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>
21 #include <linux/indirect_call_wrapper.h>
26 struct net_device *dev;
28 unsigned long _metrics;
29 unsigned long expires;
31 struct xfrm_state *xfrm;
35 int (*input)(struct sk_buff *);
36 int (*output)(struct net *net, struct sock *sk, struct sk_buff *skb);
39 #define DST_NOXFRM 0x0002
40 #define DST_NOPOLICY 0x0004
41 #define DST_NOCOUNT 0x0008
42 #define DST_FAKE_RTABLE 0x0010
43 #define DST_XFRM_TUNNEL 0x0020
44 #define DST_XFRM_QUEUE 0x0040
45 #define DST_METADATA 0x0080
47 /* A non-zero value of dst->obsolete forces by-hand validation
48 * of the route entry. Positive values are set by the generic
49 * dst layer to indicate that the entry has been forcefully
52 * Negative values are used by the implementation layer code to
53 * force invocation of the dst_ops->check() method.
56 #define DST_OBSOLETE_NONE 0
57 #define DST_OBSOLETE_DEAD 2
58 #define DST_OBSOLETE_FORCE_CHK -1
59 #define DST_OBSOLETE_KILL -2
60 unsigned short header_len; /* more space at head required */
61 unsigned short trailer_len; /* space to reserve at tail */
64 * __refcnt wants to be on a different cache line from
65 * input/output/ops or performance tanks badly
68 atomic_t __refcnt; /* 64-bit offset 64 */
71 unsigned long lastuse;
72 struct lwtunnel_state *lwtstate;
73 struct rcu_head rcu_head;
78 atomic_t __refcnt; /* 32-bit offset 64 */
83 u32 metrics[RTAX_MAX];
85 } __aligned(4); /* Low pointer bits contain DST_METRICS_FLAGS */
86 extern const struct dst_metrics dst_default_metrics;
88 u32 *dst_cow_metrics_generic(struct dst_entry *dst, unsigned long old);
90 #define DST_METRICS_READ_ONLY 0x1UL
91 #define DST_METRICS_REFCOUNTED 0x2UL
92 #define DST_METRICS_FLAGS 0x3UL
93 #define __DST_METRICS_PTR(Y) \
94 ((u32 *)((Y) & ~DST_METRICS_FLAGS))
95 #define DST_METRICS_PTR(X) __DST_METRICS_PTR((X)->_metrics)
97 static inline bool dst_metrics_read_only(const struct dst_entry *dst)
99 return dst->_metrics & DST_METRICS_READ_ONLY;
102 void __dst_destroy_metrics_generic(struct dst_entry *dst, unsigned long old);
104 static inline void dst_destroy_metrics_generic(struct dst_entry *dst)
106 unsigned long val = dst->_metrics;
107 if (!(val & DST_METRICS_READ_ONLY))
108 __dst_destroy_metrics_generic(dst, val);
111 static inline u32 *dst_metrics_write_ptr(struct dst_entry *dst)
113 unsigned long p = dst->_metrics;
117 if (p & DST_METRICS_READ_ONLY)
118 return dst->ops->cow_metrics(dst, p);
119 return __DST_METRICS_PTR(p);
122 /* This may only be invoked before the entry has reached global
125 static inline void dst_init_metrics(struct dst_entry *dst,
126 const u32 *src_metrics,
129 dst->_metrics = ((unsigned long) src_metrics) |
130 (read_only ? DST_METRICS_READ_ONLY : 0);
133 static inline void dst_copy_metrics(struct dst_entry *dest, const struct dst_entry *src)
135 u32 *dst_metrics = dst_metrics_write_ptr(dest);
138 u32 *src_metrics = DST_METRICS_PTR(src);
140 memcpy(dst_metrics, src_metrics, RTAX_MAX * sizeof(u32));
144 static inline u32 *dst_metrics_ptr(struct dst_entry *dst)
146 return DST_METRICS_PTR(dst);
150 dst_metric_raw(const struct dst_entry *dst, const int metric)
152 u32 *p = DST_METRICS_PTR(dst);
158 dst_metric(const struct dst_entry *dst, const int metric)
