Wireshark · Ethereal-dev: [Ethereal-dev] Re: Kismet protocol dissector

["Krzysztof Burghardt" <krzysztof@xxxxxxxxxxxx>]

Thanks for your reply.

> 1, please create a WIKI page on wiki.wireshark.org for this protocol.

Done, see it here:
http://wiki.wireshark.org/Kismet_Client/Server_Protocol
http://wiki.ethereal.com/Kismet_Client/Server_Protocol

> 2, upload the example traces to that wiki page.

done

> 3, you use "hidden" fields such as the hf_kismet_[request|response]
> Hidden fields are in general a bad idea since it prevents the user
> from knowing about them.

Changed to "generated" fields.

> 4, you usae tvb_get_string   whis requires the data to ge g_free()d

Changed to use tvb_get_ephemeral_string().

> 5,   is it possible to change the dissector to be a new style
> dissector   returning gboolean instead of an oldstyle returning void?

Here is a (small) problem. I changed dissector, so it use gboolean and
always return true, but I have no idea how to check if it is kismet or
not. Some suggestions?

> please address these issues and resubmit the patch to the mailinglist
> for rereview.

Patch attached.

Regards,
-- 
Krzysztof Burghardt <krzysztof@xxxxxxxxxxxx>
http://www.burghardt.pl/

