v4.19.13 snapshot.
diff --git a/include/net/dst.h b/include/net/dst.h
new file mode 100644
index 0000000..6cf0870
--- /dev/null
+++ b/include/net/dst.h
@@ -0,0 +1,540 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * net/dst.h Protocol independent destination cache definitions.
+ *
+ * Authors: Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
+ *
+ */
+
+#ifndef _NET_DST_H
+#define _NET_DST_H
+
+#include <net/dst_ops.h>
+#include <linux/netdevice.h>
+#include <linux/rtnetlink.h>
+#include <linux/rcupdate.h>
+#include <linux/bug.h>
+#include <linux/jiffies.h>
+#include <linux/refcount.h>
+#include <net/neighbour.h>
+#include <asm/processor.h>
+
+#define DST_GC_MIN (HZ/10)
+#define DST_GC_INC (HZ/2)
+#define DST_GC_MAX (120*HZ)
+
+/* Each dst_entry has reference count and sits in some parent list(s).
+ * When it is removed from parent list, it is "freed" (dst_free).
+ * After this it enters dead state (dst->obsolete > 0) and if its refcnt
+ * is zero, it can be destroyed immediately, otherwise it is added
+ * to gc list and garbage collector periodically checks the refcnt.
+ */
+
+struct sk_buff;
+
+struct dst_entry {
+ struct net_device *dev;
+ struct dst_ops *ops;
+ unsigned long _metrics;
+ unsigned long expires;
+#ifdef CONFIG_XFRM
+ struct xfrm_state *xfrm;
+#else
+ void *__pad1;
+#endif
+ int (*input)(struct sk_buff *);
+ int (*output)(struct net *net, struct sock *sk, struct sk_buff *skb);
+
+ unsigned short flags;
+#define DST_HOST 0x0001
+#define DST_NOXFRM 0x0002
+#define DST_NOPOLICY 0x0004
+#define DST_NOCOUNT 0x0008
+#define DST_FAKE_RTABLE 0x0010
+#define DST_XFRM_TUNNEL 0x0020
+#define DST_XFRM_QUEUE 0x0040
+#define DST_METADATA 0x0080
+
+ /* A non-zero value of dst->obsolete forces by-hand validation
+ * of the route entry. Positive values are set by the generic
+ * dst layer to indicate that the entry has been forcefully
+ * destroyed.
+ *
+ * Negative values are used by the implementation layer code to
+ * force invocation of the dst_ops->check() method.
+ */
+ short obsolete;
+#define DST_OBSOLETE_NONE 0
+#define DST_OBSOLETE_DEAD 2
+#define DST_OBSOLETE_FORCE_CHK -1
+#define DST_OBSOLETE_KILL -2
+ unsigned short header_len; /* more space at head required */
+ unsigned short trailer_len; /* space to reserve at tail */
+
+ /*
+ * __refcnt wants to be on a different cache line from
+ * input/output/ops or performance tanks badly
+ */
+#ifdef CONFIG_64BIT
+ atomic_t __refcnt; /* 64-bit offset 64 */
+#endif
+ int __use;
+ unsigned long lastuse;
+ struct lwtunnel_state *lwtstate;
+ struct rcu_head rcu_head;
+ short error;
+ short __pad;
+ __u32 tclassid;
+#ifndef CONFIG_64BIT
+ atomic_t __refcnt; /* 32-bit offset 64 */
+#endif
+};
+
+struct dst_metrics {
+ u32 metrics[RTAX_MAX];
+ refcount_t refcnt;
+};
+extern const struct dst_metrics dst_default_metrics;
+
+u32 *dst_cow_metrics_generic(struct dst_entry *dst, unsigned long old);
+
+#define DST_METRICS_READ_ONLY 0x1UL
+#define DST_METRICS_REFCOUNTED 0x2UL
+#define DST_METRICS_FLAGS 0x3UL
+#define __DST_METRICS_PTR(Y) \
+ ((u32 *)((Y) & ~DST_METRICS_FLAGS))
+#define DST_METRICS_PTR(X) __DST_METRICS_PTR((X)->_metrics)
+
+static inline bool dst_metrics_read_only(const struct dst_entry *dst)
+{
+ return dst->_metrics & DST_METRICS_READ_ONLY;
+}
+
+void __dst_destroy_metrics_generic(struct dst_entry *dst, unsigned long old);
+
+static inline void dst_destroy_metrics_generic(struct dst_entry *dst)
+{
+ unsigned long val = dst->_metrics;
+ if (!(val & DST_METRICS_READ_ONLY))
+ __dst_destroy_metrics_generic(dst, val);
+}
+
+static inline u32 *dst_metrics_write_ptr(struct dst_entry *dst)
+{
+ unsigned long p = dst->_metrics;
+
+ BUG_ON(!p);
+
+ if (p & DST_METRICS_READ_ONLY)
+ return dst->ops->cow_metrics(dst, p);
+ return __DST_METRICS_PTR(p);
+}
+
+/* This may only be invoked before the entry has reached global
+ * visibility.
