def compose_options(options):
tcpsoption = ""
avail_opt_len = 40
for opt in options:
if opt[0] == 'NOP':
if avail_opt_len < 1:
break
nop = tcplib.create_nop()
tcpsoption += nop
avail_opt_len -= 1
continue
if opt[0] == 'MSS':
if avail_opt_len < 4:
break
mssoption = tcplib.create_mss(opt[1])
tcpsoption += mssoption
avail_opt_len -= 4
continue
if opt[0] == 'WSCALE':
if avail_opt_len < 3:
break
wsoption = tcplib.create_winscale(opt[1])
tcpsoption += wsoption
avail_opt_len -= 3
continue
if opt[0] == 'SACKOK':
if avail_opt_len < 2:
break
sackok_option = tcplib.create_sackok()
tcpsoption += sackok_option
avail_opt_len -= 2
continue
if opt[0] == 'TIMESTAMP':
if avail_opt_len < 10:
break
tsoption = tcplib.create_timestamp(opt[1], opt[2])
tcpsoption += tsoption
avail_opt_len -= 10
continue
if opt[0] == 'MP_CAPABLE':
length = 20 if opt[3] is not None else 12
if avail_opt_len < length:
break
mpcap_option = tcplib.create_mpcapable(opt[1], opt[2], opt[3])
tcpsoption += mpcap_option
avail_opt_len -= length
continue
if opt[0] == 'MP_DSS':
length = (14 if opt[6] is not None else 0) + (4 if opt[4] is not None else 0) + \
(4 if opt[4] is not None and opt[3] else 0) + (4 if opt[5] else 0)
if avail_opt_len < length:
break
dss_option = tcplib.create_mpdss(opt[1], opt[2], opt[3], opt[4], \
opt[5], opt[6], opt[7])
tcpsoption += dss_option
avail_opt_len -= length
continue
if opt[0] == 'MP_ACK':
if avail_opt_len < 10:
break
dataack_option = tcplib.create_mpack(opt[1])
tcpsoption += dataack_option
avail_opt_len -= 10
continue
tcpsoption += tcplib.check_padding(tcpsoption)
return tcpsoption
def compose_options(options):
tcpsoption = ""
avail_opt_len = 40
for opt in options:
if opt[0] == 'NOP':
if avail_opt_len < 1:
break
nop = tcplib.create_nop()
tcpsoption += nop
avail_opt_len -= 1
continue
if opt[0] == 'MSS':
if avail_opt_len < 4:
break
mssoption = tcplib.create_mss(opt[1])
tcpsoption += mssoption
avail_opt_len -= 4
continue
if opt[0] == 'WSCALE':
if avail_opt_len < 3:
break
wsoption = tcplib.create_winscale(opt[1])
tcpsoption += wsoption
avail_opt_len -= 3
continue
if opt[0] == 'SACKOK':
if avail_opt_len < 2:
break
sackok_option = tcplib.create_sackok()
tcpsoption += sackok_option
avail_opt_len -= 2
continue
if opt[0] == 'TIMESTAMP':
if avail_opt_len < 10:
break
tsoption = tcplib.create_timestamp(opt[1], opt[2])
tcpsoption += tsoption
avail_opt_len -= 10
continue
if opt[0] == 'MP_CAPABLE':
if avail_opt_len < 12:
break
mpcap_option = tcplib.create_mpcapable(opt[1], opt[2])
tcpsoption += mpcap_option
avail_opt_len -= 12
continue
if opt[0] == 'MP_DATA':
if avail_opt_len < 16:
break
# (Dsn (8 Byte), Dlen (2 Byte), Ssn(4 Byte))
dsn_option = tcplib.create_mpdata(opt[1], opt[2], opt[3])
tcpsoption += dsn_option
avail_opt_len -= 16
continue
if opt[0] == 'MP_ACK':
if avail_opt_len < 10:
break
dataack_option = tcplib.create_mpack(opt[1])
tcpsoption += dataack_option
avail_opt_len -= 10
continue
tcpsoption += tcplib.check_padding(tcpsoption)
return tcpsoption
tcpwindow -= sigval
TSval = rcv_syntsecr
tcpsoption = mssoption + wsoption + sackokoption
tsecr = tcplib.unpack_timestamp(tcpoption[idx+2:idx+10])[0]
tcpsoption += tcplib.create_timestamp(TSval, tsecr)
elif kind == tcplib.TO_MP_CAPABLE and optlen == 12:
if datalen is 0:
mssoption = tcplib.create_mss(MSSval-2)
wsoption = tcplib.create_winscale(WSval-2)
tcpwindow -= 2
tsoption = tcplib.create_timestamp(TSval-2, tsecr)
tcpsoption = mssoption + wsoption + sackokoption + tsoption
tcpsoption += tcpoption[idx:idx+12]
elif kind == tcplib.TO_MP_DATA and optlen == 16:
dsn = tcplib.unpack_mpdata(tcpoption[idx+2:idx+16])
tcpsoption += tcplib.create_mpack(dsn[0]+dsn[1])
idx += optlen
olen -= optlen
tcpflag = tcplib.TH_ACK
if tcph.flag & tcplib.TH_SYN:
tcpflag |= tcplib.TH_SYN
datalen = 1
if tcph.flag & tcplib.TH_FIN:
datalen = 1
if tcpflag & tcplib.TH_SYN or tcpflag & tcplib.TH_FIN or datalen > 0:
if not tcpflag & tcplib.TH_SYN:
tcpseqno = tcph.ackno
tcpackno = tcph.seqno + datalen
# special hack parse