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wireshark/packet-ethertype.c

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/* ethertype.c
* Routines for calling the right protocol for the ethertype.
*
* $Id: packet-ethertype.c,v 1.20 2001/11/13 23:55:29 gram Exp $
*
* Gilbert Ramirez <gram@alumni.rice.edu>
*
* Ethereal - Network traffic analyzer
* By Gerald Combs <gerald@zing.org>
* Copyright 1998 Gerald Combs
*
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
*
* 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., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*/
#ifdef HAVE_CONFIG_H
# include "config.h"
#endif
#ifdef HAVE_SYS_TYPES_H
# include <sys/types.h>
#endif
#include <glib.h>
#include "packet.h"
#include "packet-ip.h"
#include "packet-ipx.h"
#include "packet-vlan.h"
#include "packet-vines.h"
#include "etypes.h"
#include "ppptypes.h"
static dissector_table_t ethertype_dissector_table;
const value_string etype_vals[] = {
{ETHERTYPE_IP, "IP" },
{ETHERTYPE_IPv6, "IPv6" },
{ETHERTYPE_X25L3, "X.25 Layer 3" },
{ETHERTYPE_ARP, "ARP" },
{ETHERTYPE_REVARP, "RARP" },
{ETHERTYPE_DEC_LB, "DEC LanBridge" },
{ETHERTYPE_ATALK, "Appletalk" },
{ETHERTYPE_AARP, "AARP" },
{ETHERTYPE_IPX, "Netware IPX/SPX" },
{ETHERTYPE_VINES, "Vines" },
{ETHERTYPE_TRAIN, "Netmon Train" },
{ETHERTYPE_LOOP, "Loopback" }, /* Ethernet Loopback */
{ETHERTYPE_WCP, "Wellfleet Compression Protocol" },
{ETHERTYPE_PPPOED, "PPPoE Discovery" },
{ETHERTYPE_PPPOES, "PPPoE Session" },
{ETHERTYPE_VLAN, "802.1Q Virtual LAN" },
{ETHERTYPE_EAPOL, "802.1X Authentication" },
{ETHERTYPE_MPLS, "MPLS label switched packet" },
{ETHERTYPE_MPLS_MULTI, "MPLS multicast label switched packet" },
{ETHERTYPE_3C_NBP_DGRAM, "3Com NBP Datagram" },
{ETHERTYPE_DEC, "DEC proto" },
{ETHERTYPE_DNA_DL, "DEC DNA Dump/Load" },
{ETHERTYPE_DNA_RC, "DEC DNA Remote Console" },
{ETHERTYPE_DNA_RT, "DEC DNA Routing" },
{ETHERTYPE_LAT, "DEC LAT" },
{ETHERTYPE_DEC_DIAG, "DEC Diagnostics" },
{ETHERTYPE_DEC_CUST, "DEC Customer use" },
{ETHERTYPE_DEC_SCA, "DEC LAVC/SCA" },
{ETHERTYPE_ETHBRIDGE, "Transparent Ethernet bridging" },
/*
* NDISWAN on Windows translates Ethernet frames from higher-level
* protocols into PPP frames to hand to the PPP driver, and translates
* PPP frames from the PPP driver to hand to the higher-level protocols.
*
* Apparently the PPP driver, on at least some versions of Windows,
* passes frames for internal-to-PPP protocols up through NDISWAN;
* the protocol type field appears to be passed through unchanged
* (unlike what's done with, for example, the protocol type field
* for IP, which is mapped from its PPP value to its Ethernet value).
*
* This means that we may see, on Ethernet captures, frames for
* protocols internal to PPP, so we list as "Ethernet" protocol
* types the PPP protocol types we've seen.
