summaryrefslogtreecommitdiff
path: root/ext/socket/extconf.rb
blob: 0cc8a88d5ca8b0764a302e348d7f8ec616bae635 (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
# frozen_string_literal: false
require 'mkmf'

AF_INET6_SOCKET_CREATION_TEST = <<EOF
#include <sys/types.h>
#ifndef _WIN32
#include <sys/socket.h>
#endif
int
main(void)
{
  socket(AF_INET6, SOCK_STREAM, 0);
  return 0;
}
EOF

GETADDRINFO_GETNAMEINFO_TEST = <<EOF
#include <stdlib.h>

#ifndef EXIT_SUCCESS
#define EXIT_SUCCESS 0
#endif
#ifndef EXIT_FAILURE
#define EXIT_FAILURE 1
#endif

#ifndef AF_LOCAL
#define AF_LOCAL AF_UNIX
#endif

int
main(void)
{
  int passive, gaierr, inet4 = 0, inet6 = 0;
  struct addrinfo hints, *ai, *aitop;
  char straddr[INET6_ADDRSTRLEN], strport[16];
#ifdef _WIN32
  WSADATA retdata;

  WSAStartup(MAKEWORD(2, 0), &retdata);
#endif

  for (passive = 0; passive <= 1; passive++) {
    memset(&hints, 0, sizeof(hints));
    hints.ai_family = AF_UNSPEC;
    hints.ai_protocol = IPPROTO_TCP;
    hints.ai_flags = passive ? AI_PASSIVE : 0;
    hints.ai_socktype = SOCK_STREAM;
    if ((gaierr = getaddrinfo(NULL, "54321", &hints, &aitop)) != 0) {
      (void)gai_strerror(gaierr);
      goto bad;
    }
    for (ai = aitop; ai; ai = ai->ai_next) {
      if (ai->ai_family == AF_LOCAL) continue;
      if (ai->ai_addr == NULL)
        goto bad;
#if defined(_AIX)
      if (ai->ai_family == AF_INET6 && passive) {
        inet6++;
        continue;
      }
      ai->ai_addr->sa_len = ai->ai_addrlen;
      ai->ai_addr->sa_family = ai->ai_family;
#endif
      if (ai->ai_addrlen == 0 ||
          getnameinfo(ai->ai_addr, ai->ai_addrlen,
                      straddr, sizeof(straddr), strport, sizeof(strport),
                      NI_NUMERICHOST|NI_NUMERICSERV) != 0) {
        goto bad;
      }
      if (strcmp(strport, "54321") != 0) {
        goto bad;
      }
      switch (ai->ai_family) {
      case AF_INET:
        if (passive) {
          if (strcmp(straddr, "0.0.0.0") != 0) {
            goto bad;
          }
        } else {
          if (strcmp(straddr, "127.0.0.1") != 0) {
            goto bad;
          }
        }
        inet4++;
        break;
      case AF_INET6:
        if (passive) {
          if (strcmp(straddr, "::") != 0) {
            goto bad;
          }
        } else {
          if (strcmp(straddr, "::1") != 0) {
            goto bad;
          }
        }
        inet6++;
        break;
      case AF_UNSPEC:
        goto bad;
        break;
      default:
        /* another family support? */
        break;
      }
    }
  }

  if (!(inet4 == 0 || inet4 == 2))
    goto bad;
  if (!(inet6 == 0 || inet6 == 2))
    goto bad;

  if (aitop)
    freeaddrinfo(aitop);
  return EXIT_SUCCESS;

 bad:
  if (aitop)
    freeaddrinfo(aitop);
  return EXIT_FAILURE;
}
EOF

RECVMSG_WITH_MSG_PEEK_ALLOCATE_FD_TEST = <<'EOF'
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/socket.h>
#include <sys/un.h>
#include <unistd.h>

int main(int argc, char *argv[])
{
    int ps[2], sv[2];
    int ret;
    ssize_t ss;
    int s_fd, r_fd;
    struct msghdr s_msg, r_msg;
    union {
        struct cmsghdr hdr;
        char dummy[CMSG_SPACE(sizeof(int))];
    } s_cmsg, r_cmsg;
    struct iovec s_iov, r_iov;
    char s_buf[1], r_buf[1];
    struct stat s_statbuf, r_statbuf;

