1 /*-
2 * Copyright (c) 1985, 1988, 1993
3 * The Regents of the University of California. All rights reserved.
4 *
5 * %sccs.include.redist.c%
6 * -
7 * Portions Copyright (c) 1993 by Digital Equipment Corporation.
8 *
9 * Permission to use, copy, modify, and distribute this software for any
10 * purpose with or without fee is hereby granted, provided that the above
11 * copyright notice and this permission notice appear in all copies, and that
12 * the name of Digital Equipment Corporation not be used in advertising or
13 * publicity pertaining to distribution of the document or software without
14 * specific, written prior permission.
15 *
16 * THE SOFTWARE IS PROVIDED "AS IS" AND DIGITAL EQUIPMENT CORP. DISCLAIMS ALL
17 * WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES
18 * OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL DIGITAL EQUIPMENT
19 * CORPORATION BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
20 * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
21 * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
22 * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
23 * SOFTWARE.
24 * -
25 * --Copyright--
26 */
27
28 #if defined(LIBC_SCCS) && !defined(lint)
29 static char sccsid[] = "@(#)gethostnamadr.c 8.1 (Berkeley) 06/04/93";
30 static char rcsid[] = "$Id: gethnamaddr.c,v 4.9.1.1 1993/05/02 22:43:03 vixie Rel $";
31 #endif /* LIBC_SCCS and not lint */
32
33 #include <sys/param.h>
34 #include <sys/socket.h>
35 #include <netinet/in.h>
36 #include <arpa/inet.h>
37 #include <arpa/nameser.h>
38 #include <netdb.h>
39 #include <resolv.h>
40 #include <stdio.h>
41 #include <ctype.h>
42 #include <errno.h>
43 #include <string.h>
44
45 #define MAXALIASES 35
46 #define MAXADDRS 35
47
48 static char *h_addr_ptrs[MAXADDRS + 1];
49
50 static struct hostent host;
51 static char *host_aliases[MAXALIASES];
52 static char hostbuf[BUFSIZ+1];
53 static struct in_addr host_addr;
54 static FILE *hostf = NULL;
55 static char hostaddr[MAXADDRS];
56 static char *host_addrs[2];
57 static int stayopen = 0;
58 char *strpbrk();
59
60 #if PACKETSZ > 1024
61 #define MAXPACKET PACKETSZ
62 #else
63 #define MAXPACKET 1024
64 #endif
65
66 typedef union {
67 HEADER hdr;
68 u_char buf[MAXPACKET];
69 } querybuf;
70
71 typedef union {
72 int32_t al;
73 char ac;
74 } align;
75
76 extern int h_errno;
77
78 static struct hostent *
getanswer(answer,anslen,iquery)79 getanswer(answer, anslen, iquery)
80 querybuf *answer;
81 int anslen;
82 int iquery;
83 {
84 register HEADER *hp;
85 register u_char *cp;
86 register int n;
87 u_char *eom;
88 char *bp, **ap;
89 int type, class, buflen, ancount, qdcount;
90 int haveanswer, getclass = C_ANY;
91 char **hap;
92
93 eom = answer->buf + anslen;
94 /*
95 * find first satisfactory answer
96 */
97 hp = &answer->hdr;
98 ancount = ntohs(hp->ancount);
99 qdcount = ntohs(hp->qdcount);
100 bp = hostbuf;
101 buflen = sizeof(hostbuf);
102 cp = answer->buf + sizeof(HEADER);
103 if (qdcount) {
104 if (iquery) {
105 if ((n = dn_expand((u_char *)answer->buf,
106 (u_char *)eom, (u_char *)cp, (u_char *)bp,
107 buflen)) < 0) {
108 h_errno = NO_RECOVERY;
109 return ((struct hostent *) NULL);
110 }
111 cp += n + QFIXEDSZ;
112 host.h_name = bp;
113 n = strlen(bp) + 1;
114 bp += n;
115 buflen -= n;
116 } else
117 cp += __dn_skipname(cp, eom) + QFIXEDSZ;
118 while (--qdcount > 0)
119 cp += __dn_skipname(cp, eom) + QFIXEDSZ;
