blob: a5b5369c30f9e3ce88787818902c2227abfbe903 [file] [log] [blame]
/*
* xt_hashlimit - Netfilter module to limit the number of packets per time
* seperately for each hashbucket (sourceip/sourceport/dstip/dstport)
*
* (C) 2003-2004 by Harald Welte <laforge@netfilter.org>
* Copyright © CC Computer Consultants GmbH, 2007 - 2008
*
* Development of this code was funded by Astaro AG, http://www.astaro.com/
*/
#include <linux/module.h>
#include <linux/spinlock.h>
#include <linux/random.h>
#include <linux/jhash.h>
#include <linux/slab.h>
#include <linux/vmalloc.h>
#include <linux/proc_fs.h>
#include <linux/seq_file.h>
#include <linux/list.h>
#include <linux/skbuff.h>
#include <linux/mm.h>
#include <linux/in.h>
#include <linux/ip.h>
#if defined(CONFIG_IP6_NF_IPTABLES) || defined(CONFIG_IP6_NF_IPTABLES_MODULE)
#include <linux/ipv6.h>
#include <net/ipv6.h>
#endif
#include <net/net_namespace.h>
#include <linux/netfilter/x_tables.h>
#include <linux/netfilter_ipv4/ip_tables.h>
#include <linux/netfilter_ipv6/ip6_tables.h>
#include <linux/netfilter/xt_hashlimit.h>
#include <linux/mutex.h>
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Harald Welte <laforge@netfilter.org>");
MODULE_AUTHOR("Jan Engelhardt <jengelh@computergmbh.de>");
MODULE_DESCRIPTION("Xtables: per hash-bucket rate-limit match");
MODULE_ALIAS("ipt_hashlimit");
MODULE_ALIAS("ip6t_hashlimit");
/* need to declare this at the top */
static struct proc_dir_entry *hashlimit_procdir4;
static struct proc_dir_entry *hashlimit_procdir6;
static const struct file_operations dl_file_ops;
/* hash table crap */
struct dsthash_dst {
union {
struct {
__be32 src;
__be32 dst;
} ip;
#if defined(CONFIG_IP6_NF_IPTABLES) || defined(CONFIG_IP6_NF_IPTABLES_MODULE)
struct {
__be32 src[4];
__be32 dst[4];
} ip6;
#endif
};
__be16 src_port;
__be16 dst_port;
};
struct dsthash_ent {
/* static / read-only parts in the beginning */
struct hlist_node node;
struct dsthash_dst dst;
/* modified structure members in the end */
unsigned long expires; /* precalculated expiry time */
struct {
unsigned long prev; /* last modification */
u_int32_t credit;
u_int32_t credit_cap, cost;
} rateinfo;
};
struct xt_hashlimit_htable {
struct hlist_node node; /* global list of all htables */
atomic_t use;
u_int8_t family;
struct hashlimit_cfg1 cfg; /* config */
/* used internally */
spinlock_t lock; /* lock for list_head */
u_int32_t rnd; /* random seed for hash */
int rnd_initialized;
unsigned int count; /* number entries in table */
struct timer_list timer; /* timer for gc */
/* seq_file stuff */
struct proc_dir_entry *pde;
struct hlist_head hash[0]; /* hashtable itself */
};
static DEFINE_SPINLOCK(hashlimit_lock); /* protects htables list */
static DEFINE_MUTEX(hlimit_mutex); /* additional checkentry protection */
static HLIST_HEAD(hashlimit_htables);
static struct kmem_cache *hashlimit_cachep __read_mostly;
static inline bool dst_cmp(const struct dsthash_ent *ent,
const struct dsthash_dst *b)
{
return !memcmp(&ent->dst, b, sizeof(ent->dst));
}
static u_int32_t
hash_dst(const struct xt_hashlimit_htable *ht, const struct dsthash_dst *dst)
{
u_int32_t hash = jhash2((const u32 *)dst,
sizeof(*dst)/sizeof(u32),
ht->rnd);
/*
