Writing a wireshark dissector in lua and setting it on a dynamic port
-- declare our protocol
myproto_udp_proto = Proto("myproto_UDP","myproto UDP Protocol")
myproto_tcp_proto = Proto("myproto_TCP","myproto TCP Protocol")
-- create a function to dissect it
function myproto_tcp_proto.dissector(buffer,pinfo,tree)
pinfo.cols.protocol = "myproto TCP"
local subtree = tree:add(myproto_tcp_proto,buffer(),"myproto TCP Protocol Data")
if buffer(0,2):uint() == 0xF00D then
subtree:add(buffer(0,2),"Magic(F00D)")
else
subtree:add(buffer(0,2),"Bad Magic")
end
end
function myproto_udp_proto.dissector(buffer,pinfo,tree)
pinfo.cols.protocol = "myproto UDP"
local subtree = tree:add(myproto_udp_proto,buffer(),"myproto UDP Protocol Data")
if buffer(0,2):uint() == 0xF00D then
subtree:add(buffer(0,2),"Magic(F00D)")
local command;
local port = -1;
if buffer(2,1):uint() == 01 then
command = "Searching for server"
elseif buffer(2,1):uint() == 02 then
command = "I'm server"
port = buffer(7,2):uint开发者_开发知识库()
else
command = "unknown";
end
subtree:add(buffer(2,1),command)
subtree:add(buffer(3,4),"Server id: " .. buffer(3,4):uint())
if port ~= -1 then
subtree:add(buffer(7,2),"Server listening port: " .. buffer(7,2):uint())
subtree:add(buffer(9,4),"check bytes")
myproto_tcp_init(port)
end
else
subtree:add(buffer(0,2),"Bad Magic")
end
end
-- load the udp.port table
udp_table = DissectorTable.get("udp.port")
-- register our protocol to handle udp port 1338
udp_table:add(1338,myproto_udp_proto)
function myproto_tcp_init(port)
-- load the tcp.port table
tcp_table = DissectorTable.get("tcp.port")
-- register our protocol to handle tcp port !DYNAMIC!
tcp_table:add(port,myproto_tcp_proto)
end
What I'm missing?
Thanks in advanceThe mechanism presented here works. The problem was that the port number was taken from the wrong bytes (from buffer(4,2) instead of buffer(7,2)).
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