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         struct lws_context_per_thread *pt = &wsi->context->pt[(int)wsi->tsi];
  28         int n;
  29
  30         lws_stats_atomic_bump(wsi->context, pt, LWSSTATS_C_WRITEABLE_CB, 1);
  31 #if defined(LWS_WITH_STATS)
  32         {
  33                 uint64_t ul = time_in_microseconds() - wsi->active_writable_req_us;
  34
  35                 lws_stats_atomic_bump(wsi->context, pt, LWSSTATS_MS_WRITABLE_DELAY, ul);
  36                 lws_stats_atomic_max(wsi->context, pt, LWSSTATS_MS_WORST_WRITABLE_DELAY, ul);
  37                 wsi->active_writable_req_us = 0;
  38         }
  39 #endif
  40
  41         switch (wsi->mode) {
  42         case LWSCM_RAW:
  43                 n = LWS_CALLBACK_RAW_WRITEABLE;
  44                 break;
  45         case LWSCM_RAW_FILEDESC:
  46                 n = LWS_CALLBACK_RAW_WRITEABLE_FILE;
  47                 break;
  48         case LWSCM_WS_CLIENT:
  49                 n = LWS_CALLBACK_CLIENT_WRITEABLE;
  50                 break;
  51         case LWSCM_WSCL_ISSUE_HTTP_BODY:
  52                 n = LWS_CALLBACK_CLIENT_HTTP_WRITEABLE;
  53                 break;
  54         case LWSCM_WS_SERVING:
  55                 n = LWS_CALLBACK_SERVER_WRITEABLE;
  56                 break;
  57         default:
  58                 n = LWS_CALLBACK_HTTP_WRITEABLE;
  59                 break;
  60         }
  61         lwsl_debug("%s: %p (user=%p)\n", __func__, wsi, wsi->user_space);
  62         return user_callback_handle_rxflow(wsi->protocol->callback,
  63                                            wsi, (enum lws_callback_reasons) n,
  64                                            wsi->user_space, NULL, 0);
  65 }
  66
  67 int
  68 lws_handle_POLLOUT_event(struct lws *wsi, struct lws_pollfd *pollfd)
  69 {
  70         int write_type = LWS_WRITE_PONG;
  71         struct lws_tokens eff_buf;
  72 #ifdef LWS_USE_HTTP2
  73         struct lws *wsi2;
  74 #endif
  75         int ret, m, n;
  76
  77         //lwsl_err("%s: %p\n", __func__, wsi);
  78
  79         wsi->leave_pollout_active = 0;
  80         wsi->handling_pollout = 1;
  81         /*
  82          * if another thread wants POLLOUT on us, from here on while
  83          * handling_pollout is set, he will only set leave_pollout_active.
  84          * If we are going to disable POLLOUT, we will check that first.
  85          */
  86
  87         /*
  88          * user callback is lowest priority to get these notifications
  89          * actually, since other pending things cannot be disordered
  90          */
  91
  92         /* Priority 1: pending truncated sends are incomplete ws fragments
  93          *             If anything else sent first the protocol would be
  94          *             corrupted.
  95          */
  96         if (wsi->trunc_len) {
  97                 if (lws_issue_raw(wsi, wsi->trunc_alloc + wsi->trunc_offset,
  98                                   wsi->trunc_len) < 0) {
  99                         lwsl_info("%s signalling to close\n", __func__);
 100                         goto bail_die;
 101                 }
 102                 /* leave POLLOUT active either way */
 103                 goto bail_ok;
 104         } else
 105                 if (wsi->state == LWSS_FLUSHING_STORED_SEND_BEFORE_CLOSE) {
 106                         wsi->socket_is_permanently_unusable = 1;
 107                         goto bail_die; /* retry closing now */
 108                 }
 109
 110         if (wsi->mode == LWSCM_WSCL_ISSUE_HTTP_BODY)
 111                 goto user_service;
 112
 113
 114 #ifdef LWS_USE_HTTP2
 115         /* Priority 2: protocol packets
 116          */
 117         if (wsi->pps) {
 118                 lwsl_info("servicing pps %d\n", wsi->pps);
 119                 switch (wsi->pps) {
 120                 case LWS_PPS_HTTP2_MY_SETTINGS:
 121                 case LWS_PPS_HTTP2_ACK_SETTINGS:
 122                         lws_http2_do_pps_send(lws_get_context(wsi), wsi);
 123                         break;
 124                 default:
 125                         break;
 126                 }
 127                 wsi->pps = LWS_PPS_NONE;
 128                 lws_rx_flow_control(wsi, 1);
 129
 130                 goto bail_ok; /* leave POLLOUT active */
 131         }
 132 #endif
 133
 134 #ifdef LWS_WITH_CGI
 135         if (wsi->cgi) {
 136                 /* also one shot */
 137                 if (pollfd)
 138                         if (lws_change_pollfd(wsi, LWS_POLLOUT, 0)) {
 139                                 lwsl_info("failed at set pollfd\n");
 140                                 return 1;
 141                         }
 142                 goto user_service_go_again;
 143         }
 144 #endif
 145
 146         /* Priority 3: pending control packets (pong or close)
 147          */
 148         if ((wsi->state == LWSS_ESTABLISHED &&
 149              wsi->u.ws.ping_pending_flag) ||
 150             (wsi->state == LWSS_RETURNED_CLOSE_ALREADY &&
 151              wsi->u.ws.payload_is_close)) {
 152
 153                 if (wsi->u.ws.payload_is_close)
 154                         write_type = LWS_WRITE_CLOSE;
 155
 156                 n = lws_write(wsi, &wsi->u.ws.ping_payload_buf[LWS_PRE],
 157                               wsi->u.ws.ping_payload_len, write_type);
 158                 if (n < 0)
 159                         goto bail_die;
 160
 161                 /* well he is sent, mark him done */
 162                 wsi->u.ws.ping_pending_flag = 0;
 163                 if (wsi->u.ws.payload_is_close)
 164                         /* oh... a close frame was it... then we are done */
 165                         goto bail_die;
 166
 167                 /* otherwise for PING, leave POLLOUT active either way */
 168                 goto bail_ok;
 169         }
 170
 171         if (wsi->state == LWSS_ESTABLISHED &&
 172             !wsi->socket_is_permanently_unusable &&
 173             wsi->u.ws.send_check_ping) {
 174
 175                 lwsl_info("issuing ping on wsi %p\n", wsi);
 176                 wsi->u.ws.send_check_ping = 0;
 177                 n = lws_write(wsi, &wsi->u.ws.ping_payload_buf[LWS_PRE],
 178                               0, LWS_WRITE_PING);
 179                 if (n < 0)
 180                         goto bail_die;
 181
 182                 /*
 183                  * we apparently were able to send the PING in a reasonable time
 184                  * now reset the clock on our peer to be able to send the
 185                  * PONG in a reasonable time.
