1 /*************************************************
2 * Exim - an Internet mail transport agent *
3 *************************************************/
5 /* Copyright (c) University of Cambridge 1995 - 2018 */
6 /* See the file NOTICE for conditions of use and distribution. */
8 /* Functions for finding hosts, either by gethostbyname(), gethostbyaddr(), or
9 directly via the DNS. When IPv6 is supported, getipnodebyname() and
10 getipnodebyaddr() may be used instead of gethostbyname() and gethostbyaddr(),
11 if the newer functions are available. This module also contains various other
12 functions concerned with hosts and addresses, and a random number function,
13 used for randomizing hosts with equal MXs but available for use in other parts
20 /* Static variable for preserving the list of interface addresses in case it is
21 used more than once. */
23 static ip_address_item *local_interface_data = NULL;
26 #ifdef USE_INET_NTOA_FIX
27 /*************************************************
28 * Replacement for broken inet_ntoa() *
29 *************************************************/
31 /* On IRIX systems, gcc uses a different structure passing convention to the
32 native libraries. This causes inet_ntoa() to always yield 0.0.0.0 or
33 255.255.255.255. To get round this, we provide a private version of the
34 function here. It is used only if USE_INET_NTOA_FIX is set, which should happen
35 only when gcc is in use on an IRIX system. Code send to me by J.T. Breitner,
39 as seen in comp.sys.sgi.admin
41 August 2005: Apparently this is also needed for AIX systems; USE_INET_NTOA_FIX
42 should now be set for them as well.
44 Arguments: sa an in_addr structure
45 Returns: pointer to static text string
49 inet_ntoa(struct in_addr sa)
51 static uschar addr[20];
52 sprintf(addr, "%d.%d.%d.%d",
63 /*************************************************
64 * Random number generator *
65 *************************************************/
67 /* This is a simple pseudo-random number generator. It does not have to be
68 very good for the uses to which it is put. When running the regression tests,
69 start with a fixed seed.
71 If you need better, see vaguely_random_number() which is potentially stronger,
72 if a crypto library is available, but might end up just calling this instead.
75 limit: one more than the largest number required
77 Returns: a pseudo-random number in the range 0 to limit-1
81 random_number(int limit)
87 if (f.running_in_test_harness) random_seed = 42; else
89 int p = (int)getpid();
90 random_seed = (int)time(NULL) ^ ((p << 16) | p);
93 random_seed = 1103515245 * random_seed + 12345;
94 return (unsigned int)(random_seed >> 16) % limit;
97 /*************************************************
98 * Wrappers for logging lookup times *
99 *************************************************/
101 /* When the 'slow_lookup_log' variable is enabled, these wrappers will
102 write to the log file all (potential) dns lookups that take more than
103 slow_lookup_log milliseconds
107 log_long_lookup(const uschar * type, const uschar * data, unsigned long msec)
109 log_write(0, LOG_MAIN, "Long %s lookup for '%s': %lu msec",
114 /* returns the current system epoch time in milliseconds. */
118 struct timeval tmp_time;
119 unsigned long seconds, microseconds;
121 gettimeofday(&tmp_time, NULL);
122 seconds = (unsigned long) tmp_time.tv_sec;
123 microseconds = (unsigned long) tmp_time.tv_usec;
124 return seconds*1000 + microseconds/1000;
129 dns_lookup_timerwrap(dns_answer *dnsa, const uschar *name, int type,
130 const uschar **fully_qualified_name)
133 unsigned long time_msec;
135 if (!slow_lookup_log)
136 return dns_lookup(dnsa, name, type, fully_qualified_name);
138 time_msec = get_time_in_ms();
139 retval = dns_lookup(dnsa, name, type, fully_qualified_name);
140 if ((time_msec = get_time_in_ms() - time_msec) > slow_lookup_log)
141 log_long_lookup(US"name", name, time_msec);
146 /*************************************************
147 * Replace gethostbyname() when testing *
148 *************************************************/
150 /* This function is called instead of gethostbyname(), gethostbyname2(), or
151 getipnodebyname() when running in the test harness. . It also
152 recognizes an unqualified "localhost" and forces it to the appropriate loopback
153 address. IP addresses are treated as literals. For other names, it uses the DNS
154 to find the host name. In the test harness, this means it will access only the
158 name the host name or a textual IP address
159 af AF_INET or AF_INET6
160 error_num where to put an error code:
161 HOST_NOT_FOUND/TRY_AGAIN/NO_RECOVERY/NO_DATA
163 Returns: a hostent structure or NULL for an error
166 static struct hostent *
167 host_fake_gethostbyname(const uschar *name, int af, int *error_num)
170 int alen = (af == AF_INET)? sizeof(struct in_addr):sizeof(struct in6_addr);
172 int alen = sizeof(struct in_addr);
176 const uschar *lname = name;
179 struct hostent *yield;
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 ipa = string_is_ip_address(lname, NULL);
198 if ((ipa == 4 && af == AF_INET) ||
199 (ipa == 6 && af == AF_INET6))
203 yield = store_get(sizeof(struct hostent));
204 alist = store_get(2 * sizeof(char *));
205 adds = store_get(alen);
206 yield->h_name = CS name;
207 yield->h_aliases = NULL;
208 yield->h_addrtype = af;
209 yield->h_length = alen;
210 yield->h_addr_list = CSS alist;
212 n = host_aton(lname, x);
213 for (i = 0; i < n; i++)
216 *adds++ = (y >> 24) & 255;
217 *adds++ = (y >> 16) & 255;
218 *adds++ = (y >> 8) & 255;
224 /* Wrong kind of literal address */
228 *error_num = HOST_NOT_FOUND;
233 /* Handle a host name */
237 int type = (af == AF_INET)? T_A:T_AAAA;
238 int rc = dns_lookup_timerwrap(&dnsa, lname, type, NULL);
241 lookup_dnssec_authenticated = NULL;
245 case DNS_SUCCEED: break;
246 case DNS_NOMATCH: *error_num = HOST_NOT_FOUND; return NULL;
247 case DNS_NODATA: *error_num = NO_DATA; return NULL;
248 case DNS_AGAIN: *error_num = TRY_AGAIN; return NULL;
250 case DNS_FAIL: *error_num = NO_RECOVERY; return NULL;
253 for (rr = dns_next_rr(&dnsa, &dnss, RESET_ANSWERS);
255 rr = dns_next_rr(&dnsa, &dnss, RESET_NEXT))
256 if (rr->type == type)
259 yield = store_get(sizeof(struct hostent));
260 alist = store_get((count + 1) * sizeof(char *));
261 adds = store_get(count *alen);
263 yield->h_name = CS name;
264 yield->h_aliases = NULL;
265 yield->h_addrtype = af;
266 yield->h_length = alen;
267 yield->h_addr_list = CSS alist;
269 for (rr = dns_next_rr(&dnsa, &dnss, RESET_ANSWERS);
271 rr = dns_next_rr(&dnsa, &dnss, RESET_NEXT))
276 if (rr->type != type) continue;
277 if (!(da = dns_address_from_rr(&dnsa, rr))) break;
279 n = host_aton(da->address, x);
280 for (i = 0; i < n; i++)
283 *adds++ = (y >> 24) & 255;
284 *adds++ = (y >> 16) & 255;
285 *adds++ = (y >> 8) & 255;
297 /*************************************************
298 * Build chain of host items from list *
299 *************************************************/
301 /* This function builds a chain of host items from a textual list of host
302 names. It does not do any lookups. If randomize is true, the chain is build in
303 a randomized order. There may be multiple groups of independently randomized
304 hosts; they are delimited by a host name consisting of just "+".
307 anchor anchor for the chain
309 randomize TRUE for randomizing
315 host_build_hostlist(host_item **anchor, const uschar *list, BOOL randomize)
318 int fake_mx = MX_NONE; /* This value is actually -1 */
321 if (list == NULL) return;
322 if (randomize) fake_mx--; /* Start at -2 for randomizing */
326 while ((name = string_nextinlist(&list, &sep, NULL, 0)) != NULL)
330 if (name[0] == '+' && name[1] == 0) /* "+" delimits a randomized group */
331 { /* ignore if not randomizing */
332 if (randomize) fake_mx--;
336 h = store_get(sizeof(host_item));
341 h->sort_key = randomize? (-fake_mx)*1000 + random_number(1000) : 0;
342 h->status = hstatus_unknown;
343 h->why = hwhy_unknown;
353 host_item *hh = *anchor;
354 if (h->sort_key < hh->sort_key)
361 while (hh->next != NULL && h->sort_key >= (hh->next)->sort_key)
374 /*************************************************
375 * Extract port from address string *
376 *************************************************/
378 /* In the spool file, and in the -oMa and -oMi options, a host plus port is
379 given as an IP address followed by a dot and a port number. This function
382 An alternative format for the -oMa and -oMi options is [ip address]:port which
383 is what Exim 4 uses for output, because it seems to becoming commonly used,
384 whereas the dot form confuses some programs/people. So we recognize that form
388 address points to the string; if there is a port, the '.' in the string
389 is overwritten with zero to terminate the address; if the string
390 is in the [xxx]:ppp format, the address is shifted left and the
393 Returns: 0 if there is no port, else the port number. If there's a syntax
394 error, leave the incoming address alone, and return 0.
398 host_address_extract_port(uschar *address)
403 /* Handle the "bracketed with colon on the end" format */
407 uschar *rb = address + 1;
408 while (*rb != 0 && *rb != ']') rb++;
409 if (*rb++ == 0) return 0; /* Missing ]; leave invalid address */
412 port = Ustrtol(rb + 1, &endptr, 10);
413 if (*endptr != 0) return 0; /* Invalid port; leave invalid address */
415 else if (*rb != 0) return 0; /* Bad syntax; leave invalid address */
416 memmove(address, address + 1, rb - address - 2);
420 /* Handle the "dot on the end" format */
424 int skip = -3; /* Skip 3 dots in IPv4 addresses */
426 while (*(++address) != 0)
429 if (ch == ':') skip = 0; /* Skip 0 dots in IPv6 addresses */
430 else if (ch == '.' && skip++ >= 0) break;
432 if (*address == 0) return 0;
433 port = Ustrtol(address + 1, &endptr, 10);
434 if (*endptr != 0) return 0; /* Invalid port; leave invalid address */
442 /*************************************************
443 * Get port from a host item's name *
444 *************************************************/
446 /* This function is called when finding the IP address for a host that is in a
447 list of hosts explicitly configured, such as in the manualroute router, or in a
448 fallback hosts list. We see if there is a port specification at the end of the
449 host name, and if so, remove it. A minimum length of 3 is required for the
450 original name; nothing shorter is recognized as having a port.
452 We test for a name ending with a sequence of digits; if preceded by colon we
453 have a port if the character before the colon is ] and the name starts with [
454 or if there are no other colons in the name (i.e. it's not an IPv6 address).
456 Arguments: pointer to the host item
457 Returns: a port number or PORT_NONE
461 host_item_get_port(host_item *h)
465 int len = Ustrlen(h->name);
467 if (len < 3 || (p = h->name + len - 1, !isdigit(*p))) return PORT_NONE;
469 /* Extract potential port number */
474 while (p > h->name + 1 && isdigit(*p))
476 port += (*p-- - '0') * x;
480 /* The smallest value of p at this point is h->name + 1. */
482 if (*p != ':') return PORT_NONE;
484 if (p[-1] == ']' && h->name[0] == '[')
485 h->name = string_copyn(h->name + 1, p - h->name - 2);
486 else if (Ustrchr(h->name, ':') == p)
487 h->name = string_copyn(h->name, p - h->name);
488 else return PORT_NONE;
490 DEBUG(D_route|D_host_lookup) debug_printf("host=%s port=%d\n", h->name, port);
496 #ifndef STAND_ALONE /* Omit when standalone testing */
498 /*************************************************
499 * Build sender_fullhost and sender_rcvhost *
500 *************************************************/
502 /* This function is called when sender_host_name and/or sender_helo_name
503 have been set. Or might have been set - for a local message read off the spool
504 they won't be. In that case, do nothing. Otherwise, set up the fullhost string
507 (a) No sender_host_name or sender_helo_name: "[ip address]"
508 (b) Just sender_host_name: "host_name [ip address]"
509 (c) Just sender_helo_name: "(helo_name) [ip address]" unless helo is IP
510 in which case: "[ip address}"
511 (d) The two are identical: "host_name [ip address]" includes helo = IP
512 (e) The two are different: "host_name (helo_name) [ip address]"
514 If log_incoming_port is set, the sending host's port number is added to the IP
517 This function also builds sender_rcvhost for use in Received: lines, whose
518 syntax is a bit different. This value also includes the RFC 1413 identity.
519 There wouldn't be two different variables if I had got all this right in the
522 Because this data may survive over more than one incoming SMTP message, it has
523 to be in permanent store. However, STARTTLS has to be forgotten and redone
524 on a multi-message conn, so this will be called once per message then. Hence
525 we use malloc, so we can free.
