lib: Fix some *bsd build issues introduced by EIGRP code

[mirror_frr.git] / lib / vty.c

/*
 * Virtual terminal [aka TeletYpe] interface routine.
 * Copyright (C) 1997, 98 Kunihiro Ishiguro
 *
 * This file is part of GNU Zebra.
 *
 * GNU Zebra is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License as published by the
 * Free Software Foundation; either version 2, or (at your option) any
 * later version.
 *
 * GNU Zebra is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with GNU Zebra; see the file COPYING.  If not, write to the Free
 * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
 * 02111-1307, USA.
 */

#include <zebra.h>

#include "linklist.h"
#include "thread.h"
#include "buffer.h"
#include <lib/version.h>
#include "command.h"
#include "sockunion.h"
#include "memory.h"
#include "log.h"
#include "prefix.h"
#include "filter.h"
#include "vty.h"
#include "privs.h"
#include "network.h"

#include <arpa/telnet.h>
#include <termios.h>

DEFINE_MTYPE_STATIC(LIB, VTY,         "VTY")
DEFINE_MTYPE_STATIC(LIB, VTY_OUT_BUF, "VTY output buffer")
DEFINE_MTYPE_STATIC(LIB, VTY_HIST,    "VTY history")

/* Vty events */
enum event
{
  VTY_SERV,
  VTY_READ,
  VTY_WRITE,
  VTY_TIMEOUT_RESET,
#ifdef VTYSH
  VTYSH_SERV,
  VTYSH_READ,
  VTYSH_WRITE
#endif /* VTYSH */
};

static void vty_event (enum event, int, struct vty *);

/* Extern host structure from command.c */
extern struct host host;

/* Vector which store each vty structure. */
static vector vtyvec;

/* Vty timeout value. */
static unsigned long vty_timeout_val = VTY_TIMEOUT_DEFAULT;

/* Vty access-class command */
static char *vty_accesslist_name = NULL;

/* Vty access-calss for IPv6. */
static char *vty_ipv6_accesslist_name = NULL;

/* VTY server thread. */
static vector Vvty_serv_thread;

/* Current directory. */
char *vty_cwd = NULL;

/* Configure lock. */
static int vty_config;
static int vty_config_is_lockless = 0;

/* Login password check. */
static int no_password_check = 0;

/* Integrated configuration file path */
char integrate_default[] = SYSCONFDIR INTEGRATE_DEFAULT_CONFIG;

static int do_log_commands = 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 = XREALLOC (MTYPE_VTY_OUT_BUF, 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)
        XFREE (MTYPE_VTY_OUT_BUF, p);
    }

  return len;
}

static int
vty_log_out (struct vty *vty, const char *level, const char *proto_str,
             const char *format, struct timestamp_control *ctl, va_list va)
{
  int ret;
  int len;
  char buf[1024];

  if (!ctl->already_rendered)
    {
      ctl->len = quagga_timestamp(ctl->precision, ctl->buf, sizeof(ctl->buf));
      ctl->already_rendered = 1;
    }
  if (ctl->len+1 >= sizeof(buf))
    return -1;
  memcpy(buf, ctl->buf, len = ctl->len);
  buf[len++] = ' ';
  buf[len] = '\0';

  if (level)
    ret = snprintf(buf+len, sizeof(buf)-len, "%s: %s: ", level, proto_str);
  else
    ret = snprintf(buf+len, sizeof(buf)-len, "%s: ", proto_str);
  if ((ret < 0) || ((size_t)(len += ret) >= sizeof(buf)))
    return -1;

  if (((ret = vsnprintf(buf+len, sizeof(buf)-len, format, va)) < 0) ||
      ((size_t)((len += ret)+2) > sizeof(buf)))
    return -1;

  buf[len++] = '\r';
  buf[len++] = '\n';

  if (write(vty->wfd, buf, len) < 0)
    {
      if (ERRNO_IO_RETRY(errno))
        /* Kernel buffer is full, probably too much debugging output, so just
           drop the data and ignore. */
        return -1;
      /* Fatal I/O error. */
      vty->monitor = 0; /* disable monitoring to avoid infinite recursion */
      zlog_warn("%s: write failed to vty client fd %d, closing: %s",
                __func__, vty->fd, safe_strerror(errno));
      buffer_reset(vty->obuf);
      /* cannot call vty_close, because a parent routine may still try
         to access the vty struct */
      vty->status = VTY_CLOSE;
      shutdown(vty->fd, SHUT_RDWR);
      return -1;
    }
  return 0;
}

/* Output current time to the vty. */
void
vty_time_print (struct vty *vty, int cr)
{
  char buf[QUAGGA_TIMESTAMP_LEN];

  if (quagga_timestamp(0, buf, sizeof(buf)) == 0)
    {
      zlog_info("quagga_timestamp error");
      return;
    }
  if (cr)
    vty_out (vty, "%s\n", buf);
  else
    vty_out (vty, "%s ", buf);

  return;
}

/* 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 ((int)*(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, "%s", 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);
    }
}

/* 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);
}

#if 0 /* Currently not used. */
/* Make don't use lflow vty interface. */
static void
vty_dont_lflow_ahead (struct vty *vty)
{
  unsigned char cmd[] = { IAC, DONT, TELOPT_LFLOW, '\0' };
  vty_out (vty, "%s", cmd);
}
#endif /* 0 */

/* Allocate new vty struct. */
struct vty *
vty_new ()
{
  struct vty *new = XCALLOC (MTYPE_VTY, sizeof (struct vty));

  new->obuf = buffer_new(0);    /* Use default buffer size. */
  new->buf = XCALLOC (MTYPE_VTY, VTY_BUFSIZ);
  new->error_buf = XCALLOC (MTYPE_VTY, VTY_BUFSIZ);
  new->max = VTY_BUFSIZ;

  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->status = VTY_CLOSE;
            }
        }
    }
}

/* Command execution over the vty interface. */
static int
vty_command (struct vty *vty, char *buf)
{
  int ret;
  vector vline;
  const char *protocolname;
  char *cp = NULL;

  /*
   * Log non empty command lines
   */
  if (do_log_commands)
    cp = buf;
  if (cp != NULL)
    {
      /* Skip white spaces. */
      while (isspace ((int) *cp) && *cp != '\0')
        cp++;
    }
  if (cp != NULL && *cp != '\0')
    {
      unsigned i;
      char      vty_str[VTY_BUFSIZ];
      char        prompt_str[VTY_BUFSIZ];

      /* format the base vty info */
      snprintf(vty_str, sizeof(vty_str), "vty[??]@%s", vty->address);
      if (vty)
        for (i = 0; i < vector_active (vtyvec); i++)
          if (vty == vector_slot (vtyvec, i))
            {
              snprintf(vty_str, sizeof(vty_str), "vty[%d]@%s",
                                                 i, vty->address);
              break;
            }

