diff options
Diffstat (limited to 'resources/libraries/python')
| -rw-r--r-- | resources/libraries/python/PacketVerifier.py | 24 |
1 files changed, 23 insertions, 1 deletions
diff --git a/resources/libraries/python/PacketVerifier.py b/resources/libraries/python/PacketVerifier.py index 9af14e3dce..45fab6a7c6 100644 --- a/resources/libraries/python/PacketVerifier.py +++ b/resources/libraries/python/PacketVerifier.py @@ -73,7 +73,7 @@ from scapy.all import Ether, ARP, Packet from scapy.layers.inet6 import IPv6 __all__ = ['RxQueue', 'TxQueue', 'Interface', 'create_gratuitous_arp_request', - 'auto_pad'] + 'auto_pad', 'checksum_equal'] # TODO: http://stackoverflow.com/questions/320232/ensuring-subprocesses-are-dead-on-exiting-python-program @@ -305,3 +305,25 @@ def auto_pad(packet): padded += ('\0' * (60 - len(padded))) return padded + +def checksum_equal(chksum1, chksum2): + """Compares two checksums in one's complement notation. + + Checksums to be compared are calculated as 16 bit one's complement of the + one's complement sum of 16 bit words of some buffer. + In one's complement notation 0x0000 (positive zero) and 0xFFFF + (negative zero) are equivalent. + + :param chksum1: First checksum. + :param chksum2: Second checksum. + :type chksum1: uint16 + :type chksum2: uint16 + + :return: True if checksums are equivalent, False otherwise. + :rtype: boolean + """ + if chksum1 == 0xFFFF: + chksum1 = 0 + if chksum2 == 0xFFFF: + chksum2 = 0 + return chksum1 == chksum2 |