* Instead of returning hash % ht->cfg.size (implying a divide)
* we return the high 32 bits of the (hash * ht->cfg.size) that will
* give results between [0 and cfg.size-1] and same hash distribution,
* but using a multiply, less expensive than a divide
*/
return ((u64)hash * ht->cfg.size) >> 32;
}
static struct dsthash_ent *
dsthash_find(const struct xt_hashlimit_htable *ht,
const struct dsthash_dst *dst)
{
struct dsthash_ent *ent;
struct hlist_node *pos;
u_int32_t hash = hash_dst(ht, dst);
if (!hlist_empty(&ht->hash[hash])) {
hlist_for_each_entry(ent, pos, &ht->hash[hash], node)
if (dst_cmp(ent, dst))
return ent;
}
return NULL;
}
/* allocate dsthash_ent, initialize dst, put in htable and lock it */
static struct dsthash_ent *
dsthash_alloc_init(struct xt_hashlimit_htable *ht,
const struct dsthash_dst *dst)
{
struct dsthash_ent *ent;
/* initialize hash with random val at the time we allocate
* the first hashtable entry */
if (!ht->rnd_initialized) {
get_random_bytes(&ht->rnd, sizeof(ht->rnd));
ht->rnd_initialized = 1;
}
if (ht->cfg.max && ht->count >= ht->cfg.max) {
/* FIXME: do something. question is what.. */
if (net_ratelimit())
printk(KERN_WARNING
"xt_hashlimit: max count of %u reached\n",
ht->cfg.max);
return NULL;
}
ent = kmem_cache_alloc(hashlimit_cachep, GFP_ATOMIC);
if (!ent) {
if (net_ratelimit())
printk(KERN_ERR
"xt_hashlimit: can't allocate dsthash_ent\n");
return NULL;
}
memcpy(&ent->dst, dst, sizeof(ent->dst));
hlist_add_head(&ent->node, &ht->hash[hash_dst(ht, dst)]);
ht->count++;
return ent;
}
static inline void
dsthash_free(struct xt_hashlimit_htable *ht, struct dsthash_ent *ent)
{
hlist_del(&ent->node);
kmem_cache_free(hashlimit_cachep, ent);
ht->count--;
}
static void htable_gc(unsigned long htlong);
static int htable_create_v0(struct xt_hashlimit_info *minfo, u_int8_t family)
{
struct xt_hashlimit_htable *hinfo;
unsigned int size;
unsigned int i;
if (minfo->cfg.size)
size = minfo->cfg.size;
else {
size = ((num_physpages << PAGE_SHIFT) / 16384) /
sizeof(struct list_head);
if (num_physpages > (1024 * 1024 * 1024 / PAGE_SIZE))
size = 8192;
if (size < 16)
size = 16;
}
/* FIXME: don't use vmalloc() here or anywhere else -HW */
hinfo = vmalloc(sizeof(struct xt_hashlimit_htable) +
sizeof(struct list_head) * size);
if (!hinfo) {
printk(KERN_ERR "xt_hashlimit: unable to create hashtable\n");
return -1;
}
minfo->hinfo = hinfo;
/* copy match config into hashtable config */
hinfo->cfg.mode = minfo->cfg.mode;
hinfo->cfg.avg = minfo->cfg.avg;
hinfo->cfg.burst = minfo->cfg.burst;
hinfo->cfg.max = minfo->cfg.max;
hinfo->cfg.gc_interval = minfo->cfg.gc_interval;
hinfo->cfg.expire = minfo->cfg.expire;
if (family == NFPROTO_IPV4)
hinfo->cfg.srcmask = hinfo->cfg.dstmask = 32;
else
hinfo->cfg.srcmask = hinfo->cfg.dstmask = 128;
hinfo->cfg.size = size;
if (!hinfo->cfg.max)
hinfo->cfg.max = 8 * hinfo->cfg.size;
else if (hinfo->cfg.max < hinfo->cfg.size)
hinfo->cfg.max = hinfo->cfg.size;
for (i = 0; i < hinfo->cfg.size; i++)
INIT_HLIST_HEAD(&hinfo->hash[i]);
atomic_set(&hinfo->use, 1);
hinfo->count = 0;
hinfo->family = family;
hinfo->rnd_initialized = 0;
spin_lock_init(&hinfo->lock);
hinfo->pde = proc_create_data(minfo->name, 0,
(family == NFPROTO_IPV4) ?
