forked from osmocom/wireshark
![Gilbert Ramirez](/assets/img/avatar_default.png)
Also move ncp222.py, x11-fields, process-x11-fields.pl, make-reg-dotc, and make-reg-dotc.py. Adjust #include lines in files that include packet-*.h files. svn path=/trunk/; revision=11410
472 lines
16 KiB
C
472 lines
16 KiB
C
/* packet-eth.c
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* Routines for ethernet packet disassembly
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*
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* $Id$
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*
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* Ethereal - Network traffic analyzer
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* By Gerald Combs <gerald@ethereal.com>
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* Copyright 1998 Gerald Combs
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version 2
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* of the License, or (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
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*/
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#ifdef HAVE_CONFIG_H
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# include "config.h"
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#endif
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#include <glib.h>
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#include <epan/packet.h>
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#include "prefs.h"
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#include "etypes.h"
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#include <epan/resolv.h>
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#include "packet-eth.h"
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#include "packet-ieee8023.h"
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#include "packet-ipx.h"
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#include "packet-isl.h"
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#include "packet-llc.h"
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#include "crc32.h"
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#include "tap.h"
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/* Interpret capture file as FW1 monitor file */
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static gboolean eth_interpret_as_fw1_monitor = FALSE;
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/* protocols and header fields */
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static int proto_eth = -1;
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static int hf_eth_dst = -1;
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static int hf_eth_src = -1;
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static int hf_eth_len = -1;
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static int hf_eth_type = -1;
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static int hf_eth_addr = -1;
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static int hf_eth_trailer = -1;
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static gint ett_ieee8023 = -1;
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static gint ett_ether2 = -1;
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static dissector_handle_t isl_handle;
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static dissector_handle_t fw1_handle;
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static heur_dissector_list_t heur_subdissector_list;
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static int eth_tap = -1;
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#define ETH_HEADER_SIZE 14
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/* These are the Netware-ish names for the different Ethernet frame types.
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EthernetII: The ethernet with a Type field instead of a length field
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Ethernet802.2: An 802.3 header followed by an 802.2 header
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Ethernet802.3: A raw 802.3 packet. IPX/SPX can be the only payload.
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There's no 802.2 hdr in this.
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EthernetSNAP: Basically 802.2, just with 802.2SNAP. For our purposes,
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there's no difference between 802.2 and 802.2SNAP, since we just
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pass it down to the LLC dissector. -- Gilbert
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*/
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#define ETHERNET_II 0
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#define ETHERNET_802_2 1
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#define ETHERNET_802_3 2
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#define ETHERNET_SNAP 3
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void
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capture_eth(const guchar *pd, int offset, int len, packet_counts *ld)
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{
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guint16 etype, length;
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int ethhdr_type; /* the type of ethernet frame */
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if (!BYTES_ARE_IN_FRAME(offset, len, ETH_HEADER_SIZE)) {
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ld->other++;
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return;
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}
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etype = pntohs(&pd[offset+12]);
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/*
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* If the type/length field is <= the maximum 802.3 length,
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* and is not zero, this is an 802.3 frame, and it's a length
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* field; it might be an Novell "raw 802.3" frame, with no
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* 802.2 LLC header, or it might be a frame with an 802.2 LLC
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* header.
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*
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* If the type/length field is > the maximum 802.3 length,
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* this is an Ethernet II frame, and it's a type field.
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*
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* If the type/length field is zero (ETHERTYPE_UNK), this is
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* a frame used internally by the Cisco MDS switch to contain
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* Fibre Channel ("Vegas"). We treat that as an Ethernet II
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* frame; the dissector for those frames registers itself with
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* an ethernet type of ETHERTYPE_UNK.
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*/
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if (etype <= IEEE_802_3_MAX_LEN && etype != ETHERTYPE_UNK) {
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length = etype;
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/* Is there an 802.2 layer? I can tell by looking at the first 2
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bytes after the 802.3 header. If they are 0xffff, then what
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follows the 802.3 header is an IPX payload, meaning no 802.2.
