2 * Copyright (c) 2006 Patrick McHardy <kaber@trash.net>
3 * Copyright © CC Computer Consultants GmbH, 2007 - 2008
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License version 2 as
7 * published by the Free Software Foundation.
9 * This is a replacement of the old ipt_recent module, which carried the
10 * following copyright notice:
12 * Author: Stephen Frost <sfrost@snowman.net>
13 * Copyright 2002-2003, Stephen Frost, 2.5.x port by laforge@netfilter.org
15 #include <linux/init.h>
17 #include <linux/ipv6.h>
18 #include <linux/module.h>
19 #include <linux/moduleparam.h>
20 #include <linux/proc_fs.h>
21 #include <linux/seq_file.h>
22 #include <linux/string.h>
23 #include <linux/ctype.h>
24 #include <linux/list.h>
25 #include <linux/random.h>
26 #include <linux/jhash.h>
27 #include <linux/bitops.h>
28 #include <linux/skbuff.h>
29 #include <linux/inet.h>
30 #include <net/net_namespace.h>
32 #include <linux/netfilter/x_tables.h>
33 #include <linux/netfilter/xt_recent.h>
35 MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");
36 MODULE_AUTHOR("Jan Engelhardt <jengelh@computergmbh.de>");
37 MODULE_DESCRIPTION("Xtables: \"recently-seen\" host matching for IPv4");
38 MODULE_LICENSE("GPL");
39 MODULE_ALIAS("ipt_recent");
40 MODULE_ALIAS("ip6t_recent");
42 static unsigned int ip_list_tot
= 100;
43 static unsigned int ip_pkt_list_tot
= 20;
44 static unsigned int ip_list_hash_size
= 0;
45 static unsigned int ip_list_perms
= 0644;
46 static unsigned int ip_list_uid
= 0;
47 static unsigned int ip_list_gid
= 0;
48 module_param(ip_list_tot
, uint
, 0400);
49 module_param(ip_pkt_list_tot
, uint
, 0400);
50 module_param(ip_list_hash_size
, uint
, 0400);
51 module_param(ip_list_perms
, uint
, 0400);
52 module_param(ip_list_uid
, uint
, 0400);
53 module_param(ip_list_gid
, uint
, 0400);
54 MODULE_PARM_DESC(ip_list_tot
, "number of IPs to remember per list");
55 MODULE_PARM_DESC(ip_pkt_list_tot
, "number of packets per IP to remember (max. 255)");
56 MODULE_PARM_DESC(ip_list_hash_size
, "size of hash table used to look up IPs");
57 MODULE_PARM_DESC(ip_list_perms
, "permissions on /proc/net/xt_recent/* files");
58 MODULE_PARM_DESC(ip_list_uid
,"owner of /proc/net/xt_recent/* files");
59 MODULE_PARM_DESC(ip_list_gid
,"owning group of /proc/net/xt_recent/* files");
62 struct list_head list
;
63 struct list_head lru_list
;
64 union nf_inet_addr addr
;
69 unsigned long stamps
[0];
73 struct list_head list
;
74 char name
[XT_RECENT_NAME_LEN
];
76 struct proc_dir_entry
*proc_old
, *proc
;
80 struct list_head lru_list
;
81 struct list_head iphash
[0];
84 static LIST_HEAD(tables
);
85 static DEFINE_SPINLOCK(recent_lock
);
86 static DEFINE_MUTEX(recent_mutex
);
89 #ifdef CONFIG_NETFILTER_XT_MATCH_RECENT_PROC_COMPAT
90 static struct proc_dir_entry
*proc_old_dir
;
92 static struct proc_dir_entry
*recent_proc_dir
;
93 static const struct file_operations recent_old_fops
, recent_mt_fops
;
96 static u_int32_t hash_rnd
;
97 static bool hash_rnd_initted
;
99 static unsigned int recent_entry_hash4(const union nf_inet_addr
*addr
)
101 if (!hash_rnd_initted
) {
102 get_random_bytes(&hash_rnd
, sizeof(hash_rnd
));
103 hash_rnd_initted
= true;
