0da99334a8dc8195d764af901b40df62a7c550f8
[exim.git] / src / src / host.c
1 /*************************************************
2 * Exim - an Internet mail transport agent *
3 *************************************************/
4
5 /* Copyright (c) University of Cambridge 1995 - 2018 */
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 (f.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. However, STARTTLS has to be forgotten and redone
524 on a multi-message conn, so this will be called once per message then. Hence
525 we use malloc, so we can free.
526
527 Arguments: none
528 Returns: nothing
529 */
530
531 void
532 host_build_sender_fullhost(void)
533 {
534 BOOL show_helo = TRUE;
535 uschar * address, * fullhost, * rcvhost, * reset_point;
536 int len;
537
538 if (!sender_host_address) return;
539
540 reset_point = store_get(0);
541
542 /* Set up address, with or without the port. After discussion, it seems that
543 the only format that doesn't cause trouble is [aaaa]:pppp. However, we can't
544 use this directly as the first item for Received: because it ain't an RFC 2822
545 domain. Sigh. */
546
547 address = string_sprintf("[%s]:%d", sender_host_address, sender_host_port);
548 if (!LOGGING(incoming_port) || sender_host_port <= 0)
549 *(Ustrrchr(address, ':')) = 0;
550
551 /* If there's no EHLO/HELO data, we can't show it. */
552
553 if (!sender_helo_name) show_helo = FALSE;
554
555 /* If HELO/EHLO was followed by an IP literal, it's messy because of two
556 features of IPv6. Firstly, there's the "IPv6:" prefix (Exim is liberal and
557 doesn't require this, for historical reasons). Secondly, IPv6 addresses may not
558 be given in canonical form, so we have to canonicalize them before comparing. As
559 it happens, the code works for both IPv4 and IPv6. */
560
561 else if (sender_helo_name[0] == '[' &&
562 sender_helo_name[(len=Ustrlen(sender_helo_name))-1] == ']')
563 {
564 int offset = 1;
565 uschar *helo_ip;
566
567 if (strncmpic(sender_helo_name + 1, US"IPv6:", 5) == 0) offset += 5;
568 if (strncmpic(sender_helo_name + 1, US"IPv4:", 5) == 0) offset += 5;
569
570 helo_ip = string_copyn(sender_helo_name + offset, len - offset - 1);
571
572 if (string_is_ip_address(helo_ip, NULL) != 0)
573 {
574 int x[4], y[4];
575 int sizex, sizey;
576 uschar ipx[48], ipy[48]; /* large enough for full IPv6 */
577
578 sizex = host_aton(helo_ip, x);
579 sizey = host_aton(sender_host_address, y);
580
581 (void)host_nmtoa(sizex, x, -1, ipx, ':');
582 (void)host_nmtoa(sizey, y, -1, ipy, ':');
583
584 if (strcmpic(ipx, ipy) == 0) show_helo = FALSE;
585 }
586 }
587
588 /* Host name is not verified */
589
590 if (!sender_host_name)
591 {
592 uschar *portptr = Ustrstr(address, "]:");
593 gstring * g;
594 int adlen; /* Sun compiler doesn't like ++ in initializers */
595
596 adlen = portptr ? (++portptr - address) : Ustrlen(address);
597 fullhost = sender_helo_name
598 ? string_sprintf("(%s) %s", sender_helo_name, address)
599 : address;
600
601 g = string_catn(NULL, address, adlen);
602
603 if (sender_ident || show_helo || portptr)
604 {
605 int firstptr;
606 g = string_catn(g, US" (", 2);
607 firstptr = g->ptr;
608
609 if (portptr)
610 g = string_append(g, 2, US"port=", portptr + 1);
611
612 if (show_helo)
613 g = string_append(g, 2,
614 firstptr == g->ptr ? US"helo=" : US" helo=", sender_helo_name);
615
616 if (sender_ident)
617 g = string_append(g, 2,
618 firstptr == g->ptr ? US"ident=" : US" ident=", sender_ident);
619
620 g = string_catn(g, US")", 1);
621 }
622
623 rcvhost = string_from_gstring(g);
624 }
625
626 /* Host name is known and verified. Unless we've already found that the HELO
627 data matches the IP address, compare it with the name. */
628
629 else
630 {
631 if (show_helo && strcmpic(sender_host_name, sender_helo_name) == 0)
632 show_helo = FALSE;
633
634 if (show_helo)
635 {
636 fullhost = string_sprintf("%s (%s) %s", sender_host_name,
637 sender_helo_name, address);
638 rcvhost = sender_ident
639 ? string_sprintf("%s\n\t(%s helo=%s ident=%s)", sender_host_name,
640 address, sender_helo_name, sender_ident)
641 : string_sprintf("%s (%s helo=%s)", sender_host_name,
642 address, sender_helo_name);
643 }
644 else
645 {
646 fullhost = string_sprintf("%s %s", sender_host_name, address);
647 rcvhost = sender_ident
648 ? string_sprintf("%s (%s ident=%s)", sender_host_name, address,
649 sender_ident)
650 : string_sprintf("%s (%s)", sender_host_name, address);
651 }
652 }
653
654 if (sender_fullhost) store_free(sender_fullhost);
655 sender_fullhost = string_copy_malloc(fullhost);
656 if (sender_rcvhost) store_free(sender_rcvhost);
657 sender_rcvhost = string_copy_malloc(rcvhost);
658
659 store_reset(reset_point);
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 (LOGGING(incoming_interface) && interface_address != NULL)
699 iface = string_sprintf(" I=[%s]:%d", interface_address, interface_port);
700 if (sender_ident == NULL)
701 (void)string_format(big_buffer, big_buffer_size, "%s%s%s",
702 flag, sender_fullhost, iface);
703 else
704 (void)string_format(big_buffer, big_buffer_size, "%s%s%s U=%s",
705 flag, sender_fullhost, iface, sender_ident);
706 }
707 return big_buffer;
708 }
709
710 #endif /* STAND_ALONE */
711
712
713
714
715 /*************************************************
716 * Build list of local interfaces *
717 *************************************************/
718
719 /* This function interprets the contents of the local_interfaces or
720 extra_local_interfaces options, and creates an ip_address_item block for each
721 item on the list. There is no special interpretation of any IP addresses; in
722 particular, 0.0.0.0 and ::0 are returned without modification. If any address
723 includes a port, it is set in the block. Otherwise the port value is set to
724 zero.
725
726 Arguments:
727 list the list
728 name the name of the option being expanded
729
730 Returns: a chain of ip_address_items, each containing to a textual
731 version of an IP address, and a port number (host order) or
732 zero if no port was given with the address
733 */
734
735 ip_address_item *
736 host_build_ifacelist(const uschar *list, uschar *name)
737 {
738 int sep = 0;
739 uschar *s;
740 ip_address_item * yield = NULL, * last = NULL, * next;
741
742 while ((s = string_nextinlist(&list, &sep, NULL, 0)))
743 {
744 int ipv;
745 int port = host_address_extract_port(s); /* Leaves just the IP address */
746
747 if (!(ipv = string_is_ip_address(s, NULL)))
748 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Malformed IP address \"%s\" in %s",
749 s, name);
750
751 /* Skip IPv6 addresses if IPv6 is disabled. */
752
753 if (disable_ipv6 && ipv == 6) continue;
754
755 /* This use of strcpy() is OK because we have checked that s is a valid IP
756 address above. The field in the ip_address_item is large enough to hold an
757 IPv6 address. */
758
759 next = store_get(sizeof(ip_address_item));
760 next->next = NULL;
761 Ustrcpy(next->address, s);
762 next->port = port;
763 next->v6_include_v4 = FALSE;
764
765 if (!yield)
766 yield = last = next;
767 else
768 {
769 last->next = next;
770 last = next;
771 }
772 }
773
774 return yield;
775 }
776
777
778
779
780
781 /*************************************************
782 * Find addresses on local interfaces *
783 *************************************************/
784
785 /* This function finds the addresses of local IP interfaces. These are used
786 when testing for routing to the local host. As the function may be called more
787 than once, the list is preserved in permanent store, pointed to by a static
788 variable, to save doing the work more than once per process.
789
790 The generic list of interfaces is obtained by calling host_build_ifacelist()
791 for local_interfaces and extra_local_interfaces. This list scanned to remove
792 duplicates (which may exist with different ports - not relevant here). If
793 either of the wildcard IP addresses (0.0.0.0 and ::0) are encountered, they are
794 replaced by the appropriate (IPv4 or IPv6) list of actual local interfaces,
795 obtained from os_find_running_interfaces().
796
797 Arguments: none
798 Returns: a chain of ip_address_items, each containing to a textual
799 version of an IP address; the port numbers are not relevant
800 */
801
802
803 /* First, a local subfunction to add an interface to a list in permanent store,
804 but only if there isn't a previous copy of that address on the list. */
805
806 static ip_address_item *
807 add_unique_interface(ip_address_item *list, ip_address_item *ipa)
808 {
809 ip_address_item *ipa2;
810 for (ipa2 = list; ipa2 != NULL; ipa2 = ipa2->next)
811 if (Ustrcmp(ipa2->address, ipa->address) == 0) return list;
812 ipa2 = store_get_perm(sizeof(ip_address_item));
813 *ipa2 = *ipa;
814 ipa2->next = list;
815 return ipa2;
816 }
817
818
819 /* This is the globally visible function */
820
821 ip_address_item *
822 host_find_interfaces(void)
823 {
824 ip_address_item *running_interfaces = NULL;
825
826 if (local_interface_data == NULL)
827 {
828 void *reset_item = store_get(0);
829 ip_address_item *dlist = host_build_ifacelist(CUS local_interfaces,
830 US"local_interfaces");
831 ip_address_item *xlist = host_build_ifacelist(CUS extra_local_interfaces,
832 US"extra_local_interfaces");
833 ip_address_item *ipa;
834
835 if (dlist == NULL) dlist = xlist; else
836 {
837 for (ipa = dlist; ipa->next != NULL; ipa = ipa->next);
838 ipa->next = xlist;
839 }
840
841 for (ipa = dlist; ipa != NULL; ipa = ipa->next)
842 {
843 if (Ustrcmp(ipa->address, "0.0.0.0") == 0 ||
844 Ustrcmp(ipa->address, "::0") == 0)
845 {
846 ip_address_item *ipa2;
847 BOOL ipv6 = ipa->address[0] == ':';
848 if (running_interfaces == NULL)
849 running_interfaces = os_find_running_interfaces();
850 for (ipa2 = running_interfaces; ipa2 != NULL; ipa2 = ipa2->next)
851 {
852 if ((Ustrchr(ipa2->address, ':') != NULL) == ipv6)
853 local_interface_data = add_unique_interface(local_interface_data,
854 ipa2);
855 }
856 }
857 else
858 {
859 local_interface_data = add_unique_interface(local_interface_data, ipa);
860 DEBUG(D_interface)
861 {
862 debug_printf("Configured local interface: address=%s", ipa->address);
863 if (ipa->port != 0) debug_printf(" port=%d", ipa->port);
864 debug_printf("\n");
865 }
866 }
867 }
868 store_reset(reset_item);
869 }
870
871 return local_interface_data;
872 }
873
874
875
876
877
878 /*************************************************
879 * Convert network IP address to text *
880 *************************************************/
881
882 /* Given an IPv4 or IPv6 address in binary, convert it to a text
883 string and return the result in a piece of new store. The address can
884 either be given directly, or passed over in a sockaddr structure. Note
885 that this isn't the converse of host_aton() because of byte ordering
886 differences. See host_nmtoa() below.
887
888 Arguments:
889 type if < 0 then arg points to a sockaddr, else
890 either AF_INET or AF_INET6
891 arg points to a sockaddr if type is < 0, or
892 points to an IPv4 address (32 bits), or
893 points to an IPv6 address (128 bits),
894 in both cases, in network byte order
895 buffer if NULL, the result is returned in gotten store;
896 else points to a buffer to hold the answer
897 portptr points to where to put the port number, if non NULL; only
898 used when type < 0
899
900 Returns: pointer to character string
901 */
902
903 uschar *
904 host_ntoa(int type, const void *arg, uschar *buffer, int *portptr)
905 {
906 uschar *yield;
907
908 /* The new world. It is annoying that we have to fish out the address from
909 different places in the block, depending on what kind of address it is. It
910 is also a pain that inet_ntop() returns a const uschar *, whereas the IPv4
911 function inet_ntoa() returns just uschar *, and some picky compilers insist
912 on warning if one assigns a const uschar * to a uschar *. Hence the casts. */
913
914 #if HAVE_IPV6
915 uschar addr_buffer[46];
916 if (type < 0)
917 {
918 int family = ((struct sockaddr *)arg)->sa_family;
919 if (family == AF_INET6)
920 {
921 struct sockaddr_in6 *sk = (struct sockaddr_in6 *)arg;
922 yield = US inet_ntop(family, &(sk->sin6_addr), CS addr_buffer,
923 sizeof(addr_buffer));
924 if (portptr != NULL) *portptr = ntohs(sk->sin6_port);
925 }
926 else
927 {
928 struct sockaddr_in *sk = (struct sockaddr_in *)arg;
929 yield = US inet_ntop(family, &(sk->sin_addr), CS addr_buffer,
930 sizeof(addr_buffer));
931 if (portptr != NULL) *portptr = ntohs(sk->sin_port);
932 }
933 }
934 else
935 {
936 yield = US inet_ntop(type, arg, CS addr_buffer, sizeof(addr_buffer));
937 }
938
939 /* If the result is a mapped IPv4 address, show it in V4 format. */
940
941 if (Ustrncmp(yield, "::ffff:", 7) == 0) yield += 7;
942
943 #else /* HAVE_IPV6 */
944
945 /* The old world */
946
947 if (type < 0)
948 {
949 yield = US inet_ntoa(((struct sockaddr_in *)arg)->sin_addr);
950 if (portptr != NULL) *portptr = ntohs(((struct sockaddr_in *)arg)->sin_port);
951 }
952 else
953 yield = US inet_ntoa(*((struct in_addr *)arg));
954 #endif
955
956 /* If there is no buffer, put the string into some new store. */
957
958 if (buffer == NULL) return string_copy(yield);
959
960 /* Callers of this function with a non-NULL buffer must ensure that it is
961 large enough to hold an IPv6 address, namely, at least 46 bytes. That's what
962 makes this use of strcpy() OK. */
963
964 Ustrcpy(buffer, yield);
965 return buffer;
966 }
967
968
969
970
971 /*************************************************
972 * Convert address text to binary *
973 *************************************************/
974
975 /* Given the textual form of an IP address, convert it to binary in an
976 array of ints. IPv4 addresses occupy one int; IPv6 addresses occupy 4 ints.
