5629d7db2948086149089e5162775c91ad3b45f2
[exim.git] / src / src / host.c
1 /*************************************************
2 * Exim - an Internet mail transport agent *
3 *************************************************/
4
5 /* Copyright (c) University of Cambridge 1995 - 2012 */
6 /* See the file NOTICE for conditions of use and distribution. */
7
8 /* Functions for finding hosts, either by gethostbyname(), gethostbyaddr(), or
9 directly via the DNS. When IPv6 is supported, getipnodebyname() and
10 getipnodebyaddr() may be used instead of gethostbyname() and gethostbyaddr(),
11 if the newer functions are available. This module also contains various other
12 functions concerned with hosts and addresses, and a random number function,
13 used for randomizing hosts with equal MXs but available for use in other parts
14 of Exim. */
15
16
17 #include "exim.h"
18
19
20 /* Static variable for preserving the list of interface addresses in case it is
21 used more than once. */
22
23 static ip_address_item *local_interface_data = NULL;
24
25
26 #ifdef USE_INET_NTOA_FIX
27 /*************************************************
28 * Replacement for broken inet_ntoa() *
29 *************************************************/
30
31 /* On IRIX systems, gcc uses a different structure passing convention to the
32 native libraries. This causes inet_ntoa() to always yield 0.0.0.0 or
33 255.255.255.255. To get round this, we provide a private version of the
34 function here. It is used only if USE_INET_NTOA_FIX is set, which should happen
35 only when gcc is in use on an IRIX system. Code send to me by J.T. Breitner,
36 with these comments:
37
38 code by Stuart Levy
39 as seen in comp.sys.sgi.admin
40
41 August 2005: Apparently this is also needed for AIX systems; USE_INET_NTOA_FIX
42 should now be set for them as well.
43
44 Arguments: sa an in_addr structure
45 Returns: pointer to static text string
46 */
47
48 char *
49 inet_ntoa(struct in_addr sa)
50 {
51 static uschar addr[20];
52 sprintf(addr, "%d.%d.%d.%d",
53 (US &sa.s_addr)[0],
54 (US &sa.s_addr)[1],
55 (US &sa.s_addr)[2],
56 (US &sa.s_addr)[3]);
57 return addr;
58 }
59 #endif
60
61
62
63 /*************************************************
64 * Random number generator *
65 *************************************************/
66
67 /* This is a simple pseudo-random number generator. It does not have to be
68 very good for the uses to which it is put. When running the regression tests,
69 start with a fixed seed.
70
71 If you need better, see vaguely_random_number() which is potentially stronger,
72 if a crypto library is available, but might end up just calling this instead.
73
74 Arguments:
75 limit: one more than the largest number required
76
77 Returns: a pseudo-random number in the range 0 to limit-1
78 */
79
80 int
81 random_number(int limit)
82 {
83 if (limit < 1)
84 return 0;
85 if (random_seed == 0)
86 {
87 if (running_in_test_harness) random_seed = 42; else
88 {
89 int p = (int)getpid();
90 random_seed = (int)time(NULL) ^ ((p << 16) | p);
91 }
92 }
93 random_seed = 1103515245 * random_seed + 12345;
94 return (unsigned int)(random_seed >> 16) % limit;
95 }
96
97 /*************************************************
98 * Wrappers for logging lookup times *
99 *************************************************/
100
101 /* When the 'slow_lookup_log' variable is enabled, these wrappers will
102 write to the log file all (potential) dns lookups that take more than
103 slow_lookup_log milliseconds
104 */
105
106 static void
107 log_long_lookup(const uschar * type, const uschar * data, unsigned long msec)
108 {
109 log_write(0, LOG_MAIN, "Long %s lookup for '%s': %lu msec",
110 type, data, msec);
111 }
112
113
114 /* returns the current system epoch time in milliseconds. */
115 static unsigned long
116 get_time_in_ms()
117 {
118 struct timeval tmp_time;
119 unsigned long seconds, microseconds;
120
121 gettimeofday(&tmp_time, NULL);
122 seconds = (unsigned long) tmp_time.tv_sec;
123 microseconds = (unsigned long) tmp_time.tv_usec;
124 return seconds*1000 + microseconds/1000;
125 }
126
127
128 static int
129 dns_lookup_timerwrap(dns_answer *dnsa, const uschar *name, int type,
130 const uschar **fully_qualified_name)
131 {
132 int retval;
133 unsigned long time_msec;
134
135 if (!slow_lookup_log)
136 return dns_lookup(dnsa, name, type, fully_qualified_name);
137
138 time_msec = get_time_in_ms();
139 retval = dns_lookup(dnsa, name, type, fully_qualified_name);
140 if ((time_msec = get_time_in_ms() - time_msec) > slow_lookup_log)
141 log_long_lookup(US"name", name, time_msec);
142 return retval;
143 }
144
145
146 /*************************************************
147 * Replace gethostbyname() when testing *
148 *************************************************/
149
150 /* This function is called instead of gethostbyname(), gethostbyname2(), or
151 getipnodebyname() when running in the test harness. . It also
152 recognizes an unqualified "localhost" and forces it to the appropriate loopback
153 address. IP addresses are treated as literals. For other names, it uses the DNS
154 to find the host name. In the test harness, this means it will access only the
155 fake DNS resolver.
156
157 Arguments:
158 name the host name or a textual IP address
159 af AF_INET or AF_INET6
160 error_num where to put an error code:
161 HOST_NOT_FOUND/TRY_AGAIN/NO_RECOVERY/NO_DATA
162
163 Returns: a hostent structure or NULL for an error
164 */
165
166 static struct hostent *
167 host_fake_gethostbyname(const uschar *name, int af, int *error_num)
168 {
169 #if HAVE_IPV6
170 int alen = (af == AF_INET)? sizeof(struct in_addr):sizeof(struct in6_addr);
171 #else
172 int alen = sizeof(struct in_addr);
173 #endif
174
175 int ipa;
176 const uschar *lname = name;
177 uschar *adds;
178 uschar **alist;
179 struct hostent *yield;
180 dns_answer dnsa;
181 dns_scan dnss;
182 dns_record *rr;
183
184 DEBUG(D_host_lookup)
185 debug_printf("using host_fake_gethostbyname for %s (%s)\n", name,
186 (af == AF_INET)? "IPv4" : "IPv6");
187
188 /* Handle unqualified "localhost" */
189
190 if (Ustrcmp(name, "localhost") == 0)
191 lname = (af == AF_INET)? US"127.0.0.1" : US"::1";
192
193 /* Handle a literal IP address */
194
195 ipa = string_is_ip_address(lname, NULL);
196 if (ipa != 0)
197 {
198 if ((ipa == 4 && af == AF_INET) ||
199 (ipa == 6 && af == AF_INET6))
200 {
201 int i, n;
202 int x[4];
203 yield = store_get(sizeof(struct hostent));
204 alist = store_get(2 * sizeof(char *));
205 adds = store_get(alen);
206 yield->h_name = CS name;
207 yield->h_aliases = NULL;
208 yield->h_addrtype = af;
209 yield->h_length = alen;
210 yield->h_addr_list = CSS alist;
211 *alist++ = adds;
212 n = host_aton(lname, x);
213 for (i = 0; i < n; i++)
214 {
215 int y = x[i];
216 *adds++ = (y >> 24) & 255;
217 *adds++ = (y >> 16) & 255;
218 *adds++ = (y >> 8) & 255;
219 *adds++ = y & 255;
220 }
221 *alist = NULL;
222 }
223
224 /* Wrong kind of literal address */
225
226 else
227 {
228 *error_num = HOST_NOT_FOUND;
229 return NULL;
230 }
231 }
232
233 /* Handle a host name */
234
235 else
236 {
237 int type = (af == AF_INET)? T_A:T_AAAA;
238 int rc = dns_lookup_timerwrap(&dnsa, lname, type, NULL);
239 int count = 0;
240
241 lookup_dnssec_authenticated = NULL;
242
243 switch(rc)
244 {
245 case DNS_SUCCEED: break;
246 case DNS_NOMATCH: *error_num = HOST_NOT_FOUND; return NULL;
247 case DNS_NODATA: *error_num = NO_DATA; return NULL;
248 case DNS_AGAIN: *error_num = TRY_AGAIN; return NULL;
249 default:
250 case DNS_FAIL: *error_num = NO_RECOVERY; return NULL;
251 }
252
253 for (rr = dns_next_rr(&dnsa, &dnss, RESET_ANSWERS);
254 rr;
255 rr = dns_next_rr(&dnsa, &dnss, RESET_NEXT))
256 if (rr->type == type)
257 count++;
258
259 yield = store_get(sizeof(struct hostent));
260 alist = store_get((count + 1) * sizeof(char **));
261 adds = store_get(count *alen);
262
263 yield->h_name = CS name;
264 yield->h_aliases = NULL;
265 yield->h_addrtype = af;
266 yield->h_length = alen;
267 yield->h_addr_list = CSS alist;
268
269 for (rr = dns_next_rr(&dnsa, &dnss, RESET_ANSWERS);
270 rr;
271 rr = dns_next_rr(&dnsa, &dnss, RESET_NEXT))
272 {
273 int i, n;
274 int x[4];
275 dns_address *da;
276 if (rr->type != type) continue;
277 if (!(da = dns_address_from_rr(&dnsa, rr))) break;
278 *alist++ = adds;
279 n = host_aton(da->address, x);
280 for (i = 0; i < n; i++)
281 {
282 int y = x[i];
283 *adds++ = (y >> 24) & 255;
284 *adds++ = (y >> 16) & 255;
285 *adds++ = (y >> 8) & 255;
286 *adds++ = y & 255;
287 }
288 }
289 *alist = NULL;
290 }
291
292 return yield;
293 }
294
295
296
297 /*************************************************
298 * Build chain of host items from list *
299 *************************************************/
300
301 /* This function builds a chain of host items from a textual list of host
302 names. It does not do any lookups. If randomize is true, the chain is build in
303 a randomized order. There may be multiple groups of independently randomized
304 hosts; they are delimited by a host name consisting of just "+".
305
306 Arguments:
307 anchor anchor for the chain
308 list text list
309 randomize TRUE for randomizing
310
311 Returns: nothing
312 */
313
314 void
315 host_build_hostlist(host_item **anchor, const uschar *list, BOOL randomize)
316 {
317 int sep = 0;
318 int fake_mx = MX_NONE; /* This value is actually -1 */
319 uschar *name;
320
321 if (list == NULL) return;
322 if (randomize) fake_mx--; /* Start at -2 for randomizing */
323
324 *anchor = NULL;
325
326 while ((name = string_nextinlist(&list, &sep, NULL, 0)) != NULL)
327 {
328 host_item *h;
329
330 if (name[0] == '+' && name[1] == 0) /* "+" delimits a randomized group */
331 { /* ignore if not randomizing */
332 if (randomize) fake_mx--;
333 continue;
334 }
335
336 h = store_get(sizeof(host_item));
337 h->name = name;
338 h->address = NULL;
339 h->port = PORT_NONE;
340 h->mx = fake_mx;
341 h->sort_key = randomize? (-fake_mx)*1000 + random_number(1000) : 0;
342 h->status = hstatus_unknown;
343 h->why = hwhy_unknown;
344 h->last_try = 0;
345
346 if (*anchor == NULL)
347 {
348 h->next = NULL;
349 *anchor = h;
350 }
351 else
352 {
353 host_item *hh = *anchor;
354 if (h->sort_key < hh->sort_key)
355 {
356 h->next = hh;
357 *anchor = h;
358 }
359 else
360 {
361 while (hh->next != NULL && h->sort_key >= (hh->next)->sort_key)
362 hh = hh->next;
363 h->next = hh->next;
364 hh->next = h;
365 }
366 }
367 }
368 }
369
370
371
372
373
374 /*************************************************
375 * Extract port from address string *
376 *************************************************/
377
378 /* In the spool file, and in the -oMa and -oMi options, a host plus port is
379 given as an IP address followed by a dot and a port number. This function
380 decodes this.
381
382 An alternative format for the -oMa and -oMi options is [ip address]:port which
383 is what Exim 4 uses for output, because it seems to becoming commonly used,
384 whereas the dot form confuses some programs/people. So we recognize that form
385 too.
386
387 Argument:
388 address points to the string; if there is a port, the '.' in the string
389 is overwritten with zero to terminate the address; if the string
390 is in the [xxx]:ppp format, the address is shifted left and the
391 brackets are removed
392
393 Returns: 0 if there is no port, else the port number. If there's a syntax
394 error, leave the incoming address alone, and return 0.
395 */
396
397 int
398 host_address_extract_port(uschar *address)
399 {
400 int port = 0;
401 uschar *endptr;
402
403 /* Handle the "bracketed with colon on the end" format */
404
405 if (*address == '[')
406 {
407 uschar *rb = address + 1;
408 while (*rb != 0 && *rb != ']') rb++;
409 if (*rb++ == 0) return 0; /* Missing ]; leave invalid address */
410 if (*rb == ':')
411 {
412 port = Ustrtol(rb + 1, &endptr, 10);
413 if (*endptr != 0) return 0; /* Invalid port; leave invalid address */
414 }
415 else if (*rb != 0) return 0; /* Bad syntax; leave invalid address */
416 memmove(address, address + 1, rb - address - 2);
417 rb[-2] = 0;
418 }
419
420 /* Handle the "dot on the end" format */
421
422 else
423 {
424 int skip = -3; /* Skip 3 dots in IPv4 addresses */
425 address--;
426 while (*(++address) != 0)
427 {
428 int ch = *address;
429 if (ch == ':') skip = 0; /* Skip 0 dots in IPv6 addresses */
430 else if (ch == '.' && skip++ >= 0) break;
431 }
432 if (*address == 0) return 0;
433 port = Ustrtol(address + 1, &endptr, 10);
434 if (*endptr != 0) return 0; /* Invalid port; leave invalid address */
435 *address = 0;
436 }
437
438 return port;
439 }
440
441
442 /*************************************************
443 * Get port from a host item's name *
444 *************************************************/
445
446 /* This function is called when finding the IP address for a host that is in a
447 list of hosts explicitly configured, such as in the manualroute router, or in a
448 fallback hosts list. We see if there is a port specification at the end of the
449 host name, and if so, remove it. A minimum length of 3 is required for the
450 original name; nothing shorter is recognized as having a port.
451
452 We test for a name ending with a sequence of digits; if preceded by colon we
453 have a port if the character before the colon is ] and the name starts with [
454 or if there are no other colons in the name (i.e. it's not an IPv6 address).
