v4.19.13 snapshot.
diff --git a/include/net/lwtunnel.h b/include/net/lwtunnel.h
new file mode 100644
index 0000000..33fd9ba
--- /dev/null
+++ b/include/net/lwtunnel.h
@@ -0,0 +1,260 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __NET_LWTUNNEL_H
+#define __NET_LWTUNNEL_H 1
+
+#include <linux/lwtunnel.h>
+#include <linux/netdevice.h>
+#include <linux/skbuff.h>
+#include <linux/types.h>
+#include <net/route.h>
+
+#define LWTUNNEL_HASH_BITS 7
+#define LWTUNNEL_HASH_SIZE (1 << LWTUNNEL_HASH_BITS)
+
+/* lw tunnel state flags */
+#define LWTUNNEL_STATE_OUTPUT_REDIRECT BIT(0)
+#define LWTUNNEL_STATE_INPUT_REDIRECT BIT(1)
+#define LWTUNNEL_STATE_XMIT_REDIRECT BIT(2)
+
+enum {
+ LWTUNNEL_XMIT_DONE,
+ LWTUNNEL_XMIT_CONTINUE,
+};
+
+
+struct lwtunnel_state {
+ __u16 type;
+ __u16 flags;
+ __u16 headroom;
+ atomic_t refcnt;
+ int (*orig_output)(struct net *net, struct sock *sk, struct sk_buff *skb);
+ int (*orig_input)(struct sk_buff *);
+ struct rcu_head rcu;
+ __u8 data[0];
+};
+
+struct lwtunnel_encap_ops {
+ int (*build_state)(struct nlattr *encap,
+ unsigned int family, const void *cfg,
+ struct lwtunnel_state **ts,
+ struct netlink_ext_ack *extack);
+ void (*destroy_state)(struct lwtunnel_state *lws);
+ int (*output)(struct net *net, struct sock *sk, struct sk_buff *skb);
+ int (*input)(struct sk_buff *skb);
+ int (*fill_encap)(struct sk_buff *skb,
+ struct lwtunnel_state *lwtstate);
+ int (*get_encap_size)(struct lwtunnel_state *lwtstate);
+ int (*cmp_encap)(struct lwtunnel_state *a, struct lwtunnel_state *b);
+ int (*xmit)(struct sk_buff *skb);
+
+ struct module *owner;
+};
+
+#ifdef CONFIG_LWTUNNEL
+void lwtstate_free(struct lwtunnel_state *lws);
+
+static inline struct lwtunnel_state *
+lwtstate_get(struct lwtunnel_state *lws)
+{
+ if (lws)
+ atomic_inc(&lws->refcnt);
+
+ return lws;
+}
+
+static inline void lwtstate_put(struct lwtunnel_state *lws)
+{
+ if (!lws)
+ return;
+
+ if (atomic_dec_and_test(&lws->refcnt))
+ lwtstate_free(lws);
+}
+
+static inline bool lwtunnel_output_redirect(struct lwtunnel_state *lwtstate)
+{
+ if (lwtstate && (lwtstate->flags & LWTUNNEL_STATE_OUTPUT_REDIRECT))
+ return true;
+
+ return false;
+}
+
+static inline bool lwtunnel_input_redirect(struct lwtunnel_state *lwtstate)
+{
+ if (lwtstate && (lwtstate->flags & LWTUNNEL_STATE_INPUT_REDIRECT))
+ return true;
+
+ return false;
+}
+
+static inline bool lwtunnel_xmit_redirect(struct lwtunnel_state *lwtstate)
+{
+ if (lwtstate && (lwtstate->flags & LWTUNNEL_STATE_XMIT_REDIRECT))
+ return true;
+
+ return false;
+}
+
+static inline unsigned int lwtunnel_headroom(struct lwtunnel_state *lwtstate,
+ unsigned int mtu)
+{
+ if ((lwtunnel_xmit_redirect(lwtstate) ||
+ lwtunnel_output_redirect(lwtstate)) && lwtstate->headroom < mtu)
+ return lwtstate->headroom;
+
+ return 0;
+}
+
+int lwtunnel_encap_add_ops(const struct lwtunnel_encap_ops *op,
+ unsigned int num);
+int lwtunnel_encap_del_ops(const struct lwtunnel_encap_ops *op,
+ unsigned int num);
+int lwtunnel_valid_encap_type(u16 encap_type,
+ struct netlink_ext_ack *extack);
+int lwtunnel_valid_encap_type_attr(struct nlattr *attr, int len,
+ struct netlink_ext_ack *extack);
+int lwtunnel_build_state(u16 encap_type,
+ struct nlattr *encap,
+ unsigned int family, const void *cfg,
+ struct lwtunnel_state **lws,
