forked from osmocom/wireshark
![Dario Lombardo](/assets/img/avatar_default.png)
Change-Id: I92c94448e6641716d03158a5f332c8b53709423a Reviewed-on: https://code.wireshark.org/review/25756 Petri-Dish: Dario Lombardo <lomato@gmail.com> Reviewed-by: Anders Broman <a.broman58@gmail.com>
424 lines
14 KiB
C
424 lines
14 KiB
C
/* packet-isl.c
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* Routines for Cisco ISL Ethernet header disassembly
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*
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* Wireshark - Network traffic analyzer
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* By Gerald Combs <gerald@wireshark.org>
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* Copyright 1998 Gerald Combs
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*
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* SPDX-License-Identifier: GPL-2.0-or-later
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*/
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#include "config.h"
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#include <epan/packet.h>
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#include <epan/exceptions.h>
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#include <epan/show_exception.h>
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#include <epan/capture_dissectors.h>
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#include "packet-isl.h"
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#include "packet-eth.h"
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#include "packet-tr.h"
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void proto_register_isl(void);
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void proto_reg_handoff_isl(void);
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/*
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* See
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*
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* http://www.cisco.com/c/en/us/support/docs/lan-switching/8021q/17056-741-4.html
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*
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* and
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*
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* http://docstore.mik.ua/univercd/cc/td/doc/product/lan/trsrb/frames.htm
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*
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* for information on ISL.
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*/
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static int proto_isl = -1;
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static int hf_isl_dst = -1;
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static int hf_isl_type = -1;
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static int hf_isl_user_eth = -1;
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static int hf_isl_user = -1;
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static int hf_isl_src = -1;
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static int hf_isl_addr = -1;
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static int hf_isl_len = -1;
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static int hf_isl_hsa = -1;
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static int hf_isl_dsap = -1;
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static int hf_isl_ssap = -1;
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static int hf_isl_control = -1;
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static int hf_isl_vlan_id = -1;
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static int hf_isl_bpdu = -1;
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static int hf_isl_index = -1;
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static int hf_isl_reserved = -1;
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/* static int hf_isl_crc = -1; */
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static int hf_isl_src_vlan_id = -1;
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static int hf_isl_explorer = -1;
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static int hf_isl_dst_route_descriptor = -1;
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static int hf_isl_src_route_descriptor = -1;
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static int hf_isl_fcs_not_incl = -1;
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static int hf_isl_esize = -1;
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static int hf_isl_trailer = -1;
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static gint ett_isl = -1;
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static gint ett_isl_dst = -1;
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#define ISL_HEADER_SIZE 26
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#define TYPE_ETHER 0x0
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#define TYPE_TR 0x1
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#define TYPE_FDDI 0x2
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#define TYPE_ATM 0x3
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#define USER_PRIORITY_NORMAL 0x0
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#define USER_PRIORITY_1 0x1
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#define USER_PRIORITY_2 0x2
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#define USER_PRIORITY_HIGHEST 0x3
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static dissector_handle_t eth_withfcs_handle;
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static dissector_handle_t tr_handle;
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static capture_dissector_handle_t eth_cap_handle;
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static capture_dissector_handle_t tr_cap_handle;
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static gboolean
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capture_isl(const guchar *pd, int offset, int len, capture_packet_info_t *cpinfo, const union wtap_pseudo_header *pseudo_header _U_)
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{
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guint8 type;
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if (!BYTES_ARE_IN_FRAME(offset, len, ISL_HEADER_SIZE))
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return FALSE;
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type = (pd[offset+5] >> 4)&0x0F;
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switch (type) {
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case TYPE_ETHER:
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offset += 14+12; /* skip the header */
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return call_capture_dissector(eth_cap_handle, pd, offset, len, cpinfo, pseudo_header);
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case TYPE_TR:
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offset += 14+17; /* skip the header */
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return call_capture_dissector(tr_cap_handle, pd, offset, len, cpinfo, pseudo_header);
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break;
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}
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return FALSE;
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}
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static const value_string type_vals[] = {
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{TYPE_ETHER, "Ethernet"},
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{TYPE_TR, "Token-Ring"},
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{TYPE_FDDI, "FDDI"},
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{TYPE_ATM, "ATM"},
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{0, NULL}
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};
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static const value_string user_vals[] = {
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{USER_PRIORITY_NORMAL, "Normal Priority"},
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{USER_PRIORITY_1, "Priority 1"},
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{USER_PRIORITY_2, "Priority 2"},
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{USER_PRIORITY_HIGHEST, "Highest Priority"},
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{0, NULL}
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};
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static const true_false_string explorer_tfs = {
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"Explorer frame",
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"Data frame"
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};
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void
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dissect_isl(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, int fcs_len)
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{
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proto_tree *volatile fh_tree = NULL;
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proto_tree *dst_tree;
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proto_item *ti, *hidden_item;
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volatile guint8 type;
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volatile guint16 length;
