6 files changed, 144 insertions, 7 deletions

diff --git a/include/linux/netdev_features.h b/include/linux/netdev_features.h
index dcfdecbfa0b7..8c94b07e654a 100644
--- a/include/linux/netdev_features.h
+++ b/include/linux/netdev_features.h
@@ -48,8 +48,9 @@ enum {
         NETIF_F_GSO_UDP_TUNNEL_BIT,     /* ... UDP TUNNEL with TSO */
         NETIF_F_GSO_UDP_TUNNEL_CSUM_BIT,/* ... UDP TUNNEL with TSO & CSUM */
         NETIF_F_GSO_MPLS_BIT,           /* ... MPLS segmentation */
+        NETIF_F_GSO_TUNNEL_REMCSUM_BIT, /* ... TUNNEL with TSO & REMCSUM */
         /**/NETIF_F_GSO_LAST =          /* last bit, see GSO_MASK */
-                NETIF_F_GSO_MPLS_BIT,
+                NETIF_F_GSO_TUNNEL_REMCSUM_BIT,
 
         NETIF_F_FCOE_CRC_BIT,           /* FCoE CRC32 */
         NETIF_F_SCTP_CSUM_BIT,          /* SCTP checksum offload */
@@ -119,6 +120,7 @@ enum {
 #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_GSO_TUNNEL_REMCSUM __NETIF_F(GSO_TUNNEL_REMCSUM)
 #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)
 #define NETIF_F_HW_VLAN_STAG_TX __NETIF_F(HW_VLAN_STAG_TX)
diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index 5ed05bd764dc..4767f546d7c0 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -3584,6 +3584,7 @@ static inline bool net_gso_ok(netdev_features_t features, int gso_type)
         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));
+        BUILD_BUG_ON(SKB_GSO_TUNNEL_REMCSUM != (NETIF_F_GSO_TUNNEL_REMCSUM >> NETIF_F_GSO_SHIFT));
 
         return (features & feature) == feature;
 }
diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index 5ad9675b6fe1..74ed34413969 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -373,6 +373,7 @@ enum {
 
         SKB_GSO_MPLS = 1 << 12,
 
+        SKB_GSO_TUNNEL_REMCSUM = 1 << 13,
 };
 
 #if BITS_PER_LONG > 32
@@ -603,7 +604,8 @@ struct sk_buff {
 #endif
         __u8                    ipvs_property:1;
         __u8                    inner_protocol_type:1;
-        /* 4 or 6 bit hole */
+        __u8                    remcsum_offload:1;
+        /* 3 or 5 bit hole */
 
 #ifdef CONFIG_NET_SCHED
         __u16                   tc_index;       /* traffic control index */
diff --git a/include/net/fou.h b/include/net/fou.h
new file mode 100644
index 000000000000..25b26ffcf1df
--- /dev/null
+++ b/include/net/fou.h
@@ -0,0 +1,38 @@
+#ifndef __NET_FOU_H
+#define __NET_FOU_H
+
+#include <linux/skbuff.h>
+
+#include <net/flow.h>
+#include <net/gue.h>
+#include <net/ip_tunnels.h>
+#include <net/udp.h>
+
+int fou_build_header(struct sk_buff *skb, struct ip_tunnel_encap *e,
+                     u8 *protocol, struct flowi4 *fl4);
+int gue_build_header(struct sk_buff *skb, struct ip_tunnel_encap *e,
+                     u8 *protocol, struct flowi4 *fl4);
+
+static size_t fou_encap_hlen(struct ip_tunnel_encap *e)
+{
+        return sizeof(struct udphdr);
+}
+
+static size_t gue_encap_hlen(struct ip_tunnel_encap *e)
+{
+        size_t len;
+        bool need_priv = false;
+
+        len = sizeof(struct udphdr) + sizeof(struct guehdr);
+
+        if (e->flags & TUNNEL_ENCAP_FLAG_REMCSUM) {
+                len += GUE_PLEN_REMCSUM;
+                need_priv = true;
+        }
+
+        len += need_priv ? GUE_LEN_PRIV : 0;
+
+        return len;
+}
+
+#endif
diff --git a/include/net/gue.h b/include/net/gue.h
index b6c332788084..3f28ec7f1c7f 100644
--- a/include/net/gue.h
+++ b/include/net/gue.h
@@ -1,23 +1,116 @@
 #ifndef __NET_GUE_H
 #define __NET_GUE_H
 
