i40e: Rx checksum offload for VXLAN

This implements receive offload for VXLAN for i40e.  The hardware
supports checksum offload/verification of the inner/outer header.

Change-Id: I450db300af6713f2044fef1191a0d1d294c13369
Signed-off-by: Joseph Gasparakis <joseph.gasparakis@intel.com>
Signed-off-by: Jesse Brandeburg <jesse.brandeburg@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>

drivers/net/ethernet/intel/i40e/i40e.h

@@ -29,6 +29,7 @@
 #define _I40E_H_
 
 #include <net/tcp.h>
+#include <net/udp.h>
 #include <linux/init.h>
 #include <linux/types.h>
 #include <linux/errno.h>

drivers/net/ethernet/intel/i40e/i40e_txrx.c

@@ -860,12 +860,25 @@ static void i40e_receive_skb(struct i40e_ring *rx_ring,
  * @skb: skb currently being received and modified
  * @rx_status: status value of last descriptor in packet
  * @rx_error: error value of last descriptor in packet
+ * @rx_ptype: ptype value of last descriptor in packet
  **/
 static inline void i40e_rx_checksum(struct i40e_vsi *vsi,
 				    struct sk_buff *skb,
 				    u32 rx_status,
-				    u32 rx_error)
+				    u32 rx_error,
+				    u16 rx_ptype)
 {
+	bool ipv4_tunnel, ipv6_tunnel;
+	__wsum rx_udp_csum;
+	__sum16 csum;
+	struct iphdr *iph;
+
+	ipv4_tunnel = (rx_ptype > I40E_RX_PTYPE_GRENAT4_MAC_PAY3) &&
+		      (rx_ptype < I40E_RX_PTYPE_GRENAT4_MACVLAN_IPV6_ICMP_PAY4);
+	ipv6_tunnel = (rx_ptype > I40E_RX_PTYPE_GRENAT6_MAC_PAY3) &&
+		      (rx_ptype < I40E_RX_PTYPE_GRENAT6_MACVLAN_IPV6_ICMP_PAY4);
+
+	skb->encapsulation = ipv4_tunnel || ipv6_tunnel;
 	skb->ip_summed = CHECKSUM_NONE;
 
 	/* Rx csum enabled and ip headers found? */
@@ -873,12 +886,42 @@ static inline void i40e_rx_checksum(struct i40e_vsi *vsi,
 	      rx_status & (1 << I40E_RX_DESC_STATUS_L3L4P_SHIFT)))
 		return;
 
-	/* IP or L4 checksum error */
+	/* IP or L4 or outmost IP checksum error */
 	if (rx_error & ((1 << I40E_RX_DESC_ERROR_IPE_SHIFT) |
-			(1 << I40E_RX_DESC_ERROR_L4E_SHIFT))) {
+			(1 << I40E_RX_DESC_ERROR_L4E_SHIFT) |
+			(1 << I40E_RX_DESC_ERROR_EIPE_SHIFT))) {
+		vsi->back->hw_csum_rx_error++;
+		return;
+	}
+
+	if (ipv4_tunnel &&
+	    !(rx_status & (1 << I40E_RX_DESC_STATUS_UDP_0_SHIFT))) {
+		/* If VXLAN traffic has an outer UDPv4 checksum we need to check
+		 * it in the driver, hardware does not do it for us.
+		 * Since L3L4P bit was set we assume a valid IHL value (>=5)
+		 * so the total length of IPv4 header is IHL*4 bytes
+		 */
+		skb->transport_header = skb->mac_header +
+					sizeof(struct ethhdr) +
+					(ip_hdr(skb)->ihl * 4);
+
+		/* Add 4 bytes for VLAN tagged packets */
+		skb->transport_header += (skb->protocol == htons(ETH_P_8021Q) ||
+					  skb->protocol == htons(ETH_P_8021AD))
+					  ? VLAN_HLEN : 0;
+
+		rx_udp_csum = udp_csum(skb);
+		iph = ip_hdr(skb);
+		csum = csum_tcpudp_magic(
+				iph->saddr, iph->daddr,
+				(skb->len - skb_transport_offset(skb)),
+				IPPROTO_UDP, rx_udp_csum);
+
+		if (udp_hdr(skb)->check != csum) {
 			vsi->back->hw_csum_rx_error++;
 			return;
 		}
+	}
 
