constification
[exim.git] / src / src / dns.c
CommitLineData
059ec3d9
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1/*************************************************
2* Exim - an Internet mail transport agent *
3*************************************************/
4
80fea873 5/* Copyright (c) University of Cambridge 1995 - 2016 */
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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
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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
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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.
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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.
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28
29Arguments:
e7726cbf 30 domain the domain name
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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];
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44uschar utilname[256];
45uschar *aptr = answerptr; /* Locally modified */
46struct stat statbuf;
47
48/* Remove terminating dot. */
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49
50if (domain[len - 1] == '.') len--;
51Ustrncpy(name, domain, len);
52name[len] = 0;
bef5a11f 53
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54/* Look for the fakens utility, and if it exists, call it. */
55
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HSHR
56(void)string_format(utilname, sizeof(utilname), "%s/bin/fakens",
57 config_main_directory);
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58
59if (stat(CS utilname, &statbuf) >= 0)
bef5a11f 60 {
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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));
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66
67 argv[0] = utilname;
5f3d0983 68 argv[1] = config_main_directory;
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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
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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 {
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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");
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108 }
109 }
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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);
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118
119return res_search(CS domain, C_IN, type, answerptr, size);
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120}
121
122
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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
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135
136Returns: nothing
137*/
138
139void
8c51eead 140dns_init(BOOL qualify_single, BOOL search_parents, BOOL use_dnssec)
059ec3d9 141{
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PP
142res_state resp = os_get_dns_resolver_res();
143
144if ((resp->options & RES_INIT) == 0)
059ec3d9 145 {
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PP
146 DEBUG(D_resolver) resp->options |= RES_DEBUG; /* For Cygwin */
147 os_put_dns_resolver_res(resp);
059ec3d9 148 res_init();
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PP
149 DEBUG(D_resolver) resp->options |= RES_DEBUG;
150 os_put_dns_resolver_res(resp);
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PH
151 }
152
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PP
153resp->options &= ~(RES_DNSRCH | RES_DEFNAMES);
154resp->options |= (qualify_single? RES_DEFNAMES : 0) |
059ec3d9 155 (search_parents? RES_DNSRCH : 0);
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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");
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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
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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
dd708fd7 312dnss_inc_aptr(const dns_answer * dnsa, dns_scan * dnss, unsigned delta)
2a407b17
JH
313{
314return (dnss->aptr += delta) >= dnsa->answer + dnsa->answerlen;
315}
316
059ec3d9
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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
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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 *
