/****************************************************************************
* netutils/telnetd/telnetd.c
*
* Copyright (C) 2007, 2009 Gregory Nutt. All rights reserved.
* Author: Gregory Nutt <spudmonkey@racsa.co.cr>
*
* This is a leverage of similar logic from uIP:
*
* Author: Adam Dunkels <adam@sics.se>
* Copyright (c) 2003, Adam Dunkels.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of the Institute nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
****************************************************************************/
/****************************************************************************
* Included Files
****************************************************************************/
#include <nuttx/config.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <stdint.h>
#include <stdio.h>
#include <unistd.h>
#include <stdlib.h>
#include <stdarg.h>
#include <string.h>
#include <pthread.h>
#include <debug.h>
#include <net/uip/telnetd.h>
#include <net/uip/uip-lib.h>
#include "shell.h"
/****************************************************************************
* Definitions
****************************************************************************/
#define ISO_nl 0x0a
#define ISO_cr 0x0d
#define STATE_NORMAL 0
#define STATE_IAC 1
#define STATE_WILL 2
#define STATE_WONT 3
#define STATE_DO 4
#define STATE_DONT 5
#define STATE_CLOSE 6
#define TELNET_IAC 255
#define TELNET_WILL 251
#define TELNET_WONT 252
#define TELNET_DO 253
#define TELNET_DONT 254
/* Configurable settings */
#ifndef CONFIG_NETUTILS_IOBUFFER_SIZE
# define CONFIG_NETUTILS_IOBUFFER_SIZE 512
#endif
#ifndef CONFIG_NETUTILS_CMD_SIZE
# define CONFIG_NETUTILS_CMD_SIZE 40
#endif
/* As threads are created to handle each request, a stack must be allocated
* for the thread. Use a default if the user provided no stacksize.
*/
#ifndef CONFIG_NETUTILS_TELNETDSTACKSIZE
# define CONFIG_NETUTILS_TELNETDSTACKSIZE 4096
#endif
/* Enabled dumping of all input/output buffers */
#undef CONFIG_NETUTILS_TELNETD_DUMPBUFFER
/****************************************************************************
* Private Types
****************************************************************************/
struct telnetd_s
{
int tn_sockfd;
char tn_iobuffer[CONFIG_NETUTILS_IOBUFFER_SIZE];
char tn_cmd[CONFIG_NETUTILS_CMD_SIZE];
uint8_t tn_bufndx;
uint8_t tn_state;
};
/****************************************************************************
* Private Functions
****************************************************************************/
/****************************************************************************
* Name: telnetd_dumpbuffer
*
* Description:
* Dump a buffer of data (debug only)
*
****************************************************************************/
#ifdef CONFIG_NETUTILS_TELNETD_DUMPBUFFER
static inline void telnetd_dumpbuffer(FAR const char *msg, FAR const char *buffer, unsigned int nbytes)
{
/* CONFIG_DEBUG, CONFIG_DEBUG_VERBOSE, and CONFIG_DEBUG_NET have to be
* defined or the following does nothing.
*/
nvdbgdumpbuffer(msg, (FAR const uint8_t*)buffer, nbytes);
}
#else
# define telnetd_dumpbuffer(msg,buffer,nbytes)
#endif
/****************************************************************************
* Name: telnetd_putchar
*
* Description:
* Add another parsed character to the TELNET command string
*
****************************************************************************/
static void telnetd_putchar(struct telnetd_s *pstate, uint8_t ch)
{
/* Ignore carriage returns */
if (ch == ISO_cr)
{
return;
}
/* Add all other characters to the cmd buffer */
pstate->tn_cmd[pstate->tn_bufndx] = ch;
/* If a newline was added or if the buffer is full, then process it now */
if (ch == ISO_nl || pstate->tn_bufndx == (CONFIG_NETUTILS_CMD_SIZE - 1))
{
if (pstate->tn_bufndx > 0)
{
pstate->tn_cmd[pstate->tn_bufndx] = '\0';
}
telnetd_dumpbuffer("TELNET CMD", pstate->tn_cmd, strlen(pstate->tn_cmd));
shell_input(pstate, pstate->tn_cmd);
pstate->tn_bufndx = 0;
}
else
{
pstate->tn_bufndx++;
vdbg("Add '%c', bufndx=%d\n", ch, pstate->tn_bufndx);
}
}
/****************************************************************************
* Name: telnetd_sendopt
*
* Description:
*
****************************************************************************/
static void telnetd_sendopt(struct telnetd_s *pstate, uint8_t option, uint8_t value)
{
uint8_t optbuf[4];
optbuf[0] = TELNET_IAC;
optbuf[1] = option;
optbuf[2] = value;
optbuf[3] = 0;
telnetd_dumpbuffer("Send optbuf", optbuf, 4);
if (send(pstate->tn_sockfd, optbuf, 4, 0) < 0)
{
dbg("[%d] Failed to send TELNET_IAC\n", pstate->tn_sockfd);
}
}
/****************************************************************************
* Name: telnetd_receive
*
* Description:
* Process a received TELENET buffer
*
****************************************************************************/
static int telnetd_receive(struct telnetd_s *pstate, size_t len)
{
char *ptr = pstate->tn_iobuffer;
uint8_t ch;
while (len > 0)
{
ch = *ptr++;
len--;
vdbg("ch=%02x state=%d\n", ch, pstate->tn_state);
switch (pstate->tn_state)
{
case STATE_IAC:
if (ch == TELNET_IAC)
{
telnetd_putchar(pstate, ch);
pstate->tn_state = STATE_NORMAL;
}
else
{
switch (ch)
{
case TELNET_WILL:
pstate->tn_state = STATE_WILL;
break;
case TELNET_WONT:
pstate->tn_state = STATE_WONT;
break;
case TELNET_DO:
pstate->tn_state = STATE_DO;
break;
case TELNET_DONT:
pstate->tn_state = STATE_DONT;
break;
default:
pstate->tn_state = STATE_NORMAL;
break;
}
}
break;
case STATE_WILL:
/* Reply with a DONT */
telnetd_sendopt(pstate, TELNET_DONT, ch);
pstate->tn_state = STATE_NORMAL;
break;
case STATE_WONT:
/* Reply with a DONT */
telnetd_sendopt(pstate, TELNET_DONT, ch);
pstate->tn_state = STATE_NORMAL;
break;
case STATE_DO:
/* Reply with a WONT */
telnetd_sendopt(pstate, TELNET_WONT, ch);
pstate->tn_state = STATE_NORMAL;
break;
case STATE_DONT:
/* Reply with a WONT */
telnetd_sendopt(pstate, TELNET_WONT, ch);
pstate->tn_state = STATE_NORMAL;
break;
case STATE_NORMAL:
if (ch == TELNET_IAC)
{
pstate->tn_state = STATE_IAC;
}
else
{
telnetd_putchar(pstate, ch);
}
break;
}
}
return OK;
}
/****************************************************************************
* Name: telnetd_handler
*
* Description:
* Each time a new connection to port 23 is made, a new thread is created
* that begins at this entry point. There should be exactly one argument
* and it should be the socket descriptor (+1).
