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   1 /***************************************************************************
   2  *   Copyright (C) 2005 by Dominic Rath                                    *
   3  *   Dominic.Rath@gmx.de                                                   *
   4  *                                                                         *
   5  *   Copyright (C) 2007,2008 Øyvind Harboe                                 *
   6  *   oyvind.harboe@zylin.com                                               *
   7  *                                                                         *
   8  *   Copyright (C) 2008 by Spencer Oliver                                  *
   9  *   spen@spen-soft.co.uk                                                  *
  10  *                                                                         *
  11  *   This program is free software; you can redistribute it and/or modify  *
  12  *   it under the terms of the GNU General Public License as published by  *
  13  *   the Free Software Foundation; either version 2 of the License, or     *
  14  *   (at your option) any later version.                                   *
  15  *                                                                         *
  16  *   This program is distributed in the hope that it will be useful,       *
  17  *   but WITHOUT ANY WARRANTY; without even the implied warranty of        *
  18  *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the         *
  19  *   GNU General Public License for more details.                          *
  20  *                                                                         *
  21  *   You should have received a copy of the GNU General Public License     *
  22  *   along with this program; if not, write to the                         *
  23  *   Free Software Foundation, Inc.,                                       *
  24  *   59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.             *
  25  ***************************************************************************/
  26 #ifdef HAVE_CONFIG_H
  27 #include "config.h"
  28 #endif
  29
  30 #include "telnet_server.h"
  31 #include <target/target_request.h>
  32
  33 static unsigned short telnet_port = 4444;
  34
  35 static char *negotiate =
  36                 "\xFF\xFB\x03"          /* IAC WILL Suppress Go Ahead */
  37                 "\xFF\xFB\x01"          /* IAC WILL Echo */
  38                 "\xFF\xFD\x03"          /* IAC DO Suppress Go Ahead */
  39                 "\xFF\xFE\x01";         /* IAC DON'T Echo */
  40
  41 #define CTRL(c) (c - '@')
  42
  43 /* The only way we can detect that the socket is closed is the first time
  44  * we write to it, we will fail. Subsequent write operations will
  45  * succeed. Shudder!
  46  */
  47 int telnet_write(struct connection *connection, const void *data, int len)
  48 {
  49         struct telnet_connection *t_con = connection->priv;
  50         if (t_con->closed)
  51                 return ERROR_SERVER_REMOTE_CLOSED;
  52
  53         if (write_socket(connection->fd, data, len) == len)
  54         {
  55                 return ERROR_OK;
  56         }
  57         t_con->closed = 1;
  58         return ERROR_SERVER_REMOTE_CLOSED;
  59 }
  60
  61 int telnet_prompt(struct connection *connection)
  62 {
  63         struct telnet_connection *t_con = connection->priv;
  64
  65         return telnet_write(connection, t_con->prompt, strlen(t_con->prompt));
  66 }
  67
  68 int telnet_outputline(struct connection *connection, const char *line)
  69 {
  70         int len;
  71
  72         /* process lines in buffer */
  73         while (*line) {
  74                 char *line_end = strchr(line, '\n');
  75
  76                 if (line_end)
  77                         len = line_end-line;
  78                 else
  79                         len = strlen(line);
  80
  81                 telnet_write(connection, line, len);
  82                 if (line_end)
  83                 {
  84                         telnet_write(connection, "\r\n", 2);
  85                         line += len + 1;
  86                 }
  87                 else
  88                 {
  89                         line += len;
  90                 }
  91         }
  92
  93         return ERROR_OK;
  94 }
  95
  96 int telnet_output(struct command_context *cmd_ctx, const char* line)
  97 {
  98         struct connection *connection = cmd_ctx->output_handler_priv;
  99
 100         return telnet_outputline(connection, line);
 101 }
 102
 103 void telnet_log_callback(void *priv, const char *file, unsigned line,
 104                 const char *function, const char *string)
 105 {
 106         struct connection *connection = priv;
 107         struct telnet_connection *t_con = connection->priv;
 108         int i;
 109
 110         /* if there is no prompt, simply output the message */
 111         if (t_con->line_cursor < 0)
 112         {
 113                 telnet_outputline(connection, string);
 114                 return;
 115         }
 116
 117         /* clear the command line */
 118         for (i = strlen(t_con->prompt) + t_con->line_size; i > 0; i -= 16)
 119                 telnet_write(connection, "\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b", i > 16 ? 16 : i);
 120         for (i = strlen(t_con->prompt) + t_con->line_size; i > 0; i -= 16)
 121                 telnet_write(connection, "                ", i > 16 ? 16 : i);
 122         for (i = strlen(t_con->prompt) + t_con->line_size; i > 0; i -= 16)
 123                 telnet_write(connection, "\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b\b", i > 16 ? 16 : i);
 124
 125         /* output the message */
 126         telnet_outputline(connection, string);
 127
 128         /* put the command line to its previous state */
 129         telnet_prompt(connection);
 130         telnet_write(connection, t_con->line, t_con->line_size);
 131         for (i = t_con->line_size; i > t_con->line_cursor; i--)
 132                 telnet_write(connection, "\b", 1);
 133 }
 134
