Question

我有一个客户端服务器协议，其工作方式如下客户端发送带有服务器id的udp广播（到固定端口）服务器接收数据报，如果匹配了他的id，他就向客户端发送他正在收听的端口然后客户端打开到该端口的TCP连接我正在Lua为这件事写一个Wireshark解剖器，我需要动态设置tcp连接的端口（事先我不知道服务器侦听的女巫端口）。

我尝试过类似的东西：

-- 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()
        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

我缺少什么？
提前致谢

Answer 1

此处介绍的机制有效。问题是端口号取自错误的字节（来自缓冲区（4,2）而不是缓冲区（7,2））。

在lua中编写wireshark解剖器并将其设置在动态端口上

1 个答案: