[deliverable/linux.git] / net / ipv4 / netfilter / ipt_recent.c

/*
 * Copyright (c) 2006 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 version 2 as
 * published by the Free Software Foundation.
 *
 * This is a replacement of the old ipt_recent module, which carried the
 * following copyright notice:
 *
 * Author: Stephen Frost <sfrost@snowman.net>
 * Copyright 2002-2003, Stephen Frost, 2.5.x port by laforge@netfilter.org
 */
#include <linux/init.h>
#include <linux/moduleparam.h>
#include <linux/proc_fs.h>
#include <linux/seq_file.h>
#include <linux/string.h>
#include <linux/ctype.h>
#include <linux/list.h>
#include <linux/random.h>
#include <linux/jhash.h>
#include <linux/bitops.h>
#include <linux/skbuff.h>
#include <linux/inet.h>

#include <linux/netfilter_ipv4/ip_tables.h>
#include <linux/netfilter_ipv4/ipt_recent.h>

MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");
MODULE_DESCRIPTION("IP tables recently seen matching module");
MODULE_LICENSE("GPL");

static unsigned int ip_list_tot = 100;
static unsigned int ip_pkt_list_tot = 20;
static unsigned int ip_list_hash_size = 0;
static unsigned int ip_list_perms = 0644;
module_param(ip_list_tot, uint, 0400);
module_param(ip_pkt_list_tot, uint, 0400);
module_param(ip_list_hash_size, uint, 0400);
module_param(ip_list_perms, uint, 0400);
MODULE_PARM_DESC(ip_list_tot, "number of IPs to remember per list");
MODULE_PARM_DESC(ip_pkt_list_tot, "number of packets per IP to remember (max. 255)");
MODULE_PARM_DESC(ip_list_hash_size, "size of hash table used to look up IPs");
MODULE_PARM_DESC(ip_list_perms, "permissions on /proc/net/ipt_recent/* files");


struct recent_entry {
	struct list_head	list;
	struct list_head	lru_list;
	u_int32_t		addr;
	u_int8_t		ttl;
	u_int8_t		index;
	u_int16_t		nstamps;
	unsigned long		stamps[0];
};

struct recent_table {
	struct list_head	list;
	char			name[IPT_RECENT_NAME_LEN];
#ifdef CONFIG_PROC_FS
	struct proc_dir_entry	*proc;
#endif
	unsigned int		refcnt;
	unsigned int		entries;
	struct list_head	lru_list;
	struct list_head	iphash[0];
};

static LIST_HEAD(tables);
static DEFINE_SPINLOCK(recent_lock);
static DEFINE_MUTEX(recent_mutex);

#ifdef CONFIG_PROC_FS
static struct proc_dir_entry	*proc_dir;
static struct file_operations	recent_fops;
#endif

static u_int32_t hash_rnd;
static int hash_rnd_initted;

static unsigned int recent_entry_hash(u_int32_t addr)
{
	if (!hash_rnd_initted) {
		get_random_bytes(&hash_rnd, 4);
		hash_rnd_initted = 1;
	}
	return jhash_1word(addr, hash_rnd) & (ip_list_hash_size - 1);
}

static struct recent_entry *
recent_entry_lookup(const struct recent_table *table, u_int32_t addr, u_int8_t ttl)
{
	struct recent_entry *e;
	unsigned int h;

	h = recent_entry_hash(addr);
	list_for_each_entry(e, &table->iphash[h], list)
		if (e->addr == addr && (ttl == e->ttl || !ttl || !e->ttl))
			return e;
	return NULL;
}

static void recent_entry_remove(struct recent_table *t, struct recent_entry *e)
{
	list_del(&e->list);
	list_del(&e->lru_list);
	kfree(e);
	t->entries--;
}

static struct recent_entry *
recent_entry_init(struct recent_table *t, u_int32_t addr, u_int8_t ttl)
{
	struct recent_entry *e;

	if (t->entries >= ip_list_tot) {
		e = list_entry(t->lru_list.next, struct recent_entry, lru_list);
		recent_entry_remove(t, e);
	}
	e = kmalloc(sizeof(*e) + sizeof(e->stamps[0]) * ip_pkt_list_tot,
		    GFP_ATOMIC);
	if (e == NULL)
		return NULL;
	e->addr      = addr;
	e->ttl       = ttl;
	e->stamps[0] = jiffies;
	e->nstamps   = 1;
	e->index     = 1;
	list_add_tail(&e->list, &t->iphash[recent_entry_hash(addr)]);
	list_add_tail(&e->lru_list, &t->lru_list);
	t->entries++;
	return e;
}

