/*
   * NETLINK      Kernel-user communication protocol.
   *

   * 		Authors:	Alan Cox <alan@lxorguk.ukuu.org.uk>

   * 				Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>

   * 				Patrick McHardy <kaber@trash.net>

   *
   *		This program is free software; you can redistribute it and/or
   *		modify it under the terms of the GNU General Public License
   *		as published by the Free Software Foundation; either version
   *		2 of the License, or (at your option) any later version.

   *

   * Tue Jun 26 14:36:48 MEST 2001 Herbert "herp" Rosmanith
   *                               added netlink_proto_exit
   * Tue Jan 22 18:32:44 BRST 2002 Arnaldo C. de Melo <acme@conectiva.com.br>
   * 				 use nlk_sk, as sk->protinfo is on a diet 8)

   * Fri Jul 22 19:51:12 MEST 2005 Harald Welte <laforge@gnumonks.org>
   * 				 - inc module use count of module that owns
   * 				   the kernel socket in case userspace opens
   * 				   socket of same protocol
   * 				 - remove all module support, since netlink is
   * 				   mandatory if CONFIG_NET=y these days

   */

  #include <linux/module.h>

  #include <linux/capability.h>

  #include <linux/kernel.h>
  #include <linux/init.h>

  #include <linux/signal.h>
  #include <linux/sched.h>
  #include <linux/errno.h>
  #include <linux/string.h>
  #include <linux/stat.h>
  #include <linux/socket.h>
  #include <linux/un.h>
  #include <linux/fcntl.h>
  #include <linux/termios.h>
  #include <linux/sockios.h>
  #include <linux/net.h>
  #include <linux/fs.h>
  #include <linux/slab.h>

  #include <linux/uaccess.h>

  #include <linux/skbuff.h>
  #include <linux/netdevice.h>
  #include <linux/rtnetlink.h>
  #include <linux/proc_fs.h>
  #include <linux/seq_file.h>

  #include <linux/notifier.h>
  #include <linux/security.h>
  #include <linux/jhash.h>
  #include <linux/jiffies.h>
  #include <linux/random.h>
  #include <linux/bitops.h>
  #include <linux/mm.h>
  #include <linux/types.h>

  #include <linux/audit.h>

  #include <linux/mutex.h>

  #include <linux/vmalloc.h>

  #include <linux/if_arp.h>

  #include <linux/rhashtable.h>

  #include <asm/cacheflush.h>

  #include <linux/hash.h>

  #include <linux/genetlink.h>

  #include <linux/net_namespace.h>

  #include <linux/nospec.h>

  #include <net/net_namespace.h>

  #include <net/sock.h>
  #include <net/scm.h>

  #include <net/netlink.h>

  #include "af_netlink.h"

  struct listeners {
  	struct rcu_head		rcu;
  	unsigned long		masks[0];

  };

  /* state bits */

  #define NETLINK_S_CONGESTED		0x0

  static inline int netlink_is_kernel(struct sock *sk)

  {

  	return nlk_sk(sk)->flags & NETLINK_F_KERNEL_SOCKET;

  }

  struct netlink_table *nl_table __read_mostly;

  EXPORT_SYMBOL_GPL(nl_table);

  
  static DECLARE_WAIT_QUEUE_HEAD(nl_table_wait);

  static struct lock_class_key nlk_cb_mutex_keys[MAX_LINKS];
  
  static const char *const nlk_cb_mutex_key_strings[MAX_LINKS + 1] = {
  	"nlk_cb_mutex-ROUTE",
  	"nlk_cb_mutex-1",
  	"nlk_cb_mutex-USERSOCK",
  	"nlk_cb_mutex-FIREWALL",
  	"nlk_cb_mutex-SOCK_DIAG",
  	"nlk_cb_mutex-NFLOG",
  	"nlk_cb_mutex-XFRM",
  	"nlk_cb_mutex-SELINUX",
  	"nlk_cb_mutex-ISCSI",
  	"nlk_cb_mutex-AUDIT",
  	"nlk_cb_mutex-FIB_LOOKUP",
  	"nlk_cb_mutex-CONNECTOR",
  	"nlk_cb_mutex-NETFILTER",
  	"nlk_cb_mutex-IP6_FW",
  	"nlk_cb_mutex-DNRTMSG",
  	"nlk_cb_mutex-KOBJECT_UEVENT",
  	"nlk_cb_mutex-GENERIC",
  	"nlk_cb_mutex-17",
  	"nlk_cb_mutex-SCSITRANSPORT",
  	"nlk_cb_mutex-ECRYPTFS",
  	"nlk_cb_mutex-RDMA",
  	"nlk_cb_mutex-CRYPTO",
  	"nlk_cb_mutex-SMC",
  	"nlk_cb_mutex-23",
  	"nlk_cb_mutex-24",
  	"nlk_cb_mutex-25",
  	"nlk_cb_mutex-26",
  	"nlk_cb_mutex-27",
  	"nlk_cb_mutex-28",
  	"nlk_cb_mutex-29",
  	"nlk_cb_mutex-30",
  	"nlk_cb_mutex-31",
  	"nlk_cb_mutex-MAX_LINKS"
  };

  static int netlink_dump(struct sock *sk);

  static void netlink_skb_destructor(struct sk_buff *skb);

  /* nl_table locking explained:

   * Lookup and traversal are protected with an RCU read-side lock. Insertion

   * and removal are protected with per bucket lock while using RCU list

   * modification primitives and may run in parallel to RCU protected lookups.
   * Destruction of the Netlink socket may only occur *after* nl_table_lock has
   * been acquired * either during or after the socket has been removed from
   * the list and after an RCU grace period.

