bridge: move mac header copying into br_netfilter

The mac header only has to be copied back into the skb for
fragments generated by ip_fragment(), which only happens
for bridge forwarded packets with nf-call-iptables=1 && active nf_defrag.

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

diff --git a/include/linux/netfilter_bridge.h b/include/linux/netfilter_bridge.h
index c755e4971fa3cc89e3000b669e6f3ba557f555b8..332ef8ab37e9c61a0e780aff9fc551cad54cb301 100644 (file)
--- a/include/linux/netfilter_bridge.h
+++ b/include/linux/netfilter_bridge.h
@@ -44,36 +44,6 @@ static inline void nf_bridge_update_protocol(struct sk_buff *skb)
                skb->protocol = htons(ETH_P_PPP_SES);
 }
 
-/* Fill in the header for fragmented IP packets handled by
- * the IPv4 connection tracking code.
- *
- * Only used in br_forward.c
- */
-static inline int nf_bridge_copy_header(struct sk_buff *skb)
-{
-       int err;
-       unsigned int header_size;
-
-       nf_bridge_update_protocol(skb);
-       header_size = ETH_HLEN + nf_bridge_encap_header_len(skb);
-       err = skb_cow_head(skb, header_size);
-       if (err)
-               return err;
-
-       skb_copy_to_linear_data_offset(skb, -header_size,
-                                      skb->nf_bridge->data, header_size);
-       __skb_push(skb, nf_bridge_encap_header_len(skb));
-       return 0;
-}
-
-static inline int nf_bridge_maybe_copy_header(struct sk_buff *skb)
-{
-       if (skb->nf_bridge &&
-           skb->nf_bridge->mask & (BRNF_BRIDGED | BRNF_BRIDGED_DNAT))
-               return nf_bridge_copy_header(skb);
-       return 0;
-}
-
 static inline unsigned int nf_bridge_mtu_reduction(const struct sk_buff *skb)
 {
        if (unlikely(skb->nf_bridge->mask & BRNF_PPPoE))
@@ -119,7 +89,6 @@ static inline void br_drop_fake_rtable(struct sk_buff *skb)
 }
 
 #else
-#define nf_bridge_maybe_copy_header(skb)       (0)
 #define nf_bridge_pad(skb)                     (0)
 #define br_drop_fake_rtable(skb)               do { } while (0)
 #endif /* CONFIG_BRIDGE_NETFILTER */

diff --git a/net/bridge/br_forward.c b/net/bridge/br_forward.c
index f96933a823e327fe56f64d1005101309e78a8e49..32541d4f72e83d49258d73a460ee5ea2250ce835 100644 (file)
--- a/net/bridge/br_forward.c
+++ b/net/bridge/br_forward.c
@@ -37,9 +37,7 @@ static inline int should_deliver(const struct net_bridge_port *p,
 
 int br_dev_queue_push_xmit(struct sk_buff *skb)
 {
-       /* ip_fragment doesn't copy the MAC header */
-       if (nf_bridge_maybe_copy_header(skb) ||
-           !is_skb_forwardable(skb->dev, skb)) {
+       if (!is_skb_forwardable(skb->dev, skb)) {
                kfree_skb(skb);
        } else {
                skb_push(skb, ETH_HLEN);

diff --git a/net/bridge/br_netfilter.c b/net/bridge/br_netfilter.c
index 0ee453fad3de652142ddce3b6af6f1c3bb52e95a..e5479112c4a3daaaa139319ec1a0407f142a614b 100644 (file)
--- a/net/bridge/br_netfilter.c
+++ b/net/bridge/br_netfilter.c
@@ -764,6 +764,33 @@ static unsigned int br_nf_forward_arp(const struct nf_hook_ops *ops,
 }
 
 #if IS_ENABLED(CONFIG_NF_DEFRAG_IPV4)
+static bool nf_bridge_copy_header(struct sk_buff *skb)
+{
+       int err;
+       unsigned int header_size;
+
+       nf_bridge_update_protocol(skb);
+       header_size = ETH_HLEN + nf_bridge_encap_header_len(skb);
+       err = skb_cow_head(skb, header_size);
+       if (err)
+               return false;
+
+       skb_copy_to_linear_data_offset(skb, -header_size,
+                                      skb->nf_bridge->data, header_size);
+       __skb_push(skb, nf_bridge_encap_header_len(skb));
+       return true;
+}
+
+static int br_nf_push_frag_xmit(struct sk_buff *skb)
+{
+       if (!nf_bridge_copy_header(skb)) {
+               kfree_skb(skb);
+               return 0;
+       }
+
+       return br_dev_queue_push_xmit(skb);
+}
+
 static int br_nf_dev_queue_xmit(struct sk_buff *skb)
 {
        int ret;
@@ -780,7 +807,7 @@ static int br_nf_dev_queue_xmit(struct sk_buff *skb)
                        /* Drop invalid packet */
                        return NF_DROP;
                IPCB(skb)->frag_max_size = frag_max_size;
-               ret = ip_fragment(skb, br_dev_queue_push_xmit);
+               ret = ip_fragment(skb, br_nf_push_frag_xmit);
        } else
                ret = br_dev_queue_push_xmit(skb);