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 address 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->index %= ip_pkt_list_tot;
181 e->stamps[e->index++] = jiffies;
182 if (e->index > e->nstamps)
183 e->nstamps = e->index;
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 (info->hit_count && ++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) {
310 pr_info(KBUILD_MODNAME ": hitcount (%u) is larger than "
311 "packets to be remembered (%u)\n",
312 info->hit_count, ip_pkt_list_tot);
315 if (info->name[0] == '\0' ||
316 strnlen(info->name, XT_RECENT_NAME_LEN) == XT_RECENT_NAME_LEN)
319 mutex_lock(&recent_mutex);
320 t = recent_table_lookup(recent_net, info->name);
327 t = kzalloc(sizeof(*t) + sizeof(t->iphash[0]) * ip_list_hash_size,
332 strcpy(t->name, info->name);
333 INIT_LIST_HEAD(&t->lru_list);
334 for (i = 0; i < ip_list_hash_size; i++)
335 INIT_LIST_HEAD(&t->iphash[i]);
336 #ifdef CONFIG_PROC_FS
337 pde = proc_create_data(t->name, ip_list_perms, recent_net->xt_recent,
343 pde->uid = ip_list_uid;
344 pde->gid = ip_list_gid;
345 #ifdef CONFIG_NETFILTER_XT_MATCH_RECENT_PROC_COMPAT
346 pde = proc_create_data(t->name, ip_list_perms, recent_net->ipt_recent,
347 &recent_old_fops, t);
349 remove_proc_entry(t->name, recent_net->xt_recent);
353 pde->uid = ip_list_uid;
354 pde->gid = ip_list_gid;
357 spin_lock_bh(&recent_lock);
358 list_add_tail(&t->list, &recent_net->tables);
359 spin_unlock_bh(&recent_lock);
362 mutex_unlock(&recent_mutex);
366 static void recent_mt_destroy(const struct xt_mtdtor_param *par)
368 struct recent_net *recent_net = recent_pernet(par->net);
369 const struct xt_recent_mtinfo *info = par->matchinfo;
370 struct recent_table *t;
372 mutex_lock(&recent_mutex);
373 t = recent_table_lookup(recent_net, info->name);
374 if (--t->refcnt == 0) {
375 spin_lock_bh(&recent_lock);
377 spin_unlock_bh(&recent_lock);
378 #ifdef CONFIG_PROC_FS
379 #ifdef CONFIG_NETFILTER_XT_MATCH_RECENT_PROC_COMPAT
380 remove_proc_entry(t->name, recent_net->ipt_recent);
382 remove_proc_entry(t->name, recent_net->xt_recent);
384 recent_table_flush(t);
387 mutex_unlock(&recent_mutex);
390 #ifdef CONFIG_PROC_FS
391 struct recent_iter_state {
392 const struct recent_table *table;
396 static void *recent_seq_start(struct seq_file *seq, loff_t *pos)
397 __acquires(recent_lock)
399 struct recent_iter_state *st = seq->private;
400 const struct recent_table *t = st->table;
401 struct recent_entry *e;
404 spin_lock_bh(&recent_lock);
406 for (st->bucket = 0; st->bucket < ip_list_hash_size; st->bucket++)
407 list_for_each_entry(e, &t->iphash[st->bucket], list)
413 static void *recent_seq_next(struct seq_file *seq, void *v, loff_t *pos)
415 struct recent_iter_state *st = seq->private;
416 const struct recent_table *t = st->table;
417 const struct recent_entry *e = v;
418 const struct list_head *head = e->list.next;
420 while (head == &t->iphash[st->bucket]) {
421 if (++st->bucket >= ip_list_hash_size)
423 head = t->iphash[st->bucket].next;
426 return list_entry(head, struct recent_entry, list);