977 The result has the first byte in the most significant byte of the first int. In
978 other words, the result is not in network byte order, but in host byte order.
979 As a result, this is not the converse of host_ntoa(), which expects network
980 byte order. See host_nmtoa() below.
981
982 Arguments:
983 address points to the textual address, checked for syntax
984 bin points to an array of 4 ints
985
986 Returns: the number of ints used
987 */
988
989 int
990 host_aton(const uschar *address, int *bin)
991 {
992 int x[4];
993 int v4offset = 0;
994
995 /* Handle IPv6 address, which may end with an IPv4 address. It may also end
996 with a "scope", introduced by a percent sign. This code is NOT enclosed in #if
997 HAVE_IPV6 in order that IPv6 addresses are recognized even if IPv6 is not
998 supported. */
999
1000 if (Ustrchr(address, ':') != NULL)
1001 {
1002 const uschar *p = address;
1003 const uschar *component[8];
1004 BOOL ipv4_ends = FALSE;
1005 int ci = 0;
1006 int nulloffset = 0;
1007 int v6count = 8;
1008 int i;
1009
1010 /* If the address starts with a colon, it will start with two colons.
1011 Just lose the first one, which will leave a null first component. */
1012
1013 if (*p == ':') p++;
1014
1015 /* Split the address into components separated by colons. The input address
1016 is supposed to be checked for syntax. There was a case where this was
1017 overlooked; to guard against that happening again, check here and crash if
1018 there are too many components. */
1019
1020 while (*p != 0 && *p != '%')
1021 {
1022 int len = Ustrcspn(p, ":%");
1023 if (len == 0) nulloffset = ci;
1024 if (ci > 7) log_write(0, LOG_MAIN|LOG_PANIC_DIE,
1025 "Internal error: invalid IPv6 address \"%s\" passed to host_aton()",
1026 address);
1027 component[ci++] = p;
1028 p += len;
1029 if (*p == ':') p++;
1030 }
1031
1032 /* If the final component contains a dot, it is a trailing v4 address.
1033 As the syntax is known to be checked, just set up for a trailing
1034 v4 address and restrict the v6 part to 6 components. */
1035
1036 if (Ustrchr(component[ci-1], '.') != NULL)
1037 {
1038 address = component[--ci];
1039 ipv4_ends = TRUE;
1040 v4offset = 3;
1041 v6count = 6;
1042 }
1043
1044 /* If there are fewer than 6 or 8 components, we have to insert some
1045 more empty ones in the middle. */
1046
1047 if (ci < v6count)
1048 {
1049 int insert_count = v6count - ci;
1050 for (i = v6count-1; i > nulloffset + insert_count; i--)
1051 component[i] = component[i - insert_count];
1052 while (i > nulloffset) component[i--] = US"";
1053 }
1054
1055 /* Now turn the components into binary in pairs and bung them
1056 into the vector of ints. */
1057
1058 for (i = 0; i < v6count; i += 2)
1059 bin[i/2] = (Ustrtol(component[i], NULL, 16) << 16) +
1060 Ustrtol(component[i+1], NULL, 16);
1061
1062 /* If there was no terminating v4 component, we are done. */
1063
1064 if (!ipv4_ends) return 4;
1065 }
1066
1067 /* Handle IPv4 address */
1068
1069 (void)sscanf(CS address, "%d.%d.%d.%d", x, x+1, x+2, x+3);
1070 bin[v4offset] = ((uint)x[0] << 24) + (x[1] << 16) + (x[2] << 8) + x[3];
1071 return v4offset+1;
1072 }
1073
1074
1075 /*************************************************
1076 * Apply mask to an IP address *
1077 *************************************************/
1078
1079 /* Mask an address held in 1 or 4 ints, with the ms bit in the ms bit of the
1080 first int, etc.
1081
1082 Arguments:
1083 count the number of ints
1084 binary points to the ints to be masked
1085 mask the count of ms bits to leave, or -1 if no masking
1086
1087 Returns: nothing
1088 */
1089
1090 void
1091 host_mask(int count, int *binary, int mask)
1092 {
1093 int i;
1094 if (mask < 0) mask = 99999;
1095 for (i = 0; i < count; i++)
1096 {
1097 int wordmask;
1098 if (mask == 0) wordmask = 0;
1099 else if (mask < 32)
1100 {
1101 wordmask = (uint)(-1) << (32 - mask);
1102 mask = 0;
1103 }
1104 else
1105 {
1106 wordmask = -1;
1107 mask -= 32;
1108 }
1109 binary[i] &= wordmask;
1110 }
1111 }
1112
1113
1114
1115
1116 /*************************************************
1117 * Convert masked IP address in ints to text *
1118 *************************************************/
1119
1120 /* We can't use host_ntoa() because it assumes the binary values are in network
1121 byte order, and these are the result of host_aton(), which puts them in ints in
1122 host byte order. Also, we really want IPv6 addresses to be in a canonical
1123 format, so we output them with no abbreviation. In a number of cases we can't
1124 use the normal colon separator in them because it terminates keys in lsearch
1125 files, so we want to use dot instead. There's an argument that specifies what
1126 to use for IPv6 addresses.
1127
1128 Arguments:
1129 count 1 or 4 (number of ints)
1130 binary points to the ints
1131 mask mask value; if < 0 don't add to result
1132 buffer big enough to hold the result
1133 sep component separator character for IPv6 addresses
1134
1135 Returns: the number of characters placed in buffer, not counting
1136 the final nul.
1137 */
1138
1139 int
1140 host_nmtoa(int count, int *binary, int mask, uschar *buffer, int sep)
1141 {
1142 int i, j;
1143 uschar *tt = buffer;
1144
1145 if (count == 1)
1146 {
1147 j = binary[0];
1148 for (i = 24; i >= 0; i -= 8)
1149 tt += sprintf(CS tt, "%d.", (j >> i) & 255);
1150 }
1151 else
1152 for (i = 0; i < 4; i++)
1153 {
1154 j = binary[i];
1155 tt += sprintf(CS tt, "%04x%c%04x%c", (j >> 16) & 0xffff, sep, j & 0xffff, sep);
1156 }
1157
1158 tt--; /* lose final separator */
1159
1160 if (mask < 0)
1161 *tt = 0;
1162 else
1163 tt += sprintf(CS tt, "/%d", mask);
1164
1165 return tt - buffer;
1166 }
1167
1168
1169 /* Like host_nmtoa() but: ipv6-only, canonical output, no mask
1170
1171 Arguments:
1172 binary points to the ints
1173 buffer big enough to hold the result
1174
1175 Returns: the number of characters placed in buffer, not counting
1176 the final nul.
1177 */
1178
1179 int
1180 ipv6_nmtoa(int * binary, uschar * buffer)
1181 {
1182 int i, j, k;
1183 uschar * c = buffer;
1184 uschar * d = NULL; /* shut insufficiently "clever" compiler up */
1185
1186 for (i = 0; i < 4; i++)
1187 { /* expand to text */
1188 j = binary[i];
1189 c += sprintf(CS c, "%x:%x:", (j >> 16) & 0xffff, j & 0xffff);
1190 }
1191
1192 for (c = buffer, k = -1, i = 0; i < 8; i++)
1193 { /* find longest 0-group sequence */
1194 if (*c == '0') /* must be "0:" */
1195 {
1196 uschar * s = c;
1197 j = i;
1198 while (c[2] == '0') i++, c += 2;
1199 if (i-j > k)
1200 {
1201 k = i-j; /* length of sequence */
1202 d = s; /* start of sequence */
1203 }
1204 }
1205 while (*++c != ':') ;
1206 c++;
1207 }
1208
1209 c[-1] = '\0'; /* drop trailing colon */
1210
1211 /* debug_printf("%s: D k %d <%s> <%s>\n", __FUNCTION__, k, d, d + 2*(k+1)); */
1212 if (k >= 0)
1213 { /* collapse */
1214 c = d + 2*(k+1);
1215 if (d == buffer) c--; /* need extra colon */
1216 *d++ = ':'; /* 1st 0 */
1217 while ((*d++ = *c++)) ;
1218 }
1219 else
1220 d = c;
1221
1222 return d - buffer;
1223 }
1224
1225
1226
1227 /*************************************************
1228 * Check port for tls_on_connect *
1229 *************************************************/
1230
1231 /* This function checks whether a given incoming port is configured for tls-
1232 on-connect. It is called from the daemon and from inetd handling. If the global
1233 option tls_on_connect is already set, all ports operate this way. Otherwise, we
1234 check the tls_on_connect_ports option for a list of ports.
1235
1236 Argument: a port number
1237 Returns: TRUE or FALSE
1238 */
1239
1240 BOOL
1241 host_is_tls_on_connect_port(int port)
1242 {
1243 int sep = 0;
1244 uschar buffer[32];
1245 const uschar *list = tls_in.on_connect_ports;
1246 uschar *s;
1247 uschar *end;
1248
1249 if (tls_in.on_connect) return TRUE;
1250
1251 while ((s = string_nextinlist(&list, &sep, buffer, sizeof(buffer))))
1252 if (Ustrtol(s, &end, 10) == port)
1253 return TRUE;
1254
1255 return FALSE;
1256 }
1257
1258
1259
1260 /*************************************************
1261 * Check whether host is in a network *
1262 *************************************************/
1263
1264 /* This function checks whether a given IP address matches a pattern that
1265 represents either a single host, or a network (using CIDR notation). The caller
1266 of this function must check the syntax of the arguments before calling it.
1267
1268 Arguments:
1269 host string representation of the ip-address to check
1270 net string representation of the network, with optional CIDR mask
1271 maskoffset offset to the / that introduces the mask in the key
1272 zero if there is no mask
1273
1274 Returns:
1275 TRUE the host is inside the network
1276 FALSE the host is NOT inside the network
1277 */
1278
1279 BOOL
1280 host_is_in_net(const uschar *host, const uschar *net, int maskoffset)
1281 {
1282 int i;
1283 int address[4];
1284 int incoming[4];
1285 int mlen;
1286 int size = host_aton(net, address);
1287 int insize;
1288
1289 /* No mask => all bits to be checked */
1290
1291 if (maskoffset == 0) mlen = 99999; /* Big number */
1292 else mlen = Uatoi(net + maskoffset + 1);
1293
1294 /* Convert the incoming address to binary. */
1295
1296 insize = host_aton(host, incoming);
1297
1298 /* Convert IPv4 addresses given in IPv6 compatible mode, which represent
1299 connections from IPv4 hosts to IPv6 hosts, that is, addresses of the form
1300 ::ffff:<v4address>, to IPv4 format. */
1301
1302 if (insize == 4 && incoming[0] == 0 && incoming[1] == 0 &&
1303 incoming[2] == 0xffff)
1304 {
1305 insize = 1;
1306 incoming[0] = incoming[3];
1307 }
1308
1309 /* No match if the sizes don't agree. */
1310
1311 if (insize != size) return FALSE;
1312
1313 /* Else do the masked comparison. */
1314
1315 for (i = 0; i < size; i++)
1316 {
1317 int mask;
1318 if (mlen == 0) mask = 0;
1319 else if (mlen < 32)
1320 {
1321 mask = (uint)(-1) << (32 - mlen);
1322 mlen = 0;
1323 }
1324 else
1325 {
1326 mask = -1;
1327 mlen -= 32;
1328 }
1329 if ((incoming[i] & mask) != (address[i] & mask)) return FALSE;
1330 }
1331
1332 return TRUE;
1333 }
1334
1335
1336
1337 /*************************************************
1338 * Scan host list for local hosts *
1339 *************************************************/
1340
1341 /* Scan through a chain of addresses and check whether any of them is the
1342 address of an interface on the local machine. If so, remove that address and
1343 any previous ones with the same MX value, and all subsequent ones (which will
1344 have greater or equal MX values) from the chain. Note: marking them as unusable
1345 is NOT the right thing to do because it causes the hosts not to be used for
1346 other domains, for which they may well be correct.
1347
1348 The hosts may be part of a longer chain; we only process those between the
1349 initial pointer and the "last" pointer.
1350
1351 There is also a list of "pseudo-local" host names which are checked against the
1352 host names. Any match causes that host item to be treated the same as one which
1353 matches a local IP address.
1354
1355 If the very first host is a local host, then all MX records had a precedence
1356 greater than or equal to that of the local host. Either there's a problem in
1357 the DNS, or an apparently remote name turned out to be an abbreviation for the
1358 local host. Give a specific return code, and let the caller decide what to do.