    ret = pipe(ps);
    if (ret == -1) { perror("pipe"); exit(EXIT_FAILURE); }

    s_fd = ps[0];

    ret = socketpair(AF_UNIX, SOCK_DGRAM, 0, sv);
    if (ret == -1) { perror("socketpair"); exit(EXIT_FAILURE); }

    s_msg.msg_name = NULL;
    s_msg.msg_namelen = 0;
    s_msg.msg_iov = &s_iov;
    s_msg.msg_iovlen = 1;
    s_msg.msg_control = &s_cmsg;
    s_msg.msg_controllen = CMSG_SPACE(sizeof(int));;
    s_msg.msg_flags = 0;

    s_iov.iov_base = &s_buf;
    s_iov.iov_len = sizeof(s_buf);

    s_buf[0] = 'a';

    s_cmsg.hdr.cmsg_len = CMSG_LEN(sizeof(int));
    s_cmsg.hdr.cmsg_level = SOL_SOCKET;
    s_cmsg.hdr.cmsg_type = SCM_RIGHTS;
    memcpy(CMSG_DATA(&s_cmsg.hdr), (char *)&s_fd, sizeof(int));

    ss = sendmsg(sv[0], &s_msg, 0);
    if (ss == -1) { perror("sendmsg"); exit(EXIT_FAILURE); }

    r_msg.msg_name = NULL;
    r_msg.msg_namelen = 0;
    r_msg.msg_iov = &r_iov;
    r_msg.msg_iovlen = 1;
    r_msg.msg_control = &r_cmsg;
    r_msg.msg_controllen = CMSG_SPACE(sizeof(int));
    r_msg.msg_flags = 0;

    r_iov.iov_base = &r_buf;
    r_iov.iov_len = sizeof(r_buf);

    r_buf[0] = '0';

    memset(&r_cmsg, 0xff, CMSG_SPACE(sizeof(int)));

    ss = recvmsg(sv[1], &r_msg, MSG_PEEK);
    if (ss == -1) { perror("recvmsg"); exit(EXIT_FAILURE); }

    if (ss != 1) {
        fprintf(stderr, "unexpected return value from recvmsg: %ld\n", (long)ss);
        exit(EXIT_FAILURE);
    }
    if (r_buf[0] != 'a') {
        fprintf(stderr, "unexpected return data from recvmsg: 0x%02x\n", r_buf[0]);
        exit(EXIT_FAILURE);
    }

    if (r_msg.msg_controllen < CMSG_LEN(sizeof(int))) {
        fprintf(stderr, "unexpected: r_msg.msg_controllen < CMSG_LEN(sizeof(int)) not hold: %ld\n",
                (long)r_msg.msg_controllen);
        exit(EXIT_FAILURE);
    }
    if (r_cmsg.hdr.cmsg_len < CMSG_LEN(sizeof(int))) {
        fprintf(stderr, "unexpected: r_cmsg.hdr.cmsg_len < CMSG_LEN(sizeof(int)) not hold: %ld\n",
                (long)r_cmsg.hdr.cmsg_len);
        exit(EXIT_FAILURE);
    }
    memcpy((char *)&r_fd, CMSG_DATA(&r_cmsg.hdr), sizeof(int));

    if (r_fd < 0) {
        fprintf(stderr, "negative r_fd: %d\n", r_fd);
        exit(EXIT_FAILURE);
    }

    if (r_fd == s_fd) {
        fprintf(stderr, "r_fd and s_fd is same: %d\n", r_fd);
        exit(EXIT_FAILURE);
    }

    ret = fstat(s_fd, &s_statbuf);
    if (ret == -1) { perror("fstat(s_fd)"); exit(EXIT_FAILURE); }

    ret = fstat(r_fd, &r_statbuf);
    if (ret == -1) { perror("fstat(r_fd)"); exit(EXIT_FAILURE); }

    if (s_statbuf.st_dev != r_statbuf.st_dev ||
        s_statbuf.st_ino != r_statbuf.st_ino) {
        fprintf(stderr, "dev/ino doesn't match: s_fd:%ld/%ld r_fd:%ld/%ld\n",
                (long)s_statbuf.st_dev, (long)s_statbuf.st_ino,
                (long)r_statbuf.st_dev, (long)r_statbuf.st_ino);
        exit(EXIT_FAILURE);
    }

    return EXIT_SUCCESS;
}
EOF

def test_recvmsg_with_msg_peek_creates_fds(headers)
  case RUBY_PLATFORM
  when /linux/
    # Linux 2.6.38 allocate fds by recvmsg with MSG_PEEK.
    close_fds = true
  when /bsd|darwin/
    # FreeBSD 8.2.0, NetBSD 5 and MacOS X Snow Leopard doesn't
    # allocate fds by recvmsg with MSG_PEEK.
    # [ruby-dev:44189]
    # http://bugs.ruby-lang.org/issues/5075
    close_fds = false
  when /cygwin/
    # Cygwin doesn't support fd passing.
    # http://cygwin.com/ml/cygwin/2003-09/msg01808.html
    close_fds = false
  else
    close_fds = nil
  end
  if !CROSS_COMPILING
    if checking_for("recvmsg() with MSG_PEEK allocate file descriptors") {
        try_run(cpp_include(headers) + RECVMSG_WITH_MSG_PEEK_ALLOCATE_FD_TEST)
       }
      if close_fds == false
        warn "unexpected fd-passing recvmsg() with MSG_PEEK behavor on #{RUBY_PLATFORM}: fd allocation unexpected."
      elsif close_fds == nil
        puts "info: #{RUBY_PLATFORM} recvmsg() with MSG_PEEK allocates fds on fd-passing."
      end
      close_fds = true
    else
      if close_fds == true
        warn "unexpected fd-passing recvmsg() with MSG_PEEK behavor on #{RUBY_PLATFORM}: fd allocation expected."
      elsif close_fds == nil
        puts "info: #{RUBY_PLATFORM}: recvmsg() with MSG_PEEK doesn't allocates fds on fd-passing."
      end
      close_fds = false
    end
  end
  if close_fds == nil
    abort <<EOS
Fatal: cannot test fd-passing recvmsg() with MSG_PEEK behavor
because cross-compilation for #{RUBY_PLATFORM}.
If recvmsg() with MSG_PEEK allocates fds on fd passing:
--enable-close-fds-by-recvmsg-with-peek
If recvmsg() with MSG_PEEK doesn't allocate fds on fd passing:
--disable-close-fds-by-recvmsg-with-peek
EOS
  end
  close_fds
end

$INCFLAGS << " -I$(topdir) -I$(top_srcdir)"

if /darwin/ =~ RUBY_PLATFORM
  # For IPv6 extension header access on OS X 10.7+ [Bug #8517]
  $CFLAGS << " -D__APPLE_USE_RFC_3542"
end

headers = []
unless $mswin or $mingw
  headers = %w<sys/types.h netdb.h string.h sys/socket.h netinet/in.h>
end

%w[
  sys/uio.h
  xti.h
  netinet/in_systm.h
  netinet/tcp.h
  netinet/tcp_fsm.h
  netinet/udp.h
  arpa/inet.h
  netpacket/packet.h
  net/ethernet.h
  sys/un.h
  ifaddrs.h
  sys/ioctl.h
  sys/sockio.h
  net/if.h
  sys/param.h
  sys/ucred.h
  ucred.h
  net/if_dl.h
  arpa/nameser.h
  resolv.h
].each {|h|
  if have_header(h, headers)
    headers << h
  end
}

have_struct_member("struct sockaddr", "sa_len", headers) # 4.4BSD
have_struct_member("struct sockaddr_in", "sin_len", headers) # 4.4BSD
have_struct_member("struct sockaddr_in6", "sin6_len", headers) # 4.4BSD