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gint captured_length;
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tvbuff_t *volatile payload_tvb = NULL;
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tvbuff_t *volatile next_tvb;
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tvbuff_t *volatile trailer_tvb = NULL;
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const char *saved_proto;
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col_set_str(pinfo->cinfo, COL_PROTOCOL, "ISL");
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col_clear(pinfo->cinfo, COL_INFO);
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type = (tvb_get_guint8(tvb, 5) >> 4)&0x0F;
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if (tree) {
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ti = proto_tree_add_protocol_format(tree, proto_isl, tvb, 0, ISL_HEADER_SIZE,
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"ISL");
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fh_tree = proto_item_add_subtree(ti, ett_isl);
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ti = proto_tree_add_item(fh_tree, hf_isl_dst, tvb, 0, 6, ENC_NA);
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hidden_item = proto_tree_add_item(fh_tree, hf_isl_addr, tvb, 0, 6, ENC_NA);
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PROTO_ITEM_SET_HIDDEN(hidden_item);
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dst_tree = proto_item_add_subtree(ti, ett_isl_dst);
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proto_tree_add_item(dst_tree, hf_isl_type, tvb, 5, 1, ENC_BIG_ENDIAN);
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switch (type) {
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case TYPE_ETHER:
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proto_tree_add_item(dst_tree, hf_isl_user_eth, tvb, 5, 1, ENC_BIG_ENDIAN);
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break;
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default:
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/* XXX - the spec appears to indicate that the "User" field is
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used for TYPE_TR to distinguish between types of packets. */
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proto_tree_add_item(dst_tree, hf_isl_user, tvb, 5, 1, ENC_BIG_ENDIAN);
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break;
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}
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proto_tree_add_item(fh_tree, hf_isl_src, tvb, 6, 6, ENC_NA);
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hidden_item = proto_tree_add_item(fh_tree, hf_isl_addr, tvb, 6, 6, ENC_NA);
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PROTO_ITEM_SET_HIDDEN(hidden_item);
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}
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length = tvb_get_ntohs(tvb, 12);
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if (tree)
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proto_tree_add_uint(fh_tree, hf_isl_len, tvb, 12, 2, length);
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if (length != 0) {
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/* The length field was set; it's like an 802.3 length field, so
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treat it similarly, by constructing a tvbuff containing only
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the data specified by the length field. */
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TRY {
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payload_tvb = tvb_new_subset_length(tvb, 14, length);
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trailer_tvb = tvb_new_subset_remaining(tvb, 14 + length);
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}
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CATCH_BOUNDS_ERRORS {
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/* Either:
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the packet doesn't have "length" bytes worth of
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captured data left in it - or it may not even have
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"length" bytes worth of data in it, period -
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so the "tvb_new_subset_length_caplen()" creating "payload_tvb"
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threw an exception
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or
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the packet has exactly "length" bytes worth of
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captured data left in it, so the "tvb_new_subset_remaining()"
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creating "trailer_tvb" threw an exception.
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In either case, this means that all the data in the frame
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is within the length value, so we give all the data to the
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next protocol and have no trailer. */
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payload_tvb = tvb_new_subset_length_caplen(tvb, 14, -1, length);
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trailer_tvb = NULL;
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}
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ENDTRY;
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} else {
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/* The length field is 0; make it the length remaining in the packet
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after the first 14 bytes. */
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length = tvb_reported_length_remaining(tvb, 14);
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payload_tvb = tvb_new_subset_remaining(tvb, 14);
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trailer_tvb = NULL;
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}
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if (tree) {
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/* This part looks sort of like a SNAP-encapsulated LLC header... */
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proto_tree_add_item(fh_tree, hf_isl_dsap, payload_tvb, 0, 1, ENC_BIG_ENDIAN);
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proto_tree_add_item(fh_tree, hf_isl_ssap, payload_tvb, 1, 1, ENC_BIG_ENDIAN);
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proto_tree_add_item(fh_tree, hf_isl_control, payload_tvb, 2, 1, ENC_BIG_ENDIAN);
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/* ...but this is the manufacturer's ID portion of the source address
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field (which is, admittedly, an OUI). */
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proto_tree_add_item(fh_tree, hf_isl_hsa, payload_tvb, 3, 3, ENC_BIG_ENDIAN);
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}
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col_add_fstr(pinfo->cinfo, COL_INFO, "VLAN ID: %u",
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tvb_get_ntohs(tvb, 20) >> 1);
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if (tree) {
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proto_tree_add_item(fh_tree, hf_isl_vlan_id, payload_tvb, 6, 2, ENC_BIG_ENDIAN);
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proto_tree_add_item(fh_tree, hf_isl_bpdu, payload_tvb, 6, 2, ENC_BIG_ENDIAN);
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proto_tree_add_item(fh_tree, hf_isl_index, payload_tvb, 8, 2, ENC_BIG_ENDIAN);
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proto_tree_add_item(fh_tree, hf_isl_reserved, payload_tvb, 10, 2, ENC_BIG_ENDIAN);
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}
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switch (type) {
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case TYPE_ETHER:
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/* The length of the encapsulated frame is the length from the
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header, minus 12 bytes for the part of the ISL header that
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follows the length. */
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if (length >= 12) {
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/* Well, we at least had that much data in the frame. Try
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dissecting what's left as an Ethernet frame. */
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length -= 12;
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/* Trim the captured length. */
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captured_length = tvb_captured_length_remaining(payload_tvb, 12);
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/* Make sure it's not bigger than the actual length. */
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if (captured_length > length)
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captured_length = length;
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next_tvb = tvb_new_subset_length_caplen(payload_tvb, 12, captured_length, length);
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/* Dissect the payload as an Ethernet frame.