455
456 Arguments: pointer to the host item
457 Returns: a port number or PORT_NONE
458 */
459
460 int
461 host_item_get_port(host_item *h)
462 {
463 const uschar *p;
464 int port, x;
465 int len = Ustrlen(h->name);
466
467 if (len < 3 || (p = h->name + len - 1, !isdigit(*p))) return PORT_NONE;
468
469 /* Extract potential port number */
470
471 port = *p-- - '0';
472 x = 10;
473
474 while (p > h->name + 1 && isdigit(*p))
475 {
476 port += (*p-- - '0') * x;
477 x *= 10;
478 }
479
480 /* The smallest value of p at this point is h->name + 1. */
481
482 if (*p != ':') return PORT_NONE;
483
484 if (p[-1] == ']' && h->name[0] == '[')
485 h->name = string_copyn(h->name + 1, p - h->name - 2);
486 else if (Ustrchr(h->name, ':') == p)
487 h->name = string_copyn(h->name, p - h->name);
488 else return PORT_NONE;
489
490 DEBUG(D_route|D_host_lookup) debug_printf("host=%s port=%d\n", h->name, port);
491 return port;
492 }
493
494
495
496 #ifndef STAND_ALONE /* Omit when standalone testing */
497
498 /*************************************************
499 * Build sender_fullhost and sender_rcvhost *
500 *************************************************/
501
502 /* This function is called when sender_host_name and/or sender_helo_name
503 have been set. Or might have been set - for a local message read off the spool
504 they won't be. In that case, do nothing. Otherwise, set up the fullhost string
505 as follows:
506
507 (a) No sender_host_name or sender_helo_name: "[ip address]"
508 (b) Just sender_host_name: "host_name [ip address]"
509 (c) Just sender_helo_name: "(helo_name) [ip address]" unless helo is IP
510 in which case: "[ip address}"
511 (d) The two are identical: "host_name [ip address]" includes helo = IP
512 (e) The two are different: "host_name (helo_name) [ip address]"
513
514 If log_incoming_port is set, the sending host's port number is added to the IP
515 address.
516
517 This function also builds sender_rcvhost for use in Received: lines, whose
518 syntax is a bit different. This value also includes the RFC 1413 identity.
519 There wouldn't be two different variables if I had got all this right in the
520 first place.
521
522 Because this data may survive over more than one incoming SMTP message, it has
523 to be in permanent store.
524
525 Arguments: none
526 Returns: nothing
527 */
528
529 void
530 host_build_sender_fullhost(void)
531 {
532 BOOL show_helo = TRUE;
533 uschar *address;
534 int len;
535 int old_pool = store_pool;
536
537 if (sender_host_address == NULL) return;
538
539 store_pool = POOL_PERM;
540
541 /* Set up address, with or without the port. After discussion, it seems that
542 the only format that doesn't cause trouble is [aaaa]:pppp. However, we can't
543 use this directly as the first item for Received: because it ain't an RFC 2822
544 domain. Sigh. */
545
546 address = string_sprintf("[%s]:%d", sender_host_address, sender_host_port);
547 if ((log_extra_selector & LX_incoming_port) == 0 || sender_host_port <= 0)
548 *(Ustrrchr(address, ':')) = 0;
549
550 /* If there's no EHLO/HELO data, we can't show it. */
551
552 if (sender_helo_name == NULL) show_helo = FALSE;
553
554 /* If HELO/EHLO was followed by an IP literal, it's messy because of two
555 features of IPv6. Firstly, there's the "IPv6:" prefix (Exim is liberal and
556 doesn't require this, for historical reasons). Secondly, IPv6 addresses may not
557 be given in canonical form, so we have to canonicize them before comparing. As
558 it happens, the code works for both IPv4 and IPv6. */
559
560 else if (sender_helo_name[0] == '[' &&
561 sender_helo_name[(len=Ustrlen(sender_helo_name))-1] == ']')
562 {
563 int offset = 1;
564 uschar *helo_ip;
565
566 if (strncmpic(sender_helo_name + 1, US"IPv6:", 5) == 0) offset += 5;
567 if (strncmpic(sender_helo_name + 1, US"IPv4:", 5) == 0) offset += 5;
568
569 helo_ip = string_copyn(sender_helo_name + offset, len - offset - 1);
570
571 if (string_is_ip_address(helo_ip, NULL) != 0)
572 {
573 int x[4], y[4];
574 int sizex, sizey;
575 uschar ipx[48], ipy[48]; /* large enough for full IPv6 */
576
577 sizex = host_aton(helo_ip, x);
578 sizey = host_aton(sender_host_address, y);
579
580 (void)host_nmtoa(sizex, x, -1, ipx, ':');
581 (void)host_nmtoa(sizey, y, -1, ipy, ':');
582
583 if (strcmpic(ipx, ipy) == 0) show_helo = FALSE;
584 }
585 }
586
587 /* Host name is not verified */
588
589 if (sender_host_name == NULL)
590 {
591 uschar *portptr = Ustrstr(address, "]:");
592 int size = 0;
593 int ptr = 0;
594 int adlen; /* Sun compiler doesn't like ++ in initializers */
595
596 adlen = (portptr == NULL)? Ustrlen(address) : (++portptr - address);
597 sender_fullhost = (sender_helo_name == NULL)? address :
598 string_sprintf("(%s) %s", sender_helo_name, address);
599
600 sender_rcvhost = string_cat(NULL, &size, &ptr, address, adlen);
601
602 if (sender_ident != NULL || show_helo || portptr != NULL)
603 {
604 int firstptr;
605 sender_rcvhost = string_cat(sender_rcvhost, &size, &ptr, US" (", 2);
606 firstptr = ptr;
607
608 if (portptr != NULL)
609 sender_rcvhost = string_append(sender_rcvhost, &size, &ptr, 2, US"port=",
610 portptr + 1);
611
612 if (show_helo)
613 sender_rcvhost = string_append(sender_rcvhost, &size, &ptr, 2,
614 (firstptr == ptr)? US"helo=" : US" helo=", sender_helo_name);
615
616 if (sender_ident != NULL)
617 sender_rcvhost = string_append(sender_rcvhost, &size, &ptr, 2,
618 (firstptr == ptr)? US"ident=" : US" ident=", sender_ident);
619
620 sender_rcvhost = string_cat(sender_rcvhost, &size, &ptr, US")", 1);
621 }
622
623 sender_rcvhost[ptr] = 0; /* string_cat() always leaves room */
624
625 /* Release store, because string_cat allocated a minimum of 100 bytes that
626 are rarely completely used. */
627
628 store_reset(sender_rcvhost + ptr + 1);
629 }
630
631 /* Host name is known and verified. Unless we've already found that the HELO
632 data matches the IP address, compare it with the name. */
633
634 else
635 {
636 if (show_helo && strcmpic(sender_host_name, sender_helo_name) == 0)
637 show_helo = FALSE;
638
639 if (show_helo)
640 {
641 sender_fullhost = string_sprintf("%s (%s) %s", sender_host_name,
642 sender_helo_name, address);
643 sender_rcvhost = (sender_ident == NULL)?
644 string_sprintf("%s (%s helo=%s)", sender_host_name,
645 address, sender_helo_name) :
646 string_sprintf("%s\n\t(%s helo=%s ident=%s)", sender_host_name,
647 address, sender_helo_name, sender_ident);
648 }
649 else
650 {
651 sender_fullhost = string_sprintf("%s %s", sender_host_name, address);
652 sender_rcvhost = (sender_ident == NULL)?
653 string_sprintf("%s (%s)", sender_host_name, address) :
654 string_sprintf("%s (%s ident=%s)", sender_host_name, address,
655 sender_ident);
656 }
657 }
658
659 store_pool = old_pool;
660
661 DEBUG(D_host_lookup) debug_printf("sender_fullhost = %s\n", sender_fullhost);
662 DEBUG(D_host_lookup) debug_printf("sender_rcvhost = %s\n", sender_rcvhost);
663 }
664
665
666
667 /*************************************************
668 * Build host+ident message *
669 *************************************************/
670
671 /* Used when logging rejections and various ACL and SMTP incidents. The text
672 return depends on whether sender_fullhost and sender_ident are set or not:
673
674 no ident, no host => U=unknown
675 no ident, host set => H=sender_fullhost
676 ident set, no host => U=ident
677 ident set, host set => H=sender_fullhost U=ident
678
679 Arguments:
680 useflag TRUE if first item to be flagged (H= or U=); if there are two
681 items, the second is always flagged
682
683 Returns: pointer to a string in big_buffer
684 */
685
686 uschar *
687 host_and_ident(BOOL useflag)
688 {
689 if (sender_fullhost == NULL)
690 {
691 (void)string_format(big_buffer, big_buffer_size, "%s%s", useflag? "U=" : "",
692 (sender_ident == NULL)? US"unknown" : sender_ident);
693 }
694 else
695 {
696 uschar *flag = useflag? US"H=" : US"";
697 uschar *iface = US"";
698 if ((log_extra_selector & LX_incoming_interface) != 0 &&
699 interface_address != NULL)
700 iface = string_sprintf(" I=[%s]:%d", interface_address, interface_port);
701 if (sender_ident == NULL)
702 (void)string_format(big_buffer, big_buffer_size, "%s%s%s",
703 flag, sender_fullhost, iface);
704 else
705 (void)string_format(big_buffer, big_buffer_size, "%s%s%s U=%s",
706 flag, sender_fullhost, iface, sender_ident);
707 }
708 return big_buffer;
709 }
710
711 #endif /* STAND_ALONE */
712
713
714
715
716 /*************************************************
717 * Build list of local interfaces *
718 *************************************************/
719
720 /* This function interprets the contents of the local_interfaces or
721 extra_local_interfaces options, and creates an ip_address_item block for each
722 item on the list. There is no special interpretation of any IP addresses; in
723 particular, 0.0.0.0 and ::0 are returned without modification. If any address
724 includes a port, it is set in the block. Otherwise the port value is set to
725 zero.
726
727 Arguments:
728 list the list
729 name the name of the option being expanded
730
731 Returns: a chain of ip_address_items, each containing to a textual
732 version of an IP address, and a port number (host order) or
733 zero if no port was given with the address
734 */
735
736 ip_address_item *
737 host_build_ifacelist(const uschar *list, uschar *name)
738 {
739 int sep = 0;
740 uschar *s;
741 uschar buffer[64];
742 ip_address_item *yield = NULL;
743 ip_address_item *last = NULL;
744 ip_address_item *next;
745
746 while ((s = string_nextinlist(&list, &sep, buffer, sizeof(buffer))) != NULL)
747 {
748 int ipv;
749 int port = host_address_extract_port(s); /* Leaves just the IP address */
750 if ((ipv = string_is_ip_address(s, NULL)) == 0)
751 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Malformed IP address \"%s\" in %s",
752 s, name);
753
754 /* Skip IPv6 addresses if IPv6 is disabled. */
755
756 if (disable_ipv6 && ipv == 6) continue;
757
758 /* This use of strcpy() is OK because we have checked that s is a valid IP
759 address above. The field in the ip_address_item is large enough to hold an
760 IPv6 address. */
761
762 next = store_get(sizeof(ip_address_item));
763 next->next = NULL;
764 Ustrcpy(next->address, s);
765 next->port = port;
766 next->v6_include_v4 = FALSE;
767
768 if (yield == NULL) yield = last = next; else
769 {
770 last->next = next;
771 last = next;
772 }
773 }
774
775 return yield;
776 }
777
778
779
780
781
782 /*************************************************
783 * Find addresses on local interfaces *
784 *************************************************/
785
786 /* This function finds the addresses of local IP interfaces. These are used
787 when testing for routing to the local host. As the function may be called more
788 than once, the list is preserved in permanent store, pointed to by a static
789 variable, to save doing the work more than once per process.
790
791 The generic list of interfaces is obtained by calling host_build_ifacelist()
792 for local_interfaces and extra_local_interfaces. This list scanned to remove
793 duplicates (which may exist with different ports - not relevant here). If
794 either of the wildcard IP addresses (0.0.0.0 and ::0) are encountered, they are
795 replaced by the appropriate (IPv4 or IPv6) list of actual local interfaces,
796 obtained from os_find_running_interfaces().
797
798 Arguments: none
799 Returns: a chain of ip_address_items, each containing to a textual
800 version of an IP address; the port numbers are not relevant
801 */
802
803
804 /* First, a local subfunction to add an interface to a list in permanent store,
805 but only if there isn't a previous copy of that address on the list. */
806
807 static ip_address_item *
808 add_unique_interface(ip_address_item *list, ip_address_item *ipa)
809 {
810 ip_address_item *ipa2;
811 for (ipa2 = list; ipa2 != NULL; ipa2 = ipa2->next)
812 if (Ustrcmp(ipa2->address, ipa->address) == 0) return list;
813 ipa2 = store_get_perm(sizeof(ip_address_item));
814 *ipa2 = *ipa;
815 ipa2->next = list;
816 return ipa2;
817 }
818
819
820 /* This is the globally visible function */
821
822 ip_address_item *
823 host_find_interfaces(void)
824 {
825 ip_address_item *running_interfaces = NULL;
826
827 if (local_interface_data == NULL)
828 {
829 void *reset_item = store_get(0);
830 ip_address_item *dlist = host_build_ifacelist(CUS local_interfaces,
831 US"local_interfaces");
832 ip_address_item *xlist = host_build_ifacelist(CUS extra_local_interfaces,
833 US"extra_local_interfaces");
834 ip_address_item *ipa;
835
836 if (dlist == NULL) dlist = xlist; else
837 {
838 for (ipa = dlist; ipa->next != NULL; ipa = ipa->next);
839 ipa->next = xlist;
840 }
841
842 for (ipa = dlist; ipa != NULL; ipa = ipa->next)
843 {
844 if (Ustrcmp(ipa->address, "0.0.0.0") == 0 ||
845 Ustrcmp(ipa->address, "::0") == 0)
846 {
847 ip_address_item *ipa2;
848 BOOL ipv6 = ipa->address[0] == ':';
849 if (running_interfaces == NULL)
850 running_interfaces = os_find_running_interfaces();
851 for (ipa2 = running_interfaces; ipa2 != NULL; ipa2 = ipa2->next)
852 {
853 if ((Ustrchr(ipa2->address, ':') != NULL) == ipv6)
854 local_interface_data = add_unique_interface(local_interface_data,
855 ipa2);
856 }
857 }
858 else
859 {
860 local_interface_data = add_unique_interface(local_interface_data, ipa);
861 DEBUG(D_interface)
862 {
863 debug_printf("Configured local interface: address=%s", ipa->address);
864 if (ipa->port != 0) debug_printf(" port=%d", ipa->port);
865 debug_printf("\n");
866 }
867 }
868 }
869 store_reset(reset_item);
870 }
871
872 return local_interface_data;
873 }
874
875
876
877
878
879 /*************************************************
880 * Convert network IP address to text *
881 *************************************************/
882
883 /* Given an IPv4 or IPv6 address in binary, convert it to a text
884 string and return the result in a piece of new store. The address can
885 either be given directly, or passed over in a sockaddr structure. Note
886 that this isn't the converse of host_aton() because of byte ordering
887 differences. See host_nmtoa() below.