if have_type("struct sockaddr_un", headers) # POSIX
  have_struct_member("struct sockaddr_un", "sun_len", headers) # 4.4BSD
end

have_type("struct sockaddr_dl", headers) # AF_LINK address.  4.4BSD since Net2

have_type("struct sockaddr_storage", headers)

have_type("struct addrinfo", headers)

if have_type("socklen_t", headers)
  if try_static_assert("sizeof(socklen_t) >= sizeof(long)", headers)
    $defs << "-DRSTRING_SOCKLEN=(socklen_t)RSTRING_LEN"
  end
end

have_type("struct in_pktinfo", headers) {|src|
  src.sub(%r'^/\*top\*/', '\&'"\n#if defined(IPPROTO_IP) && defined(IP_PKTINFO)") <<
  "#else\n" << "#error\n" << ">>>>>> no in_pktinfo <<<<<<\n" << "#endif\n"
} and have_struct_member("struct in_pktinfo", "ipi_spec_dst", headers)
have_type("struct in6_pktinfo", headers) {|src|
  src.sub(%r'^/\*top\*/', '\&'"\n#if defined(IPPROTO_IPV6) && defined(IPV6_PKTINFO)") <<
  "#else\n" << "#error\n" << ">>>>>> no in6_pktinfo <<<<<<\n" << "#endif\n"
}

have_type("struct sockcred", headers)
have_type("struct cmsgcred", headers)

have_type("struct ip_mreq", headers) # 4.4BSD
have_type("struct ip_mreqn", headers) # Linux 2.4
have_type("struct ipv6_mreq", headers) # RFC 3493

have_msg_control = nil
have_msg_control = have_struct_member('struct msghdr', 'msg_control', headers) unless $mswin or $mingw
have_struct_member('struct msghdr', 'msg_accrights', headers)

if have_type("struct tcp_info", headers)
  have_const("TCP_ESTABLISHED", headers)
  have_const("TCP_SYN_SENT", headers)
  have_const("TCP_SYN_RECV", headers)
  have_const("TCP_FIN_WAIT1", headers)
  have_const("TCP_FIN_WAIT2", headers)
  have_const("TCP_TIME_WAIT", headers)
  have_const("TCP_CLOSE", headers)
  have_const("TCP_CLOSE_WAIT", headers)
  have_const("TCP_LAST_ACK", headers)
  have_const("TCP_LISTEN", headers)
  have_const("TCP_CLOSING", headers)
  have_struct_member('struct tcp_info', 'tcpi_state', headers)
  if /solaris/ !~ RUBY_PLATFORM
    have_struct_member('struct tcp_info', 'tcpi_ca_state', headers)
  end
  have_struct_member('struct tcp_info', 'tcpi_retransmits', headers)
  have_struct_member('struct tcp_info', 'tcpi_probes', headers)
  have_struct_member('struct tcp_info', 'tcpi_backoff', headers)
  have_struct_member('struct tcp_info', 'tcpi_options', headers)
  have_struct_member('struct tcp_info', 'tcpi_snd_wscale', headers)
  have_struct_member('struct tcp_info', 'tcpi_rcv_wscale', headers)
  have_struct_member('struct tcp_info', 'tcpi_rto', headers)
  have_struct_member('struct tcp_info', 'tcpi_ato', headers)
  have_struct_member('struct tcp_info', 'tcpi_snd_mss', headers)
  have_struct_member('struct tcp_info', 'tcpi_rcv_mss', headers)
  have_struct_member('struct tcp_info', 'tcpi_unacked', headers)
  have_struct_member('struct tcp_info', 'tcpi_sacked', headers)
  have_struct_member('struct tcp_info', 'tcpi_lost', headers)
  have_struct_member('struct tcp_info', 'tcpi_retrans', headers)
  have_struct_member('struct tcp_info', 'tcpi_fackets', headers)
  have_struct_member('struct tcp_info', 'tcpi_last_data_sent', headers)
  have_struct_member('struct tcp_info', 'tcpi_last_ack_sent', headers)
  have_struct_member('struct tcp_info', 'tcpi_last_data_recv', headers)
  have_struct_member('struct tcp_info', 'tcpi_last_ack_recv', headers)
  have_struct_member('struct tcp_info', 'tcpi_pmtu', headers)
  have_struct_member('struct tcp_info', 'tcpi_rcv_ssthresh', headers)
  have_struct_member('struct tcp_info', 'tcpi_rtt', headers)
  have_struct_member('struct tcp_info', 'tcpi_rttvar', headers)
  have_struct_member('struct tcp_info', 'tcpi_snd_ssthresh', headers)
  have_struct_member('struct tcp_info', 'tcpi_snd_cwnd', headers)
  have_struct_member('struct tcp_info', 'tcpi_advmss', headers)
  have_struct_member('struct tcp_info', 'tcpi_reordering', headers)
  have_struct_member('struct tcp_info', 'tcpi_rcv_rtt', headers)
  have_struct_member('struct tcp_info', 'tcpi_rcv_space', headers)
  have_struct_member('struct tcp_info', 'tcpi_total_retrans', headers)

