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>
20 * 0 - no debugging messages
21 * 1 - rare events and bugs (default)
24 #define RT_CACHE_DEBUG 0
26 #define DST_GC_MIN (HZ/10)
27 #define DST_GC_INC (HZ/2)
28 #define DST_GC_MAX (120*HZ)
30 /* Each dst_entry has reference count and sits in some parent list(s).
31 * When it is removed from parent list, it is "freed" (dst_free).
32 * After this it enters dead state (dst->obsolete > 0) and if its refcnt
33 * is zero, it can be destroyed immediately, otherwise it is added
34 * to gc list and garbage collector periodically checks the refcnt.
40 struct rcu_head rcu_head
;
41 struct dst_entry
*child
;
42 struct net_device
*dev
;
44 unsigned long _metrics
;
45 unsigned long expires
;
46 struct dst_entry
*path
;
47 struct neighbour
*neighbour
;
50 struct xfrm_state
*xfrm
;
54 int (*input
)(struct sk_buff
*);
55 int (*output
)(struct sk_buff
*);
59 unsigned short header_len
; /* more space at head required */
60 unsigned short trailer_len
; /* space to reserve at tail */
61 #ifdef CONFIG_IP_ROUTE_CLASSID
68 * Align __refcnt to a 64 bytes alignment
69 * (L1_CACHE_SIZE would be too much)
72 long __pad_to_align_refcnt
[1];
75 * __refcnt wants to be on a different cache line from
76 * input/output/ops or performance tanks badly
78 atomic_t __refcnt
; /* client references */
80 unsigned long lastuse
;
82 #define DST_HOST 0x0001
83 #define DST_NOXFRM 0x0002
84 #define DST_NOPOLICY 0x0004
85 #define DST_NOHASH 0x0008
86 #define DST_NOCACHE 0x0010
88 struct dst_entry
*next
;
89 struct rtable __rcu
*rt_next
;
90 struct rt6_info
*rt6_next
;
91 struct dn_route __rcu
*dn_next
;
95 extern u32
*dst_cow_metrics_generic(struct dst_entry
*dst
, unsigned long old
);
96 extern const u32 dst_default_metrics
[RTAX_MAX
];
98 #define DST_METRICS_READ_ONLY 0x1UL
99 #define __DST_METRICS_PTR(Y) \
100 ((u32 *)((Y) & ~DST_METRICS_READ_ONLY))
101 #define DST_METRICS_PTR(X) __DST_METRICS_PTR((X)->_metrics)
103 static inline bool dst_metrics_read_only(const struct dst_entry
*dst
)
105 return dst
->_metrics
& DST_METRICS_READ_ONLY
;
108 extern void __dst_destroy_metrics_generic(struct dst_entry
*dst
, unsigned long old
);
110 static inline void dst_destroy_metrics_generic(struct dst_entry
*dst
)
112 unsigned long val
= dst
->_metrics
;
113 if (!(val
& DST_METRICS_READ_ONLY
))
114 __dst_destroy_metrics_generic(dst
, val
);
117 static inline u32
*dst_metrics_write_ptr(struct dst_entry
*dst
)
119 unsigned long p
= dst
->_metrics
;
121 if (p
& DST_METRICS_READ_ONLY
)
122 return dst
->ops
->cow_metrics(dst
, p
);
123 return __DST_METRICS_PTR(p
);
126 /* This may only be invoked before the entry has reached global
129 static inline void dst_init_metrics(struct dst_entry
*dst
