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/*
* Copyright (c) 2006 Patrick McHardy <kaber@trash.net>
* Copyright © CC Computer Consultants GmbH, 2007 - 2008
*
* 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
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/init.h>
#include <linux/ip.h>
#include <linux/ipv6.h>
#include <linux/module.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/slab.h>
#include <net/net_namespace.h>
#include <net/netns/generic.h>
#include <linux/netfilter/x_tables.h>
#include <linux/netfilter/xt_recent.h>
MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");
MODULE_AUTHOR("Jan Engelhardt <jengelh@medozas.de>");
MODULE_DESCRIPTION("Xtables: \"recently-seen\" host matching");
MODULE_LICENSE("GPL");
MODULE_ALIAS("ipt_recent");
MODULE_ALIAS("ip6t_recent");
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;
static unsigned int ip_list_uid = 0;
static unsigned int ip_list_gid = 0;
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_param(ip_list_uid, uint, S_IRUGO | S_IWUSR);
module_param(ip_list_gid, uint, S_IRUGO | S_IWUSR);
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 address 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/xt_recent/* files");
MODULE_PARM_DESC(ip_list_uid, "default owner of /proc/net/xt_recent/* files");
MODULE_PARM_DESC(ip_list_gid, "default owning group of /proc/net/xt_recent/* files");
struct recent_entry {
struct list_head list;
struct list_head lru_list;
union nf_inet_addr addr;
u_int16_t family;
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[XT_RECENT_NAME_LEN];
union nf_inet_addr mask;
unsigned int refcnt;
unsigned int entries;
struct list_head lru_list;
struct list_head iphash[0];
};
struct recent_net {
struct list_head tables;
#ifdef CONFIG_PROC_FS
struct proc_dir_entry *xt_recent;
#endif
};
static int recent_net_id;
static inline struct recent_net *recent_pernet(struct net *net)
{
return net_generic(net, recent_net_id);
}
static DEFINE_SPINLOCK(recent_lock);
static DEFINE_MUTEX(recent_mutex);
#ifdef CONFIG_PROC_FS
static const struct file_operations recent_old_fops, recent_mt_fops;
#endif
static u_int32_t hash_rnd __read_mostly;
static bool hash_rnd_inited __read_mostly;
static inline unsigned int recent_entry_hash4(const union nf_inet_addr *addr)
{
return jhash_1word((__force u32)addr->ip, hash_rnd) &
(ip_list_hash_size - 1);
}
static inline unsigned int recent_entry_hash6(const union nf_inet_addr *addr)
{
return jhash2((u32 *)addr->ip6, ARRAY_SIZE(addr->ip6), hash_rnd) &
(ip_list_hash_size - 1);
}
static struct recent_entry *
recent_entry_lookup(const struct recent_table *table,
const union nf_inet_addr *addrp, u_int16_t family,
u_int8_t ttl)
{
struct recent_entry *e;
unsigned int h;
if (family == NFPROTO_IPV4)
h = recent_entry_hash4(addrp);
else
h = recent_entry_hash6(addrp);
list_for_each_entry(e, &table->iphash[h], list)
if (e->family == family &&
memcmp(&e->addr, addrp, sizeof(e->addr)) == 0 &&
(ttl == e->ttl || ttl == 0 || e->ttl == 0))
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--;
}
/*
* Drop entries with timestamps older then 'time'.
*/
static void recent_entry_reap(struct recent_table *t, unsigned long time)
{
struct recent_entry *e;
/*
* The head of the LRU list is always the oldest entry.
*/
e = list_entry(t->lru_list.next, struct recent_entry, lru_list);
/*
* The last time stamp is the most recent.
*/
if (time_after(time, e->stamps[e->index-1]))
recent_entry_remove(t, e);
}
static struct recent_entry *
recent_entry_init(struct recent_table *t, const union nf_inet_addr *addr,
u_int16_t family, 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;
memcpy(&e->addr, addr, sizeof(e->addr));
e->ttl = ttl;
e->stamps[0] = jiffies;
e->nstamps = 1;
e->index = 1;
e->family = family;
if (family == NFPROTO_IPV4)
list_add_tail(&e->list,
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