[deliverable/linux.git] / include / net / dst.h

/*
 * 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;
	unsigned long           expires;
	struct dst_entry	*path;
	struct dst_entry	*from;
#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_NOHASH		0x0008
#define DST_NOCACHE		0x0010
#define DST_NOCOUNT		0x0020
#define DST_FAKE_RTABLE		0x0040
#define DST_XFRM_TUNNEL		0x0080
#define DST_XFRM_QUEUE		0x0100
#define DST_METADATA		0x0200

	unsigned short		pending_confirm;

	short			error;

	/* 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 */
#ifdef CONFIG_IP_ROUTE_CLASSID
	__u32			tclassid;
#else
	__u32			__pad2;
#endif

#ifdef CONFIG_64BIT
	/*
	 * Align __refcnt to a 64 bytes alignment
	 * (L1_CACHE_SIZE would be too much)
	 */
	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;
	struct lwtunnel_state   *lwtstate;
	union {
		struct dst_entry	*next;
		struct rtable __rcu	*rt_next;
		struct rt6_info		*rt6_next;
		struct dn_route __rcu	*dn_next;
	};
};

u32 *dst_cow_metrics_generic(struct dst_entry *dst, unsigned long old);
extern const u32 dst_default_metrics[];

#define DST_METRICS_READ_ONLY		0x1UL
#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
	 * __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 inline struct dst_entry *dst_clone(struct dst_entry *dst)
{
	if (dst)
		atomic_inc(&dst->__refcnt);
	return dst;
}

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, 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);
}

/**
 * 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));
	}
}

/**
 * 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)
{
	if (dst->flags & DST_NOCACHE)
		return atomic_inc_not_zero(&dst->__refcnt);
	dst_hold(dst);
	return true;
}

/**
 * skb_dst_force_safe - 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_safe(struct sk_buff *skb)
{
	if (skb_dst_is_noref(skb)) {
		struct dst_entry *dst = skb_dst(skb);

		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
 *
 *	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);
void __dst_free(struct dst_entry *dst);
struct dst_entry *dst_destroy(struct dst_entry *dst);

static inline void dst_free(struct dst_entry *dst)
{
	if (dst->obsolete > 0)
		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)
{
	dst->pending_confirm = 1;
}

static inline int dst_neigh_output(struct dst_entry *dst, struct neighbour *n,
				   struct sk_buff *skb)
{
	const struct hh_cache *hh;

	if (dst->pending_confirm) {
		unsigned long now = jiffies;

		dst->pending_confirm = 0;
		/* avoid dirtying neighbour */
		if (n->confirmed != now)
			n->confirmed = now;
	}

	hh = &n->hh;
	if ((n->nud_state & NUD_CONNECTED) && hh->hh_len)
		return neigh_hh_output(hh, skb);
	else
		return n->output(n, skb);
}

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_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;
}

void dst_subsys_init(void);

/* 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_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_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

