1 /* SPDX-License-Identifier: GPL-2.0 */
3 * net/dst.h Protocol independent destination cache definitions.
5 * Authors: Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
12 #include <net/dst_ops.h>
13 #include <linux/netdevice.h>
14 #include <linux/rtnetlink.h>
15 #include <linux/rcupdate.h>
16 #include <linux/bug.h>
17 #include <linux/jiffies.h>
18 #include <linux/refcount.h>
19 #include <net/neighbour.h>
20 #include <asm/processor.h>
25 struct net_device
*dev
;
27 unsigned long _metrics
;
28 unsigned long expires
;
30 struct xfrm_state
*xfrm
;
34 int (*input
)(struct sk_buff
*);
35 int (*output
)(struct net
*net
, struct sock
*sk
, struct sk_buff
*skb
);
38 #define DST_NOXFRM 0x0002
39 #define DST_NOPOLICY 0x0004
40 #define DST_NOCOUNT 0x0008
41 #define DST_FAKE_RTABLE 0x0010
42 #define DST_XFRM_TUNNEL 0x0020
43 #define DST_XFRM_QUEUE 0x0040
44 #define DST_METADATA 0x0080
46 /* A non-zero value of dst->obsolete forces by-hand validation
47 * of the route entry. Positive values are set by the generic
48 * dst layer to indicate that the entry has been forcefully
51 * Negative values are used by the implementation layer code to
52 * force invocation of the dst_ops->check() method.
55 #define DST_OBSOLETE_NONE 0
56 #define DST_OBSOLETE_DEAD 2
57 #define DST_OBSOLETE_FORCE_CHK -1
58 #define DST_OBSOLETE_KILL -2
59 unsigned short header_len
; /* more space at head required */
60 unsigned short trailer_len
; /* space to reserve at tail */
63 * __refcnt wants to be on a different cache line from
64 * input/output/ops or performance tanks badly
67 atomic_t __refcnt
; /* 64-bit offset 64 */
70 unsigned long lastuse
;
71 struct lwtunnel_state
*lwtstate
;
72 struct rcu_head rcu_head
;
77 atomic_t __refcnt
; /* 32-bit offset 64 */
82 u32 metrics
[RTAX_MAX
];
84 } __aligned(4); /* Low pointer bits contain DST_METRICS_FLAGS */
85 extern const struct dst_metrics dst_default_metrics
;
87 u32
*dst_cow_metrics_generic(struct dst_entry
*dst
, unsigned long old
);
89 #define DST_METRICS_READ_ONLY 0x1UL
90 #define DST_METRICS_REFCOUNTED 0x2UL
91 #define DST_METRICS_FLAGS 0x3UL
92 #define __DST_METRICS_PTR(Y) \
93 ((u32 *)((Y) & ~DST_METRICS_FLAGS))
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 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
);
184 /* Kernel-internal feature bits that are unallocated in user space. */
185 #define DST_FEATURE_ECN_CA (1U << 31)
187 #define DST_FEATURE_MASK (DST_FEATURE_ECN_CA)
188 #define DST_FEATURE_ECN_MASK (DST_FEATURE_ECN_CA | RTAX_FEATURE_ECN)
191 dst_feature(const struct dst_entry
*dst
, u32 feature
)
193 return dst_metric(dst
, RTAX_FEATURES
) & feature
;
196 static inline u32
dst_mtu(const struct dst_entry
*dst
)
198 return dst
->ops
->mtu(dst
);
201 /* RTT metrics are stored in milliseconds for user ABI, but used as jiffies */
202 static inline unsigned long dst_metric_rtt(const struct dst_entry
*dst
, int metric
)
204 return msecs_to_jiffies(dst_metric(dst
, metric
));
208 dst_allfrag(const struct dst_entry
*dst
)
210 int ret
= dst_feature(dst
, RTAX_FEATURE_ALLFRAG
);
215 dst_metric_locked(const struct dst_entry
*dst
, int metric
)
217 return dst_metric(dst
, RTAX_LOCK
) & (1 << metric
);
220 static inline void dst_hold(struct dst_entry
*dst
)
223 * If your kernel compilation stops here, please check
224 * the placement of __refcnt in struct dst_entry
226 BUILD_BUG_ON(offsetof(struct dst_entry
, __refcnt
) & 63);
227 WARN_ON(atomic_inc_not_zero(&dst
->__refcnt
) == 0);
230 static inline void dst_use_noref(struct dst_entry
*dst
, unsigned long time
)
232 if (unlikely(time
!= dst
->lastuse
)) {
238 static inline void dst_hold_and_use(struct dst_entry
*dst
, unsigned long time
)
241 dst_use_noref(dst
, time
);
244 static inline struct dst_entry
*dst_clone(struct dst_entry
*dst
)
251 void dst_release(struct dst_entry
*dst
);
253 void dst_release_immediate(struct dst_entry
*dst
);
255 static inline void refdst_drop(unsigned long refdst
)
257 if (!(refdst
& SKB_DST_NOREF
))
258 dst_release((struct dst_entry
*)(refdst
& SKB_DST_PTRMASK
));
262 * skb_dst_drop - drops skb dst
265 * Drops dst reference count if a reference was taken.
