/* packet-eth.c
* Routines for ethernet packet disassembly
*
- * $Id: packet-eth.c,v 1.74 2002/08/02 23:35:49 jmayer Exp $
+ * $Id: packet-eth.c,v 1.88 2003/10/01 07:11:44 guy Exp $
*
* Ethereal - Network traffic analyzer
* By Gerald Combs <gerald@ethereal.com>
* 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.
#include <glib.h>
#include <epan/packet.h>
+#include "prefs.h"
#include "etypes.h"
#include <epan/resolv.h>
#include "packet-eth.h"
#include "packet-ipx.h"
#include "packet-isl.h"
#include "packet-llc.h"
+#include "crc32.h"
+#include "tap.h"
+
+/* Interpret capture file as FW1 monitor file */
+static gboolean eth_interpret_as_fw1_monitor = FALSE;
/* protocols and header fields */
static int proto_eth = -1;
static gint ett_ether2 = -1;
static dissector_handle_t isl_handle;
+static dissector_handle_t fw1_handle;
+
+static int eth_tap = -1;
#define ETH_HEADER_SIZE 14
ld->other++;
return;
}
-
+
etype = pntohs(&pd[offset+12]);
- /* either ethernet802.3 or ethernet802.2 */
- if (etype <= IEEE_802_3_MAX_LEN) {
+ /*
+ * If the type/length field is <= the maximum 802.3 length,
+ * and is not zero, this is an 802.3 frame, and it's a length
+ * field; it might be an Novell "raw 802.3" frame, with no
+ * 802.2 LLC header, or it might be a frame with an 802.2 LLC
+ * header.
+ *
+ * If the type/length field is > the maximum 802.3 length,
+ * this is an Ethernet II frame, and it's a type field.
+ *
+ * If the type/length field is zero (ETHERTYPE_UNK), this is
+ * a frame used internally by the Cisco MDS switch to contain
+ * Fibre Channel ("Vegas"). We treat that as an Ethernet II
+ * frame; the dissector for those frames registers itself with
+ * an ethernet type of ETHERTYPE_UNK.
+ */
+ if (etype <= IEEE_802_3_MAX_LEN && etype != ETHERTYPE_UNK) {
length = etype;
/* Is there an 802.2 layer? I can tell by looking at the first 2
}
static void
-dissect_eth(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
+dissect_eth_common(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree,
+ int fcs_len)
{
proto_item *ti;
- const guint8 *dst, *src;
-
- guint16 etype;
+ eth_hdr *ehdr;
volatile gboolean is_802_2;
proto_tree *volatile fh_tree = NULL;
+ const char *src_addr, *dst_addr;
+ static eth_hdr ehdrs[4];
+ static int ehdr_num=0;
- if (check_col(pinfo->cinfo, COL_PROTOCOL))
- col_set_str(pinfo->cinfo, COL_PROTOCOL, "Ethernet");
+ ehdr_num++;
+ if(ehdr_num>=4){
+ ehdr_num=0;
+ }
+ ehdr=&ehdrs[ehdr_num];
- src = tvb_get_ptr(tvb, 6, 6);
- dst = tvb_get_ptr(tvb, 0, 6);
- SET_ADDRESS(&pinfo->dl_src, AT_ETHER, 6, src);
- SET_ADDRESS(&pinfo->src, AT_ETHER, 6, src);
- SET_ADDRESS(&pinfo->dl_dst, AT_ETHER, 6, dst);
- SET_ADDRESS(&pinfo->dst, AT_ETHER, 6, dst);
- etype = tvb_get_ntohs(tvb, 12);
+ if (check_col(pinfo->cinfo, COL_PROTOCOL))
+ col_set_str(pinfo->cinfo, COL_PROTOCOL, "Ethernet");
- /* either ethernet802.3 or ethernet802.2 */
- if (etype <= IEEE_802_3_MAX_LEN) {
+ src_addr=tvb_get_ptr(tvb, 6, 6);
+ SET_ADDRESS(&pinfo->dl_src, AT_ETHER, 6, src_addr);
+ SET_ADDRESS(&pinfo->src, AT_ETHER, 6, src_addr);
+ SET_ADDRESS(&ehdr->src, AT_ETHER, 6, src_addr);
+ dst_addr=tvb_get_ptr(tvb, 0, 6);
+ SET_ADDRESS(&pinfo->dl_dst, AT_ETHER, 6, dst_addr);
+ SET_ADDRESS(&pinfo->dst, AT_ETHER, 6, dst_addr);
+ SET_ADDRESS(&ehdr->dst, AT_ETHER, 6, dst_addr);
+
+ ehdr->type = tvb_get_ntohs(tvb, 12);
+
+ /*
+ * If the type/length field is <= the maximum 802.3 length,
+ * and is not zero, this is an 802.3 frame, and it's a length
+ * field; it might be an Novell "raw 802.3" frame, with no
+ * 802.2 LLC header, or it might be a frame with an 802.2 LLC
+ * header.
+ *
+ * If the type/length field is > the maximum 802.3 length,
+ * this is an Ethernet II frame, and it's a type field.
+ *
+ * If the type/length field is zero (ETHERTYPE_UNK), this is
+ * a frame used internally by the Cisco MDS switch to contain
+ * Fibre Channel ("Vegas"). We treat that as an Ethernet II
+ * frame; the dissector for those frames registers itself with
+ * an ethernet type of ETHERTYPE_UNK.
+ */
+ if (ehdr->type <= IEEE_802_3_MAX_LEN && ehdr->type != ETHERTYPE_UNK) {
/* 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
tvb_get_guint8(tvb, 3) == 0x00 &&
tvb_get_guint8(tvb, 4) == 0x00 ) {
call_dissector(isl_handle, tvb, pinfo, tree);
- return;
+ goto end_of_eth;
}
/* Is there an 802.2 layer? I can tell by looking at the first 2
"IEEE 802.3 Ethernet %s", (is_802_2 ? "" : "Raw "));
fh_tree = proto_item_add_subtree(ti, ett_ieee8023);
+ }
- proto_tree_add_ether(fh_tree, hf_eth_dst, tvb, 0, 6, dst);
- proto_tree_add_ether(fh_tree, hf_eth_src, tvb, 6, 6, src);
+ proto_tree_add_ether(fh_tree, hf_eth_dst, tvb, 0, 6, dst_addr);
+ proto_tree_add_ether(fh_tree, hf_eth_src, tvb, 6, 6, src_addr);
/* 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_ether_hidden(fh_tree, hf_eth_addr, tvb, 0, 6, dst_addr);
+ proto_tree_add_ether_hidden(fh_tree, hf_eth_addr, tvb, 6, 6, src_addr);
- dissect_802_3(etype, is_802_2, tvb, ETH_HEADER_SIZE, pinfo, tree, fh_tree,
- hf_eth_len, hf_eth_trailer);
+ dissect_802_3(ehdr->type, is_802_2, tvb, ETH_HEADER_SIZE, pinfo, tree, fh_tree,
+ hf_eth_len, hf_eth_trailer, fcs_len);
} else {
+ if (eth_interpret_as_fw1_monitor) {
+ call_dissector(fw1_handle, tvb, pinfo, tree);
+ goto end_of_eth;
+ }
+
if (check_col(pinfo->cinfo, COL_INFO))
col_set_str(pinfo->cinfo, COL_INFO, "Ethernet II");
if (tree) {
ti = proto_tree_add_protocol_format(tree, proto_eth, tvb, 0, ETH_HEADER_SIZE,
- "Ethernet II");
+ "Ethernet II, Src: %s, Dst: %s",
+ ether_to_str(src_addr), ether_to_str(dst_addr));
fh_tree = proto_item_add_subtree(ti, ett_ether2);
+ }
- proto_tree_add_ether(fh_tree, hf_eth_dst, tvb, 0, 6, dst);
- proto_tree_add_ether(fh_tree, hf_eth_src, tvb, 6, 6, src);
+ proto_tree_add_ether(fh_tree, hf_eth_dst, tvb, 0, 6, dst_addr);
+ proto_tree_add_ether(fh_tree, hf_eth_src, tvb, 6, 6, src_addr);
/* 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_ether_hidden(fh_tree, hf_eth_addr, tvb, 0, 6, dst_addr);
+ proto_tree_add_ether_hidden(fh_tree, hf_eth_addr, tvb, 6, 6, src_addr);
+
+ ethertype(ehdr->type, tvb, ETH_HEADER_SIZE, pinfo, tree, fh_tree, hf_eth_type,
+ hf_eth_trailer, fcs_len);
+ }
+
+end_of_eth:
+ tap_queue_packet(eth_tap, pinfo, ehdr);
+ return;
+}
- ethertype(etype, tvb, ETH_HEADER_SIZE, pinfo, tree, fh_tree, hf_eth_type,
- hf_eth_trailer);
+/*
+ * Add an Ethernet trailer - which, for some captures, might be the FCS
+ * rather than a pad-to-60-bytes trailer.
+ *
+ * If fcs_len is 0, we assume the frame has no FCS; if it's 4, we assume
+ * it has an FCS; if it's anything else (such as -1, which means "maybe
+ * it does, maybe it doesn't"), we try to infer whether it has an FCS.
