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];
77 struct list_head lru_list;
78 struct list_head iphash[0];
81 static LIST_HEAD(tables);
82 static DEFINE_SPINLOCK(recent_lock);
83 static DEFINE_MUTEX(recent_mutex);
86 #ifdef CONFIG_NETFILTER_XT_MATCH_RECENT_PROC_COMPAT
87 static struct proc_dir_entry *proc_old_dir;
89 static struct proc_dir_entry *recent_proc_dir;
90 static const struct file_operations recent_old_fops, recent_mt_fops;
93 static u_int32_t hash_rnd __read_mostly;
94 static bool hash_rnd_inited __read_mostly;
96 static inline unsigned int recent_entry_hash4(const union nf_inet_addr *addr)
98 return jhash_1word((__force u32)addr->ip, hash_rnd) &
99 (ip_list_hash_size - 1);
102 static inline unsigned int recent_entry_hash6(const union nf_inet_addr *addr)
104 return jhash2((u32 *)addr->ip6, ARRAY_SIZE(addr->ip6), hash_rnd) &
105 (ip_list_hash_size - 1);
108 static struct recent_entry *
109 recent_entry_lookup(const struct recent_table *table,
110 const union nf_inet_addr *addrp, u_int16_t family,
113 struct recent_entry *e;
116 if (family == NFPROTO_IPV4)
117 h = recent_entry_hash4(addrp);
119 h = recent_entry_hash6(addrp);
121 list_for_each_entry(e, &table->iphash[h], list)
122 if (e->family == family &&
123 memcmp(&e->addr, addrp, sizeof(e->addr)) == 0 &&
124 (ttl == e->ttl || ttl == 0 || e->ttl == 0))
129 static void recent_entry_remove(struct recent_table *t, struct recent_entry *e)
132 list_del(&e->lru_list);
137 static struct recent_entry *
138 recent_entry_init(struct recent_table *t, const union nf_inet_addr *addr,
139 u_int16_t family, u_int8_t ttl)
141 struct recent_entry *e;
143 if (t->entries >= ip_list_tot) {
144 e = list_entry(t->lru_list.next, struct recent_entry, lru_list);
145 recent_entry_remove(t, e);
147 e = kmalloc(sizeof(*e) + sizeof(e->stamps[0]) * ip_pkt_list_tot,
151 memcpy(&e->addr, addr, sizeof(e->addr));
153 e->stamps[0] = jiffies;
157 if (family == NFPROTO_IPV4)
158 list_add_tail(&e->list, &t->iphash[recent_entry_hash4(addr)]);
160 list_add_tail(&e->list, &t->iphash[recent_entry_hash6(addr)]);
161 list_add_tail(&e->lru_list, &t->lru_list);
166 static void recent_entry_update(struct recent_table *t, struct recent_entry *e)
168 e->stamps[e->index++] = jiffies;
169 if (e->index > e->nstamps)
170 e->nstamps = e->index;
171 e->index %= ip_pkt_list_tot;
172 list_move_tail(&e->lru_list, &t->lru_list);
175 static struct recent_table *recent_table_lookup(const char *name)
177 struct recent_table *t;
179 list_for_each_entry(t, &tables, list)
180 if (!strcmp(t->name, name))
185 static void recent_table_flush(struct recent_table *t)
187 struct recent_entry *e, *next;
190 for (i = 0; i < ip_list_hash_size; i++)
191 list_for_each_entry_safe(e, next, &t->iphash[i], list)
192 recent_entry_remove(t, e);
196 recent_mt(const struct sk_buff *skb, const struct xt_match_param *par)
198 const struct xt_recent_mtinfo *info = par->matchinfo;
199 struct recent_table *t;
200 struct recent_entry *e;
201 union nf_inet_addr addr = {};
203 bool ret = info->invert;
205 if (par->match->family == NFPROTO_IPV4) {
206 const struct iphdr *iph = ip_hdr(skb);
208 if (info->side == XT_RECENT_DEST)
209 addr.ip = iph->daddr;
211 addr.ip = iph->saddr;
