net/netfilter/nfnetlink_acct.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0-or-later
 /*
  * (C) 2011 Pablo Neira Ayuso <pablo@netfilter.org>
  * (C) 2011 Intra2net AG <https://www.intra2net.com>
  */
 #include <linux/init.h>
 #include <linux/module.h>
 #include <linux/kernel.h>
 #include <linux/skbuff.h>
 #include <linux/atomic.h>
 #include <linux/refcount.h>
 #include <linux/netlink.h>
 #include <linux/rculist.h>
 #include <linux/slab.h>
 #include <linux/types.h>
 #include <linux/errno.h>
 #include <net/netlink.h>
 #include <net/sock.h>
 #include <net/netns/generic.h>

 #include <linux/netfilter.h>
 #include <linux/netfilter/nfnetlink.h>
 #include <linux/netfilter/nfnetlink_acct.h>

 MODULE_LICENSE("GPL");
 MODULE_AUTHOR("Pablo Neira Ayuso <pablo@netfilter.org>");
 MODULE_DESCRIPTION("nfacct: Extended Netfilter accounting infrastructure");

 struct nf_acct {
 	atomic64_t		pkts;
 	atomic64_t		bytes;
 	unsigned long		flags;
 	struct list_head	head;
 	refcount_t		refcnt;
 	char			name[NFACCT_NAME_MAX];
 	struct rcu_head		rcu_head;
 	char			data[];
 };

 struct nfacct_filter {
 	u32 value;
 	u32 mask;
 };

 struct nfnl_acct_net {
 	struct list_head        nfnl_acct_list;
 };

 static unsigned int nfnl_acct_net_id __read_mostly;

 static inline struct nfnl_acct_net *nfnl_acct_pernet(struct net *net)
 {
 	return net_generic(net, nfnl_acct_net_id);
 }

 #define NFACCT_F_QUOTA (NFACCT_F_QUOTA_PKTS | NFACCT_F_QUOTA_BYTES)
 #define NFACCT_OVERQUOTA_BIT	2	/* NFACCT_F_OVERQUOTA */

 static int nfnl_acct_new(struct sk_buff *skb, const struct nfnl_info *info,
 			 const struct nlattr * const tb[])
 {
 	struct nfnl_acct_net *nfnl_acct_net = nfnl_acct_pernet(info->net);
 	struct nf_acct *nfacct, *matching = NULL;
 	unsigned int size = 0;
 	char *acct_name;
 	u32 flags = 0;

 	if (!tb[NFACCT_NAME])
 		return -EINVAL;

 	acct_name = nla_data(tb[NFACCT_NAME]);
 	if (strlen(acct_name) == 0)
 		return -EINVAL;

 	list_for_each_entry(nfacct, &nfnl_acct_net->nfnl_acct_list, head) {
 		if (strncmp(nfacct->name, acct_name, NFACCT_NAME_MAX) != 0)
 			continue;

                 if (info->nlh->nlmsg_flags & NLM_F_EXCL)
 			return -EEXIST;

 		matching = nfacct;
 		break;
         }

 	if (matching) {
 		if (info->nlh->nlmsg_flags & NLM_F_REPLACE) {
 			/* reset counters if you request a replacement. */
 			atomic64_set(&matching->pkts, 0);
 			atomic64_set(&matching->bytes, 0);
 			smp_mb__before_atomic();
 			/* reset overquota flag if quota is enabled. */
 			if ((matching->flags & NFACCT_F_QUOTA))
 				clear_bit(NFACCT_OVERQUOTA_BIT,
 					  &matching->flags);
 			return 0;
 		}
 		return -EBUSY;
 	}

 	if (tb[NFACCT_FLAGS]) {
 		flags = ntohl(nla_get_be32(tb[NFACCT_FLAGS]));
 		if (flags & ~NFACCT_F_QUOTA)
 			return -EOPNOTSUPP;
 		if ((flags & NFACCT_F_QUOTA) == NFACCT_F_QUOTA)
 			return -EINVAL;
 		if (flags & NFACCT_F_OVERQUOTA)
 			return -EINVAL;
 		if ((flags & NFACCT_F_QUOTA) && !tb[NFACCT_QUOTA])
 			return -EINVAL;

 		size += sizeof(u64);
 	}

 	nfacct = kzalloc(sizeof(struct nf_acct) + size, GFP_KERNEL);
 	if (nfacct == NULL)
 		return -ENOMEM;

 	if (flags & NFACCT_F_QUOTA) {
 		u64 *quota = (u64 *)nfacct->data;

