[NETFILTER]: nf_conntrack: use extension infrastructure for helper

Signed-off-by: Yasuyuki Kozakai <yasuyuki.kozakai@toshiba.co.jp>
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

4 files changed, 88 insertions, 66 deletions

diff --git a/net/ipv4/netfilter/nf_nat_standalone.c b/net/ipv4/netfilter/nf_nat_standalone.c
index 55dac36dbc85..0b2f0c33f7cd 100644
--- a/net/ipv4/netfilter/nf_nat_standalone.c
+++ b/net/ipv4/netfilter/nf_nat_standalone.c
@@ -338,14 +338,6 @@ static int __init nf_nat_standalone_init(void)
                 return ret;
         }
 
-        size = ALIGN(size, __alignof__(struct nf_conn_help)) +
-               sizeof(struct nf_conn_help);
-        ret = nf_conntrack_register_cache(NF_CT_F_NAT|NF_CT_F_HELP,
-                                          "nf_nat:help", size);
-        if (ret < 0) {
-                printk(KERN_ERR "nf_nat_init: Unable to create slab cache\n");
-                goto cleanup_register_cache;
-        }
 #ifdef CONFIG_XFRM
         BUG_ON(ip_nat_decode_session != NULL);
         ip_nat_decode_session = nat_decode_session;
@@ -370,8 +362,6 @@ static int __init nf_nat_standalone_init(void)
         ip_nat_decode_session = NULL;
         synchronize_net();
 #endif
-        nf_conntrack_unregister_cache(NF_CT_F_NAT|NF_CT_F_HELP);
- cleanup_register_cache:
         nf_conntrack_unregister_cache(NF_CT_F_NAT);
         return ret;
 }
diff --git a/net/netfilter/nf_conntrack_core.c b/net/netfilter/nf_conntrack_core.c
index b56f954895bb..914506e6c787 100644
--- a/net/netfilter/nf_conntrack_core.c
+++ b/net/netfilter/nf_conntrack_core.c
@@ -566,7 +566,6 @@ __nf_conntrack_alloc(const struct nf_conntrack_tuple *orig,
                      u_int32_t features)
 {
         struct nf_conn *conntrack = NULL;
-        struct nf_conntrack_helper *helper;
 
         if (unlikely(!nf_conntrack_hash_rnd_initted)) {
                 get_random_bytes(&nf_conntrack_hash_rnd, 4);
@@ -593,14 +592,6 @@ __nf_conntrack_alloc(const struct nf_conntrack_tuple *orig,
         /*  find features needed by this conntrack. */
         features |= l3proto->get_features(orig);
 
-        /* FIXME: protect helper list per RCU */
-        read_lock_bh(&nf_conntrack_lock);
-        helper = __nf_ct_helper_find(repl);
-        /* NAT might want to assign a helper later */
-        if (helper || features & NF_CT_F_NAT)
-                features |= NF_CT_F_HELP;
-        read_unlock_bh(&nf_conntrack_lock);
-
         DEBUGP("nf_conntrack_alloc: features=0x%x\n", features);
 
         read_lock_bh(&nf_ct_cache_lock);
@@ -681,12 +672,6 @@ init_conntrack(const struct nf_conntrack_tuple *tuple,
                 return NULL;
         }
 
-        read_lock_bh(&nf_conntrack_lock);
-        exp = __nf_conntrack_expect_find(tuple);
-        if (exp && exp->helper)
-                features = NF_CT_F_HELP;
-        read_unlock_bh(&nf_conntrack_lock);
-
         conntrack = __nf_conntrack_alloc(tuple, &repl_tuple, l3proto, features);
         if (conntrack == NULL || IS_ERR(conntrack)) {
                 DEBUGP("Can't allocate conntrack.\n");
@@ -701,16 +686,21 @@ init_conntrack(const struct nf_conntrack_tuple *tuple,
 
