plugins: add telnetd plugin

Signed-off-by: staylightblow8 <liudf0716@gmail.com>

CMakeLists.txt

@@ -81,14 +81,19 @@ set(src_xfrpc
 	tcpmux.c
 	tcp_redir.c
 	)
-	
+
+set(src_xfrpc_plugins
+	plugins/telnetd.c)
+
 set(libs
 	ssl
 	crypto
 	event
 	z
 	m
-	json-c)
+	json-c
+	crypt
+	pthread)
 	
 set(test_libs
 	event
@@ -100,7 +105,7 @@ if (STATIC_BUILD STREQUAL "ON")
   add_link_options(-static)
 endif (STATIC_BUILD)
 
-add_executable(xfrpc ${src_xfrpc})
+add_executable(xfrpc ${src_xfrpc} ${src_xfrpc_plugins})
 target_link_libraries(xfrpc ${libs} ${static_libs} ${asan_c_libs})
 
 install(TARGETS xfrpc

client.h

@@ -100,6 +100,11 @@ struct proxy_service {
 	// load balance
 	char	*group;
 	char	*group_key;
+
+	// plugin
+	char	*plugin;
+	char	*plugin_user;
+	char	*plugin_pwd;
 	
 	// private arguments
 	UT_hash_handle hh;

config.c

@@ -32,6 +32,10 @@
 #include <syslog.h>
 #include <sys/utsname.h>
 
+#include <unistd.h>
+#include <shadow.h>
+#include <crypt.h>
+
 #include "ini.h"
 #include "uthash.h"
 #include "config.h"
@@ -173,9 +177,9 @@ new_proxy_service(const char *name)
 
 	ps->proxy_type 			= NULL;
 	ps->use_encryption 		= 0;
-	ps->local_port			= -1;
-	ps->remote_port			= -1;
-	ps->remote_data_port	= -1;
+	ps->local_port			= 0;
+	ps->remote_port			= 0;
+	ps->remote_data_port	= 0;
 	ps->use_compression 	= 0;
 	ps->use_encryption		= 0;
 
@@ -186,6 +190,13 @@ new_proxy_service(const char *name)
 	ps->http_user			= NULL;
 	ps->http_pwd			= NULL;
 
+	ps->group				= NULL;
+	ps->group_key			= NULL;
+
+	ps->plugin				= NULL;
+	ps->plugin_user			= NULL;
+	ps->plugin_pwd			= NULL;
+
 	return ps;
 }
 