+ */
+void
+add_ethernet_trailer(proto_tree *fh_tree, int trailer_id, tvbuff_t *tvb,
+ tvbuff_t *trailer_tvb, int fcs_len)
+{
+ /* If there're some bytes left over, show those bytes as a trailer.
+
+ However, if the Ethernet frame was claimed to have had 64 or more
+ bytes - i.e., it was at least an FCS worth of data longer than
+ the minimum payload size - assume the last 4 bytes of the trailer
+ are an FCS. */
+ if (trailer_tvb && fh_tree) {
+ guint trailer_length, trailer_reported_length;
+ gboolean has_fcs = FALSE;
+
+ trailer_length = tvb_length(trailer_tvb);
+ trailer_reported_length = tvb_reported_length(trailer_tvb);
+ if (fcs_len != 0) {
+ /* If fcs_len is 4, we assume we definitely have an FCS.
+ Otherwise, then, if the frame is big enough that, if we
+ have a trailer, it probably inclues an FCS, and we have
+ enough space in the trailer for the FCS, we assume we
+ have an FCS.
+
+ "Big enough" means 64 bytes or more; any frame that big
+ needs no trailer, as there's no need to pad an Ethernet
+ packet past 60 bytes.
+
+ The trailer must be at least 4 bytes long to have enough
+ space for an FCS. */
+
+ if (fcs_len == 4 || (tvb_reported_length(tvb) >= 64 &&
+ trailer_reported_length >= 4)) {
+ /* Either we know we have an FCS, or we believe we have an FCS. */
+ if (trailer_length < trailer_reported_length) {
+ /* The packet is claimed to have enough data for a 4-byte FCS,
+ but we didn't capture all of the packet.
+ Slice off the 4-byte FCS from the reported length, and
+ trim the captured length so it's no more than the reported
+ length; that will slice off what of the FCS, if any, is
+ in the captured packet. */
+ trailer_reported_length -= 4;
+ if (trailer_length > trailer_reported_length)
+ trailer_length = trailer_reported_length;
+ has_fcs = TRUE;
+ } else {
+ /* We captured all of the packet, including what appears to
+ be a 4-byte FCS. Slice it off. */
+ trailer_length -= 4;
+ trailer_reported_length -= 4;
+ has_fcs = TRUE;
+ }
+ }
+ }
+ if (trailer_length != 0) {
+ proto_tree_add_item(fh_tree, trailer_id, trailer_tvb, 0,
+ trailer_length, FALSE);
+ }
+ if (has_fcs) {
+ guint32 sent_fcs = tvb_get_ntohl(trailer_tvb, trailer_length);
+ guint32 fcs = crc32_tvb_802(tvb, tvb_length(tvb) - 4);
+ if (fcs == sent_fcs) {
+ proto_tree_add_text(fh_tree, trailer_tvb, trailer_length, 4,
+ "Frame check sequence: 0x%08x (correct)",
+ sent_fcs);
+ } else {
+ proto_tree_add_text(fh_tree, trailer_tvb, trailer_length, 4,
+ "Frame check sequence: 0x%08x (incorrect, should be 0x%08x)",
+ sent_fcs, fcs);
+ }
+ }
}
}
+/* Called for the Ethernet Wiretap encapsulation type; pass the FCS length
+ reported to us. */
+static void
+dissect_eth_maybefcs(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
+{
+ dissect_eth_common(tvb, pinfo, tree, pinfo->pseudo_header->eth.fcs_len);
+}
+
+/* Called by other dissectors - for now, we assume Ethernet encapsulated
+ inside other protocols doesn't include the FCS. */
+static void
+dissect_eth(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
+{
+ dissect_eth_common(tvb, pinfo, tree, 0);
+}
+
void
proto_register_eth(void)
{
&ett_ieee8023,
&ett_ether2,
};
+ module_t *eth_module;
proto_eth = proto_register_protocol("Ethernet", "Ethernet", "eth");
proto_register_field_array(proto_eth, hf, array_length(hf));
proto_register_subtree_array(ett, array_length(ett));
+ /* Register configuration preferences */
+ eth_module = prefs_register_protocol(proto_eth, NULL);
+ 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;
+ 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("wtap_encap", WTAP_ENCAP_ETHERNET, eth_handle);
dissector_add("ethertype", ETHERTYPE_ETHBRIDGE, eth_handle);
dissector_add("chdlctype", ETHERTYPE_ETHBRIDGE, eth_handle);
dissector_add("gre.proto", ETHERTYPE_ETHBRIDGE, eth_handle);
git.samba.org / obnox / wireshark / wip.git / blobdiff