dissector branch: added wireshark dissector minetest.lua

1 files changed, 1285 insertions, 0 deletions

diff --git a/util/wireshark/minetest.lua b/util/wireshark/minetest.lua
new file mode 100644
index 000000000..a7cd0c77c
--- /dev/null
+++ b/util/wireshark/minetest.lua
@@ -0,0 +1,1285 @@
+-- minetest.lua
+-- Packet dissector for the UDP-based Minetest protocol
+-- Copy this to $HOME/.wireshark/plugins/
+
+
+--
+-- Minetest-c55
+-- Copyright (C) 2011 celeron55, Perttu Ahola <celeron55@gmail.com>
+--
+-- 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.
+--
+
+
+-- Table of Contents:
+--   Part 1: Client command dissectors (TOSERVER_*)
+--   Part 2: Server command dissectors (TOCLIENT_*)
+--   Part 3: Wrapper protocol subdissectors
+--   Part 4: Wrapper protocol main dissector
+--   Part 5: Utility functions
+
+
+
+
+--------------------------------------------
+-- Part 1                                 --
+-- Client command dissectors (TOSERVER_*) --
+--------------------------------------------
+
+minetest_client_commands = {}
+minetest_client_obsolete = {}
+
+-- TOSERVER_INIT
+
+do
+	local f_ser_fmt = ProtoField.uint8("minetest.client.init_ser_version",
+		"Maximum serialization format version", base.DEC)
+	local f_player_name = ProtoField.stringz("minetest.client.init_player_name", "Player Name")
+	local f_password = ProtoField.stringz("minetest.client.init_password", "Password")
+	local f_version = ProtoField.uint16("minetest.client.init_version", "Version", base.DEC)
+
+	minetest_client_commands[0x10] = {
+		"INIT",                             -- Command name
+		53,                                 -- Minimum message length including code
+		{ f_ser_fmt,                        -- List of fields [optional]
+		  f_player_name,
+		  f_password,
+		  f_version },
+		function(buffer, pinfo, tree, t)    -- Dissector function [optional]
+			t:add(f_ser_fmt, buffer(2,1))
+			t:add(f_player_name, buffer(3,20))
+			t:add(f_password, buffer(23,28))
+			t:add(f_version, buffer(51,2))
+		end
+	}
+end
+
+-- TOSERVER_INIT2
+
+minetest_client_commands[0x11] = { "INIT2", 2 }
+
+-- TOSERVER_GETBLOCK (obsolete)
+
+minetest_client_commands[0x20] = { "GETBLOCK", 2 }
+minetest_client_obsolete[0x20] = true
+
+-- TOSERVER_ADDNODE (obsolete)
+
+minetest_client_commands[0x21] = { "ADDNODE", 2 }
+minetest_client_obsolete[0x21] = true
+
+-- TOSERVER_REMOVENODE (obsolete)
+
+minetest_client_commands[0x22] = { "REMOVENODE", 2 }
+minetest_client_obsolete[0x22] = true
+
+-- TOSERVER_PLAYERPOS
+
+do
+	local f_x = ProtoField.int32("minetest.client.playerpos_x", "Position X", base.DEC)
+	local f_y = ProtoField.int32("minetest.client.playerpos_y", "Position Y", base.DEC)
+	local f_z = ProtoField.int32("minetest.client.playerpos_z", "Position Z", base.DEC)
+	local f_speed_x = ProtoField.int32("minetest.client.playerpos_speed_x", "Speed X", base.DEC)
+	local f_speed_y = ProtoField.int32("minetest.client.playerpos_speed_y", "Speed Y", base.DEC)
+	local f_speed_z = ProtoField.int32("minetest.client.playerpos_speed_z", "Speed Z", base.DEC)
+	local f_pitch = ProtoField.int32("minetest.client.playerpos_pitch", "Pitch", base.DEC)
+	local f_yaw = ProtoField.int32("minetest.client.playerpos_yaw", "Yaw", base.DEC)
+
+	minetest_client_commands[0x23] = {
+		"PLAYERPOS", 34,
+		{ f_x, f_y, f_z, f_speed_x, f_speed_y, f_speed_z, f_pitch, f_yaw },
+		function(buffer, pinfo, tree, t)
+			t:add(f_x, buffer(2,4))
+			t:add(f_y, buffer(6,4))
+			t:add(f_z, buffer(10,4))
+			t:add(f_speed_x, buffer(14,4))
+			t:add(f_speed_y, buffer(18,4))
+			t:add(f_speed_z, buffer(22,4))
+			t:add(f_pitch, buffer(26,4))
+			t:add(f_yaw, buffer(30,4))
+		end
+	}
+end
+
+-- TOSERVER_GOTBLOCKS
+
+do
+	local f_count = ProtoField.uint8("minetest.client.gotblocks_count", "Count", base.DEC)
+	local f_block = ProtoField.bytes("minetset.client.gotblocks_block", "Block", base.DEC)
+	local f_x = ProtoField.int16("minetest.client.gotblocks_x", "Block position X", base.DEC)
+	local f_y = ProtoField.int16("minetest.client.gotblocks_y", "Block position Y", base.DEC)
+	local f_z = ProtoField.int16("minetest.client.gotblocks_z", "Block position Z", base.DEC)
+
+	minetest_client_commands[0x24] = {
+		"GOTBLOCKS", 3,
+		{ f_count, f_block, f_x, f_y, f_z },
+		function(buffer, pinfo, tree, t)
+			t:add(f_count, buffer(2,1))
+			local count = buffer(2,1):uint()
+			if minetest_check_length(buffer, 3 + 6*count, t) then
+				pinfo.cols.info:append(" * " .. count)
+				local index
+				for index = 0, count - 1 do
+					local pos = 3 + 6*index
+					local t2 = t:add(f_block, buffer(pos, 6))
+					t2:set_text("Block, X: " .. buffer(pos, 2):int()
+						.. ", Y: " .. buffer(pos + 2, 2):int()
+						.. ", Z: " .. buffer(pos + 4, 2):int())
+					t2:add(f_x, buffer(pos, 2))
+					t2:add(f_y, buffer(pos + 2, 2))
+					t2:add(f_z, buffer(pos + 4, 2))
+				end
+			end
+		end
+	}
+end
+
+-- TOSERVER_DELETEDBLOCKS
+-- TODO: Test this
+
+do
+	local f_count = ProtoField.uint8("minetest.client.deletedblocks_count", "Count", base.DEC)
+	local f_block = ProtoField.bytes("minetset.client.deletedblocks_block", "Block", base.DEC)
+	local f_x = ProtoField.int16("minetest.client.deletedblocks_x", "Block position X", base.DEC)
+	local f_y = ProtoField.int16("minetest.client.deletedblocks_y", "Block position Y", base.DEC)
