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/bug.h>
16 #include <linux/jiffies.h>
17 #include <net/neighbour.h>
18 #include <asm/processor.h>
20 #define DST_GC_MIN (HZ/10)
21 #define DST_GC_INC (HZ/2)
22 #define DST_GC_MAX (120*HZ)
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.
34 struct rcu_head rcu_head
;
35 struct dst_entry
*child
;
36 struct net_device
*dev
;
38 unsigned long _metrics
;
39 unsigned long expires
;
40 struct dst_entry
*path
;
41 struct dst_entry
*from
;
43 struct xfrm_state
*xfrm
;
47 struct lwtunnel_state
*lwtstate
;
48 int (*input
)(struct sk_buff
*);
49 int (*output
)(struct sock
*sk
, struct sk_buff
*skb
);
52 #define DST_HOST 0x0001
53 #define DST_NOXFRM 0x0002
54 #define DST_NOPOLICY 0x0004
55 #define DST_NOHASH 0x0008
56 #define DST_NOCACHE 0x0010
57 #define DST_NOCOUNT 0x0020
58 #define DST_FAKE_RTABLE 0x0040
59 #define DST_XFRM_TUNNEL 0x0080
60 #define DST_XFRM_QUEUE 0x0100
61 #define DST_METADATA 0x0200
63 unsigned short pending_confirm
;
67 /* A non-zero value of dst->obsolete forces by-hand validation
68 * of the route entry. Positive values are set by the generic
69 * dst layer to indicate that the entry has been forcefully
72 * Negative values are used by the implementation layer code to
73 * force invocation of the dst_ops->check() method.
76 #define DST_OBSOLETE_NONE 0
77 #define DST_OBSOLETE_DEAD 2
78 #define DST_OBSOLETE_FORCE_CHK -1
79 #define DST_OBSOLETE_KILL -2
80 unsigned short header_len
; /* more space at head required */
81 unsigned short trailer_len
; /* space to reserve at tail */
82 #ifdef CONFIG_IP_ROUTE_CLASSID
89 * Align __refcnt to a 64 bytes alignment
90 * (L1_CACHE_SIZE would be too much)
93 long __pad_to_align_refcnt
[1];
96 * __refcnt wants to be on a different cache line from
97 * input/output/ops or performance tanks badly
99 atomic_t __refcnt
; /* client references */
101 unsigned long lastuse
;
103 struct dst_entry
*next
;
104 struct rtable __rcu
*rt_next
;
105 struct rt6_info
*rt6_next
;
106 struct dn_route __rcu
*dn_next
;
110 u32
*dst_cow_metrics_generic(struct dst_entry
*dst
, unsigned long old
);
111 extern const u32 dst_default_metrics
[];
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)
119 static inline bool dst_metrics_read_only(const struct dst_entry
*dst
)
121 return dst
->_metrics
& DST_METRICS_READ_ONLY
;
124 void __dst_destroy_metrics_generic(struct dst_entry
*dst
, unsigned long old
);
126 static inline void dst_destroy_metrics_generic(struct dst_entry
*dst
)
128 unsigned long val
= dst
->_metrics
;
129 if (!(val
& DST_METRICS_READ_ONLY
))
130 __dst_destroy_metrics_generic(dst
, val
);
133 static inline u32
*dst_metrics_write_ptr(struct dst_entry
*dst
)
135 unsigned long p
= dst
->_metrics
;
139 if (p
& DST_METRICS_READ_ONLY
)
140 return dst
->ops
->cow_metrics(dst
, p
);
141 return __DST_METRICS_PTR(p
);
144 /* This may only be invoked before the entry has reached global
147 static inline void dst_init_metrics(struct dst_entry
*dst
,
148 const u32
*src_metrics
,
151 dst
->_metrics
= ((unsigned long) src_metrics
) |
152 (read_only
? DST_METRICS_READ_ONLY
: 0);
155 static inline void dst_copy_metrics(struct dst_entry
*dest
, const struct dst_entry
*src
)
157 u32
*dst_metrics
= dst_metrics_write_ptr(dest
);
160 u32
*src_metrics
= DST_METRICS_PTR(src
);
162 memcpy(dst_metrics
, src_metrics
, RTAX_MAX
* sizeof(u32
));
166 static inline u32
*dst_metrics_ptr(struct dst_entry
*dst
)
168 return DST_METRICS_PTR(dst
);
172 dst_metric_raw(const struct dst_entry
*dst
, const int metric
