lib/service.c

   1 /*
   2  * libwebsockets - small server side websockets and web server implementation
   3  *
   4  * Copyright (C) 2010-2015 Andy Green <andy@warmcat.com>
   5  *
   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.
  10  *
  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.
  15  *
  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,
  19  *  MA  02110-1301  USA
  20  */
  21
  22 #include "private-libwebsockets.h"
  23
  24 static int
  25 lws_calllback_as_writeable(struct lws *wsi)
  26 {
  27         int n;
  28
  29         switch (wsi->mode) {
  30         case LWSCM_WS_CLIENT:
  31                 n = LWS_CALLBACK_CLIENT_WRITEABLE;
  32                 break;
  33         case LWSCM_WS_SERVING:
  34                 n = LWS_CALLBACK_SERVER_WRITEABLE;
  35                 break;
  36         default:
  37                 n = LWS_CALLBACK_HTTP_WRITEABLE;
  38                 break;
  39         }
  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);
  44 }
  45
  46 int
  47 lws_handle_POLLOUT_event(struct lws *wsi, struct lws_pollfd *pollfd)
  48 {
  49         int write_type = LWS_WRITE_PONG;
  50         struct lws_tokens eff_buf;
  51 #ifdef LWS_USE_HTTP2
  52         struct lws *wsi2;
  53 #endif
  54         int ret, m, n;
  55
  56         //lwsl_err("%s: %p\n", __func__, wsi);
  57
  58         /*
  59          * user callback is lowest priority to get these notifications
  60          * actually, since other pending things cannot be disordered
  61          */
  62
  63         /* Priority 1: pending truncated sends are incomplete ws fragments
  64          *             If anything else sent first the protocol would be
  65          *             corrupted.
  66          */
  67         if (wsi->trunc_len) {
  68                 if (lws_issue_raw(wsi, wsi->trunc_alloc + wsi->trunc_offset,
  69                                   wsi->trunc_len) < 0) {
  70                         lwsl_info("%s signalling to close\n", __func__);
  71                         return -1;
  72                 }
  73                 /* leave POLLOUT active either way */
  74                 return 0;
  75         } else
  76                 if (wsi->state == LWSS_FLUSHING_STORED_SEND_BEFORE_CLOSE)
  77                         return -1; /* retry closing now */
  78
  79
  80 #ifdef LWS_USE_HTTP2
  81         /* Priority 2: protocol packets
  82          */
  83         if (wsi->pps) {
  84                 lwsl_info("servicing pps %d\n", wsi->pps);
  85                 switch (wsi->pps) {
  86                 case LWS_PPS_HTTP2_MY_SETTINGS:
  87                 case LWS_PPS_HTTP2_ACK_SETTINGS:
  88                         lws_http2_do_pps_send(lws_get_context(wsi), wsi);
  89                         break;
  90                 default:
  91                         break;
  92                 }
  93                 wsi->pps = LWS_PPS_NONE;
  94                 lws_rx_flow_control(wsi, 1);
  95
  96                 return 0; /* leave POLLOUT active */
  97         }
  98 #endif
  99
 100 #ifdef LWS_WITH_CGI
 101         if (wsi->cgi)
 102                 goto user_service_go_again;
 103 #endif
 104
 105         /* Priority 3: pending control packets (pong or close)
 106          */
 107         if ((wsi->state == LWSS_ESTABLISHED &&
 108              wsi->u.ws.ping_pending_flag) ||
 109             (wsi->state == LWSS_RETURNED_CLOSE_ALREADY &&
 110              wsi->u.ws.payload_is_close)) {
 111
 112                 if (wsi->u.ws.payload_is_close)
 113                         write_type = LWS_WRITE_CLOSE;
 114
 115                 n = lws_write(wsi, &wsi->u.ws.ping_payload_buf[LWS_PRE],
 116                               wsi->u.ws.ping_payload_len, write_type);
 117                 if (n < 0)
 118                         return -1;
 119
 120                 /* well he is sent, mark him done */
 121                 wsi->u.ws.ping_pending_flag = 0;
 122                 if (wsi->u.ws.payload_is_close)
 123                         /* oh... a close frame was it... then we are done */
 124                         return -1;
 125
 126                 /* otherwise for PING, leave POLLOUT active either way */
 127                 return 0;
 128         }
 129
 130         /* Priority 4: if we are closing, not allowed to send more data frags
 131          *             which means user callback or tx ext flush banned now
 132          */
 133         if (wsi->state == LWSS_RETURNED_CLOSE_ALREADY)
 134                 goto user_service;
 135
 136         /* Priority 5: Tx path extension with more to send
 137          *
 138          *             These are handled as new fragments each time around
 139          *             So while we must block new writeable callback to enforce
 140          *             payload ordering, but since they are always complete
 141          *             fragments control packets can interleave OK.