1359 Otherwise, give a success code if at least one host address has been found.
1360
1361 Arguments:
1362 host pointer to the first host in the chain
1363 lastptr pointer to pointer to the last host in the chain (may be updated)
1364 removed if not NULL, set TRUE if some local addresses were removed
1365 from the list
1366
1367 Returns:
1368 HOST_FOUND if there is at least one host with an IP address on the chain
1369 and an MX value less than any MX value associated with the
1370 local host
1371 HOST_FOUND_LOCAL if a local host is among the lowest-numbered MX hosts; when
1372 the host addresses were obtained from A records or
1373 gethostbyname(), the MX values are set to -1.
1374 HOST_FIND_FAILED if no valid hosts with set IP addresses were found
1375 */
1376
1377 int
1378 host_scan_for_local_hosts(host_item *host, host_item **lastptr, BOOL *removed)
1379 {
1380 int yield = HOST_FIND_FAILED;
1381 host_item *last = *lastptr;
1382 host_item *prev = NULL;
1383 host_item *h;
1384
1385 if (removed != NULL) *removed = FALSE;
1386
1387 if (local_interface_data == NULL) local_interface_data = host_find_interfaces();
1388
1389 for (h = host; h != last->next; h = h->next)
1390 {
1391 #ifndef STAND_ALONE
1392 if (hosts_treat_as_local != NULL)
1393 {
1394 int rc;
1395 const uschar *save = deliver_domain;
1396 deliver_domain = h->name; /* set $domain */
1397 rc = match_isinlist(string_copylc(h->name), CUSS &hosts_treat_as_local, 0,
1398 &domainlist_anchor, NULL, MCL_DOMAIN, TRUE, NULL);
1399 deliver_domain = save;
1400 if (rc == OK) goto FOUND_LOCAL;
1401 }
1402 #endif
1403
1404 /* It seems that on many operating systems, 0.0.0.0 is treated as a synonym
1405 for 127.0.0.1 and refers to the local host. We therefore force it always to
1406 be treated as local. */
1407
1408 if (h->address != NULL)
1409 {
1410 ip_address_item *ip;
1411 if (Ustrcmp(h->address, "0.0.0.0") == 0) goto FOUND_LOCAL;
1412 for (ip = local_interface_data; ip != NULL; ip = ip->next)
1413 if (Ustrcmp(h->address, ip->address) == 0) goto FOUND_LOCAL;
1414 yield = HOST_FOUND; /* At least one remote address has been found */
1415 }
1416
1417 /* Update prev to point to the last host item before any that have
1418 the same MX value as the one we have just considered. */
1419
1420 if (h->next == NULL || h->next->mx != h->mx) prev = h;
1421 }
1422
1423 return yield; /* No local hosts found: return HOST_FOUND or HOST_FIND_FAILED */
1424
1425 /* A host whose IP address matches a local IP address, or whose name matches
1426 something in hosts_treat_as_local has been found. */
1427
1428 FOUND_LOCAL:
1429
1430 if (prev == NULL)
1431 {
1432 HDEBUG(D_host_lookup) debug_printf((h->mx >= 0)?
1433 "local host has lowest MX\n" :
1434 "local host found for non-MX address\n");
1435 return HOST_FOUND_LOCAL;
1436 }
1437
1438 HDEBUG(D_host_lookup)
1439 {
1440 debug_printf("local host in host list - removed hosts:\n");
1441 for (h = prev->next; h != last->next; h = h->next)
1442 debug_printf(" %s %s %d\n", h->name, h->address, h->mx);
1443 }
1444
1445 if (removed != NULL) *removed = TRUE;
1446 prev->next = last->next;
1447 *lastptr = prev;
1448 return yield;
1449 }
1450
1451
1452
1453
1454 /*************************************************
1455 * Remove duplicate IPs in host list *
1456 *************************************************/
1457
1458 /* You would think that administrators could set up their DNS records so that
1459 one ended up with a list of unique IP addresses after looking up A or MX
1460 records, but apparently duplication is common. So we scan such lists and
1461 remove the later duplicates. Note that we may get lists in which some host
1462 addresses are not set.
1463
1464 Arguments:
1465 host pointer to the first host in the chain
1466 lastptr pointer to pointer to the last host in the chain (may be updated)
1467
1468 Returns: nothing
1469 */
1470
1471 static void
1472 host_remove_duplicates(host_item *host, host_item **lastptr)
1473 {
1474 while (host != *lastptr)
1475 {
1476 if (host->address != NULL)
1477 {
1478 host_item *h = host;
1479 while (h != *lastptr)
1480 {
1481 if (h->next->address != NULL &&
1482 Ustrcmp(h->next->address, host->address) == 0)
1483 {
1484 DEBUG(D_host_lookup) debug_printf("duplicate IP address %s (MX=%d) "
1485 "removed\n", host->address, h->next->mx);
1486 if (h->next == *lastptr) *lastptr = h;
1487 h->next = h->next->next;
1488 }
1489 else h = h->next;
1490 }
1491 }
1492 /* If the last item was removed, host may have become == *lastptr */
1493 if (host != *lastptr) host = host->next;
1494 }
1495 }
1496
1497
1498
1499
1500 /*************************************************
1501 * Find sender host name by gethostbyaddr() *
1502 *************************************************/
1503
1504 /* This used to be the only way it was done, but it turns out that not all
1505 systems give aliases for calls to gethostbyaddr() - or one of the modern
1506 equivalents like getipnodebyaddr(). Fortunately, multiple PTR records are rare,
1507 but they can still exist. This function is now used only when a DNS lookup of
1508 the IP address fails, in order to give access to /etc/hosts.
1509
1510 Arguments: none
1511 Returns: OK, DEFER, FAIL
1512 */
1513
1514 static int
1515 host_name_lookup_byaddr(void)
1516 {
1517 int len;
1518 uschar *s, *t;
1519 struct hostent *hosts;
1520 struct in_addr addr;
1521 unsigned long time_msec = 0; /* init to quieten dumb static analysis */
1522
1523 if (slow_lookup_log) time_msec = get_time_in_ms();
1524
1525 /* Lookup on IPv6 system */
1526
1527 #if HAVE_IPV6
1528 if (Ustrchr(sender_host_address, ':') != NULL)
1529 {
1530 struct in6_addr addr6;
1531 if (inet_pton(AF_INET6, CS sender_host_address, &addr6) != 1)
1532 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "unable to parse \"%s\" as an "
1533 "IPv6 address", sender_host_address);
1534 #if HAVE_GETIPNODEBYADDR
1535 hosts = getipnodebyaddr(CS &addr6, sizeof(addr6), AF_INET6, &h_errno);
1536 #else
1537 hosts = gethostbyaddr(CS &addr6, sizeof(addr6), AF_INET6);
1538 #endif
1539 }
1540 else
1541 {
1542 if (inet_pton(AF_INET, CS sender_host_address, &addr) != 1)
1543 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "unable to parse \"%s\" as an "
1544 "IPv4 address", sender_host_address);
1545 #if HAVE_GETIPNODEBYADDR
1546 hosts = getipnodebyaddr(CS &addr, sizeof(addr), AF_INET, &h_errno);
1547 #else
1548 hosts = gethostbyaddr(CS &addr, sizeof(addr), AF_INET);
1549 #endif
1550 }
1551
1552 /* Do lookup on IPv4 system */
1553
1554 #else
1555 addr.s_addr = (S_ADDR_TYPE)inet_addr(CS sender_host_address);
1556 hosts = gethostbyaddr(CS(&addr), sizeof(addr), AF_INET);
1557 #endif
1558
1559 if ( slow_lookup_log
1560 && (time_msec = get_time_in_ms() - time_msec) > slow_lookup_log
1561 )
1562 log_long_lookup(US"name", sender_host_address, time_msec);
1563
1564 /* Failed to look up the host. */
1565
1566 if (hosts == NULL)
1567 {
1568 HDEBUG(D_host_lookup) debug_printf("IP address lookup failed: h_errno=%d\n",
1569 h_errno);
1570 return (h_errno == TRY_AGAIN || h_errno == NO_RECOVERY) ? DEFER : FAIL;
1571 }
1572
1573 /* It seems there are some records in the DNS that yield an empty name. We
1574 treat this as non-existent. In some operating systems, this is returned as an
1575 empty string; in others as a single dot. */
1576
1577 if (hosts->h_name == NULL || hosts->h_name[0] == 0 || hosts->h_name[0] == '.')
1578 {
1579 HDEBUG(D_host_lookup) debug_printf("IP address lookup yielded an empty name: "
1580 "treated as non-existent host name\n");
1581 return FAIL;
1582 }
1583
1584 /* Copy and lowercase the name, which is in static storage in many systems.
1585 Put it in permanent memory. */
1586
1587 s = US hosts->h_name;
1588 len = Ustrlen(s) + 1;
1589 t = sender_host_name = store_get_perm(len);
1590 while (*s != 0) *t++ = tolower(*s++);
1591 *t = 0;
1592
1593 /* If the host has aliases, build a copy of the alias list */
1594
1595 if (hosts->h_aliases != NULL)
1596 {
1597 int count = 1;
1598 uschar **aliases, **ptr;
1599 for (aliases = USS hosts->h_aliases; *aliases != NULL; aliases++) count++;
1600 ptr = sender_host_aliases = store_get_perm(count * sizeof(uschar *));
1601 for (aliases = USS hosts->h_aliases; *aliases != NULL; aliases++)
1602 {
1603 uschar *s = *aliases;
1604 int len = Ustrlen(s) + 1;
1605 uschar *t = *ptr++ = store_get_perm(len);
1606 while (*s != 0) *t++ = tolower(*s++);
1607 *t = 0;
1608 }
1609 *ptr = NULL;
1610 }
1611
1612 return OK;
1613 }
1614
1615
1616
1617 /*************************************************
1618 * Find host name for incoming call *
1619 *************************************************/
1620
1621 /* Put the name in permanent store, pointed to by sender_host_name. We also set
1622 up a list of alias names, pointed to by sender_host_alias. The list is
1623 NULL-terminated. The incoming address is in sender_host_address, either in
1624 dotted-quad form for IPv4 or in colon-separated form for IPv6.
1625
1626 This function does a thorough check that the names it finds point back to the
1627 incoming IP address. Any that do not are discarded. Note that this is relied on
1628 by the ACL reverse_host_lookup check.
1629
1630 On some systems, get{host,ipnode}byaddr() appears to do this internally, but
1631 this it not universally true. Also, for release 4.30, this function was changed
1632 to do a direct DNS lookup first, by default[1], because it turns out that that
1633 is the only guaranteed way to find all the aliases on some systems. My
1634 experiments indicate that Solaris gethostbyaddr() gives the aliases for but
1635 Linux does not.
1636
1637 [1] The actual order is controlled by the host_lookup_order option.
1638
1639 Arguments: none
1640 Returns: OK on success, the answer being placed in the global variable
1641 sender_host_name, with any aliases in a list hung off
1642 sender_host_aliases
1643 FAIL if no host name can be found
1644 DEFER if a temporary error was encountered
1645
1646 The variable host_lookup_msg is set to an empty string on success, or to a
1647 reason for the failure otherwise, in a form suitable for tagging onto an error
1648 message, and also host_lookup_failed is set TRUE if the lookup failed. If there
1649 was a defer, host_lookup_deferred is set TRUE.
