1 /*************************************************
2 * Exim - an Internet mail transport agent *
3 *************************************************/
5 /* Copyright (c) The Exim Maintainers 2020 - 2022 */
6 /* Copyright (c) University of Cambridge 1995 - 2018 */
7 /* See the file NOTICE for conditions of use and distribution. */
8 /* SPDX-License-Identifier: GPL-2.0-or-later */
10 /* Functions for finding hosts, either by gethostbyname(), gethostbyaddr(), or
11 directly via the DNS. When IPv6 is supported, getipnodebyname() and
12 getipnodebyaddr() may be used instead of gethostbyname() and gethostbyaddr(),
13 if the newer functions are available. This module also contains various other
14 functions concerned with hosts and addresses, and a random number function,
15 used for randomizing hosts with equal MXs but available for use in other parts
22 /* Static variable for preserving the list of interface addresses in case it is
23 used more than once. */
25 static ip_address_item *local_interface_data = NULL;
28 #ifdef USE_INET_NTOA_FIX
29 /*************************************************
30 * Replacement for broken inet_ntoa() *
31 *************************************************/
33 /* On IRIX systems, gcc uses a different structure passing convention to the
34 native libraries. This causes inet_ntoa() to always yield 0.0.0.0 or
35 255.255.255.255. To get round this, we provide a private version of the
36 function here. It is used only if USE_INET_NTOA_FIX is set, which should happen
37 only when gcc is in use on an IRIX system. Code send to me by J.T. Breitner,
41 as seen in comp.sys.sgi.admin
43 August 2005: Apparently this is also needed for AIX systems; USE_INET_NTOA_FIX
44 should now be set for them as well.
46 Arguments: sa an in_addr structure
47 Returns: pointer to static text string
51 inet_ntoa(struct in_addr sa)
53 static uschar addr[20];
54 sprintf(addr, "%d.%d.%d.%d",
65 /*************************************************
66 * Random number generator *
67 *************************************************/
69 /* This is a simple pseudo-random number generator. It does not have to be
70 very good for the uses to which it is put. When running the regression tests,
71 start with a fixed seed.
73 If you need better, see vaguely_random_number() which is potentially stronger,
74 if a crypto library is available, but might end up just calling this instead.
77 limit: one more than the largest number required
79 Returns: a pseudo-random number in the range 0 to limit-1
83 random_number(int limit)
88 if (f.running_in_test_harness)
92 int p = (int)getpid();
93 random_seed = (int)time(NULL) ^ ((p << 16) | p);
95 random_seed = 1103515245 * random_seed + 12345;
96 return (unsigned int)(random_seed >> 16) % limit;
99 /*************************************************
100 * Wrappers for logging lookup times *
101 *************************************************/
103 /* When the 'slow_lookup_log' variable is enabled, these wrappers will
104 write to the log file all (potential) dns lookups that take more than
105 slow_lookup_log milliseconds
109 log_long_lookup(const uschar * type, const uschar * data, unsigned long msec)
111 log_write(0, LOG_MAIN, "Long %s lookup for '%s': %lu msec",
116 /* returns the current system epoch time in milliseconds. */
120 struct timeval tmp_time;
121 unsigned long seconds, microseconds;
123 gettimeofday(&tmp_time, NULL);
124 seconds = (unsigned long) tmp_time.tv_sec;
125 microseconds = (unsigned long) tmp_time.tv_usec;
126 return seconds*1000 + microseconds/1000;
131 dns_lookup_timerwrap(dns_answer *dnsa, const uschar *name, int type,
132 const uschar **fully_qualified_name)
135 unsigned long time_msec;
137 if (!slow_lookup_log)
138 return dns_lookup(dnsa, name, type, fully_qualified_name);
140 time_msec = get_time_in_ms();
141 retval = dns_lookup(dnsa, name, type, fully_qualified_name);
142 if ((time_msec = get_time_in_ms() - time_msec) > slow_lookup_log)
143 log_long_lookup(dns_text_type(type), name, time_msec);
148 /*************************************************
149 * Replace gethostbyname() when testing *
150 *************************************************/
152 /* This function is called instead of gethostbyname(), gethostbyname2(), or
153 getipnodebyname() when running in the test harness. . It also
154 recognizes an unqualified "localhost" and forces it to the appropriate loopback
155 address. IP addresses are treated as literals. For other names, it uses the DNS
156 to find the host name. In the test harness, this means it will access only the
160 name the host name or a textual IP address
161 af AF_INET or AF_INET6
162 error_num where to put an error code:
163 HOST_NOT_FOUND/TRY_AGAIN/NO_RECOVERY/NO_DATA
165 Returns: a hostent structure or NULL for an error
168 static struct hostent *
169 host_fake_gethostbyname(const uschar *name, int af, int *error_num)
172 int alen = (af == AF_INET)? sizeof(struct in_addr):sizeof(struct in6_addr);
174 int alen = sizeof(struct in_addr);
178 const uschar *lname = name;
181 struct hostent *yield;
182 dns_answer * dnsa = store_get_dns_answer();
186 debug_printf("using host_fake_gethostbyname for %s (%s)\n", name,
187 af == AF_INET ? "IPv4" : "IPv6");
189 /* Handle unqualified "localhost" */
191 if (Ustrcmp(name, "localhost") == 0)
192 lname = af == AF_INET ? US"127.0.0.1" : US"::1";
194 /* Handle a literal IP address */
196 if ((ipa = string_is_ip_address(lname, NULL)) != 0)
197 if ( ipa == 4 && af == AF_INET
198 || ipa == 6 && af == AF_INET6)
201 yield = store_get(sizeof(struct hostent), GET_UNTAINTED);
202 alist = store_get(2 * sizeof(char *), GET_UNTAINTED);
203 adds = store_get(alen, GET_UNTAINTED);
204 yield->h_name = CS name;
205 yield->h_aliases = NULL;
206 yield->h_addrtype = af;
207 yield->h_length = alen;
208 yield->h_addr_list = CSS alist;
210 for (int n = host_aton(lname, x), i = 0; i < n; i++)
213 *adds++ = (y >> 24) & 255;
214 *adds++ = (y >> 16) & 255;
215 *adds++ = (y >> 8) & 255;
221 /* Wrong kind of literal address */
225 *error_num = HOST_NOT_FOUND;
230 /* Handle a host name */
234 int type = af == AF_INET ? T_A:T_AAAA;
235 int rc = dns_lookup_timerwrap(dnsa, lname, type, NULL);
238 lookup_dnssec_authenticated = NULL;
242 case DNS_SUCCEED: break;
243 case DNS_NOMATCH: *error_num = HOST_NOT_FOUND; yield = NULL; goto out;
244 case DNS_NODATA: *error_num = NO_DATA; yield = NULL; goto out;
245 case DNS_AGAIN: *error_num = TRY_AGAIN; yield = NULL; goto out;
247 case DNS_FAIL: *error_num = NO_RECOVERY; yield = NULL; goto out;
250 for (dns_record * rr = dns_next_rr(dnsa, &dnss, RESET_ANSWERS);
252 rr = dns_next_rr(dnsa, &dnss, RESET_NEXT)) if (rr->type == type)
255 yield = store_get(sizeof(struct hostent), GET_UNTAINTED);
256 alist = store_get((count + 1) * sizeof(char *), GET_UNTAINTED);
257 adds = store_get(count *alen, GET_UNTAINTED);
259 yield->h_name = CS name;
260 yield->h_aliases = NULL;
261 yield->h_addrtype = af;
262 yield->h_length = alen;
263 yield->h_addr_list = CSS alist;
265 for (dns_record * rr = dns_next_rr(dnsa, &dnss, RESET_ANSWERS);
267 rr = dns_next_rr(dnsa, &dnss, RESET_NEXT)) if (rr->type == type)
271 if (!(da = dns_address_from_rr(dnsa, rr))) break;
273 for (int n = host_aton(da->address, x), i = 0; i < n; i++)
276 *adds++ = (y >> 24) & 255;
277 *adds++ = (y >> 16) & 255;
278 *adds++ = (y >> 8) & 255;
287 store_free_dns_answer(dnsa);
293 /*************************************************
294 * Build chain of host items from list *
295 *************************************************/
297 /* This function builds a chain of host items from a textual list of host
298 names. It does not do any lookups. If randomize is true, the chain is build in
299 a randomized order. There may be multiple groups of independently randomized
300 hosts; they are delimited by a host name consisting of just "+".
303 anchor anchor for the chain
305 randomize TRUE for randomizing
311 host_build_hostlist(host_item **anchor, const uschar *list, BOOL randomize)
314 int fake_mx = MX_NONE; /* This value is actually -1 */
318 if (randomize) fake_mx--; /* Start at -2 for randomizing */
322 while ((name = string_nextinlist(&list, &sep, NULL, 0)))
326 if (name[0] == '+' && name[1] == 0) /* "+" delimits a randomized group */
327 { /* ignore if not randomizing */
328 if (randomize) fake_mx--;
332 h = store_get(sizeof(host_item), GET_UNTAINTED);
337 h->sort_key = randomize ? (-fake_mx)*1000 + random_number(1000) : 0;
338 h->status = hstatus_unknown;
339 h->why = hwhy_unknown;
349 host_item *hh = *anchor;
350 if (h->sort_key < hh->sort_key)
357 while (hh->next && h->sort_key >= hh->next->sort_key)
367 /*************************************************
368 * Get port from a host item's name *
369 *************************************************/
371 /* This function is called when finding the IP address for a host that is in a
372 list of hosts explicitly configured, such as in the manualroute router, or in a
373 fallback hosts list. We see if there is a port specification at the end of the
374 host name, and if so, remove it. A minimum length of 3 is required for the
375 original name; nothing shorter is recognized as having a port.
377 We test for a name ending with a sequence of digits; if preceded by colon we
378 have a port if the character before the colon is ] and the name starts with [
379 or if there are no other colons in the name (i.e. it's not an IPv6 address).
381 Arguments: pointer to the host item
382 Returns: a port number or PORT_NONE
386 host_item_get_port(host_item *h)
390 int len = Ustrlen(h->name);
392 if (len < 3 || (p = h->name + len - 1, !isdigit(*p))) return PORT_NONE;
394 /* Extract potential port number */
399 while (p > h->name + 1 && isdigit(*p))
401 port += (*p-- - '0') * x;
405 /* The smallest value of p at this point is h->name + 1. */
407 if (*p != ':') return PORT_NONE;
409 if (p[-1] == ']' && h->name[0] == '[')
410 h->name = string_copyn(h->name + 1, p - h->name - 2);
411 else if (Ustrchr(h->name, ':') == p)
412 h->name = string_copyn(h->name, p - h->name);
413 else return PORT_NONE;
415 DEBUG(D_route|D_host_lookup) debug_printf("host=%s port=%d\n", h->name, port);
421 #ifndef STAND_ALONE /* Omit when standalone testing */
423 /*************************************************
424 * Build sender_fullhost and sender_rcvhost *
425 *************************************************/
427 /* This function is called when sender_host_name and/or sender_helo_name
428 have been set. Or might have been set - for a local message read off the spool
429 they won't be. In that case, do nothing. Otherwise, set up the fullhost string
432 (a) No sender_host_name or sender_helo_name: "[ip address]"
433 (b) Just sender_host_name: "host_name [ip address]"
434 (c) Just sender_helo_name: "(helo_name) [ip address]" unless helo is IP
435 in which case: "[ip address}"
436 (d) The two are identical: "host_name [ip address]" includes helo = IP
437 (e) The two are different: "host_name (helo_name) [ip address]"
439 If log_incoming_port is set, the sending host's port number is added to the IP
442 This function also builds sender_rcvhost for use in Received: lines, whose
443 syntax is a bit different. This value also includes the RFC 1413 identity.
444 There wouldn't be two different variables if I had got all this right in the
447 Because this data may survive over more than one incoming SMTP message, it has
448 to be in permanent store. However, STARTTLS has to be forgotten and redone
449 on a multi-message conn, so this will be called once per message then. Hence
450 we use malloc, so we can free.