   */

  DEFINE_RWLOCK(nl_table_lock);
  EXPORT_SYMBOL_GPL(nl_table_lock);

  static atomic_t nl_table_users = ATOMIC_INIT(0);

  #define nl_deref_protected(X) rcu_dereference_protected(X, lockdep_is_held(&nl_table_lock));

  static BLOCKING_NOTIFIER_HEAD(netlink_chain);

  static DEFINE_SPINLOCK(netlink_tap_lock);
  static struct list_head netlink_tap_all __read_mostly;

  static const struct rhashtable_params netlink_rhashtable_params;

  static inline u32 netlink_group_mask(u32 group)

  {
  	return group ? 1 << (group - 1) : 0;
  }

  static struct sk_buff *netlink_to_full_skb(const struct sk_buff *skb,
  					   gfp_t gfp_mask)
  {
  	unsigned int len = skb_end_offset(skb);
  	struct sk_buff *new;
  
  	new = alloc_skb(len, gfp_mask);
  	if (new == NULL)
  		return NULL;
  
  	NETLINK_CB(new).portid = NETLINK_CB(skb).portid;
  	NETLINK_CB(new).dst_group = NETLINK_CB(skb).dst_group;
  	NETLINK_CB(new).creds = NETLINK_CB(skb).creds;

  	skb_put_data(new, skb->data, len);

  	return new;
  }

  int netlink_add_tap(struct netlink_tap *nt)
  {
  	if (unlikely(nt->dev->type != ARPHRD_NETLINK))
  		return -EINVAL;
  
  	spin_lock(&netlink_tap_lock);
  	list_add_rcu(&nt->list, &netlink_tap_all);
  	spin_unlock(&netlink_tap_lock);

  	__module_get(nt->module);

  
  	return 0;
  }
  EXPORT_SYMBOL_GPL(netlink_add_tap);

  static int __netlink_remove_tap(struct netlink_tap *nt)

  {
  	bool found = false;
  	struct netlink_tap *tmp;
  
  	spin_lock(&netlink_tap_lock);
  
  	list_for_each_entry(tmp, &netlink_tap_all, list) {
  		if (nt == tmp) {
  			list_del_rcu(&nt->list);
  			found = true;
  			goto out;
  		}
  	}
  
  	pr_warn("__netlink_remove_tap: %p not found
  ", nt);
  out:
  	spin_unlock(&netlink_tap_lock);

  	if (found)

  		module_put(nt->module);
  
  	return found ? 0 : -ENODEV;
  }

  
  int netlink_remove_tap(struct netlink_tap *nt)
  {
  	int ret;
  
  	ret = __netlink_remove_tap(nt);
  	synchronize_net();
  
  	return ret;
  }
  EXPORT_SYMBOL_GPL(netlink_remove_tap);

  static bool netlink_filter_tap(const struct sk_buff *skb)
  {
  	struct sock *sk = skb->sk;

  
  	/* We take the more conservative approach and
  	 * whitelist socket protocols that may pass.
  	 */
  	switch (sk->sk_protocol) {
  	case NETLINK_ROUTE:
  	case NETLINK_USERSOCK:
  	case NETLINK_SOCK_DIAG:
  	case NETLINK_NFLOG:
  	case NETLINK_XFRM:
  	case NETLINK_FIB_LOOKUP:
  	case NETLINK_NETFILTER:
  	case NETLINK_GENERIC:

  		return true;

  	}

  	return false;

  }

  static int __netlink_deliver_tap_skb(struct sk_buff *skb,
  				     struct net_device *dev)
  {
  	struct sk_buff *nskb;

  	struct sock *sk = skb->sk;

  	int ret = -ENOMEM;

  	if (!net_eq(dev_net(dev), sock_net(sk)))
  		return 0;

  	dev_hold(dev);

  	if (is_vmalloc_addr(skb->head))

  		nskb = netlink_to_full_skb(skb, GFP_ATOMIC);
  	else
  		nskb = skb_clone(skb, GFP_ATOMIC);

  	if (nskb) {
  		nskb->dev = dev;

  		nskb->protocol = htons((u16) sk->sk_protocol);

  		nskb->pkt_type = netlink_is_kernel(sk) ?
  				 PACKET_KERNEL : PACKET_USER;

  		skb_reset_network_header(nskb);

  		ret = dev_queue_xmit(nskb);
  		if (unlikely(ret > 0))
  			ret = net_xmit_errno(ret);
  	}
  
  	dev_put(dev);
  	return ret;
  }
  
  static void __netlink_deliver_tap(struct sk_buff *skb)
  {
  	int ret;
  	struct netlink_tap *tmp;

  	if (!netlink_filter_tap(skb))
  		return;

  	list_for_each_entry_rcu(tmp, &netlink_tap_all, list) {
  		ret = __netlink_deliver_tap_skb(skb, tmp->dev);
  		if (unlikely(ret))
  			break;
  	}
  }
  
  static void netlink_deliver_tap(struct sk_buff *skb)
  {
  	rcu_read_lock();
  
  	if (unlikely(!list_empty(&netlink_tap_all)))
  		__netlink_deliver_tap(skb);
  
  	rcu_read_unlock();
  }

  static void netlink_deliver_tap_kernel(struct sock *dst, struct sock *src,
  				       struct sk_buff *skb)
  {
  	if (!(netlink_is_kernel(dst) && netlink_is_kernel(src)))
  		netlink_deliver_tap(skb);
  }

  static void netlink_overrun(struct sock *sk)
  {
  	struct netlink_sock *nlk = nlk_sk(sk);

  	if (!(nlk->flags & NETLINK_F_RECV_NO_ENOBUFS)) {
  		if (!test_and_set_bit(NETLINK_S_CONGESTED,
  				      &nlk_sk(sk)->state)) {

  			sk->sk_err = ENOBUFS;
  			sk->sk_error_report(sk);
  		}
  	}
  	atomic_inc(&sk->sk_drops);
  }
  
  static void netlink_rcv_wake(struct sock *sk)
  {
  	struct netlink_sock *nlk = nlk_sk(sk);
  
  	if (skb_queue_empty(&sk->sk_receive_queue))

  		clear_bit(NETLINK_S_CONGESTED, &nlk->state);
  	if (!test_bit(NETLINK_S_CONGESTED, &nlk->state))

  		wake_up_interruptible(&nlk->wait);
  }

  static void netlink_skb_destructor(struct sk_buff *skb)
  {

  	if (is_vmalloc_addr(skb->head)) {

  		if (!skb->cloned ||
  		    !atomic_dec_return(&(skb_shinfo(skb)->dataref)))
  			vfree(skb->head);

  		skb->head = NULL;
  	}

  	if (skb->sk != NULL)
  		sock_rfree(skb);

  }
  
  static void netlink_skb_set_owner_r(struct sk_buff *skb, struct sock *sk)
  {
  	WARN_ON(skb->sk != NULL);
  	skb->sk = sk;
  	skb->destructor = netlink_skb_destructor;
  	atomic_add(skb->truesize, &sk->sk_rmem_alloc);
  	sk_mem_charge(sk, skb->truesize);
  }

  static void netlink_sock_destruct(struct sock *sk)

  {

  	struct netlink_sock *nlk = nlk_sk(sk);

  	if (nlk->cb_running) {

  		if (nlk->cb.done)
  			nlk->cb.done(&nlk->cb);

  		module_put(nlk->cb.module);
  		kfree_skb(nlk->cb.skb);