 135 int telnet_new_connection(struct connection *connection)
 136 {
 137         struct telnet_connection *telnet_connection = malloc(sizeof(struct telnet_connection));
 138         struct telnet_service *telnet_service = connection->service->priv;
 139         int i;
 140
 141         connection->priv = telnet_connection;
 142
 143         /* initialize telnet connection information */
 144         telnet_connection->closed = 0;
 145         telnet_connection->line_size = 0;
 146         telnet_connection->line_cursor = 0;
 147         telnet_connection->option_size = 0;
 148         telnet_connection->prompt = strdup("> ");
 149         telnet_connection->state = TELNET_STATE_DATA;
 150
 151         /* output goes through telnet connection */
 152         command_set_output_handler(connection->cmd_ctx, telnet_output, connection);
 153
 154         /* negotiate telnet options */
 155         telnet_write(connection, negotiate, strlen(negotiate));
 156
 157         /* print connection banner */
 158         if (telnet_service->banner)
 159         {
 160                 telnet_write(connection, telnet_service->banner, strlen(telnet_service->banner));
 161                 telnet_write(connection, "\r\n", 2);
 162         }
 163
 164         telnet_write(connection, "\r", 1); /* the prompt is always placed at the line beginning */
 165         telnet_prompt(connection);
 166
 167         /* initialize history */
 168         for (i = 0; i < TELNET_LINE_HISTORY_SIZE; i++)
 169         {
 170                 telnet_connection->history[i] = NULL;
 171         }
 172         telnet_connection->next_history = 0;
 173         telnet_connection->current_history = 0;
 174
 175         log_add_callback(telnet_log_callback, connection);
 176
 177         return ERROR_OK;
 178 }
 179
 180 void telnet_clear_line(struct connection *connection, struct telnet_connection *t_con)
 181 {
 182         /* move to end of line */
 183         if (t_con->line_cursor < t_con->line_size)
 184         {
 185                 telnet_write(connection, t_con->line + t_con->line_cursor, t_con->line_size - t_con->line_cursor);
 186         }
 187
 188         /* backspace, overwrite with space, backspace */
 189         while (t_con->line_size > 0)
 190         {
 191                 telnet_write(connection, "\b \b", 3);
 192                 t_con->line_size--;
 193         }
 194         t_con->line_cursor = 0;
 195 }
 196
 197 int telnet_input(struct connection *connection)
 198 {
 199         int bytes_read;
 200         unsigned char buffer[TELNET_BUFFER_SIZE];
 201         unsigned char *buf_p;
 202         struct telnet_connection *t_con = connection->priv;
 203         struct command_context *command_context = connection->cmd_ctx;
 204
 205         bytes_read = read_socket(connection->fd, buffer, TELNET_BUFFER_SIZE);
 206
 207         if (bytes_read == 0)
 208                 return ERROR_SERVER_REMOTE_CLOSED;
 209         else if (bytes_read == -1)
 210         {
 211                 LOG_ERROR("error during read: %s", strerror(errno));
 212                 return ERROR_SERVER_REMOTE_CLOSED;
 213         }
 214
 215         buf_p = buffer;
 216         while (bytes_read)
 217         {
 218                 switch (t_con->state)
 219                 {
 220                         case TELNET_STATE_DATA:
 221                                 if (*buf_p == 0xff)
 222                                 {
 223                                         t_con->state = TELNET_STATE_IAC;
 224                                 }
 225                                 else
 226                                 {
 227                                         if (isprint(*buf_p)) /* printable character */
 228                                         {
 229                                                 /* watch buffer size leaving one spare character for string null termination */
 230                                                 if (t_con->line_size == TELNET_LINE_MAX_SIZE-1)
 231                                                 {
 232                                                         /* output audible bell if buffer is full */
 233                                                         telnet_write(connection, "\x07", 1); /* "\a" does not work, at least on windows */
 234                                                 }
 235                                                 else if (t_con->line_cursor == t_con->line_size)
 236                                                 {
 237                                                         telnet_write(connection, buf_p, 1);
 238                                                         t_con->line[t_con->line_size++] = *buf_p;
 239                                                         t_con->line_cursor++;
 240                                                 }
 241                                                 else
 242                                                 {
 243                                                         int i;
 244                                                         memmove(t_con->line + t_con->line_cursor + 1, t_con->line + t_con->line_cursor, t_con->line_size - t_con->line_cursor);
 245                                                         t_con->line[t_con->line_cursor] = *buf_p;
 246                                                         t_con->line_size++;
 247                                                         telnet_write(connection, t_con->line + t_con->line_cursor, t_con->line_size - t_con->line_cursor);
 248                                                         t_con->line_cursor++;
 249                                                         for (i = t_con->line_cursor; i < t_con->line_size; i++)
 250                                                         {
 251                                                                 telnet_write(connection, "\b", 1);
 252                                                         }
 253                                                 }
 254                                         }
 255                                         else /* non-printable */