429 static void recent_seq_stop(struct seq_file *s, void *v)
430 __releases(recent_lock)
432 spin_unlock_bh(&recent_lock);
435 static int recent_seq_show(struct seq_file *seq, void *v)
437 const struct recent_entry *e = v;
440 i = (e->index - 1) % ip_pkt_list_tot;
441 if (e->family == NFPROTO_IPV4)
442 seq_printf(seq, "src=%pI4 ttl: %u last_seen: %lu oldest_pkt: %u",
443 &e->addr.ip, e->ttl, e->stamps[i], e->index);
445 seq_printf(seq, "src=%pI6 ttl: %u last_seen: %lu oldest_pkt: %u",
446 &e->addr.in6, e->ttl, e->stamps[i], e->index);
447 for (i = 0; i < e->nstamps; i++)
448 seq_printf(seq, "%s %lu", i ? "," : "", e->stamps[i]);
449 seq_printf(seq, "\n");
453 static const struct seq_operations recent_seq_ops = {
454 .start = recent_seq_start,
455 .next = recent_seq_next,
456 .stop = recent_seq_stop,
457 .show = recent_seq_show,
460 static int recent_seq_open(struct inode *inode, struct file *file)
462 struct proc_dir_entry *pde = PDE(inode);
463 struct recent_iter_state *st;
465 st = __seq_open_private(file, &recent_seq_ops, sizeof(*st));
469 st->table = pde->data;
473 #ifdef CONFIG_NETFILTER_XT_MATCH_RECENT_PROC_COMPAT
474 static int recent_old_seq_open(struct inode *inode, struct file *filp)
476 static bool warned_of_old;
478 if (unlikely(!warned_of_old)) {
479 printk(KERN_INFO KBUILD_MODNAME ": Use of /proc/net/ipt_recent"
480 " is deprecated; use /proc/net/xt_recent.\n");
481 warned_of_old = true;
483 return recent_seq_open(inode, filp);
486 static ssize_t recent_old_proc_write(struct file *file,
487 const char __user *input,
488 size_t size, loff_t *loff)
490 const struct proc_dir_entry *pde = PDE(file->f_path.dentry->d_inode);
491 struct recent_table *t = pde->data;
492 struct recent_entry *e;
493 char buf[sizeof("+255.255.255.255")], *c = buf;
494 union nf_inet_addr addr = {};
497 if (size > sizeof(buf))
499 if (copy_from_user(buf, input, size))
504 if (size - (c - buf) < 5)
506 if (!strncmp(c, "clear", 5)) {
508 spin_lock_bh(&recent_lock);
509 recent_table_flush(t);
510 spin_unlock_bh(&recent_lock);
525 addr.ip = in_aton(c);
527 spin_lock_bh(&recent_lock);
528 e = recent_entry_lookup(t, &addr, NFPROTO_IPV4, 0);
531 recent_entry_init(t, &addr, NFPROTO_IPV4, 0);
534 recent_entry_update(t, e);
536 recent_entry_remove(t, e);
538 spin_unlock_bh(&recent_lock);
542 static const struct file_operations recent_old_fops = {
543 .open = recent_old_seq_open,
545 .write = recent_old_proc_write,
546 .release = seq_release_private,
547 .owner = THIS_MODULE,
552 recent_mt_proc_write(struct file *file, const char __user *input,
553 size_t size, loff_t *loff)
555 const struct proc_dir_entry *pde = PDE(file->f_path.dentry->d_inode);
556 struct recent_table *t = pde->data;
557 struct recent_entry *e;
558 char buf[sizeof("+b335:1d35:1e55:dead:c0de:1715:5afe:c0de")];
560 union nf_inet_addr addr = {};
566 if (size > sizeof(buf))
568 if (copy_from_user(buf, input, size) != 0)
571 /* Strict protocol! */
575 case '/': /* flush table */
576 spin_lock_bh(&recent_lock);
577 recent_table_flush(t);
578 spin_unlock_bh(&recent_lock);
580 case '-': /* remove address */
