2 * Copyright (c) 2006 Patrick McHardy <kaber@trash.net>
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License version 2 as
6 * published by the Free Software Foundation.
8 * This is a replacement of the old ipt_recent module, which carried the
9 * following copyright notice:
11 * Author: Stephen Frost <sfrost@snowman.net>
12 * Copyright 2002-2003, Stephen Frost, 2.5.x port by laforge@netfilter.org
14 #include <linux/init.h>
16 #include <linux/moduleparam.h>
17 #include <linux/proc_fs.h>
18 #include <linux/seq_file.h>
19 #include <linux/string.h>
20 #include <linux/ctype.h>
21 #include <linux/list.h>
22 #include <linux/random.h>
23 #include <linux/jhash.h>
24 #include <linux/bitops.h>
25 #include <linux/skbuff.h>
26 #include <linux/inet.h>
27 #include <net/net_namespace.h>
29 #include <linux/netfilter/x_tables.h>
30 #include <linux/netfilter/xt_recent.h>
32 MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");
33 MODULE_DESCRIPTION("Xtables: \"recently-seen\" host matching for IPv4");
34 MODULE_LICENSE("GPL");
35 MODULE_ALIAS("ipt_recent");
37 static unsigned int ip_list_tot = 100;
38 static unsigned int ip_pkt_list_tot = 20;
39 static unsigned int ip_list_hash_size = 0;
40 static unsigned int ip_list_perms = 0644;
41 static unsigned int ip_list_uid = 0;
42 static unsigned int ip_list_gid = 0;
43 module_param(ip_list_tot, uint, 0400);
44 module_param(ip_pkt_list_tot, uint, 0400);
45 module_param(ip_list_hash_size, uint, 0400);
46 module_param(ip_list_perms, uint, 0400);
47 module_param(ip_list_uid, uint, 0400);
48 module_param(ip_list_gid, uint, 0400);
49 MODULE_PARM_DESC(ip_list_tot, "number of IPs to remember per list");
50 MODULE_PARM_DESC(ip_pkt_list_tot, "number of packets per IP to remember (max. 255)");
51 MODULE_PARM_DESC(ip_list_hash_size, "size of hash table used to look up IPs");
52 MODULE_PARM_DESC(ip_list_perms, "permissions on /proc/net/ipt_recent/* files");
53 MODULE_PARM_DESC(ip_list_uid,"owner of /proc/net/ipt_recent/* files");
54 MODULE_PARM_DESC(ip_list_gid,"owning group of /proc/net/ipt_recent/* files");
57 struct list_head list;
58 struct list_head lru_list;
63 unsigned long stamps[0];
67 struct list_head list;
68 char name[XT_RECENT_NAME_LEN];
70 struct proc_dir_entry *proc;
74 struct list_head lru_list;
75 struct list_head iphash[0];
78 static LIST_HEAD(tables);
79 static DEFINE_SPINLOCK(recent_lock);
80 static DEFINE_MUTEX(recent_mutex);
83 static struct proc_dir_entry *proc_dir;
84 static const struct file_operations recent_fops;
87 static u_int32_t hash_rnd;
88 static int hash_rnd_initted;
90 static unsigned int recent_entry_hash(__be32 addr)
92 if (!hash_rnd_initted) {
93 get_random_bytes(&hash_rnd, 4);
96 return jhash_1word((__force u32)addr, hash_rnd) & (ip_list_hash_size - 1);
99 static struct recent_entry *
100 recent_entry_lookup(const struct recent_table *table, __be32 addr, u_int8_t ttl)
102 struct recent_entry *e;
105 h = recent_entry_hash(addr);
106 list_for_each_entry(e, &table->iphash[h], list)
107 if (e->addr == addr && (ttl == e->ttl || !ttl || !e->ttl))
112 static void recent_entry_remove(struct recent_table *t, struct recent_entry *e)
115 list_del(&e->lru_list);
120 static struct recent_entry *
121 recent_entry_init(struct recent_table *t, __be32 addr, u_int8_t ttl)
123 struct recent_entry *e;
125 if (t->entries >= ip_list_tot) {
126 e = list_entry(t->lru_list.next, struct recent_entry, lru_list);
127 recent_entry_remove(t, e);
129 e = kmalloc(sizeof(*e) + sizeof(e->stamps[0]) * ip_pkt_list_tot,
135 e->stamps[0] = jiffies;
138 list_add_tail(&e->list, &t->iphash[recent_entry_hash(addr)]);
