swh:1:snp:c3bf2749e3476071fa748f67b0ffa2fdc5fe49d9
Tip revision: 49914084e797530d9baaf51df9eda77babc98fa8 authored by Linus Torvalds on 24 January 2008, 22:58:37 UTC
Linux 2.6.24
Linux 2.6.24
Tip revision: 4991408
ipt_recent.c
/*
* Copyright (c) 2006 Patrick McHardy <kaber@trash.net>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
* This is a replacement of the old ipt_recent module, which carried the
* following copyright notice:
*
* Author: Stephen Frost <sfrost@snowman.net>
* Copyright 2002-2003, Stephen Frost, 2.5.x port by laforge@netfilter.org
*/
#include <linux/init.h>
#include <linux/ip.h>
#include <linux/moduleparam.h>
#include <linux/proc_fs.h>
#include <linux/seq_file.h>
#include <linux/string.h>
#include <linux/ctype.h>
#include <linux/list.h>
#include <linux/random.h>
#include <linux/jhash.h>
#include <linux/bitops.h>
#include <linux/skbuff.h>
#include <linux/inet.h>
#include <net/net_namespace.h>
#include <linux/netfilter/x_tables.h>
#include <linux/netfilter_ipv4/ipt_recent.h>
MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");
MODULE_DESCRIPTION("IP tables recently seen matching module");
MODULE_LICENSE("GPL");
static unsigned int ip_list_tot = 100;
static unsigned int ip_pkt_list_tot = 20;
static unsigned int ip_list_hash_size = 0;
static unsigned int ip_list_perms = 0644;
static unsigned int ip_list_uid = 0;
static unsigned int ip_list_gid = 0;
module_param(ip_list_tot, uint, 0400);
module_param(ip_pkt_list_tot, uint, 0400);
module_param(ip_list_hash_size, uint, 0400);
module_param(ip_list_perms, uint, 0400);
module_param(ip_list_uid, uint, 0400);
module_param(ip_list_gid, uint, 0400);
MODULE_PARM_DESC(ip_list_tot, "number of IPs to remember per list");
MODULE_PARM_DESC(ip_pkt_list_tot, "number of packets per IP to remember (max. 255)");
MODULE_PARM_DESC(ip_list_hash_size, "size of hash table used to look up IPs");
MODULE_PARM_DESC(ip_list_perms, "permissions on /proc/net/ipt_recent/* files");
MODULE_PARM_DESC(ip_list_uid,"owner of /proc/net/ipt_recent/* files");
MODULE_PARM_DESC(ip_list_gid,"owning group of /proc/net/ipt_recent/* files");
struct recent_entry {
struct list_head list;
struct list_head lru_list;
__be32 addr;
u_int8_t ttl;
u_int8_t index;
u_int16_t nstamps;
unsigned long stamps[0];
};
struct recent_table {
struct list_head list;
char name[IPT_RECENT_NAME_LEN];
#ifdef CONFIG_PROC_FS
struct proc_dir_entry *proc;
#endif
unsigned int refcnt;
unsigned int entries;
struct list_head lru_list;
struct list_head iphash[0];
};
static LIST_HEAD(tables);
static DEFINE_SPINLOCK(recent_lock);
static DEFINE_MUTEX(recent_mutex);
#ifdef CONFIG_PROC_FS
static struct proc_dir_entry *proc_dir;
static const struct file_operations recent_fops;
#endif
static u_int32_t hash_rnd;
static int hash_rnd_initted;
static unsigned int recent_entry_hash(__be32 addr)
{
if (!hash_rnd_initted) {
get_random_bytes(&hash_rnd, 4);
hash_rnd_initted = 1;
}
return jhash_1word((__force u32)addr, hash_rnd) & (ip_list_hash_size - 1);
}
static struct recent_entry *
recent_entry_lookup(const struct recent_table *table, __be32 addr, u_int8_t ttl)
{
struct recent_entry *e;
unsigned int h;
h = recent_entry_hash(addr);
list_for_each_entry(e, &table->iphash[h], list)
if (e->addr == addr && (ttl == e->ttl || !ttl || !e->ttl))
return e;
return NULL;
}
static void recent_entry_remove(struct recent_table *t, struct recent_entry *e)
{
list_del(&e->list);
list_del(&e->lru_list);
kfree(e);
t->entries--;
}
static struct recent_entry *
recent_entry_init(struct recent_table *t, __be32 addr, u_int8_t ttl)
{
struct recent_entry *e;
if (t->entries >= ip_list_tot) {
e = list_entry(t->lru_list.next, struct recent_entry, lru_list);
recent_entry_remove(t, e);
}
e = kmalloc(sizeof(*e) + sizeof(e->stamps[0]) * ip_pkt_list_tot,
GFP_ATOMIC);
if (e == NULL)
return NULL;
e->addr = addr;
e->ttl = ttl;
e->stamps[0] = jiffies;
e->nstamps = 1;
e->index = 1;
list_add_tail(&e->list, &t->iphash[recent_entry_hash(addr)]);
