* PERFORMANCE OF THIS SOFTWARE.
*/
-/* $Id: adb.c,v 1.247.172.12 2011/12/05 16:57:26 each Exp $ */
+/* $Id: adb.c,v 1.247.172.13 2011/12/05 17:24:16 each Exp $ */
/*! \file
*
* name.
*/
-
- unsigned int edns_big_size;
- unsigned int edns_last_size;
- unsigned int edns_fetch_flag;
- unsigned int edns_drop_count;
- isc_stdtime_t edns_drop_timestamp;
- isc_stdtime_t edns_expires_timestamp;
- isc_boolean_t edns_timer_set;
- /*%<
- * The above fields beginning with edns_* determine
- * past success with edns for this server.
- * edns_big_size - biggest successful size received (e.g., 512)
- * edns_last_size - last packet size received
- * edns_fetch_flag - current EDNS state for this server (one of
- * DNS_FETCHOPT_NOEDNS0, DNS_FETCHOPT_EDNS512 or
- * 0 meaning use DNS_ADB_EDNS0_MAX_LEN)
- * edns_drop_count - keeps count of the number of times EDNS udpsize
- * was dropped - reset to 0 every
- * DNS_ADB_EDNS_RESET_TIME
- * edns_drop_timestamp - The time at which the first EDNS drop
- * in packet size was recorded
- *
- * See also dns_adb_drop/setednssize()
- */
-
ISC_LIST(dns_adblameinfo_t) lameinfo;
ISC_LINK(dns_adbentry_t) plink;
UNLOCK(&adb->entrylocks[bucket]);
}
-unsigned int
-dns_adb_getednsflag(dns_adb_t *adb, dns_adbaddrinfo_t *addr, isc_stdtime_t now)
-{
- int bucket = 0;
- int flag_to_use = 0; /* assume max by default */
-
- REQUIRE(DNS_ADB_VALID(adb));
- REQUIRE(DNS_ADBADDRINFO_VALID(addr));
-
- /*
- * The purpose of this function is to return
- * edns_fetch_flag, which effectively sets the udpsize for EDNS
- * or turns off EDNS (if NOEDNS0 has been recorded).
- *
- * Also, this function checks to see if the timer needs resetting.
- * ---> this part should really be done via a callback?
- */
-
- bucket = addr->entry->lock_bucket;
- LOCK(&adb->entrylocks[bucket]);
-
- if((addr->entry->edns_timer_set) &&
- (now >= addr->entry->edns_expires_timestamp)) {
-
- /* Eventually, we may support more sizes */
- if((addr->entry->edns_big_size <= 512) &&
- (addr->entry->edns_big_size > 0))
- flag_to_use = DNS_FETCHOPT_EDNS512;
-
- addr->entry->edns_fetch_flag = flag_to_use;
- addr->entry->edns_expires_timestamp = 0;
- addr->entry->edns_timer_set = isc_boolean_false;
-
- }
-
- flag_to_use = addr->entry->edns_fetch_flag;
-
- UNLOCK(&adb->entrylocks[bucket]);
-
- return(flag_to_use);
-}
-
-void
-dns_adb_setednssize(dns_adb_t *adb, dns_adbaddrinfo_t *addr,
- unsigned int length)
-{
- int bucket = 0;
- unsigned int length_to_use;
-
- REQUIRE(DNS_ADB_VALID(adb));
- REQUIRE(DNS_ADBADDRINFO_VALID(addr));
-
- bucket = addr->entry->lock_bucket;
- LOCK(&adb->entrylocks[bucket]);
-
- /*
- * The purpose of this function is to record
- * the maximum sized udp response seen from the
- * instant server.
