def _read_mptcp_prio(self, bits, size, kind):
"""Read Change Subflow Priority option.
Structure of ``MP_PRIO`` [RFC 6824]::
1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+---------------+---------------+-------+-----+-+--------------+
| Kind | Length |Subtype| |B| AddrID (opt) |
+---------------+---------------+-------+-----+-+--------------+
Arguments:
bits (str): 4-bit data (after subtype)
size (int): length of option
kind (Literal[30]): option kind value (Multipath TCP)
Returns:
DataType_TCP_Opt_REMOVE_ADDR: extracted Change Subflow Priority (``MP_PRIO``) option
"""
temp = self._read_unpack(1) if size else None
data = dict(
kind=kind,
length=size + 1,
subtype=MPTCPOption(4),
prio=dict(
backup=bool(int(bits[3])),
addr_id=temp,
),
)
return data
def _read_mptcp_join(self, bits, size, kind):
"""Read Join Connection option.
Arguments:
bits (str): 4-bit data (after subtype)
size (int): length of option
kind (Literal[30]): option kind value (Multipath TCP)
Returns:
DataType_TCP_Opt_MP_JOIN: extracted Join Connection (``MP_JOIN``) option
"""
if self._syn and self._ack: # MP_JOIN-SYN/ACK
return self._read_join_synack(bits, size, kind)
if self._syn and not self._ack: # MP_JOIN-SYN
return self._read_join_syn(bits, size, kind)
if not self._syn and self._ack: # MP_JOIN-ACK
return self._read_join_ack(bits, size, kind)
temp = self._read_fileng(size) # illegal MP_JOIN occurred
data = dict(
kind=kind,
length=size + 1,
subtype=MPTCPOption(1),
connection=None,
join=dict(
data=bytes(chr(int(bits[:4], base=2)), encoding='utf-8') + temp,
),
)
return data
def _read_mptcp_remove(self, bits, size, kind): # pylint: disable=unused-argument
"""Read Remove Address option.
Structure of ``REMOVE_ADDR`` [:rfc:`6824`]::
1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+---------------+---------------+-------+-------+---------------+
| Kind | Length = 3+n |Subtype|(resvd)| Address ID | ...
+---------------+---------------+-------+-------+---------------+
(followed by n-1 Address IDs, if required)
Arguments:
bits (str): 4-bit data (after subtype)
size (int): length of option
kind (Literal[30]): option kind value (Multipath TCP)
Returns:
DataType_TCP_Opt_REMOVE_ADDR: extracted Remove Address (``REMOVE_ADDR``) option
"""
adid = []
for _ in size:
adid.append(self._read_unpack(1))
data = dict(
kind=kind,
length=size + 1,
subtype=MPTCPOption(4),
removeaddr=dict(
addr_id=tuple(adid),
),
)
return data
def _read_mptcp_fastclose(self, bits, size, kind): # pylint: disable=unused-argument
"""Read Fast Close option.
Structure of ``MP_FASTCLOSE`` [RFC 6824]::
1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+---------------+---------------+-------+-----------------------+
| Kind | Length |Subtype| (reserved) |
+---------------+---------------+-------+-----------------------+
| Option Receiver's Key |
| (64 bits) |
| |
+---------------------------------------------------------------+
Arguments:
bits (str): 4-bit data (after subtype)
size (int): length of option
kind (Literal[30]): option kind value (Multipath TCP)
Returns:
DataType_TCP_Opt_MP_FAIL: extracted Fast Close (``MP_FASTCLOSE``) option
"""
resv = self._read_fileng(1) # pylint: disable=unused-variable
rkey = self._read_fileng(8)
data = dict(
kind=kind,
length=size + 1,
subtype=MPTCPOption(7),
fastclose=dict(rkey=rkey, ),
)
return data
def _read_mptcp_fail(self, bits, size, kind): # pylint: disable=unused-argument
"""Read Fallback option.
Structure of ``MP_FAIL`` [:rfc:`6824`]::
1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+---------------+---------------+-------+----------------------+
| Kind | Length=12 |Subtype| (reserved) |
+---------------+---------------+-------+----------------------+
| |
| Data Sequence Number (8 octets) |
| |
+--------------------------------------------------------------+
Arguments:
bits (str): 4-bit data (after subtype)
size (int): length of option
kind (Literal[30]): option kind value (Multipath TCP)
Returns:
DataType_TCP_Opt_MP_FAIL: extracted Fallback (``MP_FAIL``) option
"""
resv = self._read_fileng(1) # pylint: disable=unused-variable
dsn_ = self._read_unpack(8)
data = dict(
kind=kind,
length=size + 1,
subtype=MPTCPOption(6),
fail=dict(dsn=dsn_, ),
)
return data
def _read_mptcp_add(self, bits, size, kind):
"""Read Add Address option.
