DANE: treat "no action taken" response from library as a non-error
[exim.git] / src / src / dns.c
CommitLineData
059ec3d9
PH
1/*************************************************
2* Exim - an Internet mail transport agent *
3*************************************************/
4
80fea873 5/* Copyright (c) University of Cambridge 1995 - 2016 */
059ec3d9
PH
6/* See the file NOTICE for conditions of use and distribution. */
7
8/* Functions for interfacing with the DNS. */
9
10#include "exim.h"
11
12
059ec3d9 13
bef5a11f
PH
14/*************************************************
15* Fake DNS resolver *
16*************************************************/
17
18/* This function is called instead of res_search() when Exim is running in its
19test harness. It recognizes some special domain names, and uses them to force
433a2980
PH
20failure and retry responses (optionally with a delay). Otherwise, it calls an
21external utility that mocks-up a nameserver, if it can find the utility.
22If not, it passes its arguments on to res_search(). The fake nameserver may
23also return a code specifying that the name should be passed on.
bef5a11f
PH
24
25Background: the original test suite required a real nameserver to carry the
8e013028 26test zones, whereas the new test suite has the fake server for portability. This
e7726cbf 27code supports both.
bef5a11f
PH
28
29Arguments:
e7726cbf 30 domain the domain name
bef5a11f
PH
31 type the DNS record type
32 answerptr where to put the answer
33 size size of the answer area
34
35Returns: length of returned data, or -1 on error (h_errno set)
36*/
37
38static int
1dc92d5a 39fakens_search(const uschar *domain, int type, uschar *answerptr, int size)
bef5a11f 40{
e7726cbf 41int len = Ustrlen(domain);
433a2980 42int asize = size; /* Locally modified */
e7726cbf 43uschar name[256];
433a2980
PH
44uschar utilname[256];
45uschar *aptr = answerptr; /* Locally modified */
46struct stat statbuf;
47
48/* Remove terminating dot. */
e7726cbf
PH
49
50if (domain[len - 1] == '.') len--;
51Ustrncpy(name, domain, len);
52name[len] = 0;
bef5a11f 53
433a2980
PH
54/* Look for the fakens utility, and if it exists, call it. */
55
5f3d0983
HSHR
56(void)string_format(utilname, sizeof(utilname), "%s/bin/fakens",
57 config_main_directory);
433a2980
PH
58
59if (stat(CS utilname, &statbuf) >= 0)
bef5a11f 60 {
433a2980
PH
61 pid_t pid;
62 int infd, outfd, rc;
63 uschar *argv[5];
64
3735e326 65 DEBUG(D_dns) debug_printf("DNS lookup of %s (%s) using fakens\n", name, dns_text_type(type));
433a2980
PH
66
67 argv[0] = utilname;
5f3d0983 68 argv[1] = config_main_directory;
433a2980
PH
69 argv[2] = name;
70 argv[3] = dns_text_type(type);
71 argv[4] = NULL;
72
73 pid = child_open(argv, NULL, 0000, &infd, &outfd, FALSE);
74 if (pid < 0)
75 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "failed to run fakens: %s",
76 strerror(errno));
77
78 len = 0;
79 rc = -1;
80 while (asize > 0 && (rc = read(outfd, aptr, asize)) > 0)
81 {
82 len += rc;
83 aptr += rc; /* Don't modify the actual arguments, because they */
84 asize -= rc; /* may need to be passed on to res_search(). */
85 }
bef5a11f 86
aa7751be 87 /* If we ran out of output buffer before exhausting the return,
1fb7660f
JH
88 carry on reading and counting it. */
89
90 if (asize == 0)
91 while ((rc = read(outfd, name, sizeof(name))) > 0)
92 len += rc;
93
433a2980
PH
94 if (rc < 0)
95 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "read from fakens failed: %s",
96 strerror(errno));
bef5a11f 97
433a2980 98 switch(child_close(pid, 0))
bef5a11f 99 {
433a2980
PH
100 case 0: return len;
101 case 1: h_errno = HOST_NOT_FOUND; return -1;
102 case 2: h_errno = TRY_AGAIN; return -1;
103 default:
104 case 3: h_errno = NO_RECOVERY; return -1;
105 case 4: h_errno = NO_DATA; return -1;
106 case 5: /* Pass on to res_search() */
107 DEBUG(D_dns) debug_printf("fakens returned PASS_ON\n");
bef5a11f
PH
108 }
109 }
8e013028
HSHR
110else
111 {
4cea764f 112 DEBUG(D_dns) debug_printf("fakens (%s) not found\n", utilname);
8e013028 113 }
bef5a11f 114
433a2980 115/* fakens utility not found, or it returned "pass on" */
bef5a11f 116
433a2980 117DEBUG(D_dns) debug_printf("passing %s on to res_search()\n", domain);
e7726cbf
PH
118
119return res_search(CS domain, C_IN, type, answerptr, size);
bef5a11f
PH
120}
121
122
059ec3d9
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123
124/*************************************************
125* Initialize and configure resolver *
126*************************************************/
127
128/* Initialize the resolver and the storage for holding DNS answers if this is
129the first time we have been here, and set the resolver options.
130
131Arguments:
132 qualify_single TRUE to set the RES_DEFNAMES option
133 search_parents TRUE to set the RES_DNSRCH option
8c51eead 134 use_dnssec TRUE to set the RES_USE_DNSSEC option
059ec3d9
PH
135
136Returns: nothing
137*/
138
139void
8c51eead 140dns_init(BOOL qualify_single, BOOL search_parents, BOOL use_dnssec)
059ec3d9 141{
5bfb4cdf
PP
142res_state resp = os_get_dns_resolver_res();
143
144if ((resp->options & RES_INIT) == 0)
059ec3d9 145 {
5bfb4cdf
PP
146 DEBUG(D_resolver) resp->options |= RES_DEBUG; /* For Cygwin */
147 os_put_dns_resolver_res(resp);
059ec3d9 148 res_init();
5bfb4cdf
PP
149 DEBUG(D_resolver) resp->options |= RES_DEBUG;
150 os_put_dns_resolver_res(resp);
059ec3d9
PH
151 }
152
5bfb4cdf
PP
153resp->options &= ~(RES_DNSRCH | RES_DEFNAMES);
154resp->options |= (qualify_single? RES_DEFNAMES : 0) |
059ec3d9 155 (search_parents? RES_DNSRCH : 0);
5bfb4cdf
PP
156if (dns_retrans > 0) resp->retrans = dns_retrans;
157if (dns_retry > 0) resp->retry = dns_retry;
e97d1f08
PP
158
159#ifdef RES_USE_EDNS0
160if (dns_use_edns0 >= 0)
161 {
162 if (dns_use_edns0)
5bfb4cdf 163 resp->options |= RES_USE_EDNS0;
e97d1f08 164 else
5bfb4cdf 165 resp->options &= ~RES_USE_EDNS0;
e97d1f08
PP
166 DEBUG(D_resolver)
167 debug_printf("Coerced resolver EDNS0 support %s.\n",
168 dns_use_edns0 ? "on" : "off");
169 }
170#else
171if (dns_use_edns0 >= 0)
172 DEBUG(D_resolver)
173 debug_printf("Unable to %sset EDNS0 without resolver support.\n",
174 dns_use_edns0 ? "" : "un");
175#endif
5bfb4cdf 176
1f4a55da
PP
177#ifndef DISABLE_DNSSEC
178# ifdef RES_USE_DNSSEC
179# ifndef RES_USE_EDNS0
180# error Have RES_USE_DNSSEC but not RES_USE_EDNS0? Something hinky ...