 142          */
 143         if (wsi->state == LWSS_ESTABLISHED && wsi->u.ws.tx_draining_ext) {
 144                 lwsl_ext("SERVICING TX EXT DRAINING\n");
 145                 if (lws_write(wsi, NULL, 0, LWS_WRITE_CONTINUATION) < 0)
 146                         return -1;
 147                 /* leave POLLOUT active */
 148                 return 0;
 149         }
 150
 151         /* Priority 6: user can get the callback
 152          */
 153         m = lws_ext_cb_active(wsi, LWS_EXT_CB_IS_WRITEABLE, NULL, 0);
 154         if (m)
 155                 return -1;
 156 #ifndef LWS_NO_EXTENSIONS
 157         if (!wsi->extension_data_pending)
 158                 goto user_service;
 159 #endif
 160         /*
 161          * check in on the active extensions, see if they
 162          * had pending stuff to spill... they need to get the
 163          * first look-in otherwise sequence will be disordered
 164          *
 165          * NULL, zero-length eff_buf means just spill pending
 166          */
 167
 168         ret = 1;
 169         while (ret == 1) {
 170
 171                 /* default to nobody has more to spill */
 172
 173                 ret = 0;
 174                 eff_buf.token = NULL;
 175                 eff_buf.token_len = 0;
 176
 177                 /* give every extension a chance to spill */
 178
 179                 m = lws_ext_cb_active(wsi,
 180                                         LWS_EXT_CB_PACKET_TX_PRESEND,
 181                                                &eff_buf, 0);
 182                 if (m < 0) {
 183                         lwsl_err("ext reports fatal error\n");
 184                         return -1;
 185                 }
 186                 if (m)
 187                         /*
 188                          * at least one extension told us he has more
 189                          * to spill, so we will go around again after
 190                          */
 191                         ret = 1;
 192
 193                 /* assuming they gave us something to send, send it */
 194
 195                 if (eff_buf.token_len) {
 196                         n = lws_issue_raw(wsi, (unsigned char *)eff_buf.token,
 197                                           eff_buf.token_len);
 198                         if (n < 0) {
 199                                 lwsl_info("closing from POLLOUT spill\n");
 200                                 return -1;
 201                         }
 202                         /*
 203                          * Keep amount spilled small to minimize chance of this
 204                          */
 205                         if (n != eff_buf.token_len) {
 206                                 lwsl_err("Unable to spill ext %d vs %s\n",
 207                                                           eff_buf.token_len, n);
 208                                 return -1;
 209                         }
 210                 } else
 211                         continue;
 212
 213                 /* no extension has more to spill */
 214
 215                 if (!ret)
 216                         continue;
 217
 218                 /*
 219                  * There's more to spill from an extension, but we just sent
 220                  * something... did that leave the pipe choked?
 221                  */
 222
 223                 if (!lws_send_pipe_choked(wsi))
 224                         /* no we could add more */
 225                         continue;
 226
 227                 lwsl_info("choked in POLLOUT service\n");
 228
 229                 /*
 230                  * Yes, he's choked.  Leave the POLLOUT masked on so we will
 231                  * come back here when he is unchoked.  Don't call the user
 232                  * callback to enforce ordering of spilling, he'll get called
 233                  * when we come back here and there's nothing more to spill.
 234                  */
 235
 236                 return 0;
 237         }
 238 #ifndef LWS_NO_EXTENSIONS
 239         wsi->extension_data_pending = 0;
 240 #endif
 241 user_service:
 242         /* one shot */
 243
 244         if (pollfd)
 245                 if (lws_change_pollfd(wsi, LWS_POLLOUT, 0)) {
 246                         lwsl_info("failed at set pollfd\n");
 247                         return 1;
 248                 }
 249
 250
 251         if (!wsi->hdr_parsing_completed)
 252                 return 0;
 253
 254 #ifdef LWS_WITH_CGI
 255 user_service_go_again:
 256 #endif
 257
 258 #ifdef LWS_USE_HTTP2
 259         /*
 260          * we are the 'network wsi' for potentially many muxed child wsi with
 261          * no network connection of their own, who have to use us for all their
 262          * network actions.  So we use a round-robin scheme to share out the
 263          * POLLOUT notifications to our children.
 264          *
 265          * But because any child could exhaust the socket's ability to take
 266          * writes, we can only let one child get notified each time.
 267          *
 268          * In addition children may be closed / deleted / added between POLLOUT
 269          * notifications, so we can't hold pointers
 270          */
 271
 272         if (wsi->mode != LWSCM_HTTP2_SERVING) {
 273                 lwsl_info("%s: non http2\n", __func__);
 274                 goto notify;
 275         }
 276
 277         wsi->u.http2.requested_POLLOUT = 0;
 278         if (!wsi->u.http2.initialized) {
 279                 lwsl_info("pollout on uninitialized http2 conn\n");
 280                 return 0;
 281         }
 282
 283         lwsl_info("%s: doing children\n", __func__);
 284
 285         wsi2 = wsi;
 286         do {
 287                 wsi2 = wsi2->u.http2.next_child_wsi;
 288                 lwsl_info("%s: child %p\n", __func__, wsi2);
 289                 if (!wsi2)
 290                         continue;
 291                 if (!wsi2->u.http2.requested_POLLOUT)
 292                         continue;
 293                 wsi2->u.http2.requested_POLLOUT = 0;
 294                 if (lws_calllback_as_writeable(wsi2)) {
 295                         lwsl_debug("Closing POLLOUT child\n");
 296                         lws_close_free_wsi(wsi2, LWS_CLOSE_STATUS_NOSTATUS);
 297                 }
 298                 wsi2 = wsi;
 299         } while (wsi2 != NULL && !lws_send_pipe_choked(wsi));
 300
 301         lwsl_info("%s: completed\n", __func__);
 302
 303         return 0;
 304 notify:
 305 #endif
 306         return lws_calllback_as_writeable(wsi);
 307 }
 308
 309 int
 310 lws_service_timeout_check(struct lws *wsi, unsigned int sec)
 311 {
 312         struct lws_context_per_thread *pt = &wsi->context->pt[(int)wsi->tsi];
 313
 314         /*
 315          * if extensions want in on it (eg, we are a mux parent)
 316          * give them a chance to service child timeouts
 317          */
 318         if (lws_ext_cb_active(wsi, LWS_EXT_CB_1HZ, NULL, sec) < 0)
 319                 return 0;
 320
 321         if (!wsi->pending_timeout)
 322                 return 0;
 323
 324         /*
 325          * if we went beyond the allowed time, kill the
 326          * connection
 327          */
 328         if ((time_t)sec > wsi->pending_timeout_limit) {
 329 #if LWS_POSIX
 330                 /* no need to log normal idle keepalive timeout */
 331                 if (wsi->pending_timeout != PENDING_TIMEOUT_HTTP_KEEPALIVE_IDLE)
 332                         lwsl_notice("wsi %p: TIMEDOUT WAITING on %d (did hdr %d, ah %p, wl %d, pfd events %d)\n",
 333                             (void *)wsi, wsi->pending_timeout,
 334                             wsi->hdr_parsing_completed, wsi->u.hdr.ah,
 335                             pt->ah_wait_list_length,
 336                             pt->fds[wsi->sock].events);
 337 #endif
 338                 /*
 339                  * Since he failed a timeout, he already had a chance to do
 340                  * something and was unable to... that includes situations like
 341                  * half closed connections.  So process this "failed timeout"
 342                  * close as a violent death and don't try to do protocol
 343                  * cleanup like flush partials.
