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-rw-r--r--epan/dissectors/packet-isl.c423
1 files changed, 423 insertions, 0 deletions
diff --git a/epan/dissectors/packet-isl.c b/epan/dissectors/packet-isl.c
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+++ b/epan/dissectors/packet-isl.c
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+/* packet-isl.c
+ * Routines for Cisco ISL Ethernet header disassembly
+ *
+ * Wireshark - Network traffic analyzer
+ * By Gerald Combs <gerald@wireshark.org>
+ * Copyright 1998 Gerald Combs
+ *
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ */
+
+#include "config.h"
+
+#include <epan/packet.h>
+#include <epan/exceptions.h>
+#include <epan/show_exception.h>
+#include <epan/capture_dissectors.h>
+
+#include "packet-isl.h"
+#include "packet-eth.h"
+#include "packet-tr.h"
+
+void proto_register_isl(void);
+void proto_reg_handoff_isl(void);
+
+/*
+ * See
+ *
+ * http://www.cisco.com/c/en/us/support/docs/lan-switching/8021q/17056-741-4.html
+ *
+ * and
+ *
+ * http://docstore.mik.ua/univercd/cc/td/doc/product/lan/trsrb/frames.htm
+ *
+ * for information on ISL.
+ */
+static int proto_isl = -1;
+static int hf_isl_dst = -1;
+static int hf_isl_type = -1;
+static int hf_isl_user_eth = -1;
+static int hf_isl_user = -1;
+static int hf_isl_src = -1;
+static int hf_isl_addr = -1;
+static int hf_isl_len = -1;
+static int hf_isl_hsa = -1;
+static int hf_isl_dsap = -1;
+static int hf_isl_ssap = -1;
+static int hf_isl_control = -1;
+static int hf_isl_vlan_id = -1;
+static int hf_isl_bpdu = -1;
+static int hf_isl_index = -1;
+static int hf_isl_reserved = -1;
+/* static int hf_isl_crc = -1; */
+static int hf_isl_src_vlan_id = -1;
+static int hf_isl_explorer = -1;
+static int hf_isl_dst_route_descriptor = -1;
+static int hf_isl_src_route_descriptor = -1;
+static int hf_isl_fcs_not_incl = -1;
+static int hf_isl_esize = -1;
+static int hf_isl_trailer = -1;
+
+static gint ett_isl = -1;
+static gint ett_isl_dst = -1;
+
+#define ISL_HEADER_SIZE 26
+
+#define TYPE_ETHER 0x0
+#define TYPE_TR 0x1
+#define TYPE_FDDI 0x2
+#define TYPE_ATM 0x3
+
+#define USER_PRIORITY_NORMAL 0x0
+#define USER_PRIORITY_1 0x1
+#define USER_PRIORITY_2 0x2
+#define USER_PRIORITY_HIGHEST 0x3
+
+static dissector_handle_t eth_withfcs_handle;
+static dissector_handle_t tr_handle;
+
+static capture_dissector_handle_t eth_cap_handle;
+static capture_dissector_handle_t tr_cap_handle;
+
+static gboolean
+capture_isl(const guchar *pd, int offset, int len, capture_packet_info_t *cpinfo, const union wtap_pseudo_header *pseudo_header _U_)
+{
+ guint8 type;
+
+ if (!BYTES_ARE_IN_FRAME(offset, len, ISL_HEADER_SIZE))
+ return FALSE;
+
+ type = (pd[offset+5] >> 4)&0x0F;
+
+ switch (type) {
+
+ case TYPE_ETHER:
+ offset += 14+12; /* skip the header */
+ return call_capture_dissector(eth_cap_handle, pd, offset, len, cpinfo, pseudo_header);
+
+ case TYPE_TR:
+ offset += 14+17; /* skip the header */
+ return call_capture_dissector(tr_cap_handle, pd, offset, len, cpinfo, pseudo_header);
+ break;
+ }
+
+ return FALSE;
+}
+
+static const value_string type_vals[] = {
+ {TYPE_ETHER, "Ethernet"},
+ {TYPE_TR, "Token-Ring"},
+ {TYPE_FDDI, "FDDI"},
+ {TYPE_ATM, "ATM"},
+ {0, NULL}
+};
+
+static const value_string user_vals[] = {
+ {USER_PRIORITY_NORMAL, "Normal Priority"},
+ {USER_PRIORITY_1, "Priority 1"},
+ {USER_PRIORITY_2, "Priority 2"},
