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r17146: Starting to cleanout my local tree some

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* add code to lookup NS records (in prep for later coe that
  does DNS updates as part of the net ads join)
This commit is contained in:
Gerald Carter 2006-07-19 20:53:10 +00:00 committed by Gerald (Jerry) Carter
parent 12490fafc7
commit 36d4970646
2 changed files with 206 additions and 16 deletions
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7
source/include/ads_dns.h
View File

@ -50,5 +50,12 @@ struct dns_rr_srv {
struct in_addr ip;
};
/* SRV records */
struct dns_rr_ns {
const char *hostname;
struct in_addr ip;
};
#endif /* _ADS_DNS_H */

215
source/libads/dns.c
View File

@ -46,6 +46,7 @@
# define T_A ns_t_a
#endif
# define T_SRV ns_t_srv
# define T_NS ns_t_ns
#else
# ifdef HFIXEDSZ
# define NS_HFIXEDSZ HFIXEDSZ
@ -197,6 +198,46 @@ static BOOL ads_dns_parse_rr_srv( TALLOC_CTX *ctx, uint8 *start, uint8 *end,
return True;
}
/*********************************************************************
*********************************************************************/
static BOOL ads_dns_parse_rr_ns( TALLOC_CTX *ctx, uint8 *start, uint8 *end,
uint8 **ptr, struct dns_rr_ns *nsrec )
{
struct dns_rr rr;
uint8 *p;
pstring nsname;
int namelen;
if ( !start || !end || !nsrec || !*ptr)
return -1;
/* Parse the RR entry. Coming out of the this, ptr is at the beginning
of the next record */
if ( !ads_dns_parse_rr( ctx, start, end, ptr, &rr ) ) {
DEBUG(1,("ads_dns_parse_rr_ns: Failed to parse RR record\n"));
return False;
}
if ( rr.type != T_NS ) {
DEBUG(1,("ads_dns_parse_rr_ns: Bad answer type (%d)\n", rr.type));
return False;
}
p = rr.rdata;
/* ame server hostname */
namelen = dn_expand( start, end, p, nsname, sizeof(nsname) );
if ( namelen < 0 ) {
DEBUG(1,("ads_dns_parse_rr_ns: Failed to uncompress name!\n"));
return False;
}
nsrec->hostname = talloc_strdup( ctx, nsname );
return True;
}
/*********************************************************************
Sort SRV record list based on weight and priority. See RFC 2782.
@ -230,27 +271,16 @@ static int dnssrvcmp( struct dns_rr_srv *a, struct dns_rr_srv *b )
}
/*********************************************************************
Simple wrapper for a DNS SRV query
Simple wrapper for a DNS query
*********************************************************************/
NTSTATUS ads_dns_lookup_srv( TALLOC_CTX *ctx, const char *name, struct dns_rr_srv **dclist, int *numdcs )
static NTSTATUS dns_send_req( TALLOC_CTX *ctx, const char *name, int q_type,
uint8 **buf, int *resp_length )
{
uint8 *buffer = NULL;
size_t buf_len;
int resp_len = NS_PACKETSZ;
struct dns_rr_srv *dcs = NULL;
int query_count, answer_count, auth_count, additional_count;
uint8 *p = buffer;
int rrnum;
int idx = 0;
if ( !ctx || !name || !dclist ) {
return NT_STATUS_INVALID_PARAMETER;
}
int resp_len = NS_PACKETSZ;
/* Send the request. May have to loop several times in case
of large replies */
do {
if ( buffer )
TALLOC_FREE( buffer );
@ -262,13 +292,47 @@ NTSTATUS ads_dns_lookup_srv( TALLOC_CTX *ctx, const char *name, struct dns_rr_sr
return NT_STATUS_NO_MEMORY;
}
if ( (resp_len = res_query(name, C_IN, T_SRV, buffer, buf_len)) < 0 ) {
if ( (resp_len = res_query(name, C_IN, q_type, buffer, buf_len)) < 0 ) {
DEBUG(1,("ads_dns_lookup_srv: Failed to resolve %s (%s)\n", name, strerror(errno)));
TALLOC_FREE( buffer );
return NT_STATUS_UNSUCCESSFUL;
}
} while ( buf_len < resp_len && resp_len < MAX_DNS_PACKET_SIZE );
*buf = buffer;
*resp_length = resp_len;
return NT_STATUS_OK;
}
/*********************************************************************
Simple wrapper for a DNS SRV query
*********************************************************************/
static NTSTATUS ads_dns_lookup_srv( TALLOC_CTX *ctx, const char *name, struct dns_rr_srv **dclist, int *numdcs )
{
uint8 *buffer = NULL;
int resp_len = 0;
