int
lws_handle_POLLOUT_event(struct lws *wsi, struct lws_pollfd *pollfd)
{
int write_type = LWS_WRITE_PONG;
struct lws_tokens eff_buf;
#ifdef LWS_USE_HTTP2
struct lws *wsi2;
#endif
int ret, m, n;
/*
* user callback is lowest priority to get these notifications
* actually, since other pending things cannot be disordered
*/
/* Priority 1: pending truncated sends are incomplete ws fragments
* If anything else sent first the protocol would be
* corrupted.
*/
if (wsi->trunc_len) {
if (lws_issue_raw(wsi, wsi->trunc_alloc + wsi->trunc_offset,
wsi->trunc_len) < 0) {
lwsl_info("%s signalling to close\n", __func__);
return -1;
}
/* leave POLLOUT active either way */
return 0;
} else
if (wsi->state == LWSS_FLUSHING_STORED_SEND_BEFORE_CLOSE)
return -1; /* retry closing now */
#ifdef LWS_USE_HTTP2
/* Priority 2: protocol packets
*/
if (wsi->pps) {
lwsl_info("servicing pps %d\n", wsi->pps);
switch (wsi->pps) {
case LWS_PPS_HTTP2_MY_SETTINGS:
case LWS_PPS_HTTP2_ACK_SETTINGS:
lws_http2_do_pps_send(lws_get_context(wsi), wsi);
break;
default:
break;
}
wsi->pps = LWS_PPS_NONE;
lws_rx_flow_control(wsi, 1);
return 0; /* leave POLLOUT active */
}
#endif
/* Priority 3: pending control packets (pong or close)
*/
if ((wsi->state == LWSS_ESTABLISHED &&
wsi->u.ws.ping_pending_flag) ||
(wsi->state == LWSS_RETURNED_CLOSE_ALREADY &&
wsi->u.ws.payload_is_close)) {
if (wsi->u.ws.payload_is_close)
write_type = LWS_WRITE_CLOSE;
n = lws_write(wsi, &wsi->u.ws.ping_payload_buf[LWS_PRE],
wsi->u.ws.ping_payload_len, write_type);
if (n < 0)
return -1;
/* well he is sent, mark him done */
wsi->u.ws.ping_pending_flag = 0;
if (wsi->u.ws.payload_is_close)
/* oh... a close frame was it... then we are done */
return -1;
/* otherwise for PING, leave POLLOUT active either way */
return 0;
}
/* Priority 4: if we are closing, not allowed to send more data frags
* which means user callback or tx ext flush banned now
*/
if (wsi->state == LWSS_RETURNED_CLOSE_ALREADY)
goto user_service;
/* Priority 5: Tx path extension with more to send
*
* These are handled as new fragments each time around
* So while we must block new writeable callback to enforce
* payload ordering, but since they are always complete
* fragments control packets can interleave OK.
*/
if (wsi->state == LWSS_ESTABLISHED && wsi->u.ws.tx_draining_ext) {
lwsl_ext("SERVICING TX EXT DRAINING\n");
if (lws_write(wsi, NULL, 0, LWS_WRITE_CONTINUATION) < 0)
return -1;
/* leave POLLOUT active */
return 0;
}
/* Priority 6: user can get the callback
*/
m = lws_ext_cb_active(wsi, LWS_EXT_CB_IS_WRITEABLE, NULL, 0);
#ifndef LWS_NO_EXTENSIONS
if (!wsi->extension_data_pending)
goto user_service;
#endif
/*
* check in on the active extensions, see if they
* had pending stuff to spill... they need to get the
* first look-in otherwise sequence will be disordered
*
* NULL, zero-length eff_buf means just spill pending
*/
ret = 1;
while (ret == 1) {
/* default to nobody has more to spill */
ret = 0;
eff_buf.token = NULL;
eff_buf.token_len = 0;
/* give every extension a chance to spill */
m = lws_ext_cb_active(wsi,
LWS_EXT_CB_PACKET_TX_PRESEND,
&eff_buf, 0);
if (m < 0) {
lwsl_err("ext reports fatal error\n");
return -1;
}
if (m)
/*
* at least one extension told us he has more
* to spill, so we will go around again after
*/
ret = 1;
/* assuming they gave us something to send, send it */
if (eff_buf.token_len) {
n = lws_issue_raw(wsi, (unsigned char *)eff_buf.token,
eff_buf.token_len);
if (n < 0) {
lwsl_info("closing from POLLOUT spill\n");
return -1;
}
/*
* Keep amount spilled small to minimize chance of this
*/
if (n != eff_buf.token_len) {
lwsl_err("Unable to spill ext %d vs %s\n",
eff_buf.token_len, n);
return -1;
}
} else
continue;
/* no extension has more to spill */
if (!ret)
continue;
/*
* There's more to spill from an extension, but we just sent
* something... did that leave the pipe choked?
