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);
284 recent_mt_check(const char *tablename, const void *ip,
285 const struct xt_match *match, void *matchinfo,
286 unsigned int hook_mask)
288 const struct xt_recent_mtinfo *info = matchinfo;
289 struct recent_table *t;
293 if (hweight8(info->check_set &
294 (XT_RECENT_SET | XT_RECENT_REMOVE |
295 XT_RECENT_CHECK | XT_RECENT_UPDATE)) != 1)
297 if ((info->check_set & (XT_RECENT_SET | XT_RECENT_REMOVE)) &&
298 (info->seconds || info->hit_count))
300 if (info->hit_count > ip_pkt_list_tot)
302 if (info->name[0] == '\0' ||
303 strnlen(info->name, XT_RECENT_NAME_LEN) == XT_RECENT_NAME_LEN)
306 mutex_lock(&recent_mutex);
307 t = recent_table_lookup(info->name);
314 t = kzalloc(sizeof(*t) + sizeof(t->iphash[0]) * ip_list_hash_size,
319 strcpy(t->name, info->name);
320 INIT_LIST_HEAD(&t->lru_list);
321 for (i = 0; i < ip_list_hash_size; i++)
322 INIT_LIST_HEAD(&t->iphash[i]);
323 #ifdef CONFIG_PROC_FS
324 t->proc = proc_create(t->name, ip_list_perms, recent_proc_dir,
326 if (t->proc == NULL) {
330 #ifdef CONFIG_NETFILTER_XT_MATCH_RECENT_PROC_COMPAT
331 t->proc_old = proc_create(t->name, ip_list_perms, proc_old_dir,
333 if (t->proc_old == NULL) {
334 remove_proc_entry(t->name, proc_old_dir);
338 t->proc_old->uid = ip_list_uid;
339 t->proc_old->gid = ip_list_gid;
340 t->proc_old->data = t;
342 t->proc->uid = ip_list_uid;
343 t->proc->gid = ip_list_gid;
346 spin_lock_bh(&recent_lock);
347 list_add_tail(&t->list, &tables);
348 spin_unlock_bh(&recent_lock);
351 mutex_unlock(&recent_mutex);
355 static void recent_mt_destroy(const struct xt_match *match, void *matchinfo)
357 const struct xt_recent_mtinfo *info = matchinfo;
358 struct recent_table *t;
360 mutex_lock(&recent_mutex);
361 t = recent_table_lookup(info->name);
362 if (--t->refcnt == 0) {
363 spin_lock_bh(&recent_lock);
365 spin_unlock_bh(&recent_lock);
366 #ifdef CONFIG_PROC_FS
367 #ifdef CONFIG_NETFILTER_XT_MATCH_RECENT_PROC_COMPAT
368 remove_proc_entry(t->name, proc_old_dir);
370 remove_proc_entry(t->name, recent_proc_dir);
372 recent_table_flush(t);
375 mutex_unlock(&recent_mutex);
378 #ifdef CONFIG_PROC_FS
379 struct recent_iter_state {
380 const struct recent_table *table;
384 static void *recent_seq_start(struct seq_file *seq, loff_t *pos)
385 __acquires(recent_lock)
387 struct recent_iter_state *st = seq->private;
388 const struct recent_table *t = st->table;
389 struct recent_entry *e;
392 spin_lock_bh(&recent_lock);
394 for (st->bucket = 0; st->bucket < ip_list_hash_size; st->bucket++)
395 list_for_each_entry(e, &t->iphash[st->bucket], list)
401 static void *recent_seq_next(struct seq_file *seq, void *v, loff_t *pos)
403 struct recent_iter_state *st = seq->private;
404 const struct recent_table *t = st->table;
405 const struct recent_entry *e = v;
406 const struct list_head *head = e->list.next;
408 while (head == &t->iphash[st->bucket]) {
409 if (++st->bucket >= ip_list_hash_size)
411 head = t->iphash[st->bucket].next;
414 return list_entry(head, struct recent_entry, list);
417 static void recent_seq_stop(struct seq_file *s, void *v)
418 __releases(recent_lock)
420 spin_unlock_bh(&recent_lock);
423 static int recent_seq_show(struct seq_file *seq, void *v)
425 const struct recent_entry *e = v;
428 i = (e->index - 1) % ip_pkt_list_tot;
429 if (e->family == NFPROTO_IPV4)
430 seq_printf(seq, "src=" NIPQUAD_FMT " ttl: %u last_seen: %lu "
431 "oldest_pkt: %u", NIPQUAD(e->addr.ip), e->ttl,
432 e->stamps[i], e->index);
434 seq_printf(seq, "src=" NIP6_FMT " ttl: %u last_seen: %lu "
435 "oldest_pkt: %u", NIP6(e->addr.in6), e->ttl,
436 e->stamps[i], e->index);
437 for (i = 0; i < e->nstamps; i++)
438 seq_printf(seq, "%s %lu", i ? "," : "", e->stamps[i]);
439 seq_printf(seq, "\n");
443 static const struct seq_operations recent_seq_ops = {
444 .start = recent_seq_start,
445 .next = recent_seq_next,
446 .stop = recent_seq_stop,
447 .show = recent_seq_show,
450 static int recent_seq_open(struct inode *inode, struct file *file)
452 struct proc_dir_entry *pde = PDE(inode);
453 struct recent_iter_state *st;
455 st = __seq_open_private(file, &recent_seq_ops, sizeof(*st));
459 st->table = pde->data;
463 #ifdef CONFIG_NETFILTER_XT_MATCH_RECENT_PROC_COMPAT
