summaryrefslogtreecommitdiffstats
path: root/src/ip.c
blob: a5958e95e43098556d6c7c7d94ef84756616ae45 (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
/*************************************************
*     Exim - an Internet mail transport agent    *
*************************************************/

/* Copyright (c) University of Cambridge 1995 - 2018 */
/* Copyright (c) The Exim Maintainers 2020 */
/* See the file NOTICE for conditions of use and distribution. */

/* Functions for doing things with sockets. With the advent of IPv6 this has
got messier, so that it's worth pulling out the code into separate functions
that other parts of Exim can call, especially as there are now several
different places in the code where sockets are used. */


#include "exim.h"


#if defined(TCP_FASTOPEN)
# if defined(MSG_FASTOPEN) || defined(EXIM_TFO_CONNECTX) || defined(EXIM_TFO_FREEBSD)
#  define EXIM_SUPPORT_TFO
# endif
#endif

/*************************************************
*             Create a socket                    *
*************************************************/

/* Socket creation happens in a number of places so it's packaged here for
convenience.

Arguments:
  type       SOCK_DGRAM or SOCK_STREAM
  af         AF_INET or AF_INET6

Returns:     socket number or -1 on failure
*/

int
ip_socket(int type, int af)
{
int sock = socket(af, type, 0);
if (sock < 0)
  log_write(0, LOG_MAIN, "IPv%c socket creation failed: %s",
    (af == AF_INET6)? '6':'4', strerror(errno));
return sock;
}




#if HAVE_IPV6
/*************************************************
*      Convert printing address to numeric       *
*************************************************/

/* This function converts the textual form of an IP address into a numeric form
in an appropriate structure in an IPv6 environment. The getaddrinfo() function
can (apparently) handle more complicated addresses (e.g. those containing
scopes) than inet_pton() in some environments. We use hints to tell it that the
input must be a numeric address.

However, apparently some operating systems (or libraries) don't support
getaddrinfo(), so there is a build-time option to revert to inet_pton() (which
does not support scopes).

Arguments:
  address     textual form of the address
  addr        where to copy back the answer

Returns:      nothing - failure provokes a panic-die
*/

static void
ip_addrinfo(const uschar *address, struct sockaddr_in6 *saddr)
{
#ifdef IPV6_USE_INET_PTON

  if (inet_pton(AF_INET6, CCS address, &saddr->sin6_addr) != 1)
    log_write(0, LOG_MAIN|LOG_PANIC_DIE, "unable to parse \"%s\" as an "
      "IP address", address);
  saddr->sin6_family = AF_INET6;

#else

  int rc;
  struct addrinfo hints, *res;
  memset(&hints, 0, sizeof(hints));
  hints.ai_family = AF_INET6;
  hints.ai_socktype = SOCK_STREAM;
  hints.ai_flags = AI_NUMERICHOST;
  if ((rc = getaddrinfo(CCS address, NULL, &hints, &res)) != 0 || res == NULL)
    log_write(0, LOG_MAIN|LOG_PANIC_DIE, "unable to parse \"%s\" as an "
      "IP address: %s", address,
      (rc == 0)? "NULL result returned" : gai_strerror(rc));
  memcpy(saddr, res->ai_addr, res->ai_addrlen);
  freeaddrinfo(res);

#endif
}
#endif  /* HAVE_IPV6 */


/*************************************************
*         Bind socket to interface and port      *
*************************************************/

int
ip_addr(void * sin_, int af, const uschar * address, int port)
{
union sockaddr_46 * sin = sin_;
memset(sin, 0, sizeof(*sin));

/* Setup code when using an IPv6 socket. The wildcard address is ":", to
ensure an IPv6 socket is used. */

#if HAVE_IPV6
if (af == AF_INET6)
  {
  if (address[0] == ':' && address[1] == 0)
    {
    sin->v6.sin6_family = AF_INET6;
    sin->v6.sin6_addr = in6addr_any;
    }
  else
    ip_addrinfo(address, &sin->v6);  /* Panic-dies on error */
  sin->v6.sin6_port = htons(port);
  return sizeof(sin->v6);
  }
else
#else     /* HAVE_IPv6 */
af = af;  /* Avoid compiler warning */
#endif    /* HAVE_IPV6 */