+	local f_z = ProtoField.int16("minetest.client.deletedblocks_z", "Block position Z", base.DEC)
+
+	minetest_client_commands[0x25] = {
+		"DELETEDBLOCKS", 3,
+		{ f_count, f_block, f_x, f_y, f_z },
+		function(buffer, pinfo, tree, t)
+			t:add(f_count, buffer(2,1))
+			local count = buffer(2,1):uint()
+			if minetest_check_length(buffer, 3 + 6*count, t) then
+				pinfo.cols.info:append(" * " .. count)
+				local index
+				for index = 0, count - 1 do
+					local pos = 3 + 6*index
+					local t2 = t:add(f_block, buffer(pos, 6))
+					t2:set_text("Block, X: " .. buffer(pos, 2):int()
+						.. ", Y: " .. buffer(pos + 2, 2):int()
+						.. ", Z: " .. buffer(pos + 4, 2):int())
+					t2:add(f_x, buffer(pos, 2))
+					t2:add(f_y, buffer(pos + 2, 2))
+					t2:add(f_z, buffer(pos + 4, 2))
+				end
+			end
+		end
+	}
+end
+
+-- TOSERVER_ADDNODE_FROM_INVENTORY (obsolete)
+
+minetest_client_commands[0x26] = { "ADDNODE_FROM_INVENTORY", 2 }
+minetest_client_obsolete[0x26] = true
+
+-- TOSERVER_CLICK_OBJECT
+-- TODO: Test this
+
+do
+	local vs_button = {
+		[0] = "left",
+		[1] = "right"
+	}
+
+	local f_button = ProtoField.uint8("minetest.client.click_object_button", "Button", base.DEC, vs_button)
+	local f_blockpos_x = ProtoField.int16("minetest.client.click_object_blockpos_x", "Block position X", base.DEC)
+	local f_blockpos_y = ProtoField.int16("minetest.client.click_object_blockpos_y", "Block position Y", base.DEC)
+	local f_blockpos_z = ProtoField.int16("minetest.client.click_object_blockpos_z", "Block position Z", base.DEC)
+	local f_id = ProtoField.int16("minetest.client.click_object_id", "ID", base.DEC)
+	local f_item = ProtoField.uint16("minetest.client.click_object_item", "Item", base.DEC)
+
+	minetest_client_commands[0x27] = {
+		"CLICK_OBJECT", 13,
+		{ f_button, f_blockpos_x, f_blockpos_y, f_blockpos_z, f_id, f_item },
+		function(buffer, pinfo, tree, t)
+			t:add(f_button, buffer(2,1))
+			t:add(f_blockpos_x, buffer(3,2))
+			t:add(f_blockpos_y, buffer(5,2))
+			t:add(f_blockpos_z, buffer(7,2))
+			t:add(f_id, buffer(9,2))
+			t:add(f_item, buffer(11,2))
+		end
+	}
+end
+
+-- TOSERVER_GROUND_ACTION
+
+do
+	local vs_action = {
+		[0] = "Start digging",
+		[1] = "Place block",
+		[2] = "Stop digging",
+		[3] = "Digging completed"
+	}
+
+	local f_action = ProtoField.uint8("minetest.client.ground_action", "Action", base.DEC, vs_action)
+	local f_nodepos_undersurface_x = ProtoField.int16(
+		"minetest.client.ground_action_nodepos_undersurface_x",
+		"Node position (under surface) X")
+	local f_nodepos_undersurface_y = ProtoField.int16(
+		"minetest.client.ground_action_nodepos_undersurface_y",
+		"Node position (under surface) Y")
+	local f_nodepos_undersurface_z = ProtoField.int16(
+		"minetest.client.ground_action_nodepos_undersurface_z",
+		"Node position (under surface) Z")
+	local f_nodepos_abovesurface_x = ProtoField.int16(
+		"minetest.client.ground_action_nodepos_abovesurface_x",
+		"Node position (above surface) X")
+	local f_nodepos_abovesurface_y = ProtoField.int16(
+		"minetest.client.ground_action_nodepos_abovesurface_y",
+		"Node position (above surface) Y")
+	local f_nodepos_abovesurface_z = ProtoField.int16(
+		"minetest.client.ground_action_nodepos_abovesurface_z",
+		"Node position (above surface) Z")
+	local f_item = ProtoField.uint16("minetest.client.ground_action_item", "Item")
+
+	minetest_client_commands[0x28] = {
+		"GROUND_ACTION", 17,
+		{ f_action,
+		  f_nodepos_undersurface_x,
+		  f_nodepos_undersurface_y,
+		  f_nodepos_undersurface_z,
+		  f_nodepos_abovesurface_x,
+		  f_nodepos_abovesurface_y,
+		  f_nodepos_abovesurface_z,
+		  f_item },
+		function(buffer, pinfo, tree, t)
+			t:add(f_action, buffer(2,1))
+			t:add(f_nodepos_undersurface_x, buffer(3,2))
+			t:add(f_nodepos_undersurface_y, buffer(5,2))
+			t:add(f_nodepos_undersurface_z, buffer(7,2))
+			t:add(f_nodepos_abovesurface_x, buffer(9,2))
+			t:add(f_nodepos_abovesurface_y, buffer(11,2))
+			t:add(f_nodepos_abovesurface_z, buffer(13,2))
+			t:add(f_item, buffer(15,2))
+		end
+	}
+end
+
+-- TOSERVER_RELEASE (obsolete)
+
+minetest_client_commands[0x29] = { "RELEASE", 2 }
+minetest_client_obsolete[0x29] = true
+
+-- TOSERVER_SIGNTEXT (old signs)
+-- TODO: Test this or mark obsolete
+
+do
+	local f_blockpos_x = ProtoField.int16("minetest.client.signtext_blockpos_x", "Block position X", base.DEC)
+	local f_blockpos_y = ProtoField.int16("minetest.client.signtext_blockpos_y", "Block position Y", base.DEC)
+	local f_blockpos_z = ProtoField.int16("minetest.client.signtext_blockpos_z", "Block position Z", base.DEC)
+	local f_id = ProtoField.int16("minetest.client.signtext_id", "ID", base.DEC)
+	local f_textlen = ProtoField.uint16("minetest.client.signtext_textlen", "Text length", base.DEC)
+	local f_text = ProtoField.string("minetest.client.signtext_text", "Text")
+
+	minetest_client_commands[0x30] = {
+		"SIGNTEXT", 12,
+		{ f_blockpos_x, f_blockpos_y, f_blockpos_z, f_id, f_textlen, f_text },
+		function(buffer, pinfo, tree, t)
+			t:add(f_blockpos_x, buffer(2,2))
+			t:add(f_blockpos_y, buffer(4,2))
+			t:add(f_blockpos_z, buffer(6,2))
+			t:add(f_id, buffer(8,2))
+			t:add(f_textlen, buffer(10,2))
+			local textlen = buffer(10,2):uint()
+			if minetest_check_length(buffer, 12 + textlen, t) then
+				t:add(f_text, buffer, buffer(12,textlen))
+			end
+		end
+	}
+end
+
+-- TOSERVER_INVENTORY_ACTION