 344                  */
 345                 wsi->socket_is_permanently_unusable = 1;
 346                 if (wsi->mode == LWSCM_WSCL_WAITING_SSL)
 347                         wsi->vhost->protocols[0].callback(wsi,
 348                                 LWS_CALLBACK_CLIENT_CONNECTION_ERROR,
 349                                 wsi->user_space, NULL, 0);
 350
 351                 lws_close_free_wsi(wsi, LWS_CLOSE_STATUS_NOSTATUS);
 352
 353                 return 1;
 354         }
 355
 356         return 0;
 357 }
 358
 359 int lws_rxflow_cache(struct lws *wsi, unsigned char *buf, int n, int len)
 360 {
 361         /* his RX is flowcontrolled, don't send remaining now */
 362         if (wsi->rxflow_buffer) {
 363                 /* rxflow while we were spilling prev rxflow */
 364                 lwsl_info("stalling in existing rxflow buf\n");
 365                 return 1;
 366         }
 367
 368         /* a new rxflow, buffer it and warn caller */
 369         lwsl_info("new rxflow input buffer len %d\n", len - n);
 370         wsi->rxflow_buffer = lws_malloc(len - n);
 371         wsi->rxflow_len = len - n;
 372         wsi->rxflow_pos = 0;
 373         memcpy(wsi->rxflow_buffer, buf + n, len - n);
 374
 375         return 0;
 376 }
 377
 378 /* this is used by the platform service code to stop us waiting for network
 379  * activity in poll() when we have something that already needs service
 380  */
 381
 382 int
 383 lws_service_adjust_timeout(struct lws_context *context, int timeout_ms, int tsi)
 384 {
 385         struct lws_context_per_thread *pt = &context->pt[tsi];
 386         int n;
 387
 388         /* Figure out if we really want to wait in poll()
 389          * We only need to wait if really nothing already to do and we have
 390          * to wait for something from network
 391          */
 392
 393         /* 1) if we know we are draining rx ext, do not wait in poll */
 394         if (pt->rx_draining_ext_list)
 395                 return 0;
 396
 397 #ifdef LWS_OPENSSL_SUPPORT
 398         /* 2) if we know we have non-network pending data, do not wait in poll */
 399         if (lws_ssl_anybody_has_buffered_read_tsi(context, tsi)) {
 400                 lwsl_info("ssl buffered read\n");
 401                 return 0;
 402         }
 403 #endif
 404
 405         /* 3) if any ah has pending rx, do not wait in poll */
 406         for (n = 0; n < context->max_http_header_pool; n++)
 407                 if (pt->ah_pool[n].rxpos != pt->ah_pool[n].rxlen) {
 408                         /* any ah with pending rx must be attached to someone */
 409                         assert(pt->ah_pool[n].wsi);
 410                         return 0;
 411                 }
 412
 413         return timeout_ms;
 414 }
 415
 416 /*
 417  * guys that need POLLIN service again without waiting for network action
 418  * can force POLLIN here if not flowcontrolled, so they will get service.