457 host_build_sender_fullhost(void)
459 BOOL show_helo = TRUE;
460 uschar * address, * fullhost, * rcvhost;
464 if (!sender_host_address) return;
466 reset_point = store_mark();
468 /* Set up address, with or without the port. After discussion, it seems that
469 the only format that doesn't cause trouble is [aaaa]:pppp. However, we can't
470 use this directly as the first item for Received: because it ain't an RFC 2822
473 address = string_sprintf("[%s]:%d", sender_host_address, sender_host_port);
474 if (!LOGGING(incoming_port) || sender_host_port <= 0)
475 *(Ustrrchr(address, ':')) = 0;
477 /* If there's no EHLO/HELO data, we can't show it. */
479 if (!sender_helo_name) show_helo = FALSE;
481 /* If HELO/EHLO was followed by an IP literal, it's messy because of two
482 features of IPv6. Firstly, there's the "IPv6:" prefix (Exim is liberal and
483 doesn't require this, for historical reasons). Secondly, IPv6 addresses may not
484 be given in canonical form, so we have to canonicalize them before comparing. As
485 it happens, the code works for both IPv4 and IPv6. */
487 else if (sender_helo_name[0] == '[' &&
488 sender_helo_name[(len=Ustrlen(sender_helo_name))-1] == ']')
493 if (strncmpic(sender_helo_name + 1, US"IPv6:", 5) == 0) offset += 5;
494 if (strncmpic(sender_helo_name + 1, US"IPv4:", 5) == 0) offset += 5;
496 helo_ip = string_copyn(sender_helo_name + offset, len - offset - 1);
498 if (string_is_ip_address(helo_ip, NULL) != 0)
502 uschar ipx[48], ipy[48]; /* large enough for full IPv6 */
504 sizex = host_aton(helo_ip, x);
505 sizey = host_aton(sender_host_address, y);
507 (void)host_nmtoa(sizex, x, -1, ipx, ':');
508 (void)host_nmtoa(sizey, y, -1, ipy, ':');
510 if (strcmpic(ipx, ipy) == 0) show_helo = FALSE;
514 /* Host name is not verified */
516 if (!sender_host_name)
518 uschar *portptr = Ustrstr(address, "]:");
520 int adlen; /* Sun compiler doesn't like ++ in initializers */
522 adlen = portptr ? (++portptr - address) : Ustrlen(address);
523 fullhost = sender_helo_name
524 ? string_sprintf("(%s) %s", sender_helo_name, address)
527 g = string_catn(NULL, address, adlen);
529 if (sender_ident || show_helo || portptr)
532 g = string_catn(g, US" (", 2);
536 g = string_append(g, 2, US"port=", portptr + 1);
539 g = string_append(g, 2,
540 firstptr == g->ptr ? US"helo=" : US" helo=", sender_helo_name);
543 g = string_append(g, 2,
544 firstptr == g->ptr ? US"ident=" : US" ident=", sender_ident);
546 g = string_catn(g, US")", 1);
549 rcvhost = string_from_gstring(g);
552 /* Host name is known and verified. Unless we've already found that the HELO
553 data matches the IP address, compare it with the name. */
557 if (show_helo && strcmpic(sender_host_name, sender_helo_name) == 0)
562 fullhost = string_sprintf("%s (%s) %s", sender_host_name,
563 sender_helo_name, address);
564 rcvhost = sender_ident
565 ? string_sprintf("%s\n\t(%s helo=%s ident=%s)", sender_host_name,
566 address, sender_helo_name, sender_ident)
567 : string_sprintf("%s (%s helo=%s)", sender_host_name,
568 address, sender_helo_name);
572 fullhost = string_sprintf("%s %s", sender_host_name, address);
573 rcvhost = sender_ident
574 ? string_sprintf("%s (%s ident=%s)", sender_host_name, address,
576 : string_sprintf("%s (%s)", sender_host_name, address);
580 sender_fullhost = string_copy_perm(fullhost, TRUE);
581 sender_rcvhost = string_copy_perm(rcvhost, TRUE);
583 store_reset(reset_point);
585 DEBUG(D_host_lookup) debug_printf("sender_fullhost = %s\n", sender_fullhost);
586 DEBUG(D_host_lookup) debug_printf("sender_rcvhost = %s\n", sender_rcvhost);
591 /*************************************************
592 * Build host+ident message *
593 *************************************************/
595 /* Used when logging rejections and various ACL and SMTP incidents. The text
596 return depends on whether sender_fullhost and sender_ident are set or not:
598 no ident, no host => U=unknown
599 no ident, host set => H=sender_fullhost
600 ident set, no host => U=ident
601 ident set, host set => H=sender_fullhost U=ident
603 Use taint-unchecked routines on the assumption we'll never expand the results.
606 useflag TRUE if first item to be flagged (H= or U=); if there are two
607 items, the second is always flagged
609 Returns: pointer to a string in big_buffer
613 host_and_ident(BOOL useflag)
615 if (!sender_fullhost)
616 string_format_nt(big_buffer, big_buffer_size, "%s%s", useflag ? "U=" : "",
617 sender_ident ? sender_ident : US"unknown");
620 uschar * flag = useflag ? US"H=" : US"";
621 uschar * iface = US"";
622 if (LOGGING(incoming_interface) && interface_address)
623 iface = string_sprintf(" I=[%s]:%d", interface_address, interface_port);
625 string_format_nt(big_buffer, big_buffer_size, "%s%s%s U=%s",
626 flag, sender_fullhost, iface, sender_ident);
628 string_format_nt(big_buffer, big_buffer_size, "%s%s%s",
629 flag, sender_fullhost, iface);
634 #endif /* STAND_ALONE */
639 /*************************************************
640 * Build list of local interfaces *
641 *************************************************/
643 /* This function interprets the contents of the local_interfaces or
644 extra_local_interfaces options, and creates an ip_address_item block for each
645 item on the list. There is no special interpretation of any IP addresses; in
646 particular, 0.0.0.0 and ::0 are returned without modification. If any address
647 includes a port, it is set in the block. Otherwise the port value is set to
652 name the name of the option being expanded
654 Returns: a chain of ip_address_items, each containing to a textual
655 version of an IP address, and a port number (host order) or
656 zero if no port was given with the address
660 host_build_ifacelist(const uschar *list, uschar *name)
664 ip_address_item * yield = NULL, * last = NULL, * next;
666 while ((s = string_nextinlist(&list, &sep, NULL, 0)))
669 int port = host_address_extract_port(s); /* Leaves just the IP address */
671 if (!(ipv = string_is_ip_address(s, NULL)))
672 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Malformed IP address \"%s\" in %s",
675 /* Skip IPv6 addresses if IPv6 is disabled. */
677 if (disable_ipv6 && ipv == 6) continue;
679 /* This use of strcpy() is OK because we have checked that s is a valid IP
680 address above. The field in the ip_address_item is large enough to hold an
683 next = store_get(sizeof(ip_address_item), list);
685 Ustrcpy(next->address, s);
687 next->v6_include_v4 = FALSE;
706 /*************************************************
707 * Find addresses on local interfaces *
708 *************************************************/
710 /* This function finds the addresses of local IP interfaces. These are used
711 when testing for routing to the local host. As the function may be called more
712 than once, the list is preserved in permanent store, pointed to by a static
713 variable, to save doing the work more than once per process.
715 The generic list of interfaces is obtained by calling host_build_ifacelist()
716 for local_interfaces and extra_local_interfaces. This list scanned to remove
717 duplicates (which may exist with different ports - not relevant here). If
718 either of the wildcard IP addresses (0.0.0.0 and ::0) are encountered, they are
719 replaced by the appropriate (IPv4 or IPv6) list of actual local interfaces,
720 obtained from os_find_running_interfaces().
723 Returns: a chain of ip_address_items, each containing to a textual
724 version of an IP address; the port numbers are not relevant
728 /* First, a local subfunction to add an interface to a list in permanent store,
729 but only if there isn't a previous copy of that address on the list. */
731 static ip_address_item *
732 add_unique_interface(ip_address_item *list, ip_address_item *ipa)
734 ip_address_item *ipa2;
735 for (ipa2 = list; ipa2; ipa2 = ipa2->next)
736 if (Ustrcmp(ipa2->address, ipa->address) == 0) return list;
737 ipa2 = store_get_perm(sizeof(ip_address_item), FALSE);
744 /* This is the globally visible function */
747 host_find_interfaces(void)
749 ip_address_item *running_interfaces = NULL;
751 if (!local_interface_data)
753 void *reset_item = store_mark();
754 ip_address_item *dlist = host_build_ifacelist(CUS local_interfaces,
755 US"local_interfaces");
756 ip_address_item *xlist = host_build_ifacelist(CUS extra_local_interfaces,
757 US"extra_local_interfaces");
758 ip_address_item *ipa;
760 if (!dlist) dlist = xlist;
763 for (ipa = dlist; ipa->next; ipa = ipa->next) ;
767 for (ipa = dlist; ipa; ipa = ipa->next)
769 if (Ustrcmp(ipa->address, "0.0.0.0") == 0 ||
770 Ustrcmp(ipa->address, "::0") == 0)
772 BOOL ipv6 = ipa->address[0] == ':';
773 if (!running_interfaces)
774 running_interfaces = os_find_running_interfaces();
775 for (ip_address_item * ipa2 = running_interfaces; ipa2; ipa2 = ipa2->next)
776 if ((Ustrchr(ipa2->address, ':') != NULL) == ipv6)
777 local_interface_data = add_unique_interface(local_interface_data,
782 local_interface_data = add_unique_interface(local_interface_data, ipa);
785 debug_printf("Configured local interface: address=%s", ipa->address);
786 if (ipa->port != 0) debug_printf(" port=%d", ipa->port);
791 store_reset(reset_item);
794 return local_interface_data;
801 /*************************************************
802 * Convert network IP address to text *
803 *************************************************/
805 /* Given an IPv4 or IPv6 address in binary, convert it to a text
806 string and return the result in a piece of new store. The address can
807 either be given directly, or passed over in a sockaddr structure. Note
808 that this isn't the converse of host_aton() because of byte ordering
809 differences. See host_nmtoa() below.
812 type if < 0 then arg points to a sockaddr, else
813 either AF_INET or AF_INET6
814 arg points to a sockaddr if type is < 0, or
815 points to an IPv4 address (32 bits), or
816 points to an IPv6 address (128 bits),
817 in both cases, in network byte order
818 buffer if NULL, the result is returned in gotten store;
819 else points to a buffer to hold the answer
820 portptr points to where to put the port number, if non NULL; only
823 Returns: pointer to character string
827 host_ntoa(int type, const void * arg, uschar * buffer, int * portptr)
831 /* The new world. It is annoying that we have to fish out the address from
832 different places in the block, depending on what kind of address it is. It
833 is also a pain that inet_ntop() returns a const uschar *, whereas the IPv4
834 function inet_ntoa() returns just uschar *, and some picky compilers insist
835 on warning if one assigns a const uschar * to a uschar *. Hence the casts. */
838 uschar addr_buffer[46];
841 int family = ((struct sockaddr *)arg)->sa_family;
842 if (family == AF_INET6)
844 struct sockaddr_in6 *sk = (struct sockaddr_in6 *)arg;
845 yield = US inet_ntop(family, &(sk->sin6_addr), CS addr_buffer,
846 sizeof(addr_buffer));
847 if (portptr) *portptr = ntohs(sk->sin6_port);
851 struct sockaddr_in *sk = (struct sockaddr_in *)arg;
852 yield = US inet_ntop(family, &(sk->sin_addr), CS addr_buffer,
853 sizeof(addr_buffer));
854 if (portptr) *portptr = ntohs(sk->sin_port);
859 yield = US inet_ntop(type, arg, CS addr_buffer, sizeof(addr_buffer));
862 /* If the result is a mapped IPv4 address, show it in V4 format. */
864 if (Ustrncmp(yield, "::ffff:", 7) == 0) yield += 7;
866 #else /* HAVE_IPV6 */
872 yield = US inet_ntoa(((struct sockaddr_in *)arg)->sin_addr);
873 if (portptr) *portptr = ntohs(((struct sockaddr_in *)arg)->sin_port);
876 yield = US inet_ntoa(*((struct in_addr *)arg));
879 /* If there is no buffer, put the string into some new store. */
881 if (!buffer) buffer = store_get(46, GET_UNTAINTED);
883 /* Callers of this function with a non-NULL buffer must ensure that it is
884 large enough to hold an IPv6 address, namely, at least 46 bytes. That's what
885 makes this use of strcpy() OK.
886 If the library returned apparently an apparently tainted string, clean it;
887 we trust IP addresses. */
889 string_format_nt(buffer, 46, "%s", yield);
896 /*************************************************
897 * Convert address text to binary *
898 *************************************************/
900 /* Given the textual form of an IP address, convert it to binary in an
901 array of ints. IPv4 addresses occupy one int; IPv6 addresses occupy 4 ints.
902 The result has the first byte in the most significant byte of the first int. In
903 other words, the result is not in network byte order, but in host byte order.
904 As a result, this is not the converse of host_ntoa(), which expects network
905 byte order. See host_nmtoa() below.
908 address points to the textual address, checked for syntax
909 bin points to an array of 4 ints
911 Returns: the number of ints used
915 host_aton(const uschar * address, int * bin)
920 /* Handle IPv6 address, which may end with an IPv4 address. It may also end
921 with a "scope", introduced by a percent sign. This code is NOT enclosed in #if
922 HAVE_IPV6 in order that IPv6 addresses are recognized even if IPv6 is not
925 if (Ustrchr(address, ':') != NULL)
927 const uschar * p = address;
928 const uschar * component[8];
929 BOOL ipv4_ends = FALSE;
930 int ci = 0, nulloffset = 0, v6count = 8, i;
932 /* If the address starts with a colon, it will start with two colons.
