test-server/test-server-http.c

   1 /*
   2  * libwebsockets-test-server - libwebsockets test 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 #include "test-server.h"
  22
  23 /*
  24  * This demo server shows how to use libwebsockets for one or more
  25  * websocket protocols in the same server
  26  *
  27  * It defines the following websocket protocols:
  28  *
  29  *  dumb-increment-protocol:  once the socket is opened, an incrementing
  30  *                              ascii string is sent down it every 50ms.
  31  *                              If you send "reset\n" on the websocket, then
  32  *                              the incrementing number is reset to 0.
  33  *
  34  *  lws-mirror-protocol: copies any received packet to every connection also
  35  *                              using this protocol, including the sender
  36  */
  37
  38 enum demo_protocols {
  39         /* always first */
  40         PROTOCOL_HTTP = 0,
  41
  42         PROTOCOL_DUMB_INCREMENT,
  43         PROTOCOL_LWS_MIRROR,
  44
  45         /* always last */
  46         DEMO_PROTOCOL_COUNT
  47 };
  48
  49 /*
  50  * We take a strict whitelist approach to stop ../ attacks
  51  */
  52 struct serveable {
  53         const char *urlpath;
  54         const char *mimetype;
  55 };
  56
  57 /*
  58  * this is just an example of parsing handshake headers, you don't need this
  59  * in your code unless you will filter allowing connections by the header
  60  * content
  61  */
  62 void
  63 dump_handshake_info(struct libwebsocket *wsi)
  64 {
  65         int n = 0;
  66         char buf[256];
  67         const unsigned char *c;
  68
  69         do {
  70                 c = lws_token_to_string(n);
  71                 if (!c) {
  72                         n++;
  73                         continue;
  74                 }
  75
  76                 if (!lws_hdr_total_length(wsi, n)) {
  77                         n++;
  78                         continue;
  79                 }
  80
  81                 lws_hdr_copy(wsi, buf, sizeof buf, n);
  82
  83                 fprintf(stderr, "    %s = %s\n", (char *)c, buf);
  84                 n++;
  85         } while (c);
  86 }
  87
  88 const char * get_mimetype(const char *file)
  89 {
  90         int n = strlen(file);
  91
  92         if (n < 5)
  93                 return NULL;
  94
  95         if (!strcmp(&file[n - 4], ".ico"))
  96                 return "image/x-icon";
  97
  98         if (!strcmp(&file[n - 4], ".png"))
  99                 return "image/png";
 100
 101         if (!strcmp(&file[n - 5], ".html"))
 102                 return "text/html";
 103
 104         return NULL;
 105 }
 106
 107 /* this protocol server (always the first one) handles HTTP,
 108  *
 109  * Some misc callbacks that aren't associated with a protocol also turn up only
 110  * here on the first protocol server.
 111  */
 112
 113 int callback_http(struct libwebsocket_context *context,
 114                 struct libwebsocket *wsi,
 115                 enum libwebsocket_callback_reasons reason, void *user,
 116                                                            void *in, size_t len)
 117 {
 118         struct per_session_data__http *pss =
 119                         (struct per_session_data__http *)user;
 120         static unsigned char buffer[4096];
 121         struct stat stat_buf;
 122         char leaf_path[1024];
 123         const char *mimetype;
 124         char *other_headers;
 125         unsigned char *end;
 126         struct timeval tv;
 127         unsigned char *p;
 128         char buf[256];
 129         char b64[64];
 130         int n, m;
 131
 132 #ifdef EXTERNAL_POLL
 133         struct libwebsocket_pollargs *pa = (struct libwebsocket_pollargs *)in;
 134 #endif
 135
 136         switch (reason) {
 137         case LWS_CALLBACK_HTTP:
 138
 139                 dump_handshake_info(wsi);
 140
 141                 if (len < 1) {
 142                         lws_return_http_status(context, wsi,
 143                                                 HTTP_STATUS_BAD_REQUEST, NULL);
 144                         goto try_to_reuse;
 145                 }
 146
 147                 /* this example server has no concept of directories */
 148                 if (strchr((const char *)in + 1, '/')) {
 149                         lws_return_http_status(context, wsi,
 150                                                 HTTP_STATUS_FORBIDDEN, NULL);
 151                         goto try_to_reuse;
 152                 }
 153
 154                 /* if a legal POST URL, let it continue and accept data */
 155                 if (lws_hdr_total_length(wsi, WSI_TOKEN_POST_URI))
 156                         return 0;
 157
 158                 /* check for the "send a big file by hand" example case */
 159
