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netmgr: don't send to an inactive (closing) udp socket

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We had a race in which n UDP socket could have been already closing
by libuv but we still sent data to it. Mark socket as not-active
when stopping listening and verify that socket is not active when
trying to send data to it.
This commit is contained in:
Witold Kręcicki
2020-01-16 11:52:58 +01:00
parent 402f067fc0
commit 16908ec3d9
3 changed files with 21 additions and 5 deletions
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7
lib/isc/netmgr/netmgr-int.h
View File

@@ -603,6 +603,13 @@ isc__nmsocket_prep_destroy(isc_nmsocket_t *sock);
* if there are no remaining references or active handles.
*/
bool
isc__nmsocket_active(isc_nmsocket_t *sock);
/*%<
* Check is socket 'sock' is active - by checking either sock->active or
* sock->parent->active;
*/
void
isc__nm_async_closecb(isc__networker_t *worker, isc__netievent_t *ev0);
/*%<

2
lib/isc/netmgr/netmgr.c
View File

@@ -681,7 +681,7 @@ isc__nm_enqueue_ievent(isc__networker_t *worker, isc__netievent_t *event) {
uv_async_send(&worker->async);
}
static bool
bool
isc__nmsocket_active(isc_nmsocket_t *sock) {
REQUIRE(VALID_NMSOCK(sock));
if (sock->parent != NULL) {

17
lib/isc/netmgr/udp.c
View File

@@ -179,14 +179,18 @@ stop_udp_child(isc_nmsocket_t *sock) {
static void
stoplistening(isc_nmsocket_t *sock) {
INSIST(sock->type == isc_nm_udplistener);
/*
* Socket is already closing; there's nothing to do.
*/
if (uv_is_closing((uv_handle_t *) &sock->uv_handle.udp)) {
if (!isc__nmsocket_active(sock)) {
return;
}
INSIST(sock->type == isc_nm_udplistener);
/*
* Mark it inactive now so that all sends will be ignored
* and we won't try to stop listening again.
*/
atomic_store(&sock->active, false);
for (int i = 0; i < sock->nchildren; i++) {
isc__netievent_udpstop_t *event = NULL;
@@ -375,6 +379,11 @@ isc__nm_udp_send(isc_nmhandle_t *handle, isc_region_t *region,
return (ISC_R_UNEXPECTED);
}
if (!isc__nmsocket_active(sock)) {
isc_nmhandle_unref(handle);
return (ISC_R_CANCELED);
}
if (isc__nm_in_netthread()) {
ntid = isc_nm_tid();
} else {
@@ -425,7 +434,7 @@ isc__nm_async_udpsend(isc__networker_t *worker, isc__netievent_t *ev0) {
REQUIRE(worker->id == ievent->sock->tid);
if (atomic_load(&ievent->sock->active)) {
if (isc__nmsocket_active(ievent->sock)) {
udp_send_direct(ievent->sock, ievent->req, &ievent->peer);
} else {
ievent->req->cb.send(ievent->req->handle,