net/ip_tunnels: Introduce tunnel_id_to_key32() and key32_to_tunnel_id()

Add utility functions to convert a 32 bits key into a 64 bits tunnel and
vice versa.
These functions will be used instead of cloning code in GRE and VXLAN,
and in tc act_iptunnel which will be introduced in a following patch in
this patchset.

Signed-off-by: Amir Vadai <[e-mail]>
Signed-off-by: Hadar Hen Zion <[e-mail]>
Reviewed-by: Shmulik Ladkani <[e-mail]>
Acked-by: Jiri Benc <[e-mail]>
Acked-by: Jiri Pirko <[e-mail]>
Signed-off-by: David S. Miller <[e-mail]>

drivers/net/vxlan.c

···
 		struct metadata_dst *tun_dst;
 
 		tun_dst = udp_tun_rx_dst(skb, vxlan_get_sk_family(vs), TUNNEL_KEY,
-					 vxlan_vni_to_tun_id(vni), sizeof(*md));
+					 key32_to_tunnel_id(vni), sizeof(*md));
 
 		if (!tun_dst)
 			goto drop;
···
 			goto drop;
 		}
 		dst_port = info->key.tp_dst ? : vxlan->cfg.dst_port;
-		vni = vxlan_tun_id_to_vni(info->key.tun_id);
+		vni = tunnel_id_to_key32(info->key.tun_id);
 		remote_ip.sa.sa_family = ip_tunnel_info_af(info);
 		if (remote_ip.sa.sa_family == AF_INET) {
 			remote_ip.sin.sin_addr.s_addr = info->key.u.ipv4.dst;

include/net/ip_tunnels.h

···
 	return tun_info->mode & IP_TUNNEL_INFO_IPV6 ? AF_INET6 : AF_INET;
 }
 
+static inline __be64 key32_to_tunnel_id(__be32 key)
+{
+#ifdef __BIG_ENDIAN
+	return (__force __be64)key;
+#else
+	return (__force __be64)((__force u64)key << 32);
+#endif
+}
+
+/* Returns the least-significant 32 bits of a __be64. */
+static inline __be32 tunnel_id_to_key32(__be64 tun_id)
+{
+#ifdef __BIG_ENDIAN
+	return (__force __be32)tun_id;
+#else
+	return (__force __be32)((__force u64)tun_id >> 32);
+#endif
+}
+
 #ifdef CONFIG_INET
 
 int ip_tunnel_init(struct net_device *dev);

include/net/vxlan.h

···
 #endif
 }
 
-static inline __be32 vxlan_tun_id_to_vni(__be64 tun_id)
-{
-#if defined(__BIG_ENDIAN)
-	return (__force __be32)tun_id;
-#else
-	return (__force __be32)((__force u64)tun_id >> 32);
-#endif
-}
-
-static inline __be64 vxlan_vni_to_tun_id(__be32 vni)
-{
-#if defined(__BIG_ENDIAN)
-	return (__force __be64)vni;
-#else
-	return (__force __be64)((u64)(__force u32)vni << 32);
-#endif
-}
-
 static inline size_t vxlan_rco_start(__be32 vni_field)
 {
 	return be32_to_cpu(vni_field & VXLAN_RCO_MASK) << VXLAN_RCO_SHIFT;

net/ipv4/ip_gre.c

···
 	ipgre_err(skb, info, &tpi);
 }
 
-static __be64 key_to_tunnel_id(__be32 key)
-{
-#ifdef __BIG_ENDIAN
-	return (__force __be64)((__force u32)key);
-#else
-	return (__force __be64)((__force u64)key << 32);
-#endif
-}
-
-/* Returns the least-significant 32 bits of a __be64. */
-static __be32 tunnel_id_to_key(__be64 x)
-{
-#ifdef __BIG_ENDIAN
-	return (__force __be32)x;
-#else
-	return (__force __be32)((__force u64)x >> 32);
-#endif
-}
-
 static int __ipgre_rcv(struct sk_buff *skb, const struct tnl_ptk_info *tpi,
 		       struct ip_tunnel_net *itn, int hdr_len, bool raw_proto)
 {
···
 			__be64 tun_id;
 
 			flags = tpi->flags & (TUNNEL_CSUM | TUNNEL_KEY);
-			tun_id = key_to_tunnel_id(tpi->key);
+			tun_id = key32_to_tunnel_id(tpi->key);
 			tun_dst = ip_tun_rx_dst(skb, flags, tun_id, 0);
 			if (!tun_dst)
 				return PACKET_REJECT;
···
 
 	flags = tun_info->key.tun_flags & (TUNNEL_CSUM | TUNNEL_KEY);
 	gre_build_header(skb, tunnel_hlen, flags, proto,
-			 tunnel_id_to_key(tun_info->key.tun_id), 0);
+			 tunnel_id_to_key32(tun_info->key.tun_id), 0);
 
 	df = key->tun_flags & TUNNEL_DONT_FRAGMENT ?  htons(IP_DF) : 0;