summaryrefslogtreecommitdiffstats
path: root/proto/rip/rip.c
blob: f9a4483536ddf571cb89dbfa89d8bcf7191bd44c (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
/*
 *	Rest in pieces - RIP protocol
 *
 *	Copyright (c) 1998, 1999 Pavel Machek <pavel@ucw.cz>
 *
 *	Can be freely distributed and used under the terms of the GNU GPL.
 *
 	FIXME: IpV6 support: packet size
	FIXME: (nonurgent) IpV6 support: receive "route using" blocks
	FIXME: (nonurgent) IpV6 support: generate "nexthop" blocks
		next hops are only advisory, and they are pretty ugly in IpV6.
		I suggest just forgetting about them.

	FIXME (nonurgent): fold rip_connection into rip_interface?

	FIXME: (nonurgent) allow bigger frequencies than 1 regular update in 6 seconds (?)
	FIXME: propagation of metric=infinity into main routing table may or may not be good idea.

 */

/**
 * DOC: Routing information protocol
 *
 * Rip is pretty simple protocol so half of this code is interface
 * with core. We maintain our own linklist of &rip_entry - it serves
 * as our small routing table. Within rip_tx(), this list is
 * walked, and packet is generated using rip_tx_prepare(). This gets
 * tricky because we may need to send more than one packet to one
 * destination. Struct &rip_connection is used to hold info such as how
 * many of &rip_entry ies we already send, and is also used to protect
 * from two concurrent sends to one destination. Each &rip_interface has
 * at most one &rip_connection.
 *
 * We are not going to honour requests for sending part of
 * routing table. That would need to turn split horizon off,
 * etc.  
 *
 * Triggered updates. RFC says: when triggered update was sent, don't send
 * new one for something between 1 and 5 seconds (and send one
 * after that). We do something else: once in 5 second
 * we look for any changed routes and broadcast them.
 */


#define LOCAL_DEBUG

#include "nest/bird.h"
#include "nest/iface.h"
#include "nest/protocol.h"
#include "nest/route.h"
#include "lib/socket.h"
#include "lib/resource.h"
#include "lib/lists.h"
#include "lib/timer.h"
#include "lib/string.h"

#include "rip.h"

#define P ((struct rip_proto *) p)
#define P_CF ((struct rip_proto_config *)p->cf)
#define E ((struct rip_entry *) e)

#define TRACE(level, msg, args...) do { if (p->debug & level) { log(L_TRACE "%s: " msg, p->name , ## args); } } while(0)

static struct rip_interface *new_iface(struct proto *p, struct iface *new, unsigned long flags, struct iface_patt *patt);

#define P_NAME p->name

/*
 * Output processing
 */

static void
rip_tx_err( sock *s, int err )
{
  struct rip_connection *c = s->data;
  struct proto *p = c->proto;
  log( L_ERR "Unexpected error at rip transmit: %M", err );
}

static int
rip_tx_prepare(struct proto *p, ip_addr daddr, struct rip_block *b, struct rip_entry *e, struct rip_interface *rif, int pos )
{
  DBG( "." );
  b->tag     = htons( e->tag );
  b->network = e->n.prefix;
#ifndef IPV6
  b->family  = htons( 2 ); /* AF_INET */
  b->netmask = ipa_mkmask( e->n.pxlen );
  ipa_hton( b->netmask );

  if (neigh_connected_to(p, &e->nexthop, rif->iface))
    b->nexthop = e->nexthop;
  else
    b->nexthop = IPA_NONE;
  ipa_hton( b->nexthop );
#else
  b->pxlen = e->n.pxlen;
#endif
  b->metric  = htonl( e->metric );
  if (neigh_connected_to(p, &e->whotoldme, rif->iface)) {
    DBG( "(split horizon)" );
    b->metric = htonl( P_CF->infinity );
  }
  ipa_hton( b->network );

  return pos+1;
}

static void
rip_tx( sock *s )
{
  struct rip_interface *rif = s->data;
  struct rip_connection *c = rif->busy;
  struct proto *p = c->proto;
  struct rip_packet *packet = (void *) s->tbuf;
  int i, packetlen;
  int maxi, nullupdate = 1;

