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[/] [openrisc/] [trunk/] [rtos/] [rtems/] [c/] [src/] [libnetworking/] [libc/] [res_send.c] - Blame information for rev 30

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/*
2
 * Copyright (c) 1985, 1989, 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
 
34
/*
35
 * Portions Copyright (c) 1993 by Digital Equipment Corporation.
36
 *
37
 * Permission to use, copy, modify, and distribute this software for any
38
 * purpose with or without fee is hereby granted, provided that the above
39
 * copyright notice and this permission notice appear in all copies, and that
40
 * the name of Digital Equipment Corporation not be used in advertising or
41
 * publicity pertaining to distribution of the document or software without
42
 * specific, written prior permission.
43
 *
44
 * THE SOFTWARE IS PROVIDED "AS IS" AND DIGITAL EQUIPMENT CORP. DISCLAIMS ALL
45
 * WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES
46
 * OF MERCHANTABILITY AND FITNESS.   IN NO EVENT SHALL DIGITAL EQUIPMENT
47
 * CORPORATION BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
48
 * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
49
 * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
50
 * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
51
 * SOFTWARE.
52
 */
53
 
54
/*
55
 * Portions Copyright (c) 1996 by Internet Software Consortium.
56
 *
57
 * Permission to use, copy, modify, and distribute this software for any
58
 * purpose with or without fee is hereby granted, provided that the above
59
 * copyright notice and this permission notice appear in all copies.
60
 *
61
 * THE SOFTWARE IS PROVIDED "AS IS" AND INTERNET SOFTWARE CONSORTIUM DISCLAIMS
62
 * ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES
63
 * OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL INTERNET SOFTWARE
64
 * CONSORTIUM BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
65
 * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
66
 * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
67
 * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
68
 * SOFTWARE.
69
 */
70
 
71
#if defined(LIBC_SCCS) && !defined(lint)
72
static char sccsid[] = "@(#)res_send.c  8.1 (Berkeley) 6/4/93";
73
static char orig_rcsid[] = "From: Id: res_send.c,v 8.20 1998/04/06 23:27:51 halley Exp $";
74
static char rcsid[] = "$Id: res_send.c,v 1.2 2001-09-27 12:01:53 chris Exp $";
75
#endif /* LIBC_SCCS and not lint */
76
 
77
/*
78
 * Send query to name server and wait for reply.
79
 */
80
 
81
#include <sys/types.h>
82
#include <sys/param.h>
83
#include <sys/time.h>
84
#include <sys/socket.h>
85
#include <sys/uio.h>
86
 
87
#include <netinet/in.h>
88
#include <arpa/nameser.h>
89
#include <arpa/inet.h>
90
 
91
#include <errno.h>
92
#include <netdb.h>
93
#include <resolv.h>
94
#include <stdio.h>
95
#include <stdlib.h>
96
#include <string.h>
97
#include <unistd.h>
98
#include <poll.h>
99
 
100
#include "res_config.h"
101
 
102
#if !defined(__rtems__)
103
#ifdef NOPOLL                   /* libc_r doesn't wrap poll yet() */
104
static int use_poll = 0;
105
#else
106
static int use_poll = 1;        /* adapt to poll() syscall availability */
107
                                /* 0 = not present, 1 = try it, 2 = exists */
108
#endif
109
#endif
110
 
111
static int s = -1;              /* socket used for communications */
112
static int connected = 0;        /* is the socket connected */
113
static int vc = 0;               /* is the socket a virtual circuit? */
114
static res_send_qhook Qhook = NULL;
115
static res_send_rhook Rhook = NULL;
116
 
117
 
118
#define CAN_RECONNECT 1
119
 
120
#ifndef DEBUG
121
#   define Dprint(cond, args) /*empty*/
122
#   define DprintQ(cond, args, query, size) /*empty*/
123
#   define Aerror(file, string, error, address) /*empty*/
124
#   define Perror(file, string, error) /*empty*/
125
#else
126
#   define Dprint(cond, args) if (cond) {fprintf args;} else {}
127
#   define DprintQ(cond, args, query, size) if (cond) {\
128
                        fprintf args;\
129
                        __fp_nquery(query, size, stdout);\
130
                } else {}
131
    static void
132
    Aerror(file, string, error, address)
133
        FILE *file;
134
        char *string;
135
        int error;
136
        struct sockaddr_in address;
137
    {
138
        int save = errno;
139
 