105 return jhash_1word((__force u32
)addr
->ip
, hash_rnd
) &
106 (ip_list_hash_size
- 1);
109 static unsigned int recent_entry_hash6(const union nf_inet_addr
*addr
)
111 if (!hash_rnd_initted
) {
112 get_random_bytes(&hash_rnd
, sizeof(hash_rnd
));
113 hash_rnd_initted
= true;
115 return jhash2((u32
*)addr
->ip6
, ARRAY_SIZE(addr
->ip6
), hash_rnd
) &
116 (ip_list_hash_size
- 1);
119 static struct recent_entry
*
120 recent_entry_lookup(const struct recent_table
*table
,
121 const union nf_inet_addr
*addrp
, u_int16_t family
,
124 struct recent_entry
*e
;
127 if (family
== NFPROTO_IPV4
)
128 h
= recent_entry_hash4(addrp
);
130 h
= recent_entry_hash6(addrp
);
132 list_for_each_entry(e
, &table
->iphash
[h
], list
)
133 if (e
->family
== family
&&
134 memcmp(&e
->addr
, addrp
, sizeof(e
->addr
)) == 0 &&
135 (ttl
== e
->ttl
|| ttl
== 0 || e
->ttl
== 0))
140 static void recent_entry_remove(struct recent_table
*t
, struct recent_entry
*e
)
143 list_del(&e
->lru_list
);
148 static struct recent_entry
*
149 recent_entry_init(struct recent_table
*t
, const union nf_inet_addr
*addr
,
150 u_int16_t family
, u_int8_t ttl
)
152 struct recent_entry
*e
;
154 if (t
->entries
>= ip_list_tot
) {
155 e
= list_entry(t
->lru_list
.next
, struct recent_entry
, lru_list
);
156 recent_entry_remove(t
, e
);
158 e
= kmalloc(sizeof(*e
) + sizeof(e
->stamps
[0]) * ip_pkt_list_tot
,
162 memcpy(&e
->addr
, addr
, sizeof(e
->addr
));
164 e
->stamps
[0] = jiffies
;
168 if (family
== NFPROTO_IPV4
)
169 list_add_tail(&e
->list
, &t
->iphash
[recent_entry_hash4(addr
)]);
171 list_add_tail(&e
->list
, &t
->iphash
[recent_entry_hash6(addr
)]);
172 list_add_tail(&e
->lru_list
, &t
->lru_list
);
177 static void recent_entry_update(struct recent_table
*t
, struct recent_entry
*e
)
179 e
->stamps
[e
->index
++] = jiffies
;
180 if (e
->index
> e
->nstamps
)
181 e
->nstamps
= e
->index
;
182 e
->index
%= ip_pkt_list_tot
;
183 list_move_tail(&e
->lru_list
, &t
->lru_list
);
186 static struct recent_table
*recent_table_lookup(const char *name
)
188 struct recent_table
*t
;
190 list_for_each_entry(t
, &tables
, list
)
191 if (!strcmp(t
->name
, name
))
196 static void recent_table_flush(struct recent_table
*t
)
198 struct recent_entry
*e
, *next
;
201 for (i
= 0; i
< ip_list_hash_size
; i
++)
202 list_for_each_entry_safe(e
, next
, &t
->iphash
[i
], list
)
203 recent_entry_remove(t
, e
);
207 recent_mt(const struct sk_buff
*skb
, const struct xt_match_param
*par
)
209 const struct xt_recent_mtinfo
*info
= par
->matchinfo
;
210 struct recent_table
*t
;
211 struct recent_entry
*e
;
212 union nf_inet_addr addr
= {};
214 bool ret
= info
->invert
;
216 if (par
->match
->family
== NFPROTO_IPV4
) {
217 const struct iphdr
*iph
= ip_hdr(skb
);
219 if (info
->side
== XT_RECENT_DEST
)
220 addr
.ip
= iph
->daddr
;
222 addr
.ip
= iph
->saddr
;
226 const struct ipv6hdr
*iph
= ipv6_hdr(skb
);
228 if (info
->side
== XT_RECENT_DEST
)
229 memcpy(&addr
.in6
, &iph
->daddr
, sizeof(addr
.in6
));
231 memcpy(&addr
.in6
, &iph
->saddr
, sizeof(addr
.in6
));
233 ttl
= iph
->hop_limit
;
236 /* use TTL as seen before forwarding */
237 if (par
->out
!= NULL
&& skb
->sk
== NULL
)
240 spin_lock_bh(&recent_lock
