def interp(plugin, nuin):
family = nuin.value(0)
res_id = nuin.value(1);
pattrs = (ctypes.POINTER(mnl.Attr) * (nfqnl.NFQA_MAX + 1)).from_buffer(nuin.value(2))
ph = pattrs[nfqnl.NFQA_PACKET_HDR].contents.get_payload_as(nfqnl.NfqnlMsgPacketHdr)
packet_id = socket.ntohl(ph.packet_id)
log.info("res_id: %d, qid: %d", res_id, packet_id)
if pattrs[nfqnl.NFQA_PAYLOAD]:
nfq_payload = pattrs[nfqnl.NFQA_PAYLOAD].contents
ip = IP(bytes(nfq_payload.get_payload_v()))
if ip[ICMP].seq % 2 == 0:
# wrong data byte ...
ip[ICMP].payload = bytes(ip[ICMP].payload).replace(b'!', b'@')
# (truncated)
# ip[ICMP].payload = bytes(ip[ICMP].payload)[:4]
# no error but ``bytes from'' is differ a little?
# ip[ICMP].payload = bytes(ip[ICMP].payload) + (b'0' * 8192)
ip[ICMP].chksum = 0 # NEED THIS
ip[ICMP].chksum = utils.checksum(bytes(ip[ICMP]))
nfq_send_repeat(res_id, packet_id, 10, (ctypes.c_ubyte * len(ip)).from_buffer(bytearray(bytes(ip))))
else:
nfq_send_accept(res_id, packet_id)
return nurs.NURS_RET_OK
def post_build(self, p, pay):
# type: (bytes, bytes) -> bytes
p += pay
if self.chksum_present and self.chksum is None:
c = checksum(p)
p = p[:4] + chb((c >> 8) & 0xff) + chb(c & 0xff) + p[6:]
return p
def post_build(self, p, pay):
# See <http://tools.ietf.org/html/rfc5613>
p += pay
if self.checksum is None:
# Checksum is calculated without authentication data
# Algorithm is the same as in IP()
ck = checksum(p[:16] + p[24:])
p = p[:12] + struct.pack("!H", ck) + p[14:]
return p
def guess_payload_class(self, payload): """Implements guess_payload_class to identify MPLS packets with internal Ethernet header""" # If bottom of stack is zero, the next layer is MPLS for sure. if self.s == 0: return MPLS # If checksum is ok, then we have a correct IP header after MPLS labels. elif checksum(payload[:20]) == 0: return IP # If checksum is nok, then we (almost) certainly have an Ethernet header after MPLS. else: return Ether
def run(self):
"""
Infinite loop that gets packets from the packet queue and checks if the packet is a handover test packet.
If it is it inserts the VNF id in the packet an recalculates the UDP/TCP checksum.
Then the packet is forwarded to the output socket.
:return:
"""
while True:
buf = self.packet_queue.get()
eth_type = struct.unpack_from('!H', buf, 12)[0]
if eth_type == 0x800:
proto = buf[23]
if proto == '\x11':
# UDP
buf = buf[:50] + struct.pack("!H", self.vnf_id) + buf[52:]
psdhdr = buf[26:34] + struct.pack("!HH", 0x11,
len(buf) - 34)
ck = checksum(psdhdr + buf[34:40] + '\x00\x00' + buf[42:])
if ck == 0:
ck = 0xffff
buf = buf[:40] + chr(ck >> 8) + chr(ck & 0xff) + buf[42:]
elif proto == '\x06' and len(buf) >= 84:
# TCP
buf_len = len(buf)
offset = 66
while offset < buf_len:
buf = buf[:offset + 8] + struct.pack(
"!H", self.vnf_id) + buf[offset + 10:]
pkt_len = struct.unpack("!H", buf[offset + 16:offset +
18])[0]
offset += pkt_len
psdhdr = buf[26:34] + struct.pack("!HH", 0x06,
len(buf) - 34)
ck = checksum(psdhdr + buf[34:50] + '\x00\x00' + buf[52:])
buf = buf[:50] + chr(ck >> 8) + chr(ck & 0xff) + buf[52:]
self.out_socket.send(buf)
def post_build(self, p, pay):
# See <http://tools.ietf.org/html/rfc5613>
p += pay
if self.chksum is None:
if self.authtype == 2:
ck = 0 # Crypto, see RFC 2328, D.4.3
else:
# Checksum is calculated without authentication data
# Algorithm is the same as in IP()
ck = checksum(p[:16] + p[24:])
p = p[:12] + struct.pack("!H", ck) + p[14:]
# TODO: Handle Crypto: Add message digest (RFC 2328, D.4.3)
return p
def post_build(self, p, pay):
# See <http://tools.ietf.org/html/rfc5613>
p += pay
if self.chksum is None:
if self.authtype == 2:
ck = 0 # Crypto, see RFC 2328, D.4.3
else:
# Checksum is calculated without authentication data
# Algorithm is the same as in IP()
ck = checksum(p[:16] + p[24:])
p = p[:12] + struct.pack("!H", ck) + p[14:]