140
        if (_res.options & RES_DEBUG) {
141
                fprintf(file, "res_send: %s ([%s].%u): %s\n",
142
                        string,
143
                        inet_ntoa(address.sin_addr),
144
                        ntohs(address.sin_port),
145
                        strerror(error));
146
        }
147
        errno = save;
148
    }
149
    static void
150
    Perror(file, string, error)
151
        FILE *file;
152
        char *string;
153
        int error;
154
    {
155
        int save = errno;
156
 
157
        if (_res.options & RES_DEBUG) {
158
                fprintf(file, "res_send: %s: %s\n",
159
                        string, strerror(error));
160
        }
161
        errno = save;
162
    }
163
#endif
164
 
165
void
166
res_send_setqhook(hook)
167
        res_send_qhook hook;
168
{
169
 
170
        Qhook = hook;
171
}
172
 
173
void
174
res_send_setrhook(hook)
175
        res_send_rhook hook;
176
{
177
 
178
        Rhook = hook;
179
}
180
 
181
/* int
182
 * res_isourserver(ina)
183
 *      looks up "ina" in _res.ns_addr_list[]
184
 * returns:
185
 *      0  : not found
186
 *      >0 : found
187
 * author:
188
 *      paul vixie, 29may94
189
 */
190
int
191
res_isourserver(inp)
192
        const struct sockaddr_in *inp;
193
{
194
        struct sockaddr_in ina;
195
        int ns, ret;
196
 
197
        ina = *inp;
198
        ret = 0;
199
        for (ns = 0;  ns < _res.nscount;  ns++) {
200
                const struct sockaddr_in *srv = &_res.nsaddr_list[ns];
201
 
202
                if (srv->sin_family == ina.sin_family &&
203
                    srv->sin_port == ina.sin_port &&
204
                    (srv->sin_addr.s_addr == INADDR_ANY ||
205
                     srv->sin_addr.s_addr == ina.sin_addr.s_addr)) {
206
                        ret++;
207
                        break;
208
                }
209
        }
210
        return (ret);
211
}
212
 
213
/* int
214
 * res_nameinquery(name, type, class, buf, eom)
215
 *      look for (name,type,class) in the query section of packet (buf,eom)
216
 * requires:
217
 *      buf + HFIXEDSZ <= eom
218
 * returns:
219
 *      -1 : format error
220
 *      0  : not found
221
 *      >0 : found
222
 * author:
223
 *      paul vixie, 29may94
224
 */
225
int
226
res_nameinquery(name, type, class, buf, eom)
227
        const char *name;
228
        int type, class;
229
        const u_char *buf, *eom;
230
{
231
        const u_char *cp = buf + HFIXEDSZ;
232
        int qdcount = ntohs(((HEADER*)buf)->qdcount);
233
 
234
        while (qdcount-- > 0) {
235
                char tname[MAXDNAME+1];
236
                int n, ttype, tclass;
237
 
238
                n = dn_expand(buf, eom, cp, tname, sizeof tname);
239
                if (n < 0)
240
                        return (-1);
241
                cp += n;
242
                if (cp + 2 * INT16SZ > eom)
243
                        return (-1);
244
                ttype = ns_get16(cp); cp += INT16SZ;
245
                tclass = ns_get16(cp); cp += INT16SZ;
246
                if (ttype == type &&
247
                    tclass == class &&
248
                    strcasecmp(tname, name) == 0)
249
                        return (1);
250
        }
251
        return (0);
252
}
253
 
254
/* int
255
 * res_queriesmatch(buf1, eom1, buf2, eom2)
256
 *      is there a 1:1 mapping of (name,type,class)
257
 *      in (buf1,eom1) and (buf2,eom2)?
258
 * returns:
259
 *      -1 : format error
260
 *      0  : not a 1:1 mapping
261
 *      >0 : is a 1:1 mapping
262
 * author:
263
 *      paul vixie, 29may94
264
 */
265
int
266
res_queriesmatch(buf1, eom1, buf2, eom2)
267
        const u_char *buf1, *eom1;
268
        const u_char *buf2, *eom2;
269
{
270
        const u_char *cp = buf1 + HFIXEDSZ;
271
        int qdcount = ntohs(((HEADER*)buf1)->qdcount);
272
 
