pulsar.lua

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      http://www.apache.org/licenses/LICENSE-2.0

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--  [TOTAL_SIZE] [CMD_SIZE][CMD]
--  [TOTAL_SIZE] [CMD_SIZE][CMD] [MAGIC_NUMBER][CHECKSUM] [METADATA_SIZE][METADATA] [PAYLOAD]
local protobuf_dissector = Dissector.get("protobuf")
local pulsar_protocol = Proto("Pulsar", "pulsar.proto.BaseCommand")

-- Create protobuf dissector based on TCP.
-- The TCP dissector will parse tvb as pulsar format
-- @param name  The name of the new dissector.
-- @param desc  The description of the new dissector.
-- @param msgtype  Message type. This must be the root message defined in your .proto file.
local function get_pulsar_length(tvb, pinfo, tree)
    local totalLength = tvb(0, 4):uint()
    return totalLength + 4
end
local function dissect_pulsar_pdu(tvb, pinfo, tree)
    pinfo.cols.protocol = "Pulsar"
    local pduLength = tvb:len()
    local offset = 4
    local commandLenth = tvb(offset, 4):uint()
    offset = offset + 4
    local subtree = tree:add(pulsar_protocol, tvb())
    pinfo.private["pb_msg_type"] = "message,pulsar.proto.BaseCommand"
    pcall(Dissector.call, protobuf_dissector, tvb(offset, commandLenth):tvb(), pinfo, subtree)
    offset = offset + commandLenth
    if offset == pduLength then
        return
    end
    local checkSum = tvb(offset, 2):bytes():tohex()
    -- has not checksum ,but has payload
    if checkSum ~= '0E01' then
        local metaSize = tvb(offset, 4):uint()
        pinfo.private["pb_msg_type"] = "message,pulsar.proto.MessageMetadata"
        offset = offset + 4
        pcall(Dissector.call, protobuf_dissector, tvb(offset, metaSize):tvb(), pinfo, subtree)
        offset = offset + metaSize
    end
    -- has checksum , has payload
    if checkSum == '0E01' then
        offset = offset + 6 -- magic and checksum
        local metaSize = tvb(offset, 4):uint()
        pinfo.private["pb_msg_type"] = "message,pulsar.proto.MessageMetadata"
        offset = offset + 4
        pcall(Dissector.call, protobuf_dissector, tvb(offset, metaSize):tvb(), pinfo, subtree)
        offset = offset + metaSize
    end
end

pulsar_protocol.dissector = function(tvb, pinfo, tree)
    local bytes_consumed = 0
    dissect_tcp_pdus(tvb, tree, 4, get_pulsar_length, dissect_pulsar_pdu)
    bytes_consumed = tvb:len()
    return bytes_consumed
end

pulsar_protocol.prefs.port = Pref.uint("Pulsar TCP port", 6650)
local tcp_port = DissectorTable.get("tcp.port")
tcp_port:add(pulsar_protocol.prefs.port, pulsar_protocol)