#print(addr, data)
ip = IP(data)
ip_len = ip.get_size()
tcp = TCP(data[ip_len:])
if tcp.get_th_dport() == 1234:
print('state', state)
#buf = tcp.get_packet()
#print([hex(n)[2:] for n in buf])
print(tcp, tcp.get_th_seq(), tcp.get_th_ack())
if state == 0:
ip, tcp = reply(ip, tcp)
tcp.set_th_ack(tcp.get_th_seq() + 1)
tcp.set_th_seq(0)
#print('###', tcp.get_th_seq())
tcp.set_ACK()
tcp.calculate_checksum()
buf = ip.get_packet()
print(tcp, tcp.get_th_seq(), tcp.get_th_ack())
server.sendto(buf, ('127.0.0.1', 0))
state = 1
elif state == 1:
if tcp.get_SYN() or not tcp.get_ACK():
break
print('connected...')
state = 2
elif state == 2:
if tcp.get_FIN():
ip, tcp = reply(ip, tcp)
tcp.set_th_ack(tcp.get_th_seq() + data_len)
tcp.set_th_seq(1)
tcp.reset_FIN()
