path: root/net/netfilter/nfnetlink_queue.c

/*
 * This is a module which is used for queueing packets and communicating with
 * userspace via nfetlink.
 *
 * (C) 2005 by Harald Welte <laforge@netfilter.org>
 *
 * 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/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 <asm/atomic.h>

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

#define NFQNL_QMAX_DEFAULT 1024

#if 0
#define QDEBUG(x, args ...)	printk(KERN_DEBUG "%s(%d):%s():	" x, 	   \
					__FILE__, __LINE__, __FUNCTION__,  \
					## args)
#else
#define QDEBUG(x, ...)
#endif

struct nfqnl_queue_entry {
	struct list_head list;
	struct nf_info *info;
	struct sk_buff *skb;
	unsigned int id;
};

struct nfqnl_instance {
	struct hlist_node hlist;		/* global list of queues */
	atomic_t use;

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

	atomic_t id_sequence;			/* 'sequence' of pkt ids */

	u_int16_t queue_num;			/* number of this queue */
	u_int8_t copy_mode;

	spinlock_t lock;

	struct list_head queue_list;		/* packets in queue */
};

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

static DEFINE_RWLOCK(instances_lock);

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

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(inst, pos, head, hlist) {
		if (inst->queue_num == queue_num)
			return inst;
	}
	return NULL;
}

static struct nfqnl_instance *
instance_lookup_get(u_int16_t queue_num)
{
	struct nfqnl_instance *inst;

	read_lock_bh(&instances_lock);
	inst = __instance_lookup(queue_num);
	if (inst)
		atomic_inc(&inst->use);
	read_unlock_bh(&instances_lock);

	return inst;
}

static void
instance_put(struct nfqnl_instance *inst)
{
	if (inst && atomic_dec_and_test(&inst->use)) {
		QDEBUG("kfree(inst=%p)\n", inst);
		kfree(inst);
	}
}

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

	QDEBUG("entering for queue_num=%u, pid=%d\n", queue_num, pid);

	write_lock_bh(&instances_lock);	
	if (__instance_lookup(queue_num)) {
		inst = NULL;
		QDEBUG("aborting, instance already exists\n");
		goto out_unlock;
	}

	inst = kzalloc(sizeof(*inst), GFP_ATOMIC);
	if (!inst)
		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;
	atomic_set(&inst->id_sequence, 0);
	/* needs to be two, since we _put() after creation */
	atomic_set(&inst->use, 2);
	spin_lock_init(&inst->