 		*quota = be64_to_cpu(nla_get_be64(tb[NFACCT_QUOTA]));
 		nfacct->flags = flags;
 	}

 	nla_strscpy(nfacct->name, tb[NFACCT_NAME], NFACCT_NAME_MAX);

 	if (tb[NFACCT_BYTES]) {
 		atomic64_set(&nfacct->bytes,
 			     be64_to_cpu(nla_get_be64(tb[NFACCT_BYTES])));
 	}
 	if (tb[NFACCT_PKTS]) {
 		atomic64_set(&nfacct->pkts,
 			     be64_to_cpu(nla_get_be64(tb[NFACCT_PKTS])));
 	}
 	refcount_set(&nfacct->refcnt, 1);
 	list_add_tail_rcu(&nfacct->head, &nfnl_acct_net->nfnl_acct_list);
 	return 0;
 }

 static int
 nfnl_acct_fill_info(struct sk_buff *skb, u32 portid, u32 seq, u32 type,
 		   int event, struct nf_acct *acct)
 {
 	struct nlmsghdr *nlh;
 	unsigned int flags = portid ? NLM_F_MULTI : 0;
 	u64 pkts, bytes;
 	u32 old_flags;

 	event = nfnl_msg_type(NFNL_SUBSYS_ACCT, event);
 	nlh = nfnl_msg_put(skb, portid, seq, event, flags, AF_UNSPEC,
 			   NFNETLINK_V0, 0);
 	if (!nlh)
 		goto nlmsg_failure;

 	if (nla_put_string(skb, NFACCT_NAME, acct->name))
 		goto nla_put_failure;

 	old_flags = acct->flags;
 	if (type == NFNL_MSG_ACCT_GET_CTRZERO) {
 		pkts = atomic64_xchg(&acct->pkts, 0);
 		bytes = atomic64_xchg(&acct->bytes, 0);
 		smp_mb__before_atomic();
 		if (acct->flags & NFACCT_F_QUOTA)
 			clear_bit(NFACCT_OVERQUOTA_BIT, &acct->flags);
 	} else {
 		pkts = atomic64_read(&acct->pkts);
 		bytes = atomic64_read(&acct->bytes);
 	}
 	if (nla_put_be64(skb, NFACCT_PKTS, cpu_to_be64(pkts),
 			 NFACCT_PAD) ||
 	    nla_put_be64(skb, NFACCT_BYTES, cpu_to_be64(bytes),
 			 NFACCT_PAD) ||
 	    nla_put_be32(skb, NFACCT_USE, htonl(refcount_read(&acct->refcnt))))
 		goto nla_put_failure;
 	if (acct->flags & NFACCT_F_QUOTA) {
 		u64 *quota = (u64 *)acct->data;

 		if (nla_put_be32(skb, NFACCT_FLAGS, htonl(old_flags)) ||
 		    nla_put_be64(skb, NFACCT_QUOTA, cpu_to_be64(*quota),
 				 NFACCT_PAD))
 			goto nla_put_failure;
 	}
 	nlmsg_end(skb, nlh);
 	return skb->len;

 nlmsg_failure:
 nla_put_failure:
 	nlmsg_cancel(skb, nlh);
 	return -1;
 }

 static int
 nfnl_acct_dump(struct sk_buff *skb, struct netlink_callback *cb)
 {
 	struct net *net = sock_net(skb->sk);
 	struct nfnl_acct_net *nfnl_acct_net = nfnl_acct_pernet(net);
 	struct nf_acct *cur, *last;
 	const struct nfacct_filter *filter = cb->data;

 	if (cb->args[2])
 		return 0;

 	last = (struct nf_acct *)cb->args[1];
 	if (cb->args[1])
 		cb->args[1] = 0;

 	rcu_read_lock();
 	list_for_each_entry_rcu(cur, &nfnl_acct_net->nfnl_acct_list, head) {
 		if (last) {
 			if (cur != last)
 				continue;

 			last = NULL;
 		}

 		if (filter && (cur->flags & filter->mask) != filter->value)
 			continue;

 		if (nfnl_acct_fill_info(skb, NETLINK_CB(cb->skb).portid,
 				       cb->nlh->nlmsg_seq,
 				       NFNL_MSG_TYPE(cb->nlh->nlmsg_type),
 				       NFNL_MSG_ACCT_NEW, cur) < 0) {
 			cb->args[1] = (unsigned long)cur;
 			break;
 		}
 	}
 	if (!cb->args[1])
 		cb->args[2] = 1;
 	rcu_read_unlock();
 	return skb->len;
 }

 static int nfnl_acct_done(struct netlink_callback *cb)
 {
 	kfree(cb->data);
 	return 0;
 }

 static const struct nla_policy filter_policy[NFACCT_FILTER_MAX + 1] = {
 	[NFACCT_FILTER_MASK]	= { .type = NLA_U32 },
 	[NFACCT_FILTER_VALUE]	= { .type = NLA_U32 },
 };

 static int nfnl_acct_start(struct netlink_callback *cb)
 {
 	const struct nlattr *const attr = cb->data;
 	struct nlattr *tb[NFACCT_FILTER_MAX + 1];
 	struct nfacct_filter *filter;
 	int err;

 	if (!attr)
 		return 0;

 	err = nla_parse_nested_deprecated(tb, NFACCT_FILTER_MAX, attr,
 					  filter_policy, NULL);
 	if (err < 0)
 		return err;

 	if (!tb[NFACCT_FILTER_MASK] || !tb[NFACCT_FILTER_VALUE])
 		return -EINVAL;

 	filter = kzalloc(sizeof(struct nfacct_filter), GFP_KERNEL);
 	if (!filter)
 		return -ENOMEM;