/* Setup code when using IPv4 socket. The wildcard address is "". */

  {
  sin->v4.sin_family = AF_INET;
  sin->v4.sin_port = htons(port);
  sin->v4.sin_addr.s_addr = address[0] == 0
    ? (S_ADDR_TYPE)INADDR_ANY
    : (S_ADDR_TYPE)inet_addr(CS address);
  return sizeof(sin->v4);
  }
}



/* This function binds a socket to a local interface address and port. For a
wildcard IPv6 bind, the address is ":".

Arguments:
  sock           the socket
  af             AF_INET or AF_INET6 - the socket type
  address        the IP address, in text form
  port           the IP port (host order)

Returns:         the result of bind()
*/

int
ip_bind(int sock, int af, uschar *address, int port)
{
union sockaddr_46 sin;
int s_len = ip_addr(&sin, af, address, port);
return bind(sock, (struct sockaddr *)&sin, s_len);
}



/*************************************************
*        Connect socket to remote host           *
*************************************************/

/* This function connects a socket to a remote address and port. The socket may
or may not have previously been bound to a local interface. The socket is not
closed, even in cases of error. It is expected that the calling function, which
created the socket, will be the one that closes it.

Arguments:
  sock        the socket
  af          AF_INET6 or AF_INET for the socket type
  address     the remote address, in text form
  port        the remote port
  timeout     a timeout (zero for indefinite timeout)
  fastopen_blob    non-null iff TCP_FASTOPEN can be used; may indicate early-data to
		be sent in SYN segment.  Any such data must be idempotent.

Returns:      0 on success; -1 on failure, with errno set
*/

int
ip_connect(int sock, int af, const uschar *address, int port, int timeout,
  const blob * fastopen_blob)
{
struct sockaddr_in s_in4;
struct sockaddr *s_ptr;
int s_len, rc, save_errno;

/* For an IPv6 address, use an IPv6 sockaddr structure. */

#if HAVE_IPV6
struct sockaddr_in6 s_in6;
if (af == AF_INET6)
  {
  memset(&s_in6, 0, sizeof(s_in6));
  ip_addrinfo(address, &s_in6);   /* Panic-dies on error */
  s_in6.sin6_port = htons(port);
  s_ptr = (struct sockaddr *)&s_in6;
  s_len = sizeof(s_in6);
  }
else
#else     /* HAVE_IPV6 */
af = af;  /* Avoid compiler warning */
#endif    /* HAVE_IPV6 */

/* For an IPv4 address, use an IPv4 sockaddr structure, even on a system with
IPv6 support. */

  {
  memset(&s_in4, 0, sizeof(s_in4));
  s_in4.sin_family = AF_INET;
  s_in4.sin_port = htons(port);
  s_in4.sin_addr.s_addr = (S_ADDR_TYPE)inet_addr(CCS address);
  s_ptr = (struct sockaddr *)&s_in4;
  s_len = sizeof(s_in4);
  }

/* If no connection timeout is set, just call connect() without setting a
timer, thereby allowing the inbuilt OS timeout to operate. */

callout_address = string_sprintf("[%s]:%d", address, port);
sigalrm_seen = FALSE;
if (timeout > 0) ALARM(timeout);

#ifdef EXIM_SUPPORT_TFO
/* TCP Fast Open, if the system has a cookie from a previous call to
this peer, can send data in the SYN packet.  The peer can send data
before it gets our ACK of its SYN,ACK - the latter is useful for
the SMTP banner.  Other (than SMTP) cases of TCP connections can
possibly use the data-on-syn, so support that too. */

if (fastopen_blob && f.tcp_fastopen_ok)
  {
# ifdef MSG_FASTOPEN
  /* This is a Linux implementation. */