 186                  */
 187
 188                 lws_set_timeout(wsi, PENDING_TIMEOUT_WS_PONG_CHECK_GET_PONG,
 189                                 wsi->context->timeout_secs);
 190
 191                 goto bail_ok;
 192         }
 193
 194         /* Priority 4: if we are closing, not allowed to send more data frags
 195          *             which means user callback or tx ext flush banned now
 196          */
 197         if (wsi->state == LWSS_RETURNED_CLOSE_ALREADY)
 198                 goto user_service;
 199
 200         /* Priority 5: Tx path extension with more to send
 201          *
 202          *             These are handled as new fragments each time around
 203          *             So while we must block new writeable callback to enforce
 204          *             payload ordering, but since they are always complete
 205          *             fragments control packets can interleave OK.
 206          */
 207         if (wsi->state == LWSS_ESTABLISHED && wsi->u.ws.tx_draining_ext) {
 208                 lwsl_ext("SERVICING TX EXT DRAINING\n");
 209                 if (lws_write(wsi, NULL, 0, LWS_WRITE_CONTINUATION) < 0)
 210                         goto bail_die;
 211                 /* leave POLLOUT active */
 212                 goto bail_ok;
 213         }
 214
 215         /* Priority 6: user can get the callback
 216          */
 217         m = lws_ext_cb_active(wsi, LWS_EXT_CB_IS_WRITEABLE, NULL, 0);
 218         if (m)
 219                 goto bail_die;
 220 #ifndef LWS_NO_EXTENSIONS
 221         if (!wsi->extension_data_pending)
 222                 goto user_service;
 223 #endif
 224         /*
 225          * check in on the active extensions, see if they
 226          * had pending stuff to spill... they need to get the
 227          * first look-in otherwise sequence will be disordered
 228          *
 229          * NULL, zero-length eff_buf means just spill pending
 230          */
 231
 232         ret = 1;
 233         if (wsi->mode == LWSCM_RAW || wsi->mode == LWSCM_RAW_FILEDESC)
 234                 ret = 0;
 235         while (ret == 1) {
 236
 237                 /* default to nobody has more to spill */
 238
 239                 ret = 0;
 240                 eff_buf.token = NULL;
 241                 eff_buf.token_len = 0;
 242
 243                 /* give every extension a chance to spill */
 244
 245                 m = lws_ext_cb_active(wsi,
 246                                         LWS_EXT_CB_PACKET_TX_PRESEND,
 247                                                &eff_buf, 0);
 248                 if (m < 0) {
 249                         lwsl_err("ext reports fatal error\n");
 250                         goto bail_die;
 251                 }
 252                 if (m)
 253                         /*
 254                          * at least one extension told us he has more
 255                          * to spill, so we will go around again after
 256                          */
 257                         ret = 1;
 258
 259                 /* assuming they gave us something to send, send it */
 260
 261                 if (eff_buf.token_len) {
 262                         n = lws_issue_raw(wsi, (unsigned char *)eff_buf.token,
 263                                           eff_buf.token_len);
 264                         if (n < 0) {
 265                                 lwsl_info("closing from POLLOUT spill\n");
 266                                 goto bail_die;
 267                         }
 268                         /*
 269                          * Keep amount spilled small to minimize chance of this
 270                          */
 271                         if (n != eff_buf.token_len) {
 272                                 lwsl_err("Unable to spill ext %d vs %d\n",
 273                                                           eff_buf.token_len, n);
 274                                 goto bail_die;
 275                         }
 276                 } else
 277                         continue;
 278
 279                 /* no extension has more to spill */
 280
 281                 if (!ret)
 282                         continue;
 283
 284                 /*
 285                  * There's more to spill from an extension, but we just sent
 286                  * something... did that leave the pipe choked?
 287                  */
 288
 289                 if (!lws_send_pipe_choked(wsi))
 290                         /* no we could add more */
 291                         continue;
 292
 293                 lwsl_info("choked in POLLOUT service\n");
 294
 295                 /*
 296                  * Yes, he's choked.  Leave the POLLOUT masked on so we will
 297                  * come back here when he is unchoked.  Don't call the user
 298                  * callback to enforce ordering of spilling, he'll get called
 299                  * when we come back here and there's nothing more to spill.
 300                  */
 301
 302                 goto bail_ok;
 303         }
 304 #ifndef LWS_NO_EXTENSIONS
 305         wsi->extension_data_pending = 0;
 306 #endif
 307 user_service:
 308         /* one shot */
 309
 310         if (pollfd) {
 311                 int eff = wsi->leave_pollout_active;
 312
 313                 if (!eff)
 314                         if (lws_change_pollfd(wsi, LWS_POLLOUT, 0)) {
 315                                 lwsl_info("failed at set pollfd\n");
 316                                 goto bail_die;
 317                         }
 318
 319                 wsi->handling_pollout = 0;
 320
 321                 /* cannot get leave_pollout_active set after the above */
 322
 323                 if (!eff && wsi->leave_pollout_active)
 324                         /* got set inbetween sampling eff and clearing
 325                          * handling_pollout, force POLLOUT on */
 326                         lws_calllback_as_writeable(wsi);
 327
 328                 wsi->leave_pollout_active = 0;
 329         }
 330
 331         if (wsi->mode != LWSCM_WSCL_ISSUE_HTTP_BODY &&
 332             !wsi->hdr_parsing_completed)
 333                 goto bail_ok;
 334
 335
 336 #ifdef LWS_WITH_CGI
 337 user_service_go_again:
 338 #endif
 339
 340 #ifdef LWS_USE_HTTP2
 341         /*
 342          * we are the 'network wsi' for potentially many muxed child wsi with
 343          * no network connection of their own, who have to use us for all their
 344          * network actions.  So we use a round-robin scheme to share out the
 345          * POLLOUT notifications to our children.
 346          *
 347          * But because any child could exhaust the socket's ability to take
 348          * writes, we can only let one child get notified each time.