hashlimit_procdir4 : hashlimit_procdir6,
&dl_file_ops, hinfo);
if (!hinfo->pde) {
vfree(hinfo);
return -1;
}
setup_timer(&hinfo->timer, htable_gc, (unsigned long )hinfo);
hinfo->timer.expires = jiffies + msecs_to_jiffies(hinfo->cfg.gc_interval);
add_timer(&hinfo->timer);
spin_lock_bh(&hashlimit_lock);
hlist_add_head(&hinfo->node, &hashlimit_htables);
spin_unlock_bh(&hashlimit_lock);
return 0;
}
static int htable_create(struct xt_hashlimit_mtinfo1 *minfo, u_int8_t family)
{
struct xt_hashlimit_htable *hinfo;
unsigned int size;
unsigned int i;
if (minfo->cfg.size) {
size = minfo->cfg.size;
} else {
size = (num_physpages << PAGE_SHIFT) / 16384 /
sizeof(struct list_head);
if (num_physpages > 1024 * 1024 * 1024 / PAGE_SIZE)
size = 8192;
if (size < 16)
size = 16;
}
/* FIXME: don't use vmalloc() here or anywhere else -HW */
hinfo = vmalloc(sizeof(struct xt_hashlimit_htable) +
sizeof(struct list_head) * size);
if (hinfo == NULL) {
printk(KERN_ERR "xt_hashlimit: unable to create hashtable\n");
return -1;
}
minfo->hinfo = hinfo;
/* copy match config into hashtable config */
memcpy(&hinfo->cfg, &minfo->cfg, sizeof(hinfo->cfg));
hinfo->cfg.size = size;
if (hinfo->cfg.max == 0)
hinfo->cfg.max = 8 * hinfo->cfg.size;
else if (hinfo->cfg.max < hinfo->cfg.size)
hinfo->cfg.max = hinfo->cfg.size;
for (i = 0; i < hinfo->cfg.size; i++)
INIT_HLIST_HEAD(&hinfo->hash[i]);
atomic_set(&hinfo->use, 1);
hinfo->count = 0;
hinfo->family = family;
hinfo->rnd_initialized = 0;
spin_lock_init(&hinfo->lock);
hinfo->pde = proc_create_data(minfo->name, 0,
(family == NFPROTO_IPV4) ?
hashlimit_procdir4 : hashlimit_procdir6,
&dl_file_ops, hinfo);
if (hinfo->pde == NULL) {
vfree(hinfo);
return -1;
}
setup_timer(&hinfo->timer, htable_gc, (unsigned long)hinfo);
hinfo->timer.expires = jiffies + msecs_to_jiffies(hinfo->cfg.gc_interval);
add_timer(&hinfo->timer);
spin_lock_bh(&hashlimit_lock);
hlist_add_head(&hinfo->node, &hashlimit_htables);
spin_unlock_bh(&hashlimit_lock);
return 0;
}
static bool select_all(const struct xt_hashlimit_htable *ht,
const struct dsthash_ent *he)
{
return 1;
}
static bool select_gc(const struct xt_hashlimit_htable *ht,
const struct dsthash_ent *he)
{
return time_after_eq(jiffies, he->expires);
}
static void htable_selective_cleanup(struct xt_hashlimit_htable *ht,
bool (*select)(const struct xt_hashlimit_htable *ht,
const struct dsthash_ent *he))
{
unsigned int i;
/* lock hash table and iterate over it */
spin_lock_bh(&ht->lock);
for (i = 0; i < ht->cfg.size; i++) {
struct dsthash_ent *dh;
struct hlist_node *pos, *n;
hlist_for_each_entry_safe(dh, pos, n, &ht->hash[i], node) {
if ((*select)(ht, dh))
dsthash_free(ht, dh);
}
}
spin_unlock_bh(&ht->lock);
}
/* hash table garbage collector, run by timer */
static void htable_gc(unsigned long htlong)
{
struct xt_hashlimit_htable *ht = (struct xt_hashlimit_htable *)htlong;
htable_selective_cleanup(ht, select_gc);
/* re-add the timer accordingly */
ht->timer.expires = jiffies + msecs_to_jiffies(ht->cfg.gc_interval);
add_timer(&ht->timer);
}
static void htable_destroy(struct xt_hashlimit_htable *hinfo)
{
del_timer_sync(&hinfo->timer);
/* remove proc entry */
remove_proc_entry(hinfo->pde->name,
hinfo->family == NFPROTO_IPV4 ? hashlimit_procdir4 :
hashlimit_procdir6);
htable_selective_cleanup(hinfo, select_all);
vfree(hinfo);
}
static struct xt_hashlimit_htable *htable_find_get(const char *name,
u_int8_t family)
{
struct xt_hashlimit_htable *hinfo;
struct hlist_node *pos;
spin_lock_bh(&hashlimit_lock);
hlist_for_each_entry(hinfo, pos, &hashlimit_htables, node) {
if (!strcmp(name, hinfo->pde->name) &&
hinfo->family == family) {
atomic_inc(&hinfo->use);
spin_unlock_bh(&hashlimit_lock);
return hinfo;
}
}
spin_unlock_bh(&hashlimit_lock);
return NULL;
}
static void htable_put(struct xt_hashlimit_htable *hinfo)
{
if (atomic_dec_and_test(&hinfo->use)) {
spin_lock_bh(&hashlimit_lock);
hlist_del(&hinfo->node);
spin_unlock_bh(&hashlimit_lock);
htable_destroy(hinfo);
}
}
/* The algorithm used is the Simple Token Bucket Filter (TBF)
* see net/sched/sch_tbf.c in the linux source tree
*/
/* Rusty: This is my (non-mathematically-inclined) understanding of
this algorithm. The `average rate' in jiffies becomes your initial
amount of credit `credit' and the most credit you can ever have
`credit_cap'. The `peak rate' becomes the cost of passing the
test, `cost'.
