[linux-block.git] / include / net / dst.h

/* 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 rcu_head		rcu_head;
	struct dst_entry	*child;
	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_NOCOUNT		0x0008
#define DST_FAKE_RTABLE		0x0010
#define DST_XFRM_TUNNEL		0x0020
#define DST_XFRM_QUEUE		0x0040
#define DST_METADATA		0x0080

	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 */
	unsigned short		__pad3;

#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;
	};
};

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
	 * __pad_to_align_refcnt declaration 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(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)
		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
 *
 *	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_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
b2441318	1	/* SPDX-License-Identifier: GPL-2.0 */
1da177e4 LT	2	/*
	3	* net/dst.h Protocol independent destination cache definitions.
	4	*
	5	* Authors: Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
	6	*
	7	*/
	8
	9	#ifndef _NET_DST_H
	10	#define _NET_DST_H
	11
86393e52	12	#include <net/dst_ops.h>
14c85021	13	#include <linux/netdevice.h>
1da177e4 LT	14	#include <linux/rtnetlink.h>
1da177e4 LT	15	#include <linux/rcupdate.h>
187f1882	16	#include <linux/bug.h>
1da177e4	17	#include <linux/jiffies.h>
9620fef2	18	#include <linux/refcount.h>
1da177e4 LT	19	#include <net/neighbour.h>
	20	#include <asm/processor.h>
	21
1da177e4 LT	22	#define DST_GC_MIN (HZ/10)
	23	#define DST_GC_INC (HZ/2)
	24	#define DST_GC_MAX (120*HZ)
	25
	26	/* Each dst_entry has reference count and sits in some parent list(s).
	27	* When it is removed from parent list, it is "freed" (dst_free).
	28	* After this it enters dead state (dst->obsolete > 0) and if its refcnt
	29	* is zero, it can be destroyed immediately, otherwise it is added
	30	* to gc list and garbage collector periodically checks the refcnt.
	31	*/
	32
	33	struct sk_buff;
	34
fd2c3ef7	35	struct dst_entry {
66727145	36	struct net_device *dev;
1e19e02c	37	struct rcu_head rcu_head;
1da177e4	38	struct dst_entry *child;
62fa8a84 DM	39	struct dst_ops *ops;
62fa8a84 DM	40	unsigned long _metrics;
ecd98837	41	unsigned long expires;
f1dd9c37	42	struct dst_entry *path;
ecd98837	43	struct dst_entry *from;
def8b4fa	44	#ifdef CONFIG_XFRM
1da177e4	45	struct xfrm_state *xfrm;
5635c10d ED	46	#else
5635c10d ED	47	void *__pad1;
def8b4fa	48	#endif
7f95e188	49	int (input)(struct sk_buff );
ede2059d	50	int (output)(struct net net, struct sock sk, struct sk_buff skb);
1da177e4	51
5110effe	52	unsigned short flags;
f6b72b62 DM	53	#define DST_HOST 0x0001
	54	#define DST_NOXFRM 0x0002
	55	#define DST_NOPOLICY 0x0004
1eb04e7c WW	56	#define DST_NOCOUNT 0x0008
	57	#define DST_FAKE_RTABLE 0x0010
	58	#define DST_XFRM_TUNNEL 0x0020
	59	#define DST_XFRM_QUEUE 0x0040
	60	#define DST_METADATA 0x0080
f6b72b62	61
62fa8a84	62	short error;
f5b0a874 DM	63
	64	/* A non-zero value of dst->obsolete forces by-hand validation
	65	* of the route entry. Positive values are set by the generic
	66	* dst layer to indicate that the entry has been forcefully
	67	* destroyed.
	68	*
	69	* Negative values are used by the implementation layer code to
	70	* force invocation of the dst_ops->check() method.