Structure of ``ADD_ADDR`` [:rfc:`6824`]::
1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+---------------+---------------+-------+-------+---------------+
| Kind | Length |Subtype| IPVer | Address ID |
+---------------+---------------+-------+-------+---------------+
| Address (IPv4 - 4 octets / IPv6 - 16 octets) |
+-------------------------------+-------------------------------+
| Port (2 octets, optional) |
+-------------------------------+
Arguments:
bits (str): 4-bit data (after subtype)
size (int): length of option
kind (Literal[30]): option kind value (Multipath TCP)
Returns:
DataType_TCP_Opt_ADD_ADDR: extracted Add Address (``ADD_ADDR``) option
Raises:
ProtocolError: If the option is malformed.
"""
vers = int(bits, base=2)
if vers == 4:
ip_l = 4
elif vers == 6:
ip_l = 16
else:
raise ProtocolError('[MP_TCP ADD_ADDR] malformed option')
adid = self._read_unpack(1)
ipad = self._read_fileng(ip_l)
pt_l = size - 1 - ip_l
port = self._read_unpack(2) if pt_l else None
data = dict(
kind=kind,
length=size + 1,
subtype=MPTCPOption(3),
add_addr=dict(
ip_ver=vers,
addrid=adid,
addr=ipaddress.ip_address(ipad),
port=port,
),
)
return data
def _read_mptcp_capable(self, bits, size, kind):
"""Read Multipath Capable option.
Structure of ``MP_CAPABLE`` [:rfc:`6824`]::
1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+---------------+---------------+-------+-------+---------------+
| Kind | Length |Subtype|Version|A|B|C|D|E|F|G|H|
+---------------+---------------+-------+-------+---------------+
| Option Sender's Key (64 bits) |
| |
| |
+---------------------------------------------------------------+
| Option Receiver's Key (64 bits) |
| (if option Length == 20) |
| |
+---------------------------------------------------------------+
Arguments:
bits (str): 4-bit data (after subtype)
size (int): length of option
kind (Literal[30]): option kind value (Multipath TCP)
Returns:
DataType_TCP_Opt_MP_CAPABLE: extracted Multipath Capable (``MP_CAPABLE``) option
"""
vers = int(bits, base=2)
bins = self._read_binary(1)
skey = self._read_unpack(8)
rkey = self._read_unpack(8) if size == 17 else None
data = dict(
kind=kind,
length=size + 1,
subtype=MPTCPOption(0),
capable=dict(
version=vers,
flags=dict(
req=bool(int(bins[0])),
ext=bool(int(bins[1])),
res=tuple(bool(int(bit)) for bit in bits[2:7]),
hsa=bool(int(bins[7])),
),
skey=skey,
rkey=rkey,
),
)
return data
def _read_join_synack(self, bits, size, kind):
"""Read Join Connection option for Responding SYN/ACK.
Structure of ``MP_JOIN-SYN/ACK`` [:rfc:`6824`]::
1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+---------------+---------------+-------+-----+-+---------------+
| Kind | Length = 16 |Subtype| |B| Address ID |
+---------------+---------------+-------+-----+-+---------------+
| |
| Sender's Truncated HMAC (64 bits) |
| |
+---------------------------------------------------------------+
| Sender's Random Number (32 bits) |
+---------------------------------------------------------------+
Arguments:
bits (str): 4-bit data (after subtype)
size (int): length of option
kind (Literal[30]): option kind value (Multipath TCP)
Returns:
DataType_TCP_Opt_MP_JOIN_SYNACK: extracted Join Connection (``MP_JOIN-SYN/ACK``)
option for Responding SYN/ACK
"""
adid = self._read_unpack(1)
hmac = self._read_fileng(8)
srno = self._read_unpack(4)
data = dict(
kind=kind,
length=size + 1,
subtype=MPTCPOption(1),
connection='SYN/ACK',
join=dict(
synack=dict(
backup=bool(int(bits[3])),
addr_id=adid,
hmac=hmac,
rand_num=srno,
),
),
)
return data
def _read_join_syn(self, bits, size, kind):
"""Read Join Connection option for Initial SYN.
