netfilter: ctnetlink: fix expectation mask dump
[linux-2.6.git] / net / netfilter / nf_conntrack_helper.c
index cc8ae74..65c2a7b 100644 (file)
@@ -20,6 +20,8 @@
 #include <linux/err.h>
 #include <linux/kernel.h>
 #include <linux/netdevice.h>
+#include <linux/rculist.h>
+#include <linux/rtnetlink.h>
 
 #include <net/netfilter/nf_conntrack.h>
 #include <net/netfilter/nf_conntrack_l3proto.h>
 #include <net/netfilter/nf_conntrack_core.h>
 #include <net/netfilter/nf_conntrack_extend.h>
 
-static __read_mostly LIST_HEAD(helpers);
+static DEFINE_MUTEX(nf_ct_helper_mutex);
+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;
 
-struct nf_conntrack_helper *
+
+/* 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) ^
+               (__force __u16)tuple->src.u.all) % nf_ct_helper_hsize;
+}
+
+static 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_rcu(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_conntrack_helper_find_byname(const char *name)
 {
-       struct nf_conntrack_helper *helper;
+       struct nf_conntrack_helper *h;
+       struct hlist_node *n;
+       unsigned int i;
 
-       /* need nf_conntrack_lock to assure that helper exists until
-        * try_module_get() is called */
-       read_lock_bh(&nf_conntrack_lock);
-
-       helper = __nf_ct_helper_find(tuple);
-       if (helper) {
-               /* need to increase module usage count to assure helper will
-                * not go away while the caller is e.g. busy putting a
-                * conntrack in the hash that uses the helper */
-               if (!try_module_get(helper->me))
-                       helper = NULL;
+       for (i = 0; i < nf_ct_helper_hsize; i++) {
+               hlist_for_each_entry_rcu(h, n, &nf_ct_helper_hash[i], hnode) {
+                       if (!strcmp(h->name, name))
+                               return h;
+               }
        }
-
-       read_unlock_bh(&nf_conntrack_lock);
-
-       return helper;
+       return NULL;
 }
-EXPORT_SYMBOL_GPL(nf_ct_helper_find_get);
+EXPORT_SYMBOL_GPL(__nf_conntrack_helper_find_byname);
 
-void nf_ct_helper_put(struct nf_conntrack_helper *helper)
+struct nf_conn_help *nf_ct_helper_ext_add(struct nf_conn *ct, gfp_t gfp)
 {
-       module_put(helper->me);
+       struct nf_conn_help *help;
+
+       help = nf_ct_ext_add(ct, NF_CT_EXT_HELPER, gfp);
+       if (help)
+               INIT_HLIST_HEAD(&help->expectations);
+       else
+               pr_debug("failed to add helper extension area");
+       return help;
 }
-EXPORT_SYMBOL_GPL(nf_ct_helper_put);
+EXPORT_SYMBOL_GPL(nf_ct_helper_ext_add);
 
-struct nf_conntrack_helper *
-__nf_conntrack_helper_find_byname(const char *name)
+int __nf_ct_try_assign_helper(struct nf_conn *ct, gfp_t flags)
 {
-       struct nf_conntrack_helper *h;
+       int ret = 0;
+       struct nf_conntrack_helper *helper;
+       struct nf_conn_help *help = nfct_help(ct);
 
-       list_for_each_entry(h, &helpers, list) {
-               if (!strcmp(h->name, name))
-                       return h;
+       helper = __nf_ct_helper_find(&ct->tuplehash[IP_CT_DIR_REPLY].tuple);
+       if (helper == NULL) {
+               if (help)
+                       rcu_assign_pointer(help->helper, NULL);
+               goto out;
        }
 
-       return NULL;
+       if (help == NULL) {
+               help = nf_ct_helper_ext_add(ct, flags);
+               if (help == NULL) {
+                       ret = -ENOMEM;
+                       goto out;
+               }
+       } else {
+               memset(&help->help, 0, sizeof(help->help));
+       }
+
+       rcu_assign_pointer(help->helper, helper);
+out:
+       return ret;
 }
-EXPORT_SYMBOL_GPL(__nf_conntrack_helper_find_byname);
+EXPORT_SYMBOL_GPL(__nf_ct_try_assign_helper);
 
 static inline int unhelp(struct nf_conntrack_tuple_hash *i,
                         const struct nf_conntrack_helper *me)
@@ -100,33 +136,50 @@ static inline int unhelp(struct nf_conntrack_tuple_hash *i,
        return 0;
 }
 