583 case '+': /* add address */
587 printk(KERN_INFO KBUILD_MODNAME ": Need +ip, -ip or /\n");
593 if (strnchr(c, size, ':') != NULL) {
594 family = NFPROTO_IPV6;
595 succ = in6_pton(c, size, (void *)&addr, '\n', NULL);
597 family = NFPROTO_IPV4;
598 succ = in4_pton(c, size, (void *)&addr, '\n', NULL);
602 printk(KERN_INFO KBUILD_MODNAME ": illegal address written "
607 spin_lock_bh(&recent_lock);
608 e = recent_entry_lookup(t, &addr, family, 0);
611 recent_entry_init(t, &addr, family, 0);
614 recent_entry_update(t, e);
616 recent_entry_remove(t, e);
618 spin_unlock_bh(&recent_lock);
619 /* Note we removed one above */
624 static const struct file_operations recent_mt_fops = {
625 .open = recent_seq_open,
627 .write = recent_mt_proc_write,
628 .release = seq_release_private,
629 .owner = THIS_MODULE,
632 static int __net_init recent_proc_net_init(struct net *net)
634 struct recent_net *recent_net = recent_pernet(net);
636 recent_net->xt_recent = proc_mkdir("xt_recent", net->proc_net);
637 if (!recent_net->xt_recent)
639 #ifdef CONFIG_NETFILTER_XT_MATCH_RECENT_PROC_COMPAT
640 recent_net->ipt_recent = proc_mkdir("ipt_recent", net->proc_net);
641 if (!recent_net->ipt_recent) {
642 proc_net_remove(net, "xt_recent");
649 static void __net_exit recent_proc_net_exit(struct net *net)
651 #ifdef CONFIG_NETFILTER_XT_MATCH_RECENT_PROC_COMPAT
652 proc_net_remove(net, "ipt_recent");
654 proc_net_remove(net, "xt_recent");
657 static inline int recent_proc_net_init(struct net *net)
662 static inline void recent_proc_net_exit(struct net *net)
665 #endif /* CONFIG_PROC_FS */
667 static int __net_init recent_net_init(struct net *net)
669 struct recent_net *recent_net = recent_pernet(net);
671 INIT_LIST_HEAD(&recent_net->tables);
672 return recent_proc_net_init(net);
675 static void __net_exit recent_net_exit(struct net *net)
677 struct recent_net *recent_net = recent_pernet(net);
679 BUG_ON(!list_empty(&recent_net->tables));
680 recent_proc_net_exit(net);
683 static struct pernet_operations recent_net_ops = {
684 .init = recent_net_init,
685 .exit = recent_net_exit,
686 .id = &recent_net_id,
687 .size = sizeof(struct recent_net),
690 static struct xt_match recent_mt_reg[] __read_mostly = {
694 .family = NFPROTO_IPV4,
696 .matchsize = sizeof(struct xt_recent_mtinfo),
697 .checkentry = recent_mt_check,
698 .destroy = recent_mt_destroy,
704 .family = NFPROTO_IPV6,
706 .matchsize = sizeof(struct xt_recent_mtinfo),
707 .checkentry = recent_mt_check,
708 .destroy = recent_mt_destroy,
713 static int __init recent_mt_init(void)
717 if (!ip_list_tot || !ip_pkt_list_tot || ip_pkt_list_tot > 255)
719 ip_list_hash_size = 1 << fls(ip_list_tot);
721 err = register_pernet_subsys(&recent_net_ops);
724 err = xt_register_matches(recent_mt_reg, ARRAY_SIZE(recent_mt_reg));
726 unregister_pernet_subsys(&recent_net_ops);
730 static void __exit recent_mt_exit(void)
732 xt_unregister_matches(recent_mt_reg, ARRAY_SIZE(recent_mt_reg));
733 unregister_pernet_subsys(&recent_net_ops);
736 module_init(recent_mt_init);
737 module_exit(recent_mt_exit);