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. */
9 /* Functions for finding hosts, either by gethostbyname(), gethostbyaddr(), or
10 directly via the DNS. When IPv6 is supported, getipnodebyname() and
11 getipnodebyaddr() may be used instead of gethostbyname() and gethostbyaddr(),
12 if the newer functions are available. This module also contains various other
13 functions concerned with hosts and addresses, and a random number function,
14 used for randomizing hosts with equal MXs but available for use in other parts
21 /* Static variable for preserving the list of interface addresses in case it is
22 used more than once. */
24 static ip_address_item *local_interface_data = NULL;
27 #ifdef USE_INET_NTOA_FIX
28 /*************************************************
29 * Replacement for broken inet_ntoa() *
30 *************************************************/
32 /* On IRIX systems, gcc uses a different structure passing convention to the
33 native libraries. This causes inet_ntoa() to always yield 0.0.0.0 or
34 255.255.255.255. To get round this, we provide a private version of the
35 function here. It is used only if USE_INET_NTOA_FIX is set, which should happen
36 only when gcc is in use on an IRIX system. Code send to me by J.T. Breitner,
40 as seen in comp.sys.sgi.admin
42 August 2005: Apparently this is also needed for AIX systems; USE_INET_NTOA_FIX
43 should now be set for them as well.
45 Arguments: sa an in_addr structure
46 Returns: pointer to static text string
50 inet_ntoa(struct in_addr sa)
52 static uschar addr[20];
53 sprintf(addr, "%d.%d.%d.%d",
64 /*************************************************
65 * Random number generator *
66 *************************************************/
68 /* This is a simple pseudo-random number generator. It does not have to be
69 very good for the uses to which it is put. When running the regression tests,
70 start with a fixed seed.
72 If you need better, see vaguely_random_number() which is potentially stronger,
73 if a crypto library is available, but might end up just calling this instead.
76 limit: one more than the largest number required
78 Returns: a pseudo-random number in the range 0 to limit-1
82 random_number(int limit)
87 if (f.running_in_test_harness)
91 int p = (int)getpid();
92 random_seed = (int)time(NULL) ^ ((p << 16) | p);
94 random_seed = 1103515245 * random_seed + 12345;
95 return (unsigned int)(random_seed >> 16) % limit;
98 /*************************************************
99 * Wrappers for logging lookup times *
100 *************************************************/
102 /* When the 'slow_lookup_log' variable is enabled, these wrappers will
103 write to the log file all (potential) dns lookups that take more than
104 slow_lookup_log milliseconds
108 log_long_lookup(const uschar * type, const uschar * data, unsigned long msec)
110 log_write(0, LOG_MAIN, "Long %s lookup for '%s': %lu msec",
115 /* returns the current system epoch time in milliseconds. */
119 struct timeval tmp_time;
120 unsigned long seconds, microseconds;
122 gettimeofday(&tmp_time, NULL);
123 seconds = (unsigned long) tmp_time.tv_sec;
124 microseconds = (unsigned long) tmp_time.tv_usec;
125 return seconds*1000 + microseconds/1000;
130 dns_lookup_timerwrap(dns_answer *dnsa, const uschar *name, int type,
131 const uschar **fully_qualified_name)
134 unsigned long time_msec;
136 if (!slow_lookup_log)
137 return dns_lookup(dnsa, name, type, fully_qualified_name);
139 time_msec = get_time_in_ms();
140 retval = dns_lookup(dnsa, name, type, fully_qualified_name);
141 if ((time_msec = get_time_in_ms() - time_msec) > slow_lookup_log)
142 log_long_lookup(dns_text_type(type), name, time_msec);
147 /*************************************************
148 * Replace gethostbyname() when testing *
149 *************************************************/
151 /* This function is called instead of gethostbyname(), gethostbyname2(), or
152 getipnodebyname() when running in the test harness. . It also
153 recognizes an unqualified "localhost" and forces it to the appropriate loopback
154 address. IP addresses are treated as literals. For other names, it uses the DNS
155 to find the host name. In the test harness, this means it will access only the
159 name the host name or a textual IP address
160 af AF_INET or AF_INET6
161 error_num where to put an error code:
162 HOST_NOT_FOUND/TRY_AGAIN/NO_RECOVERY/NO_DATA
164 Returns: a hostent structure or NULL for an error
167 static struct hostent *
168 host_fake_gethostbyname(const uschar *name, int af, int *error_num)
171 int alen = (af == AF_INET)? sizeof(struct in_addr):sizeof(struct in6_addr);
173 int alen = sizeof(struct in_addr);
177 const uschar *lname = name;
180 struct hostent *yield;
181 dns_answer * dnsa = store_get_dns_answer();
185 debug_printf("using host_fake_gethostbyname for %s (%s)\n", name,
186 af == AF_INET ? "IPv4" : "IPv6");
188 /* Handle unqualified "localhost" */
190 if (Ustrcmp(name, "localhost") == 0)
191 lname = af == AF_INET ? US"127.0.0.1" : US"::1";
193 /* Handle a literal IP address */
195 if ((ipa = string_is_ip_address(lname, NULL)) != 0)
196 if ( ipa == 4 && af == AF_INET
197 || ipa == 6 && af == AF_INET6)
200 yield = store_get(sizeof(struct hostent), GET_UNTAINTED);
201 alist = store_get(2 * sizeof(char *), GET_UNTAINTED);
202 adds = store_get(alen, GET_UNTAINTED);
203 yield->h_name = CS name;
204 yield->h_aliases = NULL;
205 yield->h_addrtype = af;
206 yield->h_length = alen;
207 yield->h_addr_list = CSS alist;
209 for (int n = host_aton(lname, x), i = 0; i < n; i++)
212 *adds++ = (y >> 24) & 255;
213 *adds++ = (y >> 16) & 255;
214 *adds++ = (y >> 8) & 255;
220 /* Wrong kind of literal address */
224 *error_num = HOST_NOT_FOUND;
229 /* Handle a host name */
233 int type = af == AF_INET ? T_A:T_AAAA;
234 int rc = dns_lookup_timerwrap(dnsa, lname, type, NULL);
237 lookup_dnssec_authenticated = NULL;
241 case DNS_SUCCEED: break;
242 case DNS_NOMATCH: *error_num = HOST_NOT_FOUND; yield = NULL; goto out;
243 case DNS_NODATA: *error_num = NO_DATA; yield = NULL; goto out;
244 case DNS_AGAIN: *error_num = TRY_AGAIN; yield = NULL; goto out;
246 case DNS_FAIL: *error_num = NO_RECOVERY; yield = NULL; goto out;
249 for (dns_record * rr = dns_next_rr(dnsa, &dnss, RESET_ANSWERS);
251 rr = dns_next_rr(dnsa, &dnss, RESET_NEXT)) if (rr->type == type)
254 yield = store_get(sizeof(struct hostent), GET_UNTAINTED);
255 alist = store_get((count + 1) * sizeof(char *), GET_UNTAINTED);
256 adds = store_get(count *alen, GET_UNTAINTED);
258 yield->h_name = CS name;
259 yield->h_aliases = NULL;
260 yield->h_addrtype = af;
261 yield->h_length = alen;
262 yield->h_addr_list = CSS alist;
264 for (dns_record * rr = dns_next_rr(dnsa, &dnss, RESET_ANSWERS);
266 rr = dns_next_rr(dnsa, &dnss, RESET_NEXT)) if (rr->type == type)
270 if (!(da = dns_address_from_rr(dnsa, rr))) break;
272 for (int n = host_aton(da->address, x), i = 0; i < n; i++)
275 *adds++ = (y >> 24) & 255;
276 *adds++ = (y >> 16) & 255;
277 *adds++ = (y >> 8) & 255;
286 store_free_dns_answer(dnsa);
292 /*************************************************
293 * Build chain of host items from list *
294 *************************************************/
296 /* This function builds a chain of host items from a textual list of host
297 names. It does not do any lookups. If randomize is true, the chain is build in
298 a randomized order. There may be multiple groups of independently randomized
299 hosts; they are delimited by a host name consisting of just "+".
302 anchor anchor for the chain
304 randomize TRUE for randomizing
310 host_build_hostlist(host_item **anchor, const uschar *list, BOOL randomize)
313 int fake_mx = MX_NONE; /* This value is actually -1 */
317 if (randomize) fake_mx--; /* Start at -2 for randomizing */
321 while ((name = string_nextinlist(&list, &sep, NULL, 0)))
325 if (name[0] == '+' && name[1] == 0) /* "+" delimits a randomized group */
326 { /* ignore if not randomizing */
327 if (randomize) fake_mx--;
331 h = store_get(sizeof(host_item), GET_UNTAINTED);
336 h->sort_key = randomize ? (-fake_mx)*1000 + random_number(1000) : 0;
337 h->status = hstatus_unknown;
338 h->why = hwhy_unknown;
348 host_item *hh = *anchor;
349 if (h->sort_key < hh->sort_key)
356 while (hh->next && h->sort_key >= hh->next->sort_key)
366 /*************************************************
367 * Get port from a host item's name *
368 *************************************************/
370 /* This function is called when finding the IP address for a host that is in a
371 list of hosts explicitly configured, such as in the manualroute router, or in a
372 fallback hosts list. We see if there is a port specification at the end of the
373 host name, and if so, remove it. A minimum length of 3 is required for the
374 original name; nothing shorter is recognized as having a port.
376 We test for a name ending with a sequence of digits; if preceded by colon we
377 have a port if the character before the colon is ] and the name starts with [
378 or if there are no other colons in the name (i.e. it's not an IPv6 address).
380 Arguments: pointer to the host item
381 Returns: a port number or PORT_NONE
385 host_item_get_port(host_item *h)
389 int len = Ustrlen(h->name);
391 if (len < 3 || (p = h->name + len - 1, !isdigit(*p))) return PORT_NONE;
393 /* Extract potential port number */
398 while (p > h->name + 1 && isdigit(*p))
400 port += (*p-- - '0') * x;
404 /* The smallest value of p at this point is h->name + 1. */
406 if (*p != ':') return PORT_NONE;
408 if (p[-1] == ']' && h->name[0] == '[')
409 h->name = string_copyn(h->name + 1, p - h->name - 2);
410 else if (Ustrchr(h->name, ':') == p)
411 h->name = string_copyn(h->name, p - h->name);
412 else return PORT_NONE;
414 DEBUG(D_route|D_host_lookup) debug_printf("host=%s port=%d\n", h->name, port);
420 #ifndef STAND_ALONE /* Omit when standalone testing */
422 /*************************************************
423 * Build sender_fullhost and sender_rcvhost *
424 *************************************************/
426 /* This function is called when sender_host_name and/or sender_helo_name
427 have been set. Or might have been set - for a local message read off the spool
428 they won't be. In that case, do nothing. Otherwise, set up the fullhost string
431 (a) No sender_host_name or sender_helo_name: "[ip address]"
432 (b) Just sender_host_name: "host_name [ip address]"
433 (c) Just sender_helo_name: "(helo_name) [ip address]" unless helo is IP
434 in which case: "[ip address}"
435 (d) The two are identical: "host_name [ip address]" includes helo = IP
436 (e) The two are different: "host_name (helo_name) [ip address]"
438 If log_incoming_port is set, the sending host's port number is added to the IP
441 This function also builds sender_rcvhost for use in Received: lines, whose
442 syntax is a bit different. This value also includes the RFC 1413 identity.
443 There wouldn't be two different variables if I had got all this right in the
446 Because this data may survive over more than one incoming SMTP message, it has
447 to be in permanent store. However, STARTTLS has to be forgotten and redone
448 on a multi-message conn, so this will be called once per message then. Hence
449 we use malloc, so we can free.