  if ((rc = sendto(sock, fastopen_blob->data, fastopen_blob->len,
		    MSG_FASTOPEN | MSG_DONTWAIT, s_ptr, s_len)) >= 0)
	/* seen for with-data, experimental TFO option, with-cookie case */
	/* seen for with-data, proper TFO opt, with-cookie case */
    {
    DEBUG(D_transport|D_v)
      debug_printf(" TFO mode connection attempt to %s, %lu data\n",
	address, (unsigned long)fastopen_blob->len);
    /*XXX also seen on successful TFO, sigh */
    tcp_out_fastopen = fastopen_blob->len > 0 ?  TFO_ATTEMPTED_DATA : TFO_ATTEMPTED_NODATA;
    }
  else switch (errno)
    {
    case EINPROGRESS:	/* expected if we had no cookie for peer */
	/* seen for no-data, proper TFO option, both cookie-request and with-cookie cases */
	/*  apparently no visibility of the diffference at this point */
	/* seen for with-data, proper TFO opt, cookie-req */
	/*   with netwk delay, post-conn tcp_info sees unacked 1 for R, 2 for C; code in smtp_out.c */
	/* ? older Experimental TFO option behaviour ? */
      DEBUG(D_transport|D_v) debug_printf(" TFO mode sendto, %s data: EINPROGRESS\n",
	fastopen_blob->len > 0 ? "with"  : "no");
      if (!fastopen_blob->data)
	{
	tcp_out_fastopen = TFO_ATTEMPTED_NODATA;		/* we tried; unknown if useful yet */
	rc = 0;
	}
      else					/* queue unsent data */
	rc = send(sock, fastopen_blob->data, fastopen_blob->len, 0);
      break;

    case EOPNOTSUPP:
      DEBUG(D_transport)
	debug_printf("Tried TCP Fast Open but apparently not enabled by sysctl\n");
      goto legacy_connect;

    case EPIPE:
      DEBUG(D_transport)
	debug_printf("Tried TCP Fast Open but kernel too old to support it\n");
      goto legacy_connect;
    }

# elif defined(EXIM_TFO_FREEBSD)
  /* Re: https://people.freebsd.org/~pkelsey/tfo-tools/tfo-client.c */

  if (setsockopt(sock, IPPROTO_TCP, TCP_FASTOPEN, &on, sizeof(on)) < 0)
    {
    DEBUG(D_transport)
      debug_printf("Tried TCP Fast Open but apparently not enabled by sysctl\n");
    goto legacy_connect;
    }
  if ((rc = sendto(sock, fastopen_blob->data, fastopen_blob->len, 0,
		    s_ptr, s_len)) >= 0)
    {
    DEBUG(D_transport|D_v)
      debug_printf(" TFO mode connection attempt to %s, %lu data\n",
	address, (unsigned long)fastopen_blob->len);
    tcp_out_fastopen = fastopen_blob->len > 0 ?  TFO_ATTEMPTED_DATA : TFO_ATTEMPTED_NODATA;
    }

# elif defined(EXIM_TFO_CONNECTX)
  /* MacOS */
  sa_endpoints_t ends = {
    .sae_srcif = 0, .sae_srcaddr = NULL, .sae_srcaddrlen = 0,
    .sae_dstaddr = s_ptr, .sae_dstaddrlen = s_len };
  struct iovec iov = {
    .iov_base = fastopen_blob->data, .iov_len = fastopen_blob->len };
  size_t len;

  if ((rc = connectx(sock, &ends, SAE_ASSOCID_ANY,
	     CONNECT_DATA_IDEMPOTENT, &iov, 1, &len, NULL)) == 0)
    {
    DEBUG(D_transport|D_v)
      debug_printf(" TFO mode connection attempt to %s, %lu data\n",
	address, (unsigned long)fastopen_blob->len);
    tcp_out_fastopen = fastopen_blob->len > 0 ?  TFO_ATTEMPTED_DATA : TFO_ATTEMPTED_NODATA;

    if (len != fastopen_blob->len)
      DEBUG(D_transport|D_v)
	debug_printf(" only queued %lu data!\n", (unsigned long)len);
    }
  else if (errno == EINPROGRESS)
    {
    DEBUG(D_transport|D_v) debug_printf(" TFO mode connectx, %s data: EINPROGRESS\n",
      fastopen_blob->len > 0 ? "with"  : "no");
    if (!fastopen_blob->data)
      {
      tcp_out_fastopen = TFO_ATTEMPTED_NODATA;		/* we tried; unknown if useful yet */
      rc = 0;
      }
    else	/* assume that no data was queued; block in send */
      rc = send(sock, fastopen_blob->data, fastopen_blob->len, 0);
    }
# endif
  }
else
#endif	/*EXIM_SUPPORT_TFO*/
  {
#if defined(EXIM_SUPPORT_TFO) && !defined(EXIM_TFO_CONNECTX)
legacy_connect:
#endif

