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
;
48 #define DST_NOPOLICY 4
50 unsigned long expires
;
52 unsigned short header_len
; /* more space at head required */
53 unsigned short trailer_len
; /* space to reserve at tail */
55 unsigned int rate_tokens
;
56 unsigned long rate_last
; /* rate limiting for ICMP */
58 struct dst_entry
*path
;
60 struct neighbour
*neighbour
;
63 struct xfrm_state
*xfrm
;
67 int (*input
)(struct sk_buff
*);
68 int (*output
)(struct sk_buff
*);
72 u32 metrics
[RTAX_MAX
];
74 #ifdef CONFIG_NET_CLS_ROUTE
82 * Align __refcnt to a 64 bytes alignment
83 * (L1_CACHE_SIZE would be too much)
86 long __pad_to_align_refcnt
[1];
89 * __refcnt wants to be on a different cache line from
90 * input/output/ops or performance tanks badly
92 atomic_t __refcnt
; /* client references */
94 unsigned long lastuse
;
96 struct dst_entry
*next
;
97 struct rtable
*rt_next
;
98 struct rt6_info
*rt6_next
;
99 struct dn_route
*dn_next
;
106 dst_metric(const struct dst_entry
*dst
, int metric
)
108 return dst
->metrics
[metric
-1];
112 dst_feature(const struct dst_entry
*dst
, u32 feature
)
114 return dst_metric(dst
, RTAX_FEATURES
) & feature
;
117 static inline u32
dst_mtu(const struct dst_entry
*dst
)
119 u32 mtu
= dst_metric(dst
, RTAX_MTU
);
121 * Alexey put it here, so ask him about it :)
127 /* RTT metrics are stored in milliseconds for user ABI, but used as jiffies */
128 static inline unsigned long dst_metric_rtt(const struct dst_entry
*dst
, int metric
)
130 return msecs_to_jiffies(dst_metric(dst
, metric
));
133 static inline void set_dst_metric_rtt(struct dst_entry
*dst
, int metric
,
136 dst
->metrics
[metric
-1] = jiffies_to_msecs(rtt
);
140 dst_allfrag(const struct dst_entry
*dst
)
142 int ret
= dst_feature(dst
, RTAX_FEATURE_ALLFRAG
);
143 /* Yes, _exactly_. This is paranoia. */
149 dst_metric_locked(struct dst_entry
*dst
, int metric
)
151 return dst_metric(dst
, RTAX_LOCK
) & (1<<metric
);
154 static inline void dst_hold(struct dst_entry
* dst
)
157 * If your kernel compilation stops here, please check
158 * __pad_to_align_refcnt declaration in struct dst_entry
160 BUILD_BUG_ON(offsetof(struct dst_entry
, __refcnt
) & 63);
161 atomic_inc(&dst
->__refcnt
);
164 static inline void dst_use(struct dst_entry
*dst
, unsigned long time
)
171 static inline void dst_use_noref(struct dst_entry
*dst
, unsigned long time
)
178 struct dst_entry
* dst_clone(struct dst_entry
* dst
)
181 atomic_inc(&dst
->__refcnt
);
185 extern void dst_release(struct dst_entry
*dst
);
187 static inline void refdst_drop(unsigned long refdst
)
189 if (!(refdst
& SKB_DST_NOREF
))
190 dst_release((struct dst_entry
*)(refdst
& SKB_DST_PTRMASK
));
194 * skb_dst_drop - drops skb dst
197 * Drops dst reference count if a reference was taken.