139 list_add_tail(&e->lru_list, &t->lru_list);
144 static void recent_entry_update(struct recent_table *t, struct recent_entry *e)
146 e->stamps[e->index++] = jiffies;
147 if (e->index > e->nstamps)
148 e->nstamps = e->index;
149 e->index %= ip_pkt_list_tot;
150 list_move_tail(&e->lru_list, &t->lru_list);
153 static struct recent_table *recent_table_lookup(const char *name)
155 struct recent_table *t;
157 list_for_each_entry(t, &tables, list)
158 if (!strcmp(t->name, name))
163 static void recent_table_flush(struct recent_table *t)
165 struct recent_entry *e, *next;
168 for (i = 0; i < ip_list_hash_size; i++)
169 list_for_each_entry_safe(e, next, &t->iphash[i], list)
170 recent_entry_remove(t, e);
174 recent_mt(const struct sk_buff *skb, const struct net_device *in,
175 const struct net_device *out, const struct xt_match *match,
176 const void *matchinfo, int offset, unsigned int protoff,
179 const struct xt_recent_mtinfo *info = matchinfo;
180 struct recent_table *t;
181 struct recent_entry *e;
184 bool ret = info->invert;
186 if (info->side == XT_RECENT_DEST)
187 addr = ip_hdr(skb)->daddr;
189 addr = ip_hdr(skb)->saddr;
191 ttl = ip_hdr(skb)->ttl;
192 /* use TTL as seen before forwarding */
196 spin_lock_bh(&recent_lock);
197 t = recent_table_lookup(info->name);
198 e = recent_entry_lookup(t, addr,
199 info->check_set & XT_RECENT_TTL ? ttl : 0);
201 if (!(info->check_set & XT_RECENT_SET))
203 e = recent_entry_init(t, addr, ttl);
210 if (info->check_set & XT_RECENT_SET)
212 else if (info->check_set & XT_RECENT_REMOVE) {
213 recent_entry_remove(t, e);
215 } else if (info->check_set & (XT_RECENT_CHECK | XT_RECENT_UPDATE)) {
216 unsigned long time = jiffies - info->seconds * HZ;
217 unsigned int i, hits = 0;
219 for (i = 0; i < e->nstamps; i++) {
220 if (info->seconds && time_after(time, e->stamps[i]))
222 if (++hits >= info->hit_count) {
229 if (info->check_set & XT_RECENT_SET ||
230 (info->check_set & XT_RECENT_UPDATE && ret)) {
231 recent_entry_update(t, e);
235 spin_unlock_bh(&recent_lock);
240 recent_mt_check(const char *tablename, const void *ip,
241 const struct xt_match *match, void *matchinfo,
242 unsigned int hook_mask)
244 const struct xt_recent_mtinfo *info = matchinfo;
245 struct recent_table *t;
249 if (hweight8(info->check_set &
250 (XT_RECENT_SET | XT_RECENT_REMOVE |
251 XT_RECENT_CHECK | XT_RECENT_UPDATE)) != 1)
253 if ((info->check_set & (XT_RECENT_SET | XT_RECENT_REMOVE)) &&
254 (info->seconds || info->hit_count))
256 if (info->hit_count > ip_pkt_list_tot)
258 if (info->name[0] == '\0' ||
259 strnlen(info->name, XT_RECENT_NAME_LEN) == XT_RECENT_NAME_LEN)
262 mutex_lock(&recent_mutex);
263 t = recent_table_lookup(info->name);
270 t = kzalloc(sizeof(*t) + sizeof(t->iphash[0]) * ip_list_hash_size,
275 strcpy(t->name, info->name);
276 INIT_LIST_HEAD(&t->lru_list);
277 for (i = 0; i < ip_list_hash_size; i++)
278 INIT_LIST_HEAD(&t->iphash[i]);
279 #ifdef CONFIG_PROC_FS
280 t->proc = proc_create(t->name, ip_list_perms, proc_dir, &recent_fops);
281 if (t->proc == NULL) {
285 t->proc->uid = ip_list_uid;
286 t->proc->gid = ip_list_gid;
289 spin_lock_bh(&recent_lock);
290 list_add_tail(&t->list, &tables);
291 spin_unlock_bh(&recent_lock);
294 mutex_unlock(&recent_mutex);
298 static void recent_mt_destroy(const struct xt_match *match, void *matchinfo)
300 const struct xt_recent_mtinfo *info = matchinfo;
301 struct recent_table *t;
303 mutex_lock(&recent_mutex);
304 t = recent_table_lookup(info->name);
305 if (--t->refcnt == 0) {
306 spin_lock_bh(&recent_lock);
308 spin_unlock_bh(&recent_lock);
309 #ifdef CONFIG_PROC_FS
310 remove_proc_entry(t->name, proc_dir);
312 recent_table_flush(t);