 	filter->mask = ntohl(nla_get_be32(tb[NFACCT_FILTER_MASK]));
 	filter->value = ntohl(nla_get_be32(tb[NFACCT_FILTER_VALUE]));
 	cb->data = filter;

 	return 0;
 }

 static int nfnl_acct_get(struct sk_buff *skb, const struct nfnl_info *info,
 			 const struct nlattr * const tb[])
 {
 	struct nfnl_acct_net *nfnl_acct_net = nfnl_acct_pernet(info->net);
 	int ret = -ENOENT;
 	struct nf_acct *cur;
 	char *acct_name;

 	if (info->nlh->nlmsg_flags & NLM_F_DUMP) {
 		struct netlink_dump_control c = {
 			.dump = nfnl_acct_dump,
 			.start = nfnl_acct_start,
 			.done = nfnl_acct_done,
 			.data = (void *)tb[NFACCT_FILTER],
 		};

 		return netlink_dump_start(info->sk, skb, info->nlh, &c);
 	}

 	if (!tb[NFACCT_NAME])
 		return -EINVAL;
 	acct_name = nla_data(tb[NFACCT_NAME]);

 	list_for_each_entry(cur, &nfnl_acct_net->nfnl_acct_list, head) {
 		struct sk_buff *skb2;

 		if (strncmp(cur->name, acct_name, NFACCT_NAME_MAX)!= 0)
 			continue;

 		skb2 = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
 		if (skb2 == NULL) {
 			ret = -ENOMEM;
 			break;
 		}

 		ret = nfnl_acct_fill_info(skb2, NETLINK_CB(skb).portid,
 					  info->nlh->nlmsg_seq,
 					  NFNL_MSG_TYPE(info->nlh->nlmsg_type),
 					  NFNL_MSG_ACCT_NEW, cur);
 		if (ret <= 0) {
 			kfree_skb(skb2);
 			break;
 		}
 		ret = netlink_unicast(info->sk, skb2, NETLINK_CB(skb).portid,
 				      MSG_DONTWAIT);
 		if (ret > 0)
 			ret = 0;

 		/* this avoids a loop in nfnetlink. */
 		return ret == -EAGAIN ? -ENOBUFS : ret;
 	}
 	return ret;
 }

 /* try to delete object, fail if it is still in use. */
 static int nfnl_acct_try_del(struct nf_acct *cur)
 {
 	int ret = 0;

 	/* We want to avoid races with nfnl_acct_put. So only when the current
 	 * refcnt is 1, we decrease it to 0.
 	 */
 	if (refcount_dec_if_one(&cur->refcnt)) {
 		/* We are protected by nfnl mutex. */
 		list_del_rcu(&cur->head);
 		kfree_rcu(cur, rcu_head);
 	} else {
 		ret = -EBUSY;
 	}
 	return ret;
 }

 static int nfnl_acct_del(struct sk_buff *skb, const struct nfnl_info *info,
 			 const struct nlattr * const tb[])
 {
 	struct nfnl_acct_net *nfnl_acct_net = nfnl_acct_pernet(info->net);
 	struct nf_acct *cur, *tmp;
 	int ret = -ENOENT;
 	char *acct_name;

 	if (!tb[NFACCT_NAME]) {
 		list_for_each_entry_safe(cur, tmp, &nfnl_acct_net->nfnl_acct_list, head)
 			nfnl_acct_try_del(cur);

 		return 0;
 	}
 	acct_name = nla_data(tb[NFACCT_NAME]);

 	list_for_each_entry(cur, &nfnl_acct_net->nfnl_acct_list, head) {
 		if (strncmp(cur->name, acct_name, NFACCT_NAME_MAX) != 0)
 			continue;

 		ret = nfnl_acct_try_del(cur);
 		if (ret < 0)
 			return ret;

 		break;
 	}
 	return ret;
 }

 static const struct nla_policy nfnl_acct_policy[NFACCT_MAX+1] = {
 	[NFACCT_NAME] = { .type = NLA_NUL_STRING, .len = NFACCT_NAME_MAX-1 },
 	[NFACCT_BYTES] = { .type = NLA_U64 },
 	[NFACCT_PKTS] = { .type = NLA_U64 },
 	[NFACCT_FLAGS] = { .type = NLA_U32 },
 	[NFACCT_QUOTA] = { .type = NLA_U64 },
 	[NFACCT_FILTER] = {.type = NLA_NESTED },
 };

 static const struct nfnl_callback nfnl_acct_cb[NFNL_MSG_ACCT_MAX] = {
 	[NFNL_MSG_ACCT_NEW] = {
 		.call		= nfnl_acct_new,
 		.type		= NFNL_CB_MUTEX,
 		.attr_count	= NFACCT_MAX,
 		.policy		= nfnl_acct_policy
 	},
 	[NFNL_MSG_ACCT_GET] = {
 		.call		= nfnl_acct_get,
 		.type		= NFNL_CB_MUTEX,
 		.attr_count	= NFACCT_MAX,
 		.policy		= nfnl_acct_policy
 	},
 	[NFNL_MSG_ACCT_GET_CTRZERO] = {
 		.call		= nfnl_acct_get,
 		.type		= NFNL_CB_MUTEX,
 		.attr_count	= NFACCT_MAX,
 		.policy		= nfnl_acct_policy
 	},
 	[NFNL_MSG_ACCT_DEL] = {
 		.call		= nfnl_acct_del,
 		.type		= NFNL_CB_MUTEX,
 		.attr_count	= NFACCT_MAX,
 		.policy		= nfnl_acct_policy
 	},
 };

 static const struct nfnetlink_subsystem nfnl_acct_subsys = {
 	.name				= "acct",
 	.subsys_id			= NFNL_SUBSYS_ACCT,
 	.cb_count			= NFNL_MSG_ACCT_MAX,
 	.cb				= nfnl_acct_cb,
 };

