pdns/dnspacket.hh

   1 /*
   2  * This file is part of PowerDNS or dnsdist.
   3  * Copyright -- PowerDNS.COM B.V. and its contributors
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of version 2 of the GNU General Public License as
   7  * published by the Free Software Foundation.
   8  *
   9  * In addition, for the avoidance of any doubt, permission is granted to
  10  * link this program with OpenSSL and to (re)distribute the binaries
  11  * produced as the result of such linking.
  12  *
  13  * This program is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16  * GNU General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU General Public License
  19  * along with this program; if not, write to the Free Software
  20  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  21  */
  22 #ifndef DNSPACKET_HH
  23
  24 #define DNSPACKET_HH
  25
  26 #include <cstdio>
  27 #include <cstring>
  28 #include <cstdlib>
  29 #include <sys/types.h>
  30 #include "iputils.hh"
  31 #include "ednssubnet.hh"
  32 #include <unordered_set>
  33 #include <sys/socket.h>
  34 #include <netinet/in.h>
  35 #include <sys/time.h>
  36 #include <unistd.h>
  37 #include <arpa/inet.h>
  38
  39 #include <iostream>
  40 #include <string>
  41 #include <vector>
  42 #include "qtype.hh"
  43 #include "dns.hh"
  44 #include "misc.hh"
  45 #include "utility.hh"
  46 #include "logger.hh"
  47 #include "pdnsexception.hh"
  48 #include "dnsrecords.hh"
  49
  50 class UeberBackend;
  51 class DNSSECKeeper;
  52
  53
  54 //! This class represents DNS packets, either received or to be sent.
  55 class DNSPacket
  56 {
  57 public:
  58   DNSPacket(bool isQuery);
  59   DNSPacket(const DNSPacket &orig);
  60
  61   int noparse(const char *mesg, size_t len); //!< just suck the data inward
  62   int parse(const char *mesg, size_t len); //!< parse a raw UDP or TCP packet and suck the data inward
  63   const string& getString(); //!< for serialization - just passes the whole packet
  64
  65   // address & socket manipulation
  66   void setRemote(const ComboAddress*);
  67   ComboAddress getRemote() const;
  68   Netmask getRealRemote() const;
  69   ComboAddress getLocal() const
  70   {
  71     ComboAddress ca;
  72     socklen_t len=sizeof(ca);
  73     getsockname(d_socket, (sockaddr*)&ca, &len);
  74     return ca;
  75   }
  76   uint16_t getRemotePort() const;
  77
  78   boost::optional<ComboAddress> d_anyLocal;
  79
  80   Utility::sock_t getSocket() const
  81   {
  82     return d_socket;
  83   }
  84   void setSocket(Utility::sock_t sock);
  85
  86
  87   // these manipulate 'd'
  88   void setA(bool); //!< make this packet authoritative - manipulates 'd'
  89   void setID(uint16_t); //!< set the DNS id of this packet - manipulates 'd'
  90   void setRA(bool); //!< set the Recursion Available flag - manipulates 'd'
  91   void setRD(bool); //!< set the Recursion Desired flag - manipulates 'd'
  92   void setAnswer(bool); //!< Make this packet an answer - clears the 'stringbuffer' first, if passed 'true', does nothing otherwise, manipulates 'd'
  93
  94   void setOpcode(uint16_t);  //!< set the Opcode of this packet - manipulates 'd'
  95   void setRcode(int v); //!< set the Rcode of this packet - manipulates 'd'
  96
  97   void clearRecords(); //!< when building a packet, wipe all previously added records (clears 'rrs')
  98
  99   /** Add a DNSZoneRecord to this packet. A DNSPacket (as does a DNS Packet) has 4 kinds of resource records. Questions,
 100       Answers, Authority and Additional. See RFC 1034 and 1035 for details. You can specify where a record needs to go in the
 101       DNSZoneRecord d_place field */
 102   void addRecord(const DNSZoneRecord &);  // adds to 'rrs'
 103
 104   void setQuestion(int op, const DNSName &qdomain, int qtype);  // wipes 'd', sets a random id, creates start of packet (domain, type, class etc)
 105
 106   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
