aboutsummaryrefslogtreecommitdiff
path: root/lib/connect.c
blob: 26bf283299040a573a5e5d6a3cbef4dd54d2cc37 (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
/***************************************************************************
 *                                  _   _ ____  _
 *  Project                     ___| | | |  _ \| |
 *                             / __| | | | |_) | |
 *                            | (__| |_| |  _ <| |___
 *                             \___|\___/|_| \_\_____|
 *
 * Copyright (C) 1998 - 2004, Daniel Stenberg, <daniel@haxx.se>, et al.
 *
 * This software is licensed as described in the file COPYING, which
 * you should have received as part of this distribution. The terms
 * are also available at http://curl.haxx.se/docs/copyright.html.
 *
 * You may opt to use, copy, modify, merge, publish, distribute and/or sell
 * copies of the Software, and permit persons to whom the Software is
 * furnished to do so, under the terms of the COPYING file.
 *
 * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
 * KIND, either express or implied.
 *
 * $Id$
 ***************************************************************************/

#include "setup.h"

#ifndef WIN32
/* headers for non-win32 */
#include <sys/time.h>
#ifdef HAVE_SYS_TYPES_H
#include <sys/types.h>
#endif
#ifdef HAVE_SYS_SOCKET_H
#include <sys/socket.h>
#endif
#ifdef HAVE_NETINET_IN_H
#include <netinet/in.h> /* <netinet/tcp.h> may need it */
#endif
#ifdef HAVE_NETINET_TCP_H
#include <netinet/tcp.h> /* for TCP_NODELAY */
#endif
#ifdef HAVE_SYS_IOCTL_H
#include <sys/ioctl.h>
#endif
#ifdef HAVE_UNISTD_H
#include <unistd.h>
#endif
#ifdef HAVE_NETDB_H
#include <netdb.h>
#endif
#ifdef HAVE_FCNTL_H
#include <fcntl.h>
#endif
#ifdef HAVE_NETINET_IN_H
#include <netinet/in.h>
#endif
#ifdef HAVE_ARPA_INET_H
#include <arpa/inet.h>
#endif
#ifdef HAVE_STDLIB_H
#include <stdlib.h> /* required for free() prototype, without it, this crashes
                       on macos 68K */
#endif
#if (defined(HAVE_FIONBIO) && defined(__NOVELL_LIBC__))
#include <sys/filio.h>
#endif
#if (defined(NETWARE) && defined(__NOVELL_LIBC__))
#undef in_addr_t
#define in_addr_t unsigned long
#endif
#ifdef	VMS
#include <in.h>
#include <inet.h>
#endif

#endif
#include <stdio.h>
#include <errno.h>
#include <string.h>

#ifndef TRUE
#define TRUE 1
#define FALSE 0
#endif

#ifdef WIN32
#include <windows.h>
#define EINPROGRESS WSAEINPROGRESS
#define EWOULDBLOCK WSAEWOULDBLOCK
#define EISCONN     WSAEISCONN
#define ENOTSOCK    WSAENOTSOCK
#define ECONNREFUSED WSAECONNREFUSED
#endif

#include "urldata.h"
#include "sendf.h"
#include "if2ip.h"
#include "strerror.h"
#include "connect.h"
#include "memory.h"

/* The last #include file should be: */
#include "memdebug.h"

static bool verifyconnect(curl_socket_t sockfd, int *error);

/*
 * Curl_ourerrno() returns the errno (or equivalent) on this platform to
 * hide platform specific for the function that calls this.
 */
int Curl_ourerrno(void)
{
#ifdef WIN32
  return (int)GetLastError();
#else
  return errno;
#endif
}

/*
 * Curl_nonblock() set the given socket to either blocking or non-blocking
 * mode based on the 'nonblock' boolean argument. This function is highly
 * portable.
 */
int Curl_nonblock(curl_socket_t sockfd,    /* operate on this */
                  int nonblock   /* TRUE or FALSE */)
{
#undef SETBLOCK
#ifdef HAVE_O_NONBLOCK
  /* most recent unix versions */
  int flags;

  flags = fcntl(sockfd, F_GETFL, 0);
  if (TRUE == nonblock)
    return fcntl(sockfd, F_SETFL, flags | O_NONBLOCK);
  else
    return fcntl(sockfd, F_SETFL, flags & (~O_NONBLOCK));
#define SETBLOCK 1
#endif