 349          *
 350          * In addition children may be closed / deleted / added between POLLOUT
 351          * notifications, so we can't hold pointers
 352          */
 353
 354         if (wsi->mode != LWSCM_HTTP2_SERVING) {
 355                 lwsl_info("%s: non http2\n", __func__);
 356                 goto notify;
 357         }
 358
 359         wsi->u.http2.requested_POLLOUT = 0;
 360         if (!wsi->u.http2.initialized) {
 361                 lwsl_info("pollout on uninitialized http2 conn\n");
 362                 goto bail_ok;
 363         }
 364
 365         lwsl_info("%s: doing children\n", __func__);
 366
 367         wsi2 = wsi;
 368         do {
 369                 wsi2 = wsi2->u.http2.next_child_wsi;
 370                 lwsl_info("%s: child %p\n", __func__, wsi2);
 371                 if (!wsi2)
 372                         continue;
 373                 if (!wsi2->u.http2.requested_POLLOUT)
 374                         continue;
 375                 wsi2->u.http2.requested_POLLOUT = 0;
 376                 if (lws_calllback_as_writeable(wsi2)) {
 377                         lwsl_debug("Closing POLLOUT child\n");
 378                         lws_close_free_wsi(wsi2, LWS_CLOSE_STATUS_NOSTATUS);
 379                 }
 380                 wsi2 = wsi;
 381         } while (wsi2 != NULL && !lws_send_pipe_choked(wsi));
 382
 383         lwsl_info("%s: completed\n", __func__);
 384
 385         goto bail_ok;
 386 notify:
 387 #endif
 388         wsi->handling_pollout = 0;
 389         wsi->leave_pollout_active = 0;
 390
 391         return lws_calllback_as_writeable(wsi);
 392
 393         /*
 394          * since these don't disable the POLLOUT, they are always doing the
 395          * right thing for leave_pollout_active whether it was set or not.
 396          */
 397
 398 bail_ok:
 399         wsi->handling_pollout = 0;
 400         wsi->leave_pollout_active = 0;
 401
 402         return 0;
 403
 404 bail_die:
 405         wsi->handling_pollout = 0;
 406         wsi->leave_pollout_active = 0;
 407
 408         return -1;
 409 }
 410
 411 int
 412 lws_service_timeout_check(struct lws *wsi, unsigned int sec)
 413 {
 414 //#if LWS_POSIX
 415         struct lws_context_per_thread *pt = &wsi->context->pt[(int)wsi->tsi];
 416         int n = 0;
 417 //#endif
 418
 419         (void)n;
 420
 421         /*
 422          * if extensions want in on it (eg, we are a mux parent)
 423          * give them a chance to service child timeouts
 424          */
 425         if (lws_ext_cb_active(wsi, LWS_EXT_CB_1HZ, NULL, sec) < 0)
 426                 return 0;
 427
 428         if (!wsi->pending_timeout)
 429                 return 0;
 430
 431         /*
 432          * if we went beyond the allowed time, kill the
 433          * connection
 434          */
 435         if ((time_t)sec > wsi->pending_timeout_limit) {
 436 //#if LWS_POSIX
 437                 if (wsi->desc.sockfd != LWS_SOCK_INVALID && wsi->position_in_fds_table >= 0)
 438                         n = pt->fds[wsi->position_in_fds_table].events;
 439
 440                 lws_stats_atomic_bump(wsi->context, pt, LWSSTATS_C_TIMEOUTS, 1);
 441
 442                 /* no need to log normal idle keepalive timeout */
 443                 if (wsi->pending_timeout != PENDING_TIMEOUT_HTTP_KEEPALIVE_IDLE)
 444                         lwsl_notice("wsi %p: TIMEDOUT WAITING on %d (did hdr %d, ah %p, wl %d, pfd events %d) %llu vs %llu\n",
 445                             (void *)wsi, wsi->pending_timeout,
 446                             wsi->hdr_parsing_completed, wsi->u.hdr.ah,
 447                             pt->ah_wait_list_length, n, (unsigned long long)sec, (unsigned long long)wsi->pending_timeout_limit);
 448 //#endif
 449                 /*
 450                  * Since he failed a timeout, he already had a chance to do
 451                  * something and was unable to... that includes situations like
 452                  * half closed connections.  So process this "failed timeout"
 453                  * close as a violent death and don't try to do protocol
 454                  * cleanup like flush partials.
 455                  */
 456                 wsi->socket_is_permanently_unusable = 1;
 457                 if (wsi->mode == LWSCM_WSCL_WAITING_SSL)
 458                         wsi->vhost->protocols[0].callback(wsi,
 459                                 LWS_CALLBACK_CLIENT_CONNECTION_ERROR,
 460                                 wsi->user_space, (void *)"Timed out waiting SSL", 21);
 461
 462                 lws_close_free_wsi(wsi, LWS_CLOSE_STATUS_NOSTATUS);
 463
 464                 return 1;
 465         }
 466
 467         return 0;
 468 }
 469
 470 int lws_rxflow_cache(struct lws *wsi, unsigned char *buf, int n, int len)
 471 {
 472         /* his RX is flowcontrolled, don't send remaining now */
 473         if (wsi->rxflow_buffer) {
 474                 /* rxflow while we were spilling prev rxflow */
 475                 lwsl_info("stalling in existing rxflow buf\n");
 476                 return 1;
 477         }
 478
 479         /* a new rxflow, buffer it and warn caller */
 480         lwsl_info("new rxflow input buffer len %d\n", len - n);
 481         wsi->rxflow_buffer = lws_malloc(len - n);
 482         if (!wsi->rxflow_buffer)
 483                 return -1;
 484         wsi->rxflow_len = len - n;
 485         wsi->rxflow_pos = 0;
 486         memcpy(wsi->rxflow_buffer, buf + n, len - n);
 487
 488         return 0;
 489 }
 490
 491 /* this is used by the platform service code to stop us waiting for network
 492  * activity in poll() when we have something that already needs service
 493  */
 494
 495 LWS_VISIBLE LWS_EXTERN int
 496 lws_service_adjust_timeout(struct lws_context *context, int timeout_ms, int tsi)
 497 {
 498         struct lws_context_per_thread *pt = &context->pt[tsi];
 499         int n;
 500
 501         /* Figure out if we really want to wait in poll()
 502          * We only need to wait if really nothing already to do and we have
 503          * to wait for something from network
 504          */
 505
 506         /* 1) if we know we are draining rx ext, do not wait in poll */
 507         if (pt->rx_draining_ext_list)
 508                 return 0;
 509
 510 #ifdef LWS_OPENSSL_SUPPORT
 511         /* 2) if we know we have non-network pending data, do not wait in poll */
 512         if (lws_ssl_anybody_has_buffered_read_tsi(context, tsi)) {
 513                 lwsl_info("ssl buffered read\n");
 514                 return 0;
 515         }
 516 #endif
 517
 518         /* 3) if any ah has pending rx, do not wait in poll */
 519         for (n = 0; n < context->max_http_header_pool; n++)
 520                 if (pt->ah_pool[n].rxpos != pt->ah_pool[n].rxlen) {
 521                         /* any ah with pending rx must be attached to someone */
 522                         if (!pt->ah_pool[n].wsi) {
 523                                 lwsl_err("%s: assert: no wsi attached to ah\n", __func__);
 524                                 assert(0);
 525                         }
 526                         return 0;
 527                 }
 528
 529         return timeout_ms;
 530 }
 531
 532 /*
 533  * guys that need POLLIN service again without waiting for network action
 534  * can force POLLIN here if not flowcontrolled, so they will get service.
