carp.py 文件源码

def build_hmac_sha1(pkt, pw = '\0' * 20, ip4l = [], ip6l = []):
    if not pkt.haslayer(CARP):
        return None 

    p = pkt[CARP]
    h = hmac.new(pw, digestmod = hashlib.sha1)
    # XXX: this is a dirty hack. it needs to pack version and type into a single 8bit field
    h.update('\x21')
    # XXX: mac addy if different from special link layer. comes before vhid
    h.update(struct.pack('!B', p.vhid))

    sl = []
    for i in ip4l:
        # sort ips from smallest to largest
        sl.append(inet_aton(i))
    sl.sort()

    for i in sl:
        h.update(i)

    # XXX: do ip6l sorting

    return h.digest()