532 host_build_sender_fullhost(void)
534 BOOL show_helo = TRUE;
535 uschar * address, * fullhost, * rcvhost, * reset_point;
538 if (!sender_host_address) return;
540 reset_point = store_get(0);
542 /* Set up address, with or without the port. After discussion, it seems that
543 the only format that doesn't cause trouble is [aaaa]:pppp. However, we can't
544 use this directly as the first item for Received: because it ain't an RFC 2822
547 address = string_sprintf("[%s]:%d", sender_host_address, sender_host_port);
548 if (!LOGGING(incoming_port) || sender_host_port <= 0)
549 *(Ustrrchr(address, ':')) = 0;
551 /* If there's no EHLO/HELO data, we can't show it. */
553 if (!sender_helo_name) show_helo = FALSE;
555 /* If HELO/EHLO was followed by an IP literal, it's messy because of two
556 features of IPv6. Firstly, there's the "IPv6:" prefix (Exim is liberal and
557 doesn't require this, for historical reasons). Secondly, IPv6 addresses may not
558 be given in canonical form, so we have to canonicalize them before comparing. As
559 it happens, the code works for both IPv4 and IPv6. */
561 else if (sender_helo_name[0] == '[' &&
562 sender_helo_name[(len=Ustrlen(sender_helo_name))-1] == ']')
567 if (strncmpic(sender_helo_name + 1, US"IPv6:", 5) == 0) offset += 5;
568 if (strncmpic(sender_helo_name + 1, US"IPv4:", 5) == 0) offset += 5;
570 helo_ip = string_copyn(sender_helo_name + offset, len - offset - 1);
572 if (string_is_ip_address(helo_ip, NULL) != 0)
576 uschar ipx[48], ipy[48]; /* large enough for full IPv6 */
578 sizex = host_aton(helo_ip, x);
579 sizey = host_aton(sender_host_address, y);
581 (void)host_nmtoa(sizex, x, -1, ipx, ':');
582 (void)host_nmtoa(sizey, y, -1, ipy, ':');
584 if (strcmpic(ipx, ipy) == 0) show_helo = FALSE;
588 /* Host name is not verified */
590 if (!sender_host_name)
592 uschar *portptr = Ustrstr(address, "]:");
594 int adlen; /* Sun compiler doesn't like ++ in initializers */
596 adlen = portptr ? (++portptr - address) : Ustrlen(address);
597 fullhost = sender_helo_name
598 ? string_sprintf("(%s) %s", sender_helo_name, address)
601 g = string_catn(NULL, address, adlen);
603 if (sender_ident || show_helo || portptr)
606 g = string_catn(g, US" (", 2);
610 g = string_append(g, 2, US"port=", portptr + 1);
613 g = string_append(g, 2,
614 firstptr == g->ptr ? US"helo=" : US" helo=", sender_helo_name);
617 g = string_append(g, 2,
618 firstptr == g->ptr ? US"ident=" : US" ident=", sender_ident);
620 g = string_catn(g, US")", 1);
623 rcvhost = string_from_gstring(g);
626 /* Host name is known and verified. Unless we've already found that the HELO
627 data matches the IP address, compare it with the name. */
631 if (show_helo && strcmpic(sender_host_name, sender_helo_name) == 0)
636 fullhost = string_sprintf("%s (%s) %s", sender_host_name,
637 sender_helo_name, address);
638 rcvhost = sender_ident
639 ? string_sprintf("%s\n\t(%s helo=%s ident=%s)", sender_host_name,
640 address, sender_helo_name, sender_ident)
641 : string_sprintf("%s (%s helo=%s)", sender_host_name,
642 address, sender_helo_name);
646 fullhost = string_sprintf("%s %s", sender_host_name, address);
647 rcvhost = sender_ident
648 ? string_sprintf("%s (%s ident=%s)", sender_host_name, address,
650 : string_sprintf("%s (%s)", sender_host_name, address);
654 if (sender_fullhost) store_free(sender_fullhost);
655 sender_fullhost = string_copy_malloc(fullhost);
656 if (sender_rcvhost) store_free(sender_rcvhost);
657 sender_rcvhost = string_copy_malloc(rcvhost);
659 store_reset(reset_point);
661 DEBUG(D_host_lookup) debug_printf("sender_fullhost = %s\n", sender_fullhost);
662 DEBUG(D_host_lookup) debug_printf("sender_rcvhost = %s\n", sender_rcvhost);
667 /*************************************************
668 * Build host+ident message *
669 *************************************************/
671 /* Used when logging rejections and various ACL and SMTP incidents. The text
672 return depends on whether sender_fullhost and sender_ident are set or not:
674 no ident, no host => U=unknown
675 no ident, host set => H=sender_fullhost
676 ident set, no host => U=ident
677 ident set, host set => H=sender_fullhost U=ident
680 useflag TRUE if first item to be flagged (H= or U=); if there are two
681 items, the second is always flagged
683 Returns: pointer to a string in big_buffer
687 host_and_ident(BOOL useflag)
689 if (sender_fullhost == NULL)
691 (void)string_format(big_buffer, big_buffer_size, "%s%s", useflag? "U=" : "",
692 (sender_ident == NULL)? US"unknown" : sender_ident);
696 uschar *flag = useflag? US"H=" : US"";
697 uschar *iface = US"";
698 if (LOGGING(incoming_interface) && interface_address != NULL)
699 iface = string_sprintf(" I=[%s]:%d", interface_address, interface_port);
700 if (sender_ident == NULL)
701 (void)string_format(big_buffer, big_buffer_size, "%s%s%s",
702 flag, sender_fullhost, iface);
704 (void)string_format(big_buffer, big_buffer_size, "%s%s%s U=%s",
705 flag, sender_fullhost, iface, sender_ident);
710 #endif /* STAND_ALONE */
715 /*************************************************
716 * Build list of local interfaces *
717 *************************************************/
719 /* This function interprets the contents of the local_interfaces or
720 extra_local_interfaces options, and creates an ip_address_item block for each
721 item on the list. There is no special interpretation of any IP addresses; in
722 particular, 0.0.0.0 and ::0 are returned without modification. If any address
723 includes a port, it is set in the block. Otherwise the port value is set to
728 name the name of the option being expanded
730 Returns: a chain of ip_address_items, each containing to a textual
731 version of an IP address, and a port number (host order) or
732 zero if no port was given with the address
736 host_build_ifacelist(const uschar *list, uschar *name)
740 ip_address_item * yield = NULL, * last = NULL, * next;
742 while ((s = string_nextinlist(&list, &sep, NULL, 0)))
745 int port = host_address_extract_port(s); /* Leaves just the IP address */
747 if (!(ipv = string_is_ip_address(s, NULL)))
748 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Malformed IP address \"%s\" in %s",
751 /* Skip IPv6 addresses if IPv6 is disabled. */
753 if (disable_ipv6 && ipv == 6) continue;
755 /* This use of strcpy() is OK because we have checked that s is a valid IP
756 address above. The field in the ip_address_item is large enough to hold an
759 next = store_get(sizeof(ip_address_item));
761 Ustrcpy(next->address, s);
763 next->v6_include_v4 = FALSE;
781 /*************************************************
782 * Find addresses on local interfaces *
783 *************************************************/
785 /* This function finds the addresses of local IP interfaces. These are used
786 when testing for routing to the local host. As the function may be called more
787 than once, the list is preserved in permanent store, pointed to by a static
788 variable, to save doing the work more than once per process.
790 The generic list of interfaces is obtained by calling host_build_ifacelist()
791 for local_interfaces and extra_local_interfaces. This list scanned to remove
792 duplicates (which may exist with different ports - not relevant here). If
793 either of the wildcard IP addresses (0.0.0.0 and ::0) are encountered, they are
794 replaced by the appropriate (IPv4 or IPv6) list of actual local interfaces,
795 obtained from os_find_running_interfaces().
798 Returns: a chain of ip_address_items, each containing to a textual
799 version of an IP address; the port numbers are not relevant
803 /* First, a local subfunction to add an interface to a list in permanent store,
804 but only if there isn't a previous copy of that address on the list. */
806 static ip_address_item *
807 add_unique_interface(ip_address_item *list, ip_address_item *ipa)
809 ip_address_item *ipa2;
810 for (ipa2 = list; ipa2 != NULL; ipa2 = ipa2->next)
811 if (Ustrcmp(ipa2->address, ipa->address) == 0) return list;
812 ipa2 = store_get_perm(sizeof(ip_address_item));
819 /* This is the globally visible function */
822 host_find_interfaces(void)
824 ip_address_item *running_interfaces = NULL;
826 if (local_interface_data == NULL)
828 void *reset_item = store_get(0);
829 ip_address_item *dlist = host_build_ifacelist(CUS local_interfaces,
830 US"local_interfaces");
831 ip_address_item *xlist = host_build_ifacelist(CUS extra_local_interfaces,
832 US"extra_local_interfaces");
833 ip_address_item *ipa;
835 if (dlist == NULL) dlist = xlist; else
837 for (ipa = dlist; ipa->next != NULL; ipa = ipa->next);
841 for (ipa = dlist; ipa != NULL; ipa = ipa->next)
843 if (Ustrcmp(ipa->address, "0.0.0.0") == 0 ||
844 Ustrcmp(ipa->address, "::0") == 0)
846 ip_address_item *ipa2;
847 BOOL ipv6 = ipa->address[0] == ':';
848 if (running_interfaces == NULL)
849 running_interfaces = os_find_running_interfaces();
850 for (ipa2 = running_interfaces; ipa2 != NULL; ipa2 = ipa2->next)
852 if ((Ustrchr(ipa2->address, ':') != NULL) == ipv6)
853 local_interface_data = add_unique_interface(local_interface_data,
859 local_interface_data = add_unique_interface(local_interface_data, ipa);
862 debug_printf("Configured local interface: address=%s", ipa->address);
863 if (ipa->port != 0) debug_printf(" port=%d", ipa->port);
868 store_reset(reset_item);
871 return local_interface_data;
878 /*************************************************
879 * Convert network IP address to text *
880 *************************************************/
882 /* Given an IPv4 or IPv6 address in binary, convert it to a text
883 string and return the result in a piece of new store. The address can
884 either be given directly, or passed over in a sockaddr structure. Note
885 that this isn't the converse of host_aton() because of byte ordering
886 differences. See host_nmtoa() below.
889 type if < 0 then arg points to a sockaddr, else
890 either AF_INET or AF_INET6
891 arg points to a sockaddr if type is < 0, or
892 points to an IPv4 address (32 bits), or
893 points to an IPv6 address (128 bits),
894 in both cases, in network byte order
895 buffer if NULL, the result is returned in gotten store;
896 else points to a buffer to hold the answer
897 portptr points to where to put the port number, if non NULL; only
900 Returns: pointer to character string
904 host_ntoa(int type, const void *arg, uschar *buffer, int *portptr)
908 /* The new world. It is annoying that we have to fish out the address from
909 different places in the block, depending on what kind of address it is. It
910 is also a pain that inet_ntop() returns a const uschar *, whereas the IPv4
911 function inet_ntoa() returns just uschar *, and some picky compilers insist
912 on warning if one assigns a const uschar * to a uschar *. Hence the casts. */
915 uschar addr_buffer[46];
918 int family = ((struct sockaddr *)arg)->sa_family;
919 if (family == AF_INET6)
921 struct sockaddr_in6 *sk = (struct sockaddr_in6 *)arg;
922 yield = US inet_ntop(family, &(sk->sin6_addr), CS addr_buffer,
923 sizeof(addr_buffer));
924 if (portptr != NULL) *portptr = ntohs(sk->sin6_port);
928 struct sockaddr_in *sk = (struct sockaddr_in *)arg;
929 yield = US inet_ntop(family, &(sk->sin_addr), CS addr_buffer,
930 sizeof(addr_buffer));
931 if (portptr != NULL) *portptr = ntohs(sk->sin_port);
936 yield = US inet_ntop(type, arg, CS addr_buffer, sizeof(addr_buffer));
939 /* If the result is a mapped IPv4 address, show it in V4 format. */
941 if (Ustrncmp(yield, "::ffff:", 7) == 0) yield += 7;
943 #else /* HAVE_IPV6 */
949 yield = US inet_ntoa(((struct sockaddr_in *)arg)->sin_addr);
950 if (portptr != NULL) *portptr = ntohs(((struct sockaddr_in *)arg)->sin_port);
953 yield = US inet_ntoa(*((struct in_addr *)arg));
956 /* If there is no buffer, put the string into some new store. */
958 if (buffer == NULL) return string_copy(yield);
960 /* Callers of this function with a non-NULL buffer must ensure that it is
961 large enough to hold an IPv6 address, namely, at least 46 bytes. That's what
962 makes this use of strcpy() OK. */
964 Ustrcpy(buffer, yield);
971 /*************************************************
972 * Convert address text to binary *
973 *************************************************/
975 /* Given the textual form of an IP address, convert it to binary in an
976 array of ints. IPv4 addresses occupy one int; IPv6 addresses occupy 4 ints.
