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         int n = 0;
 314
 315         /*
 316          * if extensions want in on it (eg, we are a mux parent)
 317          * give them a chance to service child timeouts
 318          */
 319         if (lws_ext_cb_active(wsi, LWS_EXT_CB_1HZ, NULL, sec) < 0)
 320                 return 0;
 321
 322         if (!wsi->pending_timeout)
 323                 return 0;
 324
 325         /*
 326          * if we went beyond the allowed time, kill the
 327          * connection
 328          */
 329         if ((time_t)sec > wsi->pending_timeout_limit) {
 330 #if LWS_POSIX
 331                 if (wsi->sock != LWS_SOCK_INVALID)
 332                         n = pt->fds[wsi->sock].events;
 333
 334                 /* no need to log normal idle keepalive timeout */
 335                 if (wsi->pending_timeout != PENDING_TIMEOUT_HTTP_KEEPALIVE_IDLE)
 336                         lwsl_notice("wsi %p: TIMEDOUT WAITING on %d (did hdr %d, ah %p, wl %d, pfd events %d)\n",
 337                             (void *)wsi, wsi->pending_timeout,
 338                             wsi->hdr_parsing_completed, wsi->u.hdr.ah,
 339                             pt->ah_wait_list_length, n);
 340 #endif
 341                 /*
 342                  * Since he failed a timeout, he already had a chance to do
 343                  * something and was unable to... that includes situations like
 344                  * half closed connections.  So process this "failed timeout"
 345                  * close as a violent death and don't try to do protocol
 346                  * cleanup like flush partials.
 347                  */
 348                 wsi->socket_is_permanently_unusable = 1;
 349                 if (wsi->mode == LWSCM_WSCL_WAITING_SSL)
 350                         wsi->vhost->protocols[0].callback(wsi,
 351                                 LWS_CALLBACK_CLIENT_CONNECTION_ERROR,
 352                                 wsi->user_space, NULL, 0);
 353
 354                 lws_close_free_wsi(wsi, LWS_CLOSE_STATUS_NOSTATUS);
 355
 356                 return 1;
 357         }
 358
 359         return 0;
 360 }
 361
 362 int lws_rxflow_cache(struct lws *wsi, unsigned char *buf, int n, int len)
 363 {
 364         /* his RX is flowcontrolled, don't send remaining now */
 365         if (wsi->rxflow_buffer) {
 366                 /* rxflow while we were spilling prev rxflow */
 367                 lwsl_info("stalling in existing rxflow buf\n");
 368                 return 1;
 369         }
 370
 371         /* a new rxflow, buffer it and warn caller */
 372         lwsl_info("new rxflow input buffer len %d\n", len - n);
 373         wsi->rxflow_buffer = lws_malloc(len - n);
 374         if (!wsi->rxflow_buffer)
 375                 return -1;
 376         wsi->rxflow_len = len - n;
 377         wsi->rxflow_pos = 0;
 378         memcpy(wsi->rxflow_buffer, buf + n, len - n);
 379
 380         return 0;
 381 }
 382
 383 /* this is used by the platform service code to stop us waiting for network
 384  * activity in poll() when we have something that already needs service
 385  */
 386
 387 int
 388 lws_service_adjust_timeout(struct lws_context *context, int timeout_ms, int tsi)
 389 {
 390         struct lws_context_per_thread *pt = &context->pt[tsi];
 391         int n;
 392
 393         /* Figure out if we really want to wait in poll()
 394          * We only need to wait if really nothing already to do and we have
 395          * to wait for something from network
 396          */
 397
 398         /* 1) if we know we are draining rx ext, do not wait in poll */
 399         if (pt->rx_draining_ext_list)
 400                 return 0;
 401
 402 #ifdef LWS_OPENSSL_SUPPORT
 403         /* 2) if we know we have non-network pending data, do not wait in poll */
 404         if (lws_ssl_anybody_has_buffered_read_tsi(context, tsi)) {
 405                 lwsl_info("ssl buffered read\n");
 406                 return 0;
 407         }
 408 #endif
 409
 410         /* 3) if any ah has pending rx, do not wait in poll */
 411         for (n = 0; n < context->max_http_header_pool; n++)
 412                 if (pt->ah_pool[n].rxpos != pt->ah_pool[n].rxlen) {
 413                         /* any ah with pending rx must be attached to someone */
 414                         if (!pt->ah_pool[n].wsi) {
 415                                 lwsl_err("%s: assert: no wsi attached to ah\n", __func__);
 416                                 assert(0);
 417                         }
 418                         return 0;
 419                 }
 420
 421         return timeout_ms;
 422 }
 423
 424 /*
 425  * guys that need POLLIN service again without waiting for network action
 426  * can force POLLIN here if not flowcontrolled, so they will get service.
 427  *
 428  * Return nonzero if anybody got their POLLIN faked
 429  */
 430 int
 431 lws_service_flag_pending(struct lws_context *context, int tsi)
 432 {
 433         struct lws_context_per_thread *pt = &context->pt[tsi];
 434 #ifdef LWS_OPENSSL_SUPPORT
 435         struct lws *wsi_next;
 436 #endif
 437         struct lws *wsi;
 438         int forced = 0;
 439         int n;
 440
 441         /* POLLIN faking */
 442
 443         /*
 444          * 1) For all guys with already-available ext data to drain, if they are
 445          * not flowcontrolled, fake their POLLIN status
 446          */
 447         wsi = pt->rx_draining_ext_list;
 448         while (wsi) {
 449                 pt->fds[wsi->position_in_fds_table].revents |=
 450                         pt->fds[wsi->position_in_fds_table].events & LWS_POLLIN;
 451                 if (pt->fds[wsi->position_in_fds_table].revents &
 452                     LWS_POLLIN)
 453                         forced = 1;
 454                 wsi = wsi->u.ws.rx_draining_ext_list;
 455         }
 456
 457 #ifdef LWS_OPENSSL_SUPPORT
 458         /*
 459          * 2) For all guys with buffered SSL read data already saved up, if they
 460          * are not flowcontrolled, fake their POLLIN status so they'll get
 461          * service to use up the buffered incoming data, even though their
 462          * network socket may have nothing
 463          */
 464         wsi = pt->pending_read_list;
 465         while (wsi) {
 466                 wsi_next = wsi->pending_read_list_next;
 467                 pt->fds[wsi->position_in_fds_table].revents |=
 468                         pt->fds[wsi->position_in_fds_table].events & LWS_POLLIN;
 469                 if (pt->fds[wsi->position_in_fds_table].revents & LWS_POLLIN) {
 470                         forced = 1;
 471                         /*
 472                          * he's going to get serviced now, take him off the
 473                          * list of guys with buffered SSL.  If he still has some
 474                          * at the end of the service, he'll get put back on the
 475                          * list then.
 476                          */
 477                         lws_ssl_remove_wsi_from_buffered_list(wsi);
 478                 }
 479
 480                 wsi = wsi_next;
 481         }
 482 #endif
 483         /*
 484          * 3) For any wsi who have an ah with pending RX who did not
 485          * complete their current headers, and are not flowcontrolled,
 486          * fake their POLLIN status so they will be able to drain the
 487          * rx buffered in the ah
 488          */
 489         for (n = 0; n < context->max_http_header_pool; n++)
 490                 if (pt->ah_pool[n].rxpos != pt->ah_pool[n].rxlen &&
 491                     !pt->ah_pool[n].wsi->hdr_parsing_completed) {
 492                         pt->fds[pt->ah_pool[n].wsi->position_in_fds_table].revents |=
 493                                 pt->fds[pt->ah_pool[n].wsi->position_in_fds_table].events &
 494                                         LWS_POLLIN;
 495                         if (pt->fds[pt->ah_pool[n].wsi->position_in_fds_table].revents &
 496                             LWS_POLLIN)
 497                                 forced = 1;
 498                 }
 499
 500         return forced;
 501 }
 502
 503 #ifndef LWS_NO_CLIENT
 504
 505 LWS_VISIBLE int
 506 lws_http_client_read(struct lws *wsi, char **buf, int *len)
 507 {
 508         int rlen, n;
 509
 510
 511
 512         rlen = lws_ssl_capable_read(wsi, (unsigned char *)*buf, *len);
 513         if (rlen < 0)
 514                 return -1;
 515
 516         *len = rlen;
 517         if (rlen == 0)
 518                 return 0;
 519
 520 //      lwsl_err("%s: read %d\n", __func__, rlen);
 521
 522         /* allow the source to signal he has data again next time */
 523         wsi->client_rx_avail = 0;
 524         lws_change_pollfd(wsi, 0, LWS_POLLIN);
 525
 526         /*
 527          * server may insist on transfer-encoding: chunked,
 528          * so http client must deal with it
 529          */
 530 spin_chunks:
 531         while (wsi->chunked && (wsi->chunk_parser != ELCP_CONTENT) && *len) {
 532                 switch (wsi->chunk_parser) {
 533                 case ELCP_HEX:
 534                         if ((*buf)[0] == '\x0d') {
 535                                 wsi->chunk_parser = ELCP_CR;
 536                                 break;
 537                         }
 538                         n = char_to_hex((*buf)[0]);
 539                         if (n < 0)
 540                                 return -1;
 541                         wsi->chunk_remaining <<= 4;
 542                         wsi->chunk_remaining |= n;
 543                         break;
 544                 case ELCP_CR:
 545                         if ((*buf)[0] != '\x0a')
 546                                 return -1;
 547                         wsi->chunk_parser = ELCP_CONTENT;
 548                         lwsl_info("chunk %d\n", wsi->chunk_remaining);
 549                         if (wsi->chunk_remaining)
 550                                 break;
 551                         lwsl_info("final chunk\n");
 552                         goto completed;
 553
 554                 case ELCP_CONTENT:
 555                         break;
 556
 557                 case ELCP_POST_CR:
 558                         if ((*buf)[0] != '\x0d')
 559                                 return -1;
 560
 561                         wsi->chunk_parser = ELCP_POST_LF;
 562                         break;
 563
 564                 case ELCP_POST_LF:
 565                         if ((*buf)[0] != '\x0a')
 566                                 return -1;
 567
 568                         wsi->chunk_parser = ELCP_HEX;
 569                         wsi->chunk_remaining = 0;
 570                         break;
 571                 }
 572                 (*buf)++;
 573                 (*len)--;
 574         }
 575
 576         if (wsi->chunked && !wsi->chunk_remaining)
 577                 return 0;
 578
 579         if (wsi->u.http.content_remain &&
 580             (int)wsi->u.http.content_remain < *len)
 581                 n = wsi->u.http.content_remain;
 582         else
 583                 n = *len;
 584
 585         if (wsi->chunked && wsi->chunk_remaining &&
 586             wsi->chunk_remaining < n)
 587                 n = wsi->chunk_remaining;
 588
 589 #ifdef LWS_WITH_HTTP_PROXY
 590         /* hubbub */
 591         if (wsi->perform_rewrite)
 592                 lws_rewrite_parse(wsi->rw, (unsigned char *)*buf, n);
 593         else
 594 #endif
 595                 if (user_callback_handle_rxflow(wsi->protocol->callback,
 596                                 wsi, LWS_CALLBACK_RECEIVE_CLIENT_HTTP_READ,
 597                                 wsi->user_space, *buf, n))
 598                         return -1;
 599
 600         if (wsi->chunked && wsi->chunk_remaining) {
 601                 (*buf) += n;
 602                 wsi->chunk_remaining -= n;
 603                 *len -= n;
 604         }
 605
 606         if (wsi->chunked && !wsi->chunk_remaining)
 607                 wsi->chunk_parser = ELCP_POST_CR;
 608
 609         if (wsi->chunked && *len) {
 610                 goto spin_chunks;
 611         }
 612
 613         if (wsi->chunked)
 614                 return 0;
 615
 616         wsi->u.http.content_remain -= n;
 617         if (wsi->u.http.content_remain || !wsi->u.http.content_length)
 618                 return 0;
 619
 620 completed:
 621         if (user_callback_handle_rxflow(wsi->protocol->callback,
 622                         wsi, LWS_CALLBACK_COMPLETED_CLIENT_HTTP,
 623                         wsi->user_space, NULL, 0))
 624                 return -1;
 625
 626         if (lws_http_transaction_completed_client(wsi))
 627                 return -1;
 628
 629         return 0;
 630 }
 631 #endif
 632
 633 /**
 634  * lws_service_fd() - Service polled socket with something waiting
 635  * @context:    Websocket context
 636  * @pollfd:     The pollfd entry describing the socket fd and which events
 637  *              happened.
