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nuttx-apps/system/telnet/telnet_client.c

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/****************************************************************************
* apps/system/telnet/telnet_client.c
*
* Leveraged from libtelnet, https://github.com/seanmiddleditch/libtelnet.
* Modified and re-released under the BSD license:
*
* Copyright (C) 2017 Gregory Nutt. All rights reserved.
* Author: Gregory Nutt <gnutt@nuttx.org>
*
* The original authors of libtelnet are listed below. Per their licesne,
* "The author or authors of this code dedicate any and all copyright
* interest in this code to the public domain. We make this dedication for
* the benefit of the public at large and to the detriment of our heirs and
* successors. We intend this dedication to be an overt act of
* relinquishment in perpetuity of all present and future rights to this
* code under copyright law."
*
* Author: Sean Middleditch <sean@sourcemud.org>
* (Also listed in the AUTHORS file are Jack Kelly <endgame.dos@gmail.com>
* and Katherine Flavel <kate@elide.org>)
*
* 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 NuttX 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 COPYRIGHT HOLDERS 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
* COPYRIGHT OWNER 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 <sys/types.h>
#include <sys/socket.h>
#include <unistd.h>
#include <poll.h>
#include <errno.h>
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <ctype.h>
#include <netdb.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#ifdef HAVE_ZLIB
# include "zlib.h"
#endif
#include "system/readline.h"
#include "netutils/telnetc.h"
/****************************************************************************
* Pre-processor Definitions
****************************************************************************/
#ifdef CONFIG_NSH_TELNETD_PORT
# define DEFAULT_PORT CONFIG_NSH_TELNETD_PORT
#else
# define DEFAULT_PORT 23
#endif
/****************************************************************************
* Private Data
****************************************************************************/
static struct telnet_s *g_telnet;
static int g_echo;
static const struct telnet_telopt_s g_telopts[] =
{
{
TELNET_TELOPT_ECHO, TELNET_WONT, TELNET_DO
},
{
TELNET_TELOPT_TTYPE, TELNET_WILL, TELNET_DONT
},
{
TELNET_TELOPT_COMPRESS2, TELNET_WONT, TELNET_DO
},
{
TELNET_TELOPT_MSSP, TELNET_WONT, TELNET_DO
},
{
-1, 0, 0
}
};
/****************************************************************************
* Private Functions
****************************************************************************/
static void send_local_input(char *buffer, int size)
{
static char crlf[] = { '\r', '\n' };
int i;
for (i = 0; i != size; ++i)
{
/* If we got a CR or LF, replace with CRLF NOTE that usually you'd get a
* CR in UNIX, but in raw mode we get LF instead (not sure why).
*/
if (buffer[i] == '\r' || buffer[i] == '\n')
{
if (g_echo)
{
printf("\r\n");
}
telnet_send(g_telnet, crlf, 2);
}
else
{
if (g_echo)
{
putchar(buffer[i]);
}
telnet_send(g_telnet, buffer + i, 1);
}
}
fflush(stdout);
}
static void telnet_ev_send(int sock, const char *buffer, size_t size)
{
int ret;
/* Send data */
while (size > 0)
{
if ((ret = send(sock, buffer, size, 0)) == -1)
{
fprintf(stderr, "send() failed: %d\n", errno);
exit(1);
}
else if (ret == 0)
{
fprintf(stderr, "send() unexpectedly returned 0\n");
exit(1);
}
/* Update pointer and size to see if we've got more to send */
buffer += ret;
size -= ret;
}
}
static void _event_handler(struct telnet_s *telnet,
union telnet_event_u *ev, void *user_data)
{
int sock = *(int *)user_data;
switch (ev->type)
{
/* Data received */
case TELNET_EV_DATA:
printf("%.*s", (int)ev->data.size, ev->data.buffer);
fflush(stdout);
break;
/* Data must be sent */
case TELNET_EV_SEND:
telnet_ev_send(sock, ev->data.buffer, ev->data.size);
break;
/* Request to enable remote feature (or receipt) */
case TELNET_EV_WILL:
/* We'll agree to turn off our echo if server wants us to stop */
if (ev->neg.telopt == TELNET_TELOPT_ECHO)
{
g_echo = 0;
}
break;
/* Notification of disabling remote feature (or receipt) */
case TELNET_EV_WONT:
if (ev->neg.telopt == TELNET_TELOPT_ECHO)
{
g_echo = 1;
}
break;
