File: dnsparser.hh

package info (click to toggle)
pdns-recursor 3.2-4+deb6u1
  • links: PTS
  • area: main
  • in suites: squeeze-lts
  • size: 1,220 kB
  • ctags: 2,721
  • sloc: cpp: 12,564; ansic: 2,587; sh: 510; makefile: 133
file content (316 lines) | stat: -rw-r--r-- 8,023 bytes parent folder | download | duplicates (2)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
/*
    PowerDNS Versatile Database Driven Nameserver
    Copyright (C) 2005  PowerDNS.COM BV

    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License version 2 as 
    published by the Free Software Foundation

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with this program; if not, write to the Free Software
    Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
*/

#ifndef DNSPARSER_HH
#define DNSPARSER_HH

#include <map>
#include <sstream>
#include <stdexcept>
#include <iostream>
#include <vector>
#include <errno.h>
// #include <netinet/in.h>
#include "misc.hh"
#include <boost/shared_ptr.hpp>
#include <boost/lexical_cast.hpp>
#include <boost/tuple/tuple.hpp>
#include <boost/tuple/tuple_comparison.hpp>
#include "dns.hh"
#include "dnswriter.hh"

/** DNS records have three representations:
    1) in the packet
    2) parsed in a class, ready for use
    3) in the zone

    We should implement bidirectional transitions between 1&2 and 2&3.
    Currently we have: 1 -> 2
                       2 -> 3

    We can add:        2 -> 1  easily by reversing the packetwriter
    And we might be able to reverse 2 -> 3 as well
*/
    
using namespace std;
#include "namespaces.hh"

class MOADNSException : public runtime_error
{
public:
  MOADNSException(const string& str) : runtime_error(str)
  {}
};


class MOADNSParser;

class PacketReader
{
public:
  PacketReader(const vector<uint8_t>& content) 
    : d_pos(0), d_content(content)
  {}

  uint32_t get32BitInt();
  uint16_t get16BitInt();
  uint8_t get8BitInt();
  
  void xfr48BitInt(uint64_t& val);

  void xfr32BitInt(uint32_t& val)
  {
    val=get32BitInt();
  }

  void xfrIP(uint32_t& val)
  {
    xfr32BitInt(val);
    val=htonl(val);
  }

  void xfrTime(uint32_t& val)
  {
    xfr32BitInt(val);
  }


  void xfr16BitInt(uint16_t& val)
  {
    val=get16BitInt();
  }

  void xfrType(uint16_t& val)
  {
    xfr16BitInt(val);
  }


  void xfr8BitInt(uint8_t& val)
  {
    val=get8BitInt();
  }


  void xfrLabel(string &label, bool compress=false)
  {
    label=getLabel();
  }

  void xfrText(string &text, bool multi=false)
  {
    text=getText(multi);
  }

  void xfrBlob(string& blob);
  void xfrBlob(string& blob, int length);
  void xfrHexBlob(string& blob);

  static uint16_t get16BitInt(const vector<unsigned char>&content, uint16_t& pos);
  static void getLabelFromContent(const vector<uint8_t>& content, uint16_t& frompos, string& ret, int recurs);

  void getDnsrecordheader(struct dnsrecordheader &ah);
  void copyRecord(vector<unsigned char>& dest, uint16_t len);
  void copyRecord(unsigned char* dest, uint16_t len);

  string getLabel(unsigned int recurs=0);
  string getText(bool multi);

  uint16_t d_pos;

private:
  uint16_t d_startrecordpos; // needed for getBlob later on
  uint16_t d_recordlen;      // dito
  const vector<uint8_t>& d_content;
};

struct DNSRecord;

class DNSRecordContent
{
public:
  static DNSRecordContent* mastermake(const DNSRecord &dr, PacketReader& pr);
  static DNSRecordContent* mastermake(uint16_t qtype, uint16_t qclass, const string& zone);

  virtual std::string getZoneRepresentation() const = 0;
  virtual ~DNSRecordContent() {}
  virtual void toPacket(DNSPacketWriter& pw)=0;
  virtual string serialize(const string& qname) // it would rock if this were const, but it is too hard
  {
    vector<uint8_t> packet;
    string empty;
    DNSPacketWriter pw(packet, empty, 1);
    
    pw.startRecord(qname, d_qtype);
    this->toPacket(pw);
    pw.commit();
    
    string record;
    pw.getRecords(record);
    return record;
  }

  static shared_ptr<DNSRecordContent> unserialize(const string& qname, uint16_t qtype, const string& serialized);

  void doRecordCheck(const struct DNSRecord&){}

  std::string label;
  struct dnsrecordheader header;