);
241 t
= recent_table_lookup(info
->name
);
242 e
= recent_entry_lookup(t
, &addr
, par
->match
->family
,
243 (info
->check_set
& XT_RECENT_TTL
) ? ttl
: 0);
245 if (!(info
->check_set
& XT_RECENT_SET
))
247 e
= recent_entry_init(t
, &addr
, par
->match
->family
, ttl
);
249 *par
->hotdrop
= true;
254 if (info
->check_set
& XT_RECENT_SET
)
256 else if (info
->check_set
& XT_RECENT_REMOVE
) {
257 recent_entry_remove(t
, e
);
259 } else if (info
->check_set
& (XT_RECENT_CHECK
| XT_RECENT_UPDATE
)) {
260 unsigned long time
= jiffies
- info
->seconds
* HZ
;
261 unsigned int i
, hits
= 0;
263 for (i
= 0; i
< e
->nstamps
; i
++) {
264 if (info
->seconds
&& time_after(time
, e
->stamps
[i
]))
266 if (++hits
>= info
->hit_count
) {
273 if (info
->check_set
& XT_RECENT_SET
||
274 (info
->check_set
& XT_RECENT_UPDATE
&& ret
)) {
275 recent_entry_update(t
, e
);
279 spin_unlock_bh(&recent_lock
);
283 static bool recent_mt_check(const struct xt_mtchk_param
*par
)
285 const struct xt_recent_mtinfo
*info
= par
->matchinfo
;
286 struct recent_table
*t
;
290 if (hweight8(info
->check_set
&
291 (XT_RECENT_SET
| XT_RECENT_REMOVE
|
292 XT_RECENT_CHECK
| XT_RECENT_UPDATE
)) != 1)
294 if ((info
->check_set
& (XT_RECENT_SET
| XT_RECENT_REMOVE
)) &&
295 (info
->seconds
|| info
->hit_count
))
297 if (info
->hit_count
> ip_pkt_list_tot
)
299 if (info
->name
[0] == '\0' ||
300 strnlen(info
->name
, XT_RECENT_NAME_LEN
) == XT_RECENT_NAME_LEN
)
303 mutex_lock(&recent_mutex
);
304 t
= recent_table_lookup(info
->name
);
311 t
= kzalloc(sizeof(*t
) + sizeof(t
->iphash
[0]) * ip_list_hash_size
,
316 strcpy(t
->name
, info
->name
);
317 INIT_LIST_HEAD(&t
->lru_list
);
318 for (i
= 0; i
< ip_list_hash_size
; i
++)
319 INIT_LIST_HEAD(&t
->iphash
[i
]);
320 #ifdef CONFIG_PROC_FS
321 t
->proc
= proc_create(t
->name
, ip_list_perms
, recent_proc_dir
,
323 if (t
->proc
== NULL
) {
327 #ifdef CONFIG_NETFILTER_XT_MATCH_RECENT_PROC_COMPAT
328 t
->proc_old
= proc_create(t
->name
, ip_list_perms
, proc_old_dir
,
330 if (t
->proc_old
== NULL
) {
331 remove_proc_entry(t
->name
, proc_old_dir
);
335 t
->proc_old
->uid
= ip_list_uid
;
336 t
->proc_old
->gid
= ip_list_gid
;
337 t
->proc_old
->data
= t
;
339 t
->proc
->uid
= ip_list_uid
;
340 t
->proc
->gid
= ip_list_gid
;
343 spin_lock_bh(&recent_lock
);
344 list_add_tail(&t
->list
, &tables
);
345 spin_unlock_bh(&recent_lock
);
348 mutex_unlock(&recent_mutex
);
352 static void recent_mt_destroy(const struct xt_mtdtor_param
*par
)
354 const struct xt_recent_mtinfo
*info
= par
->matchinfo
;
355 struct recent_table
*t
;
357 mutex_lock(&recent_mutex
);
358 t
= recent_table_lookup(info
->name
);
359 if (--t
->refcnt
== 0) {
360 spin_lock_bh(&recent_lock
);
362 spin_unlock_bh(&recent_lock
);
363 #ifdef CONFIG_PROC_FS
364 #ifdef CONFIG_NETFILTER_XT_MATCH_RECENT_PROC_COMPAT
365 remove_proc_entry(t
->name
, proc_old_dir
);
367 remove_proc_entry(t
->name
, recent_proc_dir
);
369 recent_table_flush(t
);
372 mutex_unlock(&recent_mutex
);
375 #ifdef CONFIG_PROC_FS
376 struct recent_iter_state
{
377 const struct recent_table
*table
;
381 static void *recent_seq_start(struct seq_file
*seq
, loff_t
*pos
)