#ifdef HAVE_FIONBIO
  /* older unix versions */
  int flags;

  flags = nonblock;
  return ioctl(sockfd, FIONBIO, &flags);
#define SETBLOCK 2
#endif

#ifdef HAVE_IOCTLSOCKET
  /* Windows? */
  unsigned long flags;
  flags = nonblock;
  return ioctlsocket(sockfd, FIONBIO, &flags);
#define SETBLOCK 3
#endif

#ifdef HAVE_IOCTLSOCKET_CASE
  /* presumably for Amiga */
  return IoctlSocket(sockfd, FIONBIO, (long)nonblock);
#define SETBLOCK 4
#endif

#ifdef HAVE_SO_NONBLOCK
  /* BeOS */
  long b = nonblock ? 1 : 0;
  return setsockopt(sockfd, SOL_SOCKET, SO_NONBLOCK, &b, sizeof(b));
#define SETBLOCK 5
#endif

#ifdef HAVE_DISABLED_NONBLOCKING
  return 0; /* returns success */
#define SETBLOCK 6
#endif

#ifndef SETBLOCK
#error "no non-blocking method was found/used/set"
#endif
}

/*
 * waitconnect() waits for a TCP connect on the given socket for the specified
 * number if milliseconds. It returns:
 * 0    fine connect
 * -1   select() error
 * 1    select() timeout
 * 2    select() returned with an error condition fd_set
 */

#define WAITCONN_CONNECTED     0
#define WAITCONN_SELECT_ERROR -1
#define WAITCONN_TIMEOUT       1
#define WAITCONN_FDSET_ERROR   2

static
int waitconnect(curl_socket_t sockfd, /* socket */
                long timeout_msec)
{
  fd_set fd;
  fd_set errfd;
  struct timeval interval;
  int rc;
#ifdef mpeix
  /* Call this function once now, and ignore the results. We do this to
     "clear" the error state on the socket so that we can later read it
     reliably. This is reported necessary on the MPE/iX operating system. */
  verifyconnect(sockfd, NULL);
#endif

  /* now select() until we get connect or timeout */
  FD_ZERO(&fd);
  FD_SET(sockfd, &fd);

  FD_ZERO(&errfd);
  FD_SET(sockfd, &errfd);

  interval.tv_sec = timeout_msec/1000;
  timeout_msec -= interval.tv_sec*1000;

  interval.tv_usec = timeout_msec*1000;

  rc = select(sockfd+1, NULL, &fd, &errfd, &interval);
  if(-1 == rc)
    /* error, no connect here, try next */
    return WAITCONN_SELECT_ERROR;

  else if(0 == rc)
    /* timeout, no connect today */
    return WAITCONN_TIMEOUT;

  if(FD_ISSET(sockfd, &errfd))
    /* error condition caught */
    return WAITCONN_FDSET_ERROR;

  /* we have a connect! */
  return WAITCONN_CONNECTED;
}

static CURLcode bindlocal(struct connectdata *conn,
                          curl_socket_t sockfd)
{
#ifdef HAVE_INET_NTOA
  bool bindworked = FALSE;
  struct SessionHandle *data = conn->data;

  /*************************************************************
   * Select device to bind socket to
   *************************************************************/
  if (strlen(data->set.device)<255) {
    struct Curl_dns_entry *h=NULL;
    size_t size;
    char myhost[256] = "";
    in_addr_t in;
    int rc;
    bool was_iface = FALSE;