 535  *
 536  * Return nonzero if anybody got their POLLIN faked
 537  */
 538 int
 539 lws_service_flag_pending(struct lws_context *context, int tsi)
 540 {
 541         struct lws_context_per_thread *pt = &context->pt[tsi];
 542 #ifdef LWS_OPENSSL_SUPPORT
 543         struct lws *wsi_next;
 544 #endif
 545         struct lws *wsi;
 546         int forced = 0;
 547         int n;
 548
 549         /* POLLIN faking */
 550
 551         /*
 552          * 1) For all guys with already-available ext data to drain, if they are
 553          * not flowcontrolled, fake their POLLIN status
 554          */
 555         wsi = pt->rx_draining_ext_list;
 556         while (wsi) {
 557                 pt->fds[wsi->position_in_fds_table].revents |=
 558                         pt->fds[wsi->position_in_fds_table].events & LWS_POLLIN;
 559                 if (pt->fds[wsi->position_in_fds_table].revents & LWS_POLLIN) {
 560                         forced = 1;
 561                         break;
 562                 }
 563                 wsi = wsi->u.ws.rx_draining_ext_list;
 564         }
 565
 566 #ifdef LWS_OPENSSL_SUPPORT
 567         /*
 568          * 2) For all guys with buffered SSL read data already saved up, if they
 569          * are not flowcontrolled, fake their POLLIN status so they'll get
 570          * service to use up the buffered incoming data, even though their
 571          * network socket may have nothing
 572          */
 573         wsi = pt->pending_read_list;
 574         while (wsi) {
 575                 wsi_next = wsi->pending_read_list_next;
 576                 pt->fds[wsi->position_in_fds_table].revents |=
 577                         pt->fds[wsi->position_in_fds_table].events & LWS_POLLIN;
 578                 if (pt->fds[wsi->position_in_fds_table].revents & LWS_POLLIN) {
 579                         forced = 1;
 580                         /*
 581                          * he's going to get serviced now, take him off the
 582                          * list of guys with buffered SSL.  If he still has some
 583                          * at the end of the service, he'll get put back on the
 584                          * list then.
 585                          */
 586                         lws_ssl_remove_wsi_from_buffered_list(wsi);
 587                 }
 588
 589                 wsi = wsi_next;
 590         }
 591 #endif
 592         /*
 593          * 3) For any wsi who have an ah with pending RX who did not
 594          * complete their current headers, and are not flowcontrolled,
 595          * fake their POLLIN status so they will be able to drain the
 596          * rx buffered in the ah
 597          */
 598         for (n = 0; n < context->max_http_header_pool; n++)
 599                 if (pt->ah_pool[n].rxpos != pt->ah_pool[n].rxlen &&
 600                     !pt->ah_pool[n].wsi->hdr_parsing_completed) {
 601                         pt->fds[pt->ah_pool[n].wsi->position_in_fds_table].revents |=
 602                                 pt->fds[pt->ah_pool[n].wsi->position_in_fds_table].events &
 603                                         LWS_POLLIN;
 604                         if (pt->fds[pt->ah_pool[n].wsi->position_in_fds_table].revents &
 605                             LWS_POLLIN)
 606                                 forced = 1;
 607                 }
 608
 609         return forced;
 610 }
 611
 612 #ifndef LWS_NO_CLIENT
 613
 614 LWS_VISIBLE int
 615 lws_http_client_read(struct lws *wsi, char **buf, int *len)
 616 {
 617         int rlen, n;
 618
 619         rlen = lws_ssl_capable_read(wsi, (unsigned char *)*buf, *len);
 620         *len = 0;
 621
 622         /* allow the source to signal he has data again next time */
 623         lws_change_pollfd(wsi, 0, LWS_POLLIN);
 624
 625         if (rlen == LWS_SSL_CAPABLE_ERROR) {
 626                 lwsl_notice("%s: SSL capable error\n", __func__);
 627                 return -1;
 628         }
 629
 630         if (rlen == 0)
 631                 return -1;
 632
 633         if (rlen < 0)
 634                 return 0;
 635
 636         *len = rlen;
 637         wsi->client_rx_avail = 0;
 638
 639         /*
 640          * server may insist on transfer-encoding: chunked,
 641          * so http client must deal with it
 642          */
 643 spin_chunks:
 644         while (wsi->chunked && (wsi->chunk_parser != ELCP_CONTENT) && *len) {
 645                 switch (wsi->chunk_parser) {
 646                 case ELCP_HEX:
 647                         if ((*buf)[0] == '\x0d') {
 648                                 wsi->chunk_parser = ELCP_CR;
 649                                 break;
 650                         }
 651                         n = char_to_hex((*buf)[0]);
 652                         if (n < 0) {
 653                                 lwsl_debug("chunking failure\n");
 654                                 return -1;
 655                         }
 656                         wsi->chunk_remaining <<= 4;
 657                         wsi->chunk_remaining |= n;
 658                         break;
 659                 case ELCP_CR:
 660                         if ((*buf)[0] != '\x0a') {
 661                                 lwsl_debug("chunking failure\n");
 662                                 return -1;
 663                         }
 664                         wsi->chunk_parser = ELCP_CONTENT;
 665                         lwsl_info("chunk %d\n", wsi->chunk_remaining);
 666                         if (wsi->chunk_remaining)
 667                                 break;
 668                         lwsl_info("final chunk\n");
 669                         goto completed;
 670
 671                 case ELCP_CONTENT:
 672                         break;
 673
 674                 case ELCP_POST_CR:
 675                         if ((*buf)[0] != '\x0d') {
 676                                 lwsl_debug("chunking failure\n");
 677
 678                                 return -1;
 679                         }
 680
 681                         wsi->chunk_parser = ELCP_POST_LF;
 682                         break;
 683
 684                 case ELCP_POST_LF:
 685                         if ((*buf)[0] != '\x0a')
 686                                 return -1;
 687
 688                         wsi->chunk_parser = ELCP_HEX;
 689                         wsi->chunk_remaining = 0;
 690                         break;
 691                 }
 692                 (*buf)++;
 693                 (*len)--;
 694         }
 695
 696         if (wsi->chunked && !wsi->chunk_remaining)
 697                 return 0;
 698
 699         if (wsi->u.http.content_remain &&
 700             wsi->u.http.content_remain < *len)
 701                 n = (int)wsi->u.http.content_remain;
 702         else
 703                 n = *len;
 704
 705         if (wsi->chunked && wsi->chunk_remaining &&
 706             wsi->chunk_remaining < n)
 707                 n = wsi->chunk_remaining;
 708
 709 #ifdef LWS_WITH_HTTP_PROXY
 710         /* hubbub */
 711         if (wsi->perform_rewrite)
 712                 lws_rewrite_parse(wsi->rw, (unsigned char *)*buf, n);
 713         else
 714 #endif
 715                 if (user_callback_handle_rxflow(wsi->protocol->callback,
 716                                 wsi, LWS_CALLBACK_RECEIVE_CLIENT_HTTP_READ,