	71	*/
62fa8a84	72	short obsolete;
f5b0a874 DM	73	#define DST_OBSOLETE_NONE 0
	74	#define DST_OBSOLETE_DEAD 2
	75	#define DST_OBSOLETE_FORCE_CHK -1
ceb33206	76	#define DST_OBSOLETE_KILL -2
62fa8a84 DM	77	unsigned short header_len; /* more space at head required */
62fa8a84 DM	78	unsigned short trailer_len; /* space to reserve at tail */
51ce8bd4 JA	79	unsigned short __pad3;
51ce8bd4 JA	80
c7066f70	81	#ifdef CONFIG_IP_ROUTE_CLASSID
f1dd9c37	82	__u32 tclassid;
5635c10d ED	83	#else
5635c10d ED	84	__u32 __pad2;
f1dd9c37 ZY	85	#endif
f1dd9c37 ZY	86
751a587a	87	#ifdef CONFIG_64BIT
5635c10d ED	88	/*
	89	* Align __refcnt to a 64 bytes alignment
	90	* (L1_CACHE_SIZE would be too much)
	91	*/
0868e253	92	long __pad_to_align_refcnt[2];
5635c10d	93	#endif
f1dd9c37 ZY	94	/*
	95	* __refcnt wants to be on a different cache line from
	96	* input/output/ops or performance tanks badly
	97	*/
1e19e02c ED	98	atomic_t __refcnt; /* client references */
1e19e02c ED	99	int __use;
f1dd9c37	100	unsigned long lastuse;
751a587a	101	struct lwtunnel_state *lwtstate;
1e19e02c	102	union {
fc766e4c ED	103	struct dst_entry *next;
	104	struct rtable __rcu *rt_next;
	105	struct rt6_info *rt6_next;
	106	struct dn_route __rcu *dn_next;
1e19e02c	107	};
1da177e4 LT	108	};
1da177e4 LT	109
3fb07daf ED	110	struct dst_metrics {
3fb07daf ED	111	u32 metrics[RTAX_MAX];
9620fef2	112	refcount_t refcnt;
3fb07daf ED	113	};
	114	extern const struct dst_metrics dst_default_metrics;
	115
a4023dd0	116	u32 dst_cow_metrics_generic(struct dst_entry dst, unsigned long old);
62fa8a84	117
e5fd387a	118	#define DST_METRICS_READ_ONLY 0x1UL
3fb07daf	119	#define DST_METRICS_REFCOUNTED 0x2UL
e5fd387a	120	#define DST_METRICS_FLAGS 0x3UL
62fa8a84	121	#define __DST_METRICS_PTR(Y) \
e5fd387a	122	((u32 *)((Y) & ~DST_METRICS_FLAGS))
62fa8a84 DM	123	#define DST_METRICS_PTR(X) __DST_METRICS_PTR((X)->_metrics)
	124
	125	static inline bool dst_metrics_read_only(const struct dst_entry *dst)
	126	{
	127	return dst->_metrics & DST_METRICS_READ_ONLY;
	128	}
	129
a4023dd0	130	void __dst_destroy_metrics_generic(struct dst_entry *dst, unsigned long old);
62fa8a84 DM	131
	132	static inline void dst_destroy_metrics_generic(struct dst_entry *dst)
	133	{
	134	unsigned long val = dst->_metrics;
	135	if (!(val & DST_METRICS_READ_ONLY))
	136	__dst_destroy_metrics_generic(dst, val);
	137	}
	138
	139	static inline u32 dst_metrics_write_ptr(struct dst_entry dst)
	140	{
	141	unsigned long p = dst->_metrics;
	142
1f37070d SH	143	BUG_ON(!p);
1f37070d SH	144
62fa8a84 DM	145	if (p & DST_METRICS_READ_ONLY)
	146	return dst->ops->cow_metrics(dst, p);
	147	return __DST_METRICS_PTR(p);
	148	}
	149
	150	/* This may only be invoked before the entry has reached global
	151	* visibility.
