tidying
[exim.git] / src / src / host.c
CommitLineData
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1/*************************************************
2* Exim - an Internet mail transport agent *
3*************************************************/
4
f9ba5e22 5/* Copyright (c) University of Cambridge 1995 - 2018 */
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6/* See the file NOTICE for conditions of use and distribution. */
7
8/* Functions for finding hosts, either by gethostbyname(), gethostbyaddr(), or
9directly via the DNS. When IPv6 is supported, getipnodebyname() and
10getipnodebyaddr() may be used instead of gethostbyname() and gethostbyaddr(),
11if the newer functions are available. This module also contains various other
12functions concerned with hosts and addresses, and a random number function,
13used for randomizing hosts with equal MXs but available for use in other parts
14of Exim. */
15
16
17#include "exim.h"
18
19
20/* Static variable for preserving the list of interface addresses in case it is
21used more than once. */
22
23static 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
32native libraries. This causes inet_ntoa() to always yield 0.0.0.0 or
33255.255.255.255. To get round this, we provide a private version of the
34function here. It is used only if USE_INET_NTOA_FIX is set, which should happen
35only when gcc is in use on an IRIX system. Code send to me by J.T. Breitner,
36with these comments:
37
38 code by Stuart Levy
39 as seen in comp.sys.sgi.admin
40
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41August 2005: Apparently this is also needed for AIX systems; USE_INET_NTOA_FIX
42should now be set for them as well.
43
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44Arguments: sa an in_addr structure
45Returns: pointer to static text string
46*/
47
48char *
49inet_ntoa(struct in_addr sa)
50{
51static uschar addr[20];
52sprintf(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
68very good for the uses to which it is put. When running the regression tests,
69start with a fixed seed.
70
17c76198 71If you need better, see vaguely_random_number() which is potentially stronger,
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72if a crypto library is available, but might end up just calling this instead.
73
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74Arguments:
75 limit: one more than the largest number required
76
77Returns: a pseudo-random number in the range 0 to limit-1
78*/
79
80int
81random_number(int limit)
82{
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83if (limit < 1)
84 return 0;
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85if (random_seed == 0)
86 {
8768d548 87 if (f.running_in_test_harness) random_seed = 42; else
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88 {
89 int p = (int)getpid();
90 random_seed = (int)time(NULL) ^ ((p << 16) | p);
91 }
92 }
93random_seed = 1103515245 * random_seed + 12345;
94return (unsigned int)(random_seed >> 16) % limit;
95}
96
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97/*************************************************
98* Wrappers for logging lookup times *
99*************************************************/
100
101/* When the 'slow_lookup_log' variable is enabled, these wrappers will
102write to the log file all (potential) dns lookups that take more than
103slow_lookup_log milliseconds
104*/
105
106static void
107log_long_lookup(const uschar * type, const uschar * data, unsigned long msec)
108{
109log_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. */
115static unsigned long
116get_time_in_ms()
117{
118struct timeval tmp_time;
119unsigned long seconds, microseconds;
120
121gettimeofday(&tmp_time, NULL);
122seconds = (unsigned long) tmp_time.tv_sec;
123microseconds = (unsigned long) tmp_time.tv_usec;
124return seconds*1000 + microseconds/1000;
125}
126
127
128static int
129dns_lookup_timerwrap(dns_answer *dnsa, const uschar *name, int type,
130 const uschar **fully_qualified_name)
131{
132int retval;
133unsigned long time_msec;
134
135if (!slow_lookup_log)
136 return dns_lookup(dnsa, name, type, fully_qualified_name);
137
138time_msec = get_time_in_ms();
139retval = dns_lookup(dnsa, name, type, fully_qualified_name);
140if ((time_msec = get_time_in_ms() - time_msec) > slow_lookup_log)
30795c5e 141 log_long_lookup(dns_text_type(type), name, time_msec);
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142return retval;
143}
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144
145
146/*************************************************
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147* Replace gethostbyname() when testing *
148*************************************************/
149
150/* This function is called instead of gethostbyname(), gethostbyname2(), or
1fb7660f 151getipnodebyname() when running in the test harness. . It also
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152recognizes an unqualified "localhost" and forces it to the appropriate loopback
153address. IP addresses are treated as literals. For other names, it uses the DNS
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154to find the host name. In the test harness, this means it will access only the
155fake DNS resolver.
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156
157Arguments:
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
163Returns: a hostent structure or NULL for an error
164*/
165
166static struct hostent *
55414b25 167host_fake_gethostbyname(const uschar *name, int af, int *error_num)
e7726cbf 168{
70d67ad3 169#if HAVE_IPV6
e7726cbf 170int alen = (af == AF_INET)? sizeof(struct in_addr):sizeof(struct in6_addr);
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171#else
172int alen = sizeof(struct in_addr);
173#endif
174
175int ipa;
55414b25 176const uschar *lname = name;
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177uschar *adds;
178uschar **alist;
179struct hostent *yield;
8743d3ac 180dns_answer * dnsa = store_get_dns_answer();
e7726cbf 181dns_scan dnss;
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182
183DEBUG(D_host_lookup)
184 debug_printf("using host_fake_gethostbyname for %s (%s)\n", name,
accf9211 185 af == AF_INET ? "IPv4" : "IPv6");
e7726cbf 186
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187/* Handle unqualified "localhost" */
188
e7726cbf 189if (Ustrcmp(name, "localhost") == 0)
accf9211 190 lname = af == AF_INET ? US"127.0.0.1" : US"::1";
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191
192/* Handle a literal IP address */
193
d7978c0f 194if ((ipa = string_is_ip_address(lname, NULL)) != 0)
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195 if ( ipa == 4 && af == AF_INET
196 || ipa == 6 && af == AF_INET6)
e7726cbf 197 {
e7726cbf 198 int x[4];
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199 yield = store_get(sizeof(struct hostent), FALSE);
200 alist = store_get(2 * sizeof(char *), FALSE);
201 adds = store_get(alen, FALSE);
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202 yield->h_name = CS name;
203 yield->h_aliases = NULL;
204 yield->h_addrtype = af;
205 yield->h_length = alen;
206 yield->h_addr_list = CSS alist;
207 *alist++ = adds;
d7978c0f 208 for (int n = host_aton(lname, x), i = 0; i < n; i++)
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209 {
210 int y = x[i];
211 *adds++ = (y >> 24) & 255;
212 *adds++ = (y >> 16) & 255;
213 *adds++ = (y >> 8) & 255;
214 *adds++ = y & 255;
215 }
216 *alist = NULL;
217 }
218
219 /* Wrong kind of literal address */
220
221 else
222 {
223 *error_num = HOST_NOT_FOUND;
224 return NULL;
225 }
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226
227/* Handle a host name */
228
229else
230 {
accf9211 231 int type = af == AF_INET ? T_A:T_AAAA;
8743d3ac 232 int rc = dns_lookup_timerwrap(dnsa, lname, type, NULL);
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233 int count = 0;
234
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235 lookup_dnssec_authenticated = NULL;
236
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237 switch(rc)
238 {
239 case DNS_SUCCEED: break;
240 case DNS_NOMATCH: *error_num = HOST_NOT_FOUND; return NULL;
241 case DNS_NODATA: *error_num = NO_DATA; return NULL;
242 case DNS_AGAIN: *error_num = TRY_AGAIN; return NULL;
243 default:
244 case DNS_FAIL: *error_num = NO_RECOVERY; return NULL;
245 }
246
8743d3ac 247 for (dns_record * rr = dns_next_rr(dnsa, &dnss, RESET_ANSWERS);
e1a3f32f 248 rr;
8743d3ac 249 rr = dns_next_rr(dnsa, &dnss, RESET_NEXT)) if (rr->type == type)
d7978c0f 250 count++;
e7726cbf 251
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252 yield = store_get(sizeof(struct hostent), FALSE);
253 alist = store_get((count + 1) * sizeof(char *), FALSE);
254 adds = store_get(count *alen, FALSE);
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255
256 yield->h_name = CS name;
257 yield->h_aliases = NULL;
258 yield->h_addrtype = af;
259 yield->h_length = alen;
260 yield->h_addr_list = CSS alist;
261
8743d3ac 262 for (dns_record * rr = dns_next_rr(dnsa, &dnss, RESET_ANSWERS);
e1a3f32f 263 rr;
8743d3ac 264 rr = dns_next_rr(dnsa, &dnss, RESET_NEXT)) if (rr->type == type)
e7726cbf 265 {
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266 int x[4];
267 dns_address *da;
8743d3ac 268 if (!(da = dns_address_from_rr(dnsa, rr))) break;
e7726cbf 269 *alist++ = adds;
d7978c0f 270 for (int n = host_aton(da->address, x), i = 0; i < n; i++)
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271 {
272 int y = x[i];
273 *adds++ = (y >> 24) & 255;
274 *adds++ = (y >> 16) & 255;
275 *adds++ = (y >> 8) & 255;
276 *adds++ = y & 255;
277 }
278 }
279 *alist = NULL;
280 }
281
282return yield;
283}
284
285
286
287/*************************************************
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288* Build chain of host items from list *
289*************************************************/
290
291/* This function builds a chain of host items from a textual list of host
292names. It does not do any lookups. If randomize is true, the chain is build in
293a randomized order. There may be multiple groups of independently randomized
294hosts; they are delimited by a host name consisting of just "+".
295
296Arguments:
297 anchor anchor for the chain
298 list text list
299 randomize TRUE for randomizing
300
301Returns: nothing
302*/
303
304void
55414b25 305host_build_hostlist(host_item **anchor, const uschar *list, BOOL randomize)
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306{
307int sep = 0;
308int fake_mx = MX_NONE; /* This value is actually -1 */
309uschar *name;
059ec3d9 310
8b455685 311if (!list) return;
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312if (randomize) fake_mx--; /* Start at -2 for randomizing */
313
314*anchor = NULL;
315
8b455685 316while ((name = string_nextinlist(&list, &sep, NULL, 0)))
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317 {
318 host_item *h;
319
320 if (name[0] == '+' && name[1] == 0) /* "+" delimits a randomized group */
321 { /* ignore if not randomizing */
322 if (randomize) fake_mx--;
323 continue;
324 }
325
f3ebb786 326 h = store_get(sizeof(host_item), FALSE);
55414b25 327 h->name = name;
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328 h->address = NULL;
329 h->port = PORT_NONE;
330 h->mx = fake_mx;
331 h->sort_key = randomize? (-fake_mx)*1000 + random_number(1000) : 0;
332 h->status = hstatus_unknown;
333 h->why = hwhy_unknown;
334 h->last_try = 0;
335
8b455685 336 if (!*anchor)
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337 {
338 h->next = NULL;
339 *anchor = h;
340 }
341 else
342 {
343 host_item *hh = *anchor;
344 if (h->sort_key < hh->sort_key)
345 {
346 h->next = hh;
347 *anchor = h;
348 }
349 else
350 {
8b455685 351 while (hh->next && h->sort_key >= hh->next->sort_key)
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352 hh = hh->next;
353 h->next = hh->next;
354 hh->next = h;
355 }
356 }
357 }
358}
359
360
361
362
363
364/*************************************************
365* Extract port from address string *
366*************************************************/
367
368/* In the spool file, and in the -oMa and -oMi options, a host plus port is
369given as an IP address followed by a dot and a port number. This function
370decodes this.
371
372An alternative format for the -oMa and -oMi options is [ip address]:port which
373is what Exim 4 uses for output, because it seems to becoming commonly used,
374whereas the dot form confuses some programs/people. So we recognize that form
375too.
376
377Argument:
378 address points to the string; if there is a port, the '.' in the string
379 is overwritten with zero to terminate the address; if the string
380 is in the [xxx]:ppp format, the address is shifted left and the
381 brackets are removed
382
383Returns: 0 if there is no port, else the port number. If there's a syntax
384 error, leave the incoming address alone, and return 0.
385*/
386
387int
7cd1141b 388host_address_extract_port(uschar *address)
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389{
390int port = 0;
391uschar *endptr;
392
393/* Handle the "bracketed with colon on the end" format */
394
395if (*address == '[')
396 {
397 uschar *rb = address + 1;
398 while (*rb != 0 && *rb != ']') rb++;
399 if (*rb++ == 0) return 0; /* Missing ]; leave invalid address */
400 if (*rb == ':')
401 {
402 port = Ustrtol(rb + 1, &endptr, 10);
403 if (*endptr != 0) return 0; /* Invalid port; leave invalid address */
404 }
405 else if (*rb != 0) return 0; /* Bad syntax; leave invalid address */
406 memmove(address, address + 1, rb - address - 2);
407 rb[-2] = 0;
408 }
409
410/* Handle the "dot on the end" format */
411
412else
413 {
414 int skip = -3; /* Skip 3 dots in IPv4 addresses */
415 address--;
416 while (*(++address) != 0)
417 {
418 int ch = *address;
419 if (ch == ':') skip = 0; /* Skip 0 dots in IPv6 addresses */
420 else if (ch == '.' && skip++ >= 0) break;
421 }
422 if (*address == 0) return 0;
423 port = Ustrtol(address + 1, &endptr, 10);
424 if (*endptr != 0) return 0; /* Invalid port; leave invalid address */
425 *address = 0;
426 }
427
428return port;
429}
430
431
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432/*************************************************
433* Get port from a host item's name *
434*************************************************/
435
436/* This function is called when finding the IP address for a host that is in a
437list of hosts explicitly configured, such as in the manualroute router, or in a
438fallback hosts list. We see if there is a port specification at the end of the
439host name, and if so, remove it. A minimum length of 3 is required for the
440original name; nothing shorter is recognized as having a port.
441
442We test for a name ending with a sequence of digits; if preceded by colon we
443have a port if the character before the colon is ] and the name starts with [
444or if there are no other colons in the name (i.e. it's not an IPv6 address).
445
446Arguments: pointer to the host item
447Returns: a port number or PORT_NONE
448*/
449
450int
451host_item_get_port(host_item *h)
452{
55414b25 453const uschar *p;
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454int port, x;
455int len = Ustrlen(h->name);
456
457if (len < 3 || (p = h->name + len - 1, !isdigit(*p))) return PORT_NONE;
458
459/* Extract potential port number */
460
461port = *p-- - '0';
462x = 10;
463
464while (p > h->name + 1 && isdigit(*p))
465 {
466 port += (*p-- - '0') * x;
467 x *= 10;
468 }
469
470/* The smallest value of p at this point is h->name + 1. */
471
472if (*p != ':') return PORT_NONE;
473
474if (p[-1] == ']' && h->name[0] == '[')
475 h->name = string_copyn(h->name + 1, p - h->name - 2);
476else if (Ustrchr(h->name, ':') == p)
477 h->name = string_copyn(h->name, p - h->name);
478else return PORT_NONE;
479
480DEBUG(D_route|D_host_lookup) debug_printf("host=%s port=%d\n", h->name, port);
481return port;
482}
483
484
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485
486#ifndef STAND_ALONE /* Omit when standalone testing */
487
488/*************************************************
489* Build sender_fullhost and sender_rcvhost *
490*************************************************/
491
492/* This function is called when sender_host_name and/or sender_helo_name
493have been set. Or might have been set - for a local message read off the spool
494they won't be. In that case, do nothing. Otherwise, set up the fullhost string
495as follows:
496
497(a) No sender_host_name or sender_helo_name: "[ip address]"
498(b) Just sender_host_name: "host_name [ip address]"
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499(c) Just sender_helo_name: "(helo_name) [ip address]" unless helo is IP
500 in which case: "[ip address}"
501(d) The two are identical: "host_name [ip address]" includes helo = IP
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502(e) The two are different: "host_name (helo_name) [ip address]"
503
504If log_incoming_port is set, the sending host's port number is added to the IP
505address.
506
507This function also builds sender_rcvhost for use in Received: lines, whose
508syntax is a bit different. This value also includes the RFC 1413 identity.
509There wouldn't be two different variables if I had got all this right in the
510first place.
511
512Because this data may survive over more than one incoming SMTP message, it has
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513to be in permanent store. However, STARTTLS has to be forgotten and redone
514on a multi-message conn, so this will be called once per message then. Hence
515we use malloc, so we can free.
