def _compute_checksum_ipv4(self, ip4, xdata):
if ip4 is None:
return 0
xhdr = struct.pack('!IIxBHHHHH', int(ip4.srcip), int(ip4.dstip),
ip4.protocol.value, self._len, self.srcport,
self.dstport, self._len, 0)
return checksum(xhdr + xdata)
def _compute_checksum_ipv4(self, ip4, xdata):
if ip4 is None:
return 0
phdr = struct.pack('!IIxBH', int(ip4.srcip), int(ip4.dstip),
ip4.protocol.value, self._len)
tcphdr = self._make_header(0)
return checksum(phdr + tcphdr + xdata)
def _compute_checksum_ipv4(self, ip4, xdata):
if ip4 is None:
return 0
phdr = struct.pack('!IIxBH', int(ip4.srcip), int(ip4.dstip),
ip4.protocol.value, self._len)
tcphdr = self._make_header(0)
return checksum(phdr + tcphdr + xdata)
def _compute_checksum_ipv4(self, ip4, xdata):
if ip4 is None:
return 0
xhdr = struct.pack('!IIxBHHHHH', int(ip4.srcip), int(ip4.dstip),
ip4.protocol.value, self._len,
self.srcport, self.dstport, self._len, 0)
return checksum(xhdr + xdata)
def _compute_checksum(self):
# FIXME: computed on IPv6 pseudoheader + full mobility header (starting with ext header)
# pseudoheader: srcaddr(16),dstaddr(16),len of mobility header (4), 000 next header(4)
self._checksum = 0
exthdr = self.to_bytes(computecsum=False)
self._checksum = checksum(
struct.pack('16s16sIxxxB', self._srcip.packed, self._dstip.packed,
len(exthdr), IPProtocol.IPv6Mobility.value) + exthdr)
return self._checksum
def checksum(self):
data = struct.pack(IPv4._PACKFMT,
(4 << 4) + self.hl, self.tos,
self._totallen, self.ipid,
(self.flags.value << 13) | self.fragment_offset,
self.ttl,
self.protocol.value, 0, self.src.packed, self.dst.packed)
data += self._options.to_bytes()
self._csum = checksum(data, 0)
return self._csum
def checksum(self):
self._checksum = checksum(b''.join(
(struct.pack(ICMP._PACKFMT, self._type.value, self._code.value,
0), self._icmpdata.to_bytes())))
return self._checksum