273
        if (buf1 + HFIXEDSZ > eom1 || buf2 + HFIXEDSZ > eom2)
274
                return (-1);
275
 
276
        /*
277
         * Only header section present in replies to
278
         * dynamic update packets.
279
         */
280
        if ( (((HEADER *)buf1)->opcode == ns_o_update) &&
281
             (((HEADER *)buf2)->opcode == ns_o_update) )
282
                return (1);
283
 
284
        if (qdcount != ntohs(((HEADER*)buf2)->qdcount))
285
                return (0);
286
        while (qdcount-- > 0) {
287
                char tname[MAXDNAME+1];
288
                int n, ttype, tclass;
289
 
290
                n = dn_expand(buf1, eom1, cp, tname, sizeof tname);
291
                if (n < 0)
292
                        return (-1);
293
                cp += n;
294
                if (cp + 2 * INT16SZ > eom1)
295
                        return (-1);
296
                ttype = ns_get16(cp);   cp += INT16SZ;
297
                tclass = ns_get16(cp); cp += INT16SZ;
298
                if (!res_nameinquery(tname, ttype, tclass, buf2, eom2))
299
                        return (0);
300
        }
301
        return (1);
302
}
303
 
304
int
305
res_send(buf, buflen, ans, anssiz)
306
        const u_char *buf;
307
        int buflen;
308
        u_char *ans;
309
        int anssiz;
310
{
311
        HEADER *hp = (HEADER *) buf;
312
        HEADER *anhp = (HEADER *) ans;
313
        int gotsomewhere, connreset, terrno, try, v_circuit, resplen, ns, n;
314
        u_int badns;    /* XXX NSMAX can't exceed #/bits in this variable */
315
 
316
        if ((_res.options & RES_INIT) == 0 && res_init() == -1) {
317
                /* errno should have been set by res_init() in this case. */
318
                return (-1);
319
        }
320
        if (anssiz < HFIXEDSZ) {
321
                errno = EINVAL;
322
                return (-1);
323
        }
324
        DprintQ((_res.options & RES_DEBUG) || (_res.pfcode & RES_PRF_QUERY),
325
                (stdout, ";; res_send()\n"), buf, buflen);
326
        v_circuit = (_res.options & RES_USEVC) || buflen > PACKETSZ;
327
        gotsomewhere = 0;
328
        connreset = 0;
329
        terrno = ETIMEDOUT;
330
        badns = 0;
331
 
332
        /*
333
         * Send request, RETRY times, or until successful
334
         */
335
        for (try = 0; try < _res.retry; try++) {
336
            for (ns = 0; ns < _res.nscount; ns++) {
337
                struct sockaddr_in *nsap = &_res.nsaddr_list[ns];
338
    same_ns:
339
                if (badns & (1 << ns)) {
340
                        res_close();
341
                        goto next_ns;
342
                }
343
 
344
                if (Qhook) {
345
                        int done = 0, loops = 0;
346
 
347
                        do {
348
                                res_sendhookact act;
349
 
350
                                act = (*Qhook)(&nsap, &buf, &buflen,
351
                                               ans, anssiz, &resplen);
352
                                switch (act) {
353
                                case res_goahead:
354
                                        done = 1;
355
                                        break;
356
                                case res_nextns:
357
                                        res_close();
358
                                        goto next_ns;
359
                                case res_done:
360
                                        return (resplen);
361
                                case res_modified:
362
                                        /* give the hook another try */
363
                                        if (++loops < 42) /*doug adams*/
364
                                                break;
365
                                        /*FALLTHROUGH*/
366
                                case res_error:
367
                                        /*FALLTHROUGH*/
368
                                default:
369
                                        return (-1);
370
                                }
371
                        } while (!done);
372
                }
373
 