+ */
+static inline void dst_init_metrics(struct dst_entry *dst,
+ const u32 *src_metrics,
+ bool read_only)
+{
+ dst->_metrics = ((unsigned long) src_metrics) |
+ (read_only ? DST_METRICS_READ_ONLY : 0);
+}
+
+static inline void dst_copy_metrics(struct dst_entry *dest, const struct dst_entry *src)
+{
+ u32 *dst_metrics = dst_metrics_write_ptr(dest);
+
+ if (dst_metrics) {
+ u32 *src_metrics = DST_METRICS_PTR(src);
+
+ memcpy(dst_metrics, src_metrics, RTAX_MAX * sizeof(u32));
+ }
+}
+
+static inline u32 *dst_metrics_ptr(struct dst_entry *dst)
+{
+ return DST_METRICS_PTR(dst);
+}
+
+static inline u32
+dst_metric_raw(const struct dst_entry *dst, const int metric)
+{
+ u32 *p = DST_METRICS_PTR(dst);
+
+ return p[metric-1];
+}
+
+static inline u32
+dst_metric(const struct dst_entry *dst, const int metric)
+{
+ WARN_ON_ONCE(metric == RTAX_HOPLIMIT ||
+ metric == RTAX_ADVMSS ||
+ metric == RTAX_MTU);
+ return dst_metric_raw(dst, metric);
+}
+
+static inline u32
+dst_metric_advmss(const struct dst_entry *dst)
+{
+ u32 advmss = dst_metric_raw(dst, RTAX_ADVMSS);
+
+ if (!advmss)
+ advmss = dst->ops->default_advmss(dst);
+
+ return advmss;
+}
+
+static inline void dst_metric_set(struct dst_entry *dst, int metric, u32 val)
+{
+ u32 *p = dst_metrics_write_ptr(dst);
+
+ if (p)
+ p[metric-1] = val;
+}
+
+/* Kernel-internal feature bits that are unallocated in user space. */
+#define DST_FEATURE_ECN_CA (1 << 31)
+
+#define DST_FEATURE_MASK (DST_FEATURE_ECN_CA)
+#define DST_FEATURE_ECN_MASK (DST_FEATURE_ECN_CA | RTAX_FEATURE_ECN)
+
+static inline u32
+dst_feature(const struct dst_entry *dst, u32 feature)
+{
+ return dst_metric(dst, RTAX_FEATURES) & feature;
+}
+
+static inline u32 dst_mtu(const struct dst_entry *dst)
+{
+ return dst->ops->mtu(dst);
+}
+
+/* RTT metrics are stored in milliseconds for user ABI, but used as jiffies */
+static inline unsigned long dst_metric_rtt(const struct dst_entry *dst, int metric)
+{
+ return msecs_to_jiffies(dst_metric(dst, metric));
+}
+
+static inline u32
+dst_allfrag(const struct dst_entry *dst)
+{
+ int ret = dst_feature(dst, RTAX_FEATURE_ALLFRAG);
+ return ret;
+}
+
+static inline int
+dst_metric_locked(const struct dst_entry *dst, int metric)
+{
+ return dst_metric(dst, RTAX_LOCK) & (1<<metric);
+}
+
+static inline void dst_hold(struct dst_entry *dst)
+{
+ /*
+ * If your kernel compilation stops here, please check
+ * the placement of __refcnt in struct dst_entry
+ */
+ BUILD_BUG_ON(offsetof(struct dst_entry, __refcnt) & 63);
+ WARN_ON(atomic_inc_not_zero(&dst->__refcnt) == 0);
+}
+
+static inline void dst_use_noref(struct dst_entry *dst, unsigned long time)
+{
+ if (unlikely(time != dst->lastuse)) {
+ dst->__use++;
+ dst->lastuse = time;
+ }
+}
+
+static inline void dst_hold_and_use(struct dst_entry *dst, unsigned long time)
+{
+ dst_hold(dst);
+ dst_use_noref(dst, time);
+}
+
+static inline struct dst_entry *dst_clone(struct dst_entry *dst)
+{
+ if (dst)
+ dst_hold(dst);
+ return dst;
+}
+
+void dst_release(struct dst_entry *dst);
+
+void dst_release_immediate(struct dst_entry *dst);
+
+static inline void refdst_drop(unsigned long refdst)
+{
+ if (!(refdst & SKB_DST_NOREF))
+ dst_release((struct dst_entry *)(refdst & SKB_DST_PTRMASK));
+}
+
+/**
+ * skb_dst_drop - drops skb dst
+ * @skb: buffer
+ *
+ * Drops dst reference count if a reference was taken.
