File: dnsname.hh

package info (click to toggle)
pdns-recursor 4.0.4-1+deb9u3~bpo8+1
  • links: PTS, VCS
  • area: main
  • in suites: jessie-backports
  • size: 5,484 kB
  • sloc: cpp: 36,380; sh: 11,771; makefile: 305; xml: 37
file content (301 lines) | stat: -rw-r--r-- 10,625 bytes parent folder | download
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
/*
 * This file is part of PowerDNS or dnsdist.
 * Copyright -- PowerDNS.COM B.V. and its contributors
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of version 2 of the GNU General Public License as
 * published by the Free Software Foundation.
 *
 * In addition, for the avoidance of any doubt, permission is granted to
 * link this program with OpenSSL and to (re)distribute the binaries
 * produced as the result of such linking.
 *
 * 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 Street, Fifth Floor, Boston, MA 02110-1301 USA.
 */
#pragma once
#include <string>
#include <vector>
#include <set>
#include <deque>
#include <strings.h>
#include <stdexcept>

#include <boost/version.hpp>

// it crashes on OSX and doesn't compile on OpenBSD
#if BOOST_VERSION >= 105300 && ! defined( __APPLE__ ) && ! defined(__OpenBSD__)
#include <boost/container/string.hpp>
#endif

uint32_t burtleCI(const unsigned char* k, uint32_t lengh, uint32_t init);

// #include "dns.hh"
// #include "logger.hh"

//#include <ext/vstring.h>

/* Quest in life: 
     accept escaped ascii presentations of DNS names and store them "natively"
     accept a DNS packet with an offset, and extract a DNS name from it
     build up DNSNames with prepend and append of 'raw' unescaped labels

   Be able to turn them into ASCII and "DNS name in a packet" again on request

   Provide some common operators for comparison, detection of being part of another domain 

   NOTE: For now, everything MUST be . terminated, otherwise it is an error
*/

inline char dns2_tolower(char c)
{
  if(c>='A' && c<='Z')
    c+='a'-'A';
  return c;
}

class DNSName
{
public:
  DNSName()  {}          //!< Constructs an *empty* DNSName, NOT the root!
  explicit DNSName(const char* p);      //!< Constructs from a human formatted, escaped presentation
  explicit DNSName(const std::string& str) : DNSName(str.c_str()) {}; //!< Constructs from a human formatted, escaped presentation
  DNSName(const char* p, int len, int offset, bool uncompress, uint16_t* qtype=0, uint16_t* qclass=0, unsigned int* consumed=0, uint16_t minOffset=0); //!< Construct from a DNS Packet, taking the first question if offset=12
  
  bool isPartOf(const DNSName& rhs) const;   //!< Are we part of the rhs name?
  bool operator==(const DNSName& rhs) const; //!< DNS-native comparison (case insensitive) - empty compares to empty
  bool operator!=(const DNSName& other) const { return !(*this == other); }

  std::string toString(const std::string& separator=".", const bool trailing=true) const;              //!< Our human-friendly, escaped, representation
  std::string toLogString() const; //!< like plain toString, but returns (empty) on empty names
  std::string toStringNoDot() const { return toString(".", false); }
  std::string toStringRootDot() const { if(isRoot()) return "."; else return toString(".", false); }
  std::string toDNSString() const;           //!< Our representation in DNS native format
  std::string toDNSStringLC() const;           //!< Our representation in DNS native format, lower cased
  void appendRawLabel(const std::string& str); //!< Append this unescaped label
  void appendRawLabel(const char* start, unsigned int length); //!< Append this unescaped label
  void prependRawLabel(const std::string& str); //!< Prepend this unescaped label
  std::vector<std::string> getRawLabels() const; //!< Individual raw unescaped labels
  bool chopOff();                               //!< Turn www.powerdns.com. into powerdns.com., returns false for .
  DNSName makeRelative(const DNSName& zone) const;
  DNSName makeLowerCase() const
  {
    DNSName ret;
    ret.d_storage = d_storage;
    for(auto & c : ret.d_storage) {
      c=dns2_tolower(c);
    }
    return ret;
  }
  void makeUsRelative(const DNSName& zone);
  DNSName labelReverse() const;
  bool isWildcard() const;
  unsigned int countLabels() const;
  size_t wirelength() const; //!< Number of total bytes in the name
  bool empty() const { return d_storage.empty(); }
  bool isRoot() const { return d_storage.size()==1 && d_storage[0]==0; }
  void clear() { d_storage.clear(); }
  void trimToLabels(unsigned int);
  size_t hash(size_t init=0) const
  {
    return burtleCI((const unsigned char*)d_storage.c_str(), d_storage.size(), init);
  }
  DNSName& operator+=(const DNSName& rhs)
  {
    if(d_storage.size() + rhs.d_storage.size() > 256) // one extra byte for the second root label
      throw std::range_error("name too long");
    if(rhs.empty())
      return *this;

    if(d_storage.empty())
      d_storage+=rhs.d_storage;
    else
      d_storage.replace(d_storage.length()-1, rhs.d_storage.length(), rhs.d_storage);

    return *this;
  }

  bool operator<(const DNSName& rhs)  const // this delivers _some_ kind of ordering, but not one useful in a DNS context. Really fast though.
  {
    return std::lexicographical_compare(d_storage.rbegin(), d_storage.rend(), 
				 rhs.d_storage.rbegin(), rhs.d_storage.rend(),
				 [](const char& a, const char& b) {
					  return dns2_tolower(a) < dns2_tolower(b); 
					}); // note that this is case insensitive, including on the label lengths
  }

  inline bool canonCompare(const DNSName& rhs) const;
  bool slowCanonCompare(const DNSName& rhs) const;  