215 const struct ipv6hdr *iph = ipv6_hdr(skb);
217 if (info->side == XT_RECENT_DEST)
218 memcpy(&addr.in6, &iph->daddr, sizeof(addr.in6));
220 memcpy(&addr.in6, &iph->saddr, sizeof(addr.in6));
222 ttl = iph->hop_limit;
225 /* use TTL as seen before forwarding */
226 if (par->out != NULL && skb->sk == NULL)
229 spin_lock_bh(&recent_lock);
230 t = recent_table_lookup(info->name);
231 e = recent_entry_lookup(t, &addr, par->match->family,
232 (info->check_set & XT_RECENT_TTL) ? ttl : 0);
234 if (!(info->check_set & XT_RECENT_SET))
236 e = recent_entry_init(t, &addr, par->match->family, ttl);
238 *par->hotdrop = true;
243 if (info->check_set & XT_RECENT_SET)
245 else if (info->check_set & XT_RECENT_REMOVE) {
246 recent_entry_remove(t, e);
248 } else if (info->check_set & (XT_RECENT_CHECK | XT_RECENT_UPDATE)) {
249 unsigned long time = jiffies - info->seconds * HZ;
250 unsigned int i, hits = 0;
252 for (i = 0; i < e->nstamps; i++) {
253 if (info->seconds && time_after(time, e->stamps[i]))
255 if (++hits >= info->hit_count) {
262 if (info->check_set & XT_RECENT_SET ||
263 (info->check_set & XT_RECENT_UPDATE && ret)) {
264 recent_entry_update(t, e);
268 spin_unlock_bh(&recent_lock);
272 static bool recent_mt_check(const struct xt_mtchk_param *par)
274 const struct xt_recent_mtinfo *info = par->matchinfo;
275 struct recent_table *t;
276 #ifdef CONFIG_PROC_FS
277 struct proc_dir_entry *pde;
282 if (unlikely(!hash_rnd_inited)) {
283 get_random_bytes(&hash_rnd, sizeof(hash_rnd));
284 hash_rnd_inited = true;
286 if (hweight8(info->check_set &
287 (XT_RECENT_SET | XT_RECENT_REMOVE |
288 XT_RECENT_CHECK | XT_RECENT_UPDATE)) != 1)
290 if ((info->check_set & (XT_RECENT_SET | XT_RECENT_REMOVE)) &&
291 (info->seconds || info->hit_count))
293 if (info->hit_count > ip_pkt_list_tot)
295 if (info->name[0] == '\0' ||
296 strnlen(info->name, XT_RECENT_NAME_LEN) == XT_RECENT_NAME_LEN)
299 mutex_lock(&recent_mutex);
300 t = recent_table_lookup(info->name);
307 t = kzalloc(sizeof(*t) + sizeof(t->iphash[0]) * ip_list_hash_size,
312 strcpy(t->name, info->name);
313 INIT_LIST_HEAD(&t->lru_list);
314 for (i = 0; i < ip_list_hash_size; i++)
315 INIT_LIST_HEAD(&t->iphash[i]);
316 #ifdef CONFIG_PROC_FS
317 pde = proc_create_data(t->name, ip_list_perms, recent_proc_dir,
323 pde->uid = ip_list_uid;
324 pde->gid = ip_list_gid;
325 #ifdef CONFIG_NETFILTER_XT_MATCH_RECENT_PROC_COMPAT
326 pde = proc_create_data(t->name, ip_list_perms, proc_old_dir,
327 &recent_old_fops, t);
329 remove_proc_entry(t->name, proc_old_dir);
333 pde->uid = ip_list_uid;
334 pde->gid = ip_list_gid;
337 spin_lock_bh(&recent_lock);
338 list_add_tail(&t->list, &tables);
339 spin_unlock_bh(&recent_lock);
342 mutex_unlock(&recent_mutex);
346 static void recent_mt_destroy(const struct xt_mtdtor_param *par)
348 const struct xt_recent_mtinfo *info = par->matchinfo;
349 struct recent_table *t;
351 mutex_lock(&recent_mutex);
352 t = recent_table_lookup(info->name);
353 if (--t->refcnt == 0) {
354 spin_lock_bh(&recent_lock);
356 spin_unlock_bh(&recent_lock);
357 #ifdef CONFIG_PROC_FS
358 #ifdef CONFIG_NETFILTER_XT_MATCH_RECENT_PROC_COMPAT
359 remove_proc_entry(t->name, proc_old_dir);