199 static inline void skb_dst_drop(struct sk_buff
*skb
)
201 if (skb
->_skb_refdst
) {
202 refdst_drop(skb
->_skb_refdst
);
203 skb
->_skb_refdst
= 0UL;
207 static inline void skb_dst_copy(struct sk_buff
*nskb
, const struct sk_buff
*oskb
)
209 nskb
->_skb_refdst
= oskb
->_skb_refdst
;
210 if (!(nskb
->_skb_refdst
& SKB_DST_NOREF
))
211 dst_clone(skb_dst(nskb
));
215 * skb_dst_force - makes sure skb dst is refcounted
218 * If dst is not yet refcounted, let's do it
220 static inline void skb_dst_force(struct sk_buff
*skb
)
222 if (skb_dst_is_noref(skb
)) {
223 WARN_ON(!rcu_read_lock_held());
224 skb
->_skb_refdst
&= ~SKB_DST_NOREF
;
225 dst_clone(skb_dst(skb
));
231 * skb_tunnel_rx - prepare skb for rx reinsert
233 * @dev: tunnel device
235 * After decapsulation, packet is going to re-enter (netif_rx()) our stack,
236 * so make some cleanups, and perform accounting.
238 static inline void skb_tunnel_rx(struct sk_buff
*skb
, struct net_device
*dev
)
241 /* TODO : stats should be SMP safe */
242 dev
->stats
.rx_packets
++;
243 dev
->stats
.rx_bytes
+= skb
->len
;
245 skb_set_queue_mapping(skb
, 0);
250 /* Children define the path of the packet through the
251 * Linux networking. Thus, destinations are stackable.
254 static inline struct dst_entry
*skb_dst_pop(struct sk_buff
*skb
)
256 struct dst_entry
*child
= skb_dst(skb
)->child
;
262 extern int dst_discard(struct sk_buff
*skb
);
263 extern void * dst_alloc(struct dst_ops
* ops
);
264 extern void __dst_free(struct dst_entry
* dst
);
265 extern struct dst_entry
*dst_destroy(struct dst_entry
* dst
);
267 static inline void dst_free(struct dst_entry
* dst
)
269 if (dst
->obsolete
> 1)
271 if (!atomic_read(&dst
->__refcnt
)) {
272 dst
= dst_destroy(dst
);
279 static inline void dst_rcu_free(struct rcu_head
*head
)
281 struct dst_entry
*dst
= container_of(head
, struct dst_entry
, rcu_head
);
285 static inline void dst_confirm(struct dst_entry
*dst
)
288 neigh_confirm(dst
->neighbour
);
291 static inline void dst_link_failure(struct sk_buff
*skb
)
293 struct dst_entry
*dst
= skb_dst(skb
);
294 if (dst
&& dst
->ops
&& dst
->ops
->link_failure
)
295 dst
->ops
->link_failure(skb
);
298 static inline void dst_set_expires(struct dst_entry
*dst
, int timeout
)
300 unsigned long expires
= jiffies
+ timeout
;
305 if (dst
->expires
== 0 || time_before(expires
, dst
->expires
))
306 dst
->expires
= expires
;
309 /* Output packet to network from transport. */
310 static inline int dst_output(struct sk_buff
*skb
)
312 return skb_dst(skb
)->output(skb
);
315 /* Input packet from network to transport. */
316 static inline int dst_input(struct sk_buff
*skb
)
318 return skb_dst(skb
)->input(skb
);
321 static inline struct dst_entry
*dst_check(struct dst_entry
*dst
, u32 cookie
)
324 dst
= dst
->ops
->check(dst
, cookie
);
328 extern void dst_init(void);
330 /* Flags for xfrm_lookup flags argument. */
332 XFRM_LOOKUP_WAIT
= 1 << 0,
333 XFRM_LOOKUP_ICMP
= 1 << 1,
338 static inline int xfrm_lookup(struct net
*net
, struct dst_entry
**dst_p
,
339 struct flowi
*fl
, struct sock
*sk
, int flags
)
343 static inline int __xfrm_lookup(struct net
*net
, struct dst_entry
**dst_p
,
344 struct flowi
*fl
, struct sock
*sk
, int flags
)
349 extern int xfrm_lookup(struct net
*net
, struct dst_entry
**dst_p
,
350 struct flowi
*fl
, struct sock
*sk
, int flags
);
351 extern int __xfrm_lookup(struct net
*net
, struct dst_entry
**dst_p
,
352 struct flowi
*fl
, struct sock
*sk
, int flags
);
356 #endif /* _NET_DST_H */