 638  *
 639  *      This function takes a pollfd that has POLLIN or POLLOUT activity and
 640  *      services it according to the state of the associated
 641  *      struct lws.
 642  *
 643  *      The one call deals with all "service" that might happen on a socket
 644  *      including listen accepts, http files as well as websocket protocol.
 645  *
 646  *      If a pollfd says it has something, you can just pass it to
 647  *      lws_service_fd() whether it is a socket handled by lws or not.
 648  *      If it sees it is a lws socket, the traffic will be handled and
 649  *      pollfd->revents will be zeroed now.
 650  *
 651  *      If the socket is foreign to lws, it leaves revents alone.  So you can
 652  *      see if you should service yourself by checking the pollfd revents
 653  *      after letting lws try to service it.
 654  */
 655
 656 LWS_VISIBLE int
 657 lws_service_fd_tsi(struct lws_context *context, struct lws_pollfd *pollfd, int tsi)
 658 {
 659         struct lws_context_per_thread *pt = &context->pt[tsi];
 660         lws_sockfd_type our_fd = 0, tmp_fd;
 661         struct lws_tokens eff_buf;
 662         unsigned int pending = 0;
 663         struct lws *wsi, *wsi1;
 664         char draining_flow = 0;
 665         int timed_out = 0;
 666         time_t now;
 667         int n = 0, m;
 668         int more;
 669
 670         if (!context->protocol_init_done)
 671                 lws_protocol_init(context);
 672
 673         /*
 674          * you can call us with pollfd = NULL to just allow the once-per-second
 675          * global timeout checks; if less than a second since the last check
 676          * it returns immediately then.
 677          */
 678
 679         time(&now);
 680
 681         /*
 682          * handle case that system time was uninitialized when lws started
 683          * at boot, and got initialized a little later
 684          */
 685         if (context->time_up < 1464083026 && now > 1464083026)
 686                 context->time_up = now;
 687
 688         /* TODO: if using libev, we should probably use timeout watchers... */
 689         if (context->last_timeout_check_s != now) {
 690                 context->last_timeout_check_s = now;
 691
 692                 lws_plat_service_periodic(context);
 693
 694                 /* global timeout check once per second */
 695
 696                 if (pollfd)
 697                         our_fd = pollfd->fd;
 698
 699                 wsi = context->pt[tsi].timeout_list;
 700                 while (wsi) {
 701                         /* we have to take copies, because he may be deleted */
 702                         wsi1 = wsi->timeout_list;
 703                         tmp_fd = wsi->sock;
 704                         if (lws_service_timeout_check(wsi, (unsigned int)now)) {
 705                                 /* he did time out... */
 706                                 if (tmp_fd == our_fd)
 707                                         /* it was the guy we came to service! */
 708                                         timed_out = 1;
 709                                         /* he's gone, no need to mark as handled */
 710                         }
 711                         wsi = wsi1;
 712                 }
 713 #ifdef LWS_WITH_CGI
 714                 lws_cgi_kill_terminated(pt);
 715 #endif
 716 #if 0
 717                 {
 718                         char s[300], *p = s;
 719
 720                         for (n = 0; n < context->count_threads; n++)
 721                                 p += sprintf(p, " %7lu (%5d), ",
 722                                              context->pt[n].count_conns,
 723                                              context->pt[n].fds_count);
 724
 725                         lwsl_notice("load: %s\n", s);
 726                 }
 727 #endif
 728         }
 729
 730         /* the socket we came to service timed out, nothing to do */
 731         if (timed_out)
 732                 return 0;
 733
 734         /* just here for timeout management? */
 735         if (!pollfd)
