diff --git a/src/vty/vty.c b/src/vty/vty.c
new file mode 100644
index 0000000..66cc13b
--- /dev/null
+++ b/src/vty/vty.c
@@ -0,0 +1,1645 @@
+
+#include <stdio.h>
+#include <stdarg.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <string.h>
+#include <errno.h>
+#include <ctype.h>
+#include <termios.h>
+
+#include <sys/utsname.h>
+#include <sys/param.h>
+
+#include <arpa/telnet.h>
+
+#include "cardshell.h"
+#include <vty/vty.h>
+#include <vty/command.h>
+#include <vty/buffer.h>
+
+/* Vty events */
+enum event {
+	VTY_SERV,
+	VTY_READ,
+	VTY_WRITE,
+	VTY_TIMEOUT_RESET,
+#ifdef VTYSH
+	VTYSH_SERV,
+	VTYSH_READ,
+	VTYSH_WRITE
+#endif				/* VTYSH */
+};
+
+extern struct host host;
+
+/* Vector which store each vty structure. */
+static vector vtyvec;
+
+vector Vvty_serv_thread;
+
+char *vty_cwd = NULL;
+
+/* Configure lock. */
+static int vty_config;
+
+static int no_password_check = 1;
+
+static void vty_clear_buf(struct vty *vty)
+{
+	memset(vty->buf, 0, vty->max);
+}
+
+/* Allocate new vty struct. */
+struct vty *vty_new()
+{
+	struct vty *new = malloc(sizeof(struct vty));
+
+	if (!new)
+		goto out;
+
+	new->obuf = buffer_new(0);	/* Use default buffer size. */
+	if (!new->obuf)
+		goto out_new;
+	new->buf = calloc(1, VTY_BUFSIZ);
+	if (!new->buf)
+		goto out_obuf;
+
+	new->max = VTY_BUFSIZ;
+
+	return new;
+
+out_obuf:
+	free(new->obuf);
+out_new:
+	free(new);
+	new = NULL;
+out:
+	return new;
+}
+
+/* Authentication of vty */
+static void vty_auth(struct vty *vty, char *buf)
+{
+	char *passwd = NULL;
+	enum node_type next_node = 0;
+	int fail;
+	char *crypt(const char *, const char *);
+
+	switch (vty->node) {
+	case AUTH_NODE:
+		if (host.encrypt)
+			passwd = host.password_encrypt;
+		else
+			passwd = host.password;
+		if (host.advanced)
+			next_node = host.enable ? VIEW_NODE : ENABLE_NODE;
+		else
+			next_node = VIEW_NODE;
+		break;
+	case AUTH_ENABLE_NODE:
+		if (host.encrypt)
+			passwd = host.enable_encrypt;
+		else
+			passwd = host.enable;
+		next_node = ENABLE_NODE;
+		break;
+	}
+
+	if (passwd) {
+		if (host.encrypt)
+			fail = strcmp(crypt(buf, passwd), passwd);
+		else
+			fail = strcmp(buf, passwd);
+	} else
+		fail = 1;
+
+	if (!fail) {
+		vty->fail = 0;
+		vty->node = next_node;	/* Success ! */
+	} else {
+		vty->fail++;
+		if (vty->fail >= 3) {
+			if (vty->node == AUTH_NODE) {
+				vty_out(vty,
+					"%% Bad passwords, too many failures!%s",
+					VTY_NEWLINE);
+				vty->status = VTY_CLOSE;
+			} else {
+				/* AUTH_ENABLE_NODE */
+				vty->fail = 0;
+				vty_out(vty,
+					"%% Bad enable passwords, too many failures!%s",
+					VTY_NEWLINE);
+				vty->node = VIEW_NODE;
+			}
+		}
+	}
+}
+
+/* Close vty interface. */
+void vty_close(struct vty *vty)
+{
+	int i;
+
+	/* Flush buffer. */
+	buffer_flush_all(vty->obuf, vty->fd);
+
+	/* Free input buffer. */
+	buffer_free(vty->obuf);
+
+	/* Free command history. */
+	for (i = 0; i < VTY_MAXHIST; i++)
+		if (vty->hist[i])
+			free(vty->hist[i]);
+
+	/* Unset vector. */
+	vector_unset(vtyvec, vty->fd);
+
+	/* Close socket. */
+	if (vty->fd > 0)
+		close(vty->fd);
+
+	if (vty->buf)
+		free(vty->buf);
+
+	/* Check configure. */
+	vty_config_unlock(vty);
+
+	/* OK free vty. */
+	free(vty);
+}
+
+int vty_shell(struct vty *vty)
+{
+	return vty->type == VTY_SHELL ? 1 : 0;
+}
+
+
+/* VTY standard output function. */
+int vty_out(struct vty *vty, const char *format, ...)