361 remove_proc_entry(t->name, recent_proc_dir);
363 recent_table_flush(t);
366 mutex_unlock(&recent_mutex);
369 #ifdef CONFIG_PROC_FS
370 struct recent_iter_state {
371 const struct recent_table *table;
375 static void *recent_seq_start(struct seq_file *seq, loff_t *pos)
376 __acquires(recent_lock)
378 struct recent_iter_state *st = seq->private;
379 const struct recent_table *t = st->table;
380 struct recent_entry *e;
383 spin_lock_bh(&recent_lock);
385 for (st->bucket = 0; st->bucket < ip_list_hash_size; st->bucket++)
386 list_for_each_entry(e, &t->iphash[st->bucket], list)
392 static void *recent_seq_next(struct seq_file *seq, void *v, loff_t *pos)
394 struct recent_iter_state *st = seq->private;
395 const struct recent_table *t = st->table;
396 const struct recent_entry *e = v;
397 const struct list_head *head = e->list.next;
399 while (head == &t->iphash[st->bucket]) {
400 if (++st->bucket >= ip_list_hash_size)
402 head = t->iphash[st->bucket].next;
405 return list_entry(head, struct recent_entry, list);
408 static void recent_seq_stop(struct seq_file *s, void *v)
409 __releases(recent_lock)
411 spin_unlock_bh(&recent_lock);
414 static int recent_seq_show(struct seq_file *seq, void *v)
416 const struct recent_entry *e = v;
419 i = (e->index - 1) % ip_pkt_list_tot;
420 if (e->family == NFPROTO_IPV4)
421 seq_printf(seq, "src=%pI4 ttl: %u last_seen: %lu oldest_pkt: %u",
422 &e->addr.ip, e->ttl, e->stamps[i], e->index);
424 seq_printf(seq, "src=%pI6 ttl: %u last_seen: %lu oldest_pkt: %u",
425 &e->addr.in6, e->ttl, e->stamps[i], e->index);
426 for (i = 0; i < e->nstamps; i++)
427 seq_printf(seq, "%s %lu", i ? "," : "", e->stamps[i]);
428 seq_printf(seq, "\n");
432 static const struct seq_operations recent_seq_ops = {
433 .start = recent_seq_start,
434 .next = recent_seq_next,
435 .stop = recent_seq_stop,
436 .show = recent_seq_show,
439 static int recent_seq_open(struct inode *inode, struct file *file)
441 struct proc_dir_entry *pde = PDE(inode);
442 struct recent_iter_state *st;
444 st = __seq_open_private(file, &recent_seq_ops, sizeof(*st));
448 st->table = pde->data;
452 #ifdef CONFIG_NETFILTER_XT_MATCH_RECENT_PROC_COMPAT
453 static int recent_old_seq_open(struct inode *inode, struct file *filp)
455 static bool warned_of_old;
457 if (unlikely(!warned_of_old)) {
458 printk(KERN_INFO KBUILD_MODNAME ": Use of /proc/net/ipt_recent"
459 " is deprecated; use /proc/net/xt_recent.\n");
460 warned_of_old = true;
462 return recent_seq_open(inode, filp);
465 static ssize_t recent_old_proc_write(struct file *file,
466 const char __user *input,
467 size_t size, loff_t *loff)
469 const struct proc_dir_entry *pde = PDE(file->f_path.dentry->d_inode);
470 struct recent_table *t = pde->data;
471 struct recent_entry *e;
472 char buf[sizeof("+255.255.255.255")], *c = buf;
473 union nf_inet_addr addr = {};
476 if (size > sizeof(buf))
478 if (copy_from_user(buf, input, size))
483 if (size - (c - buf) < 5)
485 if (!strncmp(c, "clear", 5)) {
487 spin_lock_bh(&recent_lock);
488 recent_table_flush(t);
489 spin_unlock_bh(&recent_lock);
504 addr.ip = in_aton(c);
506 spin_lock_bh(&recent_lock);
507 e = recent_entry_lookup(t, &addr, NFPROTO_IPV4, 0);
510 recent_entry_init(t, &addr, NFPROTO_IPV4, 0);