list_add_tail(&e->lru_list, &t->lru_list);
t->entries++;
return e;
}
static void recent_entry_update(struct recent_table *t, struct recent_entry *e)
{
e->stamps[e->index++] = jiffies;
if (e->index > e->nstamps)
e->nstamps = e->index;
e->index %= ip_pkt_list_tot;
list_move_tail(&e->lru_list, &t->lru_list);
}
static struct recent_table *recent_table_lookup(const char *name)
{
struct recent_table *t;
list_for_each_entry(t, &tables, list)
if (!strcmp(t->name, name))
return t;
return NULL;
}
static void recent_table_flush(struct recent_table *t)
{
struct recent_entry *e, *next;
unsigned int i;
for (i = 0; i < ip_list_hash_size; i++)
list_for_each_entry_safe(e, next, &t->iphash[i], list)
recent_entry_remove(t, e);
}
static bool
ipt_recent_match(const struct sk_buff *skb,
const struct net_device *in, const struct net_device *out,
const struct xt_match *match, const void *matchinfo,
int offset, unsigned int protoff, bool *hotdrop)
{
const struct ipt_recent_info *info = matchinfo;
struct recent_table *t;
struct recent_entry *e;
__be32 addr;
u_int8_t ttl;
bool ret = info->invert;
if (info->side == IPT_RECENT_DEST)
addr = ip_hdr(skb)->daddr;
else
addr = ip_hdr(skb)->saddr;
ttl = ip_hdr(skb)->ttl;
/* use TTL as seen before forwarding */
if (out && !skb->sk)
ttl++;
spin_lock_bh(&recent_lock);
t = recent_table_lookup(info->name);
e = recent_entry_lookup(t, addr,
info->check_set & IPT_RECENT_TTL ? ttl : 0);
if (e == NULL) {
if (!(info->check_set & IPT_RECENT_SET))
goto out;
e = recent_entry_init(t, addr, ttl);
if (e == NULL)
*hotdrop = true;
ret = !ret;
goto out;
}
if (info->check_set & IPT_RECENT_SET)
ret = !ret;
else if (info->check_set & IPT_RECENT_REMOVE) {
recent_entry_remove(t, e);
ret = !ret;
} else if (info->check_set & (IPT_RECENT_CHECK | IPT_RECENT_UPDATE)) {
unsigned long t = jiffies - info->seconds * HZ;
unsigned int i, hits = 0;
for (i = 0; i < e->nstamps; i++) {
if (info->seconds && time_after(t, e->stamps[i]))
continue;
if (++hits >= info->hit_count) {
ret = !ret;
break;
}
}
}
if (info->check_set & IPT_RECENT_SET ||
(info->check_set & IPT_RECENT_UPDATE && ret)) {
recent_entry_update(t, e);
e->ttl = ttl;
}
out:
spin_unlock_bh(&recent_lock);
return ret;
}
static bool
ipt_recent_checkentry(const char *tablename, const void *ip,
const struct xt_match *match, void *matchinfo,
unsigned int hook_mask)
{
const struct ipt_recent_info *info = matchinfo;
struct recent_table *t;
unsigned i;
bool ret = false;
if (hweight8(info->check_set &
(IPT_RECENT_SET | IPT_RECENT_REMOVE |
IPT_RECENT_CHECK | IPT_RECENT_UPDATE)) != 1)
return false;
if ((info->check_set & (IPT_RECENT_SET | IPT_RECENT_REMOVE)) &&
(info->seconds || info->hit_count))
return false;
if (info->name[0] == '\0' ||
strnlen(info->name, IPT_RECENT_NAME_LEN) == IPT_RECENT_NAME_LEN)
return false;
mutex_lock(&recent_mutex);
t = recent_table_lookup(info->name);
if (t != NULL) {
t->refcnt++;
ret = true;
goto out;
}
t = kzalloc(sizeof(*t) + sizeof(t->iphash[0]) * ip_list_hash_size,
GFP_KERNEL);
if (t == NULL)
goto out;
t->refcnt = 1;
strcpy(t->name, info->name);
INIT_LIST_HEAD(&t->lru_list);
for (i = 0; i < ip_list_hash_size; i++)
INIT_LIST_HEAD(&t->iphash[i]);
#ifdef CONFIG_PROC_FS
t->proc = create_proc_entry(t->name, ip_list_perms, proc_dir);
if (t->proc == NULL) {
kfree(t);
goto out;
}
t->proc->proc_fops = &recent_fops;
t->proc->uid = ip_list_uid;
t->proc->gid = ip_list_gid;
t->proc->data = t;
#endif
spin_lock_bh(&recent_lock);
list_add_tail(&t->list, &tables);
spin_unlock_bh(&recent_lock);
ret = true;
out:
mutex_unlock(&recent_mutex);
return ret;
}
static void
ipt_recent_destroy(const struct xt_match *match, void *matchinfo)
{
const struct ipt_recent_info *info = matchinfo;
struct recent_table *t;
mutex_lock(&recent_mutex);
t = recent_table_lookup(info->name);
if (--t->refcnt == 0) {
spin_lock_bh(&recent_lock);
list_del(&t->list);
spin_unlock_bh(&recent_lock);
recent_table_flush(t);
#ifdef CONFIG_PROC_FS
remove_proc_entry(t->name, proc_dir);
