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Fix wrong query accounting in the connect function in dighost.c

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The start_udp() function didn't properly attach to the query and thus
a callback with ISC_R_CANCELED would end with wrong accounting on the
query object.

Usually, this doesn't happen because underlying libuv API
uv_udp_connect() is synchronous, but isc_nm_udpconnect() could return
ISC_R_CANCELED in case it's called while the netmgr is shutting down.
This commit is contained in:
Ondřej Surý 2021-04-27 12:03:20 +02:00 committed by Evan Hunt
parent dacf586e18
commit 2836bc1854
1 changed files with 14 additions and 8 deletions
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22
bin/dig/dighost.c
View file

@ -227,8 +227,9 @@ void (*dighost_shutdown)(void);
/* forward declarations */
#define cancel_lookup(l) _cancel_lookup(l, __FILE__, __LINE__)
static void
cancel_lookup(dig_lookup_t *lookup);
_cancel_lookup(dig_lookup_t *lookup, const char *file, unsigned int line);
static void
recv_done(isc_nmhandle_t *handle, isc_result_t eresult, isc_region_t *region,
@ -1694,6 +1695,9 @@ _query_detach(dig_query_t **queryp, const char *file, unsigned int line) {
isc_refcount_current(&query->references) - 1);
if (isc_refcount_decrement(&query->references) == 1) {
INSIST(query->readhandle == NULL);
INSIST(query->sendhandle == NULL);
if (ISC_LINK_LINKED(query, link)) {
ISC_LIST_UNLINK(lookup->q, query, link);
}
@ -2669,11 +2673,12 @@ send_done(isc_nmhandle_t *handle, isc_result_t eresult, void *arg) {
/*%
* Cancel a lookup, sending canceling reads on all existing sockets.
*/
static void
cancel_lookup(dig_lookup_t *lookup) {
_cancel_lookup(dig_lookup_t *lookup, const char *file, unsigned int line) {
dig_query_t *query, *next;
debug("cancel_lookup()");
debug("%s:%u:%s()", file, line, __func__);
query = ISC_LIST_HEAD(lookup->q);
while (query != NULL) {
REQUIRE(DIG_VALID_QUERY(query));
@ -2939,6 +2944,7 @@ static void
start_udp(dig_query_t *query) {
isc_result_t result;
dig_query_t *next = NULL;
dig_query_t *connectquery = NULL;
REQUIRE(DIG_VALID_QUERY(query));
@ -2990,8 +2996,10 @@ start_udp(dig_query_t *query) {
}
}
query_attach(query, &connectquery);
isc_nm_udpconnect(netmgr, (isc_nmiface_t *)&localaddr,
(isc_nmiface_t *)&query->sockaddr, udp_ready, query,
(isc_nmiface_t *)&query->sockaddr, udp_ready,
connectquery,
(timeout ? timeout : UDP_TIMEOUT) * 1000, 0);
}
@ -4186,15 +4194,13 @@ cancel_all(void) {
return;
}
atomic_store(&cancel_now, true);
if (current_lookup != NULL) {
while (current_lookup != NULL) {
for (q = ISC_LIST_HEAD(current_lookup->q); q != NULL; q = nq) {
nq = ISC_LIST_NEXT(q, link);
debug("canceling pending query %p, belonging to %p", q,
current_lookup);
if (q->readhandle != NULL) {
isc_refcount_decrement0(&recvcount);
debug("recvcount=%" PRIuFAST32,
isc_refcount_current(&recvcount));
isc_nm_cancelread(q->readhandle);
}
query_detach(&q);
}