  	}

  	skb_queue_purge(&sk->sk_receive_queue);
  
  	if (!sock_flag(sk, SOCK_DEAD)) {

  		printk(KERN_ERR "Freeing alive netlink socket %p
  ", sk);

  		return;
  	}

  
  	WARN_ON(atomic_read(&sk->sk_rmem_alloc));

  	WARN_ON(refcount_read(&sk->sk_wmem_alloc));

  	WARN_ON(nlk_sk(sk)->groups);

  }

  static void netlink_sock_destruct_work(struct work_struct *work)
  {
  	struct netlink_sock *nlk = container_of(work, struct netlink_sock,
  						work);

  	sk_free(&nlk->sk);

  }

  /* This lock without WQ_FLAG_EXCLUSIVE is good on UP and it is _very_ bad on
   * SMP. Look, when several writers sleep and reader wakes them up, all but one

   * immediately hit write lock and grab all the cpus. Exclusive sleep solves
   * this, _but_ remember, it adds useless work on UP machines.
   */

  void netlink_table_grab(void)

  	__acquires(nl_table_lock)

  {

  	might_sleep();

  	write_lock_irq(&nl_table_lock);

  
  	if (atomic_read(&nl_table_users)) {
  		DECLARE_WAITQUEUE(wait, current);
  
  		add_wait_queue_exclusive(&nl_table_wait, &wait);

  		for (;;) {

  			set_current_state(TASK_UNINTERRUPTIBLE);
  			if (atomic_read(&nl_table_users) == 0)
  				break;

  			write_unlock_irq(&nl_table_lock);

  			schedule();

  			write_lock_irq(&nl_table_lock);

  		}
  
  		__set_current_state(TASK_RUNNING);
  		remove_wait_queue(&nl_table_wait, &wait);
  	}
  }

  void netlink_table_ungrab(void)

  	__releases(nl_table_lock)

  {

  	write_unlock_irq(&nl_table_lock);

  	wake_up(&nl_table_wait);
  }

  static inline void

  netlink_lock_table(void)
  {
  	/* read_lock() synchronizes us to netlink_table_grab */
  
  	read_lock(&nl_table_lock);
  	atomic_inc(&nl_table_users);
  	read_unlock(&nl_table_lock);
  }

  static inline void

  netlink_unlock_table(void)
  {
  	if (atomic_dec_and_test(&nl_table_users))
  		wake_up(&nl_table_wait);
  }

  struct netlink_compare_arg

  {

  	possible_net_t pnet;

  	u32 portid;
  };

  /* Doing sizeof directly may yield 4 extra bytes on 64-bit. */
  #define netlink_compare_arg_len \
  	(offsetof(struct netlink_compare_arg, portid) + sizeof(u32))

  
  static inline int netlink_compare(struct rhashtable_compare_arg *arg,
  				  const void *ptr)

  {

  	const struct netlink_compare_arg *x = arg->key;
  	const struct netlink_sock *nlk = ptr;

  	return nlk->portid != x->portid ||

  	       !net_eq(sock_net(&nlk->sk), read_pnet(&x->pnet));
  }
  
  static void netlink_compare_arg_init(struct netlink_compare_arg *arg,
  				     struct net *net, u32 portid)
  {
  	memset(arg, 0, sizeof(*arg));
  	write_pnet(&arg->pnet, net);
  	arg->portid = portid;

  }

  static struct sock *__netlink_lookup(struct netlink_table *table, u32 portid,
  				     struct net *net)

  {

  	struct netlink_compare_arg arg;

  	netlink_compare_arg_init(&arg, net, portid);
  	return rhashtable_lookup_fast(&table->hash, &arg,
  				      netlink_rhashtable_params);

  }

  static int __netlink_insert(struct netlink_table *table, struct sock *sk)

  {

  	struct netlink_compare_arg arg;

  	netlink_compare_arg_init(&arg, sock_net(sk), nlk_sk(sk)->portid);

  	return rhashtable_lookup_insert_key(&table->hash, &arg,
  					    &nlk_sk(sk)->node,
  					    netlink_rhashtable_params);

  }

  static struct sock *netlink_lookup(struct net *net, int protocol, u32 portid)

  {

  	struct netlink_table *table = &nl_table[protocol];
  	struct sock *sk;

  	rcu_read_lock();
  	sk = __netlink_lookup(table, portid, net);
  	if (sk)
  		sock_hold(sk);
  	rcu_read_unlock();

  	return sk;

  }

  static const struct proto_ops netlink_ops;

  static void
  netlink_update_listeners(struct sock *sk)
  {
  	struct netlink_table *tbl = &nl_table[sk->sk_protocol];

  	unsigned long mask;
  	unsigned int i;

  	struct listeners *listeners;
  
  	listeners = nl_deref_protected(tbl->listeners);
  	if (!listeners)
  		return;

  	for (i = 0; i < NLGRPLONGS(tbl->groups); i++) {

  		mask = 0;

  		sk_for_each_bound(sk, &tbl->mc_list) {

  			if (i < NLGRPLONGS(nlk_sk(sk)->ngroups))
  				mask |= nlk_sk(sk)->groups[i];
  		}

  		listeners->masks[i] = mask;

  	}
  	/* this function is only called with the netlink table "grabbed", which
  	 * makes sure updates are visible before bind or setsockopt return. */
  }

  static int netlink_insert(struct sock *sk, u32 portid)

  {

  	struct netlink_table *table = &nl_table[sk->sk_protocol];

  	int err;

  	lock_sock(sk);

  	err = nlk_sk(sk)->portid == portid ? 0 : -EBUSY;
  	if (nlk_sk(sk)->bound)

  		goto err;
  
  	err = -ENOMEM;

  	if (BITS_PER_LONG > 32 &&
  	    unlikely(atomic_read(&table->hash.nelems) >= UINT_MAX))

  		goto err;

  	nlk_sk(sk)->portid = portid;

  	sock_hold(sk);

  	err = __netlink_insert(table, sk);
  	if (err) {

  		/* In case the hashtable backend returns with -EBUSY
  		 * from here, it must not escape to the caller.
  		 */
  		if (unlikely(err == -EBUSY))
  			err = -EOVERFLOW;

  		if (err == -EEXIST)
  			err = -EADDRINUSE;

  		sock_put(sk);

  		goto err;

  	}

  	/* We need to ensure that the socket is hashed and visible. */
  	smp_wmb();
  	nlk_sk(sk)->bound = portid;

  err:

  	release_sock(sk);

  	return err;
  }
  
  static void netlink_remove(struct sock *sk)
  {

  	struct netlink_table *table;

  	table = &nl_table[sk->sk_protocol];

  	if (!rhashtable_remove_fast(&table->hash, &nlk_sk(sk)->node,
  				    netlink_rhashtable_params)) {

