2 * libwebsockets - small server side websockets and web server implementation
4 * Copyright (C) 2010-2015 Andy Green <andy@warmcat.com>
6 * This library is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU Lesser General Public
8 * License as published by the Free Software Foundation:
9 * version 2.1 of the License.
11 * This library is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 * Lesser General Public License for more details.
16 * You should have received a copy of the GNU Lesser General Public
17 * License along with this library; if not, write to the Free Software
18 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
22 #include "private-libwebsockets.h"
25 lws_calllback_as_writeable(struct lws *wsi)
31 n = LWS_CALLBACK_CLIENT_WRITEABLE;
33 case LWSCM_WS_SERVING:
34 n = LWS_CALLBACK_SERVER_WRITEABLE;
37 n = LWS_CALLBACK_HTTP_WRITEABLE;
40 lwsl_debug("%s: %p (user=%p)\n", __func__, wsi, wsi->user_space);
41 return user_callback_handle_rxflow(wsi->protocol->callback,
42 wsi, (enum lws_callback_reasons) n,
43 wsi->user_space, NULL, 0);
47 lws_handle_POLLOUT_event(struct lws *wsi, struct lws_pollfd *pollfd)
49 int write_type = LWS_WRITE_PONG;
50 struct lws_tokens eff_buf;
57 * user callback is lowest priority to get these notifications
58 * actually, since other pending things cannot be disordered
61 /* Priority 1: pending truncated sends are incomplete ws fragments
62 * If anything else sent first the protocol would be
66 if (lws_issue_raw(wsi, wsi->trunc_alloc + wsi->trunc_offset,
67 wsi->trunc_len) < 0) {
68 lwsl_info("%s signalling to close\n", __func__);
71 /* leave POLLOUT active either way */
74 if (wsi->state == LWSS_FLUSHING_STORED_SEND_BEFORE_CLOSE)
75 return -1; /* retry closing now */
79 /* Priority 2: protocol packets
82 lwsl_info("servicing pps %d\n", wsi->pps);
84 case LWS_PPS_HTTP2_MY_SETTINGS:
85 case LWS_PPS_HTTP2_ACK_SETTINGS:
86 lws_http2_do_pps_send(lws_get_context(wsi), wsi);
91 wsi->pps = LWS_PPS_NONE;
92 lws_rx_flow_control(wsi, 1);
94 return 0; /* leave POLLOUT active */
97 /* Priority 3: pending control packets (pong or close)
99 if ((wsi->state == LWSS_ESTABLISHED &&
100 wsi->u.ws.ping_pending_flag) ||
101 (wsi->state == LWSS_RETURNED_CLOSE_ALREADY &&
102 wsi->u.ws.payload_is_close)) {
104 if (wsi->u.ws.payload_is_close)
105 write_type = LWS_WRITE_CLOSE;
107 n = lws_write(wsi, &wsi->u.ws.ping_payload_buf[LWS_PRE],
108 wsi->u.ws.ping_payload_len, write_type);
112 /* well he is sent, mark him done */
113 wsi->u.ws.ping_pending_flag = 0;
114 if (wsi->u.ws.payload_is_close)
115 /* oh... a close frame was it... then we are done */
118 /* otherwise for PING, leave POLLOUT active either way */
122 /* Priority 4: if we are closing, not allowed to send more data frags
123 * which means user callback or tx ext flush banned now
125 if (wsi->state == LWSS_RETURNED_CLOSE_ALREADY)
128 /* Priority 5: Tx path extension with more to send
130 * These are handled as new fragments each time around
131 * So while we must block new writeable callback to enforce
132 * payload ordering, but since they are always complete
133 * fragments control packets can interleave OK.