 MODULE_ALIAS_NFNL_SUBSYS(NFNL_SUBSYS_ACCT);

 struct nf_acct *nfnl_acct_find_get(struct net *net, const char *acct_name)
 {
 	struct nfnl_acct_net *nfnl_acct_net = nfnl_acct_pernet(net);
 	struct nf_acct *cur, *acct = NULL;

 	rcu_read_lock();
 	list_for_each_entry_rcu(cur, &nfnl_acct_net->nfnl_acct_list, head) {
 		if (strncmp(cur->name, acct_name, NFACCT_NAME_MAX)!= 0)
 			continue;

 		if (!try_module_get(THIS_MODULE))
 			goto err;

 		if (!refcount_inc_not_zero(&cur->refcnt)) {
 			module_put(THIS_MODULE);
 			goto err;
 		}

 		acct = cur;
 		break;
 	}
 err:
 	rcu_read_unlock();
 	return acct;
 }
 EXPORT_SYMBOL_GPL(nfnl_acct_find_get);

 void nfnl_acct_put(struct nf_acct *acct)
 {
 	if (refcount_dec_and_test(&acct->refcnt))
 		kfree_rcu(acct, rcu_head);

 	module_put(THIS_MODULE);
 }
 EXPORT_SYMBOL_GPL(nfnl_acct_put);

 void nfnl_acct_update(const struct sk_buff *skb, struct nf_acct *nfacct)
 {
 	atomic64_inc(&nfacct->pkts);
 	atomic64_add(skb->len, &nfacct->bytes);
 }
 EXPORT_SYMBOL_GPL(nfnl_acct_update);

 static void nfnl_overquota_report(struct net *net, struct nf_acct *nfacct)
 {
 	int ret;
 	struct sk_buff *skb;

 	skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_ATOMIC);
 	if (skb == NULL)
 		return;

 	ret = nfnl_acct_fill_info(skb, 0, 0, NFNL_MSG_ACCT_OVERQUOTA, 0,
 				  nfacct);
 	if (ret <= 0) {
 		kfree_skb(skb);
 		return;
 	}
 	nfnetlink_broadcast(net, skb, 0, NFNLGRP_ACCT_QUOTA, GFP_ATOMIC);
 }

 int nfnl_acct_overquota(struct net *net, struct nf_acct *nfacct)
 {
 	u64 now;
 	u64 *quota;
 	int ret = NFACCT_UNDERQUOTA;

 	/* no place here if we don't have a quota */
 	if (!(nfacct->flags & NFACCT_F_QUOTA))
 		return NFACCT_NO_QUOTA;

 	quota = (u64 *)nfacct->data;
 	now = (nfacct->flags & NFACCT_F_QUOTA_PKTS) ?
 	       atomic64_read(&nfacct->pkts) : atomic64_read(&nfacct->bytes);

 	ret = now > *quota;

 	if (now >= *quota &&
 	    !test_and_set_bit(NFACCT_OVERQUOTA_BIT, &nfacct->flags)) {
 		nfnl_overquota_report(net, nfacct);
 	}

 	return ret;
 }
 EXPORT_SYMBOL_GPL(nfnl_acct_overquota);

 static int __net_init nfnl_acct_net_init(struct net *net)
 {
 	INIT_LIST_HEAD(&nfnl_acct_pernet(net)->nfnl_acct_list);

 	return 0;
 }

 static void __net_exit nfnl_acct_net_exit(struct net *net)
 {
 	struct nfnl_acct_net *nfnl_acct_net = nfnl_acct_pernet(net);
 	struct nf_acct *cur, *tmp;

 	list_for_each_entry_safe(cur, tmp, &nfnl_acct_net->nfnl_acct_list, head) {
 		list_del_rcu(&cur->head);

 		if (refcount_dec_and_test(&cur->refcnt))
 			kfree_rcu(cur, rcu_head);
 	}
 }

 static struct pernet_operations nfnl_acct_ops = {
         .init   = nfnl_acct_net_init,
         .exit   = nfnl_acct_net_exit,
         .id     = &nfnl_acct_net_id,
         .size   = sizeof(struct nfnl_acct_net),
 };

 static int __init nfnl_acct_init(void)
 {
 	int ret;

 	ret = register_pernet_subsys(&nfnl_acct_ops);
 	if (ret < 0) {
 		pr_err("nfnl_acct_init: failed to register pernet ops\n");
 		goto err_out;
 	}

 	ret = nfnetlink_subsys_register(&nfnl_acct_subsys);
 	if (ret < 0) {
 		pr_err("nfnl_acct_init: cannot register with nfnetlink.\n");
 		goto cleanup_pernet;
 	}
 	return 0;