      /* format the prompt */
      snprintf(prompt_str, sizeof(prompt_str), cmd_prompt (vty->node), vty_str);

      /* now log the command */
      zlog_err("%s%s", prompt_str, buf);
    }
  /* Split readline string up into the vector */
  vline = cmd_make_strvec (buf);

  if (vline == NULL)
    return CMD_SUCCESS;

#ifdef CONSUMED_TIME_CHECK
  {
    RUSAGE_T before;
    RUSAGE_T after;
    unsigned long realtime, cputime;

    GETRUSAGE(&before);
#endif /* CONSUMED_TIME_CHECK */

  ret = cmd_execute_command (vline, vty, NULL, 0);

  /* Get the name of the protocol if any */
  protocolname = zlog_protoname();

#ifdef CONSUMED_TIME_CHECK
    GETRUSAGE(&after);
    if ((realtime = thread_consumed_time(&after, &before, &cputime)) >
        CONSUMED_TIME_CHECK)
      /* Warn about CPU hog that must be fixed. */
      zlog_warn("SLOW COMMAND: command took %lums (cpu time %lums): %s",
                realtime/1000, cputime/1000, buf);
  }
#endif /* CONSUMED_TIME_CHECK */

  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, "%% [%s] Unknown command: %s%s", protocolname, buf, 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);
}

/* Basic function to insert character into vty. */
static void
vty_self_insert (struct vty *vty, char c)
{
  int i;
  int length;

  if (vty->length + 1 >= VTY_BUFSIZ)
    return;

  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++;

  vty->buf[vty->length] = '\0';
}

/* Self insert character 'c' in overwrite mode. */
static void
vty_self_insert_overwrite (struct vty *vty, char c)
{
  if (vty->cp == vty->length)
    {
      vty_self_insert (vty, c);
      return;
    }

  vty->buf[vty->cp++] = c;
  vty_write (vty, &c, 1);
}

/**
 * Insert a string into vty->buf at the current cursor position.
 *
 * If the resultant string would be larger than VTY_BUFSIZ it is
 * truncated to fit.
 */
static void
vty_insert_word_overwrite (struct vty *vty, char *str)
{
  if (vty->cp == VTY_BUFSIZ)
    return;

  size_t nwrite = MIN ((int) strlen (str), VTY_BUFSIZ - vty->cp - 1);
  memcpy (&vty->buf[vty->cp], str, nwrite);
  vty->cp += nwrite;
  vty->length = MAX (vty->cp, vty->length);
  vty->buf[vty->length] = '\0';
  vty_write (vty, str, nwrite);
}

/* 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);
}

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;
  vty->buf[vty->length] = '\0';

  /* 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);
  cmd_exit (vty);
  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 EIGRP_NODE:
    case BGP_NODE:
    case BGP_VPNV4_NODE:
    case BGP_VPNV6_NODE:
    case BGP_ENCAP_NODE:
    case BGP_ENCAPV6_NODE:
    case BGP_VRF_POLICY_NODE:
    case BGP_VNC_DEFAULTS_NODE:
    case BGP_VNC_NVE_GROUP_NODE:
    case BGP_VNC_L2_GROUP_NODE:
    case BGP_IPV4_NODE:
    case BGP_IPV4M_NODE:
    case BGP_IPV6_NODE:
    case BGP_IPV6M_NODE:
    case BGP_EVPN_NODE:
    case RMAP_NODE:
    case OSPF_NODE:
    case OSPF6_NODE:
    case LDP_NODE:
    case LDP_IPV4_NODE:
    case LDP_IPV6_NODE:
    case LDP_IPV4_IFACE_NODE:
    case LDP_IPV6_IFACE_NODE:
    case LDP_L2VPN_NODE:
    case LDP_PSEUDOWIRE_NODE:
    case ISIS_NODE:
    case KEYCHAIN_NODE:
    case KEYCHAIN_KEY_NODE:
    case MASC_NODE:
    case PIM_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->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';

  if (vty->node == AUTH_NODE || vty->node == AUTH_ENABLE_NODE)
    return;

  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, NULL);

  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:
      if (!matched[0])
        {
          /* 2016-11-28 equinox -- need to debug, SEGV here */
          vty_out (vty, "%% CLI BUG: FULL_MATCH with NULL str%s", VTY_NEWLINE);
          vty_prompt (vty);
          vty_redraw_line (vty);
          break;
        }
      vty_prompt (vty);
      vty_redraw_line (vty);
      vty_backward_pure_word (vty);
      vty_insert_word_overwrite (vty, matched[0]);
      vty_self_insert (vty, ' ');
      XFREE (MTYPE_TMP, 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]);
      XFREE (MTYPE_TMP, matched[0]);
      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]);
          XFREE (MTYPE_TMP, 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)
    XFREE (MTYPE_TMP, matched);
}

static void
vty_describe_fold (struct vty *vty, int cmd_width,
                   unsigned int desc_width, struct cmd_token *token)
{
  char *buf;
  const char *cmd, *p;
  int pos;

  cmd = token->text;

  if (desc_width <= 0)
    {
      vty_out (vty, "  %-*s  %s%s", cmd_width, cmd, token->desc, VTY_NEWLINE);
      return;
    }

  buf = XCALLOC (MTYPE_TMP, strlen (token->desc) + 1);

  for (p = token->desc; 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);

  XFREE (MTYPE_TMP, 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 cmd_token *token, *token_cr = NULL;

  vline = cmd_make_strvec (vty->buf);

  /* In case of '> ?'. */
  if (vline == NULL)
    {
      vline = vector_init (1);
      vector_set (vline, NULL);
    }
  else
    if (isspace ((int) vty->buf[vty->length - 1]))
      vector_set (vline, NULL);

  describe = cmd_describe_command (vline, vty, &ret);

  vty_out (vty, "%s", VTY_NEWLINE);

  /* Ambiguous error. */
  switch (ret)
    {
    case CMD_ERR_AMBIGUOUS:
      vty_out (vty, "%% Ambiguous command.%s", VTY_NEWLINE);
      goto out;
      break;
    case CMD_ERR_NO_MATCH:
      vty_out (vty, "%% There is no matched command.%s", VTY_NEWLINE);
      goto out;
      break;
    }

  /* Get width of command string. */
  width = 0;
  for (i = 0; i < vector_active (describe); i++)
    if ((token = vector_slot (describe, i)) != NULL)
      {
        unsigned int len;

        if (token->text[0] == '\0')
          continue;

        len = strlen (token->text);

        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 ((token = vector_slot (describe, i)) != NULL)
      {
        if (token->text[0] == '\0')
          continue;

        if (strcmp (token->text, CMD_CR_TEXT) == 0)
          {
            token_cr = token;
            continue;
          }

        if (!token->desc)
          vty_out (vty, "  %-s%s",
                   token->text,
                   VTY_NEWLINE);
        else if (desc_width >= strlen (token->desc))
          vty_out (vty, "  %-*s  %s%s", width,
                   token->text,
                   token->desc, VTY_NEWLINE);
        else
          vty_describe_fold (vty, width, desc_width, token);