513 recent_entry_update(t, e);
515 recent_entry_remove(t, e);
517 spin_unlock_bh(&recent_lock);
521 static const struct file_operations recent_old_fops = {
522 .open = recent_old_seq_open,
524 .write = recent_old_proc_write,
525 .release = seq_release_private,
526 .owner = THIS_MODULE,
531 recent_mt_proc_write(struct file *file, const char __user *input,
532 size_t size, loff_t *loff)
534 const struct proc_dir_entry *pde = PDE(file->f_path.dentry->d_inode);
535 struct recent_table *t = pde->data;
536 struct recent_entry *e;
537 char buf[sizeof("+b335:1d35:1e55:dead:c0de:1715:5afe:c0de")];
539 union nf_inet_addr addr = {};
545 if (size > sizeof(buf))
547 if (copy_from_user(buf, input, size) != 0)
550 /* Strict protocol! */
554 case '/': /* flush table */
555 spin_lock_bh(&recent_lock);
556 recent_table_flush(t);
557 spin_unlock_bh(&recent_lock);
559 case '-': /* remove address */
562 case '+': /* add address */
566 printk(KERN_INFO KBUILD_MODNAME ": Need +ip, -ip or /\n");
572 if (strnchr(c, size, ':') != NULL) {
573 family = NFPROTO_IPV6;
574 succ = in6_pton(c, size, (void *)&addr, '\n', NULL);
576 family = NFPROTO_IPV4;
577 succ = in4_pton(c, size, (void *)&addr, '\n', NULL);
581 printk(KERN_INFO KBUILD_MODNAME ": illegal address written "
586 spin_lock_bh(&recent_lock);
587 e = recent_entry_lookup(t, &addr, family, 0);
590 recent_entry_init(t, &addr, family, 0);
593 recent_entry_update(t, e);
595 recent_entry_remove(t, e);
597 spin_unlock_bh(&recent_lock);
598 /* Note we removed one above */
603 static const struct file_operations recent_mt_fops = {
604 .open = recent_seq_open,
606 .write = recent_mt_proc_write,
607 .release = seq_release_private,
608 .owner = THIS_MODULE,
610 #endif /* CONFIG_PROC_FS */
612 static struct xt_match recent_mt_reg[] __read_mostly = {
616 .family = NFPROTO_IPV4,
618 .matchsize = sizeof(struct xt_recent_mtinfo),
619 .checkentry = recent_mt_check,
620 .destroy = recent_mt_destroy,
626 .family = NFPROTO_IPV6,
628 .matchsize = sizeof(struct xt_recent_mtinfo),
629 .checkentry = recent_mt_check,
630 .destroy = recent_mt_destroy,
635 static int __init recent_mt_init(void)
639 if (!ip_list_tot || !ip_pkt_list_tot || ip_pkt_list_tot > 255)
641 ip_list_hash_size = 1 << fls(ip_list_tot);
643 err = xt_register_matches(recent_mt_reg, ARRAY_SIZE(recent_mt_reg));
644 #ifdef CONFIG_PROC_FS
647 recent_proc_dir = proc_mkdir("xt_recent", init_net.proc_net);
648 if (recent_proc_dir == NULL) {
649 xt_unregister_matches(recent_mt_reg, ARRAY_SIZE(recent_mt_reg));
652 #ifdef CONFIG_NETFILTER_XT_MATCH_RECENT_PROC_COMPAT
655 proc_old_dir = proc_mkdir("ipt_recent", init_net.proc_net);
656 if (proc_old_dir == NULL) {
657 remove_proc_entry("xt_recent", init_net.proc_net);
658 xt_unregister_matches(recent_mt_reg, ARRAY_SIZE(recent_mt_reg));
666 static void __exit recent_mt_exit(void)
668 BUG_ON(!list_empty(&tables));
669 xt_unregister_matches(recent_mt_reg, ARRAY_SIZE(recent_mt_reg));
670 #ifdef CONFIG_PROC_FS
671 #ifdef CONFIG_NETFILTER_XT_MATCH_RECENT_PROC_COMPAT
672 remove_proc_entry("ipt_recent", init_net.proc_net);
674 remove_proc_entry("xt_recent", init_net.proc_net);
678 module_init(recent_mt_init);
679 module_exit(recent_mt_exit);