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516
517Arguments: none
518Returns: nothing
519*/
520
521void
522host_build_sender_fullhost(void)
523{
82c19f95 524BOOL show_helo = TRUE;
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525uschar * address, * fullhost, * rcvhost;
526rmark reset_point;
82c19f95 527int len;
059ec3d9 528
2d0dc929 529if (!sender_host_address) return;
059ec3d9 530
f3ebb786 531reset_point = store_mark();
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532
533/* Set up address, with or without the port. After discussion, it seems that
534the only format that doesn't cause trouble is [aaaa]:pppp. However, we can't
535use this directly as the first item for Received: because it ain't an RFC 2822
536domain. Sigh. */
537
538address = string_sprintf("[%s]:%d", sender_host_address, sender_host_port);
6c6d6e48 539if (!LOGGING(incoming_port) || sender_host_port <= 0)
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540 *(Ustrrchr(address, ':')) = 0;
541
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542/* If there's no EHLO/HELO data, we can't show it. */
543
2d0dc929 544if (!sender_helo_name) show_helo = FALSE;
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545
546/* If HELO/EHLO was followed by an IP literal, it's messy because of two
547features of IPv6. Firstly, there's the "IPv6:" prefix (Exim is liberal and
548doesn't require this, for historical reasons). Secondly, IPv6 addresses may not
4c04137d 549be given in canonical form, so we have to canonicalize them before comparing. As
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550it happens, the code works for both IPv4 and IPv6. */
551
552else if (sender_helo_name[0] == '[' &&
553 sender_helo_name[(len=Ustrlen(sender_helo_name))-1] == ']')
554 {
555 int offset = 1;
556 uschar *helo_ip;
557
558 if (strncmpic(sender_helo_name + 1, US"IPv6:", 5) == 0) offset += 5;
559 if (strncmpic(sender_helo_name + 1, US"IPv4:", 5) == 0) offset += 5;
560
561 helo_ip = string_copyn(sender_helo_name + offset, len - offset - 1);
562
563 if (string_is_ip_address(helo_ip, NULL) != 0)
564 {
565 int x[4], y[4];
566 int sizex, sizey;
567 uschar ipx[48], ipy[48]; /* large enough for full IPv6 */
568
569 sizex = host_aton(helo_ip, x);
570 sizey = host_aton(sender_host_address, y);
571
572 (void)host_nmtoa(sizex, x, -1, ipx, ':');
573 (void)host_nmtoa(sizey, y, -1, ipy, ':');
574
575 if (strcmpic(ipx, ipy) == 0) show_helo = FALSE;
576 }
577 }
578
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579/* Host name is not verified */
580
acec9514 581if (!sender_host_name)
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582 {
583 uschar *portptr = Ustrstr(address, "]:");
acec9514 584 gstring * g;
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585 int adlen; /* Sun compiler doesn't like ++ in initializers */
586
acec9514 587 adlen = portptr ? (++portptr - address) : Ustrlen(address);
a5c60e3c 588 fullhost = sender_helo_name
acec9514
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589 ? string_sprintf("(%s) %s", sender_helo_name, address)
590 : address;
059ec3d9 591
acec9514 592 g = string_catn(NULL, address, adlen);
059ec3d9 593
2d0dc929 594 if (sender_ident || show_helo || portptr)
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595 {
596 int firstptr;
acec9514
JH
597 g = string_catn(g, US" (", 2);
598 firstptr = g->ptr;
059ec3d9 599
acec9514
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600 if (portptr)
601 g = string_append(g, 2, US"port=", portptr + 1);
059ec3d9 602
82c19f95 603 if (show_helo)
acec9514
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604 g = string_append(g, 2,
605 firstptr == g->ptr ? US"helo=" : US" helo=", sender_helo_name);
059ec3d9 606
acec9514
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607 if (sender_ident)
608 g = string_append(g, 2,
609 firstptr == g->ptr ? US"ident=" : US" ident=", sender_ident);
059ec3d9 610
acec9514 611 g = string_catn(g, US")", 1);
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612 }
613
a5c60e3c 614 rcvhost = string_from_gstring(g);
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615 }
616
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617/* Host name is known and verified. Unless we've already found that the HELO
618data matches the IP address, compare it with the name. */
059ec3d9
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619
620else
621 {
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622 if (show_helo && strcmpic(sender_host_name, sender_helo_name) == 0)
623 show_helo = FALSE;
5dd9625b 624
82c19f95 625 if (show_helo)
059ec3d9 626 {
a5c60e3c 627 fullhost = string_sprintf("%s (%s) %s", sender_host_name,
059ec3d9 628 sender_helo_name, address);
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629 rcvhost = sender_ident
630 ? string_sprintf("%s\n\t(%s helo=%s ident=%s)", sender_host_name,
631 address, sender_helo_name, sender_ident)
632 : string_sprintf("%s (%s helo=%s)", sender_host_name,
633 address, sender_helo_name);
059ec3d9 634 }
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635 else
636 {
a5c60e3c
JH
637 fullhost = string_sprintf("%s %s", sender_host_name, address);
638 rcvhost = sender_ident
639 ? string_sprintf("%s (%s ident=%s)", sender_host_name, address,
640 sender_ident)
641 : string_sprintf("%s (%s)", sender_host_name, address);
82c19f95 642 }
059ec3d9
PH
643 }
644
f3ebb786
JH
645sender_fullhost = string_copy_perm(fullhost, TRUE);
646sender_rcvhost = string_copy_perm(rcvhost, TRUE);
a5c60e3c
JH
647
648store_reset(reset_point);
059ec3d9
PH
649
650DEBUG(D_host_lookup) debug_printf("sender_fullhost = %s\n", sender_fullhost);
651DEBUG(D_host_lookup) debug_printf("sender_rcvhost = %s\n", sender_rcvhost);
652}
653
654
655
656/*************************************************
657* Build host+ident message *
658*************************************************/
659
660/* Used when logging rejections and various ACL and SMTP incidents. The text
661return depends on whether sender_fullhost and sender_ident are set or not:
662
663 no ident, no host => U=unknown
664 no ident, host set => H=sender_fullhost
665 ident set, no host => U=ident
666 ident set, host set => H=sender_fullhost U=ident
667
f3ebb786
JH
668Use taint-unchecked routines on the assumption we'll never expand the results.
669
059ec3d9
PH
670Arguments:
671 useflag TRUE if first item to be flagged (H= or U=); if there are two
672 items, the second is always flagged
673
674Returns: pointer to a string in big_buffer
675*/
676
677uschar *
678host_and_ident(BOOL useflag)
679{
8b455685 680if (!sender_fullhost)
f3ebb786 681 string_format_nt(big_buffer, big_buffer_size, "%s%s", useflag ? "U=" : "",
8b455685 682 sender_ident ? sender_ident : US"unknown");
059ec3d9
PH
683else
684 {
8b455685
JH
685 uschar * flag = useflag ? US"H=" : US"";
686 uschar * iface = US"";
687 if (LOGGING(incoming_interface) && interface_address)
059ec3d9 688 iface = string_sprintf(" I=[%s]:%d", interface_address, interface_port);
8b455685 689 if (sender_ident)
f3ebb786 690 string_format_nt(big_buffer, big_buffer_size, "%s%s%s U=%s",
059ec3d9 691 flag, sender_fullhost, iface, sender_ident);
8b455685 692 else
f3ebb786 693 string_format_nt(big_buffer, big_buffer_size, "%s%s%s",
8b455685 694 flag, sender_fullhost, iface);
059ec3d9
PH
695 }
696return big_buffer;
697}
698
699#endif /* STAND_ALONE */
700
701
702
703
704/*************************************************
705* Build list of local interfaces *
706*************************************************/
707
708/* This function interprets the contents of the local_interfaces or
709extra_local_interfaces options, and creates an ip_address_item block for each
710item on the list. There is no special interpretation of any IP addresses; in
711particular, 0.0.0.0 and ::0 are returned without modification. If any address
712includes a port, it is set in the block. Otherwise the port value is set to
713zero.
714
715Arguments:
716 list the list
717 name the name of the option being expanded
718
719Returns: a chain of ip_address_items, each containing to a textual
720 version of an IP address, and a port number (host order) or
721 zero if no port was given with the address
722*/
723
724ip_address_item *
55414b25 725host_build_ifacelist(const uschar *list, uschar *name)
059ec3d9
PH
726{
727int sep = 0;
728uschar *s;
b891534f 729ip_address_item * yield = NULL, * last = NULL, * next;
ba74fb8d 730BOOL taint = is_tainted(list);
059ec3d9 731
b891534f 732while ((s = string_nextinlist(&list, &sep, NULL, 0)))
059ec3d9 733 {
7e66e54d 734 int ipv;
7cd1141b 735 int port = host_address_extract_port(s); /* Leaves just the IP address */
b891534f
JH
736
737 if (!(ipv = string_is_ip_address(s, NULL)))
059ec3d9
PH
738 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Malformed IP address \"%s\" in %s",
739 s, name);
740
7e66e54d
PH
741 /* Skip IPv6 addresses if IPv6 is disabled. */
742
743 if (disable_ipv6 && ipv == 6) continue;
744
059ec3d9
PH
745 /* This use of strcpy() is OK because we have checked that s is a valid IP
746 address above. The field in the ip_address_item is large enough to hold an
747 IPv6 address. */
748
ba74fb8d 749 next = store_get(sizeof(ip_address_item), taint);
059ec3d9
PH
750 next->next = NULL;
751 Ustrcpy(next->address, s);
752 next->port = port;
753 next->v6_include_v4 = FALSE;
254f38d1 754 next->log = NULL;
059ec3d9 755
b891534f
JH
756 if (!yield)
757 yield = last = next;
758 else
059ec3d9
PH
759 {
760 last->next = next;
761 last = next;
762 }
763 }
764
765return yield;
766}
767
768
769
770
771
772/*************************************************
773* Find addresses on local interfaces *
774*************************************************/
775
776/* This function finds the addresses of local IP interfaces. These are used
777when testing for routing to the local host. As the function may be called more
778than once, the list is preserved in permanent store, pointed to by a static
779variable, to save doing the work more than once per process.
780
781The generic list of interfaces is obtained by calling host_build_ifacelist()
782for local_interfaces and extra_local_interfaces. This list scanned to remove
783duplicates (which may exist with different ports - not relevant here). If
784either of the wildcard IP addresses (0.0.0.0 and ::0) are encountered, they are
785replaced by the appropriate (IPv4 or IPv6) list of actual local interfaces,
786obtained from os_find_running_interfaces().
787
788Arguments: none
789Returns: a chain of ip_address_items, each containing to a textual
790 version of an IP address; the port numbers are not relevant
791*/
792
793
794/* First, a local subfunction to add an interface to a list in permanent store,
795but only if there isn't a previous copy of that address on the list. */
796
797static ip_address_item *
798add_unique_interface(ip_address_item *list, ip_address_item *ipa)
799{
800ip_address_item *ipa2;
d7978c0f 801for (ipa2 = list; ipa2; ipa2 = ipa2->next)
059ec3d9 802 if (Ustrcmp(ipa2->address, ipa->address) == 0) return list;
f3ebb786 803ipa2 = store_get_perm(sizeof(ip_address_item), FALSE);
059ec3d9
PH
804*ipa2 = *ipa;
805ipa2->next = list;
806return ipa2;
807}
808
809
810/* This is the globally visible function */
811
812ip_address_item *
813host_find_interfaces(void)
814{
815ip_address_item *running_interfaces = NULL;
816
817if (local_interface_data == NULL)
818 {
f3ebb786 819 void *reset_item = store_mark();
55414b25 820 ip_address_item *dlist = host_build_ifacelist(CUS local_interfaces,
059ec3d9 821 US"local_interfaces");
55414b25 822 ip_address_item *xlist = host_build_ifacelist(CUS extra_local_interfaces,
059ec3d9
PH
823 US"extra_local_interfaces");
824 ip_address_item *ipa;
825
d7978c0f
JH
826 if (!dlist) dlist = xlist;
827 else
059ec3d9 828 {
d7978c0f 829 for (ipa = dlist; ipa->next; ipa = ipa->next) ;
059ec3d9
PH
830 ipa->next = xlist;
831 }
832
d7978c0f 833 for (ipa = dlist; ipa; ipa = ipa->next)
059ec3d9
PH
834 {
835 if (Ustrcmp(ipa->address, "0.0.0.0") == 0 ||
836 Ustrcmp(ipa->address, "::0") == 0)
837 {
059ec3d9 838 BOOL ipv6 = ipa->address[0] == ':';
d7978c0f 839 if (!running_interfaces)
059ec3d9 840 running_interfaces = os_find_running_interfaces();
d7978c0f 841 for (ip_address_item * ipa2 = running_interfaces; ipa2; ipa2 = ipa2->next)
059ec3d9
PH
842 if ((Ustrchr(ipa2->address, ':') != NULL) == ipv6)
843 local_interface_data = add_unique_interface(local_interface_data,
d7978c0f 844 ipa2);
059ec3d9
PH
845 }
846 else
847 {
848 local_interface_data = add_unique_interface(local_interface_data, ipa);
849 DEBUG(D_interface)
850 {
851 debug_printf("Configured local interface: address=%s", ipa->address);
852 if (ipa->port != 0) debug_printf(" port=%d", ipa->port);
853 debug_printf("\n");
854 }
855 }
856 }
857 store_reset(reset_item);
858 }
859
860return local_interface_data;
861}
862
863
864
865
866
867/*************************************************
868* Convert network IP address to text *
869*************************************************/
870
871/* Given an IPv4 or IPv6 address in binary, convert it to a text
872string and return the result in a piece of new store. The address can
873either be given directly, or passed over in a sockaddr structure. Note
874that this isn't the converse of host_aton() because of byte ordering
875differences. See host_nmtoa() below.
876
877Arguments:
878 type if < 0 then arg points to a sockaddr, else
879 either AF_INET or AF_INET6
880 arg points to a sockaddr if type is < 0, or
881 points to an IPv4 address (32 bits), or
882 points to an IPv6 address (128 bits),
883 in both cases, in network byte order
884 buffer if NULL, the result is returned in gotten store;
885 else points to a buffer to hold the answer
886 portptr points to where to put the port number, if non NULL; only
887 used when type < 0
888
889Returns: pointer to character string
890*/
891
892uschar *
893host_ntoa(int type, const void *arg, uschar *buffer, int *portptr)
894{
895uschar *yield;
896
897/* The new world. It is annoying that we have to fish out the address from
898different places in the block, depending on what kind of address it is. It
899is also a pain that inet_ntop() returns a const uschar *, whereas the IPv4
900function inet_ntoa() returns just uschar *, and some picky compilers insist
901on warning if one assigns a const uschar * to a uschar *. Hence the casts. */
902
903#if HAVE_IPV6
904uschar addr_buffer[46];
905if (type < 0)
906 {
907 int family = ((struct sockaddr *)arg)->sa_family;
908 if (family == AF_INET6)
909 {
910 struct sockaddr_in6 *sk = (struct sockaddr_in6 *)arg;
5903c6ff 911 yield = US inet_ntop(family, &(sk->sin6_addr), CS addr_buffer,
059ec3d9
PH
912 sizeof(addr_buffer));
913 if (portptr != NULL) *portptr = ntohs(sk->sin6_port);
914 }
915 else
916 {
917 struct sockaddr_in *sk = (struct sockaddr_in *)arg;
5903c6ff 918 yield = US inet_ntop(family, &(sk->sin_addr), CS addr_buffer,
059ec3d9
PH
919 sizeof(addr_buffer));
920 if (portptr != NULL) *portptr = ntohs(sk->sin_port);
921 }
922 }
923else
924 {
5903c6ff 925 yield = US inet_ntop(type, arg, CS addr_buffer, sizeof(addr_buffer));
059ec3d9
PH
926 }
927
928/* If the result is a mapped IPv4 address, show it in V4 format. */
929
930if (Ustrncmp(yield, "::ffff:", 7) == 0) yield += 7;
931
932#else /* HAVE_IPV6 */
933
934/* The old world */
935
936if (type < 0)
937 {
938 yield = US inet_ntoa(((struct sockaddr_in *)arg)->sin_addr);
939 if (portptr != NULL) *portptr = ntohs(((struct sockaddr_in *)arg)->sin_port);
940 }
941else
942 yield = US inet_ntoa(*((struct in_addr *)arg));
943#endif
944
945/* If there is no buffer, put the string into some new store. */
946
f8d78f74 947if (!buffer) buffer = store_get(46, FALSE);
059ec3d9
PH
948
949/* Callers of this function with a non-NULL buffer must ensure that it is
950large enough to hold an IPv6 address, namely, at least 46 bytes. That's what
f8d78f74
JH
951makes this use of strcpy() OK.
952If the library returned apparently an apparently tainted string, clean it;
953we trust IP addresses. */
059ec3d9 954
f8d78f74 955string_format_nt(buffer, 46, "%s", yield);
059ec3d9
PH
956return buffer;
957}
958
959
960
961
962/*************************************************
963* Convert address text to binary *
964*************************************************/
965
966/* Given the textual form of an IP address, convert it to binary in an
967array of ints. IPv4 addresses occupy one int; IPv6 addresses occupy 4 ints.
968The result has the first byte in the most significant byte of the first int. In
969other words, the result is not in network byte order, but in host byte order.
970As a result, this is not the converse of host_ntoa(), which expects network
971byte order. See host_nmtoa() below.
972
973Arguments:
974 address points to the textual address, checked for syntax
975 bin points to an array of 4 ints
976
977Returns: the number of ints used
978*/
979
980int
55414b25 981host_aton(const uschar *address, int *bin)
059ec3d9
PH
982{
983int x[4];
984int v4offset = 0;
985
8e669ac1 986/* Handle IPv6 address, which may end with an IPv4 address. It may also end
7e634d24
PH
987with a "scope", introduced by a percent sign. This code is NOT enclosed in #if
988HAVE_IPV6 in order that IPv6 addresses are recognized even if IPv6 is not
989supported. */
059ec3d9
PH
990
991if (Ustrchr(address, ':') != NULL)
992 {
55414b25
JH
993 const uschar *p = address;
994 const uschar *component[8];
059ec3d9
PH
995 BOOL ipv4_ends = FALSE;
996 int ci = 0;
997 int nulloffset = 0;
998 int v6count = 8;
999 int i;
1000
1001 /* If the address starts with a colon, it will start with two colons.
