ippkts.py 文件源码

def __calc_udp_csum(saddr, daddr, udp_data, is_ipv6=False):
    size = len(udp_data)
    seq = [
        saddr, daddr, b'\x00\x11',
        utils.number2bytes(size, 2),
        udp_data,
    ]

    if is_ipv6:
        size += 24
    else:
        size += 12

    if 0 != size % 2:
        seq.append(b"\0")
        size += 1

    data = b"".join(seq)
    csum = socket.htons(fn_utils.calc_csum(data, size))

    # csum = __calc_checksum(data, size)
    # import socket
    # print(csum,socket.htons(csum_t))

    if csum == 0: return 0xffff

    return csum