aboutsummaryrefslogtreecommitdiffstats
path: root/lib/libc/net/getnetbydns.c
blob: e1a11d2e5d3acc0157b718c26ca48cd4a23eb8a4 (plain) (blame)
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
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
/*-
 * Copyright (c) 1985, 1988, 1993
 *	The Regents of the University of California.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *	This product includes software developed by the University of
 *	California, Berkeley and its contributors.
 * 4. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 * -
 * Portions Copyright (c) 1993 by Digital Equipment Corporation.
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies, and that
 * the name of Digital Equipment Corporation not be used in advertising or
 * publicity pertaining to distribution of the document or software without
 * specific, written prior permission.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND DIGITAL EQUIPMENT CORP. DISCLAIMS ALL
 * WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS.   IN NO EVENT SHALL DIGITAL EQUIPMENT
 * CORPORATION BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
 * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
 * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
 * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
 * SOFTWARE.
 * -
 * --Copyright--
 */
/* Portions Copyright (c) 1993 Carlos Leandro and Rui Salgueiro
 *	Dep. Matematica Universidade de Coimbra, Portugal, Europe
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 */

#if defined(LIBC_SCCS) && !defined(lint)
static char sccsid[] = "@(#)gethostnamadr.c	8.1 (Berkeley) 6/4/93";
static char rcsid[] = "$FreeBSD$";
#endif /* LIBC_SCCS and not lint */

#include <sys/param.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <arpa/nameser.h>

#include <stdio.h>
#include <netdb.h>
#include <resolv.h>
#include <ctype.h>
#include <string.h>
#include <unistd.h>
#include <syslog.h>

#include "res_config.h"

extern int h_errno;

#define BYADDR 0
#define BYNAME 1
#define	MAXALIASES	35

#if PACKETSZ > 1024
#define	MAXPACKET	PACKETSZ
#else
#define	MAXPACKET	1024
#endif

typedef union {
	HEADER	hdr;
	u_char	buf[MAXPACKET];
} querybuf;

typedef union {
	long	al;
	char	ac;
} align;

static struct netent *
getnetanswer(answer, anslen, net_i)
	querybuf *answer;
	int anslen;
	int net_i;
{

	register HEADER *hp;
	register u_char *cp;
	register int n;
	u_char *eom;
	int type, class, buflen, ancount, qdcount, haveanswer, i, nchar;
	char aux1[MAXHOSTNAMELEN], aux2[MAXHOSTNAMELEN], ans[MAXHOSTNAMELEN];
	char *in, *st, *pauxt, *bp, **ap;
	char *paux1 = &aux1[0], *paux2 = &aux2[0], flag = 0;
static	struct netent net_entry;
static	char *net_aliases[MAXALIASES], netbuf[PACKETSZ];

	/*
	 * find first satisfactory answer
	 *
	 *      answer --> +------------+  ( MESSAGE )
	 *		   |   Header   |
	 *		   +------------+
	 *		   |  Question  | the question for the name server
	 *		   +------------+
	 *		   |   Answer   | RRs answering the question
	 *		   +------------+
	 *		   | Authority  | RRs pointing toward an authority
	 *		   | Additional | RRs holding additional information
	 *		   +------------+
	 */
	eom = answer->buf + anslen;
	hp = &answer->hdr;
	ancount = ntohs(hp->ancount); /* #/records in the answer section */
	qdcount = ntohs(hp->qdcount); /* #/entries in the question section */
	bp = netbuf;
	buflen = sizeof(netbuf);
	cp = answer->buf + HFIXEDSZ;
	if (!qdcount) {
		if (hp->aa)
			h_errno = HOST_NOT_FOUND;
		else
			h_errno = TRY_AGAIN;
		return (NULL);
	}
	while (qdcount-- > 0)
		cp += __dn_skipname(cp, eom) + QFIXEDSZ;
	ap = net_aliases;
	*ap = NULL;
	net_entry.n_aliases = net_aliases;
	haveanswer = 0;
	while (--ancount >= 0 && cp < eom) {
		n = dn_expand(answer->buf, eom, cp, bp, buflen);
		if ((n < 0) || !res_dnok(bp))
			break;
		cp += n;
		ans[0] = '\0';
		(void)strncpy(&ans[0], bp, sizeof(ans) - 1);
		ans[sizeof(ans) - 1] = '\0';
		GETSHORT(type, cp);
		GETSHORT(class, cp);
		cp += INT32SZ;		/* TTL */
		GETSHORT(n, cp);
		if (class == C_IN && type == T_PTR) {
			n = dn_expand(answer->buf, eom, cp, bp, buflen);
			if ((n < 0) || !res_hnok(bp)) {
				cp += n;
				return (NULL);
			}
			cp += n; 
			*ap++ = bp;
			n = strlen(bp) + 1;
			bp += n;
			buflen -= n;
			net_entry.n_addrtype =
				(class == C_IN) ? AF_INET : AF_UNSPEC;
			haveanswer++;
		}
	}
	if (haveanswer) {
		*ap = NULL;
		switch (net_i) {
		case BYADDR:
			net_entry.n_name = *net_entry.n_aliases;
			net_entry.n_net = 0L;
			break;
		case BYNAME:
			in = *net_entry.n_aliases;
			net_entry.n_name = &ans[0];
			aux2[0] = '\0';
			for (i = 0; i < 4; i++) {
				for (st = in, nchar = 0;
				     *st != '.';
				     st++, nchar++)
					;
				if (nchar != 1 || *in != '0' || flag) {
					flag = 1;
					(void)strncpy(paux1,
						      (i==0) ? in : in-1,
						      (i==0) ?nchar : nchar+1);
					paux1[(i==0) ? nchar : nchar+1] = '\0';
					pauxt = paux2;
					paux2 = strcat(paux1, paux2);
					paux1 = pauxt;
				}
				in = ++st;
			}		  
			net_entry.n_net = inet_network(paux2);
			break;
		}
		net_entry.n_aliases++;
		return (&net_entry);
	}
	h_errno = TRY_AGAIN;
	return (NULL);
}

