small cleanup

1 files changed, 31 insertions, 30 deletions

diff --git a/wireshark/pictochat.lua b/wireshark/pictochat.lua
index b64832a..ff6c21f 100644
--- a/wireshark/pictochat.lua
+++ b/wireshark/pictochat.lua
@@ -18,15 +18,16 @@ local MSG_TYPE = {
 
 local MSG_TYPE_MAP = {
 	[MSG_TYPE.INIT] = "Init", -- sent once (init?)
-	[MSG_TYPE.MSG_START] = "Message start", -- sent before a message packet
-	[MSG_TYPE.MSG_END] = "Message end", -- sent after multi-frame message body packets
-	[MSG_TYPE.USER_JOIN] = "User join", -- these packets contain a username
-	[MSG_TYPE.STATUS] = "Status", -- constantly spammed (status?)
+	[MSG_TYPE.MSG_START] = "Message start", -- sent before message body and user join
+	[MSG_TYPE.MSG_END] = "Message end", -- (sometimes) sent after multi-frame message body packets
+	[MSG_TYPE.USER_JOIN] = "User join", -- contain nickname / message
+	[MSG_TYPE.STATUS] = "Status", -- constantly spammed, contains room users' addresses
 	[MSG_TYPE.MSG_BODY] = "Message body", -- contains tile data for drawing
 }
 
 p.fields.unknown = ProtoField.uint16("pictochat.unknown", "Unknown")
 
+p.fields.payload_len = ProtoField.uint16("pictochat.payload_len", "Payload length")
 local function dissect_payload(buffer, pinfo, tree)
 	tree:add_le(p.fields.payload_len, buffer(0x00, 2))
 	local payload_length = buffer(0x00, 2):le_uint()
@@ -45,7 +46,7 @@ dissect_msg_type[MSG_TYPE.MSG_START] = function (buffer, pinfo, tree)
 	payload:add_le(p.fields.msg_start_len, buffer(0x04, 2))
 	local start_len = buffer(0x04, 2):le_uint()
 
-	state.data_remaining = start_len
+	state.body_remaining = start_len
 	state.buf = ByteArray.new()
 	state.want_next = 0
 end
@@ -72,64 +73,60 @@ dissect_msg_type[MSG_TYPE.USER_JOIN] = function (buffer, pinfo, tree)
 	bday:add(p.fields.user_bday_day, buffer(0x5b, 1))
 end
 
-p.fields.payload_len = ProtoField.uint16("pictochat.payload_len", "Payload length")
-p.fields.data_len = ProtoField.uint8("pictochat.data_len", "Data length")
-p.fields.data_end = ProtoField.bool("pictochat.data_end", "Data end")
-p.fields.data_offset = ProtoField.uint16("pictochat.data_offset", "Data offset")
-p.fields.data_sequence = ProtoField.uint16("pictochat.data_sequence", "Data sequence")
-p.fields.data = ProtoField.bytes("pictochat.data", "Data")
-p.fields.sequence = ProtoField.uint16("pictochat.sequence", "Packet sequence")
+p.fields.body_len = ProtoField.uint8("pictochat.body.len", "Length")
+p.fields.body_end = ProtoField.bool("pictochat.body.end", "End")
+p.fields.body_offset = ProtoField.uint16("pictochat.body.offset", "Offset")
+p.fields.body_seq = ProtoField.uint16("pictochat.body.seq", "Sequence")
+p.fields.body = ProtoField.bytes("pictochat.body", "Data")
 dissect_msg_type[MSG_TYPE.MSG_BODY] = function (buffer, pinfo, tree)
 	local payload
 	buffer, payload = dissect_payload(buffer, pinfo, tree)
 
 	payload:add_le(p.fields.unknown, buffer(0x00, 2))
-	payload:add_le(p.fields.data_len, buffer(0x02, 1))
-	local data_length = buffer(0x02, 1):le_uint()
+	payload:add_le(p.fields.body_len, buffer(0x02, 1))
+	local body_len = buffer(0x02, 1):le_uint()
 