#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 ((token = token_cr))
    {
      if (!token->desc)
        vty_out (vty, "  %-s%s",
                 token->text,
                 VTY_NEWLINE);
      else if (desc_width >= strlen (token->desc))
        vty_out (vty, "  %-*s  %s%s", width,
                 token->text,
                 token->desc, VTY_NEWLINE);
      else
        vty_describe_fold (vty, width, desc_width, token);
    }

out:
  cmd_free_strvec (vline);
  if (describe)
    vector_free (describe);

  vty_prompt (vty);
  vty_redraw_line (vty);
}

static void
vty_clear_buf (struct vty *vty)
{
  memset (vty->buf, 0, vty->max);
}

/* ^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 EIGRP_NODE:
    case BGP_NODE:
    case RMAP_NODE:
    case OSPF_NODE:
    case OSPF6_NODE:
    case LDP_NODE:
    case LDP_IPV4_NODE:
    case LDP_IPV6_NODE:
    case LDP_IPV4_IFACE_NODE:
    case LDP_IPV6_IFACE_NODE:
    case LDP_L2VPN_NODE:
    case LDP_PSEUDOWIRE_NODE:
    case ISIS_NODE:
    case KEYCHAIN_NODE:
    case KEYCHAIN_KEY_NODE:
    case MASC_NODE:
    case PIM_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;
}

/* 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])
    XFREE (MTYPE_VTY_HIST, vty->hist[vty->hindex]);
  vty->hist[vty->hindex] = XSTRDUP (MTYPE_VTY_HIST, vty->buf);

  /* History index rotation. */
  vty->hindex++;
  if (vty->hindex == VTY_MAXHIST)
    vty->hindex = 0;

  vty->hp = vty->hindex;
}

/* #define TELNET_OPTION_DEBUG */

/* 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)
              zlog_warn("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)
              zlog_err("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;
}

#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. */
static int
vty_read (struct thread *thread)
{
  int i;
  int nbytes;
  unsigned char buf[VTY_READ_BUFSIZ];

  int vty_sock = THREAD_FD (thread);
  struct vty *vty = THREAD_ARG (thread);
  vty->t_read = NULL;

  /* 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;
            }
          vty->monitor = 0; /* disable monitoring to avoid infinite recursion */
          zlog_warn("%s: read error on vty client fd %d, closing: %s",
                    __func__, vty->fd, safe_strerror(errno));
          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->wfd, vty);
      vty_event (VTY_READ, vty_sock, vty);
    }
  return 0;
}

/* Flush buffer to the vty. */
static int
vty_flush (struct thread *thread)
{
  int erase;
  buffer_status_t flushrc;
  int vty_sock = THREAD_FD (thread);
  struct vty *vty = THREAD_ARG (thread);

  vty->t_write = NULL;

  /* Tempolary disable read thread. */
  if ((vty->lines == 0) && vty->t_read)
    {
      thread_cancel (vty->t_read);
      vty->t_read = NULL;
    }

  /* Function execution continue. */
  erase = ((vty->status == VTY_MORE || vty->status == VTY_MORELINE));

  /* N.B. if width is 0, that means we don't know the window size. */
  if ((vty->lines == 0) || (vty->width == 0) || (vty->height == 0))
    flushrc = buffer_flush_available(vty->obuf, vty_sock);
  else if (vty->status == VTY_MORELINE)
    flushrc = buffer_flush_window(vty->obuf, vty_sock, vty->width,
                                  1, erase, 0);
  else
    flushrc = buffer_flush_window(vty->obuf, vty_sock, vty->width,
                                  vty->lines >= 0 ? vty->lines :
                                                    vty->height,
                                  erase, 0);
  switch (flushrc)
    {
    case BUFFER_ERROR:
      vty->monitor = 0; /* disable monitoring to avoid infinite recursion */
      zlog_warn("buffer_flush failed on vty client fd %d, closing",
                vty->fd);
      buffer_reset(vty->obuf);
      vty_close(vty);
      return 0;
    case BUFFER_EMPTY:
      if (vty->status == VTY_CLOSE)
        vty_close (vty);
      else
        {
          vty->status = VTY_NORMAL;
          if (vty->lines == 0)
            vty_event (VTY_READ, vty_sock, vty);
        }
      break;
    case BUFFER_PENDING:
      /* There is more data waiting to be written. */
      vty->status = VTY_MORE;
      if (vty->lines == 0)
        vty_event (VTY_WRITE, vty_sock, vty);
      break;
    }

  return 0;
}

/* allocate and initialise vty */
static struct vty *
vty_new_init (int vty_sock)
{
  struct vty *vty;

  vty = vty_new ();
  vty->fd = vty_sock;
  vty->wfd = vty_sock;
  vty->type = VTY_TERM;
  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;
  vty->lines = -1;
  vty->iac = 0;
  vty->iac_sb_in_progress = 0;
  vty->sb_len = 0;

  return vty;
}

/* Create new vty structure. */
static struct vty *
vty_create (int vty_sock, union sockunion *su)
{
  char buf[SU_ADDRSTRLEN];
  struct vty *vty;

  sockunion2str(su, buf, SU_ADDRSTRLEN);

  /* Allocate new vty structure and set up default values. */
  vty = vty_new_init (vty_sock);

  /* configurable parameters not part of basic init */
  vty->v_timeout = vty_timeout_val;
  strcpy (vty->address, buf);
  if (no_password_check)
    {
      if (host.advanced)
        vty->node = ENABLE_NODE;
      else
        vty->node = VIEW_NODE;
    }
  if (host.lines >= 0)
    vty->lines = host.lines;

  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;
}

/* create vty for stdio */
static struct termios stdio_orig_termios;
static struct vty *stdio_vty = NULL;
static void (*stdio_vty_atclose)(void);

static void
vty_stdio_reset (void)
{
  if (stdio_vty)
    {
      tcsetattr (0, TCSANOW, &stdio_orig_termios);
      stdio_vty = NULL;

      if (stdio_vty_atclose)
        stdio_vty_atclose ();
      stdio_vty_atclose = NULL;
    }
}

struct vty *
vty_stdio (void (*atclose)())
{
  struct vty *vty;
  struct termios termios;

  /* refuse creating two vtys on stdio */
  if (stdio_vty)
    return NULL;

  vty = stdio_vty = vty_new_init (0);
  stdio_vty_atclose = atclose;
  vty->wfd = 1;