    /* First check if the given name is an IP address */
    in=inet_addr(data->set.device);

    if((in == CURL_INADDR_NONE) &&
       Curl_if2ip(data->set.device, myhost, sizeof(myhost))) {
      /*
       * We now have the numerical IPv4-style x.y.z.w in the 'myhost' buffer
       */
      rc = Curl_resolv(conn, myhost, 0, &h);
      if(rc == CURLRESOLV_PENDING)
        (void)Curl_wait_for_resolv(conn, &h);

      if(h)
        was_iface = TRUE;
    }

    if(!was_iface) {
      /*
       * This was not an interface, resolve the name as a host name
       * or IP number
       */
      rc = Curl_resolv(conn, data->set.device, 0, &h);
      if(rc == CURLRESOLV_PENDING)
        (void)Curl_wait_for_resolv(conn, &h);

      if(h)
        /* we know data->set.device is shorter than the myhost array */
        strcpy(myhost, data->set.device);
    }

    if(! *myhost) {
      /* need to fix this
         h=Curl_gethost(data,
         getmyhost(*myhost,sizeof(myhost)),
         hostent_buf,
         sizeof(hostent_buf));
      */
      failf(data, "Couldn't bind to '%s'", data->set.device);
      return CURLE_HTTP_PORT_FAILED;
    }

    infof(data, "We bind local end to %s\n", myhost);

#ifdef SO_BINDTODEVICE
    /* I am not sure any other OSs than Linux that provide this feature, and
     * at the least I cannot test. --Ben
     *
     * This feature allows one to tightly bind the local socket to a
     * particular interface.  This will force even requests to other local
     * interfaces to go out the external interface.
     *
     */
    if (was_iface) {
      /* Only bind to the interface when specified as interface, not just as a
       * hostname or ip address.
       */
      if (setsockopt(sockfd, SOL_SOCKET, SO_BINDTODEVICE,
                     data->set.device, strlen(data->set.device)+1) != 0) {
        /* printf("Failed to BINDTODEVICE, socket: %d  device: %s error: %s\n",
           sockfd, data->set.device, Curl_strerror(Curl_ourerrno())); */
        infof(data, "SO_BINDTODEVICE %s failed\n",
              data->set.device);
        /* This is typically "errno 1, error: Operation not permitted" if
           you're not running as root or another suitable privileged user */
      }
    }
#endif

    in=inet_addr(myhost);
    if (CURL_INADDR_NONE != in) {

      if ( h ) {
        Curl_addrinfo *addr = h->addr;

        Curl_resolv_unlock(data, h);
        /* we don't need it anymore after this function has returned */

#ifdef ENABLE_IPV6
        if( bind(sockfd, addr->ai_addr, addr->ai_addrlen) >= 0) {
          /* we succeeded to bind */
          struct sockaddr_in6 add;

          bindworked = TRUE;

          size = sizeof(add);
          if(getsockname(sockfd, (struct sockaddr *) &add,
                         (socklen_t *)&size)<0) {
            failf(data, "getsockname() failed");
            return CURLE_HTTP_PORT_FAILED;
          }
        }
#else
        {
          struct sockaddr_in sa;

          memset((char *)&sa, 0, sizeof(sa));
          memcpy((char *)&sa.sin_addr, addr->h_addr, addr->h_length);
          sa.sin_family = AF_INET;
          sa.sin_addr.s_addr = in;
          sa.sin_port = 0; /* get any port */

          if( bind(sockfd, (struct sockaddr *)&sa, sizeof(sa)) >= 0) {
            /* we succeeded to bind */
            struct sockaddr_in add;

            bindworked = TRUE;

            size = sizeof(add);
            if(getsockname(sockfd, (struct sockaddr *) &add,
                           (socklen_t *)&size)<0) {
              failf(data, "getsockname() failed");
              return CURLE_HTTP_PORT_FAILED;
            }
          }
        }
#endif
        if(!bindworked) {
          failf(data, "%s", Curl_strerror(conn, Curl_ourerrno()));
          return CURLE_HTTP_PORT_FAILED;
        }

      } /* end of if  h */
      else {
	failf(data,"could't find my own IP address (%s)", myhost);
	return CURLE_HTTP_PORT_FAILED;
      }
    } /* end of inet_addr */

    else {
      failf(data, "could't find my own IP address (%s)", myhost);
      return CURLE_HTTP_PORT_FAILED;
    }

    return CURLE_OK;

