netfilter: xtables: compact table hook functions (1/2)

This patch combines all the per-hook functions in a given table into
a single function. Together with the 2nd patch, further
simplifications are possible up to the point of output code reduction.

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

4 files changed, 51 insertions, 106 deletions

diff --git a/net/ipv6/netfilter/ip6table_filter.c b/net/ipv6/netfilter/ip6table_filter.c
index 33ddfe5..38074e93 100644
--- a/net/ipv6/netfilter/ip6table_filter.c
+++ b/net/ipv6/netfilter/ip6table_filter.c
@@ -60,54 +60,36 @@ static const struct xt_table packet_filter = {
 
 /* The work comes in here from netfilter.c. */
 static unsigned int
-ip6t_in_hook(unsigned int hook,
-		   struct sk_buff *skb,
-		   const struct net_device *in,
-		   const struct net_device *out,
-		   int (*okfn)(struct sk_buff *))
+ip6table_filter_hook(unsigned int hook, struct sk_buff *skb,
+		     const struct net_device *in, const struct net_device *out,
+		     int (*okfn)(struct sk_buff *))
 {
-	return ip6t_do_table(skb, hook, in, out,
-			     dev_net(in)->ipv6.ip6table_filter);
-}
-
-static unsigned int
-ip6t_local_out_hook(unsigned int hook,
-		   struct sk_buff *skb,
-		   const struct net_device *in,
-		   const struct net_device *out,
-		   int (*okfn)(struct sk_buff *))
-{
-#if 0
-	/* root is playing with raw sockets. */
-	if (skb->len < sizeof(struct iphdr) ||
-	    ip_hdrlen(skb) < sizeof(struct iphdr)) {
-		if (net_ratelimit())
-			printk("ip6t_hook: happy cracking.\n");
-		return NF_ACCEPT;
-	}
-#endif
+	if (hook == NF_INET_LOCAL_OUT)
+		return ip6t_do_table(skb, hook, in, out,
+				     dev_net(out)->ipv6.ip6table_filter);
 
+	/* INPUT/FORWARD: */
 	return ip6t_do_table(skb, hook, in, out,
-			     dev_net(out)->ipv6.ip6table_filter);
+			     dev_net(in)->ipv6.ip6table_filter);
 }
 
 static struct nf_hook_ops ip6t_ops[] __read_mostly = {
 	{
-		.hook		= ip6t_in_hook,
+		.hook		= ip6table_filter_hook,
 		.owner		= THIS_MODULE,
 		.pf		= NFPROTO_IPV6,
 		.hooknum	= NF_INET_LOCAL_IN,
 		.priority	= NF_IP6_PRI_FILTER,
 	},
 	{
-		.hook		= ip6t_in_hook,
+		.hook		= ip6table_filter_hook,
 		.owner		= THIS_MODULE,
 		.pf		= NFPROTO_IPV6,
 		.hooknum	= NF_INET_FORWARD,
 		.priority	= NF_IP6_PRI_FILTER,
 	},
 	{
-		.hook		= ip6t_local_out_hook,
+		.hook		= ip6table_filter_hook,
 		.owner		= THIS_MODULE,
 		.pf		= NFPROTO_IPV6,
 		.hooknum	= NF_INET_LOCAL_OUT,
diff --git a/net/ipv6/netfilter/ip6table_mangle.c b/net/ipv6/netfilter/ip6table_mangle.c
index 9bc483f..405ac1f 100644
--- a/net/ipv6/netfilter/ip6table_mangle.c
+++ b/net/ipv6/netfilter/ip6table_mangle.c
@@ -64,33 +64,9 @@ static const struct xt_table packet_mangler = {
 	.af		= NFPROTO_IPV6,
 };
 