`prev' tracks the last packet hit: you gain one credit per jiffy.
If you get credit balance more than this, the extra credit is
discarded. Every time the match passes, you lose `cost' credits;
if you don't have that many, the test fails.
See Alexey's formal explanation in net/sched/sch_tbf.c.
To get the maximum range, we multiply by this factor (ie. you get N
credits per jiffy). We want to allow a rate as low as 1 per day
(slowest userspace tool allows), which means
CREDITS_PER_JIFFY*HZ*60*60*24 < 2^32 ie.
*/
#define MAX_CPJ (0xFFFFFFFF / (HZ*60*60*24))
/* Repeated shift and or gives us all 1s, final shift and add 1 gives
* us the power of 2 below the theoretical max, so GCC simply does a
* shift. */
#define _POW2_BELOW2(x) ((x)|((x)>>1))
#define _POW2_BELOW4(x) (_POW2_BELOW2(x)|_POW2_BELOW2((x)>>2))
#define _POW2_BELOW8(x) (_POW2_BELOW4(x)|_POW2_BELOW4((x)>>4))
#define _POW2_BELOW16(x) (_POW2_BELOW8(x)|_POW2_BELOW8((x)>>8))
#define _POW2_BELOW32(x) (_POW2_BELOW16(x)|_POW2_BELOW16((x)>>16))
#define POW2_BELOW32(x) ((_POW2_BELOW32(x)>>1) + 1)
#define CREDITS_PER_JIFFY POW2_BELOW32(MAX_CPJ)
/* Precision saver. */
static inline u_int32_t
user2credits(u_int32_t user)
{
/* If multiplying would overflow... */
if (user > 0xFFFFFFFF / (HZ*CREDITS_PER_JIFFY))
/* Divide first. */
return (user / XT_HASHLIMIT_SCALE) * HZ * CREDITS_PER_JIFFY;
return (user * HZ * CREDITS_PER_JIFFY) / XT_HASHLIMIT_SCALE;
}
static inline void rateinfo_recalc(struct dsthash_ent *dh, unsigned long now)
{
dh->rateinfo.credit += (now - dh->rateinfo.prev) * CREDITS_PER_JIFFY;
if (dh->rateinfo.credit > dh->rateinfo.credit_cap)
dh->rateinfo.credit = dh->rateinfo.credit_cap;
dh->rateinfo.prev = now;
}
static inline __be32 maskl(__be32 a, unsigned int l)
{
return l ? htonl(ntohl(a) & ~0 << (32 - l)) : 0;
}
#if defined(CONFIG_IP6_NF_IPTABLES) || defined(CONFIG_IP6_NF_IPTABLES_MODULE)
static void hashlimit_ipv6_mask(__be32 *i, unsigned int p)
{
switch (p) {
case 0 ... 31:
i[0] = maskl(i[0], p);
i[1] = i[2] = i[3] = 0;
break;
case 32 ... 63:
i[1] = maskl(i[1], p - 32);
i[2] = i[3] = 0;
break;
case 64 ... 95:
i[2] = maskl(i[2], p - 64);
i[3] = 0;
case 96 ... 127:
i[3] = maskl(i[3], p - 96);
break;
case 128:
break;
}
}
#endif
static int
hashlimit_init_dst(const struct xt_hashlimit_htable *hinfo,
struct dsthash_dst *dst,
const struct sk_buff *skb, unsigned int protoff)
{
__be16 _ports[2], *ports;
u8 nexthdr;
memset(dst, 0, sizeof(*dst));
switch (hinfo->family) {
case NFPROTO_IPV4:
if (hinfo->cfg.mode & XT_HASHLIMIT_HASH_DIP)
dst->ip.dst = maskl(ip_hdr(skb)->daddr,
hinfo->cfg.dstmask);
if (hinfo->cfg.mode & XT_HASHLIMIT_HASH_SIP)
dst->ip.src = maskl(ip_hdr(skb)->saddr,
hinfo->cfg.srcmask);
if (!(hinfo->cfg.mode &
(XT_HASHLIMIT_HASH_DPT | XT_HASHLIMIT_HASH_SPT)))
return 0;
nexthdr = ip_hdr(skb)->protocol;
break;