struct dns_rr_srv *dcs = NULL;
int query_count, answer_count, auth_count, additional_count;
uint8 *p = buffer;
int rrnum;
int idx = 0;
NTSTATUS status;
if ( !ctx || !name || !dclist ) {
return NT_STATUS_INVALID_PARAMETER;
}
/* Send the request. May have to loop several times in case
of large replies */
status = dns_send_req( ctx, name, T_SRV, &buffer, &resp_len );
if ( !NT_STATUS_IS_OK(status) ) {
DEBUG(0,("ads_dns_lookup_srv: Failed to send DNS query (%s)\n",
nt_errstr(status)));
return status;
}
p = buffer;
/* For some insane reason, the ns_initparse() et. al. routines are only
@ -361,6 +425,125 @@ NTSTATUS ads_dns_lookup_srv( TALLOC_CTX *ctx, const char *name, struct dns_rr_sr
return NT_STATUS_OK;
}
/*********************************************************************
Simple wrapper for a DNS NS query
*********************************************************************/
NTSTATUS ads_dns_lookup_ns( TALLOC_CTX *ctx, const char *dnsdomain, struct dns_rr_ns **nslist, int *numns )
{
uint8 *buffer = NULL;
int resp_len = 0;
struct dns_rr_ns *nsarray = NULL;
int query_count, answer_count, auth_count, additional_count;
uint8 *p;
int rrnum;
int idx = 0;
NTSTATUS status;
if ( !ctx || !dnsdomain || !nslist ) {
return NT_STATUS_INVALID_PARAMETER;
}
/* Send the request. May have to loop several times in case
of large replies */
status = dns_send_req( ctx, dnsdomain, T_NS, &buffer, &resp_len );
if ( !NT_STATUS_IS_OK(status) ) {
DEBUG(0,("ads_dns_lookup_ns: Failed to send DNS query (%s)\n",
nt_errstr(status)));
return status;
}
p = buffer;
/* For some insane reason, the ns_initparse() et. al. routines are only
available in libresolv.a, and not the shared lib. Who knows why....
So we have to parse the DNS reply ourselves */
/* Pull the answer RR's count from the header. Use the NMB ordering macros */
query_count = RSVAL( p, 4 );
answer_count = RSVAL( p, 6 );
auth_count = RSVAL( p, 8 );
additional_count = RSVAL( p, 10 );
DEBUG(4,("ads_dns_lookup_ns: %d records returned in the answer section.\n",
answer_count));
if ( (nsarray = TALLOC_ARRAY(ctx, struct dns_rr_ns, answer_count)) == NULL ) {
DEBUG(0,("ads_dns_lookup_ns: talloc() failure for %d char*'s\n",
answer_count));
return NT_STATUS_NO_MEMORY;
}
/* now skip the header */
p += NS_HFIXEDSZ;
/* parse the query section */
for ( rrnum=0; rrnum<query_count; rrnum++ ) {
struct dns_query q;
if ( !ads_dns_parse_query( ctx, buffer, buffer+resp_len, &p, &q ) ) {
DEBUG(1,("ads_dns_lookup_ns: Failed to parse query record!\n"));
return NT_STATUS_UNSUCCESSFUL;
}
}
/* now we are at the answer section */
for ( rrnum=0; rrnum<answer_count; rrnum++ ) {
if ( !ads_dns_parse_rr_ns( ctx, buffer, buffer+resp_len, &p, &nsarray[rrnum] ) ) {
DEBUG(1,("ads_dns_lookup_ns: Failed to parse answer record!\n"));
return NT_STATUS_UNSUCCESSFUL;
}
}
idx = rrnum;
/* Parse the authority section */
/* just skip these for now */
for ( rrnum=0; rrnum<auth_count; rrnum++ ) {
struct dns_rr rr;
if ( !ads_dns_parse_rr( ctx, buffer, buffer+resp_len, &p, &rr ) ) {
DEBUG(1,("ads_dns_lookup_ns: Failed to parse authority record!\n"));
return NT_STATUS_UNSUCCESSFUL;
}
}
/* Parse the additional records section */
for ( rrnum=0; rrnum<additional_count; rrnum++ ) {
struct dns_rr rr;
int i;
if ( !ads_dns_parse_rr( ctx, buffer, buffer+resp_len, &p, &rr ) ) {
DEBUG(1,("ads_dns_lookup_ns: Failed to parse additional records section!\n"));
return NT_STATUS_UNSUCCESSFUL;
}
/* only interested in A records as a shortcut for having to come
back later and lookup the name */
if ( (rr.type != T_A) || (rr.rdatalen != 4) )
continue;
for ( i=0; i<idx; i++ ) {
if ( strcmp( rr.hostname, nsarray[i].hostname ) == 0 ) {
uint8 *buf = (uint8*)&nsarray[i].ip.s_addr;
memcpy( buf, rr.rdata, 4 );
}
}
}
*nslist = nsarray;
*numns = idx;
return NT_STATUS_OK;
}
/********************************************************************
********************************************************************/