netfilter: xtables: use xt_table for hook instantiation

The respective xt_table structures already have most of the metadata
needed for hook setup. Add a 'priority' field to struct xt_table so
that xt_hook_link() can be called with a reduced number of arguments.

So should we be having more tables in the future, it comes at no
static cost (only runtime, as before) - space saved:
6807373->6806555.

Signed-off-by: Jan Engelhardt <jengelh@medozas.de>

4 files changed, 28 insertions, 112 deletions

diff --git a/net/ipv6/netfilter/ip6table_filter.c b/net/ipv6/netfilter/ip6table_filter.c
index 866f34ae236b..6e95d0614ca9 100644
--- a/net/ipv6/netfilter/ip6table_filter.c
+++ b/net/ipv6/netfilter/ip6table_filter.c
@@ -56,6 +56,7 @@ static const struct xt_table packet_filter = {
         .valid_hooks    = FILTER_VALID_HOOKS,
         .me             = THIS_MODULE,
         .af             = NFPROTO_IPV6,
+        .priority       = NF_IP6_PRI_FILTER,
 };
 
 /* The work comes in here from netfilter.c. */
@@ -69,29 +70,7 @@ ip6table_filter_hook(unsigned int hook, struct sk_buff *skb,
         return ip6t_do_table(skb, hook, in, out, net->ipv6.ip6table_filter);
 }
 
-static struct nf_hook_ops ip6t_ops[] __read_mostly = {
-        {
-                .hook           = ip6table_filter_hook,
-                .owner          = THIS_MODULE,
-                .pf             = NFPROTO_IPV6,
-                .hooknum        = NF_INET_LOCAL_IN,
-                .priority       = NF_IP6_PRI_FILTER,
-        },
-        {
-                .hook           = ip6table_filter_hook,
-                .owner          = THIS_MODULE,
-                .pf             = NFPROTO_IPV6,
-                .hooknum        = NF_INET_FORWARD,
-                .priority       = NF_IP6_PRI_FILTER,
-        },
-        {
-                .hook           = ip6table_filter_hook,
-                .owner          = THIS_MODULE,
-                .pf             = NFPROTO_IPV6,
-                .hooknum        = NF_INET_LOCAL_OUT,
-                .priority       = NF_IP6_PRI_FILTER,
-        },
-};
+static struct nf_hook_ops *filter_ops __read_mostly;
 
 /* Default to forward because I got too much mail already. */
 static int forward = NF_ACCEPT;
@@ -134,9 +113,11 @@ static int __init ip6table_filter_init(void)
                 return ret;
 
         /* Register hooks */
-        ret = nf_register_hooks(ip6t_ops, ARRAY_SIZE(ip6t_ops));
-        if (ret < 0)
+        filter_ops = xt_hook_link(&packet_filter, ip6table_filter_hook);
+        if (IS_ERR(filter_ops)) {
+                ret = PTR_ERR(filter_ops);
                 goto cleanup_table;
+        }
 
         return ret;
 
@@ -147,7 +128,7 @@ static int __init ip6table_filter_init(void)
 
 static void __exit ip6table_filter_fini(void)
 {
-        nf_unregister_hooks(ip6t_ops, ARRAY_SIZE(ip6t_ops));
+        xt_hook_unlink(&packet_filter, filter_ops);
         unregister_pernet_subsys(&ip6table_filter_net_ops);
 }
 
diff --git a/net/ipv6/netfilter/ip6table_mangle.c b/net/ipv6/netfilter/ip6table_mangle.c
index 405ac1f76390..5023ac52ffec 100644
--- a/net/ipv6/netfilter/ip6table_mangle.c
+++ b/net/ipv6/netfilter/ip6table_mangle.c
@@ -62,6 +62,7 @@ static const struct xt_table packet_mangler = {
         .valid_hooks    = MANGLE_VALID_HOOKS,
         .me             = THIS_MODULE,
         .af             = NFPROTO_IPV6,
+        .priority       = NF_IP6_PRI_MANGLE,
 };
 
 static unsigned int
@@ -122,44 +123,7 @@ ip6table_mangle_hook(unsigned int hook, struct sk_buff *skb,
                              dev_net(in)->ipv6.ip6table_mangle);
 }
 