933 Just lose the first one, which will leave a null first component. */
937 /* Split the address into components separated by colons. The input address
938 is supposed to be checked for syntax. There was a case where this was
939 overlooked; to guard against that happening again, check here and crash if
940 there are too many components. */
942 while (*p && *p != '%')
944 int len = Ustrcspn(p, ":%");
945 if (len == 0) nulloffset = ci;
946 if (ci > 7) log_write(0, LOG_MAIN|LOG_PANIC_DIE,
947 "Internal error: invalid IPv6 address \"%s\" passed to host_aton()",
954 /* If the final component contains a dot, it is a trailing v4 address.
955 As the syntax is known to be checked, just set up for a trailing
956 v4 address and restrict the v6 part to 6 components. */
958 if (Ustrchr(component[ci-1], '.') != NULL)
960 address = component[--ci];
966 /* If there are fewer than 6 or 8 components, we have to insert some
967 more empty ones in the middle. */
971 int insert_count = v6count - ci;
972 for (i = v6count-1; i > nulloffset + insert_count; i--)
973 component[i] = component[i - insert_count];
974 while (i > nulloffset) component[i--] = US"";
977 /* Now turn the components into binary in pairs and bung them
978 into the vector of ints. */
980 for (i = 0; i < v6count; i += 2)
981 bin[i/2] = (Ustrtol(component[i], NULL, 16) << 16) +
982 Ustrtol(component[i+1], NULL, 16);
984 /* If there was no terminating v4 component, we are done. */
986 if (!ipv4_ends) return 4;
989 /* Handle IPv4 address */
991 (void)sscanf(CS address, "%d.%d.%d.%d", x, x+1, x+2, x+3);
992 bin[v4offset] = ((uint)x[0] << 24) + (x[1] << 16) + (x[2] << 8) + x[3];
997 /*************************************************
998 * Apply mask to an IP address *
999 *************************************************/
1001 /* Mask an address held in 1 or 4 ints, with the ms bit in the ms bit of the
1005 count the number of ints
1006 binary points to the ints to be masked
1007 mask the count of ms bits to leave, or -1 if no masking
1013 host_mask(int count, int *binary, int mask)
1015 if (mask < 0) mask = 99999;
1016 for (int i = 0; i < count; i++)
1019 if (mask == 0) wordmask = 0;
1022 wordmask = (uint)(-1) << (32 - mask);
1030 binary[i] &= wordmask;
1037 /*************************************************
1038 * Convert masked IP address in ints to text *
1039 *************************************************/
1041 /* We can't use host_ntoa() because it assumes the binary values are in network
1042 byte order, and these are the result of host_aton(), which puts them in ints in
1043 host byte order. Also, we really want IPv6 addresses to be in a canonical
1044 format, so we output them with no abbreviation. In a number of cases we can't
1045 use the normal colon separator in them because it terminates keys in lsearch
1046 files, so we want to use dot instead. There's an argument that specifies what
1047 to use for IPv6 addresses.
1050 count 1 or 4 (number of ints)
1051 binary points to the ints
1052 mask mask value; if < 0 don't add to result
1053 buffer big enough to hold the result
1054 sep component separator character for IPv6 addresses
1056 Returns: the number of characters placed in buffer, not counting
1061 host_nmtoa(int count, int *binary, int mask, uschar *buffer, int sep)
1064 uschar *tt = buffer;
1069 for (int i = 24; i >= 0; i -= 8)
1070 tt += sprintf(CS tt, "%d.", (j >> i) & 255);
1073 for (int i = 0; i < 4; i++)
1076 tt += sprintf(CS tt, "%04x%c%04x%c", (j >> 16) & 0xffff, sep, j & 0xffff, sep);
1079 tt--; /* lose final separator */
1084 tt += sprintf(CS tt, "/%d", mask);
1090 /* Like host_nmtoa() but: ipv6-only, canonical output, no mask
1093 binary points to the ints
1094 buffer big enough to hold the result
1096 Returns: the number of characters placed in buffer, not counting
1101 ipv6_nmtoa(int * binary, uschar * buffer)
1104 uschar * c = buffer;
1105 uschar * d = NULL; /* shut insufficiently "clever" compiler up */
1107 for (i = 0; i < 4; i++)
1108 { /* expand to text */
1110 c += sprintf(CS c, "%x:%x:", (j >> 16) & 0xffff, j & 0xffff);
1113 for (c = buffer, k = -1, i = 0; i < 8; i++)
1114 { /* find longest 0-group sequence */
1115 if (*c == '0') /* must be "0:" */
1119 while (c[2] == '0') i++, c += 2;
1122 k = i-j; /* length of sequence */
1123 d = s; /* start of sequence */
1126 while (*++c != ':') ;
1130 *--c = '\0'; /* drop trailing colon */
1132 /* debug_printf("%s: D k %d <%s> <%s>\n", __FUNCTION__, k, buffer, buffer + 2*(k+1)); */
1136 if (d == buffer) c--; /* need extra colon */
1137 *d++ = ':'; /* 1st 0 */
1138 while ((*d++ = *c++)) ;
1148 /*************************************************
1149 * Check port for tls_on_connect *
1150 *************************************************/
1152 /* This function checks whether a given incoming port is configured for tls-
1153 on-connect. It is called from the daemon and from inetd handling. If the global
1154 option tls_on_connect is already set, all ports operate this way. Otherwise, we
1155 check the tls_on_connect_ports option for a list of ports.
1157 Argument: a port number
1158 Returns: TRUE or FALSE
1162 host_is_tls_on_connect_port(int port)
1165 const uschar * list = tls_in.on_connect_ports;
1167 if (tls_in.on_connect) return TRUE;
1169 for (uschar * s, * end; s = string_nextinlist(&list, &sep, NULL, 0); )
1170 if (Ustrtol(s, &end, 10) == port)
1178 /*************************************************
1179 * Check whether host is in a network *
1180 *************************************************/
1182 /* This function checks whether a given IP address matches a pattern that
1183 represents either a single host, or a network (using CIDR notation). The caller
1184 of this function must check the syntax of the arguments before calling it.
1187 host string representation of the ip-address to check
1188 net string representation of the network, with optional CIDR mask
1189 maskoffset offset to the / that introduces the mask in the key
1190 zero if there is no mask
1193 TRUE the host is inside the network
1194 FALSE the host is NOT inside the network
1198 host_is_in_net(const uschar *host, const uschar *net, int maskoffset)
1203 int size = host_aton(net, address);
1206 /* No mask => all bits to be checked */
1208 if (maskoffset == 0) mlen = 99999; /* Big number */
1209 else mlen = Uatoi(net + maskoffset + 1);
1211 /* Convert the incoming address to binary. */
1213 insize = host_aton(host, incoming);
1215 /* Convert IPv4 addresses given in IPv6 compatible mode, which represent
1216 connections from IPv4 hosts to IPv6 hosts, that is, addresses of the form
1217 ::ffff:<v4address>, to IPv4 format. */
1219 if (insize == 4 && incoming[0] == 0 && incoming[1] == 0 &&
1220 incoming[2] == 0xffff)
1223 incoming[0] = incoming[3];
1226 /* No match if the sizes don't agree. */
1228 if (insize != size) return FALSE;
1230 /* Else do the masked comparison. */
1232 for (int i = 0; i < size; i++)
1235 if (mlen == 0) mask = 0;
1238 mask = (uint)(-1) << (32 - mlen);
1246 if ((incoming[i] & mask) != (address[i] & mask)) return FALSE;
1254 /*************************************************
1255 * Scan host list for local hosts *
1256 *************************************************/
1258 /* Scan through a chain of addresses and check whether any of them is the
1259 address of an interface on the local machine. If so, remove that address and
1260 any previous ones with the same MX value, and all subsequent ones (which will
1261 have greater or equal MX values) from the chain. Note: marking them as unusable
1262 is NOT the right thing to do because it causes the hosts not to be used for
1263 other domains, for which they may well be correct.
1265 The hosts may be part of a longer chain; we only process those between the
1266 initial pointer and the "last" pointer.
1268 There is also a list of "pseudo-local" host names which are checked against the
1269 host names. Any match causes that host item to be treated the same as one which
1270 matches a local IP address.
1272 If the very first host is a local host, then all MX records had a precedence
1273 greater than or equal to that of the local host. Either there's a problem in
1274 the DNS, or an apparently remote name turned out to be an abbreviation for the
1275 local host. Give a specific return code, and let the caller decide what to do.
1276 Otherwise, give a success code if at least one host address has been found.
1279 host pointer to the first host in the chain
1280 lastptr pointer to pointer to the last host in the chain (may be updated)
1281 removed if not NULL, set TRUE if some local addresses were removed
1285 HOST_FOUND if there is at least one host with an IP address on the chain
1286 and an MX value less than any MX value associated with the
1288 HOST_FOUND_LOCAL if a local host is among the lowest-numbered MX hosts; when
1289 the host addresses were obtained from A records or
1290 gethostbyname(), the MX values are set to -1.
1291 HOST_FIND_FAILED if no valid hosts with set IP addresses were found
1295 host_scan_for_local_hosts(host_item *host, host_item **lastptr, BOOL *removed)
1297 int yield = HOST_FIND_FAILED;
1298 host_item *last = *lastptr;
1299 host_item *prev = NULL;
1302 if (removed != NULL) *removed = FALSE;
1304 if (local_interface_data == NULL) local_interface_data = host_find_interfaces();
1306 for (h = host; h != last->next; h = h->next)
1309 if (hosts_treat_as_local != NULL)
1312 const uschar *save = deliver_domain;
1313 deliver_domain = h->name; /* set $domain */
1314 rc = match_isinlist(string_copylc(h->name), CUSS &hosts_treat_as_local, 0,
1315 &domainlist_anchor, NULL, MCL_DOMAIN, TRUE, NULL);
1316 deliver_domain = save;
1317 if (rc == OK) goto FOUND_LOCAL;
1321 /* It seems that on many operating systems, 0.0.0.0 is treated as a synonym
1322 for 127.0.0.1 and refers to the local host. We therefore force it always to
1323 be treated as local. */
1325 if (h->address != NULL)
1327 if (Ustrcmp(h->address, "0.0.0.0") == 0) goto FOUND_LOCAL;
1328 for (ip_address_item * ip = local_interface_data; ip; ip = ip->next)
1329 if (Ustrcmp(h->address, ip->address) == 0) goto FOUND_LOCAL;
1330 yield = HOST_FOUND; /* At least one remote address has been found */
1333 /* Update prev to point to the last host item before any that have
1334 the same MX value as the one we have just considered. */
1336 if (h->next == NULL || h->next->mx != h->mx) prev = h;
1339 return yield; /* No local hosts found: return HOST_FOUND or HOST_FIND_FAILED */
1341 /* A host whose IP address matches a local IP address, or whose name matches
1342 something in hosts_treat_as_local has been found. */
1348 HDEBUG(D_host_lookup) debug_printf((h->mx >= 0)?
1349 "local host has lowest MX\n" :
1350 "local host found for non-MX address\n");
1351 return HOST_FOUND_LOCAL;
1354 HDEBUG(D_host_lookup)
1356 debug_printf("local host in host list - removed hosts:\n");
1357 for (h = prev->next; h != last->next; h = h->next)
1358 debug_printf(" %s %s %d\n", h->name, h->address, h->mx);
1361 if (removed != NULL) *removed = TRUE;
1362 prev->next = last->next;
1370 /*************************************************
1371 * Remove duplicate IPs in host list *
1372 *************************************************/
1374 /* You would think that administrators could set up their DNS records so that
1375 one ended up with a list of unique IP addresses after looking up A or MX
1376 records, but apparently duplication is common. So we scan such lists and
1377 remove the later duplicates. Note that we may get lists in which some host
1378 addresses are not set.
1381 host pointer to the first host in the chain
1382 lastptr pointer to pointer to the last host in the chain (may be updated)
1388 host_remove_duplicates(host_item *host, host_item **lastptr)
1390 while (host != *lastptr)
1392 if (host->address != NULL)
1394 host_item *h = host;
1395 while (h != *lastptr)
1397 if (h->next->address != NULL &&
1398 Ustrcmp(h->next->address, host->address) == 0)
1400 DEBUG(D_host_lookup) debug_printf("duplicate IP address %s (MX=%d) "
1401 "removed\n", host->address, h->next->mx);
1402 if (h->next == *lastptr) *lastptr = h;
1403 h->next = h->next->next;
1408 /* If the last item was removed, host may have become == *lastptr */
1409 if (host != *lastptr) host = host->next;
1416 /*************************************************
1417 * Find sender host name by gethostbyaddr() *
1418 *************************************************/
1420 /* This used to be the only way it was done, but it turns out that not all
1421 systems give aliases for calls to gethostbyaddr() - or one of the modern
1422 equivalents like getipnodebyaddr(). Fortunately, multiple PTR records are rare,
1423 but they can still exist. This function is now used only when a DNS lookup of
1424 the IP address fails, in order to give access to /etc/hosts.
