Merge tag 'trace-v7.3-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-tracegrafted

Pull tracing fixes from Steven Rostedt:

 - Don't destroy user event fields when removal fails

   User event fields are destroyed before the event is removed from
   visibility. But that can fail leaving the still visible event with no
   fields. Move the destroying of the fields to after the event is
   successfully removed from visibility.

 - Initialize function graph state is fork before calling
   copy_exec_state()

   For non-CLONE_VM forks, copy_exec_state() allocates a new
   task_exec_state. If that allocation fails, ftrace_graph_exit_task()
   will free the tasks ret_stack pointer. Since that pointer is still
   using the parent's ret_stack, it mistakenly frees the parent's
   pointer too.

   Call ftrace_graph_init() on the task first which will NULL out the
   new tasks's ret_stack and if the copy fails, it will not free
   anything.

 - Remove FGRAPH_MAX_INDEX

   The macro FGRAPH_MAX_INDEX was added but never used. Remove it.

 - Save ent_size in function graph printing of nested functions

   The function graph tracer needs to look at the next event to see if
   the next event is the return of the current function entry. If it is,
   it prints a single line:

	ktime_get();

   Otherwise it prints it like a nested function:

	tick_nohz_irq_exit() {
	    ktime_get();
	    kcpustat_irq_exit();
	}

   In order to look at the next event, it must save the current event so
   that it has the information to print from it. It saves the event in
   the iterator descriptor called "ent". What it doesn't save is the
   ent_size of the event which is now used to know if the function graph
   arguments are to be printed. The peek doesn't save the size so the
   size used happens to be that of the size of the last event that was
   seen.

   Save the entry event size in the iterator descriptor so that the
   correct size is used.

 - Fix several errors with freeing data in the histogram code

   The histogram code had a lot of leaked or or incorrect accounting
   when failures happen. Correct them.

 - Fix histogram regression of .percent and .graph modifiers

   Up until 6.3 histogram values could have "percent" or "graph"
   modifiers that changed how they were printed. But a change that added
   restricting histograms values from being strings, stack traces and
   other modifiers inadvertently prevented them from using the percent
   and graph modifiers, which were legal use cases for values.

   Put back the percent and graph modifiers.

 - Fix various typos in the comments

 - Set the trace_clock before initializing a histogram with clock
   argument

   The histogram API allows the user to specific which trace clock to
   use via a "clock=" string. The histogram is set up first before the
   clock is checked. If the passed in clock is not valid, it exits
   without fully fixing up the histogram leaving it on the list and a
   use-after-free can trigger.

   Update the clock argument first and if it fails then exit gracefully
   before the histogram trigger is placed on any lists.

 - Restore :mod: trailer after parsing in ftrace_set_clr_event

   The function ftrace_set_clr_event() modifies the parse string and
   needs to put it back to what was passed in. It searches for ":mod:"
   via a strsep() but fails to put back the first ':' in the string.

   Add back the ':' in the passed in string.

 - Take trace_array reference when opening a tracer options file

   The options files are dynamically created and some tracers add their
   own options. When a tracer adds their own list of options, the
   trace_array holding them has an array to hold the list of options for
   each tracer. This array increases in size via a krealloc(), and the
   new entry gets a newly allocated array to hold the options of the new
   tracer being added.

   The element in each entry of the tracer's option array holds a
   pointer back to the trace_array, a pointer to the tracer it is
   associated to, a pointer to the flags of the option.

   The issue is that these arrays are freed when the trace_array is
   freed when its instance it represents is removed from the instances
   directory. There's a race that an open of one of these options files
   can happen when the instance is being removed.

   Add a new helper function to be called by the open function of the
   options file to iterate all existing trace_arrays under a lock and
   find the one that has the given option element in one of it's tracer
   arrays. If found, then update the associated trace_array's reference
   counter to keep it from being freed. If not found, have the open call
   return -ENODEV.