 419  *
 420  * Return nonzero if anybody got their POLLIN faked
 421  */
 422 int
 423 lws_service_flag_pending(struct lws_context *context, int tsi)
 424 {
 425         struct lws_context_per_thread *pt = &context->pt[tsi];
 426 #ifdef LWS_OPENSSL_SUPPORT
 427         struct lws *wsi_next;
 428 #endif
 429         struct lws *wsi;
 430         int forced = 0;
 431         int n;
 432
 433         /* POLLIN faking */
 434
 435         /*
 436          * 1) For all guys with already-available ext data to drain, if they are
 437          * not flowcontrolled, fake their POLLIN status
 438          */
 439         wsi = pt->rx_draining_ext_list;
 440         while (wsi) {
 441                 pt->fds[wsi->position_in_fds_table].revents |=
 442                         pt->fds[wsi->position_in_fds_table].events & LWS_POLLIN;
 443                 if (pt->fds[wsi->position_in_fds_table].revents &
 444                     LWS_POLLIN)
 445                         forced = 1;
 446                 wsi = wsi->u.ws.rx_draining_ext_list;
 447         }
 448
 449 #ifdef LWS_OPENSSL_SUPPORT
 450         /*
 451          * 2) For all guys with buffered SSL read data already saved up, if they
 452          * are not flowcontrolled, fake their POLLIN status so they'll get
 453          * service to use up the buffered incoming data, even though their
 454          * network socket may have nothing
 455          */
 456         wsi = pt->pending_read_list;
 457         while (wsi) {
 458                 wsi_next = wsi->pending_read_list_next;
 459                 pt->fds[wsi->position_in_fds_table].revents |=
 460                         pt->fds[wsi->position_in_fds_table].events & LWS_POLLIN;
 461                 if (pt->fds[wsi->position_in_fds_table].revents & LWS_POLLIN) {
 462                         forced = 1;
 463                         /*
 464                          * he's going to get serviced now, take him off the
 465                          * list of guys with buffered SSL.  If he still has some
 466                          * at the end of the service, he'll get put back on the
 467                          * list then.
 468                          */
 469                         lws_ssl_remove_wsi_from_buffered_list(wsi);
 470                 }
 471
 472                 wsi = wsi_next;
 473         }
 474 #endif
 475         /*
 476          * 3) For any wsi who have an ah with pending RX who did not
 477          * complete their current headers, and are not flowcontrolled,
 478          * fake their POLLIN status so they will be able to drain the
 479          * rx buffered in the ah
 480          */
 481         for (n = 0; n < context->max_http_header_pool; n++)
 482                 if (pt->ah_pool[n].rxpos != pt->ah_pool[n].rxlen &&
 483                     !pt->ah_pool[n].wsi->hdr_parsing_completed) {
 484                         pt->fds[pt->ah_pool[n].wsi->position_in_fds_table].revents |=
 485                                 pt->fds[pt->ah_pool[n].wsi->position_in_fds_table].events &
 486                                         LWS_POLLIN;
 487                         if (pt->fds[pt->ah_pool[n].wsi->position_in_fds_table].revents &
 488                             LWS_POLLIN)
 489                                 forced = 1;
 490                 }
 491
 492         return forced;
 493 }
 494
 495 #ifndef LWS_NO_CLIENT
 496
 497 LWS_VISIBLE int
 498 lws_http_client_read(struct lws *wsi, char **buf, int *len)
 499 {
 500         int rlen, n;
 501
 502
 503
 504         rlen = lws_ssl_capable_read(wsi, (unsigned char *)*buf, *len);
 505         if (rlen < 0)
 506                 return -1;
 507
 508         *len = rlen;
 509         if (rlen == 0)
 510                 return 0;
 511
 512 //      lwsl_err("%s: read %d\n", __func__, rlen);
 513
 514         /* allow the source to signal he has data again next time */
 515         wsi->client_rx_avail = 0;
 516         lws_change_pollfd(wsi, 0, LWS_POLLIN);
 517
 518         /*
 519          * server may insist on transfer-encoding: chunked,
 520          * so http client must deal with it
 521          */
 522 spin_chunks:
 523         while (wsi->chunked && (wsi->chunk_parser != ELCP_CONTENT) && *len) {
 524                 switch (wsi->chunk_parser) {
 525                 case ELCP_HEX:
 526                         if ((*buf)[0] == '\x0d') {
 527                                 wsi->chunk_parser = ELCP_CR;
 528                                 break;
 529                         }
 530                         n = char_to_hex((*buf)[0]);
 531                         if (n < 0)
 532                                 return -1;
 533                         wsi->chunk_remaining <<= 4;
 534                         wsi->chunk_remaining |= n;
 535                         break;
 536                 case ELCP_CR:
 537                         if ((*buf)[0] != '\x0a')
 538                                 return -1;
 539                         wsi->chunk_parser = ELCP_CONTENT;
 540                         lwsl_info("chunk %d\n", wsi->chunk_remaining);
 541                         if (wsi->chunk_remaining)
 542                                 break;
 543                         lwsl_info("final chunk\n");
 544                         goto completed;
 545
 546                 case ELCP_CONTENT:
 547                         break;
 548
 549                 case ELCP_POST_CR:
 550                         if ((*buf)[0] != '\x0d')
 551                                 return -1;
 552
 553                         wsi->chunk_parser = ELCP_POST_LF;
 554                         break;
 555
 556                 case ELCP_POST_LF:
 557                         if ((*buf)[0] != '\x0a')
 558                                 return -1;
 559
 560                         wsi->chunk_parser = ELCP_HEX;
 561                         wsi->chunk_remaining = 0;