1427 Returns: OK, DEFER, FAIL
1431 host_name_lookup_byaddr(void)
1433 struct hostent * hosts;
1434 struct in_addr addr;
1435 unsigned long time_msec = 0; /* init to quieten dumb static analysis */
1437 if (slow_lookup_log) time_msec = get_time_in_ms();
1439 /* Lookup on IPv6 system */
1442 if (Ustrchr(sender_host_address, ':') != NULL)
1444 struct in6_addr addr6;
1445 if (inet_pton(AF_INET6, CS sender_host_address, &addr6) != 1)
1446 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "unable to parse \"%s\" as an "
1447 "IPv6 address", sender_host_address);
1448 #if HAVE_GETIPNODEBYADDR
1449 hosts = getipnodebyaddr(CS &addr6, sizeof(addr6), AF_INET6, &h_errno);
1451 hosts = gethostbyaddr(CS &addr6, sizeof(addr6), AF_INET6);
1456 if (inet_pton(AF_INET, CS sender_host_address, &addr) != 1)
1457 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "unable to parse \"%s\" as an "
1458 "IPv4 address", sender_host_address);
1459 #if HAVE_GETIPNODEBYADDR
1460 hosts = getipnodebyaddr(CS &addr, sizeof(addr), AF_INET, &h_errno);
1462 hosts = gethostbyaddr(CS &addr, sizeof(addr), AF_INET);
1466 /* Do lookup on IPv4 system */
1469 addr.s_addr = (S_ADDR_TYPE)inet_addr(CS sender_host_address);
1470 hosts = gethostbyaddr(CS(&addr), sizeof(addr), AF_INET);
1473 if ( slow_lookup_log
1474 && (time_msec = get_time_in_ms() - time_msec) > slow_lookup_log
1476 log_long_lookup(US"gethostbyaddr", sender_host_address, time_msec);
1478 /* Failed to look up the host. */
1482 HDEBUG(D_host_lookup) debug_printf("IP address lookup failed: h_errno=%d\n",
1484 return (h_errno == TRY_AGAIN || h_errno == NO_RECOVERY) ? DEFER : FAIL;
1487 /* It seems there are some records in the DNS that yield an empty name. We
1488 treat this as non-existent. In some operating systems, this is returned as an
1489 empty string; in others as a single dot. */
1491 if (!hosts->h_name || !hosts->h_name[0] || hosts->h_name[0] == '.')
1493 HDEBUG(D_host_lookup) debug_printf("IP address lookup yielded an empty name: "
1494 "treated as non-existent host name\n");
1498 /* Copy and lowercase the name, which is in static storage in many systems.
1499 Put it in permanent memory. */
1502 int old_pool = store_pool;
1503 store_pool = POOL_TAINT_PERM; /* names are tainted */
1505 sender_host_name = string_copylc(US hosts->h_name);
1507 /* If the host has aliases, build a copy of the alias list */
1509 if (hosts->h_aliases)
1511 int count = 1; /* need 1 more for terminating NULL */
1514 for (uschar ** aliases = USS hosts->h_aliases; *aliases; aliases++) count++;
1515 store_pool = POOL_PERM;
1516 ptr = sender_host_aliases = store_get(count * sizeof(uschar *), GET_UNTAINTED);
1517 store_pool = POOL_TAINT_PERM;
1519 for (uschar ** aliases = USS hosts->h_aliases; *aliases; aliases++)
1520 *ptr++ = string_copylc(*aliases);
1523 store_pool = old_pool;
1531 /*************************************************
1532 * Find host name for incoming call *
1533 *************************************************/
1535 /* Put the name in permanent store, pointed to by sender_host_name. We also set
1536 up a list of alias names, pointed to by sender_host_alias. The list is
1537 NULL-terminated. The incoming address is in sender_host_address, either in
1538 dotted-quad form for IPv4 or in colon-separated form for IPv6.
1540 This function does a thorough check that the names it finds point back to the
1541 incoming IP address. Any that do not are discarded. Note that this is relied on
1542 by the ACL reverse_host_lookup check.
1544 On some systems, get{host,ipnode}byaddr() appears to do this internally, but
1545 this it not universally true. Also, for release 4.30, this function was changed
1546 to do a direct DNS lookup first, by default[1], because it turns out that that
1547 is the only guaranteed way to find all the aliases on some systems. My
1548 experiments indicate that Solaris gethostbyaddr() gives the aliases for but
1551 [1] The actual order is controlled by the host_lookup_order option.
1554 Returns: OK on success, the answer being placed in the global variable
1555 sender_host_name, with any aliases in a list hung off
1557 FAIL if no host name can be found
1558 DEFER if a temporary error was encountered
1560 The variable host_lookup_msg is set to an empty string on success, or to a
1561 reason for the failure otherwise, in a form suitable for tagging onto an error
1562 message, and also host_lookup_failed is set TRUE if the lookup failed. If there
1563 was a defer, host_lookup_deferred is set TRUE.
1565 Any dynamically constructed string for host_lookup_msg must be in permanent
1566 store, because it might be used for several incoming messages on the same SMTP
1570 host_name_lookup(void)
1574 uschar *save_hostname;
1577 const uschar *list = host_lookup_order;
1578 dns_answer * dnsa = store_get_dns_answer();
1581 sender_host_dnssec = host_lookup_deferred = host_lookup_failed = FALSE;
1583 HDEBUG(D_host_lookup)
1584 debug_printf("looking up host name for %s\n", sender_host_address);
1586 /* For testing the case when a lookup does not complete, we have a special
1587 reserved IP address. */
1589 if (f.running_in_test_harness &&
1590 Ustrcmp(sender_host_address, "99.99.99.99") == 0)
1592 HDEBUG(D_host_lookup)
1593 debug_printf("Test harness: host name lookup returns DEFER\n");
1594 host_lookup_deferred = TRUE;
1598 /* Do lookups directly in the DNS or via gethostbyaddr() (or equivalent), in
1599 the order specified by the host_lookup_order option. */
1601 while ((ordername = string_nextinlist(&list, &sep, NULL, 0)))
1603 if (strcmpic(ordername, US"bydns") == 0)
1605 uschar * name = dns_build_reverse(sender_host_address);
1607 dns_init(FALSE, FALSE, FALSE); /* dnssec ctrl by dns_dnssec_ok glbl */
1608 rc = dns_lookup_timerwrap(dnsa, name, T_PTR, NULL);
1610 /* The first record we come across is used for the name; others are
1611 considered to be aliases. We have to scan twice, in order to find out the
1612 number of aliases. However, if all the names are empty, we will behave as
1613 if failure. (PTR records that yield empty names have been encountered in
1616 if (rc == DNS_SUCCEED)
1618 uschar **aptr = NULL;
1620 int count = 1; /* need 1 more for terminating NULL */
1621 int old_pool = store_pool;
1623 sender_host_dnssec = dns_is_secure(dnsa);
1625 debug_printf("Reverse DNS security status: %s\n",
1626 sender_host_dnssec ? "DNSSEC verified (AD)" : "unverified");
1628 store_pool = POOL_PERM; /* Save names in permanent storage */
1630 for (dns_record * rr = dns_next_rr(dnsa, &dnss, RESET_ANSWERS);
1632 rr = dns_next_rr(dnsa, &dnss, RESET_NEXT)) if (rr->type == T_PTR)
1635 /* Get store for the list of aliases. For compatibility with
1636 gethostbyaddr, we make an empty list if there are none. */
1638 aptr = sender_host_aliases = store_get(count * sizeof(uschar *), GET_UNTAINTED);
1640 /* Re-scan and extract the names */
1642 for (dns_record * rr = dns_next_rr(dnsa, &dnss, RESET_ANSWERS);
1644 rr = dns_next_rr(dnsa, &dnss, RESET_NEXT)) if (rr->type == T_PTR)
1646 uschar * s = store_get(ssize, GET_TAINTED); /* names are tainted */
1649 /* If an overlong response was received, the data will have been
1650 truncated and dn_expand may fail. */
1652 if (dn_expand(dnsa->answer, dnsa->answer + dnsa->answerlen,
1653 US (rr->data), (DN_EXPAND_ARG4_TYPE)(s), ssize) < 0)
1655 log_write(0, LOG_MAIN, "host name alias list truncated for %s",
1656 sender_host_address);
1660 store_release_above(s + (slen = Ustrlen(s)) + 1);
1663 HDEBUG(D_host_lookup) debug_printf("IP address lookup yielded an "
1664 "empty name: treated as non-existent host name\n");
1667 if (Ustrspn(s, letter_digit_hyphen_dot) != slen)
1669 HDEBUG(D_host_lookup) debug_printf("IP address lookup yielded an "
1670 "illegal name (bad char): treated as non-existent host name\n");
1673 if (!sender_host_name) sender_host_name = s;
1675 while (*s) { *s = tolower(*s); s++; }
1678 *aptr = NULL; /* End of alias list */
1679 store_pool = old_pool; /* Reset store pool */
1681 /* If we've found a name, break out of the "order" loop */
1683 if (sender_host_name) break;
1686 /* If the DNS lookup deferred, we must also defer. */
1688 if (rc == DNS_AGAIN)
1690 HDEBUG(D_host_lookup)
1691 debug_printf("IP address PTR lookup gave temporary error\n");
1692 host_lookup_deferred = TRUE;
1697 /* Do a lookup using gethostbyaddr() - or equivalent */
1699 else if (strcmpic(ordername, US"byaddr") == 0)
1701 HDEBUG(D_host_lookup)
1702 debug_printf("IP address lookup using gethostbyaddr()\n");
1703 rc = host_name_lookup_byaddr();
1706 host_lookup_deferred = TRUE;
1707 return rc; /* Can't carry on */
1709 if (rc == OK) break; /* Found a name */
1711 } /* Loop for bydns/byaddr scanning */
1713 /* If we have failed to find a name, return FAIL and log when required.
1714 NB host_lookup_msg must be in permanent store. */
1716 if (!sender_host_name)
1718 if (host_checking || !f.log_testing_mode)
1719 log_write(L_host_lookup_failed, LOG_MAIN, "no host name found for IP "
1720 "address %s", sender_host_address);
1721 host_lookup_msg = US" (failed to find host name from IP address)";
1722 host_lookup_failed = TRUE;
1726 HDEBUG(D_host_lookup)
1728 uschar **aliases = sender_host_aliases;
1729 debug_printf("IP address lookup yielded \"%s\"\n", sender_host_name);
1730 while (*aliases) debug_printf(" alias \"%s\"\n", *aliases++);
1733 /* We need to verify that a forward lookup on the name we found does indeed
1734 correspond to the address. This is for security: in principle a malefactor who
1735 happened to own a reverse zone could set it to point to any names at all.
1737 This code was present in versions of Exim before 3.20. At that point I took it
1738 out because I thought that gethostbyaddr() did the check anyway. It turns out
1739 that this isn't always the case, so it's coming back in at 4.01. This version
1740 is actually better, because it also checks aliases.
1742 The code was made more robust at release 4.21. Prior to that, it accepted all
1743 the names if any of them had the correct IP address. Now the code checks all
1744 the names, and accepts only those that have the correct IP address. */
1746 save_hostname = sender_host_name; /* Save for error messages */
1747 aliases = sender_host_aliases;
1748 for (uschar * hname = sender_host_name; hname; hname = *aliases++)
1752 host_item h = { .next = NULL, .name = hname, .mx = MX_NONE, .address = NULL };
1754 { .request = sender_host_dnssec ? US"*" : NULL, .require = NULL };
1756 if ( (rc = host_find_bydns(&h, NULL, HOST_FIND_BY_A | HOST_FIND_BY_AAAA,
1757 NULL, NULL, NULL, &d, NULL, NULL)) == HOST_FOUND
1758 || rc == HOST_FOUND_LOCAL
1761 HDEBUG(D_host_lookup) debug_printf("checking addresses for %s\n", hname);
1763 /* If the forward lookup was not secure we cancel the is-secure variable */
1765 DEBUG(D_dns) debug_printf("Forward DNS security status: %s\n",
1766 h.dnssec == DS_YES ? "DNSSEC verified (AD)" : "unverified");
1767 if (h.dnssec != DS_YES) sender_host_dnssec = FALSE;
1769 for (host_item * hh = &h; hh; hh = hh->next)
1770 if (host_is_in_net(hh->address, sender_host_address, 0))
1772 HDEBUG(D_host_lookup) debug_printf(" %s OK\n", hh->address);
1777 HDEBUG(D_host_lookup) debug_printf(" %s\n", hh->address);
1779 if (!ok) HDEBUG(D_host_lookup)
1780 debug_printf("no IP address for %s matched %s\n", hname,
1781 sender_host_address);
1783 else if (rc == HOST_FIND_AGAIN)
1785 HDEBUG(D_host_lookup) debug_printf("temporary error for host name lookup\n");
1786 host_lookup_deferred = TRUE;
1787 sender_host_name = NULL;
1791 HDEBUG(D_host_lookup) debug_printf("no IP addresses found for %s\n", hname);
1793 /* If this name is no good, and it's the sender name, set it null pro tem;
1794 if it's an alias, just remove it from the list. */
1798 if (hname == sender_host_name) sender_host_name = NULL; else
1800 uschar **a; /* Don't amalgamate - some */
1801 a = --aliases; /* compilers grumble */
1802 while (*a != NULL) { *a = a[1]; a++; }
1807 /* If sender_host_name == NULL, it means we didn't like the name. Replace
1808 it with the first alias, if there is one. */
1810 if (sender_host_name == NULL && *sender_host_aliases != NULL)
1811 sender_host_name = *sender_host_aliases++;
1813 /* If we now have a main name, all is well. */
1815 if (sender_host_name != NULL) return OK;
1817 /* We have failed to find an address that matches. */
1819 HDEBUG(D_host_lookup)
1820 debug_printf("%s does not match any IP address for %s\n",
1821 sender_host_address, save_hostname);
1823 /* This message must be in permanent store */
1825 old_pool = store_pool;
1826 store_pool = POOL_PERM;
1827 host_lookup_msg = string_sprintf(" (%s does not match any IP address for %s)",
1828 sender_host_address, save_hostname);
1829 store_pool = old_pool;
1830 host_lookup_failed = TRUE;
1837 /*************************************************
1838 * Find IP address(es) for host by name *
1839 *************************************************/
1841 /* The input is a host_item structure with the name filled in and the address
1842 field set to NULL. We use gethostbyname() or getipnodebyname() or
1843 gethostbyname2(), as appropriate. Of course, these functions may use the DNS,
1844 but they do not do MX processing. It appears, however, that in some systems the
1845 current setting of resolver options is used when one of these functions calls
1846 the resolver. For this reason, we call dns_init() at the start, with arguments
1847 influenced by bits in "flags", just as we do for host_find_bydns().