374
                Dprint(_res.options & RES_DEBUG,
375
                       (stdout, ";; Querying server (# %d) address = %s\n",
376
                        ns + 1, inet_ntoa(nsap->sin_addr)));
377
 
378
                if (v_circuit) {
379
                        int truncated;
380
#if !defined(__rtems__)
381
                        struct iovec iov[2];
382
#endif
383
                        u_short len;
384
                        u_char *cp;
385
 
386
                        /*
387
                         * Use virtual circuit;
388
                         * at most one attempt per server.
389
                         */
390
                        try = _res.retry;
391
                        truncated = 0;
392
                        if (s < 0 || !vc || hp->opcode == ns_o_update) {
393
                                if (s >= 0)
394
                                        res_close();
395
 
396
                                s = socket(PF_INET, SOCK_STREAM, 0);
397
                                if (s < 0) {
398
                                        terrno = errno;
399
                                        Perror(stderr, "socket(vc)", errno);
400
                                        return (-1);
401
                                }
402
                                errno = 0;
403
                                if (connect(s, (struct sockaddr *)nsap,
404
                                            sizeof *nsap) < 0) {
405
                                        terrno = errno;
406
                                        Aerror(stderr, "connect/vc",
407
                                               errno, *nsap);
408
                                        badns |= (1 << ns);
409
                                        res_close();
410
                                        goto next_ns;
411
                                }
412
                                vc = 1;
413
                        }
414
                        /*
415
                         * Send length & message
416
                         */
417
                        putshort((u_short)buflen, (u_char*)&len);
418
#if !defined(__rtems__)
419
                        iov[0].iov_base = (caddr_t)&len;
420
                        iov[0].iov_len = INT16SZ;
421
                        iov[1].iov_base = (caddr_t)buf;
422
                        iov[1].iov_len = buflen;
423
                        if (writev(s, iov, 2) != (INT16SZ + buflen)) {
424
#else
425
                        /*
426
                         * RTEMS doesn't have writev (yet)
427
                         */
428
                        if ((write (s, &len, INT16SZ) != INT16SZ)
429
                         || (write (s, buf, buflen) != buflen)) {
430
#endif
431
                                terrno = errno;
432
                                Perror(stderr, "write failed", errno);
433
                                badns |= (1 << ns);
434
                                res_close();
435
                                goto next_ns;
436
                        }
437
                        /*
438
                         * Receive length & response
439
                         */
440
read_len:
441
                        cp = ans;
442
                        len = INT16SZ;
443
                        while ((n = read(s, (char *)cp, (int)len)) > 0) {
444
                                cp += n;
445
                                if ((len -= n) <= 0)
446
                                        break;
447
                        }
448
                        if (n <= 0) {
449
                                terrno = errno;
450
                                Perror(stderr, "read failed", errno);
451
                                res_close();
452
                                /*
453
                                 * A long running process might get its TCP
454
                                 * connection reset if the remote server was
455
                                 * restarted.  Requery the server instead of
456
                                 * trying a new one.  When there is only one
457
                                 * server, this means that a query might work
458
                                 * instead of failing.  We only allow one reset
459
                                 * per query to prevent looping.
460
                                 */
461
                                if (terrno == ECONNRESET && !connreset) {
462
                                        connreset = 1;
463
                                        res_close();
464
                                        goto same_ns;
465
                                }
466
                                res_close();
467
                                goto next_ns;
468
                        }
469
                        resplen = ns_get16(ans);
470
                        if (resplen > anssiz) {
471
                                Dprint(_res.options & RES_DEBUG,
472
                                       (stdout, ";; response truncated\n")
473
                                       );
474
                                truncated = 1;
475
                                len = anssiz;
476
                        } else
477
                                len = resplen;
478
                        if (len < HFIXEDSZ) {
479
                                /*
480
                                 * Undersized message.
481
                                 */
482
                                Dprint(_res.options & RES_DEBUG,
483
                                       (stdout, ";; undersized: %d\n", len));
484
                                terrno = EMSGSIZE;
485
                                badns |= (1 << ns);
486
                                res_close();
487
                                goto next_ns;
488
                        }
489
                        cp = ans;
490
                        while (len != 0 &&
491
                               (n = read(s, (char *)cp, (int)len)) > 0) {
492
                                cp += n;
493
                                len -= n;
494
                        }
495
                        if (n <= 0) {
496
                                terrno = errno;
497
                                Perror(stderr, "read(vc)", errno);
498
                                res_close();
499
                                goto next_ns;
500
                        }
501
                        if (truncated) {
502
                                /*
503
                                 * Flush rest of answer
504
                                 * so connection stays in synch.
505
                                 */
506
                                anhp->tc = 1;
507
                                len = resplen - anssiz;
508
                                while (len != 0) {
509
                                        char junk[PACKETSZ];
510
 