  } /* end of device selection support */
#endif /* end of HAVE_INET_NTOA */

  return CURLE_HTTP_PORT_FAILED;
}

/*
 * verifyconnect() returns TRUE if the connect really has happened.
 */
static bool verifyconnect(curl_socket_t sockfd, int *error)
{
  bool rc = TRUE;
#ifdef SO_ERROR
  int err = 0;
  socklen_t errSize = sizeof(err);

#ifdef WIN32
  /*
   * In October 2003 we effectively nullified this function on Windows due to
   * problems with it using all CPU in multi-threaded cases.
   *
   * In May 2004, we bring it back to offer more info back on connect failures.
   * Gisle Vanem could reproduce the former problems with this function, but
   * could avoid them by adding this SleepEx() call below:
   *
   *    "I don't have Rational Quantify, but the hint from his post was
   *    ntdll::NtRemoveIoCompletion(). So I'd assume the SleepEx (or maybe
   *    just Sleep(0) would be enough?) would release whatever
   *    mutex/critical-section the ntdll call is waiting on.
   *
   *    Someone got to verify this on Win-NT 4.0, 2000."
   */
  SleepEx(0, FALSE);
#endif

  if( -1 == getsockopt(sockfd, SOL_SOCKET, SO_ERROR,
                       (void *)&err, &errSize))
    err = Curl_ourerrno();

  if ((0 == err) || (EISCONN == err))
    /* we are connected, awesome! */
    rc = TRUE;
  else
    /* This wasn't a successful connect */
    rc = FALSE;
  if (error)
    *error = err;
#else
  (void)sockfd;
  if (error)
    *error = Curl_ourerrno();
#endif
  return rc;
}

/*
 * Curl_is_connected() is used from the multi interface to check if the
 * firstsocket has connected.
 */

CURLcode Curl_is_connected(struct connectdata *conn,
                           curl_socket_t sockfd,
                           bool *connected)
{
  int rc;
  struct SessionHandle *data = conn->data;

  *connected = FALSE; /* a very negative world view is best */

  if(data->set.timeout || data->set.connecttimeout) {
    /* there is a timeout set */

    /* Evaluate in milliseconds how much time that has passed */
    long has_passed = Curl_tvdiff(Curl_tvnow(), data->progress.start);

    /* subtract the most strict timeout of the ones */
    if(data->set.timeout && data->set.connecttimeout) {
      if (data->set.timeout < data->set.connecttimeout)
        has_passed -= data->set.timeout*1000;
      else
        has_passed -= data->set.connecttimeout*1000;
    }
    else if(data->set.timeout)
      has_passed -= data->set.timeout*1000;
    else
      has_passed -= data->set.connecttimeout*1000;

    if(has_passed > 0 ) {
      /* time-out, bail out, go home */
      failf(data, "Connection time-out");
      return CURLE_OPERATION_TIMEOUTED;
    }
  }
  if(conn->bits.tcpconnect) {
    /* we are connected already! */
    *connected = TRUE;
    return CURLE_OK;
  }

  /* check for connect without timeout as we want to return immediately */
  rc = waitconnect(sockfd, 0);

  if(0 == rc) {
    if (verifyconnect(sockfd,NULL)) {
      /* we are connected, awesome! */
      *connected = TRUE;
      return CURLE_OK;
    }
    /* nope, not connected for real */
    failf(data, "Connection failed");
    return CURLE_COULDNT_CONNECT;
  }
  else if(1 != rc) {
    int error = Curl_ourerrno();
    failf(data, "Failed connect to %s:%d; %s",
          conn->host.name, conn->port, Curl_strerror(conn,error));
    return CURLE_COULDNT_CONNECT;
  }
  /*
   * If the connection phase is "done" here, we should attempt to connect
   * to the "next address" in the Curl_hostaddr structure that we resolved
   * before. But we don't have that struct around anymore and we can't just
   * keep a pointer since the cache might in fact have gotten pruned by the
   * time we want to read this... Alas, we don't do this yet.
   */