)
174 u32
*p
= DST_METRICS_PTR(dst
);
180 dst_metric(const struct dst_entry
*dst
, const int metric
)
182 WARN_ON_ONCE(metric
== RTAX_HOPLIMIT
||
183 metric
== RTAX_ADVMSS
||
185 return dst_metric_raw(dst
, metric
);
189 dst_metric_advmss(const struct dst_entry
*dst
)
191 u32 advmss
= dst_metric_raw(dst
, RTAX_ADVMSS
);
194 advmss
= dst
->ops
->default_advmss(dst
);
199 static inline void dst_metric_set(struct dst_entry
*dst
, int metric
, u32 val
)
201 u32
*p
= dst_metrics_write_ptr(dst
);
208 dst_feature(const struct dst_entry
*dst
, u32 feature
)
210 return dst_metric(dst
, RTAX_FEATURES
) & feature
;
213 static inline u32
dst_mtu(const struct dst_entry
*dst
)
215 return dst
->ops
->mtu(dst
);
218 /* RTT metrics are stored in milliseconds for user ABI, but used as jiffies */
219 static inline unsigned long dst_metric_rtt(const struct dst_entry
*dst
, int metric
)
221 return msecs_to_jiffies(dst_metric(dst
, metric
));
225 dst_allfrag(const struct dst_entry
*dst
)
227 int ret
= dst_feature(dst
, RTAX_FEATURE_ALLFRAG
);
232 dst_metric_locked(const struct dst_entry
*dst
, int metric
)
234 return dst_metric(dst
, RTAX_LOCK
) & (1<<metric
);
237 static inline void dst_hold(struct dst_entry
*dst
)
240 * If your kernel compilation stops here, please check
241 * __pad_to_align_refcnt declaration in struct dst_entry
243 BUILD_BUG_ON(offsetof(struct dst_entry
, __refcnt
) & 63);
244 atomic_inc(&dst
->__refcnt
);
247 static inline void dst_use(struct dst_entry
*dst
, unsigned long time
)
254 static inline void dst_use_noref(struct dst_entry
*dst
, unsigned long time
)
260 static inline struct dst_entry
*dst_clone(struct dst_entry
*dst
)
263 atomic_inc(&dst
->__refcnt
);
267 void dst_release(struct dst_entry
*dst
);
269 static inline void refdst_drop(unsigned long refdst
)
271 if (!(refdst
& SKB_DST_NOREF
))
272 dst_release((struct dst_entry
*)(refdst
& SKB_DST_PTRMASK
));
276 * skb_dst_drop - drops skb dst
279 * Drops dst reference count if a reference was taken.
281 static inline void skb_dst_drop(struct sk_buff
*skb
)
283 if (skb
->_skb_refdst
) {
284 refdst_drop(skb
->_skb_refdst
);
285 skb
->_skb_refdst
= 0UL;
289 static inline void skb_dst_copy(struct sk_buff
*nskb
, const struct sk_buff
*oskb
)
291 nskb
->_skb_refdst
= oskb
->_skb_refdst
;
292 if (!(nskb
->_skb_refdst
& SKB_DST_NOREF
))
293 dst_clone(skb_dst(nskb
));
297 * skb_dst_force - makes sure skb dst is refcounted
300 * If dst is not yet refcounted, let's do it
302 static inline void skb_dst_force(struct sk_buff
*skb
)
304 if (skb_dst_is_noref(skb
)) {
305 WARN_ON(!rcu_read_lock_held());
306 skb
->_skb_refdst
&= ~SKB_DST_NOREF
;
307 dst_clone(skb_dst(skb
));
313 * __skb_tunnel_rx - prepare skb for rx reinsert
315 * @dev: tunnel device
316 * @net: netns for packet i/o
318 * After decapsulation, packet is going to re-enter (netif_rx()) our stack,
319 * so make some cleanups. (no accounting done)
321 static inline void __skb_tunnel_rx(struct sk_buff
*skb
, struct net_device
*dev
,
327 * Clear hash so that we can recalulate the hash for the
328 * encapsulated packet, unless we have already determine the hash
329 * over the L4 4-tuple.
331 skb_clear_hash_if_not_l4(skb
);
332 skb_set_queue_mapping(skb
, 0);
333 skb_scrub_packet(skb
, !net_eq(net
, dev_net(dev
)));
337 * skb_tunnel_rx - prepare skb for rx reinsert
339 * @dev: tunnel device
341 * After decapsulation, packet is going to re-enter (netif_rx()) our stack,
342 * so make some cleanups, and perform accounting.
343 * Note: this accounting is not SMP safe.