Structure of ``MP_JOIN-SYN`` [:rfc:`6824`]::
1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+---------------+---------------+-------+-----+-+---------------+
| Kind | Length = 12 |Subtype| |B| Address ID |
+---------------+---------------+-------+-----+-+---------------+
| Receiver's Token (32 bits) |
+---------------------------------------------------------------+
| Sender's Random Number (32 bits) |
+---------------------------------------------------------------+
Arguments:
bits (str): 4-bit data (after subtype)
size (int): length of option
kind (Literal[30]): option kind value (Multipath TCP)
Returns:
DataType_TCP_Opt_MP_JOIN_SYN: extracted Join Connection (``MP_JOIN-SYN``) option for Initial SYN
"""
adid = self._read_unpack(1)
rtkn = self._read_unpack(4)
srno = self._read_unpack(4)
data = dict(
kind=kind,
length=size + 1,
subtype=MPTCPOption(1),
connection='SYN',
join=dict(
syn=dict(
backup=bool(int(bits[3])),
addr_id=adid,
token=rtkn,
rand_num=srno,
),
),
)
return data
def _read_join_ack(self, bits, size, kind): # pylint: disable=unused-argument
"""Read Join Connection option for Third ACK.
Structure of ``MP_JOIN-ACK`` [:rfc:`6824`]::
1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+---------------+---------------+-------+-----------------------+
| Kind | Length = 24 |Subtype| (reserved) |
+---------------+---------------+-------+-----------------------+
| |
| |
| Sender's HMAC (160 bits) |
| |
| |
+---------------------------------------------------------------+
Arguments:
bits (str): 4-bit data (after subtype)
size (int): length of option
kind (Literal[30]): option kind value (Multipath TCP)
Returns:
DataType_TCP_Opt_MP_JOIN_ACK: extracted Join Connection (``MP_JOIN-ACK``)
option for Third ACK
"""
temp = self._read_fileng(20)
data = dict(
kind=kind,
length=size + 1,
subtype=MPTCPOption(1),
connection='ACK',
join=dict(
ack=dict(
hmac=temp,
),
),
)
return data
def _read_mode_mptcp(self, size, kind):
"""Read Multipath TCP option.
Structure of ``MP-TCP`` [:rfc:`6824`]::
1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+---------------+---------------+-------+-----------------------+
| Kind | Length |Subtype| |
+---------------+---------------+-------+ |
| Subtype-specific data |
| (variable length) |
+---------------------------------------------------------------+
Arguments:
size (int): length of option
kind (Literal[30]): option kind value (Multipath TCP)
Returns:
DataType_TCP_Opt_MPTCP: extracted Multipath TCP (``MP-TCP``) option
"""
bins = self._read_binary(1)
subt = int(bins[:4], base=2) # subtype number
bits = bins[4:] # 4-bit data
dlen = size - 1 # length of remaining data
# fetch subtype-specific data
func = mptcp_opt.get(subt)
if func is None: # if subtype not exist, directly read all data
temp = self._read_fileng(dlen)
data = dict(
kind=kind,
length=size,
subtype=MPTCPOption.get(subt),
data=bytes(chr(int(bits[:4], base=2)), encoding='utf-8') +
temp,
)
else: # fetch corresponding subtype data dict
data = func(self, bits, dlen, kind)
return data
def _read_mptcp_dss(self, bits, size, kind):
"""Read Data Sequence Signal (Data ACK and Data Sequence Mapping) option.
Structure of ``DSS`` [:rfc:`6824`]::
1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+---------------+---------------+-------+----------------------+
| Kind | Length |Subtype| (reserved) |F|m|M|a|A|
+---------------+---------------+-------+----------------------+
| |
| Data ACK (4 or 8 octets, depending on flags) |
| |
+--------------------------------------------------------------+
| |
| Data sequence number (4 or 8 octets, depending on flags) |
| |
+--------------------------------------------------------------+
| Subflow Sequence Number (4 octets) |
+-------------------------------+------------------------------+
| Data-Level Length (2 octets) | Checksum (2 octets) |
+-------------------------------+------------------------------+
Arguments:
bits (str): 4-bit data (after subtype)
size (int): length of option
kind (Literal[30]): option kind value (Multipath TCP)
Returns:
DataType_TCP_Opt_DSS: extracted Data Sequence Signal (``DSS``) option
"""
bits = self._read_binary(1)
mflg = 8 if int(bits[4]) else 4
Mflg = bool(int(bits[5]))
aflg = 8 if int(bits[6]) else 4
Aflg = bool(int(bits[7]))
ack_ = self._read_unpack(aflg) if Aflg else None
dsn_ = self._read_unpack(mflg) if Mflg else None
ssn_ = self._read_unpack(4) if Mflg else None
dll_ = self._read_unpack(2) if Mflg else None
chk_ = self._read_fileng(2) if Mflg else None
data = dict(
kind=kind,
length=size + 1,
subtype=MPTCPOption(2),
dss=dict(
flags=dict(
fin=bool(int(bits[3])),
dsn_len=mflg,
data_pre=Mflg,
ack_len=aflg,
ack_pre=Aflg,
),
ack=ack_,
dsn=dsn_,
ssn=ssn_,
dl_len=dll_,
checksum=chk_,
),
)
return data
