pdns/dnspacket.hh

   1 /*
   2     PowerDNS Versatile Database Driven Nameserver
   3     Copyright (C) 2002 - 2005  PowerDNS.COM BV
   4
   5     This program is free software; you can redistribute it and/or modify it
   6     under the terms of the GNU General Public License version 2 as published
   7     by the Free Software Foundation
   8
   9     This program is distributed in the hope that it will be useful,
  10     but WITHOUT ANY WARRANTY; without even the implied warranty of
  11     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12     GNU General Public License for more details.
  13
  14     You should have received a copy of the GNU General Public License
  15     along with this program; if not, write to the Free Software
  16     Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  17 */
  18 #ifndef DNSPACKET_HH
  19
  20 #if __GNUC__ == 2
  21 #if __GNUC_MINOR__ < 95
  22         #error Your compiler is too old! Try g++ 3.3 or higher
  23 #else
  24         #warning There are known problems with PowerDNS binaries compiled by gcc version 2.95 and 2.96!
  25 #endif
  26 #endif
  27
  28 #define DNSPACKET_HH
  29
  30 #include <cstdio>
  31 #include <cstring>
  32 #include <cstdlib>
  33 #include <sys/types.h>
  34 #include "iputils.hh"
  35
  36 #ifndef WIN32
  37 #include <sys/socket.h>
  38 #include <netinet/in.h>
  39 #include <sys/time.h>
  40 #include <unistd.h>
  41 #include <arpa/inet.h>
  42
  43 #endif // WIN32
  44
  45 #include <iostream>
  46 #include <string>
  47
  48 #include <vector>
  49 #include "qtype.hh"
  50 #include "dns.hh"
  51 #include "misc.hh"
  52 #include "utility.hh"
  53 #include "logger.hh"
  54 #include "ahuexception.hh"
  55
  56 #ifdef HAVE_CONFIG_H
  57 #include "config.h"
  58  #endif // HAVE_CONFIG_H
  59
  60
  61 #ifdef WIN32
  62 # ifdef BYTE_ORDER
  63 #   undef BYTE_ORDER
  64 # endif // BYTE_ORDER
  65 # define BYTE_ORDER LITTLE_ENDIAN
  66 #endif // WIN32
  67
  68 class DNSBackend;
  69
  70 /** helper function for both DNSPacket and addSOARecord() - converts a line into a struct, for easier parsing */
  71 void fillSOAData(const string &content, SOAData &data);
  72
  73 /** for use by DNSPacket, converts a SOAData class to a ascii line again */
  74 string serializeSOAData(const SOAData &data);
  75
  76 string &attodot(string &str);  //!< for when you need to insert an email address in the SOA
  77
  78 //! This class represents DNS packets, either received or to be sent.
  79 class DNSPacket
  80 {
  81 public:
  82   DNSPacket();
  83   DNSPacket(const DNSPacket &orig);
  84
  85   int noparse(const char *mesg, int len); //!< parse a raw UDP or TCP packet and suck the data inward
  86   int parse(const char *mesg, int len); //!< parse a raw UDP or TCP packet and suck the data inward
  87   string getString(); //!< for serialization - just passes the whole packet
  88
  89   // address & socket manipulation
  90   void setRemote(const ComboAddress*);
  91   string getRemote() const;
  92   string getLocal() const
  93   {
  94     ComboAddress ca;
  95     socklen_t len=sizeof(ca);
  96     getsockname(d_socket, (sockaddr*)&ca, &len);
  97     return ca.toString();
  98   }
  99   uint16_t getRemotePort() const;
 100
 101   Utility::sock_t getSocket() const
 102   {
 103     return d_socket;
 104   }
 105   void setSocket(Utility::sock_t sock);
 106
 107
 108   // these manipulate 'd'
 109   void setA(bool); //!< make this packet authoritative - manipulates 'd'
 110   void setID(uint16_t); //!< set the DNS id of this packet - manipulates 'd'
 111   void setRA(bool); //!< set the Recursion Available flag - manipulates 'd'
 112   void setRD(bool); //!< set the Recursion Desired flag - manipulates 'd'
 113   void setAnswer(bool); //!< Make this packet an answer - clears the 'stringbuffer' first, if passed 'true', does nothing otherwise, manipulates 'd'
 114
 115   void setOpcode(uint16_t);  //!< set the Opcode of this packet - manipulates 'd'
 116   void setRcode(int v); //!< set the Rcode of this packet - manipulates 'd'
 117
 118   void clearRecords(); //!< when building a packet, wipe all previously added records (clears 'rrs')
 119
 120   /** Add a DNSResourceRecord to this packet. A DNSPacket (as does a DNS Packet) has 4 kinds of resource records. Questions,
 121       Answers, Authority and Additional. See RFC 1034 and 1035 for details. You can specify where a record needs to go in the
 122       DNSResourceRecord d_place field */
 123   void addRecord(const DNSResourceRecord &);  // adds to 'rrs'
 124
 125   void setQuestion(int op, const string &qdomain, int qtype);  // wipes 'd', sets a random id, creates start of packet (label, type, class etc)
 126
 127   DTime d_dt; //!< the time this packet was created. replyPacket() copies this in for you, so d_dt becomes the time spent processing the question+answer
 128   void wrapup(void);  // writes out queued rrs, and generates the binary packet. also shuffles. also rectifies dnsheader 'd', and copies it to the stringbuffer
 129   const char *getData(void); //!< get binary representation of packet, will call 'wrapup' for you
 130
 131   const char *getRaw(void); //!< provides access to the raw packet, possibly on a packet that has never been 'wrapped'
 132   void spoofID(uint16_t id); //!< change the ID of an existing packet. Useful for fixing up packets returned from the PacketCache
 133   void spoofQuestion(const string &qd); //!< paste in the exact right case of the question. Useful for PacketCache
 134   void truncate(int new_length); // has documentation in source
 135
 136   vector<DNSResourceRecord*> getAPRecords(); //!< get a vector with DNSResourceRecords that need additional processing
 137   void setCompress(bool compress);
 138
 139   DNSPacket *replyPacket() const; //!< convenience function that creates a virgin answer packet to this question
 140
 141   void commitD(); //!< copies 'd' into the stringbuffer
 142   int getMaxReplyLen(); //!< retrieve the maximum length of the packet we should send in response
 143   void setMaxReplyLen(int bytes); //!< set the max reply len (used when retrieving from the packet cache, and this changed)
 144
 145   bool couldBeCached(); //!< returns 0 if this query should bypass the packet cache
 146
 147   //////// DATA !
 148
 149   ComboAddress remote;
 150   uint16_t len; //!< length of the raw binary packet 2
 151   uint16_t qclass;  //!< class of the question - should always be INternet 2
 152   struct dnsheader d; //!< dnsheader at the start of the databuffer 12
 153
 154   QType qtype;  //!< type of the question 8
 155
 156   string qdomain;  //!< qname of the question 4 - unsure how this is used
 157   bool d_tcp;
 158
 159 private:
 160   void pasteQ(const char *question, int length); //!< set the question of this packet, useful for crafting replies
 161
 162   bool d_wrapped; // 1
 163   bool d_compress; // 1
 164   uint16_t d_qlen; // length of the question (including class & type) in this packet 2
 165
 166   int d_socket; // 4
 167
 168   string stringbuffer; // this is where everything lives 4
 169   int d_maxreplylen;
 170   string d_ednsping;
 171   bool d_wantsnsid;
 172   vector<DNSResourceRecord> rrs; // 4
 173 };
 174
 175
 176
 177 #endif