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;
184 debug_printf("using host_fake_gethostbyname for %s (%s)\n", name,
185 (af == AF_INET)? "IPv4" : "IPv6");
187 /* Handle unqualified "localhost" */
189 if (Ustrcmp(name, "localhost") == 0)
190 lname = (af == AF_INET)? US"127.0.0.1" : US"::1";
192 /* Handle a literal IP address */
194 if ((ipa = string_is_ip_address(lname, NULL)) != 0)
196 if ((ipa == 4 && af == AF_INET) ||
197 (ipa == 6 && af == AF_INET6))
200 yield = store_get(sizeof(struct hostent));
201 alist = store_get(2 * sizeof(char *));
202 adds = store_get(alen);
203 yield->h_name = CS name;
204 yield->h_aliases = NULL;
205 yield->h_addrtype = af;
206 yield->h_length = alen;
207 yield->h_addr_list = CSS alist;
209 for (int n = host_aton(lname, x), i = 0; i < n; i++)
212 *adds++ = (y >> 24) & 255;
213 *adds++ = (y >> 16) & 255;
214 *adds++ = (y >> 8) & 255;
220 /* Wrong kind of literal address */
224 *error_num = HOST_NOT_FOUND;
229 /* Handle a host name */
233 int type = (af == AF_INET)? T_A:T_AAAA;
234 int rc = dns_lookup_timerwrap(&dnsa, lname, type, NULL);
237 lookup_dnssec_authenticated = NULL;
241 case DNS_SUCCEED: break;
242 case DNS_NOMATCH: *error_num = HOST_NOT_FOUND; return NULL;
243 case DNS_NODATA: *error_num = NO_DATA; return NULL;
244 case DNS_AGAIN: *error_num = TRY_AGAIN; return NULL;
246 case DNS_FAIL: *error_num = NO_RECOVERY; return NULL;
249 for (dns_record * rr = dns_next_rr(&dnsa, &dnss, RESET_ANSWERS);
251 rr = dns_next_rr(&dnsa, &dnss, RESET_NEXT)) if (rr->type == type)
254 yield = store_get(sizeof(struct hostent));
255 alist = store_get((count + 1) * sizeof(char *));
256 adds = store_get(count *alen);
258 yield->h_name = CS name;
259 yield->h_aliases = NULL;
260 yield->h_addrtype = af;
261 yield->h_length = alen;
262 yield->h_addr_list = CSS alist;
264 for (dns_record * rr = dns_next_rr(&dnsa, &dnss, RESET_ANSWERS);
266 rr = dns_next_rr(&dnsa, &dnss, RESET_NEXT)) if (rr->type == type)
270 if (!(da = dns_address_from_rr(&dnsa, rr))) break;
272 for (int n = host_aton(da->address, x), i = 0; i < n; i++)
275 *adds++ = (y >> 24) & 255;
276 *adds++ = (y >> 16) & 255;
277 *adds++ = (y >> 8) & 255;
289 /*************************************************
290 * Build chain of host items from list *
291 *************************************************/
293 /* This function builds a chain of host items from a textual list of host
294 names. It does not do any lookups. If randomize is true, the chain is build in
295 a randomized order. There may be multiple groups of independently randomized
296 hosts; they are delimited by a host name consisting of just "+".
299 anchor anchor for the chain
301 randomize TRUE for randomizing
307 host_build_hostlist(host_item **anchor, const uschar *list, BOOL randomize)
310 int fake_mx = MX_NONE; /* This value is actually -1 */
314 if (randomize) fake_mx--; /* Start at -2 for randomizing */
318 while ((name = string_nextinlist(&list, &sep, NULL, 0)))
322 if (name[0] == '+' && name[1] == 0) /* "+" delimits a randomized group */
323 { /* ignore if not randomizing */
324 if (randomize) fake_mx--;
328 h = store_get(sizeof(host_item));
333 h->sort_key = randomize? (-fake_mx)*1000 + random_number(1000) : 0;
334 h->status = hstatus_unknown;
335 h->why = hwhy_unknown;
345 host_item *hh = *anchor;
346 if (h->sort_key < hh->sort_key)
353 while (hh->next && h->sort_key >= hh->next->sort_key)
366 /*************************************************
367 * Extract port from address string *
368 *************************************************/
370 /* In the spool file, and in the -oMa and -oMi options, a host plus port is
371 given as an IP address followed by a dot and a port number. This function
374 An alternative format for the -oMa and -oMi options is [ip address]:port which
375 is what Exim 4 uses for output, because it seems to becoming commonly used,
376 whereas the dot form confuses some programs/people. So we recognize that form
380 address points to the string; if there is a port, the '.' in the string
381 is overwritten with zero to terminate the address; if the string
382 is in the [xxx]:ppp format, the address is shifted left and the
385 Returns: 0 if there is no port, else the port number. If there's a syntax
386 error, leave the incoming address alone, and return 0.
390 host_address_extract_port(uschar *address)
395 /* Handle the "bracketed with colon on the end" format */
399 uschar *rb = address + 1;
400 while (*rb != 0 && *rb != ']') rb++;
401 if (*rb++ == 0) return 0; /* Missing ]; leave invalid address */
404 port = Ustrtol(rb + 1, &endptr, 10);
405 if (*endptr != 0) return 0; /* Invalid port; leave invalid address */
407 else if (*rb != 0) return 0; /* Bad syntax; leave invalid address */
408 memmove(address, address + 1, rb - address - 2);
412 /* Handle the "dot on the end" format */
416 int skip = -3; /* Skip 3 dots in IPv4 addresses */
418 while (*(++address) != 0)
421 if (ch == ':') skip = 0; /* Skip 0 dots in IPv6 addresses */
422 else if (ch == '.' && skip++ >= 0) break;
424 if (*address == 0) return 0;
425 port = Ustrtol(address + 1, &endptr, 10);
426 if (*endptr != 0) return 0; /* Invalid port; leave invalid address */
434 /*************************************************
435 * Get port from a host item's name *
436 *************************************************/
438 /* This function is called when finding the IP address for a host that is in a
439 list of hosts explicitly configured, such as in the manualroute router, or in a
440 fallback hosts list. We see if there is a port specification at the end of the
441 host name, and if so, remove it. A minimum length of 3 is required for the
442 original name; nothing shorter is recognized as having a port.
444 We test for a name ending with a sequence of digits; if preceded by colon we
445 have a port if the character before the colon is ] and the name starts with [
446 or if there are no other colons in the name (i.e. it's not an IPv6 address).
448 Arguments: pointer to the host item
449 Returns: a port number or PORT_NONE
453 host_item_get_port(host_item *h)
457 int len = Ustrlen(h->name);
459 if (len < 3 || (p = h->name + len - 1, !isdigit(*p))) return PORT_NONE;
461 /* Extract potential port number */
466 while (p > h->name + 1 && isdigit(*p))
468 port += (*p-- - '0') * x;
472 /* The smallest value of p at this point is h->name + 1. */
474 if (*p != ':') return PORT_NONE;
476 if (p[-1] == ']' && h->name[0] == '[')
477 h->name = string_copyn(h->name + 1, p - h->name - 2);
478 else if (Ustrchr(h->name, ':') == p)
479 h->name = string_copyn(h->name, p - h->name);
480 else return PORT_NONE;
482 DEBUG(D_route|D_host_lookup) debug_printf("host=%s port=%d\n", h->name, port);
488 #ifndef STAND_ALONE /* Omit when standalone testing */
490 /*************************************************
491 * Build sender_fullhost and sender_rcvhost *
492 *************************************************/
494 /* This function is called when sender_host_name and/or sender_helo_name
495 have been set. Or might have been set - for a local message read off the spool
496 they won't be. In that case, do nothing. Otherwise, set up the fullhost string
499 (a) No sender_host_name or sender_helo_name: "[ip address]"
500 (b) Just sender_host_name: "host_name [ip address]"
501 (c) Just sender_helo_name: "(helo_name) [ip address]" unless helo is IP
502 in which case: "[ip address}"
503 (d) The two are identical: "host_name [ip address]" includes helo = IP
504 (e) The two are different: "host_name (helo_name) [ip address]"
506 If log_incoming_port is set, the sending host's port number is added to the IP
509 This function also builds sender_rcvhost for use in Received: lines, whose
510 syntax is a bit different. This value also includes the RFC 1413 identity.
511 There wouldn't be two different variables if I had got all this right in the
514 Because this data may survive over more than one incoming SMTP message, it has
515 to be in permanent store. However, STARTTLS has to be forgotten and redone
516 on a multi-message conn, so this will be called once per message then. Hence
517 we use malloc, so we can free.
524 host_build_sender_fullhost(void)
526 BOOL show_helo = TRUE;
527 uschar * address, * fullhost, * rcvhost, * reset_point;
530 if (!sender_host_address) return;
532 reset_point = store_get(0);
534 /* Set up address, with or without the port. After discussion, it seems that
535 the only format that doesn't cause trouble is [aaaa]:pppp. However, we can't
536 use this directly as the first item for Received: because it ain't an RFC 2822
539 address = string_sprintf("[%s]:%d", sender_host_address, sender_host_port);
540 if (!LOGGING(incoming_port) || sender_host_port <= 0)
541 *(Ustrrchr(address, ':')) = 0;
543 /* If there's no EHLO/HELO data, we can't show it. */
545 if (!sender_helo_name) show_helo = FALSE;
547 /* If HELO/EHLO was followed by an IP literal, it's messy because of two
548 features of IPv6. Firstly, there's the "IPv6:" prefix (Exim is liberal and
549 doesn't require this, for historical reasons). Secondly, IPv6 addresses may not
550 be given in canonical form, so we have to canonicalize them before comparing. As
551 it happens, the code works for both IPv4 and IPv6. */
553 else if (sender_helo_name[0] == '[' &&
554 sender_helo_name[(len=Ustrlen(sender_helo_name))-1] == ']')
559 if (strncmpic(sender_helo_name + 1, US"IPv6:", 5) == 0) offset += 5;
560 if (strncmpic(sender_helo_name + 1, US"IPv4:", 5) == 0) offset += 5;
562 helo_ip = string_copyn(sender_helo_name + offset, len - offset - 1);
564 if (string_is_ip_address(helo_ip, NULL) != 0)
568 uschar ipx[48], ipy[48]; /* large enough for full IPv6 */
570 sizex = host_aton(helo_ip, x);
571 sizey = host_aton(sender_host_address, y);
573 (void)host_nmtoa(sizex, x, -1, ipx, ':');
574 (void)host_nmtoa(sizey, y, -1, ipy, ':');
576 if (strcmpic(ipx, ipy) == 0) show_helo = FALSE;
580 /* Host name is not verified */
582 if (!sender_host_name)
584 uschar *portptr = Ustrstr(address, "]:");
586 int adlen; /* Sun compiler doesn't like ++ in initializers */
588 adlen = portptr ? (++portptr - address) : Ustrlen(address);
589 fullhost = sender_helo_name
590 ? string_sprintf("(%s) %s", sender_helo_name, address)
593 g = string_catn(NULL, address, adlen);
595 if (sender_ident || show_helo || portptr)
598 g = string_catn(g, US" (", 2);
602 g = string_append(g, 2, US"port=", portptr + 1);
605 g = string_append(g, 2,
606 firstptr == g->ptr ? US"helo=" : US" helo=", sender_helo_name);
609 g = string_append(g, 2,
610 firstptr == g->ptr ? US"ident=" : US" ident=", sender_ident);
612 g = string_catn(g, US")", 1);
615 rcvhost = string_from_gstring(g);
618 /* Host name is known and verified. Unless we've already found that the HELO
619 data matches the IP address, compare it with the name. */
623 if (show_helo && strcmpic(sender_host_name, sender_helo_name) == 0)
628 fullhost = string_sprintf("%s (%s) %s", sender_host_name,
629 sender_helo_name, address);
630 rcvhost = sender_ident
631 ? string_sprintf("%s\n\t(%s helo=%s ident=%s)", sender_host_name,
632 address, sender_helo_name, sender_ident)
633 : string_sprintf("%s (%s helo=%s)", sender_host_name,
634 address, sender_helo_name);
638 fullhost = string_sprintf("%s %s", sender_host_name, address);
639 rcvhost = sender_ident
640 ? string_sprintf("%s (%s ident=%s)", sender_host_name, address,
642 : string_sprintf("%s (%s)", sender_host_name, address);
646 if (sender_fullhost) store_free(sender_fullhost);
647 sender_fullhost = string_copy_malloc(fullhost);
648 if (sender_rcvhost) store_free(sender_rcvhost);
649 sender_rcvhost = string_copy_malloc(rcvhost);
651 store_reset(reset_point);
653 DEBUG(D_host_lookup) debug_printf("sender_fullhost = %s\n", sender_fullhost);
654 DEBUG(D_host_lookup) debug_printf("sender_rcvhost = %s\n", sender_rcvhost);
659 /*************************************************
660 * Build host+ident message *
661 *************************************************/
663 /* Used when logging rejections and various ACL and SMTP incidents. The text
664 return depends on whether sender_fullhost and sender_ident are set or not:
666 no ident, no host => U=unknown
667 no ident, host set => H=sender_fullhost
668 ident set, no host => U=ident
669 ident set, host set => H=sender_fullhost U=ident
672 useflag TRUE if first item to be flagged (H= or U=); if there are two
673 items, the second is always flagged
675 Returns: pointer to a string in big_buffer
679 host_and_ident(BOOL useflag)
681 if (!sender_fullhost)
682 (void)string_format(big_buffer, big_buffer_size, "%s%s", useflag ? "U=" : "",
683 sender_ident ? sender_ident : US"unknown");
686 uschar * flag = useflag ? US"H=" : US"";
687 uschar * iface = US"";
688 if (LOGGING(incoming_interface) && interface_address)
689 iface = string_sprintf(" I=[%s]:%d", interface_address, interface_port);
691 (void)string_format(big_buffer, big_buffer_size, "%s%s%s U=%s",
692 flag, sender_fullhost, iface, sender_ident);
694 (void)string_format(big_buffer, big_buffer_size, "%s%s%s",
695 flag, sender_fullhost, iface);
700 #endif /* STAND_ALONE */
705 /*************************************************
706 * Build list of local interfaces *
707 *************************************************/
709 /* This function interprets the contents of the local_interfaces or
710 extra_local_interfaces options, and creates an ip_address_item block for each
711 item on the list. There is no special interpretation of any IP addresses; in
712 particular, 0.0.0.0 and ::0 are returned without modification. If any address
713 includes a port, it is set in the block. Otherwise the port value is set to
718 name the name of the option being expanded
720 Returns: a chain of ip_address_items, each containing to a textual
721 version of an IP address, and a port number (host order) or
722 zero if no port was given with the address
726 host_build_ifacelist(const uschar *list, uschar *name)
730 ip_address_item * yield = NULL, * last = NULL, * next;
732 while ((s = string_nextinlist(&list, &sep, NULL, 0)))
735 int port = host_address_extract_port(s); /* Leaves just the IP address */
737 if (!(ipv = string_is_ip_address(s, NULL)))
738 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "Malformed IP address \"%s\" in %s",
741 /* Skip IPv6 addresses if IPv6 is disabled. */
743 if (disable_ipv6 && ipv == 6) continue;
745 /* This use of strcpy() is OK because we have checked that s is a valid IP
746 address above. The field in the ip_address_item is large enough to hold an
749 next = store_get(sizeof(ip_address_item));
751 Ustrcpy(next->address, s);
753 next->v6_include_v4 = FALSE;
771 /*************************************************
772 * Find addresses on local interfaces *
773 *************************************************/
775 /* This function finds the addresses of local IP interfaces. These are used
776 when testing for routing to the local host. As the function may be called more
777 than once, the list is preserved in permanent store, pointed to by a static
778 variable, to save doing the work more than once per process.
