Pull a lot of common code for handling 802.3 frames (i.e., frames with a

length field rather than an Ethernet type field) into a
"dissect_802_3()" routine.

In that routine, catch exceptions thrown by the IPX or LLC dissector or
dissectors under them, so that the trailer information is added to the
tree even if an exception is thrown (similar to what "ethertype()"
does).

svn path=/trunk/; revision=3002
This commit is contained in:
Guy Harris 2001-02-08 07:08:05 +00:00
parent b1eb3635c2
commit 7f4a71ab8b
6 changed files with 206 additions and 147 deletions

View File

@ -1,7 +1,7 @@
# Makefile.am
# Automake file for Ethereal
#
# $Id: Makefile.am,v 1.281 2001/02/01 20:21:13 gram Exp $
# $Id: Makefile.am,v 1.282 2001/02/08 07:08:04 guy Exp $
#
# Ethereal - Network traffic analyzer
# By Gerald Combs <gerald@zing.org>
@ -121,6 +121,7 @@ DISSECTOR_SOURCES = \
packet-ipx.c \
packet-irc.c \
packet-ieee80211.c \
packet-ieee8023.c \
packet-isakmp.c\
packet-isis.c \
packet-isis-clv.c \
@ -249,6 +250,7 @@ noinst_HEADERS = \
packet-hclnfsd.h \
packet-http.h \
packet-ieee80211.h \
packet-ieee8023.h \
packet-ip.h \
packet-ipsec.h \
packet-ipv6.h \

View File

@ -1,7 +1,7 @@
## Makefile for building ethereal.exe with Microsoft C and nmake
## Use: nmake -f makefile.nmake
#
# $Id: Makefile.nmake,v 1.78 2001/02/02 04:03:37 gram Exp $
# $Id: Makefile.nmake,v 1.79 2001/02/08 07:08:05 guy Exp $
include config.nmake
@ -71,6 +71,7 @@ DISSECTOR_SOURCES = \
packet-ipx.c \
packet-irc.c \
packet-ieee80211.c \
packet-ieee8023.c \
packet-isakmp.c\
packet-isis.c \
packet-isis-clv.c \