  DBG( "Sending to %I\n", s->daddr );
  do {

    if (c->done)
      goto done;

    DBG( "Preparing packet to send: " );

    packet->heading.command = RIPCMD_RESPONSE;
    packet->heading.version = RIP_V2;
    packet->heading.unused  = 0;

    i = !!P_CF->authtype;
#ifndef IPV6
    maxi = ((P_CF->authtype == AT_MD5) ? PACKET_MD5_MAX : PACKET_MAX);
#else
    maxi = 5; /* We need to have at least reserve of one at end of packet */
#endif
    
    FIB_ITERATE_START(&P->rtable, &c->iter, z) {
      struct rip_entry *e = (struct rip_entry *) z;

      if (!rif->triggered || (!(e->updated < now-5))) {
	nullupdate = 0;
	i = rip_tx_prepare( p, s->daddr, packet->block + i, e, rif, i );
	if (i >= maxi) {
	  FIB_ITERATE_PUT(&c->iter, z);
	  goto break_loop;
	}
      }
    } FIB_ITERATE_END(z);
    c->done = 1;

  break_loop:

    packetlen = rip_outgoing_authentication(p, (void *) &packet->block[0], packet, i);

    DBG( ", sending %d blocks, ", i );
    if (nullupdate) {
      DBG( "not sending NULL update\n" );
      c->done = 1;
      goto done;
    }
    if (ipa_nonzero(c->daddr))
      i = sk_send_to( s, packetlen, c->daddr, c->dport );
    else
      i = sk_send( s, packetlen );

    DBG( "it wants more\n" );
  
  } while (i>0);
  
  if (i<0) rip_tx_err( s, i );
  DBG( "blocked\n" );
  return;

done:
  DBG( "Looks like I'm" );
  c->rif->busy = NULL;
  rem_node(NODE c);
  mb_free(c);
  DBG( " done\n" );
  return;
}

static void
rip_sendto( struct proto *p, ip_addr daddr, int dport, struct rip_interface *rif )
{
  struct iface *iface = rif->iface;
  struct rip_connection *c;
  static int num = 0;

  if (rif->busy) {
    log (L_WARN "Interface %s is much too slow, dropping request", iface->name);
    return;
  }
  c = mb_alloc( p->pool, sizeof( struct rip_connection ));
  rif->busy = c;
  
  c->addr = daddr;
  c->proto = p;
  c->num = num++;
  c->rif = rif;

  c->dport = dport;
  c->daddr = daddr;
  if (c->rif->sock->data != rif)
    bug("not enough send magic");
#if 0
  if (sk_open(c->send)<0) {
    log( L_ERR "Could not open socket for data send to %I:%d on %s", daddr, dport, rif->iface->name );
    return;
  }
#endif

  c->done = 0;
  fit_init( &c->iter, &P->rtable );
  add_head( &P->connections, NODE c );
  TRACE(D_PACKETS, "Sending my routing table to %I:%d on %s\n", daddr, dport, rif->iface->name );

  rip_tx(c->rif->sock);
}

static struct rip_interface*
find_interface(struct proto *p, struct iface *what)
{
  struct rip_interface *i;

  WALK_LIST (i, P->interfaces)
    if (i->iface == what)
      return i;
  return NULL;
}

/*
 * Input processing
 */

/* Let main routing table know about our new entry */
static void
advertise_entry( struct proto *p, struct rip_block *b, ip_addr whotoldme )
{
  rta *a, A;
  rte *r;
  net *n;
  neighbor *neighbor;
  struct rip_interface *rif;
  int pxlen;

  bzero(&A, sizeof(A));
  A.proto = p;
  A.source = RTS_RIP;
  A.scope = SCOPE_UNIVERSE;
  A.cast = RTC_UNICAST;
  A.dest = RTD_ROUTER;
  A.flags = 0;
#ifndef IPV6
  A.gw = ipa_nonzero(b->nexthop) ? b->nexthop : whotoldme;
  pxlen = ipa_mklen(b->netmask);
#else
  A.gw = whotoldme; /* FIXME: next hop is in other packet for v6 */
  pxlen = b->pxlen;
#endif
  A.from = whotoldme;