*
****************************************************************************/
static void *telnetd_handler(void *arg)
{
struct telnetd_s *pstate = (struct telnetd_s *)malloc(sizeof(struct telnetd_s));
int sockfd = (int)arg;
int ret = ERROR;
dbg("[%d] Started\n", sockfd);
/* Verify that the state structure was successfully allocated */
if (pstate)
{
/* Initialize the thread state structure */
memset(pstate, 0, sizeof(struct telnetd_s));
pstate->tn_sockfd = sockfd;
pstate->tn_state = STATE_NORMAL;
/* Start up the shell */
shell_init(pstate);
shell_start(pstate);
/* Loop processing each TELNET command */
do
{
/* Read a buffer of data from the TELNET client */
ret = recv(pstate->tn_sockfd, pstate->tn_iobuffer, CONFIG_NETUTILS_IOBUFFER_SIZE, 0);
if (ret > 0)
{
/* Process the received TELNET data */
telnetd_dumpbuffer("Received buffer", pstate->tn_iobuffer, ret);
ret = telnetd_receive(pstate, ret);
}
}
while (ret >= 0 && pstate->tn_state != STATE_CLOSE);
dbg("[%d] ret=%d tn_state=%d\n", sockfd, ret, pstate->tn_state);
/* End of command processing -- Clean up and exit */
free(pstate);
}
/* Exit the task */
dbg("[%d] Exitting\n", sockfd);
close(sockfd);
return NULL;
}
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: telnetd_init
*
* Description:
* This is the main processing thread for telnetd. It never returns
* unless an error occurs
*
****************************************************************************/
void telnetd_init(void)
{
/* Execute telnetd_handler on each connection to port 23 */
uip_server(HTONS(23), telnetd_handler, CONFIG_NETUTILS_TELNETDSTACKSIZE);
}
/****************************************************************************
* Name: shell_prompt
*
* Description:
* Print a prompt to the shell window.
*
* This function can be used by the shell back-end to print out a prompt
* to the shell window.
*
****************************************************************************/
void shell_prompt(void *handle, char *str)
{
struct telnetd_s *pstate = (struct telnetd_s *)handle;
int len = strlen(str);
strncpy(pstate->tn_iobuffer, str, len);
telnetd_dumpbuffer("Shell prompt", pstate->tn_iobuffer, len);
if (send(pstate->tn_sockfd, pstate->tn_iobuffer, len, 0) < 0)
{
dbg("[%d] Failed to send prompt\n", pstate->tn_sockfd);
}
}
/****************************************************************************
* Name: shell_output
*
* Description:
* Print a string to the shell window.
*
* This function is implemented by the shell GUI / telnet server and
* can be called by the shell back-end to output a string in the
* shell window. The string is automatically appended with a linebreak.
*
****************************************************************************/
void shell_output(void *handle, const char *fmt, ...)
{
struct telnetd_s *pstate = (struct telnetd_s *)handle;
unsigned len;
va_list ap;
va_start(ap, fmt);
vsnprintf(pstate->tn_iobuffer, CONFIG_NETUTILS_IOBUFFER_SIZE, fmt, ap);
va_end(ap);
len = strlen(pstate->tn_iobuffer);
if (len < CONFIG_NETUTILS_IOBUFFER_SIZE - 2)
{
pstate->tn_iobuffer[len] = ISO_cr;
pstate->tn_iobuffer[len+1] = ISO_nl;
pstate->tn_iobuffer[len+2] = '\0';
}
telnetd_dumpbuffer("Shell output", pstate->tn_iobuffer, len+2);
if (send(pstate->tn_sockfd, pstate->tn_iobuffer, len+2, 0) < 0)
{
dbg("[%d] Failed to send response\n", pstate->tn_sockfd);
}
}
/****************************************************************************
* Name: shell_quit
*
* Description:
* Quit the shell
*
****************************************************************************/
void shell_quit(void *handle, char *str)
{
struct telnetd_s *pstate = (struct telnetd_s *)handle;
pstate->tn_state = STATE_CLOSE;
}