+
+do
+	local f_action = ProtoField.string("minetest.client.inventory_action", "Action")
+
+	minetest_client_commands[0x31] = {
+		"INVENTORY_ACTION", 2,
+		{ f_action },
+		function(buffer, pinfo, tree, t)
+			t:add(f_action, buffer(2, buffer:len() - 2))
+		end
+	}
+end
+
+-- TOSERVER_CHAT_MESSAGE
+
+do
+	local f_length = ProtoField.uint16("minetest.client.chat_message_length", "Length", base.DEC)
+	local f_message = ProtoField.string("minetest.client.chat_message", "Message")
+
+	minetest_client_commands[0x32] = {
+		"CHAT_MESSAGE", 4,
+		{ f_length, f_message },
+		function(buffer, pinfo, tree, t)
+			t:add(f_length, buffer(2,2))
+			local textlen = buffer(2,2):uint()
+			if minetest_check_length(buffer, 4 + textlen*2, t) then
+				t:add(f_message, minetest_convert_utf16(buffer(4, textlen*2), "Converted chat message"))
+			end
+		end
+	}
+end
+
+-- TOSERVER_SIGNNODETEXT
+
+do
+	local f_pos_x = ProtoField.int16("minetest.client.signnodetext_pos_x", "Block position X", base.DEC)
+	local f_pos_y = ProtoField.int16("minetest.client.signnodetext_pos_y", "Block position Y", base.DEC)
+	local f_pos_z = ProtoField.int16("minetest.client.signnodetext_pos_z", "Block position Z", base.DEC)
+	local f_textlen = ProtoField.uint16("minetest.client.signnodetext_textlen", "Text length", base.DEC)
+	local f_text = ProtoField.string("minetest.client.signnodetext_text", "Text")
+
+	minetest_client_commands[0x33] = {
+		"SIGNNODETEXT", 10,
+		{ f_pos_x, f_pos_y, f_pos_z, f_textlen, f_text },
+		function(buffer, pinfo, tree, t)
+			t:add(f_pos_x, buffer(2,2))
+			t:add(f_pos_y, buffer(4,2))
+			t:add(f_pos_z, buffer(6,2))
+			t:add(f_textlen, buffer(8,2))
+			local textlen = buffer(8,2):uint()
+			if minetest_check_length(buffer, 10 + textlen, t) then
+				t:add(f_text, buffer(10, textlen))
+			end
+		end
+	}
+end
+
+-- TOSERVER_CLICK_ACTIVEOBJECT
+
+do
+	local vs_button = {
+		[0] = "left",
+		[1] = "right"
+	}
+
+	local f_button = ProtoField.uint8("minetest.client.click_activeobject_button", "Button", base.DEC, vs_button)
+	local f_id = ProtoField.uint16("minetest.client.click_activeobject_id", "ID", base.DEC)
+	local f_item = ProtoField.uint16("minetest.client.click_activeobject_item", "Item", base.DEC)
+
+	minetest_client_commands[0x34] = {
+		"CLICK_ACTIVEOBJECT", 7,
+		{ f_button, f_id, f_item },
+		function(buffer, pinfo, tree, t)
+			t:add(f_button, buffer(2,1))
+			t:add(f_id, buffer(3,2))
+			t:add(f_item, buffer(5,2))
+		end
+	}
+end
+
+-- TOSERVER_DAMAGE
+
+do
+	local f_amount = ProtoField.uint8("minetest.client.damage_amount", "Amount", base.DEC)
+
+	minetest_client_commands[0x35] = {
+		"DAMAGE", 3,
+		{ f_amount },
+		function(buffer, pinfo, tree, t)
+			t:add(f_amount, buffer(2,1))
+		end
+	}
+end
+
+-- TOSERVER_PASSWORD
+
+do
+	local f_old_password = ProtoField.string("minetest.client.password_old", "Old password")
+	local f_new_password = ProtoField.string("minetest.client.password_new", "New password")
+
+	minetest_client_commands[0x36] = {
+		"PASSWORD", 58,
+		{ f_old_password, f_new_password },
+		function(buffer, pinfo, tree, t)
+			t:add(f_old_password, buffer(2,28))
+			t:add(f_new_password, buffer(30,28))
+		end
+	}
+end
+
+-- TOSERVER_PLAYERITEM
+
+do
+	local f_item = ProtoField.uint16("minetest.client.playeritem_item", "Wielded item")
+
+	minetest_client_commands[0x37] = {
+		"PLAYERITEM", 4,
+		{ f_item },
+		function(buffer, pinfo, tree, t)
+			t:add(f_item, buffer(2,2))
+		end
+	}
+end
+
+
+
+
+--------------------------------------------
+-- Part 2                                 --
+-- Server command dissectors (TOCLIENT_*) --
+--------------------------------------------
+
+minetest_server_commands = {}
+minetest_server_obsolete = {}
+
+-- TOCLIENT_INIT
+
+do
+	local f_version = ProtoField.uint8("minetest.server.init_version", "Deployed version", base.DEC)
+	local f_pos_x = ProtoField.int16("minetest.server.init_pos_x", "Position X", base.DEC)
+	local f_pos_y = ProtoField.int16("minetest.server.init_pos_y", "Position Y", base.DEC)
+	local f_pos_z = ProtoField.int16("minetest.server.init_pos_x", "Position Z", base.DEC)
+	local f_map_seed = ProtoField.uint64("minetest.server.init_map_seed", "Map seed", base.DEC)
+
+	minetest_server_commands[0x10] = {
+		"INIT", 17,
+		{ f_version, f_pos_x, f_pos_y, f_pos_z, f_map_seed },
+		function(buffer, pinfo, tree, t)
+			t:add(f_version, buffer(2,1))
+			t:add(f_pos_x, buffer(3,2))
+			t:add(f_pos_y, buffer(5,2))
+			t:add(f_pos_z, buffer(7,2))
+			t:add(f_map_seed, buffer(9,8))
+		end
+	}
+end
+
+-- TOCLIENT_BLOCKDATA
+
+do
+	local f_x = ProtoField.int16("minetest.server.blockdata_x", "Block position X", base.DEC)
+	local f_y = ProtoField.int16("minetest.server.blockdata_y", "Block position Y", base.DEC)
+	local f_z = ProtoField.int16("minetest.server.blockdata_z", "Block position Z", base.DEC)
+	local f_data = ProtoField.bytes("minetest.server.blockdata_block", "Serialized MapBlock")
+
+	minetest_server_commands[0x20] = {
+		"BLOCKDATA", 8,
+		{ f_x, f_y, f_z, f_data },
+		function(buffer, pinfo, tree, t)
+			t:add(f_x, buffer(2,2))
+			t:add(f_y, buffer(4,2))
+			t:add(f_z, buffer(6,2))
+			t:add(f_data, buffer(8, buffer:len() - 8))
+		end
+	}
+end
+
+-- TOCLIENT_ADDNODE
+
+do
+	local f_x = ProtoField.int16("minetest.server.addnode_x", "Position X", base.DEC)