181# endif
8c51eead
JH
182if (use_dnssec)
183 resp->options |= RES_USE_DNSSEC;
0fbd9bff 184if (dns_dnssec_ok >= 0)
1f4a55da 185 {
0fbd9bff 186 if (dns_use_edns0 == 0 && dns_dnssec_ok != 0)
1f4a55da
PP
187 {
188 DEBUG(D_resolver)
0fbd9bff 189 debug_printf("CONFLICT: dns_use_edns0 forced false, dns_dnssec_ok forced true, ignoring latter!\n");
1f4a55da
PP
190 }
191 else
192 {
0fbd9bff 193 if (dns_dnssec_ok)
1f4a55da
PP
194 resp->options |= RES_USE_DNSSEC;
195 else
196 resp->options &= ~RES_USE_DNSSEC;
197 DEBUG(D_resolver) debug_printf("Coerced resolver DNSSEC support %s.\n",
0fbd9bff 198 dns_dnssec_ok ? "on" : "off");
1f4a55da
PP
199 }
200 }
201# else
0fbd9bff 202if (dns_dnssec_ok >= 0)
1f4a55da
PP
203 DEBUG(D_resolver)
204 debug_printf("Unable to %sset DNSSEC without resolver support.\n",
0fbd9bff 205 dns_dnssec_ok ? "" : "un");
8c51eead
JH
206if (use_dnssec)
207 DEBUG(D_resolver)
93d4b03a 208 debug_printf("Unable to set DNSSEC without resolver support.\n");
1f4a55da
PP
209# endif
210#endif /* DISABLE_DNSSEC */
211
5bfb4cdf 212os_put_dns_resolver_res(resp);
059ec3d9
PH
213}
214
215
216
217/*************************************************
218* Build key name for PTR records *
219*************************************************/
220
221/* This function inverts an IP address and adds the relevant domain, to produce
222a name that can be used to look up PTR records.
223
224Arguments:
225 string the IP address as a string
226 buffer a suitable buffer, long enough to hold the result
227
228Returns: nothing
229*/
230
231void
55414b25 232dns_build_reverse(const uschar *string, uschar *buffer)
059ec3d9 233{
55414b25 234const uschar *p = string + Ustrlen(string);
059ec3d9
PH
235uschar *pp = buffer;
236
237/* Handle IPv4 address */
238
239#if HAVE_IPV6
240if (Ustrchr(string, ':') == NULL)
241#endif
242 {
243 int i;
244 for (i = 0; i < 4; i++)
245 {
55414b25 246 const uschar *ppp = p;
059ec3d9
PH
247 while (ppp > string && ppp[-1] != '.') ppp--;
248 Ustrncpy(pp, ppp, p - ppp);
249 pp += p - ppp;
250 *pp++ = '.';
251 p = ppp - 1;
252 }
253 Ustrcpy(pp, "in-addr.arpa");
254 }
255
256/* Handle IPv6 address; convert to binary so as to fill out any
257abbreviation in the textual form. */
258
259#if HAVE_IPV6
260else
261 {
262 int i;
263 int v6[4];
264 (void)host_aton(string, v6);
265
266 /* The original specification for IPv6 reverse lookup was to invert each
267 nibble, and look in the ip6.int domain. The domain was subsequently
268 changed to ip6.arpa. */
269
270 for (i = 3; i >= 0; i--)
271 {
272 int j;
273 for (j = 0; j < 32; j += 4)
274 {
275 sprintf(CS pp, "%x.", (v6[i] >> j) & 15);
276 pp += 2;
277 }
278 }
279 Ustrcpy(pp, "ip6.arpa.");
280
281 /* Another way of doing IPv6 reverse lookups was proposed in conjunction
282 with A6 records. However, it fell out of favour when they did. The
283 alternative was to construct a binary key, and look in ip6.arpa. I tried
284 to make this code do that, but I could not make it work on Solaris 8. The
285 resolver seems to lose the initial backslash somehow. However, now that
286 this style of reverse lookup has been dropped, it doesn't matter. These
287 lines are left here purely for historical interest. */
288
289 /**************************************************
290 Ustrcpy(pp, "\\[x");
291 pp += 3;
292
293 for (i = 0; i < 4; i++)
294 {
295 sprintf(pp, "%08X", v6[i]);
296 pp += 8;
297 }
298 Ustrcpy(pp, "].ip6.arpa.");
299 **************************************************/
300
301 }
302#endif
303}
304
305
306
307
2a407b17
JH
308/* Increment the aptr in dnss, checking against dnsa length.
309Return: TRUE for a bad result
310*/
311static BOOL
312dnss_inc(dns_answer * dnsa, dns_scan * dnss, unsigned delta)
313{
314return (dnss->aptr += delta) >= dnsa->answer + dnsa->answerlen;
315}
316
059ec3d9
PH
317/*************************************************
318* Get next DNS record from answer block *
319*************************************************/
320
321/* Call this with reset == RESET_ANSWERS to scan the answer block, reset ==
e5a9dba6
PH
322RESET_AUTHORITY to scan the authority records, reset == RESET_ADDITIONAL to
323scan the additional records, and reset == RESET_NEXT to get the next record.
324The result is in static storage which must be copied if it is to be preserved.
