netfilter: conntrack: remove prealloc support

It was used by the nat extension, but since commit
7c9664351980 ("netfilter: move nat hlist_head to nf_conn") its only needed
for connections that use MASQUERADE target or a nat helper.

Also it seems a lot easier to preallocate a fixed size instead.

With default settings, conntrack first adds ecache extension (sysctl
defaults to 1), so we get 40(ct extension header) + 24 (ecache) == 64 byte
on x86_64 for initial allocation.

Followup patches can constify the extension structs and avoid
the initial zeroing of the entire extension area.

Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

diff --git a/include/net/netfilter/nf_conntrack_extend.h b/include/net/netfilter/nf_conntrack_extend.h
index 5fc908dc9f3281a2f5ea755a5448747cce70a7c9..dd776bf9e2fa06a0ab0e87598cb2b610a58e0253 100644 (file)
--- a/include/net/netfilter/nf_conntrack_extend.h
+++ b/include/net/netfilter/nf_conntrack_extend.h
@@ -88,21 +88,15 @@ static inline void nf_ct_ext_free(struct nf_conn *ct)
 /* Add this type, returns pointer to data or NULL. */
 void *nf_ct_ext_add(struct nf_conn *ct, enum nf_ct_ext_id id, gfp_t gfp);
 
-#define NF_CT_EXT_F_PREALLOC   0x0001
-
 struct nf_ct_ext_type {
        /* Destroys relationships (can be NULL). */
        void (*destroy)(struct nf_conn *ct);
 
        enum nf_ct_ext_id id;
 
-       unsigned int flags;
-
        /* Length and min alignment. */
        u8 len;
        u8 align;
-       /* initial size of nf_ct_ext. */
-       u8 alloc_size;
 };
 
 int nf_ct_extend_register(struct nf_ct_ext_type *type);

diff --git a/net/netfilter/nf_conntrack_extend.c b/net/netfilter/nf_conntrack_extend.c
index b5879a9c748d0c392234312152455bafef1ed92a..2e4b41bc67a0fb2d1fa79c7d0a3dc90ef384011f 100644 (file)
--- a/net/netfilter/nf_conntrack_extend.c
+++ b/net/netfilter/nf_conntrack_extend.c
@@ -18,6 +18,7 @@
 
 static struct nf_ct_ext_type __rcu *nf_ct_ext_types[NF_CT_EXT_NUM];
 static DEFINE_MUTEX(nf_ct_ext_type_mutex);
+#define NF_CT_EXT_PREALLOC     128u /* conntrack events are on by default */
 
 void __nf_ct_ext_destroy(struct nf_conn *ct)
 {
@@ -46,9 +47,8 @@ EXPORT_SYMBOL(__nf_ct_ext_destroy);
 static void *
 nf_ct_ext_create(struct nf_ct_ext **ext, enum nf_ct_ext_id id, gfp_t gfp)
 {
-       unsigned int off, len;
+       unsigned int off, len, alloc;
        struct nf_ct_ext_type *t;
-       size_t alloc_size;
 
        rcu_read_lock();
        t = rcu_dereference(nf_ct_ext_types[id]);
@@ -59,10 +59,10 @@ nf_ct_ext_create(struct nf_ct_ext **ext, enum nf_ct_ext_id id, gfp_t gfp)
 
        off = ALIGN(sizeof(struct nf_ct_ext), t->align);
        len = off + t->len;
-       alloc_size = t->alloc_size;
        rcu_read_unlock();
 
-       *ext = kzalloc(alloc_size, gfp);
+       alloc = max(len, NF_CT_EXT_PREALLOC);
+       *ext = kzalloc(alloc, gfp);
        if (!*ext)
                return NULL;
 
@@ -115,41 +115,6 @@ void *nf_ct_ext_add(struct nf_conn *ct, enum nf_ct_ext_id id, gfp_t gfp)
 }
 EXPORT_SYMBOL(nf_ct_ext_add);
 
-static void update_alloc_size(struct nf_ct_ext_type *type)
-{
-       int i, j;
-       struct nf_ct_ext_type *t1, *t2;
-       enum nf_ct_ext_id min = 0, max = NF_CT_EXT_NUM - 1;
-
-       /* unnecessary to update all types */
-       if ((type->flags & NF_CT_EXT_F_PREALLOC) == 0) {
-               min = type->id;
-               max = type->id;
-       }
-
-       /* This assumes that extended areas in conntrack for the types
-          whose NF_CT_EXT_F_PREALLOC bit set are allocated in order */
-       for (i = min; i <= max; i++) {
-               t1 = rcu_dereference_protected(nf_ct_ext_types[i],
-                               lockdep_is_held(&nf_ct_ext_type_mutex));
-               if (!t1)
-                       continue;
-
-               t1->alloc_size = ALIGN(sizeof(struct nf_ct_ext), t1->align) +
-                                t1->len;
-               for (j = 0; j < NF_CT_EXT_NUM; j++) {
-                       t2 = rcu_dereference_protected(nf_ct_ext_types[j],
-                               lockdep_is_held(&nf_ct_ext_type_mutex));
-                       if (t2 == NULL || t2 == t1 ||
-                           (t2->flags & NF_CT_EXT_F_PREALLOC) == 0)
-                               continue;
-
-                       t1->alloc_size = ALIGN(t1->alloc_size, t2->align)
-                                        + t2->len;
-               }
-       }
-}
-
 /* This MUST be called in process context. */
 int nf_ct_extend_register(struct nf_ct_ext_type *type)
 {
@@ -161,12 +126,7 @@ int nf_ct_extend_register(struct nf_ct_ext_type *type)
                goto out;
        }
 
-       /* This ensures that nf_ct_ext_create() can allocate enough area
-          before updating alloc_size */
-       type->alloc_size = ALIGN(sizeof(struct nf_ct_ext), type->align)
-                          + type->len;
        rcu_assign_pointer(nf_ct_ext_types[type->id], type);
-       update_alloc_size(type);
 out:
        mutex_unlock(&nf_ct_ext_type_mutex);
        return ret;
@@ -178,7 +138,6 @@ void nf_ct_extend_unregister(struct nf_ct_ext_type *type)
 {
        mutex_lock(&nf_ct_ext_type_mutex);
        RCU_INIT_POINTER(nf_ct_ext_types[type->id], NULL);
-       update_alloc_size(type);
        mutex_unlock(&nf_ct_ext_type_mutex);
        synchronize_rcu();
 }

diff --git a/net/netfilter/nf_nat_core.c b/net/netfilter/nf_nat_core.c
index 9cbf49f9c1b712de6ff3f94b26ab2da10c9b684c..86eeacbb479372dbd25519fa6541b5677af28d2b 100644 (file)
--- a/net/netfilter/nf_nat_core.c
+++ b/net/netfilter/nf_nat_core.c
@@ -717,7 +717,6 @@ static struct nf_ct_ext_type nat_extend __read_mostly = {
        .align          = __alignof__(struct nf_conn_nat),
        .destroy        = nf_nat_cleanup_conntrack,
        .id             = NF_CT_EXT_NAT,
-       .flags          = NF_CT_EXT_F_PREALLOC,
 };
 
 #if IS_ENABLED(CONFIG_NF_CT_NETLINK)