2 * net/dst.h Protocol independent destination cache definitions.
4 * Authors: Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
11 #include <net/dst_ops.h>
12 #include <linux/netdevice.h>
13 #include <linux/rtnetlink.h>
14 #include <linux/rcupdate.h>
15 #include <linux/jiffies.h>
16 #include <net/neighbour.h>
17 #include <asm/processor.h>
19 #define DST_GC_MIN (HZ/10)
20 #define DST_GC_INC (HZ/2)
21 #define DST_GC_MAX (120*HZ)
23 /* Each dst_entry has reference count and sits in some parent list(s).
24 * When it is removed from parent list, it is "freed" (dst_free).
25 * After this it enters dead state (dst->obsolete > 0) and if its refcnt
26 * is zero, it can be destroyed immediately, otherwise it is added
27 * to gc list and garbage collector periodically checks the refcnt.
33 struct rcu_head rcu_head
;
34 struct dst_entry
*child
;
35 struct net_device
*dev
;
37 unsigned long _metrics
;
38 unsigned long expires
;
39 struct dst_entry
*path
;
40 struct neighbour
*neighbour
;
43 struct xfrm_state
*xfrm
;
47 int (*input
)(struct sk_buff
*);
48 int (*output
)(struct sk_buff
*);
52 unsigned short header_len
; /* more space at head required */
53 unsigned short trailer_len
; /* space to reserve at tail */
54 #ifdef CONFIG_IP_ROUTE_CLASSID
61 * Align __refcnt to a 64 bytes alignment
62 * (L1_CACHE_SIZE would be too much)
65 long __pad_to_align_refcnt
[1];
68 * __refcnt wants to be on a different cache line from
69 * input/output/ops or performance tanks badly
71 atomic_t __refcnt
; /* client references */
73 unsigned long lastuse
;
75 #define DST_HOST 0x0001
76 #define DST_NOXFRM 0x0002
77 #define DST_NOPOLICY 0x0004
78 #define DST_NOHASH 0x0008
79 #define DST_NOCACHE 0x0010
81 struct dst_entry
*next
;
82 struct rtable __rcu
*rt_next
;
83 struct rt6_info
*rt6_next
;
84 struct dn_route __rcu
*dn_next
;
88 extern u32
*dst_cow_metrics_generic(struct dst_entry
*dst
, unsigned long old
);
89 extern const u32 dst_default_metrics
[RTAX_MAX
];
91 #define DST_METRICS_READ_ONLY 0x1UL
92 #define __DST_METRICS_PTR(Y) \
93 ((u32 *)((Y) & ~DST_METRICS_READ_ONLY))
94 #define DST_METRICS_PTR(X) __DST_METRICS_PTR((X)->_metrics)
96 static inline bool dst_metrics_read_only(const struct dst_entry
*dst
)
98 return dst
->_metrics
& DST_METRICS_READ_ONLY
;
101 extern void __dst_destroy_metrics_generic(struct dst_entry
*dst
, unsigned long old
);
103 static inline void dst_destroy_metrics_generic(struct dst_entry
*dst
)
105 unsigned long val
= dst
->_metrics
;
106 if (!(val
& DST_METRICS_READ_ONLY
))
107 __dst_destroy_metrics_generic(dst
, val
);
110 static inline u32
*dst_metrics_write_ptr(struct dst_entry
*dst
)
112 unsigned long p
= dst
->_metrics
;
116 if (p
& DST_METRICS_READ_ONLY
)
117 return dst
->ops
->cow_metrics(dst
, p
);
118 return __DST_METRICS_PTR(p
);
121 /* This may only be invoked before the entry has reached global