  DEBUG(D_transport|D_v) if (fastopen_blob)
    debug_printf(" non-TFO mode connection attempt to %s, %lu data\n",
      address, (unsigned long)fastopen_blob->len);
  if ((rc = connect(sock, s_ptr, s_len)) >= 0)
    if (  fastopen_blob && fastopen_blob->data && fastopen_blob->len
       && send(sock, fastopen_blob->data, fastopen_blob->len, 0) < 0)
	rc = -1;
  }

save_errno = errno;
ALARM_CLR(0);

/* There is a testing facility for simulating a connection timeout, as I
can't think of any other way of doing this. It converts a connection refused
into a timeout if the timeout is set to 999999. */

if (f.running_in_test_harness  && save_errno == ECONNREFUSED && timeout == 999999)
  {
  rc = -1;
  save_errno = EINTR;
  sigalrm_seen = TRUE;
  }

/* Success */

if (rc >= 0)
  return 0;

/* A failure whose error code is "Interrupted system call" is in fact
an externally applied timeout if the signal handler has been run. */

errno = save_errno == EINTR && sigalrm_seen ? ETIMEDOUT : save_errno;
return -1;
}



/*************************************************
*    Create connected socket to remote host      *
*************************************************/

/* Create a socket and connect to host (name or number, ipv6 ok)
   at one of port-range.

Arguments:
  type          SOCK_DGRAM or SOCK_STREAM
  af            AF_INET6 or AF_INET for the socket type
  hostname	host name, or ip address (as text)
  portlo,porthi the remote port range
  timeout       a timeout
  connhost	if not NULL, host_item to be filled in with connection details
  errstr        pointer for allocated string on error
  fastopen_blob	with SOCK_STREAM, if non-null, request TCP Fast Open.
		Additionally, optional idempotent early-data to send

Return:
  socket fd, or -1 on failure (having allocated an error string)
*/
int
ip_connectedsocket(int type, const uschar * hostname, int portlo, int porthi,
      int timeout, host_item * connhost, uschar ** errstr, const blob * fastopen_blob)
{
int namelen;
host_item shost;
int af = 0, fd, fd4 = -1, fd6 = -1;

shost.next = NULL;
shost.address = NULL;
shost.port = portlo;
shost.mx = -1;

namelen = Ustrlen(hostname);

/* Anything enclosed in [] must be an IP address. */

if (hostname[0] == '[' &&
    hostname[namelen - 1] == ']')
  {
  uschar * host = string_copyn(hostname+1, namelen-2);
  if (string_is_ip_address(host, NULL) == 0)
    {
    *errstr = string_sprintf("malformed IP address \"%s\"", hostname);
    return -1;
    }
  shost.name = shost.address = host;
  }

/* Otherwise check for an unadorned IP address */

else if (string_is_ip_address(hostname, NULL) != 0)
  shost.name = shost.address = string_copyn(hostname, namelen);

/* Otherwise lookup IP address(es) from the name */

else
  {
  shost.name = string_copyn(hostname, namelen);
  if (host_find_byname(&shost, NULL, HOST_FIND_QUALIFY_SINGLE,
      NULL, FALSE) != HOST_FOUND)
    {
    *errstr = string_sprintf("no IP address found for host %s", shost.name);
    return -1;
    }
  }

