Merge branch 'csum_fixes'

Tom Herbert says:

====================
Fixes related to some recent checksum modifications.

- Fix GSO constants to match NETIF flags
- Fix logic in saving checksum complete in __skb_checksum_complete
- Call __skb_checksum_complete from UDP if we are checksumming over
  whole packet in order to save checksum.
- Fixes to VXLAN to work correctly with checksum complete
====================
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/vxlan.c

@@ -1156,15 +1156,7 @@ static int vxlan_udp_encap_recv(struct sock *sk, struct sk_buff *skb)
 	if (!vs)
 		goto drop;
 
-	/* If the NIC driver gave us an encapsulated packet
-	 * with the encapsulation mark, the device checksummed it
-	 * for us. Otherwise force the upper layers to verify it.
-	 */
-	if ((skb->ip_summed != CHECKSUM_UNNECESSARY && skb->ip_summed != CHECKSUM_PARTIAL) ||
-	    !skb->encapsulation)
-		skb->ip_summed = CHECKSUM_NONE;
-
-	skb->encapsulation = 0;
+	skb_pop_rcv_encapsulation(skb);
 
 	vs->rcv(vs, skb, vxh->vx_vni);
 	return 0;
@@ -1201,6 +1193,7 @@ static void vxlan_rcv(struct vxlan_sock *vs,
 	skb_reset_mac_header(skb);
 	skb_scrub_packet(skb, !net_eq(vxlan->net, dev_net(vxlan->dev)));
 	skb->protocol = eth_type_trans(skb, vxlan->dev);
+	skb_postpull_rcsum(skb, eth_hdr(skb), ETH_HLEN);
 
 	/* Ignore packet loops (and multicast echo) */
 	if (ether_addr_equal(eth_hdr(skb)->h_source, vxlan->dev->dev_addr))

include/linux/netdev_features.h

@@ -117,6 +117,7 @@ enum {
 #define NETIF_F_GSO_IPIP	__NETIF_F(GSO_IPIP)
 #define NETIF_F_GSO_SIT		__NETIF_F(GSO_SIT)
 #define NETIF_F_GSO_UDP_TUNNEL	__NETIF_F(GSO_UDP_TUNNEL)
+#define NETIF_F_GSO_UDP_TUNNEL_CSUM __NETIF_F(GSO_UDP_TUNNEL_CSUM)
 #define NETIF_F_GSO_MPLS	__NETIF_F(GSO_MPLS)
 #define NETIF_F_HW_VLAN_STAG_FILTER __NETIF_F(HW_VLAN_STAG_FILTER)
 #define NETIF_F_HW_VLAN_STAG_RX	__NETIF_F(HW_VLAN_STAG_RX)

include/linux/netdevice.h

@@ -3305,6 +3305,13 @@ static inline bool net_gso_ok(netdev_features_t features, int gso_type)
 	BUILD_BUG_ON(SKB_GSO_TCP_ECN != (NETIF_F_TSO_ECN >> NETIF_F_GSO_SHIFT));
 	BUILD_BUG_ON(SKB_GSO_TCPV6   != (NETIF_F_TSO6 >> NETIF_F_GSO_SHIFT));
 	BUILD_BUG_ON(SKB_GSO_FCOE    != (NETIF_F_FSO >> NETIF_F_GSO_SHIFT));
+	BUILD_BUG_ON(SKB_GSO_GRE     != (NETIF_F_GSO_GRE >> NETIF_F_GSO_SHIFT));
+	BUILD_BUG_ON(SKB_GSO_GRE_CSUM != (NETIF_F_GSO_GRE_CSUM >> NETIF_F_GSO_SHIFT));
+	BUILD_BUG_ON(SKB_GSO_IPIP    != (NETIF_F_GSO_IPIP >> NETIF_F_GSO_SHIFT));
+	BUILD_BUG_ON(SKB_GSO_SIT     != (NETIF_F_GSO_SIT >> NETIF_F_GSO_SHIFT));
+	BUILD_BUG_ON(SKB_GSO_UDP_TUNNEL != (NETIF_F_GSO_UDP_TUNNEL >> NETIF_F_GSO_SHIFT));
+	BUILD_BUG_ON(SKB_GSO_UDP_TUNNEL_CSUM != (NETIF_F_GSO_UDP_TUNNEL_CSUM >> NETIF_F_GSO_SHIFT));
+	BUILD_BUG_ON(SKB_GSO_MPLS    != (NETIF_F_GSO_MPLS >> NETIF_F_GSO_SHIFT));
 
