lwsws/http.c

   1 /*
   2  * libwebsockets web server application
   3  *
   4  * Copyright (C) 2010-2016 Andy Green <andy@warmcat.com>
   5  *
   6  * This program is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU 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  * General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU 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 #include "lwsws.h"
  22
  23 /* http server gets files from this path */
  24 #define LOCAL_RESOURCE_PATH INSTALL_DATADIR"/libwebsockets-test-server"
  25 char *resource_path = LOCAL_RESOURCE_PATH;
  26
  27
  28
  29 /*
  30  * We take a strict whitelist approach to stop ../ attacks
  31  */
  32 struct serveable {
  33         const char *urlpath;
  34         const char *mimetype;
  35 };
  36
  37 const char * get_mimetype(const char *file)
  38 {
  39         int n = strlen(file);
  40
  41         if (n < 5)
  42                 return NULL;
  43
  44         if (!strcmp(&file[n - 4], ".ico"))
  45                 return "image/x-icon";
  46
  47         if (!strcmp(&file[n - 4], ".png"))
  48                 return "image/png";
  49
  50         if (!strcmp(&file[n - 4], ".jpg"))
  51                 return "image/jpeg";
  52
  53         if (!strcmp(&file[n - 5], ".html"))
  54                 return "text/html";
  55
  56         if (!strcmp(&file[n - 4], ".css"))
  57                 return "text/css";
  58
  59         return NULL;
  60 }
  61
  62 /* this protocol server (always the first one) handles HTTP,
  63  *
  64  * Some misc callbacks that aren't associated with a protocol also turn up only
  65  * here on the first protocol server.
  66  */
  67
  68 int callback_http(struct lws *wsi, enum lws_callback_reasons reason, void *user,
  69                   void *in, size_t len)
  70 {
  71         struct per_session_data__http *pss =
  72                         (struct per_session_data__http *)user;
  73         unsigned char buffer[4096 + LWS_PRE];
  74         unsigned long amount, file_len, sent;
  75         char leaf_path[1024];
  76         const char *mimetype;
  77         char *other_headers;
  78         unsigned char *end;
  79         struct timeval tv;
  80         unsigned char *p;
  81 #ifndef LWS_NO_CLIENT
  82         struct per_session_data__http *pss1;
  83         struct lws *wsi1;
  84 #endif
  85         char buf[256];
  86         char b64[64];
  87         int n, m;
  88 #ifdef EXTERNAL_POLL
  89         struct lws_pollargs *pa = (struct lws_pollargs *)in;
  90 #endif
  91
  92 //      lwsl_err("%s: reason %d\n", __func__, reason);
  93
  94         switch (reason) {
  95         case LWS_CALLBACK_HTTP:
  96
  97                 {
  98                         char name[100], rip[50];
  99                         lws_get_peer_addresses(wsi, lws_get_socket_fd(wsi), name,
 100                                                sizeof(name), rip, sizeof(rip));
 101                         sprintf(buf, "%s (%s)", name, rip);
 102                         lwsl_notice("HTTP connect from %s\n", buf);
 103                 }
 104
 105                 if (len < 1) {
 106                         lws_return_http_status(wsi,
 107                                                 HTTP_STATUS_BAD_REQUEST, NULL);
 108                         goto try_to_reuse;
 109                 }
 110
 111 #ifndef LWS_NO_CLIENT
 112                 if (!strncmp(in, "/proxytest", 10)) {
 113                         struct lws_client_connect_info i;
 114                         char *rootpath = "/";
 115                         const char *p = (const char *)in;
 116
 117                         if (lws_get_child(wsi))
 118                                 break;
 119
 120                         pss->client_finished = 0;
 121                         memset(&i,0, sizeof(i));
 122                         i.context = lws_get_context(wsi);
 123                         i.address = "git.libwebsockets.org";
 124                         i.port = 80;
 125                         i.ssl_connection = 0;
 126                         if (p[10])
 127                                 i.path = (char *)in + 10;
 128                         else