/* Try to connect to the server - test each IP till one works */

for (host_item * h = &shost; h; h = h->next)
  {
  fd = Ustrchr(h->address, ':') != 0
    ? fd6 < 0 ? (fd6 = ip_socket(type, af = AF_INET6)) : fd6
    : fd4 < 0 ? (fd4 = ip_socket(type, af = AF_INET )) : fd4;

  if (fd < 0)
    {
    *errstr = string_sprintf("failed to create socket: %s", strerror(errno));
    goto bad;
    }

  for (int port = portlo; port <= porthi; port++)
    if (ip_connect(fd, af, h->address, port, timeout, fastopen_blob) == 0)
      {
      if (fd != fd6) close(fd6);
      if (fd != fd4) close(fd4);
      if (connhost)
	{
	h->port = port;
	*connhost = *h;
	connhost->next = NULL;
	}
      return fd;
      }
  }

*errstr = string_sprintf("failed to connect to any address for %s: %s",
  hostname, strerror(errno));

bad:
  close(fd4); close(fd6); return -1;
}


/*XXX TFO? */
int
ip_tcpsocket(const uschar * hostport, uschar ** errstr, int tmo,
  host_item * connhost)
{
int scan;
uschar hostname[256];
unsigned int portlow, porthigh;

/* extract host and port part */
scan = sscanf(CS hostport, "%255s %u-%u", hostname, &portlow, &porthigh);
if (scan != 3)
  {
  if (scan != 2)
    {
    *errstr = string_sprintf("invalid socket '%s'", hostport);
    return -1;
    }
  porthigh = portlow;
  }

return ip_connectedsocket(SOCK_STREAM, hostname, portlow, porthigh,
			  tmo, connhost, errstr, NULL);
}

int
ip_unixsocket(const uschar * path, uschar ** errstr)
{
int sock;
struct sockaddr_un server;

if ((sock = socket(AF_UNIX, SOCK_STREAM, 0)) < 0)
  {
  *errstr = US"can't open UNIX socket.";
  return -1;
  }

callout_address = string_copy(path);
server.sun_family = AF_UNIX;
Ustrncpy(US server.sun_path, path, sizeof(server.sun_path)-1);
server.sun_path[sizeof(server.sun_path)-1] = '\0';
if (connect(sock, (struct sockaddr *) &server, sizeof(server)) < 0)
  {
  int err = errno;
  (void)close(sock);
  *errstr = string_sprintf("unable to connect to UNIX socket (%s): %s",
		path, strerror(err));
  return -1;
  }
return sock;
}

/* spec is either an absolute path (with a leading /), or
a host (name or IP) and port (whitespace-separated).
The port can be a range, dash-separated, or a single number.

For a TCP socket, optionally fill in a  host_item.
*/
int
ip_streamsocket(const uschar * spec, uschar ** errstr, int tmo,
  host_item * connhost)
{
return *spec == '/'
  ? ip_unixsocket(spec, errstr) : ip_tcpsocket(spec, errstr, tmo, connhost);
}

/*************************************************
*         Set keepalive on a socket              *
*************************************************/

/* Can be called for both incoming and outgoing sockets.

Arguments:
  sock       the socket
  address    the remote host address, for failure logging
  torf       true for outgoing connection, false for incoming

Returns:     nothing
*/

void
ip_keepalive(int sock, const uschar *address, BOOL torf)
{
int fodder = 1;
if (setsockopt(sock, SOL_SOCKET, SO_KEEPALIVE,
    US (&fodder), sizeof(fodder)) != 0)
  log_write(0, LOG_MAIN, "setsockopt(SO_KEEPALIVE) on connection %s %s "
    "failed: %s", torf? "to":"from", address, strerror(errno));
}



/*************************************************
*         Receive from a socket with timeout     *
*************************************************/

/*
Arguments:
  fd          the file descriptor
  timelimit   the timeout endpoint, seconds-since-epoch
Returns:      TRUE => ready for i/o
              FALSE => timed out, or other error
*/
BOOL
fd_ready(int fd, time_t timelimit)
{
fd_set select_inset;
int time_left = timelimit - time(NULL);
int rc;

if (time_left <= 0)
  {
  errno = ETIMEDOUT;
  return FALSE;
  }
/* Wait until the socket is ready */

do
  {
  struct timeval tv = { .tv_sec = time_left, .tv_usec = 0 };
  FD_ZERO (&select_inset);
  FD_SET (fd, &select_inset);

  /*DEBUG(D_transport) debug_printf("waiting for data on fd\n");*/
  rc = select(fd + 1, (SELECT_ARG2_TYPE *)&select_inset, NULL, NULL, &tv);

  /* If some interrupt arrived, just retry. We presume this to be rare,
  but it can happen (e.g. the SIGUSR1 signal sent by exiwhat causes
  select() to exit).