888
889 Arguments:
890 type if < 0 then arg points to a sockaddr, else
891 either AF_INET or AF_INET6
892 arg points to a sockaddr if type is < 0, or
893 points to an IPv4 address (32 bits), or
894 points to an IPv6 address (128 bits),
895 in both cases, in network byte order
896 buffer if NULL, the result is returned in gotten store;
897 else points to a buffer to hold the answer
898 portptr points to where to put the port number, if non NULL; only
899 used when type < 0
900
901 Returns: pointer to character string
902 */
903
904 uschar *
905 host_ntoa(int type, const void *arg, uschar *buffer, int *portptr)
906 {
907 uschar *yield;
908
909 /* The new world. It is annoying that we have to fish out the address from
910 different places in the block, depending on what kind of address it is. It
911 is also a pain that inet_ntop() returns a const uschar *, whereas the IPv4
912 function inet_ntoa() returns just uschar *, and some picky compilers insist
913 on warning if one assigns a const uschar * to a uschar *. Hence the casts. */
914
915 #if HAVE_IPV6
916 uschar addr_buffer[46];
917 if (type < 0)
918 {
919 int family = ((struct sockaddr *)arg)->sa_family;
920 if (family == AF_INET6)
921 {
922 struct sockaddr_in6 *sk = (struct sockaddr_in6 *)arg;
923 yield = (uschar *)inet_ntop(family, &(sk->sin6_addr), CS addr_buffer,
924 sizeof(addr_buffer));
925 if (portptr != NULL) *portptr = ntohs(sk->sin6_port);
926 }
927 else
928 {
929 struct sockaddr_in *sk = (struct sockaddr_in *)arg;
930 yield = (uschar *)inet_ntop(family, &(sk->sin_addr), CS addr_buffer,
931 sizeof(addr_buffer));
932 if (portptr != NULL) *portptr = ntohs(sk->sin_port);
933 }
934 }
935 else
936 {
937 yield = (uschar *)inet_ntop(type, arg, CS addr_buffer, sizeof(addr_buffer));
938 }
939
940 /* If the result is a mapped IPv4 address, show it in V4 format. */
941
942 if (Ustrncmp(yield, "::ffff:", 7) == 0) yield += 7;
943
944 #else /* HAVE_IPV6 */
945
946 /* The old world */
947
948 if (type < 0)
949 {
950 yield = US inet_ntoa(((struct sockaddr_in *)arg)->sin_addr);
951 if (portptr != NULL) *portptr = ntohs(((struct sockaddr_in *)arg)->sin_port);
952 }
953 else
954 yield = US inet_ntoa(*((struct in_addr *)arg));
955 #endif
956
957 /* If there is no buffer, put the string into some new store. */
958
959 if (buffer == NULL) return string_copy(yield);
960
961 /* Callers of this function with a non-NULL buffer must ensure that it is
962 large enough to hold an IPv6 address, namely, at least 46 bytes. That's what
963 makes this use of strcpy() OK. */
964
965 Ustrcpy(buffer, yield);
966 return buffer;
967 }
968
969
970
971
972 /*************************************************
973 * Convert address text to binary *
974 *************************************************/
975
976 /* Given the textual form of an IP address, convert it to binary in an
977 array of ints. IPv4 addresses occupy one int; IPv6 addresses occupy 4 ints.
978 The result has the first byte in the most significant byte of the first int. In
979 other words, the result is not in network byte order, but in host byte order.
980 As a result, this is not the converse of host_ntoa(), which expects network
981 byte order. See host_nmtoa() below.
982
983 Arguments:
984 address points to the textual address, checked for syntax
985 bin points to an array of 4 ints
986
987 Returns: the number of ints used
988 */
989
990 int
991 host_aton(const uschar *address, int *bin)
992 {
993 int x[4];
994 int v4offset = 0;
995
996 /* Handle IPv6 address, which may end with an IPv4 address. It may also end
997 with a "scope", introduced by a percent sign. This code is NOT enclosed in #if
998 HAVE_IPV6 in order that IPv6 addresses are recognized even if IPv6 is not
999 supported. */
1000
1001 if (Ustrchr(address, ':') != NULL)
1002 {
1003 const uschar *p = address;
1004 const uschar *component[8];
1005 BOOL ipv4_ends = FALSE;
1006 int ci = 0;
1007 int nulloffset = 0;
1008 int v6count = 8;
1009 int i;
1010
1011 /* If the address starts with a colon, it will start with two colons.
1012 Just lose the first one, which will leave a null first component. */
1013
1014 if (*p == ':') p++;
1015
1016 /* Split the address into components separated by colons. The input address
1017 is supposed to be checked for syntax. There was a case where this was
1018 overlooked; to guard against that happening again, check here and crash if
1019 there are too many components. */
1020
1021 while (*p != 0 && *p != '%')
1022 {
1023 int len = Ustrcspn(p, ":%");
1024 if (len == 0) nulloffset = ci;
1025 if (ci > 7) log_write(0, LOG_MAIN|LOG_PANIC_DIE,
1026 "Internal error: invalid IPv6 address \"%s\" passed to host_aton()",
1027 address);
1028 component[ci++] = p;
1029 p += len;
1030 if (*p == ':') p++;
1031 }
1032
1033 /* If the final component contains a dot, it is a trailing v4 address.
1034 As the syntax is known to be checked, just set up for a trailing
1035 v4 address and restrict the v6 part to 6 components. */
1036
1037 if (Ustrchr(component[ci-1], '.') != NULL)
1038 {
1039 address = component[--ci];
1040 ipv4_ends = TRUE;
1041 v4offset = 3;
1042 v6count = 6;
1043 }
1044
1045 /* If there are fewer than 6 or 8 components, we have to insert some
1046 more empty ones in the middle. */
1047
1048 if (ci < v6count)
1049 {
1050 int insert_count = v6count - ci;
1051 for (i = v6count-1; i > nulloffset + insert_count; i--)
1052 component[i] = component[i - insert_count];
1053 while (i > nulloffset) component[i--] = US"";
1054 }
1055
1056 /* Now turn the components into binary in pairs and bung them
1057 into the vector of ints. */
1058
1059 for (i = 0; i < v6count; i += 2)
1060 bin[i/2] = (Ustrtol(component[i], NULL, 16) << 16) +
1061 Ustrtol(component[i+1], NULL, 16);
1062
1063 /* If there was no terminating v4 component, we are done. */
1064
1065 if (!ipv4_ends) return 4;
1066 }
1067
1068 /* Handle IPv4 address */
1069
1070 (void)sscanf(CS address, "%d.%d.%d.%d", x, x+1, x+2, x+3);
1071 bin[v4offset] = (x[0] << 24) + (x[1] << 16) + (x[2] << 8) + x[3];
1072 return v4offset+1;
1073 }
1074
1075
1076 /*************************************************
1077 * Apply mask to an IP address *
1078 *************************************************/
1079
1080 /* Mask an address held in 1 or 4 ints, with the ms bit in the ms bit of the
1081 first int, etc.
1082
1083 Arguments:
1084 count the number of ints
1085 binary points to the ints to be masked
1086 mask the count of ms bits to leave, or -1 if no masking
1087
1088 Returns: nothing
1089 */
1090
1091 void
1092 host_mask(int count, int *binary, int mask)
1093 {
1094 int i;
1095 if (mask < 0) mask = 99999;
1096 for (i = 0; i < count; i++)
1097 {
1098 int wordmask;
1099 if (mask == 0) wordmask = 0;
1100 else if (mask < 32)
1101 {
1102 wordmask = (-1) << (32 - mask);
1103 mask = 0;
1104 }
1105 else
1106 {
1107 wordmask = -1;
1108 mask -= 32;
1109 }
1110 binary[i] &= wordmask;
1111 }
1112 }
1113
1114
1115
1116
1117 /*************************************************
1118 * Convert masked IP address in ints to text *
1119 *************************************************/
1120
1121 /* We can't use host_ntoa() because it assumes the binary values are in network
1122 byte order, and these are the result of host_aton(), which puts them in ints in
1123 host byte order. Also, we really want IPv6 addresses to be in a canonical
1124 format, so we output them with no abbreviation. In a number of cases we can't
1125 use the normal colon separator in them because it terminates keys in lsearch
1126 files, so we want to use dot instead. There's an argument that specifies what
1127 to use for IPv6 addresses.
1128
1129 Arguments:
1130 count 1 or 4 (number of ints)
1131 binary points to the ints
1132 mask mask value; if < 0 don't add to result
1133 buffer big enough to hold the result
1134 sep component separator character for IPv6 addresses
1135
1136 Returns: the number of characters placed in buffer, not counting
1137 the final nul.
1138 */
1139
1140 int
1141 host_nmtoa(int count, int *binary, int mask, uschar *buffer, int sep)
1142 {
1143 int i, j;
1144 uschar *tt = buffer;
1145
1146 if (count == 1)
1147 {
1148 j = binary[0];
1149 for (i = 24; i >= 0; i -= 8)
1150 {
1151 sprintf(CS tt, "%d.", (j >> i) & 255);
1152 while (*tt) tt++;
1153 }
1154 }
1155 else
1156 {
1157 for (i = 0; i < 4; i++)
1158 {
1159 j = binary[i];
1160 sprintf(CS tt, "%04x%c%04x%c", (j >> 16) & 0xffff, sep, j & 0xffff, sep);
1161 while (*tt) tt++;
1162 }
1163 }
1164
1165 tt--; /* lose final separator */
1166
1167 if (mask < 0)
1168 *tt = 0;
1169 else
1170 {
1171 sprintf(CS tt, "/%d", mask);
1172 while (*tt) tt++;
1173 }
1174
1175 return tt - buffer;
1176 }
1177
1178
1179
1180 /*************************************************
1181 * Check port for tls_on_connect *
1182 *************************************************/
1183
1184 /* This function checks whether a given incoming port is configured for tls-
1185 on-connect. It is called from the daemon and from inetd handling. If the global
1186 option tls_on_connect is already set, all ports operate this way. Otherwise, we
1187 check the tls_on_connect_ports option for a list of ports.
1188
1189 Argument: a port number
1190 Returns: TRUE or FALSE
1191 */
1192
1193 BOOL
1194 host_is_tls_on_connect_port(int port)
1195 {
1196 int sep = 0;
1197 uschar buffer[32];
1198 const uschar *list = tls_in.on_connect_ports;
1199 uschar *s;
1200 uschar *end;
1201
1202 if (tls_in.on_connect) return TRUE;
1203
1204 while ((s = string_nextinlist(&list, &sep, buffer, sizeof(buffer))))
1205 if (Ustrtol(s, &end, 10) == port)
1206 return TRUE;
1207
1208 return FALSE;
1209 }
1210
1211
1212
1213 /*************************************************
1214 * Check whether host is in a network *
1215 *************************************************/
1216
1217 /* This function checks whether a given IP address matches a pattern that
1218 represents either a single host, or a network (using CIDR notation). The caller
1219 of this function must check the syntax of the arguments before calling it.
1220
1221 Arguments:
1222 host string representation of the ip-address to check
1223 net string representation of the network, with optional CIDR mask
1224 maskoffset offset to the / that introduces the mask in the key
1225 zero if there is no mask
1226
1227 Returns:
1228 TRUE the host is inside the network
1229 FALSE the host is NOT inside the network
1230 */
1231
1232 BOOL
1233 host_is_in_net(const uschar *host, const uschar *net, int maskoffset)
1234 {
1235 int i;
1236 int address[4];
1237 int incoming[4];
1238 int mlen;
1239 int size = host_aton(net, address);
1240 int insize;
1241
1242 /* No mask => all bits to be checked */
1243
1244 if (maskoffset == 0) mlen = 99999; /* Big number */
1245 else mlen = Uatoi(net + maskoffset + 1);
1246
1247 /* Convert the incoming address to binary. */
1248
1249 insize = host_aton(host, incoming);
1250
1251 /* Convert IPv4 addresses given in IPv6 compatible mode, which represent
1252 connections from IPv4 hosts to IPv6 hosts, that is, addresses of the form
1253 ::ffff:<v4address>, to IPv4 format. */
1254
1255 if (insize == 4 && incoming[0] == 0 && incoming[1] == 0 &&
1256 incoming[2] == 0xffff)
1257 {
1258 insize = 1;
1259 incoming[0] = incoming[3];
1260 }
1261
1262 /* No match if the sizes don't agree. */
1263
1264 if (insize != size) return FALSE;
1265
1266 /* Else do the masked comparison. */
1267
1268 for (i = 0; i < size; i++)
1269 {
1270 int mask;
1271 if (mlen == 0) mask = 0;
1272 else if (mlen < 32)
1273 {
1274 mask = (-1) << (32 - mlen);
1275 mlen = 0;
1276 }
1277 else
1278 {
1279 mask = -1;
1280 mlen -= 32;
1281 }
1282 if ((incoming[i] & mask) != (address[i] & mask)) return FALSE;
1283 }
1284
1285 return TRUE;
1286 }
1287
1288
1289
1290 /*************************************************
1291 * Scan host list for local hosts *
1292 *************************************************/
1293
1294 /* Scan through a chain of addresses and check whether any of them is the
1295 address of an interface on the local machine. If so, remove that address and
1296 any previous ones with the same MX value, and all subsequent ones (which will
1297 have greater or equal MX values) from the chain. Note: marking them as unusable
1298 is NOT the right thing to do because it causes the hosts not to be used for
1299 other domains, for which they may well be correct.
1300
1301 The hosts may be part of a longer chain; we only process those between the
1302 initial pointer and the "last" pointer.
1303
1304 There is also a list of "pseudo-local" host names which are checked against the
1305 host names. Any match causes that host item to be treated the same as one which
1306 matches a local IP address.
1307
1308 If the very first host is a local host, then all MX records had a precedence
1309 greater than or equal to that of the local host. Either there's a problem in
1310 the DNS, or an apparently remote name turned out to be an abbreviation for the
1311 local host. Give a specific return code, and let the caller decide what to do.
1312 Otherwise, give a success code if at least one host address has been found.
1313
1314 Arguments:
1315 host pointer to the first host in the chain
1316 lastptr pointer to pointer to the last host in the chain (may be updated)
1317 removed if not NULL, set TRUE if some local addresses were removed
1318 from the list
1319
1320 Returns:
1321 HOST_FOUND if there is at least one host with an IP address on the chain
1322 and an MX value less than any MX value associated with the
1323 local host
1324 HOST_FOUND_LOCAL if a local host is among the lowest-numbered MX hosts; when
1325 the host addresses were obtained from A records or
1326 gethostbyname(), the MX values are set to -1.
1327 HOST_FIND_FAILED if no valid hosts with set IP addresses were found
1328 */
1329
1330 int
1331 host_scan_for_local_hosts(host_item *host, host_item **lastptr, BOOL *removed)
1332 {
1333 int yield = HOST_FIND_FAILED;
1334 host_item *last = *lastptr;
1335 host_item *prev = NULL;
1336 host_item *h;
1337
1338 if (removed != NULL) *removed = FALSE;
1339
1340 if (local_interface_data == NULL) local_interface_data = host_find_interfaces();
1341
1342 for (h = host; h != last->next; h = h->next)
1343 {
1344 #ifndef STAND_ALONE
1345 if (hosts_treat_as_local != NULL)
1346 {
1347 int rc;
1348 const uschar *save = deliver_domain;
1349 deliver_domain = h->name; /* set $domain */
1350 rc = match_isinlist(string_copylc(h->name), CUSS &hosts_treat_as_local, 0,
1351 &domainlist_anchor, NULL, MCL_DOMAIN, TRUE, NULL);
1352 deliver_domain = save;
1353 if (rc == OK) goto FOUND_LOCAL;
1354 }
1355 #endif
1356
1357 /* It seems that on many operating systems, 0.0.0.0 is treated as a synonym
1358 for 127.0.0.1 and refers to the local host. We therefore force it always to
1359 be treated as local. */
1360
1361 if (h->address != NULL)
1362 {
1363 ip_address_item *ip;
1364 if (Ustrcmp(h->address, "0.0.0.0") == 0) goto FOUND_LOCAL;
1365 for (ip = local_interface_data; ip != NULL; ip = ip->next)
1366 if (Ustrcmp(h->address, ip->address) == 0) goto FOUND_LOCAL;
1367 yield = HOST_FOUND; /* At least one remote address has been found */
1368 }
1369
1370 /* Update prev to point to the last host item before any that have
1371 the same MX value as the one we have just considered. */
1372
1373 if (h->next == NULL || h->next->mx != h->mx) prev = h;
1374 }
1375
1376 return yield; /* No local hosts found: return HOST_FOUND or HOST_FIND_FAILED */
1377
1378 /* A host whose IP address matches a local IP address, or whose name matches
1379 something in hosts_treat_as_local has been found. */
1380
1381 FOUND_LOCAL:
1382
1383 if (prev == NULL)
1384 {
1385 HDEBUG(D_host_lookup) debug_printf((h->mx >= 0)?
1386 "local host has lowest MX\n" :
1387 "local host found for non-MX address\n");
1388 return HOST_FOUND_LOCAL;
1389 }
1390
1391 HDEBUG(D_host_lookup)
1392 {
1393 debug_printf("local host in host list - removed hosts:\n");
1394 for (h = prev->next; h != last->next; h = h->next)
1395 debug_printf(" %s %s %d\n", h->name, h->address, h->mx);
1396 }
1397
1398 if (removed != NULL) *removed = TRUE;
1399 prev->next = last->next;
1400 *lastptr = prev;
1401 return yield;
1402 }
1403
1404
1405
1406
1407 /*************************************************
1408 * Remove duplicate IPs in host list *
1409 *************************************************/
1410
1411 /* You would think that administrators could set up their DNS records so that
1412 one ended up with a list of unique IP addresses after looking up A or MX
1413 records, but apparently duplication is common. So we scan such lists and
1414 remove the later duplicates. Note that we may get lists in which some host
1415 addresses are not set.