 cleanup_pernet:
 	unregister_pernet_subsys(&nfnl_acct_ops);
 err_out:
 	return ret;
 }

 static void __exit nfnl_acct_exit(void)
 {
 	nfnetlink_subsys_unregister(&nfnl_acct_subsys);
 	unregister_pernet_subsys(&nfnl_acct_ops);
 }

 module_init(nfnl_acct_init);
 module_exit(nfnl_acct_exit);
	// SPDX-License-Identifier: GPL-2.0-or-later
	/*
	* (C) 2011 Pablo Neira Ayuso <pablo@netfilter.org>
	* (C) 2011 Intra2net AG <https://www.intra2net.com>
	*/
	#include <linux/init.h>
	#include <linux/module.h>
	#include <linux/kernel.h>
	#include <linux/skbuff.h>
	#include <linux/atomic.h>
	#include <linux/refcount.h>
	#include <linux/netlink.h>
	#include <linux/rculist.h>
	#include <linux/slab.h>
	#include <linux/types.h>
	#include <linux/errno.h>
	#include <net/netlink.h>
	#include <net/sock.h>
	#include <net/netns/generic.h>

	#include <linux/netfilter.h>
	#include <linux/netfilter/nfnetlink.h>
	#include <linux/netfilter/nfnetlink_acct.h>

	MODULE_LICENSE("GPL");
	MODULE_AUTHOR("Pablo Neira Ayuso <pablo@netfilter.org>");
	MODULE_DESCRIPTION("nfacct: Extended Netfilter accounting infrastructure");

	struct nf_acct {
	atomic64_t pkts;
	atomic64_t bytes;
	unsigned long flags;
	struct list_head head;
	refcount_t refcnt;
	char name[NFACCT_NAME_MAX];
	struct rcu_head rcu_head;
	char data[];
	};

	struct nfacct_filter {
	u32 value;
	u32 mask;
	};

	struct nfnl_acct_net {
	struct list_head nfnl_acct_list;
	};

	static unsigned int nfnl_acct_net_id __read_mostly;

	static inline struct nfnl_acct_net nfnl_acct_pernet(struct net net)
	{
	return net_generic(net, nfnl_acct_net_id);
	}

	#define NFACCT_F_QUOTA (NFACCT_F_QUOTA_PKTS \| NFACCT_F_QUOTA_BYTES)
	#define NFACCT_OVERQUOTA_BIT 2 /* NFACCT_F_OVERQUOTA */

	static int nfnl_acct_new(struct sk_buff skb, const struct nfnl_info info,
	const struct nlattr * const tb[])
	{
	struct nfnl_acct_net *nfnl_acct_net = nfnl_acct_pernet(info->net);
	struct nf_acct nfacct, matching = NULL;
	unsigned int size = 0;
	char *acct_name;
	u32 flags = 0;

	if (!tb[NFACCT_NAME])
	return -EINVAL;

	acct_name = nla_data(tb[NFACCT_NAME]);
	if (strlen(acct_name) == 0)
	return -EINVAL;

	list_for_each_entry(nfacct, &nfnl_acct_net->nfnl_acct_list, head) {
	if (strncmp(nfacct->name, acct_name, NFACCT_NAME_MAX) != 0)
	continue;

	if (info->nlh->nlmsg_flags & NLM_F_EXCL)
	return -EEXIST;

	matching = nfacct;
	break;
	}

	if (matching) {
	if (info->nlh->nlmsg_flags & NLM_F_REPLACE) {
	/* reset counters if you request a replacement. */
	atomic64_set(&matching->pkts, 0);
	atomic64_set(&matching->bytes, 0);
	smp_mb__before_atomic();
	/* reset overquota flag if quota is enabled. */
	if ((matching->flags & NFACCT_F_QUOTA))
	clear_bit(NFACCT_OVERQUOTA_BIT,
	&matching->flags);
	return 0;
	}
	return -EBUSY;
	}

	if (tb[NFACCT_FLAGS]) {
	flags = ntohl(nla_get_be32(tb[NFACCT_FLAGS]));
	if (flags & ~NFACCT_F_QUOTA)
	return -EOPNOTSUPP;
	if ((flags & NFACCT_F_QUOTA) == NFACCT_F_QUOTA)
	return -EINVAL;
	if (flags & NFACCT_F_OVERQUOTA)
	return -EINVAL;
	if ((flags & NFACCT_F_QUOTA) && !tb[NFACCT_QUOTA])
	return -EINVAL;

	size += sizeof(u64);
	}

	nfacct = kzalloc(sizeof(struct nf_acct) + size, GFP_KERNEL);
	if (nfacct == NULL)
	return -ENOMEM;

	if (flags & NFACCT_F_QUOTA) {
	u64 quota = (u64 )nfacct->data;

