igb: Correctly get protocol information

We can't look at the socket to get protocol information. We should
instead look directly at the packet, and hope there are no IPv6
option headers.

Signed-off-by: Mitch Williams <mitch.a.williams@intel.com>
Signed-off-by: Auke Kok <auke-jan.h.kok@intel.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>

drivers/net/igb/igb_main.c

@@ -31,7 +31,6 @@
 #include <linux/vmalloc.h>
 #include <linux/pagemap.h>
 #include <linux/netdevice.h>
-#include <linux/tcp.h>
 #include <linux/ipv6.h>
 #include <net/checksum.h>
 #include <net/ip6_checksum.h>
@@ -2484,10 +2483,24 @@ static inline bool igb_tx_csum_adv(struct igb_adapter *adapter,
 		tu_cmd |= (E1000_TXD_CMD_DEXT | E1000_ADVTXD_DTYP_CTXT);
 
 		if (skb->ip_summed == CHECKSUM_PARTIAL) {
-			if (skb->protocol == htons(ETH_P_IP))
+			switch (skb->protocol) {
+			case __constant_htons(ETH_P_IP):
 				tu_cmd |= E1000_ADVTXD_TUCMD_IPV4;
-			if (skb->sk && (skb->sk->sk_protocol == IPPROTO_TCP))
-				tu_cmd |= E1000_ADVTXD_TUCMD_L4T_TCP;
+				if (ip_hdr(skb)->protocol == IPPROTO_TCP)
+					tu_cmd |= E1000_ADVTXD_TUCMD_L4T_TCP;
+				break;
+			case __constant_htons(ETH_P_IPV6):
+				/* XXX what about other V6 headers?? */
+				if (ipv6_hdr(skb)->nexthdr == IPPROTO_TCP)
+					tu_cmd |= E1000_ADVTXD_TUCMD_L4T_TCP;
+				break;
+			default:
+				if (unlikely(net_ratelimit()))
+					dev_warn(&adapter->pdev->dev,
+					    "partial checksum but proto=%x!\n",
+					    skb->protocol);
+				break;
+			}
 		}
 
 		context_desc->type_tucmd_mlhl = cpu_to_le32(tu_cmd);