059ec3d9
PH
325
326Arguments:
327 dnsa pointer to dns answer block
328 dnss pointer to dns scan block
329 reset option specifing what portion to scan, as described above
330
331Returns: next dns record, or NULL when no more
332*/
333
334dns_record *
335dns_next_rr(dns_answer *dnsa, dns_scan *dnss, int reset)
336{
337HEADER *h = (HEADER *)dnsa->answer;
338int namelen;
339
2a407b17
JH
340char * trace = NULL;
341#ifdef rr_trace
342# define TRACE DEBUG(D_dns)
343#else
344trace = trace;
345# define TRACE if (FALSE)
346#endif
347
059ec3d9
PH
348/* Reset the saved data when requested to, and skip to the first required RR */
349
350if (reset != RESET_NEXT)
351 {
2a407b17 352 TRACE debug_printf("%s: reset\n", __FUNCTION__);
059ec3d9
PH
353 dnss->rrcount = ntohs(h->qdcount);
354 dnss->aptr = dnsa->answer + sizeof(HEADER);
355
356 /* Skip over questions; failure to expand the name just gives up */
357
358 while (dnss->rrcount-- > 0)
359 {
2a407b17 360 TRACE trace = "Q-namelen";
059ec3d9 361 namelen = dn_expand(dnsa->answer, dnsa->answer + dnsa->answerlen,
2a407b17
JH
362 dnss->aptr, (DN_EXPAND_ARG4_TYPE) &dnss->srr.name, DNS_MAXNAME);
363 if (namelen < 0) goto null_return;
364 /* skip name & type & class */
365 TRACE trace = "Q-skip";
366 if (dnss_inc(dnsa, dnss, namelen+4)) goto null_return;
059ec3d9
PH
367 }
368
369 /* Get the number of answer records. */
370
371 dnss->rrcount = ntohs(h->ancount);
372
e5a9dba6
PH
373 /* Skip over answers if we want to look at the authority section. Also skip
374 the NS records (i.e. authority section) if wanting to look at the additional
059ec3d9
PH
375 records. */
376
2a407b17
JH
377 if (reset == RESET_ADDITIONAL)
378 {
379 TRACE debug_printf("%s: additional\n", __FUNCTION__);
380 dnss->rrcount += ntohs(h->nscount);
381 }
e5a9dba6
PH
382
383 if (reset == RESET_AUTHORITY || reset == RESET_ADDITIONAL)
059ec3d9 384 {
2a407b17
JH
385 TRACE if (reset == RESET_AUTHORITY)
386 debug_printf("%s: authority\n", __FUNCTION__);
059ec3d9
PH
387 while (dnss->rrcount-- > 0)
388 {
2a407b17 389 TRACE trace = "A-namelen";
059ec3d9 390 namelen = dn_expand(dnsa->answer, dnsa->answer + dnsa->answerlen,
2a407b17
JH
391 dnss->aptr, (DN_EXPAND_ARG4_TYPE) &dnss->srr.name, DNS_MAXNAME);
392 if (namelen < 0) goto null_return;
393 /* skip name, type, class & TTL */
394 TRACE trace = "A-hdr";
395 if (dnss_inc(dnsa, dnss, namelen+8)) goto null_return;
059ec3d9 396 GETSHORT(dnss->srr.size, dnss->aptr); /* size of data portion */
2a407b17
JH
397 /* skip over it */
398 TRACE trace = "A-skip";
399 if (dnss_inc(dnsa, dnss, dnss->srr.size)) goto null_return;
059ec3d9 400 }
2a407b17 401 dnss->rrcount = reset == RESET_AUTHORITY
e5a9dba6 402 ? ntohs(h->nscount) : ntohs(h->arcount);
059ec3d9 403 }
2a407b17 404 TRACE debug_printf("%s: %d RRs to read\n", __FUNCTION__, dnss->rrcount);
059ec3d9 405 }
2a407b17
JH
406else
407 TRACE debug_printf("%s: next (%d left)\n", __FUNCTION__, dnss->rrcount);
059ec3d9 408
059ec3d9
PH
409/* The variable dnss->aptr is now pointing at the next RR, and dnss->rrcount
410contains the number of RR records left. */
411
412if (dnss->rrcount-- <= 0) return NULL;
413
414/* If expanding the RR domain name fails, behave as if no more records
415(something safe). */
416
2a407b17 417TRACE trace = "R-namelen";
059ec3d9 418namelen = dn_expand(dnsa->answer, dnsa->answer + dnsa->answerlen, dnss->aptr,
2a407b17
JH
419 (DN_EXPAND_ARG4_TYPE) &dnss->srr.name, DNS_MAXNAME);
420if (namelen < 0) goto null_return;
059ec3d9
PH
421
422/* Move the pointer past the name and fill in the rest of the data structure
423from the following bytes. */
424
2a407b17
JH
425TRACE trace = "R-name";
426if (dnss_inc(dnsa, dnss, namelen)) goto null_return;
427
428GETSHORT(dnss->srr.type, dnss->aptr); /* Record type */
429TRACE trace = "R-class";
430if (dnss_inc(dnsa, dnss, 2)) goto null_return; /* Don't want class */
431GETLONG(dnss->srr.ttl, dnss->aptr); /* TTL */
432GETSHORT(dnss->srr.size, dnss->aptr); /* Size of data portion */
433dnss->srr.data = dnss->aptr; /* The record's data follows */
434
435/* Unchecked increment ok here since no further access on this iteration;
436will be checked on next at "R-name". */
437
438dnss->aptr += dnss->srr.size; /* Advance to next RR */
059ec3d9
PH
439
440/* Return a pointer to the dns_record structure within the dns_answer. This is
441for convenience so that the scans can use nice-looking for loops. */
442
2a407b17
JH
443return &dnss->srr;
444
445null_return:
446 TRACE debug_printf("%s: terminate (%d RRs left). Last op: %s\n",
447 __FUNCTION__, dnss->rrcount, trace);
448 dnss->rrcount = 0;
449 return NULL;
059ec3d9
PH
450}
451
452
8db90b31
HSHR
453/* Extract the AUTHORITY information from the answer. If the
454answer isn't authoritive (AA not set), we do not extract anything.
455
456The AUTHORITIVE section contains NS records if
457the name in question was found, it contains a SOA record
458otherwise. (This is just from experience and some tests, is there
459some spec?)