 129                                 i.path = rootpath;
 130                         i.host = "git.libwebsockets.org";
 131                         i.origin = NULL;
 132                         i.method = "GET";
 133                         i.parent_wsi = wsi;
 134                         i.uri_replace_from = "git.libwebsockets.org/";
 135                         i.uri_replace_to = "/proxytest/";
 136                         if (!lws_client_connect_via_info(&i)) {
 137                                 lwsl_err("proxy connect fail\n");
 138                                 break;
 139                         }
 140
 141
 142
 143                         break;
 144                 }
 145 #endif
 146
 147 #if 1
 148                 /* this example server has no concept of directories */
 149                 if (strchr((const char *)in + 1, '/')) {
 150                         lws_return_http_status(wsi, HTTP_STATUS_FORBIDDEN, NULL);
 151                         goto try_to_reuse;
 152                 }
 153 #endif
 154
 155 #ifdef LWS_WITH_CGI
 156                 if (!strncmp(in, "/cgitest", 8)) {
 157                         static char *cmd[] = {
 158                                 "/bin/sh",
 159                                 "-c",
 160                                 INSTALL_DATADIR"/libwebsockets-test-server/lws-cgi-test.sh",
 161 //                              "/var/www/cgi-bin/cgit",
 162                                 NULL
 163                         };
 164
 165                         lwsl_notice("%s: cgitest\n", __func__);
 166                         n = lws_cgi(wsi, cmd, 8, 5);
 167                         if (n) {
 168                                 lwsl_err("%s: cgi failed\n");
 169                                 return -1;
 170                         }
 171                         p = buffer + LWS_PRE;
 172                         end = p + sizeof(buffer) - LWS_PRE;
 173
 174                         if (lws_add_http_header_status(wsi, 200, &p, end))
 175                                 return 1;
 176                         if (lws_add_http_header_by_token(wsi, WSI_TOKEN_CONNECTION,
 177                                         (unsigned char *)"close", 5, &p, end))
 178                                 return 1;
 179                         n = lws_write(wsi, buffer + LWS_PRE,
 180                                       p - (buffer + LWS_PRE),
 181                                       LWS_WRITE_HTTP_HEADERS);
 182
 183                         /* the cgi starts by outputting headers, we can't
 184                          *  finalize the headers until we see the end of that
 185                          */
 186
 187                         break;
 188                 }
 189 #endif
 190
 191                 /* if a legal POST URL, let it continue and accept data */
 192                 if (lws_hdr_total_length(wsi, WSI_TOKEN_POST_URI))
 193                         return 0;
 194
 195                 /* check for the "send a big file by hand" example case */
 196                 lwsl_notice("%s\n", in);
 197                 if (!strcmp((const char *)in, "/leaf.jpg")) {
 198                         if (strlen(resource_path) > sizeof(leaf_path) - 10)
 199                                 return -1;
 200                         sprintf(leaf_path, "%s/leaf.jpg", resource_path);
 201
 202                         /* well, let's demonstrate how to send the hard way */
 203
 204                         p = buffer + LWS_PRE;
 205                         end = p + sizeof(buffer) - LWS_PRE;
 206
 207                         pss->fd = lws_plat_file_open(wsi, leaf_path, &file_len,
 208                                                      LWS_O_RDONLY);
 209
 210                         if (pss->fd == LWS_INVALID_FILE) {
 211                                 lwsl_err("faild to open file %s\n", leaf_path);
 212                                 return -1;
 213                         }
 214
 215                         /*
 216                          * we will send a big jpeg file, but it could be
 217                          * anything.  Set the Content-Type: appropriately
 218                          * so the browser knows what to do with it.