124 static inline void dst_init_metrics(struct dst_entry
*dst
,
125 const u32
*src_metrics
,
128 dst
->_metrics
= ((unsigned long) src_metrics
) |
129 (read_only
? DST_METRICS_READ_ONLY
: 0);
132 static inline void dst_copy_metrics(struct dst_entry
*dest
, const struct dst_entry
*src
)
134 u32
*dst_metrics
= dst_metrics_write_ptr(dest
);
137 u32
*src_metrics
= DST_METRICS_PTR(src
);
139 memcpy(dst_metrics
, src_metrics
, RTAX_MAX
* sizeof(u32
));
143 static inline u32
*dst_metrics_ptr(struct dst_entry
*dst
)
145 return DST_METRICS_PTR(dst
);
149 dst_metric_raw(const struct dst_entry
*dst
, const int metric
)
151 u32
*p
= DST_METRICS_PTR(dst
);
157 dst_metric(const struct dst_entry
*dst
, const int metric
)
159 WARN_ON_ONCE(metric
== RTAX_HOPLIMIT
||
160 metric
== RTAX_ADVMSS
||
162 return dst_metric_raw(dst
, metric
);
166 dst_metric_advmss(const struct dst_entry
*dst
)
168 u32 advmss
= dst_metric_raw(dst
, RTAX_ADVMSS
);
171 advmss
= dst
->ops
->default_advmss(dst
);
176 static inline void dst_metric_set(struct dst_entry
*dst
, int metric
, u32 val
)
178 u32
*p
= dst_metrics_write_ptr(dst
);
185 dst_feature(const struct dst_entry
*dst
, u32 feature
)
187 return dst_metric(dst
, RTAX_FEATURES
) & feature
;
190 static inline u32
dst_mtu(const struct dst_entry
*dst
)
192 u32 mtu
= dst_metric_raw(dst
, RTAX_MTU
);
195 mtu
= dst
->ops
->default_mtu(dst
);
200 /* RTT metrics are stored in milliseconds for user ABI, but used as jiffies */
201 static inline unsigned long dst_metric_rtt(const struct dst_entry
*dst
, int metric
)
203 return msecs_to_jiffies(dst_metric(dst
, metric
));
206 static inline void set_dst_metric_rtt(struct dst_entry
*dst
, int metric
,
209 dst_metric_set(dst
, metric
, jiffies_to_msecs(rtt
));
213 dst_allfrag(const struct dst_entry
*dst
)
215 int ret
= dst_feature(dst
, RTAX_FEATURE_ALLFRAG
);
220 dst_metric_locked(const struct dst_entry
*dst
, int metric
)
222 return dst_metric(dst
, RTAX_LOCK
) & (1<<metric
);
225 static inline void dst_hold(struct dst_entry
* dst
)
228 * If your kernel compilation stops here, please check
229 * __pad_to_align_refcnt declaration in struct dst_entry
231 BUILD_BUG_ON(offsetof(struct dst_entry
, __refcnt
) & 63);
232 atomic_inc(&dst
->__refcnt
);
235 static inline void dst_use(struct dst_entry
*dst
, unsigned long time
)
242 static inline void dst_use_noref(struct dst_entry
*dst
, unsigned long time
)
249 struct dst_entry
* dst_clone(struct dst_entry
* dst
)
252 atomic_inc(&dst
->__refcnt
);
256 extern void dst_release(struct dst_entry
*dst
);
258 static inline void refdst_drop(unsigned long refdst
)
260 if (!(refdst
& SKB_DST_NOREF
))
261 dst_release((struct dst_entry
*)(refdst
& SKB_DST_PTRMASK
));
265 * skb_dst_drop - drops skb dst
268 * Drops dst reference count if a reference was taken.
