src/ip/tools.cc

   1 /*
   2  * Copyright (C) 1996-2021 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/Address.h"
  14 #include "ip/tools.h"
  15
  16 #if HAVE_UNISTD_H
  17 #include <unistd.h>
  18 #endif
  19 #if HAVE_SYS_SOCKET_H
  20 #include <sys/socket.h>
  21 #endif
  22 #if HAVE_NETINET_IN_H
  23 #include <netinet/in.h>
  24 #endif
  25 #if HAVE_NETINET_IN6_H
  26 #include <netinet/in6.h>
  27 #endif
  28
  29 int Ip::EnableIpv6 = IPV6_OFF;
  30
  31 void
  32 Ip::ProbeTransport()
  33 {
  34     // check for usable IPv6 sockets
  35     int s = socket(PF_INET6, SOCK_STREAM, 0);
  36     if (s < 0) {
  37         debugs(3, 2, "IPv6 not supported on this machine. Auto-Disabled.");
  38         EnableIpv6 = IPV6_OFF;
  39         return;
  40     }
  41
  42     // Test for v4-mapping capability
  43     // (AKA. the operating system supports RFC 3493 section 5.3)
  44 #if defined(IPV6_V6ONLY)
  45     int tos = 0;
  46     if (setsockopt(s, IPPROTO_IPV6, IPV6_V6ONLY, (char *) &tos, sizeof(int)) == 0) {
  47         debugs(3, 2, "Detected IPv6 hybrid or v4-mapping stack...");
  48         EnableIpv6 |= IPV6_SPECIAL_V4MAPPING;
  49     } else {
  50         debugs(3, 2, "Detected split IPv4 and IPv6 stacks ...");
  51         EnableIpv6 |= IPV6_SPECIAL_SPLITSTACK;
  52     }
  53 #else
  54     // compliance here means they at least supply the option for compilers building code
  55     // even if possibly to return hard-coded -1 on use.
  56     debugs(3, 2, "Missing RFC 3493 compliance - attempting split IPv4 and IPv6 stacks ...");
  57     EnableIpv6 |= IPV6_SPECIAL_SPLITSTACK;
  58 #endif
  59
  60     // Test for IPv6 loopback/localhost address binding
  61     Ip::Address ip;
  62     ip.setLocalhost();
  63     if (ip.isIPv6()) { // paranoid; always succeeds if we got this far
  64         struct sockaddr_in6 sin;
  65         ip.getSockAddr(sin);
  66         if (bind(s, reinterpret_cast<struct sockaddr *>(&sin), sizeof(sin)) != 0) {
  67             debugs(3, DBG_CRITICAL, "WARNING: BCP 177 violation. Detected non-functional IPv6 loopback.");
  68             EnableIpv6 = IPV6_OFF;
  69         } else {
  70             debugs(3, 2, "Detected functional IPv6 loopback ...");
  71         }
  72     }
  73
  74     close(s);
  75
  76 #if USE_IPV6
  77     debugs(3, 2, "IPv6 transport " << (EnableIpv6?"Enabled":"Disabled"));
  78 #else
  79     debugs(3, 2, "IPv6 transport " << (EnableIpv6?"Available":"Disabled"));
  80     if (EnableIpv6 != IPV6_OFF) {
  81         debugs(3, DBG_CRITICAL, "WARNING: BCP 177 violation. IPv6 transport forced OFF by build parameters.");
  82         EnableIpv6 = IPV6_OFF;
  83     }
  84 #endif
  85 }
  86