 736                 return 0;
 737
 738         /* no, here to service a socket descriptor */
 739         wsi = wsi_from_fd(context, pollfd->fd);
 740         if (!wsi)
 741                 /* not lws connection ... leave revents alone and return */
 742                 return 0;
 743
 744         /*
 745          * so that caller can tell we handled, past here we need to
 746          * zero down pollfd->revents after handling
 747          */
 748
 749 #if LWS_POSIX
 750         /* handle session socket closed */
 751
 752         if ((!(pollfd->revents & pollfd->events & LWS_POLLIN)) &&
 753             (pollfd->revents & LWS_POLLHUP)) {
 754                 wsi->socket_is_permanently_unusable = 1;
 755                 lwsl_debug("Session Socket %p (fd=%d) dead\n",
 756                                                        (void *)wsi, pollfd->fd);
 757
 758                 goto close_and_handled;
 759         }
 760
 761 #ifdef _WIN32
 762         if (pollfd->revents & LWS_POLLOUT)
 763                 wsi->sock_send_blocking = FALSE;
 764 #endif
 765
 766 #endif
 767
 768         lwsl_debug("fd=%d, revents=%d\n", pollfd->fd, pollfd->revents);
 769
 770         /* okay, what we came here to do... */
 771
 772         switch (wsi->mode) {
 773         case LWSCM_HTTP_SERVING:
 774         case LWSCM_HTTP_CLIENT:
 775         case LWSCM_HTTP_SERVING_ACCEPTED:
 776         case LWSCM_SERVER_LISTENER:
 777         case LWSCM_SSL_ACK_PENDING:
 778                 if (wsi->state == LWSS_CLIENT_HTTP_ESTABLISHED)
 779                         goto handled;
 780
 781 #ifdef LWS_WITH_CGI
 782                 if (wsi->cgi && (pollfd->revents & LWS_POLLOUT)) {
 783                         n = lws_handle_POLLOUT_event(wsi, pollfd);
 784                         if (n)
 785                                 goto close_and_handled;
 786                         goto handled;
 787                 }
 788 #endif
 789                 n = lws_server_socket_service(context, wsi, pollfd);
 790                 if (n) /* closed by above */
 791                         return 1;
 792                 goto handled;
 793
 794         case LWSCM_WS_SERVING:
 795         case LWSCM_WS_CLIENT:
 796         case LWSCM_HTTP2_SERVING:
 797         case LWSCM_HTTP_CLIENT_ACCEPTED:
 798
 799                 /* 1: something requested a callback when it was OK to write */
 800
 801                 if ((pollfd->revents & LWS_POLLOUT) &&
 802                     (wsi->state == LWSS_ESTABLISHED ||
 803                      wsi->state == LWSS_HTTP2_ESTABLISHED ||
 804                      wsi->state == LWSS_HTTP2_ESTABLISHED_PRE_SETTINGS ||
 805                      wsi->state == LWSS_RETURNED_CLOSE_ALREADY ||
 806                      wsi->state == LWSS_FLUSHING_STORED_SEND_BEFORE_CLOSE) &&
 807                     lws_handle_POLLOUT_event(wsi, pollfd)) {
 808                         if (wsi->state == LWSS_RETURNED_CLOSE_ALREADY)
 809                                 wsi->state = LWSS_FLUSHING_STORED_SEND_BEFORE_CLOSE;
 810                         lwsl_info("lws_service_fd: closing\n");
 811                         goto close_and_handled;
 812                 }
 813
 814                 if (wsi->state == LWSS_RETURNED_CLOSE_ALREADY ||
 815                     wsi->state == LWSS_AWAITING_CLOSE_ACK) {
 816                         /*
 817                          * we stopped caring about anything except control
 818                          * packets.  Force flow control off, defeat tx
 819                          * draining.
 820                          */
 821                         lws_rx_flow_control(wsi, 1);
 822                         wsi->u.ws.tx_draining_ext = 0;
 823                 }
 824
 825                 if (wsi->u.ws.tx_draining_ext)
 826                         /* we cannot deal with new RX until the TX ext
 827                          * path has been drained.  It's because new
 828                          * rx will, eg, crap on the wsi rx buf that
 829                          * may be needed to retain state.
