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iof-bird-daemon / sysdep / linux / netlink / netlink.c @ b6c9d8eb

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1
/*
2
 *        BIRD -- Linux Netlink Interface
3
 *
4
 *        (c) 1999--2000 Martin Mares <mj@ucw.cz>
5
 *
6
 *        Can be freely distributed and used under the terms of the GNU GPL.
7
 */
8

    
9
#include <stdio.h>
10
#include <fcntl.h>
11
#include <net/if.h>
12
#include <sys/socket.h>
13
#include <sys/uio.h>
14
#include <errno.h>
15

    
16
#undef LOCAL_DEBUG
17

    
18
#include "nest/bird.h"
19
#include "nest/route.h"
20
#include "nest/protocol.h"
21
#include "nest/iface.h"
22
#include "lib/timer.h"
23
#include "lib/unix.h"
24
#include "lib/krt.h"
25
#include "lib/socket.h"
26
#include "lib/string.h"
27
#include "conf/conf.h"
28

    
29
#include <asm/types.h>
30
#include <linux/netlink.h>
31
#include <linux/rtnetlink.h>
32

    
33
#ifndef MSG_TRUNC                        /* Hack: Several versions of glibc miss this one :( */
34
#define MSG_TRUNC 0x20
35
#endif
36

    
37
/*
38
 *        Synchronous Netlink interface
39
 */
40

    
41
static int nl_sync_fd = -1;                /* Unix socket for synchronous netlink actions */
42
static u32 nl_sync_seq;                        /* Sequence number of last request sent */
43

    
44
static byte *nl_rx_buffer;                /* Receive buffer */
45
#define NL_RX_SIZE 8192
46

    
47
static struct nlmsghdr *nl_last_hdr;        /* Recently received packet */
48
static unsigned int nl_last_size;
49

    
50
static void
51
nl_open(void)
52
{
53
  if (nl_sync_fd < 0)
54
    {
55
      nl_sync_fd = socket(PF_NETLINK, SOCK_RAW, NETLINK_ROUTE);
56
      if (nl_sync_fd < 0)
57
        die("Unable to open rtnetlink socket: %m");
58
      nl_sync_seq = now;
59
      nl_rx_buffer = xmalloc(NL_RX_SIZE);
60
    }
61
}
62

    
63
static void
64
nl_send(struct nlmsghdr *nh)
65
{
66
  struct sockaddr_nl sa;
67

    
68
  memset(&sa, 0, sizeof(sa));
69
  sa.nl_family = AF_NETLINK;
70
  nh->nlmsg_pid = 0;
71
  nh->nlmsg_seq = ++nl_sync_seq;
72
  if (sendto(nl_sync_fd, nh, nh->nlmsg_len, 0, (struct sockaddr *)&sa, sizeof(sa)) < 0)
73
    die("rtnetlink sendto: %m");
74
  nl_last_hdr = NULL;
75
}
76

    
77
static void
78
nl_request_dump(int cmd)
79
{
80
  struct {
81
    struct nlmsghdr nh;
82
    struct rtgenmsg g;
83
  } req;
84
  req.nh.nlmsg_type = cmd;
85
  req.nh.nlmsg_len = sizeof(req);
86
  req.nh.nlmsg_flags = NLM_F_REQUEST | NLM_F_DUMP;
87
  req.g.rtgen_family = BIRD_PF;
88
  nl_send(&req.nh);
89
}
90

    
91
static struct nlmsghdr *
92
nl_get_reply(void)
93
{
94
  for(;;)
95
    {
96
      if (!nl_last_hdr)
97
        {
98
          struct iovec iov = { nl_rx_buffer, NL_RX_SIZE };
99
          struct sockaddr_nl sa;
100
          struct msghdr m = { (struct sockaddr *) &sa, sizeof(sa), &iov, 1, NULL, 0, 0 };
101
          int x = recvmsg(nl_sync_fd, &m, 0);
102
          if (x < 0)
103
            die("nl_get_reply: %m");
104
          if (sa.nl_pid)                /* It isn't from the kernel */
105
            {
106
              DBG("Non-kernel packet\n");
107
              continue;
108
            }
109
          nl_last_size = x;
110
          nl_last_hdr = (void *) nl_rx_buffer;
111
          if (m.msg_flags & MSG_TRUNC)
112
            bug("nl_get_reply: got truncated reply which should be impossible");
113
        }
114
      if (NLMSG_OK(nl_last_hdr, nl_last_size))
115
        {
116
          struct nlmsghdr *h = nl_last_hdr;
117
          if (h->nlmsg_seq != nl_sync_seq)
118
            {
119
              log(L_WARN "nl_get_reply: Ignoring out of sequence netlink packet (%x != %x)",
120
                  h->nlmsg_seq, nl_sync_seq);
121
              continue;
122
            }
123
          nl_last_hdr = NLMSG_NEXT(h, nl_last_size);
124
          return h;
125
        }
126
      if (nl_last_size)
127
        log(L_WARN "nl_get_reply: Found packet remnant of size %d", nl_last_size);
128
      nl_last_hdr = NULL;
129
    }
130
}
131