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(IPX/SPX is they only thing that can be contained inside a
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straight 802.3 packet). A non-0xffff value means that there's an
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802.2 layer inside the 802.3 layer */
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if (pd[offset+14] == 0xff && pd[offset+15] == 0xff) {
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ethhdr_type = ETHERNET_802_3;
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}
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else {
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ethhdr_type = ETHERNET_802_2;
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}
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/* Oh, yuck. Cisco ISL frames require special interpretation of the
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destination address field; fortunately, they can be recognized by
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checking the first 5 octets of the destination address, which are
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01-00-0C-00-00 for ISL frames. */
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if (pd[offset] == 0x01 && pd[offset+1] == 0x00 && pd[offset+2] == 0x0C
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&& pd[offset+3] == 0x00 && pd[offset+4] == 0x00) {
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capture_isl(pd, offset, len, ld);
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return;
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}
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/* Convert the LLC length from the 802.3 header to a total
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frame length, by adding in the size of any data that preceded
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the Ethernet header, and adding in the Ethernet header size,
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and set the payload and captured-payload lengths to the minima
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of the total length and the frame lengths. */
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length += offset + ETH_HEADER_SIZE;
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if (len > length)
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len = length;
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} else {
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ethhdr_type = ETHERNET_II;
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}
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offset += ETH_HEADER_SIZE;
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switch (ethhdr_type) {
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case ETHERNET_802_3:
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capture_ipx(ld);
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break;
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case ETHERNET_802_2:
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capture_llc(pd, offset, len, ld);
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break;
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case ETHERNET_II:
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capture_ethertype(etype, pd, offset, len, ld);
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break;
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}
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}
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static void
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dissect_eth_common(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree,
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int fcs_len)
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{
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proto_item *ti;
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eth_hdr *ehdr;
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volatile gboolean is_802_2;
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proto_tree *volatile fh_tree = NULL;
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const char *src_addr, *dst_addr;
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static eth_hdr ehdrs[4];
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static int ehdr_num=0;
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ehdr_num++;
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if(ehdr_num>=4){
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ehdr_num=0;
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}
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ehdr=&ehdrs[ehdr_num];
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if (check_col(pinfo->cinfo, COL_PROTOCOL))
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col_set_str(pinfo->cinfo, COL_PROTOCOL, "Ethernet");
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src_addr=tvb_get_ptr(tvb, 6, 6);
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SET_ADDRESS(&pinfo->dl_src, AT_ETHER, 6, src_addr);
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SET_ADDRESS(&pinfo->src, AT_ETHER, 6, src_addr);
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SET_ADDRESS(&ehdr->src, AT_ETHER, 6, src_addr);
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dst_addr=tvb_get_ptr(tvb, 0, 6);
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SET_ADDRESS(&pinfo->dl_dst, AT_ETHER, 6, dst_addr);
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SET_ADDRESS(&pinfo->dst, AT_ETHER, 6, dst_addr);
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SET_ADDRESS(&ehdr->dst, AT_ETHER, 6, dst_addr);
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ehdr->type = tvb_get_ntohs(tvb, 12);
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/*
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* In case the packet is a non-Ethernet packet inside
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* Ethernet framing, allow heuristic dissectors to take
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* a first look before we assume that it's actually an
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* Ethernet packet.
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*/
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if (dissector_try_heuristic(heur_subdissector_list, tvb, pinfo, tree))
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goto end_of_eth;
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/*
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* If the type/length field is <= the maximum 802.3 length,
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* and is not zero, this is an 802.3 frame, and it's a length
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* field; it might be an Novell "raw 802.3" frame, with no
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* 802.2 LLC header, or it might be a frame with an 802.2 LLC
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* header.
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*
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* If the type/length field is > the maximum 802.3 length,
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* this is an Ethernet II frame, and it's a type field.
