1 /*	$OpenBSD: unpack_dns.h,v 1.1 2018/01/06 07:57:53 sunil Exp $	*/
2 
3 /*
4  * Copyright (c) 2011-2014 Eric Faurot <eric@faurot.net>
5  *
6  * Permission to use, copy, modify, and distribute this software for any
7  * purpose with or without fee is hereby granted, provided that the above
8  * copyright notice and this permission notice appear in all copies.
9  *
10  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
11  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
12  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
13  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
14  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
15  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
16  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
17  */
18 
19 #include <sys/types.h>
20 
21 #include <netinet/in.h>
22 
23 #include <arpa/inet.h>
24 #include <arpa/nameser.h>
25 
26 struct unpack {
27 	const char	*buf;
28 	size_t		 len;
29 	size_t		 offset;
30 	const char	*err;
31 };
32 
33 struct dns_header {
34 	uint16_t	id;
35 	uint16_t	flags;
36 	uint16_t	qdcount;
37 	uint16_t	ancount;
38 	uint16_t	nscount;
39 	uint16_t	arcount;
40 };
41 
42 struct dns_query {
43 	char		q_dname[MAXDNAME];
44 	uint16_t	q_type;
45 	uint16_t	q_class;
46 };
47 
48 struct dns_rr {
49 	char		rr_dname[MAXDNAME];
50 	uint16_t	rr_type;
51 	uint16_t	rr_class;
52 	uint32_t	rr_ttl;
53 	union {
54 		struct {
55 			char	cname[MAXDNAME];
56 		} cname;
57 		struct {
58 			uint16_t	preference;
59 			char		exchange[MAXDNAME];
60 		} mx;
61 		struct {
62 			char	nsname[MAXDNAME];
63 		} ns;
64 		struct {
65 			char	ptrname[MAXDNAME];
66 		} ptr;
67 		struct {
68 			char		mname[MAXDNAME];
69 			char		rname[MAXDNAME];
70 			uint32_t	serial;
71 			uint32_t	refresh;
72 			uint32_t	retry;
73 			uint32_t	expire;
74 			uint32_t	minimum;
75 		} soa;
76 		struct {
77 			struct in_addr	addr;
78 		} in_a;
79 		struct {
80 			struct in6_addr	addr6;
81 		} in_aaaa;
82 		struct {
83 			uint16_t	 rdlen;
84 			const void	*rdata;
85 		} other;
86 	} rr;
87 };
88 
89 void	 unpack_init(struct unpack *, const char *, size_t);
90 int	 unpack_header(struct unpack *, struct dns_header *);
91 int	 unpack_rr(struct unpack *, struct dns_rr *);
92 int	 unpack_query(struct unpack *, struct dns_query *);
93 char    *print_dname(const char *, char *, size_t);
94 ssize_t	 dname_expand(const unsigned char *, size_t, size_t, size_t *,
95 	    char *, size_t);
96