267 static inline void skb_dst_drop(struct sk_buff
*skb
)
269 if (skb
->_skb_refdst
) {
270 refdst_drop(skb
->_skb_refdst
);
271 skb
->_skb_refdst
= 0UL;
275 static inline void __skb_dst_copy(struct sk_buff
*nskb
, unsigned long refdst
)
277 nskb
->_skb_refdst
= refdst
;
278 if (!(nskb
->_skb_refdst
& SKB_DST_NOREF
))
279 dst_clone(skb_dst(nskb
));
282 static inline void skb_dst_copy(struct sk_buff
*nskb
, const struct sk_buff
*oskb
)
284 __skb_dst_copy(nskb
, oskb
->_skb_refdst
);
288 * dst_hold_safe - Take a reference on a dst if possible
289 * @dst: pointer to dst entry
291 * This helper returns false if it could not safely
292 * take a reference on a dst.
294 static inline bool dst_hold_safe(struct dst_entry
*dst
)
296 return atomic_inc_not_zero(&dst
->__refcnt
);
300 * skb_dst_force - makes sure skb dst is refcounted
303 * If dst is not yet refcounted and not destroyed, grab a ref on it.
304 * Returns true if dst is refcounted.
306 static inline bool skb_dst_force(struct sk_buff
*skb
)
308 if (skb_dst_is_noref(skb
)) {
309 struct dst_entry
*dst
= skb_dst(skb
);
311 WARN_ON(!rcu_read_lock_held());
312 if (!dst_hold_safe(dst
))
315 skb
->_skb_refdst
= (unsigned long)dst
;
318 return skb
->_skb_refdst
!= 0UL;
323 * __skb_tunnel_rx - prepare skb for rx reinsert
325 * @dev: tunnel device
326 * @net: netns for packet i/o
328 * After decapsulation, packet is going to re-enter (netif_rx()) our stack,
329 * so make some cleanups. (no accounting done)
331 static inline void __skb_tunnel_rx(struct sk_buff
*skb
, struct net_device
*dev
,
337 * Clear hash so that we can recalulate the hash for the
338 * encapsulated packet, unless we have already determine the hash
339 * over the L4 4-tuple.
341 skb_clear_hash_if_not_l4(skb
);
342 skb_set_queue_mapping(skb
, 0);
343 skb_scrub_packet(skb
, !net_eq(net
, dev_net(dev
)));
347 * skb_tunnel_rx - prepare skb for rx reinsert
349 * @dev: tunnel device
350 * @net: netns for packet i/o
352 * After decapsulation, packet is going to re-enter (netif_rx()) our stack,
353 * so make some cleanups, and perform accounting.
354 * Note: this accounting is not SMP safe.
