summaryrefslogtreecommitdiff
path: root/net/ipv4/netfilter/ipt_hashlimit.c
diff options
context:
space:
mode:
Diffstat (limited to 'net/ipv4/netfilter/ipt_hashlimit.c')
-rw-r--r--net/ipv4/netfilter/ipt_hashlimit.c731
1 files changed, 731 insertions, 0 deletions
diff --git a/net/ipv4/netfilter/ipt_hashlimit.c b/net/ipv4/netfilter/ipt_hashlimit.c
new file mode 100644
index 00000000000..f1937190cd7
--- /dev/null
+++ b/net/ipv4/netfilter/ipt_hashlimit.c
@@ -0,0 +1,731 @@
+/* iptables match extension to limit the number of packets per second
+ * seperately for each hashbucket (sourceip/sourceport/dstip/dstport)
+ *
+ * (C) 2003-2004 by Harald Welte <laforge@netfilter.org>
+ *
+ * $Id: ipt_hashlimit.c 3244 2004-10-20 16:24:29Z laforge@netfilter.org $
+ *
+ * Development of this code was funded by Astaro AG, http://www.astaro.com/
+ *
+ * based on ipt_limit.c by:
+ * Jérôme de Vivie <devivie@info.enserb.u-bordeaux.fr>
+ * Hervé Eychenne <eychenne@info.enserb.u-bordeaux.fr>
+ * Rusty Russell <rusty@rustcorp.com.au>
+ *
+ * The general idea is to create a hash table for every dstip and have a
+ * seperate limit counter per tuple. This way you can do something like 'limit
+ * the number of syn packets for each of my internal addresses.
+ *
+ * Ideally this would just be implemented as a general 'hash' match, which would
+ * allow us to attach any iptables target to it's hash buckets. But this is
+ * not possible in the current iptables architecture. As always, pkttables for
+ * 2.7.x will help ;)
+ */
+#include <linux/module.h>
+#include <linux/skbuff.h>
+#include <linux/spinlock.h>
+#include <linux/random.h>
+#include <linux/jhash.h>
+#include <linux/slab.h>
+#include <linux/vmalloc.h>
+#include <linux/tcp.h>
+#include <linux/udp.h>
+#include <linux/sctp.h>
+#include <linux/proc_fs.h>
+#include <linux/seq_file.h>
+#include <linux/list.h>
+
+#include <linux/netfilter_ipv4/ip_tables.h>
+#include <linux/netfilter_ipv4/ipt_hashlimit.h>
+#include <linux/netfilter_ipv4/lockhelp.h>
+
+/* FIXME: this is just for IP_NF_ASSERRT */
+#include <linux/netfilter_ipv4/ip_conntrack.h>
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Harald Welte <laforge@netfilter.org>");
+MODULE_DESCRIPTION("iptables match for limiting per hash-bucket");
+
+/* need to declare this at the top */
+static struct proc_dir_entry *hashlimit_procdir;
+static struct file_operations dl_file_ops;
+
+/* hash table crap */
+
+struct dsthash_dst {
+ u_int32_t src_ip;
+ u_int32_t dst_ip;
+ /* ports have to be consecutive !!! */
+ u_int16_t src_port;
+ u_int16_t 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 ipt_hashlimit_htable {
+ struct hlist_node node; /* global list of all htables */
+ atomic_t use;
+
+ struct hashlimit_cfg cfg; /* config */
+
+ /* used internally */
+ spinlock_t lock; /* lock for list_head */
+ u_int32_t rnd; /* random seed for hash */
+ struct timer_list timer; /* timer for gc */
+ atomic_t count; /* number entries in table */
+
+ /* seq_file stuff */
+ struct proc_dir_entry *pde;
+
+ struct hlist_head hash[0]; /* hashtable itself */
+};
+
+static DECLARE_LOCK(hashlimit_lock); /* protects htables list */
+static DECLARE_MUTEX(hlimit_mutex); /* additional checkentry protection */
+static HLIST_HEAD(hashlimit_htables);
+static kmem_cache_t *hashlimit_cachep;
+
+static inline int dst_cmp(const struct dsthash_ent *ent, struct dsthash_dst *b)
+{
+ return (ent->dst.dst_ip == b->dst_ip
+ && ent->dst.dst_port == b->dst_port
+ && ent->dst.src_port == b->src_port
+ && ent->dst.src_ip == b->src_ip);
+}
+