780 The generic list of interfaces is obtained by calling host_build_ifacelist()
781 for local_interfaces and extra_local_interfaces. This list scanned to remove
782 duplicates (which may exist with different ports - not relevant here). If
783 either of the wildcard IP addresses (0.0.0.0 and ::0) are encountered, they are
784 replaced by the appropriate (IPv4 or IPv6) list of actual local interfaces,
785 obtained from os_find_running_interfaces().
788 Returns: a chain of ip_address_items, each containing to a textual
789 version of an IP address; the port numbers are not relevant
793 /* First, a local subfunction to add an interface to a list in permanent store,
794 but only if there isn't a previous copy of that address on the list. */
796 static ip_address_item *
797 add_unique_interface(ip_address_item *list, ip_address_item *ipa)
799 ip_address_item *ipa2;
800 for (ipa2 = list; ipa2; ipa2 = ipa2->next)
801 if (Ustrcmp(ipa2->address, ipa->address) == 0) return list;
802 ipa2 = store_get_perm(sizeof(ip_address_item));
809 /* This is the globally visible function */
812 host_find_interfaces(void)
814 ip_address_item *running_interfaces = NULL;
816 if (local_interface_data == NULL)
818 void *reset_item = store_get(0);
819 ip_address_item *dlist = host_build_ifacelist(CUS local_interfaces,
820 US"local_interfaces");
821 ip_address_item *xlist = host_build_ifacelist(CUS extra_local_interfaces,
822 US"extra_local_interfaces");
823 ip_address_item *ipa;
825 if (!dlist) dlist = xlist;
828 for (ipa = dlist; ipa->next; ipa = ipa->next) ;
832 for (ipa = dlist; ipa; ipa = ipa->next)
834 if (Ustrcmp(ipa->address, "0.0.0.0") == 0 ||
835 Ustrcmp(ipa->address, "::0") == 0)
837 BOOL ipv6 = ipa->address[0] == ':';
838 if (!running_interfaces)
839 running_interfaces = os_find_running_interfaces();
840 for (ip_address_item * ipa2 = running_interfaces; ipa2; ipa2 = ipa2->next)
841 if ((Ustrchr(ipa2->address, ':') != NULL) == ipv6)
842 local_interface_data = add_unique_interface(local_interface_data,
847 local_interface_data = add_unique_interface(local_interface_data, ipa);
850 debug_printf("Configured local interface: address=%s", ipa->address);
851 if (ipa->port != 0) debug_printf(" port=%d", ipa->port);
856 store_reset(reset_item);
859 return local_interface_data;
866 /*************************************************
867 * Convert network IP address to text *
868 *************************************************/
870 /* Given an IPv4 or IPv6 address in binary, convert it to a text
871 string and return the result in a piece of new store. The address can
872 either be given directly, or passed over in a sockaddr structure. Note
873 that this isn't the converse of host_aton() because of byte ordering
874 differences. See host_nmtoa() below.
877 type if < 0 then arg points to a sockaddr, else
878 either AF_INET or AF_INET6
879 arg points to a sockaddr if type is < 0, or
880 points to an IPv4 address (32 bits), or
881 points to an IPv6 address (128 bits),
882 in both cases, in network byte order
883 buffer if NULL, the result is returned in gotten store;
884 else points to a buffer to hold the answer
885 portptr points to where to put the port number, if non NULL; only
888 Returns: pointer to character string
892 host_ntoa(int type, const void *arg, uschar *buffer, int *portptr)
896 /* The new world. It is annoying that we have to fish out the address from
897 different places in the block, depending on what kind of address it is. It
898 is also a pain that inet_ntop() returns a const uschar *, whereas the IPv4
899 function inet_ntoa() returns just uschar *, and some picky compilers insist
900 on warning if one assigns a const uschar * to a uschar *. Hence the casts. */
903 uschar addr_buffer[46];
906 int family = ((struct sockaddr *)arg)->sa_family;
907 if (family == AF_INET6)
909 struct sockaddr_in6 *sk = (struct sockaddr_in6 *)arg;
910 yield = US inet_ntop(family, &(sk->sin6_addr), CS addr_buffer,
911 sizeof(addr_buffer));
912 if (portptr != NULL) *portptr = ntohs(sk->sin6_port);
916 struct sockaddr_in *sk = (struct sockaddr_in *)arg;
917 yield = US inet_ntop(family, &(sk->sin_addr), CS addr_buffer,
918 sizeof(addr_buffer));
919 if (portptr != NULL) *portptr = ntohs(sk->sin_port);
924 yield = US inet_ntop(type, arg, CS addr_buffer, sizeof(addr_buffer));
927 /* If the result is a mapped IPv4 address, show it in V4 format. */
929 if (Ustrncmp(yield, "::ffff:", 7) == 0) yield += 7;
931 #else /* HAVE_IPV6 */
937 yield = US inet_ntoa(((struct sockaddr_in *)arg)->sin_addr);
938 if (portptr != NULL) *portptr = ntohs(((struct sockaddr_in *)arg)->sin_port);
941 yield = US inet_ntoa(*((struct in_addr *)arg));
944 /* If there is no buffer, put the string into some new store. */
946 if (buffer == NULL) return string_copy(yield);
948 /* Callers of this function with a non-NULL buffer must ensure that it is
949 large enough to hold an IPv6 address, namely, at least 46 bytes. That's what
950 makes this use of strcpy() OK. */
952 Ustrcpy(buffer, yield);
959 /*************************************************
960 * Convert address text to binary *
961 *************************************************/
963 /* Given the textual form of an IP address, convert it to binary in an
964 array of ints. IPv4 addresses occupy one int; IPv6 addresses occupy 4 ints.
965 The result has the first byte in the most significant byte of the first int. In
966 other words, the result is not in network byte order, but in host byte order.
967 As a result, this is not the converse of host_ntoa(), which expects network
968 byte order. See host_nmtoa() below.
971 address points to the textual address, checked for syntax
972 bin points to an array of 4 ints
974 Returns: the number of ints used
978 host_aton(const uschar *address, int *bin)
983 /* Handle IPv6 address, which may end with an IPv4 address. It may also end
984 with a "scope", introduced by a percent sign. This code is NOT enclosed in #if
985 HAVE_IPV6 in order that IPv6 addresses are recognized even if IPv6 is not
988 if (Ustrchr(address, ':') != NULL)
990 const uschar *p = address;
991 const uschar *component[8];
992 BOOL ipv4_ends = FALSE;
998 /* If the address starts with a colon, it will start with two colons.
999 Just lose the first one, which will leave a null first component. */
1003 /* Split the address into components separated by colons. The input address
1004 is supposed to be checked for syntax. There was a case where this was
1005 overlooked; to guard against that happening again, check here and crash if
1006 there are too many components. */
1008 while (*p != 0 && *p != '%')
1010 int len = Ustrcspn(p, ":%");
1011 if (len == 0) nulloffset = ci;
1012 if (ci > 7) log_write(0, LOG_MAIN|LOG_PANIC_DIE,
1013 "Internal error: invalid IPv6 address \"%s\" passed to host_aton()",
1015 component[ci++] = p;
1020 /* If the final component contains a dot, it is a trailing v4 address.
1021 As the syntax is known to be checked, just set up for a trailing
1022 v4 address and restrict the v6 part to 6 components. */
1024 if (Ustrchr(component[ci-1], '.') != NULL)
1026 address = component[--ci];
1032 /* If there are fewer than 6 or 8 components, we have to insert some
1033 more empty ones in the middle. */
1037 int insert_count = v6count - ci;
1038 for (i = v6count-1; i > nulloffset + insert_count; i--)
1039 component[i] = component[i - insert_count];
1040 while (i > nulloffset) component[i--] = US"";
1043 /* Now turn the components into binary in pairs and bung them
1044 into the vector of ints. */
1046 for (i = 0; i < v6count; i += 2)
1047 bin[i/2] = (Ustrtol(component[i], NULL, 16) << 16) +
1048 Ustrtol(component[i+1], NULL, 16);
1050 /* If there was no terminating v4 component, we are done. */
1052 if (!ipv4_ends) return 4;
1055 /* Handle IPv4 address */
1057 (void)sscanf(CS address, "%d.%d.%d.%d", x, x+1, x+2, x+3);
1058 bin[v4offset] = ((uint)x[0] << 24) + (x[1] << 16) + (x[2] << 8) + x[3];
1063 /*************************************************
1064 * Apply mask to an IP address *
1065 *************************************************/
1067 /* Mask an address held in 1 or 4 ints, with the ms bit in the ms bit of the
1071 count the number of ints
1072 binary points to the ints to be masked
1073 mask the count of ms bits to leave, or -1 if no masking
1079 host_mask(int count, int *binary, int mask)
1081 if (mask < 0) mask = 99999;
1082 for (int i = 0; i < count; i++)
1085 if (mask == 0) wordmask = 0;
1088 wordmask = (uint)(-1) << (32 - mask);
1096 binary[i] &= wordmask;
1103 /*************************************************
1104 * Convert masked IP address in ints to text *
1105 *************************************************/
1107 /* We can't use host_ntoa() because it assumes the binary values are in network
1108 byte order, and these are the result of host_aton(), which puts them in ints in
1109 host byte order. Also, we really want IPv6 addresses to be in a canonical
1110 format, so we output them with no abbreviation. In a number of cases we can't
1111 use the normal colon separator in them because it terminates keys in lsearch
1112 files, so we want to use dot instead. There's an argument that specifies what
1113 to use for IPv6 addresses.