+ {USER_PRIORITY_HIGHEST, "Highest Priority"},
+ {0, NULL}
+};
+
+static const true_false_string explorer_tfs = {
+ "Explorer frame",
+ "Data frame"
+};
+
+void
+dissect_isl(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, int fcs_len)
+{
+ proto_tree *volatile fh_tree = NULL;
+ proto_tree *dst_tree;
+ proto_item *ti, *hidden_item;
+ volatile guint8 type;
+ volatile guint16 length;
+ gint captured_length;
+ tvbuff_t *volatile payload_tvb = NULL;
+ tvbuff_t *volatile next_tvb;
+ tvbuff_t *volatile trailer_tvb = NULL;
+ const char *saved_proto;
+
+ col_set_str(pinfo->cinfo, COL_PROTOCOL, "ISL");
+ col_clear(pinfo->cinfo, COL_INFO);
+
+ type = (tvb_get_guint8(tvb, 5) >> 4)&0x0F;
+
+ if (tree) {
+ ti = proto_tree_add_protocol_format(tree, proto_isl, tvb, 0, ISL_HEADER_SIZE,
+ "ISL");
+ fh_tree = proto_item_add_subtree(ti, ett_isl);
+
+ ti = proto_tree_add_item(fh_tree, hf_isl_dst, tvb, 0, 6, ENC_NA);
+ hidden_item = proto_tree_add_item(fh_tree, hf_isl_addr, tvb, 0, 6, ENC_NA);
+ proto_item_set_hidden(hidden_item);
+ dst_tree = proto_item_add_subtree(ti, ett_isl_dst);
+ proto_tree_add_item(dst_tree, hf_isl_type, tvb, 5, 1, ENC_BIG_ENDIAN);
+
+ switch (type) {
+
+ case TYPE_ETHER:
+ proto_tree_add_item(dst_tree, hf_isl_user_eth, tvb, 5, 1, ENC_BIG_ENDIAN);
+ break;
+
+ default:
+ /* XXX - the spec appears to indicate that the "User" field is
+ used for TYPE_TR to distinguish between types of packets. */
+ proto_tree_add_item(dst_tree, hf_isl_user, tvb, 5, 1, ENC_BIG_ENDIAN);
+ break;
+ }
+ proto_tree_add_item(fh_tree, hf_isl_src, tvb, 6, 6, ENC_NA);
+ hidden_item = proto_tree_add_item(fh_tree, hf_isl_addr, tvb, 6, 6, ENC_NA);
+ proto_item_set_hidden(hidden_item);
+ }
+ length = tvb_get_ntohs(tvb, 12);
+ if (tree)
+ proto_tree_add_uint(fh_tree, hf_isl_len, tvb, 12, 2, length);
+
+ if (length != 0) {
+ /* The length field was set; it's like an 802.3 length field, so
+ treat it similarly, by constructing a tvbuff containing only
+ the data specified by the length field. */
+
+ TRY {
+ payload_tvb = tvb_new_subset_length(tvb, 14, length);
+ trailer_tvb = tvb_new_subset_remaining(tvb, 14 + length);
+ }
+ CATCH_BOUNDS_ERRORS {
+ /* 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_length_caplen()" creating "payload_tvb"
+ threw an exception
+
+ or
+
+ the packet has exactly "length" bytes worth of
+ captured data left in it, so the "tvb_new_subset_remaining()"
+ 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. */
+ payload_tvb = tvb_new_subset_length_caplen(tvb, 14, -1, length);
+ trailer_tvb = NULL;
+ }
+ ENDTRY;
+ } else {
+ /* The length field is 0; make it the length remaining in the packet
+ after the first 14 bytes. */
+ length = tvb_reported_length_remaining(tvb, 14);
+ payload_tvb = tvb_new_subset_remaining(tvb, 14);
+ trailer_tvb = NULL;
+ }
+
+ if (tree) {
+ /* This part looks sort of like a SNAP-encapsulated LLC header... */
+ proto_tree_add_item(fh_tree, hf_isl_dsap, payload_tvb, 0, 1, ENC_BIG_ENDIAN);
+ proto_tree_add_item(fh_tree, hf_isl_ssap, payload_tvb, 1, 1, ENC_BIG_ENDIAN);
+ proto_tree_add_item(fh_tree, hf_isl_control, payload_tvb, 2, 1, ENC_BIG_ENDIAN);
+
+ /* ...but this is the manufacturer's ID portion of the source address
+ field (which is, admittedly, an OUI). */
+ proto_tree_add_item(fh_tree, hf_isl_hsa, payload_tvb, 3, 3, ENC_BIG_ENDIAN);
+ }
+ col_add_fstr(pinfo->cinfo, COL_INFO, "VLAN ID: %u",