1650
1651 Any dynamically constructed string for host_lookup_msg must be in permanent
1652 store, because it might be used for several incoming messages on the same SMTP
1653 connection. */
1654
1655 int
1656 host_name_lookup(void)
1657 {
1658 int old_pool, rc;
1659 int sep = 0;
1660 uschar *hname, *save_hostname;
1661 uschar **aliases;
1662 uschar buffer[256];
1663 uschar *ordername;
1664 const uschar *list = host_lookup_order;
1665 dns_record *rr;
1666 dns_answer dnsa;
1667 dns_scan dnss;
1668
1669 sender_host_dnssec = host_lookup_deferred = host_lookup_failed = FALSE;
1670
1671 HDEBUG(D_host_lookup)
1672 debug_printf("looking up host name for %s\n", sender_host_address);
1673
1674 /* For testing the case when a lookup does not complete, we have a special
1675 reserved IP address. */
1676
1677 if (f.running_in_test_harness &&
1678 Ustrcmp(sender_host_address, "99.99.99.99") == 0)
1679 {
1680 HDEBUG(D_host_lookup)
1681 debug_printf("Test harness: host name lookup returns DEFER\n");
1682 host_lookup_deferred = TRUE;
1683 return DEFER;
1684 }
1685
1686 /* Do lookups directly in the DNS or via gethostbyaddr() (or equivalent), in
1687 the order specified by the host_lookup_order option. */
1688
1689 while ((ordername = string_nextinlist(&list, &sep, buffer, sizeof(buffer))))
1690 {
1691 if (strcmpic(ordername, US"bydns") == 0)
1692 {
1693 dns_init(FALSE, FALSE, FALSE); /* dnssec ctrl by dns_dnssec_ok glbl */
1694 dns_build_reverse(sender_host_address, buffer);
1695 rc = dns_lookup_timerwrap(&dnsa, buffer, T_PTR, NULL);
1696
1697 /* The first record we come across is used for the name; others are
1698 considered to be aliases. We have to scan twice, in order to find out the
1699 number of aliases. However, if all the names are empty, we will behave as
1700 if failure. (PTR records that yield empty names have been encountered in
1701 the DNS.) */
1702
1703 if (rc == DNS_SUCCEED)
1704 {
1705 uschar **aptr = NULL;
1706 int ssize = 264;
1707 int count = 0;
1708 int old_pool = store_pool;
1709
1710 sender_host_dnssec = dns_is_secure(&dnsa);
1711 DEBUG(D_dns)
1712 debug_printf("Reverse DNS security status: %s\n",
1713 sender_host_dnssec ? "DNSSEC verified (AD)" : "unverified");
1714
1715 store_pool = POOL_PERM; /* Save names in permanent storage */
1716
1717 for (rr = dns_next_rr(&dnsa, &dnss, RESET_ANSWERS);
1718 rr;
1719 rr = dns_next_rr(&dnsa, &dnss, RESET_NEXT))
1720 if (rr->type == T_PTR)
1721 count++;
1722
1723 /* Get store for the list of aliases. For compatibility with
1724 gethostbyaddr, we make an empty list if there are none. */
1725
1726 aptr = sender_host_aliases = store_get(count * sizeof(uschar *));
1727
1728 /* Re-scan and extract the names */
1729
1730 for (rr = dns_next_rr(&dnsa, &dnss, RESET_ANSWERS);
1731 rr;
1732 rr = dns_next_rr(&dnsa, &dnss, RESET_NEXT))
1733 {
1734 uschar *s = NULL;
1735 if (rr->type != T_PTR) continue;
1736 s = store_get(ssize);
1737
1738 /* If an overlong response was received, the data will have been
1739 truncated and dn_expand may fail. */
1740
1741 if (dn_expand(dnsa.answer, dnsa.answer + dnsa.answerlen,
1742 US (rr->data), (DN_EXPAND_ARG4_TYPE)(s), ssize) < 0)
1743 {
1744 log_write(0, LOG_MAIN, "host name alias list truncated for %s",
1745 sender_host_address);
1746 break;
1747 }
1748
1749 store_reset(s + Ustrlen(s) + 1);
1750 if (s[0] == 0)
1751 {
1752 HDEBUG(D_host_lookup) debug_printf("IP address lookup yielded an "
1753 "empty name: treated as non-existent host name\n");
1754 continue;
1755 }
1756 if (!sender_host_name) sender_host_name = s;
1757 else *aptr++ = s;
1758 while (*s != 0) { *s = tolower(*s); s++; }
1759 }
1760
1761 *aptr = NULL; /* End of alias list */
1762 store_pool = old_pool; /* Reset store pool */
1763
1764 /* If we've found a names, break out of the "order" loop */
1765
1766 if (sender_host_name != NULL) break;
1767 }
1768
1769 /* If the DNS lookup deferred, we must also defer. */
1770
1771 if (rc == DNS_AGAIN)
1772 {
1773 HDEBUG(D_host_lookup)
1774 debug_printf("IP address PTR lookup gave temporary error\n");
1775 host_lookup_deferred = TRUE;
1776 return DEFER;
1777 }
1778 }
1779
1780 /* Do a lookup using gethostbyaddr() - or equivalent */
1781
1782 else if (strcmpic(ordername, US"byaddr") == 0)
1783 {
1784 HDEBUG(D_host_lookup)
1785 debug_printf("IP address lookup using gethostbyaddr()\n");
1786 rc = host_name_lookup_byaddr();
1787 if (rc == DEFER)
1788 {
1789 host_lookup_deferred = TRUE;
1790 return rc; /* Can't carry on */
1791 }
1792 if (rc == OK) break; /* Found a name */
1793 }
1794 } /* Loop for bydns/byaddr scanning */
1795
1796 /* If we have failed to find a name, return FAIL and log when required.
1797 NB host_lookup_msg must be in permanent store. */
1798
1799 if (sender_host_name == NULL)
1800 {
1801 if (host_checking || !f.log_testing_mode)
1802 log_write(L_host_lookup_failed, LOG_MAIN, "no host name found for IP "
1803 "address %s", sender_host_address);
1804 host_lookup_msg = US" (failed to find host name from IP address)";
1805 host_lookup_failed = TRUE;
1806 return FAIL;
1807 }
1808
1809 HDEBUG(D_host_lookup)
1810 {
1811 uschar **aliases = sender_host_aliases;
1812 debug_printf("IP address lookup yielded \"%s\"\n", sender_host_name);
1813 while (*aliases != NULL) debug_printf(" alias \"%s\"\n", *aliases++);
1814 }
1815
1816 /* We need to verify that a forward lookup on the name we found does indeed
1817 correspond to the address. This is for security: in principle a malefactor who
1818 happened to own a reverse zone could set it to point to any names at all.
1819
1820 This code was present in versions of Exim before 3.20. At that point I took it
1821 out because I thought that gethostbyaddr() did the check anyway. It turns out
1822 that this isn't always the case, so it's coming back in at 4.01. This version
1823 is actually better, because it also checks aliases.
1824
1825 The code was made more robust at release 4.21. Prior to that, it accepted all
1826 the names if any of them had the correct IP address. Now the code checks all
1827 the names, and accepts only those that have the correct IP address. */
1828
1829 save_hostname = sender_host_name; /* Save for error messages */
1830 aliases = sender_host_aliases;
1831 for (hname = sender_host_name; hname; hname = *aliases++)
1832 {
1833 int rc;
1834 BOOL ok = FALSE;
1835 host_item h;
1836 dnssec_domains d;
1837
1838 h.next = NULL;
1839 h.name = hname;
1840 h.mx = MX_NONE;
1841 h.address = NULL;
1842 d.request = sender_host_dnssec ? US"*" : NULL;;
1843 d.require = NULL;
1844
1845 if ( (rc = host_find_bydns(&h, NULL, HOST_FIND_BY_A | HOST_FIND_BY_AAAA,
1846 NULL, NULL, NULL, &d, NULL, NULL)) == HOST_FOUND
1847 || rc == HOST_FOUND_LOCAL
1848 )
1849 {
1850 host_item *hh;
1851 HDEBUG(D_host_lookup) debug_printf("checking addresses for %s\n", hname);
1852
1853 /* If the forward lookup was not secure we cancel the is-secure variable */
1854
1855 DEBUG(D_dns) debug_printf("Forward DNS security status: %s\n",
1856 h.dnssec == DS_YES ? "DNSSEC verified (AD)" : "unverified");
1857 if (h.dnssec != DS_YES) sender_host_dnssec = FALSE;
1858
1859 for (hh = &h; hh; hh = hh->next)
1860 if (host_is_in_net(hh->address, sender_host_address, 0))
1861 {
1862 HDEBUG(D_host_lookup) debug_printf(" %s OK\n", hh->address);
1863 ok = TRUE;
1864 break;
1865 }
1866 else
1867 HDEBUG(D_host_lookup) debug_printf(" %s\n", hh->address);
1868
1869 if (!ok) HDEBUG(D_host_lookup)
1870 debug_printf("no IP address for %s matched %s\n", hname,
1871 sender_host_address);
1872 }
1873 else if (rc == HOST_FIND_AGAIN)
1874 {
1875 HDEBUG(D_host_lookup) debug_printf("temporary error for host name lookup\n");
1876 host_lookup_deferred = TRUE;
1877 sender_host_name = NULL;
1878 return DEFER;
1879 }
1880 else
1881 HDEBUG(D_host_lookup) debug_printf("no IP addresses found for %s\n", hname);
1882
1883 /* If this name is no good, and it's the sender name, set it null pro tem;
1884 if it's an alias, just remove it from the list. */
1885
1886 if (!ok)
1887 {
1888 if (hname == sender_host_name) sender_host_name = NULL; else
1889 {
1890 uschar **a; /* Don't amalgamate - some */
1891 a = --aliases; /* compilers grumble */
1892 while (*a != NULL) { *a = a[1]; a++; }
1893 }
1894 }
1895 }
1896
1897 /* If sender_host_name == NULL, it means we didn't like the name. Replace
1898 it with the first alias, if there is one. */
1899
1900 if (sender_host_name == NULL && *sender_host_aliases != NULL)
1901 sender_host_name = *sender_host_aliases++;
1902
1903 /* If we now have a main name, all is well. */
1904
1905 if (sender_host_name != NULL) return OK;
1906
1907 /* We have failed to find an address that matches. */
1908
1909 HDEBUG(D_host_lookup)
1910 debug_printf("%s does not match any IP address for %s\n",
1911 sender_host_address, save_hostname);
1912
1913 /* This message must be in permanent store */
1914
1915 old_pool = store_pool;
1916 store_pool = POOL_PERM;
1917 host_lookup_msg = string_sprintf(" (%s does not match any IP address for %s)",
1918 sender_host_address, save_hostname);
1919 store_pool = old_pool;
1920 host_lookup_failed = TRUE;
1921 return FAIL;
1922 }
1923
1924
1925
1926
1927 /*************************************************
1928 * Find IP address(es) for host by name *
1929 *************************************************/
1930
1931 /* The input is a host_item structure with the name filled in and the address
1932 field set to NULL. We use gethostbyname() or getipnodebyname() or
1933 gethostbyname2(), as appropriate. Of course, these functions may use the DNS,
1934 but they do not do MX processing. It appears, however, that in some systems the
1935 current setting of resolver options is used when one of these functions calls
1936 the resolver. For this reason, we call dns_init() at the start, with arguments
1937 influenced by bits in "flags", just as we do for host_find_bydns().
1938
1939 The second argument provides a host list (usually an IP list) of hosts to
1940 ignore. This makes it possible to ignore IPv6 link-local addresses or loopback
1941 addresses in unreasonable places.
1942
1943 The lookup may result in a change of name. For compatibility with the dns
1944 lookup, return this via fully_qualified_name as well as updating the host item.
1945 The lookup may also yield more than one IP address, in which case chain on
1946 subsequent host_item structures.
1947
1948 Arguments:
1949 host a host item with the name and MX filled in;
1950 the address is to be filled in;
1951 multiple IP addresses cause other host items to be
1952 chained on.