 830                          *
 831                          * TX ext drain path MUST go through event loop
 832                          * to avoid blocking.
 833                          */
 834                         break;
 835
 836                 if (!(wsi->rxflow_change_to & LWS_RXFLOW_ALLOW))
 837                         /* We cannot deal with any kind of new RX
 838                          * because we are RX-flowcontrolled.
 839                          */
 840                         break;
 841
 842                 /* 2: RX Extension needs to be drained
 843                  */
 844
 845                 if (wsi->state == LWSS_ESTABLISHED &&
 846                     wsi->u.ws.rx_draining_ext) {
 847
 848                         lwsl_ext("%s: RX EXT DRAINING: Service\n", __func__);
 849 #ifndef LWS_NO_CLIENT
 850                         if (wsi->mode == LWSCM_WS_CLIENT) {
 851                                 n = lws_client_rx_sm(wsi, 0);
 852                                 if (n < 0)
 853                                         /* we closed wsi */
 854                                         n = 0;
 855                         } else
 856 #endif
 857                                 n = lws_rx_sm(wsi, 0);
 858
 859                         goto handled;
 860                 }
 861
 862                 if (wsi->u.ws.rx_draining_ext)
 863                         /*
 864                          * We have RX EXT content to drain, but can't do it
 865                          * right now.  That means we cannot do anything lower
 866                          * priority either.
 867                          */
 868                         break;
 869
 870                 /* 3: RX Flowcontrol buffer needs to be drained
 871                  */
 872
 873                 if (wsi->rxflow_buffer) {
 874                         lwsl_info("draining rxflow (len %d)\n",
 875                                 wsi->rxflow_len - wsi->rxflow_pos
 876                         );
 877                         /* well, drain it */
 878                         eff_buf.token = (char *)wsi->rxflow_buffer +
 879                                                 wsi->rxflow_pos;
 880                         eff_buf.token_len = wsi->rxflow_len - wsi->rxflow_pos;
 881                         draining_flow = 1;
 882                         goto drain;
 883                 }
 884
 885                 /* 4: any incoming (or ah-stashed incoming rx) data ready?
 886                  * notice if rx flow going off raced poll(), rx flow wins
 887                  */
 888
 889                 if (!(pollfd->revents & pollfd->events & LWS_POLLIN))
 890                         break;
 891
 892 read:
 893                 /* all the union members start with hdr, so even in ws mode
 894                  * we can deal with the ah via u.hdr
 895                  */
 896                 if (wsi->u.hdr.ah) {
 897                         lwsl_info("%s: %p: inherited ah rx\n", __func__, wsi);
 898                         eff_buf.token_len = wsi->u.hdr.ah->rxlen -
 899                                             wsi->u.hdr.ah->rxpos;
 900                         eff_buf.token = (char *)wsi->u.hdr.ah->rx +
 901                                         wsi->u.hdr.ah->rxpos;
 902                 } else {
 903                         if (wsi->mode != LWSCM_HTTP_CLIENT_ACCEPTED) {
 904                                 eff_buf.token_len = lws_ssl_capable_read(wsi,
 905                                         pt->serv_buf, pending ? pending :
 906                                         context->pt_serv_buf_size);
 907                                 switch (eff_buf.token_len) {
 908                                 case 0:
 909                                         lwsl_info("%s: zero length read\n", __func__);
 910                                         goto close_and_handled;
 911                                 case LWS_SSL_CAPABLE_MORE_SERVICE:
 912                                         lwsl_info("SSL Capable more service\n");
 913                                         n = 0;
 914                                         goto handled;
 915                                 case LWS_SSL_CAPABLE_ERROR:
 916                                         lwsl_info("Closing when error\n");
 917                                         goto close_and_handled;
 918                                 }
 919
 920                                 eff_buf.token = (char *)pt->serv_buf;
 921                         }
 922                 }
 923
 924 drain:
 925 #ifndef LWS_NO_CLIENT
 926                 if (wsi->mode == LWSCM_HTTP_CLIENT_ACCEPTED) {
 927
 928                         /*
 929                          * simply mark ourselves as having readable data
 930                          * and turn off our POLLIN
 931                          */
 932                         wsi->client_rx_avail = 1;
 933                         lws_change_pollfd(wsi, LWS_POLLIN, 0);
 934
 935                         /* let user code know, he'll usually ask for writeable
 936                          * callback and drain / reenable it there
 937                          */
 938                         if (user_callback_handle_rxflow(
 939                                         wsi->protocol->callback,
 940                                         wsi, LWS_CALLBACK_RECEIVE_CLIENT_HTTP,
 941                                         wsi->user_space, NULL, 0))
 942                                 goto close_and_handled;
 943                 }
 944 #endif
 945                 /*
 946                  * give any active extensions a chance to munge the buffer
 947                  * before parse.  We pass in a pointer to an lws_tokens struct
 948                  * prepared with the default buffer and content length that's in
 949                  * there.  Rather than rewrite the default buffer, extensions
 950                  * that expect to grow the buffer can adapt .token to
 951                  * point to their own per-connection buffer in the extension
 952                  * user allocation.  By default with no extensions or no
 953                  * extension callback handling, just the normal input buffer is
 954                  * used then so it is efficient.