456 host_build_sender_fullhost(void)
458 BOOL show_helo = TRUE;
459 uschar * address, * fullhost, * rcvhost;
463 if (!sender_host_address) return;
465 reset_point = store_mark();
467 /* Set up address, with or without the port. After discussion, it seems that
468 the only format that doesn't cause trouble is [aaaa]:pppp. However, we can't
469 use this directly as the first item for Received: because it ain't an RFC 2822
472 address = string_sprintf("[%s]:%d", sender_host_address, sender_host_port);
473 if (!LOGGING(incoming_port) || sender_host_port <= 0)
474 *(Ustrrchr(address, ':')) = 0;
476 /* If there's no EHLO/HELO data, we can't show it. */
478 if (!sender_helo_name) show_helo = FALSE;
480 /* If HELO/EHLO was followed by an IP literal, it's messy because of two
481 features of IPv6. Firstly, there's the "IPv6:" prefix (Exim is liberal and
482 doesn't require this, for historical reasons). Secondly, IPv6 addresses may not
483 be given in canonical form, so we have to canonicalize them before comparing. As
484 it happens, the code works for both IPv4 and IPv6. */
486 else if (sender_helo_name[0] == '[' &&
487 sender_helo_name[(len=Ustrlen(sender_helo_name))-1] == ']')
492 if (strncmpic(sender_helo_name + 1, US"IPv6:", 5) == 0) offset += 5;
493 if (strncmpic(sender_helo_name + 1, US"IPv4:", 5) == 0) offset += 5;
495 helo_ip = string_copyn(sender_helo_name + offset, len - offset - 1);
497 if (string_is_ip_address(helo_ip, NULL) != 0)
501 uschar ipx[48], ipy[48]; /* large enough for full IPv6 */
503 sizex = host_aton(helo_ip, x);
504 sizey = host_aton(sender_host_address, y);
506 (void)host_nmtoa(sizex, x, -1, ipx, ':');
507 (void)host_nmtoa(sizey, y, -1, ipy, ':');
509 if (strcmpic(ipx, ipy) == 0) show_helo = FALSE;
513 /* Host name is not verified */
515 if (!sender_host_name)
517 uschar *portptr = Ustrstr(address, "]:");
519 int adlen; /* Sun compiler doesn't like ++ in initializers */
521 adlen = portptr ? (++portptr - address) : Ustrlen(address);
522 fullhost = sender_helo_name
523 ? string_sprintf("(%s) %s", sender_helo_name, address)
526 g = string_catn(NULL, address, adlen);
528 if (sender_ident || show_helo || portptr)
531 g = string_catn(g, US" (", 2);
535 g = string_append(g, 2, US"port=", portptr + 1);
538 g = string_append(g, 2,
539 firstptr == g->ptr ? US"helo=" : US" helo=", sender_helo_name);
542 g = string_append(g, 2,
543 firstptr == g->ptr ? US"ident=" : US" ident=", sender_ident);
545 g = string_catn(g, US")", 1);
548 rcvhost = string_from_gstring(g);
551 /* Host name is known and verified. Unless we've already found that the HELO
552 data matches the IP address, compare it with the name. */
556 if (show_helo && strcmpic(sender_host_name, sender_helo_name) == 0)
561 fullhost = string_sprintf("%s (%s) %s", sender_host_name,
562 sender_helo_name, address);
563 rcvhost = sender_ident
564 ? string_sprintf("%s\n\t(%s helo=%s ident=%s)", sender_host_name,
565 address, sender_helo_name, sender_ident)
566 : string_sprintf("%s (%s helo=%s)", sender_host_name,
567 address, sender_helo_name);
571 fullhost = string_sprintf("%s %s", sender_host_name, address);
572 rcvhost = sender_ident
573 ? string_sprintf("%s (%s ident=%s)", sender_host_name, address,
575 : string_sprintf("%s (%s)", sender_host_name, address);
579 sender_fullhost = string_copy_perm(fullhost, TRUE);
580 sender_rcvhost = string_copy_perm(rcvhost, TRUE);
582 store_reset(reset_point);
584 DEBUG(D_host_lookup) debug_printf("sender_fullhost = %s\n", sender_fullhost);
585 DEBUG(D_host_lookup) debug_printf("sender_rcvhost = %s\n", sender_rcvhost);
590 /*************************************************
591 * Build host+ident message *
592 *************************************************/
594 /* Used when logging rejections and various ACL and SMTP incidents. The text
595 return depends on whether sender_fullhost and sender_ident are set or not:
597 no ident, no host => U=unknown
598 no ident, host set => H=sender_fullhost
599 ident set, no host => U=ident
600 ident set, host set => H=sender_fullhost U=ident
602 Use taint-unchecked routines on the assumption we'll never expand the results.
605 useflag TRUE if first item to be flagged (H= or U=); if there are two
606 items, the second is always flagged
608 Returns: pointer to a string in big_buffer
612 host_and_ident(BOOL useflag)
614 if (!sender_fullhost)
615 string_format_nt(big_buffer, big_buffer_size, "%s%s", useflag ? "U=" : "",
616 sender_ident ? sender_ident : US"unknown");
619 uschar * flag = useflag ? US"H=" : US"";
620 uschar * iface = US"";
621 if (LOGGING(incoming_interface) && interface_address)
622 iface = string_sprintf(" I=[%s]:%d", interface_address, interface_port);
624 string_format_nt(big_buffer, big_buffer_size, "%s%s%s U=%s",
625 flag, sender_fullhost, iface, sender_ident);
627 string_format_nt(big_buffer, big_buffer_size, "%s%s%s",
628 flag, sender_fullhost, iface);
633 #endif /* STAND_ALONE */
638 /*************************************************
639 * Build list of local interfaces *
640 *************************************************/
642 /* This function interprets the contents of the local_interfaces or
643 extra_local_interfaces options, and creates an ip_address_item block for each
644 item on the list. There is no special interpretation of any IP addresses; in
645 particular, 0.0.0.0 and ::0 are returned without modification. If any address
646 includes a port, it is set in the block. Otherwise the port value is set to
651 name the name of the option being expanded
653 Returns: a chain of ip_address_items, each containing to a textual
654 version of an IP address, and a port number (host order) or
655 zero if no port was given with the address
659 host_build_ifacelist(const uschar *list, uschar *name)
663 ip_address_item * yield = NULL, * last = NULL, * next;
665 while ((s = string_nextinlist(&list, &sep, NULL, 0)))
668 int port = host_address_extract_port(s); /* Leaves just the IP address */
670 if (!(ipv = string_is_ip_address(s, NULL)))
671 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Malformed IP address \"%s\" in %s",
674 /* Skip IPv6 addresses if IPv6 is disabled. */
676 if (disable_ipv6 && ipv == 6) continue;
678 /* This use of strcpy() is OK because we have checked that s is a valid IP
679 address above. The field in the ip_address_item is large enough to hold an
682 next = store_get(sizeof(ip_address_item), list);
684 Ustrcpy(next->address, s);
686 next->v6_include_v4 = FALSE;
705 /*************************************************
706 * Find addresses on local interfaces *
707 *************************************************/
709 /* This function finds the addresses of local IP interfaces. These are used
710 when testing for routing to the local host. As the function may be called more
711 than once, the list is preserved in permanent store, pointed to by a static
712 variable, to save doing the work more than once per process.
714 The generic list of interfaces is obtained by calling host_build_ifacelist()
715 for local_interfaces and extra_local_interfaces. This list scanned to remove
716 duplicates (which may exist with different ports - not relevant here). If
717 either of the wildcard IP addresses (0.0.0.0 and ::0) are encountered, they are
718 replaced by the appropriate (IPv4 or IPv6) list of actual local interfaces,
719 obtained from os_find_running_interfaces().
722 Returns: a chain of ip_address_items, each containing to a textual
723 version of an IP address; the port numbers are not relevant
727 /* First, a local subfunction to add an interface to a list in permanent store,
728 but only if there isn't a previous copy of that address on the list. */
730 static ip_address_item *
731 add_unique_interface(ip_address_item *list, ip_address_item *ipa)
733 ip_address_item *ipa2;
734 for (ipa2 = list; ipa2; ipa2 = ipa2->next)
735 if (Ustrcmp(ipa2->address, ipa->address) == 0) return list;
736 ipa2 = store_get_perm(sizeof(ip_address_item), FALSE);
743 /* This is the globally visible function */
746 host_find_interfaces(void)
748 ip_address_item *running_interfaces = NULL;
750 if (!local_interface_data)
752 void *reset_item = store_mark();
753 ip_address_item *dlist = host_build_ifacelist(CUS local_interfaces,
754 US"local_interfaces");
755 ip_address_item *xlist = host_build_ifacelist(CUS extra_local_interfaces,
756 US"extra_local_interfaces");
757 ip_address_item *ipa;
759 if (!dlist) dlist = xlist;
762 for (ipa = dlist; ipa->next; ipa = ipa->next) ;
766 for (ipa = dlist; ipa; ipa = ipa->next)
768 if (Ustrcmp(ipa->address, "0.0.0.0") == 0 ||
769 Ustrcmp(ipa->address, "::0") == 0)
771 BOOL ipv6 = ipa->address[0] == ':';
772 if (!running_interfaces)
773 running_interfaces = os_find_running_interfaces();
774 for (ip_address_item * ipa2 = running_interfaces; ipa2; ipa2 = ipa2->next)
775 if ((Ustrchr(ipa2->address, ':') != NULL) == ipv6)
776 local_interface_data = add_unique_interface(local_interface_data,
781 local_interface_data = add_unique_interface(local_interface_data, ipa);
784 debug_printf("Configured local interface: address=%s", ipa->address);
785 if (ipa->port != 0) debug_printf(" port=%d", ipa->port);
790 store_reset(reset_item);
793 return local_interface_data;
800 /*************************************************
801 * Convert network IP address to text *
802 *************************************************/
804 /* Given an IPv4 or IPv6 address in binary, convert it to a text
805 string and return the result in a piece of new store. The address can
806 either be given directly, or passed over in a sockaddr structure. Note
807 that this isn't the converse of host_aton() because of byte ordering
808 differences. See host_nmtoa() below.
811 type if < 0 then arg points to a sockaddr, else
812 either AF_INET or AF_INET6
813 arg points to a sockaddr if type is < 0, or
814 points to an IPv4 address (32 bits), or
815 points to an IPv6 address (128 bits),
816 in both cases, in network byte order
817 buffer if NULL, the result is returned in gotten store;
818 else points to a buffer to hold the answer
819 portptr points to where to put the port number, if non NULL; only
822 Returns: pointer to character string
826 host_ntoa(int type, const void *arg, uschar *buffer, int *portptr)
830 /* The new world. It is annoying that we have to fish out the address from
831 different places in the block, depending on what kind of address it is. It
832 is also a pain that inet_ntop() returns a const uschar *, whereas the IPv4
833 function inet_ntoa() returns just uschar *, and some picky compilers insist
834 on warning if one assigns a const uschar * to a uschar *. Hence the casts. */
837 uschar addr_buffer[46];
840 int family = ((struct sockaddr *)arg)->sa_family;
841 if (family == AF_INET6)
843 struct sockaddr_in6 *sk = (struct sockaddr_in6 *)arg;
844 yield = US inet_ntop(family, &(sk->sin6_addr), CS addr_buffer,
845 sizeof(addr_buffer));
846 if (portptr) *portptr = ntohs(sk->sin6_port);
850 struct sockaddr_in *sk = (struct sockaddr_in *)arg;
851 yield = US inet_ntop(family, &(sk->sin_addr), CS addr_buffer,
852 sizeof(addr_buffer));
853 if (portptr) *portptr = ntohs(sk->sin_port);
858 yield = US inet_ntop(type, arg, CS addr_buffer, sizeof(addr_buffer));
861 /* If the result is a mapped IPv4 address, show it in V4 format. */
863 if (Ustrncmp(yield, "::ffff:", 7) == 0) yield += 7;
865 #else /* HAVE_IPV6 */
871 yield = US inet_ntoa(((struct sockaddr_in *)arg)->sin_addr);
872 if (portptr) *portptr = ntohs(((struct sockaddr_in *)arg)->sin_port);
875 yield = US inet_ntoa(*((struct in_addr *)arg));
878 /* If there is no buffer, put the string into some new store. */
880 if (!buffer) buffer = store_get(46, GET_UNTAINTED);
882 /* Callers of this function with a non-NULL buffer must ensure that it is
883 large enough to hold an IPv6 address, namely, at least 46 bytes. That's what
884 makes this use of strcpy() OK.
885 If the library returned apparently an apparently tainted string, clean it;
886 we trust IP addresses. */
888 string_format_nt(buffer, 46, "%s", yield);
895 /*************************************************
896 * Convert address text to binary *
897 *************************************************/
899 /* Given the textual form of an IP address, convert it to binary in an
900 array of ints. IPv4 addresses occupy one int; IPv6 addresses occupy 4 ints.
901 The result has the first byte in the most significant byte of the first int. In
902 other words, the result is not in network byte order, but in host byte order.
903 As a result, this is not the converse of host_ntoa(), which expects network
904 byte order. See host_nmtoa() below.
907 address points to the textual address, checked for syntax
908 bin points to an array of 4 ints
910 Returns: the number of ints used
914 host_aton(const uschar *address, int *bin)
919 /* Handle IPv6 address, which may end with an IPv4 address. It may also end
920 with a "scope", introduced by a percent sign. This code is NOT enclosed in #if
921 HAVE_IPV6 in order that IPv6 addresses are recognized even if IPv6 is not
924 if (Ustrchr(address, ':') != NULL)
926 const uschar *p = address;
927 const uschar *component[8];
928 BOOL ipv4_ends = FALSE;
934 /* If the address starts with a colon, it will start with two colons.
935 Just lose the first one, which will leave a null first component. */
939 /* Split the address into components separated by colons. The input address
940 is supposed to be checked for syntax. There was a case where this was
941 overlooked; to guard against that happening again, check here and crash if
942 there are too many components. */
944 while (*p != 0 && *p != '%')
946 int len = Ustrcspn(p, ":%");
947 if (len == 0) nulloffset = ci;
948 if (ci > 7) log_write(0, LOG_MAIN|LOG_PANIC_DIE,
949 "Internal error: invalid IPv6 address \"%s\" passed to host_aton()",
956 /* If the final component contains a dot, it is a trailing v4 address.
