/*
  *  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) 2002-2018 OpenVPN 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; if not, write to the Free Software Foundation, Inc.,
  *  51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.

  */
 

 #ifdef HAVE_CONFIG_H
 #include "config.h"
 #elif defined(_MSC_VER)
 #include "config-msvc.h"
 #endif
 

 #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");
 }