static void recent_entry_update(struct recent_table *t, struct recent_entry *e)
{
	e->stamps[e->index++] = jiffies;
	if (e->index > e->nstamps)
		e->nstamps = e->index;
	e->index %= ip_pkt_list_tot;
	list_move_tail(&e->lru_list, &t->lru_list);
}

static struct recent_table *recent_table_lookup(const char *name)
{
	struct recent_table *t;

	list_for_each_entry(t, &tables, list)
		if (!strcmp(t->name, name))
			return t;
	return NULL;
}

static void recent_table_flush(struct recent_table *t)
{
	struct recent_entry *e, *next;
	unsigned int i;

	for (i = 0; i < ip_list_hash_size; i++) {
		list_for_each_entry_safe(e, next, &t->iphash[i], list)
			recent_entry_remove(t, e);
	}
}

static int
ipt_recent_match(const struct sk_buff *skb,
		 const struct net_device *in, const struct net_device *out,
		 const struct xt_match *match, const void *matchinfo,
		 int offset, unsigned int protoff, int *hotdrop)
{
	const struct ipt_recent_info *info = matchinfo;
	struct recent_table *t;
	struct recent_entry *e;
	u_int32_t addr;
	u_int8_t ttl;
	int ret = info->invert;

	if (info->side == IPT_RECENT_DEST)
		addr = skb->nh.iph->daddr;
	else
		addr = skb->nh.iph->saddr;

	ttl = skb->nh.iph->ttl;
	/* use TTL as seen before forwarding */
	if (out && !skb->sk)
		ttl++;

	spin_lock_bh(&recent_lock);
	t = recent_table_lookup(info->name);
	e = recent_entry_lookup(t, addr,
				info->check_set & IPT_RECENT_TTL ? ttl : 0);
	if (e == NULL) {
		if (!(info->check_set & IPT_RECENT_SET))
			goto out;
		e = recent_entry_init(t, addr, ttl);
		if (e == NULL)
			*hotdrop = 1;
		ret ^= 1;
		goto out;
	}

	if (info->check_set & IPT_RECENT_SET)
		ret ^= 1;
	else if (info->check_set & IPT_RECENT_REMOVE) {
		recent_entry_remove(t, e);
		ret ^= 1;
	} else if (info->check_set & (IPT_RECENT_CHECK | IPT_RECENT_UPDATE)) {
		unsigned long t = jiffies - info->seconds * HZ;
		unsigned int i, hits = 0;

		for (i = 0; i < e->nstamps; i++) {
			if (info->seconds && time_after(t, e->stamps[i]))
				continue;
			if (++hits >= info->hit_count) {
				ret ^= 1;
				break;
			}
		}
	}

	if (info->check_set & IPT_RECENT_SET ||
	    (info->check_set & IPT_RECENT_UPDATE && ret)) {
		recent_entry_update(t, e);
		e->ttl = ttl;
	}
out:
	spin_unlock_bh(&recent_lock);
	return ret;
}

static int
ipt_recent_checkentry(const char *tablename, const void *ip,
		      const struct xt_match *match, void *matchinfo,
		      unsigned int matchsize, unsigned int hook_mask)
{
	const struct ipt_recent_info *info = matchinfo;
	struct recent_table *t;
	unsigned i;
	int ret = 0;

	if (hweight8(info->check_set &
		     (IPT_RECENT_SET | IPT_RECENT_REMOVE |
		      IPT_RECENT_CHECK | IPT_RECENT_UPDATE)) != 1)
		return 0;
	if ((info->check_set & (IPT_RECENT_SET | IPT_RECENT_REMOVE)) &&
	    (info->seconds || info->hit_count))
		return 0;
	if (info->name[0] == '\0' ||
	    strnlen(info->name, IPT_RECENT_NAME_LEN) == IPT_RECENT_NAME_LEN)
		return 0;

	mutex_lock(&recent_mutex);
	t = recent_table_lookup(info->name);
	if (t != NULL) {
		t->refcnt++;
		ret = 1;
		goto out;
	}

	t = kzalloc(sizeof(*t) + sizeof(t->iphash[0]) * ip_list_hash_size,
		    GFP_KERNEL);
	if (t == NULL)
		goto out;
	strcpy(t->name, info->name);
	INIT_LIST_HEAD(&t->lru_list);
	for (i = 0; i < ip_list_hash_size; i++)
		INIT_LIST_HEAD(&t->iphash[i]);
#ifdef CONFIG_PROC_FS
	t->proc = create_proc_entry(t->name, ip_list_perms, proc_dir);
	if (t->proc == NULL) {
		kfree(t);
		goto out;
	}
	t->proc->proc_fops = &recent_fops;
	t->proc->data      = t;
#endif
	spin_lock_bh(&recent_lock);
	list_add_tail(&t->list, &tables);
	spin_unlock_bh(&recent_lock);
	ret = 1;
out:
	mutex_unlock(&recent_mutex);
	return ret;
}

