mir/bind
2
0
Fork 0
mirror of https://gitlab.isc.org/isc-projects/bind9 synced 2025-08-31 06:25:31 +00:00
Code Issues Releases Wiki Activity

781. [func] Avoid error packet loops by dropping duplicate FORMERR

Browse Source 
responses. [RT #1006]
This commit is contained in:
Andreas Gustafsson
2001-03-19 20:52:21 +00:00
parent 484deb5c3e
commit 4c03e69ab8
3 changed files with 51 additions and 2 deletions
Download Patch File Download Diff File Expand all files Collapse all files

36
bin/named/client.c
View File

@@ -15,7 +15,7 @@
* WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
/* $Id: client.c,v 1.159 2001/03/12 22:27:14 bwelling Exp $ */
/* $Id: client.c,v 1.160 2001/03/19 20:52:19 gson Exp $ */
#include <config.h>
@@ -950,6 +950,33 @@ ns_client_error(ns_client_t *client, isc_result_t result) {
}
}
message->rcode = rcode;
/*
* FORMERR loop avoidance: If we sent a FORMERR message
* with the same ID to the same client less than two
* seconds ago, assume that we are in an infinite error
* packet dialog with a server for some protocol whose
* error responses look enough like DNS queries to
* elicit a FORMERR response. Drop a packet to break
* the loop.
*/
if (rcode == dns_rcode_formerr) {
if (isc_sockaddr_equal(&client->peeraddr,
&client->formerrcache.addr) &&
message->id == client->formerrcache.id &&
client->requesttime - client->formerrcache.time < 2) {
/* Drop packet. */
ns_client_log(client, NS_LOGCATEGORY_CLIENT,
NS_LOGMODULE_CLIENT, ISC_LOG_DEBUG(1),
"possible error packet loop, "
"FORMERR dropped");
ns_client_next(client, result);
return;
}
client->formerrcache.addr = client->peeraddr;
client->formerrcache.time = client->requesttime;
client->formerrcache.id = message->id;
}
ns_client_send(client);
}
@@ -1618,6 +1645,13 @@ client_create(ns_clientmgr_t *manager, ns_client_t **clientp)
ISC_EVENT_INIT(&client->ctlevent, sizeof(client->ctlevent), 0, NULL,
NS_EVENT_CLIENTCONTROL, client_start, client, client,
NULL, NULL);
/*
* Initialize FORMERR cache to sentinel value that will not match
* any actual FORMERR response.
*/
isc_sockaddr_any(&client->formerrcache.addr);
client->formerrcache.time = 0;
client->formerrcache.id = 0;
ISC_LINK_INIT(client, link);
client->list = NULL;