-static struct nf_hook_ops ip6t_ops[] __read_mostly = {
-        {
-                .hook           = ip6table_mangle_hook,
-                .owner          = THIS_MODULE,
-                .pf             = NFPROTO_IPV6,
-                .hooknum        = NF_INET_PRE_ROUTING,
-                .priority       = NF_IP6_PRI_MANGLE,
-        },
-        {
-                .hook           = ip6table_mangle_hook,
-                .owner          = THIS_MODULE,
-                .pf             = NFPROTO_IPV6,
-                .hooknum        = NF_INET_LOCAL_IN,
-                .priority       = NF_IP6_PRI_MANGLE,
-        },
-        {
-                .hook           = ip6table_mangle_hook,
-                .owner          = THIS_MODULE,
-                .pf             = NFPROTO_IPV6,
-                .hooknum        = NF_INET_FORWARD,
-                .priority       = NF_IP6_PRI_MANGLE,
-        },
-        {
-                .hook           = ip6table_mangle_hook,
-                .owner          = THIS_MODULE,
-                .pf             = NFPROTO_IPV6,
-                .hooknum        = NF_INET_LOCAL_OUT,
-                .priority       = NF_IP6_PRI_MANGLE,
-        },
-        {
-                .hook           = ip6table_mangle_hook,
-                .owner          = THIS_MODULE,
-                .pf             = NFPROTO_IPV6,
-                .hooknum        = NF_INET_POST_ROUTING,
-                .priority       = NF_IP6_PRI_MANGLE,
-        },
-};
-
+static struct nf_hook_ops *mangle_ops __read_mostly;
 static int __net_init ip6table_mangle_net_init(struct net *net)
 {
         /* Register table */
@@ -189,9 +153,11 @@ static int __init ip6table_mangle_init(void)
                 return ret;
 
         /* Register hooks */
-        ret = nf_register_hooks(ip6t_ops, ARRAY_SIZE(ip6t_ops));
-        if (ret < 0)
+        mangle_ops = xt_hook_link(&packet_mangler, ip6table_mangle_hook);
+        if (IS_ERR(mangle_ops)) {
+                ret = PTR_ERR(mangle_ops);
                 goto cleanup_table;
+        }
 
         return ret;
 
@@ -202,7 +168,7 @@ static int __init ip6table_mangle_init(void)
 
 static void __exit ip6table_mangle_fini(void)
 {
-        nf_unregister_hooks(ip6t_ops, ARRAY_SIZE(ip6t_ops));
+        xt_hook_unlink(&packet_mangler, mangle_ops);
         unregister_pernet_subsys(&ip6table_mangle_net_ops);
 }
 
diff --git a/net/ipv6/netfilter/ip6table_raw.c b/net/ipv6/netfilter/ip6table_raw.c
index 5451a36fbc21..3bfa69511641 100644
--- a/net/ipv6/netfilter/ip6table_raw.c
+++ b/net/ipv6/netfilter/ip6table_raw.c
@@ -40,6 +40,7 @@ static const struct xt_table packet_raw = {
         .valid_hooks = RAW_VALID_HOOKS,
         .me = THIS_MODULE,
         .af = NFPROTO_IPV6,
+        .priority = NF_IP6_PRI_FIRST,
 };
 
 /* The work comes in here from netfilter.c. */
@@ -53,22 +54,7 @@ ip6table_raw_hook(unsigned int hook, struct sk_buff *skb,
         return ip6t_do_table(skb, hook, in, out, net->ipv6.ip6table_raw);
 }
 