160 WARN_ON_ONCE(metric == RTAX_HOPLIMIT ||
161 metric == RTAX_ADVMSS ||
163 return dst_metric_raw(dst, metric);
167 dst_metric_advmss(const struct dst_entry *dst)
169 u32 advmss = dst_metric_raw(dst, RTAX_ADVMSS);
172 advmss = dst->ops->default_advmss(dst);
177 static inline void dst_metric_set(struct dst_entry *dst, int metric, u32 val)
179 u32 *p = dst_metrics_write_ptr(dst);
185 /* Kernel-internal feature bits that are unallocated in user space. */
186 #define DST_FEATURE_ECN_CA (1U << 31)
188 #define DST_FEATURE_MASK (DST_FEATURE_ECN_CA)
189 #define DST_FEATURE_ECN_MASK (DST_FEATURE_ECN_CA | RTAX_FEATURE_ECN)
192 dst_feature(const struct dst_entry *dst, u32 feature)
194 return dst_metric(dst, RTAX_FEATURES) & feature;
197 INDIRECT_CALLABLE_DECLARE(unsigned int ip6_mtu(const struct dst_entry *));
198 INDIRECT_CALLABLE_DECLARE(unsigned int ipv4_mtu(const struct dst_entry *));
199 static inline u32 dst_mtu(const struct dst_entry *dst)
201 return INDIRECT_CALL_INET(dst->ops->mtu, ip6_mtu, ipv4_mtu, dst);
204 /* RTT metrics are stored in milliseconds for user ABI, but used as jiffies */
205 static inline unsigned long dst_metric_rtt(const struct dst_entry *dst, int metric)
207 return msecs_to_jiffies(dst_metric(dst, metric));
211 dst_allfrag(const struct dst_entry *dst)
213 int ret = dst_feature(dst, RTAX_FEATURE_ALLFRAG);
218 dst_metric_locked(const struct dst_entry *dst, int metric)
220 return dst_metric(dst, RTAX_LOCK) & (1 << metric);
223 static inline void dst_hold(struct dst_entry *dst)
226 * If your kernel compilation stops here, please check
227 * the placement of __refcnt in struct dst_entry
229 BUILD_BUG_ON(offsetof(struct dst_entry, __refcnt) & 63);
230 WARN_ON(atomic_inc_not_zero(&dst->__refcnt) == 0);
233 static inline void dst_use_noref(struct dst_entry *dst, unsigned long time)
235 if (unlikely(time != dst->lastuse)) {
241 static inline struct dst_entry *dst_clone(struct dst_entry *dst)
248 void dst_release(struct dst_entry *dst);
250 void dst_release_immediate(struct dst_entry *dst);
252 static inline void refdst_drop(unsigned long refdst)
254 if (!(refdst & SKB_DST_NOREF))
255 dst_release((struct dst_entry *)(refdst & SKB_DST_PTRMASK));
259 * skb_dst_drop - drops skb dst
262 * Drops dst reference count if a reference was taken.
264 static inline void skb_dst_drop(struct sk_buff *skb)
266 if (skb->_skb_refdst) {
267 refdst_drop(skb->_skb_refdst);
268 skb->_skb_refdst = 0UL;
272 static inline void __skb_dst_copy(struct sk_buff *nskb, unsigned long refdst)
274 nskb->slow_gro |= !!refdst;
275 nskb->_skb_refdst = refdst;
276 if (!(nskb->_skb_refdst & SKB_DST_NOREF))
277 dst_clone(skb_dst(nskb));
280 static inline void skb_dst_copy(struct sk_buff *nskb, const struct sk_buff *oskb)
282 __skb_dst_copy(nskb, oskb->_skb_refdst);
286 * dst_hold_safe - Take a reference on a dst if possible
287 * @dst: pointer to dst entry
289 * This helper returns false if it could not safely
290 * take a reference on a dst.
292 static inline bool dst_hold_safe(struct dst_entry *dst)
294 return atomic_inc_not_zero(&dst->__refcnt);
298 * skb_dst_force - makes sure skb dst is refcounted
301 * If dst is not yet refcounted and not destroyed, grab a ref on it.
302 * Returns true if dst is refcounted.