511
                                        n = (len > sizeof(junk)
512
                                             ? sizeof(junk)
513
                                             : len);
514
                                        if ((n = read(s, junk, n)) > 0)
515
                                                len -= n;
516
                                        else
517
                                                break;
518
                                }
519
                        }
520
                        /*
521
                         * The calling applicating has bailed out of
522
                         * a previous call and failed to arrange to have
523
                         * the circuit closed or the server has got
524
                         * itself confused. Anyway drop the packet and
525
                         * wait for the correct one.
526
                         */
527
                        if (hp->id != anhp->id) {
528
                                DprintQ((_res.options & RES_DEBUG) ||
529
                                        (_res.pfcode & RES_PRF_REPLY),
530
                                        (stdout, ";; old answer (unexpected):\n"),
531
                                        ans, (resplen>anssiz)?anssiz:resplen);
532
                                goto read_len;
533
                        }
534
                } else {
535
                        /*
536
                         * Use datagrams.
537
                         */
538
#ifndef NOPOLL
539
                        struct pollfd pfd;
540
                        int msec;
541
#endif
542
                        struct timeval timeout;
543
#ifndef NOSELECT
544
                        fd_set dsmask, *dsmaskp;
545
                        int dsmasklen;
546
#endif
547
                        struct sockaddr_in from;
548
                        int fromlen;
549
 
550
                        if ((s < 0) || vc) {
551
                                if (vc)
552
                                        res_close();
553
                                s = socket(PF_INET, SOCK_DGRAM, 0);
554
                                if (s < 0) {
555
#ifndef CAN_RECONNECT
556
 bad_dg_sock:
557
#endif
558
                                        terrno = errno;
559
                                        Perror(stderr, "socket(dg)", errno);
560
                                        return (-1);
561
                                }
562
                                connected = 0;
563
                        }
564
#ifndef CANNOT_CONNECT_DGRAM
565
                        /*
566
                         * On a 4.3BSD+ machine (client and server,
567
                         * actually), sending to a nameserver datagram
568
                         * port with no nameserver will cause an
569
                         * ICMP port unreachable message to be returned.
570
                         * If our datagram socket is "connected" to the
571
                         * server, we get an ECONNREFUSED error on the next
572
                         * socket operation, and select returns if the
573
                         * error message is received.  We can thus detect
574
                         * the absence of a nameserver without timing out.
575
                         * If we have sent queries to at least two servers,
576
                         * however, we don't want to remain connected,
577
                         * as we wish to receive answers from the first
578
                         * server to respond.
579
                         */
580
                        if (_res.nscount == 1 || (try == 0 && ns == 0)) {
581
                                /*
582
                                 * Connect only if we are sure we won't
583
                                 * receive a response from another server.
584
                                 */
585
                                if (!connected) {
586
                                        if (connect(s, (struct sockaddr *)nsap,
587
                                                    sizeof *nsap
588
                                                    ) < 0) {
589
                                                Aerror(stderr,
590
                                                       "connect(dg)",
591
                                                       errno, *nsap);
592
                                                badns |= (1 << ns);
593
                                                res_close();
594
                                                goto next_ns;
595
                                        }
596
                                        connected = 1;
597
                                }
598
                                if (send(s, (char*)buf, buflen, 0) != buflen) {
599
                                        Perror(stderr, "send", errno);
600
                                        badns |= (1 << ns);
601
                                        res_close();
602
                                        goto next_ns;
603
                                }
604
                        } else {
605
                                /*
606
                                 * Disconnect if we want to listen
607
                                 * for responses from more than one server.
608
                                 */
609
                                if (connected) {
610
#ifdef CAN_RECONNECT
611
                                        struct sockaddr_in no_addr;
612
 
