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>
31 #include <net/netns/generic.h>
33 #include <linux/netfilter/x_tables.h>
34 #include <linux/netfilter/xt_recent.h>
36 MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");
37 MODULE_AUTHOR("Jan Engelhardt <jengelh@computergmbh.de>");
38 MODULE_DESCRIPTION("Xtables: \"recently-seen\" host matching for IPv4");
39 MODULE_LICENSE("GPL");
40 MODULE_ALIAS("ipt_recent");
41 MODULE_ALIAS("ip6t_recent");
43 static unsigned int ip_list_tot = 100;
44 static unsigned int ip_pkt_list_tot = 20;
45 static unsigned int ip_list_hash_size = 0;
46 static unsigned int ip_list_perms = 0644;
47 static unsigned int ip_list_uid = 0;
48 static unsigned int ip_list_gid = 0;
49 module_param(ip_list_tot, uint, 0400);
50 module_param(ip_pkt_list_tot, uint, 0400);
51 module_param(ip_list_hash_size, uint, 0400);
52 module_param(ip_list_perms, uint, 0400);
53 module_param(ip_list_uid, uint, 0400);
54 module_param(ip_list_gid, uint, 0400);
55 MODULE_PARM_DESC(ip_list_tot, "number of IPs to remember per list");
56 MODULE_PARM_DESC(ip_pkt_list_tot, "number of packets per IP to remember (max. 255)");
57 MODULE_PARM_DESC(ip_list_hash_size, "size of hash table used to look up IPs");
58 MODULE_PARM_DESC(ip_list_perms, "permissions on /proc/net/xt_recent/* files");
59 MODULE_PARM_DESC(ip_list_uid,"owner of /proc/net/xt_recent/* files");
60 MODULE_PARM_DESC(ip_list_gid,"owning group of /proc/net/xt_recent/* files");
63 struct list_head list;
64 struct list_head lru_list;
65 union nf_inet_addr addr;
70 unsigned long stamps[0];
74 struct list_head list;
75 char name[XT_RECENT_NAME_LEN];
78 struct list_head lru_list;
79 struct list_head iphash[0];
83 struct list_head tables;
85 struct proc_dir_entry *xt_recent;
86 #ifdef CONFIG_NETFILTER_XT_MATCH_RECENT_PROC_COMPAT
87 struct proc_dir_entry *ipt_recent;
92 static int recent_net_id;
93 static inline struct recent_net *recent_pernet(struct net *net)
95 return net_generic(net, recent_net_id);
98 static DEFINE_SPINLOCK(recent_lock);
99 static DEFINE_MUTEX(recent_mutex);
101 #ifdef CONFIG_PROC_FS
102 static const struct file_operations recent_old_fops, recent_mt_fops;
105 static u_int32_t hash_rnd __read_mostly;
106 static bool hash_rnd_inited __read_mostly;
108 static inline unsigned int recent_entry_hash4(const union nf_inet_addr *addr)
110 return jhash_1word((__force u32)addr->ip, hash_rnd) &
111 (ip_list_hash_size - 1);
114 static inline unsigned int recent_entry_hash6(const union nf_inet_addr *addr)
116 return jhash2((u32 *)addr->ip6, ARRAY_SIZE(addr->ip6), hash_rnd) &
117 (ip_list_hash_size - 1);
120 static struct recent_entry *
121 recent_entry_lookup(const struct recent_table *table,
122 const union nf_inet_addr *addrp, u_int16_t family,
125 struct recent_entry *e;
128 if (family == NFPROTO_IPV4)
129 h = recent_entry_hash4(addrp);
131 h = recent_entry_hash6(addrp);
133 list_for_each_entry(e, &table->iphash[h], list)
134 if (e->family == family &&
135 memcmp(&e->addr, addrp, sizeof(e->addr)) == 0 &&
136 (ttl == e->ttl || ttl == 0 || e->ttl == 0))
141 static void recent_entry_remove(struct recent_table *t, struct recent_entry *e)
