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nuttx-apps/system/telnet/telnet_chatd.c

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/****************************************************************************
* apps/system/telnet/telnet_chatd.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/socket.h>
#include <stdlib.h>
#include <unistd.h>
#include <stdio.h>
#include <string.h>
#include <ctype.h>
#include <poll.h>
#include <netdb.h>
#include <errno.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include "netutils/telnetc.h"
/****************************************************************************
* Pre-processor Definitions
****************************************************************************/
#define MAX_USERS 64
#define LINEBUFFER_SIZE 256
/****************************************************************************
* Private Types
****************************************************************************/
struct user_s
{
char *name;
int sock;
struct telnet_s *telnet;
char linebuf[256];
int linepos;
};
/****************************************************************************
* Private Data
****************************************************************************/
static const struct telnet_telopt_s g_telopts[] =
{
{
TELNET_TELOPT_COMPRESS2, TELNET_WILL, TELNET_DONT
},
{
-1, 0, 0
}
};
static struct user_s g_users[MAX_USERS];
/****************************************************************************
* Private Functions
****************************************************************************/
static void linebuffer_push(char *buffer, size_t size, int *linepos,
char ch, void (*cb) (const char *line, int overflow,
void *ud), void *ud)
{
/* CRLF -- line terminator */
if (ch == '\n' && *linepos > 0 && buffer[*linepos - 1] == '\r')
{
/* NUL terminate (replaces \r in buffer), notify app, clear */
buffer[*linepos - 1] = 0;
cb(buffer, 0, ud);
*linepos = 0;
/* CRNUL -- just a CR */
}
else if (ch == 0 && *linepos > 0 && buffer[*linepos - 1] == '\r')
{
/* So nothing, the CR is already in the buffer */
/* Anything else (including technically invalid CR followed by anything
* besides LF or NUL -- just buffer if we have room \r
*/
}
else if (*linepos != size)
{
buffer[(*linepos)++] = ch;
/* Buffer overflow */
}
else
{
/* Terminate (NOTE: eats a byte), notify app, clear buffer */
buffer[size - 1] = 0;
cb(buffer, size - 1, ud);
*linepos = 0;
}
}
static void _message(const char *from, const char *msg)
{
int i;
for (i = 0; i != MAX_USERS; ++i)
{
if (g_users[i].sock != -1)
{
telnet_printf(g_users[i].telnet, "%s: %s\n", from, msg);
}
}
}
static void _send(int sock, const char *buffer, unsigned int size)
{
int ret;
/* Ignore on invalid socket */
if (sock == -1)
{
return;
}
/* Send data */
while (size > 0)
{
if ((ret = send(sock, buffer, size, 0)) == -1)
{
if (errno != EINTR && errno != ECONNRESET)
{
fprintf(stderr, "send() failed: %d\n", errno);
exit(1);
}
else
{
return;
}
}
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;
}
}
/* Process input line */
static void _online(const char *line, int overflow, void *ud)
{
struct user_s *user = (struct user_s *)ud;
int i;
/* If the user has no name, this is his "login" */
if (user->name == 0)
{
/* Must not be empty, must be at least 32 chars */
if (strlen(line) == 0 || strlen(line) > 32)
{
telnet_printf(user->telnet, "Invalid name.\nEnter name: ");
return;
}
/* Must not already be in use */
for (i = 0; i != MAX_USERS; ++i)
{
if (g_users[i].name != 0 && strcmp(g_users[i].name, line) == 0)
{
telnet_printf(user->telnet, "Name in use.\nEnter name: ");
return;
}
}
/* Keep name */
user->name = strdup(line);
telnet_printf(user->telnet, "Welcome, %s!\n", line);
return;
}
/* If line is "quit" then, well, quit */
if (strcmp(line, "quit") == 0)
{
close(user->sock);
user->sock = -1;
_message(user->name, "** HAS QUIT **");
free(user->name);
user->name = 0;
return;
}
/* Just a message -- send to all users */
_message(user->name, line);
}
static void _input(struct user_s *user, const char *buffer, unsigned int size)
{
unsigned int i;
for (i = 0; i != size; ++i)
{
linebuffer_push(user->linebuf, sizeof(user->linebuf), &user->linepos,
(char)buffer[i], _online, user);
}
}
static void _event_handler(struct telnet_s *telnet,
union telnet_event_u *ev, void *user_data)
{