613
                                        no_addr.sin_family = AF_INET;
614
                                        no_addr.sin_addr.s_addr = INADDR_ANY;
615
                                        no_addr.sin_port = 0;
616
                                        (void) connect(s,
617
                                                       (struct sockaddr *)
618
                                                        &no_addr,
619
                                                       sizeof no_addr);
620
#else
621
                                        int s1 = socket(PF_INET, SOCK_DGRAM,0);
622
                                        if (s1 < 0)
623
                                                goto bad_dg_sock;
624
                                        (void) dup2(s1, s);
625
                                        (void) close(s1);
626
                                        Dprint(_res.options & RES_DEBUG,
627
                                                (stdout, ";; new DG socket\n"))
628
#endif /* CAN_RECONNECT */
629
                                        connected = 0;
630
                                        errno = 0;
631
                                }
632
#endif /* !CANNOT_CONNECT_DGRAM */
633
                                if (sendto(s, (char*)buf, buflen, 0,
634
                                           (struct sockaddr *)nsap,
635
                                           sizeof *nsap)
636
                                    != buflen) {
637
                                        Aerror(stderr, "sendto", errno, *nsap);
638
                                        badns |= (1 << ns);
639
                                        res_close();
640
                                        goto next_ns;
641
                                }
642
#ifndef CANNOT_CONNECT_DGRAM
643
                        }
644
#endif /* !CANNOT_CONNECT_DGRAM */
645
 
646
                        /*
647
                         * Wait for reply
648
                         */
649
#ifndef NOPOLL
650
    othersyscall:
651
                        if (use_poll) {
652
                                msec = (_res.retrans << try) * 1000;
653
                                if (try > 0)
654
                                        msec /= _res.nscount;
655
                                if (msec <= 0)
656
                                        msec = 1000;
657
                        } else {
658
#endif
659
                                timeout.tv_sec = (_res.retrans << try);
660
                                if (try > 0)
661
                                        timeout.tv_sec /= _res.nscount;
662
                                if ((long) timeout.tv_sec <= 0)
663
                                        timeout.tv_sec = 1;
664
                                timeout.tv_usec = 0;
665
#ifndef NOPOLL
666
                        }
667
#endif
668
    wait:
669
                        if (s < 0) {
670
                                Perror(stderr, "s out-of-bounds", EMFILE);
671
                                res_close();
672
                                goto next_ns;
673
                        }
674
#ifndef NOPOLL
675
                        if (use_poll) {
676
                                struct sigaction sa, osa;
677
                                int sigsys_installed = 0;
678
 
679
                                pfd.fd = s;
680
                                pfd.events = POLLIN;
681
                                if (use_poll == 1) {
682
                                        bzero(&sa, sizeof(sa));
683
                                        sa.sa_handler = SIG_IGN;
684
                                        if (sigaction(SIGSYS, &sa, &osa) >= 0)
685
                                                sigsys_installed = 1;
686
                                }
687
                                n = poll(&pfd, 1, msec);
688
                                if (sigsys_installed == 1) {
689
                                        int oerrno = errno;
690
                                        sigaction(SIGSYS, &osa, NULL);
691
                                        errno = oerrno;
692
                                }
693
                                /* XXX why does nosys() return EINVAL? */
694
                                if (n < 0 && (errno == ENOSYS ||
695
                                    errno == EINVAL)) {
696
                                        use_poll = 0;
697
                                        goto othersyscall;
698
                                } else if (use_poll == 1)
699
                                        use_poll = 2;
700
                                if (n < 0) {
701
                                        if (errno == EINTR)
702
                                                goto wait;
703
                                        Perror(stderr, "poll", errno);
704
                                        res_close();
705
                                        goto next_ns;
706
                                }
707
                        } else {
708
#endif
709
#ifndef NOSELECT
710
                                dsmasklen = howmany(s + 1, NFDBITS) *
711
                                            sizeof(fd_mask);
712
                                if (dsmasklen > sizeof(fd_set)) {
713
                                        dsmaskp = (fd_set *)malloc(dsmasklen);
714
                                        if (dsmaskp == NULL) {
715
                                                res_close();
716
                                                goto next_ns;
717
                                        }
718
                                } else
719
                                        dsmaskp = &dsmask;
720
                                /* only zero what we need */
721
                                bzero((char *)dsmaskp, dsmasklen);
722
                                FD_SET(s, dsmaskp);
723
                                n = select(s + 1, dsmaskp, (fd_set *)NULL,
724
                                           (fd_set *)NULL, &timeout);
725
                                if (dsmaskp != &dsmask)
726
                                        free(dsmaskp);
727
                                if (n < 0) {
728
                                        if (errno == EINTR)
729
                                                goto wait;
730
                                        Perror(stderr, "select", errno);
731
                                        res_close();
732
                                        goto next_ns;
733
                                }
734
#endif
735
#ifndef NOPOLL
736
                        }
737
#endif
738
 