1116 count 1 or 4 (number of ints)
1117 binary points to the ints
1118 mask mask value; if < 0 don't add to result
1119 buffer big enough to hold the result
1120 sep component separator character for IPv6 addresses
1122 Returns: the number of characters placed in buffer, not counting
1127 host_nmtoa(int count, int *binary, int mask, uschar *buffer, int sep)
1130 uschar *tt = buffer;
1135 for (int i = 24; i >= 0; i -= 8)
1136 tt += sprintf(CS tt, "%d.", (j >> i) & 255);
1139 for (int i = 0; i < 4; i++)
1142 tt += sprintf(CS tt, "%04x%c%04x%c", (j >> 16) & 0xffff, sep, j & 0xffff, sep);
1145 tt--; /* lose final separator */
1150 tt += sprintf(CS tt, "/%d", mask);
1156 /* Like host_nmtoa() but: ipv6-only, canonical output, no mask
1159 binary points to the ints
1160 buffer big enough to hold the result
1162 Returns: the number of characters placed in buffer, not counting
1167 ipv6_nmtoa(int * binary, uschar * buffer)
1170 uschar * c = buffer;
1171 uschar * d = NULL; /* shut insufficiently "clever" compiler up */
1173 for (i = 0; i < 4; i++)
1174 { /* expand to text */
1176 c += sprintf(CS c, "%x:%x:", (j >> 16) & 0xffff, j & 0xffff);
1179 for (c = buffer, k = -1, i = 0; i < 8; i++)
1180 { /* find longest 0-group sequence */
1181 if (*c == '0') /* must be "0:" */
1185 while (c[2] == '0') i++, c += 2;
1188 k = i-j; /* length of sequence */
1189 d = s; /* start of sequence */
1192 while (*++c != ':') ;
1196 c[-1] = '\0'; /* drop trailing colon */
1198 /* debug_printf("%s: D k %d <%s> <%s>\n", __FUNCTION__, k, d, d + 2*(k+1)); */
1202 if (d == buffer) c--; /* need extra colon */
1203 *d++ = ':'; /* 1st 0 */
1204 while ((*d++ = *c++)) ;
1214 /*************************************************
1215 * Check port for tls_on_connect *
1216 *************************************************/
1218 /* This function checks whether a given incoming port is configured for tls-
1219 on-connect. It is called from the daemon and from inetd handling. If the global
1220 option tls_on_connect is already set, all ports operate this way. Otherwise, we
1221 check the tls_on_connect_ports option for a list of ports.
1223 Argument: a port number
1224 Returns: TRUE or FALSE
1228 host_is_tls_on_connect_port(int port)
1232 const uschar *list = tls_in.on_connect_ports;
1236 if (tls_in.on_connect) return TRUE;
1238 while ((s = string_nextinlist(&list, &sep, buffer, sizeof(buffer))))
1239 if (Ustrtol(s, &end, 10) == port)
1247 /*************************************************
1248 * Check whether host is in a network *
1249 *************************************************/
1251 /* This function checks whether a given IP address matches a pattern that
1252 represents either a single host, or a network (using CIDR notation). The caller
1253 of this function must check the syntax of the arguments before calling it.
1256 host string representation of the ip-address to check
1257 net string representation of the network, with optional CIDR mask
1258 maskoffset offset to the / that introduces the mask in the key
1259 zero if there is no mask
1262 TRUE the host is inside the network
1263 FALSE the host is NOT inside the network
1267 host_is_in_net(const uschar *host, const uschar *net, int maskoffset)
1272 int size = host_aton(net, address);
1275 /* No mask => all bits to be checked */
1277 if (maskoffset == 0) mlen = 99999; /* Big number */
1278 else mlen = Uatoi(net + maskoffset + 1);
1280 /* Convert the incoming address to binary. */
1282 insize = host_aton(host, incoming);
1284 /* Convert IPv4 addresses given in IPv6 compatible mode, which represent
1285 connections from IPv4 hosts to IPv6 hosts, that is, addresses of the form
1286 ::ffff:<v4address>, to IPv4 format. */
1288 if (insize == 4 && incoming[0] == 0 && incoming[1] == 0 &&
1289 incoming[2] == 0xffff)
1292 incoming[0] = incoming[3];
1295 /* No match if the sizes don't agree. */
1297 if (insize != size) return FALSE;
1299 /* Else do the masked comparison. */
1301 for (int i = 0; i < size; i++)
1304 if (mlen == 0) mask = 0;
1307 mask = (uint)(-1) << (32 - mlen);
1315 if ((incoming[i] & mask) != (address[i] & mask)) return FALSE;
1323 /*************************************************
1324 * Scan host list for local hosts *
1325 *************************************************/
1327 /* Scan through a chain of addresses and check whether any of them is the
1328 address of an interface on the local machine. If so, remove that address and
1329 any previous ones with the same MX value, and all subsequent ones (which will
1330 have greater or equal MX values) from the chain. Note: marking them as unusable
1331 is NOT the right thing to do because it causes the hosts not to be used for
1332 other domains, for which they may well be correct.
1334 The hosts may be part of a longer chain; we only process those between the
1335 initial pointer and the "last" pointer.
1337 There is also a list of "pseudo-local" host names which are checked against the
1338 host names. Any match causes that host item to be treated the same as one which
1339 matches a local IP address.
1341 If the very first host is a local host, then all MX records had a precedence
1342 greater than or equal to that of the local host. Either there's a problem in
1343 the DNS, or an apparently remote name turned out to be an abbreviation for the
1344 local host. Give a specific return code, and let the caller decide what to do.
1345 Otherwise, give a success code if at least one host address has been found.
1348 host pointer to the first host in the chain
1349 lastptr pointer to pointer to the last host in the chain (may be updated)
1350 removed if not NULL, set TRUE if some local addresses were removed
1354 HOST_FOUND if there is at least one host with an IP address on the chain
1355 and an MX value less than any MX value associated with the
1357 HOST_FOUND_LOCAL if a local host is among the lowest-numbered MX hosts; when
1358 the host addresses were obtained from A records or
1359 gethostbyname(), the MX values are set to -1.
1360 HOST_FIND_FAILED if no valid hosts with set IP addresses were found
1364 host_scan_for_local_hosts(host_item *host, host_item **lastptr, BOOL *removed)
1366 int yield = HOST_FIND_FAILED;
1367 host_item *last = *lastptr;
1368 host_item *prev = NULL;
1371 if (removed != NULL) *removed = FALSE;
1373 if (local_interface_data == NULL) local_interface_data = host_find_interfaces();
1375 for (h = host; h != last->next; h = h->next)
1378 if (hosts_treat_as_local != NULL)
1381 const uschar *save = deliver_domain;
1382 deliver_domain = h->name; /* set $domain */
1383 rc = match_isinlist(string_copylc(h->name), CUSS &hosts_treat_as_local, 0,
1384 &domainlist_anchor, NULL, MCL_DOMAIN, TRUE, NULL);
1385 deliver_domain = save;
1386 if (rc == OK) goto FOUND_LOCAL;
1390 /* It seems that on many operating systems, 0.0.0.0 is treated as a synonym
1391 for 127.0.0.1 and refers to the local host. We therefore force it always to
1392 be treated as local. */
1394 if (h->address != NULL)
1396 if (Ustrcmp(h->address, "0.0.0.0") == 0) goto FOUND_LOCAL;
1397 for (ip_address_item * ip = local_interface_data; ip; ip = ip->next)
1398 if (Ustrcmp(h->address, ip->address) == 0) goto FOUND_LOCAL;
1399 yield = HOST_FOUND; /* At least one remote address has been found */
1402 /* Update prev to point to the last host item before any that have
1403 the same MX value as the one we have just considered. */
1405 if (h->next == NULL || h->next->mx != h->mx) prev = h;
1408 return yield; /* No local hosts found: return HOST_FOUND or HOST_FIND_FAILED */
1410 /* A host whose IP address matches a local IP address, or whose name matches
1411 something in hosts_treat_as_local has been found. */
1417 HDEBUG(D_host_lookup) debug_printf((h->mx >= 0)?
1418 "local host has lowest MX\n" :
1419 "local host found for non-MX address\n");
1420 return HOST_FOUND_LOCAL;
1423 HDEBUG(D_host_lookup)
1425 debug_printf("local host in host list - removed hosts:\n");
1426 for (h = prev->next; h != last->next; h = h->next)
1427 debug_printf(" %s %s %d\n", h->name, h->address, h->mx);
1430 if (removed != NULL) *removed = TRUE;
1431 prev->next = last->next;
1439 /*************************************************
1440 * Remove duplicate IPs in host list *
1441 *************************************************/
1443 /* You would think that administrators could set up their DNS records so that
1444 one ended up with a list of unique IP addresses after looking up A or MX
1445 records, but apparently duplication is common. So we scan such lists and
1446 remove the later duplicates. Note that we may get lists in which some host
1447 addresses are not set.
1450 host pointer to the first host in the chain
1451 lastptr pointer to pointer to the last host in the chain (may be updated)
1457 host_remove_duplicates(host_item *host, host_item **lastptr)
1459 while (host != *lastptr)
1461 if (host->address != NULL)
1463 host_item *h = host;
1464 while (h != *lastptr)
1466 if (h->next->address != NULL &&
1467 Ustrcmp(h->next->address, host->address) == 0)
1469 DEBUG(D_host_lookup) debug_printf("duplicate IP address %s (MX=%d) "
1470 "removed\n", host->address, h->next->mx);
1471 if (h->next == *lastptr) *lastptr = h;
1472 h->next = h->next->next;
1477 /* If the last item was removed, host may have become == *lastptr */
1478 if (host != *lastptr) host = host->next;
1485 /*************************************************
1486 * Find sender host name by gethostbyaddr() *
1487 *************************************************/
1489 /* This used to be the only way it was done, but it turns out that not all
1490 systems give aliases for calls to gethostbyaddr() - or one of the modern
1491 equivalents like getipnodebyaddr(). Fortunately, multiple PTR records are rare,
1492 but they can still exist. This function is now used only when a DNS lookup of
1493 the IP address fails, in order to give access to /etc/hosts.
1496 Returns: OK, DEFER, FAIL
1500 host_name_lookup_byaddr(void)
1504 struct hostent *hosts;
1505 struct in_addr addr;
1506 unsigned long time_msec = 0; /* init to quieten dumb static analysis */
1508 if (slow_lookup_log) time_msec = get_time_in_ms();
1510 /* Lookup on IPv6 system */
1513 if (Ustrchr(sender_host_address, ':') != NULL)
1515 struct in6_addr addr6;
1516 if (inet_pton(AF_INET6, CS sender_host_address, &addr6) != 1)
1517 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "unable to parse \"%s\" as an "
1518 "IPv6 address", sender_host_address);
1519 #if HAVE_GETIPNODEBYADDR
1520 hosts = getipnodebyaddr(CS &addr6, sizeof(addr6), AF_INET6, &h_errno);
1522 hosts = gethostbyaddr(CS &addr6, sizeof(addr6), AF_INET6);
1527 if (inet_pton(AF_INET, CS sender_host_address, &addr) != 1)
1528 log_write(0, LOG_MAIN|LOG_PANIC_DIE, "unable to parse \"%s\" as an "
1529 "IPv4 address", sender_host_address);
1530 #if HAVE_GETIPNODEBYADDR
1531 hosts = getipnodebyaddr(CS &addr, sizeof(addr), AF_INET, &h_errno);
1533 hosts = gethostbyaddr(CS &addr, sizeof(addr), AF_INET);
1537 /* Do lookup on IPv4 system */
1540 addr.s_addr = (S_ADDR_TYPE)inet_addr(CS sender_host_address);
1541 hosts = gethostbyaddr(CS(&addr), sizeof(addr), AF_INET);
1544 if ( slow_lookup_log
1545 && (time_msec = get_time_in_ms() - time_msec) > slow_lookup_log
1547 log_long_lookup(US"name", sender_host_address, time_msec);
1549 /* Failed to look up the host. */
1553 HDEBUG(D_host_lookup) debug_printf("IP address lookup failed: h_errno=%d\n",
1555 return (h_errno == TRY_AGAIN || h_errno == NO_RECOVERY) ? DEFER : FAIL;
1558 /* It seems there are some records in the DNS that yield an empty name. We
1559 treat this as non-existent. In some operating systems, this is returned as an
1560 empty string; in others as a single dot. */
1562 if (hosts->h_name == NULL || hosts->h_name[0] == 0 || hosts->h_name[0] == '.')