,
130 const u32
*src_metrics
,
133 dst
->_metrics
= ((unsigned long) src_metrics
) |
134 (read_only
? DST_METRICS_READ_ONLY
: 0);
137 static inline void dst_copy_metrics(struct dst_entry
*dest
, const struct dst_entry
*src
)
139 u32
*dst_metrics
= dst_metrics_write_ptr(dest
);
142 u32
*src_metrics
= DST_METRICS_PTR(src
);
144 memcpy(dst_metrics
, src_metrics
, RTAX_MAX
* sizeof(u32
));
148 static inline u32
*dst_metrics_ptr(struct dst_entry
*dst
)
150 return DST_METRICS_PTR(dst
);
154 dst_metric_raw(const struct dst_entry
*dst
, const int metric
)
156 u32
*p
= DST_METRICS_PTR(dst
);
162 dst_metric(const struct dst_entry
*dst
, const int metric
)
164 WARN_ON_ONCE(metric
== RTAX_HOPLIMIT
||
165 metric
== RTAX_ADVMSS
||
167 return dst_metric_raw(dst
, metric
);
171 dst_metric_advmss(const struct dst_entry
*dst
)
173 u32 advmss
= dst_metric_raw(dst
, RTAX_ADVMSS
);
176 advmss
= dst
->ops
->default_advmss(dst
);
181 static inline void dst_metric_set(struct dst_entry
*dst
, int metric
, u32 val
)
183 u32
*p
= dst_metrics_write_ptr(dst
);
190 dst_feature(const struct dst_entry
*dst
, u32 feature
)
192 return dst_metric(dst
, RTAX_FEATURES
) & feature
;
195 static inline u32
dst_mtu(const struct dst_entry
*dst
)
197 u32 mtu
= dst_metric_raw(dst
, RTAX_MTU
);
200 mtu
= dst
->ops
->default_mtu(dst
);
205 /* RTT metrics are stored in milliseconds for user ABI, but used as jiffies */
206 static inline unsigned long dst_metric_rtt(const struct dst_entry
*dst
, int metric
)
208 return msecs_to_jiffies(dst_metric(dst
, metric
));
211 static inline void set_dst_metric_rtt(struct dst_entry
*dst
, int metric
,
214 dst_metric_set(dst
, metric
, jiffies_to_msecs(rtt
));
218 dst_allfrag(const struct dst_entry
*dst
)
220 int ret
= dst_feature(dst
, RTAX_FEATURE_ALLFRAG
);
225 dst_metric_locked(const struct dst_entry
*dst
, int metric
)
227 return dst_metric(dst
, RTAX_LOCK
) & (1<<metric
);
230 static inline void dst_hold(struct dst_entry
* dst
)
233 * If your kernel compilation stops here, please check
234 * __pad_to_align_refcnt declaration in struct dst_entry
236 BUILD_BUG_ON(offsetof(struct dst_entry
, __refcnt
) & 63);
237 atomic_inc(&dst
->__refcnt
);
240 static inline void dst_use(struct dst_entry
*dst
, unsigned long time
)
247 static inline void dst_use_noref(struct dst_entry
*dst
, unsigned long time
)
254 struct dst_entry
* dst_clone(struct dst_entry
* dst
)
257 atomic_inc(&dst
->__refcnt
);
261 extern void dst_release(struct dst_entry
*dst
);
263 static inline void refdst_drop(unsigned long refdst
)
265 if (!(refdst
& SKB_DST_NOREF
))
266 dst_release((struct dst_entry
*)(refdst
& SKB_DST_PTRMASK
));
270 * skb_dst_drop - drops skb dst
273 * Drops dst reference count if a reference was taken.
