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1
/*
2
 *        BIRD -- Routing Information Protocol (RIP)
3
 *
4
 *        (c) 1998--1999 Pavel Machek <pavel@ucw.cz>
5
 *        (c) 2004--2013 Ondrej Filip <feela@network.cz>
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 *        (c) 2009--2015 Ondrej Zajicek <santiago@crfreenet.org>
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 *        (c) 2009--2015 CZ.NIC z.s.p.o.
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 *
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 *        Can be freely distributed and used under the terms of the GNU GPL.
10
 */
11

    
12
/**
13
 * DOC: Routing Information Protocol (RIP)
14
 *
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 * The RIP protocol is implemented in two files: |rip.c| containing the protocol
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 * logic, route management and the protocol glue with BIRD core, and |packets.c|
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 * handling RIP packet processing, RX, TX and protocol sockets.
18
 *
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 * Each instance of RIP is described by a structure &rip_proto, which contains
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 * an internal RIP routing table, a list of protocol interfaces and the main
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 * timer responsible for RIP routing table cleanup.
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 *
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 * RIP internal routing table contains incoming and outgoing routes. For each
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 * network (represented by structure &rip_entry) there is one outgoing route
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 * stored directly in &rip_entry and an one-way linked list of incoming routes
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 * (structures &rip_rte). The list contains incoming routes from different RIP
27
 * neighbors, but only routes with the lowest metric are stored (i.e., all
28
 * stored incoming routes have the same metric).
29
 *
30
 * Note that RIP itself does not select outgoing route, that is done by the core
31
 * routing table. When a new incoming route is received, it is propagated to the
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 * RIP table by rip_update_rte() and possibly stored in the list of incoming
33
 * routes. Then the change may be propagated to the core by rip_announce_rte().
34
 * The core selects the best route and propagate it to RIP by rip_rt_notify(),
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 * which updates outgoing route part of &rip_entry and possibly triggers route
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 * propagation by rip_trigger_update().
37
 *
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 * RIP interfaces are represented by structures &rip_iface. A RIP interface
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 * contains a per-interface socket, a list of associated neighbors, interface
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 * configuration, and state information related to scheduled interface events
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 * and running update sessions. RIP interfaces are added and removed based on
42
 * core interface notifications.
43
 *
44
 * There are two RIP interface events - regular updates and triggered updates.
45
 * Both are managed from the RIP interface timer (rip_iface_timer()). Regular
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 * updates are called at fixed interval and propagate the whole routing table,
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 * while triggered updates are scheduled by rip_trigger_update() due to some
48
 * routing table change and propagate only the routes modified since the time
49
 * they were scheduled. There are also unicast-destined requested updates, but
50
 * these are sent directly as a reaction to received RIP request message. The
51
 * update session is started by rip_send_table(). There may be at most one
52
 * active update session per interface, as the associated state (including the
53
 * fib iterator) is stored directly in &rip_iface structure.
54
 *
55
 * RIP neighbors are represented by structures &rip_neighbor. Compared to
56
 * neighbor handling in other routing protocols, RIP does not have explicit
57
 * neighbor discovery and adjacency maintenance, which makes the &rip_neighbor
58
 * related code a bit peculiar. RIP neighbors are interlinked with core neighbor
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 * structures (&neighbor) and use core neighbor notifications to ensure that RIP
60
 * neighbors are timely removed. RIP neighbors are added based on received route
61
 * notifications and removed based on core neighbor and RIP interface events.
62
 *
63
 * RIP neighbors are linked by RIP routes and use counter to track the number of
64
 * associated routes, but when these RIP routes timeout, associated RIP neighbor
65
 * is still alive (with zero counter). When RIP neighbor is removed but still
66
 * has some associated routes, it is not freed, just changed to detached state
67
 * (core neighbors and RIP ifaces are unlinked), then during the main timer
68
 * cleanup phase the associated routes are removed and the &rip_neighbor
69
 * structure is finally freed.
70
 *
71
 * Supported standards:
72
 * - RFC 1058 - RIPv1
73
 * - RFC 2453 - RIPv2
74
 * - RFC 2080 - RIPng
75
 * - RFC 4822 - RIP cryptographic authentication
76
 */
77

    
78
#include <stdlib.h>
79
#include "rip.h"
80

    
81

    
82
static inline void rip_lock_neighbor(struct rip_neighbor *n);
83
static inline void rip_unlock_neighbor(struct rip_neighbor *n);
84
static inline int rip_iface_link_up(struct rip_iface *ifa);
85
static inline void rip_kick_timer(struct rip_proto *p);
86
static inline void rip_iface_kick_timer(struct rip_iface *ifa);
87
static void rip_iface_timer(timer *timer);
88
static void rip_trigger_update(struct rip_proto *p);
89

    
90

    
91
/*
92
 *        RIP routes
93
 */
94

    
95
static struct rip_rte *
96
rip_add_rte(struct rip_proto *p, struct rip_rte **rp, struct rip_rte *src)
97
{
98
  struct rip_rte *rt = sl_alloc(p->rte_slab);
99

    
100
  memcpy(rt, src, sizeof(struct rip_rte));
101
  rt->next = *rp;
102
  *rp = rt;
103

    
104
  rip_lock_neighbor(rt->from);
105

    
106
  return rt;
107
}
108

    
109
static inline void
110
rip_remove_rte(struct rip_proto *p, struct rip_rte **rp)
111
{
112
  struct rip_rte *rt = *rp;
113

    
114
  rip_unlock_neighbor(rt->from);
115

    
116
  *rp = rt->next;
117
  sl_free(p->rte_slab, rt);
118
}
119

    
120
static inline int rip_same_rte(struct rip_rte *a, struct rip_rte *b)
121
{ return a->metric == b->metric && a->tag == b->tag && ipa_equal(a->next_hop, b->next_hop); }
122

    
123
static inline int rip_valid_rte(struct rip_rte *rt)
124
{ return rt->from->ifa != NULL; }
125