+	local f_y = ProtoField.int16("minetest.server.addnode_y", "Position Y", base.DEC)
+	local f_z = ProtoField.int16("minetest.server.addnode_z", "Position Z", base.DEC)
+	local f_data = ProtoField.bytes("minetest.server.addnode_node", "Serialized MapNode")
+
+	minetest_server_commands[0x21] = {
+		"ADDNODE", 8,
+		{ f_x, f_y, f_z, f_data },
+		function(buffer, pinfo, tree, t)
+			t:add(f_x, buffer(2,2))
+			t:add(f_y, buffer(4,2))
+			t:add(f_z, buffer(6,2))
+			t:add(f_data, buffer(8, buffer:len() - 8))
+		end
+	}
+end
+
+-- TOCLIENT_REMOVENODE
+
+do
+	local f_x = ProtoField.int16("minetest.server.removenode_x", "Position X", base.DEC)
+	local f_y = ProtoField.int16("minetest.server.removenode_y", "Position Y", base.DEC)
+	local f_z = ProtoField.int16("minetest.server.removenode_z", "Position Z", base.DEC)
+
+	minetest_server_commands[0x22] = {
+		"REMOVENODE", 8,
+		{ f_x, f_y, f_z },
+		function(buffer, pinfo, tree, t)
+			t:add(f_x, buffer(2,2))
+			t:add(f_y, buffer(4,2))
+			t:add(f_z, buffer(6,2))
+		end
+	}
+end
+
+-- TOCLIENT_PLAYERPOS (obsolete)
+
+minetest_server_commands[0x23] = { "PLAYERPOS", 2 }
+minetest_server_obsolete[0x23] = true
+
+-- TOCLIENT_PLAYERINFO
+
+do
+	local f_count = ProtoField.uint16("minetest.server.playerinfo_count", "Count", base.DEC)
+	local f_player = ProtoField.bytes("minetest.server.playerinfo_player", "Player", base.DEC)
+	local f_peer_id = ProtoField.uint16("minetest.server.playerinfo_peer_id", "Peer ID", base.DEC)
+	local f_name = ProtoField.string("minetest.server.playerinfo_name", "Name")
+
+	minetest_server_commands[0x24] = {
+		"PLAYERINFO", 2,
+		{ f_count, f_player, f_peer_id, f_name },
+		function(buffer, pinfo, tree, t)
+			local count = 0
+			local pos, index
+			for pos = 2, buffer:len() - 22, 22 do  -- does lua have integer division?
+				count = count + 1
+			end
+			t:add(f_count, count):set_generated()
+			t:set_len(2 + 22 * count)
+			pinfo.cols.info:append(" * " .. count)
+			for index = 0, count - 1 do
+				local pos = 2 + 22 * index
+				local t2 = t:add(f_player, buffer(pos, 22))
+				t2:set_text("Player, ID: " .. buffer(pos, 2):uint()
+					.. ", Name: " .. buffer(pos + 2, 20):string())
+				t2:add(f_peer_id, buffer(pos, 2))
+				t2:add(f_name, buffer(pos + 2, 20))
+			end
+		end
+	}
+end
+
+-- TOCLIENT_OPT_BLOCK_NOT_FOUND (obsolete)
+
+minetest_server_commands[0x25] = { "OPT_BLOCK_NOT_FOUND", 2 }
+minetest_server_obsolete[0x25] = true
+
+-- TOCLIENT_SECTORMETA (obsolete)
+
+minetest_server_commands[0x26] = { "SECTORMETA", 2 }
+minetest_server_obsolete[0x26] = true
+
+-- TOCLIENT_INVENTORY
+
+do
+	local f_inventory = ProtoField.string("minetest.server.inventory", "Inventory")
+
+	minetest_server_commands[0x27] = {
+		"INVENTORY", 2,
+		{ f_inventory },
+		function(buffer, pinfo, tree, t)
+			t:add(f_inventory, buffer(2, buffer:len() - 2))
+		end
+	}
+end
+
+-- TOCLIENT_OBJECTDATA
+
+do
+	local f_player_count = ProtoField.uint16("minetest.server.objectdata_player_count",
+		"Count of player positions", base.DEC)
+	local f_player = ProtoField.bytes("minetest.server.objectdata_player", "Player position")
+	local f_peer_id = ProtoField.uint16("minetest.server.objectdata_player_peer_id", "Peer ID")
+	local f_x = ProtoField.int32("minetest.server.objectdata_player_x", "Position X", base.DEC)
+	local f_y = ProtoField.int32("minetest.server.objectdata_player_y", "Position Y", base.DEC)
+	local f_z = ProtoField.int32("minetest.server.objectdata_player_z", "Position Z", base.DEC)
+	local f_speed_x = ProtoField.int32("minetest.server.objectdata_player_speed_x", "Speed X", base.DEC)
+	local f_speed_y = ProtoField.int32("minetest.server.objectdata_player_speed_y", "Speed Y", base.DEC)
+	local f_speed_z = ProtoField.int32("minetest.server.objectdata_player_speed_z", "Speed Z", base.DEC)
+	local f_pitch = ProtoField.int32("minetest.server.objectdata_player_pitch", "Pitch", base.DEC)
+	local f_yaw = ProtoField.int32("minetest.server.objectdata_player_yaw", "Yaw", base.DEC)
+	local f_block_count = ProtoField.uint16("minetest.server.objectdata_block_count",
+		"Count of blocks", base.DEC)
+
+	minetest_server_commands[0x28] = {
+		"OBJECTDATA", 6,
+		{ f_player_count, f_player, f_peer_id, f_x, f_y, f_z,
+		  f_speed_x, f_speed_y, f_speed_z,f_pitch, f_yaw,
+		  f_block_count },
+		function(buffer, pinfo, tree, t)
+			local t2, index, pos
+
+			local player_count_pos = 2
+			local player_count = buffer(player_count_pos, 2):uint()
+			t:add(f_player_count, buffer(player_count_pos, 2))
+
+			local block_count_pos = player_count_pos + 2 + 34 * player_count
+			if not minetest_check_length(buffer, block_count_pos + 2, t) then
+				return
+			end
+
+			for index = 0, player_count - 1 do
+				pos = player_count_pos + 2 + 34 * index
+				t2 = t:add(f_player, buffer(pos, 34))
+				t2:set_text("Player position, ID: " .. buffer(pos, 2):uint())
+				t2:add(f_peer_id, buffer(pos, 2))
+				t2:add(f_x, buffer(pos + 2, 4))
+				t2:add(f_y, buffer(pos + 6, 4))
+				t2:add(f_z, buffer(pos + 10, 4))
+				t2:add(f_speed_x, buffer(pos + 14, 4))
+				t2:add(f_speed_y, buffer(pos + 18, 4))
+				t2:add(f_speed_z, buffer(pos + 22, 4))
+				t2:add(f_pitch, buffer(pos + 26, 4))
+				t2:add(f_yaw, buffer(pos + 30, 4))
+			end
+
+			local block_count = buffer(block_count_pos, 2):uint()
+			t:add(f_block_count, buffer(block_count_pos, 2))
+
+			-- TODO: dissect blocks.