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Catch BoundsError and ReportedBoundsError, so that if the
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reported length of "next_tvb" was reduced by some dissector
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before an exception was thrown, we can still put in an item
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for the trailer. */
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saved_proto = pinfo->current_proto;
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TRY {
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/* Frames encapsulated in ISL include an FCS. */
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call_dissector(eth_withfcs_handle, next_tvb, pinfo, tree);
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}
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CATCH_NONFATAL_ERRORS {
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/* Somebody threw an exception that indicates a problem with
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the payload, but doesn't indicate anything that would
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keep us from dissecting the trailer.
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Show the exception, and then drive on to show the trailer,
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restoring the protocol value that was in effect before we
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called the subdissector.
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*/
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show_exception(next_tvb, pinfo, tree, EXCEPT_CODE, GET_MESSAGE);
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pinfo->current_proto = saved_proto;
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}
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ENDTRY;
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/* Now add the Ethernet trailer and FCS.
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XXX - do this only if we're encapsulated in Ethernet? */
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add_ethernet_trailer(pinfo, tree, fh_tree, hf_isl_trailer, tvb, trailer_tvb, fcs_len);
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}
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break;
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case TYPE_TR:
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if (tree) {
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proto_tree_add_item(fh_tree, hf_isl_src_vlan_id, payload_tvb, 10, 2, ENC_BIG_ENDIAN);
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proto_tree_add_item(fh_tree, hf_isl_explorer, payload_tvb, 10, 2, ENC_BIG_ENDIAN);
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proto_tree_add_item(fh_tree, hf_isl_dst_route_descriptor, payload_tvb, 12, 2, ENC_BIG_ENDIAN);
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proto_tree_add_item(fh_tree, hf_isl_src_route_descriptor, payload_tvb, 14, 2, ENC_BIG_ENDIAN);
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/* This doesn't appear to be present in at least one capture I've seen. */
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proto_tree_add_item(fh_tree, hf_isl_fcs_not_incl, payload_tvb, 16, 1, ENC_BIG_ENDIAN);
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proto_tree_add_item(fh_tree, hf_isl_esize, payload_tvb, 16, 1, ENC_BIG_ENDIAN);
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}
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next_tvb = tvb_new_subset_remaining(payload_tvb, 17);
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call_dissector(tr_handle, next_tvb, pinfo, tree);
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break;
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default:
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next_tvb = tvb_new_subset_remaining(payload_tvb, 12);
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call_data_dissector(next_tvb, pinfo, tree);
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break;
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}
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}
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void
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proto_register_isl(void)
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{
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static hf_register_info hf[] = {
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{ &hf_isl_dst,
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{ "Destination", "isl.dst", FT_ETHER, BASE_NONE, NULL, 0x0,
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"Destination Address", HFILL }},
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{ &hf_isl_type,
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{ "Type", "isl.type", FT_UINT8, BASE_DEC,
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VALS(type_vals), 0xF0, NULL, HFILL }},
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{ &hf_isl_user_eth,
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{ "User", "isl.user_eth", FT_UINT8, BASE_DEC,
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VALS(user_vals), 0x03, "Priority while passing through switch", HFILL }},
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{ &hf_isl_user,
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{ "User", "isl.user", FT_UINT8, BASE_HEX, NULL, 0x0F,
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"User-defined bits", HFILL }},
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{ &hf_isl_src,
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{ "Source", "isl.src", FT_ETHER, BASE_NONE, NULL, 0x0,
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"Source Hardware Address", HFILL }},
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{ &hf_isl_addr,
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{ "Source or Destination Address", "isl.addr", FT_ETHER, BASE_NONE, NULL, 0x0,
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"Source or Destination Hardware Address", HFILL }},
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{ &hf_isl_len,
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{ "Length", "isl.len", FT_UINT16, BASE_DEC, NULL, 0x0,
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NULL, HFILL }},
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{ &hf_isl_hsa,
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{ "HSA", "isl.hsa", FT_UINT24, BASE_HEX, NULL, 0x0,
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"High bits of source address", HFILL }},
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{ &hf_isl_dsap,