977 The result has the first byte in the most significant byte of the first int. In
978 other words, the result is not in network byte order, but in host byte order.
979 As a result, this is not the converse of host_ntoa(), which expects network
980 byte order. See host_nmtoa() below.
983 address points to the textual address, checked for syntax
984 bin points to an array of 4 ints
986 Returns: the number of ints used
990 host_aton(const uschar *address, int *bin)
995 /* Handle IPv6 address, which may end with an IPv4 address. It may also end
996 with a "scope", introduced by a percent sign. This code is NOT enclosed in #if
997 HAVE_IPV6 in order that IPv6 addresses are recognized even if IPv6 is not
1000 if (Ustrchr(address, ':') != NULL)
1002 const uschar *p = address;
1003 const uschar *component[8];
1004 BOOL ipv4_ends = FALSE;
1010 /* If the address starts with a colon, it will start with two colons.
1011 Just lose the first one, which will leave a null first component. */
1015 /* Split the address into components separated by colons. The input address
1016 is supposed to be checked for syntax. There was a case where this was
1017 overlooked; to guard against that happening again, check here and crash if
1018 there are too many components. */
1020 while (*p != 0 && *p != '%')
1022 int len = Ustrcspn(p, ":%");
1023 if (len == 0) nulloffset = ci;
1024 if (ci > 7) log_write(0, LOG_MAIN|LOG_PANIC_DIE,
1025 "Internal error: invalid IPv6 address \"%s\" passed to host_aton()",
1027 component[ci++] = p;
1032 /* If the final component contains a dot, it is a trailing v4 address.
1033 As the syntax is known to be checked, just set up for a trailing
1034 v4 address and restrict the v6 part to 6 components. */
1036 if (Ustrchr(component[ci-1], '.') != NULL)
1038 address = component[--ci];
1044 /* If there are fewer than 6 or 8 components, we have to insert some
1045 more empty ones in the middle. */
1049 int insert_count = v6count - ci;
1050 for (i = v6count-1; i > nulloffset + insert_count; i--)
1051 component[i] = component[i - insert_count];
1052 while (i > nulloffset) component[i--] = US"";
1055 /* Now turn the components into binary in pairs and bung them
1056 into the vector of ints. */
1058 for (i = 0; i < v6count; i += 2)
1059 bin[i/2] = (Ustrtol(component[i], NULL, 16) << 16) +
1060 Ustrtol(component[i+1], NULL, 16);
1062 /* If there was no terminating v4 component, we are done. */
1064 if (!ipv4_ends) return 4;
1067 /* Handle IPv4 address */
1069 (void)sscanf(CS address, "%d.%d.%d.%d", x, x+1, x+2, x+3);
1070 bin[v4offset] = ((uint)x[0] << 24) + (x[1] << 16) + (x[2] << 8) + x[3];
1075 /*************************************************
1076 * Apply mask to an IP address *
1077 *************************************************/
1079 /* Mask an address held in 1 or 4 ints, with the ms bit in the ms bit of the
1083 count the number of ints
1084 binary points to the ints to be masked
1085 mask the count of ms bits to leave, or -1 if no masking
1091 host_mask(int count, int *binary, int mask)
1094 if (mask < 0) mask = 99999;
1095 for (i = 0; i < count; i++)
1098 if (mask == 0) wordmask = 0;
1101 wordmask = (uint)(-1) << (32 - mask);
1109 binary[i] &= wordmask;
1116 /*************************************************
1117 * Convert masked IP address in ints to text *
1118 *************************************************/
1120 /* We can't use host_ntoa() because it assumes the binary values are in network
1121 byte order, and these are the result of host_aton(), which puts them in ints in
1122 host byte order. Also, we really want IPv6 addresses to be in a canonical
1123 format, so we output them with no abbreviation. In a number of cases we can't
1124 use the normal colon separator in them because it terminates keys in lsearch
1125 files, so we want to use dot instead. There's an argument that specifies what
1126 to use for IPv6 addresses.
1129 count 1 or 4 (number of ints)
1130 binary points to the ints
1131 mask mask value; if < 0 don't add to result
1132 buffer big enough to hold the result
1133 sep component separator character for IPv6 addresses
1135 Returns: the number of characters placed in buffer, not counting
1140 host_nmtoa(int count, int *binary, int mask, uschar *buffer, int sep)
1143 uschar *tt = buffer;
1148 for (i = 24; i >= 0; i -= 8)
1149 tt += sprintf(CS tt, "%d.", (j >> i) & 255);
1152 for (i = 0; i < 4; i++)
1155 tt += sprintf(CS tt, "%04x%c%04x%c", (j >> 16) & 0xffff, sep, j & 0xffff, sep);
1158 tt--; /* lose final separator */
1163 tt += sprintf(CS tt, "/%d", mask);
1169 /* Like host_nmtoa() but: ipv6-only, canonical output, no mask
1172 binary points to the ints
1173 buffer big enough to hold the result
1175 Returns: the number of characters placed in buffer, not counting
1180 ipv6_nmtoa(int * binary, uschar * buffer)
1183 uschar * c = buffer;
1184 uschar * d = NULL; /* shut insufficiently "clever" compiler up */
1186 for (i = 0; i < 4; i++)
1187 { /* expand to text */
1189 c += sprintf(CS c, "%x:%x:", (j >> 16) & 0xffff, j & 0xffff);
1192 for (c = buffer, k = -1, i = 0; i < 8; i++)
1193 { /* find longest 0-group sequence */
1194 if (*c == '0') /* must be "0:" */
1198 while (c[2] == '0') i++, c += 2;
1201 k = i-j; /* length of sequence */
1202 d = s; /* start of sequence */
1205 while (*++c != ':') ;
1209 c[-1] = '\0'; /* drop trailing colon */
1211 /* debug_printf("%s: D k %d <%s> <%s>\n", __FUNCTION__, k, d, d + 2*(k+1)); */
1215 if (d == buffer) c--; /* need extra colon */
1216 *d++ = ':'; /* 1st 0 */
1217 while ((*d++ = *c++)) ;
1227 /*************************************************
1228 * Check port for tls_on_connect *
1229 *************************************************/
1231 /* This function checks whether a given incoming port is configured for tls-
1232 on-connect. It is called from the daemon and from inetd handling. If the global
1233 option tls_on_connect is already set, all ports operate this way. Otherwise, we
1234 check the tls_on_connect_ports option for a list of ports.
1236 Argument: a port number
1237 Returns: TRUE or FALSE
1241 host_is_tls_on_connect_port(int port)
1245 const uschar *list = tls_in.on_connect_ports;
1249 if (tls_in.on_connect) return TRUE;
1251 while ((s = string_nextinlist(&list, &sep, buffer, sizeof(buffer))))
1252 if (Ustrtol(s, &end, 10) == port)
1260 /*************************************************
1261 * Check whether host is in a network *
1262 *************************************************/
1264 /* This function checks whether a given IP address matches a pattern that
1265 represents either a single host, or a network (using CIDR notation). The caller
1266 of this function must check the syntax of the arguments before calling it.
1269 host string representation of the ip-address to check
1270 net string representation of the network, with optional CIDR mask
1271 maskoffset offset to the / that introduces the mask in the key
1272 zero if there is no mask
1275 TRUE the host is inside the network
1276 FALSE the host is NOT inside the network
1280 host_is_in_net(const uschar *host, const uschar *net, int maskoffset)
1286 int size = host_aton(net, address);
1289 /* No mask => all bits to be checked */
1291 if (maskoffset == 0) mlen = 99999; /* Big number */
1292 else mlen = Uatoi(net + maskoffset + 1);
1294 /* Convert the incoming address to binary. */
1296 insize = host_aton(host, incoming);
1298 /* Convert IPv4 addresses given in IPv6 compatible mode, which represent
1299 connections from IPv4 hosts to IPv6 hosts, that is, addresses of the form
1300 ::ffff:<v4address>, to IPv4 format. */
1302 if (insize == 4 && incoming[0] == 0 && incoming[1] == 0 &&
1303 incoming[2] == 0xffff)
1306 incoming[0] = incoming[3];
1309 /* No match if the sizes don't agree. */
1311 if (insize != size) return FALSE;
1313 /* Else do the masked comparison. */
1315 for (i = 0; i < size; i++)
1318 if (mlen == 0) mask = 0;
1321 mask = (uint)(-1) << (32 - mlen);
1329 if ((incoming[i] & mask) != (address[i] & mask)) return FALSE;
1337 /*************************************************
1338 * Scan host list for local hosts *
1339 *************************************************/
1341 /* Scan through a chain of addresses and check whether any of them is the
1342 address of an interface on the local machine. If so, remove that address and
1343 any previous ones with the same MX value, and all subsequent ones (which will
1344 have greater or equal MX values) from the chain. Note: marking them as unusable
1345 is NOT the right thing to do because it causes the hosts not to be used for
1346 other domains, for which they may well be correct.
1348 The hosts may be part of a longer chain; we only process those between the
1349 initial pointer and the "last" pointer.
1351 There is also a list of "pseudo-local" host names which are checked against the
1352 host names. Any match causes that host item to be treated the same as one which
1353 matches a local IP address.
1355 If the very first host is a local host, then all MX records had a precedence
1356 greater than or equal to that of the local host. Either there's a problem in
1357 the DNS, or an apparently remote name turned out to be an abbreviation for the
1358 local host. Give a specific return code, and let the caller decide what to do.
1359 Otherwise, give a success code if at least one host address has been found.
1362 host pointer to the first host in the chain
1363 lastptr pointer to pointer to the last host in the chain (may be updated)
1364 removed if not NULL, set TRUE if some local addresses were removed
1368 HOST_FOUND if there is at least one host with an IP address on the chain
1369 and an MX value less than any MX value associated with the
1371 HOST_FOUND_LOCAL if a local host is among the lowest-numbered MX hosts; when
1372 the host addresses were obtained from A records or
1373 gethostbyname(), the MX values are set to -1.
1374 HOST_FIND_FAILED if no valid hosts with set IP addresses were found
1378 host_scan_for_local_hosts(host_item *host, host_item **lastptr, BOOL *removed)
1380 int yield = HOST_FIND_FAILED;
1381 host_item *last = *lastptr;
1382 host_item *prev = NULL;
1385 if (removed != NULL) *removed = FALSE;
1387 if (local_interface_data == NULL) local_interface_data = host_find_interfaces();
1389 for (h = host; h != last->next; h = h->next)
1392 if (hosts_treat_as_local != NULL)
1395 const uschar *save = deliver_domain;
1396 deliver_domain = h->name; /* set $domain */
1397 rc = match_isinlist(string_copylc(h->name), CUSS &hosts_treat_as_local, 0,
1398 &domainlist_anchor, NULL, MCL_DOMAIN, TRUE, NULL);
1399 deliver_domain = save;
1400 if (rc == OK) goto FOUND_LOCAL;
1404 /* It seems that on many operating systems, 0.0.0.0 is treated as a synonym
1405 for 127.0.0.1 and refers to the local host. We therefore force it always to
1406 be treated as local. */
1408 if (h->address != NULL)
1410 ip_address_item *ip;
1411 if (Ustrcmp(h->address, "0.0.0.0") == 0) goto FOUND_LOCAL;
1412 for (ip = local_interface_data; ip != NULL; ip = ip->next)
1413 if (Ustrcmp(h->address, ip->address) == 0) goto FOUND_LOCAL;
1414 yield = HOST_FOUND; /* At least one remote address has been found */
1417 /* Update prev to point to the last host item before any that have
1418 the same MX value as the one we have just considered. */
1420 if (h->next == NULL || h->next->mx != h->mx) prev = h;
1423 return yield; /* No local hosts found: return HOST_FOUND or HOST_FIND_FAILED */
1425 /* A host whose IP address matches a local IP address, or whose name matches
1426 something in hosts_treat_as_local has been found. */
1432 HDEBUG(D_host_lookup) debug_printf((h->mx >= 0)?
1433 "local host has lowest MX\n" :
1434 "local host found for non-MX address\n");
1435 return HOST_FOUND_LOCAL;
1438 HDEBUG(D_host_lookup)
1440 debug_printf("local host in host list - removed hosts:\n");
1441 for (h = prev->next; h != last->next; h = h->next)
1442 debug_printf(" %s %s %d\n", h->name, h->address, h->mx);
1445 if (removed != NULL) *removed = TRUE;
1446 prev->next = last->next;
1454 /*************************************************
1455 * Remove duplicate IPs in host list *
1456 *************************************************/
1458 /* You would think that administrators could set up their DNS records so that
1459 one ended up with a list of unique IP addresses after looking up A or MX
1460 records, but apparently duplication is common. So we scan such lists and
1461 remove the later duplicates. Note that we may get lists in which some host
1462 addresses are not set.