 955                  */
 956                 do {
 957                         more = 0;
 958
 959                         m = lws_ext_cb_active(wsi, LWS_EXT_CB_PACKET_RX_PREPARSE,
 960                                               &eff_buf, 0);
 961                         if (m < 0)
 962                                 goto close_and_handled;
 963                         if (m)
 964                                 more = 1;
 965
 966                         /* service incoming data */
 967
 968                         if (eff_buf.token_len) {
 969                                 /*
 970                                  * if draining from rxflow buffer, not
 971                                  * critical to track what was used since at the
 972                                  * use it bumps wsi->rxflow_pos.  If we come
 973                                  * around again it will pick up from where it
 974                                  * left off.
 975                                  */
 976                                 n = lws_read(wsi, (unsigned char *)eff_buf.token,
 977                                              eff_buf.token_len);
 978                                 if (n < 0) {
 979                                         /* we closed wsi */
 980                                         n = 0;
 981                                         goto handled;
 982                                 }
 983                         }
 984
 985                         eff_buf.token = NULL;
 986                         eff_buf.token_len = 0;
 987                 } while (more);
 988
 989                 if (wsi->u.hdr.ah) {
 990                         lwsl_info("%s: %p: detaching inherited used ah\n",
 991                                  __func__, wsi);
 992                         /* show we used all the pending rx up */
 993                         wsi->u.hdr.ah->rxpos = wsi->u.hdr.ah->rxlen;
 994                         /* we can run the normal ah detach flow despite
 995                          * being in ws union mode, since all union members
 996                          * start with hdr */
 997                         lws_header_table_detach(wsi, 0);
 998                 }
 999
1000                 pending = lws_ssl_pending(wsi);
1001                 if (pending) {
1002                         pending = pending > context->pt_serv_buf_size ?
1003                                         context->pt_serv_buf_size : pending;
1004                         goto read;
1005                 }
1006
1007                 if (draining_flow && wsi->rxflow_buffer &&
1008                     wsi->rxflow_pos == wsi->rxflow_len) {
1009                         lwsl_info("flow buffer: drained\n");
1010                         lws_free_set_NULL(wsi->rxflow_buffer);
1011                         /* having drained the rxflow buffer, can rearm POLLIN */
1012 #ifdef LWS_NO_SERVER
1013                         n =
1014 #endif
1015                         _lws_rx_flow_control(wsi);
1016                         /* n ignored, needed for NO_SERVER case */
1017                 }
1018
1019                 break;
1020 #ifdef LWS_WITH_CGI
1021         case LWSCM_CGI: /* we exist to handle a cgi's stdin/out/err data...
