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// Parsed results of a Hosts file.
48//
49// Although Hosts files map IP address to a list of domain names, for name
50// resolution the desired mapping direction is: domain name to IP address.
51// When parsing Hosts, we apply the "first hit" rule as Windows and glibc do.
52// With a Hosts file of:
53// 300.300.300.300 localhost # bad ip
54// 127.0.0.1 localhost
55// 10.0.0.1 localhost
56// The expected resolution of localhost is 127.0.0.1.
57#if !defined(OS_ANDROID)
58typedef base::hash_map<DnsHostsKey, IPAddressNumber> DnsHosts;
59#else
60// Android's hash_map doesn't support ==, so fall back to map.  (Chromium on
61// Android doesn't use the built-in DNS resolver anyway, so it's irrelevant.)
62typedef std::map<DnsHostsKey, IPAddressNumber> DnsHosts;
63#endif
64
65// Parses |contents| (as read from /etc/hosts or equivalent) and stores results
66// in |dns_hosts|. Invalid lines are ignored (as in most implementations).
67void NET_EXPORT_PRIVATE ParseHosts(const std::string& contents,
68                                   DnsHosts* dns_hosts);
69
70// As above but reads the file pointed to by |path|.
71bool NET_EXPORT_PRIVATE ParseHostsFile(const base::FilePath& path,
72                                       DnsHosts* dns_hosts);
73
74
75
76}  // namespace net
77
78#endif  // NET_DNS_DNS_HOSTS_H_
79
80