1465 host pointer to the first host in the chain
1466 lastptr pointer to pointer to the last host in the chain (may be updated)
1472 host_remove_duplicates(host_item *host, host_item **lastptr)
1474 while (host != *lastptr)
1476 if (host->address != NULL)
1478 host_item *h = host;
1479 while (h != *lastptr)
1481 if (h->next->address != NULL &&
1482 Ustrcmp(h->next->address, host->address) == 0)
1484 DEBUG(D_host_lookup) debug_printf("duplicate IP address %s (MX=%d) "
1485 "removed\n", host->address, h->next->mx);
1486 if (h->next == *lastptr) *lastptr = h;
1487 h->next = h->next->next;
1492 /* If the last item was removed, host may have become == *lastptr */
1493 if (host != *lastptr) host = host->next;
1500 /*************************************************
1501 * Find sender host name by gethostbyaddr() *
1502 *************************************************/
1504 /* This used to be the only way it was done, but it turns out that not all
1505 systems give aliases for calls to gethostbyaddr() - or one of the modern
1506 equivalents like getipnodebyaddr(). Fortunately, multiple PTR records are rare,
1507 but they can still exist. This function is now used only when a DNS lookup of
1508 the IP address fails, in order to give access to /etc/hosts.
1511 Returns: OK, DEFER, FAIL
1515 host_name_lookup_byaddr(void)
1519 struct hostent *hosts;
1520 struct in_addr addr;
1521 unsigned long time_msec = 0; /* init to quieten dumb static analysis */
1523 if (slow_lookup_log) time_msec = get_time_in_ms();
1525 /* Lookup on IPv6 system */
1528 if (Ustrchr(sender_host_address, ':') != NULL)
1530 struct in6_addr addr6;
1531 if (inet_pton(AF_INET6, CS sender_host_address, &addr6) != 1)
1532 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "unable to parse \"%s\" as an "
1533 "IPv6 address", sender_host_address);
1534 #if HAVE_GETIPNODEBYADDR
1535 hosts = getipnodebyaddr(CS &addr6, sizeof(addr6), AF_INET6, &h_errno);
1537 hosts = gethostbyaddr(CS &addr6, sizeof(addr6), AF_INET6);
1542 if (inet_pton(AF_INET, CS sender_host_address, &addr) != 1)
1543 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "unable to parse \"%s\" as an "
1544 "IPv4 address", sender_host_address);
1545 #if HAVE_GETIPNODEBYADDR
1546 hosts = getipnodebyaddr(CS &addr, sizeof(addr), AF_INET, &h_errno);
1548 hosts = gethostbyaddr(CS &addr, sizeof(addr), AF_INET);
1552 /* Do lookup on IPv4 system */
1555 addr.s_addr = (S_ADDR_TYPE)inet_addr(CS sender_host_address);
1556 hosts = gethostbyaddr(CS(&addr), sizeof(addr), AF_INET);
1559 if ( slow_lookup_log
1560 && (time_msec = get_time_in_ms() - time_msec) > slow_lookup_log
1562 log_long_lookup(US"name", sender_host_address, time_msec);
1564 /* Failed to look up the host. */
1568 HDEBUG(D_host_lookup) debug_printf("IP address lookup failed: h_errno=%d\n",
1570 return (h_errno == TRY_AGAIN || h_errno == NO_RECOVERY) ? DEFER : FAIL;
1573 /* It seems there are some records in the DNS that yield an empty name. We
1574 treat this as non-existent. In some operating systems, this is returned as an
1575 empty string; in others as a single dot. */
1577 if (hosts->h_name == NULL || hosts->h_name[0] == 0 || hosts->h_name[0] == '.')
1579 HDEBUG(D_host_lookup) debug_printf("IP address lookup yielded an empty name: "
1580 "treated as non-existent host name\n");
1584 /* Copy and lowercase the name, which is in static storage in many systems.
1585 Put it in permanent memory. */
1587 s = US hosts->h_name;
1588 len = Ustrlen(s) + 1;
1589 t = sender_host_name = store_get_perm(len);
1590 while (*s != 0) *t++ = tolower(*s++);
1593 /* If the host has aliases, build a copy of the alias list */
1595 if (hosts->h_aliases != NULL)
1598 uschar **aliases, **ptr;
1599 for (aliases = USS hosts->h_aliases; *aliases != NULL; aliases++) count++;
1600 ptr = sender_host_aliases = store_get_perm(count * sizeof(uschar *));
1601 for (aliases = USS hosts->h_aliases; *aliases != NULL; aliases++)
1603 uschar *s = *aliases;
1604 int len = Ustrlen(s) + 1;
1605 uschar *t = *ptr++ = store_get_perm(len);
1606 while (*s != 0) *t++ = tolower(*s++);
1617 /*************************************************
1618 * Find host name for incoming call *
1619 *************************************************/
1621 /* Put the name in permanent store, pointed to by sender_host_name. We also set
1622 up a list of alias names, pointed to by sender_host_alias. The list is
1623 NULL-terminated. The incoming address is in sender_host_address, either in
1624 dotted-quad form for IPv4 or in colon-separated form for IPv6.
1626 This function does a thorough check that the names it finds point back to the
1627 incoming IP address. Any that do not are discarded. Note that this is relied on
1628 by the ACL reverse_host_lookup check.
1630 On some systems, get{host,ipnode}byaddr() appears to do this internally, but
1631 this it not universally true. Also, for release 4.30, this function was changed
1632 to do a direct DNS lookup first, by default[1], because it turns out that that
1633 is the only guaranteed way to find all the aliases on some systems. My
1634 experiments indicate that Solaris gethostbyaddr() gives the aliases for but
1637 [1] The actual order is controlled by the host_lookup_order option.
1640 Returns: OK on success, the answer being placed in the global variable
1641 sender_host_name, with any aliases in a list hung off
1643 FAIL if no host name can be found
1644 DEFER if a temporary error was encountered
1646 The variable host_lookup_msg is set to an empty string on success, or to a
1647 reason for the failure otherwise, in a form suitable for tagging onto an error
1648 message, and also host_lookup_failed is set TRUE if the lookup failed. If there
1649 was a defer, host_lookup_deferred is set TRUE.
1651 Any dynamically constructed string for host_lookup_msg must be in permanent
1652 store, because it might be used for several incoming messages on the same SMTP
1656 host_name_lookup(void)
1660 uschar *hname, *save_hostname;
1664 const uschar *list = host_lookup_order;
1669 sender_host_dnssec = host_lookup_deferred = host_lookup_failed = FALSE;
1671 HDEBUG(D_host_lookup)
1672 debug_printf("looking up host name for %s\n", sender_host_address);
1674 /* For testing the case when a lookup does not complete, we have a special
1675 reserved IP address. */
1677 if (f.running_in_test_harness &&
1678 Ustrcmp(sender_host_address, "99.99.99.99") == 0)
1680 HDEBUG(D_host_lookup)
1681 debug_printf("Test harness: host name lookup returns DEFER\n");
1682 host_lookup_deferred = TRUE;
1686 /* Do lookups directly in the DNS or via gethostbyaddr() (or equivalent), in
1687 the order specified by the host_lookup_order option. */
1689 while ((ordername = string_nextinlist(&list, &sep, buffer, sizeof(buffer))))
1691 if (strcmpic(ordername, US"bydns") == 0)
1693 dns_init(FALSE, FALSE, FALSE); /* dnssec ctrl by dns_dnssec_ok glbl */
1694 dns_build_reverse(sender_host_address, buffer);
1695 rc = dns_lookup_timerwrap(&dnsa, buffer, T_PTR, NULL);
1697 /* The first record we come across is used for the name; others are
1698 considered to be aliases. We have to scan twice, in order to find out the
1699 number of aliases. However, if all the names are empty, we will behave as
1700 if failure. (PTR records that yield empty names have been encountered in
1703 if (rc == DNS_SUCCEED)
1705 uschar **aptr = NULL;
1708 int old_pool = store_pool;
1710 sender_host_dnssec = dns_is_secure(&dnsa);
1712 debug_printf("Reverse DNS security status: %s\n",
1713 sender_host_dnssec ? "DNSSEC verified (AD)" : "unverified");
1715 store_pool = POOL_PERM; /* Save names in permanent storage */
1717 for (rr = dns_next_rr(&dnsa, &dnss, RESET_ANSWERS);
1719 rr = dns_next_rr(&dnsa, &dnss, RESET_NEXT))
1720 if (rr->type == T_PTR)
1723 /* Get store for the list of aliases. For compatibility with
1724 gethostbyaddr, we make an empty list if there are none. */
1726 aptr = sender_host_aliases = store_get(count * sizeof(uschar *));
1728 /* Re-scan and extract the names */
1730 for (rr = dns_next_rr(&dnsa, &dnss, RESET_ANSWERS);
1732 rr = dns_next_rr(&dnsa, &dnss, RESET_NEXT))
1735 if (rr->type != T_PTR) continue;
1736 s = store_get(ssize);
1738 /* If an overlong response was received, the data will have been
1739 truncated and dn_expand may fail. */
1741 if (dn_expand(dnsa.answer, dnsa.answer + dnsa.answerlen,
1742 US (rr->data), (DN_EXPAND_ARG4_TYPE)(s), ssize) < 0)
1744 log_write(0, LOG_MAIN, "host name alias list truncated for %s",
1745 sender_host_address);
1749 store_reset(s + Ustrlen(s) + 1);
1752 HDEBUG(D_host_lookup) debug_printf("IP address lookup yielded an "
1753 "empty name: treated as non-existent host name\n");
1756 if (!sender_host_name) sender_host_name = s;
1758 while (*s != 0) { *s = tolower(*s); s++; }
1761 *aptr = NULL; /* End of alias list */
1762 store_pool = old_pool; /* Reset store pool */
1764 /* If we've found a names, break out of the "order" loop */
1766 if (sender_host_name != NULL) break;
1769 /* If the DNS lookup deferred, we must also defer. */
1771 if (rc == DNS_AGAIN)
1773 HDEBUG(D_host_lookup)
1774 debug_printf("IP address PTR lookup gave temporary error\n");
1775 host_lookup_deferred = TRUE;
1780 /* Do a lookup using gethostbyaddr() - or equivalent */
1782 else if (strcmpic(ordername, US"byaddr") == 0)
1784 HDEBUG(D_host_lookup)
1785 debug_printf("IP address lookup using gethostbyaddr()\n");
1786 rc = host_name_lookup_byaddr();
1789 host_lookup_deferred = TRUE;
1790 return rc; /* Can't carry on */
1792 if (rc == OK) break; /* Found a name */
1794 } /* Loop for bydns/byaddr scanning */
1796 /* If we have failed to find a name, return FAIL and log when required.
1797 NB host_lookup_msg must be in permanent store. */
1799 if (!sender_host_name)
1801 if (host_checking || !f.log_testing_mode)
1802 log_write(L_host_lookup_failed, LOG_MAIN, "no host name found for IP "
1803 "address %s", sender_host_address);
1804 host_lookup_msg = US" (failed to find host name from IP address)";
1805 host_lookup_failed = TRUE;
1809 HDEBUG(D_host_lookup)
1811 uschar **aliases = sender_host_aliases;
1812 debug_printf("IP address lookup yielded \"%s\"\n", sender_host_name);
1813 while (*aliases != NULL) debug_printf(" alias \"%s\"\n", *aliases++);
1816 /* We need to verify that a forward lookup on the name we found does indeed
1817 correspond to the address. This is for security: in principle a malefactor who
1818 happened to own a reverse zone could set it to point to any names at all.
1820 This code was present in versions of Exim before 3.20. At that point I took it
1821 out because I thought that gethostbyaddr() did the check anyway. It turns out
1822 that this isn't always the case, so it's coming back in at 4.01. This version
1823 is actually better, because it also checks aliases.