144 list_del(&e->lru_list);
149 static struct recent_entry *
150 recent_entry_init(struct recent_table *t, const union nf_inet_addr *addr,
151 u_int16_t family, u_int8_t ttl)
153 struct recent_entry *e;
155 if (t->entries >= ip_list_tot) {
156 e = list_entry(t->lru_list.next, struct recent_entry, lru_list);
157 recent_entry_remove(t, e);
159 e = kmalloc(sizeof(*e) + sizeof(e->stamps[0]) * ip_pkt_list_tot,
163 memcpy(&e->addr, addr, sizeof(e->addr));
165 e->stamps[0] = jiffies;
169 if (family == NFPROTO_IPV4)
170 list_add_tail(&e->list, &t->iphash[recent_entry_hash4(addr)]);
172 list_add_tail(&e->list, &t->iphash[recent_entry_hash6(addr)]);
173 list_add_tail(&e->lru_list, &t->lru_list);
178 static void recent_entry_update(struct recent_table *t, struct recent_entry *e)
180 e->stamps[e->index++] = jiffies;
181 if (e->index > e->nstamps)
182 e->nstamps = e->index;
183 e->index %= ip_pkt_list_tot;
184 list_move_tail(&e->lru_list, &t->lru_list);
187 static struct recent_table *recent_table_lookup(struct recent_net *recent_net,
190 struct recent_table *t;
192 list_for_each_entry(t, &recent_net->tables, list)
193 if (!strcmp(t->name, name))
198 static void recent_table_flush(struct recent_table *t)
200 struct recent_entry *e, *next;
203 for (i = 0; i < ip_list_hash_size; i++)
204 list_for_each_entry_safe(e, next, &t->iphash[i], list)
205 recent_entry_remove(t, e);
209 recent_mt(const struct sk_buff *skb, const struct xt_match_param *par)
211 struct net *net = dev_net(par->in ? par->in : par->out);
212 struct recent_net *recent_net = recent_pernet(net);
213 const struct xt_recent_mtinfo *info = par->matchinfo;
214 struct recent_table *t;
215 struct recent_entry *e;
216 union nf_inet_addr addr = {};
218 bool ret = info->invert;
220 if (par->match->family == NFPROTO_IPV4) {
221 const struct iphdr *iph = ip_hdr(skb);
223 if (info->side == XT_RECENT_DEST)
224 addr.ip = iph->daddr;
226 addr.ip = iph->saddr;
230 const struct ipv6hdr *iph = ipv6_hdr(skb);
232 if (info->side == XT_RECENT_DEST)
233 memcpy(&addr.in6, &iph->daddr, sizeof(addr.in6));
235 memcpy(&addr.in6, &iph->saddr, sizeof(addr.in6));
237 ttl = iph->hop_limit;
240 /* use TTL as seen before forwarding */
241 if (par->out != NULL && skb->sk == NULL)
244 spin_lock_bh(&recent_lock);
245 t = recent_table_lookup(recent_net, info->name);
246 e = recent_entry_lookup(t, &addr, par->match->family,
247 (info->check_set & XT_RECENT_TTL) ? ttl : 0);
249 if (!(info->check_set & XT_RECENT_SET))
251 e = recent_entry_init(t, &addr, par->match->family, ttl);
253 *par->hotdrop = true;
258 if (info->check_set & XT_RECENT_SET)
260 else if (info->check_set & XT_RECENT_REMOVE) {
261 recent_entry_remove(t, e);
263 } else if (info->check_set & (XT_RECENT_CHECK | XT_RECENT_UPDATE)) {
264 unsigned long time = jiffies - info->seconds * HZ;
265 unsigned int i, hits = 0;
267 for (i = 0; i < e->nstamps; i++) {
268 if (info->seconds && time_after(time, e->stamps[i]))
270 if (++hits >= info->hit_count) {
277 if (info->check_set & XT_RECENT_SET ||
278 (info->check_set & XT_RECENT_UPDATE && ret)) {
279 recent_entry_update(t, e);