*/
{PPP_IPCP, "PPP IP Control Protocol" },
{PPP_LCP, "PPP Link Control Protocol" },
{PPP_PAP, "PPP Password Authentication Protocol" },
{PPP_CCP, "PPP Compression Control Protocol" },
{0, NULL } };
static void add_trailer(proto_tree *fh_tree, int trailer_id, tvbuff_t *tvb,
tvbuff_t *next_tvb, int offset_after_etype, guint length_before);
void
capture_ethertype(guint16 etype, int offset,
const u_char *pd, packet_counts *ld)
{
switch (etype) {
case ETHERTYPE_IP:
capture_ip(pd, offset, ld);
break;
case ETHERTYPE_IPX:
capture_ipx(pd, offset, ld);
break;
case ETHERTYPE_VLAN:
capture_vlan(pd, offset, ld);
break;
case ETHERTYPE_VINES:
capture_vines(pd, offset, ld);
break;
default:
ld->other++;
break;
}
}
void
ethertype(guint16 etype, tvbuff_t *tvb, int offset_after_etype,
packet_info *pinfo, proto_tree *tree, proto_tree *fh_tree,
int etype_id, int trailer_id)
{
char *description;
tvbuff_t *next_tvb;
guint length_before;
volatile gboolean dissector_found;
/* Add to proto_tree */
if (tree) {
proto_tree_add_uint(fh_tree, etype_id, tvb,
offset_after_etype - 2, 2, etype);
}
/* Tvbuff for the payload after the Ethernet type. */
next_tvb = tvb_new_subset(tvb, offset_after_etype, -1, -1);
pinfo->ethertype = etype;
/* Remember how much data there is in it. */
length_before = tvb_reported_length(next_tvb);
/* Look for sub-dissector, and call it if found.
Catch BoundsError and ReportedBoundsError, so that if the
reported length of "next_tvb" was reduced by some dissector
before an exception was thrown, we can still put in an item
for the trailer. */
TRY {
dissector_found = dissector_try_port(ethertype_dissector_table,
etype, next_tvb, pinfo, tree);
}
CATCH2(BoundsError, ReportedBoundsError) {
/* Well, somebody threw an exception; that means that a
dissector was found, so we don't need to dissect
the payload as data or update the protocol or info
columns. */
dissector_found = TRUE;
/* Add the trailer, if appropriate. */
add_trailer(fh_tree, trailer_id, tvb, next_tvb,
offset_after_etype, length_before);
/* Rrethrow the exception, so the "Short Frame" or "Mangled
Frame" indication can be put into the tree. */
RETHROW;
/* XXX - RETHROW shouldn't return. */
g_assert_not_reached();
}
ENDTRY;
if (!dissector_found) {
/* No sub-dissector found.
Label rest of packet as "Data" */
dissect_data(next_tvb, 0, pinfo, tree);
/* Label protocol */
switch (etype) {
case ETHERTYPE_LOOP:
if (check_col(pinfo->fd, COL_PROTOCOL)) {
col_add_fstr(pinfo->fd, COL_PROTOCOL, "LOOP");
}
break;
default:
if (check_col(pinfo->fd, COL_PROTOCOL)) {
col_add_fstr(pinfo->fd, COL_PROTOCOL, "0x%04x",
etype);
}
break;
}
if (check_col(pinfo->fd, COL_INFO)) {
description = match_strval(etype, etype_vals);
if (description) {
col_add_fstr(pinfo->fd, COL_INFO, "%s",
description);
}
}
}
add_trailer(fh_tree, trailer_id, tvb, next_tvb, offset_after_etype,
length_before);
}
static void
add_trailer(proto_tree *fh_tree, int trailer_id, tvbuff_t *tvb,
tvbuff_t *next_tvb, int offset_after_etype, guint length_before)
{
guint length;
tvbuff_t *volatile trailer_tvb;
if (fh_tree == NULL)
return; /* we're not building a protocol tree */
if (trailer_id == -1)
return; /* our caller doesn't care about trailers */
/* OK, how much is there in that tvbuff now? */
length = tvb_reported_length(next_tvb);
/* If there's less than there was before, what's left is
a trailer. */
if (length < length_before) {
/*
* Create a tvbuff for the padding.
*/
TRY {
trailer_tvb = tvb_new_subset(tvb,
offset_after_etype + length, -1, -1);
}
CATCH2(BoundsError, ReportedBoundsError) {
/* The packet doesn't have "length" bytes worth of
captured data left in it. No trailer to display. */
trailer_tvb = NULL;
}
ENDTRY;
} else
trailer_tvb = NULL; /* no trailer */
/* If there's some bytes left over, and we were given an item ID
for a trailer, mark those bytes as a trailer. */
if (trailer_tvb) {
guint trailer_length;
trailer_length = tvb_length(trailer_tvb);
if (trailer_length != 0) {
proto_tree_add_item(fh_tree, trailer_id, trailer_tvb, 0,
trailer_length, FALSE);
}
}
}
void
proto_register_ethertype(void)
{
/* subdissector code */
ethertype_dissector_table = register_dissector_table("ethertype");
}
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