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Code Issues Releases Wiki Activity

Make it possible to recover from connect timeouts

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Similarly to the read timeout, it's now possible to recover from
ISC_R_TIMEDOUT event by restarting the timer from the connect callback.

The change here also fixes platforms that missing the socket() options
to set the TCP connection timeout, by moving the timeout code into user
space.  On platforms that support setting the connect timeout via a
socket option, the timeout has been hardcoded to 2 minutes (the maximum
value of tcp-initial-timeout).
This commit is contained in:
Ondřej Surý
2021-03-30 09:25:09 +02:00
parent 33c00c281f
commit 5a87c7372c
7 changed files with 323 additions and 157 deletions
Download Patch File Download Diff File Expand all files Collapse all files

74
lib/isc/netmgr/tcpdns.c
View File

@@ -137,6 +137,9 @@ tcpdns_connect_direct(isc_nmsocket_t *sock, isc__nm_uvreq_t *req) {
}
isc__nm_incstats(sock->mgr, sock->statsindex[STATID_CONNECT]);
uv_handle_set_data((uv_handle_t *)&sock->timer, &req->uv_req.connect);
isc__nmsocket_timer_start(sock);
atomic_store(&sock->connected, true);
done:
@@ -193,20 +196,31 @@ tcpdns_connect_cb(uv_connect_t *uvreq, int status) {
REQUIRE(VALID_NMSOCK(sock));
REQUIRE(sock->tid == isc_nm_tid());
REQUIRE(atomic_load(&sock->connecting));
isc__nmsocket_timer_stop(sock);
uv_handle_set_data((uv_handle_t *)&sock->timer, sock);
req = uv_handle_get_data((uv_handle_t *)uvreq);
REQUIRE(VALID_UVREQ(req));
REQUIRE(VALID_NMHANDLE(req->handle));
/* Socket was closed midflight by isc__nm_tcpdns_shutdown() */
if (!isc__nmsocket_active(sock)) {
if (!atomic_load(&sock->connecting)) {
/*
* The connect was cancelled from timeout; just clean up
* the req.
*/
isc__nm_uvreq_put(&req, sock);
return;
} else if (!isc__nmsocket_active(sock)) {
/* Socket was closed midflight by isc__nm_tcpdns_shutdown() */
result = ISC_R_CANCELED;
goto error;
}
if (status != 0) {
} else if (status == UV_ETIMEDOUT) {
/* Timeout status code here indicates hard error */
result = ISC_R_CANCELED;
goto error;
} else if (status != 0) {
result = isc__nm_uverr2result(status);
goto error;
}
@@ -224,7 +238,7 @@ tcpdns_connect_cb(uv_connect_t *uvreq, int status) {
result = isc_sockaddr_fromsockaddr(&sock->peer, (struct sockaddr *)&ss);
RUNTIME_CHECK(result == ISC_R_SUCCESS);
isc__nm_connectcb(sock, req, ISC_R_SUCCESS);
isc__nm_connectcb(sock, req, ISC_R_SUCCESS, false);
return;
@@ -267,7 +281,7 @@ isc_nm_tcpdnsconnect(isc_nm_t *mgr, isc_nmiface_t *local, isc_nmiface_t *peer,
sock->fd = fd;
atomic_init(&sock->client, true);
result = isc__nm_socket_connectiontimeout(fd, timeout);
result = isc__nm_socket_connectiontimeout(fd, 120 * 1000); /* 2 mins */
RUNTIME_CHECK(result == ISC_R_SUCCESS);
req = isc__nm_uvreq_get(mgr, sock);
@@ -1167,11 +1181,7 @@ tcpdns_stop_cb(uv_handle_t *handle) {
}
static void
tcpdns_close_cb(uv_handle_t *handle) {
isc_nmsocket_t *sock = uv_handle_get_data(handle);
uv_handle_set_data(handle, NULL);
tcpdns_close_sock(isc_nmsocket_t *sock) {
REQUIRE(VALID_NMSOCK(sock));
REQUIRE(sock->tid == isc_nm_tid());
REQUIRE(atomic_load(&sock->closing));
@@ -1194,12 +1204,25 @@ tcpdns_close_cb(uv_handle_t *handle) {
}
static void
timer_close_cb(uv_handle_t *handle) {
tcpdns_close_cb(uv_handle_t *handle) {
isc_nmsocket_t *sock = uv_handle_get_data(handle);
uv_handle_set_data(handle, NULL);
tcpdns_close_sock(sock);
}
static void
timer_close_cb(uv_handle_t *timer) {
isc_nmsocket_t *sock = uv_handle_get_data(timer);
uv_handle_set_data(timer, NULL);
REQUIRE(VALID_NMSOCK(sock));
if (sock->parent) {
uv_close(&sock->uv_handle.handle, tcpdns_stop_cb);
} else if (uv_is_closing(&sock->uv_handle.handle)) {
tcpdns_close_sock(sock);
} else {
uv_close(&sock->uv_handle.handle, tcpdns_close_cb);
}
@@ -1271,6 +1294,7 @@ tcpdns_close_direct(isc_nmsocket_t *sock) {
isc__nmsocket_timer_stop(sock);
isc__nm_stop_reading(sock);
uv_close((uv_handle_t *)&sock->timer, timer_close_cb);
}
@@ -1313,6 +1337,19 @@ isc__nm_async_tcpdnsclose(isc__networker_t *worker, isc__netievent_t *ev0) {
tcpdns_close_direct(sock);
}
static void
tcpdns_close_connect_cb(uv_handle_t *handle) {
isc_nmsocket_t *sock = uv_handle_get_data(handle);
REQUIRE(VALID_NMSOCK(sock));
REQUIRE(isc__nm_in_netthread());
REQUIRE(sock->tid == isc_nm_tid());
isc__nmsocket_prep_destroy(sock);
isc__nmsocket_detach(&sock);
}
void
isc__nm_tcpdns_shutdown(isc_nmsocket_t *sock) {
REQUIRE(VALID_NMSOCK(sock));
@@ -1327,7 +1364,14 @@ isc__nm_tcpdns_shutdown(isc_nmsocket_t *sock) {
return;
}
if (atomic_load(&sock->connecting) || sock->accepting) {
if (sock->accepting) {
return;
}
if (atomic_load(&sock->connecting)) {
isc_nmsocket_t *tsock = NULL;
isc__nmsocket_attach(sock, &tsock);
uv_close(&sock->uv_handle.handle, tcpdns_close_connect_cb);
return;
}