  		WARN_ON(refcount_read(&sk->sk_refcnt) == 1);

  		__sock_put(sk);
  	}

  	netlink_table_grab();

  	if (nlk_sk(sk)->subscriptions) {

  		__sk_del_bind_node(sk);

  		netlink_update_listeners(sk);
  	}

  	if (sk->sk_protocol == NETLINK_GENERIC)
  		atomic_inc(&genl_sk_destructing_cnt);

  	netlink_table_ungrab();
  }
  
  static struct proto netlink_proto = {
  	.name	  = "NETLINK",
  	.owner	  = THIS_MODULE,
  	.obj_size = sizeof(struct netlink_sock),
  };

  static int __netlink_create(struct net *net, struct socket *sock,

  			    struct mutex *cb_mutex, int protocol,
  			    int kern)

  {
  	struct sock *sk;
  	struct netlink_sock *nlk;

  
  	sock->ops = &netlink_ops;

  	sk = sk_alloc(net, PF_NETLINK, GFP_KERNEL, &netlink_proto, kern);

  	if (!sk)
  		return -ENOMEM;
  
  	sock_init_data(sock, sk);
  
  	nlk = nlk_sk(sk);

  	if (cb_mutex) {

  		nlk->cb_mutex = cb_mutex;

  	} else {

  		nlk->cb_mutex = &nlk->cb_def_mutex;
  		mutex_init(nlk->cb_mutex);

  		lockdep_set_class_and_name(nlk->cb_mutex,
  					   nlk_cb_mutex_keys + protocol,
  					   nlk_cb_mutex_key_strings[protocol]);

  	}

  	init_waitqueue_head(&nlk->wait);
  
  	sk->sk_destruct = netlink_sock_destruct;
  	sk->sk_protocol = protocol;
  	return 0;
  }

  static int netlink_create(struct net *net, struct socket *sock, int protocol,
  			  int kern)

  {
  	struct module *module = NULL;

  	struct mutex *cb_mutex;

  	struct netlink_sock *nlk;

  	int (*bind)(struct net *net, int group);
  	void (*unbind)(struct net *net, int group);

  	int err = 0;

  
  	sock->state = SS_UNCONNECTED;
  
  	if (sock->type != SOCK_RAW && sock->type != SOCK_DGRAM)
  		return -ESOCKTNOSUPPORT;

  	if (protocol < 0 || protocol >= MAX_LINKS)

  		return -EPROTONOSUPPORT;

  	protocol = array_index_nospec(protocol, MAX_LINKS);

  	netlink_lock_table();

  #ifdef CONFIG_MODULES

  	if (!nl_table[protocol].registered) {

  		netlink_unlock_table();

  		request_module("net-pf-%d-proto-%d", PF_NETLINK, protocol);

  		netlink_lock_table();

  	}

  #endif
  	if (nl_table[protocol].registered &&
  	    try_module_get(nl_table[protocol].module))
  		module = nl_table[protocol].module;

  	else
  		err = -EPROTONOSUPPORT;

  	cb_mutex = nl_table[protocol].cb_mutex;

  	bind = nl_table[protocol].bind;

  	unbind = nl_table[protocol].unbind;

  	netlink_unlock_table();

  	if (err < 0)
  		goto out;

  	err = __netlink_create(net, sock, cb_mutex, protocol, kern);

  	if (err < 0)

  		goto out_module;

  	local_bh_disable();

  	sock_prot_inuse_add(net, &netlink_proto, 1);

  	local_bh_enable();

  	nlk = nlk_sk(sock->sk);

  	nlk->module = module;

  	nlk->netlink_bind = bind;

  	nlk->netlink_unbind = unbind;

  out:
  	return err;

  out_module:
  	module_put(module);
  	goto out;

  }

  static void deferred_put_nlk_sk(struct rcu_head *head)
  {
  	struct netlink_sock *nlk = container_of(head, struct netlink_sock, rcu);

  	struct sock *sk = &nlk->sk;

  	kfree(nlk->groups);
  	nlk->groups = NULL;

  	if (!refcount_dec_and_test(&sk->sk_refcnt))

  		return;
  
  	if (nlk->cb_running && nlk->cb.done) {
  		INIT_WORK(&nlk->work, netlink_sock_destruct_work);
  		schedule_work(&nlk->work);
  		return;
  	}

  	sk_free(sk);

  }

  static int netlink_release(struct socket *sock)
  {
  	struct sock *sk = sock->sk;
  	struct netlink_sock *nlk;
  
  	if (!sk)
  		return 0;
  
  	netlink_remove(sk);

  	sock_orphan(sk);

  	nlk = nlk_sk(sk);

  	/*
  	 * OK. Socket is unlinked, any packets that arrive now
  	 * will be purged.
  	 */

  	/* must not acquire netlink_table_lock in any way again before unbind
  	 * and notifying genetlink is done as otherwise it might deadlock
  	 */
  	if (nlk->netlink_unbind) {
  		int i;
  
  		for (i = 0; i < nlk->ngroups; i++)
  			if (test_bit(i, nlk->groups))
  				nlk->netlink_unbind(sock_net(sk), i + 1);
  	}
  	if (sk->sk_protocol == NETLINK_GENERIC &&
  	    atomic_dec_return(&genl_sk_destructing_cnt) == 0)
  		wake_up(&genl_sk_destructing_waitq);

  	sock->sk = NULL;
  	wake_up_interruptible_all(&nlk->wait);
  
  	skb_queue_purge(&sk->sk_write_queue);

  	if (nlk->portid && nlk->bound) {

  		struct netlink_notify n = {

  						.net = sock_net(sk),

  						.protocol = sk->sk_protocol,

  						.portid = nlk->portid,

  					  };

  		blocking_notifier_call_chain(&netlink_chain,

  				NETLINK_URELEASE, &n);

  	}

  	module_put(nlk->module);

  	if (netlink_is_kernel(sk)) {

  		netlink_table_grab();

  		BUG_ON(nl_table[sk->sk_protocol].registered == 0);
  		if (--nl_table[sk->sk_protocol].registered == 0) {

  			struct listeners *old;
  
  			old = nl_deref_protected(nl_table[sk->sk_protocol].listeners);
  			RCU_INIT_POINTER(nl_table[sk->sk_protocol].listeners, NULL);
  			kfree_rcu(old, rcu);

  			nl_table[sk->sk_protocol].module = NULL;

  			nl_table[sk->sk_protocol].bind = NULL;

  			nl_table[sk->sk_protocol].unbind = NULL;

  			nl_table[sk->sk_protocol].flags = 0;

  			nl_table[sk->sk_protocol].registered = 0;
  		}

  		netlink_table_ungrab();