Index: epan/dissectors/packet-kismet.c
===================================================================
--- epan/dissectors/packet-kismet.c	(revision 0)
+++ epan/dissectors/packet-kismet.c	(revision 0)
@@ -0,0 +1,283 @@
+/* packet-kismet.c
+ * Routines for kismet packet dissection
+ * Copyright 2006, Krzysztof Burghardt <krzysztof@xxxxxxxxxxxx>
+ *
+ * $Id$
+ *
+ * Ethereal - Network traffic analyzer
+ * By Gerald Combs <gerald@xxxxxxxxxxxx>
+ * Copyright 1998 Gerald Combs
+ *
+ * Copied from packet-pop.c
+ *
+ * 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.
+ */
+
+#ifdef HAVE_CONFIG_H
+# include "config.h"
+#endif
+
+#include <stdio.h>
+
+#include <string.h>
+#include <glib.h>
+#include <epan/packet.h>
+#include <epan/strutil.h>
+
+static int proto_kismet = -1;
+static int hf_kismet_response = -1;
+static int hf_kismet_request = -1;
+
+static gint ett_kismet = -1;
+static gint ett_kismet_reqresp = -1;
+
+static dissector_handle_t data_handle;
+
+#define TCP_PORT_KISMET	2501
+
+static gboolean response_is_continuation (const guchar * data);
+
+static gboolean
+dissect_kismet (tvbuff_t * tvb, packet_info * pinfo, proto_tree * tree)
+{
+  gboolean is_request;
+  gboolean is_continuation;
+  proto_tree *kismet_tree, *reqresp_tree;
+  proto_item *ti;
+  proto_item *tmp_item;
+  gint offset = 0;
+  const guchar *line;
+  gint next_offset;
+  int linelen;
+  int tokenlen;
+  const guchar *next_token;
+
+  if (check_col (pinfo->cinfo, COL_PROTOCOL))
+    col_set_str (pinfo->cinfo, COL_PROTOCOL, "kismet");
+
+  /*
+   * Find the end of the first line.
+   *
+   * Note that "tvb_find_line_end()" will return a value that is
+   * not longer than what's in the buffer, so the "tvb_get_ptr()"
+   * call won't throw an exception.
+   */
+  linelen = tvb_find_line_end (tvb, offset, -1, &next_offset, FALSE);
+  line = tvb_get_ptr (tvb, offset, linelen);
+
+  if (pinfo->match_port == pinfo->destport)
+    {
+      is_request = TRUE;
+      is_continuation = FALSE;
+    }
+  else
+    {
+      is_request = FALSE;
+      is_continuation = response_is_continuation (line);
+    }
+
+  if (check_col (pinfo->cinfo, COL_INFO))
+    {
+      /*
+       * Put the first line from the buffer into the summary
+       * if it's a kismet request or reply (but leave out the
+       * line terminator).
+       * Otherwise, just call it a continuation.
+       */
+      if (is_continuation)
+	col_set_str (pinfo->cinfo, COL_INFO, "Continuation");
+      else
+	col_add_fstr (pinfo->cinfo, COL_INFO, "%s: %s",
+		      is_request ? "Request" : "Response",
+		      format_text (line, linelen));
+    }
+
+  if (tree)
+    {
+      ti = proto_tree_add_item (tree, proto_kismet, tvb, offset, -1, FALSE);
+      kismet_tree = proto_item_add_subtree (ti, ett_kismet);
+
+      if (is_continuation)
+	{
+	  /*
+	   * Put the whole packet into the tree as data.
+	   */
+	  call_dissector (data_handle, tvb, pinfo, kismet_tree);
+	  return;
+	}
+
+      if (is_request)
+	{
+	  tmp_item = proto_tree_add_boolean (kismet_tree,
+					 hf_kismet_request, tvb, 0, 0, TRUE);
+	}
+      else
+	{
+	  tmp_item = proto_tree_add_boolean (kismet_tree,
+					 hf_kismet_response, tvb, 0, 0, TRUE);
+	}
+      PROTO_ITEM_SET_GENERATED(tmp_item);
+
+      while (tvb_offset_exists (tvb, offset))
+	{
+	  /*
+	   * Find the end of the line.
+	   */
+	  linelen = tvb_find_line_end (tvb, offset, -1, &next_offset, FALSE);
+
+	  if (linelen)
+	    {
+	      /*
+	       * Put this line.
+	       */
+	      ti = proto_tree_add_text (kismet_tree, tvb, offset,
+					next_offset - offset, "%s",
+					tvb_format_text (tvb, offset,
+							 next_offset -
+							 offset - 1));
+	      reqresp_tree = proto_item_add_subtree (ti, ett_kismet_reqresp);
+	      tokenlen = get_token_len (line, line + linelen, &next_token);
+	      if (tokenlen != 0)
+		{
+		  guint8 *reqresp;
+		  reqresp = tvb_get_ephemeral_string (tvb, offset, tokenlen);
+		  if (is_request)
+		    {
+			/*
+			 * No request dissection
+			 */
+		    }
+		  else
+		    {
+		      /*
+		       * *KISMET: {Version} {Start time} \001{Server name}\001 {Build Revision}
+		       * two fields left undocumented: {1} {ExtendedVersion}
+		       */
+		      if (strncmp (reqresp, "*KISMET", strlen ("*KISMET")) == 0)
+			{
+			  offset += next_token - line; linelen -= next_token - line; line = next_token;
+			  tokenlen = get_token_len (line, line + linelen, &next_token);
+			  proto_tree_add_text (reqresp_tree, tvb, offset,
+					       tokenlen, "Kismet version: %s",
+					       format_text (line, tokenlen));
+			  offset += next_token - line; linelen -= next_token - line; line = next_token;
+			  tokenlen = get_token_len (line, line + linelen, &next_token);
+			  proto_tree_add_text (reqresp_tree, tvb, offset,
+					       tokenlen, "Start time: %s",
+					       format_text (line, tokenlen));
+			  offset += next_token - line; linelen -= next_token - line; line = next_token;
+			  tokenlen = get_token_len (line, line + linelen, &next_token);
+			  proto_tree_add_text (reqresp_tree, tvb, offset,
+					       tokenlen, "Server name: %s",
+					       format_text (line + 1, tokenlen - 2));
+			  offset += next_token - line; linelen -= next_token - line; line = next_token;
+			  tokenlen = get_token_len (line, line + linelen, &next_token);
+			  proto_tree_add_text (reqresp_tree, tvb, offset,
+					       tokenlen, "Build revision: %s",
+					       format_text (line, tokenlen));
+			  offset += next_token - line; linelen -= next_token - line; line = next_token;
+			  tokenlen = get_token_len (line, line + linelen, &next_token);
+			  offset += next_token - line; linelen -= next_token - line; line = next_token;
+			  tokenlen = get_token_len (line, line + linelen, &next_token);
+			  proto_tree_add_text (reqresp_tree, tvb, offset,
+						tokenlen, "Extended version string: %s",
+						format_text (line, tokenlen));
+			}
+		      /*
+		       * *TIME: {Time}
+		       */
+		      if (strncmp (reqresp, "*TIME", strlen ("*TIME")) == 0)
+			{
+			  time_t t;
+			  char *ptr;
+
+			  offset += next_token - line; linelen -= next_token - line; line = next_token;
+			  tokenlen = get_token_len (line, line + linelen, &next_token);
+
+			  /*
+			   * Convert form ascii to time_t
+			   */
+			  t = atoi (format_text (line, tokenlen));
+			  
+			  /*
+			   * Format ascii representation of time
+			   */
+			  ptr = ctime (&t);
+			  /*
+			   * Delete final '\n'
+			   */
+			  ptr[strlen(ptr) - 1] = 0;
+
+			  proto_tree_add_text (reqresp_tree, tvb, offset,
+						tokenlen, "Time: %s", ptr);
+			}
+		    }
+		  offset += next_token - line; linelen -= next_token - line; line = next_token;
+		}
+	    }
+	  offset = next_offset;
+	}
+    }
+  return TRUE;
+}
+
+static gboolean
+response_is_continuation (const guchar * data)
+{
+  if (strncmp (data, "*", strlen ("*")) == 0)
+    return FALSE;
+
+  if (strncmp (data, "!", strlen ("!")) == 0)
+    return FALSE;
+
+  return TRUE;
+}
+
+void
+proto_register_kismet (void)
+{
+
+  static hf_register_info hf[] = {
+    {&hf_kismet_response,
+     {"Response", "kismet.response",
+      FT_BOOLEAN, BASE_NONE, NULL, 0x0,
+      "TRUE if kismet response", HFILL}},
+
+    {&hf_kismet_request,
+     {"Request", "kismet.request",
+      FT_BOOLEAN, BASE_NONE, NULL, 0x0,
+      "TRUE if kismet request", HFILL}}
+  };
+  static gint *ett[] = {
+    &ett_kismet,
+    &ett_kismet_reqresp,
+  };
+
+  proto_kismet =
+    proto_register_protocol ("Kismet Client/Server Protocol", "kismet",
+			     "kismet");
+  proto_register_field_array (proto_kismet, hf, array_length (hf));
+  proto_register_subtree_array (ett, array_length (ett));
+}
+
+void
+proto_reg_handoff_kismet (void)
+{
+  dissector_handle_t kismet_handle;
+
+  kismet_handle = create_dissector_handle (dissect_kismet, proto_kismet);
+  dissector_add ("tcp.port", TCP_PORT_KISMET, kismet_handle);
+  data_handle = find_dissector ("data");
+}
Index: epan/dissectors/Makefile.common
===================================================================
--- epan/dissectors/Makefile.common	(revision 18189)
+++ epan/dissectors/Makefile.common	(working copy)
@@ -394,6 +394,7 @@
 	packet-kerberos4.c	\
 	packet-klm.c	\
 	packet-kink.c	\
+	packet-kismet.c	\
 	packet-kpasswd.c	\
 	packet-l2tp.c	\
 	packet-lapb.c	\

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