-	payload:add_le(p.fields.data_end, buffer(0x03, 1))
+	payload:add_le(p.fields.body_end, buffer(0x03, 1))
 	-- This appears to be some kind of offset for indicating where to store the
 	-- current frame's data in a larger buffer. Messages sent in multiple parts
 	-- increment this value by 160 for each new original (p.fields.original ==
 	-- True) message.
-	payload:add_le(p.fields.data_offset, buffer(0x04, 2))
-	local data_offset = buffer(0x04, 2):le_uint()
+	payload:add_le(p.fields.body_offset, buffer(0x04, 2))
+	local body_offset = buffer(0x04, 2):le_uint()
 	payload:add_le(p.fields.unknown, buffer(0x06, 2)) -- usually 0
 
 	buffer = buffer(0x08)
 	-- This appears to be the actual message data (the drawing) sent as an
 	-- array of 8x8 tiles.
-	payload:add(p.fields.data, buffer(0, data_length))
-	if state.want_next == data_offset then
-		state.want_next = data_offset + data_length
-		state.data_remaining = state.data_remaining - data_length
-		state.buf:append(buffer(0, data_length):bytes())
-		pinfo.cols.info = "Message body"
+	payload:add(p.fields.body, buffer(0, body_len))
+	if state.want_next == body_offset then
+		state.want_next = body_offset + body_len
+		state.body_remaining = state.body_remaining - body_len
+		state.buf:append(buffer(0, body_len:bytes()))
 		ByteArray.tvb(state.buf, "Complete message")
 	end
-	buffer = buffer(data_length)
+	buffer = buffer(body_len)
 
-	payload:add_le(p.fields.data_sequence, buffer(0x00, 2))
+	payload:add_le(p.fields.body_seq, buffer(0x00, 2))
 	payload:add_le(p.fields.unknown, buffer(0x02, 2)) -- copy
 end
 
 p.fields.status_addr = ProtoField.bytes("pictochat.status.addr", "Address", base.COLON)
+p.fields.status_seq = ProtoField.uint16("pictochat.status.seq", "Sequence")
 dissect_msg_type[MSG_TYPE.STATUS] = function (buffer, pinfo, tree)
 	local payload
 	buffer, payload = dissect_payload(buffer, pinfo, tree)
 
-	payload:add_le(p.fields.unknown, buffer(0x00, 2))
-	payload:add_le(p.fields.unknown, buffer(0x02, 2))
+	payload:add_le(p.fields.unknown, buffer(0x00, 4))
 
 	buffer = buffer(0x04)
 
 	for _ = 0, 15 do
-		-- payload:add(p.fields.status_addr, buffer(0, 6))
 		add_addr_le(payload, p.fields.status_addr, buffer(0, 6))
 		buffer = buffer(6)
 	end
 
-	payload:add_le(p.fields.unknown, buffer(0x00, 2))
+	payload:add_le(p.fields.status_seq, buffer(0x00, 2))
 	payload:add_le(p.fields.unknown, buffer(0x02, 2))
 end
 
@@ -139,6 +136,8 @@ p.fields.msg_type = ProtoField.uint8("pictochat.msg_type", "Message type", base.
 function p.dissector(buffer, pinfo, tree)
 	-- check magic
 	if buffer(0x00, 2):uint() ~= GAMEID.PICTOCHAT then return 0 end
+	-- check length (avoid errors)
+	if buffer:len() < 6 then return 0 end
 
 	local subtree = tree:add(p, buffer(), string.format("%s: %d bytes", p.description, buffer():len()))
 	local buffer_len = buffer():len()
@@ -156,7 +155,7 @@ function p.dissector(buffer, pinfo, tree)
 		pinfo.cols.info = msg_type_str
 	end
 
-	if msg_type == 0 then
+	if msg_type == MSG_TYPE.INIT then
 		-- no more content
 		return buffer_len
 	end
@@ -168,5 +167,7 @@ function p.dissector(buffer, pinfo, tree)
 	if subdissector ~= nil then
 		subdissector(buffer, pinfo, subtree)
 	end
+
+	return buffer_len
 end