    
132
static int
133
nl_error(struct nlmsghdr *h)
134
{
135
  struct nlmsgerr *e;
136
  int ec;
137

    
138
  if (h->nlmsg_len < NLMSG_LENGTH(sizeof(struct nlmsgerr)))
139
    {
140
      log(L_WARN "Netlink: Truncated error message received");
141
      return ENOBUFS;
142
    }
143
  e = (struct nlmsgerr *) NLMSG_DATA(h);
144
  ec = -e->error;
145
  if (ec)
146
    log(L_WARN "Netlink: %s", strerror(ec));
147
  return ec;
148
}
149

    
150
static struct nlmsghdr *
151
nl_get_scan(void)
152
{
153
  struct nlmsghdr *h = nl_get_reply();
154

    
155
  if (h->nlmsg_type == NLMSG_DONE)
156
    return NULL;
157
  if (h->nlmsg_type == NLMSG_ERROR)
158
    {
159
      nl_error(h);
160
      return NULL;
161
    }
162
  return h;
163
}
164

    
165
static int
166
nl_exchange(struct nlmsghdr *pkt)
167
{
168
  struct nlmsghdr *h;
169

    
170
  nl_send(pkt);
171
  for(;;)
172
    {
173
      h = nl_get_reply();
174
      if (h->nlmsg_type == NLMSG_ERROR)
175
        break;
176
      log(L_WARN "nl_exchange: Unexpected reply received");
177
    }
178
  return nl_error(h);
179
}
180

    
181
/*
182
 *        Netlink attributes
183
 */
184

    
185
static int nl_attr_len;
186

    
187
static void *
188
nl_checkin(struct nlmsghdr *h, int lsize)
189
{
190
  nl_attr_len = h->nlmsg_len - NLMSG_LENGTH(lsize);
191
  if (nl_attr_len < 0)
192
    {
193
      log(L_ERR "nl_checkin: underrun by %d bytes", -nl_attr_len);
194
      return NULL;
195
    }
196
  return NLMSG_DATA(h);
197
}
198

    
199
static int
200
nl_parse_attrs(struct rtattr *a, struct rtattr **k, int ksize)
201
{
202
  int max = ksize / sizeof(struct rtattr *);
203
  bzero(k, ksize);
204
  while (RTA_OK(a, nl_attr_len))
205
    {
206
      if (a->rta_type < max)
207
        k[a->rta_type] = a;
208
      a = RTA_NEXT(a, nl_attr_len);
209
    }
210
  if (nl_attr_len)
211
    {
212
      log(L_ERR "nl_parse_attrs: remnant of size %d", nl_attr_len);
213
      return 0;
214
    }
215
  else
216
    return 1;
217
}
218

    
219
static void
220
nl_add_attr_u32(struct nlmsghdr *h, unsigned maxsize, int code, u32 data)
221
{
222
  unsigned len = RTA_LENGTH(4);
223
  struct rtattr *a;
224

    
225
  if (NLMSG_ALIGN(h->nlmsg_len) + len > maxsize)
226
    bug("nl_add_attr32: packet buffer overflow");
227
  a = (struct rtattr *)((char *)h + NLMSG_ALIGN(h->nlmsg_len));
228
  a->rta_type = code;
229
  a->rta_len = len;
230
  memcpy(RTA_DATA(a), &data, 4);
231
  h->nlmsg_len = NLMSG_ALIGN(h->nlmsg_len) + len;
232
}
233

    
234
static void
235
nl_add_attr_ipa(struct nlmsghdr *h, unsigned maxsize, int code, ip_addr ipa)
236
{
237
  unsigned len = RTA_LENGTH(sizeof(ipa));
238
  struct rtattr *a;
239