*/
if (!lws_send_pipe_choked(wsi))
/* no we could add more */
continue;
lwsl_info("choked in POLLOUT service\n");
/*
* Yes, he's choked. Leave the POLLOUT masked on so we will
* come back here when he is unchoked. Don't call the user
* callback to enforce ordering of spilling, he'll get called
* when we come back here and there's nothing more to spill.
*/
return 0;
}
#ifndef LWS_NO_EXTENSIONS
wsi->extension_data_pending = 0;
#endif
user_service:
/* one shot */
if (pollfd) {
if (lws_change_pollfd(wsi, LWS_POLLOUT, 0)) {
lwsl_info("failed at set pollfd\n");
return 1;
}
lws_libev_io(wsi, LWS_EV_STOP | LWS_EV_WRITE);
}
#ifdef LWS_USE_HTTP2
/*
* we are the 'network wsi' for potentially many muxed child wsi with
* no network connection of their own, who have to use us for all their
* network actions. So we use a round-robin scheme to share out the
* POLLOUT notifications to our children.
*
* But because any child could exhaust the socket's ability to take
* writes, we can only let one child get notified each time.
*
* In addition children may be closed / deleted / added between POLLOUT
* notifications, so we can't hold pointers
*/
if (wsi->mode != LWSCM_HTTP2_SERVING) {
lwsl_info("%s: non http2\n", __func__);
goto notify;
}
wsi->u.http2.requested_POLLOUT = 0;
if (!wsi->u.http2.initialized) {
lwsl_info("pollout on uninitialized http2 conn\n");
return 0;
}
lwsl_info("%s: doing children\n", __func__);
wsi2 = wsi;
do {
wsi2 = wsi2->u.http2.next_child_wsi;
lwsl_info("%s: child %p\n", __func__, wsi2);
if (!wsi2)
continue;
if (!wsi2->u.http2.requested_POLLOUT)
continue;
wsi2->u.http2.requested_POLLOUT = 0;
if (lws_calllback_as_writeable(wsi2)) {
lwsl_debug("Closing POLLOUT child\n");
lws_close_free_wsi(wsi2, LWS_CLOSE_STATUS_NOSTATUS);
}
wsi2 = wsi;
} while (wsi2 != NULL && !lws_send_pipe_choked(wsi));
lwsl_info("%s: completed\n", __func__);
return 0;
notify:
#endif
return lws_calllback_as_writeable(wsi);
}
int
lws_handle_POLLOUT_event(struct libwebsocket_context *context,
struct libwebsocket *wsi, struct libwebsocket_pollfd *pollfd)
{
int n;
struct lws_tokens eff_buf;
#ifdef LWS_USE_HTTP2
struct libwebsocket *wsi2;
#endif
int ret;
int m;
int handled = 0;
/* pending truncated sends have uber priority */
if (wsi->truncated_send_len) {
if (lws_issue_raw(wsi, wsi->truncated_send_malloc +
wsi->truncated_send_offset,
wsi->truncated_send_len) < 0) {
lwsl_info("lws_handle_POLLOUT_event signalling to close\n");
return -1;
}
/* leave POLLOUT active either way */
return 0;
} else
if (wsi->state == WSI_STATE_FLUSHING_STORED_SEND_BEFORE_CLOSE) {
lwsl_info("***** %x signalling to close in POLLOUT handler\n", wsi);
return -1; /* retry closing now */
}
#ifdef LWS_USE_HTTP2
/* protocol packets are next */
if (wsi->pps) {
lwsl_info("servicing pps %d\n", wsi->pps);
switch (wsi->pps) {
case LWS_PPS_HTTP2_MY_SETTINGS:
case LWS_PPS_HTTP2_ACK_SETTINGS:
lws_http2_do_pps_send(context, wsi);
break;
default:
break;
}
wsi->pps = LWS_PPS_NONE;
libwebsocket_rx_flow_control(wsi, 1);
return 0; /* leave POLLOUT active */
}
#endif
/* pending control packets have next priority */
if (wsi->state == WSI_STATE_ESTABLISHED && wsi->u.ws.ping_payload_len) {
n = libwebsocket_write(wsi,
&wsi->u.ws.ping_payload_buf[
LWS_SEND_BUFFER_PRE_PADDING],
wsi->u.ws.ping_payload_len,
LWS_WRITE_PONG);
if (n < 0)
return -1;
/* well he is sent, mark him done */
wsi->u.ws.ping_payload_len = 0;
/* leave POLLOUT active either way */
return 0;
}