  /* always have stdio vty in a known _unchangeable_ state, don't want config
   * to have any effect here to make sure scripting this works as intended */
  vty->node = ENABLE_NODE;
  vty->v_timeout = 0;
  strcpy (vty->address, "console");

  if (!tcgetattr (0, &stdio_orig_termios))
    {
      termios = stdio_orig_termios;
      termios.c_iflag &= ~(IGNBRK | BRKINT | PARMRK | ISTRIP
                           | INLCR | IGNCR | ICRNL | IXON);
      termios.c_oflag &= ~OPOST;
      termios.c_lflag &= ~(ECHO | ECHONL | ICANON | ISIG | IEXTEN);
      termios.c_cflag &= ~(CSIZE | PARENB);
      termios.c_cflag |= CS8;
      tcsetattr (0, TCSANOW, &termios);
    }

  vty_prompt (vty);

  /* Add read/write thread. */
  vty_event (VTY_WRITE, 1, vty);
  vty_event (VTY_READ, 0, vty);

  return vty;
}

/* Accept connection from the network. */
static int
vty_accept (struct thread *thread)
{
  int vty_sock;
  union sockunion su;
  int ret;
  unsigned int on;
  int accept_sock;
  struct prefix p;
  struct access_list *acl = NULL;
  char buf[SU_ADDRSTRLEN];

  accept_sock = THREAD_FD (thread);

  /* We continue hearing vty socket. */
  vty_event (VTY_SERV, accept_sock, NULL);

  memset (&su, 0, sizeof (union sockunion));

  /* We can handle IPv4 or IPv6 socket. */
  vty_sock = sockunion_accept (accept_sock, &su);
  if (vty_sock < 0)
    {
      zlog_warn ("can't accept vty socket : %s", safe_strerror (errno));
      return -1;
    }
  set_nonblocking(vty_sock);
  set_cloexec(vty_sock);

  sockunion2hostprefix (&su, &p);

  /* VTY's accesslist apply. */
  if (p.family == AF_INET && vty_accesslist_name)
    {
      if ((acl = access_list_lookup (AFI_IP, vty_accesslist_name)) &&
          (access_list_apply (acl, &p) == FILTER_DENY))
        {
          zlog_info ("Vty connection refused from %s",
                     sockunion2str (&su, buf, SU_ADDRSTRLEN));
          close (vty_sock);

          /* continue accepting connections */
          vty_event (VTY_SERV, accept_sock, NULL);

          return 0;
        }
    }

  /* VTY's ipv6 accesslist apply. */
  if (p.family == AF_INET6 && vty_ipv6_accesslist_name)
    {
      if ((acl = access_list_lookup (AFI_IP6, vty_ipv6_accesslist_name)) &&
          (access_list_apply (acl, &p) == FILTER_DENY))
        {
          zlog_info ("Vty connection refused from %s",
                     sockunion2str (&su, buf, SU_ADDRSTRLEN));
          close (vty_sock);

          /* continue accepting connections */
          vty_event (VTY_SERV, accept_sock, NULL);

          return 0;
        }
    }

  on = 1;
  ret = setsockopt (vty_sock, IPPROTO_TCP, TCP_NODELAY,
                    (char *) &on, sizeof (on));
  if (ret < 0)
    zlog_info ("can't set sockopt to vty_sock : %s",
               safe_strerror (errno));

  zlog_info ("Vty connection from %s",
             sockunion2str (&su, buf, SU_ADDRSTRLEN));

  vty_create (vty_sock, &su);

  return 0;
}

static void
vty_serv_sock_addrinfo (const char *hostname, unsigned short port)
{
  int ret;
  struct addrinfo req;
  struct addrinfo *ainfo;
  struct addrinfo *ainfo_save;
  int sock;
  char port_str[BUFSIZ];

  memset (&req, 0, sizeof (struct addrinfo));
  req.ai_flags = AI_PASSIVE;
  req.ai_family = AF_UNSPEC;
  req.ai_socktype = SOCK_STREAM;
  sprintf (port_str, "%d", port);
  port_str[sizeof (port_str) - 1] = '\0';

  ret = getaddrinfo (hostname, port_str, &req, &ainfo);

  if (ret != 0)
    {
      fprintf (stderr, "getaddrinfo failed: %s\n", gai_strerror (ret));
      exit (1);
    }

  ainfo_save = ainfo;

  do
    {
      if (ainfo->ai_family != AF_INET
          && ainfo->ai_family != AF_INET6
          )
        continue;

      sock = socket (ainfo->ai_family, ainfo->ai_socktype, ainfo->ai_protocol);
      if (sock < 0)
        continue;

      sockopt_v6only (ainfo->ai_family, sock);
      sockopt_reuseaddr (sock);
      sockopt_reuseport (sock);
      set_cloexec (sock);

      ret = bind (sock, ainfo->ai_addr, ainfo->ai_addrlen);
      if (ret < 0)
        {
          close (sock); /* Avoid sd leak. */
        continue;
        }

      ret = listen (sock, 3);
      if (ret < 0)
        {
          close (sock); /* Avoid sd leak. */
        continue;
        }

      vty_event (VTY_SERV, sock, NULL);
    }
  while ((ainfo = ainfo->ai_next) != NULL);

  freeaddrinfo (ainfo_save);
}

#ifdef VTYSH
/* For sockaddr_un. */
#include <sys/un.h>

/* VTY shell UNIX domain socket. */
static void
vty_serv_un (const char *path)
{
  int ret;
  int sock, len;
  struct sockaddr_un serv;
  mode_t old_mask;
  struct zprivs_ids_t ids;

  /* First of all, unlink existing socket */
  unlink (path);

  /* Set umask */
  old_mask = umask (0007);

  /* Make UNIX domain socket. */
  sock = socket (AF_UNIX, SOCK_STREAM, 0);
  if (sock < 0)
    {
      zlog_err("Cannot create unix stream socket: %s", safe_strerror(errno));
      return;
    }

  /* Make server socket. */
  memset (&serv, 0, sizeof (struct sockaddr_un));
  serv.sun_family = AF_UNIX;
  strlcpy (serv.sun_path, path, sizeof (serv.sun_path));
#ifdef HAVE_STRUCT_SOCKADDR_UN_SUN_LEN
  len = serv.sun_len = SUN_LEN(&serv);
#else
  len = sizeof (serv.sun_family) + strlen (serv.sun_path);
#endif /* HAVE_STRUCT_SOCKADDR_UN_SUN_LEN */

  set_cloexec (sock);

  ret = bind (sock, (struct sockaddr *) &serv, len);
  if (ret < 0)
    {
      zlog_err("Cannot bind path %s: %s", path, safe_strerror(errno));
      close (sock);     /* Avoid sd leak. */
      return;
    }

  ret = listen (sock, 5);
  if (ret < 0)
    {
      zlog_err("listen(fd %d) failed: %s", sock, safe_strerror(errno));
      close (sock);     /* Avoid sd leak. */
      return;
    }

  umask (old_mask);

  zprivs_get_ids(&ids);