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*
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* If the type/length field is zero (ETHERTYPE_UNK), this is
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* a frame used internally by the Cisco MDS switch to contain
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* Fibre Channel ("Vegas"). We treat that as an Ethernet II
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* frame; the dissector for those frames registers itself with
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* an ethernet type of ETHERTYPE_UNK.
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*/
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if (ehdr->type <= IEEE_802_3_MAX_LEN && ehdr->type != ETHERTYPE_UNK) {
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/* Oh, yuck. Cisco ISL frames require special interpretation of the
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destination address field; fortunately, they can be recognized by
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checking the first 5 octets of the destination address, which are
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01-00-0C-00-00 for ISL frames. */
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if ( tvb_get_guint8(tvb, 0) == 0x01 &&
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tvb_get_guint8(tvb, 1) == 0x00 &&
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tvb_get_guint8(tvb, 2) == 0x0C &&
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tvb_get_guint8(tvb, 3) == 0x00 &&
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tvb_get_guint8(tvb, 4) == 0x00 ) {
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call_dissector(isl_handle, tvb, pinfo, tree);
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goto end_of_eth;
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}
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/* Is there an 802.2 layer? I can tell by looking at the first 2
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bytes after the 802.3 header. If they are 0xffff, then what
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follows the 802.3 header is an IPX payload, meaning no 802.2.
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(IPX/SPX is they only thing that can be contained inside a
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straight 802.3 packet). A non-0xffff value means that there's an
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802.2 layer inside the 802.3 layer */
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is_802_2 = TRUE;
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TRY {
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if (tvb_get_ntohs(tvb, 14) == 0xffff) {
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is_802_2 = FALSE;
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}
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}
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CATCH2(BoundsError, ReportedBoundsError) {
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; /* do nothing */
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}
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ENDTRY;
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if (check_col(pinfo->cinfo, COL_INFO)) {
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col_add_fstr(pinfo->cinfo, COL_INFO, "IEEE 802.3 Ethernet %s",
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(is_802_2 ? "" : "Raw "));
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}
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if (tree) {
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ti = proto_tree_add_protocol_format(tree, proto_eth, tvb, 0, ETH_HEADER_SIZE,
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"IEEE 802.3 Ethernet %s", (is_802_2 ? "" : "Raw "));
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fh_tree = proto_item_add_subtree(ti, ett_ieee8023);
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}
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proto_tree_add_ether(fh_tree, hf_eth_dst, tvb, 0, 6, dst_addr);
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proto_tree_add_ether(fh_tree, hf_eth_src, tvb, 6, 6, src_addr);
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/* add items for eth.addr filter */
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proto_tree_add_ether_hidden(fh_tree, hf_eth_addr, tvb, 0, 6, dst_addr);
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proto_tree_add_ether_hidden(fh_tree, hf_eth_addr, tvb, 6, 6, src_addr);
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dissect_802_3(ehdr->type, is_802_2, tvb, ETH_HEADER_SIZE, pinfo, tree, fh_tree,
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hf_eth_len, hf_eth_trailer, fcs_len);
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} else {
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if (eth_interpret_as_fw1_monitor) {
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call_dissector(fw1_handle, tvb, pinfo, tree);
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goto end_of_eth;
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}
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if (check_col(pinfo->cinfo, COL_INFO))
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col_set_str(pinfo->cinfo, COL_INFO, "Ethernet II");
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if (tree) {
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ti = proto_tree_add_protocol_format(tree, proto_eth, tvb, 0, ETH_HEADER_SIZE,
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"Ethernet II, Src: %s, Dst: %s",
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ether_to_str(src_addr), ether_to_str(dst_addr));
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fh_tree = proto_item_add_subtree(ti, ett_ether2);
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}
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proto_tree_add_ether(fh_tree, hf_eth_dst, tvb, 0, 6, dst_addr);
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proto_tree_add_ether(fh_tree, hf_eth_src, tvb, 6, 6, src_addr);
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/* add items for eth.addr filter */
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proto_tree_add_ether_hidden(fh_tree, hf_eth_addr, tvb, 0, 6, dst_addr);
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proto_tree_add_ether_hidden(fh_tree, hf_eth_addr, tvb, 6, 6, src_addr);
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ethertype(ehdr->type, tvb, ETH_HEADER_SIZE, pinfo, tree, fh_tree, hf_eth_type,
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hf_eth_trailer, fcs_len);
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}
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end_of_eth:
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tap_queue_packet(eth_tap, pinfo, ehdr);
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return;
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}
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/*
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* Add an Ethernet trailer - which, for some captures, might be the FCS
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* rather than a pad-to-60-bytes trailer.