356 static inline void skb_tunnel_rx(struct sk_buff
*skb
, struct net_device
*dev
,
359 /* TODO : stats should be SMP safe */
360 dev
->stats
.rx_packets
++;
361 dev
->stats
.rx_bytes
+= skb
->len
;
362 __skb_tunnel_rx(skb
, dev
, net
);
365 static inline u32
dst_tclassid(const struct sk_buff
*skb
)
367 #ifdef CONFIG_IP_ROUTE_CLASSID
368 const struct dst_entry
*dst
;
372 return dst
->tclassid
;
377 int dst_discard_out(struct net
*net
, struct sock
*sk
, struct sk_buff
*skb
);
378 static inline int dst_discard(struct sk_buff
*skb
)
380 return dst_discard_out(&init_net
, skb
->sk
, skb
);
382 void *dst_alloc(struct dst_ops
*ops
, struct net_device
*dev
, int initial_ref
,
383 int initial_obsolete
, unsigned short flags
);
384 void dst_init(struct dst_entry
*dst
, struct dst_ops
*ops
,
385 struct net_device
*dev
, int initial_ref
, int initial_obsolete
,
386 unsigned short flags
);
387 struct dst_entry
*dst_destroy(struct dst_entry
*dst
);
388 void dst_dev_put(struct dst_entry
*dst
);
390 static inline void dst_confirm(struct dst_entry
*dst
)
394 static inline struct neighbour
*dst_neigh_lookup(const struct dst_entry
*dst
, const void *daddr
)
396 struct neighbour
*n
= dst
->ops
->neigh_lookup(dst
, NULL
, daddr
);
397 return IS_ERR(n
) ? NULL
: n
;
400 static inline struct neighbour
*dst_neigh_lookup_skb(const struct dst_entry
*dst
,
405 if (WARN_ON_ONCE(!dst
->ops
->neigh_lookup
))
408 n
= dst
->ops
->neigh_lookup(dst
, skb
, NULL
);
410 return IS_ERR(n
) ? NULL
: n
;
413 static inline void dst_confirm_neigh(const struct dst_entry
*dst
,
416 if (dst
->ops
->confirm_neigh
)
417 dst
->ops
->confirm_neigh(dst
, daddr
);
420 static inline void dst_link_failure(struct sk_buff
*skb
)
422 struct dst_entry
*dst
= skb_dst(skb
);
423 if (dst
&& dst
->ops
&& dst
->ops
->link_failure
)
424 dst
->ops
->link_failure(skb
);
427 static inline void dst_set_expires(struct dst_entry
*dst
, int timeout
)
429 unsigned long expires
= jiffies
+ timeout
;
434 if (dst
->expires
== 0 || time_before(expires
, dst
->expires
))
435 dst
->expires
= expires
;
438 /* Output packet to network from transport. */
439 static inline int dst_output(struct net
*net
, struct sock
*sk
, struct sk_buff
*skb
)
441 return skb_dst(skb
)->output(net
, sk
, skb
);
444 /* Input packet from network to transport. */
445 static inline int dst_input(struct sk_buff
*skb
)
447 return skb_dst(skb
)->input(skb
);
450 static inline struct dst_entry
*dst_check(struct dst_entry
*dst
, u32 cookie
)
453 dst
= dst
->ops
->check(dst
, cookie
);
457 /* Flags for xfrm_lookup flags argument. */
459 XFRM_LOOKUP_ICMP
= 1 << 0,
460 XFRM_LOOKUP_QUEUE
= 1 << 1,
461 XFRM_LOOKUP_KEEP_DST_REF
= 1 << 2,
466 static inline struct dst_entry
*xfrm_lookup(struct net
*net
,
467 struct dst_entry
*dst_orig
,
468 const struct flowi
*fl
,
469 const struct sock
*sk
,
475 static inline struct dst_entry
*
476 xfrm_lookup_with_ifid(struct net
*net
, struct dst_entry
*dst_orig
,
477 const struct flowi
*fl
, const struct sock
*sk
,
478 int flags
, u32 if_id
)
483 static inline struct dst_entry
*xfrm_lookup_route(struct net
*net
,
484 struct dst_entry
*dst_orig
,
485 const struct flowi
*fl
,
486 const struct sock
*sk
,
492 static inline struct xfrm_state
*dst_xfrm(const struct dst_entry
*dst
)
498 struct dst_entry
*xfrm_lookup(struct net
*net
, struct dst_entry
*dst_orig
,
499 const struct flowi
*fl
, const struct sock
*sk
,
502 struct dst_entry
*xfrm_lookup_with_ifid(struct net
*net
,
503 struct dst_entry
*dst_orig
,
504 const struct flowi
*fl
,
505 const struct sock
*sk
, int flags
,
508 struct dst_entry
*xfrm_lookup_route(struct net
*net
, struct dst_entry
*dst_orig
,
509 const struct flowi
*fl
, const struct sock
*sk
,
512 /* skb attached with this dst needs transformation if dst->xfrm is valid */
513 static inline struct xfrm_state
*dst_xfrm(const struct dst_entry
*dst
)
519 static inline void skb_dst_update_pmtu(struct sk_buff
*skb
, u32 mtu
)
521 struct dst_entry
*dst
= skb_dst(skb
);
523 if (dst
&& dst
->ops
->update_pmtu
)
524 dst
->ops
->update_pmtu(dst
, NULL
, skb
, mtu
, true);
527 /* update dst pmtu but not do neighbor confirm */
528 static inline void skb_dst_update_pmtu_no_confirm(struct sk_buff
*skb
, u32 mtu
)
530 struct dst_entry
*dst
= skb_dst(skb
);
532 if (dst
&& dst
->ops
->update_pmtu
)
533 dst
->ops
->update_pmtu(dst
, NULL
, skb
, mtu
, false);
536 #endif /* _NET_DST_H */