1825 The code was made more robust at release 4.21. Prior to that, it accepted all
1826 the names if any of them had the correct IP address. Now the code checks all
1827 the names, and accepts only those that have the correct IP address. */
1829 save_hostname = sender_host_name; /* Save for error messages */
1830 aliases = sender_host_aliases;
1831 for (hname = sender_host_name; hname; hname = *aliases++)
1835 host_item h = { .next = NULL, .name = hname, .mx = MX_NONE, .address = NULL };
1837 { .request = sender_host_dnssec ? US"*" : NULL, .require = NULL };
1839 if ( (rc = host_find_bydns(&h, NULL, HOST_FIND_BY_A | HOST_FIND_BY_AAAA,
1840 NULL, NULL, NULL, &d, NULL, NULL)) == HOST_FOUND
1841 || rc == HOST_FOUND_LOCAL
1845 HDEBUG(D_host_lookup) debug_printf("checking addresses for %s\n", hname);
1847 /* If the forward lookup was not secure we cancel the is-secure variable */
1849 DEBUG(D_dns) debug_printf("Forward DNS security status: %s\n",
1850 h.dnssec == DS_YES ? "DNSSEC verified (AD)" : "unverified");
1851 if (h.dnssec != DS_YES) sender_host_dnssec = FALSE;
1853 for (hh = &h; hh; hh = hh->next)
1854 if (host_is_in_net(hh->address, sender_host_address, 0))
1856 HDEBUG(D_host_lookup) debug_printf(" %s OK\n", hh->address);
1861 HDEBUG(D_host_lookup) debug_printf(" %s\n", hh->address);
1863 if (!ok) HDEBUG(D_host_lookup)
1864 debug_printf("no IP address for %s matched %s\n", hname,
1865 sender_host_address);
1867 else if (rc == HOST_FIND_AGAIN)
1869 HDEBUG(D_host_lookup) debug_printf("temporary error for host name lookup\n");
1870 host_lookup_deferred = TRUE;
1871 sender_host_name = NULL;
1875 HDEBUG(D_host_lookup) debug_printf("no IP addresses found for %s\n", hname);
1877 /* If this name is no good, and it's the sender name, set it null pro tem;
1878 if it's an alias, just remove it from the list. */
1882 if (hname == sender_host_name) sender_host_name = NULL; else
1884 uschar **a; /* Don't amalgamate - some */
1885 a = --aliases; /* compilers grumble */
1886 while (*a != NULL) { *a = a[1]; a++; }
1891 /* If sender_host_name == NULL, it means we didn't like the name. Replace
1892 it with the first alias, if there is one. */
1894 if (sender_host_name == NULL && *sender_host_aliases != NULL)
1895 sender_host_name = *sender_host_aliases++;
1897 /* If we now have a main name, all is well. */
1899 if (sender_host_name != NULL) return OK;
1901 /* We have failed to find an address that matches. */
1903 HDEBUG(D_host_lookup)
1904 debug_printf("%s does not match any IP address for %s\n",
1905 sender_host_address, save_hostname);
1907 /* This message must be in permanent store */
1909 old_pool = store_pool;
1910 store_pool = POOL_PERM;
1911 host_lookup_msg = string_sprintf(" (%s does not match any IP address for %s)",
1912 sender_host_address, save_hostname);
1913 store_pool = old_pool;
1914 host_lookup_failed = TRUE;
1921 /*************************************************
1922 * Find IP address(es) for host by name *
1923 *************************************************/
1925 /* The input is a host_item structure with the name filled in and the address
1926 field set to NULL. We use gethostbyname() or getipnodebyname() or
1927 gethostbyname2(), as appropriate. Of course, these functions may use the DNS,
1928 but they do not do MX processing. It appears, however, that in some systems the
1929 current setting of resolver options is used when one of these functions calls
1930 the resolver. For this reason, we call dns_init() at the start, with arguments
1931 influenced by bits in "flags", just as we do for host_find_bydns().
1933 The second argument provides a host list (usually an IP list) of hosts to
1934 ignore. This makes it possible to ignore IPv6 link-local addresses or loopback
1935 addresses in unreasonable places.
1937 The lookup may result in a change of name. For compatibility with the dns
1938 lookup, return this via fully_qualified_name as well as updating the host item.
1939 The lookup may also yield more than one IP address, in which case chain on
1940 subsequent host_item structures.
1943 host a host item with the name and MX filled in;
1944 the address is to be filled in;
1945 multiple IP addresses cause other host items to be
1947 ignore_target_hosts a list of hosts to ignore
1948 flags HOST_FIND_QUALIFY_SINGLE ) passed to
1949 HOST_FIND_SEARCH_PARENTS ) dns_init()
1950 fully_qualified_name if not NULL, set to point to host name for
1951 compatibility with host_find_bydns
1952 local_host_check TRUE if a check for the local host is wanted
1954 Returns: HOST_FIND_FAILED Failed to find the host or domain
1955 HOST_FIND_AGAIN Try again later
1956 HOST_FOUND Host found - data filled in
1957 HOST_FOUND_LOCAL Host found and is the local host
1961 host_find_byname(host_item *host, const uschar *ignore_target_hosts, int flags,
1962 const uschar **fully_qualified_name, BOOL local_host_check)
1964 int i, yield, times;
1966 host_item *last = NULL;
1967 BOOL temp_error = FALSE;
1972 /* Make sure DNS options are set as required. This appears to be necessary in
1973 some circumstances when the get..byname() function actually calls the DNS. */
1975 dns_init((flags & HOST_FIND_QUALIFY_SINGLE) != 0,
1976 (flags & HOST_FIND_SEARCH_PARENTS) != 0,
1977 FALSE); /* Cannot retrieve dnssec status so do not request */
1979 /* In an IPv6 world, unless IPv6 has been disabled, we need to scan for both
1980 kinds of address, so go round the loop twice. Note that we have ensured that
1981 AF_INET6 is defined even in an IPv4 world, which makes for slightly tidier
1982 code. However, if dns_ipv4_lookup matches the domain, we also just do IPv4
1983 lookups here (except when testing standalone). */
1990 (dns_ipv4_lookup != NULL &&
1991 match_isinlist(host->name, CUSS &dns_ipv4_lookup, 0, NULL, NULL,
1992 MCL_DOMAIN, TRUE, NULL) == OK))
1995 { af = AF_INET; times = 1; }
1997 { af = AF_INET6; times = 2; }
1999 /* No IPv6 support */
2001 #else /* HAVE_IPV6 */
2003 #endif /* HAVE_IPV6 */
2005 /* Initialize the flag that gets set for DNS syntax check errors, so that the
2006 interface to this function can be similar to host_find_bydns. */
2008 f.host_find_failed_syntax = FALSE;
2010 /* Loop to look up both kinds of address in an IPv6 world */
2012 for (i = 1; i <= times;
2014 af = AF_INET, /* If 2 passes, IPv4 on the second */
2020 struct hostent *hostdata;
2021 unsigned long time_msec = 0; /* compiler quietening */
2024 printf("Looking up: %s\n", host->name);
2027 if (slow_lookup_log) time_msec = get_time_in_ms();
2030 if (f.running_in_test_harness)
2031 hostdata = host_fake_gethostbyname(host->name, af, &error_num);
2034 #if HAVE_GETIPNODEBYNAME
2035 hostdata = getipnodebyname(CS host->name, af, 0, &error_num);
2037 hostdata = gethostbyname2(CS host->name, af);
2038 error_num = h_errno;
2042 #else /* not HAVE_IPV6 */
2043 if (f.running_in_test_harness)
2044 hostdata = host_fake_gethostbyname(host->name, AF_INET, &error_num);
2047 hostdata = gethostbyname(CS host->name);
2048 error_num = h_errno;
2050 #endif /* HAVE_IPV6 */
2052 if ( slow_lookup_log
2053 && (time_msec = get_time_in_ms() - time_msec) > slow_lookup_log)
2054 log_long_lookup(US"name", host->name, time_msec);
2056 if (hostdata == NULL)
2061 case HOST_NOT_FOUND: error = US"HOST_NOT_FOUND"; break;
2062 case TRY_AGAIN: error = US"TRY_AGAIN"; break;
2063 case NO_RECOVERY: error = US"NO_RECOVERY"; break;
2064 case NO_DATA: error = US"NO_DATA"; break;
2065 #if NO_DATA != NO_ADDRESS
2066 case NO_ADDRESS: error = US"NO_ADDRESS"; break;
2068 default: error = US"?"; break;
2071 DEBUG(D_host_lookup) debug_printf("%s returned %d (%s)\n",
2073 #if HAVE_GETIPNODEBYNAME
2074 (af == AF_INET6)? "getipnodebyname(af=inet6)" : "getipnodebyname(af=inet)",
2076 (af == AF_INET6)? "gethostbyname2(af=inet6)" : "gethostbyname2(af=inet)",
2083 if (error_num == TRY_AGAIN || error_num == NO_RECOVERY) temp_error = TRUE;
2086 if ((hostdata->h_addr_list)[0] == NULL) continue;
2088 /* Replace the name with the fully qualified one if necessary, and fill in
2089 the fully_qualified_name pointer. */
2091 if (hostdata->h_name[0] != 0 &&
2092 Ustrcmp(host->name, hostdata->h_name) != 0)
2093 host->name = string_copy_dnsdomain(US hostdata->h_name);
2094 if (fully_qualified_name != NULL) *fully_qualified_name = host->name;
2096 /* Get the list of addresses. IPv4 and IPv6 addresses can be distinguished
2097 by their different lengths. Scan the list, ignoring any that are to be
2098 ignored, and build a chain from the rest. */
2100 ipv4_addr = hostdata->h_length == sizeof(struct in_addr);
2102 for (addrlist = USS hostdata->h_addr_list; *addrlist != NULL; addrlist++)
2104 uschar *text_address =
2105 host_ntoa(ipv4_addr? AF_INET:AF_INET6, *addrlist, NULL, NULL);
2108 if (ignore_target_hosts != NULL &&
2109 verify_check_this_host(&ignore_target_hosts, NULL, host->name,
2110 text_address, NULL) == OK)
2112 DEBUG(D_host_lookup)
2113 debug_printf("ignored host %s [%s]\n", host->name, text_address);
2118 /* If this is the first address, last == NULL and we put the data in the
2123 host->address = text_address;
2124 host->port = PORT_NONE;
2125 host->status = hstatus_unknown;
2126 host->why = hwhy_unknown;
2127 host->dnssec = DS_UNK;
2131 /* Else add further host item blocks for any other addresses, keeping
2136 host_item *next = store_get(sizeof(host_item));
2137 next->name = host->name;
2138 next->mx = host->mx;
2139 next->address = text_address;
2140 next->port = PORT_NONE;
2141 next->status = hstatus_unknown;
2142 next->why = hwhy_unknown;
2143 next->dnssec = DS_UNK;
2145 next->next = last->next;
2152 /* If no hosts were found, the address field in the original host block will be
2153 NULL. If temp_error is set, at least one of the lookups gave a temporary error,
2154 so we pass that back. */
2156 if (host->address == NULL)
2160 (message_id[0] == 0 && smtp_in != NULL)?
2161 string_sprintf("no IP address found for host %s (during %s)", host->name,
2162 smtp_get_connection_info()) :
2164 string_sprintf("no IP address found for host %s", host->name);
2166 HDEBUG(D_host_lookup) debug_printf("%s\n", msg);
2167 if (temp_error) goto RETURN_AGAIN;
2168 if (host_checking || !f.log_testing_mode)
2169 log_write(L_host_lookup_failed, LOG_MAIN, "%s", msg);
2170 return HOST_FIND_FAILED;
2173 /* Remove any duplicate IP addresses, then check to see if this is the local
2174 host if required. */
2176 host_remove_duplicates(host, &last);
2177 yield = local_host_check?
2178 host_scan_for_local_hosts(host, &last, NULL) : HOST_FOUND;
2180 HDEBUG(D_host_lookup)
2183 if (fully_qualified_name != NULL)
2184 debug_printf("fully qualified name = %s\n", *fully_qualified_name);
2185 debug_printf("%s looked up these IP addresses:\n",
2187 #if HAVE_GETIPNODEBYNAME
2196 for (h = host; h != last->next; h = h->next)
2197 debug_printf(" name=%s address=%s\n", h->name,
2198 (h->address == NULL)? US"<null>" : h->address);
2201 /* Return the found status. */
2205 /* Handle the case when there is a temporary error. If the name matches
2206 dns_again_means_nonexist, return permanent rather than temporary failure. */
2212 const uschar *save = deliver_domain;
2213 deliver_domain = host->name; /* set $domain */
2214 rc = match_isinlist(host->name, CUSS &dns_again_means_nonexist, 0, NULL, NULL,
2215 MCL_DOMAIN, TRUE, NULL);
2216 deliver_domain = save;
2219 DEBUG(D_host_lookup) debug_printf("%s is in dns_again_means_nonexist: "
2220 "returning HOST_FIND_FAILED\n", host->name);
2221 return HOST_FIND_FAILED;
2224 return HOST_FIND_AGAIN;
2230 /*************************************************
2231 * Fill in a host address from the DNS *
2232 *************************************************/
2234 /* Given a host item, with its name, port and mx fields set, and its address
2235 field set to NULL, fill in its IP address from the DNS. If it is multi-homed,
2236 create additional host items for the additional addresses, copying all the
2237 other fields, and randomizing the order.
