vxlan: keep flags and vni in network byte order

Prevent repeated conversions from and to network order in the fast path.

To achieve this, define all flag constants in big endian order and store VNI
as __be32. To prevent confusion between the actual VNI value and the VNI
field from the header (which contains additional reserved byte), strictly
distinguish between "vni" and "vni_field".
Signed-off-by: Jiri Benc <jbenc@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/net/vxlan.h

@@ -24,11 +24,11 @@ struct vxlanhdr {
 };
 
 /* VXLAN header flags. */
-#define VXLAN_HF_VNI BIT(27)
+#define VXLAN_HF_VNI	cpu_to_be32(BIT(27))
 
 #define VXLAN_N_VID     (1u << 24)
 #define VXLAN_VID_MASK  (VXLAN_N_VID - 1)
-#define VXLAN_VNI_MASK  (VXLAN_VID_MASK << 8)
+#define VXLAN_VNI_MASK	cpu_to_be32(VXLAN_VID_MASK << 8)
 #define VXLAN_HLEN (sizeof(struct udphdr) + sizeof(struct vxlanhdr))
 
 #define VNI_HASH_BITS	10
@@ -55,14 +55,14 @@ struct vxlanhdr {
  */
 
 /* VXLAN-RCO header flags. */
-#define VXLAN_HF_RCO BIT(21)
+#define VXLAN_HF_RCO	cpu_to_be32(BIT(21))
 
 /* Remote checksum offload header option */
-#define VXLAN_RCO_MASK  0x7f    /* Last byte of vni field */
-#define VXLAN_RCO_UDP   0x80    /* Indicate UDP RCO (TCP when not set *) */
-#define VXLAN_RCO_SHIFT 1       /* Left shift of start */
+#define VXLAN_RCO_MASK	cpu_to_be32(0x7f)  /* Last byte of vni field */
+#define VXLAN_RCO_UDP	cpu_to_be32(0x80)  /* Indicate UDP RCO (TCP when not set *) */
+#define VXLAN_RCO_SHIFT	1		   /* Left shift of start */
 #define VXLAN_RCO_SHIFT_MASK ((1 << VXLAN_RCO_SHIFT) - 1)
-#define VXLAN_MAX_REMCSUM_START (VXLAN_RCO_MASK << VXLAN_RCO_SHIFT)
+#define VXLAN_MAX_REMCSUM_START (0x7f << VXLAN_RCO_SHIFT)
 
 /*
  * VXLAN Group Based Policy Extension (VXLAN_F_GBP):
@@ -105,9 +105,9 @@ struct vxlanhdr_gbp {
 };
 
 /* VXLAN-GBP header flags. */
-#define VXLAN_HF_GBP BIT(31)
+#define VXLAN_HF_GBP	cpu_to_be32(BIT(31))
 
-#define VXLAN_GBP_USED_BITS (VXLAN_HF_GBP | 0xFFFFFF)
+#define VXLAN_GBP_USED_BITS (VXLAN_HF_GBP | cpu_to_be32(0xFFFFFF))
 
 /* skb->mark mapping
  *
@@ -144,7 +144,7 @@ union vxlan_addr {
 struct vxlan_rdst {
 	union vxlan_addr	 remote_ip;
 	__be16			 remote_port;
-	u32			 remote_vni;
+	__be32			 remote_vni;
 	u32			 remote_ifindex;
 	struct list_head	 list;
 	struct rcu_head		 rcu;
@@ -154,7 +154,7 @@ struct vxlan_rdst {
 struct vxlan_config {
 	union vxlan_addr	remote_ip;
 	union vxlan_addr	saddr;
-	u32			vni;
+	__be32			vni;
 	int			remote_ifindex;
 	int			mtu;
 	__be16			dst_port;
@@ -267,6 +267,54 @@ static inline struct vxlanhdr *vxlan_hdr(struct sk_buff *skb)
 	return (struct vxlanhdr *)(udp_hdr(skb) + 1);
 }
 
+static inline __be32 vxlan_vni(__be32 vni_field)
+{
+#if defined(__BIG_ENDIAN)
+	return vni_field >> 8;
+#else
+	return (vni_field & VXLAN_VNI_MASK) << 8;
+#endif
+}
+
+static inline __be32 vxlan_vni_field(__be32 vni)
+{
+#if defined(__BIG_ENDIAN)
+	return vni << 8;
+#else
+	return vni >> 8;
+#endif
+}
+
+static inline __be32 vxlan_tun_id_to_vni(__be64 tun_id)
+{
+#if defined(__BIG_ENDIAN)
+	return tun_id;
+#else
+	return tun_id >> 32;
+#endif
+}
+
+static inline size_t vxlan_rco_start(__be32 vni_field)
+{
+	return be32_to_cpu(vni_field & VXLAN_RCO_MASK) << VXLAN_RCO_SHIFT;
+}
+
+static inline size_t vxlan_rco_offset(__be32 vni_field)
+{
+	return (vni_field & VXLAN_RCO_UDP) ?
+		offsetof(struct udphdr, check) :
+		offsetof(struct tcphdr, check);
+}
+
+static inline __be32 vxlan_compute_rco(unsigned int start, unsigned int offset)
+{
+	__be32 vni_field = cpu_to_be32(start >> VXLAN_RCO_SHIFT);
+
+	if (offset == offsetof(struct udphdr, check))
+		vni_field |= VXLAN_RCO_UDP;
+	return vni_field;
+}
+
 #if IS_ENABLED(CONFIG_VXLAN)
 void vxlan_get_rx_port(struct net_device *netdev);
 #else