dd708fd7 335dns_next_rr(const dns_answer *dnsa, dns_scan *dnss, int reset)
059ec3d9 336{
dd708fd7 337const HEADER * h = (const HEADER *)dnsa->answer;
059ec3d9
PH
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";
dd708fd7 366 if (dnss_inc_aptr(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";
dd708fd7 395 if (dnss_inc_aptr(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";
dd708fd7 399 if (dnss_inc_aptr(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 425TRACE trace = "R-name";
dd708fd7 426if (dnss_inc_aptr(dnsa, dnss, namelen)) goto null_return;
2a407b17
JH
427
428GETSHORT(dnss->srr.type, dnss->aptr); /* Record type */
429TRACE trace = "R-class";
dd708fd7 430if (dnss_inc_aptr(dnsa, dnss, 2)) goto null_return; /* Don't want class */
2a407b17
JH
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;
dd708fd7 469const HEADER * h = (const HEADER *) dnsa->answer;
09b80b4e
JH
470
471if (!h->nscount || !h->aa) return NULL;
dd708fd7 472for (rr = dns_next_rr(dnsa, &dnss, RESET_AUTHORITY);
09b80b4e 473 rr;
dd708fd7 474 rr = dns_next_rr(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
dd708fd7 502const HEADER * h = (const HEADER *) dnsa->answer;
09b80b4e
JH
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
dd708fd7 553return ((const 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);
4b0fe319 666if ((previous = tree_search(tree_dns_fails, node_name)))
059ec3d9
PH
667 {
668 DEBUG(D_dns) debug_printf("DNS lookup of %.255s-%s: using cached value %s\n",
669 name, dns_text_type(type),
670 (previous->data.val == DNS_NOMATCH)? "DNS_NOMATCH" :
671 (previous->data.val == DNS_NODATA)? "DNS_NODATA" :
672 (previous->data.val == DNS_AGAIN)? "DNS_AGAIN" :
673 (previous->data.val == DNS_FAIL)? "DNS_FAIL" : "??");
674 return previous->data.val;
675 }
676
8c5d388a 677#ifdef SUPPORT_I18N
9d4319df
JH
678/* Convert all names to a-label form before doing lookup */
679 {
680 uschar * alabel;
681 uschar * errstr = NULL;
766e7a65
JH
682 DEBUG(D_dns) if (string_is_utf8(name))
683 debug_printf("convert utf8 '%s' to alabel for for lookup\n", name);
9d4319df
JH
684 if ((alabel = string_domain_utf8_to_alabel(name, &errstr)), errstr)
685 {
686 DEBUG(D_dns)
37bf366e 687 debug_printf("DNS name '%s' utf8 conversion to alabel failed: %s\n", name,
9d4319df
JH
688 errstr);
689 host_find_failed_syntax = TRUE;
690 return DNS_NOMATCH;
691 }
692 name = alabel;
693 }
694#endif
695
059ec3d9
PH
696/* If configured, check the hygene of the name passed to lookup. Otherwise,
697although DNS lookups may give REFUSED at the lower level, some resolvers
698turn this into TRY_AGAIN, which is silly. Give a NOMATCH return, since such
699domains cannot be in the DNS. The check is now done by a regular expression;
700give it space for substring storage to save it having to get its own if the
701regex has substrings that are used - the default uses a conditional.
702
703This test is omitted for PTR records. These occur only in calls from the dnsdb
704lookup, which constructs the names itself, so they should be OK. Besides,
705bitstring labels don't conform to normal name syntax. (But the aren't used any
706more.)
707
708For SRV records, we omit the initial _smtp._tcp. components at the start. */
709
710#ifndef STAND_ALONE /* Omit this for stand-alone tests */
711
482d1455 712if (check_dns_names_pattern[0] != 0 && type != T_PTR && type != T_TXT)
059ec3d9 713 {
1dc92d5a 714 const uschar *checkname = name;
059ec3d9
PH
715 int ovector[3*(EXPAND_MAXN+1)];
716
476be7e2 717 dns_pattern_init();
059ec3d9
PH
718
719 /* For an SRV lookup, skip over the first two components (the service and
720 protocol names, which both start with an underscore). */
721
b4161d10 722 if (type == T_SRV || type == T_TLSA)
059ec3d9
PH
723 {
724 while (*checkname++ != '.');
725 while (*checkname++ != '.');
726 }
727
1dc92d5a 728 if (pcre_exec(regex_check_dns_names, NULL, CCS checkname, Ustrlen(checkname),
059ec3d9
PH
729 0, PCRE_EOPT, ovector, sizeof(ovector)/sizeof(int)) < 0)
730 {
731 DEBUG(D_dns)
732 debug_printf("DNS name syntax check failed: %s (%s)\n", name,
733 dns_text_type(type));
734 host_find_failed_syntax = TRUE;
735 return DNS_NOMATCH;
736 }
737 }
738
739#endif /* STAND_ALONE */
740
741/* Call the resolver; for an overlong response, res_search() will return the
bef5a11f
PH
742number of bytes the message would need, so we need to check for this case. The
743effect is to truncate overlong data.
744
30e18802
PH
745On some systems, res_search() will recognize "A-for-A" queries and return
746the IP address instead of returning -1 with h_error=HOST_NOT_FOUND. Some
747nameservers are also believed to do this. It is, of course, contrary to the
748specification of the DNS, so we lock it out. */
749
cc00f4af 750if ((type == T_A || type == T_AAAA) && string_is_ip_address(name, NULL) != 0)
30e18802
PH
751 return DNS_NOMATCH;
752
753/* If we are running in the test harness, instead of calling the normal resolver
bef5a11f
PH
754(res_search), we call fakens_search(), which recognizes certain special
755domains, and interfaces to a fake nameserver for certain special zones. */
756
cc00f4af
JH
757dnsa->answerlen = running_in_test_harness
758 ? fakens_search(name, type, dnsa->answer, MAXPACKET)
759 : res_search(CCS name, C_IN, type, dnsa->answer, MAXPACKET);
059ec3d9 760
80a47a2c
TK
761if (dnsa->answerlen > MAXPACKET)
762 {
763 DEBUG(D_dns) debug_printf("DNS lookup of %s (%s) resulted in overlong packet (size %d), truncating to %d.\n",
764 name, dns_text_type(type), dnsa->answerlen, MAXPACKET);
765 dnsa->answerlen = MAXPACKET;
766 }
059ec3d9
PH
767
768if (dnsa->answerlen < 0) switch (h_errno)
769 {
770 case HOST_NOT_FOUND:
4b0fe319
JH
771 DEBUG(D_dns) debug_printf("DNS lookup of %s (%s) gave HOST_NOT_FOUND\n"
772 "returning DNS_NOMATCH\n", name, dns_text_type(type));
773 return dns_return(name, type, DNS_NOMATCH);
059ec3d9
PH
774
775 case TRY_AGAIN:
4b0fe319
JH
776 DEBUG(D_dns) debug_printf("DNS lookup of %s (%s) gave TRY_AGAIN\n",
777 name, dns_text_type(type));
059ec3d9 778
4b0fe319 779 /* Cut this out for various test programs */
1dc92d5a 780#ifndef STAND_ALONE
4b0fe319
JH
781 save_domain = deliver_domain;
782 deliver_domain = string_copy(name); /* set $domain */
783 rc = match_isinlist(name, (const uschar **)&dns_again_means_nonexist, 0, NULL, NULL,
784 MCL_DOMAIN, TRUE, NULL);
785 deliver_domain = save_domain;
786 if (rc != OK)
787 {
788 DEBUG(D_dns) debug_printf("returning DNS_AGAIN\n");
789 return dns_return(name, type, DNS_AGAIN);
790 }
791 DEBUG(D_dns) debug_printf("%s is in dns_again_means_nonexist: returning "
792 "DNS_NOMATCH\n", name);
793 return dns_return(name, type, DNS_NOMATCH);
059ec3d9 794
1dc92d5a 795#else /* For stand-alone tests */
4b0fe319 796 return dns_return(name, type, DNS_AGAIN);
1dc92d5a 797#endif
059ec3d9
PH
798
799 case NO_RECOVERY:
4b0fe319
JH
800 DEBUG(D_dns) debug_printf("DNS lookup of %s (%s) gave NO_RECOVERY\n"
801 "returning DNS_FAIL\n", name, dns_text_type(type));
802 return dns_return(name, type, DNS_FAIL);
059ec3d9
PH
803
804 case NO_DATA:
4b0fe319
JH
805 DEBUG(D_dns) debug_printf("DNS lookup of %s (%s) gave NO_DATA\n"
806 "returning DNS_NODATA\n", name, dns_text_type(type));
807 return dns_return(name, type, DNS_NODATA);
059ec3d9
PH
808
809 default:
4b0fe319
JH
810 DEBUG(D_dns) debug_printf("DNS lookup of %s (%s) gave unknown DNS error %d\n"
811 "returning DNS_FAIL\n", name, dns_text_type(type), h_errno);
812 return dns_return(name, type, DNS_FAIL);
059ec3d9
PH
813 }
814
815DEBUG(D_dns) debug_printf("DNS lookup of %s (%s) succeeded\n",
816 name, dns_text_type(type));
817
818return DNS_SUCCEED;
819}
820
821
822
823
824/************************************************
825* Do a DNS lookup and handle CNAMES *
826************************************************/
827
828/* Look up the given domain name, using the given type. Follow CNAMEs if
829necessary, but only so many times. There aren't supposed to be CNAME chains in
830the DNS, but you are supposed to cope with them if you find them.
831
832The assumption is made that if the resolver gives back records of the
833requested type *and* a CNAME, we don't need to make another call to look up
834the CNAME. I can't see how it could return only some of the right records. If
835it's done a CNAME lookup in the past, it will have all of them; if not, it
836won't return any.