 160                 if (!strcmp((const char *)in, "/leaf.jpg")) {
 161                         if (strlen(resource_path) > sizeof(leaf_path) - 10)
 162                                 return -1;
 163                         sprintf(leaf_path, "%s/leaf.jpg", resource_path);
 164
 165                         /* well, let's demonstrate how to send the hard way */
 166
 167                         p = buffer + LWS_SEND_BUFFER_PRE_PADDING;
 168                         end = p + sizeof(buffer) - LWS_SEND_BUFFER_PRE_PADDING;
 169 #ifdef _WIN32
 170                         pss->fd = open(leaf_path, O_RDONLY | _O_BINARY);
 171 #else
 172                         pss->fd = open(leaf_path, O_RDONLY);
 173 #endif
 174
 175                         if (pss->fd < 0)
 176                                 return -1;
 177
 178                         if (fstat(pss->fd, &stat_buf) < 0)
 179                                 return -1;
 180
 181                         /*
 182                          * we will send a big jpeg file, but it could be
 183                          * anything.  Set the Content-Type: appropriately
 184                          * so the browser knows what to do with it.
 185                          *
 186                          * Notice we use the APIs to build the header, which
 187                          * will do the right thing for HTTP 1/1.1 and HTTP2
 188                          * depending on what connection it happens to be working
 189                          * on
 190                          */
 191                         if (lws_add_http_header_status(context, wsi, 200, &p, end))
 192                                 return 1;
 193                         if (lws_add_http_header_by_token(context, wsi,
 194                                         WSI_TOKEN_HTTP_SERVER,
 195                                         (unsigned char *)"libwebsockets",
 196                                         13, &p, end))
 197                                 return 1;
 198                         if (lws_add_http_header_by_token(context, wsi,
 199                                         WSI_TOKEN_HTTP_CONTENT_TYPE,
 200                                         (unsigned char *)"image/jpeg",
 201                                         10, &p, end))
 202                                 return 1;
 203                         if (lws_add_http_header_content_length(context, wsi,
 204                                                 stat_buf.st_size, &p, end))
 205                                 return 1;
 206                         if (lws_finalize_http_header(context, wsi, &p, end))
 207                                 return 1;
 208
 209                         /*
 210                          * send the http headers...
 211                          * this won't block since it's the first payload sent
 212                          * on the connection since it was established
 213                          * (too small for partial)
 214                          *
 215                          * Notice they are sent using LWS_WRITE_HTTP_HEADERS
 216                          * which also means you can't send body too in one step,
 217                          * this is mandated by changes in HTTP2
 218                          */
 219
 220                         n = lws_write(wsi,
 221                                         buffer + LWS_SEND_BUFFER_PRE_PADDING,
 222                                         p - (buffer + LWS_SEND_BUFFER_PRE_PADDING),
 223                                         LWS_WRITE_HTTP_HEADERS);
 224
 225                         if (n < 0) {
 226                                 close(pss->fd);
 227                                 return -1;
 228                         }
 229                         /*
 230                          * book us a LWS_CALLBACK_HTTP_WRITEABLE callback
 231                          */
 232                         lws_callback_on_writable(context, wsi);
 233                         break;
 234                 }
 235
 236                 /* if not, send a file the easy way */
 237                 strcpy(buf, resource_path);
 238                 if (strcmp(in, "/")) {
 239                         if (*((const char *)in) != '/')
 240                                 strcat(buf, "/");
 241                         strncat(buf, in, sizeof(buf) - strlen(resource_path));
 242                 } else /* default file to serve */
 243                         strcat(buf, "/test.html");
 244                 buf[sizeof(buf) - 1] = '\0';
 245
 246                 /* refuse to serve files we don't understand */
 247                 mimetype = get_mimetype(buf);
 248                 if (!mimetype) {
 249                         lwsl_err("Unknown mimetype for %s\n", buf);
 250                         lws_return_http_status(context, wsi,
 251                                       HTTP_STATUS_UNSUPPORTED_MEDIA_TYPE, NULL);
