_format_datetime(tbuf, &config->tf_proto, s->last_state_change);
1094

    
1095
    cli_msg(-1020, "%-25I %-10s %-10s %-10s  %3u.%03u  %3u.%03u",
1096
            s->addr, ifname, bfd_state_names[state], tbuf,
1097
            tx_int / 1000, tx_int % 1000, timeout / 1000, timeout % 1000);
1098
  }
1099
  HASH_WALK_END;
1100

    
1101
  cli_msg(0, "");
1102
}
1103

    
1104

    
1105
struct protocol proto_bfd = {
1106
  .name =                "BFD",
1107
  .template =                "bfd%d",
1108
  .init =                bfd_init,
1109
  .start =                bfd_start,
1110
  .shutdown =                bfd_shutdown,
1111
  .reconfigure =        bfd_reconfigure,
1112
  .preconfig =                 bfd_preconfig,
1113
  .copy_config =        bfd_copy_config,
1114
};