[Python] add option in tcp with scapy

Upon the receive of a TCP ACK (with option experiment) like this



I want to generate a TCP SYN+ACK (with option experiment and Fast Open Cookie) as indicated below



I want to generate the TCP SYN+ACK with scapy so I added

So I added 254 : ("RFC3692-style Experiment","!HHH") in the /usr/share/pyshared/scapy/layers/inet.py like this

TCPOptions = (
{ 0 : ("EOL",None),
1 : ("NOP",None),
2 : ("MSS","!H"),
3 : ("WScale","!B"),
4 : ("SAckOK",None),
5 : ("SAck","!"),
8 : ("Timestamp","!II"),
14 : ("AltChkSum","!BH"),
15 : ("AltChkSumOpt",None),
25 : ("Mood","!p"),
254 : ("Experiment","!HHHH")
},
{ "EOL":0,
"NOP":1,
"MSS":2,
"WScale":3,
"SAckOK":4,
"SAck":5,
"Timestamp":8,
"AltChkSum":14,
"AltChkSumOpt":15,
"Mood":25,
"Experiment":254
} )


And upon the receive of the TCP ACK (with experiment option), I executhe the following scapy function:

TCP_SYNACK=TCP(sport=Ddport, dport=Ssport, flags="SA", seq=SeqNr, ack=AckNr, options=[('Experiment',0xf989,0xcafe,0x0102,0x0002),('NOP',0),('NOP',0)])
ANSWER=sr1(ip/TCP_SYNACK)


But I got a python error. It looks like I made error in the definition of the option field in the TCP packet with scapy. What I m doing wron?

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