1416
1417 Arguments:
1418 host pointer to the first host in the chain
1419 lastptr pointer to pointer to the last host in the chain (may be updated)
1420
1421 Returns: nothing
1422 */
1423
1424 static void
1425 host_remove_duplicates(host_item *host, host_item **lastptr)
1426 {
1427 while (host != *lastptr)
1428 {
1429 if (host->address != NULL)
1430 {
1431 host_item *h = host;
1432 while (h != *lastptr)
1433 {
1434 if (h->next->address != NULL &&
1435 Ustrcmp(h->next->address, host->address) == 0)
1436 {
1437 DEBUG(D_host_lookup) debug_printf("duplicate IP address %s (MX=%d) "
1438 "removed\n", host->address, h->next->mx);
1439 if (h->next == *lastptr) *lastptr = h;
1440 h->next = h->next->next;
1441 }
1442 else h = h->next;
1443 }
1444 }
1445 /* If the last item was removed, host may have become == *lastptr */
1446 if (host != *lastptr) host = host->next;
1447 }
1448 }
1449
1450
1451
1452
1453 /*************************************************
1454 * Find sender host name by gethostbyaddr() *
1455 *************************************************/
1456
1457 /* This used to be the only way it was done, but it turns out that not all
1458 systems give aliases for calls to gethostbyaddr() - or one of the modern
1459 equivalents like getipnodebyaddr(). Fortunately, multiple PTR records are rare,
1460 but they can still exist. This function is now used only when a DNS lookup of
1461 the IP address fails, in order to give access to /etc/hosts.
1462
1463 Arguments: none
1464 Returns: OK, DEFER, FAIL
1465 */
1466
1467 static int
1468 host_name_lookup_byaddr(void)
1469 {
1470 int len;
1471 uschar *s, *t;
1472 struct hostent *hosts;
1473 struct in_addr addr;
1474 unsigned long time_msec;
1475
1476 if (slow_lookup_log) time_msec = get_time_in_ms();
1477
1478 /* Lookup on IPv6 system */
1479
1480 #if HAVE_IPV6
1481 if (Ustrchr(sender_host_address, ':') != NULL)
1482 {
1483 struct in6_addr addr6;
1484 if (inet_pton(AF_INET6, CS sender_host_address, &addr6) != 1)
1485 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "unable to parse \"%s\" as an "
1486 "IPv6 address", sender_host_address);
1487 #if HAVE_GETIPNODEBYADDR
1488 hosts = getipnodebyaddr(CS &addr6, sizeof(addr6), AF_INET6, &h_errno);
1489 #else
1490 hosts = gethostbyaddr(CS &addr6, sizeof(addr6), AF_INET6);
1491 #endif
1492 }
1493 else
1494 {
1495 if (inet_pton(AF_INET, CS sender_host_address, &addr) != 1)
1496 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "unable to parse \"%s\" as an "
1497 "IPv4 address", sender_host_address);
1498 #if HAVE_GETIPNODEBYADDR
1499 hosts = getipnodebyaddr(CS &addr, sizeof(addr), AF_INET, &h_errno);
1500 #else
1501 hosts = gethostbyaddr(CS &addr, sizeof(addr), AF_INET);
1502 #endif
1503 }
1504
1505 /* Do lookup on IPv4 system */
1506
1507 #else
1508 addr.s_addr = (S_ADDR_TYPE)inet_addr(CS sender_host_address);
1509 hosts = gethostbyaddr(CS(&addr), sizeof(addr), AF_INET);
1510 #endif
1511
1512 if ( slow_lookup_log
1513 && (time_msec = get_time_in_ms() - time_msec) > slow_lookup_log
1514 )
1515 log_long_lookup(US"name", sender_host_address, time_msec);
1516
1517 /* Failed to look up the host. */
1518
1519 if (hosts == NULL)
1520 {
1521 HDEBUG(D_host_lookup) debug_printf("IP address lookup failed: h_errno=%d\n",
1522 h_errno);
1523 return (h_errno == TRY_AGAIN || h_errno == NO_RECOVERY) ? DEFER : FAIL;
1524 }
1525
1526 /* It seems there are some records in the DNS that yield an empty name. We
1527 treat this as non-existent. In some operating systems, this is returned as an
1528 empty string; in others as a single dot. */
1529
1530 if (hosts->h_name == NULL || hosts->h_name[0] == 0 || hosts->h_name[0] == '.')
1531 {
1532 HDEBUG(D_host_lookup) debug_printf("IP address lookup yielded an empty name: "
1533 "treated as non-existent host name\n");
1534 return FAIL;
1535 }
1536
1537 /* Copy and lowercase the name, which is in static storage in many systems.
1538 Put it in permanent memory. */
1539
1540 s = (uschar *)hosts->h_name;
1541 len = Ustrlen(s) + 1;
1542 t = sender_host_name = store_get_perm(len);
1543 while (*s != 0) *t++ = tolower(*s++);
1544 *t = 0;
1545
1546 /* If the host has aliases, build a copy of the alias list */
1547
1548 if (hosts->h_aliases != NULL)
1549 {
1550 int count = 1;
1551 uschar **aliases, **ptr;
1552 for (aliases = USS hosts->h_aliases; *aliases != NULL; aliases++) count++;
1553 ptr = sender_host_aliases = store_get_perm(count * sizeof(uschar *));
1554 for (aliases = USS hosts->h_aliases; *aliases != NULL; aliases++)
1555 {
1556 uschar *s = *aliases;
1557 int len = Ustrlen(s) + 1;
1558 uschar *t = *ptr++ = store_get_perm(len);
1559 while (*s != 0) *t++ = tolower(*s++);
1560 *t = 0;
1561 }
1562 *ptr = NULL;
1563 }
1564
1565 return OK;
1566 }
1567
1568
1569
1570 /*************************************************
1571 * Find host name for incoming call *
1572 *************************************************/
1573
1574 /* Put the name in permanent store, pointed to by sender_host_name. We also set
1575 up a list of alias names, pointed to by sender_host_alias. The list is
1576 NULL-terminated. The incoming address is in sender_host_address, either in
1577 dotted-quad form for IPv4 or in colon-separated form for IPv6.
1578
1579 This function does a thorough check that the names it finds point back to the
1580 incoming IP address. Any that do not are discarded. Note that this is relied on
1581 by the ACL reverse_host_lookup check.
1582
1583 On some systems, get{host,ipnode}byaddr() appears to do this internally, but
1584 this it not universally true. Also, for release 4.30, this function was changed
1585 to do a direct DNS lookup first, by default[1], because it turns out that that
1586 is the only guaranteed way to find all the aliases on some systems. My
1587 experiments indicate that Solaris gethostbyaddr() gives the aliases for but
1588 Linux does not.
1589
1590 [1] The actual order is controlled by the host_lookup_order option.
1591
1592 Arguments: none
1593 Returns: OK on success, the answer being placed in the global variable
1594 sender_host_name, with any aliases in a list hung off
1595 sender_host_aliases
1596 FAIL if no host name can be found
1597 DEFER if a temporary error was encountered
1598
1599 The variable host_lookup_msg is set to an empty string on sucess, or to a
1600 reason for the failure otherwise, in a form suitable for tagging onto an error
1601 message, and also host_lookup_failed is set TRUE if the lookup failed. If there
1602 was a defer, host_lookup_deferred is set TRUE.
1603
1604 Any dynamically constructed string for host_lookup_msg must be in permanent
1605 store, because it might be used for several incoming messages on the same SMTP
1606 connection. */
1607
1608 int
1609 host_name_lookup(void)
1610 {
1611 int old_pool, rc;
1612 int sep = 0;
1613 uschar *hname, *save_hostname;
1614 uschar **aliases;
1615 uschar buffer[256];
1616 uschar *ordername;
1617 const uschar *list = host_lookup_order;
1618 dns_record *rr;
1619 dns_answer dnsa;
1620 dns_scan dnss;
1621
1622 sender_host_dnssec = host_lookup_deferred = host_lookup_failed = FALSE;
1623
1624 HDEBUG(D_host_lookup)
1625 debug_printf("looking up host name for %s\n", sender_host_address);
1626
1627 /* For testing the case when a lookup does not complete, we have a special
1628 reserved IP address. */
1629
1630 if (running_in_test_harness &&
1631 Ustrcmp(sender_host_address, "99.99.99.99") == 0)
1632 {
1633 HDEBUG(D_host_lookup)
1634 debug_printf("Test harness: host name lookup returns DEFER\n");
1635 host_lookup_deferred = TRUE;
1636 return DEFER;
1637 }
1638
1639 /* Do lookups directly in the DNS or via gethostbyaddr() (or equivalent), in
1640 the order specified by the host_lookup_order option. */
1641
1642 while ((ordername = string_nextinlist(&list, &sep, buffer, sizeof(buffer))))
1643 {
1644 if (strcmpic(ordername, US"bydns") == 0)
1645 {
1646 dns_init(FALSE, FALSE, FALSE); /* dnssec ctrl by dns_dnssec_ok glbl */
1647 dns_build_reverse(sender_host_address, buffer);
1648 rc = dns_lookup_timerwrap(&dnsa, buffer, T_PTR, NULL);
1649
1650 /* The first record we come across is used for the name; others are
1651 considered to be aliases. We have to scan twice, in order to find out the
1652 number of aliases. However, if all the names are empty, we will behave as
1653 if failure. (PTR records that yield empty names have been encountered in
1654 the DNS.) */
1655
1656 if (rc == DNS_SUCCEED)
1657 {
1658 uschar **aptr = NULL;
1659 int ssize = 264;
1660 int count = 0;
1661 int old_pool = store_pool;
1662
1663 sender_host_dnssec = dns_is_secure(&dnsa);
1664 DEBUG(D_dns)
1665 debug_printf("Reverse DNS security status: %s\n",
1666 sender_host_dnssec ? "DNSSEC verified (AD)" : "unverified");
1667
1668 store_pool = POOL_PERM; /* Save names in permanent storage */
1669
1670 for (rr = dns_next_rr(&dnsa, &dnss, RESET_ANSWERS);
1671 rr;
1672 rr = dns_next_rr(&dnsa, &dnss, RESET_NEXT))
1673 if (rr->type == T_PTR)
1674 count++;
1675
1676 /* Get store for the list of aliases. For compatibility with
1677 gethostbyaddr, we make an empty list if there are none. */
1678
1679 aptr = sender_host_aliases = store_get(count * sizeof(uschar *));
1680
1681 /* Re-scan and extract the names */
1682
1683 for (rr = dns_next_rr(&dnsa, &dnss, RESET_ANSWERS);
1684 rr;
1685 rr = dns_next_rr(&dnsa, &dnss, RESET_NEXT))
1686 {
1687 uschar *s = NULL;
1688 if (rr->type != T_PTR) continue;
1689 s = store_get(ssize);
1690
1691 /* If an overlong response was received, the data will have been
1692 truncated and dn_expand may fail. */
1693
1694 if (dn_expand(dnsa.answer, dnsa.answer + dnsa.answerlen,
1695 (uschar *)(rr->data), (DN_EXPAND_ARG4_TYPE)(s), ssize) < 0)
1696 {
1697 log_write(0, LOG_MAIN, "host name alias list truncated for %s",
1698 sender_host_address);
1699 break;
1700 }
1701
1702 store_reset(s + Ustrlen(s) + 1);
1703 if (s[0] == 0)
1704 {
1705 HDEBUG(D_host_lookup) debug_printf("IP address lookup yielded an "
1706 "empty name: treated as non-existent host name\n");
1707 continue;
1708 }
1709 if (!sender_host_name) sender_host_name = s;
1710 else *aptr++ = s;
1711 while (*s != 0) { *s = tolower(*s); s++; }
1712 }
1713
1714 *aptr = NULL; /* End of alias list */
1715 store_pool = old_pool; /* Reset store pool */
1716
1717 /* If we've found a names, break out of the "order" loop */
1718
1719 if (sender_host_name != NULL) break;
1720 }
1721
1722 /* If the DNS lookup deferred, we must also defer. */
1723
1724 if (rc == DNS_AGAIN)
1725 {
1726 HDEBUG(D_host_lookup)
1727 debug_printf("IP address PTR lookup gave temporary error\n");
1728 host_lookup_deferred = TRUE;
1729 return DEFER;
1730 }
1731 }
1732
1733 /* Do a lookup using gethostbyaddr() - or equivalent */
1734
1735 else if (strcmpic(ordername, US"byaddr") == 0)
1736 {
1737 HDEBUG(D_host_lookup)
1738 debug_printf("IP address lookup using gethostbyaddr()\n");
1739 rc = host_name_lookup_byaddr();
1740 if (rc == DEFER)
1741 {
1742 host_lookup_deferred = TRUE;
1743 return rc; /* Can't carry on */
1744 }
1745 if (rc == OK) break; /* Found a name */
1746 }
1747 } /* Loop for bydns/byaddr scanning */
1748
1749 /* If we have failed to find a name, return FAIL and log when required.
1750 NB host_lookup_msg must be in permanent store. */
1751
1752 if (sender_host_name == NULL)
1753 {
1754 if (host_checking || !log_testing_mode)
1755 log_write(L_host_lookup_failed, LOG_MAIN, "no host name found for IP "
1756 "address %s", sender_host_address);
1757 host_lookup_msg = US" (failed to find host name from IP address)";
1758 host_lookup_failed = TRUE;
1759 return FAIL;
1760 }
1761
1762 HDEBUG(D_host_lookup)
1763 {
1764 uschar **aliases = sender_host_aliases;
1765 debug_printf("IP address lookup yielded \"%s\"\n", sender_host_name);
1766 while (*aliases != NULL) debug_printf(" alias \"%s\"\n", *aliases++);
1767 }
1768
1769 /* We need to verify that a forward lookup on the name we found does indeed
1770 correspond to the address. This is for security: in principle a malefactor who
1771 happened to own a reverse zone could set it to point to any names at all.