 256                                         {
 257                                                 if (*buf_p == 0x1b) /* escape */
 258                                                 {
 259                                                         t_con->state = TELNET_STATE_ESCAPE;
 260                                                         t_con->last_escape = '\x00';
 261                                                 }
 262                                                 else if ((*buf_p == 0xd) || (*buf_p == 0xa)) /* CR/LF */
 263                                                 {
 264                                                         int retval;
 265
 266                                                         /* skip over combinations with CR/LF and NUL characters */
 267                                                         if ((bytes_read > 1) && ((*(buf_p + 1) == 0xa) || (*(buf_p + 1) == 0xd)))
 268                                                         {
 269                                                                 buf_p++;
 270                                                                 bytes_read--;
 271                                                         }
 272                                                         if ((bytes_read > 1) && (*(buf_p + 1) == 0))
 273                                                         {
 274                                                                 buf_p++;
 275                                                                 bytes_read--;
 276                                                         }
 277                                                         t_con->line[t_con->line_size] = 0;
 278
 279                                                         telnet_write(connection, "\r\n\x00", 3);
 280
 281                                                         if (strcmp(t_con->line, "history") == 0)
 282                                                         {
 283                                                                 int i;
 284                                                                 for (i = 1; i < TELNET_LINE_HISTORY_SIZE; i++)
 285                                                                 {
 286                                                                         /* the t_con->next_history line contains empty string (unless NULL), thus it is not printed */
 287                                                                         char *history_line = t_con->history[(t_con->next_history + i) % TELNET_LINE_HISTORY_SIZE];
 288                                                                         if (history_line)
 289                                                                         {
 290                                                                                 telnet_write(connection, history_line, strlen(history_line));
 291                                                                                 telnet_write(connection, "\r\n\x00", 3);
 292                                                                         }
 293                                                                 }
 294                                                                 t_con->line_size = 0;
 295                                                                 t_con->line_cursor = 0;
 296                                                                 continue;
 297                                                         }
 298
 299                                                         /* save only non-blank not repeating lines in the history */
 300                                                         char *prev_line = t_con->history[(t_con->current_history > 0) ? t_con->current_history - 1 : TELNET_LINE_HISTORY_SIZE-1];
 301                                                         if (*t_con->line && (prev_line == NULL || strcmp(t_con->line, prev_line)))
 302                                                         {
 303                                                                 /* if the history slot is already taken, free it */
 304                                                                 if (t_con->history[t_con->next_history])
 305                                                                 {
 306                                                                         free(t_con->history[t_con->next_history]);
 307                                                                 }
 308
 309                                                                 /* add line to history */
 310                                                                 t_con->history[t_con->next_history] = strdup(t_con->line);
 311
 312                                                                 /* wrap history at TELNET_LINE_HISTORY_SIZE */
 313                                                                 t_con->next_history = (t_con->next_history + 1) % TELNET_LINE_HISTORY_SIZE;
 314
 315                                                                 /* current history line starts at the new entry */
 316                                                                 t_con->current_history = t_con->next_history;
 317
 318                                                                 if (t_con->history[t_con->current_history])
 319                                                                 {
 320                                                                         free(t_con->history[t_con->current_history]);
 321                                                                 }
 322                                                                 t_con->history[t_con->current_history] = strdup("");
 323                                                         }
 324
 325                                                         t_con->line_size = 0;
 326
 327                                                         t_con->line_cursor = -1; /* to supress prompt in log callback during command execution */
 328
 329                                                         retval = command_run_line(command_context, t_con->line);