@@ -262,6 +273,79 @@ validate_proxy(struct proxy_service *ps)
 	return 1;
 }
 
+static int 
+add_user_and_set_password(const char *username, const char *password) 
+{
+    struct passwd *pwd_entry;
+    struct spwd *spwd_entry;
+    char *encrypted_password;
+    FILE *passwd_file;
+
+    // Check if the user already exists.
+    if ((pwd_entry = getpwnam(username)) != NULL || (spwd_entry = getspnam(username)) != NULL) {
+		debug(LOG_ERR, "Error: User '%s' already exists.\n", username);
+        return 0; // Return 0 to indicate failure.
+    }
+
+    // Generate an encrypted password.
+    encrypted_password = crypt(password, "$6$randomsalt$");
+
+    if (encrypted_password == NULL) {
+		debug(LOG_ERR, "Error: Failed to generate an encrypted password.");
+        return 0; // Return 0 to indicate failure.
+    }
+
+    // Create a new user entry in the passwd file.
+    passwd_file = fopen("/etc/passwd", "a");
+    if (passwd_file == NULL) {
+		debug(LOG_ERR, "Error: Failed to open /etc/passwd for writing.");
+        return 0; // Return 0 to indicate failure.
+    }
+
+    fprintf(passwd_file, "%s:x:1001:1001::/home/%s:/bin/bash\n", username, username);
+    fclose(passwd_file);
+
+    // Create the user's home directory.
+    char home_directory[256];
+    snprintf(home_directory, sizeof(home_directory), "/home/%s", username);
+
+    if (mkdir(home_directory, 0755) != 0) {
+        perror("Error: Failed to create the user's home directory.");
+        return 0; // Return 0 to indicate failure.
+    }
+
+    // Set the user's encrypted password in the shadow file.
+    passwd_file = fopen("/etc/shadow", "a");
+    if (passwd_file == NULL) {
+        perror("Error: Failed to open /etc/shadow for writing.");
+        return 0; // Return 0 to indicate failure.
+    }
+
+    fprintf(passwd_file, "%s:%s:::::::\n", username, encrypted_password);
+    fclose(passwd_file);
+
+	debug(LOG_INFO, "User '%s' added to the system with the specified password and home directory.\n", username);
+    return 1; // Return 1 to indicate success.
+}
+
+static void
+process_plugin_conf(struct proxy_service *ps) 
+{
+	if (!ps || !ps->plugin)
+		return;
+
+	if (strcmp(ps->plugin, "telnetd") == 0) {
+		if (ps->local_port == 0)
+			ps->local_port = 23;
+		if (ps->local_ip == NULL)
+			ps->local_ip = strdup("127.0.0.1");
+
+		if (ps->plugin_user !=NULL && ps->plugin_pwd != NULL) {
+			add_user_and_set_password (ps->plugin_user, ps->plugin_pwd);
+		}
+	}
+}
+
 static int 
 proxy_service_handler(void *user, const char *sect, const char *nm, const char *value)
 {
@@ -330,6 +414,12 @@ proxy_service_handler(void *user, const char *sect, const char *nm, const char *
 		ps->group = strdup(value);
 	} else if (MATCH_NAME("group_key")) {
 		ps->group_key = strdup(value);
+	} else if (MATCH_NAME("plugin")) {
+		ps->plugin = strdup(value);
+	} else if (MATCH_NAME("plugin_user")) {
+		ps->plugin_user = strdup(value);
+	} else if (MATCH_NAME("plugin_pwd")) {
+		ps->plugin_pwd = strdup(value);
 	} else {
 		debug(LOG_ERR, "unknown option %s in section %s", nm, section);
 		SAFE_FREE(section);
@@ -347,6 +437,8 @@ proxy_service_handler(void *user, const char *sect, const char *nm, const char *
 		// start a thread to listen on local_port, and forward data to remote_port
 		if (ps->local_port == 0)
 			ps->local_port = DEFAULT_MSTSC_PORT;
+	} else if (ps->proxy_type && strcmp(ps->proxy_type, "tcp") == 0) {
+		process_plugin_conf(ps);
 	}
 	
 	SAFE_FREE(section);