1772
1773 This code was present in versions of Exim before 3.20. At that point I took it
1774 out because I thought that gethostbyaddr() did the check anyway. It turns out
1775 that this isn't always the case, so it's coming back in at 4.01. This version
1776 is actually better, because it also checks aliases.
1777
1778 The code was made more robust at release 4.21. Prior to that, it accepted all
1779 the names if any of them had the correct IP address. Now the code checks all
1780 the names, and accepts only those that have the correct IP address. */
1781
1782 save_hostname = sender_host_name; /* Save for error messages */
1783 aliases = sender_host_aliases;
1784 for (hname = sender_host_name; hname != NULL; hname = *aliases++)
1785 {
1786 int rc;
1787 BOOL ok = FALSE;
1788 host_item h;
1789 dnssec_domains d;
1790
1791 h.next = NULL;
1792 h.name = hname;
1793 h.mx = MX_NONE;
1794 h.address = NULL;
1795 d.request = sender_host_dnssec ? US"*" : NULL;;
1796 d.require = NULL;
1797
1798 if ( (rc = host_find_bydns(&h, NULL, HOST_FIND_BY_A,
1799 NULL, NULL, NULL, &d, NULL, NULL)) == HOST_FOUND
1800 || rc == HOST_FOUND_LOCAL
1801 )
1802 {
1803 host_item *hh;
1804 HDEBUG(D_host_lookup) debug_printf("checking addresses for %s\n", hname);
1805
1806 /* If the forward lookup was not secure we cancel the is-secure variable */
1807
1808 DEBUG(D_dns) debug_printf("Forward DNS security status: %s\n",
1809 h.dnssec == DS_YES ? "DNSSEC verified (AD)" : "unverified");
1810 if (h.dnssec != DS_YES) sender_host_dnssec = FALSE;
1811
1812 for (hh = &h; hh != NULL; hh = hh->next)
1813 if (host_is_in_net(hh->address, sender_host_address, 0))
1814 {
1815 HDEBUG(D_host_lookup) debug_printf(" %s OK\n", hh->address);
1816 ok = TRUE;
1817 break;
1818 }
1819 else
1820 HDEBUG(D_host_lookup) debug_printf(" %s\n", hh->address);
1821
1822 if (!ok) HDEBUG(D_host_lookup)
1823 debug_printf("no IP address for %s matched %s\n", hname,
1824 sender_host_address);
1825 }
1826 else if (rc == HOST_FIND_AGAIN)
1827 {
1828 HDEBUG(D_host_lookup) debug_printf("temporary error for host name lookup\n");
1829 host_lookup_deferred = TRUE;
1830 sender_host_name = NULL;
1831 return DEFER;
1832 }
1833 else
1834 HDEBUG(D_host_lookup) debug_printf("no IP addresses found for %s\n", hname);
1835
1836 /* If this name is no good, and it's the sender name, set it null pro tem;
1837 if it's an alias, just remove it from the list. */
1838
1839 if (!ok)
1840 {
1841 if (hname == sender_host_name) sender_host_name = NULL; else
1842 {
1843 uschar **a; /* Don't amalgamate - some */
1844 a = --aliases; /* compilers grumble */
1845 while (*a != NULL) { *a = a[1]; a++; }
1846 }
1847 }
1848 }
1849
1850 /* If sender_host_name == NULL, it means we didn't like the name. Replace
1851 it with the first alias, if there is one. */
1852
1853 if (sender_host_name == NULL && *sender_host_aliases != NULL)
1854 sender_host_name = *sender_host_aliases++;
1855
1856 /* If we now have a main name, all is well. */
1857
1858 if (sender_host_name != NULL) return OK;
1859
1860 /* We have failed to find an address that matches. */
1861
1862 HDEBUG(D_host_lookup)
1863 debug_printf("%s does not match any IP address for %s\n",
1864 sender_host_address, save_hostname);
1865
1866 /* This message must be in permanent store */
1867
1868 old_pool = store_pool;
1869 store_pool = POOL_PERM;
1870 host_lookup_msg = string_sprintf(" (%s does not match any IP address for %s)",
1871 sender_host_address, save_hostname);
1872 store_pool = old_pool;
1873 host_lookup_failed = TRUE;
1874 return FAIL;
1875 }
1876
1877
1878
1879
1880 /*************************************************
1881 * Find IP address(es) for host by name *
1882 *************************************************/
1883
1884 /* The input is a host_item structure with the name filled in and the address
1885 field set to NULL. We use gethostbyname() or getipnodebyname() or
1886 gethostbyname2(), as appropriate. Of course, these functions may use the DNS,
1887 but they do not do MX processing. It appears, however, that in some systems the
1888 current setting of resolver options is used when one of these functions calls
1889 the resolver. For this reason, we call dns_init() at the start, with arguments
1890 influenced by bits in "flags", just as we do for host_find_bydns().
1891
1892 The second argument provides a host list (usually an IP list) of hosts to
1893 ignore. This makes it possible to ignore IPv6 link-local addresses or loopback
1894 addresses in unreasonable places.
1895
1896 The lookup may result in a change of name. For compatibility with the dns
1897 lookup, return this via fully_qualified_name as well as updating the host item.
1898 The lookup may also yield more than one IP address, in which case chain on
1899 subsequent host_item structures.
1900
1901 Arguments:
1902 host a host item with the name and MX filled in;
1903 the address is to be filled in;
1904 multiple IP addresses cause other host items to be
1905 chained on.
1906 ignore_target_hosts a list of hosts to ignore
1907 flags HOST_FIND_QUALIFY_SINGLE ) passed to
1908 HOST_FIND_SEARCH_PARENTS ) dns_init()
1909 fully_qualified_name if not NULL, set to point to host name for
1910 compatibility with host_find_bydns
1911 local_host_check TRUE if a check for the local host is wanted
1912
1913 Returns: HOST_FIND_FAILED Failed to find the host or domain
1914 HOST_FIND_AGAIN Try again later
1915 HOST_FOUND Host found - data filled in
1916 HOST_FOUND_LOCAL Host found and is the local host
1917 */
1918
1919 int
1920 host_find_byname(host_item *host, const uschar *ignore_target_hosts, int flags,
1921 const uschar **fully_qualified_name, BOOL local_host_check)
1922 {
1923 int i, yield, times;
1924 uschar **addrlist;
1925 host_item *last = NULL;
1926 BOOL temp_error = FALSE;
1927 #if HAVE_IPV6
1928 int af;
1929 #endif
1930
1931 /* If we are in the test harness, a name ending in .test.again.dns always
1932 forces a temporary error response, unless the name is in
1933 dns_again_means_nonexist. */
1934
1935 if (running_in_test_harness)
1936 {
1937 const uschar *endname = host->name + Ustrlen(host->name);
1938 if (Ustrcmp(endname - 14, "test.again.dns") == 0) goto RETURN_AGAIN;
1939 }
1940
1941 /* Make sure DNS options are set as required. This appears to be necessary in
1942 some circumstances when the get..byname() function actually calls the DNS. */
1943
1944 dns_init((flags & HOST_FIND_QUALIFY_SINGLE) != 0,
1945 (flags & HOST_FIND_SEARCH_PARENTS) != 0,
1946 FALSE); /* Cannot retrieve dnssec status so do not request */
1947
1948 /* In an IPv6 world, unless IPv6 has been disabled, we need to scan for both
1949 kinds of address, so go round the loop twice. Note that we have ensured that
1950 AF_INET6 is defined even in an IPv4 world, which makes for slightly tidier
1951 code. However, if dns_ipv4_lookup matches the domain, we also just do IPv4
1952 lookups here (except when testing standalone). */
1953
1954 #if HAVE_IPV6
1955 #ifdef STAND_ALONE
1956 if (disable_ipv6)
1957 #else
1958 if (disable_ipv6 ||
1959 (dns_ipv4_lookup != NULL &&
1960 match_isinlist(host->name, CUSS &dns_ipv4_lookup, 0, NULL, NULL,
1961 MCL_DOMAIN, TRUE, NULL) == OK))
1962 #endif
1963
1964 { af = AF_INET; times = 1; }
1965 else
1966 { af = AF_INET6; times = 2; }
1967
1968 /* No IPv6 support */
1969
1970 #else /* HAVE_IPV6 */
1971 times = 1;
1972 #endif /* HAVE_IPV6 */
1973
1974 /* Initialize the flag that gets set for DNS syntax check errors, so that the
1975 interface to this function can be similar to host_find_bydns. */
1976
1977 host_find_failed_syntax = FALSE;
1978
1979 /* Loop to look up both kinds of address in an IPv6 world */
1980
1981 for (i = 1; i <= times;
1982 #if HAVE_IPV6
1983 af = AF_INET, /* If 2 passes, IPv4 on the second */
1984 #endif
1985 i++)
1986 {
1987 BOOL ipv4_addr;
1988 int error_num = 0;
1989 struct hostent *hostdata;
1990 unsigned long time_msec;
1991
1992 #ifdef STAND_ALONE
1993 printf("Looking up: %s\n", host->name);
1994 #endif
1995
1996 if (slow_lookup_log) time_msec = get_time_in_ms();
1997
1998 #if HAVE_IPV6
1999 if (running_in_test_harness)
2000 hostdata = host_fake_gethostbyname(host->name, af, &error_num);
2001 else
2002 {
2003 #if HAVE_GETIPNODEBYNAME
2004 hostdata = getipnodebyname(CS host->name, af, 0, &error_num);
2005 #else
2006 hostdata = gethostbyname2(CS host->name, af);
2007 error_num = h_errno;
2008 #endif
2009 }
2010
2011 #else /* not HAVE_IPV6 */
2012 if (running_in_test_harness)
2013 hostdata = host_fake_gethostbyname(host->name, AF_INET, &error_num);
2014 else
2015 {
2016 hostdata = gethostbyname(CS host->name);
2017 error_num = h_errno;
2018 }
2019 #endif /* HAVE_IPV6 */
2020
2021 if (slow_lookup_log
2022 && (time_msec = get_time_in_ms() - time_msec) > slow_lookup_log)
2023 log_long_lookup(US"name", host->name, time_msec);
2024
2025 if (hostdata == NULL)
2026 {
2027 uschar *error;
2028 switch (error_num)
2029 {
2030 case HOST_NOT_FOUND: error = US"HOST_NOT_FOUND"; break;
2031 case TRY_AGAIN: error = US"TRY_AGAIN"; break;
2032 case NO_RECOVERY: error = US"NO_RECOVERY"; break;
2033 case NO_DATA: error = US"NO_DATA"; break;
2034 #if NO_DATA != NO_ADDRESS
2035 case NO_ADDRESS: error = US"NO_ADDRESS"; break;
2036 #endif
2037 default: error = US"?"; break;
2038 }
2039
2040 DEBUG(D_host_lookup) debug_printf("%s returned %d (%s)\n",
2041 #if HAVE_IPV6
2042 #if HAVE_GETIPNODEBYNAME
2043 (af == AF_INET6)? "getipnodebyname(af=inet6)" : "getipnodebyname(af=inet)",
2044 #else
2045 (af == AF_INET6)? "gethostbyname2(af=inet6)" : "gethostbyname2(af=inet)",
2046 #endif
2047 #else
2048 "gethostbyname",
2049 #endif
2050 error_num, error);
2051
2052 if (error_num == TRY_AGAIN || error_num == NO_RECOVERY) temp_error = TRUE;
2053 continue;
2054 }
2055 if ((hostdata->h_addr_list)[0] == NULL) continue;
2056
2057 /* Replace the name with the fully qualified one if necessary, and fill in
2058 the fully_qualified_name pointer. */
2059
2060 if (hostdata->h_name[0] != 0 &&
2061 Ustrcmp(host->name, hostdata->h_name) != 0)
2062 host->name = string_copy_dnsdomain((uschar *)hostdata->h_name);
2063 if (fully_qualified_name != NULL) *fully_qualified_name = host->name;
2064
2065 /* Get the list of addresses. IPv4 and IPv6 addresses can be distinguished
2066 by their different lengths. Scan the list, ignoring any that are to be
2067 ignored, and build a chain from the rest. */
2068
2069 ipv4_addr = hostdata->h_length == sizeof(struct in_addr);
2070
2071 for (addrlist = USS hostdata->h_addr_list; *addrlist != NULL; addrlist++)
2072 {
2073 uschar *text_address =
2074 host_ntoa(ipv4_addr? AF_INET:AF_INET6, *addrlist, NULL, NULL);
2075
2076 #ifndef STAND_ALONE
2077 if (ignore_target_hosts != NULL &&
2078 verify_check_this_host(&ignore_target_hosts, NULL, host->name,
2079 text_address, NULL) == OK)
2080 {
2081 DEBUG(D_host_lookup)
2082 debug_printf("ignored host %s [%s]\n", host->name, text_address);
2083 continue;
2084 }
2085 #endif
2086
2087 /* If this is the first address, last == NULL and we put the data in the
2088 original block. */
2089
2090 if (last == NULL)
2091 {
2092 host->address = text_address;
2093 host->port = PORT_NONE;
2094 host->status = hstatus_unknown;
2095 host->why = hwhy_unknown;
2096 host->dnssec = DS_UNK;
2097 last = host;
2098 }
2099
2100 /* Else add further host item blocks for any other addresses, keeping
2101 the order. */
2102
2103 else
2104 {
2105 host_item *next = store_get(sizeof(host_item));
2106 next->name = host->name;
2107 next->mx = host->mx;
2108 next->address = text_address;
2109 next->port = PORT_NONE;
2110 next->status = hstatus_unknown;
2111 next->why = hwhy_unknown;
2112 next->dnssec = DS_UNK;
2113 next->last_try = 0;
2114 next->next = last->next;
2115 last->next = next;
2116 last = next;
2117 }
2118 }
2119 }
2120
2121 /* If no hosts were found, the address field in the original host block will be
2122 NULL. If temp_error is set, at least one of the lookups gave a temporary error,
2123 so we pass that back. */
2124
2125 if (host->address == NULL)
2126 {
2127 uschar *msg =
2128 #ifndef STAND_ALONE
2129 (message_id[0] == 0 && smtp_in != NULL)?
2130 string_sprintf("no IP address found for host %s (during %s)", host->name,
2131 smtp_get_connection_info()) :
2132 #endif
2133 string_sprintf("no IP address found for host %s", host->name);
2134
2135 HDEBUG(D_host_lookup) debug_printf("%s\n", msg);
2136 if (temp_error) goto RETURN_AGAIN;
2137 if (host_checking || !log_testing_mode)
2138 log_write(L_host_lookup_failed, LOG_MAIN, "%s", msg);
2139 return HOST_FIND_FAILED;
2140 }
2141
2142 /* Remove any duplicate IP addresses, then check to see if this is the local
2143 host if required. */
2144
2145 host_remove_duplicates(host, &last);
2146 yield = local_host_check?