 330
 331                                                         t_con->line_cursor = 0;
 332
 333                                                         if (retval == ERROR_COMMAND_CLOSE_CONNECTION)
 334                                                                 return ERROR_SERVER_REMOTE_CLOSED;
 335
 336                                                         telnet_write(connection, "\r", 1); /* the prompt is always placed at the line beginning */
 337                                                         retval = telnet_prompt(connection);
 338                                                         if (retval == ERROR_SERVER_REMOTE_CLOSED)
 339                                                                 return ERROR_SERVER_REMOTE_CLOSED;
 340
 341                                                 }
 342                                                 else if ((*buf_p == 0x7f) || (*buf_p == 0x8)) /* delete character */
 343                                                 {
 344                                                         if (t_con->line_cursor > 0)
 345                                                         {
 346                                                                 if (t_con->line_cursor != t_con->line_size)
 347                                                                 {
 348                                                                         int i;
 349                                                                         telnet_write(connection, "\b", 1);
 350                                                                         t_con->line_cursor--;
 351                                                                         t_con->line_size--;
 352                                                                         memmove(t_con->line + t_con->line_cursor, t_con->line + t_con->line_cursor + 1, t_con->line_size - t_con->line_cursor);
 353
 354                                                                         telnet_write(connection, t_con->line + t_con->line_cursor, t_con->line_size - t_con->line_cursor);
 355                                                                         telnet_write(connection, " \b", 2);
 356                                                                         for (i = t_con->line_cursor; i < t_con->line_size; i++)
 357                                                                         {
 358                                                                                 telnet_write(connection, "\b", 1);
 359                                                                         }
 360                                                                 }
 361                                                                 else
 362                                                                 {
 363                                                                         t_con->line_size--;
 364                                                                         t_con->line_cursor--;
 365                                                                         /* back space: move the 'printer' head one char back, overwrite with space, move back again */
 366                                                                         telnet_write(connection, "\b \b", 3);
 367                                                                 }
 368                                                         }
 369                                                 }
 370                                                 else if (*buf_p == 0x15) /* clear line */
 371                                                 {
 372                                                         telnet_clear_line(connection, t_con);
 373                                                 }
 374                                                 else if (*buf_p == CTRL('B')) /* cursor left */
 375                                                 {
 376                                                         if (t_con->line_cursor > 0)
 377                                                         {
 378                                                                 telnet_write(connection, "\b", 1);
 379                                                                 t_con->line_cursor--;
 380                                                         }
 381                                                         t_con->state = TELNET_STATE_DATA;
 382                                                 }
 383                                                 else if (*buf_p == CTRL('F')) /* cursor right */
 384                                                 {
 385                                                         if (t_con->line_cursor < t_con->line_size)
 386                                                         {
 387                                                                 telnet_write(connection, t_con->line + t_con->line_cursor++, 1);
 388                                                         }
 389                                                         t_con->state = TELNET_STATE_DATA;
 390                                                 }
 391                                                 else
 392                                                 {
 393                                                         LOG_DEBUG("unhandled nonprintable: %2.2x", *buf_p);
 394                                                 }
 395                                         }
 396                                 }
 397                                 break;
 398                         case TELNET_STATE_IAC:
 399                                 switch (*buf_p)
 400                                 {
 401                                         case 0xfe:
 402                                                 t_con->state = TELNET_STATE_DONT;
 403                                                 break;
 404                                         case 0xfd:
 405                                                 t_con->state = TELNET_STATE_DO;
 406                                                 break;