    
126
/**
127
 * rip_announce_rte - announce route from RIP routing table to the core
128
 * @p: RIP instance
129
 * @en: related network
130
 *
131
 * The function takes a list of incoming routes from @en, prepare appropriate
132
 * &rte for the core and propagate it by rte_update().
133
 */
134
static void
135
rip_announce_rte(struct rip_proto *p, struct rip_entry *en)
136
{
137
  struct rip_rte *rt = en->routes;
138

    
139
  /* Find first valid rte */
140
  while (rt && !rip_valid_rte(rt))
141
    rt = rt->next;
142

    
143
  if (rt)
144
  {
145
    /* Update */
146
    rta a0 = {
147
      .src = p->p.main_source,
148
      .source = RTS_RIP,
149
      .scope = SCOPE_UNIVERSE,
150
      .dest = RTD_UNICAST,
151
    };
152

    
153
    u8 rt_metric = rt->metric;
154
    u16 rt_tag = rt->tag;
155

    
156
    if (p->ecmp)
157
    {
158
      /* ECMP route */
159
      struct nexthop *nhs = NULL;
160
      int num = 0;
161

    
162
      for (rt = en->routes; rt && (num < p->ecmp); rt = rt->next)
163
      {
164
        if (!rip_valid_rte(rt))
165
            continue;
166

    
167
        struct nexthop *nh = allocz(sizeof(struct nexthop));
168

    
169
        nh->gw = rt->next_hop;
170
        nh->iface = rt->from->nbr->iface;
171
        nh->weight = rt->from->ifa->cf->ecmp_weight;
172

    
173
        nexthop_insert(&nhs, nh);
174
        num++;
175

    
176
        if (rt->tag != rt_tag)
177
          rt_tag = 0;
178
      }
179

    
180
      a0.nh = *nhs;
181
    }
182
    else
183
    {
184
      /* Unipath route */
185
      a0.from = rt->from->nbr->addr;
186
      a0.nh.gw = rt->next_hop;
187
      a0.nh.iface = rt->from->nbr->iface;
188
    }
189

    
190
    rta *a = rta_lookup(&a0);
191
    rte *e = rte_get_temp(a);
192

    
193
    e->u.rip.from = a0.nh.iface;
194
    e->u.rip.metric = rt_metric;
195
    e->u.rip.tag = rt_tag;
196

    
197
    e->pflags = 0;
198

    
199
    rte_update(&p->p, en->n.addr, e);
200
  }
201
  else
202
  {
203
    /* Withdraw */
204
    rte_update(&p->p, en->n.addr, NULL);
205
  }
206
}
207

    
208
/**
209
 * rip_update_rte - enter a route update to RIP routing table
210
 * @p: RIP instance
211
 * @addr: network address
212
 * @new: a &rip_rte representing the new route
213
 *
214
 * The function is called by the RIP packet processing code whenever it receives
215
 * a reachable route. The appropriate routing table entry is found and the list
216
 * of incoming routes is updated. Eventually, the change is also propagated to
217
 * the core by rip_announce_rte(). Note that for unreachable routes,
218
 * rip_withdraw_rte() should be called instead of rip_update_rte().
219
 */
220
void
221
rip_update_rte(struct rip_proto *p, net_addr *n, struct rip_rte *new)
222
{
223
  struct rip_entry *en = fib_get(&p->rtable, n);
224
  struct rip_rte *rt, **rp;
225
  int changed = 0;
226

    
227
  /* If the new route is better, remove all current routes */
228
  if (en->routes && new->metric < en->routes->metric)
229
    while (en->routes)
230
      rip_remove_rte(p, &en->routes);
231

    
232
  /* Find the old route (also set rp for later) */
233
  for (rp = &en->routes; rt = *rp; rp = &rt->next)
234
    if (rt->from == new->from)
235
    {
236
      if (rip_same_rte(rt, new))
237
      {
238
        rt->expires = new->expires;
239
        return;
240
      }
241

    
242
      /* Remove the old route */
243
      rip_remove_rte(p, rp);
244
      changed = 1;
245
      break;
246
    }
247

    
248
  /* If the new route is optimal, add it to the list */
249
  if (!en->routes || new->metric == en->routes->metric)
250
  {
251
    rt = rip_add_rte(p, rp, new);
252
    changed = 1;
253
  }
254

    
255
  /* Announce change if on relevant position (the first or any for ECMP) */
256
  if (changed && (rp == &en->routes || p->ecmp))
257
    rip_announce_rte(p, en);
258
}
259

    
260
/**
261
 * rip_withdraw_rte - enter a route withdraw to RIP routing table
262
 * @p: RIP instance
263
 * @addr: network address
264
 * @from: a &rip_neighbor propagating the withdraw
265
 *
266
 * The function is called by the RIP packet processing code whenever it receives
267
 * an unreachable route. The incoming route for given network from nbr @from is
268
 * removed. Eventually, the change is also propagated by rip_announce_rte().
269
 */
270
void
271
rip_withdraw_rte(struct rip_proto *p, net_addr *n, struct rip_neighbor *from)
272
{
273
  struct rip_entry *en = fib_find(&p->rtable, n);
274
  struct rip_rte *rt, **rp;
275

    
276
  if (!en)
277
    return;
278

    
279
  /* Find the old route */
280
  for (rp = &en->routes; rt = *rp; rp = &rt->next)
281
    if (rt->from == from)
282
      break;
283

    
284
  if (!rt)
285
    return;
286

    
287
  /* Remove the old route */
288
  rip_remove_rte(p, rp);
289

    
290
  /* Announce change if on relevant position */
291
  if (rp == &en->routes || p->ecmp)
292
    rip_announce_rte(p, en);
293
}
294

    
295
/*
296
 * rip_rt_notify - core tells us about new route, so store
297
 * it into our data structures.
298
 */
299
static void
300
rip_rt_notify(struct proto *P, struct channel *ch UNUSED, struct network *net, struct rte *new,
301
              struct rte *old UNUSED, struct ea_list *attrs)
302
{
303
  struct rip_proto *p = (struct rip_proto *) P;
304
  struct rip_entry *en;
305
  int old_metric;
306

