v4.19.13 snapshot.
diff --git a/include/net/dst_ops.h b/include/net/dst_ops.h
new file mode 100644
index 0000000..5ec645f
--- /dev/null
+++ b/include/net/dst_ops.h
@@ -0,0 +1,70 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _NET_DST_OPS_H
+#define _NET_DST_OPS_H
+#include <linux/types.h>
+#include <linux/percpu_counter.h>
+#include <linux/cache.h>
+
+struct dst_entry;
+struct kmem_cachep;
+struct net_device;
+struct sk_buff;
+struct sock;
+struct net;
+
+struct dst_ops {
+ unsigned short family;
+ unsigned int gc_thresh;
+
+ int (*gc)(struct dst_ops *ops);
+ struct dst_entry * (*check)(struct dst_entry *, __u32 cookie);
+ unsigned int (*default_advmss)(const struct dst_entry *);
+ unsigned int (*mtu)(const struct dst_entry *);
+ u32 * (*cow_metrics)(struct dst_entry *, unsigned long);
+ void (*destroy)(struct dst_entry *);
+ void (*ifdown)(struct dst_entry *,
+ struct net_device *dev, int how);
+ struct dst_entry * (*negative_advice)(struct dst_entry *);
+ void (*link_failure)(struct sk_buff *);
+ void (*update_pmtu)(struct dst_entry *dst, struct sock *sk,
+ struct sk_buff *skb, u32 mtu);
+ void (*redirect)(struct dst_entry *dst, struct sock *sk,
+ struct sk_buff *skb);
+ int (*local_out)(struct net *net, struct sock *sk, struct sk_buff *skb);
+ struct neighbour * (*neigh_lookup)(const struct dst_entry *dst,
+ struct sk_buff *skb,
+ const void *daddr);
+ void (*confirm_neigh)(const struct dst_entry *dst,
+ const void *daddr);
+
+ struct kmem_cache *kmem_cachep;
+
+ struct percpu_counter pcpuc_entries ____cacheline_aligned_in_smp;
+};
+
+static inline int dst_entries_get_fast(struct dst_ops *dst)
+{
+ return percpu_counter_read_positive(&dst->pcpuc_entries);
+}
+
+static inline int dst_entries_get_slow(struct dst_ops *dst)
+{
+ return percpu_counter_sum_positive(&dst->pcpuc_entries);
+}
+
+static inline void dst_entries_add(struct dst_ops *dst, int val)
+{
+ percpu_counter_add(&dst->pcpuc_entries, val);
+}
+
+static inline int dst_entries_init(struct dst_ops *dst)
+{
+ return percpu_counter_init(&dst->pcpuc_entries, 0, GFP_KERNEL);
+}
+
+static inline void dst_entries_destroy(struct dst_ops *dst)
+{
+ percpu_counter_destroy(&dst->pcpuc_entries);
+}
+
+#endif