957 As the syntax is known to be checked, just set up for a trailing
958 v4 address and restrict the v6 part to 6 components. */
960 if (Ustrchr(component[ci-1], '.') != NULL)
962 address = component[--ci];
968 /* If there are fewer than 6 or 8 components, we have to insert some
969 more empty ones in the middle. */
973 int insert_count = v6count - ci;
974 for (i = v6count-1; i > nulloffset + insert_count; i--)
975 component[i] = component[i - insert_count];
976 while (i > nulloffset) component[i--] = US"";
979 /* Now turn the components into binary in pairs and bung them
980 into the vector of ints. */
982 for (i = 0; i < v6count; i += 2)
983 bin[i/2] = (Ustrtol(component[i], NULL, 16) << 16) +
984 Ustrtol(component[i+1], NULL, 16);
986 /* If there was no terminating v4 component, we are done. */
988 if (!ipv4_ends) return 4;
991 /* Handle IPv4 address */
993 (void)sscanf(CS address, "%d.%d.%d.%d", x, x+1, x+2, x+3);
994 bin[v4offset] = ((uint)x[0] << 24) + (x[1] << 16) + (x[2] << 8) + x[3];
999 /*************************************************
1000 * Apply mask to an IP address *
1001 *************************************************/
1003 /* Mask an address held in 1 or 4 ints, with the ms bit in the ms bit of the
1007 count the number of ints
1008 binary points to the ints to be masked
1009 mask the count of ms bits to leave, or -1 if no masking
1015 host_mask(int count, int *binary, int mask)
1017 if (mask < 0) mask = 99999;
1018 for (int i = 0; i < count; i++)
1021 if (mask == 0) wordmask = 0;
1024 wordmask = (uint)(-1) << (32 - mask);
1032 binary[i] &= wordmask;
1039 /*************************************************
1040 * Convert masked IP address in ints to text *
1041 *************************************************/
1043 /* We can't use host_ntoa() because it assumes the binary values are in network
1044 byte order, and these are the result of host_aton(), which puts them in ints in
1045 host byte order. Also, we really want IPv6 addresses to be in a canonical
1046 format, so we output them with no abbreviation. In a number of cases we can't
1047 use the normal colon separator in them because it terminates keys in lsearch
1048 files, so we want to use dot instead. There's an argument that specifies what
1049 to use for IPv6 addresses.
1052 count 1 or 4 (number of ints)
1053 binary points to the ints
1054 mask mask value; if < 0 don't add to result
1055 buffer big enough to hold the result
1056 sep component separator character for IPv6 addresses
1058 Returns: the number of characters placed in buffer, not counting
1063 host_nmtoa(int count, int *binary, int mask, uschar *buffer, int sep)
1066 uschar *tt = buffer;
1071 for (int i = 24; i >= 0; i -= 8)
1072 tt += sprintf(CS tt, "%d.", (j >> i) & 255);
1075 for (int i = 0; i < 4; i++)
1078 tt += sprintf(CS tt, "%04x%c%04x%c", (j >> 16) & 0xffff, sep, j & 0xffff, sep);
1081 tt--; /* lose final separator */
1086 tt += sprintf(CS tt, "/%d", mask);
1092 /* Like host_nmtoa() but: ipv6-only, canonical output, no mask
1095 binary points to the ints
1096 buffer big enough to hold the result
1098 Returns: the number of characters placed in buffer, not counting
1103 ipv6_nmtoa(int * binary, uschar * buffer)
1106 uschar * c = buffer;
1107 uschar * d = NULL; /* shut insufficiently "clever" compiler up */
1109 for (i = 0; i < 4; i++)
1110 { /* expand to text */
1112 c += sprintf(CS c, "%x:%x:", (j >> 16) & 0xffff, j & 0xffff);
1115 for (c = buffer, k = -1, i = 0; i < 8; i++)
1116 { /* find longest 0-group sequence */
1117 if (*c == '0') /* must be "0:" */
1121 while (c[2] == '0') i++, c += 2;
1124 k = i-j; /* length of sequence */
1125 d = s; /* start of sequence */
1128 while (*++c != ':') ;
1132 *--c = '\0'; /* drop trailing colon */
1134 /* debug_printf("%s: D k %d <%s> <%s>\n", __FUNCTION__, k, buffer, buffer + 2*(k+1)); */
1138 if (d == buffer) c--; /* need extra colon */
1139 *d++ = ':'; /* 1st 0 */
1140 while ((*d++ = *c++)) ;
1150 /*************************************************
1151 * Check port for tls_on_connect *
1152 *************************************************/
1154 /* This function checks whether a given incoming port is configured for tls-
1155 on-connect. It is called from the daemon and from inetd handling. If the global
1156 option tls_on_connect is already set, all ports operate this way. Otherwise, we
1157 check the tls_on_connect_ports option for a list of ports.
1159 Argument: a port number
1160 Returns: TRUE or FALSE
1164 host_is_tls_on_connect_port(int port)
1167 const uschar * list = tls_in.on_connect_ports;
1169 if (tls_in.on_connect) return TRUE;
1171 for (uschar * s, * end; s = string_nextinlist(&list, &sep, NULL, 0); )
1172 if (Ustrtol(s, &end, 10) == port)
1180 /*************************************************
1181 * Check whether host is in a network *
1182 *************************************************/
1184 /* This function checks whether a given IP address matches a pattern that
1185 represents either a single host, or a network (using CIDR notation). The caller
1186 of this function must check the syntax of the arguments before calling it.
1189 host string representation of the ip-address to check
1190 net string representation of the network, with optional CIDR mask
1191 maskoffset offset to the / that introduces the mask in the key
1192 zero if there is no mask
1195 TRUE the host is inside the network
1196 FALSE the host is NOT inside the network
1200 host_is_in_net(const uschar *host, const uschar *net, int maskoffset)
1205 int size = host_aton(net, address);
1208 /* No mask => all bits to be checked */
1210 if (maskoffset == 0) mlen = 99999; /* Big number */
1211 else mlen = Uatoi(net + maskoffset + 1);
1213 /* Convert the incoming address to binary. */
1215 insize = host_aton(host, incoming);
1217 /* Convert IPv4 addresses given in IPv6 compatible mode, which represent
1218 connections from IPv4 hosts to IPv6 hosts, that is, addresses of the form
1219 ::ffff:<v4address>, to IPv4 format. */
1221 if (insize == 4 && incoming[0] == 0 && incoming[1] == 0 &&
1222 incoming[2] == 0xffff)
1225 incoming[0] = incoming[3];
1228 /* No match if the sizes don't agree. */
1230 if (insize != size) return FALSE;
1232 /* Else do the masked comparison. */
1234 for (int i = 0; i < size; i++)
1237 if (mlen == 0) mask = 0;
1240 mask = (uint)(-1) << (32 - mlen);
1248 if ((incoming[i] & mask) != (address[i] & mask)) return FALSE;
1256 /*************************************************
1257 * Scan host list for local hosts *
1258 *************************************************/
1260 /* Scan through a chain of addresses and check whether any of them is the
1261 address of an interface on the local machine. If so, remove that address and
1262 any previous ones with the same MX value, and all subsequent ones (which will
1263 have greater or equal MX values) from the chain. Note: marking them as unusable
1264 is NOT the right thing to do because it causes the hosts not to be used for
1265 other domains, for which they may well be correct.
1267 The hosts may be part of a longer chain; we only process those between the
1268 initial pointer and the "last" pointer.
1270 There is also a list of "pseudo-local" host names which are checked against the
1271 host names. Any match causes that host item to be treated the same as one which
1272 matches a local IP address.
1274 If the very first host is a local host, then all MX records had a precedence
1275 greater than or equal to that of the local host. Either there's a problem in
1276 the DNS, or an apparently remote name turned out to be an abbreviation for the
1277 local host. Give a specific return code, and let the caller decide what to do.
1278 Otherwise, give a success code if at least one host address has been found.
1281 host pointer to the first host in the chain
1282 lastptr pointer to pointer to the last host in the chain (may be updated)
1283 removed if not NULL, set TRUE if some local addresses were removed
1287 HOST_FOUND if there is at least one host with an IP address on the chain
1288 and an MX value less than any MX value associated with the
1290 HOST_FOUND_LOCAL if a local host is among the lowest-numbered MX hosts; when
1291 the host addresses were obtained from A records or
1292 gethostbyname(), the MX values are set to -1.
1293 HOST_FIND_FAILED if no valid hosts with set IP addresses were found
1297 host_scan_for_local_hosts(host_item *host, host_item **lastptr, BOOL *removed)
1299 int yield = HOST_FIND_FAILED;
1300 host_item *last = *lastptr;
1301 host_item *prev = NULL;
1304 if (removed != NULL) *removed = FALSE;
1306 if (local_interface_data == NULL) local_interface_data = host_find_interfaces();
1308 for (h = host; h != last->next; h = h->next)
1311 if (hosts_treat_as_local != NULL)
1314 const uschar *save = deliver_domain;
1315 deliver_domain = h->name; /* set $domain */
1316 rc = match_isinlist(string_copylc(h->name), CUSS &hosts_treat_as_local, 0,
1317 &domainlist_anchor, NULL, MCL_DOMAIN, TRUE, NULL);
1318 deliver_domain = save;
1319 if (rc == OK) goto FOUND_LOCAL;
1323 /* It seems that on many operating systems, 0.0.0.0 is treated as a synonym
1324 for 127.0.0.1 and refers to the local host. We therefore force it always to
1325 be treated as local. */
1327 if (h->address != NULL)
1329 if (Ustrcmp(h->address, "0.0.0.0") == 0) goto FOUND_LOCAL;
1330 for (ip_address_item * ip = local_interface_data; ip; ip = ip->next)
1331 if (Ustrcmp(h->address, ip->address) == 0) goto FOUND_LOCAL;
1332 yield = HOST_FOUND; /* At least one remote address has been found */
1335 /* Update prev to point to the last host item before any that have
1336 the same MX value as the one we have just considered. */
1338 if (h->next == NULL || h->next->mx != h->mx) prev = h;
1341 return yield; /* No local hosts found: return HOST_FOUND or HOST_FIND_FAILED */
1343 /* A host whose IP address matches a local IP address, or whose name matches
1344 something in hosts_treat_as_local has been found. */
1350 HDEBUG(D_host_lookup) debug_printf((h->mx >= 0)?
1351 "local host has lowest MX\n" :
1352 "local host found for non-MX address\n");
1353 return HOST_FOUND_LOCAL;
1356 HDEBUG(D_host_lookup)
1358 debug_printf("local host in host list - removed hosts:\n");
1359 for (h = prev->next; h != last->next; h = h->next)
1360 debug_printf(" %s %s %d\n", h->name, h->address, h->mx);
1363 if (removed != NULL) *removed = TRUE;
1364 prev->next = last->next;
1372 /*************************************************
1373 * Remove duplicate IPs in host list *
1374 *************************************************/
1376 /* You would think that administrators could set up their DNS records so that
1377 one ended up with a list of unique IP addresses after looking up A or MX
1378 records, but apparently duplication is common. So we scan such lists and
1379 remove the later duplicates. Note that we may get lists in which some host
1380 addresses are not set.
1383 host pointer to the first host in the chain
1384 lastptr pointer to pointer to the last host in the chain (may be updated)
1390 host_remove_duplicates(host_item *host, host_item **lastptr)
1392 while (host != *lastptr)
1394 if (host->address != NULL)
1396 host_item *h = host;
1397 while (h != *lastptr)
1399 if (h->next->address != NULL &&
1400 Ustrcmp(h->next->address, host->address) == 0)
1402 DEBUG(D_host_lookup) debug_printf("duplicate IP address %s (MX=%d) "
1403 "removed\n", host->address, h->next->mx);
1404 if (h->next == *lastptr) *lastptr = h;
1405 h->next = h->next->next;
1410 /* If the last item was removed, host may have become == *lastptr */
1411 if (host != *lastptr) host = host->next;
1418 /*************************************************
1419 * Find sender host name by gethostbyaddr() *
1420 *************************************************/
1422 /* This used to be the only way it was done, but it turns out that not all
1423 systems give aliases for calls to gethostbyaddr() - or one of the modern
1424 equivalents like getipnodebyaddr(). Fortunately, multiple PTR records are rare,
1425 but they can still exist. This function is now used only when a DNS lookup of
1426 the IP address fails, in order to give access to /etc/hosts.