1953 ignore_target_hosts a list of hosts to ignore
1954 flags HOST_FIND_QUALIFY_SINGLE ) passed to
1955 HOST_FIND_SEARCH_PARENTS ) dns_init()
1956 fully_qualified_name if not NULL, set to point to host name for
1957 compatibility with host_find_bydns
1958 local_host_check TRUE if a check for the local host is wanted
1959
1960 Returns: HOST_FIND_FAILED Failed to find the host or domain
1961 HOST_FIND_AGAIN Try again later
1962 HOST_FOUND Host found - data filled in
1963 HOST_FOUND_LOCAL Host found and is the local host
1964 */
1965
1966 int
1967 host_find_byname(host_item *host, const uschar *ignore_target_hosts, int flags,
1968 const uschar **fully_qualified_name, BOOL local_host_check)
1969 {
1970 int i, yield, times;
1971 uschar **addrlist;
1972 host_item *last = NULL;
1973 BOOL temp_error = FALSE;
1974 #if HAVE_IPV6
1975 int af;
1976 #endif
1977
1978 /* Make sure DNS options are set as required. This appears to be necessary in
1979 some circumstances when the get..byname() function actually calls the DNS. */
1980
1981 dns_init((flags & HOST_FIND_QUALIFY_SINGLE) != 0,
1982 (flags & HOST_FIND_SEARCH_PARENTS) != 0,
1983 FALSE); /* Cannot retrieve dnssec status so do not request */
1984
1985 /* In an IPv6 world, unless IPv6 has been disabled, we need to scan for both
1986 kinds of address, so go round the loop twice. Note that we have ensured that
1987 AF_INET6 is defined even in an IPv4 world, which makes for slightly tidier
1988 code. However, if dns_ipv4_lookup matches the domain, we also just do IPv4
1989 lookups here (except when testing standalone). */
1990
1991 #if HAVE_IPV6
1992 #ifdef STAND_ALONE
1993 if (disable_ipv6)
1994 #else
1995 if (disable_ipv6 ||
1996 (dns_ipv4_lookup != NULL &&
1997 match_isinlist(host->name, CUSS &dns_ipv4_lookup, 0, NULL, NULL,
1998 MCL_DOMAIN, TRUE, NULL) == OK))
1999 #endif
2000
2001 { af = AF_INET; times = 1; }
2002 else
2003 { af = AF_INET6; times = 2; }
2004
2005 /* No IPv6 support */
2006
2007 #else /* HAVE_IPV6 */
2008 times = 1;
2009 #endif /* HAVE_IPV6 */
2010
2011 /* Initialize the flag that gets set for DNS syntax check errors, so that the
2012 interface to this function can be similar to host_find_bydns. */
2013
2014 f.host_find_failed_syntax = FALSE;
2015
2016 /* Loop to look up both kinds of address in an IPv6 world */
2017
2018 for (i = 1; i <= times;
2019 #if HAVE_IPV6
2020 af = AF_INET, /* If 2 passes, IPv4 on the second */
2021 #endif
2022 i++)
2023 {
2024 BOOL ipv4_addr;
2025 int error_num = 0;
2026 struct hostent *hostdata;
2027 unsigned long time_msec = 0; /* compiler quietening */
2028
2029 #ifdef STAND_ALONE
2030 printf("Looking up: %s\n", host->name);
2031 #endif
2032
2033 if (slow_lookup_log) time_msec = get_time_in_ms();
2034
2035 #if HAVE_IPV6
2036 if (f.running_in_test_harness)
2037 hostdata = host_fake_gethostbyname(host->name, af, &error_num);
2038 else
2039 {
2040 #if HAVE_GETIPNODEBYNAME
2041 hostdata = getipnodebyname(CS host->name, af, 0, &error_num);
2042 #else
2043 hostdata = gethostbyname2(CS host->name, af);
2044 error_num = h_errno;
2045 #endif
2046 }
2047
2048 #else /* not HAVE_IPV6 */
2049 if (f.running_in_test_harness)
2050 hostdata = host_fake_gethostbyname(host->name, AF_INET, &error_num);
2051 else
2052 {
2053 hostdata = gethostbyname(CS host->name);
2054 error_num = h_errno;
2055 }
2056 #endif /* HAVE_IPV6 */
2057
2058 if ( slow_lookup_log
2059 && (time_msec = get_time_in_ms() - time_msec) > slow_lookup_log)
2060 log_long_lookup(US"name", host->name, time_msec);
2061
2062 if (hostdata == NULL)
2063 {
2064 uschar *error;
2065 switch (error_num)
2066 {
2067 case HOST_NOT_FOUND: error = US"HOST_NOT_FOUND"; break;
2068 case TRY_AGAIN: error = US"TRY_AGAIN"; break;
2069 case NO_RECOVERY: error = US"NO_RECOVERY"; break;
2070 case NO_DATA: error = US"NO_DATA"; break;
2071 #if NO_DATA != NO_ADDRESS
2072 case NO_ADDRESS: error = US"NO_ADDRESS"; break;
2073 #endif
2074 default: error = US"?"; break;
2075 }
2076
2077 DEBUG(D_host_lookup) debug_printf("%s returned %d (%s)\n",
2078 #if HAVE_IPV6
2079 #if HAVE_GETIPNODEBYNAME
2080 (af == AF_INET6)? "getipnodebyname(af=inet6)" : "getipnodebyname(af=inet)",
2081 #else
2082 (af == AF_INET6)? "gethostbyname2(af=inet6)" : "gethostbyname2(af=inet)",
2083 #endif
2084 #else
2085 "gethostbyname",
2086 #endif
2087 error_num, error);
2088
2089 if (error_num == TRY_AGAIN || error_num == NO_RECOVERY) temp_error = TRUE;
2090 continue;
2091 }
2092 if ((hostdata->h_addr_list)[0] == NULL) continue;
2093
2094 /* Replace the name with the fully qualified one if necessary, and fill in
2095 the fully_qualified_name pointer. */
2096
2097 if (hostdata->h_name[0] != 0 &&
2098 Ustrcmp(host->name, hostdata->h_name) != 0)
2099 host->name = string_copy_dnsdomain(US hostdata->h_name);
2100 if (fully_qualified_name != NULL) *fully_qualified_name = host->name;
2101
2102 /* Get the list of addresses. IPv4 and IPv6 addresses can be distinguished
2103 by their different lengths. Scan the list, ignoring any that are to be
2104 ignored, and build a chain from the rest. */
2105
2106 ipv4_addr = hostdata->h_length == sizeof(struct in_addr);
2107
2108 for (addrlist = USS hostdata->h_addr_list; *addrlist != NULL; addrlist++)
2109 {
2110 uschar *text_address =
2111 host_ntoa(ipv4_addr? AF_INET:AF_INET6, *addrlist, NULL, NULL);
2112
2113 #ifndef STAND_ALONE
2114 if (ignore_target_hosts != NULL &&
2115 verify_check_this_host(&ignore_target_hosts, NULL, host->name,
2116 text_address, NULL) == OK)
2117 {
2118 DEBUG(D_host_lookup)
2119 debug_printf("ignored host %s [%s]\n", host->name, text_address);
2120 continue;
2121 }
2122 #endif
2123
2124 /* If this is the first address, last == NULL and we put the data in the
2125 original block. */
2126
2127 if (last == NULL)
2128 {
2129 host->address = text_address;
2130 host->port = PORT_NONE;
2131 host->status = hstatus_unknown;
2132 host->why = hwhy_unknown;
2133 host->dnssec = DS_UNK;
2134 last = host;
2135 }
2136
2137 /* Else add further host item blocks for any other addresses, keeping
2138 the order. */
2139
2140 else
2141 {
2142 host_item *next = store_get(sizeof(host_item));
2143 next->name = host->name;
2144 next->mx = host->mx;
2145 next->address = text_address;
2146 next->port = PORT_NONE;
2147 next->status = hstatus_unknown;
2148 next->why = hwhy_unknown;
2149 next->dnssec = DS_UNK;
2150 next->last_try = 0;
2151 next->next = last->next;
2152 last->next = next;
2153 last = next;
2154 }
2155 }
2156 }
2157
2158 /* If no hosts were found, the address field in the original host block will be
2159 NULL. If temp_error is set, at least one of the lookups gave a temporary error,
2160 so we pass that back. */
2161
2162 if (host->address == NULL)
2163 {
2164 uschar *msg =
2165 #ifndef STAND_ALONE
2166 (message_id[0] == 0 && smtp_in != NULL)?
2167 string_sprintf("no IP address found for host %s (during %s)", host->name,
2168 smtp_get_connection_info()) :
2169 #endif
2170 string_sprintf("no IP address found for host %s", host->name);
2171
2172 HDEBUG(D_host_lookup) debug_printf("%s\n", msg);
2173 if (temp_error) goto RETURN_AGAIN;
2174 if (host_checking || !f.log_testing_mode)
2175 log_write(L_host_lookup_failed, LOG_MAIN, "%s", msg);
2176 return HOST_FIND_FAILED;
2177 }
2178
2179 /* Remove any duplicate IP addresses, then check to see if this is the local
2180 host if required. */
2181
2182 host_remove_duplicates(host, &last);
2183 yield = local_host_check?
2184 host_scan_for_local_hosts(host, &last, NULL) : HOST_FOUND;
2185
2186 HDEBUG(D_host_lookup)
2187 {
2188 const host_item *h;
2189 if (fully_qualified_name != NULL)
2190 debug_printf("fully qualified name = %s\n", *fully_qualified_name);
2191 debug_printf("%s looked up these IP addresses:\n",
2192 #if HAVE_IPV6
2193 #if HAVE_GETIPNODEBYNAME
2194 "getipnodebyname"
2195 #else
2196 "gethostbyname2"
2197 #endif
2198 #else
2199 "gethostbyname"
2200 #endif
2201 );
2202 for (h = host; h != last->next; h = h->next)
2203 debug_printf(" name=%s address=%s\n", h->name,
2204 (h->address == NULL)? US"<null>" : h->address);
2205 }
2206
2207 /* Return the found status. */
2208
2209 return yield;
2210
2211 /* Handle the case when there is a temporary error. If the name matches
2212 dns_again_means_nonexist, return permanent rather than temporary failure. */
2213
2214 RETURN_AGAIN:
2215 {
2216 #ifndef STAND_ALONE
2217 int rc;
2218 const uschar *save = deliver_domain;
2219 deliver_domain = host->name; /* set $domain */
2220 rc = match_isinlist(host->name, CUSS &dns_again_means_nonexist, 0, NULL, NULL,
2221 MCL_DOMAIN, TRUE, NULL);
2222 deliver_domain = save;
2223 if (rc == OK)
2224 {
2225 DEBUG(D_host_lookup) debug_printf("%s is in dns_again_means_nonexist: "
2226 "returning HOST_FIND_FAILED\n", host->name);
2227 return HOST_FIND_FAILED;
2228 }
2229 #endif
2230 return HOST_FIND_AGAIN;
2231 }
2232 }
2233
2234
2235
2236 /*************************************************
2237 * Fill in a host address from the DNS *
2238 *************************************************/
2239
2240 /* Given a host item, with its name, port and mx fields set, and its address
2241 field set to NULL, fill in its IP address from the DNS. If it is multi-homed,
2242 create additional host items for the additional addresses, copying all the
2243 other fields, and randomizing the order.
2244
2245 On IPv6 systems, AAAA records are sought first, then A records.
2246
2247 The host name may be changed if the DNS returns a different name - e.g. fully
2248 qualified or changed via CNAME. If fully_qualified_name is not NULL, dns_lookup
2249 ensures that it points to the fully qualified name. However, this is the fully
2250 qualified version of the original name; if a CNAME is involved, the actual
2251 canonical host name may be different again, and so we get it directly from the
2252 relevant RR. Note that we do NOT change the mx field of the host item in this
2253 function as it may be called to set the addresses of hosts taken from MX
2254 records.
2255
2256 Arguments:
2257 host points to the host item we're filling in
2258 lastptr points to pointer to last host item in a chain of
2259 host items (may be updated if host is last and gets
2260 extended because multihomed)
2261 ignore_target_hosts list of hosts to ignore
2262 allow_ip if TRUE, recognize an IP address and return it
2263 fully_qualified_name if not NULL, return fully qualified name here if
2264 the contents are different (i.e. it must be preset
2265 to something)
2266 dnssec_request if TRUE request the AD bit
2267 dnssec_require if TRUE require the AD bit
2268 whichrrs select ipv4, ipv6 results
2269
2270 Returns: HOST_FIND_FAILED couldn't find A record
2271 HOST_FIND_AGAIN try again later
2272 HOST_FIND_SECURITY dnssec required but not acheived
2273 HOST_FOUND found AAAA and/or A record(s)
2274 HOST_IGNORED found, but all IPs ignored
2275 */
2276
2277 static int
2278 set_address_from_dns(host_item *host, host_item **lastptr,
2279 const uschar *ignore_target_hosts, BOOL allow_ip,
2280 const uschar **fully_qualified_name,
2281 BOOL dnssec_request, BOOL dnssec_require, int whichrrs)
2282 {
2283 dns_record *rr;
2284 host_item *thishostlast = NULL; /* Indicates not yet filled in anything */
2285 BOOL v6_find_again = FALSE;
2286 BOOL dnssec_fail = FALSE;
2287 int i;
2288
2289 /* If allow_ip is set, a name which is an IP address returns that value
2290 as its address. This is used for MX records when allow_mx_to_ip is set, for
2291 those sites that feel they have to flaunt the RFC rules. */
2292
2293 if (allow_ip && string_is_ip_address(host->name, NULL) != 0)
2294 {
2295 #ifndef STAND_ALONE
2296 if ( ignore_target_hosts
2297 && verify_check_this_host(&ignore_target_hosts, NULL, host->name,
2298 host->name, NULL) == OK)
2299 return HOST_IGNORED;
2300 #endif
2301
2302 host->address = host->name;
2303 return HOST_FOUND;
2304 }
2305
2306 /* On an IPv6 system, unless IPv6 is disabled, go round the loop up to twice,
2307 looking for AAAA records the first time. However, unless doing standalone
2308 testing, we force an IPv4 lookup if the domain matches dns_ipv4_lookup global.
