#include <linux/mutex.h>
  #include <linux/socket.h>
  #include <linux/skbuff.h>
  #include <net/netlink.h>
  #include <net/net_namespace.h>
  #include <linux/module.h>

  #include <linux/rtnetlink.h>
  #include <net/sock.h>

  
  #include <linux/inet_diag.h>
  #include <linux/sock_diag.h>
  
  static struct sock_diag_handler *sock_diag_handlers[AF_MAX];
  static int (*inet_rcv_compat)(struct sk_buff *skb, struct nlmsghdr *nlh);
  static DEFINE_MUTEX(sock_diag_table_mutex);

  int sock_diag_check_cookie(void *sk, __u32 *cookie)
  {
  	if ((cookie[0] != INET_DIAG_NOCOOKIE ||
  	     cookie[1] != INET_DIAG_NOCOOKIE) &&
  	    ((u32)(unsigned long)sk != cookie[0] ||
  	     (u32)((((unsigned long)sk) >> 31) >> 1) != cookie[1]))
  		return -ESTALE;
  	else
  		return 0;
  }
  EXPORT_SYMBOL_GPL(sock_diag_check_cookie);
  
  void sock_diag_save_cookie(void *sk, __u32 *cookie)
  {
  	cookie[0] = (u32)(unsigned long)sk;
  	cookie[1] = (u32)(((unsigned long)sk >> 31) >> 1);
  }
  EXPORT_SYMBOL_GPL(sock_diag_save_cookie);

  int sock_diag_put_meminfo(struct sock *sk, struct sk_buff *skb, int attrtype)
  {
  	__u32 *mem;
  
  	mem = RTA_DATA(__RTA_PUT(skb, attrtype, SK_MEMINFO_VARS * sizeof(__u32)));
  
  	mem[SK_MEMINFO_RMEM_ALLOC] = sk_rmem_alloc_get(sk);
  	mem[SK_MEMINFO_RCVBUF] = sk->sk_rcvbuf;
  	mem[SK_MEMINFO_WMEM_ALLOC] = sk_wmem_alloc_get(sk);
  	mem[SK_MEMINFO_SNDBUF] = sk->sk_sndbuf;
  	mem[SK_MEMINFO_FWD_ALLOC] = sk->sk_forward_alloc;
  	mem[SK_MEMINFO_WMEM_QUEUED] = sk->sk_wmem_queued;
  	mem[SK_MEMINFO_OPTMEM] = atomic_read(&sk->sk_omem_alloc);
  
  	return 0;
  
  rtattr_failure:
  	return -EMSGSIZE;
  }
  EXPORT_SYMBOL_GPL(sock_diag_put_meminfo);

  void sock_diag_register_inet_compat(int (*fn)(struct sk_buff *skb, struct nlmsghdr *nlh))
  {
  	mutex_lock(&sock_diag_table_mutex);
  	inet_rcv_compat = fn;
  	mutex_unlock(&sock_diag_table_mutex);
  }
  EXPORT_SYMBOL_GPL(sock_diag_register_inet_compat);
  
  void sock_diag_unregister_inet_compat(int (*fn)(struct sk_buff *skb, struct nlmsghdr *nlh))
  {
  	mutex_lock(&sock_diag_table_mutex);
  	inet_rcv_compat = NULL;
  	mutex_unlock(&sock_diag_table_mutex);
  }
  EXPORT_SYMBOL_GPL(sock_diag_unregister_inet_compat);
  
  int sock_diag_register(struct sock_diag_handler *hndl)
  {
  	int err = 0;

  	if (hndl->family >= AF_MAX)

  		return -EINVAL;
  
  	mutex_lock(&sock_diag_table_mutex);
  	if (sock_diag_handlers[hndl->family])
  		err = -EBUSY;
  	else
  		sock_diag_handlers[hndl->family] = hndl;
  	mutex_unlock(&sock_diag_table_mutex);
  
  	return err;
  }
  EXPORT_SYMBOL_GPL(sock_diag_register);
  
  void sock_diag_unregister(struct sock_diag_handler *hnld)
  {
  	int family = hnld->family;

  	if (family >= AF_MAX)

  		return;
  
  	mutex_lock(&sock_diag_table_mutex);
  	BUG_ON(sock_diag_handlers[family] != hnld);
  	sock_diag_handlers[family] = NULL;
  	mutex_unlock(&sock_diag_table_mutex);
  }
  EXPORT_SYMBOL_GPL(sock_diag_unregister);
  
  static inline struct sock_diag_handler *sock_diag_lock_handler(int family)
  {
  	if (sock_diag_handlers[family] == NULL)
  		request_module("net-pf-%d-proto-%d-type-%d", PF_NETLINK,

  				NETLINK_SOCK_DIAG, family);

  
  	mutex_lock(&sock_diag_table_mutex);
  	return sock_diag_handlers[family];
  }
  
  static inline void sock_diag_unlock_handler(struct sock_diag_handler *h)
  {
  	mutex_unlock(&sock_diag_table_mutex);
  }
  
  static int __sock_diag_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
  {
  	int err;
  	struct sock_diag_req *req = NLMSG_DATA(nlh);
  	struct sock_diag_handler *hndl;
  
  	if (nlmsg_len(nlh) < sizeof(*req))
  		return -EINVAL;
  
  	hndl = sock_diag_lock_handler(req->sdiag_family);
  	if (hndl == NULL)
  		err = -ENOENT;
  	else
  		err = hndl->dump(skb, nlh);
  	sock_diag_unlock_handler(hndl);
  
  	return err;
  }
  
  static int sock_diag_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
  {
  	int ret;
  
  	switch (nlh->nlmsg_type) {
  	case TCPDIAG_GETSOCK:
  	case DCCPDIAG_GETSOCK:
  		if (inet_rcv_compat == NULL)
  			request_module("net-pf-%d-proto-%d-type-%d", PF_NETLINK,

  					NETLINK_SOCK_DIAG, AF_INET);

  
  		mutex_lock(&sock_diag_table_mutex);
  		if (inet_rcv_compat != NULL)
  			ret = inet_rcv_compat(skb, nlh);
  		else
  			ret = -EOPNOTSUPP;
  		mutex_unlock(&sock_diag_table_mutex);
  
  		return ret;
  	case SOCK_DIAG_BY_FAMILY:
  		return __sock_diag_rcv_msg(skb, nlh);
  	default:
  		return -EINVAL;
  	}
  }
  
  static DEFINE_MUTEX(sock_diag_mutex);
  
  static void sock_diag_rcv(struct sk_buff *skb)
  {
  	mutex_lock(&sock_diag_mutex);
  	netlink_rcv_skb(skb, &sock_diag_rcv_msg);
  	mutex_unlock(&sock_diag_mutex);
  }
  
  struct sock *sock_diag_nlsk;
  EXPORT_SYMBOL_GPL(sock_diag_nlsk);
  
  static int __init sock_diag_init(void)
  {
  	sock_diag_nlsk = netlink_kernel_create(&init_net, NETLINK_SOCK_DIAG, 0,
  					sock_diag_rcv, NULL, THIS_MODULE);
  	return sock_diag_nlsk == NULL ? -ENOMEM : 0;
  }
  
  static void __exit sock_diag_exit(void)
  {
  	netlink_kernel_release(sock_diag_nlsk);
  }
  
  module_init(sock_diag_init);
  module_exit(sock_diag_exit);
  MODULE_LICENSE("GPL");
  MODULE_ALIAS_NET_PF_PROTO(PF_NETLINK, NETLINK_SOCK_DIAG);