  /* Hack: ids.gid_vty is actually a uint, but we stored -1 in it
     earlier for the case when we don't need to chown the file
     type casting it here to make a compare */
  if ((int)ids.gid_vty > 0)
    {
      /* set group of socket */
      if ( chown (path, -1, ids.gid_vty) )
        {
          zlog_err ("vty_serv_un: could chown socket, %s",
                     safe_strerror (errno) );
        }
    }

  vty_event (VTYSH_SERV, sock, NULL);
}

/* #define VTYSH_DEBUG 1 */

static int
vtysh_accept (struct thread *thread)
{
  int accept_sock;
  int sock;
  int client_len;
  struct sockaddr_un client;
  struct vty *vty;

  accept_sock = THREAD_FD (thread);

  vty_event (VTYSH_SERV, accept_sock, NULL);

  memset (&client, 0, sizeof (struct sockaddr_un));
  client_len = sizeof (struct sockaddr_un);

  sock = accept (accept_sock, (struct sockaddr *) &client,
                 (socklen_t *) &client_len);

  if (sock < 0)
    {
      zlog_warn ("can't accept vty socket : %s", safe_strerror (errno));
      return -1;
    }

  if (set_nonblocking(sock) < 0)
    {
      zlog_warn ("vtysh_accept: could not set vty socket %d to non-blocking,"
                 " %s, closing", sock, safe_strerror (errno));
      close (sock);
      return -1;
    }
  set_cloexec(sock);

#ifdef VTYSH_DEBUG
  printf ("VTY shell accept\n");
#endif /* VTYSH_DEBUG */

  vty = vty_new ();
  vty->fd = sock;
  vty->wfd = sock;
  vty->type = VTY_SHELL_SERV;
  vty->node = VIEW_NODE;

  vty_event (VTYSH_READ, sock, vty);

  return 0;
}

static int
vtysh_flush(struct vty *vty)
{
  switch (buffer_flush_available(vty->obuf, vty->wfd))
    {
    case BUFFER_PENDING:
      vty_event(VTYSH_WRITE, vty->wfd, vty);
      break;
    case BUFFER_ERROR:
      vty->monitor = 0; /* disable monitoring to avoid infinite recursion */
      zlog_warn("%s: write error to fd %d, closing", __func__, vty->fd);
      buffer_reset(vty->obuf);
      vty_close(vty);
      return -1;
      break;
    case BUFFER_EMPTY:
      break;
    }
  return 0;
}

static int
vtysh_read (struct thread *thread)
{
  int ret;
  int sock;
  int nbytes;
  struct vty *vty;
  unsigned char buf[VTY_READ_BUFSIZ];
  unsigned char *p;
  u_char header[4] = {0, 0, 0, 0};

  sock = THREAD_FD (thread);
  vty = THREAD_ARG (thread);
  vty->t_read = NULL;

  if ((nbytes = read (sock, buf, VTY_READ_BUFSIZ)) <= 0)
    {
      if (nbytes < 0)
        {
          if (ERRNO_IO_RETRY(errno))
            {
              vty_event (VTYSH_READ, sock, vty);
              return 0;
            }
          vty->monitor = 0; /* disable monitoring to avoid infinite recursion */
          zlog_warn("%s: read failed on vtysh client fd %d, closing: %s",
                    __func__, sock, safe_strerror(errno));
        }
      buffer_reset(vty->obuf);
      vty_close (vty);
#ifdef VTYSH_DEBUG
      printf ("close vtysh\n");
#endif /* VTYSH_DEBUG */
      return 0;
    }

#ifdef VTYSH_DEBUG
  printf ("line: %.*s\n", nbytes, buf);
#endif /* VTYSH_DEBUG */

  if (vty->length + nbytes >= VTY_BUFSIZ)
    {
      /* Clear command line buffer. */
      vty->cp = vty->length = 0;
      vty_clear_buf (vty);
      vty_out (vty, "%% Command is too long.%s", VTY_NEWLINE);
    }
  else
    {
      for (p = buf; p < buf+nbytes; p++)
        {
          vty->buf[vty->length++] = *p;
          if (*p == '\0')
            {
              /* Pass this line to parser. */
              ret = vty_execute (vty);
              /* Note that vty_execute clears the command buffer and resets
                 vty->length to 0. */

              /* Return result. */
#ifdef VTYSH_DEBUG
              printf ("result: %d\n", ret);
              printf ("vtysh node: %d\n", vty->node);
#endif /* VTYSH_DEBUG */

              /* hack for asynchronous "write integrated"
               * - other commands in "buf" will be ditched
               * - input during pending config-write is "unsupported" */
              if (ret == CMD_SUSPEND)
                break;

              /* warning: watchquagga hardcodes this result write */
              header[3] = ret;
              buffer_put(vty->obuf, header, 4);

              if (!vty->t_write && (vtysh_flush(vty) < 0))
                /* Try to flush results; exit if a write error occurs. */
                return 0;
            }
        }
    }

  vty_event (VTYSH_READ, sock, vty);

  return 0;
}

static int
vtysh_write (struct thread *thread)
{
  struct vty *vty = THREAD_ARG (thread);

  vty->t_write = NULL;
  vtysh_flush(vty);
  return 0;
}

#endif /* VTYSH */

/* Determine address family to bind. */
void
vty_serv_sock (const char *addr, unsigned short port, const char *path)
{
  /* If port is set to 0, do not listen on TCP/IP at all! */
  if (port)
    vty_serv_sock_addrinfo (addr, port);

#ifdef VTYSH
  vty_serv_un (path);
#endif /* VTYSH */
}

/* Close vty interface.  Warning: call this only from functions that
   will be careful not to access the vty afterwards (since it has
   now been freed).  This is safest from top-level functions (called
   directly by the thread dispatcher). */
void
vty_close (struct vty *vty)
{
  int i;
  bool was_stdio = false;

  /* Cancel threads.*/
  if (vty->t_read)
    thread_cancel (vty->t_read);
  if (vty->t_write)
    thread_cancel (vty->t_write);
  if (vty->t_timeout)
    thread_cancel (vty->t_timeout);

  /* Flush buffer. */
  buffer_flush_all (vty->obuf, vty->wfd);

  /* Free input buffer. */
  buffer_free (vty->obuf);

  /* Free command history. */
  for (i = 0; i < VTY_MAXHIST; i++)
    if (vty->hist[i])
      XFREE (MTYPE_VTY_HIST, vty->hist[i]);

  /* Unset vector. */
  vector_unset (vtyvec, vty->fd);

  if (vty->wfd > 0 && vty->type == VTY_FILE)
    fsync (vty->wfd);

  /* Close socket. */
  if (vty->fd > 0)
    {
      close (vty->fd);
      if (vty->wfd > 0 && vty->wfd != vty->fd)
        close (vty->wfd);
    }
  else
    was_stdio = true;

  if (vty->buf)
    XFREE (MTYPE_VTY, vty->buf);

  if (vty->error_buf)
    XFREE (MTYPE_VTY, vty->error_buf);