 219                          *
 220                          * Notice we use the APIs to build the header, which
 221                          * will do the right thing for HTTP 1/1.1 and HTTP2
 222                          * depending on what connection it happens to be working
 223                          * on
 224                          */
 225                         if (lws_add_http_header_status(wsi, 200, &p, end))
 226                                 return 1;
 227                         if (lws_add_http_header_by_token(wsi, WSI_TOKEN_HTTP_SERVER,
 228                                         (unsigned char *)"libwebsockets",
 229                                         13, &p, end))
 230                                 return 1;
 231                         if (lws_add_http_header_by_token(wsi,
 232                                         WSI_TOKEN_HTTP_CONTENT_TYPE,
 233                                         (unsigned char *)"image/jpeg",
 234                                         10, &p, end))
 235                                 return 1;
 236                         if (lws_add_http_header_content_length(wsi,
 237                                                                file_len, &p,
 238                                                                end))
 239                                 return 1;
 240                         if (lws_finalize_http_header(wsi, &p, end))
 241                                 return 1;
 242
 243                         /*
 244                          * send the http headers...
 245                          * this won't block since it's the first payload sent
 246                          * on the connection since it was established
 247                          * (too small for partial)
 248                          *
 249                          * Notice they are sent using LWS_WRITE_HTTP_HEADERS
 250                          * which also means you can't send body too in one step,
 251                          * this is mandated by changes in HTTP2
 252                          */
 253
 254                         *p = '\0';
 255                         lwsl_info("%s\n", buffer + LWS_PRE);
 256
 257                         n = lws_write(wsi, buffer + LWS_PRE,
 258                                       p - (buffer + LWS_PRE),
 259                                       LWS_WRITE_HTTP_HEADERS);
 260                         if (n < 0) {
 261                                 lws_plat_file_close(wsi, pss->fd);
 262                                 return -1;
 263                         }
 264                         /*
 265                          * book us a LWS_CALLBACK_HTTP_WRITEABLE callback
 266                          */
 267                         lws_callback_on_writable(wsi);
 268                         break;
 269                 }
 270
 271                 /* if not, send a file the easy way */
 272                 if (!strncmp(in, "/cgit-data/", 11)) {
 273                         in = (char *)in + 11;
 274                         strcpy(buf, "/usr/share/cgit");
 275                 } else
 276                         strcpy(buf, resource_path);
 277
 278                 if (strcmp(in, "/")) {
 279                         if (*((const char *)in) != '/')
 280                                 strcat(buf, "/");
 281                         strncat(buf, in, sizeof(buf) - strlen(buf) - 1);
 282                 } else /* default file to serve */
 283                         strcat(buf, "/test.html");
 284                 buf[sizeof(buf) - 1] = '\0';
 285
 286                 /* refuse to serve files we don't understand */
 287                 mimetype = get_mimetype(buf);
 288                 if (!mimetype) {
 289                         lwsl_err("Unknown mimetype for %s\n", buf);
 290                         lws_return_http_status(wsi,
 291                                       HTTP_STATUS_UNSUPPORTED_MEDIA_TYPE, NULL);
 292                         return -1;
 293                 }
 294
 295                 /* demonstrates how to set a cookie on / */
 296
 297                 other_headers = leaf_path;
