[NETFILTER]: nf_conntrack_helper: use hashtable for conntrack helpers

Eliminate the last global list searched for every new connection.

Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 57 insertions, 13 deletions

diff --git a/net/netfilter/nf_conntrack_helper.c b/net/netfilter/nf_conntrack_helper.c
index 66c209d7e09d..b1179dd3d8c3 100644
--- a/net/netfilter/nf_conntrack_helper.c
+++ b/net/netfilter/nf_conntrack_helper.c
@@ -28,23 +28,41 @@
 #include <net/netfilter/nf_conntrack_core.h>
 #include <net/netfilter/nf_conntrack_extend.h>
 
-static __read_mostly LIST_HEAD(helpers);
+static struct hlist_head *nf_ct_helper_hash __read_mostly;
+static unsigned int nf_ct_helper_hsize __read_mostly;
+static unsigned int nf_ct_helper_count __read_mostly;
+static int nf_ct_helper_vmalloc;
+
+
+/* Stupid hash, but collision free for the default registrations of the
+ * helpers currently in the kernel. */
+static unsigned int helper_hash(const struct nf_conntrack_tuple *tuple)
+{
+        return (((tuple->src.l3num << 8) | tuple->dst.protonum) ^
+                tuple->src.u.all) % nf_ct_helper_hsize;
+}
 
 struct nf_conntrack_helper *
 __nf_ct_helper_find(const struct nf_conntrack_tuple *tuple)
 {
-        struct nf_conntrack_helper *h;
+        struct nf_conntrack_helper *helper;
         struct nf_conntrack_tuple_mask mask = { .src.u.all = htons(0xFFFF) };
+        struct hlist_node *n;
+        unsigned int h;
 
-        list_for_each_entry(h, &helpers, list) {
-                if (nf_ct_tuple_src_mask_cmp(tuple, &h->tuple, &mask))
-                        return h;
+        if (!nf_ct_helper_count)
+                return NULL;
+
+        h = helper_hash(tuple);
+        hlist_for_each_entry(helper, n, &nf_ct_helper_hash[h], hnode) {
+                if (nf_ct_tuple_src_mask_cmp(tuple, &helper->tuple, &mask))
+                        return helper;
         }
         return NULL;
 }
 
 struct nf_conntrack_helper *
-nf_ct_helper_find_get( const struct nf_conntrack_tuple *tuple)
+nf_ct_helper_find_get(const struct nf_conntrack_tuple *tuple)
 {
         struct nf_conntrack_helper *helper;
 
@@ -77,12 +95,15 @@ struct nf_conntrack_helper *
 __nf_conntrack_helper_find_byname(const char *name)
 {
         struct nf_conntrack_helper *h;
+        struct hlist_node *n;
+        unsigned int i;
 
-        list_for_each_entry(h, &helpers, list) {
-                if (!strcmp(h->name, name))
-                        return h;
+        for (i = 0; i < nf_ct_helper_hsize; i++) {
+                hlist_for_each_entry(h, n, &nf_ct_helper_hash[i], hnode) {
+                        if (!strcmp(h->name, name))
+                                return h;
+                }
         }
-
         return NULL;
 }
 EXPORT_SYMBOL_GPL(__nf_conntrack_helper_find_byname);
@@ -115,10 +136,13 @@ static inline int unhelp(struct nf_conntrack_tuple_hash *i,
 
 int nf_conntrack_helper_register(struct nf_conntrack_helper *me)
 {
+        unsigned int h = helper_hash(&me->tuple);
+
         BUG_ON(me->timeout == 0);
 
         write_lock_bh(&nf_conntrack_lock);
-        list_add(&me->list, &helpers);
+        hlist_add_head(&me->hnode, &nf_ct_helper_hash[h]);
+        nf_ct_helper_count++;
         write_unlock_bh(&nf_conntrack_lock);
 
         return 0;
@@ -134,7 +158,8 @@ void nf_conntrack_helper_unregister(struct nf_conntrack_helper *me)
 
         /* Need write lock here, to delete helper. */
         write_lock_bh(&nf_conntrack_lock);
-        list_del(&me->list);
+        hlist_del(&me->hnode);
+        nf_ct_helper_count--;
 
         /* Get rid of expectations */
         for (i = 0; i < nf_ct_expect_hsize; i++) {
@@ -171,10 +196,29 @@ static struct nf_ct_ext_type helper_extend __read_mostly = {
 
 int nf_conntrack_helper_init()
 {
-        return nf_ct_extend_register(&helper_extend);
+        int err;
+
+        nf_ct_helper_hsize = 1; /* gets rounded up to use one page */
+        nf_ct_helper_hash = nf_ct_alloc_hashtable(&nf_ct_helper_hsize,
+                                                  &nf_ct_helper_vmalloc);
+        if (!nf_ct_helper_hash)
+                return -ENOMEM;
+
+        err = nf_ct_extend_register(&helper_extend);
+        if (err < 0)
+                goto err1;
+
+        return 0;
+
+err1:
+        nf_ct_free_hashtable(nf_ct_helper_hash, nf_ct_helper_vmalloc,
+                             nf_ct_helper_hsize);
+        return err;
 }
 
 void nf_conntrack_helper_fini()
 {
         nf_ct_extend_unregister(&helper_extend);
+        nf_ct_free_hashtable(nf_ct_helper_hash, nf_ct_helper_vmalloc,
+                             nf_ct_helper_hsize);
 }