[NETFILTER]: Avoid skb_copy/pskb_copy/skb_realloc_headroom

This patch replaces unnecessary uses of skb_copy, pskb_copy and
skb_realloc_headroom by functions such as skb_make_writable and
pskb_expand_head.

This allows us to remove the double pointers later.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>

3 files changed, 9 insertions, 30 deletions

diff --git a/net/bridge/netfilter/ebt_dnat.c b/net/bridge/netfilter/ebt_dnat.c
index 4582659dff0e..9d74dee20ab0 100644
--- a/net/bridge/netfilter/ebt_dnat.c
+++ b/net/bridge/netfilter/ebt_dnat.c
@@ -8,6 +8,7 @@
  *
  */
 
+#include <linux/netfilter.h>
 #include <linux/netfilter_bridge/ebtables.h>
 #include <linux/netfilter_bridge/ebt_nat.h>
 #include <linux/module.h>
@@ -19,17 +20,9 @@ static int ebt_target_dnat(struct sk_buff **pskb, unsigned int hooknr,
 {
         struct ebt_nat_info *info = (struct ebt_nat_info *)data;
 
-        if (skb_shared(*pskb) || skb_cloned(*pskb)) {
-                struct sk_buff *nskb;
+        if (skb_make_writable(*pskb, 0))
+                return NF_DROP;
 
-                nskb = skb_copy(*pskb, GFP_ATOMIC);
-                if (!nskb)
-                        return NF_DROP;
-                if ((*pskb)->sk)
-                        skb_set_owner_w(nskb, (*pskb)->sk);
-                kfree_skb(*pskb);
-                *pskb = nskb;
-        }
         memcpy(eth_hdr(*pskb)->h_dest, info->mac, ETH_ALEN);
         return info->target;
 }
diff --git a/net/bridge/netfilter/ebt_redirect.c b/net/bridge/netfilter/ebt_redirect.c
index 9f378eab72d0..81371cd01bd0 100644
--- a/net/bridge/netfilter/ebt_redirect.c
+++ b/net/bridge/netfilter/ebt_redirect.c
@@ -8,6 +8,7 @@
  *
  */
 
+#include <linux/netfilter.h>
 #include <linux/netfilter_bridge/ebtables.h>
 #include <linux/netfilter_bridge/ebt_redirect.h>
 #include <linux/module.h>
@@ -20,17 +21,9 @@ static int ebt_target_redirect(struct sk_buff **pskb, unsigned int hooknr,
 {
         struct ebt_redirect_info *info = (struct ebt_redirect_info *)data;
 
-        if (skb_shared(*pskb) || skb_cloned(*pskb)) {
-                struct sk_buff *nskb;
+        if (skb_make_writable(*pskb, 0))
+                return NF_DROP;
 
-                nskb = skb_copy(*pskb, GFP_ATOMIC);
-                if (!nskb)
-                        return NF_DROP;
-                if ((*pskb)->sk)
-                        skb_set_owner_w(nskb, (*pskb)->sk);
-                kfree_skb(*pskb);
-                *pskb = nskb;
-        }
         if (hooknr != NF_BR_BROUTING)
                 memcpy(eth_hdr(*pskb)->h_dest,
                        in->br_port->br->dev->dev_addr, ETH_ALEN);
diff --git a/net/bridge/netfilter/ebt_snat.c b/net/bridge/netfilter/ebt_snat.c
index a50722182bfe..b0c63684e2f5 100644
--- a/net/bridge/netfilter/ebt_snat.c
+++ b/net/bridge/netfilter/ebt_snat.c
@@ -8,6 +8,7 @@
  *
  */
 
+#include <linux/netfilter.h>
 #include <linux/netfilter_bridge/ebtables.h>
 #include <linux/netfilter_bridge/ebt_nat.h>
 #include <linux/module.h>
@@ -21,17 +22,9 @@ static int ebt_target_snat(struct sk_buff **pskb, unsigned int hooknr,
 {
         struct ebt_nat_info *info = (struct ebt_nat_info *) data;
 
-        if (skb_shared(*pskb) || skb_cloned(*pskb)) {
-                struct sk_buff *nskb;
+        if (skb_make_writable(*pskb, 0))
+                return NF_DROP;
 
-                nskb = skb_copy(*pskb, GFP_ATOMIC);
-                if (!nskb)
-                        return NF_DROP;
-                if ((*pskb)->sk)
-                        skb_set_owner_w(nskb, (*pskb)->sk);
-                kfree_skb(*pskb);
-                *pskb = nskb;
-        }
         memcpy(eth_hdr(*pskb)->h_source, info->mac, ETH_ALEN);
         if (!(info->target & NAT_ARP_BIT) &&
             eth_hdr(*pskb)->h_proto == htons(ETH_P_ARP)) {