-/* $Cambridge: exim/src/src/dns.c,v 1.14 2006/02/16 10:05:33 ph10 Exp $ */
+/* $Cambridge: exim/src/src/dns.c,v 1.17 2007/01/08 10:50:18 ph10 Exp $ */
/*************************************************
* Exim - an Internet mail transport agent *
*************************************************/
-/* Copyright (c) University of Cambridge 1995 - 2006 */
+/* Copyright (c) University of Cambridge 1995 - 2007 */
/* See the file NOTICE for conditions of use and distribution. */
/* Functions for interfacing with the DNS. */
Returns: DNS_SUCCEED successful lookup
DNS_NOMATCH name not found (NXDOMAIN)
or name contains illegal characters (if checking)
+ or name is an IP address (for IP address lookup)
DNS_NODATA domain exists, but no data for this type (NODATA)
DNS_AGAIN soft failure, try again later
DNS_FAIL DNS failure
number of bytes the message would need, so we need to check for this case. The
effect is to truncate overlong data.
-If we are running in the test harness, instead of calling the normal resolver
+On some systems, res_search() will recognize "A-for-A" queries and return
+the IP address instead of returning -1 with h_error=HOST_NOT_FOUND. Some
+nameservers are also believed to do this. It is, of course, contrary to the
+specification of the DNS, so we lock it out. */
+
+if ((
+ #ifdef SUPPORT_A6
+ type == T_A6 ||
+ #endif
+ type == T_A || type == T_AAAA) &&
+ string_is_ip_address(name, NULL) != 0)
+ return DNS_NOMATCH;
+
+/* If we are running in the test harness, instead of calling the normal resolver
(res_search), we call fakens_search(), which recognizes certain special
domains, and interfaces to a fake nameserver for certain special zones. */
else if (rr->type == T_CNAME) cname_rr = *rr;
}
- /* If a CNAME was found, take the fully qualified name from it; otherwise
- from the first data record, if present. For testing, there is a magic name
- that gets its casing adjusted, because my resolver doesn't seem to pass back
- upper case letters in domain names. */
+ /* For the first time round this loop, if a CNAME was found, take the fully
+ qualified name from it; otherwise from the first data record, if present. */
- if (fully_qualified_name != NULL)
+ if (i == 0 && fully_qualified_name != NULL)
{
if (cname_rr.data != NULL)
{
cname_rr.data, (DN_EXPAND_ARG4_TYPE)data, 256);
if (datalen < 0) return DNS_FAIL;
name = data;
+
+ DEBUG(D_dns) debug_printf("CNAME found: change to %s\n", name);
} /* Loop back to do another lookup */
/*Control reaches here after 10 times round the CNAME loop. Something isn't