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packet lib: convert ip to use the checksum helper function

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Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
This commit is contained in:
FUJITA Tomonori 2012-08-27 11:37:30 +09:00
parent 2814763bb8
commit 1241dafde4
1 changed files with 2 additions and 13 deletions
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15
ryu/lib/packet/ipv4.py
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@ -15,6 +15,7 @@
import struct
from . import packet_base
from . import packet_utils
from . import udp
from ryu.ofproto import inet
@ -56,18 +57,6 @@ class ipv4(packet_base.PacketBase):
return msg, ipv4.get_packet_type(proto)
@staticmethod
def carry_around_add(a, b):
c = a + b
return (c & 0xffff) + (c >> 16)
def checksum(self, data):
s = 0
for i in range(0, len(data), 2):
w = data[i] + (data[i + 1] << 8)
s = self.carry_around_add(s, w)
return ~s & 0xffff
def serialize(self, payload, prev):
hdr = bytearray().zfill(self.header_length * 4)
version = self.version << 4 | self.header_length
@ -77,7 +66,7 @@ class ipv4(packet_base.PacketBase):
struct.pack_into(ipv4._PACK_STR, hdr, 0, version, self.tos,
self.total_length, self.identification, flags,
self.ttl, self.proto, 0, self.src, self.dst)
self.csum = self.checksum(hdr)
self.csum = packet_utils.checksum(hdr)
struct.pack_into('H', hdr, 10, self.csum)
return hdr