    
240
  if (NLMSG_ALIGN(h->nlmsg_len) + len > maxsize)
241
    bug("nl_add_attr_ipa: packet buffer overflow");
242
  a = (struct rtattr *)((char *)h + NLMSG_ALIGN(h->nlmsg_len));
243
  a->rta_type = code;
244
  a->rta_len = len;
245
  ipa_hton(ipa);
246
  memcpy(RTA_DATA(a), &ipa, sizeof(ipa));
247
  h->nlmsg_len = NLMSG_ALIGN(h->nlmsg_len) + len;
248
}
249

    
250
/*
251
 *        Scanning of interfaces
252
 */
253

    
254
static void
255
nl_parse_link(struct nlmsghdr *h, int scan)
256
{
257
  struct ifinfomsg *i;
258
  struct rtattr *a[IFLA_STATS+1];
259
  int new = h->nlmsg_type == RTM_NEWLINK;
260
  struct iface f;
261
  struct iface *ifi;
262
  char *name;
263
  u32 mtu;
264
  unsigned int fl;
265

    
266
  if (!(i = nl_checkin(h, sizeof(*i))) || !nl_parse_attrs(IFLA_RTA(i), a, sizeof(a)))
267
    return;
268
  if (!a[IFLA_IFNAME] || RTA_PAYLOAD(a[IFLA_IFNAME]) < 2 ||
269
      !a[IFLA_MTU] || RTA_PAYLOAD(a[IFLA_MTU]) != 4)
270
    {
271
      log(L_ERR "nl_parse_link: Malformed message received");
272
      return;
273
    }
274
  name = RTA_DATA(a[IFLA_IFNAME]);
275
  memcpy(&mtu, RTA_DATA(a[IFLA_MTU]), sizeof(u32));
276

    
277
  ifi = if_find_by_index(i->ifi_index);
278
  if (!new)
279
    {
280
      DBG("KIF: IF%d(%s) goes down\n", i->ifi_index, name);
281
      if (ifi && !scan)
282
        {
283
          memcpy(&f, ifi, sizeof(struct iface));
284
          f.flags |= IF_ADMIN_DOWN;
285
          if_update(&f);
286
        }
287
    }
288
  else
289
    {
290
      DBG("KIF: IF%d(%s) goes up (mtu=%d,flg=%x)\n", i->ifi_index, name, mtu, i->ifi_flags);
291
      if (ifi)
292
        memcpy(&f, ifi, sizeof(f));
293
      else
294
        {
295
          bzero(&f, sizeof(f));
296
          f.index = i->ifi_index;
297
        }
298
      strncpy(f.name, RTA_DATA(a[IFLA_IFNAME]), sizeof(f.name)-1);
299
      f.mtu = mtu;
300
      f.flags = 0;
301
      fl = i->ifi_flags;
302
      if (fl & IFF_UP)
303
        f.flags |= IF_LINK_UP;
304
      if (fl & IFF_LOOPBACK)                /* Loopback */
305
        f.flags |= IF_MULTIACCESS | IF_LOOPBACK | IF_IGNORE;
306
      else if (fl & IFF_POINTOPOINT)        /* PtP */
307
        f.flags |= IF_MULTICAST;
308
      else if (fl & IFF_BROADCAST)        /* Broadcast */
309
        f.flags |= IF_MULTIACCESS | IF_BROADCAST | IF_MULTICAST;
310
      else
311
        f.flags |= IF_MULTIACCESS;        /* NBMA */
312
      if_update(&f);
313
    }
314
}
315

    
316
static void
317
nl_parse_addr(struct nlmsghdr *h)
318
{
319
  struct ifaddrmsg *i;
320
  struct rtattr *a[IFA_ANYCAST+1];
321
  int new = h->nlmsg_type == RTM_NEWADDR;
322
  struct ifa ifa;
323
  struct iface *ifi;
324

    
325
  if (!(i = nl_checkin(h, sizeof(*i))) || !nl_parse_attrs(IFA_RTA(i), a, sizeof(a)))
326
    return;
327
  if (i->ifa_family != BIRD_AF)
328
    return;
329
  if (!a[IFA_ADDRESS] || RTA_PAYLOAD(a[IFA_ADDRESS]) != sizeof(ip_addr)
330
#ifdef IPV6
331
      || a[IFA_LOCAL] && RTA_PAYLOAD(a[IFA_LOCAL]) != sizeof(ip_addr)
332
#else
333
      || !a[IFA_LOCAL] || RTA_PAYLOAD(a[IFA_LOCAL]) != sizeof(ip_addr)
334
      || (a[IFA_BROADCAST] && RTA_PAYLOAD(a[IFA_BROADCAST]) != sizeof(ip_addr))
335
#endif
336
      )
337
    {
338
      log(L_ERR "nl_parse_addr: Malformed message received");
339
      return;
340
    }
341