static void
ipt_recent_destroy(const struct xt_match *match, void *matchinfo,
		   unsigned int matchsize)
{
	const struct ipt_recent_info *info = matchinfo;
	struct recent_table *t;

	mutex_lock(&recent_mutex);
	t = recent_table_lookup(info->name);
	if (--t->refcnt == 0) {
		spin_lock_bh(&recent_lock);
		list_del(&t->list);
		spin_unlock_bh(&recent_lock);
		recent_table_flush(t);
#ifdef CONFIG_PROC_FS
		remove_proc_entry(t->name, proc_dir);
#endif
		kfree(t);
	}
	mutex_unlock(&recent_mutex);
}

#ifdef CONFIG_PROC_FS
struct recent_iter_state {
	struct recent_table	*table;
	unsigned int		bucket;
};

static void *recent_seq_start(struct seq_file *seq, loff_t *pos)
{
	struct recent_iter_state *st = seq->private;
	struct recent_table *t = st->table;
	struct recent_entry *e;
	loff_t p = *pos;

	spin_lock_bh(&recent_lock);

	for (st->bucket = 0; st->bucket < ip_list_hash_size; st->bucket++) {
		list_for_each_entry(e, &t->iphash[st->bucket], list) {
			if (p-- == 0)
				return e;
		}
	}
	return NULL;
}

static void *recent_seq_next(struct seq_file *seq, void *v, loff_t *pos)
{
	struct recent_iter_state *st = seq->private;
	struct recent_table *t = st->table;
	struct recent_entry *e = v;
	struct list_head *head = e->list.next;

	while (head == &t->iphash[st->bucket]) {
		if (++st->bucket >= ip_list_hash_size)
			return NULL;
		head = t->iphash[st->bucket].next;
	}
	(*pos)++;
	return list_entry(head, struct recent_entry, list);
}

static void recent_seq_stop(struct seq_file *s, void *v)
{
	spin_unlock_bh(&recent_lock);
}

static int recent_seq_show(struct seq_file *seq, void *v)
{
	struct recent_entry *e = v;
	unsigned int i;

	i = (e->index - 1) % ip_pkt_list_tot;
	seq_printf(seq, "src=%u.%u.%u.%u ttl: %u last_seen: %lu oldest_pkt: %u",
		   NIPQUAD(e->addr), e->ttl, e->stamps[i], e->index);
	for (i = 0; i < e->nstamps; i++)
		seq_printf(seq, "%s %lu", i ? "," : "", e->stamps[i]);
	seq_printf(seq, "\n");
	return 0;
}

static struct seq_operations recent_seq_ops = {
	.start		= recent_seq_start,
	.next		= recent_seq_next,
	.stop		= recent_seq_stop,
	.show		= recent_seq_show,
};

static int recent_seq_open(struct inode *inode, struct file *file)
{
	struct proc_dir_entry *pde = PDE(inode);
	struct seq_file *seq;
	struct recent_iter_state *st;
	int ret;

	st = kzalloc(sizeof(*st), GFP_KERNEL);
	if (st == NULL)
		return -ENOMEM;
	ret = seq_open(file, &recent_seq_ops);
	if (ret)
		kfree(st);
	st->table    = pde->data;
	seq          = file->private_data;
	seq->private = st;
	return ret;
}

static ssize_t recent_proc_write(struct file *file, const char __user *input,
				 size_t size, loff_t *loff)
{
	struct proc_dir_entry *pde = PDE(file->f_dentry->d_inode);
	struct recent_table *t = pde->data;
	struct recent_entry *e;
	char buf[sizeof("+255.255.255.255")], *c = buf;
	u_int32_t addr;
	int add;

	if (size > sizeof(buf))
		size = sizeof(buf);
	if (copy_from_user(buf, input, size))
		return -EFAULT;
	while (isspace(*c))
		c++;

	if (size - (c - buf) < 5)
		return c - buf;
	if (!strncmp(c, "clear", 5)) {
		c += 5;
		spin_lock_bh(&recent_lock);
		recent_table_flush(t);
		spin_unlock_bh(&recent_lock);
		return c - buf;
	}

	switch (*c) {
	case '-':
		add = 0;
		c++;
		break;
	case '+':
		c++;
	default:
		add = 1;
		break;
	}
	addr = in_aton(c);

	spin_lock_bh(&recent_lock);
	e = recent_entry_lookup(t, addr, 0);
	if (e == NULL) {
		if (add)
			recent_entry_init(t, addr, 0);
	} else {
		if (add)
			recent_entry_update(t, e);
		else
			recent_entry_remove(t, e);
	}
	spin_unlock_bh(&recent_lock);
	return size;
}