2147 host_scan_for_local_hosts(host, &last, NULL) : HOST_FOUND;
2148
2149 HDEBUG(D_host_lookup)
2150 {
2151 const host_item *h;
2152 if (fully_qualified_name != NULL)
2153 debug_printf("fully qualified name = %s\n", *fully_qualified_name);
2154 debug_printf("%s looked up these IP addresses:\n",
2155 #if HAVE_IPV6
2156 #if HAVE_GETIPNODEBYNAME
2157 "getipnodebyname"
2158 #else
2159 "gethostbyname2"
2160 #endif
2161 #else
2162 "gethostbyname"
2163 #endif
2164 );
2165 for (h = host; h != last->next; h = h->next)
2166 debug_printf(" name=%s address=%s\n", h->name,
2167 (h->address == NULL)? US"<null>" : h->address);
2168 }
2169
2170 /* Return the found status. */
2171
2172 return yield;
2173
2174 /* Handle the case when there is a temporary error. If the name matches
2175 dns_again_means_nonexist, return permanent rather than temporary failure. */
2176
2177 RETURN_AGAIN:
2178 {
2179 #ifndef STAND_ALONE
2180 int rc;
2181 const uschar *save = deliver_domain;
2182 deliver_domain = host->name; /* set $domain */
2183 rc = match_isinlist(host->name, CUSS &dns_again_means_nonexist, 0, NULL, NULL,
2184 MCL_DOMAIN, TRUE, NULL);
2185 deliver_domain = save;
2186 if (rc == OK)
2187 {
2188 DEBUG(D_host_lookup) debug_printf("%s is in dns_again_means_nonexist: "
2189 "returning HOST_FIND_FAILED\n", host->name);
2190 return HOST_FIND_FAILED;
2191 }
2192 #endif
2193 return HOST_FIND_AGAIN;
2194 }
2195 }
2196
2197
2198
2199 /*************************************************
2200 * Fill in a host address from the DNS *
2201 *************************************************/
2202
2203 /* Given a host item, with its name, port and mx fields set, and its address
2204 field set to NULL, fill in its IP address from the DNS. If it is multi-homed,
2205 create additional host items for the additional addresses, copying all the
2206 other fields, and randomizing the order.
2207
2208 On IPv6 systems, A6 records are sought first (but only if support for A6 is
2209 configured - they may never become mainstream), then AAAA records are sought,
2210 and finally A records are sought as well.
2211
2212 The host name may be changed if the DNS returns a different name - e.g. fully
2213 qualified or changed via CNAME. If fully_qualified_name is not NULL, dns_lookup
2214 ensures that it points to the fully qualified name. However, this is the fully
2215 qualified version of the original name; if a CNAME is involved, the actual
2216 canonical host name may be different again, and so we get it directly from the
2217 relevant RR. Note that we do NOT change the mx field of the host item in this
2218 function as it may be called to set the addresses of hosts taken from MX
2219 records.
2220
2221 Arguments:
2222 host points to the host item we're filling in
2223 lastptr points to pointer to last host item in a chain of
2224 host items (may be updated if host is last and gets
2225 extended because multihomed)
2226 ignore_target_hosts list of hosts to ignore
2227 allow_ip if TRUE, recognize an IP address and return it
2228 fully_qualified_name if not NULL, return fully qualified name here if
2229 the contents are different (i.e. it must be preset
2230 to something)
2231 dnnssec_require if TRUE check the DNS result AD bit
2232
2233 Returns: HOST_FIND_FAILED couldn't find A record
2234 HOST_FIND_AGAIN try again later
2235 HOST_FOUND found AAAA and/or A record(s)
2236 HOST_IGNORED found, but all IPs ignored
2237 */
2238
2239 static int
2240 set_address_from_dns(host_item *host, host_item **lastptr,
2241 const uschar *ignore_target_hosts, BOOL allow_ip,
2242 const uschar **fully_qualified_name,
2243 BOOL dnssec_request, BOOL dnssec_require)
2244 {
2245 dns_record *rr;
2246 host_item *thishostlast = NULL; /* Indicates not yet filled in anything */
2247 BOOL v6_find_again = FALSE;
2248 int i;
2249
2250 /* If allow_ip is set, a name which is an IP address returns that value
2251 as its address. This is used for MX records when allow_mx_to_ip is set, for
2252 those sites that feel they have to flaunt the RFC rules. */
2253
2254 if (allow_ip && string_is_ip_address(host->name, NULL) != 0)
2255 {
2256 #ifndef STAND_ALONE
2257 if (ignore_target_hosts != NULL &&
2258 verify_check_this_host(&ignore_target_hosts, NULL, host->name,
2259 host->name, NULL) == OK)
2260 return HOST_IGNORED;
2261 #endif
2262
2263 host->address = host->name;
2264 return HOST_FOUND;
2265 }
2266
2267 /* On an IPv6 system, unless IPv6 is disabled, go round the loop up to three
2268 times, looking for A6 and AAAA records the first two times. However, unless
2269 doing standalone testing, we force an IPv4 lookup if the domain matches
2270 dns_ipv4_lookup is set. Since A6 records look like being abandoned, support
2271 them only if explicitly configured to do so. On an IPv4 system, go round the
2272 loop once only, looking only for A records. */
2273
2274 #if HAVE_IPV6
2275 #ifndef STAND_ALONE
2276 if (disable_ipv6 || (dns_ipv4_lookup != NULL &&
2277 match_isinlist(host->name, CUSS &dns_ipv4_lookup, 0, NULL, NULL,
2278 MCL_DOMAIN, TRUE, NULL) == OK))
2279 i = 0; /* look up A records only */
2280 else
2281 #endif /* STAND_ALONE */
2282
2283 i = 1; /* look up AAAA and A records */
2284
2285 /* The IPv4 world */
2286
2287 #else /* HAVE_IPV6 */
2288 i = 0; /* look up A records only */
2289 #endif /* HAVE_IPV6 */
2290
2291 for (; i >= 0; i--)
2292 {
2293 static int types[] = { T_A, T_AAAA, T_A6 };
2294 int type = types[i];
2295 int randoffset = (i == 0)? 500 : 0; /* Ensures v6 sorts before v4 */
2296 dns_answer dnsa;
2297 dns_scan dnss;
2298
2299 int rc = dns_lookup_timerwrap(&dnsa, host->name, type, fully_qualified_name);
2300 lookup_dnssec_authenticated = !dnssec_request ? NULL
2301 : dns_is_secure(&dnsa) ? US"yes" : US"no";
2302
2303 /* We want to return HOST_FIND_AGAIN if one of the A, A6, or AAAA lookups
2304 fails or times out, but not if another one succeeds. (In the early
2305 IPv6 days there are name servers that always fail on AAAA, but are happy
2306 to give out an A record. We want to proceed with that A record.) */
2307
2308 if (rc != DNS_SUCCEED)
2309 {
2310 if (i == 0) /* Just tried for an A record, i.e. end of loop */
2311 {
2312 if (host->address != NULL) return HOST_FOUND; /* A6 or AAAA was found */
2313 if (rc == DNS_AGAIN || rc == DNS_FAIL || v6_find_again)
2314 return HOST_FIND_AGAIN;
2315 return HOST_FIND_FAILED; /* DNS_NOMATCH or DNS_NODATA */
2316 }
2317
2318 /* Tried for an A6 or AAAA record: remember if this was a temporary
2319 error, and look for the next record type. */
2320
2321 if (rc != DNS_NOMATCH && rc != DNS_NODATA) v6_find_again = TRUE;
2322 continue;
2323 }
2324
2325 if (dnssec_request)
2326 {
2327 if (dns_is_secure(&dnsa))
2328 {
2329 DEBUG(D_host_lookup) debug_printf("%s A DNSSEC\n", host->name);
2330 if (host->dnssec == DS_UNK) /* set in host_find_bydns() */
2331 host->dnssec = DS_YES;
2332 }
2333 else
2334 {
2335 if (dnssec_require)
2336 {
2337 log_write(L_host_lookup_failed, LOG_MAIN,
2338 "dnssec fail on %s for %.256s",
2339 i>1 ? "A6" : i>0 ? "AAAA" : "A", host->name);
2340 continue;
2341 }
2342 if (host->dnssec == DS_YES) /* set in host_find_bydns() */
2343 {
2344 DEBUG(D_host_lookup) debug_printf("%s A cancel DNSSEC\n", host->name);
2345 host->dnssec = DS_NO;
2346 lookup_dnssec_authenticated = US"no";
2347 }
2348 }
2349 }
2350
2351 /* Lookup succeeded: fill in the given host item with the first non-ignored
2352 address found; create additional items for any others. A single A6 record
2353 may generate more than one address. The lookup had a chance to update the
2354 fqdn; we do not want any later times round the loop to do so. */
2355
2356 fully_qualified_name = NULL;
2357
2358 for (rr = dns_next_rr(&dnsa, &dnss, RESET_ANSWERS);
2359 rr;
2360 rr = dns_next_rr(&dnsa, &dnss, RESET_NEXT))
2361 {
2362 if (rr->type == type)
2363 {
2364 /* dns_address *da = dns_address_from_rr(&dnsa, rr); */
2365
2366 dns_address *da;
2367 da = dns_address_from_rr(&dnsa, rr);
2368
2369 DEBUG(D_host_lookup)
2370 {
2371 if (!da) debug_printf("no addresses extracted from A6 RR for %s\n",
2372 host->name);
2373 }
2374
2375 /* This loop runs only once for A and AAAA records, but may run
2376 several times for an A6 record that generated multiple addresses. */
2377
2378 for (; da; da = da->next)
2379 {
2380 #ifndef STAND_ALONE
2381 if (ignore_target_hosts != NULL &&
2382 verify_check_this_host(&ignore_target_hosts, NULL,
2383 host->name, da->address, NULL) == OK)
2384 {
2385 DEBUG(D_host_lookup)
2386 debug_printf("ignored host %s [%s]\n", host->name, da->address);
2387 continue;
2388 }
2389 #endif
2390
2391 /* If this is the first address, stick it in the given host block,
2392 and change the name if the returned RR has a different name. */
2393
2394 if (thishostlast == NULL)
2395 {
2396 if (strcmpic(host->name, rr->name) != 0)
2397 host->name = string_copy_dnsdomain(rr->name);
2398 host->address = da->address;
2399 host->sort_key = host->mx * 1000 + random_number(500) + randoffset;
2400 host->status = hstatus_unknown;
2401 host->why = hwhy_unknown;
2402 thishostlast = host;
2403 }
2404
2405 /* Not the first address. Check for, and ignore, duplicates. Then
2406 insert in the chain at a random point. */
2407
2408 else
2409 {
2410 int new_sort_key;
2411 host_item *next;
2412
2413 /* End of our local chain is specified by "thishostlast". */
2414
2415 for (next = host;; next = next->next)
2416 {
2417 if (Ustrcmp(CS da->address, next->address) == 0) break;
2418 if (next == thishostlast) { next = NULL; break; }
2419 }
2420 if (next != NULL) continue; /* With loop for next address */
2421
2422 /* Not a duplicate */
2423
2424 new_sort_key = host->mx * 1000 + random_number(500) + randoffset;
2425 next = store_get(sizeof(host_item));
2426
2427 /* New address goes first: insert the new block after the first one
2428 (so as not to disturb the original pointer) but put the new address
2429 in the original block. */
2430
2431 if (new_sort_key < host->sort_key)
2432 {
2433 *next = *host; /* Copies port */
2434 host->next = next;
2435 host->address = da->address;
2436 host->sort_key = new_sort_key;
2437 if (thishostlast == host) thishostlast = next; /* Local last */
2438 if (*lastptr == host) *lastptr = next; /* Global last */
2439 }
2440
2441 /* Otherwise scan down the addresses for this host to find the
2442 one to insert after. */
2443
2444 else
2445 {
2446 host_item *h = host;
2447 while (h != thishostlast)
2448 {
2449 if (new_sort_key < h->next->sort_key) break;
2450 h = h->next;
2451 }
2452 *next = *h; /* Copies port */
2453 h->next = next;
2454 next->address = da->address;
2455 next->sort_key = new_sort_key;
2456 if (h == thishostlast) thishostlast = next; /* Local last */
2457 if (h == *lastptr) *lastptr = next; /* Global last */
2458 }
2459 }
2460 }
2461 }
2462 }
2463 }
2464
2465 /* Control gets here only if the third lookup (the A record) succeeded.
2466 However, the address may not be filled in if it was ignored. */
2467
2468 return (host->address == NULL)? HOST_IGNORED : HOST_FOUND;
2469 }
2470
2471
2472
2473
2474 /*************************************************
2475 * Find IP addresses and host names via DNS *
2476 *************************************************/
2477
2478 /* The input is a host_item structure with the name field filled in and the
2479 address field set to NULL. This may be in a chain of other host items. The
2480 lookup may result in more than one IP address, in which case we must created
2481 new host blocks for the additional addresses, and insert them into the chain.
2482 The original name may not be fully qualified. Use the fully_qualified_name
2483 argument to return the official name, as returned by the resolver.
2484
2485 Arguments:
2486 host point to initial host item
2487 ignore_target_hosts a list of hosts to ignore
2488 whichrrs flags indicating which RRs to look for:
2489 HOST_FIND_BY_SRV => look for SRV
2490 HOST_FIND_BY_MX => look for MX
2491 HOST_FIND_BY_A => look for A or AAAA
2492 also flags indicating how the lookup is done
2493 HOST_FIND_QUALIFY_SINGLE ) passed to the
2494 HOST_FIND_SEARCH_PARENTS ) resolver
2495 srv_service when SRV used, the service name
2496 srv_fail_domains DNS errors for these domains => assume nonexist
2497 mx_fail_domains DNS errors for these domains => assume nonexist
2498 dnssec_d.request => make dnssec request: domainlist
2499 dnssec_d.require => ditto and nonexist failures
2500 fully_qualified_name if not NULL, return fully-qualified name
2501 removed set TRUE if local host was removed from the list
2502
2503 Returns: HOST_FIND_FAILED Failed to find the host or domain;
2504 if there was a syntax error,
2505 host_find_failed_syntax is set.