739
#ifdef NOSELECT
740
                        setsockopt (s, SOL_SOCKET, SO_RCVTIMEO, &timeout, sizeof timeout);
741
#else
742
                        if (n == 0) {
743
                                /*
744
                                 * timeout
745
                                 */
746
                                Dprint(_res.options & RES_DEBUG,
747
                                       (stdout, ";; timeout\n"));
748
                                gotsomewhere = 1;
749
                                res_close();
750
                                goto next_ns;
751
                        }
752
#endif
753
                        errno = 0;
754
                        fromlen = sizeof(struct sockaddr_in);
755
                        resplen = recvfrom(s, (char*)ans, anssiz, 0,
756
                                           (struct sockaddr *)&from, &fromlen);
757
                        if (resplen <= 0) {
758
#ifdef NOSELECT
759
                                if (errno == ETIMEDOUT) {
760
                                        Dprint(_res.options & RES_DEBUG,
761
                                               (stdout, ";; timeout\n"));
762
                                        gotsomewhere = 1;
763
                                        res_close();
764
                                        goto next_ns;
765
                                }
766
#endif
767
                                Perror(stderr, "recvfrom", errno);
768
                                res_close();
769
                                goto next_ns;
770
                        }
771
                        gotsomewhere = 1;
772
                        if (resplen < HFIXEDSZ) {
773
                                /*
774
                                 * Undersized message.
775
                                 */
776
                                Dprint(_res.options & RES_DEBUG,
777
                                       (stdout, ";; undersized: %d\n",
778
                                        resplen));
779
                                terrno = EMSGSIZE;
780
                                badns |= (1 << ns);
781
                                res_close();
782
                                goto next_ns;
783
                        }
784
                        if (hp->id != anhp->id) {
785
                                /*
786
                                 * response from old query, ignore it.
787
                                 * XXX - potential security hazard could
788
                                 *       be detected here.
789
                                 */
790
                                DprintQ((_res.options & RES_DEBUG) ||
791
                                        (_res.pfcode & RES_PRF_REPLY),
792
                                        (stdout, ";; old answer:\n"),
793
                                        ans, (resplen>anssiz)?anssiz:resplen);
794
                                goto wait;
795
                        }
796
#ifdef CHECK_SRVR_ADDR
797
                        if (!(_res.options & RES_INSECURE1) &&
798
                            !res_isourserver(&from)) {
799
                                /*
800
                                 * response from wrong server? ignore it.
801
                                 * XXX - potential security hazard could
802
                                 *       be detected here.
803
                                 */
804
                                DprintQ((_res.options & RES_DEBUG) ||
805
                                        (_res.pfcode & RES_PRF_REPLY),
806
                                        (stdout, ";; not our server:\n"),
807
                                        ans, (resplen>anssiz)?anssiz:resplen);
808
                                goto wait;
809
                        }
810
#endif
811
                        if (!(_res.options & RES_INSECURE2) &&
812
                            !res_queriesmatch(buf, buf + buflen,
813
                                              ans, ans + anssiz)) {
814
                                /*
815
                                 * response contains wrong query? ignore it.
816
                                 * XXX - potential security hazard could
817
                                 *       be detected here.
818
                                 */
819
                                DprintQ((_res.options & RES_DEBUG) ||
820
                                        (_res.pfcode & RES_PRF_REPLY),
821
                                        (stdout, ";; wrong query name:\n"),
822
                                        ans, (resplen>anssiz)?anssiz:resplen);
823
                                goto wait;
824
                        }
825
                        if (anhp->rcode == SERVFAIL ||
826
                            anhp->rcode == NOTIMP ||
827
                            anhp->rcode == REFUSED) {
828
                                DprintQ(_res.options & RES_DEBUG,
829
                                        (stdout, "server rejected query:\n"),
830
                                        ans, (resplen>anssiz)?anssiz:resplen);
831
                                badns |= (1 << ns);
832
                                res_close();
833
                                /* don't retry if called from dig */
834
                                if (!_res.pfcode)
835
                                        goto next_ns;
836
                        }
837
                        if (!(_res.options & RES_IGNTC) && anhp->tc) {
838
                                /*
839
                                 * get rest of answer;
840
                                 * use TCP with same server.
841
                                 */
842
                                Dprint(_res.options & RES_DEBUG,
843
                                       (stdout, ";; truncated answer\n"));
844
                                v_circuit = 1;
845
                                res_close();
846
                                goto same_ns;
847
                        }
848
                } /*if vc/dg*/
849
                Dprint((_res.options & RES_DEBUG) ||
850
                       ((_res.pfcode & RES_PRF_REPLY) &&
851
                        (_res.pfcode & RES_PRF_HEAD1)),
852
                       (stdout, ";; got answer:\n"));
853
                DprintQ((_res.options & RES_DEBUG) ||
854
                        (_res.pfcode & RES_PRF_REPLY),
855
                        (stdout, "%s", ""),
856
                        ans, (resplen>anssiz)?anssiz:resplen);
857
                /*
858
                 * If using virtual circuits, we assume that the first server
859
                 * is preferred over the rest (i.e. it is on the local
860
                 * machine) and only keep that one open.
861
                 * If we have temporarily opened a virtual circuit,
862
                 * or if we haven't been asked to keep a socket open,
863
                 * close the socket.
864
                 */
865
                if ((v_circuit && (!(_res.options & RES_USEVC) || ns != 0)) ||
866
                    !(_res.options & RES_STAYOPEN)) {
867
                        res_close();
868
                }
869
                if (Rhook) {
870
                        int done = 0, loops = 0;
871
 