static struct file_operations recent_fops = {
	.open		= recent_seq_open,
	.read		= seq_read,
	.write		= recent_proc_write,
	.release	= seq_release_private,
	.owner		= THIS_MODULE,
};
#endif /* CONFIG_PROC_FS */

static struct ipt_match recent_match = {
	.name		= "recent",
	.match		= ipt_recent_match,
	.matchsize	= sizeof(struct ipt_recent_info),
	.checkentry	= ipt_recent_checkentry,
	.destroy	= ipt_recent_destroy,
	.me		= THIS_MODULE,
};

static int __init ipt_recent_init(void)
{
	int err;

	if (!ip_list_tot || !ip_pkt_list_tot || ip_pkt_list_tot > 255)
		return -EINVAL;
	ip_list_hash_size = 1 << fls(ip_list_tot);

	err = ipt_register_match(&recent_match);
#ifdef CONFIG_PROC_FS
	if (err)
		return err;
	proc_dir = proc_mkdir("ipt_recent", proc_net);
	if (proc_dir == NULL) {
		ipt_unregister_match(&recent_match);
		err = -ENOMEM;
	}
#endif
	return err;
}

static void __exit ipt_recent_exit(void)
{
	BUG_ON(!list_empty(&tables));
	ipt_unregister_match(&recent_match);
#ifdef CONFIG_PROC_FS
	remove_proc_entry("ipt_recent", proc_net);
#endif
}