    
342
#ifdef IPV6
343
  if (i->ifa_scope == RT_SCOPE_LINK)
344
    return;
345
#endif
346

    
347
  ifi = if_find_by_index(i->ifa_index);
348
  if (!ifi)
349
    {
350
      log(L_ERR "KIF: Received address message for unknown interface %d\n", i->ifa_index);
351
      return;
352
    }
353

    
354
  bzero(&ifa, sizeof(ifa));
355
  ifa.iface = ifi;
356
  if (i->ifa_flags & IFA_F_SECONDARY)
357
    ifa.flags |= IA_SECONDARY;
358
  /* IFA_LOCAL can be unset for IPv6 interfaces */
359
  memcpy(&ifa.ip, RTA_DATA(a[IFA_LOCAL] ? : a[IFA_ADDRESS]), sizeof(ifa.ip));
360
  ipa_ntoh(ifa.ip);
361
  ifa.pxlen = i->ifa_prefixlen;
362
  if (i->ifa_prefixlen > BITS_PER_IP_ADDRESS ||
363
      i->ifa_prefixlen == BITS_PER_IP_ADDRESS - 1)
364
    {
365
      log(L_ERR "KIF: Invalid prefix length for interface %s: %d", ifi->name, i->ifa_prefixlen);
366
      new = 0;
367
    }
368
  if (i->ifa_prefixlen == BITS_PER_IP_ADDRESS)
369
    {
370
      ifa.flags |= IA_UNNUMBERED;
371
      memcpy(&ifa.opposite, RTA_DATA(a[IFA_ADDRESS]), sizeof(ifa.opposite));
372
      ipa_ntoh(ifa.opposite);
373
      ifa.prefix = ifa.brd = ifa.opposite;
374
    }
375
  else
376
    {
377
#ifndef IPV6
378
      if (i->ifa_prefixlen == BITS_PER_IP_ADDRESS - 2)
379
        ifa.opposite = ipa_opposite(ifa.ip);
380
      if ((ifi->flags & IF_BROADCAST) && a[IFA_BROADCAST])
381
        {
382
          memcpy(&ifa.brd, RTA_DATA(a[IFA_BROADCAST]), sizeof(ifa.brd));
383
          ipa_ntoh(ifa.brd);
384
        }
385
#endif
386
      ifa.prefix = ipa_and(ifa.ip, ipa_mkmask(ifa.pxlen));
387
    }
388

    
389
  DBG("KIF: IF%d(%s): %s IPA %I, flg %x, net %I/%d, brd %I, opp %I\n",
390
      ifi->index, ifi->name,
391
      new ? "added" : "removed",
392
      ifa.ip, ifa.flags, ifa.prefix, ifa.pxlen, ifa.brd, ifa.opposite);
393
  if (new)
394
    ifa_update(&ifa);
395
  else
396
    ifa_delete(&ifa);
397
}
398

    
399
void
400
krt_if_scan(struct kif_proto *p)
401
{
402
  struct nlmsghdr *h;
403

    
404
  if_start_update();
405

    
406
  nl_request_dump(RTM_GETLINK);
407
  while (h = nl_get_scan())
408
    if (h->nlmsg_type == RTM_NEWLINK || h->nlmsg_type == RTM_DELLINK)
409
      nl_parse_link(h, 1);
410
    else
411
      log(L_DEBUG "nl_scan_ifaces: Unknown packet received (type=%d)", h->nlmsg_type);
412

    
413
  nl_request_dump(RTM_GETADDR);
414
  while (h = nl_get_scan())
415
    if (h->nlmsg_type == RTM_NEWADDR || h->nlmsg_type == RTM_DELADDR)
416
      nl_parse_addr(h);
417
    else
418
      log(L_DEBUG "nl_scan_ifaces: Unknown packet received (type=%d)", h->nlmsg_type);
419