+			-- NOTE: block_count > 0 is obsolete. (?)
+
+			pinfo.cols.info:append(" * " .. (player_count + block_count))
+		end
+	}
+end
+
+-- TOCLIENT_TIME_OF_DAY
+
+do
+	local f_time = ProtoField.uint16("minetest.server.time_of_day", "Time", base.DEC)
+
+	minetest_server_commands[0x29] = {
+		"TIME_OF_DAY", 4,
+		{ f_time },
+		function(buffer, pinfo, tree, t)
+			t:add(f_time, buffer(2,2))
+		end
+	}
+end
+
+-- TOCLIENT_CHAT_MESSAGE
+
+do
+	local f_length = ProtoField.uint16("minetest.server.chat_message_length", "Length", base.DEC)
+	local f_message = ProtoField.string("minetest.server.chat_message", "Message")
+
+	minetest_server_commands[0x30] = {
+		"CHAT_MESSAGE", 4,
+		{ f_length, f_message },
+		function(buffer, pinfo, tree, t)
+			t:add(f_length, buffer(2,2))
+			local textlen = buffer(2,2):uint()
+			if minetest_check_length(buffer, 4 + textlen*2, t) then
+				t:add(f_message, minetest_convert_utf16(buffer(4, textlen*2), "Converted chat message"))
+			end
+		end
+	}
+end
+
+-- TOCLIENT_ACTIVE_OBJECT_REMOVE_ADD
+
+do
+	local f_removed_count = ProtoField.uint16(
+		"minetest.server.active_object_remove_add_removed_count",
+		"Count of removed objects", base.DEC)
+	local f_removed = ProtoField.bytes(
+		"minetest.server.active_object_remove_add_removed",
+		"Removed object")
+	local f_removed_id = ProtoField.uint16(
+		"minetest.server.active_object_remove_add_removed_id",
+		"ID", base.DEC)
+
+	local f_added_count = ProtoField.uint16(
+		"minetest.server.active_object_remove_add_added_count",
+		"Count of added objects", base.DEC)
+	local f_added = ProtoField.bytes(
+		"minetest.server.active_object_remove_add_added",
+		"Added object")
+	local f_added_id = ProtoField.uint16(
+		"minetest.server.active_object_remove_add_added_id",
+		"ID", base.DEC)
+	local f_added_type = ProtoField.uint8(
+		"minetest.server.active_object_remove_add_added_type",
+		"Type", base.DEC)
+	local f_added_init_length = ProtoField.uint32(
+		"minetest.server.active_object_remove_add_added_init_length",
+		"Initialization data length", base.DEC)
+	local f_added_init_data = ProtoField.bytes(
+		"minetest.server.active_object_remove_add_added_init_data",
+		"Initialization data")
+
+	minetest_server_commands[0x31] = {
+		"ACTIVE_OBJECT_REMOVE_ADD", 6,
+		{ f_removed_count, f_removed, f_removed_id,
+		  f_added_count, f_added, f_added_id,
+		  f_added_type, f_added_init_length, f_added_init_data },
+		function(buffer, pinfo, tree, t)
+			local t2, index, pos
+
+			local removed_count_pos = 2
+			local removed_count = buffer(removed_count_pos, 2):uint()
+			t:add(f_removed_count, buffer(removed_count_pos, 2))
+
+			local added_count_pos = removed_count_pos + 2 + 2 * removed_count
+			if not minetest_check_length(buffer, added_count_pos + 2, t) then
+				return
+			end
+
+			-- Loop through removed active objects
+			for index = 0, removed_count - 1 do
+				pos = removed_count_pos + 2 + 2 * index
+				t2 = t:add(f_removed, buffer(pos, 2))
+				t2:set_text("Removed object, ID = " ..  buffer(pos, 2):uint())
+				t2:add(f_removed_id, buffer(pos, 2))
+			end
+
+			local added_count = buffer(added_count_pos, 2):uint()
+			t:add(f_added_count, buffer(added_count_pos, 2))
+
+			-- Loop through added active objects
+			pos = added_count_pos + 2
+			for index = 0, added_count - 1 do
+				if not minetest_check_length(buffer, pos + 7, t) then
+					return
+				end
+
+				local init_length = buffer(pos + 3, 4):uint()
+				if not minetest_check_length(buffer, pos + 7 + init_length, t) then
+					return
+				end
+
+				t2 = t:add(f_added, buffer(pos, 7 + init_length))
+				t2:set_text("Added object, ID = " .. buffer(pos, 2):uint())
+				t2:add(f_added_id, buffer(pos, 2))
+				t2:add(f_added_type, buffer(pos + 2, 1))
+				t2:add(f_added_init_length, buffer(pos + 3, 4))
+				t2:add(f_added_init_data, buffer(pos + 7, init_length))
+
+				pos = pos + 7 + init_length
+			end
+
+			pinfo.cols.info:append(" * " .. (removed_count + added_count))
+		end
+	}
+end
+
+-- TOCLIENT_ACTIVE_OBJECT_MESSAGES
+
+do
+	local f_object_count = ProtoField.uint16(
+		"minetest.server.active_object_messages_object_count",
+		"Count of objects", base.DEC)
+	local f_object = ProtoField.bytes(
+		"minetest.server.active_object_messages_object",
+		"Object")
+	local f_object_id = ProtoField.uint16(
+		"minetest.server.active_object_messages_id",
+		"ID", base.DEC)
+	local f_message_length = ProtoField.uint16(
+		"minetest.server.active_object_messages_message_length",
+		"Message length", base.DEC)
+	local f_message = ProtoField.bytes(
+		"minetest.server.active_object_messages_message",
+		"Message")
+
+	minetest_server_commands[0x32] = {
+		"ACTIVE_OBJECT_MESSAGES", 2,
+		{ f_object_count, f_object, f_object_id, f_message_length, f_message },
+		function(buffer, pinfo, tree, t)
+			local t2, count, pos, message_length
+
+			count = 0
+			pos = 2
+			while pos < buffer:len() do
+				if not minetest_check_length(buffer, pos + 4, t) then
+					return
+				end
+				message_length = buffer(pos + 2, 2):uint()
+				if not minetest_check_length(buffer, pos + 4 + message_length, t) then
+					return
+				end
+				count = count + 1
+				pos = pos + 4 + message_length
+			end
+
+			pinfo.cols.info:append(" * " .. count)
+			t:add(f_object_count, count):set_generated()
+
+			pos = 2
+			while pos < buffer:len() do
+				message_length = buffer(pos + 2, 2):uint()
+
+				t2 = t:add(f_object, buffer(pos, 4 + message_length))
+				t2:set_text("Object, ID = " ..  buffer(pos, 2):uint())
+				t2:add(f_object_id, buffer(pos, 2))