View File

@ -1,7 +1,7 @@
/* packet-eth.c
* Routines for ethernet packet disassembly
*
* $Id: packet-eth.c,v 1.59 2001/01/21 22:10:22 guy Exp $
* $Id: packet-eth.c,v 1.60 2001/02/08 07:08:05 guy Exp $
*
* Ethereal - Network traffic analyzer
* By Gerald Combs <gerald@zing.org>
@ -36,6 +36,7 @@
#include "etypes.h"
#include "resolv.h"
#include "packet-eth.h"
#include "packet-ieee8023.h"
#include "packet-ipx.h"
#include "packet-isl.h"
#include "packet-llc.h"
@ -55,8 +56,6 @@ static gint ett_ieee8023 = -1;
static gint ett_ether2 = -1;
static dissector_handle_t isl_handle;
static dissector_handle_t ipx_handle;
static dissector_handle_t llc_handle;
#define ETH_HEADER_SIZE 14
@ -151,11 +150,9 @@ dissect_eth(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
const guint8 *pd;
guint16 etype;
volatile int ethhdr_type; /* the type of Ethernet frame */
volatile gboolean is_802_2;
int eth_offset;
volatile guint16 length;
tvbuff_t *volatile next_tvb;
tvbuff_t *volatile trailer_tvb;
proto_tree *volatile fh_tree = NULL;
tvb_compat(tvb, &pd, (int*)&eth_offset);
@ -178,24 +175,6 @@ dissect_eth(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
if (etype <= IEEE_802_3_MAX_LEN) {
length = etype;
/* Is there an 802.2 layer? I can tell by looking at the first 2
bytes after the 802.3 header. If they are 0xffff, then what
follows the 802.3 header is an IPX payload, meaning no 802.2.
(IPX/SPX is they only thing that can be contained inside a
straight 802.3 packet). A non-0xffff value means that there's an
802.2 layer inside the 802.3 layer */
ethhdr_type = ETHERNET_802_2;
TRY {
if (tvb_get_ntohs(tvb, 14) == 0xffff) {
ethhdr_type = ETHERNET_802_3;
}
}
CATCH2(BoundsError, ReportedBoundsError) {
; /* do nothing */
}
ENDTRY;
/* Oh, yuck. Cisco ISL frames require special interpretation of the
destination address field; fortunately, they can be recognized by
checking the first 5 octets of the destination address, which are
@ -209,13 +188,31 @@ dissect_eth(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
return;
}
/* Is there an 802.2 layer? I can tell by looking at the first 2
bytes after the 802.3 header. If they are 0xffff, then what
follows the 802.3 header is an IPX payload, meaning no 802.2.
(IPX/SPX is they only thing that can be contained inside a
straight 802.3 packet). A non-0xffff value means that there's an
802.2 layer inside the 802.3 layer */
is_802_2 = TRUE;
TRY {
if (tvb_get_ntohs(tvb, 14) == 0xffff) {
is_802_2 = FALSE;
}
}
CATCH2(BoundsError, ReportedBoundsError) {
; /* do nothing */
}
ENDTRY;
if (check_col(pinfo->fd, COL_INFO)) {
col_add_fstr(pinfo->fd, COL_INFO, "IEEE 802.3 %s",
(ethhdr_type == ETHERNET_802_3 ? "Raw " : ""));
(is_802_2 ? "" : "Raw "));
}
if (tree) {
ti = proto_tree_add_protocol_format(tree, proto_eth, tvb, 0, ETH_HEADER_SIZE,
"IEEE 802.3 %s", (ethhdr_type == ETHERNET_802_3 ? "Raw " : ""));
"IEEE 802.3 %s", (is_802_2 ? "" : "Raw "));
fh_tree = proto_item_add_subtree(ti, ett_ieee8023);
@ -225,8 +222,6 @@ dissect_eth(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
/* add items for eth.addr filter */
proto_tree_add_ether_hidden(fh_tree, hf_eth_addr, tvb, 0, 6, dst);
proto_tree_add_ether_hidden(fh_tree, hf_eth_addr, tvb, 6, 6, src);
proto_tree_add_uint(fh_tree, hf_eth_len, tvb, 12, 2, length);
}
/* Convert the LLC length from the 802.3 header to a total
@ -243,56 +238,9 @@ dissect_eth(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
if (pinfo->captured_len > length)
pinfo->captured_len = length;
/* Give the next dissector only 'length' number of bytes */
TRY {
next_tvb = tvb_new_subset(tvb, ETH_HEADER_SIZE, etype, etype);
trailer_tvb = tvb_new_subset(tvb, ETH_HEADER_SIZE + etype, -1, -1);
}
CATCH2(BoundsError, ReportedBoundsError) {
/* Either:
the packet doesn't have "etype" bytes worth of
captured data left in it - or it may not even have
"etype" bytes worth of data in it, period -
so the "tvb_new_subset()" creating "next_tvb"
threw an exception
or
the packet has exactly "etype" bytes worth of
captured data left in it, so the "tvb_new_subset()"
creating "trailer_tvb" threw an exception.
In either case, this means that all the data in the frame
is within the length value, so we give all the data to the
next protocol and have no trailer. */
next_tvb = tvb_new_subset(tvb, ETH_HEADER_SIZE, -1, etype);
trailer_tvb = NULL;
}
ENDTRY;
/* Dissect the payload either as IPX or as an LLC frame. */
switch (ethhdr_type) {
case ETHERNET_802_3:
call_dissector(ipx_handle, next_tvb, pinfo, tree);
break;
case ETHERNET_802_2:
call_dissector(llc_handle, next_tvb, pinfo, tree);
break;
}
/* If there's some bytes left over, mark them. */
if (trailer_tvb && tree) {
guint trailer_length;
trailer_length = tvb_length(trailer_tvb);
if (trailer_length != 0) {
proto_tree_add_item(fh_tree, hf_eth_trailer, trailer_tvb, 0,
trailer_length, FALSE);
}
}
dissect_802_3(etype, is_802_2, tvb, ETH_HEADER_SIZE, pinfo, tree, fh_tree,
hf_eth_len, hf_eth_trailer);
} else {
ethhdr_type = ETHERNET_II;
if (check_col(pinfo->fd, COL_INFO))
col_set_str(pinfo->fd, COL_INFO, "Ethernet II");
if (tree) {
@ -308,9 +256,6 @@ dissect_eth(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
proto_tree_add_ether_hidden(fh_tree, hf_eth_addr, tvb, 6, 6, src);
}
next_tvb = NULL; /* "ethertype()" will create the next tvb for us */
trailer_tvb = NULL; /* we don't know how big the trailer is */
ethertype(etype, tvb, ETH_HEADER_SIZE, pinfo, tree, fh_tree, hf_eth_type,
hf_eth_trailer);
}
@ -362,11 +307,9 @@ void
proto_reg_handoff_eth(void)
{
/*
* Get handles for the ISL, IPX, and LLC dissectors.
* Get a handle for the ISL dissector.
*/
isl_handle = find_dissector("isl");
ipx_handle = find_dissector("ipx");
llc_handle = find_dissector("llc");
dissector_add("wtap_encap", WTAP_ENCAP_ETHERNET, dissect_eth,
proto_eth);