270 static inline void skb_dst_drop(struct sk_buff
*skb
)
272 if (skb
->_skb_refdst
) {
273 refdst_drop(skb
->_skb_refdst
);
274 skb
->_skb_refdst
= 0UL;
278 static inline void skb_dst_copy(struct sk_buff
*nskb
, const struct sk_buff
*oskb
)
280 nskb
->_skb_refdst
= oskb
->_skb_refdst
;
281 if (!(nskb
->_skb_refdst
& SKB_DST_NOREF
))
282 dst_clone(skb_dst(nskb
));
286 * skb_dst_force - makes sure skb dst is refcounted
289 * If dst is not yet refcounted, let's do it
291 static inline void skb_dst_force(struct sk_buff
*skb
)
293 if (skb_dst_is_noref(skb
)) {
294 WARN_ON(!rcu_read_lock_held());
295 skb
->_skb_refdst
&= ~SKB_DST_NOREF
;
296 dst_clone(skb_dst(skb
));
302 * __skb_tunnel_rx - prepare skb for rx reinsert
304 * @dev: tunnel device
306 * After decapsulation, packet is going to re-enter (netif_rx()) our stack,
307 * so make some cleanups. (no accounting done)
309 static inline void __skb_tunnel_rx(struct sk_buff
*skb
, struct net_device
*dev
)
313 skb_set_queue_mapping(skb
, 0);
319 * skb_tunnel_rx - prepare skb for rx reinsert
321 * @dev: tunnel device
323 * After decapsulation, packet is going to re-enter (netif_rx()) our stack,
324 * so make some cleanups, and perform accounting.
325 * Note: this accounting is not SMP safe.
327 static inline void skb_tunnel_rx(struct sk_buff
*skb
, struct net_device
*dev
)
329 /* TODO : stats should be SMP safe */
330 dev
->stats
.rx_packets
++;
331 dev
->stats
.rx_bytes
+= skb
->len
;
332 __skb_tunnel_rx(skb
, dev
);
335 /* Children define the path of the packet through the
336 * Linux networking. Thus, destinations are stackable.
339 static inline struct dst_entry
*skb_dst_pop(struct sk_buff
*skb
)
341 struct dst_entry
*child
= dst_clone(skb_dst(skb
)->child
);
347 extern int dst_discard(struct sk_buff
*skb
);
348 extern void *dst_alloc(struct dst_ops
* ops
, struct net_device
*dev
,
349 int initial_ref
, int initial_obsolete
, int flags
);
350 extern void __dst_free(struct dst_entry
* dst
);
351 extern struct dst_entry
*dst_destroy(struct dst_entry
* dst
);
353 static inline void dst_free(struct dst_entry
* dst
)
355 if (dst
->obsolete
> 1)
357 if (!atomic_read(&dst
->__refcnt
)) {
358 dst
= dst_destroy(dst
);
365 static inline void dst_rcu_free(struct rcu_head
*head
)
367 struct dst_entry
*dst
= container_of(head
, struct dst_entry
, rcu_head
);
371 static inline void dst_confirm(struct dst_entry
*dst
)
374 neigh_confirm(dst
->neighbour
);
377 static inline void dst_link_failure(struct sk_buff
*skb
)
379 struct dst_entry
*dst
= skb_dst(skb
);
380 if (dst
&& dst
->ops
&& dst
->ops
->link_failure
)
381 dst
->ops
->link_failure(skb
);
384 static inline void dst_set_expires(struct dst_entry
*dst
, int timeout
)
386 unsigned long expires
= jiffies
+ timeout
;
391 if (dst
->expires
== 0 || time_before(expires
, dst
->expires
))
392 dst
->expires
= expires
;
395 /* Output packet to network from transport. */
396 static inline int dst_output(struct sk_buff
*skb
)
398 return skb_dst(skb
)->output(skb
);
401 /* Input packet from network to transport. */
402 static inline int dst_input(struct sk_buff
*skb
)
404 return skb_dst(skb
)->input(skb
);
407 static inline struct dst_entry
*dst_check(struct dst_entry
*dst
, u32 cookie
)
410 dst
= dst
->ops
->check(dst
, cookie
);
414 extern void dst_init(void);
416 /* Flags for xfrm_lookup flags argument. */
418 XFRM_LOOKUP_ICMP
= 1 << 0,
423 static inline struct dst_entry
*xfrm_lookup(struct net
*net
,
424 struct dst_entry
*dst_orig
,
425 const struct flowi
*fl
, struct sock
*sk
,
431 extern struct dst_entry
*xfrm_lookup(struct net
*net
, struct dst_entry
*dst_orig
,
432 const struct flowi
*fl
, struct sock
*sk
,
436 #endif /* _NET_DST_H */