 	skb->ip_summed = CHECKSUM_UNNECESSARY;
 }
@@ -920,6 +963,7 @@ static int i40e_clean_rx_irq(struct i40e_ring *rx_ring, int budget)
 	union i40e_rx_desc *rx_desc;
 	u32 rx_error, rx_status;
 	u64 qword;
+	u16 rx_ptype;
 
 	rx_desc = I40E_RX_DESC(rx_ring, i);
 	qword = le64_to_cpu(rx_desc->wb.qword1.status_error_len);
@@ -952,6 +996,8 @@ static int i40e_clean_rx_irq(struct i40e_ring *rx_ring, int budget)
 		rx_hbo = rx_error & (1 << I40E_RX_DESC_ERROR_HBO_SHIFT);
 		rx_error &= ~(1 << I40E_RX_DESC_ERROR_HBO_SHIFT);
 
+		rx_ptype = (qword & I40E_RXD_QW1_PTYPE_MASK) >>
+			   I40E_RXD_QW1_PTYPE_SHIFT;
 		rx_bi->skb = NULL;
 
 		/* This memory barrier is needed to keep us from reading
@@ -1032,13 +1078,14 @@ static int i40e_clean_rx_irq(struct i40e_ring *rx_ring, int budget)
 		}
 
 		skb->rxhash = i40e_rx_hash(rx_ring, rx_desc);
-		i40e_rx_checksum(vsi, skb, rx_status, rx_error);
-
 		/* probably a little skewed due to removing CRC */
 		total_rx_bytes += skb->len;
 		total_rx_packets++;
 
 		skb->protocol = eth_type_trans(skb, rx_ring->netdev);
+
+		i40e_rx_checksum(vsi, skb, rx_status, rx_error, rx_ptype);
+
 		vlan_tag = rx_status & (1 << I40E_RX_DESC_STATUS_L2TAG1P_SHIFT)
 			 ? le16_to_cpu(rx_desc->wb.qword0.lo_dword.l2tag1)
 			 : 0;

drivers/net/ethernet/intel/i40e/i40e_type.h

@@ -513,7 +513,8 @@ enum i40e_rx_desc_status_bits {
 	I40E_RX_DESC_STATUS_UMBCAST_SHIFT	= 9, /* 2 BITS */
 	I40E_RX_DESC_STATUS_FLM_SHIFT		= 11,
 	I40E_RX_DESC_STATUS_FLTSTAT_SHIFT	= 12, /* 2 BITS */
-	I40E_RX_DESC_STATUS_LPBK_SHIFT		= 14
+	I40E_RX_DESC_STATUS_LPBK_SHIFT		= 14,
+	I40E_RX_DESC_STATUS_UDP_0_SHIFT		= 16
 };
 
 #define I40E_RXD_QW1_STATUS_TSYNINDX_SHIFT   I40E_RX_DESC_STATUS_TSYNINDX_SHIFT
@@ -580,7 +581,11 @@ enum i40e_rx_l2_ptype {
 	I40E_RX_PTYPE_L2_FCOE_VFT_FCDATA		= 18,
 	I40E_RX_PTYPE_L2_FCOE_VFT_FCRDY			= 19,
 	I40E_RX_PTYPE_L2_FCOE_VFT_FCRSP			= 20,
-	I40E_RX_PTYPE_L2_FCOE_VFT_FCOTHER	= 21
+	I40E_RX_PTYPE_L2_FCOE_VFT_FCOTHER		= 21,
+	I40E_RX_PTYPE_GRENAT4_MAC_PAY3			= 58,
+	I40E_RX_PTYPE_GRENAT4_MACVLAN_IPV6_ICMP_PAY4	= 87,
+	I40E_RX_PTYPE_GRENAT6_MAC_PAY3			= 124,
+	I40E_RX_PTYPE_GRENAT6_MACVLAN_IPV6_ICMP_PAY4	= 153
 };
 
 struct i40e_rx_ptype_decoded {