345 static inline void skb_tunnel_rx(struct sk_buff
*skb
, struct net_device
*dev
,
348 /* TODO : stats should be SMP safe */
349 dev
->stats
.rx_packets
++;
350 dev
->stats
.rx_bytes
+= skb
->len
;
351 __skb_tunnel_rx(skb
, dev
, net
);
354 int dst_discard_sk(struct sock
*sk
, struct sk_buff
*skb
);
355 static inline int dst_discard(struct sk_buff
*skb
)
357 return dst_discard_sk(skb
->sk
, skb
);
359 void *dst_alloc(struct dst_ops
*ops
, struct net_device
*dev
, int initial_ref
,
360 int initial_obsolete
, unsigned short flags
);
361 void dst_init(struct dst_entry
*dst
, struct dst_ops
*ops
,
362 struct net_device
*dev
, int initial_ref
, int initial_obsolete
,
363 unsigned short flags
);
364 void __dst_free(struct dst_entry
*dst
);
365 struct dst_entry
*dst_destroy(struct dst_entry
*dst
);
367 static inline void dst_free(struct dst_entry
*dst
)
369 if (dst
->obsolete
> 0)
371 if (!atomic_read(&dst
->__refcnt
)) {
372 dst
= dst_destroy(dst
);
379 static inline void dst_rcu_free(struct rcu_head
*head
)
381 struct dst_entry
*dst
= container_of(head
, struct dst_entry
, rcu_head
);
385 static inline void dst_confirm(struct dst_entry
*dst
)
387 dst
->pending_confirm
= 1;
390 static inline int dst_neigh_output(struct dst_entry
*dst
, struct neighbour
*n
,
393 const struct hh_cache
*hh
;
395 if (dst
->pending_confirm
) {
396 unsigned long now
= jiffies
;
398 dst
->pending_confirm
= 0;
399 /* avoid dirtying neighbour */
400 if (n
->confirmed
!= now
)
405 if ((n
->nud_state
& NUD_CONNECTED
) && hh
->hh_len
)
406 return neigh_hh_output(hh
, skb
);
408 return n
->output(n
, skb
);
411 static inline struct neighbour
*dst_neigh_lookup(const struct dst_entry
*dst
, const void *daddr
)
413 struct neighbour
*n
= dst
->ops
->neigh_lookup(dst
, NULL
, daddr
);
414 return IS_ERR(n
) ? NULL
: n
;
417 static inline struct neighbour
*dst_neigh_lookup_skb(const struct dst_entry
*dst
,
420 struct neighbour
*n
= dst
->ops
->neigh_lookup(dst
, skb
, NULL
);
421 return IS_ERR(n
) ? NULL
: n
;
424 static inline void dst_link_failure(struct sk_buff
*skb
)
426 struct dst_entry
*dst
= skb_dst(skb
);
427 if (dst
&& dst
->ops
&& dst
->ops
->link_failure
)
428 dst
->ops
->link_failure(skb
);
431 static inline void dst_set_expires(struct dst_entry
*dst
, int timeout
)
433 unsigned long expires
= jiffies
+ timeout
;
438 if (dst
->expires
== 0 || time_before(expires
, dst
->expires
))
439 dst
->expires
= expires
;
442 /* Output packet to network from transport. */
443 static inline int dst_output_sk(struct sock
*sk
, struct sk_buff
*skb
)
445 return skb_dst(skb
)->output(sk
, skb
);
447 static inline int dst_output(struct sk_buff
*skb
)
449 return dst_output_sk(skb
->sk
, skb
);
452 /* Input packet from network to transport. */
453 static inline int dst_input(struct sk_buff
*skb
)
455 return skb_dst(skb
)->input(skb
);
458 static inline struct dst_entry
*dst_check(struct dst_entry
*dst
, u32 cookie
)
461 dst
= dst
->ops
->check(dst
, cookie
);
465 void dst_subsys_init(void);
467 /* Flags for xfrm_lookup flags argument. */
469 XFRM_LOOKUP_ICMP
= 1 << 0,
470 XFRM_LOOKUP_QUEUE
= 1 << 1,
471 XFRM_LOOKUP_KEEP_DST_REF
= 1 << 2,
476 static inline struct dst_entry
*xfrm_lookup(struct net
*net
,
477 struct dst_entry
*dst_orig
,
478 const struct flowi
*fl
, struct sock
*sk
,
484 static inline struct dst_entry
*xfrm_lookup_route(struct net
*net
,
485 struct dst_entry
*dst_orig
,
486 const struct flowi
*fl
,
493 static inline struct xfrm_state
*dst_xfrm(const struct dst_entry
*dst
)
499 struct dst_entry
*xfrm_lookup(struct net
*net
, struct dst_entry
*dst_orig
,
500 const struct flowi
*fl
, struct sock
*sk
,
503 struct dst_entry
*xfrm_lookup_route(struct net
*net
, struct dst_entry
*dst_orig
,
504 const struct flowi
*fl
, struct sock
*sk
,
507 /* skb attached with this dst needs transformation if dst->xfrm is valid */
508 static inline struct xfrm_state
*dst_xfrm(const struct dst_entry
*dst
)
514 #endif /* _NET_DST_H */
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