1429 Returns: OK, DEFER, FAIL
1433 host_name_lookup_byaddr(void)
1435 struct hostent * hosts;
1436 struct in_addr addr;
1437 unsigned long time_msec = 0; /* init to quieten dumb static analysis */
1439 if (slow_lookup_log) time_msec = get_time_in_ms();
1441 /* Lookup on IPv6 system */
1444 if (Ustrchr(sender_host_address, ':') != NULL)
1446 struct in6_addr addr6;
1447 if (inet_pton(AF_INET6, CS sender_host_address, &addr6) != 1)
1448 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "unable to parse \"%s\" as an "
1449 "IPv6 address", sender_host_address);
1450 #if HAVE_GETIPNODEBYADDR
1451 hosts = getipnodebyaddr(CS &addr6, sizeof(addr6), AF_INET6, &h_errno);
1453 hosts = gethostbyaddr(CS &addr6, sizeof(addr6), AF_INET6);
1458 if (inet_pton(AF_INET, CS sender_host_address, &addr) != 1)
1459 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "unable to parse \"%s\" as an "
1460 "IPv4 address", sender_host_address);
1461 #if HAVE_GETIPNODEBYADDR
1462 hosts = getipnodebyaddr(CS &addr, sizeof(addr), AF_INET, &h_errno);
1464 hosts = gethostbyaddr(CS &addr, sizeof(addr), AF_INET);
1468 /* Do lookup on IPv4 system */
1471 addr.s_addr = (S_ADDR_TYPE)inet_addr(CS sender_host_address);
1472 hosts = gethostbyaddr(CS(&addr), sizeof(addr), AF_INET);
1475 if ( slow_lookup_log
1476 && (time_msec = get_time_in_ms() - time_msec) > slow_lookup_log
1478 log_long_lookup(US"gethostbyaddr", sender_host_address, time_msec);
1480 /* Failed to look up the host. */
1484 HDEBUG(D_host_lookup) debug_printf("IP address lookup failed: h_errno=%d\n",
1486 return (h_errno == TRY_AGAIN || h_errno == NO_RECOVERY) ? DEFER : FAIL;
1489 /* It seems there are some records in the DNS that yield an empty name. We
1490 treat this as non-existent. In some operating systems, this is returned as an
1491 empty string; in others as a single dot. */
1493 if (!hosts->h_name || !hosts->h_name[0] || hosts->h_name[0] == '.')
1495 HDEBUG(D_host_lookup) debug_printf("IP address lookup yielded an empty name: "
1496 "treated as non-existent host name\n");
1500 /* Copy and lowercase the name, which is in static storage in many systems.
1501 Put it in permanent memory. */
1504 int old_pool = store_pool;
1505 store_pool = POOL_TAINT_PERM; /* names are tainted */
1507 sender_host_name = string_copylc(US hosts->h_name);
1509 /* If the host has aliases, build a copy of the alias list */
1511 if (hosts->h_aliases)
1513 int count = 1; /* need 1 more for terminating NULL */
1516 for (uschar ** aliases = USS hosts->h_aliases; *aliases; aliases++) count++;
1517 store_pool = POOL_PERM;
1518 ptr = sender_host_aliases = store_get(count * sizeof(uschar *), GET_UNTAINTED);
1519 store_pool = POOL_TAINT_PERM;
1521 for (uschar ** aliases = USS hosts->h_aliases; *aliases; aliases++)
1522 *ptr++ = string_copylc(*aliases);
1525 store_pool = old_pool;
1533 /*************************************************
1534 * Find host name for incoming call *
1535 *************************************************/
1537 /* Put the name in permanent store, pointed to by sender_host_name. We also set
1538 up a list of alias names, pointed to by sender_host_alias. The list is
1539 NULL-terminated. The incoming address is in sender_host_address, either in
1540 dotted-quad form for IPv4 or in colon-separated form for IPv6.
1542 This function does a thorough check that the names it finds point back to the
1543 incoming IP address. Any that do not are discarded. Note that this is relied on
1544 by the ACL reverse_host_lookup check.
1546 On some systems, get{host,ipnode}byaddr() appears to do this internally, but
1547 this it not universally true. Also, for release 4.30, this function was changed
1548 to do a direct DNS lookup first, by default[1], because it turns out that that
1549 is the only guaranteed way to find all the aliases on some systems. My
1550 experiments indicate that Solaris gethostbyaddr() gives the aliases for but
1553 [1] The actual order is controlled by the host_lookup_order option.
1556 Returns: OK on success, the answer being placed in the global variable
1557 sender_host_name, with any aliases in a list hung off
1559 FAIL if no host name can be found
1560 DEFER if a temporary error was encountered
1562 The variable host_lookup_msg is set to an empty string on success, or to a
1563 reason for the failure otherwise, in a form suitable for tagging onto an error
1564 message, and also host_lookup_failed is set TRUE if the lookup failed. If there
1565 was a defer, host_lookup_deferred is set TRUE.
1567 Any dynamically constructed string for host_lookup_msg must be in permanent
1568 store, because it might be used for several incoming messages on the same SMTP
1572 host_name_lookup(void)
1576 uschar *save_hostname;
1579 const uschar *list = host_lookup_order;
1580 dns_answer * dnsa = store_get_dns_answer();
1583 sender_host_dnssec = host_lookup_deferred = host_lookup_failed = FALSE;
1585 HDEBUG(D_host_lookup)
1586 debug_printf("looking up host name for %s\n", sender_host_address);
1588 /* For testing the case when a lookup does not complete, we have a special
1589 reserved IP address. */
1591 if (f.running_in_test_harness &&
1592 Ustrcmp(sender_host_address, "99.99.99.99") == 0)
1594 HDEBUG(D_host_lookup)
1595 debug_printf("Test harness: host name lookup returns DEFER\n");
1596 host_lookup_deferred = TRUE;
1600 /* Do lookups directly in the DNS or via gethostbyaddr() (or equivalent), in
1601 the order specified by the host_lookup_order option. */
1603 while ((ordername = string_nextinlist(&list, &sep, NULL, 0)))
1605 if (strcmpic(ordername, US"bydns") == 0)
1607 uschar * name = dns_build_reverse(sender_host_address);
1609 dns_init(FALSE, FALSE, FALSE); /* dnssec ctrl by dns_dnssec_ok glbl */
1610 rc = dns_lookup_timerwrap(dnsa, name, T_PTR, NULL);
1612 /* The first record we come across is used for the name; others are
1613 considered to be aliases. We have to scan twice, in order to find out the
1614 number of aliases. However, if all the names are empty, we will behave as
1615 if failure. (PTR records that yield empty names have been encountered in
1618 if (rc == DNS_SUCCEED)
1620 uschar **aptr = NULL;
1622 int count = 1; /* need 1 more for terminating NULL */
1623 int old_pool = store_pool;
1625 sender_host_dnssec = dns_is_secure(dnsa);
1627 debug_printf("Reverse DNS security status: %s\n",
1628 sender_host_dnssec ? "DNSSEC verified (AD)" : "unverified");
1630 store_pool = POOL_PERM; /* Save names in permanent storage */
1632 for (dns_record * rr = dns_next_rr(dnsa, &dnss, RESET_ANSWERS);
1634 rr = dns_next_rr(dnsa, &dnss, RESET_NEXT)) if (rr->type == T_PTR)
1637 /* Get store for the list of aliases. For compatibility with
1638 gethostbyaddr, we make an empty list if there are none. */
1640 aptr = sender_host_aliases = store_get(count * sizeof(uschar *), GET_UNTAINTED);
1642 /* Re-scan and extract the names */
1644 for (dns_record * rr = dns_next_rr(dnsa, &dnss, RESET_ANSWERS);
1646 rr = dns_next_rr(dnsa, &dnss, RESET_NEXT)) if (rr->type == T_PTR)
1648 uschar * s = store_get(ssize, GET_TAINTED); /* names are tainted */
1651 /* If an overlong response was received, the data will have been
1652 truncated and dn_expand may fail. */
1654 if (dn_expand(dnsa->answer, dnsa->answer + dnsa->answerlen,
1655 US (rr->data), (DN_EXPAND_ARG4_TYPE)(s), ssize) < 0)
1657 log_write(0, LOG_MAIN, "host name alias list truncated for %s",
1658 sender_host_address);
1662 store_release_above(s + (slen = Ustrlen(s)) + 1);
1665 HDEBUG(D_host_lookup) debug_printf("IP address lookup yielded an "
1666 "empty name: treated as non-existent host name\n");
1669 if (Ustrspn(s, letter_digit_hyphen_dot) != slen)
1671 HDEBUG(D_host_lookup) debug_printf("IP address lookup yielded an "
1672 "illegal name (bad char): treated as non-existent host name\n");
1675 if (!sender_host_name) sender_host_name = s;
1677 while (*s) { *s = tolower(*s); s++; }
1680 *aptr = NULL; /* End of alias list */
1681 store_pool = old_pool; /* Reset store pool */
1683 /* If we've found a name, break out of the "order" loop */
1685 if (sender_host_name) break;
1688 /* If the DNS lookup deferred, we must also defer. */
1690 if (rc == DNS_AGAIN)
1692 HDEBUG(D_host_lookup)
1693 debug_printf("IP address PTR lookup gave temporary error\n");
1694 host_lookup_deferred = TRUE;
1699 /* Do a lookup using gethostbyaddr() - or equivalent */
1701 else if (strcmpic(ordername, US"byaddr") == 0)
1703 HDEBUG(D_host_lookup)
1704 debug_printf("IP address lookup using gethostbyaddr()\n");
1705 rc = host_name_lookup_byaddr();
1708 host_lookup_deferred = TRUE;
1709 return rc; /* Can't carry on */
1711 if (rc == OK) break; /* Found a name */
1713 } /* Loop for bydns/byaddr scanning */
1715 /* If we have failed to find a name, return FAIL and log when required.
1716 NB host_lookup_msg must be in permanent store. */
1718 if (!sender_host_name)
1720 if (host_checking || !f.log_testing_mode)
1721 log_write(L_host_lookup_failed, LOG_MAIN, "no host name found for IP "
1722 "address %s", sender_host_address);
1723 host_lookup_msg = US" (failed to find host name from IP address)";
1724 host_lookup_failed = TRUE;
1728 HDEBUG(D_host_lookup)
1730 uschar **aliases = sender_host_aliases;
1731 debug_printf("IP address lookup yielded \"%s\"\n", sender_host_name);
1732 while (*aliases) debug_printf(" alias \"%s\"\n", *aliases++);
1735 /* We need to verify that a forward lookup on the name we found does indeed
1736 correspond to the address. This is for security: in principle a malefactor who
1737 happened to own a reverse zone could set it to point to any names at all.
1739 This code was present in versions of Exim before 3.20. At that point I took it
1740 out because I thought that gethostbyaddr() did the check anyway. It turns out
1741 that this isn't always the case, so it's coming back in at 4.01. This version
1742 is actually better, because it also checks aliases.
1744 The code was made more robust at release 4.21. Prior to that, it accepted all
1745 the names if any of them had the correct IP address. Now the code checks all
1746 the names, and accepts only those that have the correct IP address. */
1748 save_hostname = sender_host_name; /* Save for error messages */
1749 aliases = sender_host_aliases;
1750 for (uschar * hname = sender_host_name; hname; hname = *aliases++)
1754 host_item h = { .next = NULL, .name = hname, .mx = MX_NONE, .address = NULL };
1756 { .request = sender_host_dnssec ? US"*" : NULL, .require = NULL };
1758 if ( (rc = host_find_bydns(&h, NULL, HOST_FIND_BY_A | HOST_FIND_BY_AAAA,
1759 NULL, NULL, NULL, &d, NULL, NULL)) == HOST_FOUND
1760 || rc == HOST_FOUND_LOCAL
1763 HDEBUG(D_host_lookup) debug_printf("checking addresses for %s\n", hname);
1765 /* If the forward lookup was not secure we cancel the is-secure variable */
1767 DEBUG(D_dns) debug_printf("Forward DNS security status: %s\n",
1768 h.dnssec == DS_YES ? "DNSSEC verified (AD)" : "unverified");
1769 if (h.dnssec != DS_YES) sender_host_dnssec = FALSE;
1771 for (host_item * hh = &h; hh; hh = hh->next)
1772 if (host_is_in_net(hh->address, sender_host_address, 0))
1774 HDEBUG(D_host_lookup) debug_printf(" %s OK\n", hh->address);
1779 HDEBUG(D_host_lookup) debug_printf(" %s\n", hh->address);
1781 if (!ok) HDEBUG(D_host_lookup)
1782 debug_printf("no IP address for %s matched %s\n", hname,
1783 sender_host_address);
1785 else if (rc == HOST_FIND_AGAIN)
1787 HDEBUG(D_host_lookup) debug_printf("temporary error for host name lookup\n");
1788 host_lookup_deferred = TRUE;
1789 sender_host_name = NULL;
1793 HDEBUG(D_host_lookup) debug_printf("no IP addresses found for %s\n", hname);
1795 /* If this name is no good, and it's the sender name, set it null pro tem;
1796 if it's an alias, just remove it from the list. */
1800 if (hname == sender_host_name) sender_host_name = NULL; else
1802 uschar **a; /* Don't amalgamate - some */
1803 a = --aliases; /* compilers grumble */
1804 while (*a != NULL) { *a = a[1]; a++; }
1809 /* If sender_host_name == NULL, it means we didn't like the name. Replace
1810 it with the first alias, if there is one. */
1812 if (sender_host_name == NULL && *sender_host_aliases != NULL)
1813 sender_host_name = *sender_host_aliases++;
1815 /* If we now have a main name, all is well. */
1817 if (sender_host_name != NULL) return OK;
1819 /* We have failed to find an address that matches. */
1821 HDEBUG(D_host_lookup)
1822 debug_printf("%s does not match any IP address for %s\n",
1823 sender_host_address, save_hostname);
1825 /* This message must be in permanent store */
1827 old_pool = store_pool;
1828 store_pool = POOL_PERM;
1829 host_lookup_msg = string_sprintf(" (%s does not match any IP address for %s)",
1830 sender_host_address, save_hostname);
1831 store_pool = old_pool;
1832 host_lookup_failed = TRUE;
1839 /*************************************************
1840 * Find IP address(es) for host by name *
1841 *************************************************/
1843 /* The input is a host_item structure with the name filled in and the address
1844 field set to NULL. We use gethostbyname() or getipnodebyname() or
1845 gethostbyname2(), as appropriate. Of course, these functions may use the DNS,
1846 but they do not do MX processing. It appears, however, that in some systems the
1847 current setting of resolver options is used when one of these functions calls
1848 the resolver. For this reason, we call dns_init() at the start, with arguments
1849 influenced by bits in "flags", just as we do for host_find_bydns().