837
838If fully_qualified_name is not NULL, set it to point to the full name
839returned by the resolver, if this is different to what it is given, unless
840the returned name starts with "*" as some nameservers seem to be returning
766e7a65
JH
841wildcards in this form. In international mode "different" means "alabel
842forms are different".
059ec3d9
PH
843
844Arguments:
845 dnsa pointer to dns_answer structure
846 name domain name to look up
847 type DNS record type (T_A, T_MX, etc)
848 fully_qualified_name if not NULL, return the returned name here if its
849 contents are different (i.e. it must be preset)
850
851Returns: DNS_SUCCEED successful lookup
852 DNS_NOMATCH name not found
853 DNS_NODATA no data found
854 DNS_AGAIN soft failure, try again later
855 DNS_FAIL DNS failure
856*/
857
858int
1dc92d5a 859dns_lookup(dns_answer *dnsa, const uschar *name, int type,
55414b25 860 const uschar **fully_qualified_name)
059ec3d9
PH
861{
862int i;
1dc92d5a 863const uschar *orig_name = name;
c85b3043 864BOOL secure_so_far = TRUE;
059ec3d9
PH
865
866/* Loop to follow CNAME chains so far, but no further... */
867
868for (i = 0; i < 10; i++)
869 {
806c3df9 870 uschar * data;
059ec3d9
PH
871 dns_record *rr, cname_rr, type_rr;
872 dns_scan dnss;
873 int datalen, rc;
874
875 /* DNS lookup failures get passed straight back. */
876
dd708fd7
JH
877 if ((rc = dns_basic_lookup(dnsa, name, type)) != DNS_SUCCEED)
878 return rc;
059ec3d9
PH
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 889 rr = dns_next_rr(dnsa, &dnss, RESET_NEXT))
059ec3d9
PH
890 if (rr->type == type)
891 {
892 if (type_rr.data == NULL) type_rr = *rr;
893 if (cname_rr.data != NULL) break;
894 }
dd708fd7
JH
895 else if (rr->type == T_CNAME)
896 cname_rr = *rr;
059ec3d9 897
a2042e78
PH
898 /* For the first time round this loop, if a CNAME was found, take the fully
899 qualified name from it; otherwise from the first data record, if present. */
059ec3d9 900
dd708fd7 901 if (i == 0 && fully_qualified_name)
059ec3d9 902 {
dd708fd7
JH
903 uschar * rr_name = cname_rr.data
904 ? cname_rr.name : type_rr.data ? type_rr.name : NULL;
766e7a65
JH
905 if ( rr_name
906 && Ustrcmp(rr_name, *fully_qualified_name) != 0
907 && rr_name[0] != '*'
8c5d388a 908#ifdef SUPPORT_I18N
766e7a65
JH
909 && ( !string_is_utf8(*fully_qualified_name)
910 || Ustrcmp(rr_name,
911 string_domain_utf8_to_alabel(*fully_qualified_name, NULL)) != 0
912 )
913#endif
914 )
915 *fully_qualified_name = string_copy_dnsdomain(rr_name);
059ec3d9
PH
916 }
917
918 /* If any data records of the correct type were found, we are done. */
919
806c3df9 920 if (type_rr.data)
c85b3043
JH
921 {
922 if (!secure_so_far) /* mark insecure if any element of CNAME chain was */
4a142059 923 dns_set_insecure(dnsa);
c85b3043
JH
924 return DNS_SUCCEED;
925 }
059ec3d9
PH
926
927 /* If there are no data records, we need to re-scan the DNS using the
928 domain given in the CNAME record, which should exist (otherwise we should
929 have had a failure from dns_lookup). However code against the possibility of
930 its not existing. */
931
806c3df9
JH
932 if (!cname_rr.data)
933 return DNS_FAIL;
934
935 data = store_get(256);
dd708fd7
JH
936 if ((datalen = dn_expand(dnsa->answer, dnsa->answer + dnsa->answerlen,
937 cname_rr.data, (DN_EXPAND_ARG4_TYPE)data, 256)) < 0)
806c3df9 938 return DNS_FAIL;
059ec3d9 939 name = data;
a2042e78 940
c85b3043
JH
941 if (!dns_is_secure(dnsa))
942 secure_so_far = FALSE;
943
a2042e78 944 DEBUG(D_dns) debug_printf("CNAME found: change to %s\n", name);
059ec3d9
PH
945 } /* Loop back to do another lookup */
946
947/*Control reaches here after 10 times round the CNAME loop. Something isn't
948right... */
949
950log_write(0, LOG_MAIN, "CNAME loop for %s encountered", orig_name);
951return DNS_FAIL;
952}
953
954
955
33397d19
PH
956
957
958
959/************************************************
960* Do a DNS lookup and handle virtual types *
961************************************************/
962
9820a77f 963/* This function handles some invented "lookup types" that synthesize features
8e669ac1 964not available in the basic types. The special types all have negative values.