135 if (wsi->state == LWSS_ESTABLISHED && wsi->u.ws.tx_draining_ext) {
136 lwsl_ext("SERVICING TX EXT DRAINING\n");
137 if (lws_write(wsi, NULL, 0, LWS_WRITE_CONTINUATION) < 0)
139 /* leave POLLOUT active */
143 /* Priority 6: user can get the callback
145 m = lws_ext_cb_active(wsi, LWS_EXT_CB_IS_WRITEABLE, NULL, 0);
148 #ifndef LWS_NO_EXTENSIONS
149 if (!wsi->extension_data_pending)
153 * check in on the active extensions, see if they
154 * had pending stuff to spill... they need to get the
155 * first look-in otherwise sequence will be disordered
157 * NULL, zero-length eff_buf means just spill pending
163 /* default to nobody has more to spill */
166 eff_buf.token = NULL;
167 eff_buf.token_len = 0;
169 /* give every extension a chance to spill */
171 m = lws_ext_cb_active(wsi,
172 LWS_EXT_CB_PACKET_TX_PRESEND,
175 lwsl_err("ext reports fatal error\n");
180 * at least one extension told us he has more
181 * to spill, so we will go around again after
185 /* assuming they gave us something to send, send it */
187 if (eff_buf.token_len) {
188 n = lws_issue_raw(wsi, (unsigned char *)eff_buf.token,
191 lwsl_info("closing from POLLOUT spill\n");
195 * Keep amount spilled small to minimize chance of this
197 if (n != eff_buf.token_len) {
198 lwsl_err("Unable to spill ext %d vs %s\n",
199 eff_buf.token_len, n);
205 /* no extension has more to spill */
211 * There's more to spill from an extension, but we just sent
212 * something... did that leave the pipe choked?
215 if (!lws_send_pipe_choked(wsi))
216 /* no we could add more */
219 lwsl_info("choked in POLLOUT service\n");
222 * Yes, he's choked. Leave the POLLOUT masked on so we will
223 * come back here when he is unchoked. Don't call the user
224 * callback to enforce ordering of spilling, he'll get called
225 * when we come back here and there's nothing more to spill.
230 #ifndef LWS_NO_EXTENSIONS
231 wsi->extension_data_pending = 0;
237 if (lws_change_pollfd(wsi, LWS_POLLOUT, 0)) {
238 lwsl_info("failed at set pollfd\n");
244 * we are the 'network wsi' for potentially many muxed child wsi with
245 * no network connection of their own, who have to use us for all their
246 * network actions. So we use a round-robin scheme to share out the
247 * POLLOUT notifications to our children.
249 * But because any child could exhaust the socket's ability to take
250 * writes, we can only let one child get notified each time.
252 * In addition children may be closed / deleted / added between POLLOUT
253 * notifications, so we can't hold pointers
256 if (wsi->mode != LWSCM_HTTP2_SERVING) {
257 lwsl_info("%s: non http2\n", __func__);
261 wsi->u.http2.requested_POLLOUT = 0;
262 if (!wsi->u.http2.initialized) {
263 lwsl_info("pollout on uninitialized http2 conn\n");
267 lwsl_info("%s: doing children\n", __func__);
271 wsi2 = wsi2->u.http2.next_child_wsi;
272 lwsl_info("%s: child %p\n", __func__, wsi2);
275 if (!wsi2->u.http2.requested_POLLOUT)
277 wsi2->u.http2.requested_POLLOUT = 0;
278 if (lws_calllback_as_writeable(wsi2)) {
279 lwsl_debug("Closing POLLOUT child\n");
280 lws_close_free_wsi(wsi2, LWS_CLOSE_STATUS_NOSTATUS);
283 } while (wsi2 != NULL && !lws_send_pipe_choked(wsi));
285 lwsl_info("%s: completed\n", __func__);
290 return lws_calllback_as_writeable(wsi);
294 lws_service_timeout_check(struct lws *wsi, unsigned int sec)
296 struct lws_context_per_thread *pt = &wsi->context->pt[(int)wsi->tsi];
299 * if extensions want in on it (eg, we are a mux parent)
300 * give them a chance to service child timeouts
302 if (lws_ext_cb_active(wsi, LWS_EXT_CB_1HZ, NULL, sec) < 0)
305 if (!wsi->pending_timeout)
309 * if we went beyond the allowed time, kill the
312 if ((time_t)sec > wsi->pending_timeout_limit) {
314 lwsl_notice("wsi %p: TIMEDOUT WAITING on %d (did hdr %d, ah %p, wl %d, pfd events %d)\n",
315 (void *)wsi, wsi->pending_timeout,
316 wsi->hdr_parsing_completed, wsi->u.hdr.ah,
317 pt->ah_wait_list_length,
318 pt->fds[wsi->sock].events);
321 * Since he failed a timeout, he already had a chance to do
322 * something and was unable to... that includes situations like
323 * half closed connections. So process this "failed timeout"
324 * close as a violent death and don't try to do protocol
325 * cleanup like flush partials.