  	}

  	local_bh_disable();

  	sock_prot_inuse_add(sock_net(sk), &netlink_proto, -1);

  	local_bh_enable();

  	call_rcu(&nlk->rcu, deferred_put_nlk_sk);

  	return 0;
  }
  
  static int netlink_autobind(struct socket *sock)
  {
  	struct sock *sk = sock->sk;

  	struct net *net = sock_net(sk);

  	struct netlink_table *table = &nl_table[sk->sk_protocol];

  	s32 portid = task_tgid_vnr(current);

  	int err;

  	s32 rover = -4096;
  	bool ok;

  
  retry:
  	cond_resched();

  	rcu_read_lock();

  	ok = !__netlink_lookup(table, portid, net);
  	rcu_read_unlock();
  	if (!ok) {

  		/* Bind collision, search negative portid values. */

  		if (rover == -4096)
  			/* rover will be in range [S32_MIN, -4097] */
  			rover = S32_MIN + prandom_u32_max(-4096 - S32_MIN);
  		else if (rover >= -4096)

  			rover = -4097;

  		portid = rover--;

  		goto retry;

  	}

  	err = netlink_insert(sk, portid);

  	if (err == -EADDRINUSE)
  		goto retry;

  
  	/* If 2 threads race to autobind, that is fine.  */
  	if (err == -EBUSY)
  		err = 0;
  
  	return err;

  }

  /**
   * __netlink_ns_capable - General netlink message capability test
   * @nsp: NETLINK_CB of the socket buffer holding a netlink command from userspace.
   * @user_ns: The user namespace of the capability to use
   * @cap: The capability to use
   *
   * Test to see if the opener of the socket we received the message
   * from had when the netlink socket was created and the sender of the
   * message has has the capability @cap in the user namespace @user_ns.
   */
  bool __netlink_ns_capable(const struct netlink_skb_parms *nsp,
  			struct user_namespace *user_ns, int cap)
  {

  	return ((nsp->flags & NETLINK_SKB_DST) ||
  		file_ns_capable(nsp->sk->sk_socket->file, user_ns, cap)) &&
  		ns_capable(user_ns, cap);

  }
  EXPORT_SYMBOL(__netlink_ns_capable);
  
  /**
   * netlink_ns_capable - General netlink message capability test
   * @skb: socket buffer holding a netlink command from userspace
   * @user_ns: The user namespace of the capability to use
   * @cap: The capability to use
   *
   * Test to see if the opener of the socket we received the message
   * from had when the netlink socket was created and the sender of the
   * message has has the capability @cap in the user namespace @user_ns.
   */
  bool netlink_ns_capable(const struct sk_buff *skb,
  			struct user_namespace *user_ns, int cap)
  {
  	return __netlink_ns_capable(&NETLINK_CB(skb), user_ns, cap);
  }
  EXPORT_SYMBOL(netlink_ns_capable);
  
  /**
   * netlink_capable - Netlink global message capability test
   * @skb: socket buffer holding a netlink command from userspace
   * @cap: The capability to use
   *
   * Test to see if the opener of the socket we received the message
   * from had when the netlink socket was created and the sender of the
   * message has has the capability @cap in all user namespaces.
   */
  bool netlink_capable(const struct sk_buff *skb, int cap)
  {
  	return netlink_ns_capable(skb, &init_user_ns, cap);
  }
  EXPORT_SYMBOL(netlink_capable);
  
  /**
   * netlink_net_capable - Netlink network namespace message capability test
   * @skb: socket buffer holding a netlink command from userspace
   * @cap: The capability to use
   *
   * Test to see if the opener of the socket we received the message
   * from had when the netlink socket was created and the sender of the
   * message has has the capability @cap over the network namespace of
   * the socket we received the message from.
   */
  bool netlink_net_capable(const struct sk_buff *skb, int cap)
  {
  	return netlink_ns_capable(skb, sock_net(skb->sk)->user_ns, cap);
  }
  EXPORT_SYMBOL(netlink_net_capable);

  static inline int netlink_allowed(const struct socket *sock, unsigned int flag)

  {

  	return (nl_table[sock->sk->sk_protocol].flags & flag) ||

  		ns_capable(sock_net(sock->sk)->user_ns, CAP_NET_ADMIN);

  }

  static void
  netlink_update_subscriptions(struct sock *sk, unsigned int subscriptions)
  {
  	struct netlink_sock *nlk = nlk_sk(sk);
  
  	if (nlk->subscriptions && !subscriptions)
  		__sk_del_bind_node(sk);
  	else if (!nlk->subscriptions && subscriptions)
  		sk_add_bind_node(sk, &nl_table[sk->sk_protocol].mc_list);
  	nlk->subscriptions = subscriptions;
  }

  static int netlink_realloc_groups(struct sock *sk)

  {
  	struct netlink_sock *nlk = nlk_sk(sk);
  	unsigned int groups;

  	unsigned long *new_groups;

  	int err = 0;

  	netlink_table_grab();

  	groups = nl_table[sk->sk_protocol].groups;

  	if (!nl_table[sk->sk_protocol].registered) {

  		err = -ENOENT;

  		goto out_unlock;
  	}

  	if (nlk->ngroups >= groups)
  		goto out_unlock;

  	new_groups = krealloc(nlk->groups, NLGRPSZ(groups), GFP_ATOMIC);
  	if (new_groups == NULL) {
  		err = -ENOMEM;
  		goto out_unlock;
  	}

  	memset((char *)new_groups + NLGRPSZ(nlk->ngroups), 0,

  	       NLGRPSZ(groups) - NLGRPSZ(nlk->ngroups));
  
  	nlk->groups = new_groups;

  	nlk->ngroups = groups;

   out_unlock:
  	netlink_table_ungrab();
  	return err;

  }

  static void netlink_undo_bind(int group, long unsigned int groups,

  			      struct sock *sk)

  {

  	struct netlink_sock *nlk = nlk_sk(sk);

  	int undo;
  
  	if (!nlk->netlink_unbind)
  		return;
  
  	for (undo = 0; undo < group; undo++)

  		if (test_bit(undo, &groups))

  			nlk->netlink_unbind(sock_net(sk), undo + 1);

  }

  static int netlink_bind(struct socket *sock, struct sockaddr *addr,
  			int addr_len)