283 spin_unlock_bh(&recent_lock);
287 static bool recent_mt_check(const struct xt_mtchk_param *par)
289 struct recent_net *recent_net = recent_pernet(par->net);
290 const struct xt_recent_mtinfo *info = par->matchinfo;
291 struct recent_table *t;
292 #ifdef CONFIG_PROC_FS
293 struct proc_dir_entry *pde;
298 if (unlikely(!hash_rnd_inited)) {
299 get_random_bytes(&hash_rnd, sizeof(hash_rnd));
300 hash_rnd_inited = true;
302 if (hweight8(info->check_set &
303 (XT_RECENT_SET | XT_RECENT_REMOVE |
304 XT_RECENT_CHECK | XT_RECENT_UPDATE)) != 1)
306 if ((info->check_set & (XT_RECENT_SET | XT_RECENT_REMOVE)) &&
307 (info->seconds || info->hit_count))
309 if (info->hit_count > ip_pkt_list_tot)
311 if (info->name[0] == '\0' ||
312 strnlen(info->name, XT_RECENT_NAME_LEN) == XT_RECENT_NAME_LEN)
315 mutex_lock(&recent_mutex);
316 t = recent_table_lookup(recent_net, info->name);
323 t = kzalloc(sizeof(*t) + sizeof(t->iphash[0]) * ip_list_hash_size,
328 strcpy(t->name, info->name);
329 INIT_LIST_HEAD(&t->lru_list);
330 for (i = 0; i < ip_list_hash_size; i++)
331 INIT_LIST_HEAD(&t->iphash[i]);
332 #ifdef CONFIG_PROC_FS
333 pde = proc_create_data(t->name, ip_list_perms, recent_net->xt_recent,
339 pde->uid = ip_list_uid;
340 pde->gid = ip_list_gid;
341 #ifdef CONFIG_NETFILTER_XT_MATCH_RECENT_PROC_COMPAT
342 pde = proc_create_data(t->name, ip_list_perms, recent_net->ipt_recent,
343 &recent_old_fops, t);
345 remove_proc_entry(t->name, recent_net->xt_recent);
349 pde->uid = ip_list_uid;
350 pde->gid = ip_list_gid;
353 spin_lock_bh(&recent_lock);
354 list_add_tail(&t->list, &recent_net->tables);
355 spin_unlock_bh(&recent_lock);
358 mutex_unlock(&recent_mutex);
362 static void recent_mt_destroy(const struct xt_mtdtor_param *par)
364 struct recent_net *recent_net = recent_pernet(par->net);
365 const struct xt_recent_mtinfo *info = par->matchinfo;
366 struct recent_table *t;
368 mutex_lock(&recent_mutex);
369 t = recent_table_lookup(recent_net, info->name);
370 if (--t->refcnt == 0) {
371 spin_lock_bh(&recent_lock);
373 spin_unlock_bh(&recent_lock);
374 #ifdef CONFIG_PROC_FS
375 #ifdef CONFIG_NETFILTER_XT_MATCH_RECENT_PROC_COMPAT
376 remove_proc_entry(t->name, recent_net->ipt_recent);
378 remove_proc_entry(t->name, recent_net->xt_recent);
380 recent_table_flush(t);
383 mutex_unlock(&recent_mutex);
386 #ifdef CONFIG_PROC_FS
387 struct recent_iter_state {
388 const struct recent_table *table;
392 static void *recent_seq_start(struct seq_file *seq, loff_t *pos)
393 __acquires(recent_lock)
395 struct recent_iter_state *st = seq->private;
396 const struct recent_table *t = st->table;
397 struct recent_entry *e;
400 spin_lock_bh(&recent_lock);
402 for (st->bucket = 0; st->bucket < ip_list_hash_size; st->bucket++)
403 list_for_each_entry(e, &t->iphash[st->bucket], list)
409 static void *recent_seq_next(struct seq_file *seq, void *v, loff_t *pos)
411 struct recent_iter_state *st = seq->private;
412 const struct recent_table *t = st->table;
413 const struct recent_entry *e = v;
414 const struct list_head *head = e->list.next;
416 while (head == &t->iphash[st->bucket]) {
417 if (++st->bucket >= ip_list_hash_size)
