Add Wireshark NMRP dissector

diff --git a/wireshark-nmrp.lua b/wireshark-nmrp.lua
new file mode 100644 (file)
index 0000000..6463ccf
--- /dev/null
+++ b/wireshark-nmrp.lua
@@ -0,0 +1,103 @@
+--
+-- NMRP dissector for Wireshark
+--
+-- Copyright (C) 2016 Joseph C. Lehner
+--
+-- Licensed under the GNU GPL 3.0
+--
+
+nmrp_proto = Proto("nmrp", "NMRP")
+
+src_f = ProtoField.string("nmrp.src", "Source")
+dst_f = ProtoField.string("nmrp.dst", "Destination")
+code_f = ProtoField.uint8("nmrp.code", "Code", base.HEX)
+id_f = ProtoField.uint8("nmrp.id", "ID", base.HEX)
+reserved_f = ProtoField.uint16("nmrp.reserved", "Reserved", base.HEX)
+len_f = ProtoField.uint16("nmrp.len", "Length")
+data_f = ProtoField.bytes("nmrp.opt", "Options")
+opt_type_f = ProtoField.uint16("nmrp.opt.type", "Option", base.HEX)
+opt_len_f = ProtoField.uint16("nmrp.opt.len", "Length")
+opt_data_f = ProtoField.bytes("nmrp.opt.data", "Data")
+
+nmrp_proto.fields = {
+       code_f, reserved_f, len_f, data_f, id_f, opt_type_f, opt_len_f, opt_data_f
+}
+
+function nmrp_code(code)
+       if code == 1 then return { "ADVERTISE", "Advertise" }
+       elseif code == 2 then return { "CONF_REQ", "Configuration Request" }
+       elseif code == 3 then return { "CONF_ACK", "Configuration" }
+       elseif code == 4 then return { "CLOSE_REQ", "Close Request" }
+       elseif code == 5 then return { "CLOSE_ACK", "Close Acknowledgement" }
+       elseif code == 6 then return { "KEEP_ALIVE_REQ", "Keep-alive Request" }
+       elseif code == 7 then return { "KEEP_ALIVE_ACK", "Keep-alive Acknowledgement" }
+       elseif code == 16 then return { "TFTP_UL_REQ", "Upload Request" }
+       else return { "#" .. code, "Unknown Opcode " .. code }
+       end
+end
+
+function nmrp_opt(opt)
+       if opt == 0x01 then return "Magic"
+       elseif opt == 0x02 then return "IP Configuration"
+       elseif opt == 0x04 then return "Region"
+       elseif opt == 0x0101 then return "Update Firmware"
+       elseif opt == 0x0102 then return "Update String Table"
+       elseif opt == 0x0181 then return "Filename"
+       else return "#" .. opt
+       end
+end
+
+function nmrp_dissect_opt(opt, buffer, tree)
+       if buffer:len() <= 4 then
+               return
+       end
+
+       if opt == 0x01 or opt == 0x0181 then
+               tree:add(buffer(4), "Value: " .. buffer(4):string())
+       elseif opt == 0x02 then
+               tree:add(buffer(4, 4), "Address: " .. tostring(buffer(4, 4):ipv4()))
+               tree:add(buffer(8, 4), "Netmask: " .. tostring(buffer(8, 4):ipv4()))
+       else
+               tree:add(opt_len_f, buffer(2, 2))
+               tree:add(opt_data_f, buffer(4, buffer:len() - 4))
+       end
+end
+
+
+function nmrp_proto.dissector(buffer, pinfo, tree)
+       pinfo.cols.protocol = "NMRP"
+
+       local code = buffer(2, 1)
+       local len = buffer(4, 2)
+
+       pinfo.cols.info = nmrp_code(code:uint())[2]
+
+       local subtree = tree:add(nmrp_proto, buffer(0))
+       subtree:add(code_f, code):append_text(" - " .. nmrp_code(code:uint())[2])
+       subtree:add(id_f, buffer(3, 1))
+       subtree:add(len_f, len)
+       subtree:add(reserved_f, buffer(0, 2))
+
+       local databuf = buffer(6, len:uint() - 6)
+
+       while databuf:len() > 0 do
+               local opt = databuf(0, 2):uint()
+               local optlen = databuf(2, 2):uint()
+
+               if databuf:len() < optlen then
+                       break
+               end
+
+               local optitem = subtree:add(opt_type_f, databuf(0, 2)):append_text(" - " .. nmrp_opt(opt))
+               nmrp_dissect_opt(opt, databuf(0, optlen), optitem)
+
+               if databuf:len() > optlen then
+                       databuf = databuf(optlen)
+               else
+                       break
+               end
+       end
+end
+
+eth_table = DissectorTable.get("ethertype")
+eth_table:add(0x0912, nmrp_proto)