plugins/telnetd.c

@@ -0,0 +1,612 @@
+/*
+ * Simple telnet server
+ * Bjorn Wesen, Axis Communications AB (bjornw@axis.com)
+ *
+ * This file is distributed under the GNU Public License (GPL),
+ * please see the file LICENSE for further information.
+ *
+ * ---------------------------------------------------------------------------
+ * (C) Copyright 2000, Axis Communications AB, LUND, SWEDEN
+ ****************************************************************************
+ *
+ * The telnetd manpage says it all:
+ *
+ *   Telnetd operates by allocating a pseudo-terminal device (see pty(4))  for
+ *   a client, then creating a login process which has the slave side of the
+ *   pseudo-terminal as stdin, stdout, and stderr. Telnetd manipulates the
+ *   master side of the pseudo-terminal, implementing the telnet protocol and
+ *   passing characters between the remote client and the login process.
+ *
+ * Vladimir Oleynik <dzo@simtreas.ru> 2001
+ *     Set process group corrections, initial busybox port
+ *
+ * BusyBox is distributed under version 2 of the General Public License please
+ * see the file LICENSE for further information. Version 2 is the only version
+ * of this license which this version of BusyBox
+ * (or modified versions derived from this one) may be
+ * distributed under.
+ * https://busybox.net/downloads/busybox-0.60.5.tar.bz2
+ */
+
+#include <sys/time.h>
+#include <sys/socket.h>
+#include <sys/wait.h>
+#include <sys/ioctl.h>
+#include <string.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <errno.h>
+#include <netinet/in.h>
+#include <fcntl.h>
+#include <stdio.h>
+#include <signal.h>
+#include <termios.h>
+#include <arpa/telnet.h>
+#include <ctype.h>
+#include <sys/syslog.h>
+#include <pthread.h>
+
+#include "telnetd.h"
+#include "../debug.h"
+
+
+typedef struct sockaddr_in sockaddr_type;
+static const char *loginpath = "/bin/login";
+
+/* shell name and arguments */
+
+static const char *argv_init[] = {NULL, NULL};
+
+/* structure that describes a session */
+
+struct tsession
+{
+	struct tsession *next;
+	int sockfd, ptyfd;
+	int shell_pid;
+	/* two circular buffers */
+	char *buf1, *buf2;
+	int rdidx1, wridx1, size1;
+	int rdidx2, wridx2, size2;
+};
+
+/*
+
+   This is how the buffers are used. The arrows indicate the movement
+   of data.
+
+   +-------+     wridx1++     +------+     rdidx1++     +----------+
+   |       | <--------------  | buf1 | <--------------  |          |
+   |       |     size1--      +------+     size1++      |          |
+   |  pty  |                                            |  socket  |
+   |       |     rdidx2++     +------+     wridx2++     |          |
+   |       |  --------------> | buf2 |  --------------> |          |
+   +-------+     size2++      +------+     size2--      +----------+
+
+   Each session has got two buffers.
+
+*/
+
+static int maxfd;
+static struct tsession *sessions;
+
+/*
+
+   Remove all IAC's from the buffer pointed to by bf (recieved IACs are ignored
+   and must be removed so as to not be interpreted by the terminal).  Make an
+   uninterrupted string of characters fit for the terminal.  Do this by packing
+   all characters meant for the terminal sequentially towards the end of bf.
+
+   Return a pointer to the beginning of the characters meant for the terminal.
+   and make *num_totty the number of characters that should be sent to
+   the terminal.
+
+   Note - If an IAC (3 byte quantity) starts before (bf + len) but extends
+   past (bf + len) then that IAC will be left unprocessed and *processed will be
+   less than len.
+
+   FIXME - if we mean to send 0xFF to the terminal then it will be escaped,
+   what is the escape character?  We aren't handling that situation here.
+
+   CR-LF ->'s CR mapping is also done here, for convenience
+