module_init(ipt_recent_init);
module_exit(ipt_recent_exit);
Commit	Line	Data
404bdbfd PM	1	/*
	2	* Copyright (c) 2006 Patrick McHardy <kaber@trash.net>
	3	*
	4	* This program is free software; you can redistribute it and/or modify
	5	* it under the terms of the GNU General Public License version 2 as
	6	* published by the Free Software Foundation.
	7	*
	8	* This is a replacement of the old ipt_recent module, which carried the
	9	* following copyright notice:
	10	*
	11	* Author: Stephen Frost <sfrost@snowman.net>
	12	* Copyright 2002-2003, Stephen Frost, 2.5.x port by laforge@netfilter.org
	13	*/
	14	#include <linux/init.h>
	15	#include <linux/moduleparam.h>
1da177e4	16	#include <linux/proc_fs.h>
404bdbfd PM	17	#include <linux/seq_file.h>
404bdbfd PM	18	#include <linux/string.h>
1da177e4	19	#include <linux/ctype.h>
404bdbfd PM	20	#include <linux/list.h>
	21	#include <linux/random.h>
	22	#include <linux/jhash.h>
	23	#include <linux/bitops.h>
	24	#include <linux/skbuff.h>
	25	#include <linux/inet.h>
1da177e4 LT	26
	27	#include <linux/netfilter_ipv4/ip_tables.h>
	28	#include <linux/netfilter_ipv4/ipt_recent.h>
	29
404bdbfd PM	30	MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");
	31	MODULE_DESCRIPTION("IP tables recently seen matching module");
	32	MODULE_LICENSE("GPL");
1da177e4	33
e7be6994 PM	34	static unsigned int ip_list_tot = 100;
	35	static unsigned int ip_pkt_list_tot = 20;
	36	static unsigned int ip_list_hash_size = 0;
	37	static unsigned int ip_list_perms = 0644;
e7be6994 PM	38	module_param(ip_list_tot, uint, 0400);
	39	module_param(ip_pkt_list_tot, uint, 0400);
	40	module_param(ip_list_hash_size, uint, 0400);
	41	module_param(ip_list_perms, uint, 0400);
404bdbfd PM	42	MODULE_PARM_DESC(ip_list_tot, "number of IPs to remember per list");
	43	MODULE_PARM_DESC(ip_pkt_list_tot, "number of packets per IP to remember (max. 255)");
	44	MODULE_PARM_DESC(ip_list_hash_size, "size of hash table used to look up IPs");
	45	MODULE_PARM_DESC(ip_list_perms, "permissions on /proc/net/ipt_recent/* files");
	46
	47
	48	struct recent_entry {
	49	struct list_head list;
	50	struct list_head lru_list;
	51	u_int32_t addr;
	52	u_int8_t ttl;
	53	u_int8_t index;
	54	u_int16_t nstamps;
	55	unsigned long stamps[0];
1da177e4 LT	56	};
1da177e4 LT	57
404bdbfd PM	58	struct recent_table {
	59	struct list_head list;
	60	char name[IPT_RECENT_NAME_LEN];
1da177e4	61	#ifdef CONFIG_PROC_FS
404bdbfd PM	62	struct proc_dir_entry *proc;
	63	#endif
	64	unsigned int refcnt;
	65	unsigned int entries;
	66	struct list_head lru_list;
	67	struct list_head iphash[0];
1da177e4 LT	68	};
1da177e4 LT	69
404bdbfd	70	static LIST_HEAD(tables);
1da177e4	71	static DEFINE_SPINLOCK(recent_lock);
a0e889bb	72	static DEFINE_MUTEX(recent_mutex);
1da177e4 LT	73
1da177e4 LT	74	#ifdef CONFIG_PROC_FS
404bdbfd PM	75	static struct proc_dir_entry *proc_dir;
404bdbfd PM	76	static struct file_operations recent_fops;
1da177e4 LT	77	#endif
1da177e4 LT	78
404bdbfd PM	79	static u_int32_t hash_rnd;
404bdbfd PM	80	static int hash_rnd_initted;
1da177e4	81
404bdbfd	82	static unsigned int recent_entry_hash(u_int32_t addr)
1da177e4	83	{
404bdbfd PM	84	if (!hash_rnd_initted) {
	85	get_random_bytes(&hash_rnd, 4);
	86	hash_rnd_initted = 1;
1da177e4	87	}
404bdbfd	88	return jhash_1word(addr, hash_rnd) & (ip_list_hash_size - 1);
1da177e4 LT	89	}
1da177e4 LT	90
404bdbfd PM	91	static struct recent_entry *
404bdbfd PM	92	recent_entry_lookup(const struct recent_table *table, u_int32_t addr, u_int8_t ttl)
1da177e4	93	{
404bdbfd PM	94	struct recent_entry *e;
	95	unsigned int h;
	96
	97	h = recent_entry_hash(addr);
	98	list_for_each_entry(e, &table->iphash[h], list)
	99	if (e->addr == addr && (ttl == e->ttl \|\| !ttl \|\| !e->ttl))
	100	return e;
	101	return NULL;
	102	}
1da177e4	103
404bdbfd PM	104	static void recent_entry_remove(struct recent_table t, struct recent_entry e)
	105	{
	106	list_del(&e->list);
	107	list_del(&e->lru_list);
	108	kfree(e);