327 wsi->socket_is_permanently_unusable = 1;
328 if (wsi->mode == LWSCM_WSCL_WAITING_SSL)
329 wsi->context->protocols[0].callback(wsi,
330 LWS_CALLBACK_CLIENT_CONNECTION_ERROR,
331 wsi->user_space, NULL, 0);
332 lws_close_free_wsi(wsi, LWS_CLOSE_STATUS_NOSTATUS);
340 int lws_rxflow_cache(struct lws *wsi, unsigned char *buf, int n, int len)
342 /* his RX is flowcontrolled, don't send remaining now */
343 if (wsi->rxflow_buffer) {
344 /* rxflow while we were spilling prev rxflow */
345 lwsl_info("stalling in existing rxflow buf\n");
349 /* a new rxflow, buffer it and warn caller */
350 lwsl_info("new rxflow input buffer len %d\n", len - n);
351 wsi->rxflow_buffer = lws_malloc(len - n);
352 if (!wsi->rxflow_buffer)
354 wsi->rxflow_len = len - n;
356 memcpy(wsi->rxflow_buffer, buf + n, len - n);
361 /* this is used by the platform service code to stop us waiting for network
362 * activity in poll() when we have something that already needs service
366 lws_service_adjust_timeout(struct lws_context *context, int timeout_ms, int tsi)
368 struct lws_context_per_thread *pt = &context->pt[tsi];
371 /* Figure out if we really want to wait in poll()
372 * We only need to wait if really nothing already to do and we have
373 * to wait for something from network
376 /* 1) if we know we are draining rx ext, do not wait in poll */
377 if (pt->rx_draining_ext_list)
380 #ifdef LWS_OPENSSL_SUPPORT
381 /* 2) if we know we have non-network pending data, do not wait in poll */
382 if (lws_ssl_anybody_has_buffered_read_tsi(context, tsi)) {
383 lwsl_info("ssl buffered read\n");
388 /* 3) if any ah has pending rx, do not wait in poll */
389 for (n = 0; n < context->max_http_header_pool; n++)
390 if (pt->ah_pool[n].rxpos != pt->ah_pool[n].rxlen) {
391 /* any ah with pending rx must be attached to someone */
392 assert(pt->ah_pool[n].wsi);
400 * guys that need POLLIN service again without waiting for network action
401 * can force POLLIN here if not flowcontrolled, so they will get service.
403 * Return nonzero if anybody got their POLLIN faked
406 lws_service_flag_pending(struct lws_context *context, int tsi)
408 struct lws_context_per_thread *pt = &context->pt[tsi];
409 #ifdef LWS_OPENSSL_SUPPORT
410 struct lws *wsi_next;
419 * 1) For all guys with already-available ext data to drain, if they are
420 * not flowcontrolled, fake their POLLIN status
422 wsi = pt->rx_draining_ext_list;
424 pt->fds[wsi->position_in_fds_table].revents |=
425 pt->fds[wsi->position_in_fds_table].events & LWS_POLLIN;
426 if (pt->fds[wsi->position_in_fds_table].revents &
429 wsi = wsi->u.ws.rx_draining_ext_list;
432 #ifdef LWS_OPENSSL_SUPPORT
434 * 2) For all guys with buffered SSL read data already saved up, if they
435 * are not flowcontrolled, fake their POLLIN status so they'll get
436 * service to use up the buffered incoming data, even though their
437 * network socket may have nothing
439 wsi = pt->pending_read_list;
441 wsi_next = wsi->pending_read_list_next;
442 pt->fds[wsi->position_in_fds_table].revents |=
443 pt->fds[wsi->position_in_fds_table].events & LWS_POLLIN;
444 if (pt->fds[wsi->position_in_fds_table].revents & LWS_POLLIN) {
447 * he's going to get serviced now, take him off the
448 * list of guys with buffered SSL. If he still has some
449 * at the end of the service, he'll get put back on the
452 lws_ssl_remove_wsi_from_buffered_list(wsi);
459 * 3) For any wsi who have an ah with pending RX who did not
460 * complete their current headers, and are not flowcontrolled,
461 * fake their POLLIN status so they will be able to drain the