  return CURLE_OK;
}

static void Curl_setNoDelay(struct connectdata *conn,
                            curl_socket_t sockfd)
{
#ifdef TCP_NODELAY
  struct SessionHandle *data= conn->data;
  socklen_t onoff = (socklen_t) data->set.tcp_nodelay;
  if(setsockopt(sockfd, IPPROTO_TCP, TCP_NODELAY, (void *)&onoff,
                sizeof(onoff)) < 0)
    infof(data, "Could not set TCP_NODELAY: %s\n",
          Curl_strerror(conn, Curl_ourerrno()));
  else
    infof(data,"TCP_NODELAY set\n");
#else
  (void)conn;
  (void)sockfd;
#endif
}

/*
 * TCP connect to the given host with timeout, proxy or remote doesn't matter.
 * There might be more than one IP address to try out. Fill in the passed
 * pointer with the connected socket.
 */

CURLcode Curl_connecthost(struct connectdata *conn,  /* context */
                          struct Curl_dns_entry *remotehost, /* use this one */
                          int port,                  /* connect to this */
                          curl_socket_t *sockconn,   /* the connected socket */
                          Curl_ipconnect **addr,     /* the one we used */
                          bool *connected)           /* really connected? */
{
  struct SessionHandle *data = conn->data;
  int rc, error;
  curl_socket_t sockfd= CURL_SOCKET_BAD;
  int aliasindex=0;
  char *hostname;

  struct timeval after;
  struct timeval before = Curl_tvnow();

#ifdef ENABLE_IPV6
  struct addrinfo *ai;
#endif

  /*************************************************************
   * Figure out what maximum time we have left
   *************************************************************/
  long timeout_ms=300000; /* milliseconds, default to five minutes */

  *connected = FALSE; /* default to not connected */

  if(data->set.timeout || data->set.connecttimeout) {
    double has_passed;

    /* Evaluate in milliseconds how much time that has passed */
    has_passed = Curl_tvdiff(Curl_tvnow(), data->progress.start);

#ifndef min
#define min(a, b)   ((a) < (b) ? (a) : (b))
#endif

    /* get the most strict timeout of the ones converted to milliseconds */
    if(data->set.timeout && data->set.connecttimeout) {
      if (data->set.timeout < data->set.connecttimeout)
        timeout_ms = data->set.timeout*1000;
      else
        timeout_ms = data->set.connecttimeout*1000;
    }
    else if(data->set.timeout)
      timeout_ms = data->set.timeout*1000;
    else
      timeout_ms = data->set.connecttimeout*1000;

    /* subtract the passed time */
    timeout_ms -= (long)has_passed;

    if(timeout_ms < 0) {
      /* a precaution, no need to continue if time already is up */
      failf(data, "Connection time-out");
      return CURLE_OPERATION_TIMEOUTED;
    }
  }

  hostname = data->change.proxy?conn->proxy.name:conn->host.name;
  infof(data, "About to connect() to %s port %d\n",
        hostname, port);

#ifdef ENABLE_IPV6
  /*
   * Connecting with a getaddrinfo chain
   */
  for (ai = remotehost->addr; ai; ai = ai->ai_next, aliasindex++) {
    sockfd = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
    if (sockfd == CURL_SOCKET_BAD)
      continue;

    else if(data->set.tcp_nodelay)
      Curl_setNoDelay(conn, sockfd);
#else
  /*
   * Connecting with old style IPv4-only support
   */

  /* This is the loop that attempts to connect to all IP-addresses we
     know for the given host. One by one. */
  for(rc=-1, aliasindex=0;
      rc && (struct in_addr *)remotehost->addr->h_addr_list[aliasindex];
      aliasindex++) {
    struct sockaddr_in serv_addr;

