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first try at type 3 negative responses

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This commit is contained in:
Bob Halley
1999-11-03 03:20:34 +00:00
parent 75841ddeb0
commit 55254a46f9
1 changed files with 57 additions and 12 deletions
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69
lib/dns/ncache.c
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@@ -95,14 +95,14 @@ dns_ncache_add(dns_message_t *message, dns_db_t *cache, dns_dbnode_t *node,
isc_buffer_t buffer; isc_buffer_t buffer;
isc_region_t r; isc_region_t r;
dns_rdataset_t *rdataset; dns_rdataset_t *rdataset;
dns_rdata_t rdata;
dns_rdataset_t ncrdataset;
dns_rdatalist_t ncrdatalist;
dns_rdatatype_t type; dns_rdatatype_t type;
dns_name_t *name; dns_name_t *name;
dns_ttl_t ttl; dns_ttl_t ttl;
char *data[4096];
dns_trust_t trust; dns_trust_t trust;
dns_rdata_t rdata;
dns_rdataset_t ncrdataset;
dns_rdatalist_t ncrdatalist;
unsigned char data[4096];
/* /*
* Convert the authority data from 'message' into a negative cache * Convert the authority data from 'message' into a negative cache
@@ -173,11 +173,58 @@ dns_ncache_add(dns_message_t *message, dns_db_t *cache, dns_dbnode_t *node,
if (result != ISC_R_NOMORE) if (result != ISC_R_NOMORE)
return (result); return (result);
/* if (trust == 0xffff) {
* Now, turn 'buffer' into an ncache rdataset and add it to /*
* the cache. * We didn't find any authority data from which to create a
*/ * negative cache rdataset. In particular, we have no SOA.
*
* We trust that the caller wants negative caching, so this
* means we have a "type 3 nxdomain" or "type 3 nodata"
* response (see RFC 2308 for details).
*
* We will now build a suitable negative cache rdataset that
* will cause zero bytes to be emitted when converted to
* wire format.
*/
/*
* The ownername must exist, but it doesn't matter what value
* it has. We use the root name.
*/
dns_name_toregion(dns_rootname, &r);
result = isc_buffer_copyregion(&buffer, &r);
if (result != ISC_R_SUCCESS)
return (result);
/*
* Copy the type and a zero rdata count to the buffer.
*/
isc_buffer_available(&buffer, &r);
if (r.length < 4)
return (ISC_R_NOSPACE);
isc_buffer_putuint16(&buffer, 0);
isc_buffer_putuint16(&buffer, 0);
/*
* RFC 2308, section 5, says that negative answers without
* SOAs should not be cached.
*/
ttl = 0;
/*
* Set trust.
*/
if ((message->flags & DNS_MESSAGEFLAG_AA) != 0 &&
message->counts[DNS_SECTION_ANSWER] == 0) {
/*
* The response has aa set and we haven't followed
* any CNAME or DNAME chains.
*/
trust = dns_trust_authauthority;
} else
trust = dns_trust_additional;
}
/*
* Now add it to the cache.
*/
INSIST(trust != 0xffff); INSIST(trust != 0xffff);
dns_rdata_init(&rdata); dns_rdata_init(&rdata);
isc_buffer_used(&buffer, &r); isc_buffer_used(&buffer, &r);
@@ -199,10 +246,8 @@ dns_ncache_add(dns_message_t *message, dns_db_t *cache, dns_dbnode_t *node,
dns_rdatalist_tordataset(&ncrdatalist, &ncrdataset); dns_rdatalist_tordataset(&ncrdatalist, &ncrdataset);
ncrdataset.trust = trust; ncrdataset.trust = trust;
result = dns_db_addrdataset(cache, node, NULL, now, &ncrdataset, return (dns_db_addrdataset(cache, node, NULL, now, &ncrdataset,
ISC_FALSE, addedrdataset); ISC_FALSE, addedrdataset));
return (result);
} }
isc_result_t isc_result_t