464 static int recent_old_seq_open(struct inode *inode, struct file *filp)
466 static bool warned_of_old;
468 if (unlikely(!warned_of_old)) {
469 printk(KERN_INFO KBUILD_MODNAME ": Use of /proc/net/ipt_recent"
470 " is deprecated; use /proc/net/xt_recent.\n");
471 warned_of_old = true;
473 return recent_seq_open(inode, filp);
476 static ssize_t recent_old_proc_write(struct file *file,
477 const char __user *input,
478 size_t size, loff_t *loff)
480 const struct proc_dir_entry *pde = PDE(file->f_path.dentry->d_inode);
481 struct recent_table *t = pde->data;
482 struct recent_entry *e;
483 char buf[sizeof("+255.255.255.255")], *c = buf;
487 if (size > sizeof(buf))
489 if (copy_from_user(buf, input, size))
495 if (size - (c - buf) < 5)
497 if (!strncmp(c, "clear", 5)) {
499 spin_lock_bh(&recent_lock);
500 recent_table_flush(t);
501 spin_unlock_bh(&recent_lock);
518 spin_lock_bh(&recent_lock);
519 e = recent_entry_lookup(t, (const void *)&addr, NFPROTO_IPV4, 0);
522 recent_entry_init(t, (const void *)&addr,
526 recent_entry_update(t, e);
528 recent_entry_remove(t, e);
530 spin_unlock_bh(&recent_lock);
534 static const struct file_operations recent_old_fops = {
535 .open = recent_old_seq_open,
537 .write = recent_old_proc_write,
538 .release = seq_release_private,
539 .owner = THIS_MODULE,
544 recent_mt_proc_write(struct file *file, const char __user *input,
545 size_t size, loff_t *loff)
547 const struct proc_dir_entry *pde = PDE(file->f_path.dentry->d_inode);
548 struct recent_table *t = pde->data;
549 struct recent_entry *e;
550 char buf[sizeof("+b335:1d35:1e55:dead:c0de:1715:5afe:c0de")];
552 union nf_inet_addr addr;
558 if (size > sizeof(buf))
560 if (copy_from_user(buf, input, size) != 0)
563 /* Strict protocol! */
567 case '/': /* flush table */
568 spin_lock_bh(&recent_lock);
569 recent_table_flush(t);
570 spin_unlock_bh(&recent_lock);
572 case '-': /* remove address */
575 case '+': /* add address */
579 printk(KERN_INFO KBUILD_MODNAME ": Need +ip, -ip or /\n");
585 if (strnchr(c, size, ':') != NULL) {
586 family = NFPROTO_IPV6;
587 succ = in6_pton(c, size, (void *)&addr, '\n', NULL);
589 family = NFPROTO_IPV4;
590 succ = in4_pton(c, size, (void *)&addr, '\n', NULL);
594 printk(KERN_INFO KBUILD_MODNAME ": illegal address written "
599 spin_lock_bh(&recent_lock);
600 e = recent_entry_lookup(t, &addr, family, 0);
603 recent_entry_init(t, &addr, family, 0);
606 recent_entry_update(t, e);
608 recent_entry_remove(t, e);
610 spin_unlock_bh(&recent_lock);
611 /* Note we removed one above */
616 static const struct file_operations recent_mt_fops = {
617 .open = recent_seq_open,
619 .write = recent_mt_proc_write,
620 .release = seq_release_private,
621 .owner = THIS_MODULE,
623 #endif /* CONFIG_PROC_FS */
625 static struct xt_match recent_mt_reg[] __read_mostly = {
629 .family = NFPROTO_IPV4,
631 .matchsize = sizeof(struct xt_recent_mtinfo),
632 .checkentry = recent_mt_check,
633 .destroy = recent_mt_destroy,
639 .family = NFPROTO_IPV6,
641 .matchsize = sizeof(struct xt_recent_mtinfo),
642 .checkentry = recent_mt_check,
643 .destroy = recent_mt_destroy,
648 static int __init recent_mt_init(void)
652 if (!ip_list_tot || !ip_pkt_list_tot || ip_pkt_list_tot > 255)
654 ip_list_hash_size = 1 << fls(ip_list_tot);
656 err = xt_register_matches(recent_mt_reg, ARRAY_SIZE(recent_mt_reg));
657 #ifdef CONFIG_PROC_FS
660 recent_proc_dir = proc_mkdir("xt_recent", init_net.proc_net);
661 if (recent_proc_dir == NULL) {
662 xt_unregister_matches(recent_mt_reg, ARRAY_SIZE(recent_mt_reg));
665 #ifdef CONFIG_NETFILTER_XT_MATCH_RECENT_PROC_COMPAT
668 proc_old_dir = proc_mkdir("ipt_recent", init_net.proc_net);
669 if (proc_old_dir == NULL) {
670 remove_proc_entry("xt_recent", init_net.proc_net);
671 xt_unregister_matches(recent_mt_reg, ARRAY_SIZE(recent_mt_reg));
679 static void __exit recent_mt_exit(void)
681 BUG_ON(!list_empty(&tables));
682 xt_unregister_matches(recent_mt_reg, ARRAY_SIZE(recent_mt_reg));
683 #ifdef CONFIG_PROC_FS
684 #ifdef CONFIG_NETFILTER_XT_MATCH_RECENT_PROC_COMPAT
685 remove_proc_entry("ipt_recent", init_net.proc_net);
687 remove_proc_entry("xt_recent", init_net.proc_net);
691 module_init(recent_mt_init);
692 module_exit(recent_mt_exit);