#endif /* _NET_DST_H */
Commit	Line	Data
	1	/*
	2	* net/dst.h Protocol independent destination cache definitions.
	3	*
	4	* Authors: Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
	5	*
	6	*/
	7
	8	#ifndef _NET_DST_H
	9	#define _NET_DST_H
	10
	11	#include <net/dst_ops.h>
	12	#include <linux/netdevice.h>
	13	#include <linux/rtnetlink.h>
	14	#include <linux/rcupdate.h>
	15	#include <linux/bug.h>
	16	#include <linux/jiffies.h>
	17	#include <net/neighbour.h>
	18	#include <asm/processor.h>
	19
	20	#define DST_GC_MIN (HZ/10)
	21	#define DST_GC_INC (HZ/2)
	22	#define DST_GC_MAX (120*HZ)
	23
	24	/* Each dst_entry has reference count and sits in some parent list(s).
	25	* When it is removed from parent list, it is "freed" (dst_free).
	26	* After this it enters dead state (dst->obsolete > 0) and if its refcnt
	27	* is zero, it can be destroyed immediately, otherwise it is added
	28	* to gc list and garbage collector periodically checks the refcnt.
	29	*/
	30
	31	struct sk_buff;
	32
	33	struct dst_entry {
	34	struct rcu_head rcu_head;
	35	struct dst_entry *child;
	36	struct net_device *dev;
	37	struct dst_ops *ops;
	38	unsigned long _metrics;
	39	unsigned long expires;
	40	struct dst_entry *path;
	41	struct dst_entry *from;
	42	#ifdef CONFIG_XFRM
	43	struct xfrm_state *xfrm;
	44	#else
	45	void *__pad1;
	46	#endif
	47	int (input)(struct sk_buff );
	48	int (output)(struct net net, struct sock sk, struct sk_buff skb);
	49
	50	unsigned short flags;
	51	#define DST_HOST 0x0001
	52	#define DST_NOXFRM 0x0002
	53	#define DST_NOPOLICY 0x0004
	54	#define DST_NOHASH 0x0008
	55	#define DST_NOCACHE 0x0010
	56	#define DST_NOCOUNT 0x0020
	57	#define DST_FAKE_RTABLE 0x0040
	58	#define DST_XFRM_TUNNEL 0x0080
	59	#define DST_XFRM_QUEUE 0x0100
	60	#define DST_METADATA 0x0200
	61
	62	unsigned short pending_confirm;
	63
	64	short error;
	65
	66	/* A non-zero value of dst->obsolete forces by-hand validation
	67	* of the route entry. Positive values are set by the generic
	68	* dst layer to indicate that the entry has been forcefully
	69	* destroyed.
	70	*
	71	* Negative values are used by the implementation layer code to
	72	* force invocation of the dst_ops->check() method.
	73	*/
	74	short obsolete;
	75	#define DST_OBSOLETE_NONE 0
	76	#define DST_OBSOLETE_DEAD 2
	77	#define DST_OBSOLETE_FORCE_CHK -1
	78	#define DST_OBSOLETE_KILL -2
	79	unsigned short header_len; /* more space at head required */
	80	unsigned short trailer_len; /* space to reserve at tail */
	81	#ifdef CONFIG_IP_ROUTE_CLASSID
	82	__u32 tclassid;
	83	#else
	84	__u32 __pad2;
	85	#endif
	86
	87	#ifdef CONFIG_64BIT
	88	/*
	89	* Align __refcnt to a 64 bytes alignment
	90	* (L1_CACHE_SIZE would be too much)
	91	*/
	92	long __pad_to_align_refcnt[2];
	93	#endif
	94	/*
	95	* __refcnt wants to be on a different cache line from
	96	* input/output/ops or performance tanks badly
	97	*/
	98	atomic_t __refcnt; /* client references */
	99	int __use;
	100	unsigned long lastuse;
	101	struct lwtunnel_state *lwtstate;
	102	union {
	103	struct dst_entry *next;
	104	struct rtable __rcu *rt_next;
	105	struct rt6_info *rt6_next;
	106	struct dn_route __rcu *dn_next;
	107	};
	108	};
	109