 717                                 wsi->user_space, *buf, n)) {
 718                         lwsl_debug("%s: LWS_CALLBACK_RECEIVE_CLIENT_HTTP_READ returned -1\n", __func__);
 719
 720                         return -1;
 721                 }
 722
 723         if (wsi->chunked && wsi->chunk_remaining) {
 724                 (*buf) += n;
 725                 wsi->chunk_remaining -= n;
 726                 *len -= n;
 727         }
 728
 729         if (wsi->chunked && !wsi->chunk_remaining)
 730                 wsi->chunk_parser = ELCP_POST_CR;
 731
 732         if (wsi->chunked && *len)
 733                 goto spin_chunks;
 734
 735         if (wsi->chunked)
 736                 return 0;
 737
 738         /* if we know the content length, decrement the content remaining */
 739         if (wsi->u.http.content_length > 0)
 740                 wsi->u.http.content_remain -= n;
 741
 742         if (wsi->u.http.content_remain || !wsi->u.http.content_length)
 743                 return 0;
 744
 745 completed:
 746         if (user_callback_handle_rxflow(wsi->protocol->callback,
 747                         wsi, LWS_CALLBACK_COMPLETED_CLIENT_HTTP,
 748                         wsi->user_space, NULL, 0)) {
 749                 lwsl_debug("Completed call returned -1\n");
 750                 return -1;
 751         }
 752
 753         if (lws_http_transaction_completed_client(wsi)) {
 754                 lwsl_notice("%s: transaction completed says -1\n", __func__);
 755                 return -1;
 756         }
 757
 758         return 0;
 759 }
 760 #endif
 761
 762 static int
 763 lws_is_ws_with_ext(struct lws *wsi)
 764 {
 765 #if defined(LWS_NO_EXTENSIONS)
 766         return 0;
 767 #else
 768         return wsi->state == LWSS_ESTABLISHED &&
 769                !!wsi->count_act_ext;
 770 #endif
 771 }
 772
 773 LWS_VISIBLE int
 774 lws_service_fd_tsi(struct lws_context *context, struct lws_pollfd *pollfd, int tsi)
 775 {
 776         struct lws_context_per_thread *pt = &context->pt[tsi];
 777         lws_sockfd_type our_fd = 0, tmp_fd;
 778         struct lws_tokens eff_buf;
 779         unsigned int pending = 0;
 780         struct lws *wsi, *wsi1;
 781         char draining_flow = 0;
 782         int timed_out = 0;
 783         time_t now;
 784         int n = 0, m;
 785         int more;
 786
 787         if (!context->protocol_init_done)
 788                 lws_protocol_init(context);
 789
 790         time(&now);
 791
 792         /*
 793          * handle case that system time was uninitialized when lws started
 794          * at boot, and got initialized a little later
 795          */
 796         if (context->time_up < 1464083026 && now > 1464083026)
 797                 context->time_up = now;
 798
 799         /* TODO: if using libev, we should probably use timeout watchers... */
 800         if (context->last_timeout_check_s != now) {
 801                 context->last_timeout_check_s = now;
 802
 803 #if defined(LWS_WITH_STATS)
 804                 if (!tsi && now - context->last_dump > 10) {
 805                         lws_stats_log_dump(context);
 806                         context->last_dump = now;
 807                 }
 808 #endif
 809
 810                 lws_plat_service_periodic(context);
 811
 812                 lws_check_deferred_free(context, 0);
 813
 814                 /* retire unused deprecated context */
 815 #if !defined(LWS_PLAT_OPTEE) && !defined(LWS_WITH_ESP32)
 816 #if LWS_POSIX && !defined(_WIN32)
 817                 if (context->deprecated && !context->count_wsi_allocated) {
 818                         lwsl_notice("%s: ending deprecated context\n", __func__);
 819                         kill(getpid(), SIGINT);
 820                         return 0;
 821                 }
 822 #endif
 823 #endif
 824                 /* global timeout check once per second */
 825
 826                 if (pollfd)
 827                         our_fd = pollfd->fd;
 828
 829                 wsi = context->pt[tsi].timeout_list;
 830                 while (wsi) {
 831                         /* we have to take copies, because he may be deleted */
 832                         wsi1 = wsi->timeout_list;
 833                         tmp_fd = wsi->desc.sockfd;
 834                         if (lws_service_timeout_check(wsi, (unsigned int)now)) {
 835                                 /* he did time out... */
 836                                 if (tmp_fd == our_fd)
 837                                         /* it was the guy we came to service! */
 838                                         timed_out = 1;
 839                                         /* he's gone, no need to mark as handled */
 840                         }
 841                         wsi = wsi1;
 842                 }
 843 #ifdef LWS_WITH_CGI
 844                 lws_cgi_kill_terminated(pt);
 845 #endif
 846 #if 0
 847                 {
 848                         char s[300], *p = s;
 849
 850                         for (n = 0; n < context->count_threads; n++)
 851                                 p += sprintf(p, " %7lu (%5d), ",
 852                                              context->pt[n].count_conns,
 853                                              context->pt[n].fds_count);
 854
 855                         lwsl_notice("load: %s\n", s);
 856                 }
 857 #endif
 858         }
 859
 860         /*
 861          * at intervals, check for ws connections needing ping-pong checks
 862          */
 863
 864         if (context->ws_ping_pong_interval &&
 865             context->last_ws_ping_pong_check_s < now + 10) {
 866                 struct lws_vhost *vh = context->vhost_list;
 867                 context->last_ws_ping_pong_check_s = now;
 868
 869                 while (vh) {
 870                         for (n = 0; n < vh->count_protocols; n++) {
 871                                 wsi = vh->same_vh_protocol_list[n];
 872
 873                                 while (wsi) {
 874                                         if (wsi->state == LWSS_ESTABLISHED &&
 875                                             !wsi->socket_is_permanently_unusable &&
 876                                             !wsi->u.ws.send_check_ping &&
 877                                             wsi->u.ws.time_next_ping_check &&
 878                                             wsi->u.ws.time_next_ping_check < now) {
 879
 880                                                 lwsl_info("requesting ping-pong on wsi %p\n", wsi);
 881                                                 wsi->u.ws.send_check_ping = 1;
 882                                                 lws_set_timeout(wsi, PENDING_TIMEOUT_WS_PONG_CHECK_SEND_PING,
 883                                                                 context->timeout_secs);
 884                                                 lws_callback_on_writable(wsi);
 885                                                 wsi->u.ws.time_next_ping_check = now +
 886                                                                 wsi->context->ws_ping_pong_interval;
 887                                         }
 888                                         wsi = wsi->same_vh_protocol_next;
 889                                 }
 890                         }
 891                         vh = vh->vhost_next;