#if defined(CONFIG_IP6_NF_IPTABLES) || defined(CONFIG_IP6_NF_IPTABLES_MODULE)
case NFPROTO_IPV6:
if (hinfo->cfg.mode & XT_HASHLIMIT_HASH_DIP) {
memcpy(&dst->ip6.dst, &ipv6_hdr(skb)->daddr,
sizeof(dst->ip6.dst));
hashlimit_ipv6_mask(dst->ip6.dst, hinfo->cfg.dstmask);
}
if (hinfo->cfg.mode & XT_HASHLIMIT_HASH_SIP) {
memcpy(&dst->ip6.src, &ipv6_hdr(skb)->saddr,
sizeof(dst->ip6.src));
hashlimit_ipv6_mask(dst->ip6.src, hinfo->cfg.srcmask);
}
if (!(hinfo->cfg.mode &
(XT_HASHLIMIT_HASH_DPT | XT_HASHLIMIT_HASH_SPT)))
return 0;
nexthdr = ipv6_hdr(skb)->nexthdr;
protoff = ipv6_skip_exthdr(skb, sizeof(struct ipv6hdr), &nexthdr);
if ((int)protoff < 0)
return -1;
break;
#endif
default:
BUG();
return 0;
}
switch (nexthdr) {
case IPPROTO_TCP:
case IPPROTO_UDP:
case IPPROTO_UDPLITE:
case IPPROTO_SCTP:
case IPPROTO_DCCP:
ports = skb_header_pointer(skb, protoff, sizeof(_ports),
&_ports);
break;
default:
_ports[0] = _ports[1] = 0;
ports = _ports;
break;
}
if (!ports)
return -1;
if (hinfo->cfg.mode & XT_HASHLIMIT_HASH_SPT)
dst->src_port = ports[0];
if (hinfo->cfg.mode & XT_HASHLIMIT_HASH_DPT)
dst->dst_port = ports[1];
return 0;
}
static bool
hashlimit_mt_v0(const struct sk_buff *skb, const struct xt_match_param *par)
{
const struct xt_hashlimit_info *r = par->matchinfo;
struct xt_hashlimit_htable *hinfo = r->hinfo;
unsigned long now = jiffies;
struct dsthash_ent *dh;
struct dsthash_dst dst;
if (hashlimit_init_dst(hinfo, &dst, skb, par->thoff) < 0)
goto hotdrop;
spin_lock_bh(&hinfo->lock);
dh = dsthash_find(hinfo, &dst);
if (!dh) {
dh = dsthash_alloc_init(hinfo, &dst);
if (!dh) {
spin_unlock_bh(&hinfo->lock);
goto hotdrop;
}
dh->expires = jiffies + msecs_to_jiffies(hinfo->cfg.expire);
dh->rateinfo.prev = jiffies;
dh->rateinfo.credit = user2credits(hinfo->cfg.avg *
hinfo->cfg.burst);
dh->rateinfo.credit_cap = user2credits(hinfo->cfg.avg *
hinfo->cfg.burst);
dh->rateinfo.cost = user2credits(hinfo->cfg.avg);
} else {
/* update expiration timeout */
dh->expires = now + msecs_to_jiffies(hinfo->cfg.expire);
rateinfo_recalc(dh, now);
}
if (dh->rateinfo.credit >= dh->rateinfo.cost) {
/* We're underlimit. */
dh->rateinfo.credit -= dh->rateinfo.cost;
spin_unlock_bh(&hinfo->lock);
return true;
}
spin_unlock_bh(&hinfo->lock);
/* default case: we're overlimit, thus don't match */
return false;
hotdrop:
*par->hotdrop = true;
return false;
}
static bool
hashlimit_mt(const struct sk_buff *skb, const struct xt_match_param *par)
{
const struct xt_hashlimit_mtinfo1 *info = par->matchinfo;
struct xt_hashlimit_htable *hinfo = info->hinfo;
unsigned long now = jiffies;
struct dsthash_ent *dh;
struct dsthash_dst dst;
if (hashlimit_init_dst(hinfo, &dst, skb, par->thoff) < 0)
goto hotdrop;
spin_lock_bh(&hinfo->lock);
dh = dsthash_find(hinfo, &dst);
if (dh == NULL) {
dh = dsthash_alloc_init(hinfo, &dst);
if (dh == NULL) {
spin_unlock_bh(&hinfo->lock);
goto hotdrop;
}
