path: root/net/netfilter/nfnetlink_queue.c

/*
 * This is a module which is used for queueing packets and communicating with
 * userspace via nfnetlink.
 *
 * (C) 2005 by Harald Welte <laforge@netfilter.org>
 * (C) 2007 by Patrick McHardy <kaber@trash.net>
 *
 * Based on the old ipv4-only ip_queue.c:
 * (C) 2000-2002 James Morris <jmorris@intercode.com.au>
 * (C) 2003-2005 Netfilter Core Team <coreteam@netfilter.org>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 */
#include <linux/module.h>
#include <linux/skbuff.h>
#include <linux/init.h>
#include <linux/spinlock.h>
#include <linux/slab.h>
#include <linux/notifier.h>
#include <linux/netdevice.h>
#include <linux/netfilter.h>
#include <linux/proc_fs.h>
#include <linux/netfilter_ipv4.h>
#include <linux/netfilter_ipv6.h>
#include <linux/netfilter/nfnetlink.h>
#include <linux/netfilter/nfnetlink_queue.h>
#include <linux/list.h>
#include <net/sock.h>
#include <net/netfilter/nf_queue.h>

#include <linux/atomic.h>

#ifdef CONFIG_BRIDGE_NETFILTER
#include "../bridge/br_private.h"
#endif

#define NFQNL_QMAX_DEFAULT 1024

struct nfqnl_instance {
	struct hlist_node hlist;		/* global list of queues */
	struct rcu_head rcu;

	int peer_pid;
	unsigned int queue_maxlen;
	unsigned int copy_range;
	unsigned int queue_dropped;
	unsigned int queue_user_dropped;


	u_int16_t queue_num;			/* number of this queue */
	u_int8_t copy_mode;
/*
 * Following fields are dirtied for each queued packet,
 * keep them in same cache line if possible.
 */
	spinlock_t	lock;
	unsigned int	queue_total;
	unsigned int	id_sequence;		/* 'sequence' of pkt ids */
	struct list_head queue_list;		/* packets in queue */
};

typedef int (*nfqnl_cmpfn)(struct nf_queue_entry *, unsigned long);

static DEFINE_SPINLOCK(instances_lock);

#define INSTANCE_BUCKETS	16
static struct hlist_head instance_table[INSTANCE_BUCKETS] __read_mostly;

static inline u_int8_t instance_hashfn(u_int16_t queue_num)
{
	return ((queue_num >> 8) | queue_num) % INSTANCE_BUCKETS;
}

static struct nfqnl_instance *
instance_lookup(u_int16_t queue_num)
{
	struct hlist_head *head;
	struct hlist_node *pos;
	struct nfqnl_instance *inst;

	head = &instance_table[instance_hashfn(queue_num)];
	hlist_for_each_entry_rcu(inst, pos, head, hlist) {
		if (inst->queue_num == queue_num)
			return inst;
	}
	return NULL;
}

static struct nfqnl_instance *
instance_create(u_int16_t queue_num, int pid)
{
	struct nfqnl_instance *inst;
	unsigned int h;
	int err;

	spin_lock(&instances_lock);
	if (instance_lookup(queue_num)) {
		err = -EEXIST;
		goto out_unlock;
	}

	inst = kzalloc(sizeof(*inst), GFP_ATOMIC);
	if (!inst) {
		err = -ENOMEM;
		goto out_unlock;
	}

	inst->queue_num = queue_num;
	inst->peer_pid = pid;
	inst->queue_maxlen = NFQNL_QMAX_DEFAULT;
	inst->copy_range = 0xfffff;
	inst->copy_mode = NFQNL_COPY_NONE;
	spin_lock_init(&inst->lock);
	INIT_LIST_HEAD(&inst->queue_list);

	if (!try_module_get(THIS_MODULE)) {
		err = -EAGAIN;
		goto out_free;
	}

	h = instance_hashfn(queue_num);
	hlist_add_head_rcu(&inst->hlist, &instance_table[h]);

	spin_unlock(&instances_lock);

	return inst;

out_free:
	kfree(inst);
out_unlock:
	spin_unlock(&instances_lock);
	return ERR_PTR(err);
}

static void nfqnl_flush(struct nfqnl_instance *queue, nfqnl_cmpfn cmpfn,
			unsigned long data);

static void
instance_destroy_rcu(struct rcu_head *head)
{
	struct nfqnl_instance *inst = container_of(head, struct nfqnl_instance,
						   rcu);

	nfqnl_flush(inst, NULL, 0);
	kfree(inst);
	module_put(THIS_MODULE);
}

static void
__instance_destroy(struct nfqnl_instance *inst)
{
	hlist_del_rcu(&inst->hlist);
	call_rcu(&inst->rcu, instance_destroy_rcu);
}

static void
instance_destroy(struct nfqnl_instance *inst)
{
	spin_lock(&instances_lock);
	__instance_destroy(inst);
	spin_unlock(&instances_lock);
}

static inline void
__enqueue_entry(struct nfqnl_instance *queue, struct nf_queue_entry *entry)
{
       list_add_tail(&entry->list, &queue->queue_list);
       queue<