dns_util.h revision 5821806d5e7f356e8fa4b058a389a808ea183019 
1// Copyright (c) 2012 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_BASE_DNS_UTIL_H_
6#define NET_BASE_DNS_UTIL_H_
7
8#include <string>
9
10#include "base/basictypes.h"
11#include "base/string_piece.h"
12#include "net/base/net_export.h"
13
14namespace net {
15
16// DNSDomainFromDot - convert a domain string to DNS format. From DJB's
17// public domain DNS library.
18//
19//   dotted: a string in dotted form: "www.google.com"
20//   out: a result in DNS form: "\x03www\x06google\x03com\x00"
21NET_EXPORT_PRIVATE bool DNSDomainFromDot(const base::StringPiece& dotted,
22                                         std::string* out);
23
24// DNSDomainToString converts a domain in DNS format to a dotted string.
25// Excludes the dot at the end.
26NET_EXPORT_PRIVATE std::string DNSDomainToString(
27    const base::StringPiece& domain);
28
29// Returns true iff the given character is in the set of valid DNS label
30// characters as given in RFC 3490, 4.1, 3(a)
31NET_EXPORT_PRIVATE bool IsSTD3ASCIIValidCharacter(char c);
32
33// Returns the hostname by trimming the ending dot, if one exists.
34NET_EXPORT std::string TrimEndingDot(const base::StringPiece& host);
35
36// TODO(szym): remove all definitions below once DnsRRResolver migrates to
37// DnsClient
38
39// DNS class types.
40static const uint16 kClassIN = 1;
41
42// DNS resource record types. See
43// http://www.iana.org/assignments/dns-parameters
44// WARNING: if you're adding any new values here you may need to add them to
45// dnsrr_resolver.cc:DnsRRIsParsedByWindows.
46static const uint16 kDNS_A = 1;
47static const uint16 kDNS_CNAME = 5;
48static const uint16 kDNS_TXT = 16;
49static const uint16 kDNS_AAAA = 28;
50static const uint16 kDNS_CERT = 37;
51static const uint16 kDNS_DS = 43;
52static const uint16 kDNS_RRSIG = 46;
53static const uint16 kDNS_DNSKEY = 48;
54static const uint16 kDNS_ANY = 0xff;
55static const uint16 kDNS_CAA = 257;
56static const uint16 kDNS_TESTING = 0xfffe;  // in private use area.
57
58// http://www.iana.org/assignments/dns-sec-alg-numbers/dns-sec-alg-numbers.xhtml
59static const uint8 kDNSSEC_RSA_SHA1 = 5;
60static const uint8 kDNSSEC_RSA_SHA1_NSEC3 = 7;
61static const uint8 kDNSSEC_RSA_SHA256 = 8;
62static const uint8 kDNSSEC_RSA_SHA512 = 10;
63
64// RFC 4509
65static const uint8 kDNSSEC_SHA1 = 1;
66static const uint8 kDNSSEC_SHA256 = 2;
67
68// A Buffer is used for walking over a DNS response packet.
69class DnsResponseBuffer {
70 public:
71  DnsResponseBuffer(const uint8* p, unsigned len)
72      : p_(p),
73        packet_(p),
74        len_(len),
75        packet_len_(len) {
76  }
77
78  bool U8(uint8* v);
79  bool U16(uint16* v);
80  bool U32(uint32* v);
81  bool Skip(unsigned n);
82
83  bool Block(base::StringPiece* out, unsigned len);
84
85  // DNSName parses a (possibly compressed) DNS name from the packet. If |name|
86  // is not NULL, then the name is written into it. See RFC 1035 section 4.1.4.
87  bool DNSName(std::string* name);
88
89 private:
90  const uint8* p_;
91  const uint8* const packet_;
92  unsigned len_;
93  const unsigned packet_len_;
94
95  DISALLOW_COPY_AND_ASSIGN(DnsResponseBuffer);
96};
97
98
99}  // namespace net
100
101#endif  // NET_BASE_DNS_UTIL_H_
102