  /* Check configure. */
  vty_config_unlock (vty);

  /* OK free vty. */
  XFREE (MTYPE_VTY, vty);

  if (was_stdio)
    vty_stdio_reset ();
}

/* When time out occur output message then close connection. */
static int
vty_timeout (struct thread *thread)
{
  struct vty *vty;

  vty = THREAD_ARG (thread);
  vty->t_timeout = NULL;
  vty->v_timeout = 0;

  /* Clear buffer*/
  buffer_reset (vty->obuf);
  vty_out (vty, "%sVty connection is timed out.%s", VTY_NEWLINE, VTY_NEWLINE);

  /* Close connection. */
  vty->status = VTY_CLOSE;
  vty_close (vty);

  return 0;
}

/* Read up configuration file from file_name. */
static void
vty_read_file (FILE *confp)
{
  int ret;
  struct vty *vty;
  unsigned int line_num = 0;

  vty = vty_new ();
  vty->wfd = dup(STDERR_FILENO); /* vty_close() will close this */
  if (vty->wfd < 0)
  {
    /* Fine, we couldn't make a new fd. vty_close doesn't close stdout. */
    vty->wfd = STDOUT_FILENO;
  }
  vty->fd = STDIN_FILENO;
  vty->type = VTY_FILE;
  vty->node = CONFIG_NODE;

  /* Execute configuration file */
  ret = config_from_file (vty, confp, &line_num);

  /* Flush any previous errors before printing messages below */
  buffer_flush_all (vty->obuf, vty->fd);

  if ( !((ret == CMD_SUCCESS) || (ret == CMD_ERR_NOTHING_TODO)) )
    {
      const char *message = NULL;
      switch (ret)
       {
         case CMD_ERR_AMBIGUOUS:
           message = "*** Error reading config: Ambiguous command.";
           break;
         case CMD_ERR_NO_MATCH:
           message = "*** Error reading config: There is no such command.";
           break;
       }
      fprintf (stderr, "%s\n", message);
      zlog_err ("%s", message);
      fprintf (stderr, "*** Error occurred processing line %u, below:\n%s\n",
                       line_num, vty->error_buf);
      zlog_err ("*** Error occurred processing line %u, below:\n%s",
                      line_num, vty->error_buf);
    }

  vty_close (vty);
}

static FILE *
vty_use_backup_config (const char *fullpath)
{
  char *fullpath_sav, *fullpath_tmp;
  FILE *ret = NULL;
  int tmp, sav;
  int c;
  char buffer[512];

  fullpath_sav = malloc (strlen (fullpath) + strlen (CONF_BACKUP_EXT) + 1);
  strcpy (fullpath_sav, fullpath);
  strcat (fullpath_sav, CONF_BACKUP_EXT);

  sav = open (fullpath_sav, O_RDONLY);
  if (sav < 0)
    {
      free (fullpath_sav);
      return NULL;
    }

  fullpath_tmp = malloc (strlen (fullpath) + 8);
  sprintf (fullpath_tmp, "%s.XXXXXX", fullpath);

  /* Open file to configuration write. */
  tmp = mkstemp (fullpath_tmp);
  if (tmp < 0)
    goto out_close_sav;

  if (fchmod (tmp, CONFIGFILE_MASK) != 0)
    goto out_close;

  while((c = read (sav, buffer, 512)) > 0)
    {
      if (write (tmp, buffer, c) <= 0)
        goto out_close;
    }
  close (sav);
  close (tmp);

  if (rename (fullpath_tmp, fullpath) == 0)
    ret = fopen (fullpath, "r");
  else
    unlink (fullpath_tmp);

  if (0)
    {
out_close:
      close (tmp);
      unlink (fullpath_tmp);
out_close_sav:
      close (sav);
    }

  free (fullpath_sav);
  free (fullpath_tmp);
  return ret;
}

/* Read up configuration file from file_name. */
void
vty_read_config (const char *config_file,
                 char *config_default_dir)
{
  char cwd[MAXPATHLEN];
  FILE *confp = NULL;
  const char *fullpath;
  char *tmp = NULL;

  /* If -f flag specified. */
  if (config_file != NULL)
    {
      if (! IS_DIRECTORY_SEP (config_file[0]))
        {
          if (getcwd (cwd, MAXPATHLEN) == NULL)
            {
              fprintf (stderr, "Failure to determine Current Working Directory %d!\n", errno);
              exit (1);
            }
          tmp = XMALLOC (MTYPE_TMP,
                              strlen (cwd) + strlen (config_file) + 2);
          sprintf (tmp, "%s/%s", cwd, config_file);
          fullpath = tmp;
        }
      else
        fullpath = config_file;

      confp = fopen (fullpath, "r");

      if (confp == NULL)
        {
          fprintf (stderr, "%s: failed to open configuration file %s: %s\n",
                   __func__, fullpath, safe_strerror (errno));

          confp = vty_use_backup_config (fullpath);
          if (confp)
            fprintf (stderr, "WARNING: using backup configuration file!\n");
          else
            {
              fprintf (stderr, "can't open configuration file [%s]\n",
                       config_file);
              exit(1);
            }
        }
    }
  else
    {

      host_config_set (config_default_dir);

#ifdef VTYSH
      int ret;
      struct stat conf_stat;

      /* !!!!PLEASE LEAVE!!!!
       * This is NEEDED for use with vtysh -b, or else you can get
       * a real configuration food fight with a lot garbage in the
       * merged configuration file it creates coming from the per
       * daemon configuration files.  This also allows the daemons
       * to start if there default configuration file is not
       * present or ignore them, as needed when using vtysh -b to
       * configure the daemons at boot - MAG
       */

      /* Stat for vtysh Zebra.conf, if found startup and wait for
       * boot configuration
       */

      if ( strstr(config_default_dir, "vtysh") == NULL)
        {
          ret = stat (integrate_default, &conf_stat);
          if (ret >= 0)
            goto tmp_free_and_out;
        }
#endif /* VTYSH */
      confp = fopen (config_default_dir, "r");
      if (confp == NULL)
        {
          fprintf (stderr, "%s: failed to open configuration file %s: %s\n",
                   __func__, config_default_dir, safe_strerror (errno));

          confp = vty_use_backup_config (config_default_dir);
          if (confp)
            {
              fprintf (stderr, "WARNING: using backup configuration file!\n");
              fullpath = config_default_dir;
            }
          else
            {
              fprintf (stderr, "can't open configuration file [%s]\n",
                       config_default_dir);
              goto tmp_free_and_out;
            }
        }
      else
        fullpath = config_default_dir;
    }

  vty_read_file (confp);

  fclose (confp);

  host_config_set (fullpath);

tmp_free_and_out:
  if (tmp)
    XFREE (MTYPE_TMP, tmp);
}

/* Small utility function which output log to the VTY. */
void
vty_log (const char *level, const char *proto_str,
         const char *format, struct timestamp_control *ctl, va_list va)
{
  unsigned int i;
  struct vty *vty;

  if (!vtyvec)
    return;

  for (i = 0; i < vector_active (vtyvec); i++)
    if ((vty = vector_slot (vtyvec, i)) != NULL)
      if (vty->monitor)
        {
          va_list ac;
          va_copy(ac, va);
          vty_log_out (vty, level, proto_str, format, ctl, ac);
          va_end(ac);
        }
}

