src/ip/tools.cc

   1 /*
   2  * Copyright (C) 1996-2017 The Squid Software Foundation and contributors
   3  *
   4  * Squid software is distributed under GPLv2+ license and includes
   5  * contributions from numerous individuals and organizations.
   6  * Please see the COPYING and CONTRIBUTORS files for details.
   7  */
   8
   9 /* DEBUG: section 21    Misc Functions */
  10
  11 #include "squid.h"
  12 #include "Debug.h"
  13 #include "ip/tools.h"
  14
  15 #if HAVE_UNISTD_H
  16 #include <unistd.h>
  17 #endif
  18 #if HAVE_SYS_SOCKET_H
  19 #include <sys/socket.h>
  20 #endif
  21 #if HAVE_NETINET_IN_H
  22 #include <netinet/in.h>
  23 #endif
  24 #if HAVE_NETINET_IN6_H
  25 #include <netinet/in6.h>
  26 #endif
  27
  28 int Ip::EnableIpv6 = IPV6_OFF;
  29
  30 void
  31 Ip::ProbeTransport()
  32 {
  33     // check for usable IPv6 sockets
  34     int s = socket(PF_INET6, SOCK_STREAM, 0);
  35     if (s < 0) {
  36         debugs(3, 2, "IPv6 not supported on this machine. Auto-Disabled.");
  37         EnableIpv6 = IPV6_OFF;
  38         return;
  39     }
  40
  41     // Test for v4-mapping capability
  42     // (AKA. the operating system supports RFC 3493 section 5.3)
  43 #if defined(IPV6_V6ONLY)
  44     int tos = 0;
  45     if (setsockopt(s, IPPROTO_IPV6, IPV6_V6ONLY, (char *) &tos, sizeof(int)) == 0) {
  46         debugs(3, 2, "Detected IPv6 hybrid or v4-mapping stack...");
  47         EnableIpv6 |= IPV6_SPECIAL_V4MAPPING;
  48     } else {
  49         debugs(3, 2, "Detected split IPv4 and IPv6 stacks ...");
  50         EnableIpv6 |= IPV6_SPECIAL_SPLITSTACK;
  51     }
  52 #else
  53     // compliance here means they at least supply the option for compilers building code
  54     // even if possibly to return hard-coded -1 on use.
  55     debugs(3, 2, "Missing RFC 3493 compliance - attempting split IPv4 and IPv6 stacks ...");
  56     EnableIpv6 |= IPV6_SPECIAL_SPLITSTACK;
  57 #endif
  58     // TODO: attempt to use the socket to connect somewhere ?
  59     //  needs to be safe to contact and with guaranteed working IPv6 at the other end.
  60     close(s);
  61
  62 #if USE_IPV6
  63     debugs(3, 2, "IPv6 transport " << (EnableIpv6?"Enabled":"Disabled"));
  64 #else
  65     debugs(3, 2, "IPv6 transport " << (EnableIpv6?"Available":"Disabled"));
  66     if (EnableIpv6 != IPV6_OFF) {
  67         debugs(3, DBG_CRITICAL, "WARNING: BCP 177 violation. IPv6 transport forced OFF by build parameters.");
  68         EnableIpv6 = IPV6_OFF;
  69     }
  70 #endif
  71 }
  72