+static inline u_int32_t
+hash_dst(const struct ipt_hashlimit_htable *ht, const struct dsthash_dst *dst)
+{
+ return (jhash_3words(dst->dst_ip, (dst->dst_port<<16 | dst->src_port),
+ dst->src_ip, ht->rnd) % ht->cfg.size);
+}
+
+static inline struct dsthash_ent *
+__dsthash_find(const struct ipt_hashlimit_htable *ht, 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 ipt_hashlimit_htable *ht, 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)
+ get_random_bytes(&ht->rnd, 4);
+
+ if (ht->cfg.max &&
+ atomic_read(&ht->count) >= ht->cfg.max) {
+ /* FIXME: do something. question is what.. */
+ if (net_ratelimit())
+ printk(KERN_WARNING
+ "ipt_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
+ "ipt_hashlimit: can't allocate dsthash_ent\n");
+ return NULL;
+ }
+
+ atomic_inc(&ht->count);
+
+ ent->dst.dst_ip = dst->dst_ip;
+ ent->dst.dst_port = dst->dst_port;
+ ent->dst.src_ip = dst->src_ip;
+ ent->dst.src_port = dst->src_port;
+
+ hlist_add_head(&ent->node, &ht->hash[hash_dst(ht, dst)]);
+
+ return ent;
+}
+
+static inline void
+__dsthash_free(struct ipt_hashlimit_htable *ht, struct dsthash_ent *ent)
+{
+ hlist_del(&ent->node);
+ kmem_cache_free(hashlimit_cachep, ent);
+ atomic_dec(&ht->count);
+}
+static void htable_gc(unsigned long htlong);
+
+static int htable_create(struct ipt_hashlimit_info *minfo)
+{
+ int i;
+ unsigned int size;
+ struct ipt_hashlimit_htable *hinfo;
+
+ 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 ipt_hashlimit_htable)
+ + (sizeof(struct list_head) * size));
+ if (!hinfo) {
+ printk(KERN_ERR "ipt_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)
+ 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->count, 0);
+ atomic_set(&hinfo->use, 1);
+ hinfo->rnd = 0;
+ spin_lock_init(&hinfo->lock);
+ hinfo->pde = create_proc_entry(minfo->name, 0, hashlimit_procdir);
+ if (!hinfo->pde) {
+ vfree(hinfo);
+ return -1;
+ }
+ hinfo->pde->proc_fops = &dl_file_ops;
+ hinfo->pde->data = hinfo;
+
+ init_timer(&hinfo->timer);
+ hinfo->timer.expires = jiffies + msecs_to_jiffies(hinfo->cfg.gc_interval);
+ hinfo->timer.data = (unsigned long )hinfo;
+ hinfo->timer.function = htable_gc;
+ add_timer(&hinfo->timer);
+
+ LOCK_BH(&hashlimit_lock);
+ hlist_add_head(&hinfo->node, &hashlimit_htables);
+ UNLOCK_BH(&hashlimit_lock);
+
+ return 0;
+}
+
+static int select_all(struct ipt_hashlimit_htable *ht, struct dsthash_ent *he)
+{
+ return 1;
+}
+
+static int select_gc(struct ipt_hashlimit_htable *ht, struct dsthash_ent *he)
+{
+ return (jiffies >= he->expires);
+}
+
+static void htable_selective_cleanup(struct ipt_hashlimit_htable *ht,
+ int (*select)(struct ipt_hashlimit_htable *ht,
+ struct dsthash_ent *he))
+{
+ int i;
+
+ IP_NF_ASSERT(ht->cfg.size && ht->cfg.max);
+
+ /* 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 ipt_hashlimit_htable *ht = (struct ipt_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 ipt_hashlimit_htable *hinfo)
+{
+ /* remove timer, if it is pending */
+ if (timer_pending(&hinfo->timer))
+ del_timer(&hinfo->timer);
+
+ /* remove proc entry */
+ remove_proc_entry(hinfo->pde->name, hashlimit_procdir);
+
+ htable_selective_cleanup(hinfo, select_all);
+ vfree(hinfo);
+}
+
+static struct ipt_hashlimit_htable *htable_find_get(char *name)
+{
+ struct ipt_hashlimit_htable *hinfo;
+ struct hlist_node *pos;
+
+ LOCK_BH(&hashlimit_lock);
+ hlist_for_each_entry(hinfo, pos, &hashlimit_htables, node) {
+ if (!strcmp(name, hinfo->pde->name)) {
+ atomic_inc(&hinfo->use);
+ UNLOCK_BH(&hashlimit_lock);
+ return hinfo;
+ }
+ }
+ UNLOCK_BH(&hashlimit_lock);
