[NET]: Treat CHECKSUM_PARTIAL as CHECKSUM_UNNECESSARY

When a transmitted packet is looped back directly, CHECKSUM_PARTIAL
maps to the semantics of CHECKSUM_UNNECESSARY.  Therefore we should
treat it as such in the stack.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 1 insertions, 2 deletions

diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c
index a091a99ad263..5a3e7f839fc5 100644
--- a/net/ipv4/tcp_ipv4.c
+++ b/net/ipv4/tcp_ipv4.c
@@ -1638,8 +1638,7 @@ int tcp_v4_rcv(struct sk_buff *skb)
          * Packet length and doff are validated by header prediction,
          * provided case of th->doff==0 is eliminated.
          * So, we defer the checks. */
-        if ((skb->ip_summed != CHECKSUM_UNNECESSARY &&
-             tcp_v4_checksum_init(skb)))
+        if (!skb_csum_unnecessary(skb) && tcp_v4_checksum_init(skb))
                 goto bad_packet;
 
         th = tcp_hdr(skb);