	110	u32 dst_cow_metrics_generic(struct dst_entry dst, unsigned long old);
	111	extern const u32 dst_default_metrics[];
	112
	113	#define DST_METRICS_READ_ONLY 0x1UL
	114	#define DST_METRICS_FLAGS 0x3UL
	115	#define __DST_METRICS_PTR(Y) \
	116	((u32 *)((Y) & ~DST_METRICS_FLAGS))
	117	#define DST_METRICS_PTR(X) __DST_METRICS_PTR((X)->_metrics)
	118
	119	static inline bool dst_metrics_read_only(const struct dst_entry *dst)
	120	{
	121	return dst->_metrics & DST_METRICS_READ_ONLY;
	122	}
	123
	124	void __dst_destroy_metrics_generic(struct dst_entry *dst, unsigned long old);
	125
	126	static inline void dst_destroy_metrics_generic(struct dst_entry *dst)
	127	{
	128	unsigned long val = dst->_metrics;
	129	if (!(val & DST_METRICS_READ_ONLY))
	130	__dst_destroy_metrics_generic(dst, val);
	131	}
	132
	133	static inline u32 dst_metrics_write_ptr(struct dst_entry dst)
	134	{
	135	unsigned long p = dst->_metrics;
	136
	137	BUG_ON(!p);
	138
	139	if (p & DST_METRICS_READ_ONLY)
	140	return dst->ops->cow_metrics(dst, p);
	141	return __DST_METRICS_PTR(p);
	142	}
	143
	144	/* This may only be invoked before the entry has reached global
	145	* visibility.
	146	*/
	147	static inline void dst_init_metrics(struct dst_entry *dst,
	148	const u32 *src_metrics,
	149	bool read_only)
	150	{
	151	dst->_metrics = ((unsigned long) src_metrics) \|
	152	(read_only ? DST_METRICS_READ_ONLY : 0);
	153	}
	154
	155	static inline void dst_copy_metrics(struct dst_entry dest, const struct dst_entry src)
	156	{
	157	u32 *dst_metrics = dst_metrics_write_ptr(dest);
	158
	159	if (dst_metrics) {
	160	u32 *src_metrics = DST_METRICS_PTR(src);
	161
	162	memcpy(dst_metrics, src_metrics, RTAX_MAX * sizeof(u32));
	163	}
	164	}
	165
	166	static inline u32 dst_metrics_ptr(struct dst_entry dst)
	167	{
	168	return DST_METRICS_PTR(dst);
	169	}
	170
	171	static inline u32
	172	dst_metric_raw(const struct dst_entry *dst, const int metric)
	173	{
	174	u32 *p = DST_METRICS_PTR(dst);
	175
	176	return p[metric-1];
	177	}
	178
	179	static inline u32
	180	dst_metric(const struct dst_entry *dst, const int metric)
	181	{
	182	WARN_ON_ONCE(metric == RTAX_HOPLIMIT \|\|
	183	metric == RTAX_ADVMSS \|\|
	184	metric == RTAX_MTU);
	185	return dst_metric_raw(dst, metric);
	186	}
	187
	188	static inline u32
	189	dst_metric_advmss(const struct dst_entry *dst)
	190	{
	191	u32 advmss = dst_metric_raw(dst, RTAX_ADVMSS);
	192
	193	if (!advmss)
	194	advmss = dst->ops->default_advmss(dst);
	195
	196	return advmss;
	197	}
	198
	199	static inline void dst_metric_set(struct dst_entry *dst, int metric, u32 val)
	200	{
	201	u32 *p = dst_metrics_write_ptr(dst);
	202
	203	if (p)
	204	p[metric-1] = val;
	205	}
	206
	207	/* Kernel-internal feature bits that are unallocated in user space. */
	208	#define DST_FEATURE_ECN_CA (1 << 31)
	209
	210	#define DST_FEATURE_MASK (DST_FEATURE_ECN_CA)
	211	#define DST_FEATURE_ECN_MASK (DST_FEATURE_ECN_CA \| RTAX_FEATURE_ECN)
	212
	213	static inline u32
	214	dst_feature(const struct dst_entry *dst, u32 feature)
	215	{
	216	return dst_metric(dst, RTAX_FEATURES) & feature;
	217	}
	218
	219	static inline u32 dst_mtu(const struct dst_entry *dst)
	220	{
	221	return dst->ops->mtu(dst);
	222	}
	223