struct netent *
_getnetbydnsaddr(net, net_type)
	register unsigned long net;
	register int net_type;
{
	unsigned int netbr[4];
	int nn, anslen;
	querybuf buf;
	char qbuf[MAXDNAME];
	unsigned long net2;
	struct netent *net_entry;

	if (net_type != AF_INET)
		return (NULL);

	for (nn = 4, net2 = net; net2; net2 >>= 8)
		netbr[--nn] = net2 & 0xff;
	switch (nn) {
	case 3: 	/* Class A */
		sprintf(qbuf, "0.0.0.%u.in-addr.arpa", netbr[3]);
		break;
	case 2: 	/* Class B */
		sprintf(qbuf, "0.0.%u.%u.in-addr.arpa", netbr[3], netbr[2]);
		break;
	case 1: 	/* Class C */
		sprintf(qbuf, "0.%u.%u.%u.in-addr.arpa", netbr[3], netbr[2],
		    netbr[1]);
		break;
	case 0: 	/* Class D - E */
		sprintf(qbuf, "%u.%u.%u.%u.in-addr.arpa", netbr[3], netbr[2],
		    netbr[1], netbr[0]);
		break;
	}
	anslen = res_query(qbuf, C_IN, T_PTR, (u_char *)&buf, sizeof(buf));
	if (anslen < 0) {
#ifdef DEBUG
		if (_res.options & RES_DEBUG)
			printf("res_query failed\n");
#endif
		return (NULL);
	}
	net_entry = getnetanswer(&buf, anslen, BYADDR);
	if (net_entry) {
		unsigned u_net = net;	/* maybe net should be unsigned ? */

		/* Strip trailing zeros */
		while ((u_net & 0xff) == 0 && u_net != 0)
			u_net >>= 8;
		net_entry->n_net = u_net;
		return (net_entry);
	}
	return (NULL);
}

struct netent *
_getnetbydnsname(net)
	register const char *net;
{
	int anslen;
	querybuf buf;
	char qbuf[MAXDNAME];

	if ((_res.options & RES_INIT) == 0 && res_init() == -1) {
		h_errno = NETDB_INTERNAL;
		return (NULL);
	}
	strncpy(qbuf, net, sizeof(qbuf) - 1);
	qbuf[sizeof(qbuf) - 1] = '\0';
	anslen = res_search(qbuf, C_IN, T_PTR, (u_char *)&buf, sizeof(buf));
	if (anslen < 0) {
#ifdef DEBUG
		if (_res.options & RES_DEBUG)
			printf("res_query failed\n");
#endif
		return (NULL);
	}
	return getnetanswer(&buf, anslen, BYNAME);
}

void
_setnetdnsent(stayopen)
	int stayopen;
{
	if (stayopen)
		_res.options |= RES_STAYOPEN | RES_USEVC;
}

void
_endnetdnsent()
{
	_res.options &= ~(RES_STAYOPEN | RES_USEVC);
	res_close();
}