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| 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 #include "net/base/dns_query.h" | |
| 6 | |
| 7 #include <string> | |
| 8 | |
| 9 #include "base/rand_util.h" | |
| 10 #include "net/base/address_family.h" | |
| 11 #include "net/base/dns_util.h" | |
| 12 | |
| 13 namespace net { | |
| 14 | |
| 15 namespace { | |
| 16 | |
| 17 void PackUint16BE(char buf[2], uint16 v) { | |
| 18 buf[0] = v >> 8; | |
| 19 buf[1] = v & 0xff; | |
| 20 } | |
| 21 | |
| 22 uint16 QTypeFromAddressFamily(AddressFamily address_family) { | |
| 23 switch (address_family) { | |
| 24 case ADDRESS_FAMILY_IPV4: | |
| 25 return kDNS_A; | |
| 26 case ADDRESS_FAMILY_IPV6: | |
| 27 return kDNS_AAAA; | |
| 28 default: | |
| 29 NOTREACHED() << "Bad address family"; | |
| 30 return kDNS_A; | |
| 31 } | |
| 32 } | |
| 33 | |
| 34 } // namespace | |
| 35 | |
| 36 // DNS query consists of a 12-byte header followed by a question section. | |
| 37 // For details, see RFC 1035 section 4.1.1. This header template sets RD | |
| 38 // bit, which directs the name server to pursue query recursively, and sets | |
| 39 // the QDCOUNT to 1, meaning the question section has a single entry. The | |
| 40 // first two bytes of the header form a 16-bit random query ID to be copied | |
| 41 // in the corresponding reply by the name server -- randomized during | |
| 42 // DnsQuery construction. | |
| 43 static const char kHeader[] = {0x00, 0x00, 0x01, 0x00, 0x00, 0x01, | |
| 44 0x00, 0x00, 0x00, 0x00, 0x00, 0x00}; | |
| 45 static const size_t kHeaderLen = arraysize(kHeader); | |
| 46 | |
| 47 DnsQuery::DnsQuery(const std::string& hostname, | |
| 48 AddressFamily address_family, | |
| 49 int port) | |
| 50 : port_(port), | |
| 51 id_(0), | |
| 52 qtype_(QTypeFromAddressFamily(address_family)), | |
| 53 hostname_(hostname) { | |
| 54 std::string qname; | |
| 55 if (!net::DNSDomainFromDot(hostname, &qname)) | |
| 56 return; | |
| 57 | |
| 58 size_t query_size = kHeaderLen + qname.size() + | |
| 59 sizeof(qtype_) + sizeof(kClassIN); | |
| 60 | |
| 61 io_buffer_ = new IOBufferWithSize(query_size); | |
| 62 | |
| 63 int byte_offset = 0; | |
| 64 char* buffer_head = io_buffer_->data(); | |
| 65 memcpy(&buffer_head[byte_offset], kHeader, kHeaderLen); | |
| 66 byte_offset += kHeaderLen; | |
| 67 memcpy(&buffer_head[byte_offset], &qname[0], qname.size()); | |
| 68 byte_offset += qname.size(); | |
| 69 PackUint16BE(&buffer_head[byte_offset], qtype_); | |
| 70 byte_offset += sizeof(qtype_); | |
| 71 PackUint16BE(&buffer_head[byte_offset], kClassIN); | |
| 72 | |
| 73 // Randomize ID, first two bytes. | |
| 74 id_ = base::RandUint64() & 0xffff; | |
| 75 PackUint16BE(&buffer_head[0], id_); | |
| 76 } | |
| 77 | |
| 78 int DnsQuery::port() const { | |
| 79 DCHECK(IsValid()); | |
| 80 return port_; | |
| 81 } | |
| 82 | |
| 83 uint16 DnsQuery::id() const { | |
| 84 DCHECK(IsValid()); | |
| 85 return id_; | |
| 86 } | |
| 87 | |
| 88 uint16 DnsQuery::qtype() const { | |
| 89 DCHECK(IsValid()); | |
| 90 return qtype_; | |
| 91 } | |
| 92 | |
| 93 AddressFamily DnsQuery::address_family() const { | |
| 94 DCHECK(IsValid()); | |
| 95 return address_family_; | |
| 96 } | |
| 97 | |
| 98 const std::string& DnsQuery::hostname() const { | |
| 99 DCHECK(IsValid()); | |
| 100 return hostname_; | |
| 101 } | |
| 102 | |
| 103 IOBufferWithSize* DnsQuery::io_buffer() const { | |
| 104 DCHECK(IsValid()); | |
| 105 return io_buffer_.get(); | |
| 106 } | |
| 107 | |
| 108 } // namespace net | |
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Chromium Code Reviews
Issue 7056050:
Revert 87809 - Added DnsQuery class (Closed)
Base URL: svn://svn.chromium.org/chrome/trunk/src/