2239 On IPv6 systems, AAAA records are sought first, then A records.
2241 The host name may be changed if the DNS returns a different name - e.g. fully
2242 qualified or changed via CNAME. If fully_qualified_name is not NULL, dns_lookup
2243 ensures that it points to the fully qualified name. However, this is the fully
2244 qualified version of the original name; if a CNAME is involved, the actual
2245 canonical host name may be different again, and so we get it directly from the
2246 relevant RR. Note that we do NOT change the mx field of the host item in this
2247 function as it may be called to set the addresses of hosts taken from MX
2251 host points to the host item we're filling in
2252 lastptr points to pointer to last host item in a chain of
2253 host items (may be updated if host is last and gets
2254 extended because multihomed)
2255 ignore_target_hosts list of hosts to ignore
2256 allow_ip if TRUE, recognize an IP address and return it
2257 fully_qualified_name if not NULL, return fully qualified name here if
2258 the contents are different (i.e. it must be preset
2260 dnssec_request if TRUE request the AD bit
2261 dnssec_require if TRUE require the AD bit
2262 whichrrs select ipv4, ipv6 results
2264 Returns: HOST_FIND_FAILED couldn't find A record
2265 HOST_FIND_AGAIN try again later
2266 HOST_FIND_SECURITY dnssec required but not acheived
2267 HOST_FOUND found AAAA and/or A record(s)
2268 HOST_IGNORED found, but all IPs ignored
2272 set_address_from_dns(host_item *host, host_item **lastptr,
2273 const uschar *ignore_target_hosts, BOOL allow_ip,
2274 const uschar **fully_qualified_name,
2275 BOOL dnssec_request, BOOL dnssec_require, int whichrrs)
2278 host_item *thishostlast = NULL; /* Indicates not yet filled in anything */
2279 BOOL v6_find_again = FALSE;
2280 BOOL dnssec_fail = FALSE;
2283 /* If allow_ip is set, a name which is an IP address returns that value
2284 as its address. This is used for MX records when allow_mx_to_ip is set, for
2285 those sites that feel they have to flaunt the RFC rules. */
2287 if (allow_ip && string_is_ip_address(host->name, NULL) != 0)
2290 if ( ignore_target_hosts
2291 && verify_check_this_host(&ignore_target_hosts, NULL, host->name,
2292 host->name, NULL) == OK)
2293 return HOST_IGNORED;
2296 host->address = host->name;
2300 /* On an IPv6 system, unless IPv6 is disabled, go round the loop up to twice,
2301 looking for AAAA records the first time. However, unless doing standalone
2302 testing, we force an IPv4 lookup if the domain matches dns_ipv4_lookup global.
2303 On an IPv4 system, go round the loop once only, looking only for A records. */
2308 || !(whichrrs & HOST_FIND_BY_AAAA)
2310 && match_isinlist(host->name, CUSS &dns_ipv4_lookup, 0, NULL, NULL,
2311 MCL_DOMAIN, TRUE, NULL) == OK)
2313 i = 0; /* look up A records only */
2315 #endif /* STAND_ALONE */
2317 i = 1; /* look up AAAA and A records */
2319 /* The IPv4 world */
2321 #else /* HAVE_IPV6 */
2322 i = 0; /* look up A records only */
2323 #endif /* HAVE_IPV6 */
2327 static int types[] = { T_A, T_AAAA };
2328 int type = types[i];
2329 int randoffset = i == (whichrrs & HOST_FIND_IPV4_FIRST ? 1 : 0)
2330 ? 500 : 0; /* Ensures v6/4 sort order */
2334 int rc = dns_lookup_timerwrap(&dnsa, host->name, type, fully_qualified_name);
2335 lookup_dnssec_authenticated = !dnssec_request ? NULL
2336 : dns_is_secure(&dnsa) ? US"yes" : US"no";
2339 if ( (dnssec_request || dnssec_require)
2340 && !dns_is_secure(&dnsa)
2343 debug_printf("DNS lookup of %.256s (A/AAAA) requested AD, but got AA\n", host->name);
2345 /* We want to return HOST_FIND_AGAIN if one of the A or AAAA lookups
2346 fails or times out, but not if another one succeeds. (In the early
2347 IPv6 days there are name servers that always fail on AAAA, but are happy
2348 to give out an A record. We want to proceed with that A record.) */
2350 if (rc != DNS_SUCCEED)
2352 if (i == 0) /* Just tried for an A record, i.e. end of loop */
2354 if (host->address != NULL) return HOST_FOUND; /* AAAA was found */
2355 if (rc == DNS_AGAIN || rc == DNS_FAIL || v6_find_again)
2356 return HOST_FIND_AGAIN;
2357 return HOST_FIND_FAILED; /* DNS_NOMATCH or DNS_NODATA */
2360 /* Tried for an AAAA record: remember if this was a temporary
2361 error, and look for the next record type. */
2363 if (rc != DNS_NOMATCH && rc != DNS_NODATA) v6_find_again = TRUE;
2369 if (dns_is_secure(&dnsa))
2371 DEBUG(D_host_lookup) debug_printf("%s A DNSSEC\n", host->name);
2372 if (host->dnssec == DS_UNK) /* set in host_find_bydns() */
2373 host->dnssec = DS_YES;
2380 DEBUG(D_host_lookup) debug_printf("dnssec fail on %s for %.256s",
2381 i>0 ? "AAAA" : "A", host->name);
2384 if (host->dnssec == DS_YES) /* set in host_find_bydns() */
2386 DEBUG(D_host_lookup) debug_printf("%s A cancel DNSSEC\n", host->name);
2387 host->dnssec = DS_NO;
2388 lookup_dnssec_authenticated = US"no";
2393 /* Lookup succeeded: fill in the given host item with the first non-ignored
2394 address found; create additional items for any others. A single A6 record
2395 may generate more than one address. The lookup had a chance to update the
2396 fqdn; we do not want any later times round the loop to do so. */
2398 fully_qualified_name = NULL;
2400 for (rr = dns_next_rr(&dnsa, &dnss, RESET_ANSWERS);
2402 rr = dns_next_rr(&dnsa, &dnss, RESET_NEXT))
2404 if (rr->type == type)
2406 dns_address *da = dns_address_from_rr(&dnsa, rr);
2408 DEBUG(D_host_lookup)
2409 if (!da) debug_printf("no addresses extracted from A6 RR for %s\n",
2412 /* This loop runs only once for A and AAAA records, but may run
2413 several times for an A6 record that generated multiple addresses. */
2415 for (; da; da = da->next)
2418 if (ignore_target_hosts != NULL &&
2419 verify_check_this_host(&ignore_target_hosts, NULL,
2420 host->name, da->address, NULL) == OK)
2422 DEBUG(D_host_lookup)
2423 debug_printf("ignored host %s [%s]\n", host->name, da->address);
2428 /* If this is the first address, stick it in the given host block,
2429 and change the name if the returned RR has a different name. */
2431 if (thishostlast == NULL)
2433 if (strcmpic(host->name, rr->name) != 0)
2434 host->name = string_copy_dnsdomain(rr->name);
2435 host->address = da->address;
2436 host->sort_key = host->mx * 1000 + random_number(500) + randoffset;
2437 host->status = hstatus_unknown;
2438 host->why = hwhy_unknown;
2439 thishostlast = host;
2442 /* Not the first address. Check for, and ignore, duplicates. Then
2443 insert in the chain at a random point. */
2450 /* End of our local chain is specified by "thishostlast". */
2452 for (next = host;; next = next->next)
2454 if (Ustrcmp(CS da->address, next->address) == 0) break;
2455 if (next == thishostlast) { next = NULL; break; }
2457 if (next != NULL) continue; /* With loop for next address */
2459 /* Not a duplicate */
2461 new_sort_key = host->mx * 1000 + random_number(500) + randoffset;
2462 next = store_get(sizeof(host_item));
2464 /* New address goes first: insert the new block after the first one
2465 (so as not to disturb the original pointer) but put the new address
2466 in the original block. */
2468 if (new_sort_key < host->sort_key)
2470 *next = *host; /* Copies port */
2472 host->address = da->address;
2473 host->sort_key = new_sort_key;
2474 if (thishostlast == host) thishostlast = next; /* Local last */
2475 if (*lastptr == host) *lastptr = next; /* Global last */
2478 /* Otherwise scan down the addresses for this host to find the
2479 one to insert after. */
2483 host_item *h = host;
2484 while (h != thishostlast)
2486 if (new_sort_key < h->next->sort_key) break;
2489 *next = *h; /* Copies port */
2491 next->address = da->address;
2492 next->sort_key = new_sort_key;
2493 if (h == thishostlast) thishostlast = next; /* Local last */
2494 if (h == *lastptr) *lastptr = next; /* Global last */
2502 /* Control gets here only if the second lookup (the A record) succeeded.
2503 However, the address may not be filled in if it was ignored. */
2505 return host->address
2508 ? HOST_FIND_SECURITY
2515 /*************************************************
2516 * Find IP addresses and host names via DNS *
2517 *************************************************/
2519 /* The input is a host_item structure with the name field filled in and the
2520 address field set to NULL. This may be in a chain of other host items. The
2521 lookup may result in more than one IP address, in which case we must created
2522 new host blocks for the additional addresses, and insert them into the chain.
2523 The original name may not be fully qualified. Use the fully_qualified_name
2524 argument to return the official name, as returned by the resolver.
2527 host point to initial host item
2528 ignore_target_hosts a list of hosts to ignore
2529 whichrrs flags indicating which RRs to look for:
2530 HOST_FIND_BY_SRV => look for SRV
2531 HOST_FIND_BY_MX => look for MX
2532 HOST_FIND_BY_A => look for A
2533 HOST_FIND_BY_AAAA => look for AAAA
2534 also flags indicating how the lookup is done
2535 HOST_FIND_QUALIFY_SINGLE ) passed to the
2536 HOST_FIND_SEARCH_PARENTS ) resolver
2537 HOST_FIND_IPV4_FIRST => reverse usual result ordering
2538 HOST_FIND_IPV4_ONLY => MX results elide ipv6
2539 srv_service when SRV used, the service name
2540 srv_fail_domains DNS errors for these domains => assume nonexist
2541 mx_fail_domains DNS errors for these domains => assume nonexist
2542 dnssec_d.request => make dnssec request: domainlist
2543 dnssec_d.require => ditto and nonexist failures
2544 fully_qualified_name if not NULL, return fully-qualified name
2545 removed set TRUE if local host was removed from the list
2547 Returns: HOST_FIND_FAILED Failed to find the host or domain;
2548 if there was a syntax error,
2549 host_find_failed_syntax is set.