 - Disable interrupts when acquiring the lock in rb_wake_up_waiters()

   The function rb_wake_up_waiters() assumes it will be called in
   interrupt context and does not disable irqs when taking
   cpu_buffer->reader_lock, which can be called in hard interrupt
   context. The issue is in PREEMPT_RT, this function is called in
   thread context leaving this lock open to a deadlock.

   Take the lock with interrupts disabled.

 - Use rcu_assign_pointer() for tmp_ops filter hash

   The tmp_ops used in update_ftrace_direct_mod() assigns its
   filter_hash field directly, but that field is annotated as __rcu and
   sparse complains. Assign it with rcu_assign_pointer()

 - Fix use-after-free in enable_trigger_private_data_free()

   The trace_event_call is accessed through the event_trigger_data's
   trace_event_file pointer to put the trace_event_call on freeing. The
   issue is that the trace_event_file data may have been freed already
   causing a use-after-free. Add a field to the event_trigger_data that
   points directly to the trace_event_call so that it can decrement its
   reference directly without needing to go through the
   trace_event_file.

 - Fix accounting of buffer data remote headers

   trace_buffer_desc_size() and trace_remote_alloc_buffer() undercount
   the number of pages is needed for the asked for size as it doesn't
   take into account the meta data on each page. Add a helper function
   to do the calculation properly and use that in these functions.

 - Catch nr_page_va overflow in ring_buffer_desc sizing

   The number of pages per remote ring buffer is capped by
   ring_buffer_desc::nr_page_va (32 bits). A buffer_size large enough to
   overflow that field would silently allocate a descriptor smaller than
   what was asked for.

 - Do not resize the subbuf order if any per_cpu buffer is disabled

   The mmapping of ring buffers disables resizing the subbuffers, but it
   is done per-cpu whereas the subbuf size change is done for all the
   per_cpu buffers under the buffer->mutex. It could change the size of
   some while the mapping is happening on others. Have the resize of the
   subbuf order check all the per_cpu buffers under the lock to see if
   any of them is disabled before starting and causing an inconsistency
   between buffers that are being mapped.

* tag 'trace-v7.3-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace: (25 commits)
  ring-buffer: Check resize_disabled before publishing the new subbuf order
  tracing/remotes: Catch nr_page_va overflow in ring_buffer_desc sizing
  tracing/remotes: Account for ring buffer page header in size calculation
  tracing: Don't dereference trace_event_file in deferred trigger free
  ftrace: Use rcu_assign_pointer() for tmp_ops filter hash
  ring-buffer: Acquire the lock with irqsave in rb_wake_up_waiters()
  tracing: Take trace_array reference when opening a tracer options file
  tracing: Fix ring_buffer_read_page_size() kernel-doc
  tracing: Restore :mod: trailer after parsing in ftrace_set_clr_event()
  tracing: Fix memory corruption from a "STACKTRACE" histogram key
  tracing: Fix memory corruption from the histogram stacktrace modifier
  tracing: Undo the registration when enabling the histogram trigger fails
  tracing: Take the reference before publishing the named histogram trigger
  tracing: Set the trace clock before registering the histogram trigger
  tracing: Fix typo "preceeded" in comment
  tracing: Fix typo "availabe" in comment
  tracing: Let histogram values keep the percent and graph modifiers
  tracing: Keep the entry count when the histogram stats allocation fails
  tracing: Free histogram the field rejected for a bad modifier
  tracing: Free histogram the var ref when its initialization fails
  ...