 	return (features & feature) == feature;
 }

include/linux/skbuff.h

@@ -338,17 +338,18 @@ enum {
 
 	SKB_GSO_GRE = 1 << 6,
 
-	SKB_GSO_IPIP = 1 << 7,
+	SKB_GSO_GRE_CSUM = 1 << 7,
 
-	SKB_GSO_SIT = 1 << 8,
+	SKB_GSO_IPIP = 1 << 8,
 
-	SKB_GSO_UDP_TUNNEL = 1 << 9,
+	SKB_GSO_SIT = 1 << 9,
 
-	SKB_GSO_MPLS = 1 << 10,
+	SKB_GSO_UDP_TUNNEL = 1 << 10,
 
 	SKB_GSO_UDP_TUNNEL_CSUM = 1 << 11,
 
-	SKB_GSO_GRE_CSUM = 1 << 12,
+	SKB_GSO_MPLS = 1 << 12,
+
 };
 
 #if BITS_PER_LONG > 32
@@ -1853,6 +1854,18 @@ static inline int pskb_network_may_pull(struct sk_buff *skb, unsigned int len)
 	return pskb_may_pull(skb, skb_network_offset(skb) + len);
 }
 
+static inline void skb_pop_rcv_encapsulation(struct sk_buff *skb)
+{
+	/* Only continue with checksum unnecessary if device indicated
+	 * it is valid across encapsulation (skb->encapsulation was set).
+	 */
+	if (skb->ip_summed == CHECKSUM_UNNECESSARY && !skb->encapsulation)
+		skb->ip_summed = CHECKSUM_NONE;
+
+	skb->encapsulation = 0;
+	skb->csum_valid = 0;
+}
+
 /*
  * CPUs often take a performance hit when accessing unaligned memory
  * locations. The actual performance hit varies, it can be small if the

include/net/udp.h

@@ -111,7 +111,9 @@ struct sk_buff;
  */
 static inline __sum16 __udp_lib_checksum_complete(struct sk_buff *skb)
 {
-	return __skb_checksum_complete_head(skb, UDP_SKB_CB(skb)->cscov);
+	return (UDP_SKB_CB(skb)->cscov == skb->len ?
+		__skb_checksum_complete(skb) :
+		__skb_checksum_complete_head(skb, UDP_SKB_CB(skb)->cscov));
 }
 
 static inline int udp_lib_checksum_complete(struct sk_buff *skb)

net/core/datagram.c

@@ -739,22 +739,38 @@ __sum16 __skb_checksum_complete_head(struct sk_buff *skb, int len)
 	__sum16 sum;
 
 	sum = csum_fold(skb_checksum(skb, 0, len, skb->csum));
-	if (unlikely(skb->ip_summed == CHECKSUM_COMPLETE) && !sum &&
+	if (likely(!sum)) {
+		if (unlikely(skb->ip_summed == CHECKSUM_COMPLETE) &&
 		    !skb->csum_complete_sw)
 			netdev_rx_csum_fault(skb->dev);
-
-	/* Save checksum complete for later use */
-	skb->csum = sum;
-	skb->ip_summed = CHECKSUM_COMPLETE;
-	skb->csum_complete_sw = 1;
-
+	}
+	skb->csum_valid = !sum;
 	return sum;
 }
 EXPORT_SYMBOL(__skb_checksum_complete_head);
 
 __sum16 __skb_checksum_complete(struct sk_buff *skb)
 {
-	return __skb_checksum_complete_head(skb, skb->len);
+	__wsum csum;
+	__sum16 sum;
+
+	csum = skb_checksum(skb, 0, skb->len, 0);
+
+	/* skb->csum holds pseudo checksum */
+	sum = csum_fold(csum_add(skb->csum, csum));
+	if (likely(!sum)) {
+		if (unlikely(skb->ip_summed == CHECKSUM_COMPLETE) &&
+		    !skb->csum_complete_sw)
+			netdev_rx_csum_fault(skb->dev);
+	}
+
+	/* Save full packet checksum */
+	skb->csum = csum;
+	skb->ip_summed = CHECKSUM_COMPLETE;
+	skb->csum_complete_sw = 1;
+	skb->csum_valid = !sum;
+
+	return sum;
 }
 EXPORT_SYMBOL(__skb_checksum_complete);
 

net/core/skbuff.c

@@ -689,6 +689,9 @@ static void __copy_skb_header(struct sk_buff *new, const struct sk_buff *old)
 	new->ooo_okay		= old->ooo_okay;
 	new->no_fcs		= old->no_fcs;
 	new->encapsulation	= old->encapsulation;
+	new->encap_hdr_csum	= old->encap_hdr_csum;
+	new->csum_valid		= old->csum_valid;
+	new->csum_complete_sw	= old->csum_complete_sw;
 #ifdef CONFIG_XFRM
 	new->sp			= secpath_get(old->sp);
 #endif