Wireshark · Ethereal-dev: [Ethereal-dev] [PATCH] dissect tivoconnect beacons

[Kees Cook <kees@xxxxxxxxxxx>]

Hello!  I've read through all the developer documentation and wiki items 
on making dissectors and submitting patches, so I hope I haven't left 
anything out.  Attached is a dissector for "TiVoConnect Beacon" traffic, 
along with a capture file showing both tcd and pc examples.  I've run 
this through fuzz-test, and didn't hit any problems.

Please let me know if there is anything I can do to improve this patch.

Thanks!

-- 
Kees Cook                                            @outflux.net

Index: epan/dissectors/Makefile.common
===================================================================
--- epan/dissectors/Makefile.common	(revision 18189)
+++ epan/dissectors/Makefile.common	(working copy)
@@ -617,6 +617,7 @@
 	packet-tftp.c	\
 	packet-time.c	\
 	packet-tipc.c	\
+	packet-tivoconnect.c	\
 	packet-tns.c	\
 	packet-tpkt.c	\
 	packet-tr.c	\
Index: epan/dissectors/packet-tivoconnect.c
===================================================================
--- epan/dissectors/packet-tivoconnect.c	(revision 0)
+++ epan/dissectors/packet-tivoconnect.c	(revision 0)
@@ -0,0 +1,278 @@
+/* packet-tivoconnect.c
+ * Routines for TiVoConnect Discovery Protocol dissection
+ * Copyright 2006, Kees Cook <kees@xxxxxxxxxxx>
+ * IANA UDP/TCP port: 2190 (tivoconnect)
+ * Protocol Spec: http://tivo.com/developer/i/TiVoConnectDiscovery.pdf
+ *
+ * IANA's full name is "TiVoConnect Beacon", where as TiVo's own
+ * documentation calls this protocol "TiVoConnect Discovery Protocol".
+ *
+ * $Id: README.developer 18163 2006-05-15 16:28:49Z kukosa $
+ *
+ * Ethereal - Network traffic analyzer
+ * By Gerald Combs <gerald@xxxxxxxxxxxx>
+ * Copyright 1998 Gerald Combs
+ *
+ * Copied from README.developer
+ * 
+ * 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.
+ */
+
+/*
+ * TODO
+ * - split services into a subtree
+ * - split platform into a subtree
+ *
+ */
+
+#ifdef HAVE_CONFIG_H
+# include "config.h"
+#endif
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include <glib.h>
+
+#include <epan/packet.h>
+#include <epan/prefs.h>
+#include <epan/ipproto.h>
+
+/* Forward declaration we need below */
+void proto_reg_handoff_tivoconnect(void);
+
+/* Initialize the protocol and registered fields */
+static int proto_tivoconnect = -1;
+static int hf_tivoconnect_flavor = -1;
+static int hf_tivoconnect_method = -1;
+static int hf_tivoconnect_platform = -1;
+static int hf_tivoconnect_machine = -1;
+static int hf_tivoconnect_identity = -1;
+static int hf_tivoconnect_services = -1;
+static int hf_tivoconnect_version = -1;
+
+/* Initialize the subtree pointers */
+static gint ett_tivoconnect = -1;
+
+/* Code to actually dissect the packets */
+static gboolean
+dissect_tivoconnect(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
+{
+    /* parsing variables */
+    gchar * string = NULL;
+    gint length = -1;
+    /* value strings */
+    gchar * proto_name = NULL;
+    gchar * packet_identity = NULL;
+    gchar * packet_machine = NULL;
+
+    /* validate that we have a tivoconnect packet */
+    length = tvb->length;
+    if ( length < 11 ||
+         !(string = (gchar*)tvb_get_ephemeral_string(tvb, 0, length)) ||
+         strncasecmp(string,"tivoconnect",11) != 0) {
+        return FALSE;
+    }
+
+    /* Make entries in Protocol column and Info column on summary display */
+    if (check_col(pinfo->cinfo, COL_PROTOCOL)) 
+        col_set_str(pinfo->cinfo, COL_PROTOCOL, "TiVoConnect");
+    
+    /* make a distinction between UDP and TCP packets */
+    proto_name = pinfo->ipproto == IP_PROTO_TCP ?
+                    "Discovery Connection" :
+                    "Discovery Beacon";
+
+    if (check_col(pinfo->cinfo, COL_INFO)) 
+        col_set_str(pinfo->cinfo, COL_INFO, proto_name);
+
+    if (tree) {
+        /* Set up structures needed to add the protocol subtree and manage it */
+        proto_item *ti = NULL;
+        proto_tree *tivoconnect_tree = NULL;
+
+        /* parsing variables */
+        guint offset = 0;
+        gchar * field = NULL;
+
+        /* create display subtree for the protocol */
+        ti = proto_tree_add_item(tree, proto_tivoconnect, tvb, 0, -1, FALSE);
+
+        tivoconnect_tree = proto_item_add_subtree(ti, ett_tivoconnect);
+
+        /* process the packet */
+        for ( field = strtok(string,"\n");
+              field;
+              offset+=length, field = strtok(NULL,"\n") ) {
+            gchar * value = NULL;
+            gint fieldlen;
+
+            length = strlen(field) + 1;
+
+            if ( !(value=strchr(field, '=')) ) {
+                /* bad packet: missing the field separator */
+                continue;
+            }
+            *value++='\0';
+            fieldlen=strlen(field)+1;
+
+            if ( strcasecmp(field,"tivoconnect") == 0 ) {
+                proto_tree_add_item(tivoconnect_tree,
+                    hf_tivoconnect_flavor, tvb, offset+fieldlen,
+                    length-fieldlen-1, FALSE);
+            }
+            else if ( strcasecmp(field,"method") == 0 ) {
+                proto_tree_add_item(tivoconnect_tree,
+                    hf_tivoconnect_method, tvb, offset+fieldlen,
+                    length-fieldlen-1, FALSE);
+            }
+            else if ( strcasecmp(field,"platform") == 0 ) {
+                proto_tree_add_item(tivoconnect_tree,