33397d19
PH
965Positive type values are passed straight on to dns_lookup().
966
967Arguments:
968 dnsa pointer to dns_answer structure
969 name domain name to look up
970 type DNS record type (T_A, T_MX, etc or a "special")
971 fully_qualified_name if not NULL, return the returned name here if its
972 contents are different (i.e. it must be preset)
973
974Returns: DNS_SUCCEED successful lookup
975 DNS_NOMATCH name not found
976 DNS_NODATA no data found
977 DNS_AGAIN soft failure, try again later
978 DNS_FAIL DNS failure
979*/
980
981int
1dc92d5a 982dns_special_lookup(dns_answer *dnsa, const uschar *name, int type,
55414b25 983 const uschar **fully_qualified_name)
33397d19 984{
d2a2c69b 985switch (type)
e5a9dba6 986 {
d2a2c69b
JH
987 /* The "mx hosts only" type doesn't require any special action here */
988 case T_MXH:
1705dd20 989 return dns_lookup(dnsa, name, T_MX, fully_qualified_name);
d2a2c69b
JH
990
991 /* Find nameservers for the domain or the nearest enclosing zone, excluding
992 the root servers. */
993 case T_ZNS:
1705dd20
JH
994 type = T_NS;
995 /* FALLTHROUGH */
d2a2c69b 996 case T_SOA:
1705dd20
JH
997 {
998 const uschar *d = name;
999 while (d != 0)
1000 {
1001 int rc = dns_lookup(dnsa, d, type, fully_qualified_name);
1002 if (rc != DNS_NOMATCH && rc != DNS_NODATA) return rc;
1003 while (*d != 0 && *d != '.') d++;
1004 if (*d++ == 0) break;
1005 }
1006 return DNS_NOMATCH;
1007 }
d2a2c69b
JH
1008
1009 /* Try to look up the Client SMTP Authorization SRV record for the name. If
1010 there isn't one, search from the top downwards for a CSA record in a parent
1011 domain, which might be making assertions about subdomains. If we find a record
1012 we set fully_qualified_name to whichever lookup succeeded, so that the caller
1013 can tell whether to look at the explicit authorization field or the subdomain
1014 assertion field. */
1015 case T_CSA:
1705dd20
JH
1016 {
1017 uschar *srvname, *namesuff, *tld, *p;
1018 int priority, weight, port;
1019 int limit, rc, i;
1020 BOOL ipv6;
1021 dns_record *rr;
1022 dns_scan dnss;
1023
1024 DEBUG(D_dns) debug_printf("CSA lookup of %s\n", name);
1025
1026 srvname = string_sprintf("_client._smtp.%s", name);
1027 rc = dns_lookup(dnsa, srvname, T_SRV, NULL);
1028 if (rc == DNS_SUCCEED || rc == DNS_AGAIN)
1029 {
1030 if (rc == DNS_SUCCEED) *fully_qualified_name = string_copy(name);
1031 return rc;
1032 }
d2a2c69b 1033
1705dd20
JH
1034 /* Search for CSA subdomain assertion SRV records from the top downwards,
1035 starting with the 2nd level domain. This order maximizes cache-friendliness.