 892                 }
 893         }
 894
 895         /* the socket we came to service timed out, nothing to do */
 896         if (timed_out)
 897                 return 0;
 898
 899         /* just here for timeout management? */
 900         if (!pollfd)
 901                 return 0;
 902
 903         /* no, here to service a socket descriptor */
 904         wsi = wsi_from_fd(context, pollfd->fd);
 905         if (!wsi)
 906                 /* not lws connection ... leave revents alone and return */
 907                 return 0;
 908
 909         /*
 910          * so that caller can tell we handled, past here we need to
 911          * zero down pollfd->revents after handling
 912          */
 913
 914 #if LWS_POSIX
 915         /* handle session socket closed */
 916
 917         if ((!(pollfd->revents & pollfd->events & LWS_POLLIN)) &&
 918             (pollfd->revents & LWS_POLLHUP)) {
 919                 wsi->socket_is_permanently_unusable = 1;
 920                 lwsl_debug("Session Socket %p (fd=%d) dead\n",
 921                                                        (void *)wsi, pollfd->fd);
 922
 923                 goto close_and_handled;
 924         }
 925
 926 #ifdef _WIN32
 927         if (pollfd->revents & LWS_POLLOUT)
 928                 wsi->sock_send_blocking = FALSE;
 929 #endif
 930
 931 #endif
 932
 933 //       lwsl_debug("fd=%d, revents=%d, mode=%d, state=%d\n", pollfd->fd, pollfd->revents, (int)wsi->mode, (int)wsi->state);
 934         if (pollfd->revents & LWS_POLLHUP) {
 935                 lwsl_debug("pollhup\n");
 936                 wsi->socket_is_permanently_unusable = 1;
 937                 goto close_and_handled;
 938         }
 939
 940
 941 #ifdef LWS_OPENSSL_SUPPORT
 942         if ((wsi->state == LWSS_SHUTDOWN) && lws_is_ssl(wsi) && wsi->ssl)
 943         {
 944                 n = SSL_shutdown(wsi->ssl);
 945                 lwsl_debug("SSL_shutdown=%d for fd %d\n", n, wsi->desc.sockfd);
 946                 if (n == 1)
 947                 {
 948                         n = shutdown(wsi->desc.sockfd, SHUT_WR);
 949                         goto close_and_handled;
 950                 }
 951                 else if (n == 0)
 952                 {
 953                         lws_change_pollfd(wsi, LWS_POLLOUT, LWS_POLLIN);
 954                         n = 0;
 955                         goto handled;
 956                 }
 957                 else /* n < 0 */
 958                 {
 959                         int shutdown_error = SSL_get_error(wsi->ssl, n);
 960                         lwsl_debug("SSL_shutdown returned %d, SSL_get_error: %d\n", n, shutdown_error);
 961                         if (shutdown_error == SSL_ERROR_WANT_READ) {
 962                                 lws_change_pollfd(wsi, LWS_POLLOUT, LWS_POLLIN);
 963                                 n = 0;
 964                                 goto handled;
 965                         } else if (shutdown_error == SSL_ERROR_WANT_WRITE) {
 966                                 lws_change_pollfd(wsi, LWS_POLLOUT, LWS_POLLOUT);
 967                                 n = 0;
 968                                 goto handled;
 969                         }
 970
 971                         // actual error occurred, just close the connection
 972                         n = shutdown(wsi->desc.sockfd, SHUT_WR);
 973                         goto close_and_handled;
 974                 }
 975         }
 976 #endif
 977
 978         /* okay, what we came here to do... */
 979
 980         switch (wsi->mode) {
 981         case LWSCM_HTTP_SERVING:
 982         case LWSCM_HTTP_CLIENT:
 983         case LWSCM_HTTP_SERVING_ACCEPTED:
 984         case LWSCM_SERVER_LISTENER:
 985         case LWSCM_SSL_ACK_PENDING:
 986         case LWSCM_SSL_ACK_PENDING_RAW:
 987                 if (wsi->state == LWSS_CLIENT_HTTP_ESTABLISHED)
 988                         goto handled;
 989
 990 #ifdef LWS_WITH_CGI
 991                 if (wsi->cgi && (pollfd->revents & LWS_POLLOUT)) {
 992                         n = lws_handle_POLLOUT_event(wsi, pollfd);
 993                         if (n)
 994                                 goto close_and_handled;
 995                         goto handled;
 996                 }
 997 #endif
 998                 /* fallthru */
 999         case LWSCM_RAW:
1000                 n = lws_server_socket_service(context, wsi, pollfd);
1001                 if (n) /* closed by above */
1002                         return 1;
1003                 goto handled;
1004
1005         case LWSCM_RAW_FILEDESC:
1006
1007                 if (pollfd->revents & LWS_POLLOUT) {
1008                         n = lws_calllback_as_writeable(wsi);
1009                         if (lws_change_pollfd(wsi, LWS_POLLOUT, 0)) {
1010                                 lwsl_info("failed at set pollfd\n");
1011                                 return 1;
1012                         }
1013                         if (n)
1014                                 goto close_and_handled;
1015                 }
1016                 n = LWS_CALLBACK_RAW_RX;
1017                 if (wsi->mode == LWSCM_RAW_FILEDESC)
1018                         n = LWS_CALLBACK_RAW_RX_FILE;
1019
1020                 if (pollfd->revents & LWS_POLLIN) {
1021                         if (user_callback_handle_rxflow(
1022                                         wsi->protocol->callback,
1023                                         wsi, n,
1024                                         wsi->user_space, NULL, 0)) {
1025                                 lwsl_debug("raw rx callback closed it\n");
1026                                 goto close_and_handled;
1027                         }
1028                 }
1029
1030                 if (pollfd->revents & LWS_POLLHUP)
1031                         goto close_and_handled;
1032                 n = 0;
1033                 goto handled;
1034
1035         case LWSCM_WS_SERVING:
1036         case LWSCM_WS_CLIENT:
1037         case LWSCM_HTTP2_SERVING:
1038         case LWSCM_HTTP_CLIENT_ACCEPTED:
1039
1040                 /* 1: something requested a callback when it was OK to write */
1041
1042                 if ((pollfd->revents & LWS_POLLOUT) &&
1043                     ((wsi->state == LWSS_ESTABLISHED ||
1044                      wsi->state == LWSS_HTTP2_ESTABLISHED ||
1045                      wsi->state == LWSS_HTTP2_ESTABLISHED_PRE_SETTINGS ||
1046                      wsi->state == LWSS_RETURNED_CLOSE_ALREADY ||
1047                      wsi->state == LWSS_FLUSHING_STORED_SEND_BEFORE_CLOSE)) &&
1048                     lws_handle_POLLOUT_event(wsi, pollfd)) {
1049                         if (wsi->state == LWSS_RETURNED_CLOSE_ALREADY)
1050                                 wsi->state = LWSS_FLUSHING_STORED_SEND_BEFORE_CLOSE;
1051                         lwsl_info("lws_service_fd: closing\n");
1052                         goto close_and_handled;
1053                 }
1054
1055                 if (wsi->state == LWSS_RETURNED_CLOSE_ALREADY ||
1056                     wsi->state == LWSS_AWAITING_CLOSE_ACK) {
1057                         /*
1058                          * we stopped caring about anything except control
1059                          * packets.  Force flow control off, defeat tx
1060                          * draining.
