/*
  *  OpenVPN -- An application to securely tunnel IP networks
  *             over a single TCP/UDP port, with support for SSL/TLS-based
  *             session authentication and key exchange,
  *             packet encryption, packet authentication, and
  *             packet compression.
  *

  *  Copyright (C) 2002-2010 OpenVPN Technologies, Inc. <sales@openvpn.net>

  *
  *  This program is free software; you can redistribute it and/or modify
  *  it under the terms of the GNU General Public License version 2
  *  as published by the Free Software Foundation.
  *
  *  This program 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 this program (see the file COPYING included with this
  *  distribution); if not, write to the Free Software Foundation, Inc.,
  *  59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  */
 
 #include "syshead.h"
 
 #include "ping.h"
 
 #include "memdbg.h"
 
 #include "ping-inline.h"
 
 /*
  * This random string identifies an OpenVPN ping packet.
  * It should be of sufficient length and randomness
  * so as not to collide with other tunnel data.
  *
  * PING_STRING_SIZE must be sizeof (ping_string)
  */
 const uint8_t ping_string[] = {
   0x2a, 0x18, 0x7b, 0xf3, 0x64, 0x1e, 0xb4, 0xcb,
   0x07, 0xed, 0x2d, 0x0a, 0x98, 0x1f, 0xc7, 0x48
 };
 
 /*
  * Should we exit or restart due to ping (or other authenticated packet)
  * not received in n seconds?
  */
 void
 check_ping_restart_dowork (struct context *c)
 {
   struct gc_arena gc = gc_new ();
   switch (c->options.ping_rec_timeout_action)
     {
     case PING_EXIT:
       msg (M_INFO, "%sInactivity timeout (--ping-exit), exiting",
 	   format_common_name (c, &gc));
       c->sig->signal_received = SIGTERM;
       c->sig->signal_text = "ping-exit";
       break;
     case PING_RESTART:
       msg (M_INFO, "%sInactivity timeout (--ping-restart), restarting",
 	   format_common_name (c, &gc));
       c->sig->signal_received = SIGUSR1; /* SOFT-SIGUSR1 -- Ping Restart */
       c->sig->signal_text = "ping-restart";
       break;
     default:
       ASSERT (0);
     }
   gc_free (&gc);
 }
 
 /*
  * Should we ping the remote?
  */
 void
 check_ping_send_dowork (struct context *c)
 {
   c->c2.buf = c->c2.buffers->aux_buf;
   ASSERT (buf_init (&c->c2.buf, FRAME_HEADROOM (&c->c2.frame)));
   ASSERT (buf_safe (&c->c2.buf, MAX_RW_SIZE_TUN (&c->c2.frame)));
   ASSERT (buf_write (&c->c2.buf, ping_string, sizeof (ping_string)));
 
   /*
    * We will treat the ping like any other outgoing packet,
    * encrypt, sign, etc.
    */
   encrypt_sign (c, true);

   /* Set length to 0, so it won't be counted as activity */
   c->c2.buf.len = 0;

   dmsg (D_PING, "SENT PING");

 }