#endif
kfree(t);
}
mutex_unlock(&recent_mutex);
}
#ifdef CONFIG_PROC_FS
struct recent_iter_state {
struct recent_table *table;
unsigned int bucket;
};
static void *recent_seq_start(struct seq_file *seq, loff_t *pos)
{
struct recent_iter_state *st = seq->private;
const struct recent_table *t = st->table;
struct recent_entry *e;
loff_t p = *pos;
spin_lock_bh(&recent_lock);
for (st->bucket = 0; st->bucket < ip_list_hash_size; st->bucket++)
list_for_each_entry(e, &t->iphash[st->bucket], list)
if (p-- == 0)
return e;
return NULL;
}
static void *recent_seq_next(struct seq_file *seq, void *v, loff_t *pos)
{
struct recent_iter_state *st = seq->private;
struct recent_table *t = st->table;
struct recent_entry *e = v;
struct list_head *head = e->list.next;
while (head == &t->iphash[st->bucket]) {
if (++st->bucket >= ip_list_hash_size)
return NULL;
head = t->iphash[st->bucket].next;
}
(*pos)++;
return list_entry(head, struct recent_entry, list);
}
static void recent_seq_stop(struct seq_file *s, void *v)
{
spin_unlock_bh(&recent_lock);
}
static int recent_seq_show(struct seq_file *seq, void *v)
{
struct recent_entry *e = v;
unsigned int i;
i = (e->index - 1) % ip_pkt_list_tot;
seq_printf(seq, "src=%u.%u.%u.%u ttl: %u last_seen: %lu oldest_pkt: %u",
NIPQUAD(e->addr), e->ttl, e->stamps[i], e->index);
for (i = 0; i < e->nstamps; i++)
seq_printf(seq, "%s %lu", i ? "," : "", e->stamps[i]);
seq_printf(seq, "\n");
return 0;
}
static const struct seq_operations recent_seq_ops = {
.start = recent_seq_start,
.next = recent_seq_next,
.stop = recent_seq_stop,
.show = recent_seq_show,
};
static int recent_seq_open(struct inode *inode, struct file *file)
{
struct proc_dir_entry *pde = PDE(inode);
struct recent_iter_state *st;
st = __seq_open_private(file, &recent_seq_ops, sizeof(*st));
if (st == NULL)
return -ENOMEM;
st->table = pde->data;
return 0;
}
static ssize_t recent_proc_write(struct file *file, const char __user *input,
size_t size, loff_t *loff)
{
struct proc_dir_entry *pde = PDE(file->f_path.dentry->d_inode);
struct recent_table *t = pde->data;
struct recent_entry *e;
char buf[sizeof("+255.255.255.255")], *c = buf;
__be32 addr;
int add;
if (size > sizeof(buf))
size = sizeof(buf);
if (copy_from_user(buf, input, size))
return -EFAULT;
while (isspace(*c))
c++;
if (size - (c - buf) < 5)
return c - buf;
if (!strncmp(c, "clear", 5)) {
c += 5;
spin_lock_bh(&recent_lock);
recent_table_flush(t);
spin_unlock_bh(&recent_lock);
return c - buf;
}
switch (*c) {
case '-':
add = 0;
c++;
break;
case '+':
c++;
default:
add = 1;
break;
}
addr = in_aton(c);
spin_lock_bh(&recent_lock);
e = recent_entry_lookup(t, addr, 0);
if (e == NULL) {
if (add)
recent_entry_init(t, addr, 0);
} else {
if (add)
recent_entry_update(t, e);
else
recent_entry_remove(t, e);
}
spin_unlock_bh(&recent_lock);
return size;
}
static const struct file_operations recent_fops = {
.open = recent_seq_open,
.read = seq_read,
.write = recent_proc_write,
.release = seq_release_private,
.owner = THIS_MODULE,
};
#endif /* CONFIG_PROC_FS */
static struct xt_match recent_match __read_mostly = {
.name = "recent",
.family = AF_INET,
.match = ipt_recent_match,
.matchsize = sizeof(struct ipt_recent_info),
.checkentry = ipt_recent_checkentry,
.destroy = ipt_recent_destroy,
.me = THIS_MODULE,
};
static int __init ipt_recent_init(void)
{
int err;
if (!ip_list_tot || !ip_pkt_list_tot || ip_pkt_list_tot > 255)
return -EINVAL;
ip_list_hash_size = 1 << fls(ip_list_tot);
err = xt_register_match(&recent_match);
#ifdef CONFIG_PROC_FS
if (err)
return err;
proc_dir = proc_mkdir("ipt_recent", init_net.proc_net);
if (proc_dir == NULL) {
xt_unregister_match(&recent_match);
err = -ENOMEM;
}
#endif
return err;
}
static void __exit ipt_recent_exit(void)
{
BUG_ON(!list_empty(&tables));
xt_unregister_match(&recent_match);
#ifdef CONFIG_PROC_FS
remove_proc_entry("ipt_recent", init_net.proc_net);
#endif
}
module_init(ipt_recent_init);
module_exit(ipt_recent_exit);