 407                                         case 0xfc:
 408                                                 t_con->state = TELNET_STATE_WONT;
 409                                                 break;
 410                                         case 0xfb:
 411                                                 t_con->state = TELNET_STATE_WILL;
 412                                                 break;
 413                                 }
 414                                 break;
 415                         case TELNET_STATE_SB:
 416                                 break;
 417                         case TELNET_STATE_SE:
 418                                 break;
 419                         case TELNET_STATE_WILL:
 420                         case TELNET_STATE_WONT:
 421                         case TELNET_STATE_DO:
 422                         case TELNET_STATE_DONT:
 423                                 t_con->state = TELNET_STATE_DATA;
 424                                 break;
 425                         case TELNET_STATE_ESCAPE:
 426                                 if (t_con->last_escape == '[')
 427                                 {
 428                                         if (*buf_p == 'D') /* cursor left */
 429                                         {
 430                                                 if (t_con->line_cursor > 0)
 431                                                 {
 432                                                         telnet_write(connection, "\b", 1);
 433                                                         t_con->line_cursor--;
 434                                                 }
 435                                                 t_con->state = TELNET_STATE_DATA;
 436                                         }
 437                                         else if (*buf_p == 'C') /* cursor right */
 438                                         {
 439                                                 if (t_con->line_cursor < t_con->line_size)
 440                                                 {
 441                                                         telnet_write(connection, t_con->line + t_con->line_cursor++, 1);
 442                                                 }
 443                                                 t_con->state = TELNET_STATE_DATA;
 444                                         }
 445                                         else if (*buf_p == 'A') /* cursor up */
 446                                         {
 447                                                 int last_history = (t_con->current_history > 0) ? t_con->current_history - 1 : TELNET_LINE_HISTORY_SIZE-1;
 448                                                 if (t_con->history[last_history])
 449                                                 {
 450                                                         telnet_clear_line(connection, t_con);
 451                                                         t_con->line_size = strlen(t_con->history[last_history]);
 452                                                         t_con->line_cursor = t_con->line_size;
 453                                                         memcpy(t_con->line, t_con->history[last_history], t_con->line_size);
 454                                                         telnet_write(connection, t_con->line, t_con->line_size);
 455                                                         t_con->current_history = last_history;
 456                                                 }
 457                                                 t_con->state = TELNET_STATE_DATA;
 458                                         }
 459                                         else if (*buf_p == 'B') /* cursor down */
 460                                         {
 461                                                 int next_history = (t_con->current_history + 1) % TELNET_LINE_HISTORY_SIZE;
 462                                                 if (t_con->history[next_history])
 463                                                 {
 464                                                         telnet_clear_line(connection, t_con);
 465                                                         t_con->line_size = strlen(t_con->history[next_history]);
 466                                                         t_con->line_cursor = t_con->line_size;
 467                                                         memcpy(t_con->line, t_con->history[next_history], t_con->line_size);
 468                                                         telnet_write(connection, t_con->line, t_con->line_size);
 469                                                         t_con->current_history = next_history;
 470                                                 }
 471                                                 t_con->state = TELNET_STATE_DATA;
 472                                         }
 473                                         else if (*buf_p == '3')
 474                                         {
 475                                                 t_con->last_escape = *buf_p;
 476                                         }
 477                                         else
 478                                         {
 479                                                 t_con->state = TELNET_STATE_DATA;
 480                                         }
 481                                 }
 482                                 else if (t_con->last_escape == '3')
 483                                 {
 484                                         /* Remove character */
 485                                         if (*buf_p == '~')
 486                                         {
 487                                                 if (t_con->line_cursor < t_con->line_size)
 488                                                 {
 489                                                         int i;
 490                                                         t_con->line_size--;
 491                                                         /* remove char from line buffer */
