/* * 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 <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 rcu_head		rcu_head;	struct dst_entry	*child;	struct net_device       *dev;	struct  dst_ops	        *ops;	unsigned long		_metrics;	union {		unsigned long           expires;		/* point to where the dst_entry copied from */		struct dst_entry        *from;	};	struct dst_entry	*path;	struct neighbour __rcu	*_neighbour;#ifdef CONFIG_XFRM	struct xfrm_state	*xfrm;#else	void			*__pad1;#endif	int			(*input)(struct sk_buff*);	int			(*output)(struct sk_buff*); 	int			flags;#define DST_HOST		0x0001#define DST_NOXFRM		0x0002#define DST_NOPOLICY		0x0004#define DST_NOHASH		0x0008#define DST_NOCACHE		0x0010#define DST_NOCOUNT		0x0020#define DST_NOPEER		0x0040#define DST_FAKE_RTABLE		0x0080#define DST_XFRM_TUNNEL		0x0100 	short			error;	short			obsolete;	unsigned short		header_len;	/* more space at head required */	unsigned short		trailer_len;	/* space to reserve at tail */#ifdef CONFIG_IP_ROUTE_CLASSID	__u32			tclassid;#else	__u32			__pad2;#endif 	/*	 * Align __refcnt to a 64 bytes alignment	 * (L1_CACHE_SIZE would be too much)	 */#ifdef CONFIG_64BIT	long			__pad_to_align_refcnt[2];#endif	/*	 * __refcnt wants to be on a different cache line from	 * input/output/ops or performance tanks badly	 */	atomic_t		__refcnt;	/* client references	*/	int			__use;	unsigned long		lastuse;	union {		struct dst_entry	*next;		struct rtable __rcu	*rt_next;		struct rt6_info		*rt6_next;		struct dn_route __rcu	*dn_next;	};}; static inline struct neighbour *dst_get_neighbour_noref(struct dst_entry *dst){	return rcu_dereference(dst->_neighbour);} static inline struct neighbour *dst_get_neighbour_noref_raw(struct dst_entry *dst){	return rcu_dereference_raw(dst->_neighbour);} static inline void dst_set_neighbour(struct dst_entry *dst, struct neighbour *neigh){	rcu_assign_pointer(dst->_neighbour, neigh);} extern u32 *dst_cow_metrics_generic(struct dst_entry *dst, unsigned long old);extern const u32 dst_default_metrics[RTAX_MAX]; #define DST_METRICS_READ_ONLY	0x1UL#define __DST_METRICS_PTR(Y)	\	((u32 *)((Y) & ~DST_METRICS_READ_ONLY))#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;} extern 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;} static inline u32dst_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 void set_dst_metric_rtt(struct dst_entry *dst, int metric,				      unsigned long rtt){	dst_metric_set(dst, metric, jiffies_to_msecs(rtt));} static inline u32dst_allfrag(const struct dst_entry *dst){	int ret = dst_feature(dst,  RTAX_FEATURE_ALLFRAG);	return ret;} 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	 * __pad_to_align_refcnt declaration in struct dst_entry	 */	BUILD_BUG_ON(offsetof(struct dst_entry, __refcnt) & 63);	atomic_inc(&dst->__refcnt);} static inline void dst_use(struct dst_entry *dst, unsigned long time){	dst_hold(dst);	dst->__use++;	dst->lastuse = time;} static inline void dst_use_noref(struct dst_entry *dst, unsigned long time){	dst->__use++;	dst->lastuse = time;} static inlinestruct dst_entry * dst_clone(struct dst_entry * dst){	if (dst)		atomic_inc(&dst->__refcnt);	return dst;} extern void dst_release(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, const struct sk_buff *oskb){	nskb->_skb_refdst = oskb->_skb_refdst;	if (!(nskb->_skb_refdst & SKB_DST_NOREF))		dst_clone(skb_dst(nskb));} /** * skb_dst_force - makes sure skb dst is refcounted * @skb: buffer * * If dst is not yet refcounted, let's do it */static inline void skb_dst_force(struct sk_buff *skb){	if (skb_dst_is_noref(skb)) {		WARN_ON(!rcu_read_lock_held());		skb->_skb_refdst &= ~SKB_DST_NOREF;		dst_clone(skb_dst(skb));	}}  /** *	__skb_tunnel_rx - prepare skb for rx reinsert *	@skb: buffer *	@dev: tunnel device * *	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){	skb->dev = dev; 	/*	 * Clear rxhash so that we can recalulate the hash for the	 * encapsulated packet, unless we have already determine the hash	 * over the L4 4-tuple.	 */	if (!skb->l4_rxhash)		skb->rxhash = 0;	skb_set_queue_mapping(skb, 0);	skb_dst_drop(skb);	nf_reset(skb);} /** *	skb_tunnel_rx - prepare skb for rx reinsert *	@skb: buffer *	@dev: tunnel device * *	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){	/* TODO : stats should be SMP safe */	dev->stats.rx_packets++;	dev->stats.rx_bytes += skb->len;	__skb_tunnel_rx(skb, dev);} /* Children define the path of the packet through the * Linux networking.  Thus, destinations are stackable. */ static inline struct dst_entry *skb_dst_pop(struct sk_buff *skb){	struct dst_entry *child = dst_clone(skb_dst(skb)->child); 	skb_dst_drop(skb);	return child;} extern int dst_discard(struct sk_buff *skb);extern void *dst_alloc(struct dst_ops * ops, struct net_device *dev,		       int initial_ref, int initial_obsolete, int flags);extern void __dst_free(struct dst_entry * dst);extern struct dst_entry *dst_destroy(struct dst_entry * dst); static inline void dst_free(struct dst_entry * dst){	if (dst->obsolete > 1)		return;	if (!atomic_read(&dst->__refcnt)) {		dst = dst_destroy(dst);		if (!dst)			return;	}	__dst_free(dst);} static inline void dst_rcu_free(struct rcu_head *head){	struct dst_entry *dst = container_of(head, struct dst_entry, rcu_head);	dst_free(dst);} static inline void dst_confirm(struct dst_entry *dst){	if (dst) {		struct neighbour *n; 		rcu_read_lock();		n = dst_get_neighbour_noref(dst);		neigh_confirm(n);		rcu_read_unlock();	}} static inline struct neighbour *dst_neigh_lookup(const struct dst_entry *dst, const void *daddr){	return dst->ops->neigh_lookup(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 sk_buff *skb){	return skb_dst(skb)->output(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;} extern void		dst_init(void); /* Flags for xfrm_lookup flags argument. */enum {	XFRM_LOOKUP_ICMP = 1 << 0,}; struct flowi;#ifndef CONFIG_XFRMstatic inline struct dst_entry *xfrm_lookup(struct net *net,					    struct dst_entry *dst_orig,					    const struct flowi *fl, struct sock *sk,					    int flags){	return dst_orig;} #elseextern struct dst_entry *xfrm_lookup(struct net *net, struct dst_entry *dst_orig,				     const struct flowi *fl, struct sock *sk,				     int flags);#endif #endif /* _NET_DST_H */