+				t2:add(f_message_length, buffer(pos + 2, 2))
+				t2:add(f_message, buffer(pos + 4, message_length))
+
+				pos = pos + 4 + message_length
+			end
+		end
+	}
+end
+
+-- TOCLIENT_HP
+
+do
+	local f_hp = ProtoField.uint8("minetest.server.hp", "Hitpoints", base.DEC)
+
+	minetest_server_commands[0x33] = {
+		"HP", 3,
+		{ f_hp },
+		function(buffer, pinfo, tree, t)
+			t:add(f_hp, buffer(2,1))
+		end
+	}
+end
+
+-- TOCLIENT_MOVE_PLAYER
+
+do
+	local f_x = ProtoField.int32("minetest.server.move_player_x", "Position X", base.DEC)
+	local f_y = ProtoField.int32("minetest.server.move_player_y", "Position Y", base.DEC)
+	local f_z = ProtoField.int32("minetest.server.move_player_z", "Position Z", base.DEC)
+	local f_pitch = ProtoField.int32("minetest.server.move_player_pitch", "Pitch", base.DEC)
+	local f_yaw = ProtoField.int32("minetest.server.move_player_yaw", "Yaw", base.DEC)
+	local f_garbage = ProtoField.bytes("minetest.server.move_player_garbage", "Garbage")
+
+	minetest_server_commands[0x34] = {
+		"MOVE_PLAYER", 18,  -- actually 22, but see below
+		{ f_x, f_y, f_z, f_pitch, f_yaw, f_garbage },
+		function(buffer, pinfo, tree, t)
+			t:add(f_x, buffer(2, 4))
+			t:add(f_y, buffer(6, 4))
+			t:add(f_z, buffer(10, 4))
+
+			-- Compatibility note:
+			-- Up to 2011-08-23, there was a bug in Minetest that
+			-- caused the server to serialize the pitch and yaw
+			-- with 2 bytes each instead of 4, creating a
+			-- malformed message.
+			if buffer:len() >= 22 then
+				t:add(f_pitch, buffer(14, 4))
+				t:add(f_yaw, buffer(18, 4))
+			else
+				t:add(f_garbage, buffer(14, 4))
+				t:add_expert_info(PI_MALFORMED, PI_WARN, "Malformed pitch and yaw, possibly caused by a serialization bug in Minetest")
+			end
+		end
+	}
+end
+
+-- TOCLIENT_ACCESS_DENIED
+
+do
+	local f_reason_length = ProtoField.uint16("minetest.server.access_denied_reason_length", "Reason length", base.DEC)
+	local f_reason = ProtoField.string("minetest.server.access_denied_reason", "Reason")
+
+	minetest_server_commands[0x35] = {
+		"ACCESS_DENIED", 4,
+		{ f_reason_length, f_reason },
+		function(buffer, pinfo, tree, t)
+			t:add(f_reason_length, buffer(2,2))
+			local reason_length = buffer(2,2):uint()
+			if minetest_check_length(buffer, 4 + reason_length * 2, t) then
+				t:add(f_reason, minetest_convert_utf16(buffer(4, reason_length * 2), "Converted reason message"))
+			end
+		end
+	}
+end
+
+-- TOCLIENT_PLAYERITEM
+
+do
+	local f_count = ProtoField.uint16(
+		"minetest.server.playeritem_count",
+		"Count of players", base.DEC)
+	local f_player = ProtoField.bytes(
+		"minetest.server.playeritem_player",
+		"Player")
+	local f_peer_id = ProtoField.uint16(
+		"minetest.server.playeritem_peer_id",
+		"Peer ID", base.DEC)
+	local f_item_length = ProtoField.uint16(
+		"minetest.server.playeritem_item_length",
+		"Item information length", base.DEC)
+	local f_item = ProtoField.string(
+		"minetest.server.playeritem_item",
+		"Item information")
+
+	minetest_server_commands[0x36] = {
+		"PLAYERITEM", 4,
+		{ f_count, f_player, f_peer_id, f_item_length, f_item },
+		function(buffer, pinfo, tree, t)
+			local count, index, pos, item_length
+
+			count = buffer(2,2):uint()
+			pinfo.cols.info:append(" * " .. count)
+			t:add(f_count, buffer(2,2))
+
+			pos = 4
+			for index = 0, count - 1 do
+				if not minetest_check_length(buffer, pos + 4, t) then
+					return
+				end
+				item_length = buffer(pos + 2, 2):uint()
+				if not minetest_check_length(buffer, pos + 4 + item_length, t) then
+					return
+				end
+
+				local t2 = t:add(f_player, buffer(pos, 4 + item_length))
+				t2:set_text("Player, ID: " .. buffer(pos, 2):uint())
+				t2:add(f_peer_id, buffer(pos, 2))
+				t2:add(f_item_length, buffer(pos + 2, 2))
+				t2:add(f_item, buffer(pos + 4, item_length))
+
+				pos = pos + 4 + item_length
+			end
+		end
+	}
+end
+
+
+
+
+------------------------------------
+-- Part 3                         --
+-- Wrapper protocol subdissectors --
+------------------------------------
+
+-- minetest.control dissector
+
+do
+	local p_control = Proto("minetest.control", "Minetest Control")
+
+	local vs_control_type = {
+		[0] = "Ack",
+		[1] = "Set Peer ID",
+		[2] = "Ping",
+		[3] = "Disco"
+	}
+
+	local f_control_type = ProtoField.uint8("minetest.control.type", "Control Type", base.DEC, vs_control_type)
+	local f_control_ack = ProtoField.uint16("minetest.control.ack", "ACK sequence number", base.DEC)
+	local f_control_peerid = ProtoField.uint8("minetest.control.peerid", "New peer ID", base.DEC)
+	p_control.fields = { f_control_type, f_control_ack, f_control_peerid }
+
+	local data_dissector = Dissector.get("data")
+
+	function p_control.dissector(buffer, pinfo, tree)
+		local t = tree:add(p_control, buffer(0,1))
+		t:add(f_control_type, buffer(0,1))
+
+		pinfo.cols.info = "Control message"
+
+		local pos = 1
+		if buffer(0,1):uint() == 0 then
+			pos = 3
+			t:set_len(3)
+			t:add(f_control_ack, buffer(1,2))
+			pinfo.cols.info = "Ack " .. buffer(1,2):uint()
+		elseif buffer(0,1):uint() == 1 then
+			pos = 3
+			t:set_len(3)
+			t:add(f_control_peerid, buffer(1,2))
+			pinfo.cols.info = "Set peer ID " .. buffer(1,2):uint()
+		elseif buffer(0,1):uint() == 2 then
+			pinfo.cols.info = "Ping"
+		elseif buffer(0,1):uint() == 3 then
+			pinfo.cols.info = "Disco"
+		end
+
+		data_dissector:call(buffer(pos):tvb(), pinfo, tree)
+	end
+end
+
+-- minetest.client dissector
+-- minetest.server dissector
+
+-- Defines the minetest.client or minetest.server Proto. These two protocols
+-- are created by the same function because they are so similar.