	*quota = be64_to_cpu(nla_get_be64(tb[NFACCT_QUOTA]));
	nfacct->flags = flags;
	}

	nla_strscpy(nfacct->name, tb[NFACCT_NAME], NFACCT_NAME_MAX);

	if (tb[NFACCT_BYTES]) {
	atomic64_set(&nfacct->bytes,
	be64_to_cpu(nla_get_be64(tb[NFACCT_BYTES])));
	}
	if (tb[NFACCT_PKTS]) {
	atomic64_set(&nfacct->pkts,
	be64_to_cpu(nla_get_be64(tb[NFACCT_PKTS])));
	}
	refcount_set(&nfacct->refcnt, 1);
	list_add_tail_rcu(&nfacct->head, &nfnl_acct_net->nfnl_acct_list);
	return 0;
	}

	static int
	nfnl_acct_fill_info(struct sk_buff *skb, u32 portid, u32 seq, u32 type,
	int event, struct nf_acct *acct)
	{
	struct nlmsghdr *nlh;
	unsigned int flags = portid ? NLM_F_MULTI : 0;
	u64 pkts, bytes;
	u32 old_flags;

	event = nfnl_msg_type(NFNL_SUBSYS_ACCT, event);
	nlh = nfnl_msg_put(skb, portid, seq, event, flags, AF_UNSPEC,
	NFNETLINK_V0, 0);
	if (!nlh)
	goto nlmsg_failure;

	if (nla_put_string(skb, NFACCT_NAME, acct->name))
	goto nla_put_failure;

	old_flags = acct->flags;
	if (type == NFNL_MSG_ACCT_GET_CTRZERO) {
	pkts = atomic64_xchg(&acct->pkts, 0);
	bytes = atomic64_xchg(&acct->bytes, 0);
	smp_mb__before_atomic();
	if (acct->flags & NFACCT_F_QUOTA)
	clear_bit(NFACCT_OVERQUOTA_BIT, &acct->flags);
	} else {
	pkts = atomic64_read(&acct->pkts);
	bytes = atomic64_read(&acct->bytes);
	}
	if (nla_put_be64(skb, NFACCT_PKTS, cpu_to_be64(pkts),
	NFACCT_PAD) \|\|
	nla_put_be64(skb, NFACCT_BYTES, cpu_to_be64(bytes),
	NFACCT_PAD) \|\|
	nla_put_be32(skb, NFACCT_USE, htonl(refcount_read(&acct->refcnt))))
	goto nla_put_failure;
	if (acct->flags & NFACCT_F_QUOTA) {
	u64 quota = (u64 )acct->data;

	if (nla_put_be32(skb, NFACCT_FLAGS, htonl(old_flags)) \|\|
	nla_put_be64(skb, NFACCT_QUOTA, cpu_to_be64(*quota),
	NFACCT_PAD))
	goto nla_put_failure;
	}
	nlmsg_end(skb, nlh);
	return skb->len;

	nlmsg_failure:
	nla_put_failure:
	nlmsg_cancel(skb, nlh);
	return -1;
	}

	static int
	nfnl_acct_dump(struct sk_buff skb, struct netlink_callback cb)
	{
	struct net *net = sock_net(skb->sk);
	struct nfnl_acct_net *nfnl_acct_net = nfnl_acct_pernet(net);
	struct nf_acct cur, last;
	const struct nfacct_filter *filter = cb->data;

	if (cb->args[2])
	return 0;

	last = (struct nf_acct *)cb->args[1];
	if (cb->args[1])
	cb->args[1] = 0;

	rcu_read_lock();
	list_for_each_entry_rcu(cur, &nfnl_acct_net->nfnl_acct_list, head) {
	if (last) {
	if (cur != last)
	continue;

	last = NULL;
	}

	if (filter && (cur->flags & filter->mask) != filter->value)
	continue;

	if (nfnl_acct_fill_info(skb, NETLINK_CB(cb->skb).portid,
	cb->nlh->nlmsg_seq,
	NFNL_MSG_TYPE(cb->nlh->nlmsg_type),
	NFNL_MSG_ACCT_NEW, cur) < 0) {
	cb->args[1] = (unsigned long)cur;
	break;
	}
	}
	if (!cb->args[1])
	cb->args[2] = 1;
	rcu_read_unlock();
	return skb->len;
	}

	static int nfnl_acct_done(struct netlink_callback *cb)
	{
	kfree(cb->data);
	return 0;
	}

	static const struct nla_policy filter_policy[NFACCT_FILTER_MAX + 1] = {
	[NFACCT_FILTER_MASK] = { .type = NLA_U32 },
	[NFACCT_FILTER_VALUE] = { .type = NLA_U32 },
	};

	static int nfnl_acct_start(struct netlink_callback *cb)
	{
	const struct nlattr *const attr = cb->data;
	struct nlattr *tb[NFACCT_FILTER_MAX + 1];
	struct nfacct_filter *filter;
	int err;

	if (!attr)
	return 0;

	err = nla_parse_nested_deprecated(tb, NFACCT_FILTER_MAX, attr,
	filter_policy, NULL);
	if (err < 0)
	return err;

	if (!tb[NFACCT_FILTER_MASK] \|\| !tb[NFACCT_FILTER_VALUE])
	return -EINVAL;

	filter = kzalloc(sizeof(struct nfacct_filter), GFP_KERNEL);
	if (!filter)
	return -ENOMEM;