  /* No need to look if destination looks valid - ie not net 0 or 127 -- core will do for us. */

  neighbor = neigh_find( p, &A.gw, 0 );
  if (!neighbor) {
    log( L_REMOTE "%I asked me to route %I/%d using not-neighbor %I.", A.from, b->network, pxlen, A.gw );
    return;
  }

  A.iface = neighbor->iface;
  if (!(rif = neighbor->data)) {
    rif = neighbor->data = find_interface(p, A.iface);
  }
  if (!rif) {
    bug("Route packet using unknown interface? No.");
    return;
  }
    
  /* set to: interface of nexthop */
  a = rta_lookup(&A);
  if (pxlen==-1)  {
    log( L_REMOTE "%I gave me invalid pxlen/netmask for %I.", A.from, b->network );
    return;
  }
  n = net_get( p->table, b->network, pxlen );
  r = rte_get_temp(a);
  r->u.rip.metric = ntohl(b->metric) + rif->patt->metric;
  if (r->u.rip.metric > P_CF->infinity) r->u.rip.metric = P_CF->infinity;
  r->u.rip.tag = ntohl(b->tag);
  r->net = n;
  r->pflags = 0; /* Here go my flags */
  rte_update( p->table, n, p, r );
  DBG( "done\n" );
}

static void
process_block( struct proto *p, struct rip_block *block, ip_addr whotoldme )
{
  int metric = ntohl( block->metric );
  ip_addr network = block->network;

  CHK_MAGIC;
  TRACE(D_ROUTES, "block: %I tells me: %I/??? available, metric %d... ", whotoldme, network, metric );
  if ((!metric) || (metric > P_CF->infinity)) {
#ifdef IPV6 /* Someone is sedning us nexthop and we are ignoring it */
    if (metric == 0xff)
      { debug( "IpV6 nexthop ignored" ); return; }
#endif
    log( L_WARN "Got metric %d from %I", metric, whotoldme );
    return;
  }

  advertise_entry( p, block, whotoldme );
}

#define BAD( x ) { log( L_REMOTE "%s: " x, P_NAME ); return 1; }

static int
rip_process_packet( struct proto *p, struct rip_packet *packet, int num, ip_addr whotoldme, int port )
{
  int i;
  int native_class = 0, authenticated = 0;

  switch( packet->heading.version ) {
  case RIP_V1: DBG( "Rip1: " ); break;
  case RIP_V2: DBG( "Rip2: " ); break;
  default: BAD( "Unknown version" );
  }

  switch( packet->heading.command ) {
  case RIPCMD_REQUEST: DBG( "Asked to send my routing table\n" ); 
	  if (P_CF->honour == HO_NEVER) {
	    log( L_REMOTE "They asked me to send routing table, but I was told not to do it" );
	    return 0;
	  }
	  if ((P_CF->honour == HO_NEIGHBOUR) && (!neigh_find( p, &whotoldme, 0 ))) {
	    log( L_REMOTE "They asked me to send routing table, but he is not my neighbour" );
	    return 0;
	  }
    	  rip_sendto( p, whotoldme, port, HEAD(P->interfaces) ); /* no broadcast */
          break;
  case RIPCMD_RESPONSE: DBG( "*** Rtable from %I\n", whotoldme ); 
          if (port != P_CF->port) {
	    log( L_REMOTE "%I send me routing info from port %d", whotoldme, port );
#if 0
	    return 0;
#else
	    log( L_REMOTE "...ignoring" );
#endif
	  }

	  if (!neigh_find( p, &whotoldme, 0 )) {
	    log( L_REMOTE "%I send me routing info but he is not my neighbour", whotoldme );
#if 0
	    return 0;
#else
	    log( L_REMOTE "...ignoring" );
#endif
	  }