-/* The work comes in here from netfilter.c. */
-static unsigned int
-ip6t_in_hook(unsigned int hook,
-	 struct sk_buff *skb,
-	 const struct net_device *in,
-	 const struct net_device *out,
-	 int (*okfn)(struct sk_buff *))
-{
-	return ip6t_do_table(skb, hook, in, out,
-			     dev_net(in)->ipv6.ip6table_mangle);
-}
-
-static unsigned int
-ip6t_post_routing_hook(unsigned int hook,
-		struct sk_buff *skb,
-		const struct net_device *in,
-		const struct net_device *out,
-		int (*okfn)(struct sk_buff *))
-{
-	return ip6t_do_table(skb, hook, in, out,
-			     dev_net(out)->ipv6.ip6table_mangle);
-}
-
 static unsigned int
 ip6t_local_out_hook(unsigned int hook,
 		   struct sk_buff *skb,
-		   const struct net_device *in,
 		   const struct net_device *out,
 		   int (*okfn)(struct sk_buff *))
 {
@@ -119,7 +95,7 @@ ip6t_local_out_hook(unsigned int hook,
 	/* flowlabel and prio (includes version, which shouldn't change either */
 	flowlabel = *((u_int32_t *)ipv6_hdr(skb));
 
-	ret = ip6t_do_table(skb, hook, in, out,
+	ret = ip6t_do_table(skb, hook, NULL, out,
 			    dev_net(out)->ipv6.ip6table_mangle);
 
 	if (ret != NF_DROP && ret != NF_STOLEN &&
@@ -132,37 +108,51 @@ ip6t_local_out_hook(unsigned int hook,
 	return ret;
 }
 
+/* The work comes in here from netfilter.c. */
+static unsigned int
+ip6table_mangle_hook(unsigned int hook, struct sk_buff *skb,
+		     const struct net_device *in, const struct net_device *out,
+		     int (*okfn)(struct sk_buff *))
+{
+	if (hook == NF_INET_LOCAL_OUT)
+		return ip6t_local_out_hook(hook, skb, out, okfn);
+
+	/* INPUT/FORWARD */
+	return ip6t_do_table(skb, hook, in, out,
+			     dev_net(in)->ipv6.ip6table_mangle);
+}
+
 static struct nf_hook_ops ip6t_ops[] __read_mostly = {
 	{
-		.hook		= ip6t_in_hook,
+		.hook		= ip6table_mangle_hook,
 		.owner		= THIS_MODULE,
 		.pf		= NFPROTO_IPV6,
 		.hooknum	= NF_INET_PRE_ROUTING,
 		.priority	= NF_IP6_PRI_MANGLE,
 	},
 	{
-		.hook		= ip6t_in_hook,
+		.hook		= ip6table_mangle_hook,
 		.owner		= THIS_MODULE,
 		.pf		= NFPROTO_IPV6,
 		.hooknum	= NF_INET_LOCAL_IN,
 		.priority	= NF_IP6_PRI_MANGLE,
 	},
 	{
-		.hook		= ip6t_in_hook,
+		.hook		= ip6table_mangle_hook,
 		.owner		= THIS_MODULE,
 		.pf		= NFPROTO_IPV6,
 		.hooknum	= NF_INET_FORWARD,
 		.priority	= NF_IP6_PRI_MANGLE,
 	},
 	{
-		.hook		= ip6t_local_out_hook,
+		.hook		= ip6table_mangle_hook,
 		.owner		= THIS_MODULE,
 		.pf		= NFPROTO_IPV6,
 		.hooknum	= NF_INET_LOCAL_OUT,
 		.priority	= NF_IP6_PRI_MANGLE,
 	},
 	{
-		.hook		= ip6t_post_routing_hook,
+		.hook		= ip6table_mangle_hook,
 		.owner		= THIS_MODULE,
 		.pf		= NFPROTO_IPV6,
 		.hooknum	= NF_INET_POST_ROUTING,
diff --git a/net/ipv6/netfilter/ip6table_raw.c b/net/ipv6/netfilter/ip6table_raw.c
index 4c90b55..985e27c 100644
--- a/net/ipv6/netfilter/ip6table_raw.c
+++ b/net/ipv6/netfilter/ip6table_raw.c
@@ -44,37 +44,29 @@ static const struct xt_table packet_raw = {
 
 /* The work comes in here from netfilter.c. */
 static unsigned int
-ip6t_pre_routing_hook(unsigned int hook,
-	 struct sk_buff *skb,
-	 const struct net_device *in,
-	 const struct net_device *out,
-	 int (*okfn)(struct sk_buff *))
+ip6table_raw_hook(unsigned int hook, struct sk_buff *skb,
+		  const struct net_device *in, const struct net_device *out,
+		  int (*okfn)(struct sk_buff *))
 {
-	return ip6t_do_table(skb, hook, in, out,
-			     dev_net(in)->ipv6.ip6table_raw);
-}
+	if (hook == NF_INET_PRE_ROUTING)
+		return ip6t_do_table(skb, hook, in, out,
+				     dev_net(in)->ipv6.ip6table_raw);
 