         write_lock_bh(&nf_conntrack_lock);
         exp = find_expectation(tuple);
-
-        help = nfct_help(conntrack);
         if (exp) {
                 DEBUGP("conntrack: expectation arrives ct=%p exp=%p\n",
                         conntrack, exp);
                 /* Welcome, Mr. Bond.  We've been expecting you... */
                 __set_bit(IPS_EXPECTED_BIT, &conntrack->status);
                 conntrack->master = exp->master;
-                if (exp->helper)
-                        rcu_assign_pointer(help->helper, exp->helper);
+                if (exp->helper) {
+                        help = nf_ct_ext_add(conntrack, NF_CT_EXT_HELPER,
+                                             GFP_ATOMIC);
+                        if (help)
+                                rcu_assign_pointer(help->helper, exp->helper);
+                        else
+                                DEBUGP("failed to add helper extension area");
+                }
+
 #ifdef CONFIG_NF_CONNTRACK_MARK
                 conntrack->mark = exp->master->mark;
 #endif
@@ -720,10 +710,18 @@ init_conntrack(const struct nf_conntrack_tuple *tuple,
                 nf_conntrack_get(&conntrack->master->ct_general);
                 NF_CT_STAT_INC(expect_new);
         } else {
-                if (help) {
-                        /* not in hash table yet, so not strictly necessary */
-                        rcu_assign_pointer(help->helper,
-                                           __nf_ct_helper_find(&repl_tuple));
+                struct nf_conntrack_helper *helper;
+
+                helper = __nf_ct_helper_find(&repl_tuple);
+                if (helper) {
+                        help = nf_ct_ext_add(conntrack, NF_CT_EXT_HELPER,
+                                             GFP_ATOMIC);
+                        if (help)
+                                /* not in hash table yet, so not strictly
+                                   necessary */
+                                rcu_assign_pointer(help->helper, helper);
+                        else
+                                DEBUGP("failed to add helper extension area");
                 }
                 NF_CT_STAT_INC(new);
         }
@@ -892,6 +890,7 @@ void nf_conntrack_alter_reply(struct nf_conn *ct,
                               const struct nf_conntrack_tuple *newreply)
 {
         struct nf_conn_help *help = nfct_help(ct);
+        struct nf_conntrack_helper *helper;
 
         write_lock_bh(&nf_conntrack_lock);
         /* Should be unconfirmed, so not in hash table yet */
@@ -901,14 +900,28 @@ void nf_conntrack_alter_reply(struct nf_conn *ct,
         NF_CT_DUMP_TUPLE(newreply);
 
         ct->tuplehash[IP_CT_DIR_REPLY].tuple = *newreply;
-        if (!ct->master && help && help->expecting == 0) {
-                struct nf_conntrack_helper *helper;
-                helper = __nf_ct_helper_find(newreply);
-                if (helper)
-                        memset(&help->help, 0, sizeof(help->help));
-                /* not in hash table yet, so not strictly necessary */
-                rcu_assign_pointer(help->helper, helper);
+        if (ct->master || (help && help->expecting != 0))
+                goto out;
+
+        helper = __nf_ct_helper_find(newreply);
+        if (helper == NULL) {
+                if (help)
+                        rcu_assign_pointer(help->helper, NULL);
+                goto out;
         }
+
+        if (help == NULL) {
+                help = nf_ct_ext_add(ct, NF_CT_EXT_HELPER, GFP_ATOMIC);
+                if (help == NULL) {
+                        DEBUGP("failed to add helper extension area");
+                        goto out;
+                }
+        } else {
+                memset(&help->help, 0, sizeof(help->help));
+        }
+
+        rcu_assign_pointer(help->helper, helper);
+out:
         write_unlock_bh(&nf_conntrack_lock);
 }
 EXPORT_SYMBOL_GPL(nf_conntrack_alter_reply);
@@ -1150,6 +1163,7 @@ void nf_conntrack_cleanup(void)
                             nf_conntrack_htable_size);
 
         nf_conntrack_proto_fini();
+        nf_conntrack_helper_fini();
 }
 
 static struct list_head *alloc_hashtable(int size, int *vmalloced)
@@ -1272,6 +1286,10 @@ int __init nf_conntrack_init(void)
         if (ret < 0)
                 goto out_free_expect_slab;
 
+        ret = nf_conntrack_helper_init();
+        if (ret < 0)
+                goto out_fini_proto;
+
         /* For use by REJECT target */
         rcu_assign_pointer(ip_ct_attach, __nf_conntrack_attach);
         rcu_assign_pointer(nf_ct_destroy, destroy_conntrack);
@@ -1284,6 +1302,8 @@ int __init nf_conntrack_init(void)
 
         return ret;
 
+out_fini_proto:
+        nf_conntrack_proto_fini();
 out_free_expect_slab:
         kmem_cache_destroy(nf_conntrack_expect_cachep);
 err_free_conntrack_slab:
diff --git a/net/netfilter/nf_conntrack_helper.c b/net/netfilter/nf_conntrack_helper.c
index f868b7fbd9b4..6d32399d64e1 100644
--- a/net/netfilter/nf_conntrack_helper.c
+++ b/net/netfilter/nf_conntrack_helper.c
@@ -26,6 +26,7 @@
 #include <net/netfilter/nf_conntrack_l4proto.h>
 #include <net/netfilter/nf_conntrack_helper.h>
 #include <net/netfilter/nf_conntrack_core.h>
+#include <net/netfilter/nf_conntrack_extend.h>
 
 static __read_mostly LIST_HEAD(helpers);
 