  {
  	struct sock *sk = sock->sk;

  	struct net *net = sock_net(sk);

  	struct netlink_sock *nlk = nlk_sk(sk);
  	struct sockaddr_nl *nladdr = (struct sockaddr_nl *)addr;

  	int err = 0;

  	long unsigned int groups = nladdr->nl_groups;

  	bool bound;

  	if (addr_len < sizeof(struct sockaddr_nl))
  		return -EINVAL;

  	if (nladdr->nl_family != AF_NETLINK)
  		return -EINVAL;
  
  	/* Only superuser is allowed to listen multicasts */

  	if (groups) {

  		if (!netlink_allowed(sock, NL_CFG_F_NONROOT_RECV))

  			return -EPERM;

  		err = netlink_realloc_groups(sk);
  		if (err)
  			return err;

  	}

  
  	if (nlk->ngroups == 0)
  		groups = 0;

  	else if (nlk->ngroups < 8*sizeof(groups))
  		groups &= (1UL << nlk->ngroups) - 1;

  	bound = nlk->bound;
  	if (bound) {
  		/* Ensure nlk->portid is up-to-date. */
  		smp_rmb();

  		if (nladdr->nl_pid != nlk->portid)

  			return -EINVAL;

  	}

  	netlink_lock_table();

  	if (nlk->netlink_bind && groups) {
  		int group;
  
  		for (group = 0; group < nlk->ngroups; group++) {
  			if (!test_bit(group, &groups))
  				continue;

  			err = nlk->netlink_bind(net, group + 1);

  			if (!err)
  				continue;

  			netlink_undo_bind(group, groups, sk);

  			goto unlock;

  		}
  	}

  	/* No need for barriers here as we return to user-space without
  	 * using any of the bound attributes.
  	 */
  	if (!bound) {

  		err = nladdr->nl_pid ?

  			netlink_insert(sk, nladdr->nl_pid) :

  			netlink_autobind(sock);

  		if (err) {

  			netlink_undo_bind(nlk->ngroups, groups, sk);

  			goto unlock;

  		}

  	}

  	if (!groups && (nlk->groups == NULL || !(u32)nlk->groups[0]))

  		goto unlock;
  	netlink_unlock_table();

  
  	netlink_table_grab();

  	netlink_update_subscriptions(sk, nlk->subscriptions +

  					 hweight32(groups) -

  					 hweight32(nlk->groups[0]));

  	nlk->groups[0] = (nlk->groups[0] & ~0xffffffffUL) | groups;

  	netlink_update_listeners(sk);

  	netlink_table_ungrab();
  
  	return 0;

  
  unlock:
  	netlink_unlock_table();
  	return err;

  }
  
  static int netlink_connect(struct socket *sock, struct sockaddr *addr,
  			   int alen, int flags)
  {
  	int err = 0;
  	struct sock *sk = sock->sk;
  	struct netlink_sock *nlk = nlk_sk(sk);

  	struct sockaddr_nl *nladdr = (struct sockaddr_nl *)addr;

  	if (alen < sizeof(addr->sa_family))
  		return -EINVAL;

  	if (addr->sa_family == AF_UNSPEC) {
  		sk->sk_state	= NETLINK_UNCONNECTED;

  		nlk->dst_portid	= 0;

  		nlk->dst_group  = 0;

  		return 0;
  	}
  	if (addr->sa_family != AF_NETLINK)
  		return -EINVAL;

  	if (alen < sizeof(struct sockaddr_nl))
  		return -EINVAL;

  	if ((nladdr->nl_groups || nladdr->nl_pid) &&

  	    !netlink_allowed(sock, NL_CFG_F_NONROOT_SEND))

  		return -EPERM;

  	/* No need for barriers here as we return to user-space without
  	 * using any of the bound attributes.
  	 */
  	if (!nlk->bound)

  		err = netlink_autobind(sock);
  
  	if (err == 0) {
  		sk->sk_state	= NETLINK_CONNECTED;

  		nlk->dst_portid = nladdr->nl_pid;

  		nlk->dst_group  = ffs(nladdr->nl_groups);

  	}
  
  	return err;
  }

  static int netlink_getname(struct socket *sock, struct sockaddr *addr,
  			   int *addr_len, int peer)

  {
  	struct sock *sk = sock->sk;
  	struct netlink_sock *nlk = nlk_sk(sk);

  	DECLARE_SOCKADDR(struct sockaddr_nl *, nladdr, addr);

  	nladdr->nl_family = AF_NETLINK;
  	nladdr->nl_pad = 0;
  	*addr_len = sizeof(*nladdr);
  
  	if (peer) {

  		nladdr->nl_pid = nlk->dst_portid;

  		nladdr->nl_groups = netlink_group_mask(nlk->dst_group);

  	} else {

  		nladdr->nl_pid = nlk->portid;

  		netlink_lock_table();

  		nladdr->nl_groups = nlk->groups ? nlk->groups[0] : 0;

  		netlink_unlock_table();

  	}
  	return 0;
  }

  static int netlink_ioctl(struct socket *sock, unsigned int cmd,
  			 unsigned long arg)
  {
  	/* try to hand this ioctl down to the NIC drivers.
  	 */
  	return -ENOIOCTLCMD;
  }

  static struct sock *netlink_getsockbyportid(struct sock *ssk, u32 portid)

  {

  	struct sock *sock;
  	struct netlink_sock *nlk;

  	sock = netlink_lookup(sock_net(ssk), ssk->sk_protocol, portid);

  	if (!sock)
  		return ERR_PTR(-ECONNREFUSED);
  
  	/* Don't bother queuing skb if kernel socket has no input function */
  	nlk = nlk_sk(sock);

  	if (sock->sk_state == NETLINK_CONNECTED &&

  	    nlk->dst_portid != nlk_sk(ssk)->portid) {

  		sock_put(sock);
  		return ERR_PTR(-ECONNREFUSED);
  	}
  	return sock;
  }
  
  struct sock *netlink_getsockbyfilp(struct file *filp)
  {

  	struct inode *inode = file_inode(filp);

  	struct sock *sock;
  
  	if (!S_ISSOCK(inode->i_mode))
  		return ERR_PTR(-ENOTSOCK);
  
  	sock = SOCKET_I(inode)->sk;
  	if (sock->sk_family != AF_NETLINK)
  		return ERR_PTR(-EINVAL);
  
  	sock_hold(sock);
  	return sock;
  }

  static struct sk_buff *netlink_alloc_large_skb(unsigned int size,
  					       int broadcast)

