ID_MASK
return (old_ids >> shift) & ID_MASK;
old_id = (old_ids >> shift) & ID_MASK;
new_ids = (old_ids & ~(ID_MASK << shift));
(ntohl(nla_get_be32(data[IFLA_GRE_IKEY])) & ~ID_MASK))
(ntohl(nla_get_be32(data[IFLA_GRE_OKEY])) & ~ID_MASK))
(ntohl(nla_get_be32(data[IFLA_GRE_IKEY])) & ~ID_MASK))
(ntohl(nla_get_be32(data[IFLA_GRE_OKEY])) & ~ID_MASK))