315 mutex_unlock(&recent_mutex);
318 #ifdef CONFIG_PROC_FS
319 struct recent_iter_state {
320 struct recent_table *table;
324 static void *recent_seq_start(struct seq_file *seq, loff_t *pos)
325 __acquires(recent_lock)
327 struct recent_iter_state *st = seq->private;
328 const struct recent_table *t = st->table;
329 struct recent_entry *e;
332 spin_lock_bh(&recent_lock);
334 for (st->bucket = 0; st->bucket < ip_list_hash_size; st->bucket++)
335 list_for_each_entry(e, &t->iphash[st->bucket], list)
341 static void *recent_seq_next(struct seq_file *seq, void *v, loff_t *pos)
343 struct recent_iter_state *st = seq->private;
344 const struct recent_table *t = st->table;
345 struct recent_entry *e = v;
346 struct list_head *head = e->list.next;
348 while (head == &t->iphash[st->bucket]) {
349 if (++st->bucket >= ip_list_hash_size)
351 head = t->iphash[st->bucket].next;
354 return list_entry(head, struct recent_entry, list);
357 static void recent_seq_stop(struct seq_file *s, void *v)
358 __releases(recent_lock)
360 spin_unlock_bh(&recent_lock);
363 static int recent_seq_show(struct seq_file *seq, void *v)
365 const struct recent_entry *e = v;
368 i = (e->index - 1) % ip_pkt_list_tot;
369 seq_printf(seq, "src=%u.%u.%u.%u ttl: %u last_seen: %lu oldest_pkt: %u",
370 NIPQUAD(e->addr), e->ttl, e->stamps[i], e->index);
371 for (i = 0; i < e->nstamps; i++)
372 seq_printf(seq, "%s %lu", i ? "," : "", e->stamps[i]);
373 seq_printf(seq, "\n");
377 static const struct seq_operations recent_seq_ops = {
378 .start = recent_seq_start,
379 .next = recent_seq_next,
380 .stop = recent_seq_stop,
381 .show = recent_seq_show,
384 static int recent_seq_open(struct inode *inode, struct file *file)
386 struct proc_dir_entry *pde = PDE(inode);
387 struct recent_iter_state *st;
389 st = __seq_open_private(file, &recent_seq_ops, sizeof(*st));
393 st->table = pde->data;
397 static ssize_t recent_proc_write(struct file *file, const char __user *input,
398 size_t size, loff_t *loff)
400 const struct proc_dir_entry *pde = PDE(file->f_path.dentry->d_inode);
401 struct recent_table *t = pde->data;
402 struct recent_entry *e;
403 char buf[sizeof("+255.255.255.255")], *c = buf;
407 if (size > sizeof(buf))
409 if (copy_from_user(buf, input, size))
414 if (size - (c - buf) < 5)
416 if (!strncmp(c, "clear", 5)) {
418 spin_lock_bh(&recent_lock);
419 recent_table_flush(t);
420 spin_unlock_bh(&recent_lock);
437 spin_lock_bh(&recent_lock);
438 e = recent_entry_lookup(t, addr, 0);
441 recent_entry_init(t, addr, 0);
444 recent_entry_update(t, e);
446 recent_entry_remove(t, e);
448 spin_unlock_bh(&recent_lock);
452 static const struct file_operations recent_fops = {
453 .open = recent_seq_open,
455 .write = recent_proc_write,
456 .release = seq_release_private,
457 .owner = THIS_MODULE,
459 #endif /* CONFIG_PROC_FS */
461 static struct xt_match recent_mt_reg __read_mostly = {
465 .matchsize = sizeof(struct xt_recent_mtinfo),
466 .checkentry = recent_mt_check,
467 .destroy = recent_mt_destroy,
471 static int __init recent_mt_init(void)
475 if (!ip_list_tot || !ip_pkt_list_tot || ip_pkt_list_tot > 255)
477 ip_list_hash_size = 1 << fls(ip_list_tot);
479 err = xt_register_match(&recent_mt_reg);
480 #ifdef CONFIG_PROC_FS
483 proc_dir = proc_mkdir("ipt_recent", init_net.proc_net);
484 if (proc_dir == NULL) {
485 xt_unregister_match(&recent_mt_reg);
492 static void __exit recent_mt_exit(void)
494 BUG_ON(!list_empty(&tables));
495 xt_unregister_match(&recent_mt_reg);
496 #ifdef CONFIG_PROC_FS
497 remove_proc_entry("ipt_recent", init_net.proc_net);
501 module_init(recent_mt_init);
502 module_exit(recent_mt_exit);