net/base/dns_util.h

   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
  14 namespace 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"
  21 NET_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.
  26 NET_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)
  31 NET_EXPORT_PRIVATE bool IsSTD3ASCIIValidCharacter(char c);
  32
  33 // Returns the hostname by trimming the ending dot, if one exists.
  34 NET_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.
  40 static 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.
  46 static const uint16 kDNS_A = 1;
  47 static const uint16 kDNS_CNAME = 5;
  48 static const uint16 kDNS_TXT = 16;
  49 static const uint16 kDNS_AAAA = 28;
  50 static const uint16 kDNS_CERT = 37;
  51 static const uint16 kDNS_DS = 43;
  52 static const uint16 kDNS_RRSIG = 46;
  53 static const uint16 kDNS_DNSKEY = 48;
  54 static const uint16 kDNS_ANY = 0xff;
  55 static const uint16 kDNS_TESTING = 0xfffe;  // in private use area.
  56
  57 // http://www.iana.org/assignments/dns-sec-alg-numbers/dns-sec-alg-numbers.xhtml
  58 static const uint8 kDNSSEC_RSA_SHA1 = 5;
  59 static const uint8 kDNSSEC_RSA_SHA1_NSEC3 = 7;
  60 static const uint8 kDNSSEC_RSA_SHA256 = 8;
  61 static const uint8 kDNSSEC_RSA_SHA512 = 10;
  62
  63 // RFC 4509
  64 static const uint8 kDNSSEC_SHA1 = 1;
  65 static const uint8 kDNSSEC_SHA256 = 2;
  66
  67 // A Buffer is used for walking over a DNS response packet.
  68 class DnsResponseBuffer {
  69  public:
  70   DnsResponseBuffer(const uint8* p, unsigned len)
  71       : p_(p),
  72         packet_(p),
  73         len_(len),
  74         packet_len_(len) {
  75   }
  76
  77   bool U8(uint8* v);
  78   bool U16(uint16* v);
  79   bool U32(uint32* v);
  80   bool Skip(unsigned n);
  81
  82   bool Block(base::StringPiece* out, unsigned len);
  83
  84   // DNSName parses a (possibly compressed) DNS name from the packet. If |name|
  85   // is not NULL, then the name is written into it. See RFC 1035 section 4.1.4.
  86   bool DNSName(std::string* name);
  87
  88  private:
  89   const uint8* p_;
  90   const uint8* const packet_;
  91   unsigned len_;
  92   const unsigned packet_len_;
  93
  94   DISALLOW_COPY_AND_ASSIGN(DnsResponseBuffer);
  95 };
  96
  97
  98 }  // namespace net
  99
 100 #endif  // NET_BASE_DNS_UTIL_H_