+
+ return NULL;
+}
+
+static void htable_put(struct ipt_hashlimit_htable *hinfo)
+{
+ if (atomic_dec_and_test(&hinfo->use)) {
+ LOCK_BH(&hashlimit_lock);
+ hlist_del(&hinfo->node);
+ 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 / IPT_HASHLIMIT_SCALE) * HZ * CREDITS_PER_JIFFY;
+
+ return (user * HZ * CREDITS_PER_JIFFY) / IPT_HASHLIMIT_SCALE;
+}
+
+static inline void rateinfo_recalc(struct dsthash_ent *dh, unsigned long now)
+{
+ dh->rateinfo.credit += (now - xchg(&dh->rateinfo.prev, now))
+ * CREDITS_PER_JIFFY;
+ if (dh->rateinfo.credit > dh->rateinfo.credit_cap)
+ dh->rateinfo.credit = dh->rateinfo.credit_cap;
+}
+
+static inline int get_ports(const struct sk_buff *skb, int offset,
+ u16 ports[2])
+{
+ union {
+ struct tcphdr th;
+ struct udphdr uh;
+ sctp_sctphdr_t sctph;
+ } hdr_u, *ptr_u;
+
+ /* Must not be a fragment. */
+ if (offset)
+ return 1;
+
+ /* Must be big enough to read ports (both UDP and TCP have
+ them at the start). */
+ ptr_u = skb_header_pointer(skb, skb->nh.iph->ihl*4, 8, &hdr_u);
+ if (!ptr_u)
+ return 1;
+
+ switch (skb->nh.iph->protocol) {
+ case IPPROTO_TCP:
+ ports[0] = ptr_u->th.source;
+ ports[1] = ptr_u->th.dest;
+ break;
+ case IPPROTO_UDP:
+ ports[0] = ptr_u->uh.source;
+ ports[1] = ptr_u->uh.dest;
+ break;
+ case IPPROTO_SCTP:
+ ports[0] = ptr_u->sctph.source;
+ ports[1] = ptr_u->sctph.dest;
+ break;
+ default:
+ /* all other protocols don't supprot per-port hash
+ * buckets */
+ ports[0] = ports[1] = 0;
+ break;
+ }
+
+ return 0;
+}
+
+
+static int
+hashlimit_match(const struct sk_buff *skb,
+ const struct net_device *in,
+ const struct net_device *out,
+ const void *matchinfo,
+ int offset,
+ int *hotdrop)
+{
+ struct ipt_hashlimit_info *r =
+ ((struct ipt_hashlimit_info *)matchinfo)->u.master;
+ struct ipt_hashlimit_htable *hinfo = r->hinfo;
+ unsigned long now = jiffies;
+ struct dsthash_ent *dh;
+ struct dsthash_dst dst;
+
+ /* build 'dst' according to hinfo->cfg and current packet */
+ memset(&dst, 0, sizeof(dst));
+ if (hinfo->cfg.mode & IPT_HASHLIMIT_HASH_DIP)
+ dst.dst_ip = skb->nh.iph->daddr;
+ if (hinfo->cfg.mode & IPT_HASHLIMIT_HASH_SIP)
+ dst.src_ip = skb->nh.iph->saddr;
+ if (hinfo->cfg.mode & IPT_HASHLIMIT_HASH_DPT
+ ||hinfo->cfg.mode & IPT_HASHLIMIT_HASH_SPT) {
+ u_int16_t ports[2];
+ if (get_ports(skb, offset, ports)) {
+ /* We've been asked to examine this packet, and we
+ can't. Hence, no choice but to drop. */
+ *hotdrop = 1;
+ return 0;
+ }
+ if (hinfo->cfg.mode & IPT_HASHLIMIT_HASH_SPT)
+ dst.src_port = ports[0];
+ if (hinfo->cfg.mode & IPT_HASHLIMIT_HASH_DPT)
+ dst.dst_port = ports[1];
+ }
+
+ spin_lock_bh(&hinfo->lock);
+ dh = __dsthash_find(hinfo, &dst);
+ if (!dh) {
+ dh = __dsthash_alloc_init(hinfo, &dst);
+
+ if (!dh) {
+ /* enomem... don't match == DROP */
+ if (net_ratelimit())
+ printk(KERN_ERR "%s: ENOMEM\n", __FUNCTION__);
+ spin_unlock_bh(&hinfo->lock);
+ return 0;
+ }
+
+ 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);
+
+ spin_unlock_bh(&hinfo->lock);
+ return 1;
+ }
+
+ /* 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 1;
+ }
+
+ spin_unlock_bh(&hinfo->lock);
+
+ /* default case: we're overlimit, thus don't match */
+ return 0;
+}
+
+static int
+hashlimit_checkentry(const char *tablename,
+ const struct ipt_ip *ip,
+ void *matchinfo,
+ unsigned int matchsize,
+ unsigned int hook_mask)
+{
+ struct ipt_hashlimit_info *r = matchinfo;
+
+ if (matchsize != IPT_ALIGN(sizeof(struct ipt_hashlimit_info)))
+ return 0;
+
+ /* Check for overflow. */
+ if (r->cfg.burst == 0
+ || user2credits(r->cfg.avg * r->cfg.burst) <
+ user2credits(r->cfg.avg)) {
+ printk(KERN_ERR "ipt_hashlimit: Overflow, try lower: %u/%u\n",
+ r->cfg.avg, r->cfg.burst);
+ return 0;
+ }
+
+ if (r->cfg.mode == 0
+ || r->cfg.mode > (IPT_HASHLIMIT_HASH_DPT
+ |IPT_HASHLIMIT_HASH_DIP
+ |IPT_HASHLIMIT_HASH_SIP
+ |IPT_HASHLIMIT_HASH_SPT))
+ return 0;
+
+ if (!r->cfg.gc_interval)
+ return 0;
+
+ if (!r->cfg.expire)
+ return 0;
+
+ /* This is the best we've got: We cannot release and re-grab lock,
+ * since checkentry() is called before ip_tables.c grabs ipt_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 */
+ down(&hlimit_mutex);
+ r->hinfo = htable_find_get(r->name);
+ if (!r->hinfo && (htable_create(r) != 0)) {
+ up(&hlimit_mutex);
+ return 0;
+ }
+ up(&hlimit_mutex);
+
+ /* Ugly hack: For SMP, we only want to use one set */
+ r->u.master = r;
+
+ return 1;
+}
+
+static void
+hashlimit_destroy(void *matchinfo, unsigned int matchsize)
+{
+ struct ipt_hashlimit_info *r = (struct ipt_hashlimit_info *) matchinfo;
+
+ htable_put(r->hinfo);
+}
+
+static struct ipt_match ipt_hashlimit = {
+ .name = "hashlimit",
+ .match = hashlimit_match,
+ .checkentry = hashlimit_checkentry,
+ .destroy = hashlimit_destroy,
+ .me = THIS_MODULE
+};
+
+/* PROC stuff */
+
+static void *dl_seq_start(struct seq_file *s, loff_t *pos)
+{
+ struct proc_dir_entry *pde = s->private;
+ struct ipt_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 ipt_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)
+{
+ struct proc_dir_entry *pde = s->private;
+ struct ipt_hashlimit_htable *htable = pde->data;
+ unsigned int *bucket = (unsigned int *)v;
+
+ kfree(bucket);
+
+ spin_unlock_bh(&htable->lock);
+}
+
+static inline int dl_seq_real_show(struct dsthash_ent *ent, struct seq_file *s)
+{
+ /* recalculate to show accurate numbers */
+ rateinfo_recalc(ent, jiffies);
+
+ return seq_printf(s, "%ld %u.%u.%u.%u:%u->%u.%u.%u.%u:%u %u %u %u\n",
+ (long)(ent->expires - jiffies)/HZ,
+ NIPQUAD(ent->dst.src_ip), ntohs(ent->dst.src_port),
+ NIPQUAD(ent->dst.dst_ip), ntohs(ent->dst.dst_port),
+ ent->rateinfo.credit, ent->rateinfo.credit_cap,
+ ent->rateinfo.cost);
+}
+
+static int dl_seq_show(struct seq_file *s, void *v)
+{
+ struct proc_dir_entry *pde = s->private;
+ struct ipt_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, s)) {
+ /* buffer was filled and unable to print that tuple */
+ return 1;
+ }
+ }
+
+ return 0;
+}
+
+static 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 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_or_fini(int fini)
+{
+ int ret = 0;
+
+ if (fini)
+ goto cleanup;
+
+ if (ipt_register_match(&ipt_hashlimit)) {
+ ret = -EINVAL;
+ goto cleanup_nothing;
+ }
+
+ hashlimit_cachep = kmem_cache_create("ipt_hashlimit",
+ sizeof(struct dsthash_ent), 0,
+ 0, NULL, NULL);
+ if (!hashlimit_cachep) {
+ printk(KERN_ERR "Unable to create ipt_hashlimit slab cache\n");
+ ret = -ENOMEM;
+ goto cleanup_unreg_match;
+ }
+
+ hashlimit_procdir = proc_mkdir("ipt_hashlimit", proc_net);
+ if (!hashlimit_procdir) {
+ printk(KERN_ERR "Unable to create proc dir entry\n");
+ ret = -ENOMEM;
+ goto cleanup_free_slab;
+ }
+
+ return ret;
+
+cleanup:
+ remove_proc_entry("ipt_hashlimit", proc_net);
+cleanup_free_slab:
+ kmem_cache_destroy(hashlimit_cachep);
+cleanup_unreg_match:
+ ipt_unregister_match(&ipt_hashlimit);
+cleanup_nothing:
+ return ret;
+
+}
+
+static int __init init(void)
+{
+ return init_or_fini(0);
+}
+
+static void __exit fini(void)
+{
+ init_or_fini(1);
+}
+
+module_init(init);
+module_exit(fini);