1849 The second argument provides a host list (usually an IP list) of hosts to
1850 ignore. This makes it possible to ignore IPv6 link-local addresses or loopback
1851 addresses in unreasonable places.
1853 The lookup may result in a change of name. For compatibility with the dns
1854 lookup, return this via fully_qualified_name as well as updating the host item.
1855 The lookup may also yield more than one IP address, in which case chain on
1856 subsequent host_item structures.
1859 host a host item with the name and MX filled in;
1860 the address is to be filled in;
1861 multiple IP addresses cause other host items to be
1863 ignore_target_hosts a list of hosts to ignore
1864 flags HOST_FIND_QUALIFY_SINGLE ) passed to
1865 HOST_FIND_SEARCH_PARENTS ) dns_init()
1866 fully_qualified_name if not NULL, set to point to host name for
1867 compatibility with host_find_bydns
1868 local_host_check TRUE if a check for the local host is wanted
1870 Returns: HOST_FIND_FAILED Failed to find the host or domain
1871 HOST_FIND_AGAIN Try again later
1872 HOST_FOUND Host found - data filled in
1873 HOST_FOUND_LOCAL Host found and is the local host
1877 host_find_byname(host_item *host, const uschar *ignore_target_hosts, int flags,
1878 const uschar **fully_qualified_name, BOOL local_host_check)
1881 host_item *last = NULL;
1882 BOOL temp_error = FALSE;
1886 /* Copy the host name at this point to the value which is used for
1887 TLS certificate name checking, before anything modifies it. */
1889 host->certname = host->name;
1892 /* Make sure DNS options are set as required. This appears to be necessary in
1893 some circumstances when the get..byname() function actually calls the DNS. */
1895 dns_init((flags & HOST_FIND_QUALIFY_SINGLE) != 0,
1896 (flags & HOST_FIND_SEARCH_PARENTS) != 0,
1897 FALSE); /* Cannot retrieve dnssec status so do not request */
1899 /* In an IPv6 world, unless IPv6 has been disabled, we need to scan for both
1900 kinds of address, so go round the loop twice. Note that we have ensured that
1901 AF_INET6 is defined even in an IPv4 world, which makes for slightly tidier
1902 code. However, if dns_ipv4_lookup matches the domain, we also just do IPv4
1903 lookups here (except when testing standalone). */
1911 && match_isinlist(host->name, CUSS &dns_ipv4_lookup, 0,
1912 &domainlist_anchor, NULL, MCL_DOMAIN, TRUE, NULL) == OK)
1915 { af = AF_INET; times = 1; }
1917 { af = AF_INET6; times = 2; }
1919 /* No IPv6 support */
1921 #else /* HAVE_IPV6 */
1922 af = AF_INET; times = 1;
1923 #endif /* HAVE_IPV6 */
1925 /* Initialize the flag that gets set for DNS syntax check errors, so that the
1926 interface to this function can be similar to host_find_bydns. */
1928 f.host_find_failed_syntax = FALSE;
1930 /* Loop to look up both kinds of address in an IPv6 world */
1932 for (int i = 1; i <= times;
1934 af = AF_INET, /* If 2 passes, IPv4 on the second */
1940 struct hostent *hostdata;
1941 unsigned long time_msec = 0; /* compiler quietening */
1944 printf("Looking up: %s\n", host->name);
1947 if (slow_lookup_log) time_msec = get_time_in_ms();
1950 if (f.running_in_test_harness)
1951 hostdata = host_fake_gethostbyname(host->name, af, &error_num);
1954 #if HAVE_GETIPNODEBYNAME
1955 hostdata = getipnodebyname(CS host->name, af, 0, &error_num);
1957 hostdata = gethostbyname2(CS host->name, af);
1958 error_num = h_errno;
1962 #else /* not HAVE_IPV6 */
1963 if (f.running_in_test_harness)
1964 hostdata = host_fake_gethostbyname(host->name, af, &error_num);
1967 hostdata = gethostbyname(CS host->name);
1968 error_num = h_errno;
1970 #endif /* HAVE_IPV6 */
1972 if ( slow_lookup_log
1973 && (time_msec = get_time_in_ms() - time_msec) > slow_lookup_log)
1974 log_long_lookup(US"gethostbyname", host->name, time_msec);
1981 case HOST_NOT_FOUND: error = US"HOST_NOT_FOUND"; break;
1982 case TRY_AGAIN: error = US"TRY_AGAIN"; temp_error = TRUE; break;
1983 case NO_RECOVERY: error = US"NO_RECOVERY"; temp_error = TRUE; break;
1984 case NO_DATA: error = US"NO_DATA"; break;
1985 #if NO_DATA != NO_ADDRESS
1986 case NO_ADDRESS: error = US"NO_ADDRESS"; break;
1988 default: error = US"?"; break;
1991 DEBUG(D_host_lookup) debug_printf("%s(af=%s) returned %d (%s)\n",
1992 f.running_in_test_harness ? "host_fake_gethostbyname" :
1994 # if HAVE_GETIPNODEBYNAME
2002 af == AF_INET ? "inet" : "inet6", error_num, error);
2006 if (!(hostdata->h_addr_list)[0]) continue;
2008 /* Replace the name with the fully qualified one if necessary, and fill in
2009 the fully_qualified_name pointer. */
2011 if (hostdata->h_name[0] && Ustrcmp(host->name, hostdata->h_name) != 0)
2012 host->name = string_copy_dnsdomain(US hostdata->h_name);
2013 if (fully_qualified_name) *fully_qualified_name = host->name;
2015 /* Get the list of addresses. IPv4 and IPv6 addresses can be distinguished
2016 by their different lengths. Scan the list, ignoring any that are to be
2017 ignored, and build a chain from the rest. */
2019 ipv4_addr = hostdata->h_length == sizeof(struct in_addr);
2021 for (uschar ** addrlist = USS hostdata->h_addr_list; *addrlist; addrlist++)
2023 uschar *text_address =
2024 host_ntoa(ipv4_addr? AF_INET:AF_INET6, *addrlist, NULL, NULL);
2027 if ( ignore_target_hosts
2028 && verify_check_this_host(&ignore_target_hosts, NULL, host->name,
2029 text_address, NULL) == OK)
2031 DEBUG(D_host_lookup)
2032 debug_printf("ignored host %s [%s]\n", host->name, text_address);
2037 /* If this is the first address, last is NULL and we put the data in the
2042 host->address = text_address;
2043 host->port = PORT_NONE;
2044 host->status = hstatus_unknown;
2045 host->why = hwhy_unknown;
2046 host->dnssec = DS_UNK;
2050 /* Else add further host item blocks for any other addresses, keeping
2055 host_item *next = store_get(sizeof(host_item), GET_UNTAINTED);
2056 next->name = host->name;
2058 next->certname = host->certname;
2060 next->mx = host->mx;
2061 next->address = text_address;
2062 next->port = PORT_NONE;
2063 next->status = hstatus_unknown;
2064 next->why = hwhy_unknown;
2065 next->dnssec = DS_UNK;
2067 next->next = last->next;
2074 /* If no hosts were found, the address field in the original host block will be
2075 NULL. If temp_error is set, at least one of the lookups gave a temporary error,
2076 so we pass that back. */
2082 !message_id[0] && smtp_in
2083 ? string_sprintf("no IP address found for host %s (during %s)", host->name,
2084 smtp_get_connection_info()) :
2086 string_sprintf("no IP address found for host %s", host->name);
2088 HDEBUG(D_host_lookup) debug_printf("%s\n", msg);
2089 if (temp_error) goto RETURN_AGAIN;
2090 if (host_checking || !f.log_testing_mode)
2091 log_write(L_host_lookup_failed, LOG_MAIN, "%s", msg);
2092 return HOST_FIND_FAILED;
2095 /* Remove any duplicate IP addresses, then check to see if this is the local
2096 host if required. */
2098 host_remove_duplicates(host, &last);
2099 yield = local_host_check?
2100 host_scan_for_local_hosts(host, &last, NULL) : HOST_FOUND;
2102 HDEBUG(D_host_lookup)
2104 if (fully_qualified_name)
2105 debug_printf("fully qualified name = %s\n", *fully_qualified_name);
2106 debug_printf("%s looked up these IP addresses:\n",
2108 #if HAVE_GETIPNODEBYNAME
2117 for (const host_item * h = host; h != last->next; h = h->next)
2118 debug_printf(" name=%s address=%s\n", h->name,
2119 h->address ? h->address : US"<null>");
2122 /* Return the found status. */
2126 /* Handle the case when there is a temporary error. If the name matches
2127 dns_again_means_nonexist, return permanent rather than temporary failure. */
2133 const uschar *save = deliver_domain;
2134 deliver_domain = host->name; /* set $domain */
2135 rc = match_isinlist(host->name, CUSS &dns_again_means_nonexist, 0,
2136 &domainlist_anchor, NULL, MCL_DOMAIN, TRUE, NULL);
2137 deliver_domain = save;
2140 DEBUG(D_host_lookup) debug_printf("%s is in dns_again_means_nonexist: "
2141 "returning HOST_FIND_FAILED\n", host->name);
2142 return HOST_FIND_FAILED;
2145 return HOST_FIND_AGAIN;
2151 /*************************************************
2152 * Fill in a host address from the DNS *
2153 *************************************************/
2155 /* Given a host item, with its name, port and mx fields set, and its address
2156 field set to NULL, fill in its IP address from the DNS. If it is multi-homed,
2157 create additional host items for the additional addresses, copying all the
2158 other fields, and randomizing the order.
2160 On IPv6 systems, AAAA records are sought first, then A records.
2162 The host name may be changed if the DNS returns a different name - e.g. fully
2163 qualified or changed via CNAME. If fully_qualified_name is not NULL, dns_lookup
2164 ensures that it points to the fully qualified name. However, this is the fully
2165 qualified version of the original name; if a CNAME is involved, the actual
2166 canonical host name may be different again, and so we get it directly from the
2167 relevant RR. Note that we do NOT change the mx field of the host item in this
2168 function as it may be called to set the addresses of hosts taken from MX
2172 host points to the host item we're filling in
2173 lastptr points to pointer to last host item in a chain of
2174 host items (may be updated if host is last and gets
2175 extended because multihomed)
2176 ignore_target_hosts list of hosts to ignore
2177 allow_ip if TRUE, recognize an IP address and return it
2178 fully_qualified_name if not NULL, return fully qualified name here if
2179 the contents are different (i.e. it must be preset
2181 dnssec_request if TRUE request the AD bit
2182 dnssec_require if TRUE require the AD bit
2183 whichrrs select ipv4, ipv6 results
2185 Returns: HOST_FIND_FAILED couldn't find A record
2186 HOST_FIND_AGAIN try again later
2187 HOST_FIND_SECURITY dnssec required but not acheived
2188 HOST_FOUND found AAAA and/or A record(s)
2189 HOST_IGNORED found, but all IPs ignored
2193 set_address_from_dns(host_item *host, host_item **lastptr,
2194 const uschar *ignore_target_hosts, BOOL allow_ip,
2195 const uschar **fully_qualified_name,
2196 BOOL dnssec_request, BOOL dnssec_require, int whichrrs)
2198 host_item *thishostlast = NULL; /* Indicates not yet filled in anything */
2199 BOOL v6_find_again = FALSE;
2200 BOOL dnssec_fail = FALSE;
2205 /* Copy the host name at this point to the value which is used for
2206 TLS certificate name checking, before any CNAME-following modifies it. */
2208 host->certname = host->name;
2211 /* If allow_ip is set, a name which is an IP address returns that value
2212 as its address. This is used for MX records when allow_mx_to_ip is set, for
2213 those sites that feel they have to flaunt the RFC rules. */
2215 if (allow_ip && string_is_ip_address(host->name, NULL) != 0)
2218 if ( ignore_target_hosts
2219 && verify_check_this_host(&ignore_target_hosts, NULL, host->name,
2220 host->name, NULL) == OK)
2221 return HOST_IGNORED;
2224 host->address = host->name;
2228 dnsa = store_get_dns_answer();
2230 /* On an IPv6 system, unless IPv6 is disabled, go round the loop up to twice,
2231 looking for AAAA records the first time. However, unless doing standalone
2232 testing, we force an IPv4 lookup if the domain matches dns_ipv4_lookup global.
