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Resolve chained CNAME records

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svn path=/trunk/; revision=20082
This commit is contained in:
Gé van Geldorp 2005-12-11 21:17:58 +00:00
parent fc95df91f3
commit 0c0ecd45ea
1 changed files with 77 additions and 26 deletions
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103
reactos/lib/dnsapi/dnsapi/query.c
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@ -34,8 +34,10 @@
char *xstrsave(const char *str) {
char *p;
p= RtlAllocateHeap( RtlGetProcessHeap(), 0, strlen(str)+1 );
strcpy(p,str);
p = RtlAllocateHeap( RtlGetProcessHeap(), 0, strlen(str)+1 );
if ( NULL != p ) {
strcpy(p,str);
}
return p;
}
@ -50,6 +52,8 @@ DNS_STATUS WINAPI DnsQuery_A
int quflags = 0;
int adns_error;
adns_answer *answer;
LPSTR CurrentName;
unsigned CNameLoop;
*QueryResultSet = 0;
@ -64,31 +68,78 @@ DNS_STATUS WINAPI DnsQuery_A
return DnsIntTranslateAdnsToDNS_STATUS( adns_error );
}
adns_error = adns_synchronous( astate,
Name,
adns_r_addr,
quflags,
&answer );
if( adns_error != adns_s_ok ) {
adns_finish( astate );
return DnsIntTranslateAdnsToDNS_STATUS( adns_error );
}
/*
* adns doesn't resolve chained CNAME records (a CNAME which points to
* another CNAME pointing to another... pointing to an A record), according
* to a mailing list thread the authors believe that chained CNAME records
* are invalid and the DNS entries should be fixed. That's a nice academic
* standpoint, but there certainly are chained CNAME records out there,
* even some fairly major ones (at the time of this writing
* download.mozilla.org is a chained CNAME). Everyone else seems to resolve
* these fine, so we should too. So we loop here to try to resolve CNAME
* chains ourselves. Of course, there must be a limit to protect against
* CNAME loops.
*/
if( answer && answer->rrs.addr ) {
*QueryResultSet =
(PDNS_RECORD)RtlAllocateHeap( RtlGetProcessHeap(), 0,
sizeof( DNS_RECORD ) );
(*QueryResultSet)->pNext = NULL;
(*QueryResultSet)->wType = Type;
(*QueryResultSet)->pName = xstrsave( Name );
(*QueryResultSet)->wDataLength = sizeof(DNS_A_DATA);
(*QueryResultSet)->Data.A.IpAddress =
answer->rrs.addr->addr.inet.sin_addr.s_addr;
adns_finish( astate );
return ERROR_SUCCESS;
} else
return ERROR_FILE_NOT_FOUND;
#define CNAME_LOOP_MAX 16
CurrentName = (LPSTR) Name;
for ( CNameLoop = 0; CNameLoop < CNAME_LOOP_MAX; CNameLoop++ ) {
adns_error = adns_synchronous( astate,
CurrentName,
adns_r_addr,
quflags,
&answer );
if( adns_error != adns_s_ok ) {
adns_finish( astate );
if ( CurrentName != Name ) {
RtlFreeHeap( CurrentName, 0, GetProcessHeap() );
}
return DnsIntTranslateAdnsToDNS_STATUS( adns_error );
}
if( answer && answer->rrs.addr ) {
if ( CurrentName != Name ) {
RtlFreeHeap( CurrentName, 0, GetProcessHeap() );
}
*QueryResultSet =
(PDNS_RECORD)RtlAllocateHeap( RtlGetProcessHeap(), 0,
sizeof( DNS_RECORD ) );
if ( NULL == *QueryResultSet ) {
adns_finish( astate );
return ERROR_OUTOFMEMORY;
}
(*QueryResultSet)->pNext = NULL;
(*QueryResultSet)->wType = Type;
(*QueryResultSet)->wDataLength = sizeof(DNS_A_DATA);
(*QueryResultSet)->Data.A.IpAddress =
answer->rrs.addr->addr.inet.sin_addr.s_addr;
adns_finish( astate );
(*QueryResultSet)->pName = xstrsave( Name );
return NULL != (*QueryResultSet)->pName ? ERROR_SUCCESS :
ERROR_OUTOFMEMORY;
}
if ( NULL == answer || adns_s_prohibitedcname != answer->status ||
NULL == answer->cname ) {
adns_finish( astate );
if ( CurrentName != Name ) {
RtlFreeHeap( CurrentName, 0, GetProcessHeap() );
}
return ERROR_FILE_NOT_FOUND;
}
if ( CurrentName != Name ) {
RtlFreeHeap( CurrentName, 0, GetProcessHeap() );
}
CurrentName = xstrsave( answer->cname );
if ( NULL == CurrentName ) {
adns_finish( astate );
return ERROR_OUTOFMEMORY;
}
}
adns_finish( astate );
RtlFreeHeap( CurrentName, 0, GetProcessHeap() );
return ERROR_FILE_NOT_FOUND;
default:
return ERROR_OUTOFMEMORY; /* XXX arty: find a better error code. */
}