1851 The second argument provides a host list (usually an IP list) of hosts to
1852 ignore. This makes it possible to ignore IPv6 link-local addresses or loopback
1853 addresses in unreasonable places.
1855 The lookup may result in a change of name. For compatibility with the dns
1856 lookup, return this via fully_qualified_name as well as updating the host item.
1857 The lookup may also yield more than one IP address, in which case chain on
1858 subsequent host_item structures.
1861 host a host item with the name and MX filled in;
1862 the address is to be filled in;
1863 multiple IP addresses cause other host items to be
1865 ignore_target_hosts a list of hosts to ignore
1866 flags HOST_FIND_QUALIFY_SINGLE ) passed to
1867 HOST_FIND_SEARCH_PARENTS ) dns_init()
1868 fully_qualified_name if not NULL, set to point to host name for
1869 compatibility with host_find_bydns
1870 local_host_check TRUE if a check for the local host is wanted
1872 Returns: HOST_FIND_FAILED Failed to find the host or domain
1873 HOST_FIND_AGAIN Try again later
1874 HOST_FOUND Host found - data filled in
1875 HOST_FOUND_LOCAL Host found and is the local host
1879 host_find_byname(host_item *host, const uschar *ignore_target_hosts, int flags,
1880 const uschar **fully_qualified_name, BOOL local_host_check)
1883 host_item *last = NULL;
1884 BOOL temp_error = FALSE;
1888 /* Copy the host name at this point to the value which is used for
1889 TLS certificate name checking, before anything modifies it. */
1891 host->certname = host->name;
1894 /* Make sure DNS options are set as required. This appears to be necessary in
1895 some circumstances when the get..byname() function actually calls the DNS. */
1897 dns_init((flags & HOST_FIND_QUALIFY_SINGLE) != 0,
1898 (flags & HOST_FIND_SEARCH_PARENTS) != 0,
1899 FALSE); /* Cannot retrieve dnssec status so do not request */
1901 /* In an IPv6 world, unless IPv6 has been disabled, we need to scan for both
1902 kinds of address, so go round the loop twice. Note that we have ensured that
1903 AF_INET6 is defined even in an IPv4 world, which makes for slightly tidier
1904 code. However, if dns_ipv4_lookup matches the domain, we also just do IPv4
1905 lookups here (except when testing standalone). */
1913 && match_isinlist(host->name, CUSS &dns_ipv4_lookup, 0,
1914 &domainlist_anchor, NULL, MCL_DOMAIN, TRUE, NULL) == OK)
1917 { af = AF_INET; times = 1; }
1919 { af = AF_INET6; times = 2; }
1921 /* No IPv6 support */
1923 #else /* HAVE_IPV6 */
1924 af = AF_INET; times = 1;
1925 #endif /* HAVE_IPV6 */
1927 /* Initialize the flag that gets set for DNS syntax check errors, so that the
1928 interface to this function can be similar to host_find_bydns. */
1930 f.host_find_failed_syntax = FALSE;
1932 /* Loop to look up both kinds of address in an IPv6 world */
1934 for (int i = 1; i <= times;
1936 af = AF_INET, /* If 2 passes, IPv4 on the second */
1942 struct hostent *hostdata;
1943 unsigned long time_msec = 0; /* compiler quietening */
1946 printf("Looking up: %s\n", host->name);
1949 if (slow_lookup_log) time_msec = get_time_in_ms();
1952 if (f.running_in_test_harness)
1953 hostdata = host_fake_gethostbyname(host->name, af, &error_num);
1956 #if HAVE_GETIPNODEBYNAME
1957 hostdata = getipnodebyname(CS host->name, af, 0, &error_num);
1959 hostdata = gethostbyname2(CS host->name, af);
1960 error_num = h_errno;
1964 #else /* not HAVE_IPV6 */
1965 if (f.running_in_test_harness)
1966 hostdata = host_fake_gethostbyname(host->name, af, &error_num);
1969 hostdata = gethostbyname(CS host->name);
1970 error_num = h_errno;
1972 #endif /* HAVE_IPV6 */
1974 if ( slow_lookup_log
1975 && (time_msec = get_time_in_ms() - time_msec) > slow_lookup_log)
1976 log_long_lookup(US"gethostbyname", host->name, time_msec);
1983 case HOST_NOT_FOUND: error = US"HOST_NOT_FOUND"; break;
1984 case TRY_AGAIN: error = US"TRY_AGAIN"; temp_error = TRUE; break;
1985 case NO_RECOVERY: error = US"NO_RECOVERY"; temp_error = TRUE; break;
1986 case NO_DATA: error = US"NO_DATA"; break;
1987 #if NO_DATA != NO_ADDRESS
1988 case NO_ADDRESS: error = US"NO_ADDRESS"; break;
1990 default: error = US"?"; break;
1993 DEBUG(D_host_lookup) debug_printf("%s(af=%s) returned %d (%s)\n",
1994 f.running_in_test_harness ? "host_fake_gethostbyname" :
1996 # if HAVE_GETIPNODEBYNAME
2004 af == AF_INET ? "inet" : "inet6", error_num, error);
2008 if (!(hostdata->h_addr_list)[0]) continue;
2010 /* Replace the name with the fully qualified one if necessary, and fill in
2011 the fully_qualified_name pointer. */
2013 if (hostdata->h_name[0] && Ustrcmp(host->name, hostdata->h_name) != 0)
2014 host->name = string_copy_dnsdomain(US hostdata->h_name);
2015 if (fully_qualified_name) *fully_qualified_name = host->name;
2017 /* Get the list of addresses. IPv4 and IPv6 addresses can be distinguished
2018 by their different lengths. Scan the list, ignoring any that are to be
2019 ignored, and build a chain from the rest. */
2021 ipv4_addr = hostdata->h_length == sizeof(struct in_addr);
2023 for (uschar ** addrlist = USS hostdata->h_addr_list; *addrlist; addrlist++)
2025 uschar *text_address =
2026 host_ntoa(ipv4_addr? AF_INET:AF_INET6, *addrlist, NULL, NULL);
2029 if ( ignore_target_hosts
2030 && verify_check_this_host(&ignore_target_hosts, NULL, host->name,
2031 text_address, NULL) == OK)
2033 DEBUG(D_host_lookup)
2034 debug_printf("ignored host %s [%s]\n", host->name, text_address);
2039 /* If this is the first address, last is NULL and we put the data in the
2044 host->address = text_address;
2045 host->port = PORT_NONE;
2046 host->status = hstatus_unknown;
2047 host->why = hwhy_unknown;
2048 host->dnssec = DS_UNK;
2052 /* Else add further host item blocks for any other addresses, keeping
2057 host_item *next = store_get(sizeof(host_item), GET_UNTAINTED);
2058 next->name = host->name;
2060 next->certname = host->certname;
2062 next->mx = host->mx;
2063 next->address = text_address;
2064 next->port = PORT_NONE;
2065 next->status = hstatus_unknown;
2066 next->why = hwhy_unknown;
2067 next->dnssec = DS_UNK;
2069 next->next = last->next;
2076 /* If no hosts were found, the address field in the original host block will be
2077 NULL. If temp_error is set, at least one of the lookups gave a temporary error,
2078 so we pass that back. */
2084 !message_id[0] && smtp_in
2085 ? string_sprintf("no IP address found for host %s (during %s)", host->name,
2086 smtp_get_connection_info()) :
2088 string_sprintf("no IP address found for host %s", host->name);
2090 HDEBUG(D_host_lookup) debug_printf("%s\n", msg);
2091 if (temp_error) goto RETURN_AGAIN;
2092 if (host_checking || !f.log_testing_mode)
2093 log_write(L_host_lookup_failed, LOG_MAIN, "%s", msg);
2094 return HOST_FIND_FAILED;
2097 /* Remove any duplicate IP addresses, then check to see if this is the local
2098 host if required. */
2100 host_remove_duplicates(host, &last);
2101 yield = local_host_check?
2102 host_scan_for_local_hosts(host, &last, NULL) : HOST_FOUND;
2104 HDEBUG(D_host_lookup)
2106 if (fully_qualified_name)
2107 debug_printf("fully qualified name = %s\n", *fully_qualified_name);
2108 debug_printf("%s looked up these IP addresses:\n",
2110 #if HAVE_GETIPNODEBYNAME
2119 for (const host_item * h = host; h != last->next; h = h->next)
2120 debug_printf(" name=%s address=%s\n", h->name,
2121 h->address ? h->address : US"<null>");
2124 /* Return the found status. */
2128 /* Handle the case when there is a temporary error. If the name matches
2129 dns_again_means_nonexist, return permanent rather than temporary failure. */
2135 const uschar *save = deliver_domain;
2136 deliver_domain = host->name; /* set $domain */
2137 rc = match_isinlist(host->name, CUSS &dns_again_means_nonexist, 0,
2138 &domainlist_anchor, NULL, MCL_DOMAIN, TRUE, NULL);
2139 deliver_domain = save;
2142 DEBUG(D_host_lookup) debug_printf("%s is in dns_again_means_nonexist: "
2143 "returning HOST_FIND_FAILED\n", host->name);
2144 return HOST_FIND_FAILED;
2147 return HOST_FIND_AGAIN;
2153 /*************************************************
2154 * Fill in a host address from the DNS *
2155 *************************************************/
2157 /* Given a host item, with its name, port and mx fields set, and its address
2158 field set to NULL, fill in its IP address from the DNS. If it is multi-homed,
2159 create additional host items for the additional addresses, copying all the
2160 other fields, and randomizing the order.
2162 On IPv6 systems, AAAA records are sought first, then A records.
2164 The host name may be changed if the DNS returns a different name - e.g. fully
2165 qualified or changed via CNAME. If fully_qualified_name is not NULL, dns_lookup
2166 ensures that it points to the fully qualified name. However, this is the fully
2167 qualified version of the original name; if a CNAME is involved, the actual
2168 canonical host name may be different again, and so we get it directly from the
2169 relevant RR. Note that we do NOT change the mx field of the host item in this
2170 function as it may be called to set the addresses of hosts taken from MX
2174 host points to the host item we're filling in
2175 lastptr points to pointer to last host item in a chain of
2176 host items (may be updated if host is last and gets
2177 extended because multihomed)
2178 ignore_target_hosts list of hosts to ignore
2179 allow_ip if TRUE, recognize an IP address and return it
2180 fully_qualified_name if not NULL, return fully qualified name here if
2181 the contents are different (i.e. it must be preset
2183 dnssec_request if TRUE request the AD bit
2184 dnssec_require if TRUE require the AD bit
2185 whichrrs select ipv4, ipv6 results
2187 Returns: HOST_FIND_FAILED couldn't find A record
2188 HOST_FIND_AGAIN try again later
2189 HOST_FIND_SECURITY dnssec required but not acheived
2190 HOST_FOUND found AAAA and/or A record(s)
2191 HOST_IGNORED found, but all IPs ignored
2195 set_address_from_dns(host_item *host, host_item **lastptr,
2196 const uschar *ignore_target_hosts, BOOL allow_ip,
2197 const uschar **fully_qualified_name,
2198 BOOL dnssec_request, BOOL dnssec_require, int whichrrs)
2200 host_item *thishostlast = NULL; /* Indicates not yet filled in anything */
2201 BOOL v6_find_again = FALSE;
2202 BOOL dnssec_fail = FALSE;
2207 /* Copy the host name at this point to the value which is used for
2208 TLS certificate name checking, before any CNAME-following modifies it. */
2210 host->certname = host->name;
2213 /* If allow_ip is set, a name which is an IP address returns that value
2214 as its address. This is used for MX records when allow_mx_to_ip is set, for
2215 those sites that feel they have to flaunt the RFC rules. */
2217 if (allow_ip && string_is_ip_address(host->name, NULL) != 0)
2220 if ( ignore_target_hosts
2221 && verify_check_this_host(&ignore_target_hosts, NULL, host->name,
2222 host->name, NULL) == OK)
2223 return HOST_IGNORED;
2226 host->address = host->name;
2230 dnsa = store_get_dns_answer();
2232 /* On an IPv6 system, unless IPv6 is disabled, go round the loop up to twice,
2233 looking for AAAA records the first time. However, unless doing standalone
2234 testing, we force an IPv4 lookup if the domain matches dns_ipv4_lookup global.