2233 On an IPv4 system, go round the loop once only, looking only for A records. */
2238 || !(whichrrs & HOST_FIND_BY_AAAA)
2240 && match_isinlist(host->name, CUSS &dns_ipv4_lookup, 0,
2241 &domainlist_anchor, NULL, MCL_DOMAIN, TRUE, NULL) == OK
2243 i = 0; /* look up A records only */
2245 #endif /* STAND_ALONE */
2247 i = 1; /* look up AAAA and A records */
2249 /* The IPv4 world */
2251 #else /* HAVE_IPV6 */
2252 i = 0; /* look up A records only */
2253 #endif /* HAVE_IPV6 */
2257 static int types[] = { T_A, T_AAAA };
2258 int type = types[i];
2259 int randoffset = i == (whichrrs & HOST_FIND_IPV4_FIRST ? 1 : 0)
2260 ? 500 : 0; /* Ensures v6/4 sort order */
2263 int rc = dns_lookup_timerwrap(dnsa, host->name, type, fully_qualified_name);
2264 lookup_dnssec_authenticated = !dnssec_request ? NULL
2265 : dns_is_secure(dnsa) ? US"yes" : US"no";
2268 if ( (dnssec_request || dnssec_require)
2269 && !dns_is_secure(dnsa)
2272 debug_printf("DNS lookup of %.256s (A/AAAA) requested AD, but got AA\n", host->name);
2274 /* We want to return HOST_FIND_AGAIN if one of the A or AAAA lookups
2275 fails or times out, but not if another one succeeds. (In the early
2276 IPv6 days there are name servers that always fail on AAAA, but are happy
2277 to give out an A record. We want to proceed with that A record.) */
2279 if (rc != DNS_SUCCEED)
2281 if (i == 0) /* Just tried for an A record, i.e. end of loop */
2283 if (host->address != NULL)
2284 i = HOST_FOUND; /* AAAA was found */
2285 else if (rc == DNS_AGAIN || rc == DNS_FAIL || v6_find_again)
2286 i = HOST_FIND_AGAIN;
2288 i = HOST_FIND_FAILED; /* DNS_NOMATCH or DNS_NODATA */
2292 /* Tried for an AAAA record: remember if this was a temporary
2293 error, and look for the next record type. */
2295 if (rc != DNS_NOMATCH && rc != DNS_NODATA) v6_find_again = TRUE;
2301 if (dns_is_secure(dnsa))
2303 DEBUG(D_host_lookup) debug_printf("%s A DNSSEC\n", host->name);
2304 if (host->dnssec == DS_UNK) /* set in host_find_bydns() */
2305 host->dnssec = DS_YES;
2312 DEBUG(D_host_lookup) debug_printf("dnssec fail on %s for %.256s",
2313 i>0 ? "AAAA" : "A", host->name);
2316 if (host->dnssec == DS_YES) /* set in host_find_bydns() */
2318 DEBUG(D_host_lookup) debug_printf("%s A cancel DNSSEC\n", host->name);
2319 host->dnssec = DS_NO;
2320 lookup_dnssec_authenticated = US"no";
2325 /* Lookup succeeded: fill in the given host item with the first non-ignored
2326 address found; create additional items for any others. A single A6 record
2327 may generate more than one address. The lookup had a chance to update the
2328 fqdn; we do not want any later times round the loop to do so. */
2330 fully_qualified_name = NULL;
2332 for (dns_record * rr = dns_next_rr(dnsa, &dnss, RESET_ANSWERS);
2334 rr = dns_next_rr(dnsa, &dnss, RESET_NEXT)) if (rr->type == type)
2336 dns_address * da = dns_address_from_rr(dnsa, rr);
2338 DEBUG(D_host_lookup)
2339 if (!da) debug_printf("no addresses extracted from A6 RR for %s\n",
2342 /* This loop runs only once for A and AAAA records, but may run
2343 several times for an A6 record that generated multiple addresses. */
2345 for (; da; da = da->next)
2348 if (ignore_target_hosts != NULL &&
2349 verify_check_this_host(&ignore_target_hosts, NULL,
2350 host->name, da->address, NULL) == OK)
2352 DEBUG(D_host_lookup)
2353 debug_printf("ignored host %s [%s]\n", host->name, da->address);
2358 /* If this is the first address, stick it in the given host block,
2359 and change the name if the returned RR has a different name. */
2361 if (thishostlast == NULL)
2363 if (strcmpic(host->name, rr->name) != 0)
2364 host->name = string_copy_dnsdomain(rr->name);
2365 host->address = da->address;
2366 host->sort_key = host->mx * 1000 + random_number(500) + randoffset;
2367 host->status = hstatus_unknown;
2368 host->why = hwhy_unknown;
2369 thishostlast = host;
2372 /* Not the first address. Check for, and ignore, duplicates. Then
2373 insert in the chain at a random point. */
2380 /* End of our local chain is specified by "thishostlast". */
2382 for (next = host;; next = next->next)
2384 if (Ustrcmp(CS da->address, next->address) == 0) break;
2385 if (next == thishostlast) { next = NULL; break; }
2387 if (next != NULL) continue; /* With loop for next address */
2389 /* Not a duplicate */
2391 new_sort_key = host->mx * 1000 + random_number(500) + randoffset;
2392 next = store_get(sizeof(host_item), GET_UNTAINTED);
2394 /* New address goes first: insert the new block after the first one
2395 (so as not to disturb the original pointer) but put the new address
2396 in the original block. */
2398 if (new_sort_key < host->sort_key)
2400 *next = *host; /* Copies port */
2402 host->address = da->address;
2403 host->sort_key = new_sort_key;
2404 if (thishostlast == host) thishostlast = next; /* Local last */
2405 if (*lastptr == host) *lastptr = next; /* Global last */
2408 /* Otherwise scan down the addresses for this host to find the
2409 one to insert after. */
2413 host_item *h = host;
2414 while (h != thishostlast)
2416 if (new_sort_key < h->next->sort_key) break;
2419 *next = *h; /* Copies port */
2421 next->address = da->address;
2422 next->sort_key = new_sort_key;
2423 if (h == thishostlast) thishostlast = next; /* Local last */
2424 if (h == *lastptr) *lastptr = next; /* Global last */
2431 /* Control gets here only if the second lookup (the A record) succeeded.
2432 However, the address may not be filled in if it was ignored. */
2437 ? HOST_FIND_SECURITY
2441 store_free_dns_answer(dnsa);
2448 /*************************************************
2449 * Find IP addresses and host names via DNS *
2450 *************************************************/
2452 /* The input is a host_item structure with the name field filled in and the
2453 address field set to NULL. This may be in a chain of other host items. The
2454 lookup may result in more than one IP address, in which case we must created
2455 new host blocks for the additional addresses, and insert them into the chain.
2456 The original name may not be fully qualified. Use the fully_qualified_name
2457 argument to return the official name, as returned by the resolver.
2460 host point to initial host item
2461 ignore_target_hosts a list of hosts to ignore
2462 whichrrs flags indicating which RRs to look for:
2463 HOST_FIND_BY_SRV => look for SRV
2464 HOST_FIND_BY_MX => look for MX
2465 HOST_FIND_BY_A => look for A
2466 HOST_FIND_BY_AAAA => look for AAAA
2467 also flags indicating how the lookup is done
2468 HOST_FIND_QUALIFY_SINGLE ) passed to the
2469 HOST_FIND_SEARCH_PARENTS ) resolver
2470 HOST_FIND_IPV4_FIRST => reverse usual result ordering
2471 HOST_FIND_IPV4_ONLY => MX results elide ipv6
2472 srv_service when SRV used, the service name
2473 srv_fail_domains DNS errors for these domains => assume nonexist
2474 mx_fail_domains DNS errors for these domains => assume nonexist
2475 dnssec_d.request => make dnssec request: domainlist
2476 dnssec_d.require => ditto and nonexist failures
2477 fully_qualified_name if not NULL, return fully-qualified name
2478 removed set TRUE if local host was removed from the list
2480 Returns: HOST_FIND_FAILED Failed to find the host or domain;
2481 if there was a syntax error,
2482 host_find_failed_syntax is set.
2483 HOST_FIND_AGAIN Could not resolve at this time
2484 HOST_FIND_SECURITY dnsssec required but not acheived
2485 HOST_FOUND Host found
2486 HOST_FOUND_LOCAL The lowest MX record points to this
2487 machine, if MX records were found, or
2488 an A record that was found contains
2489 an address of the local host
2493 host_find_bydns(host_item *host, const uschar *ignore_target_hosts, int whichrrs,
2494 uschar *srv_service, uschar *srv_fail_domains, uschar *mx_fail_domains,
2495 const dnssec_domains *dnssec_d,
2496 const uschar **fully_qualified_name, BOOL *removed)
2498 host_item *h, *last;
2502 dns_answer * dnsa = store_get_dns_answer();
2504 BOOL dnssec_require = dnssec_d
2505 && match_isinlist(host->name, CUSS &dnssec_d->require,
2506 0, &domainlist_anchor, NULL, MCL_DOMAIN, TRUE, NULL) == OK;
2507 BOOL dnssec_request = dnssec_require
2509 && match_isinlist(host->name, CUSS &dnssec_d->request,
2510 0, &domainlist_anchor, NULL, MCL_DOMAIN, TRUE, NULL) == OK);
2511 dnssec_status_t dnssec;
2513 /* Set the default fully qualified name to the incoming name, initialize the
2514 resolver if necessary, set up the relevant options, and initialize the flag
2515 that gets set for DNS syntax check errors. */
2517 if (fully_qualified_name != NULL) *fully_qualified_name = host->name;
2518 dns_init((whichrrs & HOST_FIND_QUALIFY_SINGLE) != 0,
2519 (whichrrs & HOST_FIND_SEARCH_PARENTS) != 0,
2521 f.host_find_failed_syntax = FALSE;
2523 /* First, if requested, look for SRV records. The service name is given; we
2524 assume TCP protocol. DNS domain names are constrained to a maximum of 256
2525 characters, so the code below should be safe. */
2527 if (whichrrs & HOST_FIND_BY_SRV)
2530 uschar * temp_fully_qualified_name;
2533 g = string_fmt_append(NULL, "_%s._tcp.%n%.256s",
2534 srv_service, &prefix_length, host->name);
2535 temp_fully_qualified_name = string_from_gstring(g);
2538 /* Search for SRV records. If the fully qualified name is different to
2539 the input name, pass back the new original domain, without the prepended
2543 lookup_dnssec_authenticated = NULL;
2544 rc = dns_lookup_timerwrap(dnsa, temp_fully_qualified_name, ind_type,
2545 CUSS &temp_fully_qualified_name);
2548 if ((dnssec_request || dnssec_require)
2549 && !dns_is_secure(dnsa)
2551 debug_printf("DNS lookup of %.256s (SRV) requested AD, but got AA\n", host->name);
2555 if (dns_is_secure(dnsa))
2556 { dnssec = DS_YES; lookup_dnssec_authenticated = US"yes"; }
2558 { dnssec = DS_NO; lookup_dnssec_authenticated = US"no"; }
2561 if (temp_fully_qualified_name != g->s && fully_qualified_name != NULL)
2562 *fully_qualified_name = temp_fully_qualified_name + prefix_length;
2564 /* On DNS failures, we give the "try again" error unless the domain is
2565 listed as one for which we continue. */
2567 if (rc == DNS_SUCCEED && dnssec_require && !dns_is_secure(dnsa))
2569 log_write(L_host_lookup_failed, LOG_MAIN,
2570 "dnssec fail on SRV for %.256s", host->name);
2573 if (rc == DNS_FAIL || rc == DNS_AGAIN)
2576 if (match_isinlist(host->name, CUSS &srv_fail_domains, 0,
2577 &domainlist_anchor, NULL, MCL_DOMAIN, TRUE, NULL) != OK)
2579 { yield = HOST_FIND_AGAIN; goto out; }
2580 DEBUG(D_host_lookup) debug_printf("DNS_%s treated as DNS_NODATA "
2581 "(domain in srv_fail_domains)\n", rc == DNS_FAIL ? "FAIL":"AGAIN");
2585 /* If we did not find any SRV records, search the DNS for MX records, if
2586 requested to do so. If the result is DNS_NOMATCH, it means there is no such
2587 domain, and there's no point in going on to look for address records with the
2588 same domain. The result will be DNS_NODATA if the domain exists but has no MX
2589 records. On DNS failures, we give the "try again" error unless the domain is
2590 listed as one for which we continue. */
2592 if (rc != DNS_SUCCEED && whichrrs & HOST_FIND_BY_MX)
2596 lookup_dnssec_authenticated = NULL;
2597 rc = dns_lookup_timerwrap(dnsa, host->name, ind_type, fully_qualified_name);
2600 if ( (dnssec_request || dnssec_require)
2601 && !dns_is_secure(dnsa)
2603 debug_printf("DNS lookup of %.256s (MX) requested AD, but got AA\n", host->name);
2606 if (dns_is_secure(dnsa))
2608 DEBUG(D_host_lookup) debug_printf("%s (MX resp) DNSSEC\n", host->name);
2609 dnssec = DS_YES; lookup_dnssec_authenticated = US"yes";
2613 dnssec = DS_NO; lookup_dnssec_authenticated = US"no";
2619 yield = HOST_FIND_FAILED; goto out;
2622 if (!dnssec_require || dns_is_secure(dnsa))
2624 DEBUG(D_host_lookup)
2625 debug_printf("dnssec fail on MX for %.256s", host->name);
2627 if (match_isinlist(host->name, CUSS &mx_fail_domains, 0,
2628 &domainlist_anchor, NULL, MCL_DOMAIN, TRUE, NULL) != OK)
2629 { yield = HOST_FIND_SECURITY; goto out; }
2637 if (match_isinlist(host->name, CUSS &mx_fail_domains, 0,
2638 &domainlist_anchor, NULL, MCL_DOMAIN, TRUE, NULL) != OK)
2640 { yield = HOST_FIND_AGAIN; goto out; }
2641 DEBUG(D_host_lookup) debug_printf("DNS_%s treated as DNS_NODATA "
2642 "(domain in mx_fail_domains)\n", (rc == DNS_FAIL)? "FAIL":"AGAIN");
2647 /* If we haven't found anything yet, and we are requested to do so, try for an
2648 A or AAAA record. If we find it (or them) check to see that it isn't the local
2651 if (rc != DNS_SUCCEED)
2653 if (!(whichrrs & (HOST_FIND_BY_A | HOST_FIND_BY_AAAA)))
2655 DEBUG(D_host_lookup) debug_printf("Address records are not being sought\n");
2656 yield = HOST_FIND_FAILED;
2660 last = host; /* End of local chainlet */
2662 host->port = PORT_NONE;
2663 host->dnssec = DS_UNK;
2664 lookup_dnssec_authenticated = NULL;
2665 rc = set_address_from_dns(host, &last, ignore_target_hosts, FALSE,
2666 fully_qualified_name, dnssec_request, dnssec_require, whichrrs);
2668 /* If one or more address records have been found, check that none of them
2669 are local. Since we know the host items all have their IP addresses
2670 inserted, host_scan_for_local_hosts() can only return HOST_FOUND or
2671 HOST_FOUND_LOCAL. We do not need to scan for duplicate IP addresses here,
2672 because set_address_from_dns() removes them. */
2674 if (rc == HOST_FOUND)
2675 rc = host_scan_for_local_hosts(host, &last, removed);
2677 if (rc == HOST_IGNORED) rc = HOST_FIND_FAILED; /* No special action */
2679 DEBUG(D_host_lookup)
2682 if (fully_qualified_name)
2683 debug_printf("fully qualified name = %s\n", *fully_qualified_name);
2684 for (host_item * h = host; h != last->next; h = h->next)
2685 debug_printf("%s %s mx=%d sort=%d %s\n", h->name,
2686 h->address ? h->address : US"<null>", h->mx, h->sort_key,
2687 h->status >= hstatus_unusable ? US"*" : US"");
2694 /* We have found one or more MX or SRV records. Sort them according to
2695 precedence. Put the data for the first one into the existing host block, and
2696 insert new host_item blocks into the chain for the remainder. For equal
2697 precedences one is supposed to randomize the order. To make this happen, the
2698 sorting is actually done on the MX value * 1000 + a random number. This is put
2699 into a host field called sort_key.
