source: rtems/cpukit/libnetworking/libc/getnetbydns.c @ 9d647dfc

4.104.114.84.95
Last change on this file since 9d647dfc was 39e6e65a, checked in by Joel Sherrill <joel.sherrill@…>, on 08/19/98 at 21:32:28

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1/*-
2 * Copyright (c) 1985, 1988, 1993
3 *      The Regents of the University of California.  All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 *    notice, this list of conditions and the following disclaimer in the
12 *    documentation and/or other materials provided with the distribution.
13 * 3. All advertising materials mentioning features or use of this software
14 *    must display the following acknowledgement:
15 *      This product includes software developed by the University of
16 *      California, Berkeley and its contributors.
17 * 4. Neither the name of the University nor the names of its contributors
18 *    may be used to endorse or promote products derived from this software
19 *    without specific prior written permission.
20 *
21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31 * SUCH DAMAGE.
32 * -
33 * Portions Copyright (c) 1993 by Digital Equipment Corporation.
34 *
35 * Permission to use, copy, modify, and distribute this software for any
36 * purpose with or without fee is hereby granted, provided that the above
37 * copyright notice and this permission notice appear in all copies, and that
38 * the name of Digital Equipment Corporation not be used in advertising or
39 * publicity pertaining to distribution of the document or software without
40 * specific, written prior permission.
41 *
42 * THE SOFTWARE IS PROVIDED "AS IS" AND DIGITAL EQUIPMENT CORP. DISCLAIMS ALL
43 * WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES
44 * OF MERCHANTABILITY AND FITNESS.   IN NO EVENT SHALL DIGITAL EQUIPMENT
45 * CORPORATION BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
46 * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
47 * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
48 * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
49 * SOFTWARE.
50 * -
51 * --Copyright--
52 */
53/* Portions Copyright (c) 1993 Carlos Leandro and Rui Salgueiro
54 *      Dep. Matematica Universidade de Coimbra, Portugal, Europe
55 *
56 * Permission to use, copy, modify, and distribute this software for any
57 * purpose with or without fee is hereby granted, provided that the above
58 * copyright notice and this permission notice appear in all copies.
59 */
60
61#if defined(LIBC_SCCS) && !defined(lint)
62static char sccsid[] = "@(#)gethostnamadr.c     8.1 (Berkeley) 6/4/93";
63static char rcsid[] = "$Id$";
64#endif /* LIBC_SCCS and not lint */
65
66#include <sys/param.h>
67#include <sys/socket.h>
68#include <netinet/in.h>
69#include <arpa/inet.h>
70#include <arpa/nameser.h>
71
72#include <stdio.h>
73#include <netdb.h>
74#include <resolv.h>
75#include <ctype.h>
76#include <errno.h>
77#include <string.h>
78#include <unistd.h>
79#include <syslog.h>
80
81#include "res_config.h"
82
83extern int h_errno;
84
85#define BYADDR 0
86#define BYNAME 1
87#define MAXALIASES      35
88
89#if PACKETSZ > 1024
90#define MAXPACKET       PACKETSZ
91#else
92#define MAXPACKET       1024
93#endif
94
95typedef union {
96        HEADER  hdr;
97        u_char  buf[MAXPACKET];
98} querybuf;
99
100typedef union {
101        long    al;
102        char    ac;
103} align;
104
105static struct netent *
106getnetanswer(answer, anslen, net_i)
107        querybuf *answer;
108        int anslen;
109        int net_i;
110{
111
112        register HEADER *hp;
113        register u_char *cp;
114        register int n;
115        u_char *eom;
116        int type, class, buflen, ancount, qdcount, haveanswer, i, nchar;
117        char aux1[MAXHOSTNAMELEN], aux2[MAXHOSTNAMELEN], ans[MAXHOSTNAMELEN];
118        char *in, *st, *pauxt, *bp, **ap;
119        char *paux1 = &aux1[0], *paux2 = &aux2[0], flag = 0;
120static  struct netent net_entry;
121static  char *net_aliases[MAXALIASES], netbuf[PACKETSZ];
122
123        /*
124         * find first satisfactory answer
125         *
126         *      answer --> +------------+  ( MESSAGE )
127         *                 |   Header   |
128         *                 +------------+
129         *                 |  Question  | the question for the name server
130         *                 +------------+
131         *                 |   Answer   | RRs answering the question
132         *                 +------------+
133         *                 | Authority  | RRs pointing toward an authority
134         *                 | Additional | RRs holding additional information
135         *                 +------------+
136         */
137        eom = answer->buf + anslen;
138        hp = &answer->hdr;
139        ancount = ntohs(hp->ancount); /* #/records in the answer section */
140        qdcount = ntohs(hp->qdcount); /* #/entries in the question section */
141        bp = netbuf;
142        buflen = sizeof(netbuf);
143        cp = answer->buf + HFIXEDSZ;
144        if (!qdcount) {
145                if (hp->aa)
146                        h_errno = HOST_NOT_FOUND;
147                else
148                        h_errno = TRY_AGAIN;
149                return (NULL);
150        }
151        while (qdcount-- > 0)
152                cp += __dn_skipname(cp, eom) + QFIXEDSZ;
153        ap = net_aliases;
154        *ap = NULL;
155        net_entry.n_aliases = net_aliases;
156        haveanswer = 0;
157        while (--ancount >= 0 && cp < eom) {
158                n = dn_expand(answer->buf, eom, cp, bp, buflen);
159                if ((n < 0) || !res_dnok(bp))
160                        break;
161                cp += n;
162                ans[0] = '\0';
