| // Copyright (c) 2012 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_DNS_DNS_HOSTS_H_ |
| #define NET_DNS_DNS_HOSTS_H_ |
| |
| #include <stddef.h> |
| |
| #include <map> |
| #include <string> |
| #include <unordered_map> |
| #include <utility> |
| #include <vector> |
| |
| #include "base/files/file_path.h" |
| #include "base/strings/string_piece.h" |
| #include "net/base/address_family.h" |
| #include "net/base/ip_address.h" |
| #include "net/base/net_export.h" |
| |
| namespace net { |
| |
| using DnsHostsKey = std::pair<std::string, AddressFamily>; |
| |
| struct DnsHostsKeyHash { |
| std::size_t operator()(const DnsHostsKey& key) const { |
| return base::StringPieceHash()(key.first) + key.second; |
| } |
| }; |
| |
| // There are OS-specific variations in how commas in the hosts file behave. |
| enum ParseHostsCommaMode { |
| // Comma is treated as part of a hostname: |
| // "127.0.0.1 foo,bar" parses as "foo,bar" mapping to "127.0.0.1". |
| PARSE_HOSTS_COMMA_IS_TOKEN, |
| |
| // Comma is treated as a hostname separator: |
| // "127.0.0.1 foo,bar" parses as "foo" and "bar" both mapping to "127.0.0.1". |
| PARSE_HOSTS_COMMA_IS_WHITESPACE, |
| }; |
| |
| // Parsed results of a Hosts file. |
| // |
| // Although Hosts files map IP address to a list of domain names, for name |
| // resolution the desired mapping direction is: domain name to IP address. |
| // When parsing Hosts, we apply the "first hit" rule as Windows and glibc do. |
| // With a Hosts file of: |
| // 300.300.300.300 localhost # bad ip |
| // 127.0.0.1 localhost |
| // 10.0.0.1 localhost |
| // The expected resolution of localhost is 127.0.0.1. |
| using DnsHosts = std::unordered_map<DnsHostsKey, IPAddress, DnsHostsKeyHash>; |
| |
| // Parses |contents| (as read from /etc/hosts or equivalent) and stores results |
| // in |dns_hosts|. Invalid lines are ignored (as in most implementations). |
| // Overrides the OS-specific default handling of commas, so unittests can test |
| // both modes. |
| void NET_EXPORT_PRIVATE ParseHostsWithCommaModeForTesting( |
| const std::string& contents, |
| DnsHosts* dns_hosts, |
| ParseHostsCommaMode comma_mode); |
| |
| // Parses |contents| (as read from /etc/hosts or equivalent) and stores results |
| // in |dns_hosts|. Invalid lines are ignored (as in most implementations). |
| void NET_EXPORT_PRIVATE ParseHosts(const std::string& contents, |
| DnsHosts* dns_hosts); |
| |
| // Test-injectable HOSTS parser. |
| class NET_EXPORT_PRIVATE DnsHostsParser { |
| public: |
| virtual ~DnsHostsParser(); |
| |
| // Parses HOSTS and stores results in `dns_hosts`, with addresses in the order |
| // in which they were read. Invalid lines are ignored (as in most |
| // implementations). |
| virtual bool ParseHosts(DnsHosts* hosts) const = 0; |
| }; |
| |
| // Implementation of `DnsHostsParser` that reads HOSTS from a given file. |
| class NET_EXPORT_PRIVATE DnsHostsFileParser : public DnsHostsParser { |
| public: |
| explicit DnsHostsFileParser(base::FilePath hosts_file_path); |
| ~DnsHostsFileParser() override; |
| |
| DnsHostsFileParser(const DnsHostsFileParser&) = delete; |
| DnsHostsFileParser& operator=(const DnsHostsFileParser&) = delete; |
| |
| // DnsHostsParser: |
| bool ParseHosts(DnsHosts* dns_hosts) const override; |
| |
| private: |
| const base::FilePath hosts_file_path_; |
| }; |
| |
| } // namespace net |
| |
| #endif // NET_DNS_DNS_HOSTS_H_ |