    /* create an IPv4 TCP socket */
    sockfd = socket(AF_INET, SOCK_STREAM, 0);
    if(CURL_SOCKET_BAD == sockfd) {
      failf(data, "couldn't create socket");
      return CURLE_COULDNT_CONNECT; /* big time error */
    }

    else if(data->set.tcp_nodelay)
      Curl_setNoDelay(conn, sockfd);

    /* nasty address work before connect can be made */
    memset((char *) &serv_addr, '\0', sizeof(serv_addr));
    memcpy((char *)&(serv_addr.sin_addr),
           (struct in_addr *)remotehost->addr->h_addr_list[aliasindex],
           sizeof(struct in_addr));
    serv_addr.sin_family = remotehost->addr->h_addrtype;
    serv_addr.sin_port = htons((unsigned short)port);
#endif

    if(conn->data->set.device) {
      /* user selected to bind the outgoing socket to a specified "device"
         before doing connect */
      CURLcode res = bindlocal(conn, sockfd);
      if(res)
        return res;
    }

    /* set socket non-blocking */
    Curl_nonblock(sockfd, TRUE);

    /* do not use #ifdef within the function arguments below, as connect() is
       a defined macro on some platforms and some compilers don't like to mix
       #ifdefs with macro usage! (AmigaOS is one such platform) */
#ifdef ENABLE_IPV6
    rc = connect(sockfd, ai->ai_addr, ai->ai_addrlen);
#else
    rc = connect(sockfd, (struct sockaddr *)&serv_addr, sizeof(serv_addr));
#endif

    if(-1 == rc) {
      error = Curl_ourerrno();

      switch (error) {
      case EINPROGRESS:
      case EWOULDBLOCK:
#if defined(EAGAIN) && EAGAIN != EWOULDBLOCK
        /* On some platforms EAGAIN and EWOULDBLOCK are the
         * same value, and on others they are different, hence
         * the odd #if
         */
      case EAGAIN:
#endif
        /* asynchronous connect, wait for connect or timeout */
        if(data->state.used_interface == Curl_if_multi)
          /* don't hang when doing multi */
          timeout_ms = 0;

        rc = waitconnect(sockfd, timeout_ms);
        break;
      default:
        /* unknown error, fallthrough and try another address! */
        failf(data, "Failed to connect to %s IP number %d: %s",
              hostname, aliasindex+1, Curl_strerror(conn,error));
        break;
      }
    }

    /* The '1 == rc' comes from the waitconnect(), and not from connect().
       We can be sure of this since connect() cannot return 1. */
    if((1 == rc) && (data->state.used_interface == Curl_if_multi)) {
      /* Timeout when running the multi interface, we return here with a
         CURLE_OK return code. */
      rc = 0;
      break;
    }

    if(0 == rc) {
      if (verifyconnect(sockfd,NULL)) {
        /* we are connected, awesome! */
        *connected = TRUE; /* this is a true connect */
        break;
      }
      /* nope, not connected for real */
      rc = -1;
    }
    else
      verifyconnect(sockfd,&error);    /* get non-blocking error */

    /* connect failed or timed out */
    sclose(sockfd);
    sockfd = CURL_SOCKET_BAD;

    /* get a new timeout for next attempt */
    after = Curl_tvnow();
    timeout_ms -= Curl_tvdiff(after, before);
    if(timeout_ms < 0) {
      failf(data, "connect() timed out!");
      return CURLE_OPERATION_TIMEOUTED;
    }
    before = after;
  }
  if (sockfd == CURL_SOCKET_BAD) {
    /* no good connect was made */
    *sockconn = -1;
    failf(data, "Connect failed; %s", Curl_strerror(conn,error));
    return CURLE_COULDNT_CONNECT;
  }

  /* leave the socket in non-blocking mode */

  /* store the address we use */
  if(addr) {
#ifdef ENABLE_IPV6
    *addr = ai;
#else
    *addr = (struct in_addr *)remotehost->addr->h_addr_list[aliasindex];
#endif
  }

  /* allow NULL-pointers to get passed in */
  if(sockconn)
    *sockconn = sockfd;    /* the socket descriptor we've connected */

  return CURLE_OK;
}