    
307
  if (new)
308
  {
309
    /* Update */
310
    u32 rt_metric = ea_get_int(attrs, EA_RIP_METRIC, 1);
311
    u32 rt_tag = ea_get_int(attrs, EA_RIP_TAG, 0);
312

    
313
    if (rt_metric > p->infinity)
314
    {
315
      log(L_WARN "%s: Invalid rip_metric value %u for route %N",
316
          p->p.name, rt_metric, net->n.addr);
317
      rt_metric = p->infinity;
318
    }
319

    
320
    if (rt_tag > 0xffff)
321
    {
322
      log(L_WARN "%s: Invalid rip_tag value %u for route %N",
323
          p->p.name, rt_tag, net->n.addr);
324
      rt_metric = p->infinity;
325
      rt_tag = 0;
326
    }
327

    
328
    /*
329
     * Note that we accept exported routes with infinity metric (this could
330
     * happen if rip_metric is modified in filters). Such entry has infinity
331
     * metric but is RIP_ENTRY_VALID and therefore is not subject to garbage
332
     * collection.
333
     */
334

    
335
    en = fib_get(&p->rtable, net->n.addr);
336

    
337
    old_metric = en->valid ? en->metric : -1;
338

    
339
    en->valid = RIP_ENTRY_VALID;
340
    en->metric = rt_metric;
341
    en->tag = rt_tag;
342
    en->from = (new->attrs->src->proto == P) ? new->u.rip.from : NULL;
343
    en->iface = new->attrs->nh.iface;
344
    en->next_hop = new->attrs->nh.gw;
345
  }
346
  else
347
  {
348
    /* Withdraw */
349
    en = fib_find(&p->rtable, net->n.addr);
350

    
351
    if (!en || en->valid != RIP_ENTRY_VALID)
352
      return;
353

    
354
    old_metric = en->metric;
355

    
356
    en->valid = RIP_ENTRY_STALE;
357
    en->metric = p->infinity;
358
    en->tag = 0;
359
    en->from = NULL;
360
    en->iface = NULL;
361
    en->next_hop = IPA_NONE;
362
  }
363

    
364
  /* Activate triggered updates */
365
  if (en->metric != old_metric)
366
  {
367
    en->changed = now;
368
    rip_trigger_update(p);
369
  }
370
}
371

    
372

    
373
/*
374
 *        RIP neighbors
375
 */
376

    
377
struct rip_neighbor *
378
rip_get_neighbor(struct rip_proto *p, ip_addr *a, struct rip_iface *ifa)
379
{
380
  neighbor *nbr = neigh_find2(&p->p, a, ifa->iface, 0);
381

    
382
  if (!nbr || (nbr->scope == SCOPE_HOST) || !rip_iface_link_up(ifa))
383
    return NULL;
384

    
385
  if (nbr->data)
386
    return nbr->data;
387

    
388
  TRACE(D_EVENTS, "New neighbor %I on %s", *a, ifa->iface->name);
389

    
390
  struct rip_neighbor *n = mb_allocz(p->p.pool, sizeof(struct rip_neighbor));
391
  n->ifa = ifa;
392
  n->nbr = nbr;
393
  nbr->data = n;
394
  n->csn = nbr->aux;
395

    
396
  add_tail(&ifa->neigh_list, NODE n);
397

    
398
  return n;
399
}
400

    
401
static void
402
rip_remove_neighbor(struct rip_proto *p, struct rip_neighbor *n)
403
{
404
  neighbor *nbr = n->nbr;
405

    
406
  TRACE(D_EVENTS, "Removing neighbor %I on %s", nbr->addr, nbr->iface->name);
407

    
408
  rem_node(NODE n);
409
  n->ifa = NULL;
410
  n->nbr = NULL;
411
  nbr->data = NULL;
412
  nbr->aux = n->csn;
413

    
414
  rfree(n->bfd_req);
415
  n->bfd_req = NULL;
416
  n->last_seen = 0;
417

    
418
  if (!n->uc)
419
    mb_free(n);
420

    
421
  /* Related routes are removed in rip_timer() */
422
  rip_kick_timer(p);
423
}
424

    
425
static inline void
426
rip_lock_neighbor(struct rip_neighbor *n)
427
{
428
  n->uc++;
429
}
430

    
431
static inline void
432
rip_unlock_neighbor(struct rip_neighbor *n)
433
{
434
  n->uc--;
435

    
436
  if (!n->nbr && !n->uc)
437
    mb_free(n);
438
}
439

    
440
static void
441
rip_neigh_notify(struct neighbor *nbr)
442
{
443
  struct rip_proto *p = (struct rip_proto *) nbr->proto;
444
  struct rip_neighbor *n = nbr->data;
445

    
446
  if (!n)
447
    return;
448

    
449
  /*
450
   * We assume that rip_neigh_notify() is called before rip_if_notify() for
451
   * IF_CHANGE_DOWN and therefore n->ifa is still valid. We have no such
452
   * ordering assumption for IF_CHANGE_LINK, so we test link state of the
453
   * underlying iface instead of just rip_iface state.
454
   */
455
  if ((nbr->scope <= 0) || !rip_iface_link_up(n->ifa))
456
    rip_remove_neighbor(p, n);
457
}
458

    
459
static void
460
rip_bfd_notify(struct bfd_request *req)
461
{
462
  struct rip_neighbor *n = req->data;
463
  struct rip_proto *p = n->ifa->rip;
464

    
465
  if (req->down)
466
  {
467
    TRACE(D_EVENTS, "BFD session down for nbr %I on %s",
468
          n->nbr->addr, n->ifa->iface->name);
469
    rip_remove_neighbor(p, n);
470
  }
471
}
472

    
473
void
474
rip_update_bfd(struct rip_proto *p, struct rip_neighbor *n)
475
{
476
  int use_bfd = n->ifa->cf->bfd && n->last_seen;
477

