diff options
Diffstat (limited to 'packet-ieee8023.c')
| -rw-r--r-- | packet-ieee8023.c | 134 |
1 files changed, 134 insertions, 0 deletions
diff --git a/packet-ieee8023.c b/packet-ieee8023.c new file mode 100644 index 0000000000..2a671860c4 --- /dev/null +++ b/packet-ieee8023.c @@ -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"); +} |