1002 Just lose the first one, which will leave a null first component. */
8e669ac1 1003
059ec3d9
PH
1004 if (*p == ':') p++;
1005
8e669ac1
PH
1006 /* Split the address into components separated by colons. The input address
1007 is supposed to be checked for syntax. There was a case where this was
1008 overlooked; to guard against that happening again, check here and crash if
7e634d24 1009 there are too many components. */
059ec3d9 1010
7e634d24 1011 while (*p != 0 && *p != '%')
059ec3d9 1012 {
7e634d24 1013 int len = Ustrcspn(p, ":%");
059ec3d9 1014 if (len == 0) nulloffset = ci;
8e669ac1 1015 if (ci > 7) log_write(0, LOG_MAIN|LOG_PANIC_DIE,
b975ba52 1016 "Internal error: invalid IPv6 address \"%s\" passed to host_aton()",
8e669ac1 1017 address);
059ec3d9
PH
1018 component[ci++] = p;
1019 p += len;
1020 if (*p == ':') p++;
1021 }
1022
1023 /* If the final component contains a dot, it is a trailing v4 address.
1024 As the syntax is known to be checked, just set up for a trailing
1025 v4 address and restrict the v6 part to 6 components. */
1026
1027 if (Ustrchr(component[ci-1], '.') != NULL)
1028 {
1029 address = component[--ci];
1030 ipv4_ends = TRUE;
1031 v4offset = 3;
1032 v6count = 6;
1033 }
1034
1035 /* If there are fewer than 6 or 8 components, we have to insert some
1036 more empty ones in the middle. */
1037
1038 if (ci < v6count)
1039 {
1040 int insert_count = v6count - ci;
1041 for (i = v6count-1; i > nulloffset + insert_count; i--)
1042 component[i] = component[i - insert_count];
1043 while (i > nulloffset) component[i--] = US"";
1044 }
1045
1046 /* Now turn the components into binary in pairs and bung them
1047 into the vector of ints. */
1048
1049 for (i = 0; i < v6count; i += 2)
1050 bin[i/2] = (Ustrtol(component[i], NULL, 16) << 16) +
1051 Ustrtol(component[i+1], NULL, 16);
1052
1053 /* If there was no terminating v4 component, we are done. */
1054
1055 if (!ipv4_ends) return 4;
1056 }
1057
1058/* Handle IPv4 address */
1059
ff790e47 1060(void)sscanf(CS address, "%d.%d.%d.%d", x, x+1, x+2, x+3);
13559da6 1061bin[v4offset] = ((uint)x[0] << 24) + (x[1] << 16) + (x[2] << 8) + x[3];
059ec3d9
PH
1062return v4offset+1;
1063}
1064
1065
1066/*************************************************
1067* Apply mask to an IP address *
1068*************************************************/
1069
1070/* Mask an address held in 1 or 4 ints, with the ms bit in the ms bit of the
1071first int, etc.
1072
1073Arguments:
1074 count the number of ints
1075 binary points to the ints to be masked
1076 mask the count of ms bits to leave, or -1 if no masking
1077
1078Returns: nothing
1079*/
1080
1081void
1082host_mask(int count, int *binary, int mask)
1083{
059ec3d9 1084if (mask < 0) mask = 99999;
d7978c0f 1085for (int i = 0; i < count; i++)
059ec3d9
PH
1086 {
1087 int wordmask;
1088 if (mask == 0) wordmask = 0;
1089 else if (mask < 32)
1090 {
13559da6 1091 wordmask = (uint)(-1) << (32 - mask);
059ec3d9
PH
1092 mask = 0;
1093 }
1094 else
1095 {
1096 wordmask = -1;
1097 mask -= 32;
1098 }
1099 binary[i] &= wordmask;
1100 }
1101}
1102
1103
1104
1105
1106/*************************************************
1107* Convert masked IP address in ints to text *
1108*************************************************/
1109
1110/* We can't use host_ntoa() because it assumes the binary values are in network
1111byte order, and these are the result of host_aton(), which puts them in ints in
1112host byte order. Also, we really want IPv6 addresses to be in a canonical
6f0c9a4f
PH
1113format, so we output them with no abbreviation. In a number of cases we can't
1114use the normal colon separator in them because it terminates keys in lsearch
8e669ac1 1115files, so we want to use dot instead. There's an argument that specifies what
6f0c9a4f 1116to use for IPv6 addresses.
059ec3d9
PH
1117
1118Arguments:
1119 count 1 or 4 (number of ints)
1120 binary points to the ints
1121 mask mask value; if < 0 don't add to result
1122 buffer big enough to hold the result
8e669ac1 1123 sep component separator character for IPv6 addresses
059ec3d9
PH
1124
1125Returns: the number of characters placed in buffer, not counting
1126 the final nul.
1127*/
1128
1129int
6f0c9a4f 1130host_nmtoa(int count, int *binary, int mask, uschar *buffer, int sep)
059ec3d9 1131{
d7978c0f 1132int j;
059ec3d9
PH
1133uschar *tt = buffer;
1134
1135if (count == 1)
1136 {
1137 j = binary[0];
d7978c0f 1138 for (int i = 24; i >= 0; i -= 8)
fc4a7f70 1139 tt += sprintf(CS tt, "%d.", (j >> i) & 255);
059ec3d9
PH
1140 }
1141else
d7978c0f 1142 for (int i = 0; i < 4; i++)
059ec3d9
PH
1143 {
1144 j = binary[i];
fc4a7f70 1145 tt += sprintf(CS tt, "%04x%c%04x%c", (j >> 16) & 0xffff, sep, j & 0xffff, sep);
059ec3d9 1146 }
059ec3d9 1147
6f0c9a4f 1148tt--; /* lose final separator */
059ec3d9
PH
1149
1150if (mask < 0)
1151 *tt = 0;
1152else
5976eb99 1153 tt += sprintf(CS tt, "/%d", mask);
059ec3d9
PH
1154
1155return tt - buffer;
1156}
1157
1158
fc4a7f70
JH
1159/* Like host_nmtoa() but: ipv6-only, canonical output, no mask
1160
1161Arguments:
1162 binary points to the ints
1163 buffer big enough to hold the result
1164
1165Returns: the number of characters placed in buffer, not counting
1166 the final nul.
1167*/
1168
1169int
1170ipv6_nmtoa(int * binary, uschar * buffer)
1171{
1172int i, j, k;
1173uschar * c = buffer;
39755c16 1174uschar * d = NULL; /* shut insufficiently "clever" compiler up */
fc4a7f70
JH
1175
1176for (i = 0; i < 4; i++)
1177 { /* expand to text */
1178 j = binary[i];
1179 c += sprintf(CS c, "%x:%x:", (j >> 16) & 0xffff, j & 0xffff);
1180 }
1181
1182for (c = buffer, k = -1, i = 0; i < 8; i++)
1183 { /* find longest 0-group sequence */
1184 if (*c == '0') /* must be "0:" */
1185 {
1186 uschar * s = c;
1187 j = i;
1188 while (c[2] == '0') i++, c += 2;
1189 if (i-j > k)
1190 {
1191 k = i-j; /* length of sequence */
1192 d = s; /* start of sequence */
1193 }
1194 }
1195 while (*++c != ':') ;
1196 c++;
1197 }
1198
1199c[-1] = '\0'; /* drop trailing colon */
1200
1201/* debug_printf("%s: D k %d <%s> <%s>\n", __FUNCTION__, k, d, d + 2*(k+1)); */
1202if (k >= 0)
1203 { /* collapse */
1204 c = d + 2*(k+1);
1205 if (d == buffer) c--; /* need extra colon */
1206 *d++ = ':'; /* 1st 0 */
39755c16 1207 while ((*d++ = *c++)) ;
fc4a7f70
JH
1208 }
1209else
1210 d = c;
1211
1212return d - buffer;
1213}
1214
1215
059ec3d9
PH
1216
1217/*************************************************
1218* Check port for tls_on_connect *
1219*************************************************/
1220
1221/* This function checks whether a given incoming port is configured for tls-
1222on-connect. It is called from the daemon and from inetd handling. If the global
1223option tls_on_connect is already set, all ports operate this way. Otherwise, we
1224check the tls_on_connect_ports option for a list of ports.
1225
1226Argument: a port number
1227Returns: TRUE or FALSE
1228*/
1229
1230BOOL
1231host_is_tls_on_connect_port(int port)
1232{
1233int sep = 0;
1234uschar buffer[32];
55414b25 1235const uschar *list = tls_in.on_connect_ports;
059ec3d9 1236uschar *s;
071c51f7 1237uschar *end;
059ec3d9 1238
817d9f57 1239if (tls_in.on_connect) return TRUE;
059ec3d9 1240
071c51f7
JH
1241while ((s = string_nextinlist(&list, &sep, buffer, sizeof(buffer))))
1242 if (Ustrtol(s, &end, 10) == port)
1243 return TRUE;
059ec3d9
PH
1244
1245return FALSE;
1246}
1247
1248
1249
1250/*************************************************
1251* Check whether host is in a network *
1252*************************************************/
1253
1254/* This function checks whether a given IP address matches a pattern that
1255represents either a single host, or a network (using CIDR notation). The caller
1256of this function must check the syntax of the arguments before calling it.
1257
1258Arguments:
1259 host string representation of the ip-address to check
1260 net string representation of the network, with optional CIDR mask
1261 maskoffset offset to the / that introduces the mask in the key
1262 zero if there is no mask
1263
1264Returns:
1265 TRUE the host is inside the network
1266 FALSE the host is NOT inside the network
1267*/
1268
1269BOOL
55414b25 1270host_is_in_net(const uschar *host, const uschar *net, int maskoffset)
059ec3d9 1271{
059ec3d9
PH
1272int address[4];
1273int incoming[4];
1274int mlen;
1275int size = host_aton(net, address);
1276int insize;
1277
1278/* No mask => all bits to be checked */
1279
1280if (maskoffset == 0) mlen = 99999; /* Big number */
1281 else mlen = Uatoi(net + maskoffset + 1);
1282
1283/* Convert the incoming address to binary. */
1284
1285insize = host_aton(host, incoming);
1286
1287/* Convert IPv4 addresses given in IPv6 compatible mode, which represent
1288 connections from IPv4 hosts to IPv6 hosts, that is, addresses of the form
1289 ::ffff:<v4address>, to IPv4 format. */
1290
1291if (insize == 4 && incoming[0] == 0 && incoming[1] == 0 &&
1292 incoming[2] == 0xffff)
1293 {
1294 insize = 1;
1295 incoming[0] = incoming[3];
1296 }
1297
1298/* No match if the sizes don't agree. */
1299
1300if (insize != size) return FALSE;
1301
1302/* Else do the masked comparison. */
1303
d7978c0f 1304for (int i = 0; i < size; i++)
059ec3d9
PH
1305 {
1306 int mask;
1307 if (mlen == 0) mask = 0;
1308 else if (mlen < 32)
1309 {
13559da6 1310 mask = (uint)(-1) << (32 - mlen);
059ec3d9
PH
1311 mlen = 0;
1312 }
1313 else
1314 {
1315 mask = -1;
1316 mlen -= 32;
1317 }
1318 if ((incoming[i] & mask) != (address[i] & mask)) return FALSE;
1319 }
1320
1321return TRUE;
1322}
1323
1324
1325
1326/*************************************************
1327* Scan host list for local hosts *
1328*************************************************/
1329
1330/* Scan through a chain of addresses and check whether any of them is the
1331address of an interface on the local machine. If so, remove that address and
1332any previous ones with the same MX value, and all subsequent ones (which will
1333have greater or equal MX values) from the chain. Note: marking them as unusable
1334is NOT the right thing to do because it causes the hosts not to be used for
1335other domains, for which they may well be correct.
1336
1337The hosts may be part of a longer chain; we only process those between the
1338initial pointer and the "last" pointer.
1339
1340There is also a list of "pseudo-local" host names which are checked against the
1341host names. Any match causes that host item to be treated the same as one which
1342matches a local IP address.
1343
1344If the very first host is a local host, then all MX records had a precedence
1345greater than or equal to that of the local host. Either there's a problem in
1346the DNS, or an apparently remote name turned out to be an abbreviation for the
1347local host. Give a specific return code, and let the caller decide what to do.
1348Otherwise, give a success code if at least one host address has been found.
1349
1350Arguments:
1351 host pointer to the first host in the chain
1352 lastptr pointer to pointer to the last host in the chain (may be updated)
1353 removed if not NULL, set TRUE if some local addresses were removed
1354 from the list
1355
1356Returns:
1357 HOST_FOUND if there is at least one host with an IP address on the chain
1358 and an MX value less than any MX value associated with the
1359 local host
1360 HOST_FOUND_LOCAL if a local host is among the lowest-numbered MX hosts; when
1361 the host addresses were obtained from A records or
1362 gethostbyname(), the MX values are set to -1.
1363 HOST_FIND_FAILED if no valid hosts with set IP addresses were found
1364*/
1365
1366int
1367host_scan_for_local_hosts(host_item *host, host_item **lastptr, BOOL *removed)
1368{
1369int yield = HOST_FIND_FAILED;
1370host_item *last = *lastptr;
1371host_item *prev = NULL;
1372host_item *h;
1373
1374if (removed != NULL) *removed = FALSE;
1375
1376if (local_interface_data == NULL) local_interface_data = host_find_interfaces();
1377
1378for (h = host; h != last->next; h = h->next)
1379 {
1380 #ifndef STAND_ALONE
1381 if (hosts_treat_as_local != NULL)
1382 {
1383 int rc;
55414b25 1384 const uschar *save = deliver_domain;
059ec3d9 1385 deliver_domain = h->name; /* set $domain */
55414b25 1386 rc = match_isinlist(string_copylc(h->name), CUSS &hosts_treat_as_local, 0,
059ec3d9
PH
1387 &domainlist_anchor, NULL, MCL_DOMAIN, TRUE, NULL);
1388 deliver_domain = save;
1389 if (rc == OK) goto FOUND_LOCAL;
1390 }
1391 #endif
1392
1393 /* It seems that on many operating systems, 0.0.0.0 is treated as a synonym
1394 for 127.0.0.1 and refers to the local host. We therefore force it always to
1395 be treated as local. */
1396
1397 if (h->address != NULL)
1398 {
059ec3d9 1399 if (Ustrcmp(h->address, "0.0.0.0") == 0) goto FOUND_LOCAL;
d7978c0f 1400 for (ip_address_item * ip = local_interface_data; ip; ip = ip->next)
059ec3d9
PH
1401 if (Ustrcmp(h->address, ip->address) == 0) goto FOUND_LOCAL;
1402 yield = HOST_FOUND; /* At least one remote address has been found */
1403 }
1404
1405 /* Update prev to point to the last host item before any that have
1406 the same MX value as the one we have just considered. */
1407
1408 if (h->next == NULL || h->next->mx != h->mx) prev = h;
1409 }
1410
1411return yield; /* No local hosts found: return HOST_FOUND or HOST_FIND_FAILED */
1412
1413/* A host whose IP address matches a local IP address, or whose name matches
1414something in hosts_treat_as_local has been found. */
1415
1416FOUND_LOCAL:
1417
1418if (prev == NULL)
1419 {
1420 HDEBUG(D_host_lookup) debug_printf((h->mx >= 0)?
1421 "local host has lowest MX\n" :
1422 "local host found for non-MX address\n");
1423 return HOST_FOUND_LOCAL;
1424 }
1425
1426HDEBUG(D_host_lookup)
1427 {
1428 debug_printf("local host in host list - removed hosts:\n");
1429 for (h = prev->next; h != last->next; h = h->next)
1430 debug_printf(" %s %s %d\n", h->name, h->address, h->mx);
1431 }
1432
1433if (removed != NULL) *removed = TRUE;
1434prev->next = last->next;
1435*lastptr = prev;
1436return yield;
1437}
1438
1439
1440
1441
1442/*************************************************
1443* Remove duplicate IPs in host list *
1444*************************************************/
1445
1446/* You would think that administrators could set up their DNS records so that
1447one ended up with a list of unique IP addresses after looking up A or MX
1448records, but apparently duplication is common. So we scan such lists and
1449remove the later duplicates. Note that we may get lists in which some host
1450addresses are not set.
1451
1452Arguments:
1453 host pointer to the first host in the chain
1454 lastptr pointer to pointer to the last host in the chain (may be updated)
1455
1456Returns: nothing
1457*/
1458
1459static void
1460host_remove_duplicates(host_item *host, host_item **lastptr)
1461{
1462while (host != *lastptr)
1463 {
1464 if (host->address != NULL)
1465 {
1466 host_item *h = host;
1467 while (h != *lastptr)
1468 {
1469 if (h->next->address != NULL &&
1470 Ustrcmp(h->next->address, host->address) == 0)
1471 {
1472 DEBUG(D_host_lookup) debug_printf("duplicate IP address %s (MX=%d) "
1473 "removed\n", host->address, h->next->mx);
1474 if (h->next == *lastptr) *lastptr = h;
1475 h->next = h->next->next;
1476 }
1477 else h = h->next;
1478 }
1479 }
1480 /* If the last item was removed, host may have become == *lastptr */
1481 if (host != *lastptr) host = host->next;
1482 }
1483}
1484
1485
1486
1487
1488/*************************************************
1489* Find sender host name by gethostbyaddr() *
1490*************************************************/
1491
1492/* This used to be the only way it was done, but it turns out that not all
1493systems give aliases for calls to gethostbyaddr() - or one of the modern
1494equivalents like getipnodebyaddr(). Fortunately, multiple PTR records are rare,
1495but they can still exist. This function is now used only when a DNS lookup of
1496the IP address fails, in order to give access to /etc/hosts.