    
420
  if_end_update();
421
}
422

    
423
/*
424
 *        Routes
425
 */
426

    
427
static struct krt_proto *nl_table_map[NL_NUM_TABLES];
428

    
429
int
430
krt_capable(rte *e)
431
{
432
  rta *a = e->attrs;
433

    
434
  if (a->cast != RTC_UNICAST
435
#if 0
436
      && a->cast != RTC_ANYCAST
437
#endif
438
      )
439
    return 0;
440
  if (a->source == RTS_DEVICE)        /* Kernel takes care of device routes itself */
441
    return 0;
442
  switch (a->dest)
443
    {
444
    case RTD_ROUTER:
445
    case RTD_DEVICE:
446
    case RTD_BLACKHOLE:
447
    case RTD_UNREACHABLE:
448
    case RTD_PROHIBIT:
449
      break;
450
    default:
451
      return 0;
452
    }
453
  return 1;
454
}
455

    
456
static void
457
nl_send_route(struct krt_proto *p, rte *e, int new)
458
{
459
  net *net = e->net;
460
  rta *a = e->attrs;
461
  struct {
462
    struct nlmsghdr h;
463
    struct rtmsg r;
464
    char buf[128];
465
  } r;
466

    
467
  DBG("nl_send_route(%I/%d,new=%d)\n", net->n.prefix, net->n.pxlen, new);
468

    
469
  bzero(&r.h, sizeof(r.h));
470
  bzero(&r.r, sizeof(r.r));
471
  r.h.nlmsg_type = new ? RTM_NEWROUTE : RTM_DELROUTE;
472
  r.h.nlmsg_len = NLMSG_LENGTH(sizeof(struct rtmsg));
473
  r.h.nlmsg_flags = NLM_F_REQUEST | NLM_F_ACK | (new ? NLM_F_CREATE|NLM_F_REPLACE : 0);
474

    
475
  r.r.rtm_family = BIRD_AF;
476
  r.r.rtm_dst_len = net->n.pxlen;
477
  r.r.rtm_tos = 0;
478
  r.r.rtm_table = KRT_CF->scan.table_id;
479
  r.r.rtm_protocol = RTPROT_BIRD;
480
  r.r.rtm_scope = RT_SCOPE_UNIVERSE;
481
  nl_add_attr_ipa(&r.h, sizeof(r), RTA_DST, net->n.prefix);
482
  switch (a->dest)
483
    {
484
    case RTD_ROUTER:
485
      r.r.rtm_type = RTN_UNICAST;
486
      nl_add_attr_ipa(&r.h, sizeof(r), RTA_GATEWAY, a->gw);
487
      break;
488
    case RTD_DEVICE:
489
      r.r.rtm_type = RTN_UNICAST;
490
      nl_add_attr_u32(&r.h, sizeof(r), RTA_OIF, a->iface->index);
491
      break;
492
    case RTD_BLACKHOLE:
493
      r.r.rtm_type = RTN_BLACKHOLE;
494
      break;
495
    case RTD_UNREACHABLE:
496
      r.r.rtm_type = RTN_UNREACHABLE;
497
      break;
498
    case RTD_PROHIBIT:
499
      r.r.rtm_type = RTN_PROHIBIT;
500
      break;
501
    default:
502
      bug("krt_capable inconsistent with nl_send_route");
503
    }
504

    
505
  nl_exchange(&r.h);
506
}
507

    
508
void
509
krt_set_notify(struct krt_proto *p, net *n, rte *new, rte *old)
510
{
511
  if (old && new)
512
    {
513
      /*
514
       *  We should check whether priority and TOS is identical as well,
515
       *  but we don't use these and default value is always equal to default value. :-)
516
       */
517
      nl_send_route(p, new, 1);
518
    }
519
  else
520
    {
521
      if (old)
522
        {
523
          if (!old->attrs->iface || (old->attrs->iface->flags & IF_UP))
524
            nl_send_route(p, old, 0);
525
          /* else the kernel has already flushed it */
526
        }
527
      if (new)
528
        nl_send_route(p, new, 1);
529
    }
530
}
531

    
532
struct iface *
533
krt_temp_iface(struct krt_proto *p, unsigned index)
534
{
535
  struct iface *i, *j;
536

    
537
  WALK_LIST(i, p->scan.temp_ifs)
538
    if (i->index == index)
539
      return i;
540
  i = mb_allocz(p->p.pool, sizeof(struct iface));
541
  if (j = if_find_by_index(index))
542
    strcpy(i->name, j->name);
543
  else
544
    strcpy(i->name, "?");
545
  i->index = index;
546
  add_tail(&p->scan.temp_ifs, &i->n);
547
  return i;
548
}
549