419 head = t->iphash[st->bucket].next;
422 return list_entry(head, struct recent_entry, list);
425 static void recent_seq_stop(struct seq_file *s, void *v)
426 __releases(recent_lock)
428 spin_unlock_bh(&recent_lock);
431 static int recent_seq_show(struct seq_file *seq, void *v)
433 const struct recent_entry *e = v;
436 i = (e->index - 1) % ip_pkt_list_tot;
437 if (e->family == NFPROTO_IPV4)
438 seq_printf(seq, "src=%pI4 ttl: %u last_seen: %lu oldest_pkt: %u",
439 &e->addr.ip, e->ttl, e->stamps[i], e->index);
441 seq_printf(seq, "src=%pI6 ttl: %u last_seen: %lu oldest_pkt: %u",
442 &e->addr.in6, e->ttl, e->stamps[i], e->index);
443 for (i = 0; i < e->nstamps; i++)
444 seq_printf(seq, "%s %lu", i ? "," : "", e->stamps[i]);
445 seq_printf(seq, "\n");
449 static const struct seq_operations recent_seq_ops = {
450 .start = recent_seq_start,
451 .next = recent_seq_next,
452 .stop = recent_seq_stop,
453 .show = recent_seq_show,
456 static int recent_seq_open(struct inode *inode, struct file *file)
458 struct proc_dir_entry *pde = PDE(inode);
459 struct recent_iter_state *st;
461 st = __seq_open_private(file, &recent_seq_ops, sizeof(*st));
465 st->table = pde->data;
469 #ifdef CONFIG_NETFILTER_XT_MATCH_RECENT_PROC_COMPAT
470 static int recent_old_seq_open(struct inode *inode, struct file *filp)
472 static bool warned_of_old;
474 if (unlikely(!warned_of_old)) {
475 printk(KERN_INFO KBUILD_MODNAME ": Use of /proc/net/ipt_recent"
476 " is deprecated; use /proc/net/xt_recent.\n");
477 warned_of_old = true;
479 return recent_seq_open(inode, filp);
482 static ssize_t recent_old_proc_write(struct file *file,
483 const char __user *input,
484 size_t size, loff_t *loff)
486 const struct proc_dir_entry *pde = PDE(file->f_path.dentry->d_inode);
487 struct recent_table *t = pde->data;
488 struct recent_entry *e;
489 char buf[sizeof("+255.255.255.255")], *c = buf;
490 union nf_inet_addr addr = {};
493 if (size > sizeof(buf))
495 if (copy_from_user(buf, input, size))
500 if (size - (c - buf) < 5)
502 if (!strncmp(c, "clear", 5)) {
504 spin_lock_bh(&recent_lock);
505 recent_table_flush(t);
506 spin_unlock_bh(&recent_lock);
521 addr.ip = in_aton(c);
523 spin_lock_bh(&recent_lock);
524 e = recent_entry_lookup(t, &addr, NFPROTO_IPV4, 0);
527 recent_entry_init(t, &addr, NFPROTO_IPV4, 0);
530 recent_entry_update(t, e);
532 recent_entry_remove(t, e);
534 spin_unlock_bh(&recent_lock);
538 static const struct file_operations recent_old_fops = {
539 .open = recent_old_seq_open,
541 .write = recent_old_proc_write,
542 .release = seq_release_private,
543 .owner = THIS_MODULE,
548 recent_mt_proc_write(struct file *file, const char __user *input,
549 size_t size, loff_t *loff)
551 const struct proc_dir_entry *pde = PDE(file->f_path.dentry->d_inode);
552 struct recent_table *t = pde->data;
553 struct recent_entry *e;
554 char buf[sizeof("+b335:1d35:1e55:dead:c0de:1715:5afe:c0de")];
556 union nf_inet_addr addr = {};
562 if (size > sizeof(buf))
564 if (copy_from_user(buf, input, size) != 0)
567 /* Strict protocol! */
571 case '/': /* flush table */
572 spin_lock_bh(&recent_lock);
573 recent_table_flush(t);