  typedef DNSRecordContent* makerfunc_t(const struct DNSRecord& dr, PacketReader& pr);  
  typedef DNSRecordContent* zmakerfunc_t(const string& str);  

  static void regist(uint16_t cl, uint16_t ty, makerfunc_t* f, zmakerfunc_t* z, const char* name)
  {
    if(f)
      getTypemap()[make_pair(cl,ty)]=f;
    if(z)
      getZmakermap()[make_pair(cl,ty)]=z;

    getNamemap()[make_pair(cl,ty)]=name;
  }

  static void unregist(uint16_t cl, uint16_t ty) 
  {
    pair<uint16_t, uint16_t> key=make_pair(cl, ty);
    getTypemap().erase(key);
    getZmakermap().erase(key);
  }

  static uint16_t TypeToNumber(const string& name)
  {
    for(namemap_t::const_iterator i=getNamemap().begin(); i!=getNamemap().end();++i)
      if(pdns_iequals(i->second, name))
        return i->first.second;

    throw runtime_error("Unknown DNS type '"+name+"'");
  }

  static const string NumberToType(uint16_t num, uint16_t classnum=1)
  {
    if(!getNamemap().count(make_pair(classnum,num)))
      return "#" + lexical_cast<string>(num);
      //      throw runtime_error("Unknown DNS type with numerical id "+lexical_cast<string>(num));
    return getNamemap()[make_pair(classnum,num)];
  }

  explicit DNSRecordContent(uint16_t type) : d_qtype(type)
  {}
  const uint16_t d_qtype;

protected:
  typedef std::map<std::pair<uint16_t, uint16_t>, makerfunc_t* > typemap_t;
  typedef std::map<std::pair<uint16_t, uint16_t>, zmakerfunc_t* > zmakermap_t;
  typedef std::map<std::pair<uint16_t, uint16_t>, string > namemap_t;

  static typemap_t& getTypemap();
  static namemap_t& getNamemap();
  static zmakermap_t& getZmakermap();
};

struct DNSRecord
{
  std::string d_label;
  uint16_t d_type;
  uint16_t d_class;
  uint32_t d_ttl;
  uint16_t d_clen;
  enum {Answer=1, Nameserver, Additional} d_place;
  boost::shared_ptr<DNSRecordContent> d_content;

  bool operator<(const DNSRecord& rhs) const
  {
    string lzrp, rzrp;
    if(d_content)
      lzrp=toLower(d_content->getZoneRepresentation());
    if(rhs.d_content)
      rzrp=toLower(rhs.d_content->getZoneRepresentation());
    
    string llabel=toLower(d_label);
    string rlabel=toLower(rhs.d_label);

    return 
      tie(llabel,     d_type,     d_class, lzrp) <
      tie(rlabel, rhs.d_type, rhs.d_class, rzrp);
  }

  bool operator==(const DNSRecord& rhs) const
  {
    string lzrp, rzrp;
    if(d_content)
      lzrp=toLower(d_content->getZoneRepresentation());
    if(rhs.d_content)
      rzrp=toLower(rhs.d_content->getZoneRepresentation());
    
    string llabel=toLower(d_label);
    string rlabel=toLower(rhs.d_label);
    
    return 
      tie(llabel,     d_type,     d_class, lzrp) ==
      tie(rlabel, rhs.d_type, rhs.d_class, rzrp);
  }
};

//! This class can be used to parse incoming packets, and is copyable
class MOADNSParser : public boost::noncopyable
{
public:
  //! Parse from a string
  MOADNSParser(const string& buffer)  : d_tsigPos(0)
  {
    init(buffer.c_str(), (unsigned int)buffer.size());
  }

  //! Parse from a pointer and length
  MOADNSParser(const char *packet, unsigned int len) : d_tsigPos(0)
  {
    init(packet, len);
  }

  dnsheader d_header;
  string d_qname;
  uint16_t d_qclass, d_qtype;
  uint8_t d_rcode;

  typedef vector<pair<DNSRecord, uint16_t > > answers_t;
  
  //! All answers contained in this packet
  answers_t d_answers;

  shared_ptr<PacketReader> getPacketReader(uint16_t offset)
  {
    shared_ptr<PacketReader> pr(new PacketReader(d_content));
    pr->d_pos=offset;
    return pr;
  }

  uint16_t getTSIGPos()
  {
    return d_tsigPos;
  }
private:
  void getDnsrecordheader(struct dnsrecordheader &ah);
  void init(const char *packet, unsigned int len);
  vector<uint8_t> d_content;
  uint16_t d_tsigPos;
};

string simpleCompress(const string& label, const string& root="");
void simpleExpandTo(const string& label, unsigned int frompos, string& ret);

#endif