Initial commit

1 files changed, 107 insertions, 0 deletions

diff --git a/util/snowcast-dissector/cs168_snowcast.lua b/util/snowcast-dissector/cs168_snowcast.lua
new file mode 100644
index 0000000..5389035
--- /dev/null
+++ b/util/snowcast-dissector/cs168_snowcast.lua
@@ -0,0 +1,107 @@
+-- CS168 Snowcast Protocol Dissector
+
+snowcast_protocol = Proto("CS168Snowcast", "CS168 Snowcast Protocol")
+
+message = ProtoField.uint8("cs168snowcast.messsage_type", "messageType", base.DEC)
+
+-- HELLO fields
+udp_port = ProtoField.uint16("cs168snowcast.udp_port", "udpPort", base.DEC)
+-- SET_STATION fields
+station_number = ProtoField.uint16("cs168snowcast.station_number", "stationNumber", base.DEC)
+-- WELCOME fields
+num_stations = ProtoField.uint16("cs168snowcast.num_stations", "numStations", base.DEC)
+-- ANNOUNCE fields
+song_name_size = ProtoField.uint8("cs168snowcast.song_name_size", "songnameSize", base.DEC)
+song_name = ProtoField.string("cs168snowcast.song_name", "songname")
+-- INVALID_COMMAND fields
+reply_string_size = ProtoField.uint8("cs168snowcast.reply_string_size", "replyStringSize", base.DEC)
+reply_string = ProtoField.string("cs168snowcast.reply_string", "replyString")
+
+snowcast_protocol.fields = {
+  message,
+  udp_port,
+  station_number,
+  num_stations,
+  song_name_size,
+  song_name,
+  reply_string_size,
+  reply_string
+}
+
+function snowcast_protocol.dissector(buffer, pinfo, tree)
+  length = buffer:len()
+  if length == 0 then return end
+
+  pinfo.cols.protocol = snowcast_protocol.name
+
+  local subtree = tree:add(snowcast_protocol, buffer(), "Snowcast Protocol Data")
+
+  local packet_len = buffer:reported_length_remaining()
+
+  local message_num = buffer(0, 1):uint()
+  local message_name = get_message_name(message_num)
+
+  -- Add command ID and name
+  subtree:add(message, buffer(0, 1)):append_text(" (" .. message_name .. ") ")
+
+  -- Clear any existing info in the info column so the TCP stuff info isn't in the way
+  pinfo.cols.info = ""
+
+  pinfo.cols.info:append("Snowcast " .. message_name)
+
+  if message_num == 0 then
+    -- Handling HELLO command
+    local udpPort = buffer(1, 2):uint()
+    subtree:add(udp_port, buffer(1, 2))
+    pinfo.cols.info:append(" (UDP Port: " .. udpPort .. ") ")
+  elseif message_num == 1 then
+    -- Handling SET_STATION command
+    local stationNumber = buffer(1, 2):uint()
+    subtree:add(station_number, buffer(1, 2))
+    pinfo.cols.info:append(" (Station Number: " .. stationNumber .. ") ")
+  elseif message_num == 2 then
+    -- Handling WELCOME reply
+    local numStations = buffer(1, 2):uint()
+    subtree:add(num_stations, buffer(1, 2))
+    pinfo.cols.info:append(" (Station Number: " .. numStations .. ") ")
+  elseif message_num == 3 then
+    -- Handling ANNOUNCE reply
+    local songnameSize = buffer(1, 1):uint()
+    subtree:add(reply_string_size, buffer(1, 1))
+
+    local songname = buffer(2, songnameSize):string()
+    subtree:add(reply_string, buffer(2, songnameSize))
+
+    pinfo.cols.info:append(" (Song Name [" .. songnameSize .. " bytes]: " .. songname .. ") ")
+  elseif message_num == 4 then
+    -- Handling INVALID_COMMAND reply
+    local replyStringSize = buffer(1, 1):uint()
+    subtree:add(reply_string_size, buffer(1, 1))
+
+    local replyString = buffer(2, replyStringSize):string()
+    subtree:add(reply_string, buffer(2, replyStringSize))
+
+    pinfo.cols.info:append(" (Reply String [" .. replyStringSize .. " bytes]: " .. replyString .. ") ")
+  end
+end
+
+function get_message_name(message_num)
+  local message_name = "UNNOWN"
+
+  if message_num == 0 then
+    message_name = "HELLO"
+  elseif message_num == 1 then
+    message_name = "SET_STATION"
+  elseif message_num == 2 then
+    message_name = "WELCOME REPLY"
+  elseif message_num == 3 then
+    message_name = "ANNOUNCE REPLY"
+  elseif message_num == 4 then
+    message_name = "INVALID_COMMAND REPLY"
+  end
+
+  return message_name
+end
+
+local tcp_port = DissectorTable.get("tcp.port")
+tcp_port:add(16800, snowcast_protocol)