New dissector for the cisco wireless ids communication protocol

(name invented by me, better suggenstions welcome).

svn path=/trunk/; revision=18671

1 files changed, 198 insertions, 0 deletions

diff --git a/epan/dissectors/packet-cisco-wids.c b/epan/dissectors/packet-cisco-wids.c
new file mode 100644
index 0000000000..1ab5caf9ed
--- /dev/null
+++ b/epan/dissectors/packet-cisco-wids.c
@@ -0,0 +1,198 @@
+/* packet-cwids.c
+ * Routines for dissecting wireless ids packets sent from a Cisco 
+ * access point to the WLSE (or whatever)
+ *
+ * $Id$
+ *
+ * Copyright 2006 Joerg Mayer (see AUTHORS file)
+ *
+ * Wireshark - Network traffic analyzer
+ * By Gerald Combs <gerald@wireshark.org>
+ * Copyright 1998 Gerald Combs
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
+ */
+
+/* With current IOS, you can use Cisco wireless Bridges/APs as a
+ * wireless sniffers and configure them with the "monitor ..."
+ * command to * send the data to some central IDS.
+ * This dissector tries to decode those frames.
+ */
+
+/* 2do:
+ *	- Find out more about the contents of the capture header
+ *	- Protect the address fields etc (all columns?)
+ *	- Create subelements and put each header and packet into it
+ *	- fuzz-test the dissector
+ *	- Find some heuristic do detect the packet automagically and
+ *	  convert dissector into a heuristic dissector
+ *	- Is the TRY/CATCH stuff OK?
+ */
+
+#ifdef HAVE_CONFIG_H
+# include "config.h"
+#endif
+
+#include <glib.h>
+#include <epan/packet.h>
+#include <epan/etypes.h>
+#include <epan/expert.h>
+#include <epan/prefs.h>
+
+static guint udp_port = 0;
+void proto_reg_handoff_cwids(void);
+
+
+static int proto_cwids = -1;
+static int hf_cwids_version = -1;
+static int hf_cwids_unknown1 = -1;
+static int hf_cwids_reallength = -1;
+static int hf_cwids_capturelen = -1;
+static int hf_cwids_unknown2 = -1;
+static int hf_cwids_trailer = -1;
+
+static gint ett_cwids = -1;
+
+static dissector_handle_t ieee80211_handle;
+
+static void
+dissect_cwids(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
+{
+	tvbuff_t *wlan_tvb;
+	proto_tree *ti, *cwids_tree;
+	int offset = 0;
+	guint16 capturelen;
+	guint remain;
+
+	if (check_col(pinfo->cinfo, COL_PROTOCOL))
+	  col_set_str(pinfo->cinfo, COL_PROTOCOL, "CWIDS");
+	if (check_col(pinfo->cinfo, COL_INFO))
+	  col_clear(pinfo->cinfo, COL_INFO);
+
+	if (check_col(pinfo->cinfo, COL_INFO)) {
+	  col_add_fstr(pinfo->cinfo, COL_INFO, "Cwids: ");
+	}
+	/* FIXME: col_set_fence(pinfo->cinfo, all-cols, only addr-cols?); */
+
+	cwids_tree = NULL;
+
+	while((remain = tvb_length_remaining(tvb, offset)) >= 28) {
+		ti = proto_tree_add_item(tree, proto_cwids, tvb, offset, 28, FALSE);
+		cwids_tree = proto_item_add_subtree(ti, ett_cwids);
+	
+		proto_tree_add_item(cwids_tree, hf_cwids_version, tvb, offset, 2, FALSE);
+		offset += 2;
+		proto_tree_add_item(cwids_tree, hf_cwids_unknown1, tvb, offset, 14, FALSE);
+		offset += 14;
+		proto_tree_add_item(cwids_tree, hf_cwids_reallength, tvb, offset, 2, FALSE);
+		offset += 2;