  # FreeBSD extension
  have_struct_member('struct tcp_info', 'tcpi_snd_wnd', headers)
  have_struct_member('struct tcp_info', 'tcpi_snd_bwnd', headers)
  have_struct_member('struct tcp_info', 'tcpi_snd_nxt', headers)
  have_struct_member('struct tcp_info', 'tcpi_rcv_nxt', headers)
  have_struct_member('struct tcp_info', 'tcpi_toe_tid', headers)
  have_struct_member('struct tcp_info', 'tcpi_snd_rexmitpack', headers)
  have_struct_member('struct tcp_info', 'tcpi_rcv_ooopack', headers)
  have_struct_member('struct tcp_info', 'tcpi_snd_zerowin', headers)
end

case RUBY_PLATFORM
when /mswin(32|64)|mingw/
  test_func = "WSACleanup"
  have_library("iphlpapi")
  have_library("ws2_32", "WSACleanup", headers)
when /cygwin/
  test_func = "socket(0,0,0)"
when /haiku/
  test_func = "socket(0,0,0)"
  have_library("network", "socket(0,0,0)", headers)
else
  test_func = "socket(0,0,0)"
  have_library("nsl", 't_open("", 0, (struct t_info *)NULL)', headers) # SunOS
  have_library("socket", "socket(0,0,0)", headers) # SunOS
end

if have_func(test_func, headers)

  have_func("sendmsg(0, (struct msghdr *)NULL, 0)", headers) # POSIX
  have_recvmsg = have_func("recvmsg(0, (struct msghdr *)NULL, 0)", headers) # POSIX

  have_func("freehostent((struct hostent *)NULL)", headers) # RFC 2553
  have_func("freeaddrinfo((struct addrinfo *)NULL)", headers) # RFC 2553

  if /haiku/ !~ RUBY_PLATFORM and
     have_func("gai_strerror(0)", headers) # POSIX
    if checking_for("gai_strerror() returns const pointer") {!try_compile(<<EOF)}
#{cpp_include(headers)}
#include <stdlib.h>
void
conftest_gai_strerror_is_const()
{
    *gai_strerror(0) = 0;
}
EOF
      $defs << "-DGAI_STRERROR_CONST"
    end
  end

  have_func("accept4", headers)

  have_func('inet_ntop(0, (const void *)0, (char *)0, 0)', headers) or
    have_func("inet_ntoa(*(struct in_addr *)NULL)", headers)
  have_func('inet_pton(0, "", (void *)0)', headers) or
    have_func('inet_aton("", (struct in_addr *)0)', headers)
  have_func('getservbyport(0, "")', headers)
  have_func("getifaddrs((struct ifaddrs **)NULL)", headers)
  have_struct_member("struct if_data", "ifi_vhid", headers) # FreeBSD

  have_func("getpeereid", headers)