2235 On an IPv4 system, go round the loop once only, looking only for A records. */
2240 || !(whichrrs & HOST_FIND_BY_AAAA)
2242 && match_isinlist(host->name, CUSS &dns_ipv4_lookup, 0,
2243 &domainlist_anchor, NULL, MCL_DOMAIN, TRUE, NULL) == OK
2245 i = 0; /* look up A records only */
2247 #endif /* STAND_ALONE */
2249 i = 1; /* look up AAAA and A records */
2251 /* The IPv4 world */
2253 #else /* HAVE_IPV6 */
2254 i = 0; /* look up A records only */
2255 #endif /* HAVE_IPV6 */
2259 static int types[] = { T_A, T_AAAA };
2260 int type = types[i];
2261 int randoffset = i == (whichrrs & HOST_FIND_IPV4_FIRST ? 1 : 0)
2262 ? 500 : 0; /* Ensures v6/4 sort order */
2265 int rc = dns_lookup_timerwrap(dnsa, host->name, type, fully_qualified_name);
2266 lookup_dnssec_authenticated = !dnssec_request ? NULL
2267 : dns_is_secure(dnsa) ? US"yes" : US"no";
2270 if ( (dnssec_request || dnssec_require)
2271 && !dns_is_secure(dnsa)
2274 debug_printf("DNS lookup of %.256s (A/AAAA) requested AD, but got AA\n", host->name);
2276 /* We want to return HOST_FIND_AGAIN if one of the A or AAAA lookups
2277 fails or times out, but not if another one succeeds. (In the early
2278 IPv6 days there are name servers that always fail on AAAA, but are happy
2279 to give out an A record. We want to proceed with that A record.) */
2281 if (rc != DNS_SUCCEED)
2283 if (i == 0) /* Just tried for an A record, i.e. end of loop */
2285 if (host->address != NULL)
2286 i = HOST_FOUND; /* AAAA was found */
2287 else if (rc == DNS_AGAIN || rc == DNS_FAIL || v6_find_again)
2288 i = HOST_FIND_AGAIN;
2290 i = HOST_FIND_FAILED; /* DNS_NOMATCH or DNS_NODATA */
2294 /* Tried for an AAAA record: remember if this was a temporary
2295 error, and look for the next record type. */
2297 if (rc != DNS_NOMATCH && rc != DNS_NODATA) v6_find_again = TRUE;
2303 if (dns_is_secure(dnsa))
2305 DEBUG(D_host_lookup) debug_printf("%s A DNSSEC\n", host->name);
2306 if (host->dnssec == DS_UNK) /* set in host_find_bydns() */
2307 host->dnssec = DS_YES;
2314 DEBUG(D_host_lookup) debug_printf("dnssec fail on %s for %.256s",
2315 i>0 ? "AAAA" : "A", host->name);
2318 if (host->dnssec == DS_YES) /* set in host_find_bydns() */
2320 DEBUG(D_host_lookup) debug_printf("%s A cancel DNSSEC\n", host->name);
2321 host->dnssec = DS_NO;
2322 lookup_dnssec_authenticated = US"no";
2327 /* Lookup succeeded: fill in the given host item with the first non-ignored
2328 address found; create additional items for any others. A single A6 record
2329 may generate more than one address. The lookup had a chance to update the
2330 fqdn; we do not want any later times round the loop to do so. */
2332 fully_qualified_name = NULL;
2334 for (dns_record * rr = dns_next_rr(dnsa, &dnss, RESET_ANSWERS);
2336 rr = dns_next_rr(dnsa, &dnss, RESET_NEXT)) if (rr->type == type)
2338 dns_address * da = dns_address_from_rr(dnsa, rr);
2340 DEBUG(D_host_lookup)
2341 if (!da) debug_printf("no addresses extracted from A6 RR for %s\n",
2344 /* This loop runs only once for A and AAAA records, but may run
2345 several times for an A6 record that generated multiple addresses. */
2347 for (; da; da = da->next)
2350 if (ignore_target_hosts != NULL &&
2351 verify_check_this_host(&ignore_target_hosts, NULL,
2352 host->name, da->address, NULL) == OK)
2354 DEBUG(D_host_lookup)
2355 debug_printf("ignored host %s [%s]\n", host->name, da->address);
2360 /* If this is the first address, stick it in the given host block,
2361 and change the name if the returned RR has a different name. */
2363 if (thishostlast == NULL)
2365 if (strcmpic(host->name, rr->name) != 0)
2366 host->name = string_copy_dnsdomain(rr->name);
2367 host->address = da->address;
2368 host->sort_key = host->mx * 1000 + random_number(500) + randoffset;
2369 host->status = hstatus_unknown;
2370 host->why = hwhy_unknown;
2371 thishostlast = host;
2374 /* Not the first address. Check for, and ignore, duplicates. Then
2375 insert in the chain at a random point. */
2382 /* End of our local chain is specified by "thishostlast". */
2384 for (next = host;; next = next->next)
2386 if (Ustrcmp(CS da->address, next->address) == 0) break;
2387 if (next == thishostlast) { next = NULL; break; }
2389 if (next != NULL) continue; /* With loop for next address */
2391 /* Not a duplicate */
2393 new_sort_key = host->mx * 1000 + random_number(500) + randoffset;
2394 next = store_get(sizeof(host_item), GET_UNTAINTED);
2396 /* New address goes first: insert the new block after the first one
2397 (so as not to disturb the original pointer) but put the new address
2398 in the original block. */
2400 if (new_sort_key < host->sort_key)
2402 *next = *host; /* Copies port */
2404 host->address = da->address;
2405 host->sort_key = new_sort_key;
2406 if (thishostlast == host) thishostlast = next; /* Local last */
2407 if (*lastptr == host) *lastptr = next; /* Global last */
2410 /* Otherwise scan down the addresses for this host to find the
2411 one to insert after. */
2415 host_item *h = host;
2416 while (h != thishostlast)
2418 if (new_sort_key < h->next->sort_key) break;
2421 *next = *h; /* Copies port */
2423 next->address = da->address;
2424 next->sort_key = new_sort_key;
2425 if (h == thishostlast) thishostlast = next; /* Local last */
2426 if (h == *lastptr) *lastptr = next; /* Global last */
2433 /* Control gets here only if the second lookup (the A record) succeeded.
2434 However, the address may not be filled in if it was ignored. */
2439 ? HOST_FIND_SECURITY
2443 store_free_dns_answer(dnsa);
2450 /*************************************************
2451 * Find IP addresses and host names via DNS *
2452 *************************************************/
2454 /* The input is a host_item structure with the name field filled in and the
2455 address field set to NULL. This may be in a chain of other host items. The
2456 lookup may result in more than one IP address, in which case we must created
2457 new host blocks for the additional addresses, and insert them into the chain.
2458 The original name may not be fully qualified. Use the fully_qualified_name
2459 argument to return the official name, as returned by the resolver.
2462 host point to initial host item
2463 ignore_target_hosts a list of hosts to ignore
2464 whichrrs flags indicating which RRs to look for:
2465 HOST_FIND_BY_SRV => look for SRV
2466 HOST_FIND_BY_MX => look for MX
2467 HOST_FIND_BY_A => look for A
2468 HOST_FIND_BY_AAAA => look for AAAA
2469 also flags indicating how the lookup is done
2470 HOST_FIND_QUALIFY_SINGLE ) passed to the
2471 HOST_FIND_SEARCH_PARENTS ) resolver
2472 HOST_FIND_IPV4_FIRST => reverse usual result ordering
2473 HOST_FIND_IPV4_ONLY => MX results elide ipv6
2474 srv_service when SRV used, the service name
2475 srv_fail_domains DNS errors for these domains => assume nonexist
2476 mx_fail_domains DNS errors for these domains => assume nonexist
2477 dnssec_d.request => make dnssec request: domainlist
2478 dnssec_d.require => ditto and nonexist failures
2479 fully_qualified_name if not NULL, return fully-qualified name
2480 removed set TRUE if local host was removed from the list
2482 Returns: HOST_FIND_FAILED Failed to find the host or domain;
2483 if there was a syntax error,
2484 host_find_failed_syntax is set.
2485 HOST_FIND_AGAIN Could not resolve at this time
2486 HOST_FIND_SECURITY dnsssec required but not acheived
2487 HOST_FOUND Host found
2488 HOST_FOUND_LOCAL The lowest MX record points to this
2489 machine, if MX records were found, or
2490 an A record that was found contains
2491 an address of the local host
2495 host_find_bydns(host_item *host, const uschar *ignore_target_hosts, int whichrrs,
2496 uschar *srv_service, uschar *srv_fail_domains, uschar *mx_fail_domains,
2497 const dnssec_domains *dnssec_d,
2498 const uschar **fully_qualified_name, BOOL *removed)
2500 host_item *h, *last;
2504 dns_answer * dnsa = store_get_dns_answer();
2506 BOOL dnssec_require = dnssec_d
2507 && match_isinlist(host->name, CUSS &dnssec_d->require,
2508 0, &domainlist_anchor, NULL, MCL_DOMAIN, TRUE, NULL) == OK;
2509 BOOL dnssec_request = dnssec_require
2511 && match_isinlist(host->name, CUSS &dnssec_d->request,
2512 0, &domainlist_anchor, NULL, MCL_DOMAIN, TRUE, NULL) == OK);
2513 dnssec_status_t dnssec;
2515 /* Set the default fully qualified name to the incoming name, initialize the
2516 resolver if necessary, set up the relevant options, and initialize the flag
2517 that gets set for DNS syntax check errors. */
2519 if (fully_qualified_name != NULL) *fully_qualified_name = host->name;
2520 dns_init((whichrrs & HOST_FIND_QUALIFY_SINGLE) != 0,
2521 (whichrrs & HOST_FIND_SEARCH_PARENTS) != 0,
2523 f.host_find_failed_syntax = FALSE;
2525 /* First, if requested, look for SRV records. The service name is given; we
2526 assume TCP protocol. DNS domain names are constrained to a maximum of 256
2527 characters, so the code below should be safe. */
2529 if (whichrrs & HOST_FIND_BY_SRV)
2532 uschar * temp_fully_qualified_name;
2535 g = string_fmt_append(NULL, "_%s._tcp.%n%.256s",
2536 srv_service, &prefix_length, host->name);
2537 temp_fully_qualified_name = string_from_gstring(g);
2540 /* Search for SRV records. If the fully qualified name is different to
2541 the input name, pass back the new original domain, without the prepended
2545 lookup_dnssec_authenticated = NULL;
2546 rc = dns_lookup_timerwrap(dnsa, temp_fully_qualified_name, ind_type,
2547 CUSS &temp_fully_qualified_name);
2550 if ((dnssec_request || dnssec_require)
2551 && !dns_is_secure(dnsa)
2553 debug_printf("DNS lookup of %.256s (SRV) requested AD, but got AA\n", host->name);
2557 if (dns_is_secure(dnsa))
2558 { dnssec = DS_YES; lookup_dnssec_authenticated = US"yes"; }
2560 { dnssec = DS_NO; lookup_dnssec_authenticated = US"no"; }
2563 if (temp_fully_qualified_name != g->s && fully_qualified_name != NULL)
2564 *fully_qualified_name = temp_fully_qualified_name + prefix_length;
2566 /* On DNS failures, we give the "try again" error unless the domain is
2567 listed as one for which we continue. */
2569 if (rc == DNS_SUCCEED && dnssec_require && !dns_is_secure(dnsa))
2571 log_write(L_host_lookup_failed, LOG_MAIN,
2572 "dnssec fail on SRV for %.256s", host->name);
2575 if (rc == DNS_FAIL || rc == DNS_AGAIN)
2578 if (match_isinlist(host->name, CUSS &srv_fail_domains, 0,
2579 &domainlist_anchor, NULL, MCL_DOMAIN, TRUE, NULL) != OK)
2581 { yield = HOST_FIND_AGAIN; goto out; }
2582 DEBUG(D_host_lookup) debug_printf("DNS_%s treated as DNS_NODATA "
2583 "(domain in srv_fail_domains)\n", rc == DNS_FAIL ? "FAIL":"AGAIN");
2587 /* If we did not find any SRV records, search the DNS for MX records, if
2588 requested to do so. If the result is DNS_NOMATCH, it means there is no such
2589 domain, and there's no point in going on to look for address records with the
2590 same domain. The result will be DNS_NODATA if the domain exists but has no MX
2591 records. On DNS failures, we give the "try again" error unless the domain is
2592 listed as one for which we continue. */
2594 if (rc != DNS_SUCCEED && whichrrs & HOST_FIND_BY_MX)
2598 lookup_dnssec_authenticated = NULL;
2599 rc = dns_lookup_timerwrap(dnsa, host->name, ind_type, fully_qualified_name);
2602 if ( (dnssec_request || dnssec_require)
2603 && !dns_is_secure(dnsa)
2605 debug_printf("DNS lookup of %.256s (MX) requested AD, but got AA\n", host->name);
2608 if (dns_is_secure(dnsa))
2610 DEBUG(D_host_lookup) debug_printf("%s (MX resp) DNSSEC\n", host->name);
2611 dnssec = DS_YES; lookup_dnssec_authenticated = US"yes";
2615 dnssec = DS_NO; lookup_dnssec_authenticated = US"no";
2621 yield = HOST_FIND_FAILED; goto out;
2624 if (!dnssec_require || dns_is_secure(dnsa))
2626 DEBUG(D_host_lookup)
2627 debug_printf("dnssec fail on MX for %.256s", host->name);
2629 if (match_isinlist(host->name, CUSS &mx_fail_domains, 0,
2630 &domainlist_anchor, NULL, MCL_DOMAIN, TRUE, NULL) != OK)
2631 { yield = HOST_FIND_SECURITY; goto out; }
2639 if (match_isinlist(host->name, CUSS &mx_fail_domains, 0,
2640 &domainlist_anchor, NULL, MCL_DOMAIN, TRUE, NULL) != OK)
2642 { yield = HOST_FIND_AGAIN; goto out; }
2643 DEBUG(D_host_lookup) debug_printf("DNS_%s treated as DNS_NODATA "
2644 "(domain in mx_fail_domains)\n", (rc == DNS_FAIL)? "FAIL":"AGAIN");
2649 /* If we haven't found anything yet, and we are requested to do so, try for an
2650 A or AAAA record. If we find it (or them) check to see that it isn't the local
2653 if (rc != DNS_SUCCEED)
2655 if (!(whichrrs & (HOST_FIND_BY_A | HOST_FIND_BY_AAAA)))
2657 DEBUG(D_host_lookup) debug_printf("Address records are not being sought\n");
2658 yield = HOST_FIND_FAILED;
2662 last = host; /* End of local chainlet */
2664 host->port = PORT_NONE;
2665 host->dnssec = DS_UNK;
2666 lookup_dnssec_authenticated = NULL;
2667 rc = set_address_from_dns(host, &last, ignore_target_hosts, FALSE,
2668 fully_qualified_name, dnssec_request, dnssec_require, whichrrs);
2670 /* If one or more address records have been found, check that none of them
2671 are local. Since we know the host items all have their IP addresses
2672 inserted, host_scan_for_local_hosts() can only return HOST_FOUND or
2673 HOST_FOUND_LOCAL. We do not need to scan for duplicate IP addresses here,
2674 because set_address_from_dns() removes them. */
2676 if (rc == HOST_FOUND)
2677 rc = host_scan_for_local_hosts(host, &last, removed);
2679 if (rc == HOST_IGNORED) rc = HOST_FIND_FAILED; /* No special action */
2681 DEBUG(D_host_lookup)
2684 if (fully_qualified_name)
2685 debug_printf("fully qualified name = %s\n", *fully_qualified_name);
2686 for (host_item * h = host; h != last->next; h = h->next)
2687 debug_printf("%s %s mx=%d sort=%d %s\n", h->name,
2688 h->address ? h->address : US"<null>", h->mx, h->sort_key,
2689 h->status >= hstatus_unusable ? US"*" : US"");
2696 /* We have found one or more MX or SRV records. Sort them according to
2697 precedence. Put the data for the first one into the existing host block, and
2698 insert new host_item blocks into the chain for the remainder. For equal
2699 precedences one is supposed to randomize the order. To make this happen, the
2700 sorting is actually done on the MX value * 1000 + a random number. This is put
2701 into a host field called sort_key.
