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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 { | |
mmenke
2011/12/02 00:53:55
nit: Google style is to have an empty line here.
szym
2011/12/05 23:06:28
Done.
| |
14 namespace dns_protocol { | |
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 | |
mmenke
2011/12/02 00:53:55
nit: Missing period.
szym
2011/12/05 23:06:28
Done.
| |
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 00:53:55
nit: add a blank line.
szym
2011/12/05 23:06:28
Done.
| |
118 } // namespace net | |
119 | |
120 #endif // NET_DNS_DNS_PROTOCOL_H_ | |
121 | |
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