872
                        do {
873
                                res_sendhookact act;
874
 
875
                                act = (*Rhook)(nsap, buf, buflen,
876
                                               ans, anssiz, &resplen);
877
                                switch (act) {
878
                                case res_goahead:
879
                                case res_done:
880
                                        done = 1;
881
                                        break;
882
                                case res_nextns:
883
                                        res_close();
884
                                        goto next_ns;
885
                                case res_modified:
886
                                        /* give the hook another try */
887
                                        if (++loops < 42) /*doug adams*/
888
                                                break;
889
                                        /*FALLTHROUGH*/
890
                                case res_error:
891
                                        /*FALLTHROUGH*/
892
                                default:
893
                                        return (-1);
894
                                }
895
                        } while (!done);
896
 
897
                }
898
                return (resplen);
899
    next_ns: ;
900
           } /*foreach ns*/
901
        } /*foreach retry*/
902
        res_close();
903
        if (!v_circuit) {
904
                if (!gotsomewhere)
905
                        errno = ECONNREFUSED;   /* no nameservers found */
906
                else
907
                        errno = ETIMEDOUT;      /* no answer obtained */
908
        } else
909
                errno = terrno;
910
        return (-1);
911
}
912
 
913
/*
914
 * This routine is for closing the socket if a virtual circuit is used and
915
 * the program wants to close it.  This provides support for endhostent()
916
 * which expects to close the socket.
917
 *
918
 * This routine is not expected to be user visible.
919
 */
920
void
921
res_close()
922
{
923
        if (s >= 0) {
924
                (void) close(s);
925
                s = -1;
926
                connected = 0;
927
                vc = 0;
928
        }
929
}

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