 252                         return -1;
 253                 }
 254
 255                 /* demostrates how to set a cookie on / */
 256
 257                 other_headers = NULL;
 258                 n = 0;
 259                 if (!strcmp((const char *)in, "/") &&
 260                            !lws_hdr_total_length(wsi, WSI_TOKEN_HTTP_COOKIE)) {
 261                         /* this isn't very unguessable but it'll do for us */
 262                         gettimeofday(&tv, NULL);
 263                         n = sprintf(b64, "test=LWS_%u_%u_COOKIE;Max-Age=360000",
 264                                 (unsigned int)tv.tv_sec,
 265                                 (unsigned int)tv.tv_usec);
 266
 267                         p = (unsigned char *)leaf_path;
 268
 269                         if (lws_add_http_header_by_name(context, wsi,
 270                                 (unsigned char *)"set-cookie:",
 271                                 (unsigned char *)b64, n, &p,
 272                                 (unsigned char *)leaf_path + sizeof(leaf_path)))
 273                                 return 1;
 274                         n = (char *)p - leaf_path;
 275                         other_headers = leaf_path;
 276                 }
 277
 278                 n = lws_serve_http_file(context, wsi, buf,
 279                                                 mimetype, other_headers, n);
 280                 if (n < 0 || ((n > 0) && lws_http_transaction_completed(wsi)))
 281                         return -1; /* error or can't reuse connection: close the socket */
 282
 283                 /*
 284                  * notice that the sending of the file completes asynchronously,
 285                  * we'll get a LWS_CALLBACK_HTTP_FILE_COMPLETION callback when
 286                  * it's done
 287                  */
 288
 289                 break;
 290
 291         case LWS_CALLBACK_HTTP_BODY:
 292                 strncpy(buf, in, 20);
 293                 buf[20] = '\0';
 294                 if (len < 20)
 295                         buf[len] = '\0';
 296
 297                 lwsl_notice("LWS_CALLBACK_HTTP_BODY: %s... len %d\n",
 298                                 (const char *)buf, (int)len);
 299
 300                 break;
 301
 302         case LWS_CALLBACK_HTTP_BODY_COMPLETION:
 303                 lwsl_notice("LWS_CALLBACK_HTTP_BODY_COMPLETION\n");
 304                 /* the whole of the sent body arrived, close or reuse the connection */
 305                 lws_return_http_status(context, wsi,
 306                                                 HTTP_STATUS_OK, NULL);
 307                 goto try_to_reuse;
 308
 309         case LWS_CALLBACK_HTTP_FILE_COMPLETION:
 310                 goto try_to_reuse;
 311
 312         case LWS_CALLBACK_HTTP_WRITEABLE:
 313                 /*
 314                  * we can send more of whatever it is we were sending
 315                  */
 316                 do {
 317                         /* we'd like the send this much */
 318                         n = sizeof(buffer) - LWS_SEND_BUFFER_PRE_PADDING;
 319
 320                         /* but if the peer told us he wants less, we can adapt */
 321                         m = lws_get_peer_write_allowance(wsi);
 322
 323                         /* -1 means not using a protocol that has this info */
 324                         if (m == 0)
 325                                 /* right now, peer can't handle anything */
 326                                 goto later;
 327
 328                         if (m != -1 && m < n)
 329                                 /* he couldn't handle that much */
 330                                 n = m;
 331
 332                         n = read(pss->fd, buffer + LWS_SEND_BUFFER_PRE_PADDING,
 333                                                                         n);
 334                         /* problem reading, close conn */
 335                         if (n < 0)
 336                                 goto bail;
 337                         /* sent it all, close conn */
 338                         if (n == 0)
 339                                 goto flush_bail;
 340                         /*
 341                          * To support HTTP2, must take care about preamble space
 342                          *
 343                          * identification of when we send the last payload frame
 344                          * is handled by the library itself if you sent a
 345                          * content-length header
 346                          */
 347                         m = lws_write(wsi,
 348                                                buffer + LWS_SEND_BUFFER_PRE_PADDING,
 349                                                n, LWS_WRITE_HTTP);
 350                         if (m < 0)
