[Patch net] ipv4: clear all TCP_SKB_CB before passing to network layer

[Cong Wang <xiyou.wangcong@gmail.com>]

From: Cong Wang <cwang@twopensource.com>

Probably not a big deal, but IP is not the only network protocol,
don't clear skb->cb just for IP.

Also, IPv6 header is not always defined in struct tcp_skb_cb.

Cc: Krzysztof Kolasa <kkolasa@winsoft.pl>
Cc: Eric Dumazet <edumazet@google.com>
Signed-off-by: Cong Wang <cwang@twopensource.com>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
---
 net/ipv4/tcp_output.c | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c
index e13d778..ee356e5 100644
--- a/net/ipv4/tcp_output.c
+++ b/net/ipv4/tcp_output.c
@@ -1005,9 +1005,7 @@ static int tcp_transmit_skb(struct sock *sk, struct sk_buff *skb, int clone_it,
 	/* Our usage of tstamp should remain private */
 	skb->tstamp.tv64 = 0;
 
-	/* Cleanup our debris for IP stacks */
-	memset(skb->cb, 0, max(sizeof(struct inet_skb_parm),
-			       sizeof(struct inet6_skb_parm)));
+	memset(TCP_SKB_CB(skb), 0, sizeof(*TCP_SKB_CB(skb)));
 
 	err = icsk->icsk_af_ops->queue_xmit(sk, skb, &inet->cork.fl);
 
-- 
1.8.3.1