+{
+	va_list args;
+	int len = 0;
+	int size = 1024;
+	char buf[1024];
+	char *p = NULL;
+
+	if (vty_shell(vty)) {
+		va_start(args, format);
+		vprintf(format, args);
+		va_end(args);
+	} else {
+		/* Try to write to initial buffer.  */
+		va_start(args, format);
+		len = vsnprintf(buf, sizeof buf, format, args);
+		va_end(args);
+
+		/* Initial buffer is not enough.  */
+		if (len < 0 || len >= size) {
+			while (1) {
+				if (len > -1)
+					size = len + 1;
+				else
+					size = size * 2;
+
+				p = realloc(p, size);
+				if (!p)
+					return -1;
+
+				va_start(args, format);
+				len = vsnprintf(p, size, format, args);
+				va_end(args);
+
+				if (len > -1 && len < size)
+					break;
+			}
+		}
+
+		/* When initial buffer is enough to store all output.  */
+		if (!p)
+			p = buf;
+
+		/* Pointer p must point out buffer. */
+		buffer_put(vty->obuf, (u_char *) p, len);
+
+		/* If p is not different with buf, it is allocated buffer.  */
+		if (p != buf)
+			free(p);
+	}
+
+	return len;
+}
+
+int vty_out_newline(struct vty *vty)
+{
+	char *p = vty_newline(vty);
+	buffer_put(vty->obuf, p, strlen(p));
+}
+
+int vty_config_lock(struct vty *vty)
+{
+	if (vty_config == 0) {
+		vty->config = 1;
+		vty_config = 1;
+	}
+	return vty->config;
+}
+
+int vty_config_unlock(struct vty *vty)
+{
+	if (vty_config == 1 && vty->config == 1) {
+		vty->config = 0;
+		vty_config = 0;
+	}
+	return vty->config;
+}
+
+static void vty_event(enum event event, int sock, struct vty *vty)
+{
+	fprintf(stdout, "vty_event(%d, %d, %p)\n", event, sock, vty);
+	buffer_flush_all(vty->obuf, sock);
+}
+
+/* Say hello to vty interface. */
+void vty_hello(struct vty *vty)
+{
+	if (host.motdfile) {
+		FILE *f;
+		char buf[4096];
+
+		f = fopen(host.motdfile, "r");
+		if (f) {
+			while (fgets(buf, sizeof(buf), f)) {
+				char *s;
+				/* work backwards to ignore trailling isspace() */
+				for (s = buf + strlen(buf);
+				     (s > buf) && isspace(*(s - 1)); s--) ;
+				*s = '\0';
+				vty_out(vty, "%s%s", buf, VTY_NEWLINE);
+			}
+			fclose(f);
+		} else
+			vty_out(vty, "MOTD file not found%s", VTY_NEWLINE);
+	} else if (host.motd)
+		vty_out(vty, host.motd);
+}
+
+/* Put out prompt and wait input from user. */
+static void vty_prompt(struct vty *vty)
+{
+	struct utsname names;
+	const char *hostname;
+
+	if (vty->type == VTY_TERM) {
+		hostname = host.name;
+		if (!hostname) {
+			uname(&names);
+			hostname = names.nodename;
+		}
+		vty_out(vty, cmd_prompt(vty->node), hostname);
+	}
+}
+
+/* Command execution over the vty interface. */
+static int vty_command(struct vty *vty, char *buf)
+{
+	int ret;
+	vector vline;
+
+	/* Split readline string up into the vector */
+	vline = cmd_make_strvec(buf);
+
+	if (vline == NULL)
+		return CMD_SUCCESS;
+
+	ret = cmd_execute_command(vline, vty, NULL, 0);
+	if (ret != CMD_SUCCESS)
+		switch (ret) {
+		case CMD_WARNING:
+			if (vty->type == VTY_FILE)
+				vty_out(vty, "Warning...%s", VTY_NEWLINE);
+			break;
+		case CMD_ERR_AMBIGUOUS:
+			vty_out(vty, "%% Ambiguous command.%s", VTY_NEWLINE);
+			break;
+		case CMD_ERR_NO_MATCH:
+			vty_out(vty, "%% Unknown command.%s", VTY_NEWLINE);
+			break;
+		case CMD_ERR_INCOMPLETE:
+			vty_out(vty, "%% Command incomplete.%s", VTY_NEWLINE);
+			break;
+		}
+	cmd_free_strvec(vline);
+
+	return ret;
+}
+
+static const char telnet_backward_char = 0x08;
+static const char telnet_space_char = ' ';
+
+/* Basic function to write buffer to vty. */
+static void vty_write(struct vty *vty, const char *buf, size_t nbytes)
+{
+	if ((vty->node == AUTH_NODE) || (vty->node == AUTH_ENABLE_NODE))
+		return;
+
+	/* Should we do buffering here ?  And make vty_flush (vty) ? */
+	buffer_put(vty->obuf, buf, nbytes);
+}
+
+/* Ensure length of input buffer.  Is buffer is short, double it. */
+static void vty_ensure(struct vty *vty, int length)
+{
+	if (vty->max <= length) {
+		vty->max *= 2;
+		vty->buf = realloc(vty->buf, vty->max);
+		// FIXME: check return
+	}
+}
+
+/* Basic function to insert character into vty. */
+static void vty_self_insert(struct vty *vty, char c)
+{
+	int i;
+	int length;
+
+	vty_ensure(vty, vty->length + 1);
+	length = vty->length - vty->cp;
+	memmove(&vty->buf[vty->cp + 1], &vty->buf[vty->cp], length);
+	vty->buf[vty->cp] = c;
+
+	vty_write(vty, &vty->buf[vty->cp], length + 1);
+	for (i = 0; i < length; i++)
+		vty_write(vty, &telnet_backward_char, 1);
+
+	vty->cp++;
+	vty->length++;
+}
+
+/* Self insert character 'c' in overwrite mode. */
+static void vty_self_insert_overwrite(struct vty *vty, char c)
+{
+	vty_ensure(vty, vty->length + 1);
+	vty->buf[vty->cp++] = c;
+
+	if (vty->cp > vty->length)
+		vty->length++;
+
+	if ((vty->node == AUTH_NODE) || (vty->node == AUTH_ENABLE_NODE))
+		return;
+
+	vty_write(vty, &c, 1);
+}
+
+/* Insert a word into vty interface with overwrite mode. */
+static void vty_insert_word_overwrite(struct vty *vty, char *str)