/* Request to enable local feature (or receipt) */
case TELNET_EV_DO:
break;
/* Demand to disable local feature (or receipt) */
case TELNET_EV_DONT:
break;
/* Respond to TTYPE commands */
case TELNET_EV_TTYPE:
/* Respond with our terminal type, if requested */
if (ev->ttype.cmd == TELNET_TTYPE_SEND)
{
telnet_ttype_is(telnet, getenv("TERM"));
}
break;
/* Respond to particular subnegotiations */
case TELNET_EV_SUBNEGOTIATION:
break;
/* Error */
case TELNET_EV_ERROR:
fprintf(stderr, "ERROR: %s\n", ev->error.msg);
exit(1);
default:
/* Ignore */
break;
}
}
static void show_usage(const char *progname, int exitcode)
{
fprintf(stderr, "Usage:\n");
fprintf(stderr, "\t%s <server-IP-addr> [<port>]\n", progname);
fprintf(stderr, "Where:\n");
fprintf(stderr, "\t<server-IP-addr> is the address of the Telnet server. Either\n");
fprintf(stderr, "\t\tIPv4 form: ddd.ddd.ddd.ddd\n");
fprintf(stderr, "\t\tIPv6 form: xxxx:xxxx:xxxx:xxxx:xxxx:xxxx:xxxx:xxxx\n");
fprintf(stderr, "\t<port> is the (optional) listening port of the Telnet server.\n");
fprintf(stderr, "\t\tDefault: %u\n", DEFAULT_PORT);
exit(exitcode) ;
}
/****************************************************************************
* Public Functions
****************************************************************************/
#ifdef BUILD_MODULE
int main(int argc, FAR char *argv[])
#else
int telnet_main(int argc, char *argv[])
#endif
{
char buffer[512];
union
{
struct sockaddr generic;
#ifdef CONFIG_NET_IPv6
struct sockaddr_in6 ipv6;
#endif
#ifdef CONFIG_NET_IPv4
struct sockaddr_in ipv4;
#endif
} server;
union
{
#ifdef CONFIG_NET_IPv6
struct sockaddr_in6 ipv6;
#endif
#ifdef CONFIG_NET_IPv4
struct sockaddr_in ipv4;
#endif
} local;
struct pollfd pfd[2];
sa_family_t family;
uint16_t addrlen;
int portno;
int sock;
int ret;
/* Check usage */
if (argc < 2 || argc > 3)
{
fprintf(stderr, "Invalid number of arguments\n");
show_usage(argv[0], 1);
}
/* Convert the port number to binary if provided */
if (argc == 3)
{
portno = atoi(argv[2]);
if (portno < 0 || portno > UINT16_MAX)
{
fprintf(stderr, "Invalid port number\n");
show_usage(argv[0], 1);
}
}
else
{
portno = DEFAULT_PORT;
}
/* Convert the <server-IP-addr> argument into a binary address */
memset(&local, 0, sizeof(local));
#ifdef CONFIG_NET_IPv6
addrlen = sizeof(struct sockaddr_in6);
family = AF_INET6;
local.ipv6.sin6_family = AF_INET6;
server.ipv6.sin6_family = AF_INET6;
server.ipv6.sin6_port = htons(portno);
ret = inet_pton(AF_INET6, argv[1], server.ipv6.sin6_addr.s6_addr);
if (ret < 0)
#endif
#ifdef CONFIG_NET_IPv4
{
addrlen = sizeof(struct sockaddr_in);
family = AF_INET;
local.ipv4.sin_family = AF_INET;
server.ipv4.sin_family = AF_INET;
server.ipv4.sin_port = htons(portno);
ret = inet_pton(AF_INET, argv[1], &server.ipv4.sin_addr);
}
if (ret < 0)
#endif
{
fprintf(stderr, "ERROR: <server-IP-addr> is invalid\n");
show_usage(argv[0], 1);
}
/* Create server socket */
sock = socket(family, SOCK_STREAM, 0);
if (sock < 0)
{
fprintf(stderr, "socket() failed: %d\n", errno);
return 1;
}
/* Bind server socket */
ret = bind(sock, (struct sockaddr *)&local, addrlen);
if (ret < 0)
{
fprintf(stderr, "bind() failed: %d\n", errno);
return 1;
}
/* Connect */
ret = connect(sock, &server.generic, addrlen);
if (ret < 0)
{
fprintf(stderr, "connect() failed: %d\n", errno);
return 1;
}
/* Set input echoing on by default */
g_echo = 1;
/* Initialize telnet box */
g_telnet = telnet_init(g_telopts, _event_handler, 0, &sock);
/* Initialize poll descriptors */
memset(pfd, 0, sizeof(pfd));
pfd[0].fd = 1;
pfd[0].events = POLLIN;
pfd[1].fd = sock;
pfd[1].events = POLLIN;
/* Loop while both connections are open */
while (poll(pfd, 2, -1) != -1)
{
/* Read from stdin */
if (pfd[0].revents & POLLIN)
{
ret = std_readline(buffer, sizeof(buffer));
if (ret > 0)
{
send_local_input(buffer, ret);
}
else if (ret == 0)
{
break;
}
else
{
fprintf(stderr, "recv(server) failed: %d\n", errno);
exit(1);
}
}
/* Read from client */
if (pfd[1].revents & POLLIN)
{
if ((ret = recv(sock, buffer, sizeof(buffer), 0)) > 0)
{
telnet_recv(g_telnet, buffer, ret);
}
else if (ret == 0)
{
break;
}
else
{
fprintf(stderr, "recv(client) failed: %d\n", errno);
exit(1);
}
}
}
/* Clean up */
telnet_free(g_telnet);
close(sock);
return 0;
}
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