2309 On an IPv4 system, go round the loop once only, looking only for A records. */
2310
2311 #if HAVE_IPV6
2312 #ifndef STAND_ALONE
2313 if ( disable_ipv6
2314 || !(whichrrs & HOST_FIND_BY_AAAA)
2315 || (dns_ipv4_lookup
2316 && match_isinlist(host->name, CUSS &dns_ipv4_lookup, 0, NULL, NULL,
2317 MCL_DOMAIN, TRUE, NULL) == OK)
2318 )
2319 i = 0; /* look up A records only */
2320 else
2321 #endif /* STAND_ALONE */
2322
2323 i = 1; /* look up AAAA and A records */
2324
2325 /* The IPv4 world */
2326
2327 #else /* HAVE_IPV6 */
2328 i = 0; /* look up A records only */
2329 #endif /* HAVE_IPV6 */
2330
2331 for (; i >= 0; i--)
2332 {
2333 static int types[] = { T_A, T_AAAA };
2334 int type = types[i];
2335 int randoffset = i == (whichrrs & HOST_FIND_IPV4_FIRST ? 1 : 0)
2336 ? 500 : 0; /* Ensures v6/4 sort order */
2337 dns_answer dnsa;
2338 dns_scan dnss;
2339
2340 int rc = dns_lookup_timerwrap(&dnsa, host->name, type, fully_qualified_name);
2341 lookup_dnssec_authenticated = !dnssec_request ? NULL
2342 : dns_is_secure(&dnsa) ? US"yes" : US"no";
2343
2344 DEBUG(D_dns)
2345 if ( (dnssec_request || dnssec_require)
2346 && !dns_is_secure(&dnsa)
2347 && dns_is_aa(&dnsa)
2348 )
2349 debug_printf("DNS lookup of %.256s (A/AAAA) requested AD, but got AA\n", host->name);
2350
2351 /* We want to return HOST_FIND_AGAIN if one of the A or AAAA lookups
2352 fails or times out, but not if another one succeeds. (In the early
2353 IPv6 days there are name servers that always fail on AAAA, but are happy
2354 to give out an A record. We want to proceed with that A record.) */
2355
2356 if (rc != DNS_SUCCEED)
2357 {
2358 if (i == 0) /* Just tried for an A record, i.e. end of loop */
2359 {
2360 if (host->address != NULL) return HOST_FOUND; /* AAAA was found */
2361 if (rc == DNS_AGAIN || rc == DNS_FAIL || v6_find_again)
2362 return HOST_FIND_AGAIN;
2363 return HOST_FIND_FAILED; /* DNS_NOMATCH or DNS_NODATA */
2364 }
2365
2366 /* Tried for an AAAA record: remember if this was a temporary
2367 error, and look for the next record type. */
2368
2369 if (rc != DNS_NOMATCH && rc != DNS_NODATA) v6_find_again = TRUE;
2370 continue;
2371 }
2372
2373 if (dnssec_request)
2374 {
2375 if (dns_is_secure(&dnsa))
2376 {
2377 DEBUG(D_host_lookup) debug_printf("%s A DNSSEC\n", host->name);
2378 if (host->dnssec == DS_UNK) /* set in host_find_bydns() */
2379 host->dnssec = DS_YES;
2380 }
2381 else
2382 {
2383 if (dnssec_require)
2384 {
2385 dnssec_fail = TRUE;
2386 DEBUG(D_host_lookup) debug_printf("dnssec fail on %s for %.256s",
2387 i>0 ? "AAAA" : "A", host->name);
2388 continue;
2389 }
2390 if (host->dnssec == DS_YES) /* set in host_find_bydns() */
2391 {
2392 DEBUG(D_host_lookup) debug_printf("%s A cancel DNSSEC\n", host->name);
2393 host->dnssec = DS_NO;
2394 lookup_dnssec_authenticated = US"no";
2395 }
2396 }
2397 }
2398
2399 /* Lookup succeeded: fill in the given host item with the first non-ignored
2400 address found; create additional items for any others. A single A6 record
2401 may generate more than one address. The lookup had a chance to update the
2402 fqdn; we do not want any later times round the loop to do so. */
2403
2404 fully_qualified_name = NULL;
2405
2406 for (rr = dns_next_rr(&dnsa, &dnss, RESET_ANSWERS);
2407 rr;
2408 rr = dns_next_rr(&dnsa, &dnss, RESET_NEXT))
2409 {
2410 if (rr->type == type)
2411 {
2412 dns_address *da = dns_address_from_rr(&dnsa, rr);
2413
2414 DEBUG(D_host_lookup)
2415 if (!da) debug_printf("no addresses extracted from A6 RR for %s\n",
2416 host->name);
2417
2418 /* This loop runs only once for A and AAAA records, but may run
2419 several times for an A6 record that generated multiple addresses. */
2420
2421 for (; da; da = da->next)
2422 {
2423 #ifndef STAND_ALONE
2424 if (ignore_target_hosts != NULL &&
2425 verify_check_this_host(&ignore_target_hosts, NULL,
2426 host->name, da->address, NULL) == OK)
2427 {
2428 DEBUG(D_host_lookup)
2429 debug_printf("ignored host %s [%s]\n", host->name, da->address);
2430 continue;
2431 }
2432 #endif
2433
2434 /* If this is the first address, stick it in the given host block,
2435 and change the name if the returned RR has a different name. */
2436
2437 if (thishostlast == NULL)
2438 {
2439 if (strcmpic(host->name, rr->name) != 0)
2440 host->name = string_copy_dnsdomain(rr->name);
2441 host->address = da->address;
2442 host->sort_key = host->mx * 1000 + random_number(500) + randoffset;
2443 host->status = hstatus_unknown;
2444 host->why = hwhy_unknown;
2445 thishostlast = host;
2446 }
2447
2448 /* Not the first address. Check for, and ignore, duplicates. Then
2449 insert in the chain at a random point. */
2450
2451 else
2452 {
2453 int new_sort_key;
2454 host_item *next;
2455
2456 /* End of our local chain is specified by "thishostlast". */
2457
2458 for (next = host;; next = next->next)
2459 {
2460 if (Ustrcmp(CS da->address, next->address) == 0) break;
2461 if (next == thishostlast) { next = NULL; break; }
2462 }
2463 if (next != NULL) continue; /* With loop for next address */
2464
2465 /* Not a duplicate */
2466
2467 new_sort_key = host->mx * 1000 + random_number(500) + randoffset;
2468 next = store_get(sizeof(host_item));
2469
2470 /* New address goes first: insert the new block after the first one
2471 (so as not to disturb the original pointer) but put the new address
2472 in the original block. */
2473
2474 if (new_sort_key < host->sort_key)
2475 {
2476 *next = *host; /* Copies port */
2477 host->next = next;
2478 host->address = da->address;
2479 host->sort_key = new_sort_key;
2480 if (thishostlast == host) thishostlast = next; /* Local last */
2481 if (*lastptr == host) *lastptr = next; /* Global last */
2482 }
2483
2484 /* Otherwise scan down the addresses for this host to find the
2485 one to insert after. */
2486
2487 else
2488 {
2489 host_item *h = host;
2490 while (h != thishostlast)
2491 {
2492 if (new_sort_key < h->next->sort_key) break;
2493 h = h->next;
2494 }
2495 *next = *h; /* Copies port */
2496 h->next = next;
2497 next->address = da->address;
2498 next->sort_key = new_sort_key;
2499 if (h == thishostlast) thishostlast = next; /* Local last */
2500 if (h == *lastptr) *lastptr = next; /* Global last */
2501 }
2502 }
2503 }
2504 }
2505 }
2506 }
2507
2508 /* Control gets here only if the second lookup (the A record) succeeded.
2509 However, the address may not be filled in if it was ignored. */
2510
2511 return host->address
2512 ? HOST_FOUND
2513 : dnssec_fail
2514 ? HOST_FIND_SECURITY
2515 : HOST_IGNORED;
2516 }
2517
2518
2519
2520
2521 /*************************************************
2522 * Find IP addresses and host names via DNS *
2523 *************************************************/
2524
2525 /* The input is a host_item structure with the name field filled in and the
2526 address field set to NULL. This may be in a chain of other host items. The
2527 lookup may result in more than one IP address, in which case we must created
2528 new host blocks for the additional addresses, and insert them into the chain.
2529 The original name may not be fully qualified. Use the fully_qualified_name
2530 argument to return the official name, as returned by the resolver.
2531
2532 Arguments:
2533 host point to initial host item
2534 ignore_target_hosts a list of hosts to ignore
2535 whichrrs flags indicating which RRs to look for:
2536 HOST_FIND_BY_SRV => look for SRV
2537 HOST_FIND_BY_MX => look for MX
2538 HOST_FIND_BY_A => look for A
2539 HOST_FIND_BY_AAAA => look for AAAA
2540 also flags indicating how the lookup is done
2541 HOST_FIND_QUALIFY_SINGLE ) passed to the
2542 HOST_FIND_SEARCH_PARENTS ) resolver
2543 HOST_FIND_IPV4_FIRST => reverse usual result ordering
2544 HOST_FIND_IPV4_ONLY => MX results elide ipv6
2545 srv_service when SRV used, the service name
2546 srv_fail_domains DNS errors for these domains => assume nonexist
2547 mx_fail_domains DNS errors for these domains => assume nonexist
2548 dnssec_d.request => make dnssec request: domainlist
2549 dnssec_d.require => ditto and nonexist failures
2550 fully_qualified_name if not NULL, return fully-qualified name
2551 removed set TRUE if local host was removed from the list
2552
2553 Returns: HOST_FIND_FAILED Failed to find the host or domain;
2554 if there was a syntax error,
2555 host_find_failed_syntax is set.
2556 HOST_FIND_AGAIN Could not resolve at this time
2557 HOST_FIND_SECURITY dnsssec required but not acheived
2558 HOST_FOUND Host found
2559 HOST_FOUND_LOCAL The lowest MX record points to this
2560 machine, if MX records were found, or
2561 an A record that was found contains
2562 an address of the local host
2563 */
2564
2565 int
2566 host_find_bydns(host_item *host, const uschar *ignore_target_hosts, int whichrrs,
2567 uschar *srv_service, uschar *srv_fail_domains, uschar *mx_fail_domains,
2568 const dnssec_domains *dnssec_d,
2569 const uschar **fully_qualified_name, BOOL *removed)
2570 {
2571 host_item *h, *last;
2572 dns_record *rr;
2573 int rc = DNS_FAIL;
2574 int ind_type = 0;
2575 int yield;
2576 dns_answer dnsa;
2577 dns_scan dnss;
2578 BOOL dnssec_require = dnssec_d
2579 && match_isinlist(host->name, CUSS &dnssec_d->require,
2580 0, NULL, NULL, MCL_DOMAIN, TRUE, NULL) == OK;
2581 BOOL dnssec_request = dnssec_require
2582 || ( dnssec_d
2583 && match_isinlist(host->name, CUSS &dnssec_d->request,
2584 0, NULL, NULL, MCL_DOMAIN, TRUE, NULL) == OK);
2585 dnssec_status_t dnssec;
2586
2587 /* Set the default fully qualified name to the incoming name, initialize the
2588 resolver if necessary, set up the relevant options, and initialize the flag
2589 that gets set for DNS syntax check errors. */
2590
2591 if (fully_qualified_name != NULL) *fully_qualified_name = host->name;
2592 dns_init((whichrrs & HOST_FIND_QUALIFY_SINGLE) != 0,
2593 (whichrrs & HOST_FIND_SEARCH_PARENTS) != 0,
2594 dnssec_request);
2595 f.host_find_failed_syntax = FALSE;
2596
2597 /* First, if requested, look for SRV records. The service name is given; we
2598 assume TCP protocol. DNS domain names are constrained to a maximum of 256
2599 characters, so the code below should be safe. */
2600
2601 if ((whichrrs & HOST_FIND_BY_SRV) != 0)
2602 {
2603 uschar buffer[300];
2604 uschar *temp_fully_qualified_name = buffer;
2605 int prefix_length;
2606
2607 (void)sprintf(CS buffer, "_%s._tcp.%n%.256s", srv_service, &prefix_length,
2608 host->name);
2609 ind_type = T_SRV;
2610
2611 /* Search for SRV records. If the fully qualified name is different to
2612 the input name, pass back the new original domain, without the prepended
2613 magic. */
2614
2615 dnssec = DS_UNK;
2616 lookup_dnssec_authenticated = NULL;
2617 rc = dns_lookup_timerwrap(&dnsa, buffer, ind_type, CUSS &temp_fully_qualified_name);
2618
2619 DEBUG(D_dns)
2620 if ((dnssec_request || dnssec_require)
2621 && !dns_is_secure(&dnsa)
2622 && dns_is_aa(&dnsa))
2623 debug_printf("DNS lookup of %.256s (SRV) requested AD, but got AA\n", host->name);
2624
2625 if (dnssec_request)
2626 {
2627 if (dns_is_secure(&dnsa))
2628 { dnssec = DS_YES; lookup_dnssec_authenticated = US"yes"; }
2629 else
2630 { dnssec = DS_NO; lookup_dnssec_authenticated = US"no"; }
2631 }
2632
2633 if (temp_fully_qualified_name != buffer && fully_qualified_name != NULL)
2634 *fully_qualified_name = temp_fully_qualified_name + prefix_length;
2635
2636 /* On DNS failures, we give the "try again" error unless the domain is
2637 listed as one for which we continue. */
2638
2639 if (rc == DNS_SUCCEED && dnssec_require && !dns_is_secure(&dnsa))
2640 {
2641 log_write(L_host_lookup_failed, LOG_MAIN,
2642 "dnssec fail on SRV for %.256s", host->name);
2643 rc = DNS_FAIL;
2644 }
2645 if (rc == DNS_FAIL || rc == DNS_AGAIN)
2646 {
2647 #ifndef STAND_ALONE
2648 if (match_isinlist(host->name, CUSS &srv_fail_domains, 0, NULL, NULL,
2649 MCL_DOMAIN, TRUE, NULL) != OK)
2650 #endif
2651 { yield = HOST_FIND_AGAIN; goto out; }
2652 DEBUG(D_host_lookup) debug_printf("DNS_%s treated as DNS_NODATA "
2653 "(domain in srv_fail_domains)\n", (rc == DNS_FAIL)? "FAIL":"AGAIN");
2654 }
2655 }
2656
2657 /* If we did not find any SRV records, search the DNS for MX records, if
2658 requested to do so. If the result is DNS_NOMATCH, it means there is no such
2659 domain, and there's no point in going on to look for address records with the
2660 same domain. The result will be DNS_NODATA if the domain exists but has no MX
2661 records. On DNS failures, we give the "try again" error unless the domain is
2662 listed as one for which we continue. */
2663
2664 if (rc != DNS_SUCCEED && whichrrs & HOST_FIND_BY_MX)
2665 {
2666 ind_type = T_MX;
2667 dnssec = DS_UNK;
2668 lookup_dnssec_authenticated = NULL;
2669 rc = dns_lookup_timerwrap(&dnsa, host->name, ind_type, fully_qualified_name);
2670
2671 DEBUG(D_dns)
2672 if ( (dnssec_request || dnssec_require)
2673 && !dns_is_secure(&dnsa)
2674 && dns_is_aa(&dnsa))
2675 debug_printf("DNS lookup of %.256s (MX) requested AD, but got AA\n", host->name);
2676
2677 if (dnssec_request)
2678 if (dns_is_secure(&dnsa))
2679 {
2680 DEBUG(D_host_lookup) debug_printf("%s MX DNSSEC\n", host->name);
2681 dnssec = DS_YES; lookup_dnssec_authenticated = US"yes";
2682 }
2683 else
2684 {
2685 dnssec = DS_NO; lookup_dnssec_authenticated = US"no";
2686 }
2687
2688 switch (rc)
2689 {
2690 case DNS_NOMATCH:
2691 yield = HOST_FIND_FAILED; goto out;
2692
2693 case DNS_SUCCEED:
2694 if (!dnssec_require || dns_is_secure(&dnsa))
2695 break;
2696 DEBUG(D_host_lookup)
2697 debug_printf("dnssec fail on MX for %.256s", host->name);
2698 #ifndef STAND_ALONE
2699 if (match_isinlist(host->name, CUSS &mx_fail_domains, 0, NULL, NULL,
2700 MCL_DOMAIN, TRUE, NULL) != OK)
2701 { yield = HOST_FIND_SECURITY; goto out; }
2702 #endif
2703 rc = DNS_FAIL;
2704 /*FALLTHROUGH*/
2705
2706 case DNS_FAIL:
2707 case DNS_AGAIN:
2708 #ifndef STAND_ALONE
2709 if (match_isinlist(host->name, CUSS &mx_fail_domains, 0, NULL, NULL,
2710 MCL_DOMAIN, TRUE, NULL) != OK)
2711 #endif
2712 { yield = HOST_FIND_AGAIN; goto out; }
2713 DEBUG(D_host_lookup) debug_printf("DNS_%s treated as DNS_NODATA "
2714 "(domain in mx_fail_domains)\n", (rc == DNS_FAIL)? "FAIL":"AGAIN");
2715 break;
2716 }
2717 }
2718
2719 /* If we haven't found anything yet, and we are requested to do so, try for an
2720 A or AAAA record. If we find it (or them) check to see that it isn't the local
2721 host. */
2722
2723 if (rc != DNS_SUCCEED)
2724 {
2725 if (!(whichrrs & (HOST_FIND_BY_A | HOST_FIND_BY_AAAA)))
2726 {
2727 DEBUG(D_host_lookup) debug_printf("Address records are not being sought\n");
2728 yield = HOST_FIND_FAILED;
2729 goto out;
2730 }
2731
2732 last = host; /* End of local chainlet */
2733 host->mx = MX_NONE;
2734 host->port = PORT_NONE;
2735 host->dnssec = DS_UNK;
2736 lookup_dnssec_authenticated = NULL;
2737 rc = set_address_from_dns(host, &last, ignore_target_hosts, FALSE,
2738 fully_qualified_name, dnssec_request, dnssec_require, whichrrs);
2739
2740 /* If one or more address records have been found, check that none of them
2741 are local. Since we know the host items all have their IP addresses
2742 inserted, host_scan_for_local_hosts() can only return HOST_FOUND or
2743 HOST_FOUND_LOCAL. We do not need to scan for duplicate IP addresses here,
2744 because set_address_from_dns() removes them. */
2745
2746 if (rc == HOST_FOUND)
2747 rc = host_scan_for_local_hosts(host, &last, removed);
2748 else
2749 if (rc == HOST_IGNORED) rc = HOST_FIND_FAILED; /* No special action */
2750
2751 DEBUG(D_host_lookup)
2752 {
2753 host_item *h;
2754 if (host->address != NULL)
2755 {
2756 if (fully_qualified_name != NULL)
2757 debug_printf("fully qualified name = %s\n", *fully_qualified_name);
2758 for (h = host; h != last->next; h = h->next)
2759 debug_printf("%s %s mx=%d sort=%d %s\n", h->name,
2760 (h->address == NULL)? US"<null>" : h->address, h->mx, h->sort_key,
2761 (h->status >= hstatus_unusable)? US"*" : US"");
2762 }
2763 }
2764
2765 yield = rc;
2766 goto out;
2767 }
2768
2769 /* We have found one or more MX or SRV records. Sort them according to
2770 precedence. Put the data for the first one into the existing host block, and
2771 insert new host_item blocks into the chain for the remainder. For equal
2772 precedences one is supposed to randomize the order. To make this happen, the
2773 sorting is actually done on the MX value * 1000 + a random number. This is put
2774 into a host field called sort_key.