+ */
+static inline void skb_dst_drop(struct sk_buff *skb)
+{
+ if (skb->_skb_refdst) {
+ refdst_drop(skb->_skb_refdst);
+ skb->_skb_refdst = 0UL;
+ }
+}
+
+static inline void __skb_dst_copy(struct sk_buff *nskb, unsigned long refdst)
+{
+ nskb->_skb_refdst = refdst;
+ if (!(nskb->_skb_refdst & SKB_DST_NOREF))
+ dst_clone(skb_dst(nskb));
+}
+
+static inline void skb_dst_copy(struct sk_buff *nskb, const struct sk_buff *oskb)
+{
+ __skb_dst_copy(nskb, oskb->_skb_refdst);
+}
+
+/**
+ * dst_hold_safe - Take a reference on a dst if possible
+ * @dst: pointer to dst entry
+ *
+ * This helper returns false if it could not safely
+ * take a reference on a dst.
+ */
+static inline bool dst_hold_safe(struct dst_entry *dst)
+{
+ return atomic_inc_not_zero(&dst->__refcnt);
+}
+
+/**
+ * skb_dst_force - makes sure skb dst is refcounted
+ * @skb: buffer
+ *
+ * If dst is not yet refcounted and not destroyed, grab a ref on it.
+ */
+static inline void skb_dst_force(struct sk_buff *skb)
+{
+ if (skb_dst_is_noref(skb)) {
+ struct dst_entry *dst = skb_dst(skb);
+
+ WARN_ON(!rcu_read_lock_held());
+ if (!dst_hold_safe(dst))
+ dst = NULL;
+
+ skb->_skb_refdst = (unsigned long)dst;
+ }
+}
+
+
+/**
+ * __skb_tunnel_rx - prepare skb for rx reinsert
+ * @skb: buffer
+ * @dev: tunnel device
+ * @net: netns for packet i/o
+ *
+ * After decapsulation, packet is going to re-enter (netif_rx()) our stack,
+ * so make some cleanups. (no accounting done)
+ */
+static inline void __skb_tunnel_rx(struct sk_buff *skb, struct net_device *dev,
+ struct net *net)
+{
+ skb->dev = dev;
+
+ /*
+ * Clear hash so that we can recalulate the hash for the
+ * encapsulated packet, unless we have already determine the hash
+ * over the L4 4-tuple.
+ */
+ skb_clear_hash_if_not_l4(skb);
+ skb_set_queue_mapping(skb, 0);
+ skb_scrub_packet(skb, !net_eq(net, dev_net(dev)));
+}
+
+/**
+ * skb_tunnel_rx - prepare skb for rx reinsert
+ * @skb: buffer
+ * @dev: tunnel device
+ * @net: netns for packet i/o
+ *
+ * After decapsulation, packet is going to re-enter (netif_rx()) our stack,
+ * so make some cleanups, and perform accounting.
+ * Note: this accounting is not SMP safe.
+ */
+static inline void skb_tunnel_rx(struct sk_buff *skb, struct net_device *dev,
+ struct net *net)
+{
+ /* TODO : stats should be SMP safe */
+ dev->stats.rx_packets++;
+ dev->stats.rx_bytes += skb->len;
+ __skb_tunnel_rx(skb, dev, net);
+}
+
+static inline u32 dst_tclassid(const struct sk_buff *skb)
+{
+#ifdef CONFIG_IP_ROUTE_CLASSID
+ const struct dst_entry *dst;
+
+ dst = skb_dst(skb);
+ if (dst)
+ return dst->tclassid;
+#endif
+ return 0;
+}
+
+int dst_discard_out(struct net *net, struct sock *sk, struct sk_buff *skb);
+static inline int dst_discard(struct sk_buff *skb)
+{
+ return dst_discard_out(&init_net, skb->sk, skb);
+}
+void *dst_alloc(struct dst_ops *ops, struct net_device *dev, int initial_ref,
+ int initial_obsolete, unsigned short flags);
+void dst_init(struct dst_entry *dst, struct dst_ops *ops,
+ struct net_device *dev, int initial_ref, int initial_obsolete,
+ unsigned short flags);
+struct dst_entry *dst_destroy(struct dst_entry *dst);
+void dst_dev_put(struct dst_entry *dst);
+
+static inline void dst_confirm(struct dst_entry *dst)
+{
+}
+
+static inline struct neighbour *dst_neigh_lookup(const struct dst_entry *dst, const void *daddr)
+{