	filter->mask = ntohl(nla_get_be32(tb[NFACCT_FILTER_MASK]));
	filter->value = ntohl(nla_get_be32(tb[NFACCT_FILTER_VALUE]));
	cb->data = filter;

	return 0;
	}

	static int nfnl_acct_get(struct sk_buff skb, const struct nfnl_info info,
	const struct nlattr * const tb[])
	{
	struct nfnl_acct_net *nfnl_acct_net = nfnl_acct_pernet(info->net);
	int ret = -ENOENT;
	struct nf_acct *cur;
	char *acct_name;

	if (info->nlh->nlmsg_flags & NLM_F_DUMP) {
	struct netlink_dump_control c = {
	.dump = nfnl_acct_dump,
	.start = nfnl_acct_start,
	.done = nfnl_acct_done,
	.data = (void *)tb[NFACCT_FILTER],
	};

	return netlink_dump_start(info->sk, skb, info->nlh, &c);
	}

	if (!tb[NFACCT_NAME])
	return -EINVAL;
	acct_name = nla_data(tb[NFACCT_NAME]);

	list_for_each_entry(cur, &nfnl_acct_net->nfnl_acct_list, head) {
	struct sk_buff *skb2;

	if (strncmp(cur->name, acct_name, NFACCT_NAME_MAX)!= 0)
	continue;

	skb2 = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
	if (skb2 == NULL) {
	ret = -ENOMEM;
	break;
	}

	ret = nfnl_acct_fill_info(skb2, NETLINK_CB(skb).portid,
	info->nlh->nlmsg_seq,
	NFNL_MSG_TYPE(info->nlh->nlmsg_type),
	NFNL_MSG_ACCT_NEW, cur);
	if (ret <= 0) {
	kfree_skb(skb2);
	break;
	}
	ret = netlink_unicast(info->sk, skb2, NETLINK_CB(skb).portid,
	MSG_DONTWAIT);
	if (ret > 0)
	ret = 0;

	/* this avoids a loop in nfnetlink. */
	return ret == -EAGAIN ? -ENOBUFS : ret;
	}
	return ret;
	}

	/* try to delete object, fail if it is still in use. */
	static int nfnl_acct_try_del(struct nf_acct *cur)
	{
	int ret = 0;

	/* We want to avoid races with nfnl_acct_put. So only when the current
	* refcnt is 1, we decrease it to 0.
	*/
	if (refcount_dec_if_one(&cur->refcnt)) {
	/* We are protected by nfnl mutex. */
	list_del_rcu(&cur->head);
	kfree_rcu(cur, rcu_head);
	} else {
	ret = -EBUSY;
	}
	return ret;
	}

	static int nfnl_acct_del(struct sk_buff skb, const struct nfnl_info info,
	const struct nlattr * const tb[])
	{
	struct nfnl_acct_net *nfnl_acct_net = nfnl_acct_pernet(info->net);
	struct nf_acct cur, tmp;
	int ret = -ENOENT;
	char *acct_name;

	if (!tb[NFACCT_NAME]) {
	list_for_each_entry_safe(cur, tmp, &nfnl_acct_net->nfnl_acct_list, head)
	nfnl_acct_try_del(cur);

	return 0;
	}
	acct_name = nla_data(tb[NFACCT_NAME]);

	list_for_each_entry(cur, &nfnl_acct_net->nfnl_acct_list, head) {
	if (strncmp(cur->name, acct_name, NFACCT_NAME_MAX) != 0)
	continue;

	ret = nfnl_acct_try_del(cur);
	if (ret < 0)
	return ret;

	break;
	}
	return ret;
	}

	static const struct nla_policy nfnl_acct_policy[NFACCT_MAX+1] = {
	[NFACCT_NAME] = { .type = NLA_NUL_STRING, .len = NFACCT_NAME_MAX-1 },
	[NFACCT_BYTES] = { .type = NLA_U64 },
	[NFACCT_PKTS] = { .type = NLA_U64 },
	[NFACCT_FLAGS] = { .type = NLA_U32 },
	[NFACCT_QUOTA] = { .type = NLA_U64 },
	[NFACCT_FILTER] = {.type = NLA_NESTED },
	};

	static const struct nfnl_callback nfnl_acct_cb[NFNL_MSG_ACCT_MAX] = {
	[NFNL_MSG_ACCT_NEW] = {
	.call = nfnl_acct_new,
	.type = NFNL_CB_MUTEX,
	.attr_count = NFACCT_MAX,
	.policy = nfnl_acct_policy
	},
	[NFNL_MSG_ACCT_GET] = {
	.call = nfnl_acct_get,
	.type = NFNL_CB_MUTEX,
	.attr_count = NFACCT_MAX,
	.policy = nfnl_acct_policy
	},
	[NFNL_MSG_ACCT_GET_CTRZERO] = {
	.call = nfnl_acct_get,
	.type = NFNL_CB_MUTEX,
	.attr_count = NFACCT_MAX,
	.policy = nfnl_acct_policy
	},
	[NFNL_MSG_ACCT_DEL] = {
	.call = nfnl_acct_del,
	.type = NFNL_CB_MUTEX,
	.attr_count = NFACCT_MAX,
	.policy = nfnl_acct_policy
	},
	};

	static const struct nfnetlink_subsystem nfnl_acct_subsys = {
	.name = "acct",
	.subsys_id = NFNL_SUBSYS_ACCT,
	.cb_count = NFNL_MSG_ACCT_MAX,
	.cb = nfnl_acct_cb,
	};