2550 HOST_FIND_AGAIN Could not resolve at this time
2551 HOST_FIND_SECURITY dnsssec required but not acheived
2552 HOST_FOUND Host found
2553 HOST_FOUND_LOCAL The lowest MX record points to this
2554 machine, if MX records were found, or
2555 an A record that was found contains
2556 an address of the local host
2560 host_find_bydns(host_item *host, const uschar *ignore_target_hosts, int whichrrs,
2561 uschar *srv_service, uschar *srv_fail_domains, uschar *mx_fail_domains,
2562 const dnssec_domains *dnssec_d,
2563 const uschar **fully_qualified_name, BOOL *removed)
2565 host_item *h, *last;
2572 BOOL dnssec_require = dnssec_d
2573 && match_isinlist(host->name, CUSS &dnssec_d->require,
2574 0, NULL, NULL, MCL_DOMAIN, TRUE, NULL) == OK;
2575 BOOL dnssec_request = dnssec_require
2577 && match_isinlist(host->name, CUSS &dnssec_d->request,
2578 0, NULL, NULL, MCL_DOMAIN, TRUE, NULL) == OK);
2579 dnssec_status_t dnssec;
2581 /* Set the default fully qualified name to the incoming name, initialize the
2582 resolver if necessary, set up the relevant options, and initialize the flag
2583 that gets set for DNS syntax check errors. */
2585 if (fully_qualified_name != NULL) *fully_qualified_name = host->name;
2586 dns_init((whichrrs & HOST_FIND_QUALIFY_SINGLE) != 0,
2587 (whichrrs & HOST_FIND_SEARCH_PARENTS) != 0,
2589 f.host_find_failed_syntax = FALSE;
2591 /* First, if requested, look for SRV records. The service name is given; we
2592 assume TCP protocol. DNS domain names are constrained to a maximum of 256
2593 characters, so the code below should be safe. */
2595 if (whichrrs & HOST_FIND_BY_SRV)
2598 uschar * temp_fully_qualified_name;
2601 g = string_fmt_append(NULL, "_%s._tcp.%n%.256s",
2602 srv_service, &prefix_length, host->name);
2603 temp_fully_qualified_name = string_from_gstring(g);
2606 /* Search for SRV records. If the fully qualified name is different to
2607 the input name, pass back the new original domain, without the prepended
2611 lookup_dnssec_authenticated = NULL;
2612 rc = dns_lookup_timerwrap(&dnsa, temp_fully_qualified_name, ind_type,
2613 CUSS &temp_fully_qualified_name);
2616 if ((dnssec_request || dnssec_require)
2617 && !dns_is_secure(&dnsa)
2618 && dns_is_aa(&dnsa))
2619 debug_printf("DNS lookup of %.256s (SRV) requested AD, but got AA\n", host->name);
2623 if (dns_is_secure(&dnsa))
2624 { dnssec = DS_YES; lookup_dnssec_authenticated = US"yes"; }
2626 { dnssec = DS_NO; lookup_dnssec_authenticated = US"no"; }
2629 if (temp_fully_qualified_name != g->s && fully_qualified_name != NULL)
2630 *fully_qualified_name = temp_fully_qualified_name + prefix_length;
2632 /* On DNS failures, we give the "try again" error unless the domain is
2633 listed as one for which we continue. */
2635 if (rc == DNS_SUCCEED && dnssec_require && !dns_is_secure(&dnsa))
2637 log_write(L_host_lookup_failed, LOG_MAIN,
2638 "dnssec fail on SRV for %.256s", host->name);
2641 if (rc == DNS_FAIL || rc == DNS_AGAIN)
2644 if (match_isinlist(host->name, CUSS &srv_fail_domains, 0, NULL, NULL,
2645 MCL_DOMAIN, TRUE, NULL) != OK)
2647 { yield = HOST_FIND_AGAIN; goto out; }
2648 DEBUG(D_host_lookup) debug_printf("DNS_%s treated as DNS_NODATA "
2649 "(domain in srv_fail_domains)\n", (rc == DNS_FAIL)? "FAIL":"AGAIN");
2653 /* If we did not find any SRV records, search the DNS for MX records, if
2654 requested to do so. If the result is DNS_NOMATCH, it means there is no such
2655 domain, and there's no point in going on to look for address records with the
2656 same domain. The result will be DNS_NODATA if the domain exists but has no MX
2657 records. On DNS failures, we give the "try again" error unless the domain is
2658 listed as one for which we continue. */
2660 if (rc != DNS_SUCCEED && whichrrs & HOST_FIND_BY_MX)
2664 lookup_dnssec_authenticated = NULL;
2665 rc = dns_lookup_timerwrap(&dnsa, host->name, ind_type, fully_qualified_name);
2668 if ( (dnssec_request || dnssec_require)
2669 && !dns_is_secure(&dnsa)
2670 && dns_is_aa(&dnsa))
2671 debug_printf("DNS lookup of %.256s (MX) requested AD, but got AA\n", host->name);
2674 if (dns_is_secure(&dnsa))
2676 DEBUG(D_host_lookup) debug_printf("%s MX DNSSEC\n", host->name);
2677 dnssec = DS_YES; lookup_dnssec_authenticated = US"yes";
2681 dnssec = DS_NO; lookup_dnssec_authenticated = US"no";
2687 yield = HOST_FIND_FAILED; goto out;
2690 if (!dnssec_require || dns_is_secure(&dnsa))
2692 DEBUG(D_host_lookup)
2693 debug_printf("dnssec fail on MX for %.256s", host->name);
2695 if (match_isinlist(host->name, CUSS &mx_fail_domains, 0, NULL, NULL,
2696 MCL_DOMAIN, TRUE, NULL) != OK)
2697 { yield = HOST_FIND_SECURITY; goto out; }
2705 if (match_isinlist(host->name, CUSS &mx_fail_domains, 0, NULL, NULL,
2706 MCL_DOMAIN, TRUE, NULL) != OK)
2708 { yield = HOST_FIND_AGAIN; goto out; }
2709 DEBUG(D_host_lookup) debug_printf("DNS_%s treated as DNS_NODATA "
2710 "(domain in mx_fail_domains)\n", (rc == DNS_FAIL)? "FAIL":"AGAIN");
2715 /* If we haven't found anything yet, and we are requested to do so, try for an
2716 A or AAAA record. If we find it (or them) check to see that it isn't the local
2719 if (rc != DNS_SUCCEED)
2721 if (!(whichrrs & (HOST_FIND_BY_A | HOST_FIND_BY_AAAA)))
2723 DEBUG(D_host_lookup) debug_printf("Address records are not being sought\n");
2724 yield = HOST_FIND_FAILED;
2728 last = host; /* End of local chainlet */
2730 host->port = PORT_NONE;
2731 host->dnssec = DS_UNK;
2732 lookup_dnssec_authenticated = NULL;
2733 rc = set_address_from_dns(host, &last, ignore_target_hosts, FALSE,
2734 fully_qualified_name, dnssec_request, dnssec_require, whichrrs);
2736 /* If one or more address records have been found, check that none of them
2737 are local. Since we know the host items all have their IP addresses
2738 inserted, host_scan_for_local_hosts() can only return HOST_FOUND or
2739 HOST_FOUND_LOCAL. We do not need to scan for duplicate IP addresses here,
2740 because set_address_from_dns() removes them. */
2742 if (rc == HOST_FOUND)
2743 rc = host_scan_for_local_hosts(host, &last, removed);
2745 if (rc == HOST_IGNORED) rc = HOST_FIND_FAILED; /* No special action */
2747 DEBUG(D_host_lookup)
2750 if (host->address != NULL)
2752 if (fully_qualified_name != NULL)
2753 debug_printf("fully qualified name = %s\n", *fully_qualified_name);
2754 for (h = host; h != last->next; h = h->next)
2755 debug_printf("%s %s mx=%d sort=%d %s\n", h->name,
2756 (h->address == NULL)? US"<null>" : h->address, h->mx, h->sort_key,
2757 (h->status >= hstatus_unusable)? US"*" : US"");
2765 /* We have found one or more MX or SRV records. Sort them according to
2766 precedence. Put the data for the first one into the existing host block, and
2767 insert new host_item blocks into the chain for the remainder. For equal
2768 precedences one is supposed to randomize the order. To make this happen, the
2769 sorting is actually done on the MX value * 1000 + a random number. This is put
2770 into a host field called sort_key.
2772 In the case of hosts with both IPv6 and IPv4 addresses, we want to choose the
2773 IPv6 address in preference. At this stage, we don't know what kind of address
2774 the host has. We choose a random number < 500; if later we find an A record
2775 first, we add 500 to the random number. Then for any other address records, we
2776 use random numbers in the range 0-499 for AAAA records and 500-999 for A
2779 At this point we remove any duplicates that point to the same host, retaining
2780 only the one with the lowest precedence. We cannot yet check for precedence
2781 greater than that of the local host, because that test cannot be properly done
2782 until the addresses have been found - an MX record may point to a name for this
2783 host which is not the primary hostname. */
2785 last = NULL; /* Indicates that not even the first item is filled yet */
2787 for (rr = dns_next_rr(&dnsa, &dnss, RESET_ANSWERS);
2789 rr = dns_next_rr(&dnsa, &dnss, RESET_NEXT)) if (rr->type == ind_type)
2791 int precedence, weight;
2792 int port = PORT_NONE;
2793 const uschar * s = rr->data; /* MUST be unsigned for GETSHORT */
2796 GETSHORT(precedence, s); /* Pointer s is advanced */
2798 /* For MX records, we use a random "weight" which causes multiple records of
2799 the same precedence to sort randomly. */
2801 if (ind_type == T_MX)
2802 weight = random_number(500);
2805 /* SRV records are specified with a port and a weight. The weight is used
2806 in a special algorithm. However, to start with, we just use it to order the
2807 records of equal priority (precedence). */
2808 GETSHORT(weight, s);
2812 /* Get the name of the host pointed to. */
2814 (void)dn_expand(dnsa.answer, dnsa.answer + dnsa.answerlen, s,
2815 (DN_EXPAND_ARG4_TYPE)data, sizeof(data));
2817 /* Check that we haven't already got this host on the chain; if we have,
2818 keep only the lower precedence. This situation shouldn't occur, but you
2819 never know what junk might get into the DNS (and this case has been seen on
2820 more than one occasion). */
2822 if (last) /* This is not the first record */
2824 host_item *prev = NULL;
2826 for (h = host; h != last->next; prev = h, h = h->next)
2827 if (strcmpic(h->name, data) == 0)
2829 DEBUG(D_host_lookup)
2830 debug_printf("discarded duplicate host %s (MX=%d)\n", data,
2831 precedence > h->mx ? precedence : h->mx);
2832 if (precedence >= h->mx) goto NEXT_MX_RR; /* Skip greater precedence */
2833 if (h == host) /* Override first item */
2836 host->sort_key = precedence * 1000 + weight;
2840 /* Unwanted host item is not the first in the chain, so we can get
2841 get rid of it by cutting it out. */
2843 prev->next = h->next;
2844 if (h == last) last = prev;
2849 /* If this is the first MX or SRV record, put the data into the existing host
2850 block. Otherwise, add a new block in the correct place; if it has to be
2851 before the first block, copy the first block's data to a new second block. */
2855 host->name = string_copy_dnsdomain(data);
2856 host->address = NULL;
2858 host->mx = precedence;
2859 host->sort_key = precedence * 1000 + weight;
2860 host->status = hstatus_unknown;
2861 host->why = hwhy_unknown;
2862 host->dnssec = dnssec;
2867 /* Make a new host item and seek the correct insertion place */
2869 int sort_key = precedence * 1000 + weight;
2870 host_item *next = store_get(sizeof(host_item));
2871 next->name = string_copy_dnsdomain(data);
2872 next->address = NULL;
2874 next->mx = precedence;
2875 next->sort_key = sort_key;
2876 next->status = hstatus_unknown;
2877 next->why = hwhy_unknown;
2878 next->dnssec = dnssec;
2881 /* Handle the case when we have to insert before the first item. */
2883 if (sort_key < host->sort_key)
2890 if (last == host) last = next;
2894 /* Else scan down the items we have inserted as part of this exercise;
2895 don't go further. */
2897 for (h = host; h != last; h = h->next)
2898 if (sort_key < h->next->sort_key)
2900 next->next = h->next;
2905 /* Join on after the last host item that's part of this
2906 processing if we haven't stopped sooner. */
2910 next->next = last->next;
2917 NEXT_MX_RR: continue;
2920 if (!last) /* No rr of correct type; give up */
2922 yield = HOST_FIND_FAILED;
2926 /* If the list of hosts was obtained from SRV records, there are two things to
2927 do. First, if there is only one host, and it's name is ".", it means there is
2928 no SMTP service at this domain. Otherwise, we have to sort the hosts of equal
2929 priority according to their weights, using an algorithm that is defined in RFC
2930 2782. The hosts are currently sorted by priority and weight. For each priority
2931 group we have to pick off one host and put it first, and then repeat for any
2932 remaining in the same priority group. */
2934 if (ind_type == T_SRV)
2938 if (host == last && host->name[0] == 0)
2940 DEBUG(D_host_lookup) debug_printf("the single SRV record is \".\"\n");
2941 yield = HOST_FIND_FAILED;
2945 DEBUG(D_host_lookup)
2947 debug_printf("original ordering of hosts from SRV records:\n");
2948 for (h = host; h != last->next; h = h->next)
2949 debug_printf(" %s P=%d W=%d\n", h->name, h->mx, h->sort_key % 1000);
2952 for (pptr = &host, h = host; h != last; pptr = &h->next, h = h->next)
2957 /* Find the last following host that has the same precedence. At the same
2958 time, compute the sum of the weights and the running totals. These can be
2959 stored in the sort_key field. */
2961 for (hh = h; hh != last; hh = hh->next)
2963 int weight = hh->sort_key % 1000; /* was precedence * 1000 + weight */
2966 if (hh->mx != hh->next->mx) break;
2969 /* If there's more than one host at this precedence (priority), we need to
2970 pick one to go first. */
2976 int randomizer = random_number(sum + 1);
2978 for (ppptr = pptr, hhh = h;
2980 ppptr = &hhh->next, hhh = hhh->next)
2981 if (hhh->sort_key >= randomizer)
2984 /* hhh now points to the host that should go first; ppptr points to the
2985 place that points to it. Unfortunately, if the start of the minilist is
2986 the start of the entire list, we can't just swap the items over, because
2987 we must not change the value of host, since it is passed in from outside.
2988 One day, this could perhaps be changed.
2990 The special case is fudged by putting the new item *second* in the chain,
2991 and then transferring the data between the first and second items. We
2992 can't just swap the first and the chosen item, because that would mean
2993 that an item with zero weight might no longer be first. */
2997 *ppptr = hhh->next; /* Cuts it out of the chain */
3001 host_item temp = *h;
3004 hhh->next = temp.next;
3009 hhh->next = h; /* The rest of the chain follows it */
3010 *pptr = hhh; /* It takes the place of h */
3011 h = hhh; /* It's now the start of this minilist */
3016 /* A host has been chosen to be first at this priority and h now points
3017 to this host. There may be others at the same priority, or others at a
3018 different priority. Before we leave this host, we need to put back a sort
3019 key of the traditional MX kind, in case this host is multihomed, because
3020 the sort key is used for ordering the multiple IP addresses. We do not need
3021 to ensure that these new sort keys actually reflect the order of the hosts,
3024 h->sort_key = h->mx * 1000 + random_number(500);
3025 } /* Move on to the next host */
3028 /* Now we have to find IP addresses for all the hosts. We have ensured above
3029 that the names in all the host items are unique. Before release 4.61 we used to
3030 process records from the additional section in the DNS packet that returned the
3031 MX or SRV records. However, a DNS name server is free to drop any resource
3032 records from the additional section. In theory, this has always been a
3033 potential problem, but it is exacerbated by the advent of IPv6. If a host had
3034 several IPv4 addresses and some were not in the additional section, at least
3035 Exim would try the others. However, if a host had both IPv4 and IPv6 addresses
3036 and all the IPv4 (say) addresses were absent, Exim would try only for a IPv6
3037 connection, and never try an IPv4 address. When there was only IPv4
3038 connectivity, this was a disaster that did in practice occur.