	152	*/
	153	static inline void dst_init_metrics(struct dst_entry *dst,
	154	const u32 *src_metrics,
	155	bool read_only)
	156	{
	157	dst->_metrics = ((unsigned long) src_metrics) \|
	158	(read_only ? DST_METRICS_READ_ONLY : 0);
	159	}
	160
	161	static inline void dst_copy_metrics(struct dst_entry dest, const struct dst_entry src)
	162	{
	163	u32 *dst_metrics = dst_metrics_write_ptr(dest);
	164
	165	if (dst_metrics) {
	166	u32 *src_metrics = DST_METRICS_PTR(src);
	167
	168	memcpy(dst_metrics, src_metrics, RTAX_MAX * sizeof(u32));
	169	}
	170	}
	171
	172	static inline u32 dst_metrics_ptr(struct dst_entry dst)
	173	{
	174	return DST_METRICS_PTR(dst);
	175	}
	176
1da177e4	177	static inline u32
5170ae82	178	dst_metric_raw(const struct dst_entry *dst, const int metric)
1da177e4	179	{
62fa8a84 DM	180	u32 *p = DST_METRICS_PTR(dst);
	181
	182	return p[metric-1];
defb3519 DM	183	}
defb3519 DM	184
5170ae82 DM	185	static inline u32
	186	dst_metric(const struct dst_entry *dst, const int metric)
	187	{
0dbaee3b	188	WARN_ON_ONCE(metric == RTAX_HOPLIMIT \|\|
d33e4553 DM	189	metric == RTAX_ADVMSS \|\|
d33e4553 DM	190	metric == RTAX_MTU);
5170ae82 DM	191	return dst_metric_raw(dst, metric);
	192	}
	193
0dbaee3b DM	194	static inline u32
	195	dst_metric_advmss(const struct dst_entry *dst)
	196	{
	197	u32 advmss = dst_metric_raw(dst, RTAX_ADVMSS);
	198
	199	if (!advmss)
	200	advmss = dst->ops->default_advmss(dst);
	201
	202	return advmss;
	203	}
	204
defb3519 DM	205	static inline void dst_metric_set(struct dst_entry *dst, int metric, u32 val)
defb3519 DM	206	{
62fa8a84	207	u32 *p = dst_metrics_write_ptr(dst);
defb3519	208
62fa8a84 DM	209	if (p)
62fa8a84 DM	210	p[metric-1] = val;
1da177e4 LT	211	}
1da177e4 LT	212
c3a8d947 DB	213	/* Kernel-internal feature bits that are unallocated in user space. */
	214	#define DST_FEATURE_ECN_CA (1 << 31)
	215
	216	#define DST_FEATURE_MASK (DST_FEATURE_ECN_CA)
	217	#define DST_FEATURE_ECN_MASK (DST_FEATURE_ECN_CA \| RTAX_FEATURE_ECN)
	218
0c3adfb8 GBY	219	static inline u32
	220	dst_feature(const struct dst_entry *dst, u32 feature)
	221	{
bb5b7c11	222	return dst_metric(dst, RTAX_FEATURES) & feature;
0c3adfb8 GBY	223	}
0c3adfb8 GBY	224
1da177e4 LT	225	static inline u32 dst_mtu(const struct dst_entry *dst)
1da177e4 LT	226	{
618f9bc7	227	return dst->ops->mtu(dst);
1da177e4 LT	228	}
1da177e4 LT	229
c1e20f7c SH	230	/* RTT metrics are stored in milliseconds for user ABI, but used as jiffies */
	231	static inline unsigned long dst_metric_rtt(const struct dst_entry *dst, int metric)
	232	{
	233	return msecs_to_jiffies(dst_metric(dst, metric));
	234	}
	235
1da177e4 LT	236	static inline u32
	237	dst_allfrag(const struct dst_entry *dst)
	238	{
0c3adfb8	239	int ret = dst_feature(dst, RTAX_FEATURE_ALLFRAG);
1da177e4 LT	240	return ret;
	241	}
	242
	243	static inline int
d33e4553	244	dst_metric_locked(const struct dst_entry *dst, int metric)
1da177e4 LT	245	{
	246	return dst_metric(dst, RTAX_LOCK) & (1<<metric);
	247	}
	248
7f95e188	249	static inline void dst_hold(struct dst_entry *dst)
1da177e4	250	{
5635c10d ED	251	/*
	252	* If your kernel compilation stops here, please check
	253	* __pad_to_align_refcnt declaration in struct dst_entry
	254	*/
	255	BUILD_BUG_ON(offsetof(struct dst_entry, __refcnt) & 63);
44ebe791	256	WARN_ON(atomic_inc_not_zero(&dst->__refcnt) == 0);
