mirror of
https://github.com/the-tcpdump-group/tcpdump.git
synced 2024-11-30 21:44:49 +08:00
136 lines
3.7 KiB
C
136 lines
3.7 KiB
C
/*
|
|
* This module implements decoding of the Loopback Protocol, originally
|
|
* defined as the Configuration Testing Protocol. It is based on the following
|
|
* specification:
|
|
* http://www.mit.edu/people/jhawk/ctp.pdf
|
|
*
|
|
* Copyright (c) 2014 The TCPDUMP project
|
|
* All rights reserved.
|
|
*
|
|
* Redistribution and use in source and binary forms, with or without
|
|
* modification, are permitted provided that the following conditions
|
|
* are met:
|
|
* 1. Redistributions of source code must retain the above copyright
|
|
* notice, this list of conditions and the following disclaimer.
|
|
* 2. Redistributions in binary form must reproduce the above copyright
|
|
* notice, this list of conditions and the following disclaimer in the
|
|
* documentation and/or other materials provided with the distribution.
|
|
*
|
|
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
|
|
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
|
|
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
|
|
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
|
|
* COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
|
|
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
|
|
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
|
|
* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
|
|
* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
|
|
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
|
|
* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
|
|
* POSSIBILITY OF SUCH DAMAGE.
|
|
*/
|
|
|
|
#ifdef HAVE_CONFIG_H
|
|
#include "config.h"
|
|
#endif
|
|
|
|
#include <netdissect-stdinc.h>
|
|
|
|
#include "netdissect.h"
|
|
#include "extract.h"
|
|
#include "ether.h"
|
|
#include "addrtoname.h"
|
|
|
|
static const char tstr[] = " [|loopback]";
|
|
static const char istr[] = " (invalid)";
|
|
|
|
#define LOOPBACK_REPLY 1
|
|
#define LOOPBACK_FWDDATA 2
|
|
|
|
static const struct tok fcode_str[] = {
|
|
{ LOOPBACK_REPLY, "Reply" },
|
|
{ LOOPBACK_FWDDATA, "Forward Data" },
|
|
{ 0, NULL }
|
|
};
|
|
|
|
static void
|
|
loopback_message_print(netdissect_options *ndo, const u_char *cp, const u_int len)
|
|
{
|
|
const u_char *ep = cp + len;
|
|
uint16_t function;
|
|
|
|
if (len < 2)
|
|
goto invalid;
|
|
/* function */
|
|
ND_TCHECK2(*cp, 2);
|
|
function = EXTRACT_LE_16BITS(cp);
|
|
cp += 2;
|
|
ND_PRINT((ndo, ", %s", tok2str(fcode_str, " invalid (%u)", function)));
|
|
|
|
switch (function) {
|
|
case LOOPBACK_REPLY:
|
|
if (len < 4)
|
|
goto invalid;
|
|
/* receipt number */
|
|
ND_TCHECK2(*cp, 2);
|
|
ND_PRINT((ndo, ", receipt number %u", EXTRACT_LE_16BITS(cp)));
|
|
cp += 2;
|
|
/* data */
|
|
ND_PRINT((ndo, ", data (%u octets)", len - 4));
|
|
ND_TCHECK2(*cp, len - 4);
|
|
break;
|
|
case LOOPBACK_FWDDATA:
|
|
if (len < 8)
|
|
goto invalid;
|
|
/* forwarding address */
|
|
ND_TCHECK2(*cp, ETHER_ADDR_LEN);
|
|
ND_PRINT((ndo, ", forwarding address %s", etheraddr_string(ndo, cp)));
|
|
cp += ETHER_ADDR_LEN;
|
|
/* data */
|
|
ND_PRINT((ndo, ", data (%u octets)", len - 8));
|
|
ND_TCHECK2(*cp, len - 8);
|
|
break;
|
|
default:
|
|
ND_TCHECK2(*cp, len - 2);
|
|
break;
|
|
}
|
|
return;
|
|
|
|
invalid:
|
|
ND_PRINT((ndo, "%s", istr));
|
|
ND_TCHECK2(*cp, ep - cp);
|
|
return;
|
|
trunc:
|
|
ND_PRINT((ndo, "%s", tstr));
|
|
}
|
|
|
|
void
|
|
loopback_print(netdissect_options *ndo, const u_char *cp, const u_int len)
|
|
{
|
|
const u_char *ep = cp + len;
|
|
uint16_t skipCount;
|
|
|
|
ND_PRINT((ndo, "Loopback"));
|
|
if (len < 2)
|
|
goto invalid;
|
|
/* skipCount */
|
|
ND_TCHECK2(*cp, 2);
|
|
skipCount = EXTRACT_LE_16BITS(cp);
|
|
cp += 2;
|
|
ND_PRINT((ndo, ", skipCount %u", skipCount));
|
|
if (skipCount % 8)
|
|
ND_PRINT((ndo, " (bogus)"));
|
|
if (skipCount > len - 2)
|
|
goto invalid;
|
|
loopback_message_print(ndo, cp + skipCount, len - 2 - skipCount);
|
|
return;
|
|
|
|
invalid:
|
|
ND_PRINT((ndo, "%s", istr));
|
|
ND_TCHECK2(*cp, ep - cp);
|
|
return;
|
|
trunc:
|
|
ND_PRINT((ndo, "%s", tstr));
|
|
}
|
|
|