* Exim - an Internet mail transport agent *
*************************************************/
-/* Copyright (c) University of Cambridge 1995 - 2016 */
+/* Copyright (c) University of Cambridge 1995 - 2017 */
/* See the file NOTICE for conditions of use and distribution. */
/* Functions for finding hosts, either by gethostbyname(), gethostbyaddr(), or
d.request = sender_host_dnssec ? US"*" : NULL;;
d.require = NULL;
- if ( (rc = host_find_bydns(&h, NULL, HOST_FIND_BY_A,
+ if ( (rc = host_find_bydns(&h, NULL, HOST_FIND_BY_A | HOST_FIND_BY_AAAA,
NULL, NULL, NULL, &d, NULL, NULL)) == HOST_FOUND
|| rc == HOST_FOUND_LOCAL
)
create additional host items for the additional addresses, copying all the
other fields, and randomizing the order.
-On IPv6 systems, A6 records are sought first (but only if support for A6 is
-configured - they may never become mainstream), then AAAA records are sought,
-and finally A records are sought as well.
+On IPv6 systems, AAAA records are sought first, then A records.
The host name may be changed if the DNS returns a different name - e.g. fully
qualified or changed via CNAME. If fully_qualified_name is not NULL, dns_lookup
to something)
dnssec_request if TRUE request the AD bit
dnssec_require if TRUE require the AD bit
+ whichrrs select ipv4, ipv6 results
Returns: HOST_FIND_FAILED couldn't find A record
HOST_FIND_AGAIN try again later
set_address_from_dns(host_item *host, host_item **lastptr,
const uschar *ignore_target_hosts, BOOL allow_ip,
const uschar **fully_qualified_name,
- BOOL dnssec_request, BOOL dnssec_require)
+ BOOL dnssec_request, BOOL dnssec_require, int whichrrs)
{
dns_record *rr;
host_item *thishostlast = NULL; /* Indicates not yet filled in anything */
if (allow_ip && string_is_ip_address(host->name, NULL) != 0)
{
#ifndef STAND_ALONE
- if (ignore_target_hosts != NULL &&
- verify_check_this_host(&ignore_target_hosts, NULL, host->name,
+ if ( ignore_target_hosts
+ && verify_check_this_host(&ignore_target_hosts, NULL, host->name,
host->name, NULL) == OK)
return HOST_IGNORED;
#endif
}
/* On an IPv6 system, unless IPv6 is disabled, go round the loop up to twice,
-looking for AAAA records the first time. However, unless
-doing standalone testing, we force an IPv4 lookup if the domain matches
-dns_ipv4_lookup is set. On an IPv4 system, go round the
-loop once only, looking only for A records. */
+looking for AAAA records the first time. However, unless doing standalone
+testing, we force an IPv4 lookup if the domain matches dns_ipv4_lookup global.
+On an IPv4 system, go round the loop once only, looking only for A records. */
#if HAVE_IPV6
#ifndef STAND_ALONE
- if (disable_ipv6 || (dns_ipv4_lookup != NULL &&
- match_isinlist(host->name, CUSS &dns_ipv4_lookup, 0, NULL, NULL,
- MCL_DOMAIN, TRUE, NULL) == OK))
+ if ( disable_ipv6
+ || !(whichrrs & HOST_FIND_BY_AAAA)
+ || (dns_ipv4_lookup
+ && match_isinlist(host->name, CUSS &dns_ipv4_lookup, 0, NULL, NULL,
+ MCL_DOMAIN, TRUE, NULL) == OK)
+ )
i = 0; /* look up A records only */
else
#endif /* STAND_ALONE */
{
static int types[] = { T_A, T_AAAA };
int type = types[i];
- int randoffset = (i == 0)? 500 : 0; /* Ensures v6 sorts before v4 */
+ int randoffset = i == (whichrrs & HOST_FIND_IPV4_FIRST ? 1 : 0)
+ ? 500 : 0; /* Ensures v6/4 sort order */
dns_answer dnsa;
dns_scan dnss;
whichrrs flags indicating which RRs to look for:
HOST_FIND_BY_SRV => look for SRV
HOST_FIND_BY_MX => look for MX
- HOST_FIND_BY_A => look for A or AAAA
+ HOST_FIND_BY_A => look for A
+ HOST_FIND_BY_AAAA => look for AAAA
also flags indicating how the lookup is done
HOST_FIND_QUALIFY_SINGLE ) passed to the
HOST_FIND_SEARCH_PARENTS ) resolver
+ HOST_FIND_IPV4_FIRST => reverse usual result ordering
+ HOST_FIND_IPV4_ONLY => MX results elide ipv6
srv_service when SRV used, the service name
srv_fail_domains DNS errors for these domains => assume nonexist
mx_fail_domains DNS errors for these domains => assume nonexist