/* if nothing critical, user can get the callback */
m = lws_ext_callback_for_each_active(wsi, LWS_EXT_CALLBACK_IS_WRITEABLE,
NULL, 0);
#ifndef LWS_NO_EXTENSIONS
if (!wsi->extension_data_pending || handled == 2)
goto user_service;
#endif
/*
* check in on the active extensions, see if they
* had pending stuff to spill... they need to get the
* first look-in otherwise sequence will be disordered
*
* NULL, zero-length eff_buf means just spill pending
*/
ret = 1;
while (ret == 1) {
/* default to nobody has more to spill */
ret = 0;
eff_buf.token = NULL;
eff_buf.token_len = 0;
/* give every extension a chance to spill */
m = lws_ext_callback_for_each_active(wsi,
LWS_EXT_CALLBACK_PACKET_TX_PRESEND,
&eff_buf, 0);
if (m < 0) {
lwsl_err("ext reports fatal error\n");
return -1;
}
if (m)
/*
* at least one extension told us he has more
* to spill, so we will go around again after
*/
ret = 1;
/* assuming they gave us something to send, send it */
if (eff_buf.token_len) {
n = lws_issue_raw(wsi, (unsigned char *)eff_buf.token,
eff_buf.token_len);
if (n < 0) {
lwsl_info("closing from POLLOUT spill\n");
return -1;
}
/*
* Keep amount spilled small to minimize chance of this
*/
if (n != eff_buf.token_len) {
lwsl_err("Unable to spill ext %d vs %s\n",
eff_buf.token_len, n);
return -1;
}
} else
continue;
/* no extension has more to spill */
if (!ret)
continue;
/*
* There's more to spill from an extension, but we just sent
* something... did that leave the pipe choked?
*/
if (!lws_send_pipe_choked(wsi))
/* no we could add more */
continue;
lwsl_info("choked in POLLOUT service\n");
/*
* Yes, he's choked. Leave the POLLOUT masked on so we will
* come back here when he is unchoked. Don't call the user
* callback to enforce ordering of spilling, he'll get called
* when we come back here and there's nothing more to spill.
*/
return 0;
}
#ifndef LWS_NO_EXTENSIONS
wsi->extension_data_pending = 0;
user_service:
#endif
/* one shot */
if (pollfd) {
if (lws_change_pollfd(wsi, LWS_POLLOUT, 0)) {
lwsl_info("failled at set pollfd\n");
return 1;
}
lws_libev_io(context, wsi, LWS_EV_STOP | LWS_EV_WRITE);
}
#ifdef LWS_USE_HTTP2
/*
* we are the 'network wsi' for potentially many muxed child wsi with
* no network connection of their own, who have to use us for all their
* network actions. So we use a round-robin scheme to share out the
* POLLOUT notifications to our children.
*
* But because any child could exhaust the socket's ability to take
* writes, we can only let one child get notified each time.
*
* In addition children may be closed / deleted / added between POLLOUT
* notifications, so we can't hold pointers
*/
if (wsi->mode != LWS_CONNMODE_HTTP2_SERVING) {
lwsl_info("%s: non http2\n", __func__);
goto notify;
}
wsi->u.http2.requested_POLLOUT = 0;
if (!wsi->u.http2.initialized) {
lwsl_info("pollout on uninitialized http2 conn\n");
return 0;
}
lwsl_info("%s: doing children\n", __func__);
wsi2 = wsi;
do {
wsi2 = wsi2->u.http2.next_child_wsi;
lwsl_info("%s: child %p\n", __func__, wsi2);
if (!wsi2)
continue;
if (!wsi2->u.http2.requested_POLLOUT)
continue;
wsi2->u.http2.requested_POLLOUT = 0;
if (lws_calllback_as_writeable(context, wsi2)) {
lwsl_debug("Closing POLLOUT child\n");
libwebsocket_close_and_free_session(context, wsi2,
LWS_CLOSE_STATUS_NOSTATUS);
}
wsi2 = wsi;
} while (wsi2 != NULL && !lws_send_pipe_choked(wsi));
lwsl_info("%s: completed\n", __func__);
return 0;
notify:
#endif
return lws_calllback_as_writeable(context, wsi);
}