1061                          */
1062                         lws_rx_flow_control(wsi, 1);
1063                         wsi->u.ws.tx_draining_ext = 0;
1064                 }
1065
1066                 if (wsi->u.ws.tx_draining_ext)
1067                         /* we cannot deal with new RX until the TX ext
1068                          * path has been drained.  It's because new
1069                          * rx will, eg, crap on the wsi rx buf that
1070                          * may be needed to retain state.
1071                          *
1072                          * TX ext drain path MUST go through event loop
1073                          * to avoid blocking.
1074                          */
1075                         break;
1076
1077                 if (!(wsi->rxflow_change_to & LWS_RXFLOW_ALLOW))
1078                         /* We cannot deal with any kind of new RX
1079                          * because we are RX-flowcontrolled.
1080                          */
1081                         break;
1082
1083                 /* 2: RX Extension needs to be drained
1084                  */
1085
1086                 if (wsi->state == LWSS_ESTABLISHED &&
1087                     wsi->u.ws.rx_draining_ext) {
1088
1089                         lwsl_ext("%s: RX EXT DRAINING: Service\n", __func__);
1090 #ifndef LWS_NO_CLIENT
1091                         if (wsi->mode == LWSCM_WS_CLIENT) {
1092                                 n = lws_client_rx_sm(wsi, 0);
1093                                 if (n < 0)
1094                                         /* we closed wsi */
1095                                         n = 0;
1096                         } else
1097 #endif
1098                                 n = lws_rx_sm(wsi, 0);
1099
1100                         goto handled;
1101                 }
1102
1103                 if (wsi->u.ws.rx_draining_ext)
1104                         /*
1105                          * We have RX EXT content to drain, but can't do it
1106                          * right now.  That means we cannot do anything lower
1107                          * priority either.
1108                          */
1109                         break;
1110
1111                 /* 3: RX Flowcontrol buffer needs to be drained
1112                  */
1113
1114                 if (wsi->rxflow_buffer) {
1115                         lwsl_info("draining rxflow (len %d)\n",
1116                                 wsi->rxflow_len - wsi->rxflow_pos
1117                         );
1118                         /* well, drain it */
1119                         eff_buf.token = (char *)wsi->rxflow_buffer +
1120                                                 wsi->rxflow_pos;
1121                         eff_buf.token_len = wsi->rxflow_len - wsi->rxflow_pos;
1122                         draining_flow = 1;
1123                         goto drain;
1124                 }
1125
1126                 /* 4: any incoming (or ah-stashed incoming rx) data ready?
1127                  * notice if rx flow going off raced poll(), rx flow wins
1128                  */
1129
1130                 if (!(pollfd->revents & pollfd->events & LWS_POLLIN))
1131                         break;
1132
1133 read:
1134                 /* all the union members start with hdr, so even in ws mode
1135                  * we can deal with the ah via u.hdr
1136                  */
1137                 if (wsi->u.hdr.ah) {
1138                         lwsl_info("%s: %p: inherited ah rx\n", __func__, wsi);
1139                         eff_buf.token_len = wsi->u.hdr.ah->rxlen -
1140                                             wsi->u.hdr.ah->rxpos;
1141                         eff_buf.token = (char *)wsi->u.hdr.ah->rx +
1142                                         wsi->u.hdr.ah->rxpos;
1143                 } else {
1144                         if (wsi->mode != LWSCM_HTTP_CLIENT_ACCEPTED) {
1145                                 /*
1146                                  * extension may not consume everything (eg, pmd may be constrained
1147                                  * as to what it can output...) has to go in per-wsi rx buf area.
1148                                  * Otherwise in large temp serv_buf area.
1149                                  */
1150                                 eff_buf.token = (char *)pt->serv_buf;
1151                                 if (lws_is_ws_with_ext(wsi)) {
1152                                         eff_buf.token_len = wsi->u.ws.rx_ubuf_alloc;
1153                                 } else {
1154                                         eff_buf.token_len = context->pt_serv_buf_size;
1155                                 }
1156
1157                                 if ((unsigned int)eff_buf.token_len > context->pt_serv_buf_size)
1158                                         eff_buf.token_len = context->pt_serv_buf_size;
1159
1160                                 eff_buf.token_len = lws_ssl_capable_read(wsi,
1161                                         (unsigned char *)eff_buf.token, pending ? pending :
1162                                         eff_buf.token_len);
1163                                 switch (eff_buf.token_len) {
1164                                 case 0:
1165                                         lwsl_info("%s: zero length read\n", __func__);
1166                                         goto close_and_handled;
1167                                 case LWS_SSL_CAPABLE_MORE_SERVICE:
1168                                         lwsl_info("SSL Capable more service\n");
1169                                         n = 0;
1170                                         goto handled;
1171                                 case LWS_SSL_CAPABLE_ERROR:
1172                                         lwsl_info("Closing when error\n");
1173                                         goto close_and_handled;
1174                                 }
1175                                 // lwsl_notice("Actual RX %d\n", eff_buf.token_len);
1176                         }
1177                 }
1178
1179 drain:
1180 #ifndef LWS_NO_CLIENT
1181                 if (wsi->mode == LWSCM_HTTP_CLIENT_ACCEPTED &&
1182                     !wsi->told_user_closed) {
1183
1184                         /*
1185                          * In SSL mode we get POLLIN notification about
1186                          * encrypted data in.
1187                          *
1188                          * But that is not necessarily related to decrypted
1189                          * data out becoming available; in may need to perform
1190                          * other in or out before that happens.
1191                          *
1192                          * simply mark ourselves as having readable data
1193                          * and turn off our POLLIN
1194                          */
1195                         wsi->client_rx_avail = 1;
1196                         lws_change_pollfd(wsi, LWS_POLLIN, 0);
1197
1198                         /* let user code know, he'll usually ask for writeable
1199                          * callback and drain / re-enable it there
1200                          */
1201                         if (user_callback_handle_rxflow(
1202                                         wsi->protocol->callback,
1203                                         wsi, LWS_CALLBACK_RECEIVE_CLIENT_HTTP,
1204                                         wsi->user_space, NULL, 0)) {
1205                                 lwsl_notice("LWS_CALLBACK_RECEIVE_CLIENT_HTTP closed it\n");
1206                                 goto close_and_handled;
1207                         }
1208
1209                         n = 0;
1210                         goto handled;
1211                 }
1212 #endif
1213                 /*
1214                  * give any active extensions a chance to munge the buffer
1215                  * before parse.  We pass in a pointer to an lws_tokens struct
1216                  * prepared with the default buffer and content length that's in
1217                  * there.  Rather than rewrite the default buffer, extensions
1218                  * that expect to grow the buffer can adapt .token to
1219                  * point to their own per-connection buffer in the extension
1220                  * user allocation.  By default with no extensions or no
1221                  * extension callback handling, just the normal input buffer is
1222                  * used then so it is efficient.