574 spin_unlock_bh(&recent_lock);
576 case '-': /* remove address */
579 case '+': /* add address */
583 printk(KERN_INFO KBUILD_MODNAME ": Need +ip, -ip or /\n");
589 if (strnchr(c, size, ':') != NULL) {
590 family = NFPROTO_IPV6;
591 succ = in6_pton(c, size, (void *)&addr, '\n', NULL);
593 family = NFPROTO_IPV4;
594 succ = in4_pton(c, size, (void *)&addr, '\n', NULL);
598 printk(KERN_INFO KBUILD_MODNAME ": illegal address written "
603 spin_lock_bh(&recent_lock);
604 e = recent_entry_lookup(t, &addr, family, 0);
607 recent_entry_init(t, &addr, family, 0);
610 recent_entry_update(t, e);
612 recent_entry_remove(t, e);
614 spin_unlock_bh(&recent_lock);
615 /* Note we removed one above */
620 static const struct file_operations recent_mt_fops = {
621 .open = recent_seq_open,
623 .write = recent_mt_proc_write,
624 .release = seq_release_private,
625 .owner = THIS_MODULE,
628 static int __net_init recent_proc_net_init(struct net *net)
630 struct recent_net *recent_net = recent_pernet(net);
632 recent_net->xt_recent = proc_mkdir("xt_recent", net->proc_net);
633 if (!recent_net->xt_recent)
635 #ifdef CONFIG_NETFILTER_XT_MATCH_RECENT_PROC_COMPAT
636 recent_net->ipt_recent = proc_mkdir("ipt_recent", net->proc_net);
637 if (!recent_net->ipt_recent) {
638 proc_net_remove(net, "xt_recent");
645 static void __net_exit recent_proc_net_exit(struct net *net)
647 #ifdef CONFIG_NETFILTER_XT_MATCH_RECENT_PROC_COMPAT
648 proc_net_remove(net, "ipt_recent");
650 proc_net_remove(net, "xt_recent");
653 static inline int recent_proc_net_init(struct net *net)
658 static inline void recent_proc_net_exit(struct net *net)
661 #endif /* CONFIG_PROC_FS */
663 static int __net_init recent_net_init(struct net *net)
665 struct recent_net *recent_net = recent_pernet(net);
667 INIT_LIST_HEAD(&recent_net->tables);
668 return recent_proc_net_init(net);
671 static void __net_exit recent_net_exit(struct net *net)
673 struct recent_net *recent_net = recent_pernet(net);
675 BUG_ON(!list_empty(&recent_net->tables));
676 recent_proc_net_exit(net);
679 static struct pernet_operations recent_net_ops = {
680 .init = recent_net_init,
681 .exit = recent_net_exit,
682 .id = &recent_net_id,
683 .size = sizeof(struct recent_net),
686 static struct xt_match recent_mt_reg[] __read_mostly = {
690 .family = NFPROTO_IPV4,
692 .matchsize = sizeof(struct xt_recent_mtinfo),
693 .checkentry = recent_mt_check,
694 .destroy = recent_mt_destroy,
700 .family = NFPROTO_IPV6,
702 .matchsize = sizeof(struct xt_recent_mtinfo),
703 .checkentry = recent_mt_check,
704 .destroy = recent_mt_destroy,
709 static int __init recent_mt_init(void)
713 if (!ip_list_tot || !ip_pkt_list_tot || ip_pkt_list_tot > 255)
715 ip_list_hash_size = 1 << fls(ip_list_tot);
717 err = register_pernet_subsys(&recent_net_ops);
720 err = xt_register_matches(recent_mt_reg, ARRAY_SIZE(recent_mt_reg));
722 unregister_pernet_subsys(&recent_net_ops);
726 static void __exit recent_mt_exit(void)
728 xt_unregister_matches(recent_mt_reg, ARRAY_SIZE(recent_mt_reg));
729 unregister_pernet_subsys(&recent_net_ops);
732 module_init(recent_mt_init);
733 module_exit(recent_mt_exit);