460
461We've cycle through the AUTHORITY section, since it may contain
462other records (e.g. NSEC3) too. */
09b80b4e
JH
463
464static const uschar *
465dns_extract_auth_name(const dns_answer * dnsa) /* FIXME: const dns_answer */
9820a77f 466{
09b80b4e
JH
467dns_scan dnss;
468dns_record * rr;
469HEADER * h = (HEADER *) dnsa->answer;
470
471if (!h->nscount || !h->aa) return NULL;
472for (rr = dns_next_rr((dns_answer*) dnsa, &dnss, RESET_AUTHORITY);
473 rr;
474 rr = dns_next_rr((dns_answer*) dnsa, &dnss, RESET_NEXT))
47c20958 475 if (rr->type == (h->ancount ? T_NS : T_SOA)) return rr->name;
09b80b4e 476return NULL;
9820a77f
HSHR
477}
478
479
059ec3d9
PH
480
481
482/*************************************************
1f4a55da
PP
483* Return whether AD bit set in DNS result *
484*************************************************/
485
486/* We do not perform DNSSEC work ourselves; if the administrator has installed
487a verifying resolver which sets AD as appropriate, though, we'll use that.
9820a77f 488(AD = Authentic Data, AA = Authoritive Answer)
1f4a55da
PP
489
490Argument: pointer to dns answer block
491Returns: bool indicating presence of AD bit
492*/
493
494BOOL
4a142059 495dns_is_secure(const dns_answer * dnsa)
1f4a55da
PP
496{
497#ifdef DISABLE_DNSSEC
498DEBUG(D_dns)
499 debug_printf("DNSSEC support disabled at build-time; dns_is_secure() false\n");
500return FALSE;
501#else
09b80b4e
JH
502HEADER * h = (HEADER *) dnsa->answer;
503const uschar * auth_name;
504const uschar * trusted;
9820a77f
HSHR
505
506if (h->ad) return TRUE;
9820a77f 507
09b80b4e
JH
508/* If the resolver we ask is authoritive for the domain in question, it
509* may not set the AD but the AA bit. If we explicitly trust
510* the resolver for that domain (via a domainlist in dns_trust_aa),
511* we return TRUE to indicate a secure answer.
512*/
9820a77f 513
09b80b4e
JH
514if ( !h->aa
515 || !dns_trust_aa
25bf2076
HSHR
516 || !(trusted = expand_string(dns_trust_aa))
517 || !*trusted
09b80b4e
JH
518 || !(auth_name = dns_extract_auth_name(dnsa))
519 || OK != match_isinlist(auth_name, &trusted, 0, NULL, NULL,
94431adb 520 MCL_DOMAIN, TRUE, NULL)
09b80b4e
JH
521 )
522 return FALSE;
9820a77f 523
09b80b4e
JH
524DEBUG(D_dns) debug_printf("DNS faked the AD bit "
525 "(got AA and matched with dns_trust_aa (%s in %s))\n",
526 auth_name, dns_trust_aa);
9820a77f 527
09b80b4e 528return TRUE;
1f4a55da
PP
529#endif
530}
531
4a142059
JH
532static void
533dns_set_insecure(dns_answer * dnsa)
534{
e87c01c7 535#ifndef DISABLE_DNSSEC
4a142059
JH
536HEADER * h = (HEADER *)dnsa->answer;
537h->ad = 0;
e87c01c7 538#endif
4a142059
JH
539}
540
221dff13
HSHR
541/************************************************
542 * Check whether the AA bit is set *
543 * We need this to warn if we requested AD *
9820a77f 544 * from an authoritive server *
221dff13
HSHR
545 ************************************************/
546
547BOOL
548dns_is_aa(const dns_answer *dnsa)
549{
e87c01c7
MH
550#ifdef DISABLE_DNSSEC
551return FALSE;
552#else
221dff13 553return ((HEADER*)dnsa->answer)->aa;
e87c01c7 554#endif
221dff13 555}
1f4a55da
PP
556
557
558
559/*************************************************
059ec3d9
PH
560* Turn DNS type into text *
561*************************************************/
562
885ccd3e
PH
563/* Turn the coded record type into a string for printing. All those that Exim
564uses should be included here.
059ec3d9
PH
565
566Argument: record type
567Returns: pointer to string
568*/
569
570uschar *
571dns_text_type(int t)
572{
573switch(t)
574 {
33397d19
PH
575 case T_A: return US"A";
576 case T_MX: return US"MX";
577 case T_AAAA: return US"AAAA";
578 case T_A6: return US"A6";
579 case T_TXT: return US"TXT";
eae0036b 580 case T_SPF: return US"SPF";
33397d19 581 case T_PTR: return US"PTR";
885ccd3e 582 case T_SOA: return US"SOA";
33397d19
PH
583 case T_SRV: return US"SRV";
584 case T_NS: return US"NS";
8e669ac1 585 case T_CNAME: return US"CNAME";
1e06383a 586 case T_TLSA: return US"TLSA";
33397d19 587 default: return US"?";
059ec3d9
PH
588 }
589}
590
591
592
593/*************************************************
594* Cache a failed DNS lookup result *
595*************************************************/
596
597/* We cache failed lookup results so as not to experience timeouts many
598times for the same domain. We need to retain the resolver options because they
599may change. For successful lookups, we rely on resolver and/or name server
600caching.
601
602Arguments:
603 name the domain name
604 type the lookup type
605 rc the return code
606
607Returns: the return code
608*/
609
610static int
1dc92d5a 611dns_return(const uschar * name, int type, int rc)
059ec3d9 612{
5bfb4cdf 613res_state resp = os_get_dns_resolver_res();
059ec3d9
PH
614tree_node *node = store_get_perm(sizeof(tree_node) + 290);
615sprintf(CS node->name, "%.255s-%s-%lx", name, dns_text_type(type),
f794c12b 616 (unsigned long) resp->options);
059ec3d9
PH
617node->data.val = rc;
618(void)tree_insertnode(&tree_dns_fails, node);
619return rc;
620}
621
059ec3d9
PH
622/*************************************************
623* Do basic DNS lookup *
624*************************************************/
625
626/* Call the resolver to look up the given domain name, using the given type,
627and check the result. The error code TRY_AGAIN is documented as meaning "non-
628Authoritive Host not found, or SERVERFAIL". Sometimes there are badly set
629up nameservers that produce this error continually, so there is the option of
630providing a list of domains for which this is treated as a non-existent
631host.