+		capturelen = tvb_get_ntohs(tvb, offset);
+		proto_tree_add_item(cwids_tree, hf_cwids_capturelen, tvb, offset, 2, FALSE);
+		offset += 2;
+		proto_tree_add_item(cwids_tree, hf_cwids_unknown2, tvb, offset, 8, FALSE);
+		offset += 8;
+	
+		wlan_tvb = tvb_new_subset(tvb, offset, capturelen, capturelen);
+		/* Continue after ieee80211 dissection errors */
+		TRY {
+			call_dissector(ieee80211_handle, wlan_tvb, pinfo, tree);
+		} CATCH2(BoundsError, ReportedBoundsError) {
+
+			expert_add_info_format(pinfo, NULL,
+				PI_MALFORMED, PI_ERROR,
+				"Malformed or short IEEE80211 subpacket");
+
+			if (check_col(pinfo->cinfo, COL_INFO)) {
+				col_append_str(pinfo->cinfo, COL_INFO,
+					" [Malformed or short IEEE80211 subpacket] " );
+				col_set_fence(pinfo->cinfo, COL_INFO);
+			}
+
+	wlan_tvb = tvb_new_subset(tvb, offset, capturelen, capturelen);
+#if 0
+			/* FIXME: Why does this throw an exception? */
+			proto_tree_add_text(cwids_tree, wlan_tvb, offset, capturelen, 
+				"[Malformed or short IEEE80211 subpacket]");
+#endif
+	;
+		} ENDTRY;
+
+		offset += capturelen;
+	}
+	if (remain > 0) { /* FIXME: Shouldn't happen? */
+		ti = proto_tree_add_item(tree, proto_cwids, tvb, offset, remain, FALSE);
+		cwids_tree = proto_item_add_subtree(ti, ett_cwids);
+
+		proto_tree_add_item(cwids_tree, hf_cwids_trailer, tvb, offset, remain, FALSE);
+	}
+}
+
+void
+proto_register_cwids(void)
+{
+	static hf_register_info hf[] = {
+		{ &hf_cwids_version,
+		{ "Capture Version", "cwids.version", FT_UINT16, BASE_DEC, NULL,
+			0x0, "Version or format of record", HFILL }},
+
+		{ &hf_cwids_unknown1,
+		{ "Unknown1", "cwids.unknown1", FT_BYTES, BASE_NONE, NULL,
+			0x0, "1st Unknown block", HFILL }},
+
+		{ &hf_cwids_reallength,
+		{ "Original length", "cwids.reallen", FT_UINT16, BASE_DEC, NULL,
+			0x0, "Original num bytes in frame", HFILL }},
+
+		{ &hf_cwids_capturelen,
+		{ "Capture length", "cwids.caplen", FT_UINT16, BASE_DEC, NULL,
+			0x0, "Captured bytes in record", HFILL }},
+
+		{ &hf_cwids_unknown2,
+		{ "Unknown2", "cwids.unknown2", FT_BYTES, BASE_NONE, NULL,
+			0x0, "2nd Unknown block", HFILL }},
+
+		{ &hf_cwids_trailer,
+		{ "Trailer", "cwids.trailer", FT_BYTES, BASE_NONE, NULL,
+			0x0, "CWIDS trailer", HFILL }},
+	};
+	static gint *ett[] = {
+		&ett_cwids,
+	};
+
+	module_t *cwids_module;
+
+	proto_cwids = proto_register_protocol("Cisco Wireless IDS Captures", "CWIDS", "cwids");
+	proto_register_field_array(proto_cwids, hf, array_length(hf));
+	proto_register_subtree_array(ett, array_length(ett));
+
+	cwids_module = prefs_register_protocol(proto_cwids, proto_reg_handoff_cwids);
+	prefs_register_uint_preference(cwids_module, "udp.port",
+		"CWIDS port",
+		"Set the destination UDP port Cisco wireless IDS messages",
+		10, &udp_port);
+
+}
+
+void
+proto_reg_handoff_cwids(void)
+{
+	dissector_handle_t cwids_handle;
+
+	ieee80211_handle = find_dissector("wlan");
+
+	cwids_handle = create_dissector_handle(dissect_cwids, proto_cwids);
+	dissector_add("udp.port", udp_port, cwids_handle);
+}
+