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*
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* If fcs_len is 0, we assume the frame has no FCS; if it's 4, we assume
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* it has an FCS; if it's anything else (such as -1, which means "maybe
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* it does, maybe it doesn't"), we try to infer whether it has an FCS.
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*/
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void
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add_ethernet_trailer(proto_tree *fh_tree, int trailer_id, tvbuff_t *tvb,
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tvbuff_t *trailer_tvb, int fcs_len)
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{
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/* If there're some bytes left over, show those bytes as a trailer.
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However, if the Ethernet frame was claimed to have had 64 or more
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bytes - i.e., it was at least an FCS worth of data longer than
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the minimum payload size - assume the last 4 bytes of the trailer
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are an FCS. */
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if (trailer_tvb && fh_tree) {
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guint trailer_length, trailer_reported_length;
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gboolean has_fcs = FALSE;
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trailer_length = tvb_length(trailer_tvb);
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trailer_reported_length = tvb_reported_length(trailer_tvb);
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if (fcs_len != 0) {
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/* If fcs_len is 4, we assume we definitely have an FCS.
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Otherwise, then, if the frame is big enough that, if we
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have a trailer, it probably inclues an FCS, and we have
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enough space in the trailer for the FCS, we assume we
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have an FCS.
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"Big enough" means 64 bytes or more; any frame that big
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needs no trailer, as there's no need to pad an Ethernet
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packet past 60 bytes.
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The trailer must be at least 4 bytes long to have enough
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space for an FCS. */
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if (fcs_len == 4 || (tvb_reported_length(tvb) >= 64 &&
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trailer_reported_length >= 4)) {
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/* Either we know we have an FCS, or we believe we have an FCS. */
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if (trailer_length < trailer_reported_length) {
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/* The packet is claimed to have enough data for a 4-byte FCS,
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but we didn't capture all of the packet.
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Slice off the 4-byte FCS from the reported length, and
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trim the captured length so it's no more than the reported
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length; that will slice off what of the FCS, if any, is
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in the captured packet. */
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trailer_reported_length -= 4;
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if (trailer_length > trailer_reported_length)
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trailer_length = trailer_reported_length;
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has_fcs = TRUE;
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} else {
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/* We captured all of the packet, including what appears to
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be a 4-byte FCS. Slice it off. */
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trailer_length -= 4;
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trailer_reported_length -= 4;
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has_fcs = TRUE;
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}
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}
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}
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if (trailer_length != 0) {
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proto_tree_add_item(fh_tree, trailer_id, trailer_tvb, 0,
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trailer_length, FALSE);
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}
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if (has_fcs) {
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guint32 sent_fcs = tvb_get_ntohl(trailer_tvb, trailer_length);
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guint32 fcs = crc32_802_tvb(tvb, tvb_length(tvb) - 4);
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if (fcs == sent_fcs) {
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proto_tree_add_text(fh_tree, trailer_tvb, trailer_length, 4,
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"Frame check sequence: 0x%08x (correct)",
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sent_fcs);
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} else {