    
550
static void
551
nl_parse_route(struct nlmsghdr *h, int scan)
552
{
553
  struct krt_proto *p;
554
  struct rtmsg *i;
555
  struct rtattr *a[RTA_CACHEINFO+1];
556
  int new = h->nlmsg_type == RTM_NEWROUTE;
557
  ip_addr dst;
558
  rta ra;
559
  rte *e;
560
  net *net;
561
  u32 oif;
562
  int src;
563

    
564
  if (!(i = nl_checkin(h, sizeof(*i))) || !nl_parse_attrs(RTM_RTA(i), a, sizeof(a)))
565
    return;
566
  if (i->rtm_family != BIRD_AF)
567
    return;
568
  if ((a[RTA_DST] && RTA_PAYLOAD(a[RTA_DST]) != sizeof(ip_addr)) ||
569
      (a[RTA_OIF] && RTA_PAYLOAD(a[RTA_OIF]) != 4) ||
570
      (a[RTA_PRIORITY] && RTA_PAYLOAD(a[RTA_PRIORITY]) != 4) ||
571
#ifdef IPV6
572
      (a[RTA_IIF] && RTA_PAYLOAD(a[RTA_IIF]) != 4) ||
573
#endif
574
      (a[RTA_GATEWAY] && RTA_PAYLOAD(a[RTA_GATEWAY]) != sizeof(ip_addr)))
575
    {
576
      log(L_ERR "nl_parse_route: Malformed message received");
577
      return;
578
    }
579

    
580
  p = nl_table_map[i->rtm_table];        /* Do we know this table? */
581
  if (!p)
582
    return;
583

    
584
#ifdef IPV6
585
  if (a[RTA_IIF])
586
    {
587
      DBG("KRT: Ignoring route with IIF set\n");
588
      return;
589
    }
590
#else
591
  if (i->rtm_tos != 0)                        /* We don't support TOS */
592
    {
593
      DBG("KRT: Ignoring route with TOS %02x\n", i->rtm_tos);
594
      return;
595
    }
596
#endif
597

    
598
  if (scan && !new)
599
    {
600
      DBG("KRT: Ignoring route deletion\n");
601
      return;
602
    }
603

    
604
  if (a[RTA_DST])
605
    {
606
      memcpy(&dst, RTA_DATA(a[RTA_DST]), sizeof(dst));
607
      ipa_ntoh(dst);
608
    }
609
  else
610
    dst = IPA_NONE;
611
  if (a[RTA_OIF])
612
    memcpy(&oif, RTA_DATA(a[RTA_OIF]), sizeof(oif));
613
  else
614
    oif = ~0;
615

    
616
  DBG("Got %I/%d, type=%d, oif=%d, table=%d, proto=%s\n", dst, i->rtm_dst_len, i->rtm_type, oif, i->rtm_table, p->p.name);
617

    
618
  switch (i->rtm_protocol)
619
    {
620
    case RTPROT_REDIRECT:
621
      src = KRT_SRC_REDIRECT;
622
      break;
623
    case RTPROT_KERNEL:
624
      DBG("Route originated in kernel, ignoring\n");
625
      return;
626
    case RTPROT_BIRD:
627
      if (!scan)
628
        {
629
          DBG("Echo of our own route, ignoring\n");
630
          return;
631
        }
632
      src = KRT_SRC_BIRD;
633
      break;
634
    default:
635
      src = KRT_SRC_ALIEN;
636
    }
637

    
638
  net = net_get(p->p.table, dst, i->rtm_dst_len);
639
  ra.proto = &p->p;
640
  ra.source = RTS_INHERIT;
641
  ra.scope = SCOPE_UNIVERSE;
642
  ra.cast = RTC_UNICAST;
643
  ra.flags = ra.aflags = 0;
644
  ra.from = IPA_NONE;
645
  ra.gw = IPA_NONE;
646
  ra.iface = NULL;
647
  ra.eattrs = NULL;
648