struct user_s *user = (struct user_s *)user_data;
switch (ev->type)
{
/* Data received */
case TELNET_EV_DATA:
_input(user, ev->data.buffer, ev->data.size);
telnet_negotiate(telnet, TELNET_WONT, TELNET_TELOPT_ECHO);
telnet_negotiate(telnet, TELNET_WILL, TELNET_TELOPT_ECHO);
break;
/* Data must be sent */
case TELNET_EV_SEND:
_send(user->sock, ev->data.buffer, ev->data.size);
break;
/* Enable compress2 if accepted by client */
case TELNET_EV_DO:
if (ev->neg.telopt == TELNET_TELOPT_COMPRESS2)
{
telnet_begin_compress2(telnet);
}
break;
/* Error */
case TELNET_EV_ERROR:
close(user->sock);
user->sock = -1;
if (user->name != 0)
{
_message(user->name, "** HAS HAD AN ERROR **");
free(user->name);
user->name = 0;
}
telnet_free(user->telnet);
break;
default:
/* Ignore */
break;
}
}
/****************************************************************************
* Public Functions
****************************************************************************/
#ifdef CONFIG_BUILD_KERNEL
int main(int argc, FAR char *argv[])
#else
int chatd_main(int argc, char *argv[])
#endif
{
char buffer[512];
short listen_port;
int listen_sock;
int ret;
int i;
struct sockaddr_in addr;
socklen_t addrlen;
struct pollfd pfd[MAX_USERS + 1];
/* Check usage */
if (argc != 2)
{
fprintf(stderr, "Usage:\n %s <port>\n", argv[0]);
return 1;
}
/* Initialize data structures */
memset(&pfd, 0, sizeof(pfd));
memset(g_users, 0, sizeof(g_users));
for (i = 0; i != MAX_USERS; ++i)
{
g_users[i].sock = -1;
}
/* Parse listening port */
listen_port = (short)strtol(argv[1], 0, 10);
/* Create listening socket */
if ((listen_sock = socket(AF_INET, SOCK_STREAM, 0)) == -1)
{
fprintf(stderr, "socket() failed: %d\n", errno);
return 1;
}
/* Reuse address option */
ret = 1;
setsockopt(listen_sock, SOL_SOCKET, SO_REUSEADDR, (void *)&ret, sizeof(ret));
/* Bind to listening addr/port */
memset(&addr, 0, sizeof(addr));
addr.sin_family = AF_INET;
addr.sin_addr.s_addr = INADDR_ANY;
addr.sin_port = htons(listen_port);
if (bind(listen_sock, (struct sockaddr *)&addr, sizeof(addr)) == -1)
{
fprintf(stderr, "bind() failed: %d\n", errno);
return 1;
}
/* Listen for clients */
if (listen(listen_sock, 5) == -1)
{
fprintf(stderr, "listen() failed: %d\n", errno);
return 1;
}
printf("LISTENING ON PORT %d\n", listen_port);
/* Initialize listening descriptors */
pfd[MAX_USERS].fd = listen_sock;
pfd[MAX_USERS].events = POLLIN;
/* Loop for ever */
for (;;)
{
/* Prepare for poll */
for (i = 0; i != MAX_USERS; ++i)
{
if (g_users[i].sock != -1)
{
pfd[i].fd = g_users[i].sock;
pfd[i].events = POLLIN;
}
else
{
pfd[i].fd = -1;
pfd[i].events = 0;
}
}
/* Poll */
ret = poll(pfd, MAX_USERS + 1, -1);
if (ret == -1 && errno != EINTR)
{
fprintf(stderr, "poll() failed: %d\n", errno);
return 1;
}
/* New connection */
if (pfd[MAX_USERS].revents & POLLIN)
{
/* Accept the sock */
addrlen = sizeof(addr);
if ((ret = accept(listen_sock, (struct sockaddr *)&addr,
&addrlen)) == -1)
{
fprintf(stderr, "accept() failed: %d\n", errno);
return 1;
}
printf("Connection received.\n");
/* Find a free user */
for (i = 0; i != MAX_USERS; ++i)
{
if (g_users[i].sock == -1)
{
break;
}
}
if (i == MAX_USERS)
{
printf(" rejected (too many users)\n");
_send(ret, "Too many users.\r\n", 14);
close(ret);
}
/* Init, welcome */
g_users[i].sock = ret;
g_users[i].telnet = telnet_init(g_telopts, _event_handler, 0, &g_users[i]);
telnet_negotiate(g_users[i].telnet, TELNET_WILL,
TELNET_TELOPT_COMPRESS2);
telnet_printf(g_users[i].telnet, "Enter name: ");
telnet_negotiate(g_users[i].telnet, TELNET_WILL, TELNET_TELOPT_ECHO);
}
/* Read from client */
for (i = 0; i != MAX_USERS; ++i)
{
/* Skip users that aren't actually connected */
if (g_users[i].sock == -1)
{
continue;
}
if (pfd[i].revents & POLLIN)
{
if ((ret = recv(g_users[i].sock, buffer, sizeof(buffer), 0)) > 0)
{
telnet_recv(g_users[i].telnet, buffer, ret);
}
else if (ret == 0)
{
printf("Connection closed.\n");
close(g_users[i].sock);
if (g_users[i].name != 0)
{
_message(g_users[i].name, "** HAS DISCONNECTED **");
free(g_users[i].name);
g_users[i].name = 0;
}
telnet_free(g_users[i].telnet);
g_users[i].sock = -1;
break;
}
else if (errno != EINTR)
{
fprintf(stderr, "recv(client) failed: %d\n", errno);
exit(1);
}
}
}
}
/* Not that we can reach this, but GCC will cry if it's not here */
return 0;
}
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