+                    hf_tivoconnect_platform, tvb, offset+fieldlen,
+                    length-fieldlen-1, FALSE);
+            }
+            else if ( strcasecmp(field,"machine") == 0 ) {
+                proto_tree_add_item(tivoconnect_tree,
+                    hf_tivoconnect_machine, tvb, offset+fieldlen,
+                    length-fieldlen-1, FALSE);
+                packet_machine = value;
+            }
+            else if ( strcasecmp(field,"identity") == 0 ) {
+                proto_tree_add_item(tivoconnect_tree,
+                    hf_tivoconnect_identity, tvb, offset+fieldlen,
+                    length-fieldlen-1, FALSE);
+                packet_identity = value;
+            }
+            else if ( strcasecmp(field,"services") == 0 ) {
+                proto_tree_add_item(tivoconnect_tree,
+                    hf_tivoconnect_services, tvb, offset+fieldlen,
+                    length-fieldlen-1, FALSE);
+            }
+            else if ( strcasecmp(field,"swversion") == 0 ) {
+                proto_tree_add_item(tivoconnect_tree,
+                    hf_tivoconnect_version, tvb, offset+fieldlen,
+                    length-fieldlen-1, FALSE);
+            }
+            else {
+                /* unknown field! */
+            }
+        }
+
+        /* Adjust "Info" column and top of tree into more useful info */
+        if (packet_machine) {
+            proto_item_append_text(ti, ", %s", packet_machine);
+            if (check_col(pinfo->cinfo, COL_INFO)) 
+                col_add_fstr(pinfo->cinfo, COL_INFO, "%s %s",
+                                            proto_name, packet_machine);
+        }
+        if (packet_identity) {
+            proto_item_append_text(ti,
+                        packet_machine ? " (%s)" : ", ID:%s",
+                        packet_identity);
+            if (packet_machine) {
+                if (check_col(pinfo->cinfo, COL_INFO)) 
+                    col_add_fstr(pinfo->cinfo, COL_INFO, "%s %s (%s)",
+                                 proto_name, packet_machine, packet_identity);
+            }
+            else {
+                if (check_col(pinfo->cinfo, COL_INFO)) 
+                    col_add_fstr(pinfo->cinfo, COL_INFO, "%s ID:%s",
+                                 proto_name, packet_identity);
+            }
+        }
+
+    }
+
+    /* If this protocol has a sub-dissector call it here, see section 1.8 */
+
+    return TRUE;
+}
+
+
+/* Register the protocol with Ethereal */
+
+/* this format is require because a script is used to build the C function
+   that calls all the protocol registration.
+*/
+
+void
+proto_register_tivoconnect(void)
+{                 
+    /* Setup list of header fields  See Section 1.6.1 for details*/
+    static hf_register_info hf[] = {
+        { &hf_tivoconnect_flavor,
+            { "Flavor",           "tivoconnect.flavor",
+            FT_STRINGZ, BASE_NONE, NULL, 0,          
+            "Protocol Flavor supported by the originator", HFILL }},
+        { &hf_tivoconnect_method,
+            { "Method",           "tivoconnect.method",
+            FT_STRINGZ, BASE_NONE, NULL, 0,          
+            "Packet was delivered via UDP(broadcast) or TCP(connected)", HFILL }},
+        { &hf_tivoconnect_platform,
+            { "Platform",           "tivoconnect.platform",
+            FT_STRINGZ, BASE_NONE, NULL, 0,          
+            "System platform, either tcd(TiVo) or pc(Computer)", HFILL }},
+        { &hf_tivoconnect_machine,
+            { "Machine",           "tivoconnect.machine",
+            FT_STRINGZ, BASE_NONE, NULL, 0,          
+            "Human-readable system name", HFILL }},
+        { &hf_tivoconnect_identity,
+            { "Identity",           "tivoconnect.identity",
+            FT_STRINGZ, BASE_NONE, NULL, 0,          
+            "Unique serial number for the system", HFILL }},
+        { &hf_tivoconnect_services,
+            { "Services",           "tivoconnect.services",
+            FT_STRINGZ, BASE_NONE, NULL, 0,          
+            "List of available services on the system", HFILL }},
+        { &hf_tivoconnect_version,
+            { "Version",           "tivoconnect.version",
+            FT_STRINGZ, BASE_NONE, NULL, 0,          
+            "System software version", HFILL }},
+    };
+
+    /* Setup protocol subtree array */
+    static gint *ett[] = {
+        &ett_tivoconnect,
+    };
+
+    /* Register the protocol name and description */
+    proto_tivoconnect = proto_register_protocol("TiVoConnect Discovery Protocol",
+        "TiVoConnect", "tivoconnect");
+
+    /* Required function calls to register the header fields and subtrees used */
+    proto_register_field_array(proto_tivoconnect, hf, array_length(hf));
+    proto_register_subtree_array(ett, array_length(ett));
+}
+
+
+void
+proto_reg_handoff_tivoconnect(void)
+{
+        static gboolean inited = FALSE;
+        
+        if( !inited ) {
+
+            dissector_handle_t tivoconnect_handle;
+
+            tivoconnect_handle = create_dissector_handle(dissect_tivoconnect,
+                                                         proto_tivoconnect);
+            dissector_add("udp.port", 2190, tivoconnect_handle);
+            dissector_add("tcp.port", 2190, tivoconnect_handle);
+        
+            inited = TRUE;
+        }
+}
+

Attachment: sample-tivoconnect.pcap
Description: Binary data

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