134
packet-ieee8023.c Normal file
View File

@ -0,0 +1,134 @@
/* packet-ieee8023.c
* Routine for dissecting 802.3 (as opposed to D/I/X Ethernet) packets.
*
* $Id: packet-ieee8023.c,v 1.1 2001/02/08 07:08:05 guy Exp $
*
* 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-ieee8023.h"
static dissector_handle_t ipx_handle;
static dissector_handle_t llc_handle;
static void add_trailer(proto_tree *fh_tree, int trailer_id,
tvbuff_t *trailer_tvb);
void
dissect_802_3(int length, gboolean is_802_2, tvbuff_t *tvb,
int offset_after_length, packet_info *pinfo, proto_tree *tree,
proto_tree *fh_tree, int length_id, int trailer_id)
{
tvbuff_t *volatile next_tvb;
tvbuff_t *volatile trailer_tvb;
if (fh_tree)
proto_tree_add_uint(fh_tree, length_id, tvb, offset_after_length - 2, 2,
length);
/* Give the next dissector only 'length' number of bytes */
TRY {
next_tvb = tvb_new_subset(tvb, offset_after_length, length, length);
trailer_tvb = tvb_new_subset(tvb, offset_after_length + length, -1, -1);
}
CATCH2(BoundsError, ReportedBoundsError) {
/* Either:
the packet doesn't have "length" bytes worth of
captured data left in it - or it may not even have
"length" bytes worth of data in it, period -
so the "tvb_new_subset()" creating "next_tvb"
threw an exception
or
the packet has exactly "length" bytes worth of
captured data left in it, so the "tvb_new_subset()"
creating "trailer_tvb" threw an exception.
In either case, this means that all the data in the frame
is within the length value, so we give all the data to the
next protocol and have no trailer. */
next_tvb = tvb_new_subset(tvb, offset_after_length, -1, length);
trailer_tvb = NULL;
}
ENDTRY;
/* Dissect the payload either as IPX or as an LLC frame.
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 {
if (is_802_2)
call_dissector(llc_handle, next_tvb, pinfo, tree);
else
call_dissector(ipx_handle, next_tvb, pinfo, tree);
}
CATCH2(BoundsError, ReportedBoundsError) {
/* Well, somebody threw an exception. Add the trailer, if appropriate. */
add_trailer(fh_tree, trailer_id, trailer_tvb);
/* Rethrow 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;
add_trailer(fh_tree, trailer_id, trailer_tvb);
}
static void
add_trailer(proto_tree *fh_tree, int trailer_id, tvbuff_t *trailer_tvb)
{
/* If there's some bytes left over, mark them. */
if (trailer_tvb && fh_tree) {
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_reg_handoff_ieee802_3(void)
{
/*
* Get handles for the IPX and LLC dissectors.
*/
ipx_handle = find_dissector("ipx");
llc_handle = find_dissector("llc");
}

34
packet-ieee8023.h Normal file
View File

@ -0,0 +1,34 @@
/* packet-ieee8023.h
* Declaration of routine for dissecting 802.3 (as opposed to D/I/X Ethernet)
* packets.
*
* $Id: packet-ieee8023.h,v 1.1 2001/02/08 07:08:05 guy Exp $
*
* 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.
*/
#ifndef __PACKET_IEEE8023_H__
#define __PACKET_IEEE8023_H__
void dissect_802_3(int length, gboolean is_802_2, tvbuff_t *tvb,
int offset_after_length, packet_info *pinfo, proto_tree *tree,
proto_tree *fh_tree, int length_id, int trailer_id);
#endif