#if BOOST_VERSION >= 105300 && ! defined( __APPLE__ ) && ! defined(__OpenBSD__)
  typedef boost::container::string string_t;
#else
  typedef std::string string_t;
#endif

private:
  string_t d_storage;

  void packetParser(const char* p, int len, int offset, bool uncompress, uint16_t* qtype, uint16_t* qclass, unsigned int* consumed, int depth, uint16_t minOffset);
  static std::string escapeLabel(const std::string& orig);
  static std::string unescapeLabel(const std::string& orig);
};

size_t hash_value(DNSName const& d);


inline bool DNSName::canonCompare(const DNSName& rhs) const
{
  //      01234567890abcd
  // us:  1a3www4ds9a2nl
  // rhs: 3www6online3com
  // to compare, we start at the back, is nl < com? no -> done
  //
  // 0,2,6,a
  // 0,4,a
  
  uint8_t ourpos[64], rhspos[64];
  uint8_t ourcount=0, rhscount=0;
  //cout<<"Asked to compare "<<toString()<<" to "<<rhs.toString()<<endl;
  for(const unsigned char* p = (const unsigned char*)d_storage.c_str(); p < (const unsigned char*)d_storage.c_str() + d_storage.size() && *p && ourcount < sizeof(ourpos); p+=*p+1)
    ourpos[ourcount++]=(p-(const unsigned char*)d_storage.c_str());
  for(const unsigned char* p = (const unsigned char*)rhs.d_storage.c_str(); p < (const unsigned char*)rhs.d_storage.c_str() + rhs.d_storage.size() && *p && rhscount < sizeof(rhspos); p+=*p+1)
    rhspos[rhscount++]=(p-(const unsigned char*)rhs.d_storage.c_str());

  if(ourcount == sizeof(ourpos) || rhscount==sizeof(rhspos)) {
    return slowCanonCompare(rhs);
  }
  
  for(;;) {
    if(ourcount == 0 && rhscount != 0)
      return true;
    if(ourcount == 0 && rhscount == 0)
      return false;
    if(ourcount !=0 && rhscount == 0)
      return false;
    ourcount--;
    rhscount--;

    bool res=std::lexicographical_compare(
					  d_storage.c_str() + ourpos[ourcount] + 1, 
					  d_storage.c_str() + ourpos[ourcount] + 1 + *(d_storage.c_str() + ourpos[ourcount]),
					  rhs.d_storage.c_str() + rhspos[rhscount] + 1, 
					  rhs.d_storage.c_str() + rhspos[rhscount] + 1 + *(rhs.d_storage.c_str() + rhspos[rhscount]),
					  [](const char& a, const char& b) {
					    return dns2_tolower(a) < dns2_tolower(b); 
					  });
    
    //    cout<<"Forward: "<<res<<endl;
    if(res)
      return true;

    res=std::lexicographical_compare(	  rhs.d_storage.c_str() + rhspos[rhscount] + 1, 
					  rhs.d_storage.c_str() + rhspos[rhscount] + 1 + *(rhs.d_storage.c_str() + rhspos[rhscount]),
					  d_storage.c_str() + ourpos[ourcount] + 1, 
					  d_storage.c_str() + ourpos[ourcount] + 1 + *(d_storage.c_str() + ourpos[ourcount]),
					  [](const char& a, const char& b) {
					    return dns2_tolower(a) < dns2_tolower(b); 
					  });
    //    cout<<"Reverse: "<<res<<endl;
    if(res)
      return false;
  }
  return false;
}


struct CanonDNSNameCompare: public std::binary_function<DNSName, DNSName, bool>
{
  bool operator()(const DNSName&a, const DNSName& b) const
  {
    return a.canonCompare(b);
  }
};

inline DNSName operator+(const DNSName& lhs, const DNSName& rhs)
{
  DNSName ret=lhs;
  ret += rhs;
  return ret;
}

/* Quest in life: serve as a rapid block list. If you add a DNSName to a root SuffixMatchNode, 
   anything part of that domain will return 'true' in check */
struct SuffixMatchNode
{
  SuffixMatchNode(const std::string& name_="", bool endNode_=false) : name(name_), endNode(endNode_)
  {}
  std::string name;
  std::string d_human;
  mutable std::set<SuffixMatchNode> children;
  mutable bool endNode;
  bool operator<(const SuffixMatchNode& rhs) const
  {
    return strcasecmp(name.c_str(), rhs.name.c_str()) < 0;
  }

  void add(const DNSName& name) 
  {
    if(!d_human.empty())
      d_human.append(", ");
    d_human += name.toString();
    add(name.getRawLabels());
  }

  void add(std::vector<std::string> labels) const
  {
    if(labels.empty()) { // this allows insertion of the root
      endNode=true;
    }
    else if(labels.size()==1) {
      children.insert(SuffixMatchNode(*labels.begin(), true));
    }
    else {
      auto res=children.insert(SuffixMatchNode(*labels.rbegin(), false));
      labels.pop_back();
      res.first->add(labels);
    }
  }

  bool check(const DNSName& name)  const
  {
    if(children.empty()) // speed up empty set
      return endNode;
    return check(name.getRawLabels());
  }

  bool check(std::vector<std::string> labels) const
  {
    if(labels.empty()) // optimization
      return endNode; 

    SuffixMatchNode smn(*labels.rbegin());
    auto child = children.find(smn);
    if(child == children.end())
      return endNode;
    labels.pop_back();
    return child->check(labels);
  }
  
  std::string toString() const
  {
    return d_human;
  }

};

std::ostream & operator<<(std::ostream &os, const DNSName& d);
namespace std {
    template <>
    struct hash<DNSName> {
        size_t operator () (const DNSName& dn) const { return dn.hash(0); }
    };
}

DNSName::string_t segmentDNSNameRaw(const char* input); // from ragel