+-- Parameter: proto: the Proto object
+-- Parameter: this_peer: "Client" or "Server"
+-- Parameter: other_peer: "Server" or "Client"
+-- Parameter: commands: table of command information, built above
+-- Parameter: obsolete: table of obsolete commands, built above
+function minetest_define_client_or_server_proto(is_client)
+	-- Differences between minetest.client and minetest.server
+	local proto_name, this_peer, other_peer, empty_message_info
+	local commands, obsolete
+	if is_client then
+		proto_name = "minetest.client"
+		this_peer = "Client"
+		other_peer = "Server"
+		empty_message_info = "Empty message / Connect"
+		commands = minetest_client_commands  -- defined in Part 1
+		obsolete = minetest_client_obsolete  -- defined in Part 1
+	else
+		proto_name = "minetest.server"
+		this_peer = "Server"
+		other_peer = "Client"
+		empty_message_info = "Empty message"
+		commands = minetest_server_commands  -- defined in Part 2
+		obsolete = minetest_server_obsolete  -- defined in Part 2
+	end
+
+	-- Create the protocol object.
+	local proto = Proto(proto_name, "Minetest " .. this_peer .. " to " .. other_peer)
+
+	-- Create a table vs_command that maps command codes to command names.
+	local vs_command = {}
+	local code, command_info
+	for code, command_info in pairs(commands) do
+		local command_name = command_info[1]
+		vs_command[code] = "TO" .. other_peer:upper() .. "_" .. command_name
+	end
+
+	-- Field definitions
+	local f_command = ProtoField.uint16(proto_name .. ".command", "Command", base.HEX, vs_command)
+	local f_empty = ProtoField.bool(proto_name .. ".empty", "Is empty", BASE_NONE)
+	proto.fields = { f_command, f_empty }
+
+	-- Add command-specific fields to the protocol
+	for code, command_info in pairs(commands) do
+		local command_fields = command_info[3]
+		if command_fields ~= nil then
+			local index, field
+			for index, field in ipairs(command_fields) do
+				table.insert(proto.fields, field)
+			end
+		end
+	end
+
+	-- minetest.client or minetest.server dissector function
+	function proto.dissector(buffer, pinfo, tree)
+		local t = tree:add(proto, buffer)
+
+		pinfo.cols.info = this_peer
+
+		if buffer:len() == 0 then
+			-- Empty message.
+			t:add(f_empty, 1):set_generated()
+			pinfo.cols.info:append(": " .. empty_message_info)
+
+		elseif minetest_check_length(buffer, 2, t) then
+			-- Get the command code.
+			t:add(f_command, buffer(0,2))
+			local code = buffer(0,2):uint()
+			local command_info = commands[code]
+			if command_info == nil then
+				-- Error: Unknown command.
+				pinfo.cols.info:append(": Unknown command")
+				t:add_expert_info(PI_UNDECODED, PI_WARN, "Unknown " .. this_peer .. " to " .. other_peer .. " command")
+			else
+				-- Process a known command
+				local command_name = command_info[1]
+				local command_min_length = command_info[2]
+				local command_fields = command_info[3]
+				local command_dissector = command_info[4]
+				if minetest_check_length(buffer, command_min_length, t) then
+					pinfo.cols.info:append(": " .. command_name)
+					if command_dissector ~= nil then
+						command_dissector(buffer, pinfo, tree, t)
+					end
+				end
+				if obsolete[code] then
+					t:add_expert_info(PI_REQUEST_CODE, PI_WARN, "Obsolete command.")