  have_func("getpeerucred(0, (ucred_t **)NULL)", headers) # SunOS

  have_func_decl = proc do |name, headers|
    if !checking_for("declaration of #{name}()") {!%w[int void].all? {|ret| try_compile(<<EOF)}}
#{cpp_include(headers)}
#{ret} #{name}(void);
EOF
      $defs << "-DNEED_#{name.tr_cpp}_DECL"
    end
  end
  if have_func('if_indextoname(0, "")', headers)
    have_func_decl["if_indextoname"]
  end
  if have_func('if_nametoindex("")', headers)
    have_func_decl["if_nametoindex"]
  end

  have_func("hsterror", headers)
  have_func('getipnodebyname("", 0, 0, (int *)0)', headers) # RFC 2553
  have_func('gethostbyname2("", 0)', headers) # RFC 2133
  have_func("socketpair(0, 0, 0, 0)", headers)
  unless have_func("gethostname((char *)0, 0)", headers)
    have_func("uname((struct utsname *)NULL)", headers)
  end

  ipv6 = false
  default_ipv6 = /haiku/ !~ RUBY_PLATFORM
  if enable_config("ipv6", default_ipv6)
    if checking_for("ipv6") {try_link(AF_INET6_SOCKET_CREATION_TEST)}
      $defs << "-DENABLE_IPV6" << "-DINET6"
      ipv6 = true
    end
  end

  if ipv6
    if $mingw
      $CPPFLAGS << " -D_WIN32_WINNT=0x501" unless $CPPFLAGS.include?("_WIN32_WINNT")
    end
    ipv6lib = nil
    class << (fmt = "unknown")
      def %(s) s || self end
    end
    idirs, ldirs = dir_config("inet6", %w[/usr/inet6 /usr/local/v6].find {|d| File.directory?(d)})
    checking_for("ipv6 type", fmt) do
      if have_macro("IPV6_INRIA_VERSION", "netinet/in.h")
        "inria"
      elsif have_macro("__KAME__", "netinet/in.h")
        have_library(ipv6lib = "inet6")
        "kame"
      elsif have_macro("_TOSHIBA_INET6", "sys/param.h")
        have_library(ipv6lib = "inet6") and "toshiba"
      elsif have_macro("__V6D__", "sys/v6config.h")
        have_library(ipv6lib = "v6") and "v6d"
      elsif have_macro("_ZETA_MINAMI_INET6", "sys/param.h")
        have_library(ipv6lib = "inet6") and "zeta"
      elsif have_library("inet6")
        "inet6"
      end
    end or not ipv6lib or abort <<EOS

Fatal: no #{ipv6lib} library found.  cannot continue.
You need to fetch lib#{ipv6lib}.a from appropriate
ipv6 kit and compile beforehand.
EOS
  end

  if !have_macro("IPPROTO_IPV6", headers) && have_const("IPPROTO_IPV6", headers)
    IO.read(File.join(File.dirname(__FILE__), "mkconstants.rb")).sub(/\A.*^__END__$/m, '').split(/\r?\n/).grep(/\AIPPROTO_\w*/){$&}.each {|name|
      have_const(name, headers) unless $defs.include?("-DHAVE_CONST_#{name.upcase}")
    }
  end

  if enable_config("close-fds-by-recvmsg-with-peek") {
      have_msg_control && have_recvmsg &&
      have_const('AF_UNIX', headers) && have_const('SCM_RIGHTS', headers) &&
      test_recvmsg_with_msg_peek_creates_fds(headers)
     }
    $defs << "-DFD_PASSING_WORK_WITH_RECVMSG_MSG_PEEK"
  end

  case enable_config("wide-getaddrinfo")
  when true
    getaddr_info_ok = :wide
  when nil, false
    getaddr_info_ok = (:wide if getaddr_info_ok.nil?)
    if have_func("getnameinfo", headers) and have_func("getaddrinfo", headers)
      if CROSS_COMPILING ||
         $mingw || $mswin ||
         checking_for("system getaddrinfo working") {
           try_run(cpp_include(headers) + GETADDRINFO_GETNAMEINFO_TEST)
         }
        getaddr_info_ok = :os
      end
    end
  else
    raise "unexpected enable_config() value"
  end