 492                                                         memmove(t_con->line + t_con->line_cursor, t_con->line + t_con->line_cursor + 1, t_con->line_size - t_con->line_cursor);
 493
 494                                                         /* print remainder of buffer */
 495                                                         telnet_write(connection, t_con->line + t_con->line_cursor, t_con->line_size - t_con->line_cursor);
 496                                                         /* overwrite last char with whitespace */
 497                                                         telnet_write(connection, " \b", 2);
 498
 499                                                         /* move back to cursor position*/
 500                                                         for (i = t_con->line_cursor; i < t_con->line_size; i++)
 501                                                         {
 502                                                                 telnet_write(connection, "\b", 1);
 503                                                         }
 504                                                 }
 505
 506                                                 t_con->state = TELNET_STATE_DATA;
 507                                         }
 508                                         else
 509                                         {
 510                                                 t_con->state = TELNET_STATE_DATA;
 511                                         }
 512                                 }
 513                                 else if (t_con->last_escape == '\x00')
 514                                 {
 515                                         if (*buf_p == '[')
 516                                         {
 517                                                 t_con->last_escape = *buf_p;
 518                                         }
 519                                         else
 520                                         {
 521                                                 t_con->state = TELNET_STATE_DATA;
 522                                         }
 523                                 }
 524                                 else
 525                                 {
 526                                         LOG_ERROR("BUG: unexpected value in t_con->last_escape");
 527                                         t_con->state = TELNET_STATE_DATA;
 528                                 }
 529
 530                                 break;
 531                         default:
 532                                 LOG_ERROR("unknown telnet state");
 533                                 exit(-1);
 534                 }
 535
 536                 bytes_read--;
 537                 buf_p++;
 538         }
 539
 540         return ERROR_OK;
 541 }
 542
 543 int telnet_connection_closed(struct connection *connection)
 544 {
 545         struct telnet_connection *t_con = connection->priv;
 546         int i;
 547
 548         log_remove_callback(telnet_log_callback, connection);
 549
 550         if (t_con->prompt)
 551         {
 552                 free(t_con->prompt);
 553                 t_con->prompt = NULL;
 554         }
 555
 556         for (i = 0; i < TELNET_LINE_HISTORY_SIZE; i++)
 557         {
 558                 if (t_con->history[i])
 559                 {
 560                         free(t_con->history[i]);
 561                         t_con->history[i] = NULL;
 562                 }
 563         }
 564
 565         /* if this connection registered a debug-message receiver delete it */
 566         delete_debug_msg_receiver(connection->cmd_ctx, NULL);
 567
 568         if (connection->priv)
 569         {
 570                 free(connection->priv);
 571                 connection->priv = NULL;
 572         }
 573         else
 574         {
 575                 LOG_ERROR("BUG: connection->priv == NULL");
 576         }
 577
 578         return ERROR_OK;
 579 }
 580
 581 int telnet_set_prompt(struct connection *connection, char *prompt)
 582 {
 583         struct telnet_connection *t_con = connection->priv;
 584
 585         if (t_con->prompt != NULL)
 586                 free(t_con->prompt);
 587
 588         t_con->prompt = strdup(prompt);
 589
 590         return ERROR_OK;
 591 }
 592
 593 int telnet_init(char *banner)
 594 {
 595         struct telnet_service *telnet_service = malloc(sizeof(struct telnet_service));
 596
 597         if (telnet_port == 0)
 598         {
 599                 LOG_INFO("telnet port disabled");
 600                 free(telnet_service);
 601                 return ERROR_OK;
 602         }
 603
 604         telnet_service->banner = banner;
 605
 606         add_service("telnet", CONNECTION_TCP, telnet_port, 1, telnet_new_connection, telnet_input, telnet_connection_closed, telnet_service);
 607
 608         return ERROR_OK;
 609 }
 610
 611 /* daemon configuration command telnet_port */
 612 COMMAND_HANDLER(handle_telnet_port_command)
 613 {
 614         return CALL_COMMAND_HANDLER(server_port_command, &telnet_port);
 615 }
 616
 617 COMMAND_HANDLER(handle_exit_command)
 618 {
 619         return ERROR_COMMAND_CLOSE_CONNECTION;
 620 }
 621
 622 static const struct command_registration telnet_command_handlers[] = {
 623         {
 624                 .name = "exit",
 625                 .handler = handle_exit_command,
 626                 .mode = COMMAND_EXEC,
 627                 .help = "exit telnet session",
 628         },
 629         {
 630                 .name = "telnet_port",
 631                 .handler = handle_telnet_port_command,
 632                 .mode = COMMAND_ANY,
 633                 .help = "Specify port on which to listen "
 634                         "for incoming telnet connections.  "
 635                         "No arguments reports telnet port; zero disables.",
 636                 .usage = "[port_num]",
 637         },
 638         COMMAND_REGISTRATION_DONE
 639 };
 640
 641 int telnet_register_commands(struct command_context *cmd_ctx)
 642 {
 643         return register_commands(cmd_ctx, NULL, telnet_command_handlers);
 644 }