	224	/* RTT metrics are stored in milliseconds for user ABI, but used as jiffies */
	225	static inline unsigned long dst_metric_rtt(const struct dst_entry *dst, int metric)
	226	{
	227	return msecs_to_jiffies(dst_metric(dst, metric));
	228	}
	229
	230	static inline u32
	231	dst_allfrag(const struct dst_entry *dst)
	232	{
	233	int ret = dst_feature(dst, RTAX_FEATURE_ALLFRAG);
	234	return ret;
	235	}
	236
	237	static inline int
	238	dst_metric_locked(const struct dst_entry *dst, int metric)
	239	{
	240	return dst_metric(dst, RTAX_LOCK) & (1<<metric);
	241	}
	242
	243	static inline void dst_hold(struct dst_entry *dst)
	244	{
	245	/*
	246	* If your kernel compilation stops here, please check
	247	* __pad_to_align_refcnt declaration in struct dst_entry
	248	*/
	249	BUILD_BUG_ON(offsetof(struct dst_entry, __refcnt) & 63);
	250	atomic_inc(&dst->__refcnt);
	251	}
	252
	253	static inline void dst_use(struct dst_entry *dst, unsigned long time)
	254	{
	255	dst_hold(dst);
	256	dst->__use++;
	257	dst->lastuse = time;
	258	}
	259
	260	static inline void dst_use_noref(struct dst_entry *dst, unsigned long time)
	261	{
	262	dst->__use++;
	263	dst->lastuse = time;
	264	}
	265
	266	static inline struct dst_entry dst_clone(struct dst_entry dst)
	267	{
	268	if (dst)
	269	atomic_inc(&dst->__refcnt);
	270	return dst;
	271	}
	272
	273	void dst_release(struct dst_entry *dst);
	274
	275	static inline void refdst_drop(unsigned long refdst)
	276	{
	277	if (!(refdst & SKB_DST_NOREF))
	278	dst_release((struct dst_entry *)(refdst & SKB_DST_PTRMASK));
	279	}
	280
	281	/**
	282	* skb_dst_drop - drops skb dst
	283	* @skb: buffer
	284	*
	285	* Drops dst reference count if a reference was taken.
	286	*/
	287	static inline void skb_dst_drop(struct sk_buff *skb)
	288	{
	289	if (skb->_skb_refdst) {
	290	refdst_drop(skb->_skb_refdst);
	291	skb->_skb_refdst = 0UL;
	292	}
	293	}
	294
	295	static inline void __skb_dst_copy(struct sk_buff *nskb, unsigned long refdst)
	296	{
	297	nskb->_skb_refdst = refdst;
	298	if (!(nskb->_skb_refdst & SKB_DST_NOREF))
	299	dst_clone(skb_dst(nskb));
	300	}
	301
	302	static inline void skb_dst_copy(struct sk_buff nskb, const struct sk_buff oskb)
	303	{
	304	__skb_dst_copy(nskb, oskb->_skb_refdst);
	305	}
	306
	307	/**
	308	* skb_dst_force - makes sure skb dst is refcounted
	309	* @skb: buffer
	310	*
	311	* If dst is not yet refcounted, let's do it
	312	*/
	313	static inline void skb_dst_force(struct sk_buff *skb)
	314	{
	315	if (skb_dst_is_noref(skb)) {
	316	WARN_ON(!rcu_read_lock_held());
	317	skb->_skb_refdst &= ~SKB_DST_NOREF;
	318	dst_clone(skb_dst(skb));
	319	}
	320	}
	321
	322	/**
	323	* dst_hold_safe - Take a reference on a dst if possible
	324	* @dst: pointer to dst entry
	325	*
	326	* This helper returns false if it could not safely
	327	* take a reference on a dst.
	328	*/
	329	static inline bool dst_hold_safe(struct dst_entry *dst)
	330	{
	331	if (dst->flags & DST_NOCACHE)
	332	return atomic_inc_not_zero(&dst->__refcnt);
	333	dst_hold(dst);
	334	return true;
	335	}
	336
	337	/**
	338	* skb_dst_force_safe - makes sure skb dst is refcounted
	339	* @skb: buffer
	340	*
	341	* If dst is not yet refcounted and not destroyed, grab a ref on it.