+{
+	int len = strlen(str);
+	vty_write(vty, str, len);
+	strcpy(&vty->buf[vty->cp], str);
+	vty->cp += len;
+	vty->length = vty->cp;
+}
+
+/* Forward character. */
+static void vty_forward_char(struct vty *vty)
+{
+	if (vty->cp < vty->length) {
+		vty_write(vty, &vty->buf[vty->cp], 1);
+		vty->cp++;
+	}
+}
+
+/* Backward character. */
+static void vty_backward_char(struct vty *vty)
+{
+	if (vty->cp > 0) {
+		vty->cp--;
+		vty_write(vty, &telnet_backward_char, 1);
+	}
+}
+
+/* Move to the beginning of the line. */
+static void vty_beginning_of_line(struct vty *vty)
+{
+	while (vty->cp)
+		vty_backward_char(vty);
+}
+
+/* Move to the end of the line. */
+static void vty_end_of_line(struct vty *vty)
+{
+	while (vty->cp < vty->length)
+		vty_forward_char(vty);
+}
+
+/* Add current command line to the history buffer. */
+static void vty_hist_add(struct vty *vty)
+{
+	int index;
+
+	if (vty->length == 0)
+		return;
+
+	index = vty->hindex ? vty->hindex - 1 : VTY_MAXHIST - 1;
+
+	/* Ignore the same string as previous one. */
+	if (vty->hist[index])
+		if (strcmp(vty->buf, vty->hist[index]) == 0) {
+			vty->hp = vty->hindex;
+			return;
+		}
+
+	/* Insert history entry. */
+	if (vty->hist[vty->hindex])
+		free(vty->hist[vty->hindex]);
+	vty->hist[vty->hindex] = strdup(vty->buf);
+
+	/* History index rotation. */
+	vty->hindex++;
+	if (vty->hindex == VTY_MAXHIST)
+		vty->hindex = 0;
+
+	vty->hp = vty->hindex;
+}
+
+/* Get telnet window size. */
+static int
+vty_telnet_option (struct vty *vty, unsigned char *buf, int nbytes)
+{
+#ifdef TELNET_OPTION_DEBUG
+  int i;
+
+  for (i = 0; i < nbytes; i++)
+    {
+      switch (buf[i])
+	{
+	case IAC:
+	  vty_out (vty, "IAC ");
+	  break;
+	case WILL:
+	  vty_out (vty, "WILL ");
+	  break;
+	case WONT:
+	  vty_out (vty, "WONT ");
+	  break;
+	case DO:
+	  vty_out (vty, "DO ");
+	  break;
+	case DONT:
+	  vty_out (vty, "DONT ");
+	  break;
+	case SB:
+	  vty_out (vty, "SB ");
+	  break;
+	case SE:
+	  vty_out (vty, "SE ");
+	  break;
+	case TELOPT_ECHO:
+	  vty_out (vty, "TELOPT_ECHO %s", VTY_NEWLINE);
+	  break;
+	case TELOPT_SGA:
+	  vty_out (vty, "TELOPT_SGA %s", VTY_NEWLINE);
+	  break;
+	case TELOPT_NAWS:
+	  vty_out (vty, "TELOPT_NAWS %s", VTY_NEWLINE);
+	  break;
+	default:
+	  vty_out (vty, "%x ", buf[i]);
+	  break;
+	}
+    }
+  vty_out (vty, "%s", VTY_NEWLINE);
+
+#endif /* TELNET_OPTION_DEBUG */
+
+  switch (buf[0])
+    {
+    case SB:
+      vty->sb_len = 0;
+      vty->iac_sb_in_progress = 1;
+      return 0;
+      break;
+    case SE: 
+      {
+	if (!vty->iac_sb_in_progress)
+	  return 0;
+
+	if ((vty->sb_len == 0) || (vty->sb_buf[0] == '\0'))
+	  {
+	    vty->iac_sb_in_progress = 0;
+	    return 0;
+	  }
+	switch (vty->sb_buf[0])
+	  {
+	  case TELOPT_NAWS:
+	    if (vty->sb_len != TELNET_NAWS_SB_LEN)
+	      vty_out(vty,"RFC 1073 violation detected: telnet NAWS option "
+			"should send %d characters, but we received %lu",
+			TELNET_NAWS_SB_LEN, (u_long)vty->sb_len);
+	    else if (sizeof(vty->sb_buf) < TELNET_NAWS_SB_LEN)
+	      vty_out(vty, "Bug detected: sizeof(vty->sb_buf) %lu < %d, "
+		       "too small to handle the telnet NAWS option",
+		       (u_long)sizeof(vty->sb_buf), TELNET_NAWS_SB_LEN);
+	    else
+	      {
+		vty->width = ((vty->sb_buf[1] << 8)|vty->sb_buf[2]);
+		vty->height = ((vty->sb_buf[3] << 8)|vty->sb_buf[4]);
+#ifdef TELNET_OPTION_DEBUG
+		vty_out(vty, "TELNET NAWS window size negotiation completed: "
+			      "width %d, height %d%s",
+			vty->width, vty->height, VTY_NEWLINE);
+#endif
+	      }
+	    break;
+	  }
+	vty->iac_sb_in_progress = 0;
+	return 0;
+	break;
+      }
+    default:
+      break;
+    }
+  return 1;
+}
+
+/* Execute current command line. */
+static int vty_execute(struct vty *vty)
+{
+	int ret;
+
+	ret = CMD_SUCCESS;
+
+	switch (vty->node) {
+	case AUTH_NODE:
+	case AUTH_ENABLE_NODE:
+		vty_auth(vty, vty->buf);
+		break;
+	default:
+		ret = vty_command(vty, vty->buf);
+		if (vty->type == VTY_TERM)
+			vty_hist_add(vty);
+		break;
+	}
+
+	/* Clear command line buffer. */
+	vty->cp = vty->length = 0;
+	vty_clear_buf(vty);
+
+	if (vty->status != VTY_CLOSE)
+		vty_prompt(vty);
+
+	return ret;
+}
+
+/* Send WILL TELOPT_ECHO to remote server. */
+static void
+vty_will_echo (struct vty *vty)
+{
+	unsigned char cmd[] = { IAC, WILL, TELOPT_ECHO, '\0' };
+	vty_out (vty, "%s", cmd);
+}
+
+/* Make suppress Go-Ahead telnet option. */
+static void
+vty_will_suppress_go_ahead (struct vty *vty)
+{
+	unsigned char cmd[] = { IAC, WILL, TELOPT_SGA, '\0' };
+	vty_out (vty, "%s", cmd);
+}
+
+/* Make don't use linemode over telnet. */
+static void
+vty_dont_linemode (struct vty *vty)
+{
+	unsigned char cmd[] = { IAC, DONT, TELOPT_LINEMODE, '\0' };
+	vty_out (vty, "%s", cmd);
+}
+
+/* Use window size. */
+static void
+vty_do_window_size (struct vty *vty)
+{