dh->expires = jiffies + msecs_to_jiffies(hinfo->cfg.expire);
dh->rateinfo.prev = jiffies;
dh->rateinfo.credit = user2credits(hinfo->cfg.avg *
hinfo->cfg.burst);
dh->rateinfo.credit_cap = user2credits(hinfo->cfg.avg *
hinfo->cfg.burst);
dh->rateinfo.cost = user2credits(hinfo->cfg.avg);
} else {
/* update expiration timeout */
dh->expires = now + msecs_to_jiffies(hinfo->cfg.expire);
rateinfo_recalc(dh, now);
}
if (dh->rateinfo.credit >= dh->rateinfo.cost) {
/* below the limit */
dh->rateinfo.credit -= dh->rateinfo.cost;
spin_unlock_bh(&hinfo->lock);
return !(info->cfg.mode & XT_HASHLIMIT_INVERT);
}
spin_unlock_bh(&hinfo->lock);
/* default match is underlimit - so over the limit, we need to invert */
return info->cfg.mode & XT_HASHLIMIT_INVERT;
hotdrop:
*par->hotdrop = true;
return false;
}
static bool hashlimit_mt_check_v0(const struct xt_mtchk_param *par)
{
struct xt_hashlimit_info *r = par->matchinfo;
/* Check for overflow. */
if (r->cfg.burst == 0 ||
user2credits(r->cfg.avg * r->cfg.burst) < user2credits(r->cfg.avg)) {
printk(KERN_ERR "xt_hashlimit: overflow, try lower: %u/%u\n",
r->cfg.avg, r->cfg.burst);
return false;
}
if (r->cfg.mode == 0 ||
r->cfg.mode > (XT_HASHLIMIT_HASH_DPT |
XT_HASHLIMIT_HASH_DIP |
XT_HASHLIMIT_HASH_SIP |
XT_HASHLIMIT_HASH_SPT))
return false;
if (!r->cfg.gc_interval)
return false;
if (!r->cfg.expire)
return false;
if (r->name[sizeof(r->name) - 1] != '\0')
return false;
/* This is the best we've got: We cannot release and re-grab lock,
* since checkentry() is called before x_tables.c grabs xt_mutex.
* We also cannot grab the hashtable spinlock, since htable_create will
* call vmalloc, and that can sleep. And we cannot just re-search
* the list of htable's in htable_create(), since then we would
* create duplicate proc files. -HW */
mutex_lock(&hlimit_mutex);
r->hinfo = htable_find_get(r->name, par->match->family);
if (!r->hinfo && htable_create_v0(r, par->match->family) != 0) {
mutex_unlock(&hlimit_mutex);
return false;
}
mutex_unlock(&hlimit_mutex);
return true;
}
static bool hashlimit_mt_check(const struct xt_mtchk_param *par)
{
struct xt_hashlimit_mtinfo1 *info = par->matchinfo;
/* Check for overflow. */
if (info->cfg.burst == 0 ||
user2credits(info->cfg.avg * info->cfg.burst) <
user2credits(info->cfg.avg)) {
printk(KERN_ERR "xt_hashlimit: overflow, try lower: %u/%u\n",
info->cfg.avg, info->cfg.burst);
return false;
}
if (info->cfg.gc_interval == 0 || info->cfg.expire == 0)
return false;
if (info->name[sizeof(info->name)-1] != '\0')
return false;
if (par->match->family == NFPROTO_IPV4) {
if (info->cfg.srcmask > 32 || info->cfg.dstmask > 32)
return false;
} else {
if (info->cfg.srcmask > 128 || info->cfg.dstmask > 128)
return false;
}
/* This is the best we've got: We cannot release and re-grab lock,
* since checkentry() is called before x_tables.c grabs xt_mutex.