	MODULE_ALIAS_NFNL_SUBSYS(NFNL_SUBSYS_ACCT);

	struct nf_acct nfnl_acct_find_get(struct net net, const char *acct_name)
	{
	struct nfnl_acct_net *nfnl_acct_net = nfnl_acct_pernet(net);
	struct nf_acct cur, acct = NULL;

	rcu_read_lock();
	list_for_each_entry_rcu(cur, &nfnl_acct_net->nfnl_acct_list, head) {
	if (strncmp(cur->name, acct_name, NFACCT_NAME_MAX)!= 0)
	continue;

	if (!try_module_get(THIS_MODULE))
	goto err;

	if (!refcount_inc_not_zero(&cur->refcnt)) {
	module_put(THIS_MODULE);
	goto err;
	}

	acct = cur;
	break;
	}
	err:
	rcu_read_unlock();
	return acct;
	}
	EXPORT_SYMBOL_GPL(nfnl_acct_find_get);

	void nfnl_acct_put(struct nf_acct *acct)
	{
	if (refcount_dec_and_test(&acct->refcnt))
	kfree_rcu(acct, rcu_head);

	module_put(THIS_MODULE);
	}
	EXPORT_SYMBOL_GPL(nfnl_acct_put);

	void nfnl_acct_update(const struct sk_buff skb, struct nf_acct nfacct)
	{
	atomic64_inc(&nfacct->pkts);
	atomic64_add(skb->len, &nfacct->bytes);
	}
	EXPORT_SYMBOL_GPL(nfnl_acct_update);

	static void nfnl_overquota_report(struct net net, struct nf_acct nfacct)
	{
	int ret;
	struct sk_buff *skb;

	skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_ATOMIC);
	if (skb == NULL)
	return;

	ret = nfnl_acct_fill_info(skb, 0, 0, NFNL_MSG_ACCT_OVERQUOTA, 0,
	nfacct);
	if (ret <= 0) {
	kfree_skb(skb);
	return;
	}
	nfnetlink_broadcast(net, skb, 0, NFNLGRP_ACCT_QUOTA, GFP_ATOMIC);
	}

	int nfnl_acct_overquota(struct net net, struct nf_acct nfacct)
	{
	u64 now;
	u64 *quota;
	int ret = NFACCT_UNDERQUOTA;

	/* no place here if we don't have a quota */
	if (!(nfacct->flags & NFACCT_F_QUOTA))
	return NFACCT_NO_QUOTA;

	quota = (u64 *)nfacct->data;
	now = (nfacct->flags & NFACCT_F_QUOTA_PKTS) ?
	atomic64_read(&nfacct->pkts) : atomic64_read(&nfacct->bytes);

	ret = now > *quota;

	if (now >= *quota &&
	!test_and_set_bit(NFACCT_OVERQUOTA_BIT, &nfacct->flags)) {
	nfnl_overquota_report(net, nfacct);
	}

	return ret;
	}
	EXPORT_SYMBOL_GPL(nfnl_acct_overquota);

	static int __net_init nfnl_acct_net_init(struct net *net)
	{
	INIT_LIST_HEAD(&nfnl_acct_pernet(net)->nfnl_acct_list);

	return 0;
	}

	static void __net_exit nfnl_acct_net_exit(struct net *net)
	{
	struct nfnl_acct_net *nfnl_acct_net = nfnl_acct_pernet(net);
	struct nf_acct cur, tmp;

	list_for_each_entry_safe(cur, tmp, &nfnl_acct_net->nfnl_acct_list, head) {
	list_del_rcu(&cur->head);

	if (refcount_dec_and_test(&cur->refcnt))
	kfree_rcu(cur, rcu_head);
	}
	}

	static struct pernet_operations nfnl_acct_ops = {
	.init = nfnl_acct_net_init,
	.exit = nfnl_acct_net_exit,
	.id = &nfnl_acct_net_id,
	.size = sizeof(struct nfnl_acct_net),
	};

	static int __init nfnl_acct_init(void)
	{
	int ret;

	ret = register_pernet_subsys(&nfnl_acct_ops);
	if (ret < 0) {
	pr_err("nfnl_acct_init: failed to register pernet ops\n");
	goto err_out;
	}

	ret = nfnetlink_subsys_register(&nfnl_acct_subsys);
	if (ret < 0) {
	pr_err("nfnl_acct_init: cannot register with nfnetlink.\n");
	goto cleanup_pernet;
	}
	return 0;

	cleanup_pernet:
	unregister_pernet_subsys(&nfnl_acct_ops);
	err_out:
	return ret;
	}

	static void __exit nfnl_acct_exit(void)
	{
	nfnetlink_subsys_unregister(&nfnl_acct_subsys);
	unregister_pernet_subsys(&nfnl_acct_ops);
	}

	module_init(nfnl_acct_init);
	module_exit(nfnl_acct_exit);