304 static inline bool skb_dst_force(struct sk_buff *skb)
306 if (skb_dst_is_noref(skb)) {
307 struct dst_entry *dst = skb_dst(skb);
309 WARN_ON(!rcu_read_lock_held());
310 if (!dst_hold_safe(dst))
313 skb->_skb_refdst = (unsigned long)dst;
314 skb->slow_gro |= !!dst;
317 return skb->_skb_refdst != 0UL;
322 * __skb_tunnel_rx - prepare skb for rx reinsert
324 * @dev: tunnel device
325 * @net: netns for packet i/o
327 * After decapsulation, packet is going to re-enter (netif_rx()) our stack,
328 * so make some cleanups. (no accounting done)
330 static inline void __skb_tunnel_rx(struct sk_buff *skb, struct net_device *dev,
336 * Clear hash so that we can recalulate the hash for the
337 * encapsulated packet, unless we have already determine the hash
338 * over the L4 4-tuple.
340 skb_clear_hash_if_not_l4(skb);
341 skb_set_queue_mapping(skb, 0);
342 skb_scrub_packet(skb, !net_eq(net, dev_net(dev)));
346 * skb_tunnel_rx - prepare skb for rx reinsert
348 * @dev: tunnel device
349 * @net: netns for packet i/o
351 * After decapsulation, packet is going to re-enter (netif_rx()) our stack,
352 * so make some cleanups, and perform accounting.
353 * Note: this accounting is not SMP safe.
355 static inline void skb_tunnel_rx(struct sk_buff *skb, struct net_device *dev,
358 DEV_STATS_INC(dev, rx_packets);
359 DEV_STATS_ADD(dev, rx_bytes, skb->len);
360 __skb_tunnel_rx(skb, dev, net);
363 static inline u32 dst_tclassid(const struct sk_buff *skb)
365 #ifdef CONFIG_IP_ROUTE_CLASSID
366 const struct dst_entry *dst;
370 return dst->tclassid;
375 int dst_discard_out(struct net *net, struct sock *sk, struct sk_buff *skb);
376 static inline int dst_discard(struct sk_buff *skb)
378 return dst_discard_out(&init_net, skb->sk, skb);
380 void *dst_alloc(struct dst_ops *ops, struct net_device *dev, int initial_ref,
381 int initial_obsolete, unsigned short flags);
382 void dst_init(struct dst_entry *dst, struct dst_ops *ops,
383 struct net_device *dev, int initial_ref, int initial_obsolete,
384 unsigned short flags);
385 struct dst_entry *dst_destroy(struct dst_entry *dst);
386 void dst_dev_put(struct dst_entry *dst);
388 static inline void dst_confirm(struct dst_entry *dst)
392 static inline struct neighbour *dst_neigh_lookup(const struct dst_entry *dst, const void *daddr)
394 struct neighbour *n = dst->ops->neigh_lookup(dst, NULL, daddr);
395 return IS_ERR(n) ? NULL : n;
398 static inline struct neighbour *dst_neigh_lookup_skb(const struct dst_entry *dst,
403 if (WARN_ON_ONCE(!dst->ops->neigh_lookup))
406 n = dst->ops->neigh_lookup(dst, skb, NULL);
408 return IS_ERR(n) ? NULL : n;
411 static inline void dst_confirm_neigh(const struct dst_entry *dst,
414 if (dst->ops->confirm_neigh)
415 dst->ops->confirm_neigh(dst, daddr);
418 static inline void dst_link_failure(struct sk_buff *skb)
420 struct dst_entry *dst = skb_dst(skb);
421 if (dst && dst->ops && dst->ops->link_failure)
422 dst->ops->link_failure(skb);
425 static inline void dst_set_expires(struct dst_entry *dst, int timeout)
427 unsigned long expires = jiffies + timeout;
432 if (dst->expires == 0 || time_before(expires, dst->expires))
433 dst->expires = expires;
436 INDIRECT_CALLABLE_DECLARE(int ip6_output(struct net *, struct sock *,
438 INDIRECT_CALLABLE_DECLARE(int ip_output(struct net *, struct sock *,
440 /* Output packet to network from transport. */
441 static inline int dst_output(struct net *net, struct sock *sk, struct sk_buff *skb)
443 return INDIRECT_CALL_INET(skb_dst(skb)->output,
444 ip6_output, ip_output,
448 INDIRECT_CALLABLE_DECLARE(int ip6_input(struct sk_buff *));
449 INDIRECT_CALLABLE_DECLARE(int ip_local_deliver(struct sk_buff *));
450 /* Input packet from network to transport. */
451 static inline int dst_input(struct sk_buff *skb)
453 return INDIRECT_CALL_INET(skb_dst(skb)->input,