275 static inline void skb_dst_drop(struct sk_buff
*skb
)
277 if (skb
->_skb_refdst
) {
278 refdst_drop(skb
->_skb_refdst
);
279 skb
->_skb_refdst
= 0UL;
283 static inline void skb_dst_copy(struct sk_buff
*nskb
, const struct sk_buff
*oskb
)
285 nskb
->_skb_refdst
= oskb
->_skb_refdst
;
286 if (!(nskb
->_skb_refdst
& SKB_DST_NOREF
))
287 dst_clone(skb_dst(nskb
));
291 * skb_dst_force - makes sure skb dst is refcounted
294 * If dst is not yet refcounted, let's do it
296 static inline void skb_dst_force(struct sk_buff
*skb
)
298 if (skb_dst_is_noref(skb
)) {
299 WARN_ON(!rcu_read_lock_held());
300 skb
->_skb_refdst
&= ~SKB_DST_NOREF
;
301 dst_clone(skb_dst(skb
));
307 * __skb_tunnel_rx - prepare skb for rx reinsert
309 * @dev: tunnel device
311 * After decapsulation, packet is going to re-enter (netif_rx()) our stack,
312 * so make some cleanups. (no accounting done)
314 static inline void __skb_tunnel_rx(struct sk_buff
*skb
, struct net_device
*dev
)
318 skb_set_queue_mapping(skb
, 0);
324 * skb_tunnel_rx - prepare skb for rx reinsert
326 * @dev: tunnel device
328 * After decapsulation, packet is going to re-enter (netif_rx()) our stack,
329 * so make some cleanups, and perform accounting.
330 * Note: this accounting is not SMP safe.
332 static inline void skb_tunnel_rx(struct sk_buff
*skb
, struct net_device
*dev
)
334 /* TODO : stats should be SMP safe */
335 dev
->stats
.rx_packets
++;
336 dev
->stats
.rx_bytes
+= skb
->len
;
337 __skb_tunnel_rx(skb
, dev
);
340 /* Children define the path of the packet through the
341 * Linux networking. Thus, destinations are stackable.
344 static inline struct dst_entry
*skb_dst_pop(struct sk_buff
*skb
)
346 struct dst_entry
*child
= dst_clone(skb_dst(skb
)->child
);
352 extern int dst_discard(struct sk_buff
*skb
);
353 extern void *dst_alloc(struct dst_ops
* ops
, struct net_device
*dev
,
354 int initial_ref
, int initial_obsolete
, int flags
);
355 extern void __dst_free(struct dst_entry
* dst
);
356 extern struct dst_entry
*dst_destroy(struct dst_entry
* dst
);
358 static inline void dst_free(struct dst_entry
* dst
)
360 if (dst
->obsolete
> 1)
362 if (!atomic_read(&dst
->__refcnt
)) {
363 dst
= dst_destroy(dst
);
370 static inline void dst_rcu_free(struct rcu_head
*head
)
372 struct dst_entry
*dst
= container_of(head
, struct dst_entry
, rcu_head
);
376 static inline void dst_confirm(struct dst_entry
*dst
)
379 neigh_confirm(dst
->neighbour
);
382 static inline void dst_link_failure(struct sk_buff
*skb
)
384 struct dst_entry
*dst
= skb_dst(skb
);
385 if (dst
&& dst
->ops
&& dst
->ops
->link_failure
)
386 dst
->ops
->link_failure(skb
);
389 static inline void dst_set_expires(struct dst_entry
*dst
, int timeout
)
391 unsigned long expires
= jiffies
+ timeout
;
396 if (dst
->expires
== 0 || time_before(expires
, dst
->expires
))
397 dst
->expires
= expires
;
400 /* Output packet to network from transport. */
401 static inline int dst_output(struct sk_buff
*skb
)
403 return skb_dst(skb
)->output(skb
);
406 /* Input packet from network to transport. */
407 static inline int dst_input(struct sk_buff
*skb
)
409 return skb_dst(skb
)->input(skb
);
412 static inline struct dst_entry
*dst_check(struct dst_entry
*dst
, u32 cookie
)
415 dst
= dst
->ops
->check(dst
, cookie
);
419 extern void dst_init(void);
421 /* Flags for xfrm_lookup flags argument. */
423 XFRM_LOOKUP_ICMP
= 1 << 0,
428 static inline struct dst_entry
*xfrm_lookup(struct net
*net
,
429 struct dst_entry
*dst_orig
,
430 const struct flowi
*fl
, struct sock
*sk
,
436 extern struct dst_entry
*xfrm_lookup(struct net
*net
, struct dst_entry
*dst_orig
,
437 const struct flowi
*fl
, struct sock
*sk
,
441 #endif /* _NET_DST_H */
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