@@ -100,18 +101,8 @@ static inline int unhelp(struct nf_conntrack_tuple_hash *i,
 
 int nf_conntrack_helper_register(struct nf_conntrack_helper *me)
 {
-        int size, ret;
-
         BUG_ON(me->timeout == 0);
 
-        size = ALIGN(sizeof(struct nf_conn), __alignof__(struct nf_conn_help)) +
-               sizeof(struct nf_conn_help);
-        ret = nf_conntrack_register_cache(NF_CT_F_HELP, "nf_conntrack:help",
-                                          size);
-        if (ret < 0) {
-                printk(KERN_ERR "nf_conntrack_helper_register: Unable to create slab cache for conntracks\n");
-                return ret;
-        }
         write_lock_bh(&nf_conntrack_lock);
         list_add(&me->list, &helpers);
         write_unlock_bh(&nf_conntrack_lock);
@@ -153,3 +144,19 @@ void nf_conntrack_helper_unregister(struct nf_conntrack_helper *me)
         synchronize_net();
 }
 EXPORT_SYMBOL_GPL(nf_conntrack_helper_unregister);
+
+struct nf_ct_ext_type helper_extend = {
+        .len    = sizeof(struct nf_conn_help),
+        .align  = __alignof__(struct nf_conn_help),
+        .id     = NF_CT_EXT_HELPER,
+};
+
+int nf_conntrack_helper_init()
+{
+        return nf_ct_extend_register(&helper_extend);
+}
+
+void nf_conntrack_helper_fini()
+{
+        nf_ct_extend_unregister(&helper_extend);
+}
diff --git a/net/netfilter/nf_conntrack_netlink.c b/net/netfilter/nf_conntrack_netlink.c
index d0fe3d769828..3d56f36074f7 100644
--- a/net/netfilter/nf_conntrack_netlink.c
+++ b/net/netfilter/nf_conntrack_netlink.c
@@ -856,23 +856,23 @@ ctnetlink_change_helper(struct nf_conn *ct, struct nfattr *cda[])
                 return 0;
         }
 
-        if (!help) {
-                /* FIXME: we need to reallocate and rehash */
-                return -EBUSY;
-        }
-
         helper = __nf_conntrack_helper_find_byname(helpname);
         if (helper == NULL)
                 return -EINVAL;
 
-        if (help->helper == helper)
-                return 0;
-
-        if (help->helper)
-                return -EBUSY;
+        if (help) {
+                if (help->helper == helper)
+                        return 0;
+                if (help->helper)
+                        return -EBUSY;
+                /* need to zero data of old helper */
+                memset(&help->help, 0, sizeof(help->help));
+        } else {
+                help = nf_ct_ext_add(ct, NF_CT_EXT_HELPER, GFP_KERNEL);
+                if (help == NULL)
+                        return -ENOMEM;
+        }
 
-        /* need to zero data of old helper */
-        memset(&help->help, 0, sizeof(help->help));
         rcu_assign_pointer(help->helper, helper);
 
         return 0;
@@ -957,7 +957,7 @@ ctnetlink_create_conntrack(struct nfattr *cda[],
         struct nf_conn *ct;
         int err = -EINVAL;
         struct nf_conn_help *help;
-        struct nf_conntrack_helper *helper = NULL;
+        struct nf_conntrack_helper *helper;
 
         ct = nf_conntrack_alloc(otuple, rtuple);
         if (ct == NULL || IS_ERR(ct))
@@ -987,9 +987,14 @@ ctnetlink_create_conntrack(struct nfattr *cda[],
                 ct->mark = ntohl(*(__be32 *)NFA_DATA(cda[CTA_MARK-1]));
 #endif
 
-        help = nfct_help(ct);
-        if (help) {
-                helper = nf_ct_helper_find_get(rtuple);
+        helper = nf_ct_helper_find_get(rtuple);
+        if (helper) {
+                help = nf_ct_ext_add(ct, NF_CT_EXT_HELPER, GFP_KERNEL);
+                if (help == NULL) {
+                        nf_ct_helper_put(helper);
+                        err = -ENOMEM;
+                        goto err;
+                }
                 /* not in hash table yet so not strictly necessary */
                 rcu_assign_pointer(help->helper, helper);
         }