1223                  */
1224                 do {
1225                         more = 0;
1226
1227                         m = lws_ext_cb_active(wsi, LWS_EXT_CB_PACKET_RX_PREPARSE,
1228                                               &eff_buf, 0);
1229                         if (m < 0)
1230                                 goto close_and_handled;
1231                         if (m)
1232                                 more = 1;
1233
1234                         /* service incoming data */
1235
1236                         if (eff_buf.token_len) {
1237                                 /*
1238                                  * if draining from rxflow buffer, not
1239                                  * critical to track what was used since at the
1240                                  * use it bumps wsi->rxflow_pos.  If we come
1241                                  * around again it will pick up from where it
1242                                  * left off.
1243                                  */
1244                                 // lwsl_notice("doing lws_read from pt->serv_buf %p %p for len %d\n", pt->serv_buf, eff_buf.token, (int)eff_buf.token_len);
1245
1246                                 n = lws_read(wsi, (unsigned char *)eff_buf.token,
1247                                              eff_buf.token_len);
1248                                 if (n < 0) {
1249                                         /* we closed wsi */
1250                                         n = 0;
1251                                         goto handled;
1252                                 }
1253                         }
1254
1255                         eff_buf.token = NULL;
1256                         eff_buf.token_len = 0;
1257                 } while (more);
1258
1259                 if (wsi->u.hdr.ah) {
1260                         lwsl_notice("%s: %p: detaching\n",
1261                                  __func__, wsi);
1262                         lws_header_table_force_to_detachable_state(wsi);
1263                         /* we can run the normal ah detach flow despite
1264                          * being in ws union mode, since all union members
1265                          * start with hdr */
1266                         lws_header_table_detach(wsi, 0);
1267                 }
1268
1269                 pending = lws_ssl_pending(wsi);
1270                 if (pending) {
1271                         if (lws_is_ws_with_ext(wsi))
1272                                 pending = pending > wsi->u.ws.rx_ubuf_alloc ?
1273                                         wsi->u.ws.rx_ubuf_alloc : pending;
1274                         else
1275                                 pending = pending > context->pt_serv_buf_size ?
1276                                         context->pt_serv_buf_size : pending;
1277                         goto read;
1278                 }
1279
1280                 if (draining_flow && wsi->rxflow_buffer &&
1281                     wsi->rxflow_pos == wsi->rxflow_len) {
1282                         lwsl_info("flow buffer: drained\n");
1283                         lws_free_set_NULL(wsi->rxflow_buffer);
1284                         /* having drained the rxflow buffer, can rearm POLLIN */
1285 #ifdef LWS_NO_SERVER
1286                         n =
1287 #endif
1288                         _lws_rx_flow_control(wsi);
1289                         /* n ignored, needed for NO_SERVER case */
1290                 }
1291
1292                 break;
1293 #ifdef LWS_WITH_CGI
1294         case LWSCM_CGI: /* we exist to handle a cgi's stdin/out/err data...
1295                          * do the callback on our master wsi
1296                          */
1297                 {
1298                         struct lws_cgi_args args;
1299
1300                         if (wsi->cgi_channel >= LWS_STDOUT &&
1301                             !(pollfd->revents & pollfd->events & LWS_POLLIN))
1302                                 break;
1303                         if (wsi->cgi_channel == LWS_STDIN &&
1304                             !(pollfd->revents & pollfd->events & LWS_POLLOUT))
1305                                 break;
1306
1307                         if (wsi->cgi_channel == LWS_STDIN)
1308                                 if (lws_change_pollfd(wsi, LWS_POLLOUT, 0)) {
1309                                         lwsl_info("failed at set pollfd\n");
1310                                         return 1;
1311                                 }
1312
1313                         args.ch = wsi->cgi_channel;
1314                         args.stdwsi = &wsi->parent->cgi->stdwsi[0];
1315                         args.hdr_state = wsi->hdr_state;
1316
1317                         //lwsl_err("CGI LWS_STDOUT waiting wsi %p mode %d state %d\n",
1318                         //       wsi->parent, wsi->parent->mode, wsi->parent->state);
1319
1320                         if (user_callback_handle_rxflow(
1321                                         wsi->parent->protocol->callback,
1322                                         wsi->parent, LWS_CALLBACK_CGI,
1323                                         wsi->parent->user_space,
1324                                         (void *)&args, 0))
1325                                 return 1;
1326
1327                         break;
1328                 }
1329 #endif
1330         default:
1331 #ifdef LWS_NO_CLIENT
1332                 break;
1333 #else
1334                 if ((pollfd->revents & LWS_POLLOUT) &&
1335                     lws_handle_POLLOUT_event(wsi, pollfd)) {
1336                         lwsl_debug("POLLOUT event closed it\n");
1337                         goto close_and_handled;
1338                 }
1339
1340                 n = lws_client_socket_service(context, wsi, pollfd);
1341                 if (n)
1342                         return 1;
1343                 goto handled;
1344 #endif
1345         }
1346
1347         n = 0;
1348         goto handled;
1349
1350 close_and_handled:
1351         lwsl_debug("%p: Close and handled\n", wsi);
1352         lws_close_free_wsi(wsi, LWS_CLOSE_STATUS_NOSTATUS);
1353         /*
1354          * pollfd may point to something else after the close
1355          * due to pollfd swapping scheme on delete on some platforms
1356          * we can't clear revents now because it'd be the wrong guy's revents
1357          */
1358         return 1;
1359
1360 handled:
1361         pollfd->revents = 0;
1362         return n;
1363 }
1364
1365 LWS_VISIBLE int
1366 lws_service_fd(struct lws_context *context, struct lws_pollfd *pollfd)
1367 {
1368         return lws_service_fd_tsi(context, pollfd, 0);
1369 }
1370
1371 LWS_VISIBLE int
1372 lws_service(struct lws_context *context, int timeout_ms)
1373 {
1374         return lws_plat_service(context, timeout_ms);
1375 }
1376
1377 LWS_VISIBLE int
1378 lws_service_tsi(struct lws_context *context, int timeout_ms, int tsi)
1379 {
1380         return _lws_plat_service_tsi(context, timeout_ms, tsi);
1381 }
1382