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/* $OpenBSD: print-wg.c,v 1.5 2020/07/20 02:24:24 kn Exp $ */
/*
* Copyright (C) 2015-2020 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved.
* Copyright (C) 2019-2020 Matt Dunwoodie <ncon@noconroy.net>
*
* Permission to use, copy, modify, and distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
#include <sys/types.h>
#include <stdio.h>
#include <stddef.h>
#include "interface.h"
#include "extract.h"
#define INITIATION htole32(1)
#define RESPONSE htole32(2)
#define COOKIE htole32(3)
#define DATA htole32(4)
struct wg_initiation {
uint32_t type;
uint32_t sender;
uint8_t fill[140]; /* Includes ephemeral + MAC */
};
struct wg_response {
uint32_t type;
uint32_t sender;
uint32_t receiver;
uint8_t fill[80]; /* Includes ephemeral + MAC */
};
struct wg_cookie {
uint32_t type;
uint32_t receiver;
uint8_t fill[56]; /* Includes nonce + encrypted cookie */
};
struct wg_data {
uint32_t type;
uint32_t receiver;
uint64_t nonce;
/* uint8_t data[variable]; - Variable length data */
uint8_t mac[16];
};
/*
* Check if packet is a WireGuard packet, as WireGuard may run on any port.
*/
uint32_t
wg_match(const u_char *bp, u_int length)
{
uint32_t type;
if (length < sizeof(type))
return 0;
if (snapend - bp < sizeof(type)) {
/*
* we don't have enough bytes to tell if it is wg,
* so don't claim it, and don't claim it's truncated
* wireguard either.
*/
return (0);
}
type = EXTRACT_LE_32BITS(bp);
if (type == INITIATION && length == sizeof(struct wg_initiation))
return INITIATION;
if (type == RESPONSE && length == sizeof(struct wg_response))
return RESPONSE;
if (type == COOKIE && length == sizeof(struct wg_cookie))
return COOKIE;
if (type == DATA && length >= sizeof(struct wg_data))
return DATA;
return 0;
}
/*
* Print WireGuard packet
*/
void
wg_print(const u_char *bp, u_int length)
{
uint32_t type;
uint64_t datalength;
struct wg_initiation *initiation = (void *)bp;
struct wg_response *response = (void *)bp;
struct wg_cookie *cookie = (void *)bp;
struct wg_data *data = (void *)bp;
u_int caplen;
caplen = snapend - bp;
if (caplen < sizeof(type))
goto trunc;
if ((type = wg_match(bp, length)) == 0) {
/* doesn't match */
printf("[wg] unknown");
return;
}
switch (type) {
case INITIATION:
printf("[wg] initiation ");
if (caplen < offsetof(struct wg_initiation, fill))
goto trunc;
printf("from 0x%08x", letoh32(initiation->sender));
break;
case RESPONSE:
printf("[wg] response ");
if (caplen < offsetof(struct wg_response, fill))
goto trunc;
printf("from 0x%08x to 0x%08x",
letoh32(response->sender), letoh32(response->receiver));
break;
case COOKIE:
printf("[wg] cookie ");
if (caplen < offsetof(struct wg_cookie, fill))
goto trunc;
printf(" to 0x%08x", letoh32(cookie->receiver));
break;
case DATA:
datalength = length - sizeof(struct wg_data);
if (datalength != 0)
printf("[wg] data length %llu ", datalength);
else
printf("[wg] keepalive ");
if (caplen < offsetof(struct wg_data, mac))
goto trunc;
printf("to 0x%08x nonce %llu",
letoh32(data->receiver), letoh64(data->nonce));
break;
}
return;
trunc:
printf("[|wg]");
}
|
