net/dns/dns_query.h

   1 // Copyright (c) 2011 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_QUERY_H_
   6 #define NET_DNS_DNS_QUERY_H_
   7
   8 #include "base/basictypes.h"
   9 #include "base/memory/ref_counted.h"
  10 #include "base/strings/string_piece.h"
  11 #include "net/base/net_export.h"
  12
  13 namespace net {
  14
  15 class IOBufferWithSize;
  16
  17 // Represents on-the-wire DNS query message as an object.
  18 // TODO(szym): add support for the OPT pseudo-RR (EDNS0/DNSSEC).
  19 class NET_EXPORT_PRIVATE DnsQuery {
  20  public:
  21   // Constructs a query message from |qname| which *MUST* be in a valid
  22   // DNS name format, and |qtype|. The qclass is set to IN.
  23   DnsQuery(uint16 id, const base::StringPiece& qname, uint16 qtype);
  24   ~DnsQuery();
  25
  26   // Clones |this| verbatim, with ID field of the header set to |id|.
  27   DnsQuery* CloneWithNewId(uint16 id) const;
  28
  29   // DnsQuery field accessors.
  30   uint16 id() const;
  31   base::StringPiece qname() const;
  32   uint16 qtype() const;
  33
  34   // Returns the Question section of the query.  Used when matching the
  35   // response.
  36   base::StringPiece question() const;
  37
  38   // IOBuffer accessor to be used for writing out the query.
  39   IOBufferWithSize* io_buffer() const { return io_buffer_.get(); }
  40
  41   void set_flags(uint16 flags);
  42
  43  private:
  44   DnsQuery(const DnsQuery& orig, uint16 id);
  45
  46   // Size of the DNS name (*NOT* hostname) we are trying to resolve; used
  47   // to calculate offsets.
  48   size_t qname_size_;
  49
  50   // Contains query bytes to be consumed by higher level Write() call.
  51   scoped_refptr<IOBufferWithSize> io_buffer_;
  52
  53   DISALLOW_COPY_AND_ASSIGN(DnsQuery);
  54 };
  55
  56 }  // namespace net
  57
  58 #endif  // NET_DNS_DNS_QUERY_H_