def get_raw_packet(self, ip_pseudo_header):
""" Get packet in raw format ready to be processed by lower level protocol """
self.tcp_cksum = inet_cksum.compute_cksum(ip_pseudo_header +
self.raw_packet)
return self.raw_packet
def get_raw_packet(self):
""" Get packet in raw format ready to be processed by lower level protocol """
self.ipv4_cksum = inet_cksum.compute_cksum(self.raw_header +
self.raw_options)
return self.raw_packet
def validate_cksum(self, ip_pseudo_header):
""" Validate packet checksum """
# from binascii import hexlify
# print(hexlify(self.raw_packet))
return not bool(
inet_cksum.compute_cksum(ip_pseudo_header + self.raw_packet))
def validate_cksum(self, ip_pseudo_header):
""" Validate packet checksum """
# Return valid checksum if checksum is not used
if not self.udp_cksum:
return True
return not bool(
inet_cksum.compute_cksum(ip_pseudo_header + self.raw_packet))
def handle_ip4_fragmentation(ip4_packet_rx):
""" Check if packet is fragmented """
# Check if IP packet is a first fragment
if ip4_packet_rx.ip4_frag_offset == 0 and ip4_packet_rx.ip4_frag_mf:
ip4_fragments[ip4_packet_rx.ip4_packet_id] = {}
ip4_fragments[ip4_packet_rx.ip4_packet_id][ip4_packet_rx.ip4_frag_offset] = ip4_packet_rx.raw_data
return None
# Check if IP packet is one of middle fragments
if ip4_packet_rx.ip4_frag_offset != 0 and ip4_packet_rx.ip4_frag_mf:
# Check if packet is part of existing fagment flow
if ip4_fragments.get(ip4_packet_rx.ip4_packet_id, None):
ip4_fragments[ip4_packet_rx.ip4_packet_id][ip4_packet_rx.ip4_frag_offset] = ip4_packet_rx.raw_data
return None
# Check if IP packet is last fragment
if ip4_packet_rx.ip4_frag_offset != 0 and not ip4_packet_rx.ip4_frag_mf:
# Check if packet is part of existing fagment flow
if ip4_fragments.get(ip4_packet_rx.ip4_packet_id, None):
ip4_fragments[ip4_packet_rx.ip4_packet_id][ip4_packet_rx.ip4_frag_offset] = ip4_packet_rx.raw_data
raw_data = b""
for offset in sorted(ip4_fragments[ip4_packet_rx.ip4_packet_id]):
raw_data += ip4_fragments[ip4_packet_rx.ip4_packet_id][offset]
# Craft complete IP packet based on last fragment for further processing
ip4_packet_rx.ip4_frag_mf = False
ip4_packet_rx.ip4_frag_offset = 0
ip4_packet_rx.ip4_plen = ip4_packet_rx.ip4_hlen + len(raw_data)
ip4_packet_rx.ip4_cksum = 0
ip4_packet_rx.ip4_cksum = inet_cksum.compute_cksum(ip4_packet_rx.raw_header)
ip4_packet_rx.raw_data = raw_data
return ip4_packet_rx
def validate_cksum(self):
""" Validate packet checksum """
return not bool(inet_cksum.compute_cksum(self.raw_packet))
def validate_cksum(self, ip_pseudo_header):
""" Validate packet checksum """
return not bool(
inet_cksum.compute_cksum(ip_pseudo_header + self.raw_packet))
def validate_cksum(self):
""" Validate packet checksum """
return not bool(inet_cksum.compute_cksum(self.raw_header + self.raw_options))