+ tvb_get_ntohs(tvb, 20) >> 1);
+ if (tree) {
+ proto_tree_add_item(fh_tree, hf_isl_vlan_id, payload_tvb, 6, 2, ENC_BIG_ENDIAN);
+ proto_tree_add_item(fh_tree, hf_isl_bpdu, payload_tvb, 6, 2, ENC_BIG_ENDIAN);
+ proto_tree_add_item(fh_tree, hf_isl_index, payload_tvb, 8, 2, ENC_BIG_ENDIAN);
+ proto_tree_add_item(fh_tree, hf_isl_reserved, payload_tvb, 10, 2, ENC_BIG_ENDIAN);
+ }
+
+ switch (type) {
+
+ case TYPE_ETHER:
+ /* The length of the encapsulated frame is the length from the
+ header, minus 12 bytes for the part of the ISL header that
+ follows the length. */
+ if (length >= 12) {
+ /* Well, we at least had that much data in the frame. Try
+ dissecting what's left as an Ethernet frame. */
+ length -= 12;
+
+ /* Trim the captured length. */
+ captured_length = tvb_captured_length_remaining(payload_tvb, 12);
+
+ /* Make sure it's not bigger than the actual length. */
+ if (captured_length > length)
+ captured_length = length;
+
+ next_tvb = tvb_new_subset_length_caplen(payload_tvb, 12, captured_length, length);
+
+ /* Dissect the payload as an Ethernet 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. */
+ saved_proto = pinfo->current_proto;
+ TRY {
+ /* Frames encapsulated in ISL include an FCS. */
+ call_dissector(eth_withfcs_handle, next_tvb, pinfo, tree);
+ }
+ CATCH_NONFATAL_ERRORS {
+ /* Somebody threw an exception that indicates a problem with
+ the payload, but doesn't indicate anything that would
+ keep us from dissecting the trailer.
+
+ Show the exception, and then drive on to show the trailer,
+ restoring the protocol value that was in effect before we
+ called the subdissector.
+ */
+
+ show_exception(next_tvb, pinfo, tree, EXCEPT_CODE, GET_MESSAGE);
+ pinfo->current_proto = saved_proto;
+ }
+ ENDTRY;
+
+ /* Now add the Ethernet trailer and FCS.
+ XXX - do this only if we're encapsulated in Ethernet? */
+ add_ethernet_trailer(pinfo, tree, fh_tree, hf_isl_trailer, tvb, trailer_tvb, fcs_len);
+ }
+ break;
+
+ case TYPE_TR:
+ if (tree) {
+ proto_tree_add_item(fh_tree, hf_isl_src_vlan_id, payload_tvb, 10, 2, ENC_BIG_ENDIAN);
+ proto_tree_add_item(fh_tree, hf_isl_explorer, payload_tvb, 10, 2, ENC_BIG_ENDIAN);
+ proto_tree_add_item(fh_tree, hf_isl_dst_route_descriptor, payload_tvb, 12, 2, ENC_BIG_ENDIAN);
+ proto_tree_add_item(fh_tree, hf_isl_src_route_descriptor, payload_tvb, 14, 2, ENC_BIG_ENDIAN);
+ /* This doesn't appear to be present in at least one capture I've seen. */
+ proto_tree_add_item(fh_tree, hf_isl_fcs_not_incl, payload_tvb, 16, 1, ENC_BIG_ENDIAN);
+ proto_tree_add_item(fh_tree, hf_isl_esize, payload_tvb, 16, 1, ENC_BIG_ENDIAN);
+ }
+ next_tvb = tvb_new_subset_remaining(payload_tvb, 17);
+ call_dissector(tr_handle, next_tvb, pinfo, tree);
+ break;
+
+ default:
+ next_tvb = tvb_new_subset_remaining(payload_tvb, 12);
+ call_data_dissector(next_tvb, pinfo, tree);
+ break;
+ }
+}
+
+void
+proto_register_isl(void)
+{
+ static hf_register_info hf[] = {
+ { &hf_isl_dst,
+ { "Destination", "isl.dst", FT_ETHER, BASE_NONE, NULL, 0x0,
+ "Destination Address", HFILL }},
+ { &hf_isl_type,
+ { "Type", "isl.type", FT_UINT8, BASE_DEC,
+ VALS(type_vals), 0xF0, NULL, HFILL }},
+ { &hf_isl_user_eth,
+ { "User", "isl.user_eth", FT_UINT8, BASE_DEC,
+ VALS(user_vals), 0x03, "Priority while passing through switch", HFILL }},
+ { &hf_isl_user,
+ { "User", "isl.user", FT_UINT8, BASE_HEX, NULL, 0x0F,
+ "User-defined bits", HFILL }},
