[Linux] Enable connecting to localhost when offline.

net/base/net_util.cc

 // Copyright (c) 2010 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "net/base/net_util.h"
 
 #include <algorithm>
 #include <map>
 #include <unicode/ucnv.h>
 #include <unicode/uidna.h>
@@ skipping 1765 matching lines @@
   }
 
   IPv6SupportResults(IPV6_GLOBAL_ADDRESS_MISSING);
   return false;
 #else
   NOTIMPLEMENTED();
   return true;
 #endif  // defined(various platforms)
 }
 
+bool HaveOnlyLoopbackAddresses() {
+#if defined(OS_POSIX)
+  struct ifaddrs* interface_addr = NULL;
+  int rv = getifaddrs(&interface_addr);
+  if (rv != 0) {
+    DLOG(INFO) << "getifaddrs() failed with errno = " << errno;
+    return false;
+  }
+
+  bool result = true;
+  for (struct ifaddrs* interface = interface_addr;
+       interface != NULL;
+       interface = interface->ifa_next) {
+    if (!(IFF_UP & interface->ifa_flags))
+      continue;
+    if (IFF_LOOPBACK & interface->ifa_flags)
+      continue;
+    const struct sockaddr* addr = interface->ifa_addr;
+    if (!addr)
+      continue;
+    if (addr->sa_family != AF_INET6 && addr->sa_family != AF_INET)
+      continue;
+
+    result = false;
+    break;
+  }
+  freeifaddrs(interface_addr);
+  return result;
+#else
+  NOTIMPLEMENTED();
+  return false;
+#endif  // defined(various platforms)
+}
+
 bool ParseIPLiteralToNumber(const std::string& ip_literal,
                             IPAddressNumber* ip_number) {
   // |ip_literal| could be either a IPv4 or an IPv6 literal. If it contains
   // a colon however, it must be an IPv6 address.
   if (ip_literal.find(':') != std::string::npos) {
     // GURL expects IPv6 hostnames to be surrounded with brackets.
     std::string host_brackets = "[" + ip_literal + "]";
     url_parse::Component host_comp(0, host_brackets.size());
 
     // Try parsing the hostname as an IPv6 literal.
@@ skipping 120 matching lines @@
 }
 
 int GetPortFromAddrinfo(const struct addrinfo* info) {
   uint16* port_field = GetPortFieldFromAddrinfo(info);
   if (!port_field)
     return -1;
   return ntohs(*port_field);
 }
 
 }  // namespace net