docs: def ifadd(self, iff, addr):
          """
          Add an interface 'iff' with provided address into routing table.
  
          Ex: ifadd('eth0', '2001:bd8:cafe:1::1/64') will add following entry into  # noqa: E501
              Scapy6 internal routing table:
  
              Destination           Next Hop  iface  Def src @           Metric
              2001:bd8:cafe:1::/64  ::        eth0   2001:bd8:cafe:1::1  1
  
              prefix length value can be omitted. In that case, a value of 128
              will be used.
          """
          addr, plen = (addr.split("/") + ["128"])[:2]
          addr = in6_ptop(addr)
          plen = int(plen)
          naddr = inet_pton(socket.AF_INET6, addr)
          nmask = in6_cidr2mask(plen)
          prefix = inet_ntop(socket.AF_INET6, in6_and(nmask, naddr))
          self.invalidate_cache()
          self.routes.append((prefix, plen, '::', iff, [addr], 1))