+ { &hf_isl_src,
+ { "Source", "isl.src", FT_ETHER, BASE_NONE, NULL, 0x0,
+ "Source Hardware Address", HFILL }},
+ { &hf_isl_addr,
+ { "Source or Destination Address", "isl.addr", FT_ETHER, BASE_NONE, NULL, 0x0,
+ "Source or Destination Hardware Address", HFILL }},
+ { &hf_isl_len,
+ { "Length", "isl.len", FT_UINT16, BASE_DEC, NULL, 0x0,
+ NULL, HFILL }},
+ { &hf_isl_hsa,
+ { "HSA", "isl.hsa", FT_UINT24, BASE_HEX, NULL, 0x0,
+ "High bits of source address", HFILL }},
+ { &hf_isl_dsap,
+ { "DSAP", "isl.dsap", FT_UINT8, BASE_HEX, NULL, 0x0,
+ NULL, HFILL }},
+ { &hf_isl_ssap,
+ { "SSAP", "isl.ssap", FT_UINT8, BASE_HEX, NULL, 0x0,
+ NULL, HFILL }},
+ { &hf_isl_control,
+ { "Control", "isl.control", FT_UINT8, BASE_HEX, NULL, 0x0,
+ NULL, HFILL }},
+ { &hf_isl_vlan_id,
+ { "VLAN ID", "isl.vlan_id", FT_UINT16, BASE_DEC, NULL,
+ 0xFFFE, "Virtual LAN ID (Color)", HFILL }},
+ { &hf_isl_bpdu,
+ { "BPDU/CDP/VTP", "isl.bpdu", FT_BOOLEAN, 16,
+ TFS(&tfs_yes_no), 0x0001, "BPDU/CDP/VTP indicator", HFILL }},
+ { &hf_isl_index,
+ { "Index", "isl.index", FT_UINT16, BASE_DEC, NULL, 0x0,
+ "Port index of packet source", HFILL }},
+ { &hf_isl_reserved,
+ { "Reserved", "isl.reserved", FT_UINT16, BASE_HEX, NULL, 0x0,
+ "ISL Reserved", HFILL }},
+#if 0
+ { &hf_isl_crc,
+ { "CRC", "isl.crc", FT_UINT32, BASE_HEX, NULL, 0x0,
+ "CRC field of encapsulated frame", HFILL }},
+#endif
+ { &hf_isl_src_vlan_id,
+ { "Source VLAN ID", "isl.src_vlan_id", FT_UINT16, BASE_DEC, NULL,
+ 0xFFFE, "Source Virtual LAN ID (Color)", HFILL }},
+ { &hf_isl_explorer,
+ { "Explorer", "isl.explorer", FT_BOOLEAN, 16,
+ TFS(&explorer_tfs), 0x0001, NULL, HFILL }},
+ { &hf_isl_dst_route_descriptor,
+ { "Destination route descriptor", "isl.dst_route_desc",
+ FT_UINT16, BASE_HEX, NULL, 0x0,
+ "Route descriptor to be used for forwarding", HFILL }},
+ { &hf_isl_src_route_descriptor,
+ { "Source-route descriptor", "isl.src_route_desc",
+ FT_UINT16, BASE_HEX, NULL, 0x0,
+ "Route descriptor to be used for source learning", HFILL }},
+ { &hf_isl_fcs_not_incl,
+ { "FCS Not Included", "isl.fcs_not_incl", FT_BOOLEAN, 8,
+ NULL, 0x40, NULL, HFILL }},
+ { &hf_isl_esize,
+ { "Esize", "isl.esize", FT_UINT8, BASE_DEC, NULL,
+ 0x3F, "Frame size for frames less than 64 bytes", HFILL }},
+ { &hf_isl_trailer,
+ { "Trailer", "isl.trailer", FT_BYTES, BASE_NONE, NULL, 0x0,
+ "Ethernet Trailer or Checksum", HFILL }},
+ };
+ static gint *ett[] = {
+ &ett_isl,
+ &ett_isl_dst,
+ };
+
+ proto_isl = proto_register_protocol("Cisco ISL", "ISL", "isl");
+ proto_register_field_array(proto_isl, hf, array_length(hf));
+ proto_register_subtree_array(ett, array_length(ett));
+
+ register_capture_dissector("isl", capture_isl, proto_isl);
+}
+
+void
+proto_reg_handoff_isl(void)
+{
+ /*
+ * Get handles for the Ethernet and Token Ring dissectors.
+ */
+ eth_withfcs_handle = find_dissector_add_dependency("eth_withfcs", proto_isl);
+ tr_handle = find_dissector_add_dependency("tr", proto_isl);
+
+ eth_cap_handle = find_capture_dissector("eth");
+ tr_cap_handle = find_capture_dissector("tr");
+}
+
+/*
+ * Editor modelines - https://www.wireshark.org/tools/modelines.html
+ *
+ * Local Variables:
+ * c-basic-offset: 2
+ * tab-width: 8
+ * indent-tabs-mode: nil
+ * End:
+ *
+ * ex: set shiftwidth=2 tabstop=8 expandtab:
+ * :indentSize=2:tabSize=8:noTabs=true:
+ */
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