          for (i=0; i<num; i++) {
	    struct rip_block *block = &packet->block[i];
#ifndef IPV6
	    /* Authentication is not defined for v6 */
	    if (block->family == 0xffff) {
	      if (i)
		continue;	/* md5 tail has this family */
	      if (rip_incoming_authentication(p, (void *) block, packet, num, whotoldme))
		BAD( "Authentication failed" );
	      authenticated = 1;
	      continue;
	    }
#endif
	    if ((!authenticated) && (P_CF->authtype != AT_NONE))
	      BAD( "Packet is not authenticated and it should be" );
	    ipa_ntoh( block->network );
#ifndef IPV6
	    ipa_ntoh( block->netmask );
	    ipa_ntoh( block->nexthop );
	    if (packet->heading.version == RIP_V1)	/* FIXME (nonurgent): switch to disable this? */
	      block->netmask = ipa_class_mask(block->network);
#endif
	    process_block( p, block, whotoldme );
	  }
          break;
  case RIPCMD_TRACEON:
  case RIPCMD_TRACEOFF: BAD( "I was asked for traceon/traceoff" );
  case 5: BAD( "Some Sun extension around here" );
  default: BAD( "Unknown command" );
  }

  return 0;
}

static int
rip_rx(sock *s, int size)
{
  struct rip_interface *i = s->data;
  struct proto *p = i->proto;
  int num;

  CHK_MAGIC;
  DBG( "RIP: message came: %d bytes\n", size );
  size -= sizeof( struct rip_packet_heading );
  if (size < 0) BAD( "Too small packet" );
  if (size % sizeof( struct rip_block )) BAD( "Odd sized packet" );
  num = size / sizeof( struct rip_block );
  if (num>PACKET_MAX) BAD( "Too many blocks" );

  rip_process_packet( p, (struct rip_packet *) s->rbuf, num, s->faddr, s->fport );
  return 1;
}

/*
 * Interface to rest of bird
 */

static void
rip_dump_entry( struct rip_entry *e )
{
  debug( "%I told me %d/%d ago: to %I/%d go via %I, metric %d ", 
  e->whotoldme, e->updated-now, e->changed-now, e->n.prefix, e->n.pxlen, e->nexthop, e->metric );
  if (e->flags & RIP_F_EXTERNAL) debug( "[external]" );
  debug( "\n" );
}

static void
rip_timer(timer *t)
{
  struct proto *p = t->data;
  struct rip_entry *e, *et;

  CHK_MAGIC;
  DBG( "RIP: tick tock\n" );
  
  WALK_LIST_DELSAFE( e, et, P->garbage ) {
    rte *rte;
    rte = SKIP_BACK( struct rte, u.rip.garbage, e );
    DBG( "Garbage: " ); rte_dump( rte );

    if (now - rte->u.rip.lastmodX > P_CF->timeout_time) {
      TRACE(D_EVENTS, "RIP: entry is too old: %I", rte->net->n.prefix );
      e->metric = P_CF->infinity;
    }

    if (now - rte->u.rip.lastmodX > P_CF->garbage_time) {
      TRACE(D_EVENTS, "RIP: entry is much too old: %I", rte->net->n.prefix );
      rte_discard(p->table, rte);
    }
  }

  DBG( "RIP: Broadcasting routing tables\n" );
  {
    struct rip_interface *rif;
    P->tx_count ++;

    WALK_LIST( rif, P->interfaces ) {
      struct iface *iface = rif->iface;

      if (!iface) continue;
      if (rif->patt->mode & IM_QUIET) continue;
      if (!(iface->flags & IF_UP)) continue;

      rif->triggered = (P->tx_count % 6);
      rip_sendto( p, IPA_NONE, 0, rif );
    }
  }

  DBG( "RIP: tick tock done\n" );
}

/**
 * rip_start - initialize instance of rip
 */
static int
rip_start(struct proto *p)
{
  struct rip_interface *rif;
  DBG( "RIP: starting instance...\n" );

  P->magic = RIP_MAGIC;
  fib_init( &P->rtable, p->pool, sizeof( struct rip_entry ), 0, NULL );
  init_list( &P->connections );
  init_list( &P->garbage );
  init_list( &P->interfaces );
  P->timer = tm_new( p->pool );
  P->timer->data = p;
  P->timer->randomize = 5;
  P->timer->recurrent = (P_CF->period / 6)+1; 
  P->timer->hook = rip_timer;
  tm_start( P->timer, 5 );
  rif = new_iface(p, NULL, 0, NULL);	/* Initialize dummy interface */
  add_head( &P->interfaces, NODE rif );
  CHK_MAGIC;

  rip_init_instance(p);