462 * rx buffered in the ah
464 for (n = 0; n < context->max_http_header_pool; n++)
465 if (pt->ah_pool[n].rxpos != pt->ah_pool[n].rxlen &&
466 !pt->ah_pool[n].wsi->hdr_parsing_completed) {
467 pt->fds[pt->ah_pool[n].wsi->position_in_fds_table].revents |=
468 pt->fds[pt->ah_pool[n].wsi->position_in_fds_table].events &
470 if (pt->fds[pt->ah_pool[n].wsi->position_in_fds_table].revents &
479 * lws_service_fd() - Service polled socket with something waiting
480 * @context: Websocket context
481 * @pollfd: The pollfd entry describing the socket fd and which events
484 * This function takes a pollfd that has POLLIN or POLLOUT activity and
485 * services it according to the state of the associated
488 * The one call deals with all "service" that might happen on a socket
489 * including listen accepts, http files as well as websocket protocol.
491 * If a pollfd says it has something, you can just pass it to
492 * lws_service_fd() whether it is a socket handled by lws or not.
493 * If it sees it is a lws socket, the traffic will be handled and
494 * pollfd->revents will be zeroed now.
496 * If the socket is foreign to lws, it leaves revents alone. So you can
497 * see if you should service yourself by checking the pollfd revents
498 * after letting lws try to service it.
502 lws_service_fd_tsi(struct lws_context *context, struct lws_pollfd *pollfd, int tsi)
504 struct lws_context_per_thread *pt = &context->pt[tsi];
505 lws_sockfd_type our_fd = 0, tmp_fd;
506 struct lws_tokens eff_buf;
507 unsigned int pending = 0;
508 struct lws *wsi, *wsi1;
509 char draining_flow = 0;
516 * you can call us with pollfd = NULL to just allow the once-per-second
517 * global timeout checks; if less than a second since the last check
518 * it returns immediately then.
523 /* TODO: if using libev, we should probably use timeout watchers... */
524 if (context->last_timeout_check_s != now) {
525 context->last_timeout_check_s = now;
527 lws_plat_service_periodic(context);
529 /* global timeout check once per second */
534 wsi = context->pt[tsi].timeout_list;
536 /* we have to take copies, because he may be deleted */
537 wsi1 = wsi->timeout_list;
539 if (lws_service_timeout_check(wsi, (unsigned int)now)) {
540 /* he did time out... */
541 if (tmp_fd == our_fd)
542 /* it was the guy we came to service! */
544 /* he's gone, no need to mark as handled */
552 for (n = 0; n < context->count_threads; n++)
553 p += sprintf(p, " %7lu (%5d), ",
554 context->pt[n].count_conns,
555 context->pt[n].fds_count);
557 lwsl_notice("load: %s\n", s);
562 /* the socket we came to service timed out, nothing to do */
566 /* just here for timeout management? */
570 /* no, here to service a socket descriptor */
571 wsi = wsi_from_fd(context, pollfd->fd);
573 /* not lws connection ... leave revents alone and return */
577 * so that caller can tell we handled, past here we need to
578 * zero down pollfd->revents after handling
583 /* handle session socket closed */
585 if ((!(pollfd->revents & pollfd->events & LWS_POLLIN)) &&
586 (pollfd->revents & LWS_POLLHUP)) {
587 wsi->socket_is_permanently_unusable = 1;
588 lwsl_debug("Session Socket %p (fd=%d) dead\n",
589 (void *)wsi, pollfd->fd);
591 goto close_and_handled;
595 if (pollfd->revents & LWS_POLLOUT)
596 wsi->sock_send_blocking = FALSE;
601 /* okay, what we came here to do... */
604 case LWSCM_HTTP_SERVING:
605 case LWSCM_HTTP_SERVING_ACCEPTED:
606 case LWSCM_SERVER_LISTENER:
607 case LWSCM_SSL_ACK_PENDING:
608 n = lws_server_socket_service(context, wsi, pollfd);
609 if (n) /* closed by above */