632
633Arguments:
634 dnsa pointer to dns_answer structure
635 name name to look up
636 type type of DNS record required (T_A, T_MX, etc)
637
638Returns: DNS_SUCCEED successful lookup
639 DNS_NOMATCH name not found (NXDOMAIN)
640 or name contains illegal characters (if checking)
30e18802 641 or name is an IP address (for IP address lookup)
059ec3d9
PH
642 DNS_NODATA domain exists, but no data for this type (NODATA)
643 DNS_AGAIN soft failure, try again later
644 DNS_FAIL DNS failure
645*/
646
647int
1dc92d5a 648dns_basic_lookup(dns_answer *dnsa, const uschar *name, int type)
059ec3d9
PH
649{
650#ifndef STAND_ALONE
7156b1ef 651int rc = -1;
55414b25 652const uschar *save_domain;
059ec3d9 653#endif
5bfb4cdf 654res_state resp = os_get_dns_resolver_res();
059ec3d9
PH
655
656tree_node *previous;
657uschar node_name[290];
658
659/* DNS lookup failures of any kind are cached in a tree. This is mainly so that
660a timeout on one domain doesn't happen time and time again for messages that
661have many addresses in the same domain. We rely on the resolver and name server
662caching for successful lookups. */
663
664sprintf(CS node_name, "%.255s-%s-%lx", name, dns_text_type(type),
f794c12b 665 (unsigned long) resp->options);
059ec3d9
PH
666previous = tree_search(tree_dns_fails, node_name);
667if (previous != NULL)
668 {
669 DEBUG(D_dns) debug_printf("DNS lookup of %.255s-%s: using cached value %s\n",
670 name, dns_text_type(type),
671 (previous->data.val == DNS_NOMATCH)? "DNS_NOMATCH" :
672 (previous->data.val == DNS_NODATA)? "DNS_NODATA" :
673 (previous->data.val == DNS_AGAIN)? "DNS_AGAIN" :
674 (previous->data.val == DNS_FAIL)? "DNS_FAIL" : "??");
675 return previous->data.val;
676 }
677
8c5d388a 678#ifdef SUPPORT_I18N
9d4319df
JH
679/* Convert all names to a-label form before doing lookup */
680 {
681 uschar * alabel;
682 uschar * errstr = NULL;
766e7a65
JH
683 DEBUG(D_dns) if (string_is_utf8(name))
684 debug_printf("convert utf8 '%s' to alabel for for lookup\n", name);
9d4319df
JH
685 if ((alabel = string_domain_utf8_to_alabel(name, &errstr)), errstr)
686 {
687 DEBUG(D_dns)
37bf366e 688 debug_printf("DNS name '%s' utf8 conversion to alabel failed: %s\n", name,
9d4319df
JH
689 errstr);
690 host_find_failed_syntax = TRUE;
691 return DNS_NOMATCH;
692 }
693 name = alabel;
694 }
695#endif
696
059ec3d9
PH
697/* If configured, check the hygene of the name passed to lookup. Otherwise,
698although DNS lookups may give REFUSED at the lower level, some resolvers
699turn this into TRY_AGAIN, which is silly. Give a NOMATCH return, since such
700domains cannot be in the DNS. The check is now done by a regular expression;
701give it space for substring storage to save it having to get its own if the
702regex has substrings that are used - the default uses a conditional.
703
704This test is omitted for PTR records. These occur only in calls from the dnsdb
705lookup, which constructs the names itself, so they should be OK. Besides,
706bitstring labels don't conform to normal name syntax. (But the aren't used any
707more.)
708
709For SRV records, we omit the initial _smtp._tcp. components at the start. */
710
711#ifndef STAND_ALONE /* Omit this for stand-alone tests */
712
482d1455 713if (check_dns_names_pattern[0] != 0 && type != T_PTR && type != T_TXT)
059ec3d9 714 {
1dc92d5a 715 const uschar *checkname = name;
059ec3d9
PH
716 int ovector[3*(EXPAND_MAXN+1)];
717
476be7e2 718 dns_pattern_init();
059ec3d9
PH
719
720 /* For an SRV lookup, skip over the first two components (the service and
721 protocol names, which both start with an underscore). */
722
b4161d10 723 if (type == T_SRV || type == T_TLSA)
059ec3d9
PH
724 {
725 while (*checkname++ != '.');
726 while (*checkname++ != '.');
727 }
728
1dc92d5a 729 if (pcre_exec(regex_check_dns_names, NULL, CCS checkname, Ustrlen(checkname),
059ec3d9
PH
730 0, PCRE_EOPT, ovector, sizeof(ovector)/sizeof(int)) < 0)
731 {
732 DEBUG(D_dns)
733 debug_printf("DNS name syntax check failed: %s (%s)\n", name,
734 dns_text_type(type));
735 host_find_failed_syntax = TRUE;
736 return DNS_NOMATCH;
737 }
738 }
739
740#endif /* STAND_ALONE */
741
742/* Call the resolver; for an overlong response, res_search() will return the
bef5a11f
PH
743number of bytes the message would need, so we need to check for this case. The
744effect is to truncate overlong data.