/* Async-signal-safe version of vty_log for fixed strings. */
void
vty_log_fixed (char *buf, size_t len)
{
  unsigned int i;
  struct iovec iov[2];
  char crlf[4] = "\r\n";

  /* vty may not have been initialised */
  if (!vtyvec)
    return;

  iov[0].iov_base = buf;
  iov[0].iov_len = len;
  iov[1].iov_base = crlf;
  iov[1].iov_len = 2;

  for (i = 0; i < vector_active (vtyvec); i++)
    {
      struct vty *vty;
      if (((vty = vector_slot (vtyvec, i)) != NULL) && vty->monitor)
        /* N.B. We don't care about the return code, since process is
           most likely just about to die anyway. */
        if (writev(vty->wfd, iov, 2) == -1)
          {
            fprintf(stderr, "Failure to writev: %d\n", errno);
            exit(-1);
          }
    }
}

int
vty_config_lock (struct vty *vty)
{
  if (vty_config_is_lockless)
    return 1;
  if (vty_config == 0)
    {
      vty->config = 1;
      vty_config = 1;
    }
  return vty->config;
}

int
vty_config_unlock (struct vty *vty)
{
  if (vty_config_is_lockless)
    return 0;
  if (vty_config == 1 && vty->config == 1)
    {
      vty->config = 0;
      vty_config = 0;
    }
  return vty->config;
}

void
vty_config_lockless (void)
{
  vty_config_is_lockless = 1;
}

/* Master of the threads. */
static struct thread_master *vty_master;

static void
vty_event (enum event event, int sock, struct vty *vty)
{
  struct thread *vty_serv_thread;

  switch (event)
    {
    case VTY_SERV:
      vty_serv_thread = thread_add_read (vty_master, vty_accept, vty, sock);
      vector_set_index (Vvty_serv_thread, sock, vty_serv_thread);
      break;
#ifdef VTYSH
    case VTYSH_SERV:
      vty_serv_thread = thread_add_read (vty_master, vtysh_accept, vty, sock);
      vector_set_index (Vvty_serv_thread, sock, vty_serv_thread);
      break;
    case VTYSH_READ:
      vty->t_read = thread_add_read (vty_master, vtysh_read, vty, sock);
      break;
    case VTYSH_WRITE:
      vty->t_write = thread_add_write (vty_master, vtysh_write, vty, sock);
      break;
#endif /* VTYSH */
    case VTY_READ:
      vty->t_read = thread_add_read (vty_master, vty_read, vty, sock);

      /* Time out treatment. */
      if (vty->v_timeout)
        {
          if (vty->t_timeout)
            thread_cancel (vty->t_timeout);
          vty->t_timeout =
            thread_add_timer (vty_master, vty_timeout, vty, vty->v_timeout);
        }
      break;
    case VTY_WRITE:
      if (! vty->t_write)
        vty->t_write = thread_add_write (vty_master, vty_flush, vty, sock);
      break;
    case VTY_TIMEOUT_RESET:
      if (vty->t_timeout)
        {
          thread_cancel (vty->t_timeout);
          vty->t_timeout = NULL;
        }
      if (vty->v_timeout)
        {
          vty->t_timeout =
            thread_add_timer (vty_master, vty_timeout, vty, vty->v_timeout);
        }
      break;
    }
}

DEFUN_NOSH (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] connected from %s.%s",
               v->config ? "*" : " ",
               i, v->address, VTY_NEWLINE);
  return CMD_SUCCESS;
}

/* Move to vty configuration mode. */
DEFUN_NOSH (line_vty,
       line_vty_cmd,
       "line vty",
       "Configure a terminal line\n"
       "Virtual terminal\n")
{
  vty->node = VTY_NODE;
  return CMD_SUCCESS;
}

/* Set time out value. */
static int
exec_timeout (struct vty *vty, const char *min_str, const char *sec_str)
{
  unsigned long timeout = 0;

  /* min_str and sec_str are already checked by parser.  So it must be
     all digit string. */
  if (min_str)
    {
      timeout = strtol (min_str, NULL, 10);
      timeout *= 60;
    }
  if (sec_str)
    timeout += strtol (sec_str, NULL, 10);

  vty_timeout_val = timeout;
  vty->v_timeout = timeout;
  vty_event (VTY_TIMEOUT_RESET, 0, vty);


  return CMD_SUCCESS;
}

DEFUN (exec_timeout_min,
       exec_timeout_min_cmd,
       "exec-timeout (0-35791)",
       "Set timeout value\n"
       "Timeout value in minutes\n")
{
  int idx_number = 1;
  return exec_timeout (vty, argv[idx_number]->arg, NULL);
}

DEFUN (exec_timeout_sec,
       exec_timeout_sec_cmd,
       "exec-timeout (0-35791) (0-2147483)",
       "Set the EXEC timeout\n"
       "Timeout in minutes\n"
       "Timeout in seconds\n")
{
  int idx_number = 1;
  int idx_number_2 = 2;
  return exec_timeout (vty, argv[idx_number]->arg, argv[idx_number_2]->arg);
}

DEFUN (no_exec_timeout,
       no_exec_timeout_cmd,
       "no exec-timeout",
       NO_STR
       "Set the EXEC timeout\n")
{
  return exec_timeout (vty, NULL, NULL);
}

/* Set vty access class. */
DEFUN (vty_access_class,
       vty_access_class_cmd,
       "access-class WORD",
       "Filter connections based on an IP access list\n"
       "IP access list\n")
{
  int idx_word = 1;
  if (vty_accesslist_name)
    XFREE(MTYPE_VTY, vty_accesslist_name);

  vty_accesslist_name = XSTRDUP(MTYPE_VTY, argv[idx_word]->arg);

  return CMD_SUCCESS;
}

/* Clear vty access class. */
DEFUN (no_vty_access_class,
       no_vty_access_class_cmd,
       "no access-class [WORD]",
       NO_STR
       "Filter connections based on an IP access list\n"
       "IP access list\n")
{
  int idx_word = 2;
  const char *accesslist = (argc == 3) ? argv[idx_word]->arg : NULL;
  if (! vty_accesslist_name || (argc == 3 && strcmp(vty_accesslist_name, accesslist)))
    {
      vty_out (vty, "Access-class is not currently applied to vty%s",
               VTY_NEWLINE);
      return CMD_WARNING;
    }