  Aug 2004: Somebody set up a cron job that ran exiwhat every 2 minutes, making
  the interrupt not at all rare. Since the timeout is typically more than 2
  minutes, the effect was to block the timeout completely. To prevent this
  happening again, we do an explicit time test and adjust the timeout
  accordingly */

  if (rc < 0 && errno == EINTR)
    {
    DEBUG(D_transport) debug_printf("EINTR while waiting for socket data\n");

    /* Watch out, 'continue' jumps to the condition, not to the loops top */
    if ((time_left = timelimit - time(NULL)) > 0) continue;
    }

  if (rc <= 0)
    {
    errno = ETIMEDOUT;
    return FALSE;
    }

  /* Checking the FD_ISSET is not enough, if we're interrupted, the
  select_inset may still contain the 'input'. */
  }
while (rc < 0 || !FD_ISSET(fd, &select_inset));
return TRUE;
}

/* The timeout is implemented using select(), and we loop to cover select()
getting interrupted, and the possibility of select() returning with a positive
result but no ready descriptor. Is this in fact possible?

Arguments:
  cctx        the connection context (socket fd, possibly TLS context)
  buffer      to read into
  bufsize     the buffer size
  timelimit   the timeout endpoint, seconds-since-epoch

Returns:      > 0 => that much data read
              <= 0 on error or EOF; errno set - zero for EOF
*/

int
ip_recv(client_conn_ctx * cctx, uschar * buffer, int buffsize, time_t timelimit)
{
int rc;

if (!fd_ready(cctx->sock, timelimit))
  return -1;

/* The socket is ready, read from it (via TLS if it's active). On EOF (i.e.
close down of the connection), set errno to zero; otherwise leave it alone. */

#ifndef DISABLE_TLS
if (cctx->tls_ctx)					/* client TLS */
  rc = tls_read(cctx->tls_ctx, buffer, buffsize);
else if (tls_in.active.sock == cctx->sock)		/* server TLS */
  rc = tls_read(NULL, buffer, buffsize);
else
#endif
  rc = recv(cctx->sock, buffer, buffsize, 0);

if (rc > 0) return rc;
if (rc == 0) errno = 0;
return -1;
}




/*************************************************
*    Lookup address family of potential socket   *
*************************************************/

/* Given a file-descriptor, check to see if it's a socket and, if so,
return the address family; detects IPv4 vs IPv6.  If not a socket then
return -1.

The value 0 is typically AF_UNSPEC, which should not be seen on a connected
fd.  If the return is -1, the errno will be from getsockname(); probably
ENOTSOCK or ECONNRESET.

Arguments:     socket-or-not fd
Returns:       address family or -1
*/

int
ip_get_address_family(int fd)
{
struct sockaddr_storage ss;
socklen_t sslen = sizeof(ss);

if (getsockname(fd, (struct sockaddr *) &ss, &sslen) < 0)
  return -1;

return (int) ss.ss_family;
}




/*************************************************
*       Lookup DSCP settings for a socket        *
*************************************************/

