1 // Copyright (c) 2012 The Chromium Authors. All rights reserved. 2 // Use of this source code is governed by a BSD-style license that can be 3 // found in the LICENSE file. 4 5 #ifndef NET_DNS_DNS_HOSTS_H_ 6 #define NET_DNS_DNS_HOSTS_H_ 7 8 #include <map> 9 #include <string> 10 #include <utility> 11 #include <vector> 12 13 #include "base/basictypes.h" 14 #include "base/containers/hash_tables.h" 15 #include "base/files/file_path.h" 16 #include "net/base/address_family.h" 17 #include "net/base/net_export.h" 18 #include "net/base/net_util.h" // can't forward-declare IPAddressNumber 19 20 namespace net { 21 typedef std::pair<std::string, AddressFamily> DnsHostsKey; 22 }; 23 24 namespace BASE_HASH_NAMESPACE { 25 #if defined(COMPILER_GCC) 26 27 template<> 28 struct hash<net::DnsHostsKey> { 29 std::size_t operator()(const net::DnsHostsKey& key) const { 30 hash<base::StringPiece> string_piece_hash; 31 return string_piece_hash(key.first) + key.second; 32 } 33 }; 34 35 #elif defined(COMPILER_MSVC) 36 37 inline size_t hash_value(const net::DnsHostsKey& key) { 38 return hash_value(key.first) + key.second; 39 } 40 41 #endif // COMPILER 42 43 } // namespace BASE_HASH_NAMESPACE 44 45 namespace net { 46 47 // There are OS-specific variations in how commas in the hosts file behave. 48 enum ParseHostsCommaMode { 49 // Comma is treated as part of a hostname: 50 // "127.0.0.1 foo,bar" parses as "foo,bar" mapping to "127.0.0.1". 51 PARSE_HOSTS_COMMA_IS_TOKEN, 52 53 // Comma is treated as a hostname separator: 54 // "127.0.0.1 foo,bar" parses as "foo" and "bar" both mapping to "127.0.0.1". 55 PARSE_HOSTS_COMMA_IS_WHITESPACE, 56 }; 57 58 // Parsed results of a Hosts file. 59 // 60 // Although Hosts files map IP address to a list of domain names, for name 61 // resolution the desired mapping direction is: domain name to IP address. 62 // When parsing Hosts, we apply the "first hit" rule as Windows and glibc do. 63 // With a Hosts file of: 64 // 300.300.300.300 localhost # bad ip 65 // 127.0.0.1 localhost 66 // 10.0.0.1 localhost 67 // The expected resolution of localhost is 127.0.0.1. 68 #if !defined(OS_ANDROID) 69 typedef base::hash_map<DnsHostsKey, IPAddressNumber> DnsHosts; 70 #else 71 // Android's hash_map doesn't support ==, so fall back to map. (Chromium on 72 // Android doesn't use the built-in DNS resolver anyway, so it's irrelevant.) 73 typedef std::map<DnsHostsKey, IPAddressNumber> DnsHosts; 74 #endif 75 76 // Parses |contents| (as read from /etc/hosts or equivalent) and stores results 77 // in |dns_hosts|. Invalid lines are ignored (as in most implementations). 78 // Overrides the OS-specific default handling of commas, so unittests can test 79 // both modes. 80 void NET_EXPORT_PRIVATE ParseHostsWithCommaModeForTesting( 81 const std::string& contents, 82 DnsHosts* dns_hosts, 83 ParseHostsCommaMode comma_mode); 84 85 // Parses |contents| (as read from /etc/hosts or equivalent) and stores results 86 // in |dns_hosts|. Invalid lines are ignored (as in most implementations). 87 void NET_EXPORT_PRIVATE ParseHosts(const std::string& contents, 88 DnsHosts* dns_hosts); 89 90 // As above but reads the file pointed to by |path|. 91 bool NET_EXPORT_PRIVATE ParseHostsFile(const base::FilePath& path, 92 DnsHosts* dns_hosts); 93 94 95 96 } // namespace net 97 98 #endif // NET_DNS_DNS_HOSTS_H_ 99 100