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proto_tree_add_text(fh_tree, trailer_tvb, trailer_length, 4,
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"Frame check sequence: 0x%08x (incorrect, should be 0x%08x)",
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sent_fcs, fcs);
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}
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}
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}
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}
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/* Called for the Ethernet Wiretap encapsulation type; pass the FCS length
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reported to us. */
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static void
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dissect_eth_maybefcs(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
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{
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dissect_eth_common(tvb, pinfo, tree, pinfo->pseudo_header->eth.fcs_len);
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}
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/* Called by other dissectors - for now, we assume Ethernet encapsulated
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inside other protocols doesn't include the FCS. */
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static void
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dissect_eth(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
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{
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dissect_eth_common(tvb, pinfo, tree, 0);
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}
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void
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proto_register_eth(void)
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{
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static hf_register_info hf[] = {
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{ &hf_eth_dst,
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{ "Destination", "eth.dst", FT_ETHER, BASE_NONE, NULL, 0x0,
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"Destination Hardware Address", HFILL }},
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{ &hf_eth_src,
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{ "Source", "eth.src", FT_ETHER, BASE_NONE, NULL, 0x0,
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"Source Hardware Address", HFILL }},
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{ &hf_eth_len,
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{ "Length", "eth.len", FT_UINT16, BASE_DEC, NULL, 0x0,
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"", HFILL }},
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/* registered here but handled in ethertype.c */
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{ &hf_eth_type,
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{ "Type", "eth.type", FT_UINT16, BASE_HEX, VALS(etype_vals), 0x0,
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"", HFILL }},
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{ &hf_eth_addr,
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{ "Source or Destination Address", "eth.addr", FT_ETHER, BASE_NONE, NULL, 0x0,
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"Source or Destination Hardware Address", HFILL }},
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{ &hf_eth_trailer,
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{ "Trailer", "eth.trailer", FT_BYTES, BASE_NONE, NULL, 0x0,
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"Ethernet Trailer or Checksum", HFILL }},
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};
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static gint *ett[] = {
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&ett_ieee8023,
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&ett_ether2,
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};
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module_t *eth_module;
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proto_eth = proto_register_protocol("Ethernet", "Ethernet", "eth");
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proto_register_field_array(proto_eth, hf, array_length(hf));
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proto_register_subtree_array(ett, array_length(ett));
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/* subdissector code */
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register_heur_dissector_list("eth", &heur_subdissector_list);
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/* Register configuration preferences */
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eth_module = prefs_register_protocol(proto_eth, NULL);
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prefs_register_bool_preference(eth_module, "interpret_as_fw1_monitor",
|
|
"Interpret as FireWall-1 monitor file",
|
|
"Whether the capture file should be interpreted as a CheckPoint FireWall-1 monitor file",
|
|
ð_interpret_as_fw1_monitor);
|
|
|
|
register_dissector("eth", dissect_eth, proto_eth);
|
|
eth_tap = register_tap("eth");
|
|
}
|
|
|
|
void
|
|
proto_reg_handoff_eth(void)
|
|
{
|
|
dissector_handle_t eth_handle, eth_maybefcs_handle;
|
|
|
|
/*
|
|
* Get a handle for the ISL dissector.
|
|
*/
|
|
isl_handle = find_dissector("isl");
|
|
fw1_handle = find_dissector("fw1");
|
|
|
|
eth_maybefcs_handle = create_dissector_handle(dissect_eth_maybefcs,
|
|
proto_eth);
|
|
dissector_add("wtap_encap", WTAP_ENCAP_ETHERNET, eth_maybefcs_handle);
|
|
|
|
eth_handle = find_dissector("eth");
|
|
dissector_add("ethertype", ETHERTYPE_ETHBRIDGE, eth_handle);
|
|
dissector_add("chdlctype", ETHERTYPE_ETHBRIDGE, eth_handle);
|
|
dissector_add("gre.proto", ETHERTYPE_ETHBRIDGE, eth_handle);
|
|
}
|