120 } else if (iquery) {
121 if (hp->aa)
122 h_errno = HOST_NOT_FOUND;
123 else
124 h_errno = TRY_AGAIN;
125 return ((struct hostent *) NULL);
126 }
127 ap = host_aliases;
128 *ap = NULL;
129 host.h_aliases = host_aliases;
130 hap = h_addr_ptrs;
131 *hap = NULL;
132 #if BSD >= 43 || defined(h_addr) /* new-style hostent structure */
133 host.h_addr_list = h_addr_ptrs;
134 #endif
135 haveanswer = 0;
136 while (--ancount >= 0 && cp < eom) {
137 if ((n = dn_expand((u_char *)answer->buf, (u_char *)eom,
138 (u_char *)cp, (u_char *)bp, buflen)) < 0)
139 break;
140 cp += n;
141 type = _getshort(cp);
142 cp += sizeof(u_int16_t);
143 class = _getshort(cp);
144 cp += sizeof(u_int16_t) + sizeof(u_int32_t);
145 n = _getshort(cp);
146 cp += sizeof(u_int16_t);
147 if (type == T_CNAME) {
148 cp += n;
149 if (ap >= &host_aliases[MAXALIASES-1])
150 continue;
151 *ap++ = bp;
152 n = strlen(bp) + 1;
153 bp += n;
154 buflen -= n;
155 continue;
156 }
157 if (iquery && type == T_PTR) {
158 if ((n = dn_expand((u_char *)answer->buf,
159 (u_char *)eom, (u_char *)cp, (u_char *)bp,
160 buflen)) < 0)
161 break;
162 cp += n;
163 host.h_name = bp;
164 return(&host);
165 }
166 if (iquery || type != T_A) {
167 #ifdef DEBUG
168 if (_res.options & RES_DEBUG)
169 printf("unexpected answer type %d, size %d\n",
170 type, n);
171 #endif
172 cp += n;
173 continue;
174 }
175 if (haveanswer) {
176 if (n != host.h_length) {
177 cp += n;
178 continue;
179 }
180 if (class != getclass) {
181 cp += n;
182 continue;
183 }
184 } else {
185 host.h_length = n;
186 getclass = class;
187 host.h_addrtype = (class == C_IN) ? AF_INET : AF_UNSPEC;
188 if (!iquery) {
189 host.h_name = bp;
190 bp += strlen(bp) + 1;
191 }
192 }
193
194 bp += sizeof(align) - ((u_int32_t)bp % sizeof(align));
195
196 if (bp + n >= &hostbuf[sizeof(hostbuf)]) {
197 #ifdef DEBUG
198 if (_res.options & RES_DEBUG)
199 printf("size (%d) too big\n", n);
200 #endif
201 break;
202 }
203 bcopy(cp, *hap++ = bp, n);
204 bp +=n;
205 cp += n;
206 haveanswer++;
207 }
208 if (haveanswer) {
209 *ap = NULL;
210 #if BSD >= 43 || defined(h_addr) /* new-style hostent structure */
211 *hap = NULL;
212 #else
213 host.h_addr = h_addr_ptrs[0];
214 #endif
215 return (&host);
216 } else {
217 h_errno = TRY_AGAIN;
218 return ((struct hostent *) NULL);
219 }
220 }
221
222 struct hostent *
gethostbyname(name)223 gethostbyname(name)
224 const char *name;
225 {
226 querybuf buf;
227 register const char *cp;
228 int n;
229 extern struct hostent *_gethtbyname();
230
231 /*
232 * disallow names consisting only of digits/dots, unless
233 * they end in a dot.
234 */
235 if (isdigit(name[0]))
236 for (cp = name;; ++cp) {
237 if (!*cp) {
238 if (*--cp == '.')
239 break;
240 /*
241 * All-numeric, no dot at the end.
242 * Fake up a hostent as if we'd actually
243 * done a lookup.
244 */
245 if (!inet_aton(name, &host_addr)) {
246 h_errno = HOST_NOT_FOUND;
247 return((struct hostent *) NULL);
248 }
249 host.h_name = (char *)name;
250 host.h_aliases = host_aliases;
251 host_aliases[0] = NULL;
252 host.h_addrtype = AF_INET;
253 host.h_length = sizeof(u_int32_t);
254 h_addr_ptrs[0] = (char *)&host_addr;
255 h_addr_ptrs[1] = (char *)0;
256 #if BSD >= 43 || defined(h_addr) /* new-style hostent structure */
257 host.h_addr_list = h_addr_ptrs;
258 #else
259 host.h_addr = h_addr_ptrs[0];
260 #endif
261 return (&host);
262 }
263 if (!isdigit(*cp) && *cp != '.')