+/* Definitions for the GUE header, standard and private flags, lengths
+ * of optional fields are below.
+ *
+ * Diagram of GUE header:
+ *
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ * |Ver|C|  Hlen   | Proto/ctype   |        Standard flags       |P|
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ * |                                                               |
+ * ~                      Fields (optional)                        ~
+ * |                                                               |
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ * |            Private flags (optional, P bit is set)             |
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ * |                                                               |
+ * ~                   Private fields (optional)                   ~
+ * |                                                               |
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ *
+ * C bit indicates contol message when set, data message when unset.
+ * For a control message, proto/ctype is interpreted as a type of
+ * control message. For data messages, proto/ctype is the IP protocol
+ * of the next header.
+ *
+ * P bit indicates private flags field is present. The private flags
+ * may refer to options placed after this field.
+ */
+
 struct guehdr {
         union {
                 struct {
 #if defined(__LITTLE_ENDIAN_BITFIELD)
-                        __u8    hlen:4,
-                        version:4;
+                        __u8    hlen:5,
+                                control:1,
+                                version:2;
 #elif defined (__BIG_ENDIAN_BITFIELD)
-                        __u8    version:4,
-                                hlen:4;
+                        __u8    version:2,
+                                control:1,
+                                hlen:5;
 #else
 #error  "Please fix <asm/byteorder.h>"
 #endif
-                        __u8    next_hdr;
+                        __u8    proto_ctype;
                         __u16   flags;
                 };
                 __u32 word;
         };
 };
 
+/* Standard flags in GUE header */
+
+#define GUE_FLAG_PRIV   htons(1<<0)     /* Private flags are in options */
+#define GUE_LEN_PRIV    4
+
+#define GUE_FLAGS_ALL   (GUE_FLAG_PRIV)
+
+/* Private flags in the private option extension */
+
+#define GUE_PFLAG_REMCSUM       htonl(1 << 31)
+#define GUE_PLEN_REMCSUM        4
+
+#define GUE_PFLAGS_ALL  (GUE_PFLAG_REMCSUM)
+
+/* Functions to compute options length corresponding to flags.
+ * If we ever have a lot of flags this can be potentially be
+ * converted to a more optimized algorithm (table lookup
+ * for instance).
+ */
+static inline size_t guehdr_flags_len(__be16 flags)
+{
+        return ((flags & GUE_FLAG_PRIV) ? GUE_LEN_PRIV : 0);
+}
+
+static inline size_t guehdr_priv_flags_len(__be32 flags)
+{
+        return 0;
+}
+
+/* Validate standard and private flags. Returns non-zero (meaning invalid)
+ * if there is an unknown standard or private flags, or the options length for
+ * the flags exceeds the options length specific in hlen of the GUE header.
+ */
+static inline int validate_gue_flags(struct guehdr *guehdr,
+                                     size_t optlen)
+{
+        size_t len;
+        __be32 flags = guehdr->flags;
+
+        if (flags & ~GUE_FLAGS_ALL)
+                return 1;
+
+        len = guehdr_flags_len(flags);
+        if (len > optlen)
+                return 1;
+
+        if (flags & GUE_FLAG_PRIV) {
+                /* Private flags are last four bytes accounted in
+                 * guehdr_flags_len
+                 */
+                flags = *(__be32 *)((void *)&guehdr[1] + len - GUE_LEN_PRIV);
+
+                if (flags & ~GUE_PFLAGS_ALL)
+                        return 1;
+
+                len += guehdr_priv_flags_len(flags);
+                if (len > optlen)
+                        return 1;
+        }
+
+        return 0;
+}
+
 #endif
diff --git a/include/uapi/linux/if_tunnel.h b/include/uapi/linux/if_tunnel.h
index 280d9e092283..bd3cc11a431f 100644
--- a/include/uapi/linux/if_tunnel.h
+++ b/include/uapi/linux/if_tunnel.h
@@ -69,6 +69,7 @@ enum tunnel_encap_types {
 
 #define TUNNEL_ENCAP_FLAG_CSUM          (1<<0)
 #define TUNNEL_ENCAP_FLAG_CSUM6         (1<<1)
+#define TUNNEL_ENCAP_FLAG_REMCSUM       (1<<2)
 
 /* SIT-mode i_flags */
 #define SIT_ISATAP      0x0001