pdns/dns.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 #pragma once
  23 #include "qtype.hh"
  24 #include "dnsname.hh"
  25 #include <ctime>
  26 #include <sys/types.h>
  27
  28 #undef BADSIG  // signal.h SIG_ERR
  29
  30 struct DNSRecord;
  31
  32 class RCode
  33 {
  34 public:
  35   enum rcodes_ { NoError=0, FormErr=1, ServFail=2, NXDomain=3, NotImp=4, Refused=5, YXDomain=6, YXRRSet=7, NXRRSet=8, NotAuth=9, NotZone=10};
  36   static std::string to_s(uint8_t rcode);
  37   static std::string to_short_s(uint8_t rcode);
  38   const static std::array<std::string, 24> rcodes_s;
  39 };
  40
  41 class ERCode
  42 {
  43 public:
  44   enum rcodes_ { BADVERS=16, BADSIG=16, BADKEY=17, BADTIME=18, BADMODE=19, BADNAME=20, BADALG=21, BADTRUNC=22, BADCOOKIE=23 };
  45   static std::string to_s(uint8_t rcode);
  46 };
  47
  48 class Opcode
  49 {
  50 public:
  51   enum { Query=0, IQuery=1, Status=2, Notify=4, Update=5 };
  52   static std::string to_s(uint8_t opcode);
  53 };
  54
  55 //! This class represents a resource record
  56 class DNSResourceRecord
  57 {
  58 public:
  59   DNSResourceRecord() : last_modified(0), ttl(0), signttl(0), domain_id(-1), qclass(1), scopeMask(0), auth(1), disabled(0) {};
  60   static DNSResourceRecord fromWire(const DNSRecord& d);
  61
  62   enum Place : uint8_t {QUESTION=0, ANSWER=1, AUTHORITY=2, ADDITIONAL=3}; //!< Type describing the positioning within, say, a DNSPacket
  63
  64   void setContent(const string& content);
  65   string getZoneRepresentation(bool noDot=false) const;
  66
  67   // data
  68   DNSName qname; //!< the name of this record, for example: www.powerdns.com
  69   DNSName ordername;
  70   DNSName wildcardname;
  71   string content; //!< what this record points to. Example: 10.1.2.3
  72
  73   // Aligned on 8-byte boundaries on systems where time_t is 8 bytes and int
  74   // is 4 bytes, aka modern linux on x86_64
  75   time_t last_modified; //!< For autocalculating SOA serial numbers - the backend needs to fill this in
  76
  77   uint32_t ttl; //!< Time To Live of this record
  78   uint32_t signttl; //!< If non-zero, use this TTL as original TTL in the RRSIG
  79
  80   int domain_id; //!< If a backend implements this, the domain_id of the zone this record is in
  81   QType qtype; //!< qtype of this record, ie A, CNAME, MX etc
  82   uint16_t qclass; //!< class of this record
  83
  84   uint8_t scopeMask;
  85   bool auth;
  86   bool disabled;
  87
  88   bool operator==(const DNSResourceRecord& rhs);
  89
  90   bool operator<(const DNSResourceRecord &b) const
  91   {
  92     if(qname < b.qname)
  93       return true;
  94     if(qname == b.qname)
  95       return(content < b.content);
  96     return false;
  97   }
  98 };
  99
 100 #define GCCPACKATTRIBUTE __attribute__((packed))
 101
 102 struct dnsrecordheader
 103 {
 104   uint16_t d_type;
 105   uint16_t d_class;
 106   uint32_t d_ttl;
 107   uint16_t d_clen;
 108 } GCCPACKATTRIBUTE;
 109
 110 struct EDNS0Record
 111 {
 112   uint8_t extRCode, version;
 113   uint16_t extFlags;
 114 } GCCPACKATTRIBUTE;
 115
 116 static_assert(sizeof(EDNS0Record) == 4, "EDNS0Record size must be 4");
 117
 118 #if defined(__FreeBSD__) || defined(__APPLE__) || defined(__OpenBSD__) || defined(__DragonFly__) || defined(__FreeBSD_kernel__) || defined(__NetBSD__)
 119 #include <machine/endian.h>
 120 #elif __linux__ || __GNU__
 121 # include <endian.h>
 122
 123 #else  // with thanks to <arpa/nameser.h>
 124
 125 # define LITTLE_ENDIAN   1234    /* least-significant byte first (vax, pc) */
 126 # define BIG_ENDIAN      4321    /* most-significant byte first (IBM, net) */
 127 # define PDP_ENDIAN      3412    /* LSB first in word, MSW first in long (pdp) */
 128
 129 #if defined(vax) || defined(ns32000) || defined(sun386) || defined(i386) || \
 130         defined(__i386) || defined(__ia64) || defined(__amd64) || \
 131         defined(MIPSEL) || defined(_MIPSEL) || defined(BIT_ZERO_ON_RIGHT) || \
 132         defined(__alpha__) || defined(__alpha) || \
 133         (defined(__Lynx__) && defined(__x86__))
 134 # define BYTE_ORDER      LITTLE_ENDIAN
 135 #endif
 136
 137 #if defined(sel) || defined(pyr) || defined(mc68000) || defined(sparc) || \
 138     defined(__sparc) || \
 139     defined(is68k) || defined(tahoe) || defined(ibm032) || defined(ibm370) || \