 562                         break;
 563                 }
 564                 (*buf)++;
 565                 (*len)--;
 566         }
 567
 568         if (wsi->chunked && !wsi->chunk_remaining)
 569                 return 0;
 570
 571         if (wsi->u.http.content_remain &&
 572             (int)wsi->u.http.content_remain < *len)
 573                 n = wsi->u.http.content_remain;
 574         else
 575                 n = *len;
 576
 577         if (wsi->chunked && wsi->chunk_remaining &&
 578             wsi->chunk_remaining < n)
 579                 n = wsi->chunk_remaining;
 580
 581 #ifdef LWS_WITH_HTTP_PROXY
 582         /* hubbub */
 583         if (wsi->perform_rewrite)
 584                 lws_rewrite_parse(wsi->rw, (unsigned char *)*buf, n);
 585         else
 586 #endif
 587                 if (user_callback_handle_rxflow(wsi->protocol->callback,
 588                                 wsi, LWS_CALLBACK_RECEIVE_CLIENT_HTTP_READ,
 589                                 wsi->user_space, *buf, n))
 590                         return -1;
 591
 592         if (wsi->chunked && wsi->chunk_remaining) {
 593                 (*buf) += n;
 594                 wsi->chunk_remaining -= n;
 595                 *len -= n;
 596         }
 597
 598         if (wsi->chunked && !wsi->chunk_remaining)
 599                 wsi->chunk_parser = ELCP_POST_CR;
 600
 601         if (wsi->chunked && *len) {
 602                 goto spin_chunks;
 603         }
 604
 605         if (wsi->chunked)
 606                 return 0;
 607
 608         wsi->u.http.content_remain -= n;
 609         if (wsi->u.http.content_remain || !wsi->u.http.content_length)
 610                 return 0;
 611
 612 completed:
 613         if (user_callback_handle_rxflow(wsi->protocol->callback,
 614                         wsi, LWS_CALLBACK_COMPLETED_CLIENT_HTTP,
 615                         wsi->user_space, NULL, 0))
 616                 return -1;
 617
 618         if (lws_http_transaction_completed_client(wsi))
 619                 return -1;
 620
 621         return 0;
 622 }
 623 #endif
 624
 625 /**
 626  * lws_service_fd() - Service polled socket with something waiting
 627  * @context:    Websocket context
 628  * @pollfd:     The pollfd entry describing the socket fd and which events
 629  *              happened.
 630  *
 631  *      This function takes a pollfd that has POLLIN or POLLOUT activity and
 632  *      services it according to the state of the associated
 633  *      struct lws.
 634  *
 635  *      The one call deals with all "service" that might happen on a socket
 636  *      including listen accepts, http files as well as websocket protocol.
 637  *
 638  *      If a pollfd says it has something, you can just pass it to
 639  *      lws_service_fd() whether it is a socket handled by lws or not.
 640  *      If it sees it is a lws socket, the traffic will be handled and
 641  *      pollfd->revents will be zeroed now.
 642  *
 643  *      If the socket is foreign to lws, it leaves revents alone.  So you can
 644  *      see if you should service yourself by checking the pollfd revents
 645  *      after letting lws try to service it.
 646  */
 647
 648 LWS_VISIBLE int
 649 lws_service_fd_tsi(struct lws_context *context, struct lws_pollfd *pollfd, int tsi)
 650 {
 651         struct lws_context_per_thread *pt = &context->pt[tsi];
 652         lws_sockfd_type our_fd = 0, tmp_fd;
 653         struct lws_tokens eff_buf;
 654         unsigned int pending = 0;
 655         struct lws *wsi, *wsi1;
 656         char draining_flow = 0;
 657         int timed_out = 0;
 658         time_t now;
 659         int n = 0, m;
 660         int more;
 661
 662         if (!context->protocol_init_done)
 663                 lws_protocol_init(context);
 664
 665         /*
 666          * you can call us with pollfd = NULL to just allow the once-per-second
 667          * global timeout checks; if less than a second since the last check
 668          * it returns immediately then.
 669          */
 670
 671         time(&now);
 672
 673         /* TODO: if using libev, we should probably use timeout watchers... */
 674         if (context->last_timeout_check_s != now) {
 675                 context->last_timeout_check_s = now;
 676
 677                 lws_plat_service_periodic(context);
 678
 679                 /* global timeout check once per second */
 680
 681                 if (pollfd)
 682                         our_fd = pollfd->fd;
 683
 684                 wsi = context->pt[tsi].timeout_list;
 685                 while (wsi) {
 686                         /* we have to take copies, because he may be deleted */
 687                         wsi1 = wsi->timeout_list;
 688                         tmp_fd = wsi->sock;
 689                         if (lws_service_timeout_check(wsi, (unsigned int)now)) {
 690                                 /* he did time out... */
 691                                 if (tmp_fd == our_fd)
 692                                         /* it was the guy we came to service! */
 693                                         timed_out = 1;
 694                                         /* he's gone, no need to mark as handled */
 695                         }
 696                         wsi = wsi1;
 697                 }
 698 #ifdef LWS_WITH_CGI
 699                 lws_cgi_kill_terminated(pt);
 700 #endif
 701 #if 0
 702                 {
 703                         char s[300], *p = s;
 704
 705                         for (n = 0; n < context->count_threads; n++)
 706                                 p += sprintf(p, " %7lu (%5d), ",
 707                                              context->pt[n].count_conns,
 708                                              context->pt[n].fds_count);
 709
 710                         lwsl_notice("load: %s\n", s);
 711                 }
 712 #endif
 713         }
 714
