1/*	$OpenBSD: res_mkquery.c,v 1.14 2021/11/22 20:18:27 jca Exp $	*/
2/*
3 * Copyright (c) 2012 Eric Faurot <eric@openbsd.org>
4 *
5 * Permission to use, copy, modify, and distribute this software for any
6 * purpose with or without fee is hereby granted, provided that the above
7 * copyright notice and this permission notice appear in all copies.
8 *
9 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
10 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
11 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
12 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
13 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
14 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
15 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
16 */
17
18#include <sys/types.h>
19#include <sys/socket.h>
20#include <netinet/in.h>
21#include <arpa/nameser.h> /* for MAXDNAME */
22#include <netdb.h>
23
24#include <asr.h>
25#include <errno.h>
26#include <resolv.h>
27#include <string.h>
28
29#include "asr_private.h"
30
31/* This function is apparently needed by some ports. */
32int
33res_mkquery(int op, const char *dname, int class, int type,
34    const unsigned char *data, int datalen, const unsigned char *newrr,
35    unsigned char *buf, int buflen)
36{
37	struct asr_ctx		*ac;
38	struct asr_pack		 p;
39	struct asr_dns_header	 h;
40	char			 fqdn[MAXDNAME];
41	char			 dn[MAXDNAME];
42
43	/* we currently only support QUERY */
44	if (op != QUERY || data)
45		return (-1);
46
47	if (dname[0] == '\0' || dname[strlen(dname) - 1] != '.') {
48		if (strlcpy(fqdn, dname, sizeof(fqdn)) >= sizeof(fqdn) ||
49		    strlcat(fqdn, ".", sizeof(fqdn)) >= sizeof(fqdn))
50			return (-1);
51		dname = fqdn;
52	}
53
54	if (_asr_dname_from_fqdn(dname, dn, sizeof(dn)) == -1)
55		return (-1);
56
57	ac = _asr_use_resolver(NULL);
58
59	memset(&h, 0, sizeof h);
60	h.id = res_randomid();
61	if (ac->ac_options & RES_RECURSE)
62		h.flags |= RD_MASK;
63	if (ac->ac_options & RES_USE_CD)
64		h.flags |= CD_MASK;
65	if (ac->ac_options & RES_TRUSTAD)
66		h.flags |= AD_MASK;
67	h.qdcount = 1;
68	if (ac->ac_options & (RES_USE_EDNS0 | RES_USE_DNSSEC))
69		h.arcount = 1;
70
71	_asr_pack_init(&p, buf, buflen);
72	_asr_pack_header(&p, &h);
73	_asr_pack_query(&p, type, class, dn);
74	if (ac->ac_options & (RES_USE_EDNS0 | RES_USE_DNSSEC))
75		_asr_pack_edns0(&p, MAXPACKETSZ,
76		    ac->ac_options & RES_USE_DNSSEC);
77
78	_asr_ctx_unref(ac);
79
80	if (p.err)
81		return (-1);
82
83	return (p.offset);
84}
85
86/*
87 * This function is not documented, but used by sendmail.
88 * Put here because it uses asr_private.h too.
89 */
90int
91res_querydomain(const char *name,
92    const char *domain,
93    int class,
94    int type,
95    u_char *answer,
96    int anslen)
97{
98	char	fqdn[MAXDNAME], ndom[MAXDNAME];
99	size_t	n;
100
101	/* we really want domain to end with a dot for now */
102	if (domain && ((n = strlen(domain)) == 0 || domain[n - 1 ] != '.')) {
103		if (strlcpy(ndom, domain, sizeof(ndom)) >= sizeof(ndom) ||
104		    strlcat(ndom, ".", sizeof(ndom)) >= sizeof(ndom)) {
105			h_errno = NETDB_INTERNAL;
106			errno = EINVAL;
107			return (-1);
108		}
109		domain = ndom;
110	}
111
112	if (_asr_make_fqdn(name, domain, fqdn, sizeof fqdn) == 0) {
113		h_errno = NETDB_INTERNAL;
114		errno = EINVAL;
115		return (-1);
116	}
117
118	return (res_query(fqdn, class, type, answer, anslen));
119}
120