382 __acquires(recent_lock
)
384 struct recent_iter_state
*st
= seq
->private;
385 const struct recent_table
*t
= st
->table
;
386 struct recent_entry
*e
;
389 spin_lock_bh(&recent_lock
);
391 for (st
->bucket
= 0; st
->bucket
< ip_list_hash_size
; st
->bucket
++)
392 list_for_each_entry(e
, &t
->iphash
[st
->bucket
], list
)
398 static void *recent_seq_next(struct seq_file
*seq
, void *v
, loff_t
*pos
)
400 struct recent_iter_state
*st
= seq
->private;
401 const struct recent_table
*t
= st
->table
;
402 const struct recent_entry
*e
= v
;
403 const struct list_head
*head
= e
->list
.next
;
405 while (head
== &t
->iphash
[st
->bucket
]) {
406 if (++st
->bucket
>= ip_list_hash_size
)
408 head
= t
->iphash
[st
->bucket
].next
;
411 return list_entry(head
, struct recent_entry
, list
);
414 static void recent_seq_stop(struct seq_file
*s
, void *v
)
415 __releases(recent_lock
)
417 spin_unlock_bh(&recent_lock
);
420 static int recent_seq_show(struct seq_file
*seq
, void *v
)
422 const struct recent_entry
*e
= v
;
425 i
= (e
->index
- 1) % ip_pkt_list_tot
;
426 if (e
->family
== NFPROTO_IPV4
)
427 seq_printf(seq
, "src=" NIPQUAD_FMT
" ttl: %u last_seen: %lu "
428 "oldest_pkt: %u", NIPQUAD(e
->addr
.ip
), e
->ttl
,
429 e
->stamps
[i
], e
->index
);
431 seq_printf(seq
, "src=" NIP6_FMT
" ttl: %u last_seen: %lu "
432 "oldest_pkt: %u", NIP6(e
->addr
.in6
), e
->ttl
,
433 e
->stamps
[i
], e
->index
);
434 for (i
= 0; i
< e
->nstamps
; i
++)
435 seq_printf(seq
, "%s %lu", i
? "," : "", e
->stamps
[i
]);
436 seq_printf(seq
, "\n");
440 static const struct seq_operations recent_seq_ops
= {
441 .start
= recent_seq_start
,
442 .next
= recent_seq_next
,
443 .stop
= recent_seq_stop
,
444 .show
= recent_seq_show
,
447 static int recent_seq_open(struct inode
*inode
, struct file
*file
)
449 struct proc_dir_entry
*pde
= PDE(inode
);
450 struct recent_iter_state
*st
;
452 st
= __seq_open_private(file
, &recent_seq_ops
, sizeof(*st
));
456 st
->table
= pde
->data
;
460 #ifdef CONFIG_NETFILTER_XT_MATCH_RECENT_PROC_COMPAT
461 static int recent_old_seq_open(struct inode
*inode
, struct file
*filp
)
463 static bool warned_of_old
;
465 if (unlikely(!warned_of_old
)) {
466 printk(KERN_INFO KBUILD_MODNAME
": Use of /proc/net/ipt_recent"
467 " is deprecated; use /proc/net/xt_recent.\n");
468 warned_of_old
= true;
470 return recent_seq_open(inode
, filp
);
473 static ssize_t
recent_old_proc_write(struct file
*file
,
474 const char __user
*input
,
475 size_t size
, loff_t
*loff
)
477 const struct proc_dir_entry
*pde
= PDE(file
->f_path
.dentry
->d_inode
);
478 struct recent_table
*t
= pde
->data
;
479 struct recent_entry
*e
;
480 char buf
[sizeof("+255.255.255.255")], *c
= buf
;
484 if (size
> sizeof(buf
))
486 if (copy_from_user(buf
, input
, size
))
492 if (size
- (c
- buf
) < 5)
494 if (!strncmp(c
, "clear", 5)) {
496 spin_lock_bh(&recent_lock
);
497 recent_table_flush(t
);
498 spin_unlock_bh(&recent_lock
);
515 spin_lock_bh(&recent_lock
);
516 e
= recent_entry_lookup(t
, (const void *)&addr
, NFPROTO_IPV4
, 0);
519 recent_entry_init(t
, (const void *)&addr
,
523 recent_entry_update(t
, e
);
525 recent_entry_remove(t
, e
);
527 spin_unlock_bh(&recent_lock
);