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{ "DSAP", "isl.dsap", FT_UINT8, BASE_HEX, NULL, 0x0,
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NULL, HFILL }},
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{ &hf_isl_ssap,
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{ "SSAP", "isl.ssap", FT_UINT8, BASE_HEX, NULL, 0x0,
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NULL, HFILL }},
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{ &hf_isl_control,
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{ "Control", "isl.control", FT_UINT8, BASE_HEX, NULL, 0x0,
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NULL, HFILL }},
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{ &hf_isl_vlan_id,
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{ "VLAN ID", "isl.vlan_id", FT_UINT16, BASE_DEC, NULL,
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0xFFFE, "Virtual LAN ID (Color)", HFILL }},
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{ &hf_isl_bpdu,
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{ "BPDU/CDP/VTP", "isl.bpdu", FT_BOOLEAN, 16,
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TFS(&tfs_yes_no), 0x0001, "BPDU/CDP/VTP indicator", HFILL }},
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{ &hf_isl_index,
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{ "Index", "isl.index", FT_UINT16, BASE_DEC, NULL, 0x0,
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"Port index of packet source", HFILL }},
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{ &hf_isl_reserved,
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{ "Reserved", "isl.reserved", FT_UINT16, BASE_HEX, NULL, 0x0,
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"ISL Reserved", HFILL }},
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#if 0
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{ &hf_isl_crc,
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{ "CRC", "isl.crc", FT_UINT32, BASE_HEX, NULL, 0x0,
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"CRC field of encapsulated frame", HFILL }},
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#endif
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{ &hf_isl_src_vlan_id,
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{ "Source VLAN ID", "isl.src_vlan_id", FT_UINT16, BASE_DEC, NULL,
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0xFFFE, "Source Virtual LAN ID (Color)", HFILL }},
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{ &hf_isl_explorer,
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{ "Explorer", "isl.explorer", FT_BOOLEAN, 16,
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TFS(&explorer_tfs), 0x0001, NULL, HFILL }},
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{ &hf_isl_dst_route_descriptor,
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{ "Destination route descriptor", "isl.dst_route_desc",
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FT_UINT16, BASE_HEX, NULL, 0x0,
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"Route descriptor to be used for forwarding", HFILL }},
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{ &hf_isl_src_route_descriptor,
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{ "Source-route descriptor", "isl.src_route_desc",
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FT_UINT16, BASE_HEX, NULL, 0x0,
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"Route descriptor to be used for source learning", HFILL }},
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{ &hf_isl_fcs_not_incl,
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{ "FCS Not Included", "isl.fcs_not_incl", FT_BOOLEAN, 9,
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NULL, 0x40, NULL, HFILL }},
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{ &hf_isl_esize,
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{ "Esize", "isl.esize", FT_UINT8, BASE_DEC, NULL,
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0x3F, "Frame size for frames less than 64 bytes", HFILL }},
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{ &hf_isl_trailer,
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{ "Trailer", "isl.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_isl,
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&ett_isl_dst,
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};
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proto_isl = proto_register_protocol("Cisco ISL", "ISL", "isl");
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proto_register_field_array(proto_isl, hf, array_length(hf));
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proto_register_subtree_array(ett, array_length(ett));
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register_capture_dissector("isl", capture_isl, proto_isl);
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}
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void
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proto_reg_handoff_isl(void)
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{
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/*
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* Get handles for the Ethernet and Token Ring dissectors.
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*/
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eth_withfcs_handle = find_dissector_add_dependency("eth_withfcs", proto_isl);
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tr_handle = find_dissector_add_dependency("tr", proto_isl);
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eth_cap_handle = find_capture_dissector("eth");
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tr_cap_handle = find_capture_dissector("tr");
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}
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/*
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* Editor modelines - http://www.wireshark.org/tools/modelines.html
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*
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* Local Variables:
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* c-basic-offset: 2
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* tab-width: 8
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* indent-tabs-mode: nil
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* End:
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*
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* ex: set shiftwidth=2 tabstop=8 expandtab:
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* :indentSize=2:tabSize=8:noTabs=true:
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*/
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