	342	*/
	343	static inline void skb_dst_force_safe(struct sk_buff *skb)
	344	{
	345	if (skb_dst_is_noref(skb)) {
	346	struct dst_entry *dst = skb_dst(skb);
	347
	348	if (!dst_hold_safe(dst))
	349	dst = NULL;
	350
	351	skb->_skb_refdst = (unsigned long)dst;
	352	}
	353	}
	354
	355
	356	/**
	357	* __skb_tunnel_rx - prepare skb for rx reinsert
	358	* @skb: buffer
	359	* @dev: tunnel device
	360	* @net: netns for packet i/o
	361	*
	362	* After decapsulation, packet is going to re-enter (netif_rx()) our stack,
	363	* so make some cleanups. (no accounting done)
	364	*/
	365	static inline void __skb_tunnel_rx(struct sk_buff skb, struct net_device dev,
	366	struct net *net)
	367	{
	368	skb->dev = dev;
	369
	370	/*
	371	* Clear hash so that we can recalulate the hash for the
	372	* encapsulated packet, unless we have already determine the hash
	373	* over the L4 4-tuple.
	374	*/
	375	skb_clear_hash_if_not_l4(skb);
	376	skb_set_queue_mapping(skb, 0);
	377	skb_scrub_packet(skb, !net_eq(net, dev_net(dev)));
	378	}
	379
	380	/**
	381	* skb_tunnel_rx - prepare skb for rx reinsert
	382	* @skb: buffer
	383	* @dev: tunnel device
	384	*
	385	* After decapsulation, packet is going to re-enter (netif_rx()) our stack,
	386	* so make some cleanups, and perform accounting.
	387	* Note: this accounting is not SMP safe.
	388	*/
	389	static inline void skb_tunnel_rx(struct sk_buff skb, struct net_device dev,
	390	struct net *net)
	391	{
	392	/* TODO : stats should be SMP safe */
	393	dev->stats.rx_packets++;
	394	dev->stats.rx_bytes += skb->len;
	395	__skb_tunnel_rx(skb, dev, net);
	396	}
	397
	398	static inline u32 dst_tclassid(const struct sk_buff *skb)
	399	{
	400	#ifdef CONFIG_IP_ROUTE_CLASSID
	401	const struct dst_entry *dst;
	402
	403	dst = skb_dst(skb);
	404	if (dst)
	405	return dst->tclassid;
	406	#endif
	407	return 0;
	408	}
	409
	410	int dst_discard_out(struct net net, struct sock sk, struct sk_buff *skb);
	411	static inline int dst_discard(struct sk_buff *skb)
	412	{
	413	return dst_discard_out(&init_net, skb->sk, skb);
	414	}
	415	void dst_alloc(struct dst_ops ops, struct net_device *dev, int initial_ref,
	416	int initial_obsolete, unsigned short flags);
	417	void dst_init(struct dst_entry dst, struct dst_ops ops,
	418	struct net_device *dev, int initial_ref, int initial_obsolete,
	419	unsigned short flags);
	420	void __dst_free(struct dst_entry *dst);
	421	struct dst_entry dst_destroy(struct dst_entry dst);
	422
	423	static inline void dst_free(struct dst_entry *dst)
	424	{
	425	if (dst->obsolete > 0)
	426	return;
	427	if (!atomic_read(&dst->__refcnt)) {
	428	dst = dst_destroy(dst);
	429	if (!dst)
	430	return;
	431	}
	432	__dst_free(dst);
	433	}
	434
	435	static inline void dst_rcu_free(struct rcu_head *head)
	436	{
	437	struct dst_entry *dst = container_of(head, struct dst_entry, rcu_head);
	438	dst_free(dst);
	439	}
	440
	441	static inline void dst_confirm(struct dst_entry *dst)
	442	{
	443	dst->pending_confirm = 1;
	444	}
	445
	446	static inline int dst_neigh_output(struct dst_entry dst, struct neighbour n,
	447	struct sk_buff *skb)
	448	{
	449	const struct hh_cache *hh;
	450
	451	if (dst->pending_confirm) {