2775
2776 In the case of hosts with both IPv6 and IPv4 addresses, we want to choose the
2777 IPv6 address in preference. At this stage, we don't know what kind of address
2778 the host has. We choose a random number < 500; if later we find an A record
2779 first, we add 500 to the random number. Then for any other address records, we
2780 use random numbers in the range 0-499 for AAAA records and 500-999 for A
2781 records.
2782
2783 At this point we remove any duplicates that point to the same host, retaining
2784 only the one with the lowest precedence. We cannot yet check for precedence
2785 greater than that of the local host, because that test cannot be properly done
2786 until the addresses have been found - an MX record may point to a name for this
2787 host which is not the primary hostname. */
2788
2789 last = NULL; /* Indicates that not even the first item is filled yet */
2790
2791 for (rr = dns_next_rr(&dnsa, &dnss, RESET_ANSWERS);
2792 rr;
2793 rr = dns_next_rr(&dnsa, &dnss, RESET_NEXT)) if (rr->type == ind_type)
2794 {
2795 int precedence;
2796 int weight = 0; /* For SRV records */
2797 int port = PORT_NONE;
2798 const uschar * s = rr->data; /* MUST be unsigned for GETSHORT */
2799 uschar data[256];
2800
2801 GETSHORT(precedence, s); /* Pointer s is advanced */
2802
2803 /* For MX records, we use a random "weight" which causes multiple records of
2804 the same precedence to sort randomly. */
2805
2806 if (ind_type == T_MX)
2807 weight = random_number(500);
2808
2809 /* SRV records are specified with a port and a weight. The weight is used
2810 in a special algorithm. However, to start with, we just use it to order the
2811 records of equal priority (precedence). */
2812
2813 else
2814 {
2815 GETSHORT(weight, s);
2816 GETSHORT(port, s);
2817 }
2818
2819 /* Get the name of the host pointed to. */
2820
2821 (void)dn_expand(dnsa.answer, dnsa.answer + dnsa.answerlen, s,
2822 (DN_EXPAND_ARG4_TYPE)data, sizeof(data));
2823
2824 /* Check that we haven't already got this host on the chain; if we have,
2825 keep only the lower precedence. This situation shouldn't occur, but you
2826 never know what junk might get into the DNS (and this case has been seen on
2827 more than one occasion). */
2828
2829 if (last != NULL) /* This is not the first record */
2830 {
2831 host_item *prev = NULL;
2832
2833 for (h = host; h != last->next; prev = h, h = h->next)
2834 {
2835 if (strcmpic(h->name, data) == 0)
2836 {
2837 DEBUG(D_host_lookup)
2838 debug_printf("discarded duplicate host %s (MX=%d)\n", data,
2839 (precedence > h->mx)? precedence : h->mx);
2840 if (precedence >= h->mx) goto NEXT_MX_RR; /* Skip greater precedence */
2841 if (h == host) /* Override first item */
2842 {
2843 h->mx = precedence;
2844 host->sort_key = precedence * 1000 + weight;
2845 goto NEXT_MX_RR;
2846 }
2847
2848 /* Unwanted host item is not the first in the chain, so we can get
2849 get rid of it by cutting it out. */
2850
2851 prev->next = h->next;
2852 if (h == last) last = prev;
2853 break;
2854 }
2855 }
2856 }
2857
2858 /* If this is the first MX or SRV record, put the data into the existing host
2859 block. Otherwise, add a new block in the correct place; if it has to be
2860 before the first block, copy the first block's data to a new second block. */
2861
2862 if (!last)
2863 {
2864 host->name = string_copy_dnsdomain(data);
2865 host->address = NULL;
2866 host->port = port;
2867 host->mx = precedence;
2868 host->sort_key = precedence * 1000 + weight;
2869 host->status = hstatus_unknown;
2870 host->why = hwhy_unknown;
2871 host->dnssec = dnssec;
2872 last = host;
2873 }
2874
2875 /* Make a new host item and seek the correct insertion place */
2876
2877 else
2878 {
2879 int sort_key = precedence * 1000 + weight;
2880 host_item *next = store_get(sizeof(host_item));
2881 next->name = string_copy_dnsdomain(data);
2882 next->address = NULL;
2883 next->port = port;
2884 next->mx = precedence;
2885 next->sort_key = sort_key;
2886 next->status = hstatus_unknown;
2887 next->why = hwhy_unknown;
2888 next->dnssec = dnssec;
2889 next->last_try = 0;
2890
2891 /* Handle the case when we have to insert before the first item. */
2892
2893 if (sort_key < host->sort_key)
2894 {
2895 host_item htemp;
2896 htemp = *host;
2897 *host = *next;
2898 *next = htemp;
2899 host->next = next;
2900 if (last == host) last = next;
2901 }
2902
2903 /* Else scan down the items we have inserted as part of this exercise;
2904 don't go further. */
2905
2906 else
2907 {
2908 for (h = host; h != last; h = h->next)
2909 {
2910 if (sort_key < h->next->sort_key)
2911 {
2912 next->next = h->next;
2913 h->next = next;
2914 break;
2915 }
2916 }
2917
2918 /* Join on after the last host item that's part of this
2919 processing if we haven't stopped sooner. */
2920
2921 if (h == last)
2922 {
2923 next->next = last->next;
2924 last->next = next;
2925 last = next;
2926 }
2927 }
2928 }
2929
2930 NEXT_MX_RR: continue;
2931 }
2932
2933 if (!last) /* No rr of correct type; give up */
2934 {
2935 yield = HOST_FIND_FAILED;
2936 goto out;
2937 }
2938
2939 /* If the list of hosts was obtained from SRV records, there are two things to
2940 do. First, if there is only one host, and it's name is ".", it means there is
2941 no SMTP service at this domain. Otherwise, we have to sort the hosts of equal
2942 priority according to their weights, using an algorithm that is defined in RFC
2943 2782. The hosts are currently sorted by priority and weight. For each priority
2944 group we have to pick off one host and put it first, and then repeat for any
2945 remaining in the same priority group. */
2946
2947 if (ind_type == T_SRV)
2948 {
2949 host_item **pptr;
2950
2951 if (host == last && host->name[0] == 0)
2952 {
2953 DEBUG(D_host_lookup) debug_printf("the single SRV record is \".\"\n");
2954 yield = HOST_FIND_FAILED;
2955 goto out;
2956 }
2957
2958 DEBUG(D_host_lookup)
2959 {
2960 debug_printf("original ordering of hosts from SRV records:\n");
2961 for (h = host; h != last->next; h = h->next)
2962 debug_printf(" %s P=%d W=%d\n", h->name, h->mx, h->sort_key % 1000);
2963 }
2964
2965 for (pptr = &host, h = host; h != last; pptr = &h->next, h = h->next)
2966 {
2967 int sum = 0;
2968 host_item *hh;
2969
2970 /* Find the last following host that has the same precedence. At the same
2971 time, compute the sum of the weights and the running totals. These can be
2972 stored in the sort_key field. */
2973
2974 for (hh = h; hh != last; hh = hh->next)
2975 {
2976 int weight = hh->sort_key % 1000; /* was precedence * 1000 + weight */
2977 sum += weight;
2978 hh->sort_key = sum;
2979 if (hh->mx != hh->next->mx) break;
2980 }
2981
2982 /* If there's more than one host at this precedence (priority), we need to
2983 pick one to go first. */
2984
2985 if (hh != h)
2986 {
2987 host_item *hhh;
2988 host_item **ppptr;
2989 int randomizer = random_number(sum + 1);
2990
2991 for (ppptr = pptr, hhh = h;
2992 hhh != hh;
2993 ppptr = &(hhh->next), hhh = hhh->next)
2994 {
2995 if (hhh->sort_key >= randomizer) break;
2996 }
2997
2998 /* hhh now points to the host that should go first; ppptr points to the
2999 place that points to it. Unfortunately, if the start of the minilist is
3000 the start of the entire list, we can't just swap the items over, because
3001 we must not change the value of host, since it is passed in from outside.
3002 One day, this could perhaps be changed.
3003
3004 The special case is fudged by putting the new item *second* in the chain,
3005 and then transferring the data between the first and second items. We
3006 can't just swap the first and the chosen item, because that would mean
3007 that an item with zero weight might no longer be first. */
3008
3009 if (hhh != h)
3010 {
3011 *ppptr = hhh->next; /* Cuts it out of the chain */
3012
3013 if (h == host)
3014 {
3015 host_item temp = *h;
3016 *h = *hhh;
3017 *hhh = temp;
3018 hhh->next = temp.next;
3019 h->next = hhh;
3020 }
3021
3022 else
3023 {
3024 hhh->next = h; /* The rest of the chain follows it */
3025 *pptr = hhh; /* It takes the place of h */
3026 h = hhh; /* It's now the start of this minilist */
3027 }
3028 }
3029 }
3030
3031 /* A host has been chosen to be first at this priority and h now points
3032 to this host. There may be others at the same priority, or others at a
3033 different priority. Before we leave this host, we need to put back a sort
3034 key of the traditional MX kind, in case this host is multihomed, because
3035 the sort key is used for ordering the multiple IP addresses. We do not need
3036 to ensure that these new sort keys actually reflect the order of the hosts,
3037 however. */
3038
3039 h->sort_key = h->mx * 1000 + random_number(500);
3040 } /* Move on to the next host */
3041 }
3042
3043 /* Now we have to find IP addresses for all the hosts. We have ensured above
3044 that the names in all the host items are unique. Before release 4.61 we used to
3045 process records from the additional section in the DNS packet that returned the
3046 MX or SRV records. However, a DNS name server is free to drop any resource
3047 records from the additional section. In theory, this has always been a
3048 potential problem, but it is exacerbated by the advent of IPv6. If a host had
3049 several IPv4 addresses and some were not in the additional section, at least
3050 Exim would try the others. However, if a host had both IPv4 and IPv6 addresses
3051 and all the IPv4 (say) addresses were absent, Exim would try only for a IPv6
3052 connection, and never try an IPv4 address. When there was only IPv4
3053 connectivity, this was a disaster that did in practice occur.
3054
3055 So, from release 4.61 onwards, we always search for A and AAAA records
3056 explicitly. The names shouldn't point to CNAMES, but we use the general lookup
3057 function that handles them, just in case. If any lookup gives a soft error,
3058 change the default yield.