1564 HDEBUG(D_host_lookup) debug_printf("IP address lookup yielded an empty name: "
1565 "treated as non-existent host name\n");
1569 /* Copy and lowercase the name, which is in static storage in many systems.
1570 Put it in permanent memory. */
1572 s = US hosts->h_name;
1573 len = Ustrlen(s) + 1;
1574 t = sender_host_name = store_get_perm(len);
1575 while (*s != 0) *t++ = tolower(*s++);
1578 /* If the host has aliases, build a copy of the alias list */
1580 if (hosts->h_aliases)
1584 for (uschar ** aliases = USS hosts->h_aliases; *aliases; aliases++) count++;
1585 ptr = sender_host_aliases = store_get_perm(count * sizeof(uschar *));
1586 for (uschar ** aliases = USS hosts->h_aliases; *aliases; aliases++)
1588 uschar *s = *aliases;
1589 int len = Ustrlen(s) + 1;
1590 uschar *t = *ptr++ = store_get_perm(len);
1591 while (*s != 0) *t++ = tolower(*s++);
1602 /*************************************************
1603 * Find host name for incoming call *
1604 *************************************************/
1606 /* Put the name in permanent store, pointed to by sender_host_name. We also set
1607 up a list of alias names, pointed to by sender_host_alias. The list is
1608 NULL-terminated. The incoming address is in sender_host_address, either in
1609 dotted-quad form for IPv4 or in colon-separated form for IPv6.
1611 This function does a thorough check that the names it finds point back to the
1612 incoming IP address. Any that do not are discarded. Note that this is relied on
1613 by the ACL reverse_host_lookup check.
1615 On some systems, get{host,ipnode}byaddr() appears to do this internally, but
1616 this it not universally true. Also, for release 4.30, this function was changed
1617 to do a direct DNS lookup first, by default[1], because it turns out that that
1618 is the only guaranteed way to find all the aliases on some systems. My
1619 experiments indicate that Solaris gethostbyaddr() gives the aliases for but
1622 [1] The actual order is controlled by the host_lookup_order option.
1625 Returns: OK on success, the answer being placed in the global variable
1626 sender_host_name, with any aliases in a list hung off
1628 FAIL if no host name can be found
1629 DEFER if a temporary error was encountered
1631 The variable host_lookup_msg is set to an empty string on success, or to a
1632 reason for the failure otherwise, in a form suitable for tagging onto an error
1633 message, and also host_lookup_failed is set TRUE if the lookup failed. If there
1634 was a defer, host_lookup_deferred is set TRUE.
1636 Any dynamically constructed string for host_lookup_msg must be in permanent
1637 store, because it might be used for several incoming messages on the same SMTP
1641 host_name_lookup(void)
1645 uschar *save_hostname;
1649 const uschar *list = host_lookup_order;
1653 sender_host_dnssec = host_lookup_deferred = host_lookup_failed = FALSE;
1655 HDEBUG(D_host_lookup)
1656 debug_printf("looking up host name for %s\n", sender_host_address);
1658 /* For testing the case when a lookup does not complete, we have a special
1659 reserved IP address. */
1661 if (f.running_in_test_harness &&
1662 Ustrcmp(sender_host_address, "99.99.99.99") == 0)
1664 HDEBUG(D_host_lookup)
1665 debug_printf("Test harness: host name lookup returns DEFER\n");
1666 host_lookup_deferred = TRUE;
1670 /* Do lookups directly in the DNS or via gethostbyaddr() (or equivalent), in
1671 the order specified by the host_lookup_order option. */
1673 while ((ordername = string_nextinlist(&list, &sep, buffer, sizeof(buffer))))
1675 if (strcmpic(ordername, US"bydns") == 0)
1677 dns_init(FALSE, FALSE, FALSE); /* dnssec ctrl by dns_dnssec_ok glbl */
1678 dns_build_reverse(sender_host_address, buffer);
1679 rc = dns_lookup_timerwrap(&dnsa, buffer, T_PTR, NULL);
1681 /* The first record we come across is used for the name; others are
1682 considered to be aliases. We have to scan twice, in order to find out the
1683 number of aliases. However, if all the names are empty, we will behave as
1684 if failure. (PTR records that yield empty names have been encountered in
1687 if (rc == DNS_SUCCEED)
1689 uschar **aptr = NULL;
1692 int old_pool = store_pool;
1694 sender_host_dnssec = dns_is_secure(&dnsa);
1696 debug_printf("Reverse DNS security status: %s\n",
1697 sender_host_dnssec ? "DNSSEC verified (AD)" : "unverified");
1699 store_pool = POOL_PERM; /* Save names in permanent storage */
1701 for (dns_record * rr = dns_next_rr(&dnsa, &dnss, RESET_ANSWERS);
1703 rr = dns_next_rr(&dnsa, &dnss, RESET_NEXT)) if (rr->type == T_PTR)
1706 /* Get store for the list of aliases. For compatibility with
1707 gethostbyaddr, we make an empty list if there are none. */
1709 aptr = sender_host_aliases = store_get(count * sizeof(uschar *));
1711 /* Re-scan and extract the names */
1713 for (dns_record * rr = dns_next_rr(&dnsa, &dnss, RESET_ANSWERS);
1715 rr = dns_next_rr(&dnsa, &dnss, RESET_NEXT)) if (rr->type == T_PTR)
1717 uschar * s = store_get(ssize);
1719 /* If an overlong response was received, the data will have been
1720 truncated and dn_expand may fail. */
1722 if (dn_expand(dnsa.answer, dnsa.answer + dnsa.answerlen,
1723 US (rr->data), (DN_EXPAND_ARG4_TYPE)(s), ssize) < 0)
1725 log_write(0, LOG_MAIN, "host name alias list truncated for %s",
1726 sender_host_address);
1730 store_reset(s + Ustrlen(s) + 1);
1733 HDEBUG(D_host_lookup) debug_printf("IP address lookup yielded an "
1734 "empty name: treated as non-existent host name\n");
1737 if (!sender_host_name) sender_host_name = s;
1739 while (*s != 0) { *s = tolower(*s); s++; }
1742 *aptr = NULL; /* End of alias list */
1743 store_pool = old_pool; /* Reset store pool */
1745 /* If we've found a names, break out of the "order" loop */
1747 if (sender_host_name != NULL) break;
1750 /* If the DNS lookup deferred, we must also defer. */
1752 if (rc == DNS_AGAIN)
1754 HDEBUG(D_host_lookup)
1755 debug_printf("IP address PTR lookup gave temporary error\n");
1756 host_lookup_deferred = TRUE;
1761 /* Do a lookup using gethostbyaddr() - or equivalent */
1763 else if (strcmpic(ordername, US"byaddr") == 0)
1765 HDEBUG(D_host_lookup)
1766 debug_printf("IP address lookup using gethostbyaddr()\n");
1767 rc = host_name_lookup_byaddr();
1770 host_lookup_deferred = TRUE;
1771 return rc; /* Can't carry on */
1773 if (rc == OK) break; /* Found a name */
1775 } /* Loop for bydns/byaddr scanning */
1777 /* If we have failed to find a name, return FAIL and log when required.
1778 NB host_lookup_msg must be in permanent store. */
1780 if (!sender_host_name)
1782 if (host_checking || !f.log_testing_mode)
1783 log_write(L_host_lookup_failed, LOG_MAIN, "no host name found for IP "
1784 "address %s", sender_host_address);
1785 host_lookup_msg = US" (failed to find host name from IP address)";
1786 host_lookup_failed = TRUE;
1790 HDEBUG(D_host_lookup)
1792 uschar **aliases = sender_host_aliases;
1793 debug_printf("IP address lookup yielded \"%s\"\n", sender_host_name);
1794 while (*aliases != NULL) debug_printf(" alias \"%s\"\n", *aliases++);
1797 /* We need to verify that a forward lookup on the name we found does indeed
1798 correspond to the address. This is for security: in principle a malefactor who
1799 happened to own a reverse zone could set it to point to any names at all.
1801 This code was present in versions of Exim before 3.20. At that point I took it
1802 out because I thought that gethostbyaddr() did the check anyway. It turns out
1803 that this isn't always the case, so it's coming back in at 4.01. This version
1804 is actually better, because it also checks aliases.
1806 The code was made more robust at release 4.21. Prior to that, it accepted all
1807 the names if any of them had the correct IP address. Now the code checks all
1808 the names, and accepts only those that have the correct IP address. */
1810 save_hostname = sender_host_name; /* Save for error messages */
1811 aliases = sender_host_aliases;
1812 for (uschar * hname = sender_host_name; hname; hname = *aliases++)
1816 host_item h = { .next = NULL, .name = hname, .mx = MX_NONE, .address = NULL };
1818 { .request = sender_host_dnssec ? US"*" : NULL, .require = NULL };
1820 if ( (rc = host_find_bydns(&h, NULL, HOST_FIND_BY_A | HOST_FIND_BY_AAAA,
1821 NULL, NULL, NULL, &d, NULL, NULL)) == HOST_FOUND
1822 || rc == HOST_FOUND_LOCAL
1825 HDEBUG(D_host_lookup) debug_printf("checking addresses for %s\n", hname);
1827 /* If the forward lookup was not secure we cancel the is-secure variable */
1829 DEBUG(D_dns) debug_printf("Forward DNS security status: %s\n",
1830 h.dnssec == DS_YES ? "DNSSEC verified (AD)" : "unverified");
1831 if (h.dnssec != DS_YES) sender_host_dnssec = FALSE;
1833 for (host_item * hh = &h; hh; hh = hh->next)
1834 if (host_is_in_net(hh->address, sender_host_address, 0))
1836 HDEBUG(D_host_lookup) debug_printf(" %s OK\n", hh->address);
1841 HDEBUG(D_host_lookup) debug_printf(" %s\n", hh->address);
1843 if (!ok) HDEBUG(D_host_lookup)
1844 debug_printf("no IP address for %s matched %s\n", hname,
1845 sender_host_address);
1847 else if (rc == HOST_FIND_AGAIN)
1849 HDEBUG(D_host_lookup) debug_printf("temporary error for host name lookup\n");
1850 host_lookup_deferred = TRUE;
1851 sender_host_name = NULL;
1855 HDEBUG(D_host_lookup) debug_printf("no IP addresses found for %s\n", hname);
1857 /* If this name is no good, and it's the sender name, set it null pro tem;
1858 if it's an alias, just remove it from the list. */
1862 if (hname == sender_host_name) sender_host_name = NULL; else
1864 uschar **a; /* Don't amalgamate - some */
1865 a = --aliases; /* compilers grumble */
1866 while (*a != NULL) { *a = a[1]; a++; }
1871 /* If sender_host_name == NULL, it means we didn't like the name. Replace
1872 it with the first alias, if there is one. */
1874 if (sender_host_name == NULL && *sender_host_aliases != NULL)
1875 sender_host_name = *sender_host_aliases++;
1877 /* If we now have a main name, all is well. */
1879 if (sender_host_name != NULL) return OK;
1881 /* We have failed to find an address that matches. */
1883 HDEBUG(D_host_lookup)
1884 debug_printf("%s does not match any IP address for %s\n",
1885 sender_host_address, save_hostname);
1887 /* This message must be in permanent store */
1889 old_pool = store_pool;
1890 store_pool = POOL_PERM;
1891 host_lookup_msg = string_sprintf(" (%s does not match any IP address for %s)",
1892 sender_host_address, save_hostname);
1893 store_pool = old_pool;
1894 host_lookup_failed = TRUE;
1901 /*************************************************
1902 * Find IP address(es) for host by name *
1903 *************************************************/
1905 /* The input is a host_item structure with the name filled in and the address
1906 field set to NULL. We use gethostbyname() or getipnodebyname() or
1907 gethostbyname2(), as appropriate. Of course, these functions may use the DNS,
1908 but they do not do MX processing. It appears, however, that in some systems the
1909 current setting of resolver options is used when one of these functions calls
1910 the resolver. For this reason, we call dns_init() at the start, with arguments
1911 influenced by bits in "flags", just as we do for host_find_bydns().