1 files changed, 621 insertions, 0 deletions

diff --git a/include/net/dst.h b/include/net/dst.h
new file mode 100644
index 000000000..307073eae
--- /dev/null
+++ b/include/net/dst.h
@@ -0,0 +1,621 @@
+/* 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 <linux/rcuref.h>
+#include <net/neighbour.h>
+#include <asm/processor.h>
+#include <linux/indirect_call_wrapper.h>
+
+struct sk_buff;
+
+struct dst_entry {
+	union {
+		struct net_device       *dev;
+		struct net_device __rcu *dev_rcu;
+	};
+	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_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 */
+
+	/*
+	 * __rcuref wants to be on a different cache line from
+	 * input/output/ops or performance tanks badly
+	 */
+#ifdef CONFIG_64BIT
+	rcuref_t		__rcuref;	/* 64-bit offset 64 */
+#endif
+	int			__use;
+	unsigned long		lastuse;
+	struct rcu_head		rcu_head;
+	short			error;
+	short			__pad;
+	__u32			tclassid;
+#ifndef CONFIG_64BIT
+	struct lwtunnel_state   *lwtstate;
+	rcuref_t		__rcuref;	/* 32-bit offset 64 */
+#endif
+	netdevice_tracker	dev_tracker;
+
+	/*
+	 * Used by rtable and rt6_info. Moves lwtstate into the next cache
+	 * line on 64bit so that lwtstate does not cause false sharing with
+	 * __rcuref under contention of __rcuref. This also puts the
+	 * frequently accessed members of rtable and rt6_info out of the
+	 * __rcuref cache line.
+	 */
+	struct list_head	rt_uncached;
+	struct uncached_list	*rt_uncached_list;
+#ifdef CONFIG_64BIT
+	struct lwtunnel_state   *lwtstate;
+#endif
+};
+
+struct dst_metrics {
+	u32		metrics[RTAX_MAX];
+	refcount_t	refcnt;
+} __aligned(4);		/* Low pointer bits contain DST_METRICS_FLAGS */
+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	(1U << 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;
+}
+
+INDIRECT_CALLABLE_DECLARE(unsigned int ip6_mtu(const struct dst_entry *));
+INDIRECT_CALLABLE_DECLARE(unsigned int ipv4_mtu(const struct dst_entry *));
+static inline u32 dst_mtu(const struct dst_entry *dst)
+{
+	return INDIRECT_CALL_INET(dst->ops->mtu, ip6_mtu, ipv4_mtu, dst);
+}
+
+/* Variant of dst_mtu() for IPv4 users. */
+static inline u32 dst4_mtu(const struct dst_entry *dst)
+{
+	return INDIRECT_CALL_1(dst->ops->mtu, ipv4_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 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 __rcuref in struct dst_entry
+	 */
+	BUILD_BUG_ON(offsetof(struct dst_entry, __rcuref) & 63);
+	WARN_ON(!rcuref_get(&dst->__rcuref));
+}
+
+static inline void dst_use_noref(struct dst_entry *dst, unsigned long time)
+{
+	if (unlikely(time != READ_ONCE(dst->lastuse))) {
+		dst->__use++;
+		WRITE_ONCE(dst->lastuse, 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->slow_gro |= !!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 rcuref_get(&dst->__rcuref);
+}
+
+/**
+ * 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.
+ * Returns: true if dst is refcounted.
+ */
+static inline bool 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->slow_gro |= !!dst;
+	}
+
+	return skb->_skb_refdst != 0UL;
+}
+
+
+/**
+ *	__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 recalculate 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)
+{
+	DEV_STATS_INC(dev, rx_packets);
+	DEV_STATS_ADD(dev, 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_obsolete, unsigned short flags);
+void dst_init(struct dst_entry *dst, struct dst_ops *ops,
+	      struct net_device *dev, int initial_obsolete,