  {
  	struct sk_buff *skb;
  	void *data;

  	if (size <= NLMSG_GOODSIZE || broadcast)

  		return alloc_skb(size, GFP_KERNEL);

  	size = SKB_DATA_ALIGN(size) +
  	       SKB_DATA_ALIGN(sizeof(struct skb_shared_info));

  
  	data = vmalloc(size);
  	if (data == NULL)

  		return NULL;

  	skb = __build_skb(data, size);

  	if (skb == NULL)
  		vfree(data);

  	else

  		skb->destructor = netlink_skb_destructor;

  
  	return skb;

  }

  /*
   * Attach a skb to a netlink socket.
   * The caller must hold a reference to the destination socket. On error, the
   * reference is dropped. The skb is not send to the destination, just all
   * all error checks are performed and memory in the queue is reserved.
   * Return values:
   * < 0: error. skb freed, reference to sock dropped.
   * 0: continue
   * 1: repeat lookup - reference dropped while waiting for socket memory.
   */

  int netlink_attachskb(struct sock *sk, struct sk_buff *skb,

  		      long *timeo, struct sock *ssk)

  {
  	struct netlink_sock *nlk;
  
  	nlk = nlk_sk(sk);

  	if ((atomic_read(&sk->sk_rmem_alloc) > sk->sk_rcvbuf ||

  	     test_bit(NETLINK_S_CONGESTED, &nlk->state))) {

  		DECLARE_WAITQUEUE(wait, current);

  		if (!*timeo) {

  			if (!ssk || netlink_is_kernel(ssk))

  				netlink_overrun(sk);
  			sock_put(sk);
  			kfree_skb(skb);
  			return -EAGAIN;
  		}
  
  		__set_current_state(TASK_INTERRUPTIBLE);
  		add_wait_queue(&nlk->wait, &wait);
  
  		if ((atomic_read(&sk->sk_rmem_alloc) > sk->sk_rcvbuf ||

  		     test_bit(NETLINK_S_CONGESTED, &nlk->state)) &&

  		    !sock_flag(sk, SOCK_DEAD))

  			*timeo = schedule_timeout(*timeo);

  
  		__set_current_state(TASK_RUNNING);
  		remove_wait_queue(&nlk->wait, &wait);
  		sock_put(sk);
  
  		if (signal_pending(current)) {
  			kfree_skb(skb);

  			return sock_intr_errno(*timeo);

  		}
  		return 1;
  	}

  	netlink_skb_set_owner_r(skb, sk);

  	return 0;
  }

  static int __netlink_sendskb(struct sock *sk, struct sk_buff *skb)

  {

  	int len = skb->len;

  	netlink_deliver_tap(skb);

  	skb_queue_tail(&sk->sk_receive_queue, skb);

  	sk->sk_data_ready(sk);

  	return len;
  }
  
  int netlink_sendskb(struct sock *sk, struct sk_buff *skb)
  {
  	int len = __netlink_sendskb(sk, skb);

  	sock_put(sk);
  	return len;
  }
  
  void netlink_detachskb(struct sock *sk, struct sk_buff *skb)
  {
  	kfree_skb(skb);
  	sock_put(sk);
  }

  static struct sk_buff *netlink_trim(struct sk_buff *skb, gfp_t allocation)

  {
  	int delta;

  	WARN_ON(skb->sk != NULL);

  	delta = skb->end - skb->tail;

  	if (is_vmalloc_addr(skb->head) || delta * 2 < skb->truesize)

  		return skb;
  
  	if (skb_shared(skb)) {
  		struct sk_buff *nskb = skb_clone(skb, allocation);
  		if (!nskb)
  			return skb;

  		consume_skb(skb);

  		skb = nskb;
  	}

  	pskb_expand_head(skb, 0, -delta,
  			 (allocation & ~__GFP_DIRECT_RECLAIM) |
  			 __GFP_NOWARN | __GFP_NORETRY);

  	return skb;
  }

  static int netlink_unicast_kernel(struct sock *sk, struct sk_buff *skb,
  				  struct sock *ssk)

  {
  	int ret;
  	struct netlink_sock *nlk = nlk_sk(sk);
  
  	ret = -ECONNREFUSED;
  	if (nlk->netlink_rcv != NULL) {
  		ret = skb->len;

  		netlink_skb_set_owner_r(skb, sk);

  		NETLINK_CB(skb).sk = ssk;

  		netlink_deliver_tap_kernel(sk, ssk, skb);

  		nlk->netlink_rcv(skb);

  		consume_skb(skb);
  	} else {
  		kfree_skb(skb);

  	}

  	sock_put(sk);
  	return ret;
  }
  
  int netlink_unicast(struct sock *ssk, struct sk_buff *skb,

  		    u32 portid, int nonblock)

  {
  	struct sock *sk;
  	int err;
  	long timeo;
  
  	skb = netlink_trim(skb, gfp_any());
  
  	timeo = sock_sndtimeo(ssk, nonblock);
  retry:

  	sk = netlink_getsockbyportid(ssk, portid);

  	if (IS_ERR(sk)) {
  		kfree_skb(skb);
  		return PTR_ERR(sk);
  	}

  	if (netlink_is_kernel(sk))

  		return netlink_unicast_kernel(sk, skb, ssk);

  	if (sk_filter(sk, skb)) {

  		err = skb->len;

  		kfree_skb(skb);
  		sock_put(sk);
  		return err;
  	}

  	err = netlink_attachskb(sk, skb, &timeo, ssk);

  	if (err == 1)
  		goto retry;
  	if (err)
  		return err;

  	return netlink_sendskb(sk, skb);

  }

  EXPORT_SYMBOL(netlink_unicast);

  int netlink_has_listeners(struct sock *sk, unsigned int group)
  {
  	int res = 0;

  	struct listeners *listeners;

  	BUG_ON(!netlink_is_kernel(sk));

  
  	rcu_read_lock();
  	listeners = rcu_dereference(nl_table[sk->sk_protocol].listeners);

  	if (listeners && group - 1 < nl_table[sk->sk_protocol].groups)

  		res = test_bit(group - 1, listeners->masks);

  
  	rcu_read_unlock();

  	return res;
  }
  EXPORT_SYMBOL_GPL(netlink_has_listeners);

  static int netlink_broadcast_deliver(struct sock *sk, struct sk_buff *skb)

  {
  	struct netlink_sock *nlk = nlk_sk(sk);
  
  	if (atomic_read(&sk->sk_rmem_alloc) <= sk->sk_rcvbuf &&

  	    !test_bit(NETLINK_S_CONGESTED, &nlk->state)) {

  		netlink_skb_set_owner_r(skb, sk);

  		__netlink_sendskb(sk, skb);

  		return atomic_read(&sk->sk_rmem_alloc) > (sk->sk_rcvbuf >> 1);