1913 The second argument provides a host list (usually an IP list) of hosts to
1914 ignore. This makes it possible to ignore IPv6 link-local addresses or loopback
1915 addresses in unreasonable places.
1917 The lookup may result in a change of name. For compatibility with the dns
1918 lookup, return this via fully_qualified_name as well as updating the host item.
1919 The lookup may also yield more than one IP address, in which case chain on
1920 subsequent host_item structures.
1923 host a host item with the name and MX filled in;
1924 the address is to be filled in;
1925 multiple IP addresses cause other host items to be
1927 ignore_target_hosts a list of hosts to ignore
1928 flags HOST_FIND_QUALIFY_SINGLE ) passed to
1929 HOST_FIND_SEARCH_PARENTS ) dns_init()
1930 fully_qualified_name if not NULL, set to point to host name for
1931 compatibility with host_find_bydns
1932 local_host_check TRUE if a check for the local host is wanted
1934 Returns: HOST_FIND_FAILED Failed to find the host or domain
1935 HOST_FIND_AGAIN Try again later
1936 HOST_FOUND Host found - data filled in
1937 HOST_FOUND_LOCAL Host found and is the local host
1941 host_find_byname(host_item *host, const uschar *ignore_target_hosts, int flags,
1942 const uschar **fully_qualified_name, BOOL local_host_check)
1945 host_item *last = NULL;
1946 BOOL temp_error = FALSE;
1951 /* Make sure DNS options are set as required. This appears to be necessary in
1952 some circumstances when the get..byname() function actually calls the DNS. */
1954 dns_init((flags & HOST_FIND_QUALIFY_SINGLE) != 0,
1955 (flags & HOST_FIND_SEARCH_PARENTS) != 0,
1956 FALSE); /* Cannot retrieve dnssec status so do not request */
1958 /* In an IPv6 world, unless IPv6 has been disabled, we need to scan for both
1959 kinds of address, so go round the loop twice. Note that we have ensured that
1960 AF_INET6 is defined even in an IPv4 world, which makes for slightly tidier
1961 code. However, if dns_ipv4_lookup matches the domain, we also just do IPv4
1962 lookups here (except when testing standalone). */
1969 (dns_ipv4_lookup != NULL &&
1970 match_isinlist(host->name, CUSS &dns_ipv4_lookup, 0, NULL, NULL,
1971 MCL_DOMAIN, TRUE, NULL) == OK))
1974 { af = AF_INET; times = 1; }
1976 { af = AF_INET6; times = 2; }
1978 /* No IPv6 support */
1980 #else /* HAVE_IPV6 */
1982 #endif /* HAVE_IPV6 */
1984 /* Initialize the flag that gets set for DNS syntax check errors, so that the
1985 interface to this function can be similar to host_find_bydns. */
1987 f.host_find_failed_syntax = FALSE;
1989 /* Loop to look up both kinds of address in an IPv6 world */
1991 for (int i = 1; i <= times;
1993 af = AF_INET, /* If 2 passes, IPv4 on the second */
1999 struct hostent *hostdata;
2000 unsigned long time_msec = 0; /* compiler quietening */
2003 printf("Looking up: %s\n", host->name);
2006 if (slow_lookup_log) time_msec = get_time_in_ms();
2009 if (f.running_in_test_harness)
2010 hostdata = host_fake_gethostbyname(host->name, af, &error_num);
2013 #if HAVE_GETIPNODEBYNAME
2014 hostdata = getipnodebyname(CS host->name, af, 0, &error_num);
2016 hostdata = gethostbyname2(CS host->name, af);
2017 error_num = h_errno;
2021 #else /* not HAVE_IPV6 */
2022 if (f.running_in_test_harness)
2023 hostdata = host_fake_gethostbyname(host->name, AF_INET, &error_num);
2026 hostdata = gethostbyname(CS host->name);
2027 error_num = h_errno;
2029 #endif /* HAVE_IPV6 */
2031 if ( slow_lookup_log
2032 && (time_msec = get_time_in_ms() - time_msec) > slow_lookup_log)
2033 log_long_lookup(US"name", host->name, time_msec);
2035 if (hostdata == NULL)
2040 case HOST_NOT_FOUND: error = US"HOST_NOT_FOUND"; break;
2041 case TRY_AGAIN: error = US"TRY_AGAIN"; break;
2042 case NO_RECOVERY: error = US"NO_RECOVERY"; break;
2043 case NO_DATA: error = US"NO_DATA"; break;
2044 #if NO_DATA != NO_ADDRESS
2045 case NO_ADDRESS: error = US"NO_ADDRESS"; break;
2047 default: error = US"?"; break;
2050 DEBUG(D_host_lookup) debug_printf("%s returned %d (%s)\n",
2052 #if HAVE_GETIPNODEBYNAME
2053 (af == AF_INET6)? "getipnodebyname(af=inet6)" : "getipnodebyname(af=inet)",
2055 (af == AF_INET6)? "gethostbyname2(af=inet6)" : "gethostbyname2(af=inet)",
2062 if (error_num == TRY_AGAIN || error_num == NO_RECOVERY) temp_error = TRUE;
2065 if ((hostdata->h_addr_list)[0] == NULL) continue;
2067 /* Replace the name with the fully qualified one if necessary, and fill in
2068 the fully_qualified_name pointer. */
2070 if (hostdata->h_name[0] != 0 &&
2071 Ustrcmp(host->name, hostdata->h_name) != 0)
2072 host->name = string_copy_dnsdomain(US hostdata->h_name);
2073 if (fully_qualified_name != NULL) *fully_qualified_name = host->name;
2075 /* Get the list of addresses. IPv4 and IPv6 addresses can be distinguished
2076 by their different lengths. Scan the list, ignoring any that are to be
2077 ignored, and build a chain from the rest. */
2079 ipv4_addr = hostdata->h_length == sizeof(struct in_addr);
2081 for (uschar ** addrlist = USS hostdata->h_addr_list; *addrlist; addrlist++)
2083 uschar *text_address =
2084 host_ntoa(ipv4_addr? AF_INET:AF_INET6, *addrlist, NULL, NULL);
2087 if (ignore_target_hosts != NULL &&
2088 verify_check_this_host(&ignore_target_hosts, NULL, host->name,
2089 text_address, NULL) == OK)
2091 DEBUG(D_host_lookup)
2092 debug_printf("ignored host %s [%s]\n", host->name, text_address);
2097 /* If this is the first address, last == NULL and we put the data in the
2102 host->address = text_address;
2103 host->port = PORT_NONE;
2104 host->status = hstatus_unknown;
2105 host->why = hwhy_unknown;
2106 host->dnssec = DS_UNK;
2110 /* Else add further host item blocks for any other addresses, keeping
2115 host_item *next = store_get(sizeof(host_item));
2116 next->name = host->name;
2117 next->mx = host->mx;
2118 next->address = text_address;
2119 next->port = PORT_NONE;
2120 next->status = hstatus_unknown;
2121 next->why = hwhy_unknown;
2122 next->dnssec = DS_UNK;
2124 next->next = last->next;
2131 /* If no hosts were found, the address field in the original host block will be
2132 NULL. If temp_error is set, at least one of the lookups gave a temporary error,
2133 so we pass that back. */
2135 if (host->address == NULL)
2139 (message_id[0] == 0 && smtp_in != NULL)?
2140 string_sprintf("no IP address found for host %s (during %s)", host->name,
2141 smtp_get_connection_info()) :
2143 string_sprintf("no IP address found for host %s", host->name);
2145 HDEBUG(D_host_lookup) debug_printf("%s\n", msg);
2146 if (temp_error) goto RETURN_AGAIN;
2147 if (host_checking || !f.log_testing_mode)
2148 log_write(L_host_lookup_failed, LOG_MAIN, "%s", msg);
2149 return HOST_FIND_FAILED;
2152 /* Remove any duplicate IP addresses, then check to see if this is the local
2153 host if required. */
2155 host_remove_duplicates(host, &last);
2156 yield = local_host_check?
2157 host_scan_for_local_hosts(host, &last, NULL) : HOST_FOUND;
2159 HDEBUG(D_host_lookup)
2161 if (fully_qualified_name)
2162 debug_printf("fully qualified name = %s\n", *fully_qualified_name);
2163 debug_printf("%s looked up these IP addresses:\n",
2165 #if HAVE_GETIPNODEBYNAME
2174 for (const host_item * h = host; h != last->next; h = h->next)
2175 debug_printf(" name=%s address=%s\n", h->name,
2176 h->address ? h->address : US"<null>");
2179 /* Return the found status. */
2183 /* Handle the case when there is a temporary error. If the name matches
2184 dns_again_means_nonexist, return permanent rather than temporary failure. */
2190 const uschar *save = deliver_domain;
2191 deliver_domain = host->name; /* set $domain */
2192 rc = match_isinlist(host->name, CUSS &dns_again_means_nonexist, 0, NULL, NULL,
2193 MCL_DOMAIN, TRUE, NULL);
2194 deliver_domain = save;
2197 DEBUG(D_host_lookup) debug_printf("%s is in dns_again_means_nonexist: "
2198 "returning HOST_FIND_FAILED\n", host->name);
2199 return HOST_FIND_FAILED;
2202 return HOST_FIND_AGAIN;
2208 /*************************************************
2209 * Fill in a host address from the DNS *
2210 *************************************************/
2212 /* Given a host item, with its name, port and mx fields set, and its address
2213 field set to NULL, fill in its IP address from the DNS. If it is multi-homed,
2214 create additional host items for the additional addresses, copying all the
2215 other fields, and randomizing the order.
2217 On IPv6 systems, AAAA records are sought first, then A records.
2219 The host name may be changed if the DNS returns a different name - e.g. fully
2220 qualified or changed via CNAME. If fully_qualified_name is not NULL, dns_lookup
2221 ensures that it points to the fully qualified name. However, this is the fully
2222 qualified version of the original name; if a CNAME is involved, the actual
2223 canonical host name may be different again, and so we get it directly from the
2224 relevant RR. Note that we do NOT change the mx field of the host item in this
2225 function as it may be called to set the addresses of hosts taken from MX
2229 host points to the host item we're filling in
2230 lastptr points to pointer to last host item in a chain of
2231 host items (may be updated if host is last and gets
2232 extended because multihomed)
2233 ignore_target_hosts list of hosts to ignore
2234 allow_ip if TRUE, recognize an IP address and return it
2235 fully_qualified_name if not NULL, return fully qualified name here if
2236 the contents are different (i.e. it must be preset
2238 dnssec_request if TRUE request the AD bit
2239 dnssec_require if TRUE require the AD bit
2240 whichrrs select ipv4, ipv6 results
2242 Returns: HOST_FIND_FAILED couldn't find A record
2243 HOST_FIND_AGAIN try again later
2244 HOST_FIND_SECURITY dnssec required but not acheived
2245 HOST_FOUND found AAAA and/or A record(s)
2246 HOST_IGNORED found, but all IPs ignored
2250 set_address_from_dns(host_item *host, host_item **lastptr,
2251 const uschar *ignore_target_hosts, BOOL allow_ip,
2252 const uschar **fully_qualified_name,
2253 BOOL dnssec_request, BOOL dnssec_require, int whichrrs)
2255 host_item *thishostlast = NULL; /* Indicates not yet filled in anything */
2256 BOOL v6_find_again = FALSE;
2257 BOOL dnssec_fail = FALSE;
2260 /* If allow_ip is set, a name which is an IP address returns that value
2261 as its address. This is used for MX records when allow_mx_to_ip is set, for
2262 those sites that feel they have to flaunt the RFC rules. */
2264 if (allow_ip && string_is_ip_address(host->name, NULL) != 0)
2267 if ( ignore_target_hosts
2268 && verify_check_this_host(&ignore_target_hosts, NULL, host->name,
2269 host->name, NULL) == OK)
2270 return HOST_IGNORED;
2273 host->address = host->name;
2277 /* On an IPv6 system, unless IPv6 is disabled, go round the loop up to twice,
2278 looking for AAAA records the first time. However, unless doing standalone
2279 testing, we force an IPv4 lookup if the domain matches dns_ipv4_lookup global.
