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Code Issues Releases Wiki Activity

2874. [bug] Cache lack of EDNS support only after the server

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successfully responds to the query using plain DNS.
                        [RT #20930]
This commit is contained in:
Mark Andrews 2010-04-20 07:28:52 +00:00
parent 7ac3315851
commit 1e9848fb2b
2 changed files with 70 additions and 10 deletions
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4
CHANGES
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@ -1,3 +1,7 @@
2874. [bug] Cache lack of EDNS support only after the server
successfully responds to the query using plain DNS.
[RT #20930]
2873. [bug] Canceling a dynamic update via the dns/client module
could trigger an assertion failure. [RT #21133]

76
lib/dns/resolver.c
View File

@ -15,7 +15,7 @@
* PERFORMANCE OF THIS SOFTWARE.
*/
/* $Id: resolver.c,v 1.419 2010/03/04 22:25:31 marka Exp $ */
/* $Id: resolver.c,v 1.420 2010/04/20 07:28:52 marka Exp $ */
/*! \file */
@ -203,6 +203,7 @@ struct fetchctx {
isc_sockaddrlist_t bad;
isc_sockaddrlist_t edns;
isc_sockaddrlist_t edns512;
isc_sockaddrlist_t bad_edns;
dns_validator_t *validator;
ISC_LIST(dns_validator_t) validators;
dns_db_t * cache;
@ -1561,6 +1562,36 @@ fctx_query(fetchctx_t *fctx, dns_adbaddrinfo_t *addrinfo,
return (result);
}
static isc_boolean_t
bad_edns(fetchctx_t *fctx, isc_sockaddr_t *address) {
isc_sockaddr_t *sa;
for (sa = ISC_LIST_HEAD(fctx->bad_edns);
sa != NULL;
sa = ISC_LIST_NEXT(sa, link)) {
if (isc_sockaddr_equal(sa, address))
return (ISC_TRUE);
}
return (ISC_FALSE);
}
static void
add_bad_edns(fetchctx_t *fctx, isc_sockaddr_t *address) {
isc_sockaddr_t *sa;
if (bad_edns(fctx, address))
return;
sa = isc_mem_get(fctx->res->buckets[fctx->bucketnum].mctx,
sizeof(*sa));
if (sa == NULL)
return;
*sa = *address;
ISC_LIST_INITANDAPPEND(fctx->bad_edns, sa, link);
}
static isc_boolean_t
triededns(fetchctx_t *fctx, isc_sockaddr_t *address) {
isc_sockaddr_t *sa;
@ -3129,6 +3160,14 @@ fctx_destroy(fetchctx_t *fctx) {
isc_mem_put(res->buckets[bucketnum].mctx, sa, sizeof(*sa));
}
for (sa = ISC_LIST_HEAD(fctx->bad_edns);
sa != NULL;
sa = next_sa) {
next_sa = ISC_LIST_NEXT(sa, link);
ISC_LIST_UNLINK(fctx->bad_edns, sa, link);
isc_mem_put(res->buckets[bucketnum].mctx, sa, sizeof(*sa));
}
isc_timer_detach(&fctx->timer);
dns_message_destroy(&fctx->rmessage);
dns_message_destroy(&fctx->qmessage);
@ -3500,6 +3539,7 @@ fctx_create(dns_resolver_t *res, dns_name_t *name, dns_rdatatype_t type,
ISC_LIST_INIT(fctx->bad);
ISC_LIST_INIT(fctx->edns);
ISC_LIST_INIT(fctx->edns512);
ISC_LIST_INIT(fctx->bad_edns);
ISC_LIST_INIT(fctx->validators);
fctx->validator = NULL;
fctx->find = NULL;
@ -6620,7 +6660,26 @@ resquery_response(isc_task_t *task, isc_event_t *event) {
* ensured by the dispatch code).
*/
/*
* We have an affirmative response to the query and we have
* previously got a response from this server which indicated
* EDNS may not be supported so we can now cache the lack of
* EDNS support.
*/
if (opt == NULL &&
(message->rcode == dns_rcode_noerror ||
message->rcode == dns_rcode_nxdomain ||
message->rcode == dns_rcode_refused ||
message->rcode == dns_rcode_yxdomain) &&
bad_edns(fctx, &query->addrinfo->sockaddr)) {
char addrbuf[ISC_SOCKADDR_FORMATSIZE];
isc_sockaddr_format(&query->addrinfo->sockaddr, addrbuf,
sizeof(addrbuf));
dns_adb_changeflags(fctx->adb, query->addrinfo,
DNS_FETCHOPT_NOEDNS0,
DNS_FETCHOPT_NOEDNS0);
}
/*
* Deal with truncated responses by retrying using TCP.
*/
@ -6675,9 +6734,9 @@ resquery_response(isc_task_t *task, isc_event_t *event) {
if (message->rcode != dns_rcode_noerror &&
message->rcode != dns_rcode_nxdomain) {
if (((message->rcode == dns_rcode_formerr ||
message->rcode == dns_rcode_notimp) ||
(message->rcode == dns_rcode_servfail &&
dns_message_getopt(message) == NULL)) &&
message->rcode == dns_rcode_notimp) ||
(message->rcode == dns_rcode_servfail &&
dns_message_getopt(message) == NULL)) &&
(query->options & DNS_FETCHOPT_NOEDNS0) == 0) {
/*
* It's very likely they don't like EDNS0.
@ -6693,12 +6752,9 @@ resquery_response(isc_task_t *task, isc_event_t *event) {
options |= DNS_FETCHOPT_NOEDNS0;
resend = ISC_TRUE;
/*
* Remember that they don't like EDNS0.
* Remember that they may not like EDNS0.
*/
if (message->rcode != dns_rcode_servfail)
dns_adb_changeflags(fctx->adb, query->addrinfo,
DNS_FETCHOPT_NOEDNS0,
DNS_FETCHOPT_NOEDNS0);
add_bad_edns(fctx, &query->addrinfo->sockaddr);
inc_stats(fctx->res, dns_resstatscounter_edns0fail);
} else if (message->rcode == dns_rcode_formerr) {
if (ISFORWARDER(query->addrinfo)) {