+	unsigned char cmd[] = { IAC, DO, TELOPT_NAWS, '\0' };
+	vty_out (vty, "%s", cmd);
+}
+
+static void vty_kill_line_from_beginning(struct vty *);
+static void vty_redraw_line(struct vty *);
+
+/* Print command line history.  This function is called from
+   vty_next_line and vty_previous_line. */
+static void vty_history_print(struct vty *vty)
+{
+	int length;
+
+	vty_kill_line_from_beginning(vty);
+
+	/* Get previous line from history buffer */
+	length = strlen(vty->hist[vty->hp]);
+	memcpy(vty->buf, vty->hist[vty->hp], length);
+	vty->cp = vty->length = length;
+
+	/* Redraw current line */
+	vty_redraw_line(vty);
+}
+
+/* Show next command line history. */
+static void vty_next_line(struct vty *vty)
+{
+	int try_index;
+
+	if (vty->hp == vty->hindex)
+		return;
+
+	/* Try is there history exist or not. */
+	try_index = vty->hp;
+	if (try_index == (VTY_MAXHIST - 1))
+		try_index = 0;
+	else
+		try_index++;
+
+	/* If there is not history return. */
+	if (vty->hist[try_index] == NULL)
+		return;
+	else
+		vty->hp = try_index;
+
+	vty_history_print(vty);
+}
+
+/* Show previous command line history. */
+static void vty_previous_line(struct vty *vty)
+{
+	int try_index;
+
+	try_index = vty->hp;
+	if (try_index == 0)
+		try_index = VTY_MAXHIST - 1;
+	else
+		try_index--;
+
+	if (vty->hist[try_index] == NULL)
+		return;
+	else
+		vty->hp = try_index;
+
+	vty_history_print(vty);
+}
+
+/* This function redraw all of the command line character. */
+static void vty_redraw_line(struct vty *vty)
+{
+	vty_write(vty, vty->buf, vty->length);
+	vty->cp = vty->length;
+}
+
+/* Forward word. */
+static void vty_forward_word(struct vty *vty)
+{
+	while (vty->cp != vty->length && vty->buf[vty->cp] != ' ')
+		vty_forward_char(vty);
+
+	while (vty->cp != vty->length && vty->buf[vty->cp] == ' ')
+		vty_forward_char(vty);
+}
+
+/* Backward word without skipping training space. */
+static void vty_backward_pure_word(struct vty *vty)
+{
+	while (vty->cp > 0 && vty->buf[vty->cp - 1] != ' ')
+		vty_backward_char(vty);
+}
+
+/* Backward word. */
+static void vty_backward_word(struct vty *vty)
+{
+	while (vty->cp > 0 && vty->buf[vty->cp - 1] == ' ')
+		vty_backward_char(vty);
+
+	while (vty->cp > 0 && vty->buf[vty->cp - 1] != ' ')
+		vty_backward_char(vty);
+}
+
+/* When '^D' is typed at the beginning of the line we move to the down
+   level. */
+static void vty_down_level(struct vty *vty)
+{
+	vty_out(vty, "%s", VTY_NEWLINE);
+	(*config_exit_cmd.func) (NULL, vty, 0, NULL);
+	vty_prompt(vty);
+	vty->cp = 0;
+}
+
+/* When '^Z' is received from vty, move down to the enable mode. */
+static void vty_end_config(struct vty *vty)
+{
+	vty_out(vty, "%s", VTY_NEWLINE);
+
+	switch (vty->node) {
+	case VIEW_NODE:
+	case ENABLE_NODE:
+		/* Nothing to do. */
+		break;
+	case CONFIG_NODE:
+	case INTERFACE_NODE:
+	case ZEBRA_NODE:
+	case RIP_NODE:
+	case RIPNG_NODE:
+	case BGP_NODE:
+	case BGP_VPNV4_NODE:
+	case BGP_IPV4_NODE:
+	case BGP_IPV4M_NODE:
+	case BGP_IPV6_NODE:
+	case RMAP_NODE:
+	case OSPF_NODE:
+	case OSPF6_NODE:
+	case ISIS_NODE:
+	case KEYCHAIN_NODE:
+	case KEYCHAIN_KEY_NODE:
+	case MASC_NODE:
+	case VTY_NODE:
+		vty_config_unlock(vty);
+		vty->node = ENABLE_NODE;
+		break;
+	default:
+		/* Unknown node, we have to ignore it. */
+		break;
+	}
+
+	vty_prompt(vty);
+	vty->cp = 0;
+}
+
+/* Delete a charcter at the current point. */
+static void vty_delete_char(struct vty *vty)
+{
+	int i;
+	int size;
+
+	if (vty->node == AUTH_NODE || vty->node == AUTH_ENABLE_NODE)
+		return;
+
+	if (vty->length == 0) {
+		vty_down_level(vty);
+		return;
+	}
+
+	if (vty->cp == vty->length)
+		return;		/* completion need here? */
+
+	size = vty->length - vty->cp;
+
+	vty->length--;
+	memmove(&vty->buf[vty->cp], &vty->buf[vty->cp + 1], size - 1);
+	vty->buf[vty->length] = '\0';
+
+	vty_write(vty, &vty->buf[vty->cp], size - 1);
+	vty_write(vty, &telnet_space_char, 1);
+
+	for (i = 0; i < size; i++)
+		vty_write(vty, &telnet_backward_char, 1);
+}
+
+/* Delete a character before the point. */
+static void vty_delete_backward_char(struct vty *vty)
+{
+	if (vty->cp == 0)
+		return;
+
+	vty_backward_char(vty);
+	vty_delete_char(vty);
+}
+
+/* Kill rest of line from current point. */
+static void vty_kill_line(struct vty *vty)
+{
+	int i;
+	int size;
+
+	size = vty->length - vty->cp;
+
+	if (size == 0)
+		return;
+
+	for (i = 0; i < size; i++)
+		vty_write(vty, &telnet_space_char, 1);
+	for (i = 0; i < size; i++)
+		vty_write(vty, &telnet_backward_char, 1);
+
+	memset(&vty->buf[vty->cp], 0, size);
+	vty->length = vty->cp;
+}
+
+/* Kill line from the beginning. */
+static void vty_kill_line_from_beginning(struct vty *vty)
+{
+	vty_beginning_of_line(vty);
+	vty_kill_line(vty);
+}
+
+/* Delete a word before the point. */
+static void vty_forward_kill_word(struct vty *vty)
+{
+	while (vty->cp != vty->length && vty->buf[vty->cp] == ' ')
+		vty_delete_char(vty);