-static struct nf_hook_ops ip6t_ops[] __read_mostly = {
-        {
-          .hook = ip6table_raw_hook,
-          .pf = NFPROTO_IPV6,
-          .hooknum = NF_INET_PRE_ROUTING,
-          .priority = NF_IP6_PRI_FIRST,
-          .owner = THIS_MODULE,
-        },
-        {
-          .hook = ip6table_raw_hook,
-          .pf = NFPROTO_IPV6,
-          .hooknum = NF_INET_LOCAL_OUT,
-          .priority = NF_IP6_PRI_FIRST,
-          .owner = THIS_MODULE,
-        },
-};
+static struct nf_hook_ops *rawtable_ops __read_mostly;
 
 static int __net_init ip6table_raw_net_init(struct net *net)
 {
@@ -99,9 +85,11 @@ static int __init ip6table_raw_init(void)
                 return ret;
 
         /* Register hooks */
-        ret = nf_register_hooks(ip6t_ops, ARRAY_SIZE(ip6t_ops));
-        if (ret < 0)
+        rawtable_ops = xt_hook_link(&packet_raw, ip6table_raw_hook);
+        if (IS_ERR(rawtable_ops)) {
+                ret = PTR_ERR(rawtable_ops);
                 goto cleanup_table;
+        }
 
         return ret;
 
@@ -112,7 +100,7 @@ static int __init ip6table_raw_init(void)
 
 static void __exit ip6table_raw_fini(void)
 {
-        nf_unregister_hooks(ip6t_ops, ARRAY_SIZE(ip6t_ops));
+        xt_hook_unlink(&packet_raw, rawtable_ops);
         unregister_pernet_subsys(&ip6table_raw_net_ops);
 }
 
diff --git a/net/ipv6/netfilter/ip6table_security.c b/net/ipv6/netfilter/ip6table_security.c
index 841ea77f5218..dd2200f17a6c 100644
--- a/net/ipv6/netfilter/ip6table_security.c
+++ b/net/ipv6/netfilter/ip6table_security.c
@@ -61,6 +61,7 @@ static const struct xt_table security_table = {
         .valid_hooks    = SECURITY_VALID_HOOKS,
         .me             = THIS_MODULE,
         .af             = NFPROTO_IPV6,
+        .priority       = NF_IP6_PRI_SECURITY,
 };
 
 static unsigned int
@@ -74,29 +75,7 @@ ip6table_security_hook(unsigned int hook, struct sk_buff *skb,
         return ip6t_do_table(skb, hook, in, out, net->ipv6.ip6table_security);
 }
 
-static struct nf_hook_ops ip6t_ops[] __read_mostly = {
-        {
-                .hook           = ip6table_security_hook,
-                .owner          = THIS_MODULE,
-                .pf             = NFPROTO_IPV6,
-                .hooknum        = NF_INET_LOCAL_IN,
-                .priority       = NF_IP6_PRI_SECURITY,
-        },
-        {
-                .hook           = ip6table_security_hook,
-                .owner          = THIS_MODULE,
-                .pf             = NFPROTO_IPV6,
-                .hooknum        = NF_INET_FORWARD,
-                .priority       = NF_IP6_PRI_SECURITY,
-        },
-        {
-                .hook           = ip6table_security_hook,
-                .owner          = THIS_MODULE,
-                .pf             = NFPROTO_IPV6,
-                .hooknum        = NF_INET_LOCAL_OUT,
-                .priority       = NF_IP6_PRI_SECURITY,
-        },
-};
+static struct nf_hook_ops *sectbl_ops __read_mostly;
 
 static int __net_init ip6table_security_net_init(struct net *net)
 {
@@ -127,9 +106,11 @@ static int __init ip6table_security_init(void)
         if (ret < 0)
                 return ret;
 
-        ret = nf_register_hooks(ip6t_ops, ARRAY_SIZE(ip6t_ops));
-        if (ret < 0)
+        sectbl_ops = xt_hook_link(&security_table, ip6table_security_hook);
+        if (IS_ERR(sectbl_ops)) {
+                ret = PTR_ERR(sectbl_ops);
                 goto cleanup_table;
+        }
 
         return ret;
 
@@ -140,7 +121,7 @@ cleanup_table:
 
 static void __exit ip6table_security_fini(void)
 {
-        nf_unregister_hooks(ip6t_ops, ARRAY_SIZE(ip6t_ops));
+        xt_hook_unlink(&security_table, sectbl_ops);
         unregister_pernet_subsys(&ip6table_security_net_ops);
 }