+  */
+static char *
+remove_iacs(struct tsession *ts, int *pnum_totty)
+{
+	unsigned char *ptr0 = ts->buf1 + ts->wridx1;
+	unsigned char *ptr = ptr0;
+	unsigned char *totty = ptr;
+	unsigned char *end = ptr + MIN(BUFSIZE - ts->wridx1, ts->size1);
+	int processed;
+	int num_totty;
+
+	while (ptr < end)
+	{
+		if (*ptr != IAC)
+		{
+			int c = *ptr;
+			*totty++ = *ptr++;
+			/* We now map \r\n ==> \r for pragmatic reasons.
+			 * Many client implementations send \r\n when
+			 * the user hits the CarriageReturn key.
+			 */
+			if (c == '\r' && (*ptr == '\n' || *ptr == 0) && ptr < end)
+				ptr++;
+		}
+		else
+		{
+			/*
+			 * TELOPT_NAWS support!
+			 */
+			if ((ptr + 2) >= end)
+			{
+				/* only the beginning of the IAC is in the
+				buffer we were asked to process, we can't
+				process this char. */
+				break;
+			}
+
+			/*
+			 * IAC -> SB -> TELOPT_NAWS -> 4-byte -> IAC -> SE
+			 */
+			else if (ptr[1] == SB && ptr[2] == TELOPT_NAWS)
+			{
+				struct winsize ws;
+				if ((ptr + 8) >= end)
+					break; /* incomplete, can't process */
+				ws.ws_col = (ptr[3] << 8) | ptr[4];
+				ws.ws_row = (ptr[5] << 8) | ptr[6];
+				(void)ioctl(ts->ptyfd, TIOCSWINSZ, (char *)&ws);
+				ptr += 9;
+			}
+			else
+			{
+				/* skip 3-byte IAC non-SB cmd */
+				ptr += 3;
+			}
+		}
+	}
+
+	processed = ptr - ptr0;
+	num_totty = totty - ptr0;
+	/* the difference between processed and num_to tty
+	   is all the iacs we removed from the stream.
+	   Adjust buf1 accordingly. */
+	ts->wridx1 += processed - num_totty;
+	ts->size1 -= processed - num_totty;
+	*pnum_totty = num_totty;
+	/* move the chars meant for the terminal towards the end of the
+	buffer. */
+	return memmove(ptr - num_totty, ptr0, num_totty);
+}
+
+static int 
+getpty(char *line)
+{
+#ifdef OLD_GETPTY
+	int p;
+	p = open("/dev/ptmx", 2);
+	if (p > 0)
+	{
+		grantpt(p);
+		unlockpt(p);
+		strcpy(line, ptsname(p));
+		return (p);
+	}
+	return -1;
+#else
+
+	int p;
+	p = open("/dev/ptmx", O_RDWR);
+	if (p >= 0)
+	{
+		grantpt(p);
+		unlockpt(p);
+		if (ptsname_r(p, line, GETPTY_BUFSIZE - 1) != 0)
+		{
+			debug(LOG_ERR, "ptsname error (is /dev/pts mounted?)");
+			return -1;
+		}
+		line[GETPTY_BUFSIZE - 1] = '\0';
+		return p;
+	}
+	struct stat stb;
+	int i;
+	int j;
+
+	strcpy(line, "/dev/ptyXX");
+
+	for (i = 0; i < 16; i++)
+	{
+		line[8] = "pqrstuvwxyzabcde"[i];
+		line[9] = '0';
+		if (stat(line, &stb) < 0)
+		{
+			continue;
+		}
+		for (j = 0; j < 16; j++)
+		{
+			line[9] = j < 10 ? j + '0' : j - 10 + 'a';
+			p = open(line, O_RDWR | O_NOCTTY);
+			if (p >= 0)
+			{
+				line[5] = 't';
+				return p;
+			}
+		}
+	}
+#endif
+}
+
+static void 
+send_iac(struct tsession *ts, unsigned char command, int option)
+{
+	/* We rely on that there is space in the buffer for now.  */
+	char *b = ts->buf2 + ts->rdidx2;
+	*b++ = IAC;
+	*b++ = command;
+	*b++ = option;
+	ts->rdidx2 += 3;
+	ts->size2 += 3;
+}
+
+static struct tsession *
+make_new_session(int sockfd)
+{
+	struct termios termbuf;
+	int pty, pid;
+	char tty_name[32];
+	struct tsession *ts = malloc(sizeof(struct tsession) + BUFSIZE * 2);
+
+	ts->buf1 = (char *)(&ts[1]);
+	ts->buf2 = ts->buf1 + BUFSIZE;
+	ts->sockfd = sockfd;
+
+	ts->rdidx1 = ts->wridx1 = ts->size1 = 0;
+	ts->rdidx2 = ts->wridx2 = ts->size2 = 0;
+
+	/* Got a new connection, set up a tty and spawn a shell.  */
+
+	pty = getpty(tty_name);
+
+	if (pty < 0)
+	{
+		debug(LOG_ERR, "All network ports in use!");
+		return 0;
+	}
+
+	if (pty > maxfd)
+		maxfd = pty;
+
+	ts->ptyfd = pty;
+
+	/* Make the telnet client understand we will echo characters so it
+	 * should not do it locally. We don't tell the client to run linemode,
+	 * because we want to handle line editing and tab completion and other
+	 * stuff that requires char-by-char support.
+	 */
+