2280 On an IPv4 system, go round the loop once only, looking only for A records. */
2285 || !(whichrrs & HOST_FIND_BY_AAAA)
2287 && match_isinlist(host->name, CUSS &dns_ipv4_lookup, 0, NULL, NULL,
2288 MCL_DOMAIN, TRUE, NULL) == OK)
2290 i = 0; /* look up A records only */
2292 #endif /* STAND_ALONE */
2294 i = 1; /* look up AAAA and A records */
2296 /* The IPv4 world */
2298 #else /* HAVE_IPV6 */
2299 i = 0; /* look up A records only */
2300 #endif /* HAVE_IPV6 */
2304 static int types[] = { T_A, T_AAAA };
2305 int type = types[i];
2306 int randoffset = i == (whichrrs & HOST_FIND_IPV4_FIRST ? 1 : 0)
2307 ? 500 : 0; /* Ensures v6/4 sort order */
2311 int rc = dns_lookup_timerwrap(&dnsa, host->name, type, fully_qualified_name);
2312 lookup_dnssec_authenticated = !dnssec_request ? NULL
2313 : dns_is_secure(&dnsa) ? US"yes" : US"no";
2316 if ( (dnssec_request || dnssec_require)
2317 && !dns_is_secure(&dnsa)
2320 debug_printf("DNS lookup of %.256s (A/AAAA) requested AD, but got AA\n", host->name);
2322 /* We want to return HOST_FIND_AGAIN if one of the A or AAAA lookups
2323 fails or times out, but not if another one succeeds. (In the early
2324 IPv6 days there are name servers that always fail on AAAA, but are happy
2325 to give out an A record. We want to proceed with that A record.) */
2327 if (rc != DNS_SUCCEED)
2329 if (i == 0) /* Just tried for an A record, i.e. end of loop */
2331 if (host->address != NULL) return HOST_FOUND; /* AAAA was found */
2332 if (rc == DNS_AGAIN || rc == DNS_FAIL || v6_find_again)
2333 return HOST_FIND_AGAIN;
2334 return HOST_FIND_FAILED; /* DNS_NOMATCH or DNS_NODATA */
2337 /* Tried for an AAAA record: remember if this was a temporary
2338 error, and look for the next record type. */
2340 if (rc != DNS_NOMATCH && rc != DNS_NODATA) v6_find_again = TRUE;
2346 if (dns_is_secure(&dnsa))
2348 DEBUG(D_host_lookup) debug_printf("%s A DNSSEC\n", host->name);
2349 if (host->dnssec == DS_UNK) /* set in host_find_bydns() */
2350 host->dnssec = DS_YES;
2357 DEBUG(D_host_lookup) debug_printf("dnssec fail on %s for %.256s",
2358 i>0 ? "AAAA" : "A", host->name);
2361 if (host->dnssec == DS_YES) /* set in host_find_bydns() */
2363 DEBUG(D_host_lookup) debug_printf("%s A cancel DNSSEC\n", host->name);
2364 host->dnssec = DS_NO;
2365 lookup_dnssec_authenticated = US"no";
2370 /* Lookup succeeded: fill in the given host item with the first non-ignored
2371 address found; create additional items for any others. A single A6 record
2372 may generate more than one address. The lookup had a chance to update the
2373 fqdn; we do not want any later times round the loop to do so. */
2375 fully_qualified_name = NULL;
2377 for (dns_record * rr = dns_next_rr(&dnsa, &dnss, RESET_ANSWERS);
2379 rr = dns_next_rr(&dnsa, &dnss, RESET_NEXT)) if (rr->type == type)
2381 dns_address * da = dns_address_from_rr(&dnsa, rr);
2383 DEBUG(D_host_lookup)
2384 if (!da) debug_printf("no addresses extracted from A6 RR for %s\n",
2387 /* This loop runs only once for A and AAAA records, but may run
2388 several times for an A6 record that generated multiple addresses. */
2390 for (; da; da = da->next)
2393 if (ignore_target_hosts != NULL &&
2394 verify_check_this_host(&ignore_target_hosts, NULL,
2395 host->name, da->address, NULL) == OK)
2397 DEBUG(D_host_lookup)
2398 debug_printf("ignored host %s [%s]\n", host->name, da->address);
2403 /* If this is the first address, stick it in the given host block,
2404 and change the name if the returned RR has a different name. */
2406 if (thishostlast == NULL)
2408 if (strcmpic(host->name, rr->name) != 0)
2409 host->name = string_copy_dnsdomain(rr->name);
2410 host->address = da->address;
2411 host->sort_key = host->mx * 1000 + random_number(500) + randoffset;
2412 host->status = hstatus_unknown;
2413 host->why = hwhy_unknown;
2414 thishostlast = host;
2417 /* Not the first address. Check for, and ignore, duplicates. Then
2418 insert in the chain at a random point. */
2425 /* End of our local chain is specified by "thishostlast". */
2427 for (next = host;; next = next->next)
2429 if (Ustrcmp(CS da->address, next->address) == 0) break;
2430 if (next == thishostlast) { next = NULL; break; }
2432 if (next != NULL) continue; /* With loop for next address */
2434 /* Not a duplicate */
2436 new_sort_key = host->mx * 1000 + random_number(500) + randoffset;
2437 next = store_get(sizeof(host_item));
2439 /* New address goes first: insert the new block after the first one
2440 (so as not to disturb the original pointer) but put the new address
2441 in the original block. */
2443 if (new_sort_key < host->sort_key)
2445 *next = *host; /* Copies port */
2447 host->address = da->address;
2448 host->sort_key = new_sort_key;
2449 if (thishostlast == host) thishostlast = next; /* Local last */
2450 if (*lastptr == host) *lastptr = next; /* Global last */
2453 /* Otherwise scan down the addresses for this host to find the
2454 one to insert after. */
2458 host_item *h = host;
2459 while (h != thishostlast)
2461 if (new_sort_key < h->next->sort_key) break;
2464 *next = *h; /* Copies port */
2466 next->address = da->address;
2467 next->sort_key = new_sort_key;
2468 if (h == thishostlast) thishostlast = next; /* Local last */
2469 if (h == *lastptr) *lastptr = next; /* Global last */
2476 /* Control gets here only if the second lookup (the A record) succeeded.
2477 However, the address may not be filled in if it was ignored. */
2479 return host->address
2482 ? HOST_FIND_SECURITY
2489 /*************************************************
2490 * Find IP addresses and host names via DNS *
2491 *************************************************/
2493 /* The input is a host_item structure with the name field filled in and the
2494 address field set to NULL. This may be in a chain of other host items. The
2495 lookup may result in more than one IP address, in which case we must created
2496 new host blocks for the additional addresses, and insert them into the chain.
2497 The original name may not be fully qualified. Use the fully_qualified_name
2498 argument to return the official name, as returned by the resolver.
2501 host point to initial host item
2502 ignore_target_hosts a list of hosts to ignore
2503 whichrrs flags indicating which RRs to look for:
2504 HOST_FIND_BY_SRV => look for SRV
2505 HOST_FIND_BY_MX => look for MX
2506 HOST_FIND_BY_A => look for A
2507 HOST_FIND_BY_AAAA => look for AAAA
2508 also flags indicating how the lookup is done
2509 HOST_FIND_QUALIFY_SINGLE ) passed to the
2510 HOST_FIND_SEARCH_PARENTS ) resolver
2511 HOST_FIND_IPV4_FIRST => reverse usual result ordering
2512 HOST_FIND_IPV4_ONLY => MX results elide ipv6
2513 srv_service when SRV used, the service name
2514 srv_fail_domains DNS errors for these domains => assume nonexist
2515 mx_fail_domains DNS errors for these domains => assume nonexist
2516 dnssec_d.request => make dnssec request: domainlist
2517 dnssec_d.require => ditto and nonexist failures
2518 fully_qualified_name if not NULL, return fully-qualified name
2519 removed set TRUE if local host was removed from the list
2521 Returns: HOST_FIND_FAILED Failed to find the host or domain;
2522 if there was a syntax error,
2523 host_find_failed_syntax is set.
2524 HOST_FIND_AGAIN Could not resolve at this time
2525 HOST_FIND_SECURITY dnsssec required but not acheived
2526 HOST_FOUND Host found
2527 HOST_FOUND_LOCAL The lowest MX record points to this
2528 machine, if MX records were found, or
2529 an A record that was found contains
2530 an address of the local host
2534 host_find_bydns(host_item *host, const uschar *ignore_target_hosts, int whichrrs,
2535 uschar *srv_service, uschar *srv_fail_domains, uschar *mx_fail_domains,
2536 const dnssec_domains *dnssec_d,
2537 const uschar **fully_qualified_name, BOOL *removed)
2539 host_item *h, *last;
2545 BOOL dnssec_require = dnssec_d
2546 && match_isinlist(host->name, CUSS &dnssec_d->require,
2547 0, NULL, NULL, MCL_DOMAIN, TRUE, NULL) == OK;
2548 BOOL dnssec_request = dnssec_require
2550 && match_isinlist(host->name, CUSS &dnssec_d->request,
2551 0, NULL, NULL, MCL_DOMAIN, TRUE, NULL) == OK);
2552 dnssec_status_t dnssec;
2554 /* Set the default fully qualified name to the incoming name, initialize the
2555 resolver if necessary, set up the relevant options, and initialize the flag
2556 that gets set for DNS syntax check errors. */
2558 if (fully_qualified_name != NULL) *fully_qualified_name = host->name;
2559 dns_init((whichrrs & HOST_FIND_QUALIFY_SINGLE) != 0,
2560 (whichrrs & HOST_FIND_SEARCH_PARENTS) != 0,
2562 f.host_find_failed_syntax = FALSE;
2564 /* First, if requested, look for SRV records. The service name is given; we
2565 assume TCP protocol. DNS domain names are constrained to a maximum of 256
2566 characters, so the code below should be safe. */
2568 if (whichrrs & HOST_FIND_BY_SRV)
2571 uschar * temp_fully_qualified_name;
2574 g = string_fmt_append(NULL, "_%s._tcp.%n%.256s",
2575 srv_service, &prefix_length, host->name);
2576 temp_fully_qualified_name = string_from_gstring(g);
2579 /* Search for SRV records. If the fully qualified name is different to
2580 the input name, pass back the new original domain, without the prepended
2584 lookup_dnssec_authenticated = NULL;
2585 rc = dns_lookup_timerwrap(&dnsa, temp_fully_qualified_name, ind_type,
2586 CUSS &temp_fully_qualified_name);
2589 if ((dnssec_request || dnssec_require)
2590 && !dns_is_secure(&dnsa)
2591 && dns_is_aa(&dnsa))
2592 debug_printf("DNS lookup of %.256s (SRV) requested AD, but got AA\n", host->name);
2596 if (dns_is_secure(&dnsa))
2597 { dnssec = DS_YES; lookup_dnssec_authenticated = US"yes"; }
2599 { dnssec = DS_NO; lookup_dnssec_authenticated = US"no"; }
2602 if (temp_fully_qualified_name != g->s && fully_qualified_name != NULL)
2603 *fully_qualified_name = temp_fully_qualified_name + prefix_length;
2605 /* On DNS failures, we give the "try again" error unless the domain is
2606 listed as one for which we continue. */
2608 if (rc == DNS_SUCCEED && dnssec_require && !dns_is_secure(&dnsa))
2610 log_write(L_host_lookup_failed, LOG_MAIN,
2611 "dnssec fail on SRV for %.256s", host->name);
2614 if (rc == DNS_FAIL || rc == DNS_AGAIN)
2617 if (match_isinlist(host->name, CUSS &srv_fail_domains, 0, NULL, NULL,
2618 MCL_DOMAIN, TRUE, NULL) != OK)
2620 { yield = HOST_FIND_AGAIN; goto out; }
2621 DEBUG(D_host_lookup) debug_printf("DNS_%s treated as DNS_NODATA "
2622 "(domain in srv_fail_domains)\n", (rc == DNS_FAIL)? "FAIL":"AGAIN");
2626 /* If we did not find any SRV records, search the DNS for MX records, if
2627 requested to do so. If the result is DNS_NOMATCH, it means there is no such
2628 domain, and there's no point in going on to look for address records with the
2629 same domain. The result will be DNS_NODATA if the domain exists but has no MX
2630 records. On DNS failures, we give the "try again" error unless the domain is
2631 listed as one for which we continue. */
2633 if (rc != DNS_SUCCEED && whichrrs & HOST_FIND_BY_MX)
2637 lookup_dnssec_authenticated = NULL;
2638 rc = dns_lookup_timerwrap(&dnsa, host->name, ind_type, fully_qualified_name);
2641 if ( (dnssec_request || dnssec_require)
2642 && !dns_is_secure(&dnsa)