+ struct netlink_ext_ack *extack);
+int lwtunnel_fill_encap(struct sk_buff *skb,
+ struct lwtunnel_state *lwtstate);
+int lwtunnel_get_encap_size(struct lwtunnel_state *lwtstate);
+struct lwtunnel_state *lwtunnel_state_alloc(int hdr_len);
+int lwtunnel_cmp_encap(struct lwtunnel_state *a, struct lwtunnel_state *b);
+int lwtunnel_output(struct net *net, struct sock *sk, struct sk_buff *skb);
+int lwtunnel_input(struct sk_buff *skb);
+int lwtunnel_xmit(struct sk_buff *skb);
+
+static inline void lwtunnel_set_redirect(struct dst_entry *dst)
+{
+ if (lwtunnel_output_redirect(dst->lwtstate)) {
+ dst->lwtstate->orig_output = dst->output;
+ dst->output = lwtunnel_output;
+ }
+ if (lwtunnel_input_redirect(dst->lwtstate)) {
+ dst->lwtstate->orig_input = dst->input;
+ dst->input = lwtunnel_input;
+ }
+}
+#else
+
+static inline void lwtstate_free(struct lwtunnel_state *lws)
+{
+}
+
+static inline struct lwtunnel_state *
+lwtstate_get(struct lwtunnel_state *lws)
+{
+ return lws;
+}
+
+static inline void lwtstate_put(struct lwtunnel_state *lws)
+{
+}
+
+static inline bool lwtunnel_output_redirect(struct lwtunnel_state *lwtstate)
+{
+ return false;
+}
+
+static inline bool lwtunnel_input_redirect(struct lwtunnel_state *lwtstate)
+{
+ return false;
+}
+
+static inline bool lwtunnel_xmit_redirect(struct lwtunnel_state *lwtstate)
+{
+ return false;
+}
+
+static inline void lwtunnel_set_redirect(struct dst_entry *dst)
+{
+}
+
+static inline unsigned int lwtunnel_headroom(struct lwtunnel_state *lwtstate,
+ unsigned int mtu)
+{
+ return 0;
+}
+
+static inline int lwtunnel_encap_add_ops(const struct lwtunnel_encap_ops *op,
+ unsigned int num)
+{
+ return -EOPNOTSUPP;
+
+}
+
+static inline int lwtunnel_encap_del_ops(const struct lwtunnel_encap_ops *op,
+ unsigned int num)
+{
+ return -EOPNOTSUPP;
+}
+
+static inline int lwtunnel_valid_encap_type(u16 encap_type,
+ struct netlink_ext_ack *extack)
+{
+ NL_SET_ERR_MSG(extack, "CONFIG_LWTUNNEL is not enabled in this kernel");
+ return -EOPNOTSUPP;
+}
+static inline int lwtunnel_valid_encap_type_attr(struct nlattr *attr, int len,
+ struct netlink_ext_ack *extack)
+{
+ /* return 0 since we are not walking attr looking for
+ * RTA_ENCAP_TYPE attribute on nexthops.
+ */
+ return 0;
+}
+
+static inline int lwtunnel_build_state(u16 encap_type,
+ struct nlattr *encap,
+ unsigned int family, const void *cfg,
+ struct lwtunnel_state **lws,
+ struct netlink_ext_ack *extack)
+{
+ return -EOPNOTSUPP;
+}
+
+static inline int lwtunnel_fill_encap(struct sk_buff *skb,
+ struct lwtunnel_state *lwtstate)
+{
+ return 0;
+}
+
+static inline int lwtunnel_get_encap_size(struct lwtunnel_state *lwtstate)
+{
+ return 0;
+}
+
+static inline struct lwtunnel_state *lwtunnel_state_alloc(int hdr_len)
+{
+ return NULL;
+}
+
+static inline int lwtunnel_cmp_encap(struct lwtunnel_state *a,
+ struct lwtunnel_state *b)
+{
+ return 0;
+}
+
+static inline int lwtunnel_output(struct net *net, struct sock *sk, struct sk_buff *skb)
+{
+ return -EOPNOTSUPP;
+}
+
+static inline int lwtunnel_input(struct sk_buff *skb)
+{
+ return -EOPNOTSUPP;
+}
+
+static inline int lwtunnel_xmit(struct sk_buff *skb)
+{
+ return -EOPNOTSUPP;
+}
+
+#endif /* CONFIG_LWTUNNEL */
+
+#define MODULE_ALIAS_RTNL_LWT(encap_type) MODULE_ALIAS("rtnl-lwt-" __stringify(encap_type))
+
+#endif /* __NET_LWTUNNEL_H */