1da177e4 LT	257	}
1da177e4 LT	258
03f49f34 PE	259	static inline void dst_use(struct dst_entry *dst, unsigned long time)
	260	{
	261	dst_hold(dst);
	262	dst->__use++;
	263	dst->lastuse = time;
	264	}
	265
7fee226a ED	266	static inline void dst_use_noref(struct dst_entry *dst, unsigned long time)
	267	{
	268	dst->__use++;
	269	dst->lastuse = time;
	270	}
	271
7f95e188	272	static inline struct dst_entry dst_clone(struct dst_entry dst)
1da177e4 LT	273	{
1da177e4 LT	274	if (dst)
222d7dbd	275	dst_hold(dst);
1da177e4 LT	276	return dst;
	277	}
	278
a4023dd0	279	void dst_release(struct dst_entry *dst);
7fee226a	280
5f56f409 WW	281	void dst_release_immediate(struct dst_entry *dst);
5f56f409 WW	282
7fee226a ED	283	static inline void refdst_drop(unsigned long refdst)
	284	{
	285	if (!(refdst & SKB_DST_NOREF))
	286	dst_release((struct dst_entry *)(refdst & SKB_DST_PTRMASK));
	287	}
	288
	289	/**
	290	* skb_dst_drop - drops skb dst
	291	* @skb: buffer
	292	*
	293	* Drops dst reference count if a reference was taken.
	294	*/
adf30907 ED	295	static inline void skb_dst_drop(struct sk_buff *skb)
adf30907 ED	296	{
7fee226a ED	297	if (skb->_skb_refdst) {
	298	refdst_drop(skb->_skb_refdst);
	299	skb->_skb_refdst = 0UL;
	300	}
	301	}
	302
e79e2595	303	static inline void __skb_dst_copy(struct sk_buff *nskb, unsigned long refdst)
7fee226a	304	{
e79e2595	305	nskb->_skb_refdst = refdst;
7fee226a ED	306	if (!(nskb->_skb_refdst & SKB_DST_NOREF))
	307	dst_clone(skb_dst(nskb));
	308	}
	309
e79e2595 JS	310	static inline void skb_dst_copy(struct sk_buff nskb, const struct sk_buff oskb)
	311	{
	312	__skb_dst_copy(nskb, oskb->_skb_refdst);
	313	}
	314
5037e9ef ED	315	/**
	316	* dst_hold_safe - Take a reference on a dst if possible
	317	* @dst: pointer to dst entry
	318	*
	319	* This helper returns false if it could not safely
	320	* take a reference on a dst.
	321	*/
	322	static inline bool dst_hold_safe(struct dst_entry *dst)
	323	{
b2a9c0ed	324	return atomic_inc_not_zero(&dst->__refcnt);
5037e9ef ED	325	}
	326
	327	/**
222d7dbd	328	* skb_dst_force - makes sure skb dst is refcounted
5037e9ef ED	329	* @skb: buffer
	330	*
	331	* If dst is not yet refcounted and not destroyed, grab a ref on it.
	332	*/
222d7dbd	333	static inline void skb_dst_force(struct sk_buff *skb)
5037e9ef ED	334	{
	335	if (skb_dst_is_noref(skb)) {
	336	struct dst_entry *dst = skb_dst(skb);
	337
222d7dbd	338	WARN_ON(!rcu_read_lock_held());
5037e9ef ED	339	if (!dst_hold_safe(dst))
	340	dst = NULL;
	341
	342	skb->_skb_refdst = (unsigned long)dst;
	343	}
	344	}
	345
d19d56dd	346
290b895e ED	347	/**
	348	* __skb_tunnel_rx - prepare skb for rx reinsert
	349	* @skb: buffer
	350	* @dev: tunnel device
ea23192e	351	* @net: netns for packet i/o
290b895e ED	352	*
	353	* After decapsulation, packet is going to re-enter (netif_rx()) our stack,
	354	* so make some cleanups. (no accounting done)
	355	*/
ea23192e ND	356	static inline void __skb_tunnel_rx(struct sk_buff skb, struct net_device dev,
ea23192e ND	357	struct net *net)
290b895e ED	358	{
290b895e ED	359	skb->dev = dev;
bdeab991 TH	360
bdeab991 TH	361	/*
7539fadc	362	* Clear hash so that we can recalulate the hash for the
bdeab991 TH	363	* encapsulated packet, unless we have already determine the hash
	364	* over the L4 4-tuple.
