/* packet-bananna.c
 * Routines for the Twisted Banana serialization protocol dissection
 * Copyright 2009, Gerald Combs <gerald@wireshark.org>
 *
 * $Id: packet-banana.c 28971 2009-07-07 09:02:59Z stig $
 *
 * 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., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
 */

/*
 * Based on "Banana Protocol Specifications"
 * http://twistedmatrix.com/projects/core/documentation/specifications/banana.html
 */

#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/expert.h>

/* Initialize the protocol and registered fields */
static int proto_banana = -1;
static int hf_banana_list = -1;
static int hf_banana_int = -1;
static int hf_banana_string = -1;
static int hf_banana_neg_int = -1;
static int hf_banana_float = -1;
static int hf_banana_lg_int = -1;
static int hf_banana_lg_neg_int = -1;
static int hf_banana_pb = -1;

/* Initialize the subtree pointers */
static gint ett_banana = -1;
static gint ett_list = -1;

dissector_handle_t banana_handle;

#define BE_LIST			0x80
#define BE_INT			0x81
#define BE_STRING		0x82
#define BE_NEG_INT		0x83
#define BE_FLOAT		0x84
#define BE_LG_INT		0x85
#define BE_LG_NEG_INT	0x86
#define BE_PB			0x87

#define is_element(b) (b >= BE_LIST && b <= BE_PB)

static const value_string type_vals[] = {
	{ BE_LIST,			"List" },
	{ BE_INT,			"Integer" },
	{ BE_STRING,		"String" },
	{ BE_NEG_INT,		"Negative Integer" },
	{ BE_FLOAT,			"Float" },
	{ BE_LG_INT,		"Large Integer" },
	{ BE_LG_NEG_INT,	"Large Negative Integer" },
	{ BE_PB,			"pb Profile"},
	{ 0, NULL }
};

static const value_string pb_vals[] = {
	{ 0x01,	"None" },
	{ 0x02,	"class" },
	{ 0x03,	"dereference" },
	{ 0x04,	"reference" },
	{ 0x05,	"dictionary" },
	{ 0x06,	"function" },
	{ 0x07,	"instance" },
	{ 0x08,	"list" },
	{ 0x09,	"module" },
	{ 0x0a,	"persistent" },
	{ 0x0b,	"tuple" },
	{ 0x0c,	"unpersistable" },
	{ 0x0d,	"copy" },
	{ 0x0e,	"cache" },
	{ 0x0f,	"cached" },
	{ 0x10,	"remote" },
	{ 0x11,	"local" },
	{ 0x12,	"lcache" },
	{ 0x13,	"version" },
	{ 0x14,	"login" },
	{ 0x15,	"password" },
	{ 0x16,	"challenge" },
	{ 0x17,	"logged_in" },
	{ 0x18,	"not_logged_in" },
	{ 0x19,	"cachemessage" },
	{ 0x1a,	"message" },
	{ 0x1b,	"answer" },
	{ 0x1c,	"error" },
	{ 0x1d,	"decref" },
	{ 0x1e,	"decache" },
	{ 0x1f,	"uncache" },
	{ 0,	NULL }
};

#define MAX_ELEMENT_VAL 2147483647 /* Max TE value */
#define MAX_ELEMENT_INT_LEN 4
#define MAX_ELEMENT_VAL_LEN 8 

static range_t *global_banana_tcp_range = NULL;
static range_t *banana_tcp_range = NULL;

/* Dissect the packets */

static int
dissect_banana_element(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, int offset) {
	proto_item *ti;
	proto_tree *list_tree;
	guint8 byte = 0;
	gint64 val = 0;
	gint val_len = 0;
	int start_offset = offset;
	int old_offset;
	int i;
	