2506 HOST_FIND_AGAIN Could not resolve at this time
2507 HOST_FOUND Host found
2508 HOST_FOUND_LOCAL The lowest MX record points to this
2509 machine, if MX records were found, or
2510 an A record that was found contains
2511 an address of the local host
2512 */
2513
2514 int
2515 host_find_bydns(host_item *host, const uschar *ignore_target_hosts, int whichrrs,
2516 uschar *srv_service, uschar *srv_fail_domains, uschar *mx_fail_domains,
2517 const dnssec_domains *dnssec_d,
2518 const uschar **fully_qualified_name, BOOL *removed)
2519 {
2520 host_item *h, *last;
2521 dns_record *rr;
2522 int rc = DNS_FAIL;
2523 int ind_type = 0;
2524 int yield;
2525 dns_answer dnsa;
2526 dns_scan dnss;
2527 BOOL dnssec_require = dnssec_d
2528 && match_isinlist(host->name, CUSS &dnssec_d->require,
2529 0, NULL, NULL, MCL_DOMAIN, TRUE, NULL) == OK;
2530 BOOL dnssec_request = dnssec_require
2531 || ( dnssec_d
2532 && match_isinlist(host->name, CUSS &dnssec_d->request,
2533 0, NULL, NULL, MCL_DOMAIN, TRUE, NULL) == OK);
2534 dnssec_status_t dnssec;
2535
2536 /* Set the default fully qualified name to the incoming name, initialize the
2537 resolver if necessary, set up the relevant options, and initialize the flag
2538 that gets set for DNS syntax check errors. */
2539
2540 if (fully_qualified_name != NULL) *fully_qualified_name = host->name;
2541 dns_init((whichrrs & HOST_FIND_QUALIFY_SINGLE) != 0,
2542 (whichrrs & HOST_FIND_SEARCH_PARENTS) != 0,
2543 dnssec_request);
2544 host_find_failed_syntax = FALSE;
2545
2546 /* First, if requested, look for SRV records. The service name is given; we
2547 assume TCP progocol. DNS domain names are constrained to a maximum of 256
2548 characters, so the code below should be safe. */
2549
2550 if ((whichrrs & HOST_FIND_BY_SRV) != 0)
2551 {
2552 uschar buffer[300];
2553 uschar *temp_fully_qualified_name = buffer;
2554 int prefix_length;
2555
2556 (void)sprintf(CS buffer, "_%s._tcp.%n%.256s", srv_service, &prefix_length,
2557 host->name);
2558 ind_type = T_SRV;
2559
2560 /* Search for SRV records. If the fully qualified name is different to
2561 the input name, pass back the new original domain, without the prepended
2562 magic. */
2563
2564 dnssec = DS_UNK;
2565 lookup_dnssec_authenticated = NULL;
2566 rc = dns_lookup_timerwrap(&dnsa, buffer, ind_type, CUSS &temp_fully_qualified_name);
2567
2568 if (dnssec_request)
2569 {
2570 if (dns_is_secure(&dnsa))
2571 { dnssec = DS_YES; lookup_dnssec_authenticated = US"yes"; }
2572 else
2573 { dnssec = DS_NO; lookup_dnssec_authenticated = US"no"; }
2574 }
2575
2576 if (temp_fully_qualified_name != buffer && fully_qualified_name != NULL)
2577 *fully_qualified_name = temp_fully_qualified_name + prefix_length;
2578
2579 /* On DNS failures, we give the "try again" error unless the domain is
2580 listed as one for which we continue. */
2581
2582 if (rc == DNS_SUCCEED && dnssec_require && !dns_is_secure(&dnsa))
2583 {
2584 log_write(L_host_lookup_failed, LOG_MAIN,
2585 "dnssec fail on SRV for %.256s", host->name);
2586 rc = DNS_FAIL;
2587 }
2588 if (rc == DNS_FAIL || rc == DNS_AGAIN)
2589 {
2590 #ifndef STAND_ALONE
2591 if (match_isinlist(host->name, CUSS &srv_fail_domains, 0, NULL, NULL,
2592 MCL_DOMAIN, TRUE, NULL) != OK)
2593 #endif
2594 { yield = HOST_FIND_AGAIN; goto out; }
2595 DEBUG(D_host_lookup) debug_printf("DNS_%s treated as DNS_NODATA "
2596 "(domain in srv_fail_domains)\n", (rc == DNS_FAIL)? "FAIL":"AGAIN");
2597 }
2598 }
2599
2600 /* If we did not find any SRV records, search the DNS for MX records, if
2601 requested to do so. If the result is DNS_NOMATCH, it means there is no such
2602 domain, and there's no point in going on to look for address records with the
2603 same domain. The result will be DNS_NODATA if the domain exists but has no MX
2604 records. On DNS failures, we give the "try again" error unless the domain is
2605 listed as one for which we continue. */
2606
2607 if (rc != DNS_SUCCEED && (whichrrs & HOST_FIND_BY_MX) != 0)
2608 {
2609 ind_type = T_MX;
2610 dnssec = DS_UNK;
2611 lookup_dnssec_authenticated = NULL;
2612 rc = dns_lookup_timerwrap(&dnsa, host->name, ind_type, fully_qualified_name);
2613
2614 if (dnssec_request)
2615 {
2616 if (dns_is_secure(&dnsa))
2617 {
2618 DEBUG(D_host_lookup) debug_printf("%s MX DNSSEC\n", host->name);
2619 dnssec = DS_YES; lookup_dnssec_authenticated = US"yes";
2620 }
2621 else
2622 {
2623 dnssec = DS_NO; lookup_dnssec_authenticated = US"no";
2624 }
2625 }
2626
2627 switch (rc)
2628 {
2629 case DNS_NOMATCH:
2630 yield = HOST_FIND_FAILED; goto out;
2631
2632 case DNS_SUCCEED:
2633 if (!dnssec_require || dns_is_secure(&dnsa))
2634 break;
2635 log_write(L_host_lookup_failed, LOG_MAIN,
2636 "dnssec fail on MX for %.256s", host->name);
2637 rc = DNS_FAIL;
2638 /*FALLTHROUGH*/
2639
2640 case DNS_FAIL:
2641 case DNS_AGAIN:
2642 #ifndef STAND_ALONE
2643 if (match_isinlist(host->name, CUSS &mx_fail_domains, 0, NULL, NULL,
2644 MCL_DOMAIN, TRUE, NULL) != OK)
2645 #endif
2646 { yield = HOST_FIND_AGAIN; goto out; }
2647 DEBUG(D_host_lookup) debug_printf("DNS_%s treated as DNS_NODATA "
2648 "(domain in mx_fail_domains)\n", (rc == DNS_FAIL)? "FAIL":"AGAIN");
2649 break;
2650 }
2651 }
2652
2653 /* If we haven't found anything yet, and we are requested to do so, try for an
2654 A or AAAA record. If we find it (or them) check to see that it isn't the local
2655 host. */
2656
2657 if (rc != DNS_SUCCEED)
2658 {
2659 if ((whichrrs & HOST_FIND_BY_A) == 0)
2660 {
2661 DEBUG(D_host_lookup) debug_printf("Address records are not being sought\n");
2662 yield = HOST_FIND_FAILED;
2663 goto out;
2664 }
2665
2666 last = host; /* End of local chainlet */
2667 host->mx = MX_NONE;
2668 host->port = PORT_NONE;
2669 host->dnssec = DS_UNK;
2670 lookup_dnssec_authenticated = NULL;
2671 rc = set_address_from_dns(host, &last, ignore_target_hosts, FALSE,
2672 fully_qualified_name, dnssec_request, dnssec_require);
2673
2674 /* If one or more address records have been found, check that none of them
2675 are local. Since we know the host items all have their IP addresses
2676 inserted, host_scan_for_local_hosts() can only return HOST_FOUND or
2677 HOST_FOUND_LOCAL. We do not need to scan for duplicate IP addresses here,
2678 because set_address_from_dns() removes them. */
2679
2680 if (rc == HOST_FOUND)
2681 rc = host_scan_for_local_hosts(host, &last, removed);
2682 else
2683 if (rc == HOST_IGNORED) rc = HOST_FIND_FAILED; /* No special action */
2684
2685 DEBUG(D_host_lookup)
2686 {
2687 host_item *h;
2688 if (host->address != NULL)
2689 {
2690 if (fully_qualified_name != NULL)
2691 debug_printf("fully qualified name = %s\n", *fully_qualified_name);
2692 for (h = host; h != last->next; h = h->next)
2693 debug_printf("%s %s mx=%d sort=%d %s\n", h->name,
2694 (h->address == NULL)? US"<null>" : h->address, h->mx, h->sort_key,
2695 (h->status >= hstatus_unusable)? US"*" : US"");
2696 }
2697 }
2698
2699 yield = rc;
2700 goto out;
2701 }
2702
2703 /* We have found one or more MX or SRV records. Sort them according to
2704 precedence. Put the data for the first one into the existing host block, and
2705 insert new host_item blocks into the chain for the remainder. For equal
2706 precedences one is supposed to randomize the order. To make this happen, the
2707 sorting is actually done on the MX value * 1000 + a random number. This is put
2708 into a host field called sort_key.
2709
2710 In the case of hosts with both IPv6 and IPv4 addresses, we want to choose the
2711 IPv6 address in preference. At this stage, we don't know what kind of address
2712 the host has. We choose a random number < 500; if later we find an A record
2713 first, we add 500 to the random number. Then for any other address records, we
2714 use random numbers in the range 0-499 for AAAA records and 500-999 for A
2715 records.
2716
2717 At this point we remove any duplicates that point to the same host, retaining
2718 only the one with the lowest precedence. We cannot yet check for precedence
2719 greater than that of the local host, because that test cannot be properly done
2720 until the addresses have been found - an MX record may point to a name for this
2721 host which is not the primary hostname. */
2722
2723 last = NULL; /* Indicates that not even the first item is filled yet */
2724
2725 for (rr = dns_next_rr(&dnsa, &dnss, RESET_ANSWERS);
2726 rr != NULL;
2727 rr = dns_next_rr(&dnsa, &dnss, RESET_NEXT))
2728 {
2729 int precedence;
2730 int weight = 0; /* For SRV records */
2731 int port = PORT_NONE;
2732 uschar *s; /* MUST be unsigned for GETSHORT */
2733 uschar data[256];
2734
2735 if (rr->type != ind_type) continue;
2736 s = rr->data;
2737 GETSHORT(precedence, s); /* Pointer s is advanced */
2738
2739 /* For MX records, we use a random "weight" which causes multiple records of
2740 the same precedence to sort randomly. */
2741
2742 if (ind_type == T_MX)
2743 weight = random_number(500);
2744
2745 /* SRV records are specified with a port and a weight. The weight is used
2746 in a special algorithm. However, to start with, we just use it to order the
2747 records of equal priority (precedence). */
2748
2749 else
2750 {
2751 GETSHORT(weight, s);
2752 GETSHORT(port, s);
2753 }
2754
2755 /* Get the name of the host pointed to. */
2756
2757 (void)dn_expand(dnsa.answer, dnsa.answer + dnsa.answerlen, s,
2758 (DN_EXPAND_ARG4_TYPE)data, sizeof(data));
2759
2760 /* Check that we haven't already got this host on the chain; if we have,
2761 keep only the lower precedence. This situation shouldn't occur, but you
2762 never know what junk might get into the DNS (and this case has been seen on
2763 more than one occasion). */
2764
2765 if (last != NULL) /* This is not the first record */
2766 {
2767 host_item *prev = NULL;
2768
2769 for (h = host; h != last->next; prev = h, h = h->next)
2770 {
2771 if (strcmpic(h->name, data) == 0)
2772 {
2773 DEBUG(D_host_lookup)
2774 debug_printf("discarded duplicate host %s (MX=%d)\n", data,
2775 (precedence > h->mx)? precedence : h->mx);
2776 if (precedence >= h->mx) goto NEXT_MX_RR; /* Skip greater precedence */
2777 if (h == host) /* Override first item */
2778 {
2779 h->mx = precedence;
2780 host->sort_key = precedence * 1000 + weight;
2781 goto NEXT_MX_RR;
2782 }
2783
2784 /* Unwanted host item is not the first in the chain, so we can get
2785 get rid of it by cutting it out. */
2786
2787 prev->next = h->next;
2788 if (h == last) last = prev;
2789 break;
2790 }
2791 }
2792 }
2793
2794 /* If this is the first MX or SRV record, put the data into the existing host
2795 block. Otherwise, add a new block in the correct place; if it has to be
2796 before the first block, copy the first block's data to a new second block. */
2797
2798 if (last == NULL)
2799 {
2800 host->name = string_copy_dnsdomain(data);
2801 host->address = NULL;
2802 host->port = port;
2803 host->mx = precedence;
2804 host->sort_key = precedence * 1000 + weight;
2805 host->status = hstatus_unknown;
2806 host->why = hwhy_unknown;
2807 host->dnssec = dnssec;
2808 last = host;
2809 }
2810
2811 /* Make a new host item and seek the correct insertion place */
2812
2813 else
2814 {
2815 int sort_key = precedence * 1000 + weight;
2816 host_item *next = store_get(sizeof(host_item));
2817 next->name = string_copy_dnsdomain(data);
2818 next->address = NULL;
2819 next->port = port;
2820 next->mx = precedence;
2821 next->sort_key = sort_key;
2822 next->status = hstatus_unknown;
2823 next->why = hwhy_unknown;
2824 next->dnssec = dnssec;
2825 next->last_try = 0;
2826
2827 /* Handle the case when we have to insert before the first item. */
2828
2829 if (sort_key < host->sort_key)
2830 {
2831 host_item htemp;
2832 htemp = *host;
2833 *host = *next;
2834 *next = htemp;
2835 host->next = next;
2836 if (last == host) last = next;
2837 }
2838
2839 /* Else scan down the items we have inserted as part of this exercise;
2840 don't go further. */
2841
2842 else
2843 {
2844 for (h = host; h != last; h = h->next)
2845 {
2846 if (sort_key < h->next->sort_key)
2847 {
2848 next->next = h->next;
2849 h->next = next;
2850 break;
2851 }
2852 }
2853
2854 /* Join on after the last host item that's part of this
2855 processing if we haven't stopped sooner. */
2856
2857 if (h == last)
2858 {
2859 next->next = last->next;
2860 last->next = next;
2861 last = next;
2862 }
2863 }
2864 }
2865
2866 NEXT_MX_RR: continue;
2867 }
2868
2869 /* If the list of hosts was obtained from SRV records, there are two things to
2870 do. First, if there is only one host, and it's name is ".", it means there is
2871 no SMTP service at this domain. Otherwise, we have to sort the hosts of equal
2872 priority according to their weights, using an algorithm that is defined in RFC
2873 2782. The hosts are currently sorted by priority and weight. For each priority
2874 group we have to pick off one host and put it first, and then repeat for any
2875 remaining in the same priority group. */
2876
2877 if (ind_type == T_SRV)
2878 {
2879 host_item **pptr;
2880
2881 if (host == last && host->name[0] == 0)
2882 {
2883 DEBUG(D_host_lookup) debug_printf("the single SRV record is \".\"\n");
2884 yield = HOST_FIND_FAILED;
2885 goto out;
2886 }
2887
2888 DEBUG(D_host_lookup)
2889 {
2890 debug_printf("original ordering of hosts from SRV records:\n");
2891 for (h = host; h != last->next; h = h->next)
2892 debug_printf(" %s P=%d W=%d\n", h->name, h->mx, h->sort_key % 1000);
2893 }
2894
2895 for (pptr = &host, h = host; h != last; pptr = &(h->next), h = h->next)
2896 {
2897 int sum = 0;
2898 host_item *hh;
2899
2900 /* Find the last following host that has the same precedence. At the same
2901 time, compute the sum of the weights and the running totals. These can be
2902 stored in the sort_key field. */
2903
2904 for (hh = h; hh != last; hh = hh->next)
2905 {
2906 int weight = hh->sort_key % 1000; /* was precedence * 1000 + weight */
2907 sum += weight;
2908 hh->sort_key = sum;
2909 if (hh->mx != hh->next->mx) break;
2910 }
2911
2912 /* If there's more than one host at this precedence (priority), we need to
2913 pick one to go first. */
2914
2915 if (hh != h)
2916 {
2917 host_item *hhh;
2918 host_item **ppptr;
2919 int randomizer = random_number(sum + 1);
2920
2921 for (ppptr = pptr, hhh = h;
2922 hhh != hh;
2923 ppptr = &(hhh->next), hhh = hhh->next)
2924 {
2925 if (hhh->sort_key >= randomizer) break;
2926 }
2927
2928 /* hhh now points to the host that should go first; ppptr points to the
2929 place that points to it. Unfortunately, if the start of the minilist is
2930 the start of the entire list, we can't just swap the items over, because
2931 we must not change the value of host, since it is passed in from outside.