View File

@ -1,7 +1,7 @@
/* packet-vlan.c
* Routines for VLAN 802.1Q ethernet header disassembly
*
* $Id: packet-vlan.c,v 1.32 2001/02/05 02:47:31 guy Exp $
* $Id: packet-vlan.c,v 1.33 2001/02/08 07:08:05 guy Exp $
*
* Ethereal - Network traffic analyzer
* By Gerald Combs <gerald@zing.org>
@ -37,6 +37,7 @@
#include <glib.h>
#include "packet.h"
#include "packet-ieee8023.h"
#include "packet-ipx.h"
#include "packet-llc.h"
#include "etypes.h"
@ -51,9 +52,6 @@ static int hf_vlan_trailer = -1;
static gint ett_vlan = -1;
static dissector_handle_t ipx_handle;
static dissector_handle_t llc_handle;
void
capture_vlan(const u_char *pd, int offset, packet_counts *ld ) {
guint16 encap_proto;
@ -79,8 +77,6 @@ dissect_vlan(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
proto_tree *ti;
guint16 tci,encap_proto;
volatile gboolean is_802_2;
tvbuff_t *volatile next_tvb;
tvbuff_t *volatile trailer_tvb;
proto_tree *volatile vlan_tree;
if (check_col(pinfo->fd, COL_PROTOCOL))
@ -106,37 +102,8 @@ dissect_vlan(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
proto_tree_add_uint(vlan_tree, hf_vlan_id, tvb, 0, 2, tci);
}
encap_proto = tvb_get_ntohs( tvb, 2 );
if ( encap_proto <= IEEE_802_3_MAX_LEN) {
/* Give the next dissector only 'encap_proto' number of bytes */
proto_tree_add_uint(vlan_tree, hf_vlan_len, tvb, 2, 2, encap_proto);
TRY {
next_tvb = tvb_new_subset(tvb, 4, encap_proto, encap_proto);
trailer_tvb = tvb_new_subset(tvb, 4 + encap_proto, -1, -1);
}
CATCH2(BoundsError, ReportedBoundsError) {
/* Either:
the packet doesn't have "encap_proto" bytes worth of
captured data left in it - or it may not even have
"encap_proto" bytes worth of data in it, period -
so the "tvb_new_subset()" creating "next_tvb"
threw an exception
or
the packet has exactly "encap_proto" bytes worth of
captured data left in it, so the "tvb_new_subset()"
creating "trailer_tvb" threw an exception.
In either case, this means that all the data in the frame
is within the length value, so we give all the data to the
next protocol and have no trailer. */
next_tvb = tvb_new_subset(tvb, 4, -1, encap_proto);
trailer_tvb = NULL;
}
ENDTRY;
encap_proto = tvb_get_ntohs(tvb, 2);
if (encap_proto <= IEEE_802_3_MAX_LEN) {
/* Is there an 802.2 layer? I can tell by looking at the first 2
bytes after the VLAN header. If they are 0xffff, then what
follows the VLAN header is an IPX payload, meaning no 802.2.
@ -146,7 +113,7 @@ dissect_vlan(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
802.2 layer inside the VLAN layer */
is_802_2 = TRUE;
TRY {
if (tvb_get_ntohs(next_tvb, 2) == 0xffff) {
if (tvb_get_ntohs(tvb, 4) == 0xffff) {
is_802_2 = FALSE;
}
}
@ -155,25 +122,9 @@ dissect_vlan(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
}
ENDTRY;
if (is_802_2 ) {
/* 802.2 LLC */
call_dissector(llc_handle, next_tvb, pinfo, tree);
} else {
call_dissector(ipx_handle, next_tvb, pinfo, tree);
}
/* If there's some bytes left over, mark them. */
if (trailer_tvb && tree) {
int trailer_length;
const guint8 *ptr;
trailer_length = tvb_length(trailer_tvb);
if (trailer_length > 0) {
ptr = tvb_get_ptr(trailer_tvb, 0, trailer_length);
proto_tree_add_bytes(vlan_tree, hf_vlan_trailer, trailer_tvb, 0,
trailer_length, ptr);
}
}
dissect_802_3(encap_proto, is_802_2, tvb, 4, pinfo, tree, vlan_tree,
hf_vlan_len, hf_vlan_trailer);
} else {
ethertype(encap_proto, tvb, 4, pinfo, tree, vlan_tree,
hf_vlan_etype, hf_vlan_trailer);
@ -215,11 +166,5 @@ proto_register_vlan(void)
void
proto_reg_handoff_vlan(void)
{
/*
* Get handles for the IPX and LLC dissectors.
*/
llc_handle = find_dissector("llc");
ipx_handle = find_dissector("ipx");
dissector_add("ethertype", ETHERTYPE_VLAN, dissect_vlan, proto_vlan);
}