+	while (vty->cp != vty->length && vty->buf[vty->cp] != ' ')
+		vty_delete_char(vty);
+}
+
+/* Delete a word before the point. */
+static void vty_backward_kill_word(struct vty *vty)
+{
+	while (vty->cp > 0 && vty->buf[vty->cp - 1] == ' ')
+		vty_delete_backward_char(vty);
+	while (vty->cp > 0 && vty->buf[vty->cp - 1] != ' ')
+		vty_delete_backward_char(vty);
+}
+
+/* Transpose chars before or at the point. */
+static void vty_transpose_chars(struct vty *vty)
+{
+	char c1, c2;
+
+	/* If length is short or point is near by the beginning of line then
+	   return. */
+	if (vty->length < 2 || vty->cp < 1)
+		return;
+
+	/* In case of point is located at the end of the line. */
+	if (vty->cp == vty->length) {
+		c1 = vty->buf[vty->cp - 1];
+		c2 = vty->buf[vty->cp - 2];
+
+		vty_backward_char(vty);
+		vty_backward_char(vty);
+		vty_self_insert_overwrite(vty, c1);
+		vty_self_insert_overwrite(vty, c2);
+	} else {
+		c1 = vty->buf[vty->cp];
+		c2 = vty->buf[vty->cp - 1];
+
+		vty_backward_char(vty);
+		vty_self_insert_overwrite(vty, c1);
+		vty_self_insert_overwrite(vty, c2);
+	}
+}
+
+/* Do completion at vty interface. */
+static void vty_complete_command(struct vty *vty)
+{
+	int i;
+	int ret;
+	char **matched = NULL;
+	vector vline;
+
+	if (vty->node == AUTH_NODE || vty->node == AUTH_ENABLE_NODE)
+		return;
+
+	vline = cmd_make_strvec(vty->buf);
+	if (vline == NULL)
+		return;
+
+	/* In case of 'help \t'. */
+	if (isspace((int)vty->buf[vty->length - 1]))
+		vector_set(vline, '\0');
+
+	matched = cmd_complete_command(vline, vty, &ret);
+
+	cmd_free_strvec(vline);
+
+	vty_out(vty, "%s", VTY_NEWLINE);
+	switch (ret) {
+	case CMD_ERR_AMBIGUOUS:
+		vty_out(vty, "%% Ambiguous command.%s", VTY_NEWLINE);
+		vty_prompt(vty);
+		vty_redraw_line(vty);
+		break;
+	case CMD_ERR_NO_MATCH:
+		/* vty_out (vty, "%% There is no matched command.%s", VTY_NEWLINE); */
+		vty_prompt(vty);
+		vty_redraw_line(vty);
+		break;
+	case CMD_COMPLETE_FULL_MATCH:
+		vty_prompt(vty);
+		vty_redraw_line(vty);
+		vty_backward_pure_word(vty);
+		vty_insert_word_overwrite(vty, matched[0]);
+		vty_self_insert(vty, ' ');
+		free(matched[0]);
+		break;
+	case CMD_COMPLETE_MATCH:
+		vty_prompt(vty);
+		vty_redraw_line(vty);
+		vty_backward_pure_word(vty);
+		vty_insert_word_overwrite(vty, matched[0]);
+		free(matched[0]);
+		vector_only_index_free(matched);
+		return;
+		break;
+	case CMD_COMPLETE_LIST_MATCH:
+		for (i = 0; matched[i] != NULL; i++) {
+			if (i != 0 && ((i % 6) == 0))
+				vty_out(vty, "%s", VTY_NEWLINE);
+			vty_out(vty, "%-10s ", matched[i]);
+			free(matched[i]);
+		}
+		vty_out(vty, "%s", VTY_NEWLINE);
+
+		vty_prompt(vty);
+		vty_redraw_line(vty);
+		break;
+	case CMD_ERR_NOTHING_TODO:
+		vty_prompt(vty);
+		vty_redraw_line(vty);
+		break;
+	default:
+		break;
+	}
+	if (matched)
+		vector_only_index_free(matched);
+}
+
+static void
+vty_describe_fold(struct vty *vty, int cmd_width,
+		  unsigned int desc_width, struct desc *desc)
+{
+	char *buf;
+	const char *cmd, *p;
+	int pos;
+
+	cmd = desc->cmd[0] == '.' ? desc->cmd + 1 : desc->cmd;
+
+	if (desc_width <= 0) {
+		vty_out(vty, "  %-*s  %s%s", cmd_width, cmd, desc->str,
+			VTY_NEWLINE);
+		return;
+	}
+
+	buf = calloc(1, strlen(desc->str) + 1);
+	if (!buf)
+		return;
+
+	for (p = desc->str; strlen(p) > desc_width; p += pos + 1) {
+		for (pos = desc_width; pos > 0; pos--)
+			if (*(p + pos) == ' ')
+				break;
+
+		if (pos == 0)
+			break;
+
+		strncpy(buf, p, pos);
+		buf[pos] = '\0';
+		vty_out(vty, "  %-*s  %s%s", cmd_width, cmd, buf, VTY_NEWLINE);
+
+		cmd = "";
+	}
+
+	vty_out(vty, "  %-*s  %s%s", cmd_width, cmd, p, VTY_NEWLINE);
+
+	free(buf);
+}
+
+/* Describe matched command function. */
+static void vty_describe_command(struct vty *vty)
+{
+	int ret;
+	vector vline;
+	vector describe;
+	unsigned int i, width, desc_width;
+	struct desc *desc, *desc_cr = NULL;
+
+	vline = cmd_make_strvec(vty->buf);
+
+	/* In case of '> ?'. */
+	if (vline == NULL) {
+		vline = vector_init(1);
+		vector_set(vline, '\0');
+	} else if (isspace((int)vty->buf[vty->length - 1]))
+		vector_set(vline, '\0');
+
+	describe = cmd_describe_command(vline, vty, &ret);
+
+	vty_out(vty, "%s", VTY_NEWLINE);
+
+	/* Ambiguous error. */
+	switch (ret) {
+	case CMD_ERR_AMBIGUOUS:
+		cmd_free_strvec(vline);
+		vty_out(vty, "%% Ambiguous command.%s", VTY_NEWLINE);
+		vty_prompt(vty);
+		vty_redraw_line(vty);
+		return;
+		break;
+	case CMD_ERR_NO_MATCH:
+		cmd_free_strvec(vline);
+		vty_out(vty, "%% There is no matched command.%s", VTY_NEWLINE);
+		vty_prompt(vty);
+		vty_redraw_line(vty);
+		return;
+		break;
+	}
+
+	/* Get width of command string. */
+	width = 0;
+	for (i = 0; i < vector_active(describe); i++)
+		if ((desc = vector_slot(describe, i)) != NULL) {
+			unsigned int len;
+
+			if (desc->cmd[0] == '\0')
+				continue;
+
+			len = strlen(desc->cmd);
+			if (desc->cmd[0] == '.')