1036 We skip the top level domains to avoid loading their nameservers and because
1037 we know they'll never have CSA SRV records. */
d2a2c69b 1038
1705dd20
JH
1039 namesuff = Ustrrchr(name, '.');
1040 if (namesuff == NULL) return DNS_NOMATCH;
1041 tld = namesuff + 1;
1042 ipv6 = FALSE;
1043 limit = dns_csa_search_limit;
1044
1045 /* Use more appropriate search parameters if we are in the reverse DNS. */
1046
1047 if (strcmpic(namesuff, US".arpa") == 0)
1048 if (namesuff - 8 > name && strcmpic(namesuff - 8, US".in-addr.arpa") == 0)
1049 {
1050 namesuff -= 8;
d2a2c69b 1051 tld = namesuff + 1;
1705dd20
JH
1052 limit = 3;
1053 }
1054 else if (namesuff - 4 > name && strcmpic(namesuff - 4, US".ip6.arpa") == 0)
1055 {
1056 namesuff -= 4;
1057 tld = namesuff + 1;
1058 ipv6 = TRUE;
1059 limit = 3;
1060 }
d2a2c69b 1061
1705dd20 1062 DEBUG(D_dns) debug_printf("CSA TLD %s\n", tld);
d2a2c69b 1063
1705dd20
JH
1064 /* Do not perform the search if the top level or 2nd level domains do not
1065 exist. This is quite common, and when it occurs all the search queries would
1066 go to the root or TLD name servers, which is not friendly. So we check the
1067 AUTHORITY section; if it contains the root's SOA record or the TLD's SOA then
1068 the TLD or the 2LD (respectively) doesn't exist and we can skip the search.
1069 If the TLD and the 2LD exist but the explicit CSA record lookup failed, then
1070 the AUTHORITY SOA will be the 2LD's or a subdomain thereof. */
1071
1072 if (rc == DNS_NOMATCH)
1073 {
1074 /* This is really gross. The successful return value from res_search() is
1075 the packet length, which is stored in dnsa->answerlen. If we get a
1076 negative DNS reply then res_search() returns -1, which causes the bounds
1077 checks for name decompression to fail when it is treated as a packet
1078 length, which in turn causes the authority search to fail. The correct
1079 packet length has been lost inside libresolv, so we have to guess a
1080 replacement value. (The only way to fix this properly would be to
1081 re-implement res_search() and res_query() so that they don't muddle their
1082 success and packet length return values.) For added safety we only reset
1083 the packet length if the packet header looks plausible. */
1084
dd708fd7 1085 const HEADER * h = (const HEADER *)dnsa->answer;
1705dd20
JH
1086 if (h->qr == 1 && h->opcode == QUERY && h->tc == 0
1087 && (h->rcode == NOERROR || h->rcode == NXDOMAIN)
1088 && ntohs(h->qdcount) == 1 && ntohs(h->ancount) == 0
1089 && ntohs(h->nscount) >= 1)
1090 dnsa->answerlen = MAXPACKET;
1091
1092 for (rr = dns_next_rr(dnsa, &dnss, RESET_AUTHORITY);
1093 rr;
1094 rr = dns_next_rr(dnsa, &dnss, RESET_NEXT)
1095 )
1096 if (rr->type != T_SOA) continue;
1097 else if (strcmpic(rr->name, US"") == 0 ||
1098 strcmpic(rr->name, tld) == 0) return DNS_NOMATCH;
1099 else break;
1100 }
d2a2c69b 1101
1705dd20
JH
1102 for (i = 0; i < limit; i++)
1103 {
1104 if (ipv6)
1105 {
1106 /* Scan through the IPv6 reverse DNS in chunks of 16 bits worth of IP
1107 address, i.e. 4 hex chars and 4 dots, i.e. 8 chars. */
1108 namesuff -= 8;
1109 if (namesuff <= name) return DNS_NOMATCH;
1110 }
1111 else
1112 /* Find the start of the preceding domain name label. */
1113 do
1114 if (--namesuff <= name) return DNS_NOMATCH;
1115 while (*namesuff != '.');
1116
