8139cp: fix checksum broken

[ Upstream commit 24b7ea9f6c9787fad885442ed0cc010f1aa69cca ]

I am not family with RealTek RTL-8139C+ series 10/100 PCI Ethernet driver.
I try to guess the meaning of RxProtoIP and IPFail.
RxProtoIP stands for received IPv4 packet that upper protocol is not tcp and udp.
!(status & IPFail) is true means that driver correctly to check checksum in IPv4 header.

If these are right, driver will set ip_summed with CHECKSUM_UNNECESSARY for other
upper protocol, e.g. sctp, igmp protocol. This will cause protocol stack ignores
checksum check for packets with invalid checksum.

This patch is only compile-test.

Signed-off-by: Shan Wei <shanwei@cn.fujitsu.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/drivers/net/8139cp.c b/drivers/net/8139cp.c
index 4a4f6b81e32de9ae8c85f9dd6aa379927d0ffaa0..70609eefc2dec1a9b97ac6d749c2f76bb27c139b 100644 (file)
--- a/drivers/net/8139cp.c
+++ b/drivers/net/8139cp.c
@@ -490,13 +490,11 @@ static inline unsigned int cp_rx_csum_ok (u32 status)
 {
        unsigned int protocol = (status >> 16) & 0x3;
 
-       if (likely((protocol == RxProtoTCP) && (!(status & TCPFail))))
+       if (((protocol == RxProtoTCP) && !(status & TCPFail)) ||
+           ((protocol == RxProtoUDP) && !(status & UDPFail)))
                return 1;
-       else if ((protocol == RxProtoUDP) && (!(status & UDPFail)))
-               return 1;
-       else if ((protocol == RxProtoIP) && (!(status & IPFail)))
-               return 1;
-       return 0;
+       else
+               return 0;
 }
 
 static int cp_rx_poll(struct napi_struct *napi, int budget)