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Merge branch '3128-dig-does-not-recover-from-a-isc_nm_udpconnect-failure' into 'main'

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After dig request errors, try to use other servers when they exist

Closes #3128

See merge request isc-projects/bind9!5967
This commit is contained in:
Arаm Sаrgsyаn
2022-03-18 10:24:46 +00:00
parent da0d85d748 b3a058e7bb
commit 85870ad9ee
3 changed files with 123 additions and 32 deletions
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4
CHANGES
View File

@@ -1,3 +1,7 @@
5832. [bug] When timing-out or having other types of socket errors
during a query, dig wasn't trying to perform the lookup
using other servers, in case they exist. [GL #3128]
5831. [bug] When resending a UDP request in the result of a timeout,
the recv_done() function in dighost.c was prepending
the new query into the loookup's queries list instead

133
bin/dig/dighost.c
View File

@@ -3280,9 +3280,9 @@ tcp_connected(isc_nmhandle_t *handle, isc_result_t eresult, void *arg) {
}
if (l->retries > 1) {
l->retries--;
debug("making new TCP request, %d tries left",
l->retries);
l->retries--;
requeue_lookup(l, true);
next = NULL;
} else if ((l->current_query != NULL) &&
@@ -3622,50 +3622,119 @@ recv_done(isc_nmhandle_t *handle, isc_result_t eresult, isc_region_t *region,
TIME_NOW(&query->time_recv);
}
if (eresult == ISC_R_TIMEDOUT && !l->tcp_mode && l->retries > 1) {
dig_query_t *newq = NULL;
l->retries--;
debug("making new UDP request, %d tries left", l->retries);
newq = new_query(l, query->servname, query->userarg);
ISC_LIST_INSERTAFTER(l->q, query, newq, link);
if (l->current_query == query) {
query_detach(&l->current_query);
}
start_udp(newq);
goto detach_query;
}
if ((!l->pending && !l->ns_search_only) || atomic_load(&cancel_now)) {
debug("no longer pending. Got %s", isc_result_totext(eresult));
goto next_lookup;
}
if (eresult != ISC_R_SUCCESS) {
if (eresult == ISC_R_TIMEDOUT) {
if (l->retries > 1 && !l->tcp_mode) {
dig_query_t *newq = NULL;
/*
* For UDP, insert a copy of the current query just
* after itself in the list, and start it to retry the
* request.
*/
newq = new_query(l, query->servname, query->userarg);
ISC_LIST_INSERTAFTER(l->q, query, newq, link);
if (l->current_query == query) {
query_detach(&l->current_query);
}
if (l->current_query == NULL) {
l->retries--;
debug("making new UDP request, %d tries left",
l->retries);
start_udp(newq);
}
goto detach_query;
} else if (l->retries > 1 && l->tcp_mode) {
/*
* For TCP, we have to requeue the whole lookup, see
* the comments above the start_tcp() function.
*/
l->retries--;
debug("making new TCP request, %d tries left",
l->retries);
requeue_lookup(l, true);
if (keep != NULL) {
isc_nmhandle_detach(&keep);
}
goto cancel_lookup;
} else {
dig_query_t *next = ISC_LIST_NEXT(query, link);
/*
* No retries left, go to the next query, if there is
* one.
*/
if (next != NULL) {
if (l->current_query == query) {
query_detach(&l->current_query);
}
if (l->current_query == NULL) {
debug("starting next query %p", next);
if (l->tcp_mode) {
start_tcp(next);
} else {
start_udp(next);
}
}
goto detach_query;
}
/*
* Otherwise, print the cmdline and an error message,
* and cancel the lookup.
*/
printf("%s", l->cmdline);
dighost_error("connection timed out; "
"no servers could be reached\n");
if (exitcode < 9) {
exitcode = 9;
}
if (keep != NULL) {
isc_nmhandle_detach(&keep);
}
goto cancel_lookup;
}
} else if (eresult != ISC_R_SUCCESS) {
dig_query_t *next = ISC_LIST_NEXT(query, link);
char sockstr[ISC_SOCKADDR_FORMATSIZE];
isc_sockaddr_format(&query->sockaddr, sockstr, sizeof(sockstr));
if (eresult == ISC_R_TIMEDOUT) {
if (l->retries > 1) {
debug("making new TCP request, %d tries left",
l->retries);
l->retries--;
requeue_lookup(l, true);
} else {
printf("%s", l->cmdline);
dighost_error("connection timed out; "
"no servers could be reached\n");
if (exitcode < 9) {
exitcode = 9;
/*
* There was a communication error with the current query,
* go to the next query, if there is one.
*/
if (next != NULL) {
if (l->current_query == query) {
query_detach(&l->current_query);
}
if (l->current_query == NULL) {
debug("starting next query %p", next);
if (l->tcp_mode) {
start_tcp(next);
} else {
start_udp(next);
}
}
} else {
dighost_error("communications error to %s: %s\n",
sockstr, isc_result_totext(eresult));
goto detach_query;
}
/*
* Otherwise, print an error message and cancel the
* lookup.
*/
dighost_error("communications error to %s: %s\n", sockstr,
isc_result_totext(eresult));
if (keep != NULL) {
isc_nmhandle_detach(&keep);
}

18
bin/tests/system/digdelv/tests.sh
View File

@@ -1014,6 +1014,24 @@ if [ -x "$DIG" ] ; then
grep "status: SERVFAIL" dig.out.test$n > /dev/null || ret=1
if [ $ret -ne 0 ]; then echo_i "failed"; fi
status=$((status+ret))
n=$((n+1))
echo_i "check that dig tries the next server after a connection error ($n)"
ret=0
dig_with_opts -d @10.53.0.99 @10.53.0.3 a.example > dig.out.test$n 2>&1 || ret=1
grep "status: NOERROR" dig.out.test$n > /dev/null || ret=1
if [ $ret -ne 0 ]; then echo_i "failed"; fi
status=$((status+ret))
n=$((n+1))
echo_i "check that dig tries the next server after timeouts ($n)"
# Ask ans4 to not respond to queries
echo "//" | sendcmd 10.53.0.4
ret=0
dig_with_opts -d @10.53.0.4 @10.53.0.3 a.example > dig.out.test$n 2>&1 || ret=1
grep "status: NOERROR" dig.out.test$n > /dev/null || ret=1
if [ $ret -ne 0 ]; then echo_i "failed"; fi
status=$((status+ret))
else
echo_i "$DIG is needed, so skipping these dig tests"
fi