* We also cannot grab the hashtable spinlock, since htable_create will
* call vmalloc, and that can sleep. And we cannot just re-search
* the list of htable's in htable_create(), since then we would
* create duplicate proc files. -HW */
mutex_lock(&hlimit_mutex);
info->hinfo = htable_find_get(info->name, par->match->family);
if (!info->hinfo && htable_create(info, par->match->family) != 0) {
mutex_unlock(&hlimit_mutex);
return false;
}
mutex_unlock(&hlimit_mutex);
return true;
}
static void
hashlimit_mt_destroy_v0(const struct xt_mtdtor_param *par)
{
const struct xt_hashlimit_info *r = par->matchinfo;
htable_put(r->hinfo);
}
static void hashlimit_mt_destroy(const struct xt_mtdtor_param *par)
{
const struct xt_hashlimit_mtinfo1 *info = par->matchinfo;
htable_put(info->hinfo);
}
#ifdef CONFIG_COMPAT
struct compat_xt_hashlimit_info {
char name[IFNAMSIZ];
struct hashlimit_cfg cfg;
compat_uptr_t hinfo;
compat_uptr_t master;
};
static void hashlimit_mt_compat_from_user(void *dst, void *src)
{
int off = offsetof(struct compat_xt_hashlimit_info, hinfo);
memcpy(dst, src, off);
memset(dst + off, 0, sizeof(struct compat_xt_hashlimit_info) - off);
}
static int hashlimit_mt_compat_to_user(void __user *dst, void *src)
{
int off = offsetof(struct compat_xt_hashlimit_info, hinfo);
return copy_to_user(dst, src, off) ? -EFAULT : 0;
}
#endif
static struct xt_match hashlimit_mt_reg[] __read_mostly = {
{
.name = "hashlimit",
.revision = 0,
.family = NFPROTO_IPV4,
.match = hashlimit_mt_v0,
.matchsize = sizeof(struct xt_hashlimit_info),
#ifdef CONFIG_COMPAT
.compatsize = sizeof(struct compat_xt_hashlimit_info),
.compat_from_user = hashlimit_mt_compat_from_user,
.compat_to_user = hashlimit_mt_compat_to_user,
#endif
.checkentry = hashlimit_mt_check_v0,
.destroy = hashlimit_mt_destroy_v0,
.me = THIS_MODULE
},
{
.name = "hashlimit",
.revision = 1,
.family = NFPROTO_IPV4,
.match = hashlimit_mt,
.matchsize = sizeof(struct xt_hashlimit_mtinfo1),
.checkentry = hashlimit_mt_check,
.destroy = hashlimit_mt_destroy,
.me = THIS_MODULE,
},
#if defined(CONFIG_IP6_NF_IPTABLES) || defined(CONFIG_IP6_NF_IPTABLES_MODULE)
{
.name = "hashlimit",
.family = NFPROTO_IPV6,
.match = hashlimit_mt_v0,
.matchsize = sizeof(struct xt_hashlimit_info),
#ifdef CONFIG_COMPAT
.compatsize = sizeof(struct compat_xt_hashlimit_info),
.compat_from_user = hashlimit_mt_compat_from_user,
.compat_to_user = hashlimit_mt_compat_to_user,
#endif
.checkentry = hashlimit_mt_check_v0,
.destroy = hashlimit_mt_destroy_v0,
.me = THIS_MODULE
},
{
.name = "hashlimit",
.revision = 1,
.family = NFPROTO_IPV6,
.match = hashlimit_mt,
.matchsize = sizeof(struct xt_hashlimit_mtinfo1),
.checkentry = hashlimit_mt_check,
.destroy = hashlimit_mt_destroy,
.me = THIS_MODULE,
},
#endif
};
/* PROC stuff */
static void *dl_seq_start(struct seq_file *s, loff_t *pos)
__acquires(htable->lock)
{
struct proc_dir_entry *pde = s->private;
struct xt_hashlimit_htable *htable = pde->data;
unsigned int *bucket;
spin_lock_bh(&htable->lock);
if (*pos >= htable->cfg.size)
return NULL;
bucket = kmalloc(sizeof(unsigned int), GFP_ATOMIC);
if (!bucket)
return ERR_PTR(-ENOMEM);
*bucket = *pos;
return bucket;
}
static void *dl_seq_next(struct seq_file *s, void *v, loff_t *pos)
{
struct proc_dir_entry *pde = s->private;
struct xt_hashlimit_htable *htable = pde->data;
unsigned int *bucket = (unsigned int *)v;
*pos = ++(*bucket);
if (*pos >= htable->cfg.size) {
kfree(v);
return NULL;
}
return bucket;
}