2643 && dns_is_aa(&dnsa))
2644 debug_printf("DNS lookup of %.256s (MX) requested AD, but got AA\n", host->name);
2647 if (dns_is_secure(&dnsa))
2649 DEBUG(D_host_lookup) debug_printf("%s MX DNSSEC\n", host->name);
2650 dnssec = DS_YES; lookup_dnssec_authenticated = US"yes";
2654 dnssec = DS_NO; lookup_dnssec_authenticated = US"no";
2660 yield = HOST_FIND_FAILED; goto out;
2663 if (!dnssec_require || dns_is_secure(&dnsa))
2665 DEBUG(D_host_lookup)
2666 debug_printf("dnssec fail on MX for %.256s", host->name);
2668 if (match_isinlist(host->name, CUSS &mx_fail_domains, 0, NULL, NULL,
2669 MCL_DOMAIN, TRUE, NULL) != OK)
2670 { yield = HOST_FIND_SECURITY; goto out; }
2678 if (match_isinlist(host->name, CUSS &mx_fail_domains, 0, NULL, NULL,
2679 MCL_DOMAIN, TRUE, NULL) != OK)
2681 { yield = HOST_FIND_AGAIN; goto out; }
2682 DEBUG(D_host_lookup) debug_printf("DNS_%s treated as DNS_NODATA "
2683 "(domain in mx_fail_domains)\n", (rc == DNS_FAIL)? "FAIL":"AGAIN");
2688 /* If we haven't found anything yet, and we are requested to do so, try for an
2689 A or AAAA record. If we find it (or them) check to see that it isn't the local
2692 if (rc != DNS_SUCCEED)
2694 if (!(whichrrs & (HOST_FIND_BY_A | HOST_FIND_BY_AAAA)))
2696 DEBUG(D_host_lookup) debug_printf("Address records are not being sought\n");
2697 yield = HOST_FIND_FAILED;
2701 last = host; /* End of local chainlet */
2703 host->port = PORT_NONE;
2704 host->dnssec = DS_UNK;
2705 lookup_dnssec_authenticated = NULL;
2706 rc = set_address_from_dns(host, &last, ignore_target_hosts, FALSE,
2707 fully_qualified_name, dnssec_request, dnssec_require, whichrrs);
2709 /* If one or more address records have been found, check that none of them
2710 are local. Since we know the host items all have their IP addresses
2711 inserted, host_scan_for_local_hosts() can only return HOST_FOUND or
2712 HOST_FOUND_LOCAL. We do not need to scan for duplicate IP addresses here,
2713 because set_address_from_dns() removes them. */
2715 if (rc == HOST_FOUND)
2716 rc = host_scan_for_local_hosts(host, &last, removed);
2718 if (rc == HOST_IGNORED) rc = HOST_FIND_FAILED; /* No special action */
2720 DEBUG(D_host_lookup)
2723 if (fully_qualified_name)
2724 debug_printf("fully qualified name = %s\n", *fully_qualified_name);
2725 for (host_item * h = host; h != last->next; h = h->next)
2726 debug_printf("%s %s mx=%d sort=%d %s\n", h->name,
2727 h->address ? h->address : US"<null>", h->mx, h->sort_key,
2728 h->status >= hstatus_unusable ? US"*" : US"");
2735 /* We have found one or more MX or SRV records. Sort them according to
2736 precedence. Put the data for the first one into the existing host block, and
2737 insert new host_item blocks into the chain for the remainder. For equal
2738 precedences one is supposed to randomize the order. To make this happen, the
2739 sorting is actually done on the MX value * 1000 + a random number. This is put
2740 into a host field called sort_key.
2742 In the case of hosts with both IPv6 and IPv4 addresses, we want to choose the
2743 IPv6 address in preference. At this stage, we don't know what kind of address
2744 the host has. We choose a random number < 500; if later we find an A record
2745 first, we add 500 to the random number. Then for any other address records, we
2746 use random numbers in the range 0-499 for AAAA records and 500-999 for A
2749 At this point we remove any duplicates that point to the same host, retaining
2750 only the one with the lowest precedence. We cannot yet check for precedence
2751 greater than that of the local host, because that test cannot be properly done
2752 until the addresses have been found - an MX record may point to a name for this
2753 host which is not the primary hostname. */
2755 last = NULL; /* Indicates that not even the first item is filled yet */
2757 for (dns_record * rr = dns_next_rr(&dnsa, &dnss, RESET_ANSWERS);
2759 rr = dns_next_rr(&dnsa, &dnss, RESET_NEXT)) if (rr->type == ind_type)
2761 int precedence, weight;
2762 int port = PORT_NONE;
2763 const uschar * s = rr->data; /* MUST be unsigned for GETSHORT */
2766 GETSHORT(precedence, s); /* Pointer s is advanced */
2768 /* For MX records, we use a random "weight" which causes multiple records of
2769 the same precedence to sort randomly. */
2771 if (ind_type == T_MX)
2772 weight = random_number(500);
2775 /* SRV records are specified with a port and a weight. The weight is used
2776 in a special algorithm. However, to start with, we just use it to order the
2777 records of equal priority (precedence). */
2778 GETSHORT(weight, s);
2782 /* Get the name of the host pointed to. */
2784 (void)dn_expand(dnsa.answer, dnsa.answer + dnsa.answerlen, s,
2785 (DN_EXPAND_ARG4_TYPE)data, sizeof(data));
2787 /* Check that we haven't already got this host on the chain; if we have,
2788 keep only the lower precedence. This situation shouldn't occur, but you
2789 never know what junk might get into the DNS (and this case has been seen on
2790 more than one occasion). */
2792 if (last) /* This is not the first record */
2794 host_item *prev = NULL;
2796 for (h = host; h != last->next; prev = h, h = h->next)
2797 if (strcmpic(h->name, data) == 0)
2799 DEBUG(D_host_lookup)
2800 debug_printf("discarded duplicate host %s (MX=%d)\n", data,
2801 precedence > h->mx ? precedence : h->mx);
2802 if (precedence >= h->mx) goto NEXT_MX_RR; /* Skip greater precedence */
2803 if (h == host) /* Override first item */
2806 host->sort_key = precedence * 1000 + weight;
2810 /* Unwanted host item is not the first in the chain, so we can get
2811 get rid of it by cutting it out. */
2813 prev->next = h->next;
2814 if (h == last) last = prev;
2819 /* If this is the first MX or SRV record, put the data into the existing host
2820 block. Otherwise, add a new block in the correct place; if it has to be
2821 before the first block, copy the first block's data to a new second block. */
2825 host->name = string_copy_dnsdomain(data);
2826 host->address = NULL;
2828 host->mx = precedence;
2829 host->sort_key = precedence * 1000 + weight;
2830 host->status = hstatus_unknown;
2831 host->why = hwhy_unknown;
2832 host->dnssec = dnssec;
2837 /* Make a new host item and seek the correct insertion place */
2839 int sort_key = precedence * 1000 + weight;
2840 host_item *next = store_get(sizeof(host_item));
2841 next->name = string_copy_dnsdomain(data);
2842 next->address = NULL;
2844 next->mx = precedence;
2845 next->sort_key = sort_key;
2846 next->status = hstatus_unknown;
2847 next->why = hwhy_unknown;
2848 next->dnssec = dnssec;
2851 /* Handle the case when we have to insert before the first item. */
2853 if (sort_key < host->sort_key)
2860 if (last == host) last = next;
2864 /* Else scan down the items we have inserted as part of this exercise;
2865 don't go further. */
2867 for (h = host; h != last; h = h->next)
2868 if (sort_key < h->next->sort_key)
2870 next->next = h->next;
2875 /* Join on after the last host item that's part of this
2876 processing if we haven't stopped sooner. */
2880 next->next = last->next;
2887 NEXT_MX_RR: continue;
2890 if (!last) /* No rr of correct type; give up */
2892 yield = HOST_FIND_FAILED;
2896 /* If the list of hosts was obtained from SRV records, there are two things to
2897 do. First, if there is only one host, and it's name is ".", it means there is
2898 no SMTP service at this domain. Otherwise, we have to sort the hosts of equal
2899 priority according to their weights, using an algorithm that is defined in RFC
2900 2782. The hosts are currently sorted by priority and weight. For each priority
2901 group we have to pick off one host and put it first, and then repeat for any
2902 remaining in the same priority group. */
2904 if (ind_type == T_SRV)
2908 if (host == last && host->name[0] == 0)
2910 DEBUG(D_host_lookup) debug_printf("the single SRV record is \".\"\n");
2911 yield = HOST_FIND_FAILED;
2915 DEBUG(D_host_lookup)
2917 debug_printf("original ordering of hosts from SRV records:\n");
2918 for (h = host; h != last->next; h = h->next)
2919 debug_printf(" %s P=%d W=%d\n", h->name, h->mx, h->sort_key % 1000);
2922 for (pptr = &host, h = host; h != last; pptr = &h->next, h = h->next)
2927 /* Find the last following host that has the same precedence. At the same
2928 time, compute the sum of the weights and the running totals. These can be
2929 stored in the sort_key field. */
2931 for (hh = h; hh != last; hh = hh->next)
2933 int weight = hh->sort_key % 1000; /* was precedence * 1000 + weight */
2936 if (hh->mx != hh->next->mx) break;
2939 /* If there's more than one host at this precedence (priority), we need to
2940 pick one to go first. */
2946 int randomizer = random_number(sum + 1);
2948 for (ppptr = pptr, hhh = h;
2950 ppptr = &hhh->next, hhh = hhh->next)
2951 if (hhh->sort_key >= randomizer)
2954 /* hhh now points to the host that should go first; ppptr points to the
2955 place that points to it. Unfortunately, if the start of the minilist is
2956 the start of the entire list, we can't just swap the items over, because
2957 we must not change the value of host, since it is passed in from outside.
2958 One day, this could perhaps be changed.
2960 The special case is fudged by putting the new item *second* in the chain,
2961 and then transferring the data between the first and second items. We
2962 can't just swap the first and the chosen item, because that would mean
2963 that an item with zero weight might no longer be first. */
2967 *ppptr = hhh->next; /* Cuts it out of the chain */
2971 host_item temp = *h;
2974 hhh->next = temp.next;
2979 hhh->next = h; /* The rest of the chain follows it */
2980 *pptr = hhh; /* It takes the place of h */
2981 h = hhh; /* It's now the start of this minilist */
2986 /* A host has been chosen to be first at this priority and h now points
2987 to this host. There may be others at the same priority, or others at a
2988 different priority. Before we leave this host, we need to put back a sort
2989 key of the traditional MX kind, in case this host is multihomed, because
2990 the sort key is used for ordering the multiple IP addresses. We do not need
2991 to ensure that these new sort keys actually reflect the order of the hosts,
2994 h->sort_key = h->mx * 1000 + random_number(500);
2995 } /* Move on to the next host */
2998 /* Now we have to find IP addresses for all the hosts. We have ensured above
2999 that the names in all the host items are unique. Before release 4.61 we used to
3000 process records from the additional section in the DNS packet that returned the
3001 MX or SRV records. However, a DNS name server is free to drop any resource
3002 records from the additional section. In theory, this has always been a
3003 potential problem, but it is exacerbated by the advent of IPv6. If a host had
3004 several IPv4 addresses and some were not in the additional section, at least
3005 Exim would try the others. However, if a host had both IPv4 and IPv6 addresses
3006 and all the IPv4 (say) addresses were absent, Exim would try only for a IPv6
3007 connection, and never try an IPv4 address. When there was only IPv4
3008 connectivity, this was a disaster that did in practice occur.