2703 In the case of hosts with both IPv6 and IPv4 addresses, we want to choose the
2704 IPv6 address in preference. At this stage, we don't know what kind of address
2705 the host has. We choose a random number < 500; if later we find an A record
2706 first, we add 500 to the random number. Then for any other address records, we
2707 use random numbers in the range 0-499 for AAAA records and 500-999 for A
2710 At this point we remove any duplicates that point to the same host, retaining
2711 only the one with the lowest precedence. We cannot yet check for precedence
2712 greater than that of the local host, because that test cannot be properly done
2713 until the addresses have been found - an MX record may point to a name for this
2714 host which is not the primary hostname. */
2716 last = NULL; /* Indicates that not even the first item is filled yet */
2718 for (dns_record * rr = dns_next_rr(dnsa, &dnss, RESET_ANSWERS);
2720 rr = dns_next_rr(dnsa, &dnss, RESET_NEXT)) if (rr->type == ind_type)
2722 int precedence, weight;
2723 int port = PORT_NONE;
2724 const uschar * s = rr->data; /* MUST be unsigned for GETSHORT */
2727 GETSHORT(precedence, s); /* Pointer s is advanced */
2729 /* For MX records, we use a random "weight" which causes multiple records of
2730 the same precedence to sort randomly. */
2732 if (ind_type == T_MX)
2733 weight = random_number(500);
2736 /* SRV records are specified with a port and a weight. The weight is used
2737 in a special algorithm. However, to start with, we just use it to order the
2738 records of equal priority (precedence). */
2739 GETSHORT(weight, s);
2743 /* Get the name of the host pointed to. */
2745 (void)dn_expand(dnsa->answer, dnsa->answer + dnsa->answerlen, s,
2746 (DN_EXPAND_ARG4_TYPE)data, sizeof(data));
2748 /* Check that we haven't already got this host on the chain; if we have,
2749 keep only the lower precedence. This situation shouldn't occur, but you
2750 never know what junk might get into the DNS (and this case has been seen on
2751 more than one occasion). */
2753 if (last) /* This is not the first record */
2755 host_item *prev = NULL;
2757 for (h = host; h != last->next; prev = h, h = h->next)
2758 if (strcmpic(h->name, data) == 0)
2760 DEBUG(D_host_lookup)
2761 debug_printf("discarded duplicate host %s (MX=%d)\n", data,
2762 precedence > h->mx ? precedence : h->mx);
2763 if (precedence >= h->mx) goto NEXT_MX_RR; /* Skip greater precedence */
2764 if (h == host) /* Override first item */
2767 host->sort_key = precedence * 1000 + weight;
2771 /* Unwanted host item is not the first in the chain, so we can get
2772 get rid of it by cutting it out. */
2774 prev->next = h->next;
2775 if (h == last) last = prev;
2780 /* If this is the first MX or SRV record, put the data into the existing host
2781 block. Otherwise, add a new block in the correct place; if it has to be
2782 before the first block, copy the first block's data to a new second block. */
2786 host->name = string_copy_dnsdomain(data);
2787 host->address = NULL;
2789 host->mx = precedence;
2790 host->sort_key = precedence * 1000 + weight;
2791 host->status = hstatus_unknown;
2792 host->why = hwhy_unknown;
2793 host->dnssec = dnssec;
2798 /* Make a new host item and seek the correct insertion place */
2800 int sort_key = precedence * 1000 + weight;
2801 host_item * next = store_get(sizeof(host_item), GET_UNTAINTED);
2802 next->name = string_copy_dnsdomain(data);
2803 next->address = NULL;
2805 next->mx = precedence;
2806 next->sort_key = sort_key;
2807 next->status = hstatus_unknown;
2808 next->why = hwhy_unknown;
2809 next->dnssec = dnssec;
2812 /* Handle the case when we have to insert before the first item. */
2814 if (sort_key < host->sort_key)
2821 if (last == host) last = next;
2825 /* Else scan down the items we have inserted as part of this exercise;
2826 don't go further. */
2828 for (h = host; h != last; h = h->next)
2829 if (sort_key < h->next->sort_key)
2831 next->next = h->next;
2836 /* Join on after the last host item that's part of this
2837 processing if we haven't stopped sooner. */
2841 next->next = last->next;
2848 NEXT_MX_RR: continue;
2851 if (!last) /* No rr of correct type; give up */
2853 yield = HOST_FIND_FAILED;
2857 /* If the list of hosts was obtained from SRV records, there are two things to
2858 do. First, if there is only one host, and it's name is ".", it means there is
2859 no SMTP service at this domain. Otherwise, we have to sort the hosts of equal
2860 priority according to their weights, using an algorithm that is defined in RFC
2861 2782. The hosts are currently sorted by priority and weight. For each priority
2862 group we have to pick off one host and put it first, and then repeat for any
2863 remaining in the same priority group. */
2865 if (ind_type == T_SRV)
2869 if (host == last && host->name[0] == 0)
2871 DEBUG(D_host_lookup) debug_printf("the single SRV record is \".\"\n");
2872 yield = HOST_FIND_FAILED;
2876 DEBUG(D_host_lookup)
2878 debug_printf("original ordering of hosts from SRV records:\n");
2879 for (h = host; h != last->next; h = h->next)
2880 debug_printf(" %s P=%d W=%d\n", h->name, h->mx, h->sort_key % 1000);
2883 for (pptr = &host, h = host; h != last; pptr = &h->next, h = h->next)
2888 /* Find the last following host that has the same precedence. At the same
2889 time, compute the sum of the weights and the running totals. These can be
2890 stored in the sort_key field. */
2892 for (hh = h; hh != last; hh = hh->next)
2894 int weight = hh->sort_key % 1000; /* was precedence * 1000 + weight */
2897 if (hh->mx != hh->next->mx) break;
2900 /* If there's more than one host at this precedence (priority), we need to
2901 pick one to go first. */
2907 int randomizer = random_number(sum + 1);
2909 for (ppptr = pptr, hhh = h;
2911 ppptr = &hhh->next, hhh = hhh->next)
2912 if (hhh->sort_key >= randomizer)
2915 /* hhh now points to the host that should go first; ppptr points to the
2916 place that points to it. Unfortunately, if the start of the minilist is
2917 the start of the entire list, we can't just swap the items over, because
2918 we must not change the value of host, since it is passed in from outside.
2919 One day, this could perhaps be changed.
2921 The special case is fudged by putting the new item *second* in the chain,
2922 and then transferring the data between the first and second items. We
2923 can't just swap the first and the chosen item, because that would mean
2924 that an item with zero weight might no longer be first. */
2928 *ppptr = hhh->next; /* Cuts it out of the chain */
2932 host_item temp = *h;
2935 hhh->next = temp.next;
2940 hhh->next = h; /* The rest of the chain follows it */
2941 *pptr = hhh; /* It takes the place of h */
2942 h = hhh; /* It's now the start of this minilist */
2947 /* A host has been chosen to be first at this priority and h now points
2948 to this host. There may be others at the same priority, or others at a
2949 different priority. Before we leave this host, we need to put back a sort
2950 key of the traditional MX kind, in case this host is multihomed, because
2951 the sort key is used for ordering the multiple IP addresses. We do not need
2952 to ensure that these new sort keys actually reflect the order of the hosts,
2955 h->sort_key = h->mx * 1000 + random_number(500);
2956 } /* Move on to the next host */
2959 /* Now we have to find IP addresses for all the hosts. We have ensured above
2960 that the names in all the host items are unique. Before release 4.61 we used to
2961 process records from the additional section in the DNS packet that returned the
2962 MX or SRV records. However, a DNS name server is free to drop any resource
2963 records from the additional section. In theory, this has always been a
2964 potential problem, but it is exacerbated by the advent of IPv6. If a host had
2965 several IPv4 addresses and some were not in the additional section, at least
2966 Exim would try the others. However, if a host had both IPv4 and IPv6 addresses
2967 and all the IPv4 (say) addresses were absent, Exim would try only for a IPv6
2968 connection, and never try an IPv4 address. When there was only IPv4
2969 connectivity, this was a disaster that did in practice occur.
2971 So, from release 4.61 onwards, we always search for A and AAAA records
2972 explicitly. The names shouldn't point to CNAMES, but we use the general lookup
2973 function that handles them, just in case. If any lookup gives a soft error,
2974 change the default yield.