- */
-
- length_to_use = addr->entry->edns_big_size;
-
- if (length > DNS_ADB_EDNS0_MAX_LEN)
- length = DNS_ADB_EDNS0_MAX_LEN;
- if (length < DNS_ADB_EDNS0_MIN_LEN)
- length = DNS_ADB_EDNS0_MIN_LEN;
- if (length > length_to_use)
- length_to_use = length;
-
- addr->entry->edns_big_size = length_to_use;
-
- UNLOCK(&adb->entrylocks[bucket]);
-}
-
-void
-dns_adb_dropednssize(dns_adb_t *adb, dns_adbaddrinfo_t *addr,
- unsigned int length, isc_stdtime_t now)
-{
- isc_stdtime_t expires_ts_to_use;
- isc_boolean_t timer_setting_to_use;
- unsigned int length_to_use;
- unsigned int drop_counter_to_use;
- unsigned int drop_ts_to_use;
- unsigned int flag_to_use;
- int bucket = 0;
-
- REQUIRE(DNS_ADB_VALID(adb));
- REQUIRE(DNS_ADBADDRINFO_VALID(addr));
-
- if (length > DNS_ADB_EDNS0_MAX_LEN)
- length = DNS_ADB_EDNS0_MAX_LEN;
- if (length < DNS_ADB_EDNS0_MIN_LEN)
- length = DNS_ADB_EDNS0_MIN_LEN;
-
- bucket = addr->entry->lock_bucket;
- LOCK(&adb->entrylocks[bucket]);
-
- expires_ts_to_use = addr->entry->edns_expires_timestamp;
- timer_setting_to_use = addr->entry->edns_timer_set;
- length_to_use = addr->entry->edns_big_size;
- drop_ts_to_use = addr->entry->edns_drop_timestamp;
- flag_to_use = addr->entry->edns_fetch_flag;
-
- /*
- * This function keeps a count of the number of times
- * within DNS_ADB_EDNS_RESET_TIME that a particular server
- * has dropped the udpsize in order to communicate with the
- * server. If the number of times this occurs exceeds
- * DNS_ADB_EDNS_MAX_DROP_COUNT, then the udpsize is reduced
- * by way of edns_fetch_flag for DNS_ADB_EDNS_MAX_DROP_TIME,
- * after which the largest size is retried again.
- * NOTE: currently, only 4096 and 512 are supported sizes
- */
-
- if (length > length_to_use)
- length_to_use = length;
-
- if ((now - addr->entry->edns_drop_timestamp) >=
- DNS_ADB_EDNS_RESET_TIME) {
-
- drop_counter_to_use = 1;
- drop_ts_to_use = now;
- } else {
-
- drop_counter_to_use = addr->entry->edns_drop_count + 1;
-
- if (drop_counter_to_use >= DNS_ADB_EDNS_MAX_DROP_COUNT) {
- /*
- * At this point, we are dropping down the
- * udpsize because we've had too many misses
- * at larger sizes.
- */
- if (timer_setting_to_use == isc_boolean_false) {
- /*
- * if we haven't already set a timer,
- * do so now. After DNS_ADB_EDNS_MAX_DROP_TIME,
- * we'll go back to the largest size
- */
- expires_ts_to_use =
- now + DNS_ADB_EDNS_MAX_DROP_TIME;
- timer_setting_to_use = isc_boolean_true;
- }
-
- if (length == 0)
- flag_to_use = DNS_FETCHOPT_NOEDNS0;
- else /* eventually, more edns sizes here */
- flag_to_use = DNS_FETCHOPT_EDNS512;
-
- drop_ts_to_use = 0;
- drop_counter_to_use = 0;
- }
- }
-
- addr->entry->edns_drop_timestamp = drop_ts_to_use;
- addr->entry->edns_drop_count = drop_counter_to_use;
- addr->entry->edns_fetch_flag = flag_to_use;
- addr->entry->edns_expires_timestamp = expires_ts_to_use;
- addr->entry->edns_timer_set = timer_setting_to_use;
- addr->entry->edns_big_size = length_to_use;
-
- UNLOCK(&adb->entrylocks[bucket]);
-}
-
void
dns_adb_changeflags(dns_adb_t *adb, dns_adbaddrinfo_t *addr,
unsigned int bits, unsigned int mask)
projects / thirdparty / bind9.git / commitdiff
