igb: Mask off check of frag_off as we only want fragment offset

We were incorrectly checking the entire frag_off field when we only wanted the
fragment offset.  As a result we were not pulling in TCP headers when the DNF
flag was set.

To correct that we will now check for frag off using the IP_OFFSET mask.

Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com>
Tested-by: Aaron Brown <aaron.f.brown@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>

diff --git a/drivers/net/ethernet/intel/igb/igb_main.c b/drivers/net/ethernet/intel/igb/igb_main.c
index 7f83bb1..2f3dab0 100644 (file)
--- a/drivers/net/ethernet/intel/igb/igb_main.c
+++ b/drivers/net/ethernet/intel/igb/igb_main.c
@@ -6472,7 +6472,7 @@ static unsigned int igb_get_headlen(unsigned char *data,
                        return hdr.network - data;
 
                /* record next protocol if header is present */
-               if (!hdr.ipv4->frag_off)
+               if (!(hdr.ipv4->frag_off & htons(IP_OFFSET)))
                        nexthdr = hdr.ipv4->protocol;
        } else if (protocol == __constant_htons(ETH_P_IPV6)) {
                if ((hdr.network - data) > (max_len - sizeof(struct ipv6hdr)))