2932 One day, this could perhaps be changed.
2933
2934 The special case is fudged by putting the new item *second* in the chain,
2935 and then transferring the data between the first and second items. We
2936 can't just swap the first and the chosen item, because that would mean
2937 that an item with zero weight might no longer be first. */
2938
2939 if (hhh != h)
2940 {
2941 *ppptr = hhh->next; /* Cuts it out of the chain */
2942
2943 if (h == host)
2944 {
2945 host_item temp = *h;
2946 *h = *hhh;
2947 *hhh = temp;
2948 hhh->next = temp.next;
2949 h->next = hhh;
2950 }
2951
2952 else
2953 {
2954 hhh->next = h; /* The rest of the chain follows it */
2955 *pptr = hhh; /* It takes the place of h */
2956 h = hhh; /* It's now the start of this minilist */
2957 }
2958 }
2959 }
2960
2961 /* A host has been chosen to be first at this priority and h now points
2962 to this host. There may be others at the same priority, or others at a
2963 different priority. Before we leave this host, we need to put back a sort
2964 key of the traditional MX kind, in case this host is multihomed, because
2965 the sort key is used for ordering the multiple IP addresses. We do not need
2966 to ensure that these new sort keys actually reflect the order of the hosts,
2967 however. */
2968
2969 h->sort_key = h->mx * 1000 + random_number(500);
2970 } /* Move on to the next host */
2971 }
2972
2973 /* Now we have to find IP addresses for all the hosts. We have ensured above
2974 that the names in all the host items are unique. Before release 4.61 we used to
2975 process records from the additional section in the DNS packet that returned the
2976 MX or SRV records. However, a DNS name server is free to drop any resource
2977 records from the additional section. In theory, this has always been a
2978 potential problem, but it is exacerbated by the advent of IPv6. If a host had
2979 several IPv4 addresses and some were not in the additional section, at least
2980 Exim would try the others. However, if a host had both IPv4 and IPv6 addresses
2981 and all the IPv4 (say) addresses were absent, Exim would try only for a IPv6
2982 connection, and never try an IPv4 address. When there was only IPv4
2983 connectivity, this was a disaster that did in practice occur.
2984
2985 So, from release 4.61 onwards, we always search for A and AAAA records
2986 explicitly. The names shouldn't point to CNAMES, but we use the general lookup
2987 function that handles them, just in case. If any lookup gives a soft error,
2988 change the default yield.
2989
2990 For these DNS lookups, we must disable qualify_single and search_parents;
2991 otherwise invalid host names obtained from MX or SRV records can cause trouble
2992 if they happen to match something local. */
2993
2994 yield = HOST_FIND_FAILED; /* Default yield */
2995 dns_init(FALSE, FALSE, /* Disable qualify_single and search_parents */
2996 dnssec_request || dnssec_require);
2997
2998 for (h = host; h != last->next; h = h->next)
2999 {
3000 if (h->address != NULL) continue; /* Inserted by a multihomed host */
3001 rc = set_address_from_dns(h, &last, ignore_target_hosts, allow_mx_to_ip,
3002 NULL, dnssec_request, dnssec_require);
3003 if (rc != HOST_FOUND)
3004 {
3005 h->status = hstatus_unusable;
3006 if (rc == HOST_FIND_AGAIN)
3007 {
3008 yield = rc;
3009 h->why = hwhy_deferred;
3010 }
3011 else
3012 h->why = (rc == HOST_IGNORED)? hwhy_ignored : hwhy_failed;
3013 }
3014 }
3015
3016 /* Scan the list for any hosts that are marked unusable because they have
3017 been explicitly ignored, and remove them from the list, as if they did not
3018 exist. If we end up with just a single, ignored host, flatten its fields as if
3019 nothing was found. */
3020
3021 if (ignore_target_hosts != NULL)
3022 {
3023 host_item *prev = NULL;
3024 for (h = host; h != last->next; h = h->next)
3025 {
3026 REDO:
3027 if (h->why != hwhy_ignored) /* Non ignored host, just continue */
3028 prev = h;
3029 else if (prev == NULL) /* First host is ignored */
3030 {
3031 if (h != last) /* First is not last */
3032 {
3033 if (h->next == last) last = h; /* Overwrite it with next */
3034 *h = *(h->next); /* and reprocess it. */
3035 goto REDO; /* C should have redo, like Perl */
3036 }
3037 }
3038 else /* Ignored host is not first - */
3039 { /* cut it out */
3040 prev->next = h->next;
3041 if (h == last) last = prev;
3042 }
3043 }
3044
3045 if (host->why == hwhy_ignored) host->address = NULL;
3046 }
3047
3048 /* There is still one complication in the case of IPv6. Although the code above
3049 arranges that IPv6 addresses take precedence over IPv4 addresses for multihomed
3050 hosts, it doesn't do this for addresses that apply to different hosts with the
3051 same MX precedence, because the sorting on MX precedence happens first. So we
3052 have to make another pass to check for this case. We ensure that, within a
3053 single MX preference value, IPv6 addresses come first. This can separate the
3054 addresses of a multihomed host, but that should not matter. */
3055
3056 #if HAVE_IPV6
3057 if (h != last && !disable_ipv6)
3058 {
3059 for (h = host; h != last; h = h->next)
3060 {
3061 host_item temp;
3062 host_item *next = h->next;
3063 if (h->mx != next->mx || /* If next is different MX */
3064 h->address == NULL || /* OR this one is unset */
3065 Ustrchr(h->address, ':') != NULL || /* OR this one is IPv6 */
3066 (next->address != NULL &&
3067 Ustrchr(next->address, ':') == NULL)) /* OR next is IPv4 */
3068 continue; /* move on to next */
3069 temp = *h; /* otherwise, swap */
3070 temp.next = next->next;
3071 *h = *next;
3072 h->next = next;
3073 *next = temp;
3074 }
3075 }
3076 #endif
3077
3078 /* Remove any duplicate IP addresses and then scan the list of hosts for any
3079 whose IP addresses are on the local host. If any are found, all hosts with the
3080 same or higher MX values are removed. However, if the local host has the lowest
3081 numbered MX, then HOST_FOUND_LOCAL is returned. Otherwise, if at least one host
3082 with an IP address is on the list, HOST_FOUND is returned. Otherwise,
3083 HOST_FIND_FAILED is returned, but in this case do not update the yield, as it
3084 might have been set to HOST_FIND_AGAIN just above here. If not, it will already
3085 be HOST_FIND_FAILED. */
3086
3087 host_remove_duplicates(host, &last);
3088 rc = host_scan_for_local_hosts(host, &last, removed);
3089 if (rc != HOST_FIND_FAILED) yield = rc;
3090
3091 DEBUG(D_host_lookup)
3092 {
3093 if (fully_qualified_name != NULL)
3094 debug_printf("fully qualified name = %s\n", *fully_qualified_name);
3095 debug_printf("host_find_bydns yield = %s (%d); returned hosts:\n",
3096 (yield == HOST_FOUND)? "HOST_FOUND" :
3097 (yield == HOST_FOUND_LOCAL)? "HOST_FOUND_LOCAL" :
3098 (yield == HOST_FIND_AGAIN)? "HOST_FIND_AGAIN" :
3099 (yield == HOST_FIND_FAILED)? "HOST_FIND_FAILED" : "?",
3100 yield);
3101 for (h = host; h != last->next; h = h->next)
3102 {
3103 debug_printf(" %s %s MX=%d %s", h->name,
3104 !h->address ? US"<null>" : h->address, h->mx,
3105 h->dnssec == DS_YES ? US"DNSSEC " : US"");
3106 if (h->port != PORT_NONE) debug_printf("port=%d ", h->port);
3107 if (h->status >= hstatus_unusable) debug_printf("*");
3108 debug_printf("\n");
3109 }
3110 }
3111
3112 out:
3113
3114 dns_init(FALSE, FALSE, FALSE); /* clear the dnssec bit for getaddrbyname */
3115 return yield;
3116 }
3117
3118 /*************************************************
3119 **************************************************
3120 * Stand-alone test program *
3121 **************************************************
3122 *************************************************/
3123
3124 #ifdef STAND_ALONE
3125
3126 int main(int argc, char **cargv)
3127 {
3128 host_item h;
3129 int whichrrs = HOST_FIND_BY_MX | HOST_FIND_BY_A;
3130 BOOL byname = FALSE;
3131 BOOL qualify_single = TRUE;
3132 BOOL search_parents = FALSE;
3133 BOOL request_dnssec = FALSE;
3134 BOOL require_dnssec = FALSE;
3135 uschar **argv = USS cargv;
3136 uschar buffer[256];
3137
3138 disable_ipv6 = FALSE;
3139 primary_hostname = US"";
3140 store_pool = POOL_MAIN;
3141 debug_selector = D_host_lookup|D_interface;
3142 debug_file = stdout;
3143 debug_fd = fileno(debug_file);
3144
3145 printf("Exim stand-alone host functions test\n");
3146
3147 host_find_interfaces();
3148 debug_selector = D_host_lookup | D_dns;
3149
3150 if (argc > 1) primary_hostname = argv[1];
3151
3152 /* So that debug level changes can be done first */
3153
3154 dns_init(qualify_single, search_parents, FALSE);
3155
3156 printf("Testing host lookup\n");
3157 printf("> ");
3158 while (Ufgets(buffer, 256, stdin) != NULL)
3159 {
3160 int rc;
3161 int len = Ustrlen(buffer);
3162 uschar *fully_qualified_name;
3163
3164 while (len > 0 && isspace(buffer[len-1])) len--;
3165 buffer[len] = 0;
3166
3167 if (Ustrcmp(buffer, "q") == 0) break;
3168
3169 if (Ustrcmp(buffer, "byname") == 0) byname = TRUE;
3170 else if (Ustrcmp(buffer, "no_byname") == 0) byname = FALSE;
3171 else if (Ustrcmp(buffer, "a_only") == 0) whichrrs = HOST_FIND_BY_A;
3172 else if (Ustrcmp(buffer, "mx_only") == 0) whichrrs = HOST_FIND_BY_MX;
3173 else if (Ustrcmp(buffer, "srv_only") == 0) whichrrs = HOST_FIND_BY_SRV;
3174 else if (Ustrcmp(buffer, "srv+a") == 0)
3175 whichrrs = HOST_FIND_BY_SRV | HOST_FIND_BY_A;
3176 else if (Ustrcmp(buffer, "srv+mx") == 0)
3177 whichrrs = HOST_FIND_BY_SRV | HOST_FIND_BY_MX;
3178 else if (Ustrcmp(buffer, "srv+mx+a") == 0)
3179 whichrrs = HOST_FIND_BY_SRV | HOST_FIND_BY_MX | HOST_FIND_BY_A;
3180 else if (Ustrcmp(buffer, "qualify_single") == 0) qualify_single = TRUE;
3181 else if (Ustrcmp(buffer, "no_qualify_single") == 0) qualify_single = FALSE;
3182 else if (Ustrcmp(buffer, "search_parents") == 0) search_parents = TRUE;
3183 else if (Ustrcmp(buffer, "no_search_parents") == 0) search_parents = FALSE;
3184 else if (Ustrcmp(buffer, "request_dnssec") == 0) request_dnssec = TRUE;
3185 else if (Ustrcmp(buffer, "no_request_dnssec") == 0) request_dnssec = FALSE;
3186 else if (Ustrcmp(buffer, "require_dnssec") == 0) require_dnssec = TRUE;
3187 else if (Ustrcmp(buffer, "no_reqiret_dnssec") == 0) require_dnssec = FALSE;
3188 else if (Ustrcmp(buffer, "test_harness") == 0)
3189 running_in_test_harness = !running_in_test_harness;
3190 else if (Ustrcmp(buffer, "ipv6") == 0) disable_ipv6 = !disable_ipv6;
3191 else if (Ustrcmp(buffer, "res_debug") == 0)
3192 {
3193 _res.options ^= RES_DEBUG;
3194 }
3195 else if (Ustrncmp(buffer, "retrans", 7) == 0)
3196 {
3197 (void)sscanf(CS(buffer+8), "%d", &dns_retrans);
3198 _res.retrans = dns_retrans;
3199 }
3200 else if (Ustrncmp(buffer, "retry", 5) == 0)
3201 {
3202 (void)sscanf(CS(buffer+6), "%d", &dns_retry);
3203 _res.retry = dns_retry;
3204 }
3205 else
3206 {
3207 int flags = whichrrs;
3208 dnssec d;
3209
3210 h.name = buffer;
3211 h.next = NULL;
3212 h.mx = MX_NONE;
3213 h.port = PORT_NONE;
3214 h.status = hstatus_unknown;
3215 h.why = hwhy_unknown;
3216 h.address = NULL;
3217
3218 if (qualify_single) flags |= HOST_FIND_QUALIFY_SINGLE;
3219 if (search_parents) flags |= HOST_FIND_SEARCH_PARENTS;
3220
3221 d.request = request_dnssec ? &h.name : NULL;
3222 d.require = require_dnssec ? &h.name : NULL;
3223
3224 rc = byname
3225 ? host_find_byname(&h, NULL, flags, &fully_qualified_name, TRUE)
3226 : host_find_bydns(&h, NULL, flags, US"smtp", NULL, NULL,
3227 &d, &fully_qualified_name, NULL);
3228
3229 if (rc == HOST_FIND_FAILED) printf("Failed\n");
3230 else if (rc == HOST_FIND_AGAIN) printf("Again\n");
3231 else if (rc == HOST_FOUND_LOCAL) printf("Local\n");
3232 }
3233
3234 printf("\n> ");
3235 }
3236
3237 printf("Testing host_aton\n");
3238 printf("> ");
3239 while (Ufgets(buffer, 256, stdin) != NULL)
3240 {
3241 int i;
3242 int x[4];
3243 int len = Ustrlen(buffer);
3244
3245 while (len > 0 && isspace(buffer[len-1])) len--;
3246 buffer[len] = 0;
3247
3248 if (Ustrcmp(buffer, "q") == 0) break;
3249
3250 len = host_aton(buffer, x);
3251 printf("length = %d ", len);
3252 for (i = 0; i < len; i++)
3253 {
3254 printf("%04x ", (x[i] >> 16) & 0xffff);
3255 printf("%04x ", x[i] & 0xffff);
3256 }
3257 printf("\n> ");
3258 }
3259
3260 printf("\n");
3261
3262 printf("Testing host_name_lookup\n");
3263 printf("> ");
3264 while (Ufgets(buffer, 256, stdin) != NULL)
3265 {
3266 int len = Ustrlen(buffer);
3267 while (len > 0 && isspace(buffer[len-1])) len--;
3268 buffer[len] = 0;
3269 if (Ustrcmp(buffer, "q") == 0) break;
3270 sender_host_address = buffer;
3271 sender_host_name = NULL;
3272 sender_host_aliases = NULL;
3273 host_lookup_msg = US"";
3274 host_lookup_failed = FALSE;
3275 if (host_name_lookup() == FAIL) /* Debug causes printing */
3276 printf("Lookup failed:%s\n", host_lookup_msg);
3277 printf("\n> ");
3278 }
3279
3280 printf("\n");
3281
3282 return 0;
3283 }
3284 #endif /* STAND_ALONE */
3285
3286 /* vi: aw ai sw=2
3287 */
3288 /* End of host.c */