613 case LWSCM_WS_SERVING:
614 case LWSCM_WS_CLIENT:
615 case LWSCM_HTTP2_SERVING:
617 /* 1: something requested a callback when it was OK to write */
619 if ((pollfd->revents & LWS_POLLOUT) &&
620 (wsi->state == LWSS_ESTABLISHED ||
621 wsi->state == LWSS_HTTP2_ESTABLISHED ||
622 wsi->state == LWSS_HTTP2_ESTABLISHED_PRE_SETTINGS ||
623 wsi->state == LWSS_RETURNED_CLOSE_ALREADY ||
624 wsi->state == LWSS_FLUSHING_STORED_SEND_BEFORE_CLOSE) &&
625 lws_handle_POLLOUT_event(wsi, pollfd)) {
626 if (wsi->state == LWSS_RETURNED_CLOSE_ALREADY)
627 wsi->state = LWSS_FLUSHING_STORED_SEND_BEFORE_CLOSE;
628 lwsl_info("lws_service_fd: closing\n");
629 goto close_and_handled;
632 if (wsi->state == LWSS_RETURNED_CLOSE_ALREADY ||
633 wsi->state == LWSS_AWAITING_CLOSE_ACK) {
635 * we stopped caring about anything except control
636 * packets. Force flow control off, defeat tx
639 lws_rx_flow_control(wsi, 1);
640 wsi->u.ws.tx_draining_ext = 0;
643 if (wsi->u.ws.tx_draining_ext) {
644 /* we cannot deal with new RX until the TX ext
645 * path has been drained. It's because new
646 * rx will, eg, crap on the wsi rx buf that
647 * may be needed to retain state.
649 * TX ext drain path MUST go through event loop
655 if (!(wsi->rxflow_change_to & LWS_RXFLOW_ALLOW))
656 /* We cannot deal with any kind of new RX
657 * because we are RX-flowcontrolled.
661 /* 2: RX Extension needs to be drained
664 if (wsi->state == LWSS_ESTABLISHED &&
665 wsi->u.ws.rx_draining_ext) {
667 lwsl_ext("%s: RX EXT DRAINING: Service\n", __func__);
668 #ifndef LWS_NO_CLIENT
669 if (wsi->mode == LWSCM_WS_CLIENT) {
670 n = lws_client_rx_sm(wsi, 0);
676 n = lws_rx_sm(wsi, 0);
681 if (wsi->u.ws.rx_draining_ext)
683 * We have RX EXT content to drain, but can't do it
684 * right now. That means we cannot do anything lower
689 /* 3: RX Flowcontrol buffer needs to be drained
692 if (wsi->rxflow_buffer) {
693 lwsl_info("draining rxflow (len %d)\n",
694 wsi->rxflow_len - wsi->rxflow_pos
697 eff_buf.token = (char *)wsi->rxflow_buffer +
699 eff_buf.token_len = wsi->rxflow_len - wsi->rxflow_pos;
704 /* 4: any incoming (or ah-stashed incoming rx) data ready?
705 * notice if rx flow going off raced poll(), rx flow wins
708 if (!(pollfd->revents & pollfd->events & LWS_POLLIN))
712 /* all the union members start with hdr, so even in ws mode
713 * we can deal with the ah via u.hdr
716 lwsl_err("%s: %p: using inherited ah rx\n", __func__, wsi);
717 eff_buf.token_len = wsi->u.hdr.ah->rxlen -
718 wsi->u.hdr.ah->rxpos;
719 eff_buf.token = (char *)wsi->u.hdr.ah->rx +
720 wsi->u.hdr.ah->rxpos;
723 eff_buf.token_len = lws_ssl_capable_read(wsi, pt->serv_buf,
724 pending ? pending : LWS_MAX_SOCKET_IO_BUF);
725 switch (eff_buf.token_len) {
727 lwsl_info("service_fd: closing due to 0 length read\n");
728 goto close_and_handled;
729 case LWS_SSL_CAPABLE_MORE_SERVICE:
730 lwsl_info("SSL Capable more service\n");
733 case LWS_SSL_CAPABLE_ERROR:
734 lwsl_info("Closing when error\n");
735 goto close_and_handled;
738 eff_buf.token = (char *)pt->serv_buf;
741 * give any active extensions a chance to munge the buffer
742 * before parse. We pass in a pointer to an lws_tokens struct
743 * prepared with the default buffer and content length that's in
744 * there. Rather than rewrite the default buffer, extensions
745 * that expect to grow the buffer can adapt .token to
746 * point to their own per-connection buffer in the extension
747 * user allocation. By default with no extensions or no
748 * extension callback handling, just the normal input buffer is
749 * used then so it is efficient.