static void dl_seq_stop(struct seq_file *s, void *v)
__releases(htable->lock)
{
struct proc_dir_entry *pde = s->private;
struct xt_hashlimit_htable *htable = pde->data;
unsigned int *bucket = (unsigned int *)v;
kfree(bucket);
spin_unlock_bh(&htable->lock);
}
static int dl_seq_real_show(struct dsthash_ent *ent, u_int8_t family,
struct seq_file *s)
{
/* recalculate to show accurate numbers */
rateinfo_recalc(ent, jiffies);
switch (family) {
case NFPROTO_IPV4:
return seq_printf(s, "%ld %pI4:%u->%pI4:%u %u %u %u\n",
(long)(ent->expires - jiffies)/HZ,
&ent->dst.ip.src,
ntohs(ent->dst.src_port),
&ent->dst.ip.dst,
ntohs(ent->dst.dst_port),
ent->rateinfo.credit, ent->rateinfo.credit_cap,
ent->rateinfo.cost);
#if defined(CONFIG_IP6_NF_IPTABLES) || defined(CONFIG_IP6_NF_IPTABLES_MODULE)
case NFPROTO_IPV6:
return seq_printf(s, "%ld %pI6:%u->%pI6:%u %u %u %u\n",
(long)(ent->expires - jiffies)/HZ,
&ent->dst.ip6.src,
ntohs(ent->dst.src_port),
&ent->dst.ip6.dst,
ntohs(ent->dst.dst_port),
ent->rateinfo.credit, ent->rateinfo.credit_cap,
ent->rateinfo.cost);
#endif
default:
BUG();
return 0;
}
}
static int dl_seq_show(struct seq_file *s, void *v)
{
struct proc_dir_entry *pde = s->private;
struct xt_hashlimit_htable *htable = pde->data;
unsigned int *bucket = (unsigned int *)v;
struct dsthash_ent *ent;
struct hlist_node *pos;
if (!hlist_empty(&htable->hash[*bucket])) {
hlist_for_each_entry(ent, pos, &htable->hash[*bucket], node)
if (dl_seq_real_show(ent, htable->family, s))
return 1;
}
return 0;
}
static const struct seq_operations dl_seq_ops = {
.start = dl_seq_start,
.next = dl_seq_next,
.stop = dl_seq_stop,
.show = dl_seq_show
};
static int dl_proc_open(struct inode *inode, struct file *file)
{
int ret = seq_open(file, &dl_seq_ops);
if (!ret) {
struct seq_file *sf = file->private_data;
sf->private = PDE(inode);
}
return ret;
}
static const struct file_operations dl_file_ops = {
.owner = THIS_MODULE,
.open = dl_proc_open,
.read = seq_read,
.llseek = seq_lseek,
.release = seq_release
};
static int __init hashlimit_mt_init(void)
{
int err;
err = xt_register_matches(hashlimit_mt_reg,
ARRAY_SIZE(hashlimit_mt_reg));
if (err < 0)
goto err1;
err = -ENOMEM;
hashlimit_cachep = kmem_cache_create("xt_hashlimit",
sizeof(struct dsthash_ent), 0, 0,
NULL);
if (!hashlimit_cachep) {
printk(KERN_ERR "xt_hashlimit: unable to create slab cache\n");
goto err2;
}
hashlimit_procdir4 = proc_mkdir("ipt_hashlimit", init_net.proc_net);
if (!hashlimit_procdir4) {
printk(KERN_ERR "xt_hashlimit: unable to create proc dir "
"entry\n");
goto err3;
}
err = 0;
#if defined(CONFIG_IP6_NF_IPTABLES) || defined(CONFIG_IP6_NF_IPTABLES_MODULE)
hashlimit_procdir6 = proc_mkdir("ip6t_hashlimit", init_net.proc_net);
if (!hashlimit_procdir6) {
printk(KERN_ERR "xt_hashlimit: unable to create proc dir "
"entry\n");
err = -ENOMEM;
}
#endif
if (!err)
return 0;
remove_proc_entry("ipt_hashlimit", init_net.proc_net);
err3:
kmem_cache_destroy(hashlimit_cachep);
err2:
xt_unregister_matches(hashlimit_mt_reg, ARRAY_SIZE(hashlimit_mt_reg));
err1:
return err;
}
static void __exit hashlimit_mt_exit(void)
{
remove_proc_entry("ipt_hashlimit", init_net.proc_net);
#if defined(CONFIG_IP6_NF_IPTABLES) || defined(CONFIG_IP6_NF_IPTABLES_MODULE)
remove_proc_entry("ip6t_hashlimit", init_net.proc_net);
#endif
kmem_cache_destroy(hashlimit_cachep);
xt_unregister_matches(hashlimit_mt_reg, ARRAY_SIZE(hashlimit_mt_reg));
}
module_init(hashlimit_mt_init);
module_exit(hashlimit_mt_exit);