    
478
  if (use_bfd && !n->bfd_req)
479
  {
480
    /*
481
     * For RIPv2, use the same address as rip_open_socket(). For RIPng, neighbor
482
     * should contain an address from the same prefix, thus also link-local. It
483
     * may cause problems if two link-local addresses are assigned to one iface.
484
     */
485
    ip_addr saddr = rip_is_v2(p) ? n->ifa->sk->saddr : n->nbr->ifa->ip;
486
    n->bfd_req = bfd_request_session(p->p.pool, n->nbr->addr, saddr,
487
                                     n->nbr->iface, rip_bfd_notify, n);
488
  }
489

    
490
  if (!use_bfd && n->bfd_req)
491
  {
492
    rfree(n->bfd_req);
493
    n->bfd_req = NULL;
494
  }
495
}
496

    
497

    
498
/*
499
 *        RIP interfaces
500
 */
501

    
502
static void
503
rip_iface_start(struct rip_iface *ifa)
504
{
505
  struct rip_proto *p = ifa->rip;
506

    
507
  TRACE(D_EVENTS, "Starting interface %s", ifa->iface->name);
508

    
509
  ifa->next_regular = now + (random() % ifa->cf->update_time) + 1;
510
  ifa->next_triggered = now;        /* Available immediately */
511
  ifa->want_triggered = 1;        /* All routes in triggered update */
512
  tm_start(ifa->timer, 1);        /* Or 100 ms */
513
  ifa->up = 1;
514

    
515
  if (!ifa->cf->passive)
516
    rip_send_request(ifa->rip, ifa);
517
}
518

    
519
static void
520
rip_iface_stop(struct rip_iface *ifa)
521
{
522
  struct rip_proto *p = ifa->rip;
523
  struct rip_neighbor *n;
524

    
525
  TRACE(D_EVENTS, "Stopping interface %s", ifa->iface->name);
526

    
527
  rip_reset_tx_session(p, ifa);
528

    
529
  WALK_LIST_FIRST(n, ifa->neigh_list)
530
    rip_remove_neighbor(p, n);
531

    
532
  tm_stop(ifa->timer);
533
  ifa->up = 0;
534
}
535

    
536
static inline int
537
rip_iface_link_up(struct rip_iface *ifa)
538
{
539
  return !ifa->cf->check_link || (ifa->iface->flags & IF_LINK_UP);
540
}
541

    
542
static void
543
rip_iface_update_state(struct rip_iface *ifa)
544
{
545
  int up = ifa->sk && rip_iface_link_up(ifa);
546

    
547
  if (up == ifa->up)
548
    return;
549

    
550
  if (up)
551
    rip_iface_start(ifa);
552
  else
553
    rip_iface_stop(ifa);
554
}
555

    
556
static void
557
rip_iface_update_buffers(struct rip_iface *ifa)
558
{
559
  if (!ifa->sk)
560
    return;
561

    
562
  uint rbsize = ifa->cf->rx_buffer ?: ifa->iface->mtu;
563
  uint tbsize = ifa->cf->tx_length ?: ifa->iface->mtu;
564
  rbsize = MAX(rbsize, tbsize);
565

    
566
  sk_set_rbsize(ifa->sk, rbsize);
567
  sk_set_tbsize(ifa->sk, tbsize);
568

    
569
  uint headers = (rip_is_v2(ifa->rip) ? IP4_HEADER_LENGTH : IP6_HEADER_LENGTH) + UDP_HEADER_LENGTH;
570
  ifa->tx_plen = tbsize - headers;
571

    
572
  if (ifa->cf->auth_type == RIP_AUTH_CRYPTO)
573
    ifa->tx_plen -= RIP_AUTH_TAIL_LENGTH + max_mac_length(ifa->cf->passwords);
574
}
575

    
576
static inline void
577
rip_iface_update_bfd(struct rip_iface *ifa)
578
{
579
  struct rip_proto *p = ifa->rip;
580
  struct rip_neighbor *n;
581

    
582
  WALK_LIST(n, ifa->neigh_list)
583
    rip_update_bfd(p, n);
584
}
585

    
586

    
587
static void
588
rip_iface_locked(struct object_lock *lock)
589
{
590
  struct rip_iface *ifa = lock->data;
591
  struct rip_proto *p = ifa->rip;
592

    
593
  if (!rip_open_socket(ifa))
594
  {
595
    log(L_ERR "%s: Cannot open socket for %s", p->p.name, ifa->iface->name);
596
    return;
597
  }
598

    
599
  rip_iface_update_buffers(ifa);
600
  rip_iface_update_state(ifa);
601
}
602

    
603

    
604
static struct rip_iface *
605
rip_find_iface(struct rip_proto *p, struct iface *what)
606
{
607
  struct rip_iface *ifa;
608

    
609
  WALK_LIST(ifa, p->iface_list)
610
    if (ifa->iface == what)
611
      return ifa;
612

    
613
  return NULL;
614
}
615

    
616
static void
617
rip_add_iface(struct rip_proto *p, struct iface *iface, struct rip_iface_config *ic)
618
{
619
  struct rip_iface *ifa;
620

    
621
  TRACE(D_EVENTS, "Adding interface %s", iface->name);
622

    
623
  ifa = mb_allocz(p->p.pool, sizeof(struct rip_iface));
624
  ifa->rip = p;
625
  ifa->iface = iface;
626
  ifa->cf = ic;
627

    
628
  if (ipa_nonzero(ic->address))
629
    ifa->addr = ic->address;
630
  else if (ic->mode == RIP_IM_MULTICAST)
631
    ifa->addr = rip_is_v2(p) ? IP4_RIP_ROUTERS : IP6_RIP_ROUTERS;
632
  else /* Broadcast */
633
    ifa->addr = iface->addr->brd;
634