2701 In the case of hosts with both IPv6 and IPv4 addresses, we want to choose the
2702 IPv6 address in preference. At this stage, we don't know what kind of address
2703 the host has. We choose a random number < 500; if later we find an A record
2704 first, we add 500 to the random number. Then for any other address records, we
2705 use random numbers in the range 0-499 for AAAA records and 500-999 for A
2708 At this point we remove any duplicates that point to the same host, retaining
2709 only the one with the lowest precedence. We cannot yet check for precedence
2710 greater than that of the local host, because that test cannot be properly done
2711 until the addresses have been found - an MX record may point to a name for this
2712 host which is not the primary hostname. */
2714 last = NULL; /* Indicates that not even the first item is filled yet */
2716 for (dns_record * rr = dns_next_rr(dnsa, &dnss, RESET_ANSWERS);
2718 rr = dns_next_rr(dnsa, &dnss, RESET_NEXT)) if (rr->type == ind_type)
2720 int precedence, weight;
2721 int port = PORT_NONE;
2722 const uschar * s = rr->data; /* MUST be unsigned for GETSHORT */
2725 GETSHORT(precedence, s); /* Pointer s is advanced */
2727 /* For MX records, we use a random "weight" which causes multiple records of
2728 the same precedence to sort randomly. */
2730 if (ind_type == T_MX)
2731 weight = random_number(500);
2734 /* SRV records are specified with a port and a weight. The weight is used
2735 in a special algorithm. However, to start with, we just use it to order the
2736 records of equal priority (precedence). */
2737 GETSHORT(weight, s);
2741 /* Get the name of the host pointed to. */
2743 (void)dn_expand(dnsa->answer, dnsa->answer + dnsa->answerlen, s,
2744 (DN_EXPAND_ARG4_TYPE)data, sizeof(data));
2746 /* Check that we haven't already got this host on the chain; if we have,
2747 keep only the lower precedence. This situation shouldn't occur, but you
2748 never know what junk might get into the DNS (and this case has been seen on
2749 more than one occasion). */
2751 if (last) /* This is not the first record */
2753 host_item *prev = NULL;
2755 for (h = host; h != last->next; prev = h, h = h->next)
2756 if (strcmpic(h->name, data) == 0)
2758 DEBUG(D_host_lookup)
2759 debug_printf("discarded duplicate host %s (MX=%d)\n", data,
2760 precedence > h->mx ? precedence : h->mx);
2761 if (precedence >= h->mx) goto NEXT_MX_RR; /* Skip greater precedence */
2762 if (h == host) /* Override first item */
2765 host->sort_key = precedence * 1000 + weight;
2769 /* Unwanted host item is not the first in the chain, so we can get
2770 get rid of it by cutting it out. */
2772 prev->next = h->next;
2773 if (h == last) last = prev;
2778 /* If this is the first MX or SRV record, put the data into the existing host
2779 block. Otherwise, add a new block in the correct place; if it has to be
2780 before the first block, copy the first block's data to a new second block. */
2784 host->name = string_copy_dnsdomain(data);
2785 host->address = NULL;
2787 host->mx = precedence;
2788 host->sort_key = precedence * 1000 + weight;
2789 host->status = hstatus_unknown;
2790 host->why = hwhy_unknown;
2791 host->dnssec = dnssec;
2796 /* Make a new host item and seek the correct insertion place */
2798 int sort_key = precedence * 1000 + weight;
2799 host_item * next = store_get(sizeof(host_item), GET_UNTAINTED);
2800 next->name = string_copy_dnsdomain(data);
2801 next->address = NULL;
2803 next->mx = precedence;
2804 next->sort_key = sort_key;
2805 next->status = hstatus_unknown;
2806 next->why = hwhy_unknown;
2807 next->dnssec = dnssec;
2810 /* Handle the case when we have to insert before the first item. */
2812 if (sort_key < host->sort_key)
2819 if (last == host) last = next;
2823 /* Else scan down the items we have inserted as part of this exercise;
2824 don't go further. */
2826 for (h = host; h != last; h = h->next)
2827 if (sort_key < h->next->sort_key)
2829 next->next = h->next;
2834 /* Join on after the last host item that's part of this
2835 processing if we haven't stopped sooner. */
2839 next->next = last->next;
2846 NEXT_MX_RR: continue;
2849 if (!last) /* No rr of correct type; give up */
2851 yield = HOST_FIND_FAILED;
2855 /* If the list of hosts was obtained from SRV records, there are two things to
2856 do. First, if there is only one host, and it's name is ".", it means there is
2857 no SMTP service at this domain. Otherwise, we have to sort the hosts of equal
2858 priority according to their weights, using an algorithm that is defined in RFC
2859 2782. The hosts are currently sorted by priority and weight. For each priority
2860 group we have to pick off one host and put it first, and then repeat for any
2861 remaining in the same priority group. */
2863 if (ind_type == T_SRV)
2867 if (host == last && host->name[0] == 0)
2869 DEBUG(D_host_lookup) debug_printf("the single SRV record is \".\"\n");
2870 yield = HOST_FIND_FAILED;
2874 DEBUG(D_host_lookup)
2876 debug_printf("original ordering of hosts from SRV records:\n");
2877 for (h = host; h != last->next; h = h->next)
2878 debug_printf(" %s P=%d W=%d\n", h->name, h->mx, h->sort_key % 1000);
2881 for (pptr = &host, h = host; h != last; pptr = &h->next, h = h->next)
2886 /* Find the last following host that has the same precedence. At the same
2887 time, compute the sum of the weights and the running totals. These can be
2888 stored in the sort_key field. */
2890 for (hh = h; hh != last; hh = hh->next)
2892 int weight = hh->sort_key % 1000; /* was precedence * 1000 + weight */
2895 if (hh->mx != hh->next->mx) break;
2898 /* If there's more than one host at this precedence (priority), we need to
2899 pick one to go first. */
2905 int randomizer = random_number(sum + 1);
2907 for (ppptr = pptr, hhh = h;
2909 ppptr = &hhh->next, hhh = hhh->next)
2910 if (hhh->sort_key >= randomizer)
2913 /* hhh now points to the host that should go first; ppptr points to the
2914 place that points to it. Unfortunately, if the start of the minilist is
2915 the start of the entire list, we can't just swap the items over, because
2916 we must not change the value of host, since it is passed in from outside.
2917 One day, this could perhaps be changed.
2919 The special case is fudged by putting the new item *second* in the chain,
2920 and then transferring the data between the first and second items. We
2921 can't just swap the first and the chosen item, because that would mean
2922 that an item with zero weight might no longer be first. */
2926 *ppptr = hhh->next; /* Cuts it out of the chain */
2930 host_item temp = *h;
2933 hhh->next = temp.next;
2938 hhh->next = h; /* The rest of the chain follows it */
2939 *pptr = hhh; /* It takes the place of h */
2940 h = hhh; /* It's now the start of this minilist */
2945 /* A host has been chosen to be first at this priority and h now points
2946 to this host. There may be others at the same priority, or others at a
2947 different priority. Before we leave this host, we need to put back a sort
2948 key of the traditional MX kind, in case this host is multihomed, because
2949 the sort key is used for ordering the multiple IP addresses. We do not need
2950 to ensure that these new sort keys actually reflect the order of the hosts,
2953 h->sort_key = h->mx * 1000 + random_number(500);
2954 } /* Move on to the next host */
2957 /* Now we have to find IP addresses for all the hosts. We have ensured above
2958 that the names in all the host items are unique. Before release 4.61 we used to
2959 process records from the additional section in the DNS packet that returned the
2960 MX or SRV records. However, a DNS name server is free to drop any resource
2961 records from the additional section. In theory, this has always been a
2962 potential problem, but it is exacerbated by the advent of IPv6. If a host had
2963 several IPv4 addresses and some were not in the additional section, at least
2964 Exim would try the others. However, if a host had both IPv4 and IPv6 addresses
2965 and all the IPv4 (say) addresses were absent, Exim would try only for a IPv6
2966 connection, and never try an IPv4 address. When there was only IPv4
2967 connectivity, this was a disaster that did in practice occur.
2969 So, from release 4.61 onwards, we always search for A and AAAA records
2970 explicitly. The names shouldn't point to CNAMES, but we use the general lookup
2971 function that handles them, just in case. If any lookup gives a soft error,
2972 change the default yield.