+				len--;
+
+			if (width < len)
+				width = len;
+		}
+
+	/* Get width of description string. */
+	desc_width = vty->width - (width + 6);
+
+	/* Print out description. */
+	for (i = 0; i < vector_active(describe); i++)
+		if ((desc = vector_slot(describe, i)) != NULL) {
+			if (desc->cmd[0] == '\0')
+				continue;
+
+			if (strcmp(desc->cmd, "<cr>") == 0) {
+				desc_cr = desc;
+				continue;
+			}
+
+			if (!desc->str)
+				vty_out(vty, "  %-s%s",
+					desc->cmd[0] ==
+					'.' ? desc->cmd + 1 : desc->cmd,
+					VTY_NEWLINE);
+			else if (desc_width >= strlen(desc->str))
+				vty_out(vty, "  %-*s  %s%s", width,
+					desc->cmd[0] ==
+					'.' ? desc->cmd + 1 : desc->cmd,
+					desc->str, VTY_NEWLINE);
+			else
+				vty_describe_fold(vty, width, desc_width, desc);
+
+#if 0
+			vty_out(vty, "  %-*s %s%s", width
+				desc->cmd[0] == '.' ? desc->cmd + 1 : desc->cmd,
+				desc->str ? desc->str : "", VTY_NEWLINE);
+#endif				/* 0 */
+		}
+
+	if ((desc = desc_cr)) {
+		if (!desc->str)
+			vty_out(vty, "  %-s%s",
+				desc->cmd[0] == '.' ? desc->cmd + 1 : desc->cmd,
+				VTY_NEWLINE);
+		else if (desc_width >= strlen(desc->str))
+			vty_out(vty, "  %-*s  %s%s", width,
+				desc->cmd[0] == '.' ? desc->cmd + 1 : desc->cmd,
+				desc->str, VTY_NEWLINE);
+		else
+			vty_describe_fold(vty, width, desc_width, desc);
+	}
+
+	cmd_free_strvec(vline);
+	vector_free(describe);
+
+	vty_prompt(vty);
+	vty_redraw_line(vty);
+}
+
+/* ^C stop current input and do not add command line to the history. */
+static void vty_stop_input(struct vty *vty)
+{
+	vty->cp = vty->length = 0;
+	vty_clear_buf(vty);
+	vty_out(vty, "%s", VTY_NEWLINE);
+
+	switch (vty->node) {
+	case VIEW_NODE:
+	case ENABLE_NODE:
+		/* Nothing to do. */
+		break;
+	case CONFIG_NODE:
+	case INTERFACE_NODE:
+	case ZEBRA_NODE:
+	case RIP_NODE:
+	case RIPNG_NODE:
+	case BGP_NODE:
+	case RMAP_NODE:
+	case OSPF_NODE:
+	case OSPF6_NODE:
+	case ISIS_NODE:
+	case KEYCHAIN_NODE:
+	case KEYCHAIN_KEY_NODE:
+	case MASC_NODE:
+	case VTY_NODE:
+		vty_config_unlock(vty);
+		vty->node = ENABLE_NODE;
+		break;
+	default:
+		/* Unknown node, we have to ignore it. */
+		break;
+	}
+	vty_prompt(vty);
+
+	/* Set history pointer to the latest one. */
+	vty->hp = vty->hindex;
+}
+
+#define CONTROL(X)  ((X) - '@')
+#define VTY_NORMAL     0
+#define VTY_PRE_ESCAPE 1
+#define VTY_ESCAPE     2
+
+/* Escape character command map. */
+static void vty_escape_map(unsigned char c, struct vty *vty)
+{
+	switch (c) {
+	case ('A'):
+		vty_previous_line(vty);
+		break;
+	case ('B'):
+		vty_next_line(vty);
+		break;
+	case ('C'):
+		vty_forward_char(vty);
+		break;
+	case ('D'):
+		vty_backward_char(vty);
+		break;
+	default:
+		break;
+	}
+
+	/* Go back to normal mode. */
+	vty->escape = VTY_NORMAL;
+}
+
+/* Quit print out to the buffer. */
+static void vty_buffer_reset(struct vty *vty)
+{
+	buffer_reset(vty->obuf);
+	vty_prompt(vty);
+	vty_redraw_line(vty);
+}
+
+/* Read data via vty socket. */
+int vty_read(struct vty *vty)
+{
+	int i;
+	int nbytes;
+	unsigned char buf[VTY_READ_BUFSIZ];
+
+	int vty_sock = vty->fd;
+
+	/* Read raw data from socket */
+	if ((nbytes = read(vty->fd, buf, VTY_READ_BUFSIZ)) <= 0) {
+		if (nbytes < 0) {
+			if (ERRNO_IO_RETRY(errno)) {
+				vty_event(VTY_READ, vty_sock, vty);
+				return 0;
+			}
+		}
+		buffer_reset(vty->obuf);
+		vty->status = VTY_CLOSE;
+	}
+
+	for (i = 0; i < nbytes; i++) {
+		if (buf[i] == IAC) {
+			if (!vty->iac) {
+				vty->iac = 1;
+				continue;
+			} else {
+				vty->iac = 0;
+			}
+		}
+
+		if (vty->iac_sb_in_progress && !vty->iac) {
+			if (vty->sb_len < sizeof(vty->sb_buf))
+				vty->sb_buf[vty->sb_len] = buf[i];
+			vty->sb_len++;
+			continue;
+		}
+
+		if (vty->iac) {
+			/* In case of telnet command */
+			int ret = 0;
+			ret = vty_telnet_option(vty, buf + i, nbytes - i);
+			vty->iac = 0;
+			i += ret;
+			continue;
+		}
+
+		if (vty->status == VTY_MORE) {
+			switch (buf[i]) {
+			case CONTROL('C'):
+			case 'q':
+			case 'Q':
+				vty_buffer_reset(vty);
+				break;
+#if 0				/* More line does not work for "show ip bgp".  */
+			case '\n':
+			case '\r':
+				vty->status = VTY_MORELINE;
+				break;
+#endif
+			default:
+				break;
+			}
+			continue;
+		}
+
+		/* Escape character. */