1497
1498Arguments: none
1499Returns: OK, DEFER, FAIL
1500*/
1501
1502static int
1503host_name_lookup_byaddr(void)
1504{
d70fc283 1505struct hostent * hosts;
059ec3d9 1506struct in_addr addr;
f2cb6292 1507unsigned long time_msec = 0; /* init to quieten dumb static analysis */
846430d9
JH
1508
1509if (slow_lookup_log) time_msec = get_time_in_ms();
059ec3d9
PH
1510
1511/* Lookup on IPv6 system */
1512
1513#if HAVE_IPV6
1514if (Ustrchr(sender_host_address, ':') != NULL)
1515 {
1516 struct in6_addr addr6;
1517 if (inet_pton(AF_INET6, CS sender_host_address, &addr6) != 1)
1518 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "unable to parse \"%s\" as an "
1519 "IPv6 address", sender_host_address);
1520 #if HAVE_GETIPNODEBYADDR
1521 hosts = getipnodebyaddr(CS &addr6, sizeof(addr6), AF_INET6, &h_errno);
1522 #else
1523 hosts = gethostbyaddr(CS &addr6, sizeof(addr6), AF_INET6);
1524 #endif
1525 }
1526else
1527 {
1528 if (inet_pton(AF_INET, CS sender_host_address, &addr) != 1)
1529 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "unable to parse \"%s\" as an "
1530 "IPv4 address", sender_host_address);
1531 #if HAVE_GETIPNODEBYADDR
1532 hosts = getipnodebyaddr(CS &addr, sizeof(addr), AF_INET, &h_errno);
1533 #else
1534 hosts = gethostbyaddr(CS &addr, sizeof(addr), AF_INET);
1535 #endif
1536 }
1537
1538/* Do lookup on IPv4 system */
1539
1540#else
1541addr.s_addr = (S_ADDR_TYPE)inet_addr(CS sender_host_address);
1542hosts = gethostbyaddr(CS(&addr), sizeof(addr), AF_INET);
1543#endif
1544
846430d9
JH
1545if ( slow_lookup_log
1546 && (time_msec = get_time_in_ms() - time_msec) > slow_lookup_log
1547 )
30795c5e 1548 log_long_lookup(US"gethostbyaddr", sender_host_address, time_msec);
846430d9 1549
059ec3d9
PH
1550/* Failed to look up the host. */
1551
f3ebb786 1552if (!hosts)
059ec3d9
PH
1553 {
1554 HDEBUG(D_host_lookup) debug_printf("IP address lookup failed: h_errno=%d\n",
1555 h_errno);
1556 return (h_errno == TRY_AGAIN || h_errno == NO_RECOVERY) ? DEFER : FAIL;
1557 }
1558
1559/* It seems there are some records in the DNS that yield an empty name. We
1560treat this as non-existent. In some operating systems, this is returned as an
1561empty string; in others as a single dot. */
1562
f3ebb786 1563if (!hosts->h_name || !hosts->h_name[0] || hosts->h_name[0] == '.')
059ec3d9
PH
1564 {
1565 HDEBUG(D_host_lookup) debug_printf("IP address lookup yielded an empty name: "
1566 "treated as non-existent host name\n");
1567 return FAIL;
1568 }
1569
1570/* Copy and lowercase the name, which is in static storage in many systems.
1571Put it in permanent memory. */
1572
f3ebb786
JH
1573 {
1574 int old_pool = store_pool;
1575 store_pool = POOL_TAINT_PERM; /* names are tainted */
059ec3d9 1576
f3ebb786 1577 sender_host_name = string_copylc(US hosts->h_name);
059ec3d9 1578
f3ebb786
JH
1579 /* If the host has aliases, build a copy of the alias list */
1580
1581 if (hosts->h_aliases)
059ec3d9 1582 {
f3ebb786
JH
1583 int count = 1;
1584 uschar **ptr;
1585
1586 for (uschar ** aliases = USS hosts->h_aliases; *aliases; aliases++) count++;
1587 store_pool = POOL_PERM;
1588 ptr = sender_host_aliases = store_get(count * sizeof(uschar *), FALSE);
1589 store_pool = POOL_TAINT_PERM;
1590
1591 for (uschar ** aliases = USS hosts->h_aliases; *aliases; aliases++)
1592 *ptr++ = string_copylc(*aliases);
1593 *ptr = NULL;
059ec3d9 1594 }
f3ebb786 1595 store_pool = old_pool;
059ec3d9
PH
1596 }
1597
1598return OK;
1599}
1600
1601
1602
1603/*************************************************
1604* Find host name for incoming call *
1605*************************************************/
1606
1607/* Put the name in permanent store, pointed to by sender_host_name. We also set
1608up a list of alias names, pointed to by sender_host_alias. The list is
1609NULL-terminated. The incoming address is in sender_host_address, either in
1610dotted-quad form for IPv4 or in colon-separated form for IPv6.
1611
1612This function does a thorough check that the names it finds point back to the
1613incoming IP address. Any that do not are discarded. Note that this is relied on
1614by the ACL reverse_host_lookup check.
1615
1616On some systems, get{host,ipnode}byaddr() appears to do this internally, but
1617this it not universally true. Also, for release 4.30, this function was changed
1618to do a direct DNS lookup first, by default[1], because it turns out that that
1619is the only guaranteed way to find all the aliases on some systems. My
1620experiments indicate that Solaris gethostbyaddr() gives the aliases for but
1621Linux does not.
1622
1623[1] The actual order is controlled by the host_lookup_order option.
1624
1625Arguments: none
1626Returns: OK on success, the answer being placed in the global variable
1627 sender_host_name, with any aliases in a list hung off
1628 sender_host_aliases
1629 FAIL if no host name can be found
1630 DEFER if a temporary error was encountered
1631
4c04137d 1632The variable host_lookup_msg is set to an empty string on success, or to a
059ec3d9 1633reason for the failure otherwise, in a form suitable for tagging onto an error
8e669ac1 1634message, and also host_lookup_failed is set TRUE if the lookup failed. If there
b08b24c8
PH
1635was a defer, host_lookup_deferred is set TRUE.
1636
1637Any dynamically constructed string for host_lookup_msg must be in permanent
1638store, because it might be used for several incoming messages on the same SMTP
059ec3d9
PH
1639connection. */
1640
1641int
1642host_name_lookup(void)
1643{
1644int old_pool, rc;
1645int sep = 0;
d7978c0f 1646uschar *save_hostname;
059ec3d9 1647uschar **aliases;
059ec3d9 1648uschar *ordername;
55414b25 1649const uschar *list = host_lookup_order;
8743d3ac 1650dns_answer * dnsa = store_get_dns_answer();
059ec3d9
PH
1651dns_scan dnss;
1652
1f4a55da 1653sender_host_dnssec = host_lookup_deferred = host_lookup_failed = FALSE;
b08b24c8 1654
059ec3d9
PH
1655HDEBUG(D_host_lookup)
1656 debug_printf("looking up host name for %s\n", sender_host_address);
1657
1658/* For testing the case when a lookup does not complete, we have a special
1659reserved IP address. */
1660
8768d548 1661if (f.running_in_test_harness &&
059ec3d9
PH
1662 Ustrcmp(sender_host_address, "99.99.99.99") == 0)
1663 {
1664 HDEBUG(D_host_lookup)
1665 debug_printf("Test harness: host name lookup returns DEFER\n");
8e669ac1 1666 host_lookup_deferred = TRUE;
059ec3d9
PH
1667 return DEFER;
1668 }
1669
1670/* Do lookups directly in the DNS or via gethostbyaddr() (or equivalent), in
1671the order specified by the host_lookup_order option. */
1672
152481a0 1673while ((ordername = string_nextinlist(&list, &sep, NULL, 0)))
059ec3d9
PH
1674 {
1675 if (strcmpic(ordername, US"bydns") == 0)
1676 {
152481a0
JH
1677 uschar * name = dns_build_reverse(sender_host_address);
1678
9d9c3746 1679 dns_init(FALSE, FALSE, FALSE); /* dnssec ctrl by dns_dnssec_ok glbl */
152481a0 1680 rc = dns_lookup_timerwrap(dnsa, name, T_PTR, NULL);
059ec3d9
PH
1681
1682 /* The first record we come across is used for the name; others are
1683 considered to be aliases. We have to scan twice, in order to find out the
1684 number of aliases. However, if all the names are empty, we will behave as
1685 if failure. (PTR records that yield empty names have been encountered in
1686 the DNS.) */
1687
1688 if (rc == DNS_SUCCEED)
1689 {
1690 uschar **aptr = NULL;
1691 int ssize = 264;
1692 int count = 0;
1693 int old_pool = store_pool;
1694
8743d3ac 1695 sender_host_dnssec = dns_is_secure(dnsa);
1f4a55da
PP
1696 DEBUG(D_dns)
1697 debug_printf("Reverse DNS security status: %s\n",
1698 sender_host_dnssec ? "DNSSEC verified (AD)" : "unverified");
1699
059ec3d9
PH
1700 store_pool = POOL_PERM; /* Save names in permanent storage */
1701
8743d3ac 1702 for (dns_record * rr = dns_next_rr(dnsa, &dnss, RESET_ANSWERS);
1705dd20 1703 rr;
8743d3ac 1704 rr = dns_next_rr(dnsa, &dnss, RESET_NEXT)) if (rr->type == T_PTR)
d7978c0f 1705 count++;
059ec3d9
PH
1706
1707 /* Get store for the list of aliases. For compatibility with
1708 gethostbyaddr, we make an empty list if there are none. */
1709
f3ebb786 1710 aptr = sender_host_aliases = store_get(count * sizeof(uschar *), FALSE);
059ec3d9
PH
1711
1712 /* Re-scan and extract the names */
1713
8743d3ac 1714 for (dns_record * rr = dns_next_rr(dnsa, &dnss, RESET_ANSWERS);
1705dd20 1715 rr;
8743d3ac 1716 rr = dns_next_rr(dnsa, &dnss, RESET_NEXT)) if (rr->type == T_PTR)
059ec3d9 1717 {
f3ebb786 1718 uschar * s = store_get(ssize, TRUE); /* names are tainted */
059ec3d9
PH
1719
1720 /* If an overlong response was received, the data will have been
1721 truncated and dn_expand may fail. */
1722
8743d3ac 1723 if (dn_expand(dnsa->answer, dnsa->answer + dnsa->answerlen,
5903c6ff 1724 US (rr->data), (DN_EXPAND_ARG4_TYPE)(s), ssize) < 0)
059ec3d9
PH
1725 {
1726 log_write(0, LOG_MAIN, "host name alias list truncated for %s",
1727 sender_host_address);
1728 break;
1729 }
1730
f3ebb786
JH
1731 store_release_above(s + Ustrlen(s) + 1);
1732 if (!s[0])
059ec3d9
PH
1733 {
1734 HDEBUG(D_host_lookup) debug_printf("IP address lookup yielded an "
1735 "empty name: treated as non-existent host name\n");
1736 continue;
1737 }
1f155f8e
JH
1738 if (!sender_host_name) sender_host_name = s;
1739 else *aptr++ = s;
f3ebb786 1740 while (*s) { *s = tolower(*s); s++; }
059ec3d9
PH
1741 }
1742
1743 *aptr = NULL; /* End of alias list */
1744 store_pool = old_pool; /* Reset store pool */
1745
f3ebb786 1746 /* If we've found a name, break out of the "order" loop */
059ec3d9 1747
f3ebb786 1748 if (sender_host_name) break;
059ec3d9
PH
1749 }
1750
1751 /* If the DNS lookup deferred, we must also defer. */
1752
1753 if (rc == DNS_AGAIN)
1754 {
1755 HDEBUG(D_host_lookup)
1756 debug_printf("IP address PTR lookup gave temporary error\n");
8e669ac1 1757 host_lookup_deferred = TRUE;
059ec3d9
PH
1758 return DEFER;
1759 }
1760 }
1761
1762 /* Do a lookup using gethostbyaddr() - or equivalent */
1763
1764 else if (strcmpic(ordername, US"byaddr") == 0)
1765 {
1766 HDEBUG(D_host_lookup)
1767 debug_printf("IP address lookup using gethostbyaddr()\n");
059ec3d9 1768 rc = host_name_lookup_byaddr();
8e669ac1 1769 if (rc == DEFER)
b08b24c8 1770 {
8e669ac1 1771 host_lookup_deferred = TRUE;
b08b24c8 1772 return rc; /* Can't carry on */
8e669ac1 1773 }
059ec3d9
PH
1774 if (rc == OK) break; /* Found a name */
1775 }
1776 } /* Loop for bydns/byaddr scanning */
1777
1778/* If we have failed to find a name, return FAIL and log when required.
1779NB host_lookup_msg must be in permanent store. */
1780
94759fce 1781if (!sender_host_name)
059ec3d9 1782 {
8768d548 1783 if (host_checking || !f.log_testing_mode)
059ec3d9
PH
1784 log_write(L_host_lookup_failed, LOG_MAIN, "no host name found for IP "
1785 "address %s", sender_host_address);
1786 host_lookup_msg = US" (failed to find host name from IP address)";
b08b24c8 1787 host_lookup_failed = TRUE;
059ec3d9
PH
1788 return FAIL;
1789 }
1790
059ec3d9
PH
1791HDEBUG(D_host_lookup)
1792 {
1793 uschar **aliases = sender_host_aliases;
de11307f
JH
1794 debug_printf("IP address lookup yielded \"%s\"\n", sender_host_name);
1795 while (*aliases != NULL) debug_printf(" alias \"%s\"\n", *aliases++);
059ec3d9
PH
1796 }
1797
1798/* We need to verify that a forward lookup on the name we found does indeed
1799correspond to the address. This is for security: in principle a malefactor who
1800happened to own a reverse zone could set it to point to any names at all.
1801
1802This code was present in versions of Exim before 3.20. At that point I took it
1803out because I thought that gethostbyaddr() did the check anyway. It turns out
1804that this isn't always the case, so it's coming back in at 4.01. This version
1805is actually better, because it also checks aliases.
1806
1807The code was made more robust at release 4.21. Prior to that, it accepted all
1808the names if any of them had the correct IP address. Now the code checks all
1809the names, and accepts only those that have the correct IP address. */
1810
1811save_hostname = sender_host_name; /* Save for error messages */
1812aliases = sender_host_aliases;
d7978c0f 1813for (uschar * hname = sender_host_name; hname; hname = *aliases++)
059ec3d9
PH
1814 {
1815 int rc;
1816 BOOL ok = FALSE;
94759fce
JH
1817 host_item h = { .next = NULL, .name = hname, .mx = MX_NONE, .address = NULL };
1818 dnssec_domains d =
1819 { .request = sender_host_dnssec ? US"*" : NULL, .require = NULL };
059ec3d9 1820
66387a73 1821 if ( (rc = host_find_bydns(&h, NULL, HOST_FIND_BY_A | HOST_FIND_BY_AAAA,
1f155f8e
JH
1822 NULL, NULL, NULL, &d, NULL, NULL)) == HOST_FOUND
1823 || rc == HOST_FOUND_LOCAL
1824 )
059ec3d9 1825 {
059ec3d9 1826 HDEBUG(D_host_lookup) debug_printf("checking addresses for %s\n", hname);
1f155f8e
JH
1827
1828 /* If the forward lookup was not secure we cancel the is-secure variable */
1829
1830 DEBUG(D_dns) debug_printf("Forward DNS security status: %s\n",
1831 h.dnssec == DS_YES ? "DNSSEC verified (AD)" : "unverified");
1832 if (h.dnssec != DS_YES) sender_host_dnssec = FALSE;
1833
d7978c0f 1834 for (host_item * hh = &h; hh; hh = hh->next)
d27f1df3 1835 if (host_is_in_net(hh->address, sender_host_address, 0))
059ec3d9
PH
1836 {
1837 HDEBUG(D_host_lookup) debug_printf(" %s OK\n", hh->address);
1838 ok = TRUE;
1839 break;
1840 }
1841 else
059ec3d9 1842 HDEBUG(D_host_lookup) debug_printf(" %s\n", hh->address);
1f155f8e 1843
059ec3d9
PH
1844 if (!ok) HDEBUG(D_host_lookup)
1845 debug_printf("no IP address for %s matched %s\n", hname,
1846 sender_host_address);
1847 }
1848 else if (rc == HOST_FIND_AGAIN)
1849 {
1850 HDEBUG(D_host_lookup) debug_printf("temporary error for host name lookup\n");
8e669ac1 1851 host_lookup_deferred = TRUE;
55728a4f 1852 sender_host_name = NULL;
059ec3d9
PH
1853 return DEFER;
1854 }
1855 else
059ec3d9 1856 HDEBUG(D_host_lookup) debug_printf("no IP addresses found for %s\n", hname);
059ec3d9
PH
1857
1858 /* If this name is no good, and it's the sender name, set it null pro tem;
1859 if it's an alias, just remove it from the list. */
1860
1861 if (!ok)
1862 {
1863 if (hname == sender_host_name) sender_host_name = NULL; else
1864 {
1865 uschar **a; /* Don't amalgamate - some */
1866 a = --aliases; /* compilers grumble */
1867 while (*a != NULL) { *a = a[1]; a++; }
1868 }
1869 }
1870 }
1871
1872/* If sender_host_name == NULL, it means we didn't like the name. Replace
1873it with the first alias, if there is one. */
1874
1875if (sender_host_name == NULL && *sender_host_aliases != NULL)
1876 sender_host_name = *sender_host_aliases++;
1877
1878/* If we now have a main name, all is well. */
1879
1880if (sender_host_name != NULL) return OK;
1881
1882/* We have failed to find an address that matches. */
1883
1884HDEBUG(D_host_lookup)
1885 debug_printf("%s does not match any IP address for %s\n",
1886 sender_host_address, save_hostname);
1887
1888/* This message must be in permanent store */
1889
1890old_pool = store_pool;
1891store_pool = POOL_PERM;
1892host_lookup_msg = string_sprintf(" (%s does not match any IP address for %s)",
1893 sender_host_address, save_hostname);
1894store_pool = old_pool;
059ec3d9
PH
1895host_lookup_failed = TRUE;
1896return FAIL;
1897}
1898
1899
1900
1901
1902/*************************************************
1903* Find IP address(es) for host by name *
1904*************************************************/
1905
1906/* The input is a host_item structure with the name filled in and the address
322050c2
PH
1907field set to NULL. We use gethostbyname() or getipnodebyname() or
1908gethostbyname2(), as appropriate. Of course, these functions may use the DNS,
1909but they do not do MX processing. It appears, however, that in some systems the
1910current setting of resolver options is used when one of these functions calls
1911the resolver. For this reason, we call dns_init() at the start, with arguments
1912influenced by bits in "flags", just as we do for host_find_bydns().
