Subject: [PATCH 12/48] udpv6: Fix the checksum computation when HW checksum does not apply

From: Subash Abhinov Kasiviswanathan <[email-masked]>
Date: Wed, 13 Sep 2017 19:30:51 -0600

[ Upstream commit 63ecc3d9436f8012e49dc846d6cb0a85a3433517 ]

While trying an ESP transport mode encryption for UDPv6 packets of
datagram size 1436 with MTU 1500, checksum error was observed in
the secondary fragment.

This error occurs due to the UDP payload checksum being missed out
when computing the full checksum for these packets in
udp6_hwcsum_outgoing().

Fixes: d39d938c8228 ("ipv6: Introduce udpv6_send_skb()")
Signed-off-by: Subash Abhinov Kasiviswanathan <[email-masked]>
Signed-off-by: David S. Miller <[email-masked]>
---
 net/ipv6/udp.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/net/ipv6/udp.c b/net/ipv6/udp.c
index d6886228e1d0..30b4d55e88f3 100644
--- a/net/ipv6/udp.c
+++ b/net/ipv6/udp.c
@@ -1011,6 +1011,7 @@ static void udp6_hwcsum_outgoing(struct sock *sk, struct sk_buff *skb,
 		 */
 		offset = skb_transport_offset(skb);
 		skb->csum = skb_checksum(skb, offset, skb->len - offset, 0);
+		csum = skb->csum;
 
 		skb->ip_summed = CHECKSUM_NONE;
 
-- 
2.13.6