 298                 p = (unsigned char *)leaf_path;
 299                 if (!strcmp((const char *)in, "/") &&
 300                            !lws_hdr_total_length(wsi, WSI_TOKEN_HTTP_COOKIE)) {
 301                         /* this isn't very unguessable but it'll do for us */
 302                         gettimeofday(&tv, NULL);
 303                         n = sprintf(b64, "test=LWS_%u_%u_COOKIE;Max-Age=360000",
 304                                 (unsigned int)tv.tv_sec,
 305                                 (unsigned int)tv.tv_usec);
 306
 307                         if (lws_add_http_header_by_name(wsi,
 308                                 (unsigned char *)"set-cookie:",
 309                                 (unsigned char *)b64, n, &p,
 310                                 (unsigned char *)leaf_path + sizeof(leaf_path)))
 311                                 return 1;
 312                 }
 313                 if (lws_is_ssl(wsi) && lws_add_http_header_by_name(wsi,
 314                                                 (unsigned char *)
 315                                                 "Strict-Transport-Security:",
 316                                                 (unsigned char *)
 317                                                 "max-age=15768000 ; "
 318                                                 "includeSubDomains", 36, &p,
 319                                                 (unsigned char *)leaf_path +
 320                                                         sizeof(leaf_path)))
 321                         return 1;
 322                 n = (char *)p - leaf_path;
 323
 324                 n = lws_serve_http_file(wsi, buf, mimetype, other_headers, n);
 325                 if (n < 0 || ((n > 0) && lws_http_transaction_completed(wsi)))
 326                         return -1; /* error or can't reuse connection: close the socket */
 327
 328                 /*
 329                  * notice that the sending of the file completes asynchronously,
 330                  * we'll get a LWS_CALLBACK_HTTP_FILE_COMPLETION callback when
 331                  * it's done
 332                  */
 333                 break;
 334
 335         case LWS_CALLBACK_HTTP_BODY:
 336                 strncpy(buf, in, 20);
 337                 buf[20] = '\0';
 338                 if (len < 20)
 339                         buf[len] = '\0';
 340
 341                 lwsl_notice("LWS_CALLBACK_HTTP_BODY: %s... len %d\n",
 342                                 (const char *)buf, (int)len);
 343
 344                 break;
 345
 346         case LWS_CALLBACK_HTTP_BODY_COMPLETION:
 347                 lwsl_notice("LWS_CALLBACK_HTTP_BODY_COMPLETION\n");
 348                 /* the whole of the sent body arrived, close or reuse the connection */
 349                 lws_return_http_status(wsi, HTTP_STATUS_OK, NULL);
 350                 goto try_to_reuse;
 351
 352         case LWS_CALLBACK_HTTP_FILE_COMPLETION:
 353                 goto try_to_reuse;
 354
 355         case LWS_CALLBACK_HTTP_WRITEABLE:
 356                 lwsl_info("LWS_CALLBACK_HTTP_WRITEABLE\n");
 357
 358                 if (pss->client_finished)
 359                         return -1;
 360
 361                 if (pss->fd == LWS_INVALID_FILE)
 362                         goto try_to_reuse;
 363 #ifdef LWS_WITH_CGI
 364                 if (pss->reason_bf & 1) {
 365                         if (lws_cgi_write_split_stdout_headers(wsi) < 0)
 366                                 goto bail;
 367
 368                         pss->reason_bf &= ~1;
 369                         break;
 370                 }
 371 #endif
 372 #ifndef LWS_NO_CLIENT
 373                 if (pss->reason_bf & 2) {
 374                         char *px = buf + LWS_PRE;
 375                         int lenx = sizeof(buf) - LWS_PRE;
 376                         /*
 377                          * our sink is writeable and our source has something
 378                          * to read.  So read a lump of source material of
 379                          * suitable size to send or what's available, whichever
 380                          * is the smaller.