059ec3d9
PH
1913
1914The second argument provides a host list (usually an IP list) of hosts to
1915ignore. This makes it possible to ignore IPv6 link-local addresses or loopback
1916addresses in unreasonable places.
1917
1918The lookup may result in a change of name. For compatibility with the dns
1919lookup, return this via fully_qualified_name as well as updating the host item.
1920The lookup may also yield more than one IP address, in which case chain on
1921subsequent host_item structures.
1922
1923Arguments:
1924 host a host item with the name and MX filled in;
1925 the address is to be filled in;
1926 multiple IP addresses cause other host items to be
1927 chained on.
1928 ignore_target_hosts a list of hosts to ignore
322050c2
PH
1929 flags HOST_FIND_QUALIFY_SINGLE ) passed to
1930 HOST_FIND_SEARCH_PARENTS ) dns_init()
059ec3d9
PH
1931 fully_qualified_name if not NULL, set to point to host name for
1932 compatibility with host_find_bydns
1933 local_host_check TRUE if a check for the local host is wanted
1934
1935Returns: HOST_FIND_FAILED Failed to find the host or domain
1936 HOST_FIND_AGAIN Try again later
1937 HOST_FOUND Host found - data filled in
1938 HOST_FOUND_LOCAL Host found and is the local host
1939*/
1940
1941int
55414b25
JH
1942host_find_byname(host_item *host, const uschar *ignore_target_hosts, int flags,
1943 const uschar **fully_qualified_name, BOOL local_host_check)
059ec3d9 1944{
d7978c0f 1945int yield, times;
059ec3d9
PH
1946host_item *last = NULL;
1947BOOL temp_error = FALSE;
b08b24c8
PH
1948#if HAVE_IPV6
1949int af;
1950#endif
1951
322050c2
PH
1952/* Make sure DNS options are set as required. This appears to be necessary in
1953some circumstances when the get..byname() function actually calls the DNS. */
1954
1955dns_init((flags & HOST_FIND_QUALIFY_SINGLE) != 0,
8c51eead 1956 (flags & HOST_FIND_SEARCH_PARENTS) != 0,
7cd171b7 1957 FALSE); /* Cannot retrieve dnssec status so do not request */
322050c2 1958
7e66e54d
PH
1959/* In an IPv6 world, unless IPv6 has been disabled, we need to scan for both
1960kinds of address, so go round the loop twice. Note that we have ensured that
1961AF_INET6 is defined even in an IPv4 world, which makes for slightly tidier
1962code. However, if dns_ipv4_lookup matches the domain, we also just do IPv4
1963lookups here (except when testing standalone). */
059ec3d9
PH
1964
1965#if HAVE_IPV6
322050c2
PH
1966 #ifdef STAND_ALONE
1967 if (disable_ipv6)
1968 #else
1969 if (disable_ipv6 ||
1970 (dns_ipv4_lookup != NULL &&
55414b25
JH
1971 match_isinlist(host->name, CUSS &dns_ipv4_lookup, 0, NULL, NULL,
1972 MCL_DOMAIN, TRUE, NULL) == OK))
322050c2
PH
1973 #endif
1974
059ec3d9
PH
1975 { af = AF_INET; times = 1; }
1976 else
059ec3d9
PH
1977 { af = AF_INET6; times = 2; }
1978
1979/* No IPv6 support */
1980
1981#else /* HAVE_IPV6 */
1982 times = 1;
1983#endif /* HAVE_IPV6 */
1984
1985/* Initialize the flag that gets set for DNS syntax check errors, so that the
1986interface to this function can be similar to host_find_bydns. */
1987
8768d548 1988f.host_find_failed_syntax = FALSE;
059ec3d9
PH
1989
1990/* Loop to look up both kinds of address in an IPv6 world */
1991
d7978c0f 1992for (int i = 1; i <= times;
059ec3d9
PH
1993 #if HAVE_IPV6
1994 af = AF_INET, /* If 2 passes, IPv4 on the second */
1995 #endif
1996 i++)
1997 {
1998 BOOL ipv4_addr;
91ecef39 1999 int error_num = 0;
059ec3d9 2000 struct hostent *hostdata;
0539a19d 2001 unsigned long time_msec = 0; /* compiler quietening */
059ec3d9 2002
322050c2
PH
2003 #ifdef STAND_ALONE
2004 printf("Looking up: %s\n", host->name);
2005 #endif
2006
846430d9
JH
2007 if (slow_lookup_log) time_msec = get_time_in_ms();
2008
059ec3d9 2009 #if HAVE_IPV6
8768d548 2010 if (f.running_in_test_harness)
e7726cbf
PH
2011 hostdata = host_fake_gethostbyname(host->name, af, &error_num);
2012 else
2013 {
059ec3d9
PH
2014 #if HAVE_GETIPNODEBYNAME
2015 hostdata = getipnodebyname(CS host->name, af, 0, &error_num);
2016 #else
2017 hostdata = gethostbyname2(CS host->name, af);
2018 error_num = h_errno;
2019 #endif
e7726cbf
PH
2020 }
2021
2022 #else /* not HAVE_IPV6 */
8768d548 2023 if (f.running_in_test_harness)
e7726cbf
PH
2024 hostdata = host_fake_gethostbyname(host->name, AF_INET, &error_num);
2025 else
2026 {
2027 hostdata = gethostbyname(CS host->name);
2028 error_num = h_errno;
2029 }
2030 #endif /* HAVE_IPV6 */
059ec3d9 2031
0539a19d 2032 if ( slow_lookup_log
abe1353e 2033 && (time_msec = get_time_in_ms() - time_msec) > slow_lookup_log)
30795c5e 2034 log_long_lookup(US"gethostbyname", host->name, time_msec);
846430d9 2035
accf9211 2036 if (!hostdata)
059ec3d9
PH
2037 {
2038 uschar *error;
2039 switch (error_num)
2040 {
2041 case HOST_NOT_FOUND: error = US"HOST_NOT_FOUND"; break;
4a452c43
JH
2042 case TRY_AGAIN: error = US"TRY_AGAIN"; break;
2043 case NO_RECOVERY: error = US"NO_RECOVERY"; break;
2044 case NO_DATA: error = US"NO_DATA"; break;
accf9211 2045 #if NO_DATA != NO_ADDRESS
4a452c43 2046 case NO_ADDRESS: error = US"NO_ADDRESS"; break;
accf9211 2047 #endif
059ec3d9
PH
2048 default: error = US"?"; break;
2049 }
2050
2051 DEBUG(D_host_lookup) debug_printf("%s returned %d (%s)\n",
accf9211 2052 f.running_in_test_harness ? "host_fake_gethostbyname" :
059ec3d9
PH
2053 #if HAVE_IPV6
2054 #if HAVE_GETIPNODEBYNAME
accf9211 2055 af == AF_INET6 ? "getipnodebyname(af=inet6)" : "getipnodebyname(af=inet)",
059ec3d9 2056 #else
accf9211 2057 af == AF_INET6 ? "gethostbyname2(af=inet6)" : "gethostbyname2(af=inet)",
059ec3d9
PH
2058 #endif
2059 #else
2060 "gethostbyname",
2061 #endif
2062 error_num, error);
2063
2064 if (error_num == TRY_AGAIN || error_num == NO_RECOVERY) temp_error = TRUE;
2065 continue;
2066 }
2067 if ((hostdata->h_addr_list)[0] == NULL) continue;
2068
2069 /* Replace the name with the fully qualified one if necessary, and fill in
2070 the fully_qualified_name pointer. */
2071
2072 if (hostdata->h_name[0] != 0 &&
2073 Ustrcmp(host->name, hostdata->h_name) != 0)
5903c6ff 2074 host->name = string_copy_dnsdomain(US hostdata->h_name);
059ec3d9
PH
2075 if (fully_qualified_name != NULL) *fully_qualified_name = host->name;
2076
2077 /* Get the list of addresses. IPv4 and IPv6 addresses can be distinguished
2078 by their different lengths. Scan the list, ignoring any that are to be
2079 ignored, and build a chain from the rest. */
2080
2081 ipv4_addr = hostdata->h_length == sizeof(struct in_addr);
2082
d7978c0f 2083 for (uschar ** addrlist = USS hostdata->h_addr_list; *addrlist; addrlist++)
059ec3d9
PH
2084 {
2085 uschar *text_address =
2086 host_ntoa(ipv4_addr? AF_INET:AF_INET6, *addrlist, NULL, NULL);
2087
2088 #ifndef STAND_ALONE
2089 if (ignore_target_hosts != NULL &&
2090 verify_check_this_host(&ignore_target_hosts, NULL, host->name,
2091 text_address, NULL) == OK)
2092 {
2093 DEBUG(D_host_lookup)
2094 debug_printf("ignored host %s [%s]\n", host->name, text_address);
2095 continue;
2096 }
2097 #endif
2098
2099 /* If this is the first address, last == NULL and we put the data in the
2100 original block. */
2101
2102 if (last == NULL)
2103 {
2104 host->address = text_address;
2105 host->port = PORT_NONE;
2106 host->status = hstatus_unknown;
2107 host->why = hwhy_unknown;
783b385f 2108 host->dnssec = DS_UNK;
059ec3d9
PH
2109 last = host;
2110 }
2111
2112 /* Else add further host item blocks for any other addresses, keeping
2113 the order. */
2114
2115 else
2116 {
f3ebb786 2117 host_item *next = store_get(sizeof(host_item), FALSE);
059ec3d9
PH
2118 next->name = host->name;
2119 next->mx = host->mx;
2120 next->address = text_address;
2121 next->port = PORT_NONE;
2122 next->status = hstatus_unknown;
2123 next->why = hwhy_unknown;
783b385f 2124 next->dnssec = DS_UNK;
059ec3d9
PH
2125 next->last_try = 0;
2126 next->next = last->next;
2127 last->next = next;
2128 last = next;
2129 }
2130 }
2131 }
2132
2133/* If no hosts were found, the address field in the original host block will be
2134NULL. If temp_error is set, at least one of the lookups gave a temporary error,
2135so we pass that back. */
2136
2137if (host->address == NULL)
2138 {
2139 uschar *msg =
2140 #ifndef STAND_ALONE
2141 (message_id[0] == 0 && smtp_in != NULL)?
2142 string_sprintf("no IP address found for host %s (during %s)", host->name,
2143 smtp_get_connection_info()) :
2144 #endif
2145 string_sprintf("no IP address found for host %s", host->name);
2146
2147 HDEBUG(D_host_lookup) debug_printf("%s\n", msg);
9b8fadde 2148 if (temp_error) goto RETURN_AGAIN;
8768d548 2149 if (host_checking || !f.log_testing_mode)
059ec3d9
PH
2150 log_write(L_host_lookup_failed, LOG_MAIN, "%s", msg);
2151 return HOST_FIND_FAILED;
2152 }
2153
2154/* Remove any duplicate IP addresses, then check to see if this is the local
2155host if required. */
2156
2157host_remove_duplicates(host, &last);
2158yield = local_host_check?
2159 host_scan_for_local_hosts(host, &last, NULL) : HOST_FOUND;
2160
059ec3d9
PH
2161HDEBUG(D_host_lookup)
2162 {
d7978c0f 2163 if (fully_qualified_name)
059ec3d9
PH
2164 debug_printf("fully qualified name = %s\n", *fully_qualified_name);
2165 debug_printf("%s looked up these IP addresses:\n",
2166 #if HAVE_IPV6
2167 #if HAVE_GETIPNODEBYNAME
2168 "getipnodebyname"
2169 #else
2170 "gethostbyname2"
2171 #endif
2172 #else
2173 "gethostbyname"
2174 #endif
2175 );
d7978c0f 2176 for (const host_item * h = host; h != last->next; h = h->next)
059ec3d9 2177 debug_printf(" name=%s address=%s\n", h->name,
d7978c0f 2178 h->address ? h->address : US"<null>");
059ec3d9
PH
2179 }
2180
2181/* Return the found status. */
2182
2183return yield;
9b8fadde
PH
2184
2185/* Handle the case when there is a temporary error. If the name matches
2186dns_again_means_nonexist, return permanent rather than temporary failure. */
2187
2188RETURN_AGAIN:
2189 {
2190 #ifndef STAND_ALONE
2191 int rc;
55414b25 2192 const uschar *save = deliver_domain;
9b8fadde 2193 deliver_domain = host->name; /* set $domain */
55414b25 2194 rc = match_isinlist(host->name, CUSS &dns_again_means_nonexist, 0, NULL, NULL,
9b8fadde
PH
2195 MCL_DOMAIN, TRUE, NULL);
2196 deliver_domain = save;
2197 if (rc == OK)
2198 {
2199 DEBUG(D_host_lookup) debug_printf("%s is in dns_again_means_nonexist: "
2200 "returning HOST_FIND_FAILED\n", host->name);
2201 return HOST_FIND_FAILED;
2202 }
2203 #endif
2204 return HOST_FIND_AGAIN;
2205 }
059ec3d9
PH
2206}
2207
2208
2209
2210/*************************************************
2211* Fill in a host address from the DNS *
2212*************************************************/
2213
1349e1e5
PH
2214/* Given a host item, with its name, port and mx fields set, and its address
2215field set to NULL, fill in its IP address from the DNS. If it is multi-homed,
2216create additional host items for the additional addresses, copying all the
2217other fields, and randomizing the order.
059ec3d9 2218
66387a73 2219On IPv6 systems, AAAA records are sought first, then A records.
059ec3d9
PH
2220
2221The host name may be changed if the DNS returns a different name - e.g. fully
2222qualified or changed via CNAME. If fully_qualified_name is not NULL, dns_lookup
2223ensures that it points to the fully qualified name. However, this is the fully
2224qualified version of the original name; if a CNAME is involved, the actual
2225canonical host name may be different again, and so we get it directly from the
2226relevant RR. Note that we do NOT change the mx field of the host item in this
2227function as it may be called to set the addresses of hosts taken from MX
2228records.
2229
2230Arguments:
2231 host points to the host item we're filling in
2232 lastptr points to pointer to last host item in a chain of
2233 host items (may be updated if host is last and gets
2234 extended because multihomed)
2235 ignore_target_hosts list of hosts to ignore
2236 allow_ip if TRUE, recognize an IP address and return it
2237 fully_qualified_name if not NULL, return fully qualified name here if
2238 the contents are different (i.e. it must be preset
2239 to something)
221dff13
HSHR
2240 dnssec_request if TRUE request the AD bit
2241 dnssec_require if TRUE require the AD bit
66387a73 2242 whichrrs select ipv4, ipv6 results
059ec3d9
PH
2243
2244Returns: HOST_FIND_FAILED couldn't find A record
2245 HOST_FIND_AGAIN try again later
2546388c 2246 HOST_FIND_SECURITY dnssec required but not acheived
059ec3d9
PH
2247 HOST_FOUND found AAAA and/or A record(s)
2248 HOST_IGNORED found, but all IPs ignored
2249*/
2250
2251static int
2252set_address_from_dns(host_item *host, host_item **lastptr,
55414b25
JH
2253 const uschar *ignore_target_hosts, BOOL allow_ip,
2254 const uschar **fully_qualified_name,
66387a73 2255 BOOL dnssec_request, BOOL dnssec_require, int whichrrs)
059ec3d9 2256{
059ec3d9
PH
2257host_item *thishostlast = NULL; /* Indicates not yet filled in anything */
2258BOOL v6_find_again = FALSE;
2546388c 2259BOOL dnssec_fail = FALSE;
059ec3d9
PH
2260int i;
2261
2262/* If allow_ip is set, a name which is an IP address returns that value
2263as its address. This is used for MX records when allow_mx_to_ip is set, for
2264those sites that feel they have to flaunt the RFC rules. */
2265
2266if (allow_ip && string_is_ip_address(host->name, NULL) != 0)
2267 {
2268 #ifndef STAND_ALONE
66387a73
JH
2269 if ( ignore_target_hosts
2270 && verify_check_this_host(&ignore_target_hosts, NULL, host->name,
059ec3d9
PH
2271 host->name, NULL) == OK)
2272 return HOST_IGNORED;
2273 #endif
2274
2275 host->address = host->name;
059ec3d9
PH
2276 return HOST_FOUND;
2277 }
2278
0539a19d 2279/* On an IPv6 system, unless IPv6 is disabled, go round the loop up to twice,
66387a73
JH
2280looking for AAAA records the first time. However, unless doing standalone
2281testing, we force an IPv4 lookup if the domain matches dns_ipv4_lookup global.