	452	unsigned long now = jiffies;
	453
	454	dst->pending_confirm = 0;
	455	/* avoid dirtying neighbour */
	456	if (n->confirmed != now)
	457	n->confirmed = now;
	458	}
	459
	460	hh = &n->hh;
	461	if ((n->nud_state & NUD_CONNECTED) && hh->hh_len)
	462	return neigh_hh_output(hh, skb);
	463	else
	464	return n->output(n, skb);
	465	}
	466
	467	static inline struct neighbour dst_neigh_lookup(const struct dst_entry dst, const void *daddr)
	468	{
	469	struct neighbour *n = dst->ops->neigh_lookup(dst, NULL, daddr);
	470	return IS_ERR(n) ? NULL : n;
	471	}
	472
	473	static inline struct neighbour dst_neigh_lookup_skb(const struct dst_entry dst,
	474	struct sk_buff *skb)
	475	{
	476	struct neighbour *n = dst->ops->neigh_lookup(dst, skb, NULL);
	477	return IS_ERR(n) ? NULL : n;
	478	}
	479
	480	static inline void dst_link_failure(struct sk_buff *skb)
	481	{
	482	struct dst_entry *dst = skb_dst(skb);
	483	if (dst && dst->ops && dst->ops->link_failure)
	484	dst->ops->link_failure(skb);
	485	}
	486
	487	static inline void dst_set_expires(struct dst_entry *dst, int timeout)
	488	{
	489	unsigned long expires = jiffies + timeout;
	490
	491	if (expires == 0)
	492	expires = 1;
	493
	494	if (dst->expires == 0 \|\| time_before(expires, dst->expires))
	495	dst->expires = expires;
	496	}
	497
	498	/* Output packet to network from transport. */
	499	static inline int dst_output(struct net net, struct sock sk, struct sk_buff *skb)
	500	{
	501	return skb_dst(skb)->output(net, sk, skb);
	502	}
	503
	504	/* Input packet from network to transport. */
	505	static inline int dst_input(struct sk_buff *skb)
	506	{
	507	return skb_dst(skb)->input(skb);
	508	}
	509
	510	static inline struct dst_entry dst_check(struct dst_entry dst, u32 cookie)
	511	{
	512	if (dst->obsolete)
	513	dst = dst->ops->check(dst, cookie);
	514	return dst;
	515	}
	516
	517	void dst_subsys_init(void);
	518
	519	/* Flags for xfrm_lookup flags argument. */
	520	enum {
	521	XFRM_LOOKUP_ICMP = 1 << 0,
	522	XFRM_LOOKUP_QUEUE = 1 << 1,
	523	XFRM_LOOKUP_KEEP_DST_REF = 1 << 2,
	524	};
	525
	526	struct flowi;
	527	#ifndef CONFIG_XFRM
	528	static inline struct dst_entry xfrm_lookup(struct net net,
	529	struct dst_entry *dst_orig,
	530	const struct flowi *fl,
	531	const struct sock *sk,
	532	int flags)
	533	{
	534	return dst_orig;
	535	}
	536
	537	static inline struct dst_entry xfrm_lookup_route(struct net net,
	538	struct dst_entry *dst_orig,
	539	const struct flowi *fl,
	540	const struct sock *sk,
	541	int flags)
	542	{
	543	return dst_orig;
	544	}
	545
	546	static inline struct xfrm_state dst_xfrm(const struct dst_entry dst)
	547	{
	548	return NULL;
	549	}
	550
	551	#else
	552	struct dst_entry xfrm_lookup(struct net net, struct dst_entry *dst_orig,
	553	const struct flowi fl, const struct sock sk,
	554	int flags);
	555
	556	struct dst_entry xfrm_lookup_route(struct net net, struct dst_entry *dst_orig,
	557	const struct flowi fl, const struct sock sk,
	558	int flags);
	559
	560	/* skb attached with this dst needs transformation if dst->xfrm is valid */
	561	static inline struct xfrm_state dst_xfrm(const struct dst_entry dst)
	562	{
	563	return dst->xfrm;
	564	}
	565	#endif
	566
	567	#endif /* _NET_DST_H */