	365	*/
7539fadc	366	skb_clear_hash_if_not_l4(skb);
290b895e	367	skb_set_queue_mapping(skb, 0);
ea23192e	368	skb_scrub_packet(skb, !net_eq(net, dev_net(dev)));
290b895e ED	369	}
290b895e ED	370
d19d56dd ED	371	/**
	372	* skb_tunnel_rx - prepare skb for rx reinsert
	373	* @skb: buffer
	374	* @dev: tunnel device
	375	*
	376	* After decapsulation, packet is going to re-enter (netif_rx()) our stack,
	377	* so make some cleanups, and perform accounting.
290b895e	378	* Note: this accounting is not SMP safe.
d19d56dd	379	*/
ea23192e ND	380	static inline void skb_tunnel_rx(struct sk_buff skb, struct net_device dev,
ea23192e ND	381	struct net *net)
d19d56dd	382	{
d19d56dd ED	383	/* TODO : stats should be SMP safe */
	384	dev->stats.rx_packets++;
	385	dev->stats.rx_bytes += skb->len;
ea23192e	386	__skb_tunnel_rx(skb, dev, net);
d19d56dd ED	387	}
d19d56dd ED	388
808c1b69 DB	389	static inline u32 dst_tclassid(const struct sk_buff *skb)
	390	{
	391	#ifdef CONFIG_IP_ROUTE_CLASSID
	392	const struct dst_entry *dst;
	393
	394	dst = skb_dst(skb);
	395	if (dst)
	396	return dst->tclassid;
	397	#endif
	398	return 0;
	399	}
	400
ede2059d	401	int dst_discard_out(struct net net, struct sock sk, struct sk_buff *skb);
aad88724 ED	402	static inline int dst_discard(struct sk_buff *skb)
aad88724 ED	403	{
ede2059d	404	return dst_discard_out(&init_net, skb->sk, skb);
aad88724	405	}
a4023dd0 JP	406	void dst_alloc(struct dst_ops ops, struct net_device *dev, int initial_ref,
a4023dd0 JP	407	int initial_obsolete, unsigned short flags);
f38a9eb1 TG	408	void dst_init(struct dst_entry dst, struct dst_ops ops,
	409	struct net_device *dev, int initial_ref, int initial_obsolete,
	410	unsigned short flags);
a4023dd0	411	struct dst_entry dst_destroy(struct dst_entry dst);
4a6ce2b6	412	void dst_dev_put(struct dst_entry *dst);
1da177e4	413
1da177e4 LT	414	static inline void dst_confirm(struct dst_entry *dst)
1da177e4 LT	415	{
5110effe	416	}
f2c31e32	417
d3aaeb38 DM	418	static inline struct neighbour dst_neigh_lookup(const struct dst_entry dst, const void *daddr)
d3aaeb38 DM	419	{
aaa0c23c ZZ	420	struct neighbour *n = dst->ops->neigh_lookup(dst, NULL, daddr);
aaa0c23c ZZ	421	return IS_ERR(n) ? NULL : n;
f894cbf8 DM	422	}
	423
	424	static inline struct neighbour dst_neigh_lookup_skb(const struct dst_entry dst,
	425	struct sk_buff *skb)
	426	{
aaa0c23c ZZ	427	struct neighbour *n = dst->ops->neigh_lookup(dst, skb, NULL);
aaa0c23c ZZ	428	return IS_ERR(n) ? NULL : n;
d3aaeb38 DM	429	}
d3aaeb38 DM	430
63fca65d JA	431	static inline void dst_confirm_neigh(const struct dst_entry *dst,
	432	const void *daddr)
	433	{
	434	if (dst->ops->confirm_neigh)
	435	dst->ops->confirm_neigh(dst, daddr);
	436	}
	437
1da177e4 LT	438	static inline void dst_link_failure(struct sk_buff *skb)