    
635
  init_list(&ifa->neigh_list);
636

    
637
  add_tail(&p->iface_list, NODE ifa);
638

    
639
  ifa->timer = tm_new_set(p->p.pool, rip_iface_timer, ifa, 0, 0);
640

    
641
  struct object_lock *lock = olock_new(p->p.pool);
642
  lock->type = OBJLOCK_UDP;
643
  lock->port = ic->port;
644
  lock->iface = iface;
645
  lock->data = ifa;
646
  lock->hook = rip_iface_locked;
647
  ifa->lock = lock;
648

    
649
  olock_acquire(lock);
650
}
651

    
652
static void
653
rip_remove_iface(struct rip_proto *p, struct rip_iface *ifa)
654
{
655
  rip_iface_stop(ifa);
656

    
657
  TRACE(D_EVENTS, "Removing interface %s", ifa->iface->name);
658

    
659
  rem_node(NODE ifa);
660

    
661
  rfree(ifa->sk);
662
  rfree(ifa->lock);
663
  rfree(ifa->timer);
664

    
665
  mb_free(ifa);
666
}
667

    
668
static int
669
rip_reconfigure_iface(struct rip_proto *p, struct rip_iface *ifa, struct rip_iface_config *new)
670
{
671
  struct rip_iface_config *old = ifa->cf;
672

    
673
  /* Change of these options would require to reset the iface socket */
674
  if ((new->mode != old->mode) ||
675
      (new->port != old->port) ||
676
      (new->tx_tos != old->tx_tos) ||
677
      (new->tx_priority != old->tx_priority) ||
678
      (new->ttl_security != old->ttl_security))
679
    return 0;
680

    
681
  TRACE(D_EVENTS, "Reconfiguring interface %s", ifa->iface->name);
682

    
683
  ifa->cf = new;
684

    
685
  rip_iface_update_buffers(ifa);
686

    
687
  if (ifa->next_regular > (now + new->update_time))
688
    ifa->next_regular = now + (random() % new->update_time) + 1;
689

    
690
  if (new->check_link != old->check_link)
691
    rip_iface_update_state(ifa);
692

    
693
  if (new->bfd != old->bfd)
694
    rip_iface_update_bfd(ifa);
695

    
696
  if (ifa->up)
697
    rip_iface_kick_timer(ifa);
698

    
699
  return 1;
700
}
701

    
702
static void
703
rip_reconfigure_ifaces(struct rip_proto *p, struct rip_config *cf)
704
{
705
  struct iface *iface;
706

    
707
  WALK_LIST(iface, iface_list)
708
  {
709
    if (! (iface->flags & IF_UP))
710
      continue;
711

    
712
    struct rip_iface *ifa = rip_find_iface(p, iface);
713
    struct rip_iface_config *ic = (void *) iface_patt_find(&cf->patt_list, iface, NULL);
714

    
715
    if (ifa && ic)
716
    {
717
      if (rip_reconfigure_iface(p, ifa, ic))
718
        continue;
719

    
720
      /* Hard restart */
721
      log(L_INFO "%s: Restarting interface %s", p->p.name, ifa->iface->name);
722
      rip_remove_iface(p, ifa);
723
      rip_add_iface(p, iface, ic);
724
    }
725

    
726
    if (ifa && !ic)
727
      rip_remove_iface(p, ifa);
728

    
729
    if (!ifa && ic)
730
      rip_add_iface(p, iface, ic);
731
  }
732
}
733

    
734
static void
735
rip_if_notify(struct proto *P, unsigned flags, struct iface *iface)
736
{
737
  struct rip_proto *p = (void *) P;
738
  struct rip_config *cf = (void *) P->cf;
739

    
740
  if (iface->flags & IF_IGNORE)
741
    return;
742

    
743
  if (flags & IF_CHANGE_UP)
744
  {
745
    struct rip_iface_config *ic = (void *) iface_patt_find(&cf->patt_list, iface, NULL);
746

    
747
    if (ic)
748
      rip_add_iface(p, iface, ic);
749

    
750
    return;
751
  }
752

    
753
  struct rip_iface *ifa = rip_find_iface(p, iface);
754

    
755
  if (!ifa)
756
    return;
757

    
758
  if (flags & IF_CHANGE_DOWN)
759
  {
760
    rip_remove_iface(p, ifa);
761
    return;
762
  }
763

    
764
  if (flags & IF_CHANGE_MTU)
765
    rip_iface_update_buffers(ifa);
766

    
767
  if (flags & IF_CHANGE_LINK)
768
    rip_iface_update_state(ifa);
769
}
770

    
771

    
772
/*
773
 *        RIP timer events
774
 */
775

    
776
/**
777
 * rip_timer - RIP main timer hook
778
 * @t: timer
779
 *
780
 * The RIP main timer is responsible for routing table maintenance. Invalid or
781
 * expired routes (&rip_rte) are removed and garbage collection of stale routing
782
 * table entries (&rip_entry) is done. Changes are propagated to core tables,
783
 * route reload is also done here. Note that garbage collection uses a maximal
784
 * GC time, while interfaces maintain an illusion of per-interface GC times in
785
 * rip_send_response().
786
 *
787
 * Keeping incoming routes and the selected outgoing route are two independent
788
 * functions, therefore after garbage collection some entries now considered
789
 * invalid (RIP_ENTRY_DUMMY) still may have non-empty list of incoming routes,
790
 * while some valid entries (representing an outgoing route) may have that list
791
 * empty.
792
 *
793
 * The main timer is not scheduled periodically but it uses the time of the
794
 * current next event and the minimal interval of any possible event to compute
795
 * the time of the next run.
796
 */
797
static void
798
rip_timer(timer *t)
799
{
800
  struct rip_proto *p = t->data;
801
  struct rip_config *cf = (void *) (p->p.cf);
802
  struct rip_iface *ifa;
803
  struct rip_neighbor *n, *nn;
804
  struct fib_iterator fit;
805
  bird_clock_t next = now + MIN(cf->min_timeout_time, cf->max_garbage_time);
806
  bird_clock_t expires = 0;
807