264 break;
265 }
266
267 if ((n = res_search(name, C_IN, T_A, buf.buf, sizeof(buf))) < 0) {
268 #ifdef DEBUG
269 if (_res.options & RES_DEBUG)
270 printf("res_search failed\n");
271 #endif
272 if (errno == ECONNREFUSED)
273 return (_gethtbyname(name));
274 else
275 return ((struct hostent *) NULL);
276 }
277 return (getanswer(&buf, n, 0));
278 }
279
280 struct hostent *
gethostbyaddr(addr,len,type)281 gethostbyaddr(addr, len, type)
282 const char *addr;
283 int len, type;
284 {
285 int n;
286 querybuf buf;
287 register struct hostent *hp;
288 char qbuf[MAXDNAME];
289 extern struct hostent *_gethtbyaddr();
290
291 if (type != AF_INET)
292 return ((struct hostent *) NULL);
293 (void)sprintf(qbuf, "%u.%u.%u.%u.in-addr.arpa",
294 ((unsigned)addr[3] & 0xff),
295 ((unsigned)addr[2] & 0xff),
296 ((unsigned)addr[1] & 0xff),
297 ((unsigned)addr[0] & 0xff));
298 n = res_query(qbuf, C_IN, T_PTR, (char *)&buf, sizeof(buf));
299 if (n < 0) {
300 #ifdef DEBUG
301 if (_res.options & RES_DEBUG)
302 printf("res_query failed\n");
303 #endif
304 if (errno == ECONNREFUSED)
305 return (_gethtbyaddr(addr, len, type));
306 return ((struct hostent *) NULL);
307 }
308 hp = getanswer(&buf, n, 1);
309 if (hp == NULL)
310 return ((struct hostent *) NULL);
311 hp->h_addrtype = type;
312 hp->h_length = len;
313 h_addr_ptrs[0] = (char *)&host_addr;
314 h_addr_ptrs[1] = (char *)0;
315 host_addr = *(struct in_addr *)addr;
316 #if BSD < 43 && !defined(h_addr) /* new-style hostent structure */
317 hp->h_addr = h_addr_ptrs[0];
318 #endif
319 return(hp);
320 }
321
322 void
_sethtent(f)323 _sethtent(f)
324 int f;
325 {
326 if (hostf == NULL)
327 hostf = fopen(_PATH_HOSTS, "r" );
328 else
329 rewind(hostf);
330 stayopen |= f;
331 }
332
333 void
_endhtent()334 _endhtent()
335 {
336 if (hostf && !stayopen) {
337 (void) fclose(hostf);
338 hostf = NULL;
339 }
340 }
341
342 struct hostent *
_gethtent()343 _gethtent()
344 {
345 char *p;
346 register char *cp, **q;
347
348 if (hostf == NULL && (hostf = fopen(_PATH_HOSTS, "r" )) == NULL)
349 return (NULL);
350 again:
351 if ((p = fgets(hostbuf, BUFSIZ, hostf)) == NULL)
352 return (NULL);
353 if (*p == '#')
354 goto again;
355 cp = strpbrk(p, "#\n");
356 if (cp == NULL)
357 goto again;
358 *cp = '\0';
359 cp = strpbrk(p, " \t");
360 if (cp == NULL)
361 goto again;
362 *cp++ = '\0';
363 /* THIS STUFF IS INTERNET SPECIFIC */
364 #if BSD >= 43 || defined(h_addr) /* new-style hostent structure */
365 host.h_addr_list = host_addrs;
366 #endif
367 host.h_addr = hostaddr;
368 *((u_int32_t *)host.h_addr) = inet_addr(p);
369 host.h_length = sizeof (u_int32_t);
370 host.h_addrtype = AF_INET;
371 while (*cp == ' ' || *cp == '\t')
372 cp++;
373 host.h_name = cp;
374 q = host.h_aliases = host_aliases;
375 cp = strpbrk(cp, " \t");
376 if (cp != NULL)
377 *cp++ = '\0';
378 while (cp && *cp) {
379 if (*cp == ' ' || *cp == '\t') {
380 cp++;
381 continue;
382 }
383 if (q < &host_aliases[MAXALIASES - 1])
384 *q++ = cp;
385 cp = strpbrk(cp, " \t");
386 if (cp != NULL)
387 *cp++ = '\0';
388 }
389 *q = NULL;
390 return (&host);
391 }
392
393 struct hostent *
_gethtbyname(name)394 _gethtbyname(name)
395 char *name;
396 {
397 register struct hostent *p;
398 register char **cp;
399
400 _sethtent(0);
401 while (p = _gethtent()) {
402 if (strcasecmp(p->h_name, name) == 0)
403 break;
404 for (cp = p->h_aliases; *cp != 0; cp++)
405 if (strcasecmp(*cp, name) == 0)
406 goto found;
407 }
408 found:
409 _endhtent();
410 return (p);
411 }
412
413 struct hostent *
_gethtbyaddr(addr,len,type)414 _gethtbyaddr(addr, len, type)
415 const char *addr;
416 int len, type;
417 {
418 register struct hostent *p;
419
420 _sethtent(0);
421 while (p = _gethtent())
422 if (p->h_addrtype == type && !bcmp(p->h_addr, addr, len))
423 break;
424 _endhtent();
425 return (p);
426 }
427