  XFREE(MTYPE_VTY, vty_accesslist_name);

  vty_accesslist_name = NULL;

  return CMD_SUCCESS;
}

/* Set vty access class. */
DEFUN (vty_ipv6_access_class,
       vty_ipv6_access_class_cmd,
       "ipv6 access-class WORD",
       IPV6_STR
       "Filter connections based on an IP access list\n"
       "IPv6 access list\n")
{
  int idx_word = 2;
  if (vty_ipv6_accesslist_name)
    XFREE(MTYPE_VTY, vty_ipv6_accesslist_name);

  vty_ipv6_accesslist_name = XSTRDUP(MTYPE_VTY, argv[idx_word]->arg);

  return CMD_SUCCESS;
}

/* Clear vty access class. */
DEFUN (no_vty_ipv6_access_class,
       no_vty_ipv6_access_class_cmd,
       "no ipv6 access-class [WORD]",
       NO_STR
       IPV6_STR
       "Filter connections based on an IP access list\n"
       "IPv6 access list\n")
{
  int idx_word = 3;
  const char *accesslist = (argc == 4) ? argv[idx_word]->arg : NULL;

  if (! vty_ipv6_accesslist_name ||
      (argc == 4 && strcmp(vty_ipv6_accesslist_name, accesslist)))
    {
      vty_out (vty, "IPv6 access-class is not currently applied to vty%s",
               VTY_NEWLINE);
      return CMD_WARNING;
    }

  XFREE(MTYPE_VTY, vty_ipv6_accesslist_name);

  vty_ipv6_accesslist_name = NULL;

  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_NOSH (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_NOSH (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_NOSH (no_terminal_monitor,
       no_terminal_monitor_cmd,
       "no terminal monitor",
       NO_STR
       "Set terminal line parameters\n"
       "Copy debug output to the current terminal line\n")
{
  return terminal_no_monitor (self, vty, argc, argv);
}


DEFUN_NOSH (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;
}

/* vty login. */
DEFUN (log_commands,
       log_commands_cmd,
       "log commands",
       "Logging control\n"
       "Log all commands (can't be unset without restart)\n")
{
  do_log_commands = 1;
  return CMD_SUCCESS;
}

/* Display current configuration. */
static int
vty_config_write (struct vty *vty)
{
  vty_out (vty, "line vty%s", VTY_NEWLINE);

  if (vty_accesslist_name)
    vty_out (vty, " access-class %s%s",
             vty_accesslist_name, VTY_NEWLINE);

  if (vty_ipv6_accesslist_name)
    vty_out (vty, " ipv6 access-class %s%s",
             vty_ipv6_accesslist_name, VTY_NEWLINE);

  /* exec-timeout */
  if (vty_timeout_val != VTY_TIMEOUT_DEFAULT)
    vty_out (vty, " exec-timeout %ld %ld%s",
             vty_timeout_val / 60,
             vty_timeout_val % 60, VTY_NEWLINE);

  /* login */
  if (no_password_check)
    vty_out (vty, " no login%s", VTY_NEWLINE);

  if (do_log_commands)
    vty_out (vty, "log commands%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);
      }

  vty_timeout_val = VTY_TIMEOUT_DEFAULT;

  if (vty_accesslist_name)
    {
      XFREE(MTYPE_VTY, vty_accesslist_name);
      vty_accesslist_name = NULL;
    }

  if (vty_ipv6_accesslist_name)
    {
      XFREE(MTYPE_VTY, vty_ipv6_accesslist_name);
      vty_ipv6_accesslist_name = NULL;
    }
}

static void
vty_save_cwd (void)
{
  char cwd[MAXPATHLEN];
  char *c;

  c = getcwd (cwd, MAXPATHLEN);

  if (!c)
    {
      /*
       * At this point if these go wrong, more than likely
       * the whole world is coming down around us
       * Hence not worrying about it too much.
       */
      if (!chdir (SYSCONFDIR))
        {
          fprintf(stderr, "Failure to chdir to %s, errno: %d\n", SYSCONFDIR, errno);
          exit(-1);
        }
      if (getcwd (cwd, MAXPATHLEN) == NULL)
        {
          fprintf(stderr, "Failure to getcwd, errno: %d\n", errno);
          exit(-1);
        }
    }

  vty_cwd = XMALLOC (MTYPE_TMP, strlen (cwd) + 1);
  strcpy (vty_cwd, cwd);
}

char *
vty_get_cwd ()
{
  return vty_cwd;
}

int
vty_shell (struct vty *vty)
{
  return vty->type == VTY_SHELL ? 1 : 0;
}

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 (struct thread_master *master_thread)
{
  /* For further configuration read, preserve current directory. */
  vty_save_cwd ();

  vtyvec = vector_init (VECTOR_MIN_SIZE);

  vty_master = master_thread;

  atexit (vty_stdio_reset);

  /* Initilize server thread vector. */
  Vvty_serv_thread = 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 (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 (CONFIG_NODE, &log_commands_cmd);
  install_element (ENABLE_NODE, &terminal_monitor_cmd);
  install_element (ENABLE_NODE, &terminal_no_monitor_cmd);
  install_element (ENABLE_NODE, &no_terminal_monitor_cmd);

  install_default (VTY_NODE);
  install_element (VTY_NODE, &exec_timeout_min_cmd);
  install_element (VTY_NODE, &exec_timeout_sec_cmd);
  install_element (VTY_NODE, &no_exec_timeout_cmd);
  install_element (VTY_NODE, &vty_access_class_cmd);
  install_element (VTY_NODE, &no_vty_access_class_cmd);
  install_element (VTY_NODE, &vty_login_cmd);
  install_element (VTY_NODE, &no_vty_login_cmd);
  install_element (VTY_NODE, &vty_ipv6_access_class_cmd);
  install_element (VTY_NODE, &no_vty_ipv6_access_class_cmd);
}

void
vty_terminate (void)
{
  if (vty_cwd)
    XFREE (MTYPE_TMP, vty_cwd);

  if (vtyvec && Vvty_serv_thread)
    {
      vty_reset ();
      vector_free (vtyvec);
      vector_free (Vvty_serv_thread);
      vtyvec = NULL;
      Vvty_serv_thread = NULL;
    }
}

/* Utility functions to get arguments from commands generated
   by the xml2cli.pl script. */
const char *
vty_get_arg_value (struct vty_arg *args[], const char *arg)
{
  while (*args)
    {
      if (strcmp ((*args)->name, arg) == 0)
        return (*args)->value;
      args++;
    }
  return NULL;
}

struct vty_arg *
vty_get_arg (struct vty_arg *args[], const char *arg)
{
  while (*args)
    {
      if (strcmp ((*args)->name, arg) == 0)
        return *args;
      args++;
    }
  return NULL;
}