531 static const struct file_operations recent_old_fops
= {
532 .open
= recent_old_seq_open
,
534 .write
= recent_old_proc_write
,
535 .release
= seq_release_private
,
536 .owner
= THIS_MODULE
,
541 recent_mt_proc_write(struct file
*file
, const char __user
*input
,
542 size_t size
, loff_t
*loff
)
544 const struct proc_dir_entry
*pde
= PDE(file
->f_path
.dentry
->d_inode
);
545 struct recent_table
*t
= pde
->data
;
546 struct recent_entry
*e
;
547 char buf
[sizeof("+b335:1d35:1e55:dead:c0de:1715:5afe:c0de")];
549 union nf_inet_addr addr
;
555 if (size
> sizeof(buf
))
557 if (copy_from_user(buf
, input
, size
) != 0)
560 /* Strict protocol! */
564 case '/': /* flush table */
565 spin_lock_bh(&recent_lock
);
566 recent_table_flush(t
);
567 spin_unlock_bh(&recent_lock
);
569 case '-': /* remove address */
572 case '+': /* add address */
576 printk(KERN_INFO KBUILD_MODNAME
": Need +ip, -ip or /\n");
582 if (strnchr(c
, size
, ':') != NULL
) {
583 family
= NFPROTO_IPV6
;
584 succ
= in6_pton(c
, size
, (void *)&addr
, '\n', NULL
);
586 family
= NFPROTO_IPV4
;
587 succ
= in4_pton(c
, size
, (void *)&addr
, '\n', NULL
);
591 printk(KERN_INFO KBUILD_MODNAME
": illegal address written "
596 spin_lock_bh(&recent_lock
);
597 e
= recent_entry_lookup(t
, &addr
, family
, 0);
600 recent_entry_init(t
, &addr
, family
, 0);
603 recent_entry_update(t
, e
);
605 recent_entry_remove(t
, e
);
607 spin_unlock_bh(&recent_lock
);
608 /* Note we removed one above */
613 static const struct file_operations recent_mt_fops
= {
614 .open
= recent_seq_open
,
616 .write
= recent_mt_proc_write
,
617 .release
= seq_release_private
,
618 .owner
= THIS_MODULE
,
620 #endif /* CONFIG_PROC_FS */
622 static struct xt_match recent_mt_reg
[] __read_mostly
= {
626 .family
= NFPROTO_IPV4
,
628 .matchsize
= sizeof(struct xt_recent_mtinfo
),
629 .checkentry
= recent_mt_check
,
630 .destroy
= recent_mt_destroy
,
636 .family
= NFPROTO_IPV6
,
638 .matchsize
= sizeof(struct xt_recent_mtinfo
),
639 .checkentry
= recent_mt_check
,
640 .destroy
= recent_mt_destroy
,
645 static int __init
recent_mt_init(void)
649 if (!ip_list_tot
|| !ip_pkt_list_tot
|| ip_pkt_list_tot
> 255)
651 ip_list_hash_size
= 1 << fls(ip_list_tot
);
653 err
= xt_register_matches(recent_mt_reg
, ARRAY_SIZE(recent_mt_reg
));
654 #ifdef CONFIG_PROC_FS
657 recent_proc_dir
= proc_mkdir("xt_recent", init_net
.proc_net
);
658 if (recent_proc_dir
== NULL
) {
659 xt_unregister_matches(recent_mt_reg
, ARRAY_SIZE(recent_mt_reg
));
662 #ifdef CONFIG_NETFILTER_XT_MATCH_RECENT_PROC_COMPAT
665 proc_old_dir
= proc_mkdir("ipt_recent", init_net
.proc_net
);
666 if (proc_old_dir
== NULL
) {
667 remove_proc_entry("xt_recent", init_net
.proc_net
);
668 xt_unregister_matches(recent_mt_reg
, ARRAY_SIZE(recent_mt_reg
));
676 static void __exit
recent_mt_exit(void)
678 BUG_ON(!list_empty(&tables
));
679 xt_unregister_matches(recent_mt_reg
, ARRAY_SIZE(recent_mt_reg
));
680 #ifdef CONFIG_PROC_FS
681 #ifdef CONFIG_NETFILTER_XT_MATCH_RECENT_PROC_COMPAT
682 remove_proc_entry("ipt_recent", init_net
.proc_net
);
684 remove_proc_entry("xt_recent", init_net
.proc_net
);
688 module_init(recent_mt_init
);
689 module_exit(recent_mt_exit
);