 107   void wrapup();  // writes out queued rrs, and generates the binary packet. also shuffles. also rectifies dnsheader 'd', and copies it to the stringbuffer
 108   void spoofQuestion(const DNSPacket *qd); //!< paste in the exact right case of the question. Useful for PacketCache
 109   unsigned int getMinTTL(); //!< returns lowest TTL of any record in the packet
 110   bool isEmpty(); //!< returns true if there are no rrs in the packet
 111
 112   vector<DNSZoneRecord*> getAPRecords(); //!< get a vector with DNSZoneRecords that need additional processing
 113   vector<DNSZoneRecord*> getAnswerRecords(); //!< get a vector with DNSZoneRecords that are answers
 114   void setCompress(bool compress);
 115
 116   DNSPacket *replyPacket() const; //!< convenience function that creates a virgin answer packet to this question
 117
 118   void commitD(); //!< copies 'd' into the stringbuffer
 119   unsigned int getMaxReplyLen(); //!< retrieve the maximum length of the packet we should send in response
 120   void setMaxReplyLen(int bytes); //!< set the max reply len (used when retrieving from the packet cache, and this changed)
 121
 122   bool couldBeCached(); //!< returns 0 if this query should bypass the packet cache
 123   bool hasEDNSSubnet() const;
 124   bool hasEDNS();
 125   uint8_t getEDNSVersion() const { return d_ednsversion; };
 126   void setEDNSRcode(uint16_t extRCode)
 127   {
 128     // WARNING: this is really 12 bits
 129     d_ednsrcode=extRCode;
 130   };
 131   uint8_t getEDNSRCode() const { return d_ednsrcode; };
 132   uint32_t getHash() const { return d_hash; };
 133   void setHash(uint32_t hash) { d_hash = hash; };
 134
 135   //////// DATA !
 136
 137   DNSName qdomain;  //!< qname of the question 4 - unsure how this is used
 138   DNSName qdomainwild;  //!< wildcard matched by qname, used by LuaPolicyEngine
 139   DNSName qdomainzone;  //!< zone name for the answer (as reflected in SOA for negative responses), used by LuaPolicyEngine
 140   string d_peer_principal;
 141   const DNSName& getTSIGKeyname() const;
 142
 143   struct dnsheader d; //!< dnsheader at the start of the databuffer 12
 144
 145   TSIGRecordContent d_trc; //72
 146
 147   ComboAddress d_remote; //28
 148   TSIGHashEnum d_tsig_algo{TSIG_MD5}; //4
 149
 150   int d_ednsRawPacketSizeLimit{-1}; // only used for Lua record
 151   uint16_t qclass{QClass::IN};  //!< class of the question - should always be INternet 2
 152   QType qtype;  //!< type of the question 2
 153
 154   bool d_tcp{false};
 155   bool d_dnssecOk{false};
 156   bool d_havetsig{false};
 157
 158   bool getTSIGDetails(TSIGRecordContent* tr, DNSName* keyname, uint16_t* tsigPos=nullptr) const;
 159   void setTSIGDetails(const TSIGRecordContent& tr, const DNSName& keyname, const string& secret, const string& previous, bool timersonly=false);
 160   bool getTKEYRecord(TKEYRecordContent* tr, DNSName* keyname) const;
 161
 162   vector<DNSZoneRecord>& getRRS() { return d_rrs; }
 163   bool checkForCorrectTSIG(UeberBackend* B, DNSName* keyname, string* secret, TSIGRecordContent* trc) const;
 164
 165   static uint16_t s_udpTruncationThreshold;
 166   static bool s_doEDNSSubnetProcessing;
 167
 168 private:
 169   void pasteQ(const char *question, int length); //!< set the question of this packet, useful for crafting replies
 170
 171   string d_tsigsecret;
 172   DNSName d_tsigkeyname;
 173   string d_tsigprevious;
 174
 175   vector<DNSZoneRecord> d_rrs; // 8
 176   std::unordered_set<size_t> d_dedup;
 177   string d_rawpacket; // this is where everything lives 8
 178   EDNSSubnetOpts d_eso;
 179
 180   int d_maxreplylen{0};
 181   int d_socket{-1}; // 4
 182   uint32_t d_hash{0};
 183   // WARNING! This is really 12 bits
 184   uint16_t d_ednsrcode{0};
 185   uint8_t d_ednsversion{0};
 186
 187   bool d_wrapped{false}; // 1
 188   bool d_compress{true}; // 1
 189   bool d_tsigtimersonly{false};
 190   bool d_wantsnsid{false};
 191   bool d_haveednssubnet{false};
 192   bool d_haveednssection{false};
 193   bool d_isQuery;
 194 };
 195
 196 #endif