+		if (vty->escape == VTY_ESCAPE) {
+			vty_escape_map(buf[i], vty);
+			continue;
+		}
+
+		/* Pre-escape status. */
+		if (vty->escape == VTY_PRE_ESCAPE) {
+			switch (buf[i]) {
+			case '[':
+				vty->escape = VTY_ESCAPE;
+				break;
+			case 'b':
+				vty_backward_word(vty);
+				vty->escape = VTY_NORMAL;
+				break;
+			case 'f':
+				vty_forward_word(vty);
+				vty->escape = VTY_NORMAL;
+				break;
+			case 'd':
+				vty_forward_kill_word(vty);
+				vty->escape = VTY_NORMAL;
+				break;
+			case CONTROL('H'):
+			case 0x7f:
+				vty_backward_kill_word(vty);
+				vty->escape = VTY_NORMAL;
+				break;
+			default:
+				vty->escape = VTY_NORMAL;
+				break;
+			}
+			continue;
+		}
+
+		switch (buf[i]) {
+		case CONTROL('A'):
+			vty_beginning_of_line(vty);
+			break;
+		case CONTROL('B'):
+			vty_backward_char(vty);
+			break;
+		case CONTROL('C'):
+			vty_stop_input(vty);
+			break;
+		case CONTROL('D'):
+			vty_delete_char(vty);
+			break;
+		case CONTROL('E'):
+			vty_end_of_line(vty);
+			break;
+		case CONTROL('F'):
+			vty_forward_char(vty);
+			break;
+		case CONTROL('H'):
+		case 0x7f:
+			vty_delete_backward_char(vty);
+			break;
+		case CONTROL('K'):
+			vty_kill_line(vty);
+			break;
+		case CONTROL('N'):
+			vty_next_line(vty);
+			break;
+		case CONTROL('P'):
+			vty_previous_line(vty);
+			break;
+		case CONTROL('T'):
+			vty_transpose_chars(vty);
+			break;
+		case CONTROL('U'):
+			vty_kill_line_from_beginning(vty);
+			break;
+		case CONTROL('W'):
+			vty_backward_kill_word(vty);
+			break;
+		case CONTROL('Z'):
+			vty_end_config(vty);
+			break;
+		case '\n':
+		case '\r':
+			vty_out(vty, "%s", VTY_NEWLINE);
+			vty_execute(vty);
+			break;
+		case '\t':
+			vty_complete_command(vty);
+			break;
+		case '?':
+			if (vty->node == AUTH_NODE
+			    || vty->node == AUTH_ENABLE_NODE)
+				vty_self_insert(vty, buf[i]);
+			else
+				vty_describe_command(vty);
+			break;
+		case '\033':
+			if (i + 1 < nbytes && buf[i + 1] == '[') {
+				vty->escape = VTY_ESCAPE;
+				i++;
+			} else
+				vty->escape = VTY_PRE_ESCAPE;
+			break;
+		default:
+			if (buf[i] > 31 && buf[i] < 127)
+				vty_self_insert(vty, buf[i]);
+			break;
+		}
+	}
+
+	/* Check status. */
+	if (vty->status == VTY_CLOSE)
+		vty_close(vty);
+	else {
+		vty_event(VTY_WRITE, vty_sock, vty);
+		vty_event(VTY_READ, vty_sock, vty);
+	}
+	return 0;
+}
+
+/* Create new vty structure. */
+struct vty *
+vty_create (int vty_sock)
+{
+  struct vty *vty;
+
+	struct termios t;
+
+	tcgetattr(vty_sock, &t);
+	cfmakeraw(&t);
+	tcsetattr(vty_sock, TCSANOW, &t);
+
+  /* Allocate new vty structure and set up default values. */
+  vty = vty_new ();
+  vty->fd = vty_sock;
+  vty->type = VTY_TERM;
+  if (no_password_check)
+    {
+      if (host.advanced)
+	vty->node = ENABLE_NODE;
+      else
+	vty->node = VIEW_NODE;
+    }
+  else
+    vty->node = AUTH_NODE;
+  vty->fail = 0;
+  vty->cp = 0;
+  vty_clear_buf (vty);
+  vty->length = 0;
+  memset (vty->hist, 0, sizeof (vty->hist));
+  vty->hp = 0;
+  vty->hindex = 0;
+  vector_set_index (vtyvec, vty_sock, vty);
+  vty->status = VTY_NORMAL;
+  if (host.lines >= 0)
+    vty->lines = host.lines;
+  else
+    vty->lines = -1;
+
+  if (! no_password_check)
+    {
+      /* Vty is not available if password isn't set. */
+      if (host.password == NULL && host.password_encrypt == NULL)
+	{
+	  vty_out (vty, "Vty password is not set.%s", VTY_NEWLINE);
+	  vty->status = VTY_CLOSE;
+	  vty_close (vty);
+	  return NULL;
+	}
+    }
+
+  /* Say hello to the world. */
+  vty_hello (vty);
+  if (! no_password_check)
+    vty_out (vty, "%sUser Access Verification%s%s", VTY_NEWLINE, VTY_NEWLINE, VTY_NEWLINE);
+
+  /* Setting up terminal. */
+  vty_will_echo (vty);
+  vty_will_suppress_go_ahead (vty);
+
+  vty_dont_linemode (vty);
+  vty_do_window_size (vty);
+  /* vty_dont_lflow_ahead (vty); */
+
+  vty_prompt (vty);
+
+  /* Add read/write thread. */
+  vty_event (VTY_WRITE, vty_sock, vty);
+  vty_event (VTY_READ, vty_sock, vty);
+
+  return vty;
+}
+
+DEFUN(config_who, config_who_cmd, "who", "Display who is on vty\n")
+{
+	unsigned int i;
+	struct vty *v;
+
+	for (i = 0; i < vector_active(vtyvec); i++)
+		if ((v = vector_slot(vtyvec, i)) != NULL)
