[Linux] Enable connecting to localhost when offline.

net/base/net_util.h

 // 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.
 
 #ifndef NET_BASE_NET_UTIL_H_
 #define NET_BASE_NET_UTIL_H_
 
 #include "build/build_config.h"
 
 #ifdef OS_WIN
@@ skipping 309 matching lines @@
 //   - reference section
 GURL SimplifyUrlForRequest(const GURL& url);
 
 void SetExplicitlyAllowedPorts(const std::wstring& allowed_ports);
 
 // Perform a simplistic test to see if IPv6 is supported by trying to create an
 // IPv6 socket.
 // TODO(jar): Make test more in-depth as needed.
 bool IPv6Supported();
 
+// Returns true if it can determine that only loopback addresses are configured.
+// i.e. if only 127.0.0.1 and ::1 are routable.
+bool HaveOnlyLoopbackAddresses();
+
 // IPAddressNumber is used to represent an IP address's numeric value as an
 // array of bytes, from most significant to least significant. This is the
 // network byte ordering.
 //
 // IPv4 addresses will have length 4, whereas IPv6 address will have length 16.
 typedef std::vector<unsigned char> IPAddressNumber;
 
 // Parses an IP address literal (either IPv4 or IPv6) to its numeric value.
 // Returns true on success and fills |ip_number| with the numeric value.
 bool ParseIPLiteralToNumber(const std::string& ip_literal,
@@ skipping 34 matching lines @@
 
 // Returns the port field of the sockaddr in |info|.
 uint16* GetPortFieldFromAddrinfo(const struct addrinfo* info);
 
 // Returns the value of |info's| port (in host byte ordering).
 int GetPortFromAddrinfo(const struct addrinfo* info);
 
 }  // namespace net
 
 #endif  // NET_BASE_NET_UTIL_H_