  DBG( "RIP: ...done\n");
  return PS_UP;
}

static struct proto *
rip_init(struct proto_config *cfg)
{
  struct proto *p = proto_new(cfg, sizeof(struct rip_proto));

  return p;
}

static void
rip_dump(struct proto *p)
{
  int i;
  node *w, *e;
  struct rip_interface *rif;
  i = 0;

  CHK_MAGIC;
  WALK_LIST( w, P->connections ) {
    struct rip_connection *n = (void *) w;
    debug( "RIP: connection #%d: %I\n", n->num, n->addr );
  }
  i = 0;
  FIB_WALK( &P->rtable, e ) {
    debug( "RIP: entry #%d: ", i++ );
    rip_dump_entry( E );
  } FIB_WALK_END;
  i = 0;
  WALK_LIST( rif, P->interfaces ) {
    debug( "RIP: interface #%d: %s, %I, busy = %x\n", i++, rif->iface?rif->iface->name:"(dummy)", rif->sock->daddr, rif->busy );
  }
}

static void
rip_get_route_info(rte *rte, byte *buf)
{
  buf += bsprintf(buf, " (%d/%d)", rte->pref, rte->u.rip.metric );
  bsprintf(buf, " t%04x", rte->u.rip.tag );
}

static int
rip_want_this_if(struct rip_interface *iface)
{
  return 1;
}

static void
kill_iface(struct proto *p, struct rip_interface *i)
{
  DBG( "RIP: Interface %s disappeared\n", i->iface->name);
  rfree(i->sock);
  mb_free(i);
}

/**
 * new_iface - actually create struct interface and start listening to it
 * @new: interface to be created or %NULL if we are creating magic
 * socket. Magic socket is used for listening, and is also used for
 * sending requested responses. 
 */
static struct rip_interface *
new_iface(struct proto *p, struct iface *new, unsigned long flags, struct iface_patt *patt )
{
  struct rip_interface *rif;

  rif = mb_allocz(p->pool, sizeof( struct rip_interface ));
  rif->iface = new;
  rif->proto = p;
  rif->busy = NULL;
  rif->patt = (struct rip_patt *) patt;

  if (rif->patt)
    rif->multicast = (!(rif->patt->mode & IM_BROADCAST)) && (flags & IF_MULTICAST);
  /* lookup multicasts over unnumbered links - no: rip is not defined over unnumbered links */

  if (rif->multicast)
    DBG( "Doing multicasts!\n" );

  rif->sock = sk_new( p->pool );
  rif->sock->type = rif->multicast?SK_UDP_MC:SK_UDP;
  rif->sock->sport = P_CF->port;
  rif->sock->rx_hook = rip_rx;
  rif->sock->data = rif;
  rif->sock->rbsize = 10240;
  rif->sock->iface = new;		/* Automagically works for dummy interface */
  rif->sock->tbuf = mb_alloc( p->pool, sizeof( struct rip_packet ));
  rif->sock->tx_hook = rip_tx;
  rif->sock->err_hook = rip_tx_err;
  rif->sock->daddr = IPA_NONE;
  rif->sock->dport = P_CF->port;
  if (new)
    rif->sock->ttl = 1;
  else
    rif->sock->ttl = 30;
  rif->sock->tos = IP_PREC_INTERNET_CONTROL;

  if (new) {
    if (new->addr->flags & IA_UNNUMBERED)
      log( L_WARN "%s: rip is not defined over unnumbered links", P_NAME );
    if (rif->multicast) {
#ifndef IPV6
      rif->sock->daddr = ipa_from_u32(0xe0000009);
      rif->sock->saddr = ipa_from_u32(0xe0000009);
#else
      ip_pton("FF02::9", &rif->sock->daddr);
      ip_pton("FF02::9", &rif->sock->saddr);
#endif
    } else
      rif->sock->daddr = new->addr->brd;
  }

  if (!ipa_nonzero(rif->sock->daddr)) {
    log( L_WARN "%s: interface %s is too strange for me", P_NAME, rif->iface ? rif->iface->name : "(dummy)" );
  } else
    if (!(rif->patt->mode & IM_NOLISTEN))
      if (sk_open(rif->sock)<0) {
	log( L_ERR "%s: could not listen on %s", P_NAME, rif->iface ? rif->iface->name : "(dummy)" );
	/* Don't try to transmit into this one? Well, why not? This should not happen, anyway :-) */
      }