    
808
  TRACE(D_EVENTS, "Main timer fired");
809

    
810
  FIB_ITERATE_INIT(&fit, &p->rtable);
811

    
812
  loop:
813
  FIB_ITERATE_START(&p->rtable, &fit, struct rip_entry, en)
814
  {
815
    struct rip_rte *rt, **rp;
816
    int changed = 0;
817

    
818
    /* Checking received routes for timeout and for dead neighbors */
819
    for (rp = &en->routes; rt = *rp; /* rp = &rt->next */)
820
    {
821
      if (!rip_valid_rte(rt) || (rt->expires <= now))
822
      {
823
        rip_remove_rte(p, rp);
824
        changed = 1;
825
        continue;
826
      }
827

    
828
      next = MIN(next, rt->expires);
829
      rp = &rt->next;
830
    }
831

    
832
    /* Propagating eventual change */
833
    if (changed || p->rt_reload)
834
    {
835
      /*
836
       * We have to restart the iteration because there may be a cascade of
837
       * synchronous events rip_announce_rte() -> nest table change ->
838
       * rip_rt_notify() -> p->rtable change, invalidating hidden variables.
839
       */
840

    
841
      FIB_ITERATE_PUT_NEXT(&fit, &p->rtable);
842
      rip_announce_rte(p, en);
843
      goto loop;
844
    }
845

    
846
    /* Checking stale entries for garbage collection timeout */
847
    if (en->valid == RIP_ENTRY_STALE)
848
    {
849
      expires = en->changed + cf->max_garbage_time;
850

    
851
      if (expires <= now)
852
      {
853
        // TRACE(D_EVENTS, "entry is too old: %N", en->n.addr);
854
        en->valid = 0;
855
      }
856
      else
857
        next = MIN(next, expires);
858
    }
859

    
860
    /* Remove empty nodes */
861
    if (!en->valid && !en->routes)
862
    {
863
      FIB_ITERATE_PUT(&fit);
864
      fib_delete(&p->rtable, en);
865
      goto loop;
866
    }
867
  }
868
  FIB_ITERATE_END;
869

    
870
  p->rt_reload = 0;
871

    
872
  /* Handling neighbor expiration */
873
  WALK_LIST(ifa, p->iface_list)
874
    WALK_LIST_DELSAFE(n, nn, ifa->neigh_list)
875
      if (n->last_seen)
876
      {
877
        expires = n->last_seen + n->ifa->cf->timeout_time;
878

    
879
        if (expires <= now)
880
          rip_remove_neighbor(p, n);
881
        else
882
          next = MIN(next, expires);
883
      }
884

    
885
  tm_start(p->timer, MAX(next - now, 1));
886
}
887

    
888
static inline void
889
rip_kick_timer(struct rip_proto *p)
890
{
891
  if (p->timer->expires > (now + 1))
892
    tm_start(p->timer, 1);        /* Or 100 ms */
893
}
894

    
895
/**
896
 * rip_iface_timer - RIP interface timer hook
897
 * @t: timer
898
 *
899
 * RIP interface timers are responsible for scheduling both regular and
900
 * triggered updates. Fixed, delay-independent period is used for regular
901
 * updates, while minimal separating interval is enforced for triggered updates.
902
 * The function also ensures that a new update is not started when the old one
903
 * is still running.
904
 */
905
static void
906
rip_iface_timer(timer *t)
907
{
908
  struct rip_iface *ifa = t->data;
909
  struct rip_proto *p = ifa->rip;
910
  bird_clock_t period = ifa->cf->update_time;
911

    
912
  if (ifa->cf->passive)
913
    return;
914

    
915
  TRACE(D_EVENTS, "Interface timer fired for %s", ifa->iface->name);
916

    
917
  if (ifa->tx_active)
918
  {
919
    if (now < (ifa->next_regular + period))
920
      { tm_start(ifa->timer, 1); return; }
921

    
922
    /* We are too late, reset is done by rip_send_table() */
923
    log(L_WARN "%s: Too slow update on %s, resetting", p->p.name, ifa->iface->name);
924
  }
925

    
926
  if (now >= ifa->next_regular)
927
  {
928
    /* Send regular update, set timer for next period (or following one if necessay) */
929
    TRACE(D_EVENTS, "Sending regular updates for %s", ifa->iface->name);
930
    rip_send_table(p, ifa, ifa->addr, 0);
931
    ifa->next_regular += period * (1 + ((now - ifa->next_regular) / period));
932
    ifa->want_triggered = 0;
933
    p->triggered = 0;
934
  }
935
  else if (ifa->want_triggered && (now >= ifa->next_triggered))
936
  {
937
    /* Send triggered update, enforce interval between triggered updates */
938
    TRACE(D_EVENTS, "Sending triggered updates for %s", ifa->iface->name);
939
    rip_send_table(p, ifa, ifa->addr, ifa->want_triggered);
940
    ifa->next_triggered = now + MIN(5, period / 2 + 1);
941
    ifa->want_triggered = 0;
942
    p->triggered = 0;
943
  }
944

    
945
  tm_start(ifa->timer, ifa->want_triggered ? 1 : (ifa->next_regular - now));
946
}
947

    
948
static inline void
949
rip_iface_kick_timer(struct rip_iface *ifa)
950
{
951
  if (ifa->timer->expires > (now + 1))
952
    tm_start(ifa->timer, 1);        /* Or 100 ms */
953
}
954

    
955
static void
956
rip_trigger_update(struct rip_proto *p)
957
{
958
  if (p->triggered)
959
    return;
960

    
961
  struct rip_iface *ifa;
962
  WALK_LIST(ifa, p->iface_list)
963
  {
964
    /* Interface not active */
965
    if (! ifa->up)
966
      continue;
967

    
968
    /* Already scheduled */
969
    if (ifa->want_triggered)
970
      continue;
971

    
972
    TRACE(D_EVENTS, "Scheduling triggered updates for %s", ifa->iface->name);
973
    ifa->want_triggered = now;
974
    rip_iface_kick_timer(ifa);
975
  }
976