3059
3060 For these DNS lookups, we must disable qualify_single and search_parents;
3061 otherwise invalid host names obtained from MX or SRV records can cause trouble
3062 if they happen to match something local. */
3063
3064 yield = HOST_FIND_FAILED; /* Default yield */
3065 dns_init(FALSE, FALSE, /* Disable qualify_single and search_parents */
3066 dnssec_request || dnssec_require);
3067
3068 for (h = host; h != last->next; h = h->next)
3069 {
3070 if (h->address) continue; /* Inserted by a multihomed host */
3071
3072 rc = set_address_from_dns(h, &last, ignore_target_hosts, allow_mx_to_ip,
3073 NULL, dnssec_request, dnssec_require,
3074 whichrrs & HOST_FIND_IPV4_ONLY
3075 ? HOST_FIND_BY_A : HOST_FIND_BY_A | HOST_FIND_BY_AAAA);
3076 if (rc != HOST_FOUND)
3077 {
3078 h->status = hstatus_unusable;
3079 switch (rc)
3080 {
3081 case HOST_FIND_AGAIN: yield = rc; h->why = hwhy_deferred; break;
3082 case HOST_FIND_SECURITY: yield = rc; h->why = hwhy_insecure; break;
3083 case HOST_IGNORED: h->why = hwhy_ignored; break;
3084 default: h->why = hwhy_failed; break;
3085 }
3086 }
3087 }
3088
3089 /* Scan the list for any hosts that are marked unusable because they have
3090 been explicitly ignored, and remove them from the list, as if they did not
3091 exist. If we end up with just a single, ignored host, flatten its fields as if
3092 nothing was found. */
3093
3094 if (ignore_target_hosts)
3095 {
3096 host_item *prev = NULL;
3097 for (h = host; h != last->next; h = h->next)
3098 {
3099 REDO:
3100 if (h->why != hwhy_ignored) /* Non ignored host, just continue */
3101 prev = h;
3102 else if (prev == NULL) /* First host is ignored */
3103 {
3104 if (h != last) /* First is not last */
3105 {
3106 if (h->next == last) last = h; /* Overwrite it with next */
3107 *h = *(h->next); /* and reprocess it. */
3108 goto REDO; /* C should have redo, like Perl */
3109 }
3110 }
3111 else /* Ignored host is not first - */
3112 { /* cut it out */
3113 prev->next = h->next;
3114 if (h == last) last = prev;
3115 }
3116 }
3117
3118 if (host->why == hwhy_ignored) host->address = NULL;
3119 }
3120
3121 /* There is still one complication in the case of IPv6. Although the code above
3122 arranges that IPv6 addresses take precedence over IPv4 addresses for multihomed
3123 hosts, it doesn't do this for addresses that apply to different hosts with the
3124 same MX precedence, because the sorting on MX precedence happens first. So we
3125 have to make another pass to check for this case. We ensure that, within a
3126 single MX preference value, IPv6 addresses come first. This can separate the
3127 addresses of a multihomed host, but that should not matter. */
3128
3129 #if HAVE_IPV6
3130 if (h != last && !disable_ipv6) for (h = host; h != last; h = h->next)
3131 {
3132 host_item temp;
3133 host_item *next = h->next;
3134
3135 if ( h->mx != next->mx /* If next is different MX */
3136 || !h->address /* OR this one is unset */
3137 )
3138 continue; /* move on to next */
3139
3140 if ( whichrrs & HOST_FIND_IPV4_FIRST
3141 ? !Ustrchr(h->address, ':') /* OR this one is IPv4 */
3142 || next->address
3143 && Ustrchr(next->address, ':') /* OR next is IPv6 */
3144
3145 : Ustrchr(h->address, ':') /* OR this one is IPv6 */
3146 || next->address
3147 && !Ustrchr(next->address, ':') /* OR next is IPv4 */
3148 )
3149 continue; /* move on to next */
3150
3151 temp = *h; /* otherwise, swap */
3152 temp.next = next->next;
3153 *h = *next;
3154 h->next = next;
3155 *next = temp;
3156 }
3157 #endif
3158
3159 /* Remove any duplicate IP addresses and then scan the list of hosts for any
3160 whose IP addresses are on the local host. If any are found, all hosts with the
3161 same or higher MX values are removed. However, if the local host has the lowest
3162 numbered MX, then HOST_FOUND_LOCAL is returned. Otherwise, if at least one host
3163 with an IP address is on the list, HOST_FOUND is returned. Otherwise,
3164 HOST_FIND_FAILED is returned, but in this case do not update the yield, as it
3165 might have been set to HOST_FIND_AGAIN just above here. If not, it will already
3166 be HOST_FIND_FAILED. */
3167
3168 host_remove_duplicates(host, &last);
3169 rc = host_scan_for_local_hosts(host, &last, removed);
3170 if (rc != HOST_FIND_FAILED) yield = rc;
3171
3172 DEBUG(D_host_lookup)
3173 {
3174 if (fully_qualified_name != NULL)
3175 debug_printf("fully qualified name = %s\n", *fully_qualified_name);
3176 debug_printf("host_find_bydns yield = %s (%d); returned hosts:\n",
3177 (yield == HOST_FOUND)? "HOST_FOUND" :
3178 (yield == HOST_FOUND_LOCAL)? "HOST_FOUND_LOCAL" :
3179 (yield == HOST_FIND_SECURITY)? "HOST_FIND_SECURITY" :
3180 (yield == HOST_FIND_AGAIN)? "HOST_FIND_AGAIN" :
3181 (yield == HOST_FIND_FAILED)? "HOST_FIND_FAILED" : "?",
3182 yield);
3183 for (h = host; h != last->next; h = h->next)
3184 {
3185 debug_printf(" %s %s MX=%d %s", h->name,
3186 !h->address ? US"<null>" : h->address, h->mx,
3187 h->dnssec == DS_YES ? US"DNSSEC " : US"");
3188 if (h->port != PORT_NONE) debug_printf("port=%d ", h->port);
3189 if (h->status >= hstatus_unusable) debug_printf("*");
3190 debug_printf("\n");
3191 }
3192 }
3193
3194 out:
3195
3196 dns_init(FALSE, FALSE, FALSE); /* clear the dnssec bit for getaddrbyname */
3197 return yield;
3198 }
3199
3200 /*************************************************
3201 **************************************************
3202 * Stand-alone test program *
3203 **************************************************
3204 *************************************************/
3205
3206 #ifdef STAND_ALONE
3207
3208 int main(int argc, char **cargv)
3209 {
3210 host_item h;
3211 int whichrrs = HOST_FIND_BY_MX | HOST_FIND_BY_A | HOST_FIND_BY_AAAA;
3212 BOOL byname = FALSE;
3213 BOOL qualify_single = TRUE;
3214 BOOL search_parents = FALSE;
3215 BOOL request_dnssec = FALSE;
3216 BOOL require_dnssec = FALSE;
3217 uschar **argv = USS cargv;
3218 uschar buffer[256];
3219
3220 disable_ipv6 = FALSE;
3221 primary_hostname = US"";
3222 store_pool = POOL_MAIN;
3223 debug_selector = D_host_lookup|D_interface;
3224 debug_file = stdout;
3225 debug_fd = fileno(debug_file);
3226
3227 printf("Exim stand-alone host functions test\n");
3228
3229 host_find_interfaces();
3230 debug_selector = D_host_lookup | D_dns;
3231
3232 if (argc > 1) primary_hostname = argv[1];
3233
3234 /* So that debug level changes can be done first */
3235
3236 dns_init(qualify_single, search_parents, FALSE);
3237
3238 printf("Testing host lookup\n");
3239 printf("> ");
3240 while (Ufgets(buffer, 256, stdin) != NULL)
3241 {
3242 int rc;
3243 int len = Ustrlen(buffer);
3244 uschar *fully_qualified_name;
3245
3246 while (len > 0 && isspace(buffer[len-1])) len--;
3247 buffer[len] = 0;
3248
3249 if (Ustrcmp(buffer, "q") == 0) break;
3250
3251 if (Ustrcmp(buffer, "byname") == 0) byname = TRUE;
3252 else if (Ustrcmp(buffer, "no_byname") == 0) byname = FALSE;
3253 else if (Ustrcmp(buffer, "a_only") == 0) whichrrs = HOST_FIND_BY_A | HOST_FIND_BY_AAAA;
3254 else if (Ustrcmp(buffer, "mx_only") == 0) whichrrs = HOST_FIND_BY_MX;
3255 else if (Ustrcmp(buffer, "srv_only") == 0) whichrrs = HOST_FIND_BY_SRV;
3256 else if (Ustrcmp(buffer, "srv+a") == 0)
3257 whichrrs = HOST_FIND_BY_SRV | HOST_FIND_BY_A | HOST_FIND_BY_AAAA;
3258 else if (Ustrcmp(buffer, "srv+mx") == 0)
3259 whichrrs = HOST_FIND_BY_SRV | HOST_FIND_BY_MX;
3260 else if (Ustrcmp(buffer, "srv+mx+a") == 0)
3261 whichrrs = HOST_FIND_BY_SRV | HOST_FIND_BY_MX | HOST_FIND_BY_A | HOST_FIND_BY_AAAA;
3262 else if (Ustrcmp(buffer, "qualify_single") == 0) qualify_single = TRUE;
3263 else if (Ustrcmp(buffer, "no_qualify_single") == 0) qualify_single = FALSE;
3264 else if (Ustrcmp(buffer, "search_parents") == 0) search_parents = TRUE;
3265 else if (Ustrcmp(buffer, "no_search_parents") == 0) search_parents = FALSE;
3266 else if (Ustrcmp(buffer, "request_dnssec") == 0) request_dnssec = TRUE;
3267 else if (Ustrcmp(buffer, "no_request_dnssec") == 0) request_dnssec = FALSE;
3268 else if (Ustrcmp(buffer, "require_dnssec") == 0) require_dnssec = TRUE;
3269 else if (Ustrcmp(buffer, "no_require_dnssec") == 0) require_dnssec = FALSE;
3270 else if (Ustrcmp(buffer, "test_harness") == 0)
3271 f.running_in_test_harness = !f.running_in_test_harness;
3272 else if (Ustrcmp(buffer, "ipv6") == 0) disable_ipv6 = !disable_ipv6;
3273 else if (Ustrcmp(buffer, "res_debug") == 0)
3274 {
3275 _res.options ^= RES_DEBUG;
3276 }
3277 else if (Ustrncmp(buffer, "retrans", 7) == 0)
3278 {
3279 (void)sscanf(CS(buffer+8), "%d", &dns_retrans);
3280 _res.retrans = dns_retrans;
3281 }
3282 else if (Ustrncmp(buffer, "retry", 5) == 0)
3283 {
3284 (void)sscanf(CS(buffer+6), "%d", &dns_retry);
3285 _res.retry = dns_retry;
3286 }
3287 else
3288 {
3289 int flags = whichrrs;
3290 dnssec_domains d;
3291
3292 h.name = buffer;
3293 h.next = NULL;
3294 h.mx = MX_NONE;
3295 h.port = PORT_NONE;
3296 h.status = hstatus_unknown;
3297 h.why = hwhy_unknown;
3298 h.address = NULL;
3299
3300 if (qualify_single) flags |= HOST_FIND_QUALIFY_SINGLE;
3301 if (search_parents) flags |= HOST_FIND_SEARCH_PARENTS;
3302
3303 d.request = request_dnssec ? &h.name : NULL;
3304 d.require = require_dnssec ? &h.name : NULL;
3305
3306 rc = byname
3307 ? host_find_byname(&h, NULL, flags, &fully_qualified_name, TRUE)
3308 : host_find_bydns(&h, NULL, flags, US"smtp", NULL, NULL,
3309 &d, &fully_qualified_name, NULL);
3310
3311 switch (rc)
3312 {
3313 case HOST_FIND_FAILED: printf("Failed\n"); break;
3314 case HOST_FIND_AGAIN: printf("Again\n"); break;
3315 case HOST_FIND_SECURITY: printf("Security\n"); break;
3316 case HOST_FOUND_LOCAL: printf("Local\n"); break;
3317 }
3318 }
3319
3320 printf("\n> ");
3321 }
3322
3323 printf("Testing host_aton\n");
3324 printf("> ");
3325 while (Ufgets(buffer, 256, stdin) != NULL)
3326 {
3327 int i;
3328 int x[4];
3329 int len = Ustrlen(buffer);
3330
3331 while (len > 0 && isspace(buffer[len-1])) len--;
3332 buffer[len] = 0;
3333
3334 if (Ustrcmp(buffer, "q") == 0) break;
3335
3336 len = host_aton(buffer, x);
3337 printf("length = %d ", len);
3338 for (i = 0; i < len; i++)
3339 {
3340 printf("%04x ", (x[i] >> 16) & 0xffff);
3341 printf("%04x ", x[i] & 0xffff);
3342 }
3343 printf("\n> ");
3344 }
3345
3346 printf("\n");
3347
3348 printf("Testing host_name_lookup\n");
3349 printf("> ");
3350 while (Ufgets(buffer, 256, stdin) != NULL)
3351 {
3352 int len = Ustrlen(buffer);
3353 while (len > 0 && isspace(buffer[len-1])) len--;
3354 buffer[len] = 0;
3355 if (Ustrcmp(buffer, "q") == 0) break;
3356 sender_host_address = buffer;
3357 sender_host_name = NULL;
3358 sender_host_aliases = NULL;
3359 host_lookup_msg = US"";
3360 host_lookup_failed = FALSE;
3361 if (host_name_lookup() == FAIL) /* Debug causes printing */
3362 printf("Lookup failed:%s\n", host_lookup_msg);
3363 printf("\n> ");
3364 }
3365
3366 printf("\n");
3367
3368 return 0;
3369 }
3370 #endif /* STAND_ALONE */
3371
3372 /* vi: aw ai sw=2
3373 */
3374 /* End of host.c */