2974 For these DNS lookups, we must disable qualify_single and search_parents;
2975 otherwise invalid host names obtained from MX or SRV records can cause trouble
2976 if they happen to match something local. */
2978 yield = HOST_FIND_FAILED; /* Default yield */
2979 dns_init(FALSE, FALSE, /* Disable qualify_single and search_parents */
2980 dnssec_request || dnssec_require);
2982 for (h = host; h != last->next; h = h->next)
2984 if (h->address) continue; /* Inserted by a multihomed host */
2986 rc = set_address_from_dns(h, &last, ignore_target_hosts, allow_mx_to_ip,
2987 NULL, dnssec_request, dnssec_require,
2988 whichrrs & HOST_FIND_IPV4_ONLY
2989 ? HOST_FIND_BY_A : HOST_FIND_BY_A | HOST_FIND_BY_AAAA);
2990 if (rc != HOST_FOUND)
2992 h->status = hstatus_unusable;
2995 case HOST_FIND_AGAIN: yield = rc; h->why = hwhy_deferred; break;
2996 case HOST_FIND_SECURITY: yield = rc; h->why = hwhy_insecure; break;
2997 case HOST_IGNORED: h->why = hwhy_ignored; break;
2998 default: h->why = hwhy_failed; break;
3003 /* Scan the list for any hosts that are marked unusable because they have
3004 been explicitly ignored, and remove them from the list, as if they did not
3005 exist. If we end up with just a single, ignored host, flatten its fields as if
3006 nothing was found. */
3008 if (ignore_target_hosts)
3010 host_item *prev = NULL;
3011 for (h = host; h != last->next; h = h->next)
3014 if (h->why != hwhy_ignored) /* Non ignored host, just continue */
3016 else if (prev == NULL) /* First host is ignored */
3018 if (h != last) /* First is not last */
3020 if (h->next == last) last = h; /* Overwrite it with next */
3021 *h = *(h->next); /* and reprocess it. */
3022 goto REDO; /* C should have redo, like Perl */
3025 else /* Ignored host is not first - */
3027 prev->next = h->next;
3028 if (h == last) last = prev;
3032 if (host->why == hwhy_ignored) host->address = NULL;
3035 /* There is still one complication in the case of IPv6. Although the code above
3036 arranges that IPv6 addresses take precedence over IPv4 addresses for multihomed
3037 hosts, it doesn't do this for addresses that apply to different hosts with the
3038 same MX precedence, because the sorting on MX precedence happens first. So we
3039 have to make another pass to check for this case. We ensure that, within a
3040 single MX preference value, IPv6 addresses come first. This can separate the
3041 addresses of a multihomed host, but that should not matter. */
3044 if (h != last && !disable_ipv6) for (h = host; h != last; h = h->next)
3047 host_item *next = h->next;
3049 if ( h->mx != next->mx /* If next is different MX */
3050 || !h->address /* OR this one is unset */
3052 continue; /* move on to next */
3054 if ( whichrrs & HOST_FIND_IPV4_FIRST
3055 ? !Ustrchr(h->address, ':') /* OR this one is IPv4 */
3057 && Ustrchr(next->address, ':') /* OR next is IPv6 */
3059 : Ustrchr(h->address, ':') /* OR this one is IPv6 */
3061 && !Ustrchr(next->address, ':') /* OR next is IPv4 */
3063 continue; /* move on to next */
3065 temp = *h; /* otherwise, swap */
3066 temp.next = next->next;
3073 /* Remove any duplicate IP addresses and then scan the list of hosts for any
3074 whose IP addresses are on the local host. If any are found, all hosts with the
3075 same or higher MX values are removed. However, if the local host has the lowest
3076 numbered MX, then HOST_FOUND_LOCAL is returned. Otherwise, if at least one host
3077 with an IP address is on the list, HOST_FOUND is returned. Otherwise,
3078 HOST_FIND_FAILED is returned, but in this case do not update the yield, as it
3079 might have been set to HOST_FIND_AGAIN just above here. If not, it will already
3080 be HOST_FIND_FAILED. */
3082 host_remove_duplicates(host, &last);
3083 rc = host_scan_for_local_hosts(host, &last, removed);
3084 if (rc != HOST_FIND_FAILED) yield = rc;
3086 DEBUG(D_host_lookup)
3088 if (fully_qualified_name)
3089 debug_printf("fully qualified name = %s\n", *fully_qualified_name);
3090 debug_printf("host_find_bydns yield = %s (%d); returned hosts:\n",
3091 yield == HOST_FOUND ? "HOST_FOUND" :
3092 yield == HOST_FOUND_LOCAL ? "HOST_FOUND_LOCAL" :
3093 yield == HOST_FIND_SECURITY ? "HOST_FIND_SECURITY" :
3094 yield == HOST_FIND_AGAIN ? "HOST_FIND_AGAIN" :
3095 yield == HOST_FIND_FAILED ? "HOST_FIND_FAILED" : "?",
3097 for (h = host; h != last->next; h = h->next)
3099 debug_printf(" %s %s MX=%d %s", h->name,
3100 !h->address ? US"<null>" : h->address, h->mx,
3101 h->dnssec == DS_YES ? US"DNSSEC " : US"");
3102 if (h->port != PORT_NONE) debug_printf("port=%d ", h->port);
3103 if (h->status >= hstatus_unusable) debug_printf("*");
3110 dns_init(FALSE, FALSE, FALSE); /* clear the dnssec bit for getaddrbyname */
3111 store_free_dns_answer(dnsa);
3119 /* Lookup TLSA record for host/port.
3120 Return: OK success with dnssec; DANE mode
3121 DEFER Do not use this host now, may retry later
3122 FAIL_FORCED No TLSA record; DANE not usable
3123 FAIL Do not use this connection
3127 tlsa_lookup(const host_item * host, dns_answer * dnsa, BOOL dane_required)
3130 const uschar * fullname = buffer;
3134 /* TLSA lookup string */
3135 (void)sprintf(CS buffer, "_%d._tcp.%.256s", host->port, host->name);
3137 rc = dns_lookup_timerwrap(dnsa, buffer, T_TLSA, &fullname);
3138 sec = dns_is_secure(dnsa);
3140 debug_printf("TLSA lookup ret %s %sDNSSEC\n", dns_rc_names[rc], sec ? "" : "not ");
3145 return DEFER; /* just defer this TLS'd conn */
3153 for (dns_record * rr = dns_next_rr(dnsa, &dnss, RESET_ANSWERS); rr;
3154 rr = dns_next_rr(dnsa, &dnss, RESET_NEXT))
3155 if (rr->type == T_TLSA && rr->size > 3)
3157 uint16_t payload_length = rr->size - 3;
3158 uschar s[MAX_TLSA_EXPANDED_SIZE], * sp = s, * p = US rr->data;
3160 sp += sprintf(CS sp, "%d ", *p++); /* usage */
3161 sp += sprintf(CS sp, "%d ", *p++); /* selector */
3162 sp += sprintf(CS sp, "%d ", *p++); /* matchtype */
3163 while (payload_length-- > 0 && sp-s < (MAX_TLSA_EXPANDED_SIZE - 4))
3164 sp += sprintf(CS sp, "%02x", *p++);
3166 debug_printf(" %s\n", s);
3171 log_write(0, LOG_MAIN,
3172 "DANE error: TLSA lookup for %s not DNSSEC", host->name);
3175 case DNS_NODATA: /* no TLSA RR for this lookup */
3176 case DNS_NOMATCH: /* no records at all for this lookup */
3177 return dane_required ? FAIL : FAIL_FORCED;
3181 return dane_required ? FAIL : DEFER;
3184 #endif /*SUPPORT_DANE*/
3188 /*************************************************
3189 **************************************************
3190 * Stand-alone test program *
3191 **************************************************
3192 *************************************************/
3196 int main(int argc, char **cargv)
3199 int whichrrs = HOST_FIND_BY_MX | HOST_FIND_BY_A | HOST_FIND_BY_AAAA;
3200 BOOL byname = FALSE;
3201 BOOL qualify_single = TRUE;
3202 BOOL search_parents = FALSE;
3203 BOOL request_dnssec = FALSE;
3204 BOOL require_dnssec = FALSE;
3205 uschar **argv = USS cargv;
3208 disable_ipv6 = FALSE;
3209 primary_hostname = US"";
3211 store_pool = POOL_MAIN;
3212 debug_selector = D_host_lookup|D_interface;
3213 debug_file = stdout;
3214 debug_fd = fileno(debug_file);
3216 printf("Exim stand-alone host functions test\n");
3218 host_find_interfaces();
3219 debug_selector = D_host_lookup | D_dns;
3221 if (argc > 1) primary_hostname = argv[1];
3223 /* So that debug level changes can be done first */
3225 dns_init(qualify_single, search_parents, FALSE);
3227 printf("Testing host lookup\n");
3229 while (Ufgets(buffer, 256, stdin) != NULL)
3232 int len = Ustrlen(buffer);
3233 uschar *fully_qualified_name;
3235 while (len > 0 && isspace(buffer[len-1])) len--;
3238 if (Ustrcmp(buffer, "q") == 0) break;
3240 if (Ustrcmp(buffer, "byname") == 0) byname = TRUE;
3241 else if (Ustrcmp(buffer, "no_byname") == 0) byname = FALSE;
3242 else if (Ustrcmp(buffer, "a_only") == 0) whichrrs = HOST_FIND_BY_A | HOST_FIND_BY_AAAA;
3243 else if (Ustrcmp(buffer, "mx_only") == 0) whichrrs = HOST_FIND_BY_MX;
3244 else if (Ustrcmp(buffer, "srv_only") == 0) whichrrs = HOST_FIND_BY_SRV;
3245 else if (Ustrcmp(buffer, "srv+a") == 0)
3246 whichrrs = HOST_FIND_BY_SRV | HOST_FIND_BY_A | HOST_FIND_BY_AAAA;
3247 else if (Ustrcmp(buffer, "srv+mx") == 0)
3248 whichrrs = HOST_FIND_BY_SRV | HOST_FIND_BY_MX;
3249 else if (Ustrcmp(buffer, "srv+mx+a") == 0)
3250 whichrrs = HOST_FIND_BY_SRV | HOST_FIND_BY_MX | HOST_FIND_BY_A | HOST_FIND_BY_AAAA;
3251 else if (Ustrcmp(buffer, "qualify_single") == 0) qualify_single = TRUE;
3252 else if (Ustrcmp(buffer, "no_qualify_single") == 0) qualify_single = FALSE;
3253 else if (Ustrcmp(buffer, "search_parents") == 0) search_parents = TRUE;
3254 else if (Ustrcmp(buffer, "no_search_parents") == 0) search_parents = FALSE;
3255 else if (Ustrcmp(buffer, "request_dnssec") == 0) request_dnssec = TRUE;
3256 else if (Ustrcmp(buffer, "no_request_dnssec") == 0) request_dnssec = FALSE;
3257 else if (Ustrcmp(buffer, "require_dnssec") == 0) require_dnssec = TRUE;
3258 else if (Ustrcmp(buffer, "no_require_dnssec") == 0) require_dnssec = FALSE;
3259 else if (Ustrcmp(buffer, "test_harness") == 0)
3260 f.running_in_test_harness = !f.running_in_test_harness;
3261 else if (Ustrcmp(buffer, "ipv6") == 0) disable_ipv6 = !disable_ipv6;
3262 else if (Ustrcmp(buffer, "res_debug") == 0)
3264 _res.options ^= RES_DEBUG;
3266 else if (Ustrncmp(buffer, "retrans", 7) == 0)
3268 (void)sscanf(CS(buffer+8), "%d", &dns_retrans);
3269 _res.retrans = dns_retrans;
3271 else if (Ustrncmp(buffer, "retry", 5) == 0)
3273 (void)sscanf(CS(buffer+6), "%d", &dns_retry);
3274 _res.retry = dns_retry;
3278 int flags = whichrrs;
3285 h.status = hstatus_unknown;
3286 h.why = hwhy_unknown;
3289 if (qualify_single) flags |= HOST_FIND_QUALIFY_SINGLE;
3290 if (search_parents) flags |= HOST_FIND_SEARCH_PARENTS;
3292 d.request = request_dnssec ? &h.name : NULL;
3293 d.require = require_dnssec ? &h.name : NULL;
3296 ? host_find_byname(&h, NULL, flags, &fully_qualified_name, TRUE)
3297 : host_find_bydns(&h, NULL, flags, US"smtp", NULL, NULL,
3298 &d, &fully_qualified_name, NULL);
3302 case HOST_FIND_FAILED: printf("Failed\n"); break;
3303 case HOST_FIND_AGAIN: printf("Again\n"); break;
3304 case HOST_FIND_SECURITY: printf("Security\n"); break;
3305 case HOST_FOUND_LOCAL: printf("Local\n"); break;
3312 printf("Testing host_aton\n");
3314 while (Ufgets(buffer, 256, stdin) != NULL)
3317 int len = Ustrlen(buffer);
3319 while (len > 0 && isspace(buffer[len-1])) len--;
3322 if (Ustrcmp(buffer, "q") == 0) break;
3324 len = host_aton(buffer, x);
3325 printf("length = %d ", len);
3326 for (int i = 0; i < len; i++)
3328 printf("%04x ", (x[i] >> 16) & 0xffff);
3329 printf("%04x ", x[i] & 0xffff);
3336 printf("Testing host_name_lookup\n");
3338 while (Ufgets(buffer, 256, stdin) != NULL)
3340 int len = Ustrlen(buffer);
3341 while (len > 0 && isspace(buffer[len-1])) len--;
3343 if (Ustrcmp(buffer, "q") == 0) break;
3344 sender_host_address = buffer;
3345 sender_host_name = NULL;
3346 sender_host_aliases = NULL;
3347 host_lookup_msg = US"";
3348 host_lookup_failed = FALSE;
3349 if (host_name_lookup() == FAIL) /* Debug causes printing */
3350 printf("Lookup failed:%s\n", host_lookup_msg);
3358 #endif /* STAND_ALONE */