755 m = lws_ext_cb_active(wsi, LWS_EXT_CB_PACKET_RX_PREPARSE,
758 goto close_and_handled;
762 /* service incoming data */
764 if (eff_buf.token_len) {
766 * if draining from rxflow buffer, not
767 * critical to track what was used since at the
768 * use it bumps wsi->rxflow_pos. If we come
769 * around again it will pick up from where it
772 n = lws_read(wsi, (unsigned char *)eff_buf.token,
781 eff_buf.token = NULL;
782 eff_buf.token_len = 0;
786 lwsl_err("%s: %p: detaching inherited used ah\n", __func__, wsi);
787 /* show we used all the pending rx up */
788 wsi->u.hdr.ah->rxpos = wsi->u.hdr.ah->rxlen;
789 /* we can run the normal ah detach flow despite
790 * being in ws union mode, since all union members
792 lws_header_table_detach(wsi);
795 pending = lws_ssl_pending(wsi);
797 pending = pending > LWS_MAX_SOCKET_IO_BUF ?
798 LWS_MAX_SOCKET_IO_BUF : pending;
802 if (draining_flow && wsi->rxflow_buffer &&
803 wsi->rxflow_pos == wsi->rxflow_len) {
804 lwsl_info("flow buffer: drained\n");
805 lws_free_set_NULL(wsi->rxflow_buffer);
806 /* having drained the rxflow buffer, can rearm POLLIN */
810 _lws_rx_flow_control(wsi);
811 /* n ignored, needed for NO_SERVER case */
820 n = lws_client_socket_service(context, wsi, pollfd);
831 lwsl_debug("Close and handled\n");
832 lws_close_free_wsi(wsi, LWS_CLOSE_STATUS_NOSTATUS);
834 * pollfd may point to something else after the close
835 * due to pollfd swapping scheme on delete on some platforms
836 * we can't clear revents now because it'd be the wrong guy's revents
846 lws_service_fd(struct lws_context *context, struct lws_pollfd *pollfd)
848 return lws_service_fd_tsi(context, pollfd, 0);
852 * lws_service() - Service any pending websocket activity
853 * @context: Websocket context
854 * @timeout_ms: Timeout for poll; 0 means return immediately if nothing needed
855 * service otherwise block and service immediately, returning
856 * after the timeout if nothing needed service.
858 * This function deals with any pending websocket traffic, for three
859 * kinds of event. It handles these events on both server and client
860 * types of connection the same.
862 * 1) Accept new connections to our context's server
864 * 2) Call the receive callback for incoming frame data received by
865 * server or client connections.
867 * You need to call this service function periodically to all the above
868 * functions to happen; if your application is single-threaded you can
869 * just call it in your main event loop.
871 * Alternatively you can fork a new process that asynchronously handles
872 * calling this service in a loop. In that case you are happy if this
873 * call blocks your thread until it needs to take care of something and
874 * would call it with a large nonzero timeout. Your loop then takes no
875 * CPU while there is nothing happening.
877 * If you are calling it in a single-threaded app, you don't want it to
878 * wait around blocking other things in your loop from happening, so you
879 * would call it with a timeout_ms of 0, so it returns immediately if
880 * nothing is pending, or as soon as it services whatever was pending.
884 lws_service(struct lws_context *context, int timeout_ms)
886 return lws_plat_service(context, timeout_ms);
890 lws_service_tsi(struct lws_context *context, int timeout_ms, int tsi)
892 return lws_plat_service_tsi(context, timeout_ms, tsi);