struct dscp_name_tableentry {
  const uschar *name;
  int value;
};
/* Keep both of these tables sorted! */
static struct dscp_name_tableentry dscp_table[] = {
#ifdef IPTOS_DSCP_AF11
    { CUS"af11", IPTOS_DSCP_AF11 },
    { CUS"af12", IPTOS_DSCP_AF12 },
    { CUS"af13", IPTOS_DSCP_AF13 },
    { CUS"af21", IPTOS_DSCP_AF21 },
    { CUS"af22", IPTOS_DSCP_AF22 },
    { CUS"af23", IPTOS_DSCP_AF23 },
    { CUS"af31", IPTOS_DSCP_AF31 },
    { CUS"af32", IPTOS_DSCP_AF32 },
    { CUS"af33", IPTOS_DSCP_AF33 },
    { CUS"af41", IPTOS_DSCP_AF41 },
    { CUS"af42", IPTOS_DSCP_AF42 },
    { CUS"af43", IPTOS_DSCP_AF43 },
    { CUS"ef", IPTOS_DSCP_EF },
#endif
#ifdef IPTOS_LOWCOST
    { CUS"lowcost", IPTOS_LOWCOST },
#endif
    { CUS"lowdelay", IPTOS_LOWDELAY },
#ifdef IPTOS_MINCOST
    { CUS"mincost", IPTOS_MINCOST },
#endif
    { CUS"reliability", IPTOS_RELIABILITY },
    { CUS"throughput", IPTOS_THROUGHPUT }
};
static int dscp_table_size =
  sizeof(dscp_table) / sizeof(struct dscp_name_tableentry);

/* DSCP values change by protocol family, and so do the options used for
setsockopt(); this utility does all the lookups.  It takes an unexpanded
option string, expands it, strips off affix whitespace, then checks if it's
a number.  If all of what's left is a number, then that's how the option will
be parsed and success/failure is a range check.  If it's not all a number,
then it must be a supported keyword.

Arguments:
  dscp_name   a string, so far unvalidated
  af          address_family in use
  level       setsockopt level to use
  optname     setsockopt name to use
  dscp_value  value for dscp_name

Returns: TRUE if okay to setsockopt(), else FALSE

*level and *optname may be set even if FALSE is returned
*/

BOOL
dscp_lookup(const uschar *dscp_name, int af,
    int *level, int *optname, int *dscp_value)
{
uschar *dscp_lookup, *p;
int first, last;
long rawlong;

if (af == AF_INET)
  {
  *level = IPPROTO_IP;
  *optname = IP_TOS;
  }
#if HAVE_IPV6 && defined(IPV6_TCLASS)
else if (af == AF_INET6)
  {
  *level = IPPROTO_IPV6;
  *optname = IPV6_TCLASS;
  }
#endif
else
  {
  DEBUG(D_transport)
    debug_printf("Unhandled address family %d in dscp_lookup()\n", af);
  return FALSE;
  }
if (!dscp_name)
  {
  DEBUG(D_transport)
    debug_printf("[empty DSCP]\n");
  return FALSE;
  }
dscp_lookup = expand_string(US dscp_name);
if (dscp_lookup == NULL || *dscp_lookup == '\0')
  return FALSE;

p = dscp_lookup + Ustrlen(dscp_lookup) - 1;
while (isspace(*p)) *p-- = '\0';
while (isspace(*dscp_lookup) && dscp_lookup < p) dscp_lookup++;
if (*dscp_lookup == '\0')
  return FALSE;

rawlong = Ustrtol(dscp_lookup, &p, 0);
if (p != dscp_lookup && *p == '\0')
  {
  /* We have six bits available, which will end up shifted to fit in 0xFC mask.
  RFC 2597 defines the values unshifted. */
  if (rawlong < 0 || rawlong > 0x3F)
    {
    DEBUG(D_transport)
      debug_printf("DSCP value %ld out of range, ignored.\n", rawlong);
    return FALSE;
    }
  *dscp_value = rawlong << 2;
  return TRUE;
  }

first = 0;
last = dscp_table_size;
while (last > first)
  {
  int middle = (first + last)/2;
  int c = Ustrcmp(dscp_lookup, dscp_table[middle].name);
  if (c == 0)
    {
    *dscp_value = dscp_table[middle].value;
    return TRUE;
    }
  else if (c > 0)
    first = middle + 1;
  else
    last = middle;
  }
return FALSE;
}

void
dscp_list_to_stream(FILE *stream)
{
for (int i = 0; i < dscp_table_size; ++i)
  fprintf(stream, "%s\n", dscp_table[i].name);
}


/* End of ip.c */
/* vi: aw ai sw=2
*/