163                (void)strncpy(&ans[0], bp, sizeof(ans) - 1);
164                ans[sizeof(ans) - 1] = '\0';
165                GETSHORT(type, cp);
166                GETSHORT(class, cp);
167                cp += INT32SZ;          /* TTL */
168                GETSHORT(n, cp);
169                if (class == C_IN && type == T_PTR) {
170                        n = dn_expand(answer->buf, eom, cp, bp, buflen);
171                        if ((n < 0) || !res_hnok(bp)) {
172                                cp += n;
173                                return (NULL);
174                        }
175                        cp += n;
176                        *ap++ = bp;
177                        bp += strlen(bp) + 1;
178                        net_entry.n_addrtype =
179                                (class == C_IN) ? AF_INET : AF_UNSPEC;
180                        haveanswer++;
181                }
182        }
183        if (haveanswer) {
184                *ap = NULL;
185                switch (net_i) {
186                case BYADDR:
187                        net_entry.n_name = *net_entry.n_aliases;
188                        net_entry.n_net = 0L;
189                        break;
190                case BYNAME:
191                        in = *net_entry.n_aliases;
192                        net_entry.n_name = &ans[0];
193                        aux2[0] = '\0';
194                        for (i = 0; i < 4; i++) {
195                                for (st = in, nchar = 0;
196                                     *st != '.';
197                                     st++, nchar++)
198                                        ;
199                                if (nchar != 1 || *in != '0' || flag) {
200                                        flag = 1;
201                                        (void)strncpy(paux1,
202                                                      (i==0) ? in : in-1,
203                                                      (i==0) ?nchar : nchar+1);
204                                        paux1[(i==0) ? nchar : nchar+1] = '\0';
205                                        pauxt = paux2;
206                                        paux2 = strcat(paux1, paux2);
207                                        paux1 = pauxt;
208                                }
209                                in = ++st;
210                        }                 
211                        net_entry.n_net = inet_network(paux2);
212                        break;
213                }
214                net_entry.n_aliases++;
215                return (&net_entry);
216        }
217        h_errno = TRY_AGAIN;
218        return (NULL);
219}
220
221struct netent *
222_getnetbydnsaddr(net, net_type)
223        register unsigned long net;
224        register int net_type;
225{
226        unsigned int netbr[4];
227        int nn, anslen;
228        querybuf buf;
229        char qbuf[MAXDNAME];
230        unsigned long net2;
231        struct netent *net_entry;
232
233        if (net_type != AF_INET)
234                return (NULL);
235
236        for (nn = 4, net2 = net; net2; net2 >>= 8)
237                netbr[--nn] = net2 & 0xff;
238        switch (nn) {
239        case 3:         /* Class A */
240                sprintf(qbuf, "0.0.0.%u.in-addr.arpa", netbr[3]);
241                break;
242        case 2:         /* Class B */
243                sprintf(qbuf, "0.0.%u.%u.in-addr.arpa", netbr[3], netbr[2]);
244                break;
245        case 1:         /* Class C */
246                sprintf(qbuf, "0.%u.%u.%u.in-addr.arpa", netbr[3], netbr[2],
247                    netbr[1]);
248                break;
249        case 0:         /* Class D - E */
250                sprintf(qbuf, "%u.%u.%u.%u.in-addr.arpa", netbr[3], netbr[2],
251                    netbr[1], netbr[0]);
252                break;
253        }
254        anslen = res_query(qbuf, C_IN, T_PTR, (u_char *)&buf, sizeof(buf));
255        if (anslen < 0) {
256#ifdef DEBUG
257                if (_res.options & RES_DEBUG)
258                        printf("res_query failed\n");
259#endif
260                return (NULL);
261        }
262        net_entry = getnetanswer(&buf, anslen, BYADDR);
263        if (net_entry) {
264                unsigned u_net = net;   /* maybe net should be unsigned ? */
265
266                /* Strip trailing zeros */
267                while ((u_net & 0xff) == 0 && u_net != 0)
268                        u_net >>= 8;
269                net_entry->n_net = u_net;
270                return (net_entry);
271        }
272        return (NULL);
273}
274
275struct netent *
276_getnetbydnsname(net)
277        register const char *net;
278{
279        int anslen;
280        querybuf buf;
281        char qbuf[MAXDNAME];
282
283        if ((_res.options & RES_INIT) == 0 && res_init() == -1) {
284                h_errno = NETDB_INTERNAL;
285                return (NULL);
286        }
287        strncpy(qbuf, net, sizeof(qbuf) - 1);
288        qbuf[sizeof(qbuf) - 1] = '\0';
289        anslen = res_search(qbuf, C_IN, T_PTR, (u_char *)&buf, sizeof(buf));
290        if (anslen < 0) {
291#ifdef DEBUG
292                if (_res.options & RES_DEBUG)
293                        printf("res_query failed\n");
294#endif
295                return (NULL);
296        }
297        return getnetanswer(&buf, anslen, BYNAME);
298}
299
300void
301_setnetdnsent(stayopen)
302        int stayopen;
303{
304        if (stayopen)
305                _res.options |= RES_STAYOPEN | RES_USEVC;
306}
307
308void
309_endnetdnsent()
310{
311        _res.options &= ~(RES_STAYOPEN | RES_USEVC);
312        res_close();
313}
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