745
30e18802
PH
746On some systems, res_search() will recognize "A-for-A" queries and return
747the IP address instead of returning -1 with h_error=HOST_NOT_FOUND. Some
748nameservers are also believed to do this. It is, of course, contrary to the
749specification of the DNS, so we lock it out. */
750
cc00f4af 751if ((type == T_A || type == T_AAAA) && string_is_ip_address(name, NULL) != 0)
30e18802
PH
752 return DNS_NOMATCH;
753
754/* If we are running in the test harness, instead of calling the normal resolver
bef5a11f
PH
755(res_search), we call fakens_search(), which recognizes certain special
756domains, and interfaces to a fake nameserver for certain special zones. */
757
cc00f4af
JH
758dnsa->answerlen = running_in_test_harness
759 ? fakens_search(name, type, dnsa->answer, MAXPACKET)
760 : res_search(CCS name, C_IN, type, dnsa->answer, MAXPACKET);
059ec3d9 761
80a47a2c
TK
762if (dnsa->answerlen > MAXPACKET)
763 {
764 DEBUG(D_dns) debug_printf("DNS lookup of %s (%s) resulted in overlong packet (size %d), truncating to %d.\n",
765 name, dns_text_type(type), dnsa->answerlen, MAXPACKET);
766 dnsa->answerlen = MAXPACKET;
767 }
059ec3d9
PH
768
769if (dnsa->answerlen < 0) switch (h_errno)
770 {
771 case HOST_NOT_FOUND:
772 DEBUG(D_dns) debug_printf("DNS lookup of %s (%s) gave HOST_NOT_FOUND\n"
773 "returning DNS_NOMATCH\n", name, dns_text_type(type));
774 return dns_return(name, type, DNS_NOMATCH);
775
776 case TRY_AGAIN:
777 DEBUG(D_dns) debug_printf("DNS lookup of %s (%s) gave TRY_AGAIN\n",
778 name, dns_text_type(type));
779
780 /* Cut this out for various test programs */
1dc92d5a 781#ifndef STAND_ALONE
55414b25 782 save_domain = deliver_domain;
1dc92d5a 783 deliver_domain = string_copy(name); /* set $domain */
55414b25 784 rc = match_isinlist(name, (const uschar **)&dns_again_means_nonexist, 0, NULL, NULL,
059ec3d9 785 MCL_DOMAIN, TRUE, NULL);
55414b25 786 deliver_domain = save_domain;
059ec3d9
PH
787 if (rc != OK)
788 {
789 DEBUG(D_dns) debug_printf("returning DNS_AGAIN\n");
790 return dns_return(name, type, DNS_AGAIN);
791 }
792 DEBUG(D_dns) debug_printf("%s is in dns_again_means_nonexist: returning "
793 "DNS_NOMATCH\n", name);
794 return dns_return(name, type, DNS_NOMATCH);
795
1dc92d5a 796#else /* For stand-alone tests */
059ec3d9 797 return dns_return(name, type, DNS_AGAIN);
1dc92d5a 798#endif
059ec3d9
PH
799
800 case NO_RECOVERY:
801 DEBUG(D_dns) debug_printf("DNS lookup of %s (%s) gave NO_RECOVERY\n"
802 "returning DNS_FAIL\n", name, dns_text_type(type));
803 return dns_return(name, type, DNS_FAIL);
804
805 case NO_DATA:
806 DEBUG(D_dns) debug_printf("DNS lookup of %s (%s) gave NO_DATA\n"
807 "returning DNS_NODATA\n", name, dns_text_type(type));
808 return dns_return(name, type, DNS_NODATA);
809
810 default:
811 DEBUG(D_dns) debug_printf("DNS lookup of %s (%s) gave unknown DNS error %d\n"
812 "returning DNS_FAIL\n", name, dns_text_type(type), h_errno);
813 return dns_return(name, type, DNS_FAIL);
814 }
815
816DEBUG(D_dns) debug_printf("DNS lookup of %s (%s) succeeded\n",
817 name, dns_text_type(type));
818
819return DNS_SUCCEED;
820}
821
822
823
824
825/************************************************
826* Do a DNS lookup and handle CNAMES *
827************************************************/
828
829/* Look up the given domain name, using the given type. Follow CNAMEs if
830necessary, but only so many times. There aren't supposed to be CNAME chains in
831the DNS, but you are supposed to cope with them if you find them.
832
833The assumption is made that if the resolver gives back records of the
834requested type *and* a CNAME, we don't need to make another call to look up
835the CNAME. I can't see how it could return only some of the right records. If
836it's done a CNAME lookup in the past, it will have all of them; if not, it
837won't return any.
838
839If fully_qualified_name is not NULL, set it to point to the full name
840returned by the resolver, if this is different to what it is given, unless
841the returned name starts with "*" as some nameservers seem to be returning
766e7a65
JH
842wildcards in this form. In international mode "different" means "alabel
843forms are different".
059ec3d9
PH
844
845Arguments:
846 dnsa pointer to dns_answer structure
847 name domain name to look up
848 type DNS record type (T_A, T_MX, etc)
849 fully_qualified_name if not NULL, return the returned name here if its
850 contents are different (i.e. it must be preset)
851
852Returns: DNS_SUCCEED successful lookup
853 DNS_NOMATCH name not found
854 DNS_NODATA no data found
855 DNS_AGAIN soft failure, try again later
856 DNS_FAIL DNS failure
857*/
858
859int
1dc92d5a 860dns_lookup(dns_answer *dnsa, const uschar *name, int type,
55414b25 861 const uschar **fully_qualified_name)
059ec3d9
PH
862{
863int i;
1dc92d5a 864const uschar *orig_name = name;
c85b3043 865BOOL secure_so_far = TRUE;
059ec3d9
PH
866
867/* Loop to follow CNAME chains so far, but no further... */
868
869for (i = 0; i < 10; i++)
870 {
806c3df9 871 uschar * data;
059ec3d9
PH
872 dns_record *rr, cname_rr, type_rr;
873 dns_scan dnss;
874 int datalen, rc;
875
876 /* DNS lookup failures get passed straight back. */
877
878 if ((rc = dns_basic_lookup(dnsa, name, type)) != DNS_SUCCEED) return rc;
879
880 /* We should have either records of the required type, or a CNAME record,
881 or both. We need to know whether both exist for getting the fully qualified
882 name, but avoid scanning more than necessary. Note that we must copy the
883 contents of any rr blocks returned by dns_next_rr() as they use the same
884 area in the dnsa block. */
885
886 cname_rr.data = type_rr.data = NULL;
887 for (rr = dns_next_rr(dnsa, &dnss, RESET_ANSWERS);
1705dd20 888 rr;
059ec3d9
PH
889 rr = dns_next_rr(dnsa, &dnss, RESET_NEXT))
890 {
891 if (rr->type == type)
892 {
893 if (type_rr.data == NULL) type_rr = *rr;
894 if (cname_rr.data != NULL) break;
895 }
896 else if (rr->type == T_CNAME) cname_rr = *rr;
897 }
898
a2042e78
PH
899 /* For the first time round this loop, if a CNAME was found, take the fully
900 qualified name from it; otherwise from the first data record, if present. */
059ec3d9 901
a2042e78 902 if (i == 0 && fully_qualified_name != NULL)
059ec3d9 903 {
766e7a65
JH
904 uschar * rr_name = cname_rr.data ? cname_rr.name
905 : type_rr.data ? type_rr.name : NULL;
906 if ( rr_name
907 && Ustrcmp(rr_name, *fully_qualified_name) != 0
908 && rr_name[0] != '*'
8c5d388a 909#ifdef SUPPORT_I18N
766e7a65
JH
910 && ( !string_is_utf8(*fully_qualified_name)
911 || Ustrcmp(rr_name,
912 string_domain_utf8_to_alabel(*fully_qualified_name, NULL)) != 0
913 )
914#endif
915 )
916 *fully_qualified_name = string_copy_dnsdomain(rr_name);
059ec3d9
PH
917 }
918
919 /* If any data records of the correct type were found, we are done. */
920
806c3df9 921 if (type_rr.data)
c85b3043
JH
922 {
923 if (!secure_so_far) /* mark insecure if any element of CNAME chain was */
4a142059 924 dns_set_insecure(dnsa);
c85b3043
JH
925 return DNS_SUCCEED;
926 }
059ec3d9
PH
927
928 /* If there are no data records, we need to re-scan the DNS using the
929 domain given in the CNAME record, which should exist (otherwise we should
930 have had a failure from dns_lookup). However code against the possibility of
931 its not existing. */
932
806c3df9
JH
933 if (!cname_rr.data)
934 return DNS_FAIL;
935
936 data = store_get(256);
059ec3d9 937 datalen = dn_expand(dnsa->answer, dnsa->answer + dnsa->answerlen,
806c3df9
JH
938 cname_rr.data, (DN_EXPAND_ARG4_TYPE)data, 256);
939 if (datalen < 0)
940 return DNS_FAIL;
059ec3d9 941 name = data;
a2042e78 942
c85b3043
JH
943 if (!dns_is_secure(dnsa))
944 secure_so_far = FALSE;
945
a2042e78 946 DEBUG(D_dns) debug_printf("CNAME found: change to %s\n", name);
059ec3d9
PH
947 } /* Loop back to do another lookup */
948
949/*Control reaches here after 10 times round the CNAME loop. Something isn't
950right... */
951
952log_write(0, LOG_MAIN, "CNAME loop for %s encountered", orig_name);
953return DNS_FAIL;
954}
955
956
957
33397d19
PH
958
959
960
961/************************************************
962* Do a DNS lookup and handle virtual types *
963************************************************/
964
9820a77f 965/* This function handles some invented "lookup types" that synthesize features
8e669ac1 966not available in the basic types. The special types all have negative values.