	109	t->entries--;
	110	}
1da177e4	111
404bdbfd PM	112	static struct recent_entry *
	113	recent_entry_init(struct recent_table *t, u_int32_t addr, u_int8_t ttl)
	114	{
	115	struct recent_entry *e;
1da177e4	116
404bdbfd PM	117	if (t->entries >= ip_list_tot) {
	118	e = list_entry(t->lru_list.next, struct recent_entry, lru_list);
	119	recent_entry_remove(t, e);
1da177e4	120	}
404bdbfd PM	121	e = kmalloc(sizeof(e) + sizeof(e->stamps[0]) ip_pkt_list_tot,
	122	GFP_ATOMIC);
	123	if (e == NULL)
	124	return NULL;
	125	e->addr = addr;
	126	e->ttl = ttl;
	127	e->stamps[0] = jiffies;
	128	e->nstamps = 1;
	129	e->index = 1;
	130	list_add_tail(&e->list, &t->iphash[recent_entry_hash(addr)]);
	131	list_add_tail(&e->lru_list, &t->lru_list);
	132	t->entries++;
	133	return e;
	134	}
1da177e4	135
404bdbfd PM	136	static void recent_entry_update(struct recent_table t, struct recent_entry e)
	137	{
	138	e->stamps[e->index++] = jiffies;
	139	if (e->index > e->nstamps)
	140	e->nstamps = e->index;
	141	e->index %= ip_pkt_list_tot;
	142	list_move_tail(&e->lru_list, &t->lru_list);
	143	}
1da177e4	144
404bdbfd PM	145	static struct recent_table recent_table_lookup(const char name)
	146	{
	147	struct recent_table *t;
1da177e4	148
404bdbfd PM	149	list_for_each_entry(t, &tables, list)
	150	if (!strcmp(t->name, name))
	151	return t;
	152	return NULL;
	153	}
1da177e4	154
404bdbfd PM	155	static void recent_table_flush(struct recent_table *t)
	156	{
	157	struct recent_entry e, next;
	158	unsigned int i;
1da177e4	159
404bdbfd PM	160	for (i = 0; i < ip_list_hash_size; i++) {
	161	list_for_each_entry_safe(e, next, &t->iphash[i], list)
	162	recent_entry_remove(t, e);
1da177e4	163	}
1da177e4 LT	164	}
1da177e4 LT	165
1da177e4	166	static int
404bdbfd PM	167	ipt_recent_match(const struct sk_buff *skb,
	168	const struct net_device in, const struct net_device out,
	169	const struct xt_match match, const void matchinfo,
	170	int offset, unsigned int protoff, int *hotdrop)
1da177e4	171	{
1da177e4	172	const struct ipt_recent_info *info = matchinfo;
404bdbfd PM	173	struct recent_table *t;
	174	struct recent_entry *e;
	175	u_int32_t addr;
	176	u_int8_t ttl;
	177	int ret = info->invert;
1da177e4	178
404bdbfd PM	179	if (info->side == IPT_RECENT_DEST)
	180	addr = skb->nh.iph->daddr;
	181	else
	182	addr = skb->nh.iph->saddr;
1da177e4	183
404bdbfd PM	184	ttl = skb->nh.iph->ttl;
	185	/* use TTL as seen before forwarding */
	186	if (out && !skb->sk)
	187	ttl++;
1da177e4	188
1da177e4	189	spin_lock_bh(&recent_lock);
404bdbfd PM	190	t = recent_table_lookup(info->name);
	191	e = recent_entry_lookup(t, addr,
	192	info->check_set & IPT_RECENT_TTL ? ttl : 0);
	193	if (e == NULL) {
	194	if (!(info->check_set & IPT_RECENT_SET))
	195	goto out;
	196	e = recent_entry_init(t, addr, ttl);
	197	if (e == NULL)
	198	*hotdrop = 1;
	199	ret ^= 1;
	200	goto out;
1da177e4 LT	201	}
1da177e4 LT	202
404bdbfd PM	203	if (info->check_set & IPT_RECENT_SET)
	204	ret ^= 1;
	205	else if (info->check_set & IPT_RECENT_REMOVE) {
	206	recent_entry_remove(t, e);
	207	ret ^= 1;
	208	} else if (info->check_set & (IPT_RECENT_CHECK \| IPT_RECENT_UPDATE)) {
	209	unsigned long t = jiffies - info->seconds * HZ;
	210	unsigned int i, hits = 0;
	211
	212	for (i = 0; i < e->nstamps; i++) {
	213	if (info->seconds && time_after(t, e->stamps[i]))
	214	continue;
	215	if (++hits >= info->hit_count) {
	216	ret ^= 1;
	217	break;
1da177e4	218	}
1da177e4	219	}
1da177e4 LT	220	}
1da177e4 LT	221
404bdbfd PM	222	if (info->check_set & IPT_RECENT_SET \|\|
	223	(info->check_set & IPT_RECENT_UPDATE && ret)) {
	224	recent_entry_update(t, e);
	225	e->ttl = ttl;
	226	}
	227	out:
	228	spin_unlock_bh(&recent_lock);
	229	return ret;
1da177e4 LT	230	}
1da177e4 LT	231
1da177e4	232	static int
404bdbfd PM	233	ipt_recent_checkentry(const char tablename, const void ip,
	234	const struct xt_match match, void matchinfo,
	235	unsigned int matchsize, unsigned int hook_mask)
1da177e4	236	{