	/* Accumulate our value/length 'til we hit a valid type */
	while (tvb_length_remaining(tvb, offset) > 0) {
		byte = tvb_get_guint8(tvb, offset);
		offset++;
	
		if (byte & 0x80) {
			if (is_element(byte)) {
				break;
			} else {
				expert_add_info_format(pinfo, NULL, PI_UNDECODED, PI_ERROR, "Unknown type %u", byte);
			}
		} else {
			val_len++;
			if (val_len > MAX_ELEMENT_VAL_LEN) {
				expert_add_info_format(pinfo, NULL, PI_UNDECODED, PI_ERROR, "Too many value/length bytes");
			}
			val += byte + (val << 7);
		}
	}

	/* Type */
	switch (byte) {
		case BE_LIST:
			if (val > MAX_ELEMENT_VAL) {
				expert_add_info_format(pinfo, NULL, PI_UNDECODED, PI_ERROR, "List length %" G_GINT64_MODIFIER "d longer than we can handle", val);
			}
			ti = proto_tree_add_uint_format_value(tree, hf_banana_list, tvb, start_offset, offset - start_offset - 1, (guint32) val, "(%d items)", (gint) val);
			list_tree = proto_item_add_subtree(ti, ett_list);
			for (i = 0; i < val; i++) {
				old_offset = offset;
				offset += dissect_banana_element(tvb, pinfo, list_tree, offset);
				if (offset <= old_offset) {
					return offset - start_offset;
				}
			}
			break;
		case BE_INT:
			if (val > MAX_ELEMENT_VAL) {
				expert_add_info_format(pinfo, NULL, PI_MALFORMED, PI_ERROR, "Integer value %" G_GINT64_MODIFIER "d too large", val);
			}
			proto_tree_add_uint(tree, hf_banana_int, tvb, start_offset, offset - start_offset, (guint32) val);
			break;
		case BE_STRING:
			if (val > MAX_ELEMENT_VAL) {
				expert_add_info_format(pinfo, NULL, PI_UNDECODED, PI_ERROR, "String length %" G_GINT64_MODIFIER "d longer than we can handle", val);
			}
			proto_tree_add_item(tree, hf_banana_string, tvb, offset, (guint32) val, FALSE);
			offset += (gint) val;
			break;
		case BE_NEG_INT:
			if (val > MAX_ELEMENT_VAL) {
				expert_add_info_format(pinfo, NULL, PI_MALFORMED, PI_ERROR, "Integer value -%" G_GINT64_MODIFIER "d too large", val);
			}
			proto_tree_add_int(tree, hf_banana_neg_int, tvb, start_offset, offset - start_offset, (gint32) val * -1);
			break;
		case BE_FLOAT:
			proto_tree_add_item(tree, hf_banana_float, tvb, offset, 8, FALSE);
			offset += 8;
			break;
		case BE_LG_INT:
			proto_tree_add_item(tree, hf_banana_lg_int, tvb, start_offset, offset - start_offset, FALSE);
			break;
		case BE_LG_NEG_INT:
			proto_tree_add_item(tree, hf_banana_lg_neg_int, tvb, start_offset, offset - start_offset, FALSE);
			break;
		case BE_PB:
			if (val_len > 1) {
				expert_add_info_format(pinfo, NULL, PI_MALFORMED, PI_ERROR, "More than 1 byte before pb");
			}
			/*
			 * The spec says the pb dictionary value comes after the tag.
			 * In real-world captures it comes before.
			 */
			proto_tree_add_item(tree, hf_banana_pb, tvb, offset - 2, 1, FALSE);
			break;
		default:
			return 0;
			break;
	}
	return offset - start_offset;
}

static int
dissect_banana(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree) {
	guint8 byte = 0;
	gint offset = 0, old_offset;
	proto_item *ti;
	proto_tree *banana_tree;

	/* Check that there's enough data */
	if (tvb_length(tvb) < 2)
		return 0;