+ struct neighbour *n = dst->ops->neigh_lookup(dst, NULL, daddr);
+ return IS_ERR(n) ? NULL : n;
+}
+
+static inline struct neighbour *dst_neigh_lookup_skb(const struct dst_entry *dst,
+ struct sk_buff *skb)
+{
+ struct neighbour *n = dst->ops->neigh_lookup(dst, skb, NULL);
+ return IS_ERR(n) ? NULL : n;
+}
+
+static inline void dst_confirm_neigh(const struct dst_entry *dst,
+ const void *daddr)
+{
+ if (dst->ops->confirm_neigh)
+ dst->ops->confirm_neigh(dst, daddr);
+}
+
+static inline void dst_link_failure(struct sk_buff *skb)
+{
+ struct dst_entry *dst = skb_dst(skb);
+ if (dst && dst->ops && dst->ops->link_failure)
+ dst->ops->link_failure(skb);
+}
+
+static inline void dst_set_expires(struct dst_entry *dst, int timeout)
+{
+ unsigned long expires = jiffies + timeout;
+
+ if (expires == 0)
+ expires = 1;
+
+ if (dst->expires == 0 || time_before(expires, dst->expires))
+ dst->expires = expires;
+}
+
+/* Output packet to network from transport. */
+static inline int dst_output(struct net *net, struct sock *sk, struct sk_buff *skb)
+{
+ return skb_dst(skb)->output(net, sk, skb);
+}
+
+/* Input packet from network to transport. */
+static inline int dst_input(struct sk_buff *skb)
+{
+ return skb_dst(skb)->input(skb);
+}
+
+static inline struct dst_entry *dst_check(struct dst_entry *dst, u32 cookie)
+{
+ if (dst->obsolete)
+ dst = dst->ops->check(dst, cookie);
+ return dst;
+}
+
+/* Flags for xfrm_lookup flags argument. */
+enum {
+ XFRM_LOOKUP_ICMP = 1 << 0,
+ XFRM_LOOKUP_QUEUE = 1 << 1,
+ XFRM_LOOKUP_KEEP_DST_REF = 1 << 2,
+};
+
+struct flowi;
+#ifndef CONFIG_XFRM
+static inline struct dst_entry *xfrm_lookup(struct net *net,
+ struct dst_entry *dst_orig,
+ const struct flowi *fl,
+ const struct sock *sk,
+ int flags)
+{
+ return dst_orig;
+}
+
+static inline struct dst_entry *
+xfrm_lookup_with_ifid(struct net *net, struct dst_entry *dst_orig,
+ const struct flowi *fl, const struct sock *sk,
+ int flags, u32 if_id)
+{
+ return dst_orig;
+}
+
+static inline struct dst_entry *xfrm_lookup_route(struct net *net,
+ struct dst_entry *dst_orig,
+ const struct flowi *fl,
+ const struct sock *sk,
+ int flags)
+{
+ return dst_orig;
+}
+
+static inline struct xfrm_state *dst_xfrm(const struct dst_entry *dst)
+{
+ return NULL;
+}
+
+#else
+struct dst_entry *xfrm_lookup(struct net *net, struct dst_entry *dst_orig,
+ const struct flowi *fl, const struct sock *sk,
+ int flags);
+
+struct dst_entry *xfrm_lookup_with_ifid(struct net *net,
+ struct dst_entry *dst_orig,
+ const struct flowi *fl,
+ const struct sock *sk, int flags,
+ u32 if_id);
+
+struct dst_entry *xfrm_lookup_route(struct net *net, struct dst_entry *dst_orig,
+ const struct flowi *fl, const struct sock *sk,
+ int flags);
+
+/* skb attached with this dst needs transformation if dst->xfrm is valid */
+static inline struct xfrm_state *dst_xfrm(const struct dst_entry *dst)
+{
+ return dst->xfrm;
+}
+#endif
+
+static inline void skb_dst_update_pmtu(struct sk_buff *skb, u32 mtu)
+{
+ struct dst_entry *dst = skb_dst(skb);
+
+ if (dst && dst->ops->update_pmtu)
+ dst->ops->update_pmtu(dst, NULL, skb, mtu);
+}
+
+static inline void skb_tunnel_check_pmtu(struct sk_buff *skb,
+ struct dst_entry *encap_dst,
+ int headroom)
+{
+ u32 encap_mtu = dst_mtu(encap_dst);
+
+ if (skb->len > encap_mtu - headroom)
+ skb_dst_update_pmtu(skb, encap_mtu - headroom);
+}
+
+#endif /* _NET_DST_H */