net/dns/mapped_ip_resolver.h

   1 // Copyright 2014 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_IP_RESOLVER_H_
   6 #define NET_DNS_MAPPED_IP_RESOLVER_H_
   7
   8 #include <string>
   9
  10 #include "base/memory/scoped_ptr.h"
  11 #include "base/memory/weak_ptr.h"
  12 #include "net/base/ip_mapping_rules.h"
  13 #include "net/base/net_export.h"
  14 #include "net/dns/host_resolver.h"
  15
  16 namespace net {
  17
  18 // This class wraps an existing HostResolver instance, but modifies the
  19 // resolution response by inserting or replacing IP addresses before returning
  20 // it.  Currently, the only directive suported is a "PREFACE" directive which
  21 // (when a match exists) inserts a single IP address at the start of a list.
  22 class NET_EXPORT MappedIPResolver : public HostResolver {
  23  public:
  24   // Creates a MappedIPResolver that forwards all of its requests through
  25   // |impl|.
  26   explicit MappedIPResolver(scoped_ptr<HostResolver> impl);
  27   virtual ~MappedIPResolver();
  28
  29   // Adds a rule to our IP mapper rules_.
  30   // The most recently added rule "has priority" and will be used first (in
  31   // preference to) any previous rules.  Once one rule is found that matches,
  32   // no other rules will be considered.
  33   // See ip_mapping_rules.h for syntax and semantics.
  34   // Returns true if the rule was successfully parsed and added.
  35   bool AddRuleFromString(const std::string& rule_string) {
  36     return rules_.AddRuleFromString(rule_string);
  37   }
  38
  39   // Takes a semicolon separated list of rules, and assigns them to this
  40   // resolver, discarding any previously added or set rules.
  41   void SetRulesFromString(const std::string& rules_string) {
  42     rules_.SetRulesFromString(rules_string);
  43   }
  44
  45   // HostResolver methods:
  46   virtual int Resolve(const RequestInfo& info,
  47                       RequestPriority priority,
  48                       AddressList* addresses,
  49                       const CompletionCallback& callback,
  50                       RequestHandle* out_req,
  51                       const BoundNetLog& net_log) OVERRIDE;
  52   virtual int ResolveFromCache(const RequestInfo& info,
  53                                AddressList* addresses,
  54                                const BoundNetLog& net_log) OVERRIDE;
  55   virtual void CancelRequest(RequestHandle req) OVERRIDE;
  56   virtual void SetDnsClientEnabled(bool enabled) OVERRIDE;
  57   virtual HostCache* GetHostCache() OVERRIDE;
  58   virtual base::Value* GetDnsConfigAsValue() const OVERRIDE;
  59
  60  private:
  61   // Modify the list of resolution |addresses| according to |rules_|, and then
  62   // calls the |original_callback| with network error code |rv|.
  63   void ApplyRules(const CompletionCallback& original_callback,
  64                   AddressList* addresses,
  65                   int rv) const;
  66
  67   scoped_ptr<HostResolver> impl_;
  68   IPMappingRules rules_;
  69
  70   base::WeakPtrFactory<MappedIPResolver> weak_factory_;
  71   DISALLOW_COPY_AND_ASSIGN(MappedIPResolver);
  72 };
  73
  74 }  // namespace net
  75
  76 #endif  // NET_DNS_MAPPED_IP_RESOLVER_H_