33397d19
PH
967Positive type values are passed straight on to dns_lookup().
968
969Arguments:
970 dnsa pointer to dns_answer structure
971 name domain name to look up
972 type DNS record type (T_A, T_MX, etc or a "special")
973 fully_qualified_name if not NULL, return the returned name here if its
974 contents are different (i.e. it must be preset)
975
976Returns: DNS_SUCCEED successful lookup
977 DNS_NOMATCH name not found
978 DNS_NODATA no data found
979 DNS_AGAIN soft failure, try again later
980 DNS_FAIL DNS failure
981*/
982
983int
1dc92d5a 984dns_special_lookup(dns_answer *dnsa, const uschar *name, int type,
55414b25 985 const uschar **fully_qualified_name)
33397d19 986{
d2a2c69b 987switch (type)
e5a9dba6 988 {
d2a2c69b
JH
989 /* The "mx hosts only" type doesn't require any special action here */
990 case T_MXH:
1705dd20 991 return dns_lookup(dnsa, name, T_MX, fully_qualified_name);
d2a2c69b
JH
992
993 /* Find nameservers for the domain or the nearest enclosing zone, excluding
994 the root servers. */
995 case T_ZNS:
1705dd20
JH
996 type = T_NS;
997 /* FALLTHROUGH */
d2a2c69b 998 case T_SOA:
1705dd20
JH
999 {
1000 const uschar *d = name;
1001 while (d != 0)
1002 {
1003 int rc = dns_lookup(dnsa, d, type, fully_qualified_name);
1004 if (rc != DNS_NOMATCH && rc != DNS_NODATA) return rc;
1005 while (*d != 0 && *d != '.') d++;
1006 if (*d++ == 0) break;
1007 }
1008 return DNS_NOMATCH;
1009 }
d2a2c69b
JH
1010
1011 /* Try to look up the Client SMTP Authorization SRV record for the name. If
1012 there isn't one, search from the top downwards for a CSA record in a parent
1013 domain, which might be making assertions about subdomains. If we find a record
1014 we set fully_qualified_name to whichever lookup succeeded, so that the caller
1015 can tell whether to look at the explicit authorization field or the subdomain
1016 assertion field. */
1017 case T_CSA:
1705dd20
JH
1018 {
1019 uschar *srvname, *namesuff, *tld, *p;
1020 int priority, weight, port;
1021 int limit, rc, i;
1022 BOOL ipv6;
1023 dns_record *rr;
1024 dns_scan dnss;
1025
1026 DEBUG(D_dns) debug_printf("CSA lookup of %s\n", name);
1027
1028 srvname = string_sprintf("_client._smtp.%s", name);
1029 rc = dns_lookup(dnsa, srvname, T_SRV, NULL);
1030 if (rc == DNS_SUCCEED || rc == DNS_AGAIN)
1031 {
1032 if (rc == DNS_SUCCEED) *fully_qualified_name = string_copy(name);
1033 return rc;
1034 }
d2a2c69b 1035
1705dd20
JH
1036 /* Search for CSA subdomain assertion SRV records from the top downwards,
1037 starting with the 2nd level domain. This order maximizes cache-friendliness.
1038 We skip the top level domains to avoid loading their nameservers and because
1039 we know they'll never have CSA SRV records. */
d2a2c69b 1040
1705dd20
JH
1041 namesuff = Ustrrchr(name, '.');
1042 if (namesuff == NULL) return DNS_NOMATCH;
1043 tld = namesuff + 1;
1044 ipv6 = FALSE;
1045 limit = dns_csa_search_limit;
1046
1047 /* Use more appropriate search parameters if we are in the reverse DNS. */
1048
1049 if (strcmpic(namesuff, US".arpa") == 0)
1050 if (namesuff - 8 > name && strcmpic(namesuff - 8, US".in-addr.arpa") == 0)
1051 {
1052 namesuff -= 8;
d2a2c69b 1053 tld = namesuff + 1;
1705dd20
JH
1054 limit = 3;
1055 }
1056 else if (namesuff - 4 > name && strcmpic(namesuff - 4, US".ip6.arpa") == 0)
1057 {
1058 namesuff -= 4;
1059 tld = namesuff + 1;
1060 ipv6 = TRUE;
1061 limit = 3;
1062 }
d2a2c69b 1063
1705dd20 1064 DEBUG(D_dns) debug_printf("CSA TLD %s\n", tld);
d2a2c69b 1065
1705dd20
JH
1066 /* Do not perform the search if the top level or 2nd level domains do not
1067 exist. This is quite common, and when it occurs all the search queries would
1068 go to the root or TLD name servers, which is not friendly. So we check the
1069 AUTHORITY section; if it contains the root's SOA record or the TLD's SOA then
1070 the TLD or the 2LD (respectively) doesn't exist and we can skip the search.