1da177e4 LT	439	{
adf30907	440	struct dst_entry *dst = skb_dst(skb);
1da177e4 LT	441	if (dst && dst->ops && dst->ops->link_failure)
	442	dst->ops->link_failure(skb);
	443	}
	444
	445	static inline void dst_set_expires(struct dst_entry *dst, int timeout)
	446	{
	447	unsigned long expires = jiffies + timeout;
	448
	449	if (expires == 0)
	450	expires = 1;
	451
	452	if (dst->expires == 0 \|\| time_before(expires, dst->expires))
	453	dst->expires = expires;
	454	}
	455
	456	/* Output packet to network from transport. */
13206b6b	457	static inline int dst_output(struct net net, struct sock sk, struct sk_buff *skb)
aad88724	458	{
ede2059d	459	return skb_dst(skb)->output(net, sk, skb);
aad88724	460	}
1da177e4 LT	461
	462	/* Input packet from network to transport. */
	463	static inline int dst_input(struct sk_buff *skb)
	464	{
adf30907	465	return skb_dst(skb)->input(skb);
1da177e4 LT	466	}
	467
	468	static inline struct dst_entry dst_check(struct dst_entry dst, u32 cookie)
	469	{
	470	if (dst->obsolete)
	471	dst = dst->ops->check(dst, cookie);
	472	return dst;
	473	}
	474
815f4e57 HX	475	/* Flags for xfrm_lookup flags argument. */
815f4e57 HX	476	enum {
80c0bc9e	477	XFRM_LOOKUP_ICMP = 1 << 0,
b8c203b2	478	XFRM_LOOKUP_QUEUE = 1 << 1,
ac37e251	479	XFRM_LOOKUP_KEEP_DST_REF = 1 << 2,
815f4e57 HX	480	};
815f4e57 HX	481
1da177e4 LT	482	struct flowi;
1da177e4 LT	483	#ifndef CONFIG_XFRM
452edd59 DM	484	static inline struct dst_entry xfrm_lookup(struct net net,
452edd59 DM	485	struct dst_entry *dst_orig,
6f9c9615 ED	486	const struct flowi *fl,
6f9c9615 ED	487	const struct sock *sk,
452edd59	488	int flags)
1da177e4	489	{
452edd59	490	return dst_orig;
f92ee619 SK	491	}
	492
	493	static inline struct dst_entry xfrm_lookup_route(struct net net,
	494	struct dst_entry *dst_orig,
	495	const struct flowi *fl,
6f9c9615	496	const struct sock *sk,
f92ee619 SK	497	int flags)
	498	{
	499	return dst_orig;
	500	}
e87b3998 VY	501
	502	static inline struct xfrm_state dst_xfrm(const struct dst_entry dst)
	503	{
	504	return NULL;
	505	}
	506
1da177e4	507	#else
a4023dd0	508	struct dst_entry xfrm_lookup(struct net net, struct dst_entry *dst_orig,
6f9c9615	509	const struct flowi fl, const struct sock sk,
a4023dd0	510	int flags);
e87b3998	511
f92ee619	512	struct dst_entry xfrm_lookup_route(struct net net, struct dst_entry *dst_orig,
6f9c9615	513	const struct flowi fl, const struct sock sk,
f92ee619 SK	514	int flags);
f92ee619 SK	515
e87b3998 VY	516	/* skb attached with this dst needs transformation if dst->xfrm is valid */
	517	static inline struct xfrm_state dst_xfrm(const struct dst_entry dst)
	518	{
	519	return dst->xfrm;
	520	}
1da177e4	521	#endif
1da177e4 LT	522
1da177e4 LT	523	#endif /* _NET_DST_H */