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 20namespace net { 21 typedef std::pair<std::string, AddressFamily> DnsHostsKey; 22}; 23 24namespace BASE_HASH_NAMESPACE { 25#if defined(COMPILER_GCC) 26 27template<> 28struct 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 37inline 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 45namespace net { 46 47// There are OS-specific variations in how commas in the hosts file behave. 48enum 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) 69typedef 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.) 73typedef 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. 80void 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). 87void NET_EXPORT_PRIVATE ParseHosts(const std::string& contents, 88 DnsHosts* dns_hosts); 89 90// As above but reads the file pointed to by |path|. 91bool 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