OpenVPN
ping.c
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1/*
2 * OpenVPN -- An application to securely tunnel IP networks
3 * over a single TCP/UDP port, with support for SSL/TLS-based
4 * session authentication and key exchange,
5 * packet encryption, packet authentication, and
6 * packet compression.
7 *
8 * Copyright (C) 2002-2025 OpenVPN Inc <sales@openvpn.net>
9 *
10 * This program is free software; you can redistribute it and/or modify
11 * it under the terms of the GNU General Public License version 2
12 * as published by the Free Software Foundation.
13 *
14 * This program is distributed in the hope that it will be useful,
15 * but WITHOUT ANY WARRANTY; without even the implied warranty of
16 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
17 * GNU General Public License for more details.
18 *
19 * You should have received a copy of the GNU General Public License along
20 * with this program; if not, see <https://www.gnu.org/licenses/>.
21 */
22
23#ifdef HAVE_CONFIG_H
24#include "config.h"
25#endif
26
27#include "syshead.h"
28
29#include "ping.h"
30
31#include "memdbg.h"
32
33
34/*
35 * This random string identifies an OpenVPN ping packet.
36 * It should be of sufficient length and randomness
37 * so as not to collide with other tunnel data.
38 *
39 * PING_STRING_SIZE must be sizeof (ping_string)
40 */
41const uint8_t ping_string[] = { 0x2a, 0x18, 0x7b, 0xf3, 0x64, 0x1e, 0xb4, 0xcb,
42 0x07, 0xed, 0x2d, 0x0a, 0x98, 0x1f, 0xc7, 0x48 };
43
44void
46{
47 struct gc_arena gc = gc_new();
49 {
50 case PING_EXIT:
51 msg(M_INFO, "%sInactivity timeout (--ping-exit), exiting", format_common_name(c, &gc));
52 register_signal(c->sig, SIGTERM, "ping-exit");
53 break;
54
55 case PING_RESTART:
56 msg(M_INFO, "%sInactivity timeout (--ping-restart), restarting",
58 register_signal(c->sig, SIGUSR1, "ping-restart");
59 break;
60
61 default:
62 ASSERT(0);
63 }
64 gc_free(&gc);
65}
66
67/*
68 * Should we ping the remote?
69 */
70void
72{
73 c->c2.buf = c->c2.buffers->aux_buf;
77
78 /*
79 * We will treat the ping like any other outgoing packet,
80 * encrypt, sign, etc.
81 */
82 encrypt_sign(c, true);
83 /* Set length to 0, so it won't be counted as activity */
84 c->c2.buf.len = 0;
85 dmsg(D_PING, "SENT PING");
86}
static bool buf_safe(const struct buffer *buf, size_t len)
Definition buffer.h:518
static bool buf_write(struct buffer *dest, const void *src, size_t size)
Definition buffer.h:660
static void gc_free(struct gc_arena *a)
Definition buffer.h:1015
#define buf_init(buf, offset)
Definition buffer.h:209
static struct gc_arena gc_new(void)
Definition buffer.h:1007
#define D_PING
Definition errlevel.h:143
#define M_INFO
Definition errlevel.h:54
void encrypt_sign(struct context *c, bool comp_frag)
Process a data channel packet that will be sent through a VPN tunnel.
Definition forward.c:614
const char * format_common_name(struct context *c, struct gc_arena *gc)
Definition init.c:1281
#define dmsg(flags,...)
Definition error.h:170
#define msg(flags,...)
Definition error.h:150
#define ASSERT(x)
Definition error.h:217
#define PING_RESTART
Definition options.h:356
#define PING_EXIT
Definition options.h:355
const uint8_t ping_string[]
Definition ping.c:41
void trigger_ping_timeout_signal(struct context *c)
Trigger the correct signal on a –ping timeout depending if –ping-exit is set (SIGTERM) or not (SIGUSR...
Definition ping.c:45
void check_ping_send_dowork(struct context *c)
Definition ping.c:71
void register_signal(struct signal_info *si, int signum, const char *signal_text)
Register a soft signal in the signal_info struct si respecting priority.
Definition sig.c:228
int len
Length in bytes of the actual content within the allocated memory.
Definition buffer.h:65
struct frame frame
Definition openvpn.h:248
struct buffer buf
Definition openvpn.h:375
struct context_buffers * buffers
Definition openvpn.h:367
struct buffer aux_buf
Definition openvpn.h:97
Contains all state information for one tunnel.
Definition openvpn.h:474
struct signal_info * sig
Internal error signaling object.
Definition openvpn.h:503
struct context_2 c2
Level 2 context.
Definition openvpn.h:517
struct options options
Options loaded from command line or configuration file.
Definition openvpn.h:475
int payload_size
the maximum size that a payload that our buffers can hold from either tun device or network link.
Definition mtu.h:108
int headroom
the headroom in the buffer, this is choosen to allow all potential header to be added before the pack...
Definition mtu.h:114
struct frame::@8 buf
Garbage collection arena used to keep track of dynamically allocated memory.
Definition buffer.h:116
int ping_rec_timeout_action
Definition options.h:357
struct gc_arena gc
Definition test_ssl.c:154