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
ProbeTransport()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
87