2282On an IPv4 system, go round the loop once only, looking only for A records. */
059ec3d9
PH
2283
2284#if HAVE_IPV6
059ec3d9 2285 #ifndef STAND_ALONE
66387a73
JH
2286 if ( disable_ipv6
2287 || !(whichrrs & HOST_FIND_BY_AAAA)
2288 || (dns_ipv4_lookup
2289 && match_isinlist(host->name, CUSS &dns_ipv4_lookup, 0, NULL, NULL,
2290 MCL_DOMAIN, TRUE, NULL) == OK)
2291 )
059ec3d9
PH
2292 i = 0; /* look up A records only */
2293 else
2294 #endif /* STAND_ALONE */
2295
059ec3d9 2296 i = 1; /* look up AAAA and A records */
059ec3d9
PH
2297
2298/* The IPv4 world */
2299
2300#else /* HAVE_IPV6 */
2301 i = 0; /* look up A records only */
2302#endif /* HAVE_IPV6 */
2303
2304for (; i >= 0; i--)
2305 {
0539a19d 2306 static int types[] = { T_A, T_AAAA };
059ec3d9 2307 int type = types[i];
66387a73
JH
2308 int randoffset = i == (whichrrs & HOST_FIND_IPV4_FIRST ? 1 : 0)
2309 ? 500 : 0; /* Ensures v6/4 sort order */
8743d3ac 2310 dns_answer * dnsa = store_get_dns_answer();
059ec3d9
PH
2311 dns_scan dnss;
2312
8743d3ac 2313 int rc = dns_lookup_timerwrap(dnsa, host->name, type, fully_qualified_name);
cf2b569e 2314 lookup_dnssec_authenticated = !dnssec_request ? NULL
8743d3ac 2315 : dns_is_secure(dnsa) ? US"yes" : US"no";
059ec3d9 2316
221dff13 2317 DEBUG(D_dns)
0539a19d 2318 if ( (dnssec_request || dnssec_require)
8743d3ac
JH
2319 && !dns_is_secure(dnsa)
2320 && dns_is_aa(dnsa)
0539a19d
JH
2321 )
2322 debug_printf("DNS lookup of %.256s (A/AAAA) requested AD, but got AA\n", host->name);
221dff13 2323
0539a19d 2324 /* We want to return HOST_FIND_AGAIN if one of the A or AAAA lookups
059ec3d9
PH
2325 fails or times out, but not if another one succeeds. (In the early
2326 IPv6 days there are name servers that always fail on AAAA, but are happy
2327 to give out an A record. We want to proceed with that A record.) */
8e669ac1 2328
059ec3d9
PH
2329 if (rc != DNS_SUCCEED)
2330 {
2331 if (i == 0) /* Just tried for an A record, i.e. end of loop */
2332 {
0539a19d 2333 if (host->address != NULL) return HOST_FOUND; /* AAAA was found */
059ec3d9
PH
2334 if (rc == DNS_AGAIN || rc == DNS_FAIL || v6_find_again)
2335 return HOST_FIND_AGAIN;
2336 return HOST_FIND_FAILED; /* DNS_NOMATCH or DNS_NODATA */
2337 }
2338
0539a19d 2339 /* Tried for an AAAA record: remember if this was a temporary
059ec3d9
PH
2340 error, and look for the next record type. */
2341
2342 if (rc != DNS_NOMATCH && rc != DNS_NODATA) v6_find_again = TRUE;
2343 continue;
2344 }
cf2b569e
JH
2345
2346 if (dnssec_request)
8c51eead 2347 {
8743d3ac 2348 if (dns_is_secure(dnsa))
cf2b569e
JH
2349 {
2350 DEBUG(D_host_lookup) debug_printf("%s A DNSSEC\n", host->name);
2351 if (host->dnssec == DS_UNK) /* set in host_find_bydns() */
2352 host->dnssec = DS_YES;
2353 }
2354 else
2355 {
2356 if (dnssec_require)
2357 {
2546388c
JH
2358 dnssec_fail = TRUE;
2359 DEBUG(D_host_lookup) debug_printf("dnssec fail on %s for %.256s",
0539a19d 2360 i>0 ? "AAAA" : "A", host->name);
cf2b569e
JH
2361 continue;
2362 }
2363 if (host->dnssec == DS_YES) /* set in host_find_bydns() */
2364 {
2365 DEBUG(D_host_lookup) debug_printf("%s A cancel DNSSEC\n", host->name);
2366 host->dnssec = DS_NO;
2367 lookup_dnssec_authenticated = US"no";
2368 }
2369 }
8c51eead 2370 }
059ec3d9
PH
2371
2372 /* Lookup succeeded: fill in the given host item with the first non-ignored
2373 address found; create additional items for any others. A single A6 record
8241d8dd
JH
2374 may generate more than one address. The lookup had a chance to update the
2375 fqdn; we do not want any later times round the loop to do so. */
2376
2377 fully_qualified_name = NULL;
059ec3d9 2378
8743d3ac 2379 for (dns_record * rr = dns_next_rr(dnsa, &dnss, RESET_ANSWERS);
e1a3f32f 2380 rr;
8743d3ac 2381 rr = dns_next_rr(dnsa, &dnss, RESET_NEXT)) if (rr->type == type)
059ec3d9 2382 {
8743d3ac 2383 dns_address * da = dns_address_from_rr(dnsa, rr);
059ec3d9 2384
d7978c0f
JH
2385 DEBUG(D_host_lookup)
2386 if (!da) debug_printf("no addresses extracted from A6 RR for %s\n",
2387 host->name);
059ec3d9 2388
d7978c0f
JH
2389 /* This loop runs only once for A and AAAA records, but may run
2390 several times for an A6 record that generated multiple addresses. */
059ec3d9 2391
d7978c0f
JH
2392 for (; da; da = da->next)
2393 {
2394 #ifndef STAND_ALONE
2395 if (ignore_target_hosts != NULL &&
2396 verify_check_this_host(&ignore_target_hosts, NULL,
2397 host->name, da->address, NULL) == OK)
2398 {
2399 DEBUG(D_host_lookup)
2400 debug_printf("ignored host %s [%s]\n", host->name, da->address);
2401 continue;
2402 }
2403 #endif
059ec3d9 2404
d7978c0f
JH
2405 /* If this is the first address, stick it in the given host block,
2406 and change the name if the returned RR has a different name. */
059ec3d9 2407
d7978c0f
JH
2408 if (thishostlast == NULL)
2409 {
2410 if (strcmpic(host->name, rr->name) != 0)
2411 host->name = string_copy_dnsdomain(rr->name);
2412 host->address = da->address;
2413 host->sort_key = host->mx * 1000 + random_number(500) + randoffset;
2414 host->status = hstatus_unknown;
2415 host->why = hwhy_unknown;
2416 thishostlast = host;
2417 }
059ec3d9 2418
d7978c0f
JH
2419 /* Not the first address. Check for, and ignore, duplicates. Then
2420 insert in the chain at a random point. */
059ec3d9 2421
d7978c0f
JH
2422 else
2423 {
2424 int new_sort_key;
2425 host_item *next;
2426
2427 /* End of our local chain is specified by "thishostlast". */
2428
2429 for (next = host;; next = next->next)
2430 {
2431 if (Ustrcmp(CS da->address, next->address) == 0) break;
2432 if (next == thishostlast) { next = NULL; break; }
2433 }
2434 if (next != NULL) continue; /* With loop for next address */
2435
2436 /* Not a duplicate */
2437
2438 new_sort_key = host->mx * 1000 + random_number(500) + randoffset;
f3ebb786 2439 next = store_get(sizeof(host_item), FALSE);
d7978c0f
JH
2440
2441 /* New address goes first: insert the new block after the first one
2442 (so as not to disturb the original pointer) but put the new address
2443 in the original block. */
2444
2445 if (new_sort_key < host->sort_key)
2446 {
2447 *next = *host; /* Copies port */
2448 host->next = next;
2449 host->address = da->address;
2450 host->sort_key = new_sort_key;
2451 if (thishostlast == host) thishostlast = next; /* Local last */
2452 if (*lastptr == host) *lastptr = next; /* Global last */
2453 }
2454
2455 /* Otherwise scan down the addresses for this host to find the
2456 one to insert after. */
2457
2458 else
2459 {
2460 host_item *h = host;
2461 while (h != thishostlast)
2462 {
2463 if (new_sort_key < h->next->sort_key) break;
2464 h = h->next;
2465 }
2466 *next = *h; /* Copies port */
2467 h->next = next;
2468 next->address = da->address;
2469 next->sort_key = new_sort_key;
2470 if (h == thishostlast) thishostlast = next; /* Local last */
2471 if (h == *lastptr) *lastptr = next; /* Global last */
2472 }
2473 }
059ec3d9
PH
2474 }
2475 }
2476 }
2477
2546388c 2478/* Control gets here only if the second lookup (the A record) succeeded.
059ec3d9
PH
2479However, the address may not be filled in if it was ignored. */
2480
2546388c
JH
2481return host->address
2482 ? HOST_FOUND
2483 : dnssec_fail
2484 ? HOST_FIND_SECURITY
2485 : HOST_IGNORED;
059ec3d9
PH
2486}
2487
2488
2489
2490
2491/*************************************************
1349e1e5 2492* Find IP addresses and host names via DNS *
059ec3d9
PH
2493*************************************************/
2494
1349e1e5
PH
2495/* The input is a host_item structure with the name field filled in and the
2496address field set to NULL. This may be in a chain of other host items. The
2497lookup may result in more than one IP address, in which case we must created
2498new host blocks for the additional addresses, and insert them into the chain.
2499The original name may not be fully qualified. Use the fully_qualified_name
2500argument to return the official name, as returned by the resolver.
059ec3d9
PH
2501
2502Arguments:
2503 host point to initial host item
2504 ignore_target_hosts a list of hosts to ignore
2505 whichrrs flags indicating which RRs to look for:
2506 HOST_FIND_BY_SRV => look for SRV
2507 HOST_FIND_BY_MX => look for MX
66387a73
JH
2508 HOST_FIND_BY_A => look for A
2509 HOST_FIND_BY_AAAA => look for AAAA
059ec3d9
PH
2510 also flags indicating how the lookup is done
2511 HOST_FIND_QUALIFY_SINGLE ) passed to the
2512 HOST_FIND_SEARCH_PARENTS ) resolver
66387a73
JH
2513 HOST_FIND_IPV4_FIRST => reverse usual result ordering
2514 HOST_FIND_IPV4_ONLY => MX results elide ipv6
059ec3d9
PH
2515 srv_service when SRV used, the service name
2516 srv_fail_domains DNS errors for these domains => assume nonexist
2517 mx_fail_domains DNS errors for these domains => assume nonexist
7cd171b7
JH
2518 dnssec_d.request => make dnssec request: domainlist
2519 dnssec_d.require => ditto and nonexist failures
059ec3d9
PH
2520 fully_qualified_name if not NULL, return fully-qualified name
2521 removed set TRUE if local host was removed from the list
2522
2523Returns: HOST_FIND_FAILED Failed to find the host or domain;
2524 if there was a syntax error,
2525 host_find_failed_syntax is set.
2526 HOST_FIND_AGAIN Could not resolve at this time
2546388c 2527 HOST_FIND_SECURITY dnsssec required but not acheived
059ec3d9
PH
2528 HOST_FOUND Host found
2529 HOST_FOUND_LOCAL The lowest MX record points to this
2530 machine, if MX records were found, or
2531 an A record that was found contains
2532 an address of the local host
2533*/
2534
2535int
55414b25 2536host_find_bydns(host_item *host, const uschar *ignore_target_hosts, int whichrrs,
059ec3d9 2537 uschar *srv_service, uschar *srv_fail_domains, uschar *mx_fail_domains,
7cd171b7 2538 const dnssec_domains *dnssec_d,
55414b25 2539 const uschar **fully_qualified_name, BOOL *removed)
059ec3d9
PH
2540{
2541host_item *h, *last;
059ec3d9
PH
2542int rc = DNS_FAIL;
2543int ind_type = 0;
2544int yield;
8743d3ac 2545dns_answer * dnsa = store_get_dns_answer();
059ec3d9 2546dns_scan dnss;
7cd171b7
JH
2547BOOL dnssec_require = dnssec_d
2548 && match_isinlist(host->name, CUSS &dnssec_d->require,
8c51eead 2549 0, NULL, NULL, MCL_DOMAIN, TRUE, NULL) == OK;
783b385f 2550BOOL dnssec_request = dnssec_require
7cd171b7
JH
2551 || ( dnssec_d
2552 && match_isinlist(host->name, CUSS &dnssec_d->request,
2553 0, NULL, NULL, MCL_DOMAIN, TRUE, NULL) == OK);
783b385f 2554dnssec_status_t dnssec;
059ec3d9
PH
2555
2556/* Set the default fully qualified name to the incoming name, initialize the
2557resolver if necessary, set up the relevant options, and initialize the flag
2558that gets set for DNS syntax check errors. */
2559
2560if (fully_qualified_name != NULL) *fully_qualified_name = host->name;
2561dns_init((whichrrs & HOST_FIND_QUALIFY_SINGLE) != 0,
8c51eead 2562 (whichrrs & HOST_FIND_SEARCH_PARENTS) != 0,
1f155f8e 2563 dnssec_request);
8768d548 2564f.host_find_failed_syntax = FALSE;
059ec3d9
PH
2565
2566/* First, if requested, look for SRV records. The service name is given; we
221dff13 2567assume TCP protocol. DNS domain names are constrained to a maximum of 256
059ec3d9
PH
2568characters, so the code below should be safe. */
2569
94759fce 2570if (whichrrs & HOST_FIND_BY_SRV)
059ec3d9 2571 {
d12746bc
JH
2572 gstring * g;
2573 uschar * temp_fully_qualified_name;
059ec3d9
PH
2574 int prefix_length;
2575
d12746bc
JH
2576 g = string_fmt_append(NULL, "_%s._tcp.%n%.256s",
2577 srv_service, &prefix_length, host->name);
2578 temp_fully_qualified_name = string_from_gstring(g);
059ec3d9
PH
2579 ind_type = T_SRV;
2580
2581 /* Search for SRV records. If the fully qualified name is different to
2582 the input name, pass back the new original domain, without the prepended
2583 magic. */
2584
783b385f
JH
2585 dnssec = DS_UNK;
2586 lookup_dnssec_authenticated = NULL;
8743d3ac 2587 rc = dns_lookup_timerwrap(dnsa, temp_fully_qualified_name, ind_type,
d12746bc 2588 CUSS &temp_fully_qualified_name);
783b385f 2589
221dff13
HSHR
2590 DEBUG(D_dns)
2591 if ((dnssec_request || dnssec_require)
8743d3ac
JH
2592 && !dns_is_secure(dnsa)
2593 && dns_is_aa(dnsa))
221dff13
HSHR
2594 debug_printf("DNS lookup of %.256s (SRV) requested AD, but got AA\n", host->name);
2595
783b385f
JH
2596 if (dnssec_request)
2597 {
8743d3ac 2598 if (dns_is_secure(dnsa))
783b385f
JH
2599 { dnssec = DS_YES; lookup_dnssec_authenticated = US"yes"; }
2600 else
2601 { dnssec = DS_NO; lookup_dnssec_authenticated = US"no"; }
2602 }
4e0983dc 2603
d12746bc 2604 if (temp_fully_qualified_name != g->s && fully_qualified_name != NULL)
059ec3d9
PH
2605 *fully_qualified_name = temp_fully_qualified_name + prefix_length;
2606
2607 /* On DNS failures, we give the "try again" error unless the domain is
2608 listed as one for which we continue. */
2609
8743d3ac 2610 if (rc == DNS_SUCCEED && dnssec_require && !dns_is_secure(dnsa))
8c51eead
JH
2611 {
2612 log_write(L_host_lookup_failed, LOG_MAIN,
2613 "dnssec fail on SRV for %.256s", host->name);
2614 rc = DNS_FAIL;
2615 }
059ec3d9
PH
2616 if (rc == DNS_FAIL || rc == DNS_AGAIN)
2617 {
e7726cbf 2618 #ifndef STAND_ALONE
55414b25
JH
2619 if (match_isinlist(host->name, CUSS &srv_fail_domains, 0, NULL, NULL,
2620 MCL_DOMAIN, TRUE, NULL) != OK)
e7726cbf 2621 #endif
8c51eead 2622 { yield = HOST_FIND_AGAIN; goto out; }
059ec3d9
PH
2623 DEBUG(D_host_lookup) debug_printf("DNS_%s treated as DNS_NODATA "
2624 "(domain in srv_fail_domains)\n", (rc == DNS_FAIL)? "FAIL":"AGAIN");
2625 }
2626 }
2627
2628/* If we did not find any SRV records, search the DNS for MX records, if
2629requested to do so. If the result is DNS_NOMATCH, it means there is no such
2630domain, and there's no point in going on to look for address records with the
2631same domain. The result will be DNS_NODATA if the domain exists but has no MX
2632records. On DNS failures, we give the "try again" error unless the domain is
2633listed as one for which we continue. */
2634
2546388c 2635if (rc != DNS_SUCCEED && whichrrs & HOST_FIND_BY_MX)
059ec3d9
PH
2636 {
2637 ind_type = T_MX;
783b385f
JH
2638 dnssec = DS_UNK;
2639 lookup_dnssec_authenticated = NULL;
8743d3ac 2640 rc = dns_lookup_timerwrap(dnsa, host->name, ind_type, fully_qualified_name);
783b385f 2641
221dff13 2642 DEBUG(D_dns)
2546388c 2643 if ( (dnssec_request || dnssec_require)
8743d3ac
JH
2644 && !dns_is_secure(dnsa)