  if ipv6 and not getaddr_info_ok
    abort <<EOS

Fatal: --enable-ipv6 is specified, and your OS seems to support IPv6 feature.
But your getaddrinfo() and getnameinfo() are appeared to be broken.  Sorry,
you cannot compile IPv6 socket classes with broken these functions.
You can try --enable-wide-getaddrinfo.
EOS
  end

  case with_config("lookup-order-hack", "UNSPEC")
  when "INET"
    $defs << "-DLOOKUP_ORDER_HACK_INET"
  when "INET6"
    $defs << "-DLOOKUP_ORDER_HACK_INET6"
  when "UNSPEC"
    # nothing special
  else
    abort <<EOS

Fatal: invalid value for --with-lookup-order-hack (expected INET, INET6 or UNSPEC)
EOS
  end

  $objs = [
    "init.#{$OBJEXT}",
    "constants.#{$OBJEXT}",
    "basicsocket.#{$OBJEXT}",
    "socket.#{$OBJEXT}",
    "ipsocket.#{$OBJEXT}",
    "tcpsocket.#{$OBJEXT}",
    "tcpserver.#{$OBJEXT}",
    "sockssocket.#{$OBJEXT}",
    "udpsocket.#{$OBJEXT}",
    "unixsocket.#{$OBJEXT}",
    "unixserver.#{$OBJEXT}",
    "option.#{$OBJEXT}",
    "ancdata.#{$OBJEXT}",
    "raddrinfo.#{$OBJEXT}",
    "ifaddr.#{$OBJEXT}"
  ]

  if getaddr_info_ok == :wide
    if !have_type("struct in6_addr", headers) and have_type("struct in_addr6", headers)
      $defs.pop(2)
      $defs << "-Din_addr6=in6_addr"
    end
    if have_struct_member("struct in6_addr", "s6_addr8", headers)
      $defs[-1] = "-Ds6_addr=s6_addr8"
    end
    if ipv6 == "kame" && have_struct_member("struct in6_addr", "s6_addr32", headers)
      $defs[-1] = "-DFAITH"
    end
    $CPPFLAGS="-I. "+$CPPFLAGS
    $objs += ["getaddrinfo.#{$OBJEXT}"]
    $objs += ["getnameinfo.#{$OBJEXT}"]
    $defs << "-DGETADDRINFO_EMU"
  end

  # workaround for recent Windows SDK
  $defs << "-DIPPROTO_IPV6=IPPROTO_IPV6" if $defs.include?("-DHAVE_CONST_IPPROTO_IPV6") && !have_macro("IPPROTO_IPV6")

  $distcleanfiles << "constants.h" << "constdefs.*"

  if enable_config("socks", ENV["SOCKS_SERVER"])
    if have_library("socks5", "SOCKSinit")
      $defs << "-DSOCKS5" << "-DSOCKS"
    elsif have_library("socks", "Rconnect")
      $defs << "-DSOCKS"
    end
  end

  hdr = "netinet6/in6.h"
  if /darwin/ =~ RUBY_PLATFORM and !try_compile(<<"SRC", nil, :werror=>true)
#include <netinet/in.h>
int t(struct in6_addr *addr) {return IN6_IS_ADDR_UNSPECIFIED(addr);}
SRC
    print "fixing apple's netinet6/in6.h ..."; $stdout.flush
    in6 = File.read("/usr/include/#{hdr}")
    if in6.gsub!(/\*\(const\s+__uint32_t\s+\*\)\(const\s+void\s+\*\)\(&(\(\w+\))->s6_addr\[(\d+)\]\)/) do
        i, r = $2.to_i.divmod(4)
        if r.zero?
          "#$1->__u6_addr.__u6_addr32[#{i}]"
        else
          $&
        end
      end
      FileUtils.mkdir_p(File.dirname(hdr))
      open(hdr, "w") {|f| f.write(in6)}
      $distcleanfiles << hdr
      $distcleandirs << File.dirname(hdr)
      puts "done"
    else
      puts "not needed"
    end
  end
  create_makefile("socket")
end