  TRACE(D_EVENTS, "%s: listening on %s, port %d, mode %s (%I)", P_NAME, rif->iface ? rif->iface->name : "(dummy)", P_CF->port, rif->multicast ? "multicast" : "broadcast", rif->sock->daddr );
  
  return rif;
}

static void
rip_real_if_add(struct object_lock *lock)
{
  struct iface *iface = lock->iface;
  struct proto *p = lock->data;
  struct rip_interface *rif;
  struct iface_patt *k = iface_patt_match(&P_CF->iface_list, iface);

  if (!k)
    bug("This can not happen! It existed few seconds ago!" );
  DBG("adding interface %s\n", iface->name );
  rif = new_iface(p, iface, iface->flags, k);
  add_head( &P->interfaces, NODE rif );
  rif->lock = lock;
}

static void
rip_if_notify(struct proto *p, unsigned c, struct iface *iface)
{
  DBG( "RIP: if notify\n" );
  if (iface->flags & IF_IGNORE)
    return;
  if (c & IF_CHANGE_DOWN) {
    struct rip_interface *i;
    i = find_interface(p, iface);
    if (i) {
      rem_node(NODE i);
      kill_iface(p, i);
      rfree(i->lock);
    }
  }
  if (c & IF_CHANGE_UP) {
    struct rip_interface *rif;
    struct iface_patt *k = iface_patt_match(&P_CF->iface_list, iface);
    struct object_lock *lock;

    if (!k) return; /* We are not interested in this interface */
    
    lock = olock_new( p->pool );
#ifndef IPV6
    lock->addr = ipa_from_u32(0xe0000009);	/* This is okay: we
						   may actually use
						   other address, but
						   we do not want two
						   rips at one time,
						   anyway. */
#else
    ip_pton("FF02::9", &lock->addr);
#endif
    lock->port = P_CF->port;
    lock->iface = iface;
    lock->hook = rip_real_if_add;
    lock->data = p;
    lock->type = OBJLOCK_UDP;
    olock_acquire(lock);
  }
}

static struct ea_list *
rip_gen_attrs(struct proto *p, struct linpool *pool, int metric, u16 tag)
{
  struct ea_list *l = lp_alloc(pool, sizeof(struct ea_list) + 2*sizeof(eattr));

  l->next = NULL;
  l->flags = EALF_SORTED;
  l->count = 2;
  l->attrs[0].id = EA_RIP_TAG;
  l->attrs[0].flags = 0;
  l->attrs[0].type = EAF_TYPE_INT | EAF_TEMP;
  l->attrs[0].u.data = tag;
  l->attrs[1].id = EA_RIP_METRIC;
  l->attrs[1].flags = 0;
  l->attrs[1].type = EAF_TYPE_INT | EAF_TEMP;
  l->attrs[1].u.data = metric;
  return l;
}

static int
rip_import_control(struct proto *p, struct rte **rt, struct ea_list **attrs, struct linpool *pool)
{
  if ((*rt)->attrs->proto == p)	/* My own must not be touched */
    return 1;

  if ((*rt)->attrs->source != RTS_RIP) {
    struct ea_list *new = rip_gen_attrs(p, pool, 1, 0);
    new->next = *attrs;
    *attrs = new;
  }
  return 0;
}

static struct ea_list *
rip_make_tmp_attrs(struct rte *rt, struct linpool *pool)
{
  struct proto *p = rt->attrs->proto;
  return rip_gen_attrs(p, pool, rt->u.rip.metric, rt->u.rip.tag);
}

static void 
rip_store_tmp_attrs(struct rte *rt, struct ea_list *attrs)
{
  struct proto *p = rt->attrs->proto;

  rt->u.rip.tag = ea_find(attrs, EA_RIP_TAG)->u.data;
  rt->u.rip.metric = ea_find(attrs, EA_RIP_METRIC)->u.data;
}

static void
rip_rt_notify(struct proto *p, struct network *net, struct rte *new, struct rte *old, struct ea_list *attrs)
{
  CHK_MAGIC;

