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clamp ttls in the adb to be 10 < ttl < 86400, that is, 10 seconds minimum and 24 hours max

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This commit is contained in:
Michael Graff 2000-06-07 20:15:48 +00:00
parent b483ca1153
commit a14eb88840
1 changed files with 19 additions and 12 deletions
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31
lib/dns/adb.c
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@ -82,6 +82,7 @@
* if the zone has extremely low TTLs.
*/
#define ADB_CACHE_MINIMUM 10 /* seconds */
#define ADB_CACHE_MAXIMUM 86400 /* seconds (86400 = 24 hours) */
/*
* Clean CLEAN_BUCKETS buckets every CLEAN_SECONDS.
@ -424,6 +425,16 @@ DP(int level, const char *format, ...) {
va_end(args);
}
static inline dns_ttl_t
ttlclamp(dns_ttl_t ttl) {
if (ttl < ADB_CACHE_MINIMUM)
ttl = ADB_CACHE_MINIMUM;
if (ttl > ADB_CACHE_MAXIMUM)
ttl = ADB_CACHE_MAXIMUM;
return (ttl);
}
/*
* Requires the adbname bucket be locked and that no entry buckets be locked.
*
@ -521,7 +532,7 @@ import_rdataset(dns_adbname_t *adbname, dns_rdataset_t *rdataset,
if (addr_bucket != DNS_ADB_INVALIDBUCKET)
UNLOCK(&adb->entrylocks[addr_bucket]);
rdataset->ttl = ISC_MAX(rdataset->ttl, ADB_CACHE_MINIMUM);
rdataset->ttl = ttlclamp(rdataset->ttl);
if (rdtype == dns_rdatatype_a) {
DP(NCACHE_LEVEL, "expire_v4 set to MIN(%u,%u) import_rdataset",
@ -3104,7 +3115,7 @@ dbfind_name(dns_adbname_t *adbname, isc_stdtime_t now, dns_rdatatype_t rdtype)
* We found a negative cache entry. Pull the TTL from it
* so we won't ask again for a while.
*/
rdataset.ttl = ISC_MAX(rdataset.ttl, ADB_CACHE_MINIMUM);
rdataset.ttl = ttlclamp(rdataset.ttl);
if (rdtype == dns_rdatatype_a) {
adbname->expire_v4 = rdataset.ttl + now;
DP(NCACHE_LEVEL,
@ -3125,7 +3136,7 @@ dbfind_name(dns_adbname_t *adbname, isc_stdtime_t now, dns_rdatatype_t rdtype)
*/
adbname->flags &= ~(DNS_ADBFIND_GLUEOK | DNS_ADBFIND_HINTOK);
rdataset.ttl = ISC_MAX(rdataset.ttl, ADB_CACHE_MINIMUM);
rdataset.ttl = ttlclamp(rdataset.ttl);
clean_target(adb, &adbname->target);
adbname->expire_target = INT_MAX;
result = set_target(adb, &adbname->name, fname, &rdataset,
@ -3214,7 +3225,7 @@ dbfind_a6(dns_adbname_t *adbname, isc_stdtime_t now) {
break;
case DNS_R_CNAME:
case DNS_R_DNAME:
rdataset.ttl = ISC_MAX(rdataset.ttl, ADB_CACHE_MINIMUM);
rdataset.ttl = ttlclamp(rdataset.ttl);
clean_target(adb, &adbname->target);
adbname->expire_target = INT_MAX;
result = set_target(adb, &adbname->name, fname, &rdataset,
@ -3321,8 +3332,7 @@ fetch_callback(isc_task_t *task, isc_event_t *ev) {
* If we got a negative cache response, remember it.
*/
if (NCACHE_RESULT(dev->result)) {
dev->rdataset->ttl = ISC_MAX(dev->rdataset->ttl,
ADB_CACHE_MINIMUM);
dev->rdataset->ttl = ttlclamp(dev->rdataset->ttl);
if (address_type == DNS_ADBFIND_INET) {
DP(NCACHE_LEVEL, "adb fetch name %p: "
"Caching negative entry for A (ttl %u)",
@ -3343,8 +3353,7 @@ fetch_callback(isc_task_t *task, isc_event_t *ev) {
* Handle CNAME/DNAME.
*/
if (dev->result == DNS_R_CNAME || dev->result == DNS_R_DNAME) {
dev->rdataset->ttl = ISC_MAX(dev->rdataset->ttl,
ADB_CACHE_MINIMUM);
dev->rdataset->ttl = ttlclamp(dev->rdataset->ttl);
clean_target(adb, &name->target);
name->expire_target = INT_MAX;
result = set_target(adb, &name->name,
@ -3483,8 +3492,7 @@ fetch_callback_a6(isc_task_t *task, isc_event_t *ev) {
* If we got a negative cache response, remember it.
*/
if (NCACHE_RESULT(dev->result)) {
dev->rdataset->ttl = ISC_MAX(dev->rdataset->ttl,
ADB_CACHE_MINIMUM);
dev->rdataset->ttl = ttlclamp(dev->rdataset->ttl);
DP(NCACHE_LEVEL, "adb fetch name %p: "
"Caching negative entry for A6 (ttl %u)",
name, dev->rdataset->ttl);
@ -3496,8 +3504,7 @@ fetch_callback_a6(isc_task_t *task, isc_event_t *ev) {
* Handle CNAME/DNAME.
*/
if (dev->result == DNS_R_CNAME || dev->result == DNS_R_DNAME) {
dev->rdataset->ttl = ISC_MAX(dev->rdataset->ttl,
ADB_CACHE_MINIMUM);
dev->rdataset->ttl = ttlclamp(dev->rdataset->ttl);
clean_target(adb, &name->target);
name->expire_target = INT_MAX;
result = set_target(adb, &name->name,