 715         /* the socket we came to service timed out, nothing to do */
 716         if (timed_out)
 717                 return 0;
 718
 719         /* just here for timeout management? */
 720         if (!pollfd)
 721                 return 0;
 722
 723         /* no, here to service a socket descriptor */
 724         wsi = wsi_from_fd(context, pollfd->fd);
 725         if (!wsi)
 726                 /* not lws connection ... leave revents alone and return */
 727                 return 0;
 728
 729         /*
 730          * so that caller can tell we handled, past here we need to
 731          * zero down pollfd->revents after handling
 732          */
 733
 734 #if LWS_POSIX
 735         /* handle session socket closed */
 736
 737         if ((!(pollfd->revents & pollfd->events & LWS_POLLIN)) &&
 738             (pollfd->revents & LWS_POLLHUP)) {
 739                 wsi->socket_is_permanently_unusable = 1;
 740                 lwsl_debug("Session Socket %p (fd=%d) dead\n",
 741                                                        (void *)wsi, pollfd->fd);
 742
 743                 goto close_and_handled;
 744         }
 745
 746 #ifdef _WIN32
 747         if (pollfd->revents & LWS_POLLOUT)
 748                 wsi->sock_send_blocking = FALSE;
 749 #endif
 750
 751 #endif
 752
 753         lwsl_debug("fd=%d, revents=%d\n", pollfd->fd, pollfd->revents);
 754
 755         /* okay, what we came here to do... */
 756
 757         switch (wsi->mode) {
 758         case LWSCM_HTTP_SERVING:
 759         case LWSCM_HTTP_CLIENT:
 760         case LWSCM_HTTP_SERVING_ACCEPTED:
 761         case LWSCM_SERVER_LISTENER:
 762         case LWSCM_SSL_ACK_PENDING:
 763                 if (wsi->state == LWSS_CLIENT_HTTP_ESTABLISHED)
 764                         goto handled;
 765
 766 #ifdef LWS_WITH_CGI
 767                 if (wsi->cgi && (pollfd->revents & LWS_POLLOUT)) {
 768                         n = lws_handle_POLLOUT_event(wsi, pollfd);
 769                         if (n)
 770                                 goto close_and_handled;
 771                         goto handled;
 772                 }
 773 #endif
 774                 n = lws_server_socket_service(context, wsi, pollfd);
 775                 if (n) /* closed by above */
 776                         return 1;
 777                 goto handled;
 778
 779         case LWSCM_WS_SERVING:
 780         case LWSCM_WS_CLIENT:
 781         case LWSCM_HTTP2_SERVING:
 782         case LWSCM_HTTP_CLIENT_ACCEPTED:
 783
 784                 /* 1: something requested a callback when it was OK to write */
 785
 786                 if ((pollfd->revents & LWS_POLLOUT) &&
 787                     (wsi->state == LWSS_ESTABLISHED ||
 788                      wsi->state == LWSS_HTTP2_ESTABLISHED ||
 789                      wsi->state == LWSS_HTTP2_ESTABLISHED_PRE_SETTINGS ||
 790                      wsi->state == LWSS_RETURNED_CLOSE_ALREADY ||
 791                      wsi->state == LWSS_FLUSHING_STORED_SEND_BEFORE_CLOSE) &&
 792                     lws_handle_POLLOUT_event(wsi, pollfd)) {
 793                         if (wsi->state == LWSS_RETURNED_CLOSE_ALREADY)
 794                                 wsi->state = LWSS_FLUSHING_STORED_SEND_BEFORE_CLOSE;
 795                         lwsl_info("lws_service_fd: closing\n");
 796                         goto close_and_handled;
 797                 }
 798
 799                 if (wsi->state == LWSS_RETURNED_CLOSE_ALREADY ||
 800                     wsi->state == LWSS_AWAITING_CLOSE_ACK) {
 801                         /*
 802                          * we stopped caring about anything except control
 803                          * packets.  Force flow control off, defeat tx
 804                          * draining.
 805                          */
 806                         lws_rx_flow_control(wsi, 1);
 807                         wsi->u.ws.tx_draining_ext = 0;
 808                 }
 809
 810                 if (wsi->u.ws.tx_draining_ext)
 811                         /* we cannot deal with new RX until the TX ext
 812                          * path has been drained.  It's because new
 813                          * rx will, eg, crap on the wsi rx buf that
 814                          * may be needed to retain state.
 815                          *
 816                          * TX ext drain path MUST go through event loop
 817                          * to avoid blocking.
 818                          */
 819                         break;
 820
 821                 if (!(wsi->rxflow_change_to & LWS_RXFLOW_ALLOW))
 822                         /* We cannot deal with any kind of new RX
 823                          * because we are RX-flowcontrolled.
 824                          */
 825                         break;
 826
 827                 /* 2: RX Extension needs to be drained
 828                  */
 829
 830                 if (wsi->state == LWSS_ESTABLISHED &&
 831                     wsi->u.ws.rx_draining_ext) {
 832
 833                         lwsl_ext("%s: RX EXT DRAINING: Service\n", __func__);
 834 #ifndef LWS_NO_CLIENT
 835                         if (wsi->mode == LWSCM_WS_CLIENT) {
 836                                 n = lws_client_rx_sm(wsi, 0);
 837                                 if (n < 0)
 838                                         /* we closed wsi */
 839                                         n = 0;
 840                         } else
 841 #endif
 842                                 n = lws_rx_sm(wsi, 0);
 843
 844                         goto handled;
 845                 }
 846
 847                 if (wsi->u.ws.rx_draining_ext)
 848                         /*
 849                          * We have RX EXT content to drain, but can't do it
 850                          * right now.  That means we cannot do anything lower
 851                          * priority either.