1da177e4	237	const struct ipt_recent_info *info = matchinfo;
404bdbfd PM	238	struct recent_table *t;
	239	unsigned i;
	240	int ret = 0;
1da177e4	241
404bdbfd PM	242	if (hweight8(info->check_set &
	243	(IPT_RECENT_SET \| IPT_RECENT_REMOVE \|
	244	IPT_RECENT_CHECK \| IPT_RECENT_UPDATE)) != 1)
	245	return 0;
	246	if ((info->check_set & (IPT_RECENT_SET \| IPT_RECENT_REMOVE)) &&
	247	(info->seconds \|\| info->hit_count))
	248	return 0;
	249	if (info->name[0] == '\0' \|\|
	250	strnlen(info->name, IPT_RECENT_NAME_LEN) == IPT_RECENT_NAME_LEN)
	251	return 0;
1da177e4	252
a0e889bb	253	mutex_lock(&recent_mutex);
404bdbfd PM	254	t = recent_table_lookup(info->name);
	255	if (t != NULL) {
	256	t->refcnt++;
	257	ret = 1;
	258	goto out;
1da177e4 LT	259	}
1da177e4 LT	260
404bdbfd	261	t = kzalloc(sizeof(t) + sizeof(t->iphash[0]) ip_list_hash_size,
a0e889bb	262	GFP_KERNEL);
404bdbfd PM	263	if (t == NULL)
	264	goto out;
	265	strcpy(t->name, info->name);
	266	INIT_LIST_HEAD(&t->lru_list);
	267	for (i = 0; i < ip_list_hash_size; i++)
	268	INIT_LIST_HEAD(&t->iphash[i]);
	269	#ifdef CONFIG_PROC_FS
	270	t->proc = create_proc_entry(t->name, ip_list_perms, proc_dir);
	271	if (t->proc == NULL) {
	272	kfree(t);
	273	goto out;
1da177e4	274	}
404bdbfd PM	275	t->proc->proc_fops = &recent_fops;
404bdbfd PM	276	t->proc->data = t;
1da177e4	277	#endif
a0e889bb	278	spin_lock_bh(&recent_lock);
404bdbfd	279	list_add_tail(&t->list, &tables);
a0e889bb	280	spin_unlock_bh(&recent_lock);
404bdbfd PM	281	ret = 1;
404bdbfd PM	282	out:
a0e889bb	283	mutex_unlock(&recent_mutex);
404bdbfd PM	284	return ret;
404bdbfd PM	285	}
1da177e4	286
404bdbfd PM	287	static void
	288	ipt_recent_destroy(const struct xt_match match, void matchinfo,
	289	unsigned int matchsize)
	290	{
	291	const struct ipt_recent_info *info = matchinfo;
	292	struct recent_table *t;
1da177e4	293
a0e889bb	294	mutex_lock(&recent_mutex);
404bdbfd PM	295	t = recent_table_lookup(info->name);
404bdbfd PM	296	if (--t->refcnt == 0) {
a0e889bb	297	spin_lock_bh(&recent_lock);
404bdbfd	298	list_del(&t->list);
a0e889bb	299	spin_unlock_bh(&recent_lock);
404bdbfd PM	300	recent_table_flush(t);
	301	#ifdef CONFIG_PROC_FS
	302	remove_proc_entry(t->name, proc_dir);
1da177e4	303	#endif
404bdbfd	304	kfree(t);
1da177e4	305	}
a0e889bb	306	mutex_unlock(&recent_mutex);
404bdbfd	307	}
1da177e4	308
404bdbfd PM	309	#ifdef CONFIG_PROC_FS
	310	struct recent_iter_state {
	311	struct recent_table *table;
	312	unsigned int bucket;
	313	};
1da177e4	314
404bdbfd PM	315	static void recent_seq_start(struct seq_file seq, loff_t *pos)
	316	{
	317	struct recent_iter_state *st = seq->private;
	318	struct recent_table *t = st->table;
	319	struct recent_entry *e;
	320	loff_t p = *pos;
1da177e4	321
1da177e4	322	spin_lock_bh(&recent_lock);
1da177e4	323
404bdbfd PM	324	for (st->bucket = 0; st->bucket < ip_list_hash_size; st->bucket++) {
	325	list_for_each_entry(e, &t->iphash[st->bucket], list) {
	326	if (p-- == 0)
	327	return e;
1da177e4	328	}
1da177e4	329	}
404bdbfd PM	330	return NULL;
404bdbfd PM	331	}
1da177e4	332
404bdbfd PM	333	static void recent_seq_next(struct seq_file seq, void v, loff_t pos)
	334	{
	335	struct recent_iter_state *st = seq->private;
	336	struct recent_table *t = st->table;
	337	struct recent_entry *e = v;
	338	struct list_head *head = e->list.next;
	339
	340	while (head == &t->iphash[st->bucket]) {
	341	if (++st->bucket >= ip_list_hash_size)
	342	return NULL;
	343	head = t->iphash[st->bucket].next;
	344	}
	345	(*pos)++;
	346	return list_entry(head, struct recent_entry, list);
1da177e4 LT	347	}
1da177e4 LT	348
404bdbfd	349	static void recent_seq_stop(struct seq_file s, void v)
1da177e4	350	{
404bdbfd PM	351	spin_unlock_bh(&recent_lock);
404bdbfd PM	352	}
1da177e4	353
404bdbfd PM	354	static int recent_seq_show(struct seq_file seq, void v)
	355	{
	356	struct recent_entry *e = v;
	357	unsigned int i;
	358
	359	i = (e->index - 1) % ip_pkt_list_tot;
