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_MAPPED_HOST_RESOLVER_H_
6#define NET_DNS_MAPPED_HOST_RESOLVER_H_
7
8#include <string>
9
10#include "base/memory/scoped_ptr.h"
11#include "net/base/host_mapping_rules.h"
12#include "net/base/net_export.h"
13#include "net/dns/host_resolver.h"
14
15namespace net {
16
17// This class wraps an existing HostResolver instance, but modifies the
18// request before passing it off to |impl|. This is different from
19// MockHostResolver which does the remapping at the HostResolverProc
20// layer, so it is able to preserve the effectiveness of the cache.
21class NET_EXPORT MappedHostResolver : public HostResolver {
22 public:
23  // Creates a MappedHostResolver that forwards all of its requests through
24  // |impl|.
25  explicit MappedHostResolver(scoped_ptr<HostResolver> impl);
26  virtual ~MappedHostResolver();
27
28  // Adds a rule to this mapper. The format of the rule can be one of:
29  //
30  //   "MAP" <hostname_pattern> <replacement_host> [":" <replacement_port>]
31  //   "EXCLUDE" <hostname_pattern>
32  //
33  // The <replacement_host> can be either a hostname, or an IP address literal,
34  // or "~NOTFOUND". If it is "~NOTFOUND" then all matched hostnames will fail
35  // to be resolved with ERR_NAME_NOT_RESOLVED.
36  //
37  // Returns true if the rule was successfully parsed and added.
38  bool AddRuleFromString(const std::string& rule_string) {
39    return rules_.AddRuleFromString(rule_string);
40  }
41
42  // Takes a comma separated list of rules, and assigns them to this resolver.
43  void SetRulesFromString(const std::string& rules_string) {
44    rules_.SetRulesFromString(rules_string);
45  }
46
47  // HostResolver methods:
48  virtual int Resolve(const RequestInfo& info,
49                      RequestPriority priority,
50                      AddressList* addresses,
51                      const CompletionCallback& callback,
52                      RequestHandle* out_req,
53                      const BoundNetLog& net_log) OVERRIDE;
54  virtual int ResolveFromCache(const RequestInfo& info,
55                               AddressList* addresses,
56                               const BoundNetLog& net_log) OVERRIDE;
57  virtual void CancelRequest(RequestHandle req) OVERRIDE;
58  virtual void SetDnsClientEnabled(bool enabled) OVERRIDE;
59  virtual HostCache* GetHostCache() OVERRIDE;
60  virtual base::Value* GetDnsConfigAsValue() const OVERRIDE;
61
62 private:
63  // Modify the request |info| according to |rules_|. Returns either OK or
64  // the network error code that the hostname's resolution mapped to.
65  int ApplyRules(RequestInfo* info) const;
66
67  scoped_ptr<HostResolver> impl_;
68
69  HostMappingRules rules_;
70};
71
72}  // namespace net
73
74#endif  // NET_DNS_MAPPED_HOST_RESOLVER_H_
75