2645 && dns_is_aa(dnsa))
cf3d165f 2646 debug_printf("DNS lookup of %.256s (MX) requested AD, but got AA\n", host->name);
221dff13 2647
783b385f 2648 if (dnssec_request)
8743d3ac 2649 if (dns_is_secure(dnsa))
94431adb 2650 {
979c462e 2651 DEBUG(D_host_lookup) debug_printf("%s (MX resp) DNSSEC\n", host->name);
cf2b569e
JH
2652 dnssec = DS_YES; lookup_dnssec_authenticated = US"yes";
2653 }
783b385f 2654 else
cf2b569e
JH
2655 {
2656 dnssec = DS_NO; lookup_dnssec_authenticated = US"no";
2657 }
4e0983dc 2658
8c51eead
JH
2659 switch (rc)
2660 {
2661 case DNS_NOMATCH:
2662 yield = HOST_FIND_FAILED; goto out;
2663
2664 case DNS_SUCCEED:
8743d3ac 2665 if (!dnssec_require || dns_is_secure(dnsa))
8c51eead 2666 break;
2546388c
JH
2667 DEBUG(D_host_lookup)
2668 debug_printf("dnssec fail on MX for %.256s", host->name);
2669#ifndef STAND_ALONE
2670 if (match_isinlist(host->name, CUSS &mx_fail_domains, 0, NULL, NULL,
2671 MCL_DOMAIN, TRUE, NULL) != OK)
2672 { yield = HOST_FIND_SECURITY; goto out; }
2673#endif
8c51eead 2674 rc = DNS_FAIL;
cf2b569e 2675 /*FALLTHROUGH*/
8c51eead
JH
2676
2677 case DNS_FAIL:
2678 case DNS_AGAIN:
2546388c 2679#ifndef STAND_ALONE
55414b25
JH
2680 if (match_isinlist(host->name, CUSS &mx_fail_domains, 0, NULL, NULL,
2681 MCL_DOMAIN, TRUE, NULL) != OK)
2546388c 2682#endif
8c51eead
JH
2683 { yield = HOST_FIND_AGAIN; goto out; }
2684 DEBUG(D_host_lookup) debug_printf("DNS_%s treated as DNS_NODATA "
2685 "(domain in mx_fail_domains)\n", (rc == DNS_FAIL)? "FAIL":"AGAIN");
2686 break;
059ec3d9
PH
2687 }
2688 }
2689
2690/* If we haven't found anything yet, and we are requested to do so, try for an
2691A or AAAA record. If we find it (or them) check to see that it isn't the local
2692host. */
2693
2694if (rc != DNS_SUCCEED)
2695 {
66387a73 2696 if (!(whichrrs & (HOST_FIND_BY_A | HOST_FIND_BY_AAAA)))
059ec3d9
PH
2697 {
2698 DEBUG(D_host_lookup) debug_printf("Address records are not being sought\n");
8c51eead
JH
2699 yield = HOST_FIND_FAILED;
2700 goto out;
059ec3d9
PH
2701 }
2702
2703 last = host; /* End of local chainlet */
2704 host->mx = MX_NONE;
2705 host->port = PORT_NONE;
cf2b569e 2706 host->dnssec = DS_UNK;
783b385f 2707 lookup_dnssec_authenticated = NULL;
059ec3d9 2708 rc = set_address_from_dns(host, &last, ignore_target_hosts, FALSE,
66387a73 2709 fully_qualified_name, dnssec_request, dnssec_require, whichrrs);
059ec3d9
PH
2710
2711 /* If one or more address records have been found, check that none of them
2712 are local. Since we know the host items all have their IP addresses
2713 inserted, host_scan_for_local_hosts() can only return HOST_FOUND or
2714 HOST_FOUND_LOCAL. We do not need to scan for duplicate IP addresses here,
2715 because set_address_from_dns() removes them. */
2716
2717 if (rc == HOST_FOUND)
2718 rc = host_scan_for_local_hosts(host, &last, removed);
2719 else
2720 if (rc == HOST_IGNORED) rc = HOST_FIND_FAILED; /* No special action */
2721
2722 DEBUG(D_host_lookup)
d7978c0f 2723 if (host->address)
059ec3d9 2724 {
d7978c0f 2725 if (fully_qualified_name)
059ec3d9 2726 debug_printf("fully qualified name = %s\n", *fully_qualified_name);
d7978c0f 2727 for (host_item * h = host; h != last->next; h = h->next)
059ec3d9 2728 debug_printf("%s %s mx=%d sort=%d %s\n", h->name,
d7978c0f
JH
2729 h->address ? h->address : US"<null>", h->mx, h->sort_key,
2730 h->status >= hstatus_unusable ? US"*" : US"");
059ec3d9 2731 }
059ec3d9 2732
8c51eead
JH
2733 yield = rc;
2734 goto out;
059ec3d9
PH
2735 }
2736
2737/* We have found one or more MX or SRV records. Sort them according to
2738precedence. Put the data for the first one into the existing host block, and
2739insert new host_item blocks into the chain for the remainder. For equal
2740precedences one is supposed to randomize the order. To make this happen, the
2741sorting is actually done on the MX value * 1000 + a random number. This is put
2742into a host field called sort_key.
2743
2744In the case of hosts with both IPv6 and IPv4 addresses, we want to choose the
2745IPv6 address in preference. At this stage, we don't know what kind of address
2746the host has. We choose a random number < 500; if later we find an A record
2747first, we add 500 to the random number. Then for any other address records, we
2748use random numbers in the range 0-499 for AAAA records and 500-999 for A
2749records.
2750
2751At this point we remove any duplicates that point to the same host, retaining
2752only the one with the lowest precedence. We cannot yet check for precedence
2753greater than that of the local host, because that test cannot be properly done
2754until the addresses have been found - an MX record may point to a name for this
2755host which is not the primary hostname. */
2756
2757last = NULL; /* Indicates that not even the first item is filled yet */
2758
8743d3ac 2759for (dns_record * rr = dns_next_rr(dnsa, &dnss, RESET_ANSWERS);
dd708fd7 2760 rr;
8743d3ac 2761 rr = dns_next_rr(dnsa, &dnss, RESET_NEXT)) if (rr->type == ind_type)
059ec3d9 2762 {
8c513105 2763 int precedence, weight;
1349e1e5 2764 int port = PORT_NONE;
dd708fd7 2765 const uschar * s = rr->data; /* MUST be unsigned for GETSHORT */
059ec3d9
PH
2766 uschar data[256];
2767
059ec3d9
PH
2768 GETSHORT(precedence, s); /* Pointer s is advanced */
2769
2770 /* For MX records, we use a random "weight" which causes multiple records of
2771 the same precedence to sort randomly. */
2772
2773 if (ind_type == T_MX)
059ec3d9 2774 weight = random_number(500);
059ec3d9
PH
2775 else
2776 {
8c513105
JH
2777 /* SRV records are specified with a port and a weight. The weight is used
2778 in a special algorithm. However, to start with, we just use it to order the
2779 records of equal priority (precedence). */
059ec3d9
PH
2780 GETSHORT(weight, s);
2781 GETSHORT(port, s);
2782 }
2783
2784 /* Get the name of the host pointed to. */
2785
8743d3ac 2786 (void)dn_expand(dnsa->answer, dnsa->answer + dnsa->answerlen, s,
059ec3d9
PH
2787 (DN_EXPAND_ARG4_TYPE)data, sizeof(data));
2788
2789 /* Check that we haven't already got this host on the chain; if we have,
2790 keep only the lower precedence. This situation shouldn't occur, but you
2791 never know what junk might get into the DNS (and this case has been seen on
2792 more than one occasion). */
2793
8c513105 2794 if (last) /* This is not the first record */
059ec3d9
PH
2795 {
2796 host_item *prev = NULL;
2797
2798 for (h = host; h != last->next; prev = h, h = h->next)
059ec3d9
PH
2799 if (strcmpic(h->name, data) == 0)
2800 {
2801 DEBUG(D_host_lookup)
2802 debug_printf("discarded duplicate host %s (MX=%d)\n", data,
8c513105 2803 precedence > h->mx ? precedence : h->mx);
059ec3d9
PH
2804 if (precedence >= h->mx) goto NEXT_MX_RR; /* Skip greater precedence */
2805 if (h == host) /* Override first item */
2806 {
2807 h->mx = precedence;
2808 host->sort_key = precedence * 1000 + weight;
2809 goto NEXT_MX_RR;
2810 }
2811
2812 /* Unwanted host item is not the first in the chain, so we can get
2813 get rid of it by cutting it out. */
2814
2815 prev->next = h->next;
2816 if (h == last) last = prev;
2817 break;
2818 }
059ec3d9
PH
2819 }
2820
2821 /* If this is the first MX or SRV record, put the data into the existing host
2822 block. Otherwise, add a new block in the correct place; if it has to be
2823 before the first block, copy the first block's data to a new second block. */
2824
8ac90765 2825 if (!last)
059ec3d9
PH
2826 {
2827 host->name = string_copy_dnsdomain(data);
2828 host->address = NULL;
2829 host->port = port;
2830 host->mx = precedence;
2831 host->sort_key = precedence * 1000 + weight;
2832 host->status = hstatus_unknown;
2833 host->why = hwhy_unknown;
783b385f 2834 host->dnssec = dnssec;
059ec3d9
PH
2835 last = host;
2836 }
8c513105 2837 else
059ec3d9
PH
2838
2839 /* Make a new host item and seek the correct insertion place */
059ec3d9
PH
2840 {
2841 int sort_key = precedence * 1000 + weight;
f3ebb786 2842 host_item *next = store_get(sizeof(host_item), FALSE);
059ec3d9
PH
2843 next->name = string_copy_dnsdomain(data);
2844 next->address = NULL;
2845 next->port = port;
2846 next->mx = precedence;
2847 next->sort_key = sort_key;
2848 next->status = hstatus_unknown;
2849 next->why = hwhy_unknown;
783b385f 2850 next->dnssec = dnssec;
059ec3d9
PH
2851 next->last_try = 0;
2852
2853 /* Handle the case when we have to insert before the first item. */
2854
2855 if (sort_key < host->sort_key)
2856 {
2857 host_item htemp;
2858 htemp = *host;
2859 *host = *next;
2860 *next = htemp;
2861 host->next = next;
2862 if (last == host) last = next;
2863 }
8c513105 2864 else
059ec3d9
PH
2865
2866 /* Else scan down the items we have inserted as part of this exercise;
2867 don't go further. */
059ec3d9
PH
2868 {
2869 for (h = host; h != last; h = h->next)
059ec3d9
PH
2870 if (sort_key < h->next->sort_key)
2871 {
2872 next->next = h->next;
2873 h->next = next;
2874 break;
2875 }
059ec3d9
PH
2876
2877 /* Join on after the last host item that's part of this
2878 processing if we haven't stopped sooner. */
2879
2880 if (h == last)
2881 {
2882 next->next = last->next;
2883 last->next = next;
2884 last = next;
2885 }
2886 }
2887 }
2888
2889 NEXT_MX_RR: continue;
2890 }
2891
dc8091e7
JH
2892if (!last) /* No rr of correct type; give up */
2893 {
2894 yield = HOST_FIND_FAILED;
2895 goto out;
2896 }
2897
059ec3d9
PH
2898/* If the list of hosts was obtained from SRV records, there are two things to
2899do. First, if there is only one host, and it's name is ".", it means there is
2900no SMTP service at this domain. Otherwise, we have to sort the hosts of equal
2901priority according to their weights, using an algorithm that is defined in RFC
29022782. The hosts are currently sorted by priority and weight. For each priority
2903group we have to pick off one host and put it first, and then repeat for any
2904remaining in the same priority group. */
2905
2906if (ind_type == T_SRV)
2907 {
d7978c0f 2908 host_item ** pptr;
059ec3d9
PH
2909
2910 if (host == last && host->name[0] == 0)
2911 {
2912 DEBUG(D_host_lookup) debug_printf("the single SRV record is \".\"\n");
8c51eead
JH
2913 yield = HOST_FIND_FAILED;
2914 goto out;
059ec3d9
PH
2915 }
2916
2917 DEBUG(D_host_lookup)
2918 {
2919 debug_printf("original ordering of hosts from SRV records:\n");
2920 for (h = host; h != last->next; h = h->next)
2921 debug_printf(" %s P=%d W=%d\n", h->name, h->mx, h->sort_key % 1000);
2922 }
2923
dc8091e7 2924 for (pptr = &host, h = host; h != last; pptr = &h->next, h = h->next)
059ec3d9
PH
2925 {
2926 int sum = 0;
2927 host_item *hh;
2928
2929 /* Find the last following host that has the same precedence. At the same
2930 time, compute the sum of the weights and the running totals. These can be
2931 stored in the sort_key field. */
2932
2933 for (hh = h; hh != last; hh = hh->next)
2934 {
2935 int weight = hh->sort_key % 1000; /* was precedence * 1000 + weight */
2936 sum += weight;
2937 hh->sort_key = sum;
2938 if (hh->mx != hh->next->mx) break;
2939 }
2940
2941 /* If there's more than one host at this precedence (priority), we need to
2942 pick one to go first. */
2943
2944 if (hh != h)
2945 {
2946 host_item *hhh;
2947 host_item **ppptr;
2948 int randomizer = random_number(sum + 1);
2949
2950 for (ppptr = pptr, hhh = h;
2951 hhh != hh;
8c513105
JH
2952 ppptr = &hhh->next, hhh = hhh->next)
2953 if (hhh->sort_key >= randomizer)
2954 break;
059ec3d9
PH
2955
2956 /* hhh now points to the host that should go first; ppptr points to the
2957 place that points to it. Unfortunately, if the start of the minilist is
2958 the start of the entire list, we can't just swap the items over, because
2959 we must not change the value of host, since it is passed in from outside.
2960 One day, this could perhaps be changed.
2961
2962 The special case is fudged by putting the new item *second* in the chain,
2963 and then transferring the data between the first and second items. We
2964 can't just swap the first and the chosen item, because that would mean
2965 that an item with zero weight might no longer be first. */
2966
2967 if (hhh != h)
2968 {
2969 *ppptr = hhh->next; /* Cuts it out of the chain */
2970
2971 if (h == host)
2972 {
2973 host_item temp = *h;
2974 *h = *hhh;
2975 *hhh = temp;
2976 hhh->next = temp.next;
2977 h->next = hhh;
2978 }
059ec3d9
PH
2979 else
2980 {
2981 hhh->next = h; /* The rest of the chain follows it */
2982 *pptr = hhh; /* It takes the place of h */
2983 h = hhh; /* It's now the start of this minilist */
2984 }
2985 }
2986 }
2987
2988 /* A host has been chosen to be first at this priority and h now points
2989 to this host. There may be others at the same priority, or others at a
2990 different priority. Before we leave this host, we need to put back a sort
2991 key of the traditional MX kind, in case this host is multihomed, because
2992 the sort key is used for ordering the multiple IP addresses. We do not need
2993 to ensure that these new sort keys actually reflect the order of the hosts,
2994 however. */
2995
2996 h->sort_key = h->mx * 1000 + random_number(500);
2997 } /* Move on to the next host */
2998 }
2999
1349e1e5
PH
3000/* Now we have to find IP addresses for all the hosts. We have ensured above
3001that the names in all the host items are unique. Before release 4.61 we used to
3002process records from the additional section in the DNS packet that returned the
3003MX or SRV records. However, a DNS name server is free to drop any resource
3004records from the additional section. In theory, this has always been a
3005potential problem, but it is exacerbated by the advent of IPv6. If a host had
3006several IPv4 addresses and some were not in the additional section, at least
3007Exim would try the others. However, if a host had both IPv4 and IPv6 addresses
3008and all the IPv4 (say) addresses were absent, Exim would try only for a IPv6
3009connection, and never try an IPv4 address. When there was only IPv4
3010connectivity, this was a disaster that did in practice occur.
3011
3012So, from release 4.61 onwards, we always search for A and AAAA records
3013explicitly. The names shouldn't point to CNAMES, but we use the general lookup
3014function that handles them, just in case. If any lookup gives a soft error,
3015change the default yield.