    
977
  p->triggered = 1;
978
}
979

    
980

    
981
/*
982
 *        RIP protocol glue
983
 */
984

    
985
static struct ea_list *
986
rip_prepare_attrs(struct linpool *pool, ea_list *next, u8 metric, u16 tag)
987
{
988
  struct ea_list *l = lp_alloc(pool, sizeof(struct ea_list) + 2 * sizeof(eattr));
989

    
990
  l->next = next;
991
  l->flags = EALF_SORTED;
992
  l->count = 2;
993

    
994
  l->attrs[0].id = EA_RIP_METRIC;
995
  l->attrs[0].flags = 0;
996
  l->attrs[0].type = EAF_TYPE_INT | EAF_TEMP;
997
  l->attrs[0].u.data = metric;
998

    
999
  l->attrs[1].id = EA_RIP_TAG;
1000
  l->attrs[1].flags = 0;
1001
  l->attrs[1].type = EAF_TYPE_INT | EAF_TEMP;
1002
  l->attrs[1].u.data = tag;
1003

    
1004
  return l;
1005
}
1006

    
1007
static int
1008
rip_import_control(struct proto *P UNUSED, struct rte **rt, struct ea_list **attrs, struct linpool *pool)
1009
{
1010
  /* Prepare attributes with initial values */
1011
  if ((*rt)->attrs->source != RTS_RIP)
1012
    *attrs = rip_prepare_attrs(pool, *attrs, 1, 0);
1013

    
1014
  return 0;
1015
}
1016

    
1017
static void
1018
rip_reload_routes(struct channel *C)
1019
{
1020
  struct rip_proto *p = (struct rip_proto *) C->proto;
1021

    
1022
  if (p->rt_reload)
1023
    return;
1024

    
1025
  TRACE(D_EVENTS, "Scheduling route reload");
1026
  p->rt_reload = 1;
1027
  rip_kick_timer(p);
1028
}
1029

    
1030
static struct ea_list *
1031
rip_make_tmp_attrs(struct rte *rt, struct linpool *pool)
1032
{
1033
  return rip_prepare_attrs(pool, NULL, rt->u.rip.metric, rt->u.rip.tag);
1034
}
1035

    
1036
static void
1037
rip_store_tmp_attrs(struct rte *rt, struct ea_list *attrs)
1038
{
1039
  rt->u.rip.metric = ea_get_int(attrs, EA_RIP_METRIC, 1);
1040
  rt->u.rip.tag = ea_get_int(attrs, EA_RIP_TAG, 0);
1041
}
1042

    
1043
static int
1044
rip_rte_better(struct rte *new, struct rte *old)
1045
{
1046
  return new->u.rip.metric < old->u.rip.metric;
1047
}
1048

    
1049
static int
1050
rip_rte_same(struct rte *new, struct rte *old)
1051
{
1052
  return ((new->u.rip.metric == old->u.rip.metric) &&
1053
          (new->u.rip.tag == old->u.rip.tag) &&
1054
          (new->u.rip.from == old->u.rip.from));
1055
}
1056

    
1057

    
1058
static void
1059
rip_postconfig(struct proto_config *CF)
1060
{
1061
  // struct rip_config *cf = (void *) CF;
1062

    
1063
  /* Define default channel */
1064
  if (EMPTY_LIST(CF->channels))
1065
    channel_config_new(NULL, CF->net_type, CF);
1066
}
1067

    
1068
static struct proto *
1069
rip_init(struct proto_config *CF)
1070
{
1071
  struct proto *P = proto_new(CF);
1072

    
1073
  P->main_channel = proto_add_channel(P, proto_cf_main_channel(CF));
1074

    
1075
  P->if_notify = rip_if_notify;
1076
  P->rt_notify = rip_rt_notify;
1077
  P->neigh_notify = rip_neigh_notify;
1078
  P->import_control = rip_import_control;
1079
  P->reload_routes = rip_reload_routes;
1080
  P->make_tmp_attrs = rip_make_tmp_attrs;
1081
  P->store_tmp_attrs = rip_store_tmp_attrs;
1082
  P->rte_better = rip_rte_better;
1083
  P->rte_same = rip_rte_same;
1084

    
1085
  return P;
1086
}
1087

    
1088
static int
1089
rip_start(struct proto *P)
1090
{
1091
  struct rip_proto *p = (void *) P;
1092
  struct rip_config *cf = (void *) (P->cf);
1093

    
1094
  init_list(&p->iface_list);
1095
  fib_init(&p->rtable, P->pool, cf->rip2 ? NET_IP4 : NET_IP6,
1096
           sizeof(struct rip_entry), OFFSETOF(struct rip_entry, n), 0, NULL);
1097
  p->rte_slab = sl_new(P->pool, sizeof(struct rip_rte));
1098
  p->timer = tm_new_set(P->pool, rip_timer, p, 0, 0);
1099

    
1100
  p->rip2 = cf->rip2;
1101
  p->ecmp = cf->ecmp;
1102
  p->infinity = cf->infinity;
1103
  p->triggered = 0;
1104

    
1105
  p->log_pkt_tbf = (struct tbf){ .rate = 1, .burst = 5 };
1106
  p->log_rte_tbf = (struct tbf){ .rate = 4, .burst = 20 };
1107

    
1108
  tm_start(p->timer, MIN(cf->min_timeout_time, cf->max_garbage_time));
1109

    
1110
  return PS_UP;
1111
}
1112

    
1113
static int
1114
rip_reconfigure(struct proto *P, struct proto_config *CF)
1115
{
1116
  struct rip_proto *p = (void *) P;
1117
  struct rip_config *new = (void *) CF;
1118
  // struct rip_config *old = (void *) (P->cf);
1119

    
1120
  if (new->rip2 != p->rip2)
1121
    return 0;
1122

    
1123
  if (new->infinity != p->infinity)
1124
    return 0;
1125

    
1126
  if (!proto_configure_channel(P, &P->main_channel, proto_cf_main_channel(CF)))
1127
    return 0;
1128