-static unsigned int
-ip6t_local_out_hook(unsigned int hook,
-	 struct sk_buff *skb,
-	 const struct net_device *in,
-	 const struct net_device *out,
-	 int (*okfn)(struct sk_buff *))
-{
+	/* OUTPUT: */
 	return ip6t_do_table(skb, hook, in, out,
 			     dev_net(out)->ipv6.ip6table_raw);
 }
 
 static struct nf_hook_ops ip6t_ops[] __read_mostly = {
 	{
-	  .hook = ip6t_pre_routing_hook,
+	  .hook = ip6table_raw_hook,
 	  .pf = NFPROTO_IPV6,
 	  .hooknum = NF_INET_PRE_ROUTING,
 	  .priority = NF_IP6_PRI_FIRST,
 	  .owner = THIS_MODULE,
 	},
 	{
-	  .hook = ip6t_local_out_hook,
+	  .hook = ip6table_raw_hook,
 	  .pf = NFPROTO_IPV6,
 	  .hooknum = NF_INET_LOCAL_OUT,
 	  .priority = NF_IP6_PRI_FIRST,
diff --git a/net/ipv6/netfilter/ip6table_security.c b/net/ipv6/netfilter/ip6table_security.c
index baa8d4e..8358589 100644
--- a/net/ipv6/netfilter/ip6table_security.c
+++ b/net/ipv6/netfilter/ip6table_security.c
@@ -64,56 +64,37 @@ static const struct xt_table security_table = {
 };
 
 static unsigned int
-ip6t_local_in_hook(unsigned int hook,
-		   struct sk_buff *skb,
-		   const struct net_device *in,
-		   const struct net_device *out,
-		   int (*okfn)(struct sk_buff *))
+ip6table_security_hook(unsigned int hook, struct sk_buff *skb,
+		       const struct net_device *in,
+		       const struct net_device *out,
+		       int (*okfn)(struct sk_buff *))
 {
-	return ip6t_do_table(skb, hook, in, out,
-			     dev_net(in)->ipv6.ip6table_security);
-}
+	if (hook == NF_INET_LOCAL_OUT)
+		return ip6t_do_table(skb, hook, in, out,
+				     dev_net(out)->ipv6.ip6table_security);
 
-static unsigned int
-ip6t_forward_hook(unsigned int hook,
-		  struct sk_buff *skb,
-		  const struct net_device *in,
-		  const struct net_device *out,
-		  int (*okfn)(struct sk_buff *))
-{
+	/* INPUT/FORWARD: */
 	return ip6t_do_table(skb, hook, in, out,
 			     dev_net(in)->ipv6.ip6table_security);
 }
 
-static unsigned int
-ip6t_local_out_hook(unsigned int hook,
-		    struct sk_buff *skb,
-		    const struct net_device *in,
-		    const struct net_device *out,
-		    int (*okfn)(struct sk_buff *))
-{
-	/* TBD: handle short packets via raw socket */
-	return ip6t_do_table(skb, hook, in, out,
-			     dev_net(out)->ipv6.ip6table_security);
-}
-
 static struct nf_hook_ops ip6t_ops[] __read_mostly = {
 	{
-		.hook		= ip6t_local_in_hook,
+		.hook		= ip6table_security_hook,
 		.owner		= THIS_MODULE,
 		.pf		= NFPROTO_IPV6,
 		.hooknum	= NF_INET_LOCAL_IN,
 		.priority	= NF_IP6_PRI_SECURITY,
 	},
 	{
-		.hook		= ip6t_forward_hook,
+		.hook		= ip6table_security_hook,
 		.owner		= THIS_MODULE,
 		.pf		= NFPROTO_IPV6,
 		.hooknum	= NF_INET_FORWARD,
 		.priority	= NF_IP6_PRI_SECURITY,
 	},
 	{
-		.hook		= ip6t_local_out_hook,
+		.hook		= ip6table_security_hook,
 		.owner		= THIS_MODULE,
 		.pf		= NFPROTO_IPV6,
 		.hooknum	= NF_INET_LOCAL_OUT,