	360	seq_printf(seq, "src=%u.%u.%u.%u ttl: %u last_seen: %lu oldest_pkt: %u",
	361	NIPQUAD(e->addr), e->ttl, e->stamps[i], e->index);
	362	for (i = 0; i < e->nstamps; i++)
	363	seq_printf(seq, "%s %lu", i ? "," : "", e->stamps[i]);
	364	seq_printf(seq, "\n");
	365	return 0;
	366	}
1da177e4	367
404bdbfd PM	368	static struct seq_operations recent_seq_ops = {
	369	.start = recent_seq_start,
	370	.next = recent_seq_next,
	371	.stop = recent_seq_stop,
	372	.show = recent_seq_show,
	373	};
1da177e4	374
404bdbfd PM	375	static int recent_seq_open(struct inode inode, struct file file)
	376	{
	377	struct proc_dir_entry *pde = PDE(inode);
	378	struct seq_file *seq;
	379	struct recent_iter_state *st;
	380	int ret;
	381
	382	st = kzalloc(sizeof(*st), GFP_KERNEL);
	383	if (st == NULL)
	384	return -ENOMEM;
	385	ret = seq_open(file, &recent_seq_ops);
	386	if (ret)
	387	kfree(st);
	388	st->table = pde->data;
	389	seq = file->private_data;
	390	seq->private = st;
	391	return ret;
	392	}
1da177e4	393
404bdbfd PM	394	static ssize_t recent_proc_write(struct file file, const char __user input,
	395	size_t size, loff_t *loff)
	396	{
	397	struct proc_dir_entry *pde = PDE(file->f_dentry->d_inode);
	398	struct recent_table *t = pde->data;
	399	struct recent_entry *e;
	400	char buf[sizeof("+255.255.255.255")], *c = buf;
	401	u_int32_t addr;
	402	int add;
	403
	404	if (size > sizeof(buf))
	405	size = sizeof(buf);
	406	if (copy_from_user(buf, input, size))
	407	return -EFAULT;
	408	while (isspace(*c))
	409	c++;
	410
	411	if (size - (c - buf) < 5)
	412	return c - buf;
	413	if (!strncmp(c, "clear", 5)) {
	414	c += 5;
	415	spin_lock_bh(&recent_lock);
	416	recent_table_flush(t);
1da177e4	417	spin_unlock_bh(&recent_lock);
404bdbfd	418	return c - buf;
1da177e4	419	}
1da177e4	420
404bdbfd PM	421	switch (*c) {
	422	case '-':
	423	add = 0;
	424	c++;
	425	break;
	426	case '+':
	427	c++;
	428	default:
	429	add = 1;
	430	break;
1da177e4	431	}
404bdbfd	432	addr = in_aton(c);
1da177e4	433
404bdbfd PM	434	spin_lock_bh(&recent_lock);
	435	e = recent_entry_lookup(t, addr, 0);
	436	if (e == NULL) {
	437	if (add)
	438	recent_entry_init(t, addr, 0);
	439	} else {
	440	if (add)
	441	recent_entry_update(t, e);
	442	else
	443	recent_entry_remove(t, e);
1da177e4	444	}
1da177e4	445	spin_unlock_bh(&recent_lock);
404bdbfd PM	446	return size;
404bdbfd PM	447	}
1da177e4	448
404bdbfd PM	449	static struct file_operations recent_fops = {
	450	.open = recent_seq_open,
	451	.read = seq_read,
	452	.write = recent_proc_write,
	453	.release = seq_release_private,
	454	.owner = THIS_MODULE,
	455	};
1da177e4	456	#endif /* CONFIG_PROC_FS */
1da177e4	457
1d5cd909 PM	458	static struct ipt_match recent_match = {
1d5cd909 PM	459	.name = "recent",
404bdbfd	460	.match = ipt_recent_match,
1d5cd909	461	.matchsize = sizeof(struct ipt_recent_info),
404bdbfd PM	462	.checkentry = ipt_recent_checkentry,
	463	.destroy = ipt_recent_destroy,
	464	.me = THIS_MODULE,
1da177e4 LT	465	};
1da177e4 LT	466
65b4b4e8	467	static int __init ipt_recent_init(void)
1da177e4	468	{
404bdbfd	469	int err;
1da177e4	470
404bdbfd PM	471	if (!ip_list_tot \|\| !ip_pkt_list_tot \|\| ip_pkt_list_tot > 255)
	472	return -EINVAL;
	473	ip_list_hash_size = 1 << fls(ip_list_tot);
1da177e4 LT	474
1da177e4 LT	475	err = ipt_register_match(&recent_match);
404bdbfd	476	#ifdef CONFIG_PROC_FS
1da177e4	477	if (err)
404bdbfd PM	478	return err;
	479	proc_dir = proc_mkdir("ipt_recent", proc_net);
	480	if (proc_dir == NULL) {
	481	ipt_unregister_match(&recent_match);
	482	err = -ENOMEM;
	483	}
	484	#endif
1da177e4 LT	485	return err;
	486	}
	487
404bdbfd	488	static void __exit ipt_recent_exit(void)
1da177e4	489	{
404bdbfd	490	BUG_ON(!list_empty(&tables));
1da177e4	491	ipt_unregister_match(&recent_match);
404bdbfd PM	492	#ifdef CONFIG_PROC_FS
	493	remove_proc_entry("ipt_recent", proc_net);
	494	#endif
1da177e4 LT	495	}
1da177e4 LT	496
65b4b4e8	497	module_init(ipt_recent_init);
404bdbfd	498	module_exit(ipt_recent_exit);