1071 If the TLD and the 2LD exist but the explicit CSA record lookup failed, then
1072 the AUTHORITY SOA will be the 2LD's or a subdomain thereof. */
1073
1074 if (rc == DNS_NOMATCH)
1075 {
1076 /* This is really gross. The successful return value from res_search() is
1077 the packet length, which is stored in dnsa->answerlen. If we get a
1078 negative DNS reply then res_search() returns -1, which causes the bounds
1079 checks for name decompression to fail when it is treated as a packet
1080 length, which in turn causes the authority search to fail. The correct
1081 packet length has been lost inside libresolv, so we have to guess a
1082 replacement value. (The only way to fix this properly would be to
1083 re-implement res_search() and res_query() so that they don't muddle their
1084 success and packet length return values.) For added safety we only reset
1085 the packet length if the packet header looks plausible. */
1086
1087 HEADER *h = (HEADER *)dnsa->answer;
1088 if (h->qr == 1 && h->opcode == QUERY && h->tc == 0
1089 && (h->rcode == NOERROR || h->rcode == NXDOMAIN)
1090 && ntohs(h->qdcount) == 1 && ntohs(h->ancount) == 0
1091 && ntohs(h->nscount) >= 1)
1092 dnsa->answerlen = MAXPACKET;
1093
1094 for (rr = dns_next_rr(dnsa, &dnss, RESET_AUTHORITY);
1095 rr;
1096 rr = dns_next_rr(dnsa, &dnss, RESET_NEXT)
1097 )
1098 if (rr->type != T_SOA) continue;
1099 else if (strcmpic(rr->name, US"") == 0 ||
1100 strcmpic(rr->name, tld) == 0) return DNS_NOMATCH;
1101 else break;
1102 }
d2a2c69b 1103
1705dd20
JH
1104 for (i = 0; i < limit; i++)
1105 {
1106 if (ipv6)
1107 {
1108 /* Scan through the IPv6 reverse DNS in chunks of 16 bits worth of IP
1109 address, i.e. 4 hex chars and 4 dots, i.e. 8 chars. */
1110 namesuff -= 8;
1111 if (namesuff <= name) return DNS_NOMATCH;
1112 }
1113 else
1114 /* Find the start of the preceding domain name label. */
1115 do
1116 if (--namesuff <= name) return DNS_NOMATCH;
1117 while (*namesuff != '.');
1118
1119 DEBUG(D_dns) debug_printf("CSA parent search at %s\n", namesuff + 1);
1120
1121 srvname = string_sprintf("_client._smtp.%s", namesuff + 1);
1122 rc = dns_lookup(dnsa, srvname, T_SRV, NULL);
1123 if (rc == DNS_AGAIN) return rc;
1124 if (rc != DNS_SUCCEED) continue;
1125
1126 /* Check that the SRV record we have found is worth returning. We don't
1127 just return the first one we find, because some lower level SRV record
1128 might make stricter assertions than its parent domain. */
1129
1130 for (rr = dns_next_rr(dnsa, &dnss, RESET_ANSWERS);
1131 rr;
1132 rr = dns_next_rr(dnsa, &dnss, RESET_NEXT))
1133 {
1134 if (rr->type != T_SRV) continue;
d2a2c69b 1135
1705dd20
JH
1136 /* Extract the numerical SRV fields (p is incremented) */
1137 p = rr->data;
1138 GETSHORT(priority, p);
1139 GETSHORT(weight, p); weight = weight; /* compiler quietening */
1140 GETSHORT(port, p);
d2a2c69b 1141
1705dd20
JH
1142 /* Check the CSA version number */
1143 if (priority != 1) continue;
d2a2c69b 1144
1705dd20
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1145 /* If it's making an interesting assertion, return this response. */
1146 if (port & 1)
d2a2c69b 1147 {
1705dd20
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1148 *fully_qualified_name = namesuff + 1;
1149 return DNS_SUCCEED;
d2a2c69b 1150 }
d2a2c69b 1151 }
1705dd20
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1152 }
1153 return DNS_NOMATCH;
1154 }
e5a9dba6 1155
d2a2c69b 1156 default:
1705dd20
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1157 if (type >= 0)
1158 return dns_lookup(dnsa, name, type, fully_qualified_name);
e5a9dba6
PH
1159 }
1160
33397d19
PH
1161/* Control should never reach here */
1162
1163return DNS_FAIL;
1164}
1165
1166
1167
059ec3d9
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1168
1169
1170/*************************************************
1171* Get address(es) from DNS record *
1172*************************************************/
1173
d57d474f 1174/* The record type is either T_A for an IPv4 address or T_AAAA for an IPv6 address.
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1175
1176Argument:
1177 dnsa the DNS answer block
1178 rr the RR
1179
e1a3f32f 1180Returns: pointer to a chain of dns_address items; NULL when the dnsa was overrun
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1181*/
1182
1183dns_address *
1184dns_address_from_rr(dns_answer *dnsa, dns_record *rr)
1185{
e1a3f32f
JH
1186dns_address * yield = NULL;
1187uschar * dnsa_lim = dnsa->answer + dnsa->answerlen;
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1188
1189if (rr->type == T_A)
1190 {
d2a2c69b 1191 uschar *p = US rr->data;
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1192 if (p + 4 <= dnsa_lim)
1193 {
1194 yield = store_get(sizeof(dns_address) + 20);
1195 (void)sprintf(CS yield->address, "%d.%d.%d.%d", p[0], p[1], p[2], p[3]);
1196 yield->next = NULL;
1197 }
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1198 }
1199
1200#if HAVE_IPV6
1201
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1202else
1203 {
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1204 if (rr->data + 16 <= dnsa_lim)
1205 {
d57d474f
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1206 struct in6_addr in6;
1207 int i;
f794c12b 1208 for (i = 0; i < 16; i++) in6.s6_addr[i] = rr->data[i];
e1a3f32f 1209 yield = store_get(sizeof(dns_address) + 50);
d57d474f 1210 inet_ntop(AF_INET6, &in6, CS yield->address, 50);
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1211 yield->next = NULL;
1212 }
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1213 }
1214#endif /* HAVE_IPV6 */
1215
1216return yield;
1217}
1218
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1219
1220
1221void
1222dns_pattern_init(void)
1223{
1224if (check_dns_names_pattern[0] != 0 && !regex_check_dns_names)
1225 regex_check_dns_names =
1226 regex_must_compile(check_dns_names_pattern, FALSE, TRUE);
1227}
1228
8c51eead
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1229/* vi: aw ai sw=2
1230*/
059ec3d9 1231/* End of dns.c */