-/* $Cambridge: exim/src/src/lookups/dnsdb.c,v 1.5 2004/11/25 14:31:28 ph10 Exp $ */
+/* $Cambridge: exim/src/src/lookups/dnsdb.c,v 1.8 2005/01/04 10:00:44 ph10 Exp $ */
/*************************************************
* Exim - an Internet mail transport agent *
*************************************************/
-/* Copyright (c) University of Cambridge 1995 - 2004 */
+/* Copyright (c) University of Cambridge 1995 - 2005 */
/* See the file NOTICE for conditions of use and distribution. */
#include "../exim.h"
separator character that is used when multiple records are found. The default
separator is newline.
-(b) If the next sequence of characters is a sequence of letters and digits
+(b) If the next sequence of characters is 'defer_FOO' followed by a comma,
+the defer behaviour is set to FOO. The possible behaviours are: 'strict', where
+any defer causes the whole lookup to defer; 'lax', where a defer causes the
+whole lookup to defer only if none of the DNS queries succeeds; and 'never',
+where all defers are as if the lookup failed. The default is 'lax'.
+
+(c) If the next sequence of characters is a sequence of letters and digits
followed by '=', it is interpreted as the name of the DNS record type. The
-default is "A".
+default is "TXT".
-(c) Then there follows list of domain names. This is a generalized Exim list,
+(d) Then there follows list of domain names. This is a generalized Exim list,
which may start with '<' in order to set a specific separator. The default
separator, as always, is colon. */
int size = 256;
int ptr = 0;
int sep = 0;
+int defer_mode = PASS;
int type = T_TXT;
int failrc = FAIL;
uschar *outsep = US"\n";
while (isspace(*keystring)) keystring++;
}
+/* Check for a defer behaviour keyword. */
+
+if (strncmpic(keystring, US"defer_", 6) == 0)
+ {
+ keystring += 6;
+ if (strncmpic(keystring, US"strict", 6) == 0)
+ {
+ defer_mode = DEFER;
+ keystring += 6;
+ }
+ else if (strncmpic(keystring, US"lax", 3) == 0)
+ {
+ defer_mode = PASS;
+ keystring += 3;
+ }
+ else if (strncmpic(keystring, US"never", 5) == 0)
+ {
+ defer_mode = OK;
+ keystring += 5;
+ }
+ else
+ {
+ *errmsg = US"unsupported dnsdb defer behaviour";
+ return DEFER;
+ }
+ while (isspace(*keystring)) keystring++;
+ if (*keystring++ != ',')
+ {
+ *errmsg = US"dnsdb defer behaviour syntax error";
+ return DEFER;
+ }
+ while (isspace(*keystring)) keystring++;
+ }
+
/* If the keystring contains an = this must be preceded by a valid type name. */
if ((equals = Ustrchr(keystring, '=')) != NULL)
int searchtype = (type == T_ZNS)? T_NS : /* record type we want */
(type == T_MXH)? T_MX : type;
- /* If the type is PTR, we have to construct the relevant magic lookup
- key. This code is now in a separate function. */
+ /* If the type is PTR, we have to construct the relevant magic lookup key if
+ the original is an IP address (some experimental protocols are using PTR
+ records for different purposes where the key string is a host name). This
+ code for doing the reversal is now in a separate function. */
- if (type == T_PTR)
+ if (type == T_PTR && string_is_ip_address(domain, NULL))
{
dns_build_reverse(domain, rbuffer);
domain = rbuffer;
if (rc == DNS_NOMATCH || rc == DNS_NODATA) continue;
if (rc != DNS_SUCCEED)
{
- failrc = DEFER;
- continue;
+ if (defer_mode == DEFER) return DEFER; /* always defer */
+ else if (defer_mode == PASS) failrc = DEFER; /* defer only if all do */
+ continue; /* treat defer as fail */
}
/* Search the returned records */