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