bgp.py 文件源码

def encode_attr_mp_nexthop(nexthop):
    """ Encode string nexthop into a BGP MP_REACH attribute TLV

        A modified MP_REACH attribute that includes only the next hop info (per MRT RFC6396)
        This includes only the next hop address lenght (1 octet) and the next-hop

        :param nexthop:      String value for the next-hop

        :return: BGP attribute TLV ready to be written
    """
    # Set afi and length based on nexthop address
    if ':' in nexthop:
        nh_len = 16
        afi = socket.AF_INET6
    else:
        nh_len = 4
        afi = socket.AF_INET

    return ATTR_TYPE_MP_REACH + pack('!BB', nh_len + 1, nh_len) + socket.inet_pton(afi, nexthop)