  	}
  	return -1;
  }
  
  struct netlink_broadcast_data {
  	struct sock *exclude_sk;

  	struct net *net;

  	u32 portid;

  	u32 group;
  	int failure;

  	int delivery_failure;

  	int congested;
  	int delivered;

  	gfp_t allocation;

  	struct sk_buff *skb, *skb2;

  	int (*tx_filter)(struct sock *dsk, struct sk_buff *skb, void *data);
  	void *tx_data;

  };

  static void do_one_broadcast(struct sock *sk,
  				    struct netlink_broadcast_data *p)

  {
  	struct netlink_sock *nlk = nlk_sk(sk);
  	int val;
  
  	if (p->exclude_sk == sk)

  		return;

  	if (nlk->portid == p->portid || p->group - 1 >= nlk->ngroups ||

  	    !test_bit(p->group - 1, nlk->groups))

  		return;

  	if (!net_eq(sock_net(sk), p->net)) {
  		if (!(nlk->flags & NETLINK_F_LISTEN_ALL_NSID))
  			return;
  
  		if (!peernet_has_id(sock_net(sk), p->net))
  			return;
  
  		if (!file_ns_capable(sk->sk_socket->file, p->net->user_ns,
  				     CAP_NET_BROADCAST))
  			return;
  	}

  	if (p->failure) {
  		netlink_overrun(sk);

  		return;

  	}
  
  	sock_hold(sk);
  	if (p->skb2 == NULL) {

  		if (skb_shared(p->skb)) {

  			p->skb2 = skb_clone(p->skb, p->allocation);
  		} else {

  			p->skb2 = skb_get(p->skb);
  			/*
  			 * skb ownership may have been set when
  			 * delivered to a previous socket.
  			 */
  			skb_orphan(p->skb2);

  		}
  	}
  	if (p->skb2 == NULL) {
  		netlink_overrun(sk);
  		/* Clone failed. Notify ALL listeners. */
  		p->failure = 1;

  		if (nlk->flags & NETLINK_F_BROADCAST_SEND_ERROR)

  			p->delivery_failure = 1;

  		goto out;
  	}
  	if (p->tx_filter && p->tx_filter(sk, p->skb2, p->tx_data)) {

  		kfree_skb(p->skb2);
  		p->skb2 = NULL;

  		goto out;
  	}
  	if (sk_filter(sk, p->skb2)) {

  		kfree_skb(p->skb2);
  		p->skb2 = NULL;

  		goto out;
  	}
  	NETLINK_CB(p->skb2).nsid = peernet2id(sock_net(sk), p->net);

  	if (NETLINK_CB(p->skb2).nsid != NETNSA_NSID_NOT_ASSIGNED)
  		NETLINK_CB(p->skb2).nsid_is_set = true;

  	val = netlink_broadcast_deliver(sk, p->skb2);
  	if (val < 0) {

  		netlink_overrun(sk);

  		if (nlk->flags & NETLINK_F_BROADCAST_SEND_ERROR)

  			p->delivery_failure = 1;

  	} else {
  		p->congested |= val;
  		p->delivered = 1;
  		p->skb2 = NULL;
  	}

  out:

  	sock_put(sk);

  }

  int netlink_broadcast_filtered(struct sock *ssk, struct sk_buff *skb, u32 portid,

  	u32 group, gfp_t allocation,
  	int (*filter)(struct sock *dsk, struct sk_buff *skb, void *data),
  	void *filter_data)

  {

  	struct net *net = sock_net(ssk);

  	struct netlink_broadcast_data info;

  	struct sock *sk;
  
  	skb = netlink_trim(skb, allocation);
  
  	info.exclude_sk = ssk;

  	info.net = net;

  	info.portid = portid;

  	info.group = group;
  	info.failure = 0;

  	info.delivery_failure = 0;

  	info.congested = 0;
  	info.delivered = 0;
  	info.allocation = allocation;
  	info.skb = skb;
  	info.skb2 = NULL;

  	info.tx_filter = filter;
  	info.tx_data = filter_data;

  
  	/* While we sleep in clone, do not allow to change socket list */
  
  	netlink_lock_table();

  	sk_for_each_bound(sk, &nl_table[ssk->sk_protocol].mc_list)

  		do_one_broadcast(sk, &info);

  	consume_skb(skb);

  	netlink_unlock_table();

  	if (info.delivery_failure) {
  		kfree_skb(info.skb2);

  		return -ENOBUFS;

  	}
  	consume_skb(info.skb2);

  	if (info.delivered) {

  		if (info.congested && gfpflags_allow_blocking(allocation))

  			yield();
  		return 0;
  	}

  	return -ESRCH;
  }

  EXPORT_SYMBOL(netlink_broadcast_filtered);

  int netlink_broadcast(struct sock *ssk, struct sk_buff *skb, u32 portid,

  		      u32 group, gfp_t allocation)
  {

  	return netlink_broadcast_filtered(ssk, skb, portid, group, allocation,

  		NULL, NULL);
  }

  EXPORT_SYMBOL(netlink_broadcast);

  
  struct netlink_set_err_data {
  	struct sock *exclude_sk;

  	u32 portid;

  	u32 group;
  	int code;
  };

  static int do_one_set_err(struct sock *sk, struct netlink_set_err_data *p)

  {
  	struct netlink_sock *nlk = nlk_sk(sk);

  	int ret = 0;

  
  	if (sk == p->exclude_sk)
  		goto out;

  	if (!net_eq(sock_net(sk), sock_net(p->exclude_sk)))

  		goto out;

  	if (nlk->portid == p->portid || p->group - 1 >= nlk->ngroups ||

  	    !test_bit(p->group - 1, nlk->groups))

  		goto out;

  	if (p->code == ENOBUFS && nlk->flags & NETLINK_F_RECV_NO_ENOBUFS) {

  		ret = 1;
  		goto out;
  	}

  	sk->sk_err = p->code;
  	sk->sk_error_report(sk);
  out:

  	return ret;

  }

  /**
   * netlink_set_err - report error to broadcast listeners
   * @ssk: the kernel netlink socket, as returned by netlink_kernel_create()

   * @portid: the PORTID of a process that we want to skip (if any)

   * @group: the broadcast group that will notice the error

   * @code: error code, must be negative (as usual in kernelspace)

   *
   * This function returns the number of broadcast listeners that have set the

   * NETLINK_NO_ENOBUFS socket option.

   */

  int netlink_set_err(struct sock *ssk, u32 portid, u32 group, int code)

  {
  	struct netlink_set_err_data info;