netlink 与 socket
netlink对socket函数的实现(v2.6.18)应用层调用：skfd = socket(PF_NETLINK, SOCK_RAW, NL_IMP2);/net/socket.c:中有一个全局变量,它存储协议族：static struct net_proto_family *net_families[NPROTO]; struct net_proto_family {
