/* 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 u32dst_metric_raw(const struct dst_entry *dst, const int metric){	u32 *p = DST_METRICS_PTR(dst); 	return p[metric-1];} static inline u32dst_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 u32dst_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 u32dst_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 intdst_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,

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