 852                          */
 853                         break;
 854
 855                 /* 3: RX Flowcontrol buffer needs to be drained
 856                  */
 857
 858                 if (wsi->rxflow_buffer) {
 859                         lwsl_info("draining rxflow (len %d)\n",
 860                                 wsi->rxflow_len - wsi->rxflow_pos
 861                         );
 862                         /* well, drain it */
 863                         eff_buf.token = (char *)wsi->rxflow_buffer +
 864                                                 wsi->rxflow_pos;
 865                         eff_buf.token_len = wsi->rxflow_len - wsi->rxflow_pos;
 866                         draining_flow = 1;
 867                         goto drain;
 868                 }
 869
 870                 /* 4: any incoming (or ah-stashed incoming rx) data ready?
 871                  * notice if rx flow going off raced poll(), rx flow wins
 872                  */
 873
 874                 if (!(pollfd->revents & pollfd->events & LWS_POLLIN))
 875                         break;
 876
 877 read:
 878                 /* all the union members start with hdr, so even in ws mode
 879                  * we can deal with the ah via u.hdr
 880                  */
 881                 if (wsi->u.hdr.ah) {
 882                         lwsl_info("%s: %p: inherited ah rx\n", __func__, wsi);
 883                         eff_buf.token_len = wsi->u.hdr.ah->rxlen -
 884                                             wsi->u.hdr.ah->rxpos;
 885                         eff_buf.token = (char *)wsi->u.hdr.ah->rx +
 886                                         wsi->u.hdr.ah->rxpos;
 887                 } else {
 888                         if (wsi->mode != LWSCM_HTTP_CLIENT_ACCEPTED) {
 889                                 eff_buf.token_len = lws_ssl_capable_read(wsi,
 890                                         pt->serv_buf, pending ? pending :
 891                                                         LWS_MAX_SOCKET_IO_BUF);
 892                                 switch (eff_buf.token_len) {
 893                                 case 0:
 894                                         lwsl_info("%s: zero length read\n", __func__);
 895                                         goto close_and_handled;
 896                                 case LWS_SSL_CAPABLE_MORE_SERVICE:
 897                                         lwsl_info("SSL Capable more service\n");
 898                                         n = 0;
 899                                         goto handled;
 900                                 case LWS_SSL_CAPABLE_ERROR:
 901                                         lwsl_info("Closing when error\n");
 902                                         goto close_and_handled;
 903                                 }
 904
 905                                 eff_buf.token = (char *)pt->serv_buf;
 906                         }
 907                 }
 908
 909 drain:
 910 #ifndef LWS_NO_CLIENT
 911                 if (wsi->mode == LWSCM_HTTP_CLIENT_ACCEPTED) {
 912
 913                         /*
 914                          * simply mark ourselves as having readable data
 915                          * and turn off our POLLIN
 916                          */
 917                         wsi->client_rx_avail = 1;
 918                         lws_change_pollfd(wsi, LWS_POLLIN, 0);
 919
 920                         /* let user code know, he'll usually ask for writeable
 921                          * callback and drain / reenable it there
 922                          */
 923                         if (user_callback_handle_rxflow(
 924                                         wsi->protocol->callback,
 925                                         wsi, LWS_CALLBACK_RECEIVE_CLIENT_HTTP,
 926                                         wsi->user_space, NULL, 0))
 927                                 goto close_and_handled;
 928                 }
 929 #endif
 930                 /*
 931                  * give any active extensions a chance to munge the buffer
 932                  * before parse.  We pass in a pointer to an lws_tokens struct
 933                  * prepared with the default buffer and content length that's in
 934                  * there.  Rather than rewrite the default buffer, extensions
 935                  * that expect to grow the buffer can adapt .token to
 936                  * point to their own per-connection buffer in the extension
 937                  * user allocation.  By default with no extensions or no
 938                  * extension callback handling, just the normal input buffer is
 939                  * used then so it is efficient.
 940                  */
 941                 do {
 942                         more = 0;
 943
 944                         m = lws_ext_cb_active(wsi, LWS_EXT_CB_PACKET_RX_PREPARSE,
 945                                               &eff_buf, 0);
 946                         if (m < 0)
 947                                 goto close_and_handled;
 948                         if (m)
 949                                 more = 1;
 950
 951                         /* service incoming data */
 952
 953                         if (eff_buf.token_len) {
 954                                 /*
 955                                  * if draining from rxflow buffer, not
 956                                  * critical to track what was used since at the
 957                                  * use it bumps wsi->rxflow_pos.  If we come
 958                                  * around again it will pick up from where it
 959                                  * left off.
 960                                  */
 961                                 n = lws_read(wsi, (unsigned char *)eff_buf.token,
 962                                              eff_buf.token_len);
 963                                 if (n < 0) {
 964                                         /* we closed wsi */
 965                                         n = 0;
 966                                         goto handled;
 967                                 }
 968                         }
 969
 970                         eff_buf.token = NULL;
 971                         eff_buf.token_len = 0;
 972                 } while (more);
 973
 974                 if (wsi->u.hdr.ah) {
 975                         lwsl_info("%s: %p: detaching inherited used ah\n",
 976                                  __func__, wsi);
 977                         /* show we used all the pending rx up */
 978                         wsi->u.hdr.ah->rxpos = wsi->u.hdr.ah->rxlen;
 979                         /* we can run the normal ah detach flow despite
 980                          * being in ws union mode, since all union members
 981                          * start with hdr */
 982                         lws_header_table_detach(wsi, 0);
 983                 }
 984
 985                 pending = lws_ssl_pending(wsi);
 986                 if (pending) {
 987                         pending = pending > LWS_MAX_SOCKET_IO_BUF ?