+	send_iac(ts, DO, TELOPT_ECHO);
+	send_iac(ts, DO, TELOPT_NAWS);
+	send_iac(ts, DO, TELOPT_LFLOW);
+	send_iac(ts, WILL, TELOPT_ECHO);
+	send_iac(ts, WILL, TELOPT_SGA);
+
+	if ((pid = fork()) < 0)
+	{
+		syslog(LOG_ERR, "Can`t forking");
+	}
+	if (pid == 0)
+	{
+		/* In child, open the child's side of the tty.  */
+		int i;
+
+		for (i = 0; i <= maxfd; i++)
+			close(i);
+		/* make new process group */
+		setsid();
+
+		if (open(tty_name, O_RDWR) < 0)
+		{
+			syslog(LOG_ERR, "Could not open tty");
+			exit(1);
+		}
+		dup(0);
+		dup(0);
+
+		tcsetpgrp(0, getpid());
+
+		/* The pseudo-terminal allocated to the client is configured to operate in
+		 * cooked mode, and with XTABS CRMOD enabled (see tty(4)).
+		 */
+
+		tcgetattr(0, &termbuf);
+		termbuf.c_lflag |= ECHO; /* if we use readline we dont want this */
+		termbuf.c_oflag |= ONLCR | XTABS;
+		termbuf.c_iflag |= ICRNL;
+		termbuf.c_iflag &= ~IXOFF;
+		/*termbuf.c_lflag &= ~ICANON;*/
+		tcsetattr(0, TCSANOW, &termbuf);
+
+		/* exec shell, with correct argv and env */
+		execv(loginpath, (char *const *)argv_init);
+
+		/* NOT REACHED */
+		syslog(LOG_ERR, "execv error");
+		exit(1);
+	}
+
+	ts->shell_pid = pid;
+
+	return ts;
+}
+
+static void 
+free_session(struct tsession *ts)
+{
+	struct tsession *t = sessions;
+
+	/* Unlink this telnet session from the session list.  */
+	if (t == ts)
+		sessions = ts->next;
+	else
+	{
+		while (t->next != ts)
+			t = t->next;
+		t->next = ts->next;
+	}
+
+	kill(ts->shell_pid, SIGKILL);
+
+	wait4(ts->shell_pid, NULL, 0, NULL);
+
+	close(ts->ptyfd);
+	close(ts->sockfd);
+
+	if (ts->ptyfd == maxfd || ts->sockfd == maxfd)
+		maxfd--;
+	if (ts->ptyfd == maxfd || ts->sockfd == maxfd)
+		maxfd--;
+
+	free(ts);
+}
+
+// create a function for a thread, so we can use it in the main function
+static void *
+simple_telnetd_thread(void *arg)
+{
+	sockaddr_type sa;
+	int master_fd;
+	fd_set rdfdset, wrfdset;
+	int selret;
+	int on = 1;
+	uint16_t portnbr = arg ? *(uint16_t *)arg : 2323;
+	int maxlen, w, r;
+	free(arg);
+	debug(LOG_INFO, "Starting telnetd on port %d\n", portnbr);
+
+	if (access(loginpath, X_OK) < 0)
+	{
+		debug(LOG_ERR, "No login shell found at %s\n", loginpath);
+		return NULL;
+	}
+
+	argv_init[0] = loginpath;
+	sessions = 0;
+
+	/* Grab a TCP socket.  */
+	master_fd = socket(SOCKET_TYPE, SOCK_STREAM, 0);
+	if (master_fd < 0)
+	{
+		debug(LOG_ERR, "Unable to create socket\n");
+		return NULL;
+	}
+	(void)setsockopt(master_fd, SOL_SOCKET, SO_REUSEADDR, &on, sizeof(on));
+
+	/* Set it to listen to specified port.  */
+	memset((void *)&sa, 0, sizeof(sa));
+	sa.sin_family = AF_INET;
+	sa.sin_port = htons(portnbr);
+
+	if (bind(master_fd, (struct sockaddr *)&sa, sizeof(sa)) < 0)
+	{
+		debug(LOG_ERR, "Failed to bind socket: %s\n", strerror(errno));
+		close(master_fd);
+		return NULL;
+	}
+
+	if (listen(master_fd, 1) < 0)
+	{
+		debug(LOG_ERR, "Socket failed to listen\n");
+		close(master_fd);
+		return NULL;
+		
+	}
+
+	maxfd = master_fd;
+
+	do
+	{
+		struct tsession *ts;
+
+		FD_ZERO(&rdfdset);
+		FD_ZERO(&wrfdset);
+
+		/* select on the master socket, all telnet sockets and their
+		 * ptys if there is room in their respective session buffers.
+		 */
+
+		FD_SET(master_fd, &rdfdset);
+
+		ts = sessions;
+		while (ts)
+		{
+			/* buf1 is used from socket to pty
+			 * buf2 is used from pty to socket
+			 */
+			if (ts->size1 > 0)
+			{
+				FD_SET(ts->ptyfd, &wrfdset); /* can write to pty */
+			}
+			if (ts->size1 < BUFSIZE)
+			{
+				FD_SET(ts->sockfd, &rdfdset); /* can read from socket */
+			}
+			if (ts->size2 > 0)
+			{
+				FD_SET(ts->sockfd, &wrfdset); /* can write to socket */
+			}
+			if (ts->size2 < BUFSIZE)
+			{
+				FD_SET(ts->ptyfd, &rdfdset); /* can read from pty */
+			}
+			ts = ts->next;
+		}
+
