summaryrefslogtreecommitdiff
path: root/src/dns-protocol.h
blob: 4958830aca95b162e30b9a5619bfa2e8409f8849 (plain)
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
/* dnsmasq is Copyright (c) 2000-2018 Simon Kelley

   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; version 2 dated June, 1991, or
   (at your option) version 3 dated 29 June, 2007.
 
   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, see <http://www.gnu.org/licenses/>.
*/

#define NAMESERVER_PORT 53
#define TFTP_PORT       69
#define MIN_PORT        1024           /* first non-reserved port */
#define MAX_PORT        65535u

#define IN6ADDRSZ       16
#define INADDRSZ        4

#define PACKETSZ	512		/* maximum packet size */
#define MAXDNAME	1025		/* maximum presentation domain name */
#define RRFIXEDSZ	10		/* #/bytes of fixed data in r record */
#define MAXLABEL        63              /* maximum length of domain label */

#define NOERROR		0		/* no error */
#define FORMERR		1		/* format error */
#define SERVFAIL	2		/* server failure */
#define NXDOMAIN	3		/* non existent domain */
#define NOTIMP		4		/* not implemented */
#define REFUSED		5		/* query refused */

#define QUERY           0               /* opcode */

#define C_IN            1               /* the arpa internet */
#define C_CHAOS         3               /* for chaos net (MIT) */
#define C_HESIOD        4               /* hesiod */
#define C_ANY           255             /* wildcard match */

#define T_A		1
#define T_NS            2
#define T_MD            3
#define T_MF            4             
#define T_CNAME		5
#define T_SOA		6
#define T_MB            7
#define T_MG            8
#define T_MR            9
#define T_PTR		12
#define T_MINFO         14
#define T_MX		15
#define T_TXT		16
#define T_RP            17
#define T_AFSDB         18
#define T_RT            21
#define T_SIG		24
#define T_PX            26
#define T_AAAA		28
#define T_NXT           30
#define T_SRV		33
#define T_NAPTR		35
#define T_KX            36
#define T_DNAME         39
#define T_OPT		41
#define T_DS            43
#define T_RRSIG         46
#define T_NSEC          47
#define T_DNSKEY        48
#define T_NSEC3         50
#define	T_TKEY		249		
#define	T_TSIG		250
#define T_AXFR          252
#define T_MAILB		253	
#define T_ANY		255

#define EDNS0_OPTION_MAC            65001 /* dyndns.org temporary assignment */
#define EDNS0_OPTION_CLIENT_SUBNET  8     /* IANA */
#define EDNS0_OPTION_NOMDEVICEID    65073 /* Nominum temporary assignment */
#define EDNS0_OPTION_NOMCPEID       65074 /* Nominum temporary assignment */

struct dns_header {
  u16 id;
  u8  hb3,hb4;
  u16 qdcount,ancount,nscount,arcount;
};

#define HB3_QR       0x80 /* Query */
#define HB3_OPCODE   0x78
#define HB3_AA       0x04 /* Authoritative Answer */
#define HB3_TC       0x02 /* TrunCated */
#define HB3_RD       0x01 /* Recursion Desired */

#define HB4_RA       0x80 /* Recursion Available */
#define HB4_AD       0x20 /* Authenticated Data */
#define HB4_CD       0x10 /* Checking Disabled */
#define HB4_RCODE    0x0f

#define OPCODE(x)          (((x)->hb3 & HB3_OPCODE) >> 3)
#define SET_OPCODE(x, code) (x)->hb3 = ((x)->hb3 & ~HB3_OPCODE) | code

#define RCODE(x)           ((x)->hb4 & HB4_RCODE)
#define SET_RCODE(x, code) (x)->hb4 = ((x)->hb4 & ~HB4_RCODE) | code
  
#define GETSHORT(s, cp) { \
	unsigned char *t_cp = (unsigned char *)(cp); \
	(s) = ((u16)t_cp[0] << 8) \
	    | ((u16)t_cp[1]) \
	    ; \
	(cp) += 2; \
}

#define GETLONG(l, cp) { \
	unsigned char *t_cp = (unsigned char *)(cp); \
	(l) = ((u32)t_cp[0] << 24) \
	    | ((u32)t_cp[1] << 16) \
	    | ((u32)t_cp[2] << 8) \
	    | ((u32)t_cp[3]) \
	    ; \
	(cp) += 4; \
}

#define PUTSHORT(s, cp) { \
	u16 t_s = (u16)(s); \
	unsigned char *t_cp = (unsigned char *)(cp); \
	*t_cp++ = t_s >> 8; \
	*t_cp   = t_s; \
	(cp) += 2; \
}

#define PUTLONG(l, cp) { \
	u32 t_l = (u32)(l); \
	unsigned char *t_cp = (unsigned char *)(cp); \
	*t_cp++ = t_l >> 24; \
	*t_cp++ = t_l >> 16; \
	*t_cp++ = t_l >> 8; \
	*t_cp   = t_l; \
	(cp) += 4; \
}

#define CHECK_LEN(header, pp, plen, len) \
    ((size_t)((pp) - (unsigned char *)(header) + (len)) <= (plen))

#define ADD_RDLEN(header, pp, plen, len) \
  (!CHECK_LEN(header, pp, plen, len) ? 0 : (((pp) += (len)), 1))

/* Escape character in our presentation format for names.
   Cannot be '.' or /000 and must be !isprint().
   Note that escaped chars are stored as
   <NAME_ESCAPE> <orig-char+1>
   to ensure that the escaped form of /000 doesn't include /000
*/
#define NAME_ESCAPE 1