 381                          */
 382                         pss->reason_bf &= ~2;
 383                         wsi1 = lws_get_child(wsi);
 384                         if (!wsi1)
 385                                 break;
 386                         if (lws_http_client_read(wsi1, &px, &lenx) < 0)
 387                                 goto bail;
 388
 389                         if (pss->client_finished)
 390                                 return -1;
 391                         break;
 392                 }
 393 #endif
 394                 /*
 395                  * we can send more of whatever it is we were sending
 396                  */
 397                 sent = 0;
 398                 do {
 399                         /* we'd like the send this much */
 400                         n = sizeof(buffer) - LWS_PRE;
 401
 402                         /* but if the peer told us he wants less, we can adapt */
 403                         m = lws_get_peer_write_allowance(wsi);
 404
 405                         /* -1 means not using a protocol that has this info */
 406                         if (m == 0)
 407                                 /* right now, peer can't handle anything */
 408                                 goto later;
 409
 410                         if (m != -1 && m < n)
 411                                 /* he couldn't handle that much */
 412                                 n = m;
 413
 414                         n = lws_plat_file_read(wsi, pss->fd,
 415                                                &amount, buffer + LWS_PRE, n);
 416                         /* problem reading, close conn */
 417                         if (n < 0) {
 418                                 lwsl_err("problem reading file\n");
 419                                 goto bail;
 420                         }
 421                         n = (int)amount;
 422                         /* sent it all, close conn */
 423                         if (n == 0)
 424                                 goto penultimate;
 425                         /*
 426                          * To support HTTP2, must take care about preamble space
 427                          *
 428                          * identification of when we send the last payload frame
 429                          * is handled by the library itself if you sent a
 430                          * content-length header
 431                          */
 432                         m = lws_write(wsi, buffer + LWS_PRE, n, LWS_WRITE_HTTP);
 433                         if (m < 0) {
 434                                 lwsl_err("write failed\n");
 435                                 /* write failed, close conn */
 436                                 goto bail;
 437                         }
 438                         if (m) /* while still active, extend timeout */
 439                                 lws_set_timeout(wsi, PENDING_TIMEOUT_HTTP_CONTENT, 5);
 440                         sent += m;
 441
 442                 } while (!lws_send_pipe_choked(wsi) && (sent < 1024 * 1024));
 443 later:
 444                 lws_callback_on_writable(wsi);
 445                 break;
 446 penultimate:
 447                 lws_plat_file_close(wsi, pss->fd);
 448                 pss->fd = LWS_INVALID_FILE;
 449                 goto try_to_reuse;
 450
 451 bail:
 452                 lws_plat_file_close(wsi, pss->fd);
 453
 454                 return -1;
 455
 456         /*
 457          * callback for confirming to continue with client IP appear in
 458          * protocol 0 callback since no websocket protocol has been agreed
 459          * yet.  You can just ignore this if you won't filter on client IP
 460          * since the default unhandled callback return is 0 meaning let the
 461          * connection continue.
 462          */
 463         case LWS_CALLBACK_FILTER_NETWORK_CONNECTION:
 464                 /* if we returned non-zero from here, we kill the connection */
 465                 break;
 466
 467 #ifndef LWS_NO_CLIENT
 468         case LWS_CALLBACK_ESTABLISHED_CLIENT_HTTP: {
 469                 char ctype[64], ctlen = 0;
 470                 lwsl_err("LWS_CALLBACK_ESTABLISHED_CLIENT_HTTP\n");
 471                 p = buffer + LWS_PRE;
 472                 end = p + sizeof(buffer) - LWS_PRE;
 473                 if (lws_add_http_header_status(lws_get_parent(wsi), 200, &p, end))