+			vty_out(vty, "%svty[%d] %s",
+				v->config ? "*" : " ", i, VTY_NEWLINE);
+	return CMD_SUCCESS;
+}
+
+/* Move to vty configuration mode. */
+DEFUN(line_vty,
+      line_vty_cmd,
+      "line vty", "Configure a terminal line\n" "Virtual terminal\n")
+{
+	vty->node = VTY_NODE;
+	return CMD_SUCCESS;
+}
+
+/* vty login. */
+DEFUN(vty_login, vty_login_cmd, "login", "Enable password checking\n")
+{
+	no_password_check = 0;
+	return CMD_SUCCESS;
+}
+
+DEFUN(no_vty_login,
+      no_vty_login_cmd, "no login", NO_STR "Enable password checking\n")
+{
+	no_password_check = 1;
+	return CMD_SUCCESS;
+}
+
+DEFUN(service_advanced_vty,
+      service_advanced_vty_cmd,
+      "service advanced-vty",
+      "Set up miscellaneous service\n" "Enable advanced mode vty interface\n")
+{
+	host.advanced = 1;
+	return CMD_SUCCESS;
+}
+
+DEFUN(no_service_advanced_vty,
+      no_service_advanced_vty_cmd,
+      "no service advanced-vty",
+      NO_STR
+      "Set up miscellaneous service\n" "Enable advanced mode vty interface\n")
+{
+	host.advanced = 0;
+	return CMD_SUCCESS;
+}
+
+DEFUN(terminal_monitor,
+      terminal_monitor_cmd,
+      "terminal monitor",
+      "Set terminal line parameters\n"
+      "Copy debug output to the current terminal line\n")
+{
+	vty->monitor = 1;
+	return CMD_SUCCESS;
+}
+
+DEFUN(terminal_no_monitor,
+      terminal_no_monitor_cmd,
+      "terminal no monitor",
+      "Set terminal line parameters\n"
+      NO_STR "Copy debug output to the current terminal line\n")
+{
+	vty->monitor = 0;
+	return CMD_SUCCESS;
+}
+
+DEFUN(show_history,
+      show_history_cmd,
+      "show history", SHOW_STR "Display the session command history\n")
+{
+	int index;
+
+	for (index = vty->hindex + 1; index != vty->hindex;) {
+		if (index == VTY_MAXHIST) {
+			index = 0;
+			continue;
+		}
+
+		if (vty->hist[index] != NULL)
+			vty_out(vty, "  %s%s", vty->hist[index], VTY_NEWLINE);
+
+		index++;
+	}
+
+	return CMD_SUCCESS;
+}
+
+/* Display current configuration. */
+static int vty_config_write(struct vty *vty)
+{
+	vty_out(vty, "line vty%s", VTY_NEWLINE);
+
+	/* login */
+	if (no_password_check)
+		vty_out(vty, " no login%s", VTY_NEWLINE);
+
+	vty_out(vty, "!%s", VTY_NEWLINE);
+
+	return CMD_SUCCESS;
+}
+
+struct cmd_node vty_node = {
+	VTY_NODE,
+	"%s(config-line)# ",
+	1,
+};
+
+/* Reset all VTY status. */
+void vty_reset()
+{
+	unsigned int i;
+	struct vty *vty;
+	struct thread *vty_serv_thread;
+
+	for (i = 0; i < vector_active(vtyvec); i++)
+		if ((vty = vector_slot(vtyvec, i)) != NULL) {
+			buffer_reset(vty->obuf);
+			vty->status = VTY_CLOSE;
+			vty_close(vty);
+		}
+
+	for (i = 0; i < vector_active(Vvty_serv_thread); i++)
+		if ((vty_serv_thread =
+		     vector_slot(Vvty_serv_thread, i)) != NULL) {
+			//thread_cancel (vty_serv_thread);
+			vector_slot(Vvty_serv_thread, i) = NULL;
+			close(i);
+		}
+}
+
+static void vty_save_cwd(void)
+{
+	char cwd[MAXPATHLEN];
+	char *c;
+
+	c = getcwd(cwd, MAXPATHLEN);
+
+	if (!c) {
+		chdir(SYSCONFDIR);
+		getcwd(cwd, MAXPATHLEN);
+	}
+
+	vty_cwd = malloc(strlen(cwd) + 1);
+	strcpy(vty_cwd, cwd);
+}
+
+char *vty_get_cwd()
+{
+	return vty_cwd;
+}
+
+int vty_shell_serv(struct vty *vty)
+{
+	return vty->type == VTY_SHELL_SERV ? 1 : 0;
+}
+
+void vty_init_vtysh()
+{
+	vtyvec = vector_init(VECTOR_MIN_SIZE);
+}
+
+/* Install vty's own commands like `who' command. */
+void vty_init()
+{
+	/* For further configuration read, preserve current directory. */
+	vty_save_cwd();
+
+	vtyvec = vector_init(VECTOR_MIN_SIZE);
+
+	/* Install bgp top node. */
+	install_node(&vty_node, vty_config_write);
+
+	install_element(VIEW_NODE, &config_who_cmd);
+	install_element(VIEW_NODE, &show_history_cmd);
+	install_element(ENABLE_NODE, &config_who_cmd);
+	install_element(CONFIG_NODE, &line_vty_cmd);
+	install_element(CONFIG_NODE, &service_advanced_vty_cmd);
+	install_element(CONFIG_NODE, &no_service_advanced_vty_cmd);
+	install_element(CONFIG_NODE, &show_history_cmd);
+	install_element(ENABLE_NODE, &terminal_monitor_cmd);
+	install_element(ENABLE_NODE, &terminal_no_monitor_cmd);
+	install_element(ENABLE_NODE, &show_history_cmd);
+
+	install_default(VTY_NODE);
+#if 0
+	install_element(VTY_NODE, &vty_login_cmd);
+	install_element(VTY_NODE, &no_vty_login_cmd);
+#endif
+}