	/* Fill in our protocol and info columns */
	col_set_str(pinfo->cinfo, COL_PROTOCOL, "Banana");

	while (tvb_length_remaining(tvb, offset) > 0 && offset < MAX_ELEMENT_VAL_LEN) {
		byte = tvb_get_guint8(tvb, offset);
		if (is_element(byte))
			break;
		offset++;
	}
	col_add_fstr(pinfo->cinfo, COL_INFO, "First element: %s",
		val_to_str(byte, type_vals, "Unknown type: %u"));

	if (tree) {
		/* Create display subtree for the protocol */
		ti = proto_tree_add_item(tree, proto_banana, tvb, 0, -1, FALSE);
		banana_tree = proto_item_add_subtree(ti, ett_banana);

		offset = 0;
		old_offset = -1;
		while (offset > old_offset) {
			old_offset = offset;
			offset += dissect_banana_element(tvb, pinfo, banana_tree, offset);
		}
	}

	/* Return the amount of data this dissector was able to dissect */
	return tvb_length(tvb);
}

static void
range_delete_banana_tcp_callback(guint32 port) {
	  dissector_delete("tcp.port", port, banana_handle);
}

static void
range_add_banana_tcp_callback(guint32 port) {
	dissector_add("tcp.port", port, banana_handle);
}

static void
banana_prefs(void) {
	range_foreach(banana_tcp_range, range_delete_banana_tcp_callback);
	g_free(banana_tcp_range);
	banana_tcp_range = range_copy(global_banana_tcp_range);
	range_foreach(banana_tcp_range, range_add_banana_tcp_callback);
}

/* Register the protocol with Wireshark */

void
proto_register_banana(void)
{
	static hf_register_info hf[] = {
		{ &hf_banana_list,
			{ "List Length", "banana.list",
				FT_UINT32, BASE_DEC, NULL, 0,
				"Banana list", HFILL }
		},
		{ &hf_banana_int,
			{ "Integer", "banana.int",
				FT_UINT32, BASE_DEC, NULL, 0,
				"Banana integer", HFILL }
		},
		{ &hf_banana_string,
			{ "String", "banana.string",
				FT_STRING, BASE_NONE, NULL, 0,
				"Banana string", HFILL }
		},
		{ &hf_banana_neg_int,
			{ "Negative Integer", "banana.neg_int",
				FT_INT32, BASE_DEC, NULL, 0,
				"Banana negative integer", HFILL }
		},
		{ &hf_banana_float,
			{ "Float", "banana.float",
				FT_DOUBLE, BASE_NONE, NULL, 0,
				"Banana float", HFILL }
		},
		{ &hf_banana_lg_int,
			{ "Float", "banana.lg_int",
				FT_BYTES, BASE_NONE, NULL, 0,
				"Banana large integer", HFILL }
		},
		{ &hf_banana_lg_neg_int,
			{ "Float", "banana.lg_neg_int",
				FT_BYTES, BASE_NONE, NULL, 0,
				"Banana large negative integer", HFILL }
		},
		{ &hf_banana_pb,
			{ "pb Profile Value", "banana.pb",
				FT_UINT8, BASE_HEX, VALS(pb_vals), 0,
				"Banana Perspective Broker Profile Value", HFILL }
		}
	};

	module_t *banana_module;

	/* Setup protocol subtree array */
	static gint *ett[] = {
		&ett_banana,
		&ett_list
	};

	/* Register the protocol name and description */
	proto_banana = proto_register_protocol("Twisted Banana",
		"Banana", "banana");

	/* Required function calls to register the header fields and subtrees used */
	proto_register_field_array(proto_banana, hf, array_length(hf));
	proto_register_subtree_array(ett, array_length(ett));

	/* Initialize dissector preferences */
	banana_module = prefs_register_protocol(proto_banana, banana_prefs);
	banana_tcp_range = range_empty();
	prefs_register_range_preference(banana_module, "tcp.port", "TCP Ports", "Banana TCP Port range", &global_banana_tcp_range, 65535);
}

void
proto_reg_handoff_banana(void)
{
	banana_handle = new_create_dissector_handle(dissect_banana, proto_banana);
}

/*
 * Editor modelines  -  http://www.wireshark.org/tools/modelines.html
 *
 * Local variables:
 * c-basic-offset: 4
 * tab-width: 4
 * indent-tabs-mode: t
 * End:
 *
 * ex: set shiftwidth=4 tabstop=4 noexpandtab
 * :indentSize=4:tabSize=4:noTabs=false:
 */