1117 DEBUG(D_dns) debug_printf("CSA parent search at %s\n", namesuff + 1);
1118
1119 srvname = string_sprintf("_client._smtp.%s", namesuff + 1);
1120 rc = dns_lookup(dnsa, srvname, T_SRV, NULL);
1121 if (rc == DNS_AGAIN) return rc;
1122 if (rc != DNS_SUCCEED) continue;
1123
1124 /* Check that the SRV record we have found is worth returning. We don't
1125 just return the first one we find, because some lower level SRV record
1126 might make stricter assertions than its parent domain. */
1127
1128 for (rr = dns_next_rr(dnsa, &dnss, RESET_ANSWERS);
1129 rr;
dd708fd7 1130 rr = dns_next_rr(dnsa, &dnss, RESET_NEXT)) if (rr->type == T_SRV)
1705dd20 1131 {
dd708fd7 1132 const uschar * p = rr->data;
d2a2c69b 1133
1705dd20 1134 /* Extract the numerical SRV fields (p is incremented) */
1705dd20
JH
1135 GETSHORT(priority, p);
1136 GETSHORT(weight, p); weight = weight; /* compiler quietening */
1137 GETSHORT(port, p);
d2a2c69b 1138
1705dd20
JH
1139 /* Check the CSA version number */
1140 if (priority != 1) continue;
d2a2c69b 1141
1705dd20
JH
1142 /* If it's making an interesting assertion, return this response. */
1143 if (port & 1)
d2a2c69b 1144 {
1705dd20
JH
1145 *fully_qualified_name = namesuff + 1;
1146 return DNS_SUCCEED;
d2a2c69b 1147 }
d2a2c69b 1148 }
1705dd20
JH
1149 }
1150 return DNS_NOMATCH;
1151 }
e5a9dba6 1152
d2a2c69b 1153 default:
1705dd20
JH
1154 if (type >= 0)
1155 return dns_lookup(dnsa, name, type, fully_qualified_name);
e5a9dba6
PH
1156 }
1157
33397d19
PH
1158/* Control should never reach here */
1159
1160return DNS_FAIL;
1161}
1162
1163
1164
059ec3d9
PH
1165
1166
1167/*************************************************
1168* Get address(es) from DNS record *
1169*************************************************/
1170
d57d474f 1171/* The record type is either T_A for an IPv4 address or T_AAAA for an IPv6 address.
059ec3d9
PH
1172
1173Argument:
1174 dnsa the DNS answer block
1175 rr the RR
1176
e1a3f32f 1177Returns: pointer to a chain of dns_address items; NULL when the dnsa was overrun
059ec3d9
PH
1178*/
1179
1180dns_address *
1181dns_address_from_rr(dns_answer *dnsa, dns_record *rr)
1182{
e1a3f32f
JH
1183dns_address * yield = NULL;
1184uschar * dnsa_lim = dnsa->answer + dnsa->answerlen;
059ec3d9
PH
1185
1186if (rr->type == T_A)
1187 {
d2a2c69b 1188 uschar *p = US rr->data;
e1a3f32f
JH
1189 if (p + 4 <= dnsa_lim)
1190 {
1191 yield = store_get(sizeof(dns_address) + 20);
1192 (void)sprintf(CS yield->address, "%d.%d.%d.%d", p[0], p[1], p[2], p[3]);
1193 yield->next = NULL;
1194 }
059ec3d9
PH
1195 }
1196
1197#if HAVE_IPV6
1198
059ec3d9
PH
1199else
1200 {
e1a3f32f
JH
1201 if (rr->data + 16 <= dnsa_lim)
1202 {
d57d474f
JH
1203 struct in6_addr in6;
1204 int i;
f794c12b 1205 for (i = 0; i < 16; i++) in6.s6_addr[i] = rr->data[i];
e1a3f32f 1206 yield = store_get(sizeof(dns_address) + 50);
d57d474f 1207 inet_ntop(AF_INET6, &in6, CS yield->address, 50);
e1a3f32f
JH
1208 yield->next = NULL;
1209 }
059ec3d9
PH
1210 }
1211#endif /* HAVE_IPV6 */
1212
1213return yield;
1214}
1215
476be7e2
JH
1216
1217
1218void
1219dns_pattern_init(void)
1220{
1221if (check_dns_names_pattern[0] != 0 && !regex_check_dns_names)
1222 regex_check_dns_names =
1223 regex_must_compile(check_dns_names_pattern, FALSE, TRUE);
1224}
1225
8c51eead
JH
1226/* vi: aw ai sw=2
1227*/
059ec3d9 1228/* End of dns.c */