2976 For these DNS lookups, we must disable qualify_single and search_parents;
2977 otherwise invalid host names obtained from MX or SRV records can cause trouble
2978 if they happen to match something local. */
2980 yield = HOST_FIND_FAILED; /* Default yield */
2981 dns_init(FALSE, FALSE, /* Disable qualify_single and search_parents */
2982 dnssec_request || dnssec_require);
2984 for (h = host; h != last->next; h = h->next)
2986 if (h->address) continue; /* Inserted by a multihomed host */
2988 rc = set_address_from_dns(h, &last, ignore_target_hosts, allow_mx_to_ip,
2989 NULL, dnssec_request, dnssec_require,
2990 whichrrs & HOST_FIND_IPV4_ONLY
2991 ? HOST_FIND_BY_A : HOST_FIND_BY_A | HOST_FIND_BY_AAAA);
2992 if (rc != HOST_FOUND)
2994 h->status = hstatus_unusable;
2997 case HOST_FIND_AGAIN: yield = rc; h->why = hwhy_deferred; break;
2998 case HOST_FIND_SECURITY: yield = rc; h->why = hwhy_insecure; break;
2999 case HOST_IGNORED: h->why = hwhy_ignored; break;
3000 default: h->why = hwhy_failed; break;
3005 /* Scan the list for any hosts that are marked unusable because they have
3006 been explicitly ignored, and remove them from the list, as if they did not
3007 exist. If we end up with just a single, ignored host, flatten its fields as if
3008 nothing was found. */
3010 if (ignore_target_hosts)
3012 host_item *prev = NULL;
3013 for (h = host; h != last->next; h = h->next)
3016 if (h->why != hwhy_ignored) /* Non ignored host, just continue */
3018 else if (prev == NULL) /* First host is ignored */
3020 if (h != last) /* First is not last */
3022 if (h->next == last) last = h; /* Overwrite it with next */
3023 *h = *(h->next); /* and reprocess it. */
3024 goto REDO; /* C should have redo, like Perl */
3027 else /* Ignored host is not first - */
3029 prev->next = h->next;
3030 if (h == last) last = prev;
3034 if (host->why == hwhy_ignored) host->address = NULL;
3037 /* There is still one complication in the case of IPv6. Although the code above
3038 arranges that IPv6 addresses take precedence over IPv4 addresses for multihomed
3039 hosts, it doesn't do this for addresses that apply to different hosts with the
3040 same MX precedence, because the sorting on MX precedence happens first. So we
3041 have to make another pass to check for this case. We ensure that, within a
3042 single MX preference value, IPv6 addresses come first. This can separate the
3043 addresses of a multihomed host, but that should not matter. */
3046 if (h != last && !disable_ipv6) for (h = host; h != last; h = h->next)
3049 host_item *next = h->next;
3051 if ( h->mx != next->mx /* If next is different MX */
3052 || !h->address /* OR this one is unset */
3054 continue; /* move on to next */
3056 if ( whichrrs & HOST_FIND_IPV4_FIRST
3057 ? !Ustrchr(h->address, ':') /* OR this one is IPv4 */
3059 && Ustrchr(next->address, ':') /* OR next is IPv6 */
3061 : Ustrchr(h->address, ':') /* OR this one is IPv6 */
3063 && !Ustrchr(next->address, ':') /* OR next is IPv4 */
3065 continue; /* move on to next */
3067 temp = *h; /* otherwise, swap */
3068 temp.next = next->next;
3075 /* Remove any duplicate IP addresses and then scan the list of hosts for any
3076 whose IP addresses are on the local host. If any are found, all hosts with the
3077 same or higher MX values are removed. However, if the local host has the lowest
3078 numbered MX, then HOST_FOUND_LOCAL is returned. Otherwise, if at least one host
3079 with an IP address is on the list, HOST_FOUND is returned. Otherwise,
3080 HOST_FIND_FAILED is returned, but in this case do not update the yield, as it
3081 might have been set to HOST_FIND_AGAIN just above here. If not, it will already
3082 be HOST_FIND_FAILED. */
3084 host_remove_duplicates(host, &last);
3085 rc = host_scan_for_local_hosts(host, &last, removed);
3086 if (rc != HOST_FIND_FAILED) yield = rc;
3088 DEBUG(D_host_lookup)
3090 if (fully_qualified_name)
3091 debug_printf("fully qualified name = %s\n", *fully_qualified_name);
3092 debug_printf("host_find_bydns yield = %s (%d); returned hosts:\n",
3093 yield == HOST_FOUND ? "HOST_FOUND" :
3094 yield == HOST_FOUND_LOCAL ? "HOST_FOUND_LOCAL" :
3095 yield == HOST_FIND_SECURITY ? "HOST_FIND_SECURITY" :
3096 yield == HOST_FIND_AGAIN ? "HOST_FIND_AGAIN" :
3097 yield == HOST_FIND_FAILED ? "HOST_FIND_FAILED" : "?",
3099 for (h = host; h != last->next; h = h->next)
3101 debug_printf(" %s %s MX=%d %s", h->name,
3102 !h->address ? US"<null>" : h->address, h->mx,
3103 h->dnssec == DS_YES ? US"DNSSEC " : US"");
3104 if (h->port != PORT_NONE) debug_printf("port=%d ", h->port);
3105 if (h->status >= hstatus_unusable) debug_printf("*");
3112 dns_init(FALSE, FALSE, FALSE); /* clear the dnssec bit for getaddrbyname */
3113 store_free_dns_answer(dnsa);
3121 /* Lookup TLSA record for host/port.
3122 Return: OK success with dnssec; DANE mode
3123 DEFER Do not use this host now, may retry later
3124 FAIL_FORCED No TLSA record; DANE not usable
3125 FAIL Do not use this connection
3129 tlsa_lookup(const host_item * host, dns_answer * dnsa, BOOL dane_required)
3132 const uschar * fullname = buffer;
3136 /* TLSA lookup string */
3137 (void)sprintf(CS buffer, "_%d._tcp.%.256s", host->port, host->name);
3139 rc = dns_lookup_timerwrap(dnsa, buffer, T_TLSA, &fullname);
3140 sec = dns_is_secure(dnsa);
3142 debug_printf("TLSA lookup ret %s %sDNSSEC\n", dns_rc_names[rc], sec ? "" : "not ");
3147 return DEFER; /* just defer this TLS'd conn */
3155 for (dns_record * rr = dns_next_rr(dnsa, &dnss, RESET_ANSWERS); rr;
3156 rr = dns_next_rr(dnsa, &dnss, RESET_NEXT))
3157 if (rr->type == T_TLSA && rr->size > 3)
3159 uint16_t payload_length = rr->size - 3;
3160 uschar s[MAX_TLSA_EXPANDED_SIZE], * sp = s, * p = US rr->data;
3162 sp += sprintf(CS sp, "%d ", *p++); /* usage */
3163 sp += sprintf(CS sp, "%d ", *p++); /* selector */
3164 sp += sprintf(CS sp, "%d ", *p++); /* matchtype */
3165 while (payload_length-- > 0 && sp-s < (MAX_TLSA_EXPANDED_SIZE - 4))
3166 sp += sprintf(CS sp, "%02x", *p++);
3168 debug_printf(" %s\n", s);
3173 log_write(0, LOG_MAIN,
3174 "DANE error: TLSA lookup for %s not DNSSEC", host->name);
3177 case DNS_NODATA: /* no TLSA RR for this lookup */
3178 case DNS_NOMATCH: /* no records at all for this lookup */
3179 return dane_required ? FAIL : FAIL_FORCED;
3183 return dane_required ? FAIL : DEFER;
3186 #endif /*SUPPORT_DANE*/
3190 /*************************************************
3191 **************************************************
3192 * Stand-alone test program *
3193 **************************************************
3194 *************************************************/
3198 int main(int argc, char **cargv)
3201 int whichrrs = HOST_FIND_BY_MX | HOST_FIND_BY_A | HOST_FIND_BY_AAAA;
3202 BOOL byname = FALSE;
3203 BOOL qualify_single = TRUE;
3204 BOOL search_parents = FALSE;
3205 BOOL request_dnssec = FALSE;
3206 BOOL require_dnssec = FALSE;
3207 uschar **argv = USS cargv;
3210 disable_ipv6 = FALSE;
3211 primary_hostname = US"";
3213 store_pool = POOL_MAIN;
3214 debug_selector = D_host_lookup|D_interface;
3215 debug_file = stdout;
3216 debug_fd = fileno(debug_file);
3218 printf("Exim stand-alone host functions test\n");
3220 host_find_interfaces();
3221 debug_selector = D_host_lookup | D_dns;
3223 if (argc > 1) primary_hostname = argv[1];
3225 /* So that debug level changes can be done first */
3227 dns_init(qualify_single, search_parents, FALSE);
3229 printf("Testing host lookup\n");
3231 while (Ufgets(buffer, 256, stdin) != NULL)
3234 int len = Ustrlen(buffer);
3235 uschar *fully_qualified_name;
3237 while (len > 0 && isspace(buffer[len-1])) len--;
3240 if (Ustrcmp(buffer, "q") == 0) break;
3242 if (Ustrcmp(buffer, "byname") == 0) byname = TRUE;
3243 else if (Ustrcmp(buffer, "no_byname") == 0) byname = FALSE;
3244 else if (Ustrcmp(buffer, "a_only") == 0) whichrrs = HOST_FIND_BY_A | HOST_FIND_BY_AAAA;
3245 else if (Ustrcmp(buffer, "mx_only") == 0) whichrrs = HOST_FIND_BY_MX;
3246 else if (Ustrcmp(buffer, "srv_only") == 0) whichrrs = HOST_FIND_BY_SRV;
3247 else if (Ustrcmp(buffer, "srv+a") == 0)
3248 whichrrs = HOST_FIND_BY_SRV | HOST_FIND_BY_A | HOST_FIND_BY_AAAA;
3249 else if (Ustrcmp(buffer, "srv+mx") == 0)
3250 whichrrs = HOST_FIND_BY_SRV | HOST_FIND_BY_MX;
3251 else if (Ustrcmp(buffer, "srv+mx+a") == 0)
3252 whichrrs = HOST_FIND_BY_SRV | HOST_FIND_BY_MX | HOST_FIND_BY_A | HOST_FIND_BY_AAAA;
3253 else if (Ustrcmp(buffer, "qualify_single") == 0) qualify_single = TRUE;
3254 else if (Ustrcmp(buffer, "no_qualify_single") == 0) qualify_single = FALSE;
3255 else if (Ustrcmp(buffer, "search_parents") == 0) search_parents = TRUE;
3256 else if (Ustrcmp(buffer, "no_search_parents") == 0) search_parents = FALSE;
3257 else if (Ustrcmp(buffer, "request_dnssec") == 0) request_dnssec = TRUE;
3258 else if (Ustrcmp(buffer, "no_request_dnssec") == 0) request_dnssec = FALSE;
3259 else if (Ustrcmp(buffer, "require_dnssec") == 0) require_dnssec = TRUE;
3260 else if (Ustrcmp(buffer, "no_require_dnssec") == 0) require_dnssec = FALSE;
3261 else if (Ustrcmp(buffer, "test_harness") == 0)
3262 f.running_in_test_harness = !f.running_in_test_harness;
3263 else if (Ustrcmp(buffer, "ipv6") == 0) disable_ipv6 = !disable_ipv6;
3264 else if (Ustrcmp(buffer, "res_debug") == 0)
3266 _res.options ^= RES_DEBUG;
3268 else if (Ustrncmp(buffer, "retrans", 7) == 0)
3270 (void)sscanf(CS(buffer+8), "%d", &dns_retrans);
3271 _res.retrans = dns_retrans;
3273 else if (Ustrncmp(buffer, "retry", 5) == 0)
3275 (void)sscanf(CS(buffer+6), "%d", &dns_retry);
3276 _res.retry = dns_retry;
3280 int flags = whichrrs;
3287 h.status = hstatus_unknown;
3288 h.why = hwhy_unknown;
3291 if (qualify_single) flags |= HOST_FIND_QUALIFY_SINGLE;
3292 if (search_parents) flags |= HOST_FIND_SEARCH_PARENTS;
3294 d.request = request_dnssec ? &h.name : NULL;
3295 d.require = require_dnssec ? &h.name : NULL;
3298 ? host_find_byname(&h, NULL, flags, &fully_qualified_name, TRUE)
3299 : host_find_bydns(&h, NULL, flags, US"smtp", NULL, NULL,
3300 &d, &fully_qualified_name, NULL);
3304 case HOST_FIND_FAILED: printf("Failed\n"); break;
3305 case HOST_FIND_AGAIN: printf("Again\n"); break;
3306 case HOST_FIND_SECURITY: printf("Security\n"); break;
3307 case HOST_FOUND_LOCAL: printf("Local\n"); break;
3314 printf("Testing host_aton\n");
3316 while (Ufgets(buffer, 256, stdin) != NULL)
3319 int len = Ustrlen(buffer);
3321 while (len > 0 && isspace(buffer[len-1])) len--;
3324 if (Ustrcmp(buffer, "q") == 0) break;
3326 len = host_aton(buffer, x);
3327 printf("length = %d ", len);
3328 for (int i = 0; i < len; i++)
3330 printf("%04x ", (x[i] >> 16) & 0xffff);
3331 printf("%04x ", x[i] & 0xffff);
3338 printf("Testing host_name_lookup\n");
3340 while (Ufgets(buffer, 256, stdin) != NULL)
3342 int len = Ustrlen(buffer);
3343 while (len > 0 && isspace(buffer[len-1])) len--;
3345 if (Ustrcmp(buffer, "q") == 0) break;
3346 sender_host_address = buffer;
3347 sender_host_name = NULL;
3348 sender_host_aliases = NULL;
3349 host_lookup_msg = US"";
3350 host_lookup_failed = FALSE;
3351 if (host_name_lookup() == FAIL) /* Debug causes printing */
3352 printf("Lookup failed:%s\n", host_lookup_msg);
3360 #endif /* STAND_ALONE */