+	      unsigned short flags);
+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;
+
+	if (WARN_ON_ONCE(!dst->ops->neigh_lookup))
+		return NULL;
+
+	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 old, expires = jiffies + timeout;
+
+	if (expires == 0)
+		expires = 1;
+
+	old = READ_ONCE(dst->expires);
+
+	if (!old || time_before(expires, old))
+		WRITE_ONCE(dst->expires, expires);
+}
+
+static inline unsigned int dst_dev_overhead(struct dst_entry *dst,
+					    struct sk_buff *skb)
+{
+	if (likely(dst))
+		return LL_RESERVED_SPACE(dst->dev);
+
+	return skb->mac_len;
+}
+
+INDIRECT_CALLABLE_DECLARE(int ip6_output(struct net *, struct sock *,
+					 struct sk_buff *));
+INDIRECT_CALLABLE_DECLARE(int ip_output(struct net *, struct sock *,
+					 struct sk_buff *));
+/* Output packet to network from transport.  */
+static inline int dst_output(struct net *net, struct sock *sk, struct sk_buff *skb)
+{
+	return INDIRECT_CALL_INET(READ_ONCE(skb_dst(skb)->output),
+				  ip6_output, ip_output,
+				  net, sk, skb);
+}
+
+INDIRECT_CALLABLE_DECLARE(int ip6_input(struct sk_buff *));
+INDIRECT_CALLABLE_DECLARE(int ip_local_deliver(struct sk_buff *));
+/* Input packet from network to transport.  */
+static inline int dst_input(struct sk_buff *skb)
+{
+	return INDIRECT_CALL_INET(READ_ONCE(skb_dst(skb)->input),
+				  ip6_input, ip_local_deliver, skb);
+}
+
+INDIRECT_CALLABLE_DECLARE(struct dst_entry *ip6_dst_check(struct dst_entry *,
+							  u32));
+INDIRECT_CALLABLE_DECLARE(struct dst_entry *ipv4_dst_check(struct dst_entry *,
+							   u32));
+static inline struct dst_entry *dst_check(struct dst_entry *dst, u32 cookie)
+{
+	if (READ_ONCE(dst->obsolete))
+		dst = INDIRECT_CALL_INET(dst->ops->check, ip6_dst_check,
+					 ipv4_dst_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, true);
+}
+
+/* update dst pmtu but not do neighbor confirm */
+static inline void skb_dst_update_pmtu_no_confirm(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, false);
+}
+
+static inline struct net_device *dst_dev(const struct dst_entry *dst)
+{
+	return READ_ONCE(dst->dev);
+}
+
+static inline struct net_device *dst_dev_rcu(const struct dst_entry *dst)
+{
+	return rcu_dereference(dst->dev_rcu);
+}
+
+static inline struct net *dst_dev_net_rcu(const struct dst_entry *dst)
+{
+	return dev_net_rcu(dst_dev_rcu(dst));
+}
+
+static inline struct net_device *skb_dst_dev(const struct sk_buff *skb)
+{
+	return dst_dev(skb_dst(skb));
+}
+
+static inline struct net_device *skb_dst_dev_rcu(const struct sk_buff *skb)
+{
+	return dst_dev_rcu(skb_dst(skb));
+}
+
+static inline struct net *skb_dst_dev_net(const struct sk_buff *skb)
+{
+	return dev_net(skb_dst_dev(skb));
+}
+
+static inline struct net *skb_dst_dev_net_rcu(const struct sk_buff *skb)
+{
+	return dev_net_rcu(skb_dst_dev_rcu(skb));
+}
+
+struct dst_entry *dst_blackhole_check(struct dst_entry *dst, u32 cookie);
+void dst_blackhole_update_pmtu(struct dst_entry *dst, struct sock *sk,
+			       struct sk_buff *skb, u32 mtu, bool confirm_neigh);
+void dst_blackhole_redirect(struct dst_entry *dst, struct sock *sk,
+			    struct sk_buff *skb);
+u32 *dst_blackhole_cow_metrics(struct dst_entry *dst, unsigned long old);
+struct neighbour *dst_blackhole_neigh_lookup(const struct dst_entry *dst,
+					     struct sk_buff *skb,
+					     const void *daddr);
+unsigned int dst_blackhole_mtu(const struct dst_entry *dst);
+
+#endif /* _NET_DST_H */