DEBUG(D_dns)
if ((dnssec_request || dnssec_require)
- & !dns_is_secure(&dnsa)
- & dns_is_aa(&dnsa))
+ && !dns_is_secure(&dnsa)
+ && dns_is_aa(&dnsa))
debug_printf("DNS lookup of %.256s (SRV) requested AD, but got AA\n", host->name);
if (dnssec_request)
if (rc != DNS_SUCCEED)
{
- if ((whichrrs & HOST_FIND_BY_A) == 0)
+ if (!(whichrrs & (HOST_FIND_BY_A | HOST_FIND_BY_AAAA)))
{
DEBUG(D_host_lookup) debug_printf("Address records are not being sought\n");
yield = HOST_FIND_FAILED;
host->dnssec = DS_UNK;
lookup_dnssec_authenticated = NULL;
rc = set_address_from_dns(host, &last, ignore_target_hosts, FALSE,
- fully_qualified_name, dnssec_request, dnssec_require);
+ fully_qualified_name, dnssec_request, dnssec_require, whichrrs);
/* If one or more address records have been found, check that none of them
are local. Since we know the host items all have their IP addresses
if (h->address) continue; /* Inserted by a multihomed host */
rc = set_address_from_dns(h, &last, ignore_target_hosts, allow_mx_to_ip,
- NULL, dnssec_request, dnssec_require);
+ NULL, dnssec_request, dnssec_require,
+ whichrrs & HOST_FIND_IPV4_ONLY
+ ? HOST_FIND_BY_A : HOST_FIND_BY_A | HOST_FIND_BY_AAAA);
if (rc != HOST_FOUND)
{
h->status = hstatus_unusable;
switch (rc)
{
- case HOST_FIND_AGAIN:
- yield = rc; h->why = hwhy_deferred; break;
- case HOST_FIND_SECURITY:
- yield = rc; h->why = hwhy_insecure; break;
- case HOST_IGNORED:
- h->why = hwhy_ignored; break;
- default:
- h->why = hwhy_failed; break;
+ case HOST_FIND_AGAIN: yield = rc; h->why = hwhy_deferred; break;
+ case HOST_FIND_SECURITY: yield = rc; h->why = hwhy_insecure; break;
+ case HOST_IGNORED: h->why = hwhy_ignored; break;
+ default: h->why = hwhy_failed; break;
}
}
}
host_item temp;
host_item *next = h->next;
- if (h->mx != next->mx || /* If next is different MX */
- h->address == NULL || /* OR this one is unset */
- Ustrchr(h->address, ':') != NULL || /* OR this one is IPv6 */
- (next->address != NULL &&
- Ustrchr(next->address, ':') == NULL)) /* OR next is IPv4 */
+ if ( h->mx != next->mx /* If next is different MX */
+ || !h->address /* OR this one is unset */
+ )
+ continue; /* move on to next */
+
+ if ( whichrrs & HOST_FIND_IPV4_FIRST
+ ? !Ustrchr(h->address, ':') /* OR this one is IPv4 */
+ || next->address
+ && Ustrchr(next->address, ':') /* OR next is IPv6 */
+
+ : Ustrchr(h->address, ':') /* OR this one is IPv6 */
+ || next->address
+ && !Ustrchr(next->address, ':') /* OR next is IPv4 */
+ )
continue; /* move on to next */
+
temp = *h; /* otherwise, swap */
temp.next = next->next;
*h = *next;
int main(int argc, char **cargv)
{
host_item h;
-int whichrrs = HOST_FIND_BY_MX | HOST_FIND_BY_A;
+int whichrrs = HOST_FIND_BY_MX | HOST_FIND_BY_A | HOST_FIND_BY_AAAA;
BOOL byname = FALSE;
BOOL qualify_single = TRUE;
BOOL search_parents = FALSE;
if (Ustrcmp(buffer, "byname") == 0) byname = TRUE;
else if (Ustrcmp(buffer, "no_byname") == 0) byname = FALSE;
- else if (Ustrcmp(buffer, "a_only") == 0) whichrrs = HOST_FIND_BY_A;
+ else if (Ustrcmp(buffer, "a_only") == 0) whichrrs = HOST_FIND_BY_A | HOST_FIND_BY_AAAA;
else if (Ustrcmp(buffer, "mx_only") == 0) whichrrs = HOST_FIND_BY_MX;
else if (Ustrcmp(buffer, "srv_only") == 0) whichrrs = HOST_FIND_BY_SRV;
else if (Ustrcmp(buffer, "srv+a") == 0)
- whichrrs = HOST_FIND_BY_SRV | HOST_FIND_BY_A;
+ whichrrs = HOST_FIND_BY_SRV | HOST_FIND_BY_A | HOST_FIND_BY_AAAA;
else if (Ustrcmp(buffer, "srv+mx") == 0)
whichrrs = HOST_FIND_BY_SRV | HOST_FIND_BY_MX;
else if (Ustrcmp(buffer, "srv+mx+a") == 0)
- whichrrs = HOST_FIND_BY_SRV | HOST_FIND_BY_MX | HOST_FIND_BY_A;
+ whichrrs = HOST_FIND_BY_SRV | HOST_FIND_BY_MX | HOST_FIND_BY_A | HOST_FIND_BY_AAAA;
else if (Ustrcmp(buffer, "qualify_single") == 0) qualify_single = TRUE;
else if (Ustrcmp(buffer, "no_qualify_single") == 0) qualify_single = FALSE;
else if (Ustrcmp(buffer, "search_parents") == 0) search_parents = TRUE;
projects / exim.git / blobdiff