1022                          * do the callback on our master wsi
1023                          */
1024                 {
1025                         struct lws_cgi_args args;
1026
1027                         if (wsi->cgi_channel >= LWS_STDOUT &&
1028                             !(pollfd->revents & pollfd->events & LWS_POLLIN))
1029                                 break;
1030                         if (wsi->cgi_channel == LWS_STDIN &&
1031                             !(pollfd->revents & pollfd->events & LWS_POLLOUT))
1032                                 break;
1033
1034                         if (wsi->cgi_channel == LWS_STDIN)
1035                                 if (lws_change_pollfd(wsi, LWS_POLLOUT, 0)) {
1036                                         lwsl_info("failed at set pollfd\n");
1037                                         return 1;
1038                                 }
1039
1040                         args.ch = wsi->cgi_channel;
1041                         args.stdwsi = &wsi->parent->cgi->stdwsi[0];
1042                         args.hdr_state = wsi->hdr_state;
1043
1044                         //lwsl_err("CGI LWS_STDOUT waiting wsi %p mode %d state %d\n",
1045                         //       wsi->parent, wsi->parent->mode, wsi->parent->state);
1046
1047                         if (user_callback_handle_rxflow(
1048                                         wsi->parent->protocol->callback,
1049                                         wsi->parent, LWS_CALLBACK_CGI,
1050                                         wsi->parent->user_space,
1051                                         (void *)&args, 0))
1052                                 return 1;
1053
1054                         break;
1055                 }
1056 #endif
1057         default:
1058 #ifdef LWS_NO_CLIENT
1059                 break;
1060 #else
1061                 n = lws_client_socket_service(context, wsi, pollfd);
1062                 if (n)
1063                         return 1;
1064                 goto handled;
1065 #endif
1066         }
1067
1068         n = 0;
1069         goto handled;
1070
1071 close_and_handled:
1072         lwsl_debug("Close and handled\n");
1073         lws_close_free_wsi(wsi, LWS_CLOSE_STATUS_NOSTATUS);
1074         /*
1075          * pollfd may point to something else after the close
1076          * due to pollfd swapping scheme on delete on some platforms
1077          * we can't clear revents now because it'd be the wrong guy's revents
1078          */
1079         return 1;
1080
1081 handled:
1082         pollfd->revents = 0;
1083         return n;
1084 }
1085
1086 LWS_VISIBLE int
1087 lws_service_fd(struct lws_context *context, struct lws_pollfd *pollfd)
1088 {
1089         return lws_service_fd_tsi(context, pollfd, 0);
1090 }
1091
1092 /**
1093  * lws_service() - Service any pending websocket activity
1094  * @context:    Websocket context
1095  * @timeout_ms: Timeout for poll; 0 means return immediately if nothing needed
1096  *              service otherwise block and service immediately, returning
1097  *              after the timeout if nothing needed service.
1098  *
1099  *      This function deals with any pending websocket traffic, for three
1100  *      kinds of event.  It handles these events on both server and client
1101  *      types of connection the same.
1102  *
1103  *      1) Accept new connections to our context's server
1104  *
1105  *      2) Call the receive callback for incoming frame data received by
1106  *          server or client connections.
1107  *
1108  *      You need to call this service function periodically to all the above
1109  *      functions to happen; if your application is single-threaded you can
1110  *      just call it in your main event loop.
1111  *
1112  *      Alternatively you can fork a new process that asynchronously handles
1113  *      calling this service in a loop.  In that case you are happy if this
1114  *      call blocks your thread until it needs to take care of something and
1115  *      would call it with a large nonzero timeout.  Your loop then takes no
1116  *      CPU while there is nothing happening.
1117  *
1118  *      If you are calling it in a single-threaded app, you don't want it to
1119  *      wait around blocking other things in your loop from happening, so you
1120  *      would call it with a timeout_ms of 0, so it returns immediately if
1121  *      nothing is pending, or as soon as it services whatever was pending.
1122  */
1123
1124 LWS_VISIBLE int
1125 lws_service(struct lws_context *context, int timeout_ms)
1126 {
1127         return lws_plat_service(context, timeout_ms);
1128 }
1129
1130 LWS_VISIBLE int
1131 lws_service_tsi(struct lws_context *context, int timeout_ms, int tsi)
1132 {
1133         return lws_plat_service_tsi(context, timeout_ms, tsi);
1134 }
1135