 351                                 /* write failed, close conn */
 352                                 goto bail;
 353
 354                         /*
 355                          * http2 won't do this
 356                          */
 357                         if (m != n)
 358                                 /* partial write, adjust */
 359                                 if (lseek(pss->fd, m - n, SEEK_CUR) < 0)
 360                                         goto bail;
 361
 362                         if (m) /* while still active, extend timeout */
 363                                 lws_set_timeout(wsi,
 364                                         PENDING_TIMEOUT_HTTP_CONTENT, 5);
 365
 366                         /* if we have indigestion, let him clear it before eating more */
 367                         if (lws_partial_buffered(wsi))
 368                                 break;
 369
 370                 } while (!lws_send_pipe_choked(wsi));
 371
 372 later:
 373                 lws_callback_on_writable(context, wsi);
 374                 break;
 375 flush_bail:
 376                 /* true if still partial pending */
 377                 if (lws_partial_buffered(wsi)) {
 378                         lws_callback_on_writable(context, wsi);
 379                         break;
 380                 }
 381                 close(pss->fd);
 382                 goto try_to_reuse;
 383
 384 bail:
 385                 close(pss->fd);
 386                 return -1;
 387
 388         /*
 389          * callback for confirming to continue with client IP appear in
 390          * protocol 0 callback since no websocket protocol has been agreed
 391          * yet.  You can just ignore this if you won't filter on client IP
 392          * since the default uhandled callback return is 0 meaning let the
 393          * connection continue.
 394          */
 395         case LWS_CALLBACK_FILTER_NETWORK_CONNECTION:
 396
 397                 /* if we returned non-zero from here, we kill the connection */
 398                 break;
 399
 400         /*
 401          * callbacks for managing the external poll() array appear in
 402          * protocol 0 callback
 403          */
 404
 405         case LWS_CALLBACK_LOCK_POLL:
 406                 /*
 407                  * lock mutex to protect pollfd state
 408                  * called before any other POLL related callback
 409                  * if protecting wsi lifecycle change, len == 1
 410                  */
 411                 test_server_lock(len);
 412                 break;
 413
 414         case LWS_CALLBACK_UNLOCK_POLL:
 415                 /*
 416                  * unlock mutex to protect pollfd state when
 417                  * called after any other POLL related callback
 418                  * if protecting wsi lifecycle change, len == 1
 419                  */
 420                 test_server_unlock(len);
 421                 break;
 422
 423 #ifdef EXTERNAL_POLL
 424         case LWS_CALLBACK_ADD_POLL_FD:
 425
 426                 if (count_pollfds >= max_poll_elements) {
 427                         lwsl_err("LWS_CALLBACK_ADD_POLL_FD: too many sockets to track\n");
 428                         return 1;
 429                 }
 430
 431                 fd_lookup[pa->fd] = count_pollfds;
 432                 pollfds[count_pollfds].fd = pa->fd;
 433                 pollfds[count_pollfds].events = pa->events;
 434                 pollfds[count_pollfds++].revents = 0;
 435                 break;
 436
 437         case LWS_CALLBACK_DEL_POLL_FD:
 438                 if (!--count_pollfds)
 439                         break;
 440                 m = fd_lookup[pa->fd];
 441                 /* have the last guy take up the vacant slot */
 442                 pollfds[m] = pollfds[count_pollfds];
 443                 fd_lookup[pollfds[count_pollfds].fd] = m;
 444                 break;
 445
 446         case LWS_CALLBACK_CHANGE_MODE_POLL_FD:
 447                 pollfds[fd_lookup[pa->fd]].events = pa->events;
 448                 break;
 449 #endif
 450
 451         case LWS_CALLBACK_GET_THREAD_ID:
 452                 /*
 453                  * if you will call "lws_callback_on_writable"
 454                  * from a different thread, return the caller thread ID
 455                  * here so lws can use this information to work out if it
 456                  * should signal the poll() loop to exit and restart early
 457                  */
 458
 459                 /* return pthread_getthreadid_np(); */
 460
 461                 break;
 462
 463         default:
 464                 break;
 465         }
 466
 467         return 0;
 468
 469         /* if we're on HTTP1.1 or 2.0, will keep the idle connection alive */
 470 try_to_reuse:
 471         if (lws_http_transaction_completed(wsi))
 472                 return -1;
 473
 474         return 0;
 475 }