  if (old) {
    struct rip_entry *e = fib_find( &P->rtable, &net->n.prefix, net->n.pxlen );
    if (!e)
      log( L_BUG "Deleting nonexistent entry?!" );
    fib_delete( &P->rtable, e );
  }

  if (new) {
    struct rip_entry *e;
    if (fib_find( &P->rtable, &net->n.prefix, net->n.pxlen ))
      log( L_BUG "Inserting entry which is already there?" );
    e = fib_get( &P->rtable, &net->n.prefix, net->n.pxlen );

    e->nexthop = new->attrs->gw;
    e->metric = 0;
    e->whotoldme = IPA_NONE;

    e->tag = ea_find(attrs, EA_RIP_TAG)->u.data;
    e->metric = ea_find(attrs, EA_RIP_METRIC)->u.data;
    if (e->metric > P_CF->infinity)
      e->metric = P_CF->infinity;

    if (new->attrs->proto == p)
      e->whotoldme = new->attrs->from;

    if (!e->metric)	/* That's okay: this way user can set his own value for external
			   routes in rip. */
      e->metric = 5;
    e->updated = e->changed = now;
    e->flags = 0;
  }
}

static int
rip_rte_better(struct rte *new, struct rte *old)
{
  struct proto *p = new->attrs->proto;

  if (ipa_equal(old->attrs->from, new->attrs->from))
    return 1;

  if (old->u.rip.metric < new->u.rip.metric)
    return 0;

  if (old->u.rip.metric > new->u.rip.metric)
    return 1;

  if ((old->u.rip.metric < 16) && (new->u.rip.metric == P_CF->infinity)) {
    new->u.rip.lastmodX = now - P_CF->timeout_time;	/* Check this: if new metric is 16, act as it was timed out */
  }

  if (old->attrs->proto == new->attrs->proto)		/* This does not make much sense for different protocols */
    if ((old->u.rip.metric == new->u.rip.metric) &&
	((now - old->u.rip.lastmodX) > (P_CF->timeout_time / 2)))
      return 1;

  return 0;
}

static void
rip_rte_insert(net *net, rte *rte)
{
  struct proto *p = rte->attrs->proto;
  rte->u.rip.lastmodX = now;
  add_head( &P->garbage, &rte->u.rip.garbage );
}

static void
rip_rte_remove(net *net, rte *rte)
{
  struct proto *p = rte->attrs->proto;
  rem_node( &rte->u.rip.garbage );
}

void
rip_init_instance(struct proto *p)
{
  p->preference = DEF_PREF_RIP;
  p->if_notify = rip_if_notify;
  p->rt_notify = rip_rt_notify;
  p->import_control = rip_import_control;
  p->make_tmp_attrs = rip_make_tmp_attrs;
  p->store_tmp_attrs = rip_store_tmp_attrs;
  p->rte_better = rip_rte_better;
  p->rte_insert = rip_rte_insert;
  p->rte_remove = rip_rte_remove;
}

void
rip_init_config(struct rip_proto_config *c)
{
  init_list(&c->iface_list);
  c->infinity	= 16;
  c->port	= 520;
  c->period	= 30;
  c->garbage_time = 120+180;
  c->timeout_time = 120;
  c->passwords	= NULL;
  c->authtype	= AT_NONE;
}

static void
rip_preconfig(struct protocol *x, struct config *c)
{
  DBG( "RIP: preconfig\n" );
}

static int
rip_get_attr(eattr *a, byte *buf)
{
  unsigned int i = EA_ID(a->id);
  struct attr_desc *d;

  switch (a->id) {
  case EA_RIP_METRIC: buf += bsprintf( buf, "metric: %d", a->u.data ); return GA_FULL;
  case EA_RIP_TAG:    buf += bsprintf( buf, "tag: %d", a->u.data );    return GA_FULL;
  default: return GA_UNKNOWN;
  }
}

struct protocol proto_rip = {
  name: "RIP",
  template: "rip%d",
  attr_class: EAP_RIP,
  preconfig: rip_preconfig,
  get_route_info: rip_get_route_info,
  get_attr: rip_get_attr,

  init: rip_init,
  dump: rip_dump,
  start: rip_start,
};