# TODO: Handle Crypto: Add message digest (RFC 2328, D.4.3)
return p
def post_build(self, p, pay):
"""Called implicitly before a packet is sent to compute and place IGMP checksum. # noqa: E501
Parameters:
self The instantiation of an IGMP class
p The IGMP message in hex in network byte order
pay Additional payload for the IGMP message
"""
p += pay
if self.chksum is None:
ck = checksum(p)
p = p[:2] + chb(ck >> 8) + chb(ck & 0xff) + p[4:]
return p
def post_build(self, p, pay):
"""Called implicitly before a packet is sent to compute and place IGMP checksum. # noqa: E501
Parameters:
self The instantiation of an IGMP class
p The IGMP message in hex in network byte order
pay Additional payload for the IGMP message
"""
p += pay
if self.chksum is None:
ck = checksum(p)
p = p[:2] + chb(ck >> 8) + chb(ck & 0xff) + p[4:]
return p
def post_build(self, p, pay):
ihl = self.ihl
p += b"\0" * ((-len(p)) % 4) # pad IP options if needed
if ihl is None:
ihl = len(p) // 4
p = chb(((self.version & 0xf) << 4) | ihl & 0x0f) + p[1:]
if self.len is None:
tmp_len = len(p) + len(pay)
p = p[:2] + struct.pack("!H", tmp_len) + p[4:]
if self.chksum is None:
ck = checksum(p)
p = p[:10] + chb(ck >> 8) + chb(ck & 0xff) + p[12:]
return p + pay
def post_build(self, p, pay):
"""
Called implicitly before a packet is sent to compute and
place PIM checksum.
Parameters:
self The instantiation of an PIMv2Hdr class
p The PIMv2Hdr message in hex in network byte order
pay Additional payload for the PIMv2Hdr message
"""
p += pay
if self.chksum is None:
ck = checksum(p)
p = p[:2] + struct.pack("!H", ck) + p[4:]
return p
def post_build(self, p, pay):
'''Called implicitly before a packet is sent to compute and place IGMPv3 checksum.
Parameters:
self The instantiation of an IGMPv3 class
p The IGMPv3 message in hex in network byte order
pay Additional payload for the IGMPv3 message
'''
p += pay
if self.type in [0, 0x31, 0x32, 0x22]: # for these, field is reserved (0)
p = p[:1]+chr(0)+p[2:]
if self.chksum is None:
ck = checksum(p)
p = p[:2]+chr(ck>>8)+chr(ck&0xff)+p[4:]
return p
def post_build(self, pkt, payload):
pkt += payload
# max_resp_code field is reserved (0)
if self.type in [IGMP_TYPE_V3_MEMBERSHIP_REPORT,]:
mrc = 0
else:
mrc = self.encode_float(self.max_resp_code)
pkt = pkt[:1] + chr(mrc) + pkt[2:]
if self.checksum is None:
chksum = checksum(pkt)
pkt = pkt[:2] + chr(chksum >> 8) + chr(chksum & 0xff) + pkt[4:]
return pkt
def post_build(self, pkt, payload):
pkt += payload
# max_resp_code field is reserved (0)
if self.type in [
IGMP_TYPE_V3_MEMBERSHIP_REPORT,
]:
mrc = 0
else:
mrc = self.encode_float(self.max_resp_code)
pkt = pkt[:1] + chr(mrc) + pkt[2:]
if self.checksum is None:
chksum = checksum(pkt)
pkt = pkt[:2] + chr(chksum >> 8) + chr(chksum & 0xff) + pkt[4:]
return pkt
def mini_ip_checksum(raw_mini_ip):
"""Returns mini_ip checksum."""
return checksum(raw_mini_ip)
def post_build(self, p, pay):
p += pay
if self.chksum is None:
ck = checksum(p)
p = p[:2] + chb(ck >> 8) + chb(ck & 0xff) + p[4:]
return p
def post_build(self, pkt, pay):
if self.chksum is None:
pkt = pkt[:6] + struct.pack("!H", checksum(pkt)) + pkt[8:]
return pkt
def post_build(self, p, pay):
p += pay
if self.chksum_present and self.chksum is None:
c = checksum(p)
p = p[:4] + chb((c >> 8) & 0xff) + chb(c & 0xff) + p[6:]
return p
def post_build(self, pkt, pay):
if self.chksum == None:
pkt = pkt[:6] + struct.pack("!H", checksum(pkt)) + pkt[8:]
return pkt
def post_build(self, p, pay):
p += pay
if self.chksum is None:
c = checksum(p)
p = struct.pack("!H", c) + p[2:]
return p
def post_build(self, p, pay):
p += pay
if self.chksum is None:
c = checksum(p)
p = struct.pack("!H", c) + p[2:]
return p
def post_build(self, p, pay):
p += pay
if self.chksum is None:
c = checksum(p)
p = p[:2]+chr((c>>8)&0xff)+chr(c&0xff)+p[4:]
return p