+				end
+			end
+		end
+	end
+end
+
+minetest_define_client_or_server_proto(true)  -- minetest.client
+minetest_define_client_or_server_proto(false) -- minetest.server
+
+-- minetest.split dissector
+
+do
+	local p_split = Proto("minetest.split", "Minetest Split Message")
+
+	local f_split_seq = ProtoField.uint16("minetest.split.seq", "Sequence number", base.DEC)
+	local f_split_chunkcount = ProtoField.uint16("minetest.split.chunkcount", "Chunk count", base.DEC)
+	local f_split_chunknum = ProtoField.uint16("minetest.split.chunknum", "Chunk number", base.DEC)
+	local f_split_data = ProtoField.bytes("minetest.split.data", "Split message data")
+	p_split.fields = { f_split_seq, f_split_chunkcount, f_split_chunknum, f_split_data }
+
+	function p_split.dissector(buffer, pinfo, tree)
+		local t = tree:add(p_split, buffer(0,6))
+		t:add(f_split_seq, buffer(0,2))
+		t:add(f_split_chunkcount, buffer(2,2))
+		t:add(f_split_chunknum, buffer(4,2))
+		t:add(f_split_data, buffer(6))
+		pinfo.cols.info:append(" " .. buffer(0,2):uint() .. " chunk " .. buffer(4,2):uint() .. "/" .. buffer(2,2):uint())
+	end
+end
+
+
+
+
+-------------------------------------
+-- Part 4                          --
+-- Wrapper protocol main dissector --
+-------------------------------------
+
+-- minetest dissector
+
+do
+	local p_minetest = Proto("minetest", "Minetest")
+
+	local minetest_id = 0x4f457403
+	local vs_id = {
+		[minetest_id] = "Valid"
+	}
+
+	local vs_peer = {
+		[0] = "Inexistent",
+		[1] = "Server"
+	}
+
+	local vs_type = {
+		[0] = "Control",
+		[1] = "Original",
+		[2] = "Split",
+		[3] = "Reliable"
+	}
+
+	local f_id = ProtoField.uint32("minetest.id", "ID", base.HEX, vs_id)
+	local f_peer = ProtoField.uint16("minetest.peer", "Peer", base.DEC, vs_peer)
+	local f_channel = ProtoField.uint8("minetest.channel", "Channel", base.DEC)
+	local f_type = ProtoField.uint8("minetest.type", "Type", base.DEC, vs_type)
+	local f_seq = ProtoField.uint16("minetest.seq", "Sequence number", base.DEC)
+	local f_subtype = ProtoField.uint8("minetest.subtype", "Subtype", base.DEC, vs_type)
+
+	p_minetest.fields = { f_id, f_peer, f_channel, f_type, f_seq, f_subtype }
+
+	local data_dissector = Dissector.get("data")
+	local control_dissector = Dissector.get("minetest.control")
+	local client_dissector = Dissector.get("minetest.client")
+	local server_dissector = Dissector.get("minetest.server")
+	local split_dissector = Dissector.get("minetest.split")
+
+	function p_minetest.dissector(buffer, pinfo, tree)
+
+		-- Add Minetest tree item and verify the ID
+		local t = tree:add(p_minetest, buffer(0,8))
+		t:add(f_id, buffer(0,4))
+		if buffer(0,4):uint() ~= minetest_id then
+			t:add_expert_info(PI_UNDECODED, PI_WARN, "Invalid ID, this is not a Minetest packet")
+			return
+		end
+
+		-- ID is valid, so replace packet's shown protocol
+		pinfo.cols.protocol = "Minetest"
+		pinfo.cols.info = "Minetest"
+
+		-- Set the other header fields
+		t:add(f_peer, buffer(4,2))
+		t:add(f_channel, buffer(6,1))
+		t:add(f_type, buffer(7,1))
+		t:set_text("Minetest, Peer: " .. buffer(4,2):uint() .. ", Channel: " .. buffer(6,1):uint())
+
+		local reliability_info
+		if buffer(7,1):uint() == 3 then
+			-- Reliable message
+			reliability_info = "Seq=" .. buffer(8,2):uint()
+			t:set_len(11)
+			t:add(f_seq, buffer(8,2))
+			t:add(f_subtype, buffer(10,1))
+			pos = 10
+		else
+			-- Unreliable message
+			reliability_info = "Unrel"
+			pos = 7
+		end
+
+		if buffer(pos,1):uint() == 0 then
+			-- Control message, possibly reliable
+			control_dissector:call(buffer(pos+1):tvb(), pinfo, tree)
+		elseif buffer(pos,1):uint() == 1 then
+			-- Original message, possibly reliable
+			if buffer(4,2):uint() == 1 then
+				server_dissector:call(buffer(pos+1):tvb(), pinfo, tree)
+			else
+				client_dissector:call(buffer(pos+1):tvb(), pinfo, tree)
+			end
+		elseif buffer(pos,1):uint() == 2 then
+			-- Split message, possibly reliable
+			if buffer(4,2):uint() == 1 then
+				pinfo.cols.info = "Server: Split message"
+			else
+				pinfo.cols.info = "Client: Split message"
+			end
+			split_dissector:call(buffer(pos+1):tvb(), pinfo, tree)
+		elseif buffer(pos,1):uint() == 3 then
+			-- Doubly reliable message??
+			t:add_expert_info(PI_MALFORMED, PI_ERROR, "Reliable message wrapped in reliable message")
+		else
+			data_dissector:call(buffer(pos+1):tvb(), pinfo, tree)
+		end
+
+		pinfo.cols.info:append(" (" .. reliability_info .. ")")
+
+	end
+
+	-- FIXME Is there a way to let the dissector table check if the first payload bytes are 0x4f457403?
+	DissectorTable.get("udp.port"):add(30000, p_minetest)
+	DissectorTable.get("udp.port"):add(30001, p_minetest)
+end
+
+
+
+
+-----------------------
+-- Part 5            --
+-- Utility functions --
+-----------------------
+
+-- Checks if a (sub-)Tvb is long enough to be further dissected.
+-- If it is long enough, sets the dissector tree item length to min_len
+-- and returns true. If it is not long enough, adds expert info to the
+-- dissector tree and returns false.
+-- Parameter: tvb: the Tvb
+-- Parameter: min_len: required minimum length
+-- Parameter: t: dissector tree item
+-- Returns: true if tvb:len() >= min_len, false otherwise
+function minetest_check_length(tvb, min_len, t)
+	if tvb:len() >= min_len then
+		t:set_len(min_len)
+		return true
+
+	-- Tvb:reported_length_remaining() has been added in August 2011
+	-- and is not yet widely available, disable for the time being
+	-- TODO: uncomment at a later date
+	-- TODO: when uncommenting this, also re-check if other parts of
+	-- the dissector could benefit from reported_length_remaining
+	--elseif tvb:reported_length_remaining() >= min_len then
+	--	t:add_expert_info(PI_UNDECODED, PI_INFO, "Only part of this packet was captured, unable to decode.")
+	--	return false
+
+	else
+		t:add_expert_info(PI_MALFORMED, PI_ERROR, "Message is too short")
+		return false
+	end
+end
+
+-- Takes a Tvb or TvbRange (i.e. part of a packet) that
+-- contains a UTF-16 string and returns a TvbRange containing
+-- string converted to ASCII. Any characters outside the range
+-- 0x20 to 0x7e are replaced by a question mark.
+-- Parameter: tvb: Tvb or TvbRange that contains the UTF-16 data
+-- Parameter: name: will be the name of the newly created Tvb.
+-- Returns: New TvbRange containing the ASCII string.
+-- TODO: Handle surrogates (should only produce one question mark)
+-- TODO: Remove this when Wireshark supports UTF-16 strings natively.
+function minetest_convert_utf16(tvb, name)
+	local hex, pos, char
+	hex = ""
+	for pos = 0, tvb:len() - 2, 2 do
+		char = tvb(pos, 2):uint()
+		if (char >= 0x20) and (char <= 0x7e) then
+			hex = hex .. string.format(" %02x", char)
+		else
+			hex = hex .. " 3F"
+		end
+	end
+	return ByteArray.new(hex):tvb(name):range()
+end
+