 140     defined(MIPSEB) || defined(_MIPSEB) || defined(_IBMR2) || defined(DGUX) ||\
 141     defined(apollo) || defined(__convex__) || defined(_CRAY) || \
 142     defined(__hppa) || defined(__hp9000) || \
 143     defined(__hp9000s300) || defined(__hp9000s700) || \
 144     defined(__hp3000s900) || defined(MPE) || \
 145     defined(BIT_ZERO_ON_LEFT) || defined(m68k) || \
 146         (defined(__Lynx__) && \
 147         (defined(__68k__) || defined(__sparc__) || defined(__powerpc__)))
 148 # define BYTE_ORDER      BIG_ENDIAN
 149 #endif
 150
 151 #endif
 152
 153 struct dnsheader {
 154         unsigned        id :16;         /* query identification number */
 155 #if BYTE_ORDER == BIG_ENDIAN
 156                         /* fields in third byte */
 157         unsigned        qr: 1;          /* response flag */
 158         unsigned        opcode: 4;      /* purpose of message */
 159         unsigned        aa: 1;          /* authoritative answer */
 160         unsigned        tc: 1;          /* truncated message */
 161         unsigned        rd: 1;          /* recursion desired */
 162                         /* fields in fourth byte */
 163         unsigned        ra: 1;          /* recursion available */
 164         unsigned        unused :1;      /* unused bits (MBZ as of 4.9.3a3) */
 165         unsigned        ad: 1;          /* authentic data from named */
 166         unsigned        cd: 1;          /* checking disabled by resolver */
 167         unsigned        rcode :4;       /* response code */
 168 #elif BYTE_ORDER == LITTLE_ENDIAN || BYTE_ORDER == PDP_ENDIAN
 169                         /* fields in third byte */
 170         unsigned        rd :1;          /* recursion desired */
 171         unsigned        tc :1;          /* truncated message */
 172         unsigned        aa :1;          /* authoritative answer */
 173         unsigned        opcode :4;      /* purpose of message */
 174         unsigned        qr :1;          /* response flag */
 175                         /* fields in fourth byte */
 176         unsigned        rcode :4;       /* response code */
 177         unsigned        cd: 1;          /* checking disabled by resolver */
 178         unsigned        ad: 1;          /* authentic data from named */
 179         unsigned        unused :1;      /* unused bits (MBZ as of 4.9.3a3) */
 180         unsigned        ra :1;          /* recursion available */
 181 #endif
 182                         /* remaining bytes */
 183         unsigned        qdcount :16;    /* number of question entries */
 184         unsigned        ancount :16;    /* number of answer entries */
 185         unsigned        nscount :16;    /* number of authority entries */
 186         unsigned        arcount :16;    /* number of resource entries */
 187 };
 188
 189 static_assert(sizeof(dnsheader) == 12, "dnsheader size must be 12");
 190
 191 class dnsheader_aligned
 192 {
 193 public:
 194   dnsheader_aligned(const void* mem)
 195   {
 196     if (reinterpret_cast<uintptr_t>(mem) % sizeof(uint32_t) == 0) {
 197       d_p = reinterpret_cast<const dnsheader*>(mem);
 198     }
 199     else {
 200       memcpy(&d_h, mem, sizeof(dnsheader));
 201       d_p = &d_h;
 202     }
 203   }
 204
 205   const dnsheader* get() const
 206   {
 207     return d_p;
 208   }
 209
 210 private:
 211   dnsheader d_h;
 212   const dnsheader *d_p;
 213 };
 214
 215 inline uint16_t * getFlagsFromDNSHeader(struct dnsheader * dh)
 216 {
 217   return (uint16_t*) (((char *) dh) + sizeof(uint16_t));
 218 }
 219
 220 #define DNS_TYPE_SIZE (2)
 221 #define DNS_CLASS_SIZE (2)
 222 #define DNS_TTL_SIZE (4)
 223 #define DNS_RDLENGTH_SIZE (2)
 224 #define EDNS_EXTENDED_RCODE_SIZE (1)
 225 #define EDNS_VERSION_SIZE (1)
 226 #define EDNS_OPTION_CODE_SIZE (2)
 227 #define EDNS_OPTION_LENGTH_SIZE (2)
 228
 229 #if BYTE_ORDER == BIG_ENDIAN
 230 #define FLAGS_RD_OFFSET (8)
 231 #define FLAGS_CD_OFFSET (12)
 232 #elif BYTE_ORDER == LITTLE_ENDIAN || BYTE_ORDER == PDP_ENDIAN
 233 #define FLAGS_RD_OFFSET (0)
 234 #define FLAGS_CD_OFFSET (12)
 235 #endif
 236
 237 uint32_t hashQuestion(const uint8_t* packet, uint16_t len, uint32_t init, bool& ok);
 238
 239 struct TSIGTriplet
 240 {
 241   DNSName name, algo;
 242   string secret;
 243 };