    
649
  switch (i->rtm_type)
650
    {
651
    case RTN_UNICAST:
652
      if (oif == ~0U)
653
        {
654
          log(L_ERR "KRT: Mysterious route with no OIF (%I/%d)", net->n.prefix, net->n.pxlen);
655
          return;
656
        }
657
      if (a[RTA_GATEWAY])
658
        {
659
          neighbor *ng;
660
          ra.dest = RTD_ROUTER;
661
          memcpy(&ra.gw, RTA_DATA(a[RTA_GATEWAY]), sizeof(ra.gw));
662
          ipa_ntoh(ra.gw);
663
          ng = neigh_find(&p->p, &ra.gw, 0);
664
          if (ng)
665
            ra.iface = ng->iface;
666
          else
667
            /* FIXME: Remove this warning? Handle it somehow... */
668
            log(L_WARN "Kernel told us to use non-neighbor %I for %I/%d", ra.gw, net->n.prefix, net->n.pxlen);
669
        }
670
      else
671
        {
672
          ra.dest = RTD_DEVICE;
673
          ra.iface = krt_temp_iface(p, oif);
674
        }
675
      break;
676
    case RTN_BLACKHOLE:
677
      ra.dest = RTD_BLACKHOLE;
678
      break;
679
    case RTN_UNREACHABLE:
680
      ra.dest = RTD_UNREACHABLE;
681
      break;
682
    case RTN_PROHIBIT:
683
      ra.dest = RTD_PROHIBIT;
684
      break;
685
    /* FIXME: What about RTN_THROW? */
686
    default:
687
      DBG("KRT: Ignoring route with type=%d\n", i->rtm_type);
688
      return;
689
    }
690

    
691
  if (i->rtm_scope != RT_SCOPE_UNIVERSE)
692
    {
693
      DBG("KRT: Ignoring route with scope=%d\n", i->rtm_scope);
694
      return;
695
    }
696

    
697
  e = rte_get_temp(&ra);
698
  e->net = net;
699
  e->u.krt.src = src;
700
  e->u.krt.proto = i->rtm_protocol;
701
  e->u.krt.type = i->rtm_type;
702
  if (a[RTA_PRIORITY])
703
    memcpy(&e->u.krt.metric, RTA_DATA(a[RTA_PRIORITY]), sizeof(e->u.krt.metric));
704
  else
705
    e->u.krt.metric = 0;
706
  if (scan)
707
    krt_got_route(p, e);
708
  else
709
    krt_got_route_async(p, e, new);
710
}
711

    
712
void
713
krt_scan_fire(struct krt_proto *p)        /* CONFIG_ALL_TABLES_AT_ONCE => p is NULL */
714
{
715
  struct nlmsghdr *h;
716

    
717
  nl_request_dump(RTM_GETROUTE);
718
  while (h = nl_get_scan())
719
    if (h->nlmsg_type == RTM_NEWROUTE || h->nlmsg_type == RTM_DELROUTE)
720
      nl_parse_route(h, 1);
721
    else
722
      log(L_DEBUG "nl_scan_fire: Unknown packet received (type=%d)", h->nlmsg_type);
723
}
724

    
725
/*
726
 *        Asynchronous Netlink interface
727
 */
728

    
729
static sock *nl_async_sk;                /* BIRD socket for asynchronous notifications */
730
static byte *nl_async_rx_buffer;        /* Receive buffer */
731

    
732
static void
733
nl_async_msg(struct nlmsghdr *h)
734
{
735
  switch (h->nlmsg_type)
736
    {
737
    case RTM_NEWROUTE:
738
    case RTM_DELROUTE:
739
      DBG("KRT: Received async route notification (%d)\n", h->nlmsg_type);
740
      nl_parse_route(h, 0);
741
      break;
742
    case RTM_NEWLINK:
743
    case RTM_DELLINK:
744
      DBG("KRT: Received async link notification (%d)\n", h->nlmsg_type);
745
      nl_parse_link(h, 0);
746
      break;
747
    case RTM_NEWADDR:
748
    case RTM_DELADDR:
749
      DBG("KRT: Received async address notification (%d)\n", h->nlmsg_type);
750
      nl_parse_addr(h);
751
      break;
752
    default:
753
      DBG("KRT: Received unknown async notification (%d)\n", h->nlmsg_type);
754
    }
755
}
756

    
757
static int
758
nl_async_hook(sock *sk, int size)
759
{
760
  struct iovec iov = { nl_async_rx_buffer, NL_RX_SIZE };
761
  struct sockaddr_nl sa;
762
  struct msghdr m = { (struct sockaddr *) &sa, sizeof(sa), &iov, 1, NULL, 0, 0 };
763
  struct nlmsghdr *h;
764
  int x;
765
  unsigned int len;
766

