ipv6: introduce tcp_v6_iif()

Commit 971f10eca186 ("tcp: better TCP_SKB_CB layout to reduce cache line
misses") added a regression for SO_BINDTODEVICE on IPv6.

This is because we still use inet6_iif() which expects that IP6 control
block is still at the beginning of skb->cb[]

This patch adds tcp_v6_iif() helper and uses it where necessary.

Because __inet6_lookup_skb() is used by TCP and DCCP, we add an iif
parameter to it.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Fixes: 971f10eca186 ("tcp: better TCP_SKB_CB layout to reduce cache line misses")
Acked-by: Cong Wang <cwang@twopensource.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 9 insertions, 0 deletions

diff --git a/include/net/tcp.h b/include/net/tcp.h
index 3a4bbbfdcf8d..c9766f89deba 100644
--- a/include/net/tcp.h
+++ b/include/net/tcp.h
@@ -729,6 +729,15 @@ struct tcp_skb_cb {
 
 #define TCP_SKB_CB(__skb)       ((struct tcp_skb_cb *)&((__skb)->cb[0]))
 
+
+/* This is the variant of inet6_iif() that must be used by TCP,
+ * as TCP moves IP6CB into a different location in skb->cb[]
+ */
+static inline int tcp_v6_iif(const struct sk_buff *skb)
+{
+        return TCP_SKB_CB(skb)->header.h6.iif;
+}
+
 /* Due to TSO, an SKB can be composed of multiple actual
  * packets.  To keep these tracked properly, we use this.
  */