Ideas for nodejs raw socket helpers

gistfile1.js

var socket = raw.createSocket({
    protocol: raw.Protocol.TCP
});

/*
 * calling new raw.packet will compute automagicaly ip header, pseudo header and tcp header,
 * based on tcp headers and ip headers options passed in args
 *
 * it return an object with functions:
 * - send(socket,options,callback)     --> see below in this page
 * - getBuffer()                       --> return the computed buffer, usefull for make TESTS !! :)
 */

var packet = new raw.packet({
    tcph:{
        sport:null,                         // optional, source port, if null, a random port will be set
        dport:81,                           // mandatory, dst port
        seq:null,                           // optional, sequence number, if null given, a random one will be set
        ack_seq:null,                       // internal (?): next packet sequence number, default 0
        doff:0,                             // internal (?): data offset, can be computed automagicaly ?
        flag:raw.Flags.SYN,                 // mandatory, FIN,SYN,RST,PSH,ACK,URG
        window: 1024,                       // optional, window size, defaut 1024 ?
        ptr_urg:0,                          // optional, default 0
        options:{
            mss:1460                        // optional, default 1460 ?
        }
    },
    iph:{
        ihl:0,                              // internal, header length
        checksum:0,                         // internal, checksum,
        protocol:raw.Protocol.TCP,          // internal, default is createSocket protocol option ?       
        frag_off:???,                       // don't know what it is (fragment offset field)
        version:raw.AddressFamily.IPv4,     // optional, default IPv4
        tos:0,                              // optional, type of service,
        id:0                                // optional, random by default
        ttl:64                              // optional, default 64 ?
        saddr:'127.0.0.1',                  // optional, 127.0.0.1  default ?
        daddr:null                          // optional, if null, take sendPacket first arg
    }
});


var options = {
    target:'127.0.0.1',
    timeout:1000                            // how many ms to wait for any the first packet emited by the target
}

var cb = function(err,buffer) {
    /* err can be :
        - timeout
        - bad packet ?
            (
            should be great to check checksums 
            before sending the packet, for testing purpose
            )
    */
}

var onAck = function(data) {
    // data is the received packet
}

var onRst = function(data) {
    // data is the received packet
}


// new packet.send function :
packet.send(socket,options,cb);



// theses callbacks should only be fired if 
// packets are emited by the target
// and are valids packet (check checksums, size, ...)

packet.on('ack',onAck);
packet.on('rst',onRst);