src/dns-protocol.h

   1 /* dnsmasq is Copyright (c) 2000-2015 Simon Kelley
   2
   3    This program is free software; you can redistribute it and/or modify
   4    it under the terms of the GNU General Public License as published by
   5    the Free Software Foundation; version 2 dated June, 1991, or
   6    (at your option) version 3 dated 29 June, 2007.
   7
   8    This program is distributed in the hope that it will be useful,
   9    but WITHOUT ANY WARRANTY; without even the implied warranty of
  10    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  11    GNU General Public License for more details.
  12
  13    You should have received a copy of the GNU General Public License
  14    along with this program.  If not, see <http://www.gnu.org/licenses/>.
  15 */
  16
  17 #define NAMESERVER_PORT 53
  18 #define TFTP_PORT       69
  19
  20 #define IN6ADDRSZ       16
  21 #define INADDRSZ        4
  22
  23 #define PACKETSZ        512             /* maximum packet size */
  24 #define MAXDNAME        1025            /* maximum presentation domain name */
  25 #define RRFIXEDSZ       10              /* #/bytes of fixed data in r record */
  26 #define MAXLABEL        63              /* maximum length of domain label */
  27
  28 #define NOERROR         0               /* no error */
  29 #define FORMERR         1               /* format error */
  30 #define SERVFAIL        2               /* server failure */
  31 #define NXDOMAIN        3               /* non existent domain */
  32 #define NOTIMP          4               /* not implemented */
  33 #define REFUSED         5               /* query refused */
  34
  35 #define QUERY           0               /* opcode */
  36
  37 #define C_IN            1               /* the arpa internet */
  38 #define C_CHAOS         3               /* for chaos net (MIT) */
  39 #define C_HESIOD        4               /* hesiod */
  40 #define C_ANY           255             /* wildcard match */
  41
  42 #define T_A             1
  43 #define T_NS            2
  44 #define T_MD            3
  45 #define T_MF            4
  46 #define T_CNAME         5
  47 #define T_SOA           6
  48 #define T_MB            7
  49 #define T_MG            8
  50 #define T_MR            9
  51 #define T_PTR           12
  52 #define T_MINFO         14
  53 #define T_MX            15
  54 #define T_TXT           16
  55 #define T_RP            17
  56 #define T_AFSDB         18
  57 #define T_RT            21
  58 #define T_SIG           24
  59 #define T_PX            26
  60 #define T_AAAA          28
  61 #define T_NXT           30
  62 #define T_SRV           33
  63 #define T_NAPTR         35
  64 #define T_KX            36
  65 #define T_DNAME         39
  66 #define T_OPT           41
  67 #define T_DS            43
  68 #define T_RRSIG         46
  69 #define T_NSEC          47
  70 #define T_DNSKEY        48
  71 #define T_NSEC3         50
  72 #define T_TKEY          249
  73 #define T_TSIG          250
  74 #define T_AXFR          252
  75 #define T_MAILB         253
  76 #define T_ANY           255
  77
  78 #define EDNS0_OPTION_MAC            65001 /* dyndns.org temporary assignment */
  79 #define EDNS0_OPTION_CLIENT_SUBNET  8     /* IANA */
  80
  81 struct dns_header {
  82   u16 id;
  83   u8  hb3,hb4;
  84   u16 qdcount,ancount,nscount,arcount;
  85 };
  86
  87 #define HB3_QR       0x80
  88 #define HB3_OPCODE   0x78
  89 #define HB3_AA       0x04
  90 #define HB3_TC       0x02
  91 #define HB3_RD       0x01
  92
  93 #define HB4_RA       0x80
  94 #define HB4_AD       0x20
  95 #define HB4_CD       0x10
  96 #define HB4_RCODE    0x0f
  97
  98 #define OPCODE(x)          (((x)->hb3 & HB3_OPCODE) >> 3)
  99 #define SET_OPCODE(x, code) (x)->hb3 = ((x)->hb3 & ~HB3_OPCODE) | code
 100
 101 #define RCODE(x)           ((x)->hb4 & HB4_RCODE)
 102 #define SET_RCODE(x, code) (x)->hb4 = ((x)->hb4 & ~HB4_RCODE) | code
 103
 104 #define GETSHORT(s, cp) { \
 105         unsigned char *t_cp = (unsigned char *)(cp); \
 106         (s) = ((u16)t_cp[0] << 8) \
 107             | ((u16)t_cp[1]) \
 108             ; \
 109         (cp) += 2; \
 110 }
 111
 112 #define GETLONG(l, cp) { \
 113         unsigned char *t_cp = (unsigned char *)(cp); \
 114         (l) = ((u32)t_cp[0] << 24) \
 115             | ((u32)t_cp[1] << 16) \
 116             | ((u32)t_cp[2] << 8) \
 117             | ((u32)t_cp[3]) \
 118             ; \
 119         (cp) += 4; \
 120 }
 121
 122 #define PUTSHORT(s, cp) { \
 123         u16 t_s = (u16)(s); \
 124         unsigned char *t_cp = (unsigned char *)(cp); \
 125         *t_cp++ = t_s >> 8; \
 126         *t_cp   = t_s; \
 127         (cp) += 2; \
 128 }
 129
 130 #define PUTLONG(l, cp) { \
 131         u32 t_l = (u32)(l); \
 132         unsigned char *t_cp = (unsigned char *)(cp); \
 133         *t_cp++ = t_l >> 24; \
 134         *t_cp++ = t_l >> 16; \
 135         *t_cp++ = t_l >> 8; \
 136         *t_cp   = t_l; \
 137         (cp) += 4; \
 138 }
 139
 140 #define CHECK_LEN(header, pp, plen, len) \
 141     ((size_t)((pp) - (unsigned char *)(header) + (len)) <= (plen))
 142
 143 #define ADD_RDLEN(header, pp, plen, len) \
 144   (!CHECK_LEN(header, pp, plen, len) ? 0 : (((pp) += (len)), 1))