[NETFILTER] bridge: code rearrangement for clarity

Cleanup and rearrangement for better style and clarity:
	Split the function nf_bridge_maybe_copy_header into two pieces
	Move copy portion out of line.
	Use Ethernet header size macros.
	Use header file to handle CONFIG_NETFILTER_BRIDGE differences

Signed-off-by: Stephen Hemminger <shemminger@osdl.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

3 files changed, 33 insertions, 25 deletions

diff --git a/include/linux/netfilter_bridge.h b/include/linux/netfilter_bridge.h
index 427c67ff89e9..274fe4b33155 100644
--- a/include/linux/netfilter_bridge.h
+++ b/include/linux/netfilter_bridge.h
@@ -47,26 +47,12 @@ enum nf_br_hook_priorities {
 
 
 /* Only used in br_forward.c */
-static inline
-int nf_bridge_maybe_copy_header(struct sk_buff *skb)
+extern int nf_bridge_copy_header(struct sk_buff *skb);
+static inline int nf_bridge_maybe_copy_header(struct sk_buff *skb)
 {
-        int err;
-
-        if (skb->nf_bridge) {
-                if (skb->protocol == __constant_htons(ETH_P_8021Q)) {
-                        err = skb_cow(skb, 18);
-                        if (err)
-                                return err;
-                        memcpy(skb->data - 18, skb->nf_bridge->data, 18);
-                        skb_push(skb, 4);
-                } else {
-                        err = skb_cow(skb, 16);
-                        if (err)
-                                return err;
-                        memcpy(skb->data - 16, skb->nf_bridge->data, 16);
-                }
-        }
-        return 0;
+        if (skb->nf_bridge)
+                return nf_bridge_copy_header(skb);
+        return 0;
 }
 
 /* This is called by the IP fragmenting code and it ensures there is
@@ -90,6 +76,8 @@ struct bridge_skb_cb {
 };
 
 extern int brnf_deferred_hooks;
+#else
+#define nf_bridge_maybe_copy_header(skb)        (0)
 #endif /* CONFIG_BRIDGE_NETFILTER */
 
 #endif /* __KERNEL__ */
diff --git a/net/bridge/br_forward.c b/net/bridge/br_forward.c
index 864fbbc7b24d..191b861e5e53 100644
--- a/net/bridge/br_forward.c
+++ b/net/bridge/br_forward.c
@@ -38,13 +38,10 @@ int br_dev_queue_push_xmit(struct sk_buff *skb)
         if (packet_length(skb) > skb->dev->mtu && !skb_is_gso(skb))
                 kfree_skb(skb);
         else {
-#ifdef CONFIG_BRIDGE_NETFILTER
                 /* ip_refrag calls ip_fragment, doesn't copy the MAC header. */
                 if (nf_bridge_maybe_copy_header(skb))
                         kfree_skb(skb);
-                else
-#endif
-                {
+                else {
                         skb_push(skb, ETH_HLEN);
 
                         dev_queue_xmit(skb);
diff --git a/net/bridge/br_netfilter.c b/net/bridge/br_netfilter.c
index 05b3de888243..b498efcfe451 100644
--- a/net/bridge/br_netfilter.c
+++ b/net/bridge/br_netfilter.c
@@ -127,14 +127,37 @@ static inline struct nf_bridge_info *nf_bridge_alloc(struct sk_buff *skb)
 
 static inline void nf_bridge_save_header(struct sk_buff *skb)
 {
-        int header_size = 16;
+        int header_size = ETH_HLEN;
 
         if (skb->protocol == htons(ETH_P_8021Q))
-                header_size = 18;
+                header_size += VLAN_HLEN;
 
         memcpy(skb->nf_bridge->data, skb->data - header_size, header_size);
 }
 
+/*
+ * When forwarding bridge frames, we save a copy of the original
+ * header before processing.
+ */
+int nf_bridge_copy_header(struct sk_buff *skb)
+{
+        int err;
+        int header_size = ETH_HLEN;
+
+        if (skb->protocol == htons(ETH_P_8021Q))
+                header_size += VLAN_HLEN;
+
+        err = skb_cow(skb, header_size);
+        if (err)
+                return err;
+
+        memcpy(skb->data - header_size, skb->nf_bridge->data, header_size);
+
+        if (skb->protocol == htons(ETH_P_8021Q))
+                __skb_push(skb, VLAN_HLEN);
+        return 0;
+}
+
 /* PF_BRIDGE/PRE_ROUTING *********************************************/
 /* Undo the changes made for ip6tables PREROUTING and continue the
  * bridge PRE_ROUTING hook. */