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Side by Side Diff: net/dns/dns_protocol.h

Issue 8762001: Isolates generic DnsClient from AsyncHostResolver. (Closed) Base URL: svn://svn.chromium.org/chrome/trunk/src
Patch Set: fix out-of-bounds access; more sensible error codes Created 9 years ago
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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 #ifndef NET_DNS_DNS_PROTOCOL_H_
6 #define NET_DNS_DNS_PROTOCOL_H_
7 #pragma once
8
9 #include "base/basictypes.h"
10 #include "net/base/bigendian.h"
11 #include "net/base/net_export.h"
12
13 namespace net {
14 namespace dns_protocol {
mmenke 2011/12/02 00:53:56 nit: Should be a blank line before the inner name
szym 2011/12/05 23:06:28 Done.
15
16 // DNS packet consists of a header followed by questions and/or answers.
17 // For the meaning of specific fields, please see RFC 1035 and 2535
18
19 // Header format.
20 // 1 1 1 1 1 1
21 // 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5
22 // +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
23 // | ID |
24 // +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
25 // |QR| Opcode |AA|TC|RD|RA| Z|AD|CD| RCODE |
26 // +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
27 // | QDCOUNT |
28 // +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
29 // | ANCOUNT |
30 // +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
31 // | NSCOUNT |
32 // +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
33 // | ARCOUNT |
34 // +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
35
36 // Question format.
37 // 1 1 1 1 1 1
38 // 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5
39 // +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
40 // | |
41 // / QNAME /
42 // / /
43 // +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
44 // | QTYPE |
45 // +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
46 // | QCLASS |
47 // +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
48
49 // Answer format.
50 // 1 1 1 1 1 1
51 // 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5
52 // +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
53 // | |
54 // / /
55 // / NAME /
56 // | |
57 // +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
58 // | TYPE |
59 // +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
60 // | CLASS |
61 // +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
62 // | TTL |
63 // | |
64 // +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
65 // | RDLENGTH |
66 // +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--|
67 // / RDATA /
68 // / /
69 // +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
70
71 #pragma pack(push)
72 #pragma pack(1)
73
74 // On-the-wire header. All uint16 are in network order.
75 // Used internally in DnsQuery and DnsResponseParser
76 struct NET_EXPORT_PRIVATE Header {
77 uint16 id;
78 uint8 flags[2];
79 uint16 qdcount;
80 uint16 ancount;
81 uint16 nscount;
82 uint16 arcount;
83 };
84
85 #pragma pack(pop)
86
87 static const uint8 kLabelMask = 0xc0;
88 static const uint8 kLabelPointer = 0xc0;
89 static const uint8 kLabelDirect = 0x0;
90 static const uint16 kOffsetMask = 0x3fff;
91
92 static const int kMaxNameLength = 255;
93
94 // RFC 1035, section 4.2.1: Messages carried by UDP are restricted to 512
95 // bytes (not counting the IP nor UDP headers).
96 static const int kMaxUDPSize = 512;
97
98 // DNS class types.
99 static const uint16 kClassIN = 1;
100
101 // DNS resource record types. See
102 // http://www.iana.org/assignments/dns-parameters
103 static const uint16 kTypeA = 1;
104 static const uint16 kTypeCNAME = 5;
105 static const uint16 kTypeTXT = 16;
106 static const uint16 kTypeAAAA = 28;
107
108 // DNS rcode values.
109 static const uint8 kRcodeMask = 0xf;
110 static const uint8 kRcodeNOERROR = 0;
111 static const uint8 kRcodeFORMERR = 1;
112 static const uint8 kRcodeSERVFAIL = 2;
113 static const uint8 kRcodeNXDOMAIN = 3;
114 static const uint8 kRcodeNOTIMP = 4;
115 static const uint8 kRcodeREFUSED = 5;
116
117 } // namespace dns_protocol
mmenke 2011/12/02 00:53:56 nit: Blank line needed.
szym 2011/12/05 23:06:28 Done.
118 } // namespace net
119
120 #endif // NET_DNS_DNS_PROTOCOL_H_
121
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