059ec3d9
PH
3016
3017For these DNS lookups, we must disable qualify_single and search_parents;
3018otherwise invalid host names obtained from MX or SRV records can cause trouble
3019if they happen to match something local. */
3020
1349e1e5 3021yield = HOST_FIND_FAILED; /* Default yield */
8c51eead
JH
3022dns_init(FALSE, FALSE, /* Disable qualify_single and search_parents */
3023 dnssec_request || dnssec_require);
059ec3d9
PH
3024
3025for (h = host; h != last->next; h = h->next)
3026 {
dc8091e7
JH
3027 if (h->address) continue; /* Inserted by a multihomed host */
3028
8c51eead 3029 rc = set_address_from_dns(h, &last, ignore_target_hosts, allow_mx_to_ip,
66387a73
JH
3030 NULL, dnssec_request, dnssec_require,
3031 whichrrs & HOST_FIND_IPV4_ONLY
3032 ? HOST_FIND_BY_A : HOST_FIND_BY_A | HOST_FIND_BY_AAAA);
059ec3d9
PH
3033 if (rc != HOST_FOUND)
3034 {
3035 h->status = hstatus_unusable;
2546388c 3036 switch (rc)
059ec3d9 3037 {
66387a73
JH
3038 case HOST_FIND_AGAIN: yield = rc; h->why = hwhy_deferred; break;
3039 case HOST_FIND_SECURITY: yield = rc; h->why = hwhy_insecure; break;
3040 case HOST_IGNORED: h->why = hwhy_ignored; break;
3041 default: h->why = hwhy_failed; break;
059ec3d9 3042 }
059ec3d9
PH
3043 }
3044 }
3045
3046/* Scan the list for any hosts that are marked unusable because they have
3047been explicitly ignored, and remove them from the list, as if they did not
3048exist. If we end up with just a single, ignored host, flatten its fields as if
3049nothing was found. */
3050
2546388c 3051if (ignore_target_hosts)
059ec3d9
PH
3052 {
3053 host_item *prev = NULL;
3054 for (h = host; h != last->next; h = h->next)
3055 {
3056 REDO:
3057 if (h->why != hwhy_ignored) /* Non ignored host, just continue */
3058 prev = h;
3059 else if (prev == NULL) /* First host is ignored */
3060 {
3061 if (h != last) /* First is not last */
3062 {
3063 if (h->next == last) last = h; /* Overwrite it with next */
3064 *h = *(h->next); /* and reprocess it. */
3065 goto REDO; /* C should have redo, like Perl */
3066 }
3067 }
3068 else /* Ignored host is not first - */
3069 { /* cut it out */
3070 prev->next = h->next;
3071 if (h == last) last = prev;
3072 }
3073 }
3074
3075 if (host->why == hwhy_ignored) host->address = NULL;
3076 }
3077
3078/* There is still one complication in the case of IPv6. Although the code above
3079arranges that IPv6 addresses take precedence over IPv4 addresses for multihomed
3080hosts, it doesn't do this for addresses that apply to different hosts with the
3081same MX precedence, because the sorting on MX precedence happens first. So we
3082have to make another pass to check for this case. We ensure that, within a
3083single MX preference value, IPv6 addresses come first. This can separate the
3084addresses of a multihomed host, but that should not matter. */
3085
3086#if HAVE_IPV6
2546388c 3087if (h != last && !disable_ipv6) for (h = host; h != last; h = h->next)
059ec3d9 3088 {
2546388c
JH
3089 host_item temp;
3090 host_item *next = h->next;
3091
66387a73
JH
3092 if ( h->mx != next->mx /* If next is different MX */
3093 || !h->address /* OR this one is unset */
3094 )
3095 continue; /* move on to next */
3096
3097 if ( whichrrs & HOST_FIND_IPV4_FIRST
3098 ? !Ustrchr(h->address, ':') /* OR this one is IPv4 */
3099 || next->address
3100 && Ustrchr(next->address, ':') /* OR next is IPv6 */
3101
3102 : Ustrchr(h->address, ':') /* OR this one is IPv6 */
3103 || next->address
3104 && !Ustrchr(next->address, ':') /* OR next is IPv4 */
3105 )
2546388c 3106 continue; /* move on to next */
66387a73 3107
2546388c
JH
3108 temp = *h; /* otherwise, swap */
3109 temp.next = next->next;
3110 *h = *next;
3111 h->next = next;
3112 *next = temp;
059ec3d9
PH
3113 }
3114#endif
3115
059ec3d9
PH
3116/* Remove any duplicate IP addresses and then scan the list of hosts for any
3117whose IP addresses are on the local host. If any are found, all hosts with the
3118same or higher MX values are removed. However, if the local host has the lowest
3119numbered MX, then HOST_FOUND_LOCAL is returned. Otherwise, if at least one host
3120with an IP address is on the list, HOST_FOUND is returned. Otherwise,
3121HOST_FIND_FAILED is returned, but in this case do not update the yield, as it
3122might have been set to HOST_FIND_AGAIN just above here. If not, it will already
3123be HOST_FIND_FAILED. */
3124
3125host_remove_duplicates(host, &last);
3126rc = host_scan_for_local_hosts(host, &last, removed);
3127if (rc != HOST_FIND_FAILED) yield = rc;
3128
3129DEBUG(D_host_lookup)
3130 {
d7978c0f 3131 if (fully_qualified_name)
059ec3d9
PH
3132 debug_printf("fully qualified name = %s\n", *fully_qualified_name);
3133 debug_printf("host_find_bydns yield = %s (%d); returned hosts:\n",
d7978c0f
JH
3134 yield == HOST_FOUND ? "HOST_FOUND" :
3135 yield == HOST_FOUND_LOCAL ? "HOST_FOUND_LOCAL" :
3136 yield == HOST_FIND_SECURITY ? "HOST_FIND_SECURITY" :
3137 yield == HOST_FIND_AGAIN ? "HOST_FIND_AGAIN" :
3138 yield == HOST_FIND_FAILED ? "HOST_FIND_FAILED" : "?",
059ec3d9
PH
3139 yield);
3140 for (h = host; h != last->next; h = h->next)
3141 {
805c9d53
JH
3142 debug_printf(" %s %s MX=%d %s", h->name,
3143 !h->address ? US"<null>" : h->address, h->mx,
3144 h->dnssec == DS_YES ? US"DNSSEC " : US"");
059ec3d9
PH
3145 if (h->port != PORT_NONE) debug_printf("port=%d ", h->port);
3146 if (h->status >= hstatus_unusable) debug_printf("*");
3147 debug_printf("\n");
3148 }
3149 }
3150
8c51eead
JH
3151out:
3152
3153dns_init(FALSE, FALSE, FALSE); /* clear the dnssec bit for getaddrbyname */
059ec3d9
PH
3154return yield;
3155}
3156
30795c5e
JH
3157
3158
3159
3160#ifdef SUPPORT_DANE
3161/* Lookup TLSA record for host/port.
3162Return: OK success with dnssec; DANE mode
3163 DEFER Do not use this host now, may retry later
3164 FAIL_FORCED No TLSA record; DANE not usable
3165 FAIL Do not use this connection
3166*/
3167
3168int
3169tlsa_lookup(const host_item * host, dns_answer * dnsa, BOOL dane_required)
3170{
3171uschar buffer[300];
3172const uschar * fullname = buffer;
3173int rc;
3174BOOL sec;
3175
3176/* TLSA lookup string */
3177(void)sprintf(CS buffer, "_%d._tcp.%.256s", host->port, host->name);
3178
3179rc = dns_lookup_timerwrap(dnsa, buffer, T_TLSA, &fullname);
3180sec = dns_is_secure(dnsa);
3181DEBUG(D_transport)
3182 debug_printf("TLSA lookup ret %d %sDNSSEC\n", rc, sec ? "" : "not ");
3183
3184switch (rc)
3185 {
3186 case DNS_AGAIN:
3187 return DEFER; /* just defer this TLS'd conn */
3188
3189 case DNS_SUCCEED:
3190 if (sec)
3191 {
3192 DEBUG(D_transport)
3193 {
3194 dns_scan dnss;
3195 for (dns_record * rr = dns_next_rr(dnsa, &dnss, RESET_ANSWERS); rr;
3196 rr = dns_next_rr(dnsa, &dnss, RESET_NEXT))
3197 if (rr->type == T_TLSA && rr->size > 3)
3198 {
3199 uint16_t payload_length = rr->size - 3;
3200 uschar s[MAX_TLSA_EXPANDED_SIZE], * sp = s, * p = US rr->data;
3201
3202 sp += sprintf(CS sp, "%d ", *p++); /* usage */
3203 sp += sprintf(CS sp, "%d ", *p++); /* selector */
3204 sp += sprintf(CS sp, "%d ", *p++); /* matchtype */
3205 while (payload_length-- > 0 && sp-s < (MAX_TLSA_EXPANDED_SIZE - 4))
3206 sp += sprintf(CS sp, "%02x", *p++);
3207
3208 debug_printf(" %s\n", s);
3209 }
3210 }
3211 return OK;
3212 }
3213 log_write(0, LOG_MAIN,
3214 "DANE error: TLSA lookup for %s not DNSSEC", host->name);
3215 /*FALLTRHOUGH*/
3216
3217 case DNS_NODATA: /* no TLSA RR for this lookup */
3218 case DNS_NOMATCH: /* no records at all for this lookup */
3219 return dane_required ? FAIL : FAIL_FORCED;
3220
3221 default:
3222 case DNS_FAIL:
3223 return dane_required ? FAIL : DEFER;
3224 }
3225}
3226#endif /*SUPPORT_DANE*/
3227
3228
3229
059ec3d9
PH
3230/*************************************************
3231**************************************************
3232* Stand-alone test program *
3233**************************************************
3234*************************************************/
3235
3236#ifdef STAND_ALONE
3237
059ec3d9
PH
3238int main(int argc, char **cargv)
3239{
3240host_item h;
66387a73 3241int whichrrs = HOST_FIND_BY_MX | HOST_FIND_BY_A | HOST_FIND_BY_AAAA;
059ec3d9
PH
3242BOOL byname = FALSE;
3243BOOL qualify_single = TRUE;
3244BOOL search_parents = FALSE;
8c51eead
JH
3245BOOL request_dnssec = FALSE;
3246BOOL require_dnssec = FALSE;
059ec3d9
PH
3247uschar **argv = USS cargv;
3248uschar buffer[256];
3249
322050c2 3250disable_ipv6 = FALSE;
059ec3d9
PH
3251primary_hostname = US"";
3252store_pool = POOL_MAIN;
3253debug_selector = D_host_lookup|D_interface;
3254debug_file = stdout;
3255debug_fd = fileno(debug_file);
3256
3257printf("Exim stand-alone host functions test\n");
3258
3259host_find_interfaces();
3260debug_selector = D_host_lookup | D_dns;
3261
3262if (argc > 1) primary_hostname = argv[1];
3263
3264/* So that debug level changes can be done first */
3265
8c51eead 3266dns_init(qualify_single, search_parents, FALSE);
059ec3d9
PH
3267
3268printf("Testing host lookup\n");
3269printf("> ");
3270while (Ufgets(buffer, 256, stdin) != NULL)
3271 {
3272 int rc;
3273 int len = Ustrlen(buffer);
3274 uschar *fully_qualified_name;
3275
3276 while (len > 0 && isspace(buffer[len-1])) len--;
3277 buffer[len] = 0;
3278
3279 if (Ustrcmp(buffer, "q") == 0) break;
3280
3281 if (Ustrcmp(buffer, "byname") == 0) byname = TRUE;
3282 else if (Ustrcmp(buffer, "no_byname") == 0) byname = FALSE;
66387a73 3283 else if (Ustrcmp(buffer, "a_only") == 0) whichrrs = HOST_FIND_BY_A | HOST_FIND_BY_AAAA;
059ec3d9
PH
3284 else if (Ustrcmp(buffer, "mx_only") == 0) whichrrs = HOST_FIND_BY_MX;
3285 else if (Ustrcmp(buffer, "srv_only") == 0) whichrrs = HOST_FIND_BY_SRV;
3286 else if (Ustrcmp(buffer, "srv+a") == 0)
66387a73 3287 whichrrs = HOST_FIND_BY_SRV | HOST_FIND_BY_A | HOST_FIND_BY_AAAA;
059ec3d9
PH
3288 else if (Ustrcmp(buffer, "srv+mx") == 0)
3289 whichrrs = HOST_FIND_BY_SRV | HOST_FIND_BY_MX;
3290 else if (Ustrcmp(buffer, "srv+mx+a") == 0)
66387a73 3291 whichrrs = HOST_FIND_BY_SRV | HOST_FIND_BY_MX | HOST_FIND_BY_A | HOST_FIND_BY_AAAA;
8c51eead 3292 else if (Ustrcmp(buffer, "qualify_single") == 0) qualify_single = TRUE;
059ec3d9 3293 else if (Ustrcmp(buffer, "no_qualify_single") == 0) qualify_single = FALSE;
8c51eead 3294 else if (Ustrcmp(buffer, "search_parents") == 0) search_parents = TRUE;
059ec3d9 3295 else if (Ustrcmp(buffer, "no_search_parents") == 0) search_parents = FALSE;
8c51eead
JH
3296 else if (Ustrcmp(buffer, "request_dnssec") == 0) request_dnssec = TRUE;
3297 else if (Ustrcmp(buffer, "no_request_dnssec") == 0) request_dnssec = FALSE;
3298 else if (Ustrcmp(buffer, "require_dnssec") == 0) require_dnssec = TRUE;
f988ce57 3299 else if (Ustrcmp(buffer, "no_require_dnssec") == 0) require_dnssec = FALSE;
e7726cbf 3300 else if (Ustrcmp(buffer, "test_harness") == 0)
8768d548 3301 f.running_in_test_harness = !f.running_in_test_harness;
322050c2 3302 else if (Ustrcmp(buffer, "ipv6") == 0) disable_ipv6 = !disable_ipv6;
e7726cbf
PH
3303 else if (Ustrcmp(buffer, "res_debug") == 0)
3304 {
3305 _res.options ^= RES_DEBUG;
3306 }
059ec3d9
PH
3307 else if (Ustrncmp(buffer, "retrans", 7) == 0)
3308 {
ff790e47 3309 (void)sscanf(CS(buffer+8), "%d", &dns_retrans);
059ec3d9
PH
3310 _res.retrans = dns_retrans;
3311 }
3312 else if (Ustrncmp(buffer, "retry", 5) == 0)
3313 {
ff790e47 3314 (void)sscanf(CS(buffer+6), "%d", &dns_retry);
059ec3d9
PH
3315 _res.retry = dns_retry;
3316 }
059ec3d9
PH
3317 else
3318 {
3319 int flags = whichrrs;
505d976a 3320 dnssec_domains d;
059ec3d9
PH
3321
3322 h.name = buffer;
3323 h.next = NULL;
3324 h.mx = MX_NONE;
3325 h.port = PORT_NONE;
3326 h.status = hstatus_unknown;
3327 h.why = hwhy_unknown;
3328 h.address = NULL;
3329
3330 if (qualify_single) flags |= HOST_FIND_QUALIFY_SINGLE;
3331 if (search_parents) flags |= HOST_FIND_SEARCH_PARENTS;
3332
7cd171b7
JH
3333 d.request = request_dnssec ? &h.name : NULL;
3334 d.require = require_dnssec ? &h.name : NULL;
3335
8c51eead
JH
3336 rc = byname
3337 ? host_find_byname(&h, NULL, flags, &fully_qualified_name, TRUE)
3338 : host_find_bydns(&h, NULL, flags, US"smtp", NULL, NULL,
7cd171b7 3339 &d, &fully_qualified_name, NULL);
059ec3d9 3340
2546388c
JH
3341 switch (rc)
3342 {
3343 case HOST_FIND_FAILED: printf("Failed\n"); break;
3344 case HOST_FIND_AGAIN: printf("Again\n"); break;
3345 case HOST_FIND_SECURITY: printf("Security\n"); break;
3346 case HOST_FOUND_LOCAL: printf("Local\n"); break;
3347 }
059ec3d9
PH
3348 }
3349
3350 printf("\n> ");
3351 }
3352
3353printf("Testing host_aton\n");
3354printf("> ");
3355while (Ufgets(buffer, 256, stdin) != NULL)
3356 {
059ec3d9
PH
3357 int x[4];
3358 int len = Ustrlen(buffer);
3359
3360 while (len > 0 && isspace(buffer[len-1])) len--;
3361 buffer[len] = 0;
3362
3363 if (Ustrcmp(buffer, "q") == 0) break;
3364
3365 len = host_aton(buffer, x);
3366 printf("length = %d ", len);
d7978c0f 3367 for (int i = 0; i < len; i++)
059ec3d9
PH
3368 {
3369 printf("%04x ", (x[i] >> 16) & 0xffff);
3370 printf("%04x ", x[i] & 0xffff);
3371 }
3372 printf("\n> ");
3373 }
3374
3375printf("\n");
3376
3377printf("Testing host_name_lookup\n");
3378printf("> ");
3379while (Ufgets(buffer, 256, stdin) != NULL)
3380 {
3381 int len = Ustrlen(buffer);
3382 while (len > 0 && isspace(buffer[len-1])) len--;
3383 buffer[len] = 0;
3384 if (Ustrcmp(buffer, "q") == 0) break;
3385 sender_host_address = buffer;
3386 sender_host_name = NULL;
3387 sender_host_aliases = NULL;
3388 host_lookup_msg = US"";
3389 host_lookup_failed = FALSE;
3390 if (host_name_lookup() == FAIL) /* Debug causes printing */
3391 printf("Lookup failed:%s\n", host_lookup_msg);
3392 printf("\n> ");
3393 }
3394
3395printf("\n");
3396
3397return 0;
3398}
3399#endif /* STAND_ALONE */
3400
8c51eead
JH
3401/* vi: aw ai sw=2
3402*/
059ec3d9 3403/* End of host.c */