    
1129
  TRACE(D_EVENTS, "Reconfiguring");
1130

    
1131
  p->p.cf = CF;
1132
  p->ecmp = new->ecmp;
1133
  rip_reconfigure_ifaces(p, new);
1134

    
1135
  p->rt_reload = 1;
1136
  rip_kick_timer(p);
1137

    
1138
  return 1;
1139
}
1140

    
1141
static void
1142
rip_get_route_info(rte *rte, byte *buf, ea_list *attrs UNUSED)
1143
{
1144
  buf += bsprintf(buf, " (%d/%d)", rte->pref, rte->u.rip.metric);
1145

    
1146
  if (rte->u.rip.tag)
1147
    bsprintf(buf, " [%04x]", rte->u.rip.tag);
1148
}
1149

    
1150
static int
1151
rip_get_attr(eattr *a, byte *buf, int buflen UNUSED)
1152
{
1153
  switch (a->id)
1154
  {
1155
  case EA_RIP_METRIC:
1156
    bsprintf(buf, "metric: %d", a->u.data);
1157
    return GA_FULL;
1158

    
1159
  case EA_RIP_TAG:
1160
    bsprintf(buf, "tag: %04x", a->u.data);
1161
    return GA_FULL;
1162

    
1163
  default:
1164
    return GA_UNKNOWN;
1165
  }
1166
}
1167

    
1168
void
1169
rip_show_interfaces(struct proto *P, char *iff)
1170
{
1171
  struct rip_proto *p = (void *) P;
1172
  struct rip_iface *ifa = NULL;
1173
  struct rip_neighbor *n = NULL;
1174

    
1175
  if (p->p.proto_state != PS_UP)
1176
  {
1177
    cli_msg(-1021, "%s: is not up", p->p.name);
1178
    cli_msg(0, "");
1179
    return;
1180
  }
1181

    
1182
  cli_msg(-1021, "%s:", p->p.name);
1183
  cli_msg(-1021, "%-10s %-6s %6s %6s %6s",
1184
          "Interface", "State", "Metric", "Nbrs", "Timer");
1185

    
1186
  WALK_LIST(ifa, p->iface_list)
1187
  {
1188
    if (iff && !patmatch(iff, ifa->iface->name))
1189
      continue;
1190

    
1191
    int nbrs = 0;
1192
    WALK_LIST(n, ifa->neigh_list)
1193
      if (n->last_seen)
1194
        nbrs++;
1195

    
1196
    int timer = MAX(ifa->next_regular - now, 0);
1197
    cli_msg(-1021, "%-10s %-6s %6u %6u %6u",
1198
            ifa->iface->name, (ifa->up ? "Up" : "Down"), ifa->cf->metric, nbrs, timer);
1199
  }
1200

    
1201
  cli_msg(0, "");
1202
}
1203

    
1204
void
1205
rip_show_neighbors(struct proto *P, char *iff)
1206
{
1207
  struct rip_proto *p = (void *) P;
1208
  struct rip_iface *ifa = NULL;
1209
  struct rip_neighbor *n = NULL;
1210

    
1211
  if (p->p.proto_state != PS_UP)
1212
  {
1213
    cli_msg(-1022, "%s: is not up", p->p.name);
1214
    cli_msg(0, "");
1215
    return;
1216
  }
1217

    
1218
  cli_msg(-1022, "%s:", p->p.name);
1219
  cli_msg(-1022, "%-25s %-10s %6s %6s %6s",
1220
          "IP address", "Interface", "Metric", "Routes", "Seen");
1221

    
1222
  WALK_LIST(ifa, p->iface_list)
1223
  {
1224
    if (iff && !patmatch(iff, ifa->iface->name))
1225
      continue;
1226

    
1227
    WALK_LIST(n, ifa->neigh_list)
1228
    {
1229
      if (!n->last_seen)
1230
        continue;
1231

    
1232
      int timer = now - n->last_seen;
1233
      cli_msg(-1022, "%-25I %-10s %6u %6u %6u",
1234
              n->nbr->addr, ifa->iface->name, ifa->cf->metric, n->uc, timer);
1235
    }
1236
  }
1237

    
1238
  cli_msg(0, "");
1239
}
1240

    
1241
static void
1242
rip_dump(struct proto *P)
1243
{
1244
  struct rip_proto *p = (struct rip_proto *) P;
1245
  struct rip_iface *ifa;
1246
  int i;
1247

    
1248
  i = 0;
1249
  FIB_WALK(&p->rtable, struct rip_entry, en)
1250
  {
1251
    debug("RIP: entry #%d: %N via %I dev %s valid %d metric %d age %d s\n",
1252
          i++, en->n.addr, en->next_hop, en->iface->name,
1253
          en->valid, en->metric, now - en->changed);
1254
  }
1255
  FIB_WALK_END;
1256

    
1257
  i = 0;
1258
  WALK_LIST(ifa, p->iface_list)
1259
  {
1260
    debug("RIP: interface #%d: %s, %I, up = %d, busy = %d\n",
1261
          i++, ifa->iface->name, ifa->sk ? ifa->sk->daddr : IPA_NONE,
1262
          ifa->up, ifa->tx_active);
1263
  }
1264
}
1265

    
1266

    
1267
struct protocol proto_rip = {
1268
  .name =                "RIP",
1269
  .template =                "rip%d",
1270
  .attr_class =                EAP_RIP,
1271
  .preference =                DEF_PREF_RIP,
1272
  .channel_mask =        NB_IP,
1273
  .proto_size =                sizeof(struct rip_proto),
1274
  .config_size =        sizeof(struct rip_config),
1275
  .postconfig =                rip_postconfig,
1276
  .init =                rip_init,
1277
  .dump =                rip_dump,
1278
  .start =                rip_start,
1279
  .reconfigure =        rip_reconfigure,
1280
  .get_route_info =        rip_get_route_info,
1281
  .get_attr =                rip_get_attr
1282
};