3040 So, from release 4.61 onwards, we always search for A and AAAA records
3041 explicitly. The names shouldn't point to CNAMES, but we use the general lookup
3042 function that handles them, just in case. If any lookup gives a soft error,
3043 change the default yield.
3045 For these DNS lookups, we must disable qualify_single and search_parents;
3046 otherwise invalid host names obtained from MX or SRV records can cause trouble
3047 if they happen to match something local. */
3049 yield = HOST_FIND_FAILED; /* Default yield */
3050 dns_init(FALSE, FALSE, /* Disable qualify_single and search_parents */
3051 dnssec_request || dnssec_require);
3053 for (h = host; h != last->next; h = h->next)
3055 if (h->address) continue; /* Inserted by a multihomed host */
3057 rc = set_address_from_dns(h, &last, ignore_target_hosts, allow_mx_to_ip,
3058 NULL, dnssec_request, dnssec_require,
3059 whichrrs & HOST_FIND_IPV4_ONLY
3060 ? HOST_FIND_BY_A : HOST_FIND_BY_A | HOST_FIND_BY_AAAA);
3061 if (rc != HOST_FOUND)
3063 h->status = hstatus_unusable;
3066 case HOST_FIND_AGAIN: yield = rc; h->why = hwhy_deferred; break;
3067 case HOST_FIND_SECURITY: yield = rc; h->why = hwhy_insecure; break;
3068 case HOST_IGNORED: h->why = hwhy_ignored; break;
3069 default: h->why = hwhy_failed; break;
3074 /* Scan the list for any hosts that are marked unusable because they have
3075 been explicitly ignored, and remove them from the list, as if they did not
3076 exist. If we end up with just a single, ignored host, flatten its fields as if
3077 nothing was found. */
3079 if (ignore_target_hosts)
3081 host_item *prev = NULL;
3082 for (h = host; h != last->next; h = h->next)
3085 if (h->why != hwhy_ignored) /* Non ignored host, just continue */
3087 else if (prev == NULL) /* First host is ignored */
3089 if (h != last) /* First is not last */
3091 if (h->next == last) last = h; /* Overwrite it with next */
3092 *h = *(h->next); /* and reprocess it. */
3093 goto REDO; /* C should have redo, like Perl */
3096 else /* Ignored host is not first - */
3098 prev->next = h->next;
3099 if (h == last) last = prev;
3103 if (host->why == hwhy_ignored) host->address = NULL;
3106 /* There is still one complication in the case of IPv6. Although the code above
3107 arranges that IPv6 addresses take precedence over IPv4 addresses for multihomed
3108 hosts, it doesn't do this for addresses that apply to different hosts with the
3109 same MX precedence, because the sorting on MX precedence happens first. So we
3110 have to make another pass to check for this case. We ensure that, within a
3111 single MX preference value, IPv6 addresses come first. This can separate the
3112 addresses of a multihomed host, but that should not matter. */
3115 if (h != last && !disable_ipv6) for (h = host; h != last; h = h->next)
3118 host_item *next = h->next;
3120 if ( h->mx != next->mx /* If next is different MX */
3121 || !h->address /* OR this one is unset */
3123 continue; /* move on to next */
3125 if ( whichrrs & HOST_FIND_IPV4_FIRST
3126 ? !Ustrchr(h->address, ':') /* OR this one is IPv4 */
3128 && Ustrchr(next->address, ':') /* OR next is IPv6 */
3130 : Ustrchr(h->address, ':') /* OR this one is IPv6 */
3132 && !Ustrchr(next->address, ':') /* OR next is IPv4 */
3134 continue; /* move on to next */
3136 temp = *h; /* otherwise, swap */
3137 temp.next = next->next;
3144 /* Remove any duplicate IP addresses and then scan the list of hosts for any
3145 whose IP addresses are on the local host. If any are found, all hosts with the
3146 same or higher MX values are removed. However, if the local host has the lowest
3147 numbered MX, then HOST_FOUND_LOCAL is returned. Otherwise, if at least one host
3148 with an IP address is on the list, HOST_FOUND is returned. Otherwise,
3149 HOST_FIND_FAILED is returned, but in this case do not update the yield, as it
3150 might have been set to HOST_FIND_AGAIN just above here. If not, it will already
3151 be HOST_FIND_FAILED. */
3153 host_remove_duplicates(host, &last);
3154 rc = host_scan_for_local_hosts(host, &last, removed);
3155 if (rc != HOST_FIND_FAILED) yield = rc;
3157 DEBUG(D_host_lookup)
3159 if (fully_qualified_name != NULL)
3160 debug_printf("fully qualified name = %s\n", *fully_qualified_name);
3161 debug_printf("host_find_bydns yield = %s (%d); returned hosts:\n",
3162 (yield == HOST_FOUND)? "HOST_FOUND" :
3163 (yield == HOST_FOUND_LOCAL)? "HOST_FOUND_LOCAL" :
3164 (yield == HOST_FIND_SECURITY)? "HOST_FIND_SECURITY" :
3165 (yield == HOST_FIND_AGAIN)? "HOST_FIND_AGAIN" :
3166 (yield == HOST_FIND_FAILED)? "HOST_FIND_FAILED" : "?",
3168 for (h = host; h != last->next; h = h->next)
3170 debug_printf(" %s %s MX=%d %s", h->name,
3171 !h->address ? US"<null>" : h->address, h->mx,
3172 h->dnssec == DS_YES ? US"DNSSEC " : US"");
3173 if (h->port != PORT_NONE) debug_printf("port=%d ", h->port);
3174 if (h->status >= hstatus_unusable) debug_printf("*");
3181 dns_init(FALSE, FALSE, FALSE); /* clear the dnssec bit for getaddrbyname */
3185 /*************************************************
3186 **************************************************
3187 * Stand-alone test program *
3188 **************************************************
3189 *************************************************/
3193 int main(int argc, char **cargv)
3196 int whichrrs = HOST_FIND_BY_MX | HOST_FIND_BY_A | HOST_FIND_BY_AAAA;
3197 BOOL byname = FALSE;
3198 BOOL qualify_single = TRUE;
3199 BOOL search_parents = FALSE;
3200 BOOL request_dnssec = FALSE;
3201 BOOL require_dnssec = FALSE;
3202 uschar **argv = USS cargv;
3205 disable_ipv6 = FALSE;
3206 primary_hostname = US"";
3207 store_pool = POOL_MAIN;
3208 debug_selector = D_host_lookup|D_interface;
3209 debug_file = stdout;
3210 debug_fd = fileno(debug_file);
3212 printf("Exim stand-alone host functions test\n");
3214 host_find_interfaces();
3215 debug_selector = D_host_lookup | D_dns;
3217 if (argc > 1) primary_hostname = argv[1];
3219 /* So that debug level changes can be done first */
3221 dns_init(qualify_single, search_parents, FALSE);
3223 printf("Testing host lookup\n");
3225 while (Ufgets(buffer, 256, stdin) != NULL)
3228 int len = Ustrlen(buffer);
3229 uschar *fully_qualified_name;
3231 while (len > 0 && isspace(buffer[len-1])) len--;
3234 if (Ustrcmp(buffer, "q") == 0) break;
3236 if (Ustrcmp(buffer, "byname") == 0) byname = TRUE;
3237 else if (Ustrcmp(buffer, "no_byname") == 0) byname = FALSE;
3238 else if (Ustrcmp(buffer, "a_only") == 0) whichrrs = HOST_FIND_BY_A | HOST_FIND_BY_AAAA;
3239 else if (Ustrcmp(buffer, "mx_only") == 0) whichrrs = HOST_FIND_BY_MX;
3240 else if (Ustrcmp(buffer, "srv_only") == 0) whichrrs = HOST_FIND_BY_SRV;
3241 else if (Ustrcmp(buffer, "srv+a") == 0)
3242 whichrrs = HOST_FIND_BY_SRV | HOST_FIND_BY_A | HOST_FIND_BY_AAAA;
3243 else if (Ustrcmp(buffer, "srv+mx") == 0)
3244 whichrrs = HOST_FIND_BY_SRV | HOST_FIND_BY_MX;
3245 else if (Ustrcmp(buffer, "srv+mx+a") == 0)
3246 whichrrs = HOST_FIND_BY_SRV | HOST_FIND_BY_MX | HOST_FIND_BY_A | HOST_FIND_BY_AAAA;
3247 else if (Ustrcmp(buffer, "qualify_single") == 0) qualify_single = TRUE;
3248 else if (Ustrcmp(buffer, "no_qualify_single") == 0) qualify_single = FALSE;
3249 else if (Ustrcmp(buffer, "search_parents") == 0) search_parents = TRUE;
3250 else if (Ustrcmp(buffer, "no_search_parents") == 0) search_parents = FALSE;
3251 else if (Ustrcmp(buffer, "request_dnssec") == 0) request_dnssec = TRUE;
3252 else if (Ustrcmp(buffer, "no_request_dnssec") == 0) request_dnssec = FALSE;
3253 else if (Ustrcmp(buffer, "require_dnssec") == 0) require_dnssec = TRUE;
3254 else if (Ustrcmp(buffer, "no_require_dnssec") == 0) require_dnssec = FALSE;
3255 else if (Ustrcmp(buffer, "test_harness") == 0)
3256 f.running_in_test_harness = !f.running_in_test_harness;
3257 else if (Ustrcmp(buffer, "ipv6") == 0) disable_ipv6 = !disable_ipv6;
3258 else if (Ustrcmp(buffer, "res_debug") == 0)
3260 _res.options ^= RES_DEBUG;
3262 else if (Ustrncmp(buffer, "retrans", 7) == 0)
3264 (void)sscanf(CS(buffer+8), "%d", &dns_retrans);
3265 _res.retrans = dns_retrans;
3267 else if (Ustrncmp(buffer, "retry", 5) == 0)
3269 (void)sscanf(CS(buffer+6), "%d", &dns_retry);
3270 _res.retry = dns_retry;
3274 int flags = whichrrs;
3281 h.status = hstatus_unknown;
3282 h.why = hwhy_unknown;
3285 if (qualify_single) flags |= HOST_FIND_QUALIFY_SINGLE;
3286 if (search_parents) flags |= HOST_FIND_SEARCH_PARENTS;
3288 d.request = request_dnssec ? &h.name : NULL;
3289 d.require = require_dnssec ? &h.name : NULL;
3292 ? host_find_byname(&h, NULL, flags, &fully_qualified_name, TRUE)
3293 : host_find_bydns(&h, NULL, flags, US"smtp", NULL, NULL,
3294 &d, &fully_qualified_name, NULL);
3298 case HOST_FIND_FAILED: printf("Failed\n"); break;
3299 case HOST_FIND_AGAIN: printf("Again\n"); break;
3300 case HOST_FIND_SECURITY: printf("Security\n"); break;
3301 case HOST_FOUND_LOCAL: printf("Local\n"); break;
3308 printf("Testing host_aton\n");
3310 while (Ufgets(buffer, 256, stdin) != NULL)
3314 int len = Ustrlen(buffer);
3316 while (len > 0 && isspace(buffer[len-1])) len--;
3319 if (Ustrcmp(buffer, "q") == 0) break;
3321 len = host_aton(buffer, x);
3322 printf("length = %d ", len);
3323 for (i = 0; i < len; i++)
3325 printf("%04x ", (x[i] >> 16) & 0xffff);
3326 printf("%04x ", x[i] & 0xffff);
3333 printf("Testing host_name_lookup\n");
3335 while (Ufgets(buffer, 256, stdin) != NULL)
3337 int len = Ustrlen(buffer);
3338 while (len > 0 && isspace(buffer[len-1])) len--;
3340 if (Ustrcmp(buffer, "q") == 0) break;
3341 sender_host_address = buffer;
3342 sender_host_name = NULL;
3343 sender_host_aliases = NULL;
3344 host_lookup_msg = US"";
3345 host_lookup_failed = FALSE;
3346 if (host_name_lookup() == FAIL) /* Debug causes printing */
3347 printf("Lookup failed:%s\n", host_lookup_msg);
3355 #endif /* STAND_ALONE */