 474                         return 1;
 475                 if (lws_add_http_header_by_token(lws_get_parent(wsi),
 476                                 WSI_TOKEN_HTTP_SERVER,
 477                                 (unsigned char *)"libwebsockets",
 478                                 13, &p, end))
 479                         return 1;
 480
 481                 ctlen = lws_hdr_copy(wsi, ctype, sizeof(ctype), WSI_TOKEN_HTTP_CONTENT_TYPE);
 482                 if (ctlen > 0) {
 483                         if (lws_add_http_header_by_token(lws_get_parent(wsi),
 484                                 WSI_TOKEN_HTTP_CONTENT_TYPE,
 485                                 (unsigned char *)ctype, ctlen, &p, end))
 486                                 return 1;
 487                 }
 488 #if 0
 489                 if (lws_add_http_header_content_length(lws_get_parent(wsi),
 490                                                        file_len, &p, end))
 491                         return 1;
 492 #endif
 493                 if (lws_finalize_http_header(lws_get_parent(wsi), &p, end))
 494                         return 1;
 495
 496                 *p = '\0';
 497                 lwsl_info("%s\n", buffer + LWS_PRE);
 498
 499                 n = lws_write(lws_get_parent(wsi), buffer + LWS_PRE,
 500                               p - (buffer + LWS_PRE),
 501                               LWS_WRITE_HTTP_HEADERS);
 502                 if (n < 0)
 503                         return -1;
 504
 505                 break; }
 506         case LWS_CALLBACK_CLOSED_CLIENT_HTTP:
 507                 //lwsl_err("LWS_CALLBACK_CLOSED_CLIENT_HTTP\n");
 508                 return -1;
 509                 break;
 510         case LWS_CALLBACK_RECEIVE_CLIENT_HTTP:
 511                 //lwsl_err("LWS_CALLBACK_RECEIVE_CLIENT_HTTP: wsi %p\n", wsi);
 512                 assert(lws_get_parent(wsi));
 513                 if (!lws_get_parent(wsi))
 514                         break;
 515                 // lwsl_err("LWS_CALLBACK_RECEIVE_CLIENT_HTTP: wsi %p: sock: %d, parent_wsi: %p, parent_sock:%d,  len %d\n",
 516                 //              wsi, lws_get_socket_fd(wsi),
 517                 //              lws_get_parent(wsi),
 518                 //              lws_get_socket_fd(lws_get_parent(wsi)), len);
 519                 pss1 = lws_wsi_user(lws_get_parent(wsi));
 520                 pss1->reason_bf |= 2;
 521                 lws_callback_on_writable(lws_get_parent(wsi));
 522                 break;
 523         case LWS_CALLBACK_RECEIVE_CLIENT_HTTP_READ:
 524                 //lwsl_err("LWS_CALLBACK_RECEIVE_CLIENT_HTTP_READ len %d\n", len);
 525                 assert(lws_get_parent(wsi));
 526                 m = lws_write(lws_get_parent(wsi), (unsigned char *)in,
 527                                 len, LWS_WRITE_HTTP);
 528                 if (m < 0)
 529                         return -1;
 530                 break;
 531         case LWS_CALLBACK_COMPLETED_CLIENT_HTTP:
 532                 //lwsl_err("LWS_CALLBACK_COMPLETED_CLIENT_HTTP\n");
 533                 assert(lws_get_parent(wsi));
 534                 if (!lws_get_parent(wsi))
 535                         break;
 536                 pss1 = lws_wsi_user(lws_get_parent(wsi));
 537                 pss1->client_finished = 1;
 538                 break;
 539 #endif
 540
 541 #ifdef LWS_WITH_CGI
 542         /* CGI IO events (POLLIN/OUT) appear here our demo user code policy is
 543          *
 544          *  - POST data goes on subprocess stdin
 545          *  - subprocess stdout goes on http via writeable callback
 546          *  - subprocess stderr goes to the logs
 547          */
 548         case LWS_CALLBACK_CGI:
 549                 pss->args = *((struct lws_cgi_args *)in);
 550                 //lwsl_notice("LWS_CALLBACK_CGI: ch %d\n", pss->args.ch);
 551                 switch (pss->args.ch) { /* which of stdin/out/err ? */
 552                 case LWS_STDIN:
 553                         /* TBD stdin rx flow control */
 554                         break;
 555                 case LWS_STDOUT:
 556                         pss->reason_bf |= 1;
 557                         /* when writing to MASTER would not block */
 558                         lws_callback_on_writable(wsi);
 559                         break;
 560                 case LWS_STDERR:
 561                         n = read(lws_get_socket_fd(pss->args.stdwsi[LWS_STDERR]),
 562                                         buf, 127);
 563                         //lwsl_notice("stderr reads %d\n", n);
 564                         if (n > 0) {
 565                                 if (buf[n - 1] != '\n')
 566                                         buf[n++] = '\n';
 567                                 buf[n] = '\0';
 568                                 lwsl_notice("CGI-stderr: %s\n", buf);
 569                         }
 570                         break;
 571                 }
 572                 break;
 573
 574         case LWS_CALLBACK_CGI_TERMINATED:
 575                 //lwsl_notice("LWS_CALLBACK_CGI_TERMINATED\n");
 576                 /* because we sent on openended http, close the connection */
 577                 return -1;
 578
 579         case LWS_CALLBACK_CGI_STDIN_DATA:  /* POST body for stdin */
 580                 //lwsl_notice("LWS_CALLBACK_CGI_STDIN_DATA\n");
 581                 pss->args = *((struct lws_cgi_args *)in);
 582                 n = write(lws_get_socket_fd(pss->args.stdwsi[LWS_STDIN]),
 583                           pss->args.data, pss->args.len);
 584                 //lwsl_notice("LWS_CALLBACK_CGI_STDIN_DATA: write says %d", n);
 585                 if (n < pss->args.len)
 586                         lwsl_notice("LWS_CALLBACK_CGI_STDIN_DATA: sent %d only %d went",
 587                                         n, pss->args.len);
 588                 return n;
 589 #endif
 590
 591         /*
 592          * callbacks for managing the external poll() array appear in
 593          * protocol 0 callback
 594          */
 595
 596         case LWS_CALLBACK_LOCK_POLL:
 597                 /*
 598                  * lock mutex to protect pollfd state
 599                  * called before any other POLL related callback
 600                  * if protecting wsi lifecycle change, len == 1
 601                  */
 602                 test_server_lock(len);
 603                 break;
 604
 605         case LWS_CALLBACK_UNLOCK_POLL:
 606                 /*
 607                  * unlock mutex to protect pollfd state when
 608                  * called after any other POLL related callback
 609                  * if protecting wsi lifecycle change, len == 1
 610                  */
 611                 test_server_unlock(len);
 612                 break;
 613
 614 #ifdef EXTERNAL_POLL
 615         case LWS_CALLBACK_ADD_POLL_FD:
 616
 617                 if (count_pollfds >= max_poll_elements) {
 618                         lwsl_err("LWS_CALLBACK_ADD_POLL_FD: too many sockets to track\n");
 619                         return 1;
 620                 }
 621
 622                 fd_lookup[pa->fd] = count_pollfds;
 623                 pollfds[count_pollfds].fd = pa->fd;
 624                 pollfds[count_pollfds].events = pa->events;
 625                 pollfds[count_pollfds++].revents = 0;
 626                 break;
 627
 628         case LWS_CALLBACK_DEL_POLL_FD:
 629                 if (!--count_pollfds)
 630                         break;
 631                 m = fd_lookup[pa->fd];
 632                 /* have the last guy take up the vacant slot */
 633                 pollfds[m] = pollfds[count_pollfds];
 634                 fd_lookup[pollfds[count_pollfds].fd] = m;
 635                 break;
 636
 637         case LWS_CALLBACK_CHANGE_MODE_POLL_FD:
 638                 pollfds[fd_lookup[pa->fd]].events = pa->events;
 639                 break;
 640 #endif
 641
 642         case LWS_CALLBACK_GET_THREAD_ID:
 643                 /*
 644                  * if you will call "lws_callback_on_writable"
 645                  * from a different thread, return the caller thread ID
 646                  * here so lws can use this information to work out if it
 647                  * should signal the poll() loop to exit and restart early
 648                  */
 649
 650                 /* return pthread_getthreadid_np(); */
 651
 652                 break;
 653
 654         default:
 655                 break;
 656         }
 657
 658         return 0;
 659
 660         /* if we're on HTTP1.1 or 2.0, will keep the idle connection alive */
 661 try_to_reuse:
 662         if (lws_http_transaction_completed(wsi))
 663                 return -1;
 664
 665         return 0;
 666 }