 988                                         LWS_MAX_SOCKET_IO_BUF : pending;
 989                         goto read;
 990                 }
 991
 992                 if (draining_flow && wsi->rxflow_buffer &&
 993                     wsi->rxflow_pos == wsi->rxflow_len) {
 994                         lwsl_info("flow buffer: drained\n");
 995                         lws_free_set_NULL(wsi->rxflow_buffer);
 996                         /* having drained the rxflow buffer, can rearm POLLIN */
 997 #ifdef LWS_NO_SERVER
 998                         n =
 999 #endif
1000                         _lws_rx_flow_control(wsi);
1001                         /* n ignored, needed for NO_SERVER case */
1002                 }
1003
1004                 break;
1005 #ifdef LWS_WITH_CGI
1006         case LWSCM_CGI: /* we exist to handle a cgi's stdin/out/err data...
1007                          * do the callback on our master wsi
1008                          */
1009                 {
1010                         struct lws_cgi_args args;
1011
1012                         if (wsi->cgi_channel >= LWS_STDOUT &&
1013                             !(pollfd->revents & pollfd->events & LWS_POLLIN))
1014                                 break;
1015                         if (wsi->cgi_channel == LWS_STDIN &&
1016                             !(pollfd->revents & pollfd->events & LWS_POLLOUT))
1017                                 break;
1018
1019                         if (wsi->cgi_channel == LWS_STDIN)
1020                                 if (lws_change_pollfd(wsi, LWS_POLLOUT, 0)) {
1021                                         lwsl_info("failed at set pollfd\n");
1022                                         return 1;
1023                                 }
1024
1025                         args.ch = wsi->cgi_channel;
1026                         args.stdwsi = &wsi->parent->cgi->stdwsi[0];
1027                         args.hdr_state = wsi->hdr_state;
1028
1029                         //lwsl_err("CGI LWS_STDOUT waiting wsi %p mode %d state %d\n",
1030                         //       wsi->parent, wsi->parent->mode, wsi->parent->state);
1031
1032                         if (user_callback_handle_rxflow(
1033                                         wsi->parent->protocol->callback,
1034                                         wsi->parent, LWS_CALLBACK_CGI,
1035                                         wsi->parent->user_space,
1036                                         (void *)&args, 0))
1037                                 return 1;
1038
1039                         break;
1040                 }
1041 #endif
1042         default:
1043 #ifdef LWS_NO_CLIENT
1044                 break;
1045 #else
1046                 n = lws_client_socket_service(context, wsi, pollfd);
1047                 if (n)
1048                         return 1;
1049                 goto handled;
1050 #endif
1051         }
1052
1053         n = 0;
1054         goto handled;
1055
1056 close_and_handled:
1057         lwsl_debug("Close and handled\n");
1058         lws_close_free_wsi(wsi, LWS_CLOSE_STATUS_NOSTATUS);
1059         /*
1060          * pollfd may point to something else after the close
1061          * due to pollfd swapping scheme on delete on some platforms
1062          * we can't clear revents now because it'd be the wrong guy's revents
1063          */
1064         return 1;
1065
1066 handled:
1067         pollfd->revents = 0;
1068         return n;
1069 }
1070
1071 LWS_VISIBLE int
1072 lws_service_fd(struct lws_context *context, struct lws_pollfd *pollfd)
1073 {
1074         return lws_service_fd_tsi(context, pollfd, 0);
1075 }
1076
1077 /**
1078  * lws_service() - Service any pending websocket activity
1079  * @context:    Websocket context
1080  * @timeout_ms: Timeout for poll; 0 means return immediately if nothing needed
1081  *              service otherwise block and service immediately, returning
1082  *              after the timeout if nothing needed service.
1083  *
1084  *      This function deals with any pending websocket traffic, for three
1085  *      kinds of event.  It handles these events on both server and client
1086  *      types of connection the same.
1087  *
1088  *      1) Accept new connections to our context's server
1089  *
1090  *      2) Call the receive callback for incoming frame data received by
1091  *          server or client connections.
1092  *
1093  *      You need to call this service function periodically to all the above
1094  *      functions to happen; if your application is single-threaded you can
1095  *      just call it in your main event loop.
1096  *
1097  *      Alternatively you can fork a new process that asynchronously handles
1098  *      calling this service in a loop.  In that case you are happy if this
1099  *      call blocks your thread until it needs to take care of something and
1100  *      would call it with a large nonzero timeout.  Your loop then takes no
1101  *      CPU while there is nothing happening.
1102  *
1103  *      If you are calling it in a single-threaded app, you don't want it to
1104  *      wait around blocking other things in your loop from happening, so you
1105  *      would call it with a timeout_ms of 0, so it returns immediately if
1106  *      nothing is pending, or as soon as it services whatever was pending.
1107  */
1108
1109 LWS_VISIBLE int
1110 lws_service(struct lws_context *context, int timeout_ms)
1111 {
1112         return lws_plat_service(context, timeout_ms);
1113 }
1114
1115 LWS_VISIBLE int
1116 lws_service_tsi(struct lws_context *context, int timeout_ms, int tsi)
1117 {
1118         return lws_plat_service_tsi(context, timeout_ms, tsi);
1119 }
1120