    
767
  nl_last_hdr = NULL;                /* Discard packets accidentally remaining in the rxbuf */
768
  x = recvmsg(sk->fd, &m, 0);
769
  if (x < 0)
770
    {
771
      if (errno == ENOBUFS)
772
        {
773
          /*
774
           *  Netlink reports some packets have been thrown away.
775
           *  One day we might react to it by asking for route table
776
           *  scan in near future.
777
           */
778
          return 1;        /* More data are likely to be ready */
779
        }
780
      else if (errno != EWOULDBLOCK)
781
        log(L_ERR "Netlink recvmsg: %m");
782
      return 0;
783
    }
784
  if (sa.nl_pid)                /* It isn't from the kernel */
785
    {
786
      DBG("Non-kernel packet\n");
787
      return 1;
788
    }
789
  h = (void *) nl_async_rx_buffer;
790
  len = x;
791
  if (m.msg_flags & MSG_TRUNC)
792
    {
793
      log(L_WARN "Netlink got truncated asynchronous message");
794
      return 1;
795
    }
796
  while (NLMSG_OK(h, len))
797
    {
798
      nl_async_msg(h);
799
      h = NLMSG_NEXT(h, len);
800
    }
801
  if (len)
802
    log(L_WARN "nl_async_hook: Found packet remnant of size %d", len);
803
  return 1;
804
}
805

    
806
static void
807
nl_open_async(void)
808
{
809
  sock *sk;
810
  struct sockaddr_nl sa;
811
  int fd;
812
  static int nl_open_tried = 0;
813

    
814
  if (nl_open_tried)
815
    return;
816
  nl_open_tried = 1;
817

    
818
  DBG("KRT: Opening async netlink socket\n");
819

    
820
  fd = socket(PF_NETLINK, SOCK_RAW, NETLINK_ROUTE);
821
  if (fd < 0)
822
    {
823
      log(L_ERR "Unable to open asynchronous rtnetlink socket: %m");
824
      return;
825
    }
826

    
827
  bzero(&sa, sizeof(sa));
828
  sa.nl_family = AF_NETLINK;
829
#ifdef IPV6
830
  sa.nl_groups = RTMGRP_LINK | RTMGRP_IPV6_IFADDR | RTMGRP_IPV6_ROUTE;
831
#else
832
  sa.nl_groups = RTMGRP_LINK | RTMGRP_IPV4_IFADDR | RTMGRP_IPV4_ROUTE;
833
#endif
834
  if (bind(fd, (struct sockaddr *) &sa, sizeof(sa)) < 0)
835
    {
836
      log(L_ERR "Unable to bind asynchronous rtnetlink socket: %m");
837
      return;
838
    }
839

    
840
  sk = nl_async_sk = sk_new(krt_pool);
841
  sk->type = SK_MAGIC;
842
  sk->rx_hook = nl_async_hook;
843
  sk->fd = fd;
844
  if (sk_open(sk))
845
    bug("Netlink: sk_open failed");
846

    
847
  if (!nl_async_rx_buffer)
848
    nl_async_rx_buffer = xmalloc(NL_RX_SIZE);
849
}
850

    
851
/*
852
 *        Interface to the UNIX krt module
853
 */
854

    
855
static u8 nl_cf_table[(NL_NUM_TABLES+7) / 8];
856

    
857
void
858
krt_scan_preconfig(struct config *c)
859
{
860
  bzero(&nl_cf_table, sizeof(nl_cf_table));
861
}
862

    
863
void
864
krt_scan_postconfig(struct krt_config *x)
865
{
866
  int id = x->scan.table_id;
867

    
868
  if (nl_cf_table[id/8] & (1 << (id%8)))
869
    cf_error("Multiple kernel syncers defined for table #%d", id);
870
  nl_cf_table[id/8] |= (1 << (id%8));
871
}
872

    
873
void
874
krt_scan_construct(struct krt_config *x)
875
{
876
#ifndef IPV6
877
  x->scan.table_id = RT_TABLE_MAIN;
878
#endif
879
}
880

    
881
void
882
krt_scan_start(struct krt_proto *p, int first)
883
{
884
  init_list(&p->scan.temp_ifs);
885
  nl_table_map[KRT_CF->scan.table_id] = p;
886
  if (first)
887
    {
888
      nl_open();
889
      nl_open_async();
890
    }
891
}
892

    
893
void
894
krt_scan_shutdown(struct krt_proto *p, int last)
895
{
896
}
897

    
898
void
899
krt_if_start(struct kif_proto *p)
900
{
901
  nl_open();
902
  nl_open_async();
903
}