+		selret = select(maxfd + 1, &rdfdset, &wrfdset, 0, 0);
+
+		if (!selret)
+			break;
+		/* First check for and accept new sessions.  */
+		if (FD_ISSET(master_fd, &rdfdset))
+		{
+			int fd, salen;
+
+			salen = sizeof(sa);
+			if ((fd = accept(master_fd, (struct sockaddr *)&sa,
+							 &salen)) < 0)
+			{
+				continue;
+			}
+			else
+			{
+				/* Create a new session and link it into
+					our active list.  */
+				struct tsession *new_ts = make_new_session(fd);
+				if (new_ts)
+				{
+					new_ts->next = sessions;
+					sessions = new_ts;
+					if (fd > maxfd)
+						maxfd = fd;
+				}
+				else
+				{
+					close(fd);
+				}
+			}
+		}
+
+		/* Then check for data tunneling.  */
+		ts = sessions;
+		while (ts)
+		{									  /* For all sessions...  */
+			struct tsession *next = ts->next; /* in case we free ts. */
+
+			if (ts->size1 && FD_ISSET(ts->ptyfd, &wrfdset))
+			{
+				int num_totty;
+				char *ptr;
+				/* Write to pty from buffer 1.  */
+
+				ptr = remove_iacs(ts, &num_totty);
+
+				w = write(ts->ptyfd, ptr, num_totty);
+				if (w < 0)
+				{
+					free_session(ts);
+					ts = next;
+					continue;
+				}
+				ts->wridx1 += w;
+				ts->size1 -= w;
+				if (ts->wridx1 == BUFSIZE)
+					ts->wridx1 = 0;
+			}
+
+			if (ts->size2 && FD_ISSET(ts->sockfd, &wrfdset))
+			{
+				/* Write to socket from buffer 2.  */
+				maxlen = MIN(BUFSIZE - ts->wridx2, ts->size2);
+				w = write(ts->sockfd, ts->buf2 + ts->wridx2, maxlen);
+				if (w < 0)
+				{
+					free_session(ts);
+					ts = next;
+					continue;
+				}
+				ts->wridx2 += w;
+				ts->size2 -= w;
+				if (ts->wridx2 == BUFSIZE)
+					ts->wridx2 = 0;
+			}
+
+			if (ts->size1 < BUFSIZE && FD_ISSET(ts->sockfd, &rdfdset))
+			{
+				/* Read from socket to buffer 1. */
+				maxlen = MIN(BUFSIZE - ts->rdidx1,
+							 BUFSIZE - ts->size1);
+				r = read(ts->sockfd, ts->buf1 + ts->rdidx1, maxlen);
+				if (!r || (r < 0 && errno != EINTR))
+				{
+					free_session(ts);
+					ts = next;
+					continue;
+				}
+				if (!*(ts->buf1 + ts->rdidx1 + r - 1))
+				{
+					r--;
+					if (!r)
+						continue;
+				}
+				ts->rdidx1 += r;
+				ts->size1 += r;
+				if (ts->rdidx1 == BUFSIZE)
+					ts->rdidx1 = 0;
+			}
+
+			if (ts->size2 < BUFSIZE && FD_ISSET(ts->ptyfd, &rdfdset))
+			{
+				/* Read from pty to buffer 2.  */
+				maxlen = MIN(BUFSIZE - ts->rdidx2,
+							 BUFSIZE - ts->size2);
+				r = read(ts->ptyfd, ts->buf2 + ts->rdidx2, maxlen);
+				if (!r || (r < 0 && errno != EINTR))
+				{
+					free_session(ts);
+					ts = next;
+					continue;
+				}
+				ts->rdidx2 += r;
+				ts->size2 += r;
+				if (ts->rdidx2 == BUFSIZE)
+					ts->rdidx2 = 0;
+			}
+
+			if (ts->size1 == 0)
+			{
+				ts->rdidx1 = 0;
+				ts->wridx1 = 0;
+			}
+			if (ts->size2 == 0)
+			{
+				ts->rdidx2 = 0;
+				ts->wridx2 = 0;
+			}
+			ts = next;
+		}
+	} while (1);
+
+	return 0;
+}
+
+int 
+simple_telnetd_start(uint16_t port)
+{
+	pthread_t thread;
+	uint16_t *port_ptr = malloc(sizeof(uint16_t));
+	*port_ptr = port;
+	pthread_create(&thread, NULL, simple_telnetd_thread, port_ptr);
+	return 0;
+}

plugins/telnetd.h

@@ -0,0 +1,14 @@
+#ifndef _TELNETD_H
+#define _TELNETD_H
+
+#define BUFSIZE 4000
+#define SOCKET_TYPE AF_INET
+#define MIN(X, Y) ((X) < (Y) ? (X) : (Y))
+enum
+{
+	GETPTY_BUFSIZE = 16
+};
+
+int  simple_telnetd_start(uint16_t port);
+
+#endif

xfrpc.c

@@ -48,6 +48,8 @@
 #include "tcp_redir.h"
 #include "config.h"
 
+#include "plugins/telnetd.h"
+
 static void start_xfrpc_local_service()
 {
 	// iterate all proxy service to find mstsc service
@@ -59,7 +61,12 @@ static void start_xfrpc_local_service()
 			// start tcp_redir for it
 			start_tcp_redir_service(ps);
 		}
+		if (ps->plugin && strcmp(ps->plugin, "telnetd") == 0) {
+			simple_telnetd_start(ps->local_port);
+		}
 	}
+
+	
 }
 
 void xfrpc_loop()