3010 So, from release 4.61 onwards, we always search for A and AAAA records
3011 explicitly. The names shouldn't point to CNAMES, but we use the general lookup
3012 function that handles them, just in case. If any lookup gives a soft error,
3013 change the default yield.
3015 For these DNS lookups, we must disable qualify_single and search_parents;
3016 otherwise invalid host names obtained from MX or SRV records can cause trouble
3017 if they happen to match something local. */
3019 yield = HOST_FIND_FAILED; /* Default yield */
3020 dns_init(FALSE, FALSE, /* Disable qualify_single and search_parents */
3021 dnssec_request || dnssec_require);
3023 for (h = host; h != last->next; h = h->next)
3025 if (h->address) continue; /* Inserted by a multihomed host */
3027 rc = set_address_from_dns(h, &last, ignore_target_hosts, allow_mx_to_ip,
3028 NULL, dnssec_request, dnssec_require,
3029 whichrrs & HOST_FIND_IPV4_ONLY
3030 ? HOST_FIND_BY_A : HOST_FIND_BY_A | HOST_FIND_BY_AAAA);
3031 if (rc != HOST_FOUND)
3033 h->status = hstatus_unusable;
3036 case HOST_FIND_AGAIN: yield = rc; h->why = hwhy_deferred; break;
3037 case HOST_FIND_SECURITY: yield = rc; h->why = hwhy_insecure; break;
3038 case HOST_IGNORED: h->why = hwhy_ignored; break;
3039 default: h->why = hwhy_failed; break;
3044 /* Scan the list for any hosts that are marked unusable because they have
3045 been explicitly ignored, and remove them from the list, as if they did not
3046 exist. If we end up with just a single, ignored host, flatten its fields as if
3047 nothing was found. */
3049 if (ignore_target_hosts)
3051 host_item *prev = NULL;
3052 for (h = host; h != last->next; h = h->next)
3055 if (h->why != hwhy_ignored) /* Non ignored host, just continue */
3057 else if (prev == NULL) /* First host is ignored */
3059 if (h != last) /* First is not last */
3061 if (h->next == last) last = h; /* Overwrite it with next */
3062 *h = *(h->next); /* and reprocess it. */
3063 goto REDO; /* C should have redo, like Perl */
3066 else /* Ignored host is not first - */
3068 prev->next = h->next;
3069 if (h == last) last = prev;
3073 if (host->why == hwhy_ignored) host->address = NULL;
3076 /* There is still one complication in the case of IPv6. Although the code above
3077 arranges that IPv6 addresses take precedence over IPv4 addresses for multihomed
3078 hosts, it doesn't do this for addresses that apply to different hosts with the
3079 same MX precedence, because the sorting on MX precedence happens first. So we
3080 have to make another pass to check for this case. We ensure that, within a
3081 single MX preference value, IPv6 addresses come first. This can separate the
3082 addresses of a multihomed host, but that should not matter. */
3085 if (h != last && !disable_ipv6) for (h = host; h != last; h = h->next)
3088 host_item *next = h->next;
3090 if ( h->mx != next->mx /* If next is different MX */
3091 || !h->address /* OR this one is unset */
3093 continue; /* move on to next */
3095 if ( whichrrs & HOST_FIND_IPV4_FIRST
3096 ? !Ustrchr(h->address, ':') /* OR this one is IPv4 */
3098 && Ustrchr(next->address, ':') /* OR next is IPv6 */
3100 : Ustrchr(h->address, ':') /* OR this one is IPv6 */
3102 && !Ustrchr(next->address, ':') /* OR next is IPv4 */
3104 continue; /* move on to next */
3106 temp = *h; /* otherwise, swap */
3107 temp.next = next->next;
3114 /* Remove any duplicate IP addresses and then scan the list of hosts for any
3115 whose IP addresses are on the local host. If any are found, all hosts with the
3116 same or higher MX values are removed. However, if the local host has the lowest
3117 numbered MX, then HOST_FOUND_LOCAL is returned. Otherwise, if at least one host
3118 with an IP address is on the list, HOST_FOUND is returned. Otherwise,
3119 HOST_FIND_FAILED is returned, but in this case do not update the yield, as it
3120 might have been set to HOST_FIND_AGAIN just above here. If not, it will already
3121 be HOST_FIND_FAILED. */
3123 host_remove_duplicates(host, &last);
3124 rc = host_scan_for_local_hosts(host, &last, removed);
3125 if (rc != HOST_FIND_FAILED) yield = rc;
3127 DEBUG(D_host_lookup)
3129 if (fully_qualified_name)
3130 debug_printf("fully qualified name = %s\n", *fully_qualified_name);
3131 debug_printf("host_find_bydns yield = %s (%d); returned hosts:\n",
3132 yield == HOST_FOUND ? "HOST_FOUND" :
3133 yield == HOST_FOUND_LOCAL ? "HOST_FOUND_LOCAL" :
3134 yield == HOST_FIND_SECURITY ? "HOST_FIND_SECURITY" :
3135 yield == HOST_FIND_AGAIN ? "HOST_FIND_AGAIN" :
3136 yield == HOST_FIND_FAILED ? "HOST_FIND_FAILED" : "?",
3138 for (h = host; h != last->next; h = h->next)
3140 debug_printf(" %s %s MX=%d %s", h->name,
3141 !h->address ? US"<null>" : h->address, h->mx,
3142 h->dnssec == DS_YES ? US"DNSSEC " : US"");
3143 if (h->port != PORT_NONE) debug_printf("port=%d ", h->port);
3144 if (h->status >= hstatus_unusable) debug_printf("*");
3151 dns_init(FALSE, FALSE, FALSE); /* clear the dnssec bit for getaddrbyname */
3155 /*************************************************
3156 **************************************************
3157 * Stand-alone test program *
3158 **************************************************
3159 *************************************************/
3163 int main(int argc, char **cargv)
3166 int whichrrs = HOST_FIND_BY_MX | HOST_FIND_BY_A | HOST_FIND_BY_AAAA;
3167 BOOL byname = FALSE;
3168 BOOL qualify_single = TRUE;
3169 BOOL search_parents = FALSE;
3170 BOOL request_dnssec = FALSE;
3171 BOOL require_dnssec = FALSE;
3172 uschar **argv = USS cargv;
3175 disable_ipv6 = FALSE;
3176 primary_hostname = US"";
3177 store_pool = POOL_MAIN;
3178 debug_selector = D_host_lookup|D_interface;
3179 debug_file = stdout;
3180 debug_fd = fileno(debug_file);
3182 printf("Exim stand-alone host functions test\n");
3184 host_find_interfaces();
3185 debug_selector = D_host_lookup | D_dns;
3187 if (argc > 1) primary_hostname = argv[1];
3189 /* So that debug level changes can be done first */
3191 dns_init(qualify_single, search_parents, FALSE);
3193 printf("Testing host lookup\n");
3195 while (Ufgets(buffer, 256, stdin) != NULL)
3198 int len = Ustrlen(buffer);
3199 uschar *fully_qualified_name;
3201 while (len > 0 && isspace(buffer[len-1])) len--;
3204 if (Ustrcmp(buffer, "q") == 0) break;
3206 if (Ustrcmp(buffer, "byname") == 0) byname = TRUE;
3207 else if (Ustrcmp(buffer, "no_byname") == 0) byname = FALSE;
3208 else if (Ustrcmp(buffer, "a_only") == 0) whichrrs = HOST_FIND_BY_A | HOST_FIND_BY_AAAA;
3209 else if (Ustrcmp(buffer, "mx_only") == 0) whichrrs = HOST_FIND_BY_MX;
3210 else if (Ustrcmp(buffer, "srv_only") == 0) whichrrs = HOST_FIND_BY_SRV;
3211 else if (Ustrcmp(buffer, "srv+a") == 0)
3212 whichrrs = HOST_FIND_BY_SRV | HOST_FIND_BY_A | HOST_FIND_BY_AAAA;
3213 else if (Ustrcmp(buffer, "srv+mx") == 0)
3214 whichrrs = HOST_FIND_BY_SRV | HOST_FIND_BY_MX;
3215 else if (Ustrcmp(buffer, "srv+mx+a") == 0)
3216 whichrrs = HOST_FIND_BY_SRV | HOST_FIND_BY_MX | HOST_FIND_BY_A | HOST_FIND_BY_AAAA;
3217 else if (Ustrcmp(buffer, "qualify_single") == 0) qualify_single = TRUE;
3218 else if (Ustrcmp(buffer, "no_qualify_single") == 0) qualify_single = FALSE;
3219 else if (Ustrcmp(buffer, "search_parents") == 0) search_parents = TRUE;
3220 else if (Ustrcmp(buffer, "no_search_parents") == 0) search_parents = FALSE;
3221 else if (Ustrcmp(buffer, "request_dnssec") == 0) request_dnssec = TRUE;
3222 else if (Ustrcmp(buffer, "no_request_dnssec") == 0) request_dnssec = FALSE;
3223 else if (Ustrcmp(buffer, "require_dnssec") == 0) require_dnssec = TRUE;
3224 else if (Ustrcmp(buffer, "no_require_dnssec") == 0) require_dnssec = FALSE;
3225 else if (Ustrcmp(buffer, "test_harness") == 0)
3226 f.running_in_test_harness = !f.running_in_test_harness;
3227 else if (Ustrcmp(buffer, "ipv6") == 0) disable_ipv6 = !disable_ipv6;
3228 else if (Ustrcmp(buffer, "res_debug") == 0)
3230 _res.options ^= RES_DEBUG;
3232 else if (Ustrncmp(buffer, "retrans", 7) == 0)
3234 (void)sscanf(CS(buffer+8), "%d", &dns_retrans);
3235 _res.retrans = dns_retrans;
3237 else if (Ustrncmp(buffer, "retry", 5) == 0)
3239 (void)sscanf(CS(buffer+6), "%d", &dns_retry);
3240 _res.retry = dns_retry;
3244 int flags = whichrrs;
3251 h.status = hstatus_unknown;
3252 h.why = hwhy_unknown;
3255 if (qualify_single) flags |= HOST_FIND_QUALIFY_SINGLE;
3256 if (search_parents) flags |= HOST_FIND_SEARCH_PARENTS;
3258 d.request = request_dnssec ? &h.name : NULL;
3259 d.require = require_dnssec ? &h.name : NULL;
3262 ? host_find_byname(&h, NULL, flags, &fully_qualified_name, TRUE)
3263 : host_find_bydns(&h, NULL, flags, US"smtp", NULL, NULL,
3264 &d, &fully_qualified_name, NULL);
3268 case HOST_FIND_FAILED: printf("Failed\n"); break;
3269 case HOST_FIND_AGAIN: printf("Again\n"); break;
3270 case HOST_FIND_SECURITY: printf("Security\n"); break;
3271 case HOST_FOUND_LOCAL: printf("Local\n"); break;
3278 printf("Testing host_aton\n");
3280 while (Ufgets(buffer, 256, stdin) != NULL)
3283 int len = Ustrlen(buffer);
3285 while (len > 0 && isspace(buffer[len-1])) len--;
3288 if (Ustrcmp(buffer, "q") == 0) break;
3290 len = host_aton(buffer, x);
3291 printf("length = %d ", len);
3292 for (int i = 0; i < len; i++)
3294 printf("%04x ", (x[i] >> 16) & 0xffff);
3295 printf("%04x ", x[i] & 0xffff);
3302 printf("Testing host_name_lookup\n");
3304 while (Ufgets(buffer, 256, stdin) != NULL)
3306 int len = Ustrlen(buffer);
3307 while (len > 0 && isspace(buffer[len-1])) len--;
3309 if (Ustrcmp(buffer, "q") == 0) break;
3310 sender_host_address = buffer;
3311 sender_host_name = NULL;
3312 sender_host_aliases = NULL;
3313 host_lookup_msg = US"";
3314 host_lookup_failed = FALSE;
3315 if (host_name_lookup() == FAIL) /* Debug causes printing */
3316 printf("Lookup failed:%s\n", host_lookup_msg);
3324 #endif /* STAND_ALONE */