+void nf_ct_helper_destroy(struct nf_conn *ct)
+{
+       struct nf_conn_help *help = nfct_help(ct);
+       struct nf_conntrack_helper *helper;
+
+       if (help) {
+               rcu_read_lock();
+               helper = rcu_dereference(help->helper);
+               if (helper && helper->destroy)
+                       helper->destroy(ct);
+               rcu_read_unlock();
+       }
+}
+
 int nf_conntrack_helper_register(struct nf_conntrack_helper *me)
 {
-       BUG_ON(me->timeout == 0);
+       unsigned int h = helper_hash(&me->tuple);
+
+       BUG_ON(me->expect_policy == NULL);
+       BUG_ON(me->expect_class_max >= NF_CT_MAX_EXPECT_CLASSES);
+       BUG_ON(strlen(me->name) > NF_CT_HELPER_NAME_LEN - 1);
 
-       write_lock_bh(&nf_conntrack_lock);
-       list_add(&me->list, &helpers);
-       write_unlock_bh(&nf_conntrack_lock);
+       mutex_lock(&nf_ct_helper_mutex);
+       hlist_add_head_rcu(&me->hnode, &nf_ct_helper_hash[h]);
+       nf_ct_helper_count++;
+       mutex_unlock(&nf_ct_helper_mutex);
 
        return 0;
 }
 EXPORT_SYMBOL_GPL(nf_conntrack_helper_register);
 
-void nf_conntrack_helper_unregister(struct nf_conntrack_helper *me)
+static void __nf_conntrack_helper_unregister(struct nf_conntrack_helper *me,
+                                            struct net *net)
 {
        struct nf_conntrack_tuple_hash *h;
        struct nf_conntrack_expect *exp;
-       struct hlist_node *n, *next;
+       const struct hlist_node *n, *next;
+       const struct hlist_nulls_node *nn;
        unsigned int i;
 
-       /* Need write lock here, to delete helper. */
-       write_lock_bh(&nf_conntrack_lock);
-       list_del(&me->list);
-
        /* Get rid of expectations */
        for (i = 0; i < nf_ct_expect_hsize; i++) {
                hlist_for_each_entry_safe(exp, n, next,
-                                         &nf_ct_expect_hash[i], hnode) {
+                                         &net->ct.expect_hash[i], hnode) {
                        struct nf_conn_help *help = nfct_help(exp->master);
                        if ((help->helper == me || exp->helper == me) &&
                            del_timer(&exp->timeout)) {
@@ -137,16 +190,34 @@ void nf_conntrack_helper_unregister(struct nf_conntrack_helper *me)
        }
 
        /* Get rid of expecteds, set helpers to NULL. */
-       hlist_for_each_entry(h, n, &unconfirmed, hnode)
+       hlist_nulls_for_each_entry(h, nn, &net->ct.unconfirmed, hnnode)
                unhelp(h, me);
        for (i = 0; i < nf_conntrack_htable_size; i++) {
-               hlist_for_each_entry(h, n, &nf_conntrack_hash[i], hnode)
+               hlist_nulls_for_each_entry(h, nn, &net->ct.hash[i], hnnode)
                        unhelp(h, me);
        }
-       write_unlock_bh(&nf_conntrack_lock);
+}
+
+void nf_conntrack_helper_unregister(struct nf_conntrack_helper *me)
+{
+       struct net *net;
+
+       mutex_lock(&nf_ct_helper_mutex);
+       hlist_del_rcu(&me->hnode);
+       nf_ct_helper_count--;
+       mutex_unlock(&nf_ct_helper_mutex);
 
-       /* Someone could be still looking at the helper in a bh. */
-       synchronize_net();
+       /* Make sure every nothing is still using the helper unless its a
+        * connection in the hash.
+        */
+       synchronize_rcu();
+
+       rtnl_lock();
+       spin_lock_bh(&nf_conntrack_lock);
+       for_each_net(net)
+               __nf_conntrack_helper_unregister(me, net);
+       spin_unlock_bh(&nf_conntrack_lock);
+       rtnl_unlock();
 }
 EXPORT_SYMBOL_GPL(nf_conntrack_helper_unregister);
 
@@ -156,12 +227,31 @@ static struct nf_ct_ext_type helper_extend __read_mostly = {
        .id     = NF_CT_EXT_HELPER,
 };
 
-int nf_conntrack_helper_init()
+int nf_conntrack_helper_init(void)
 {
-       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, 0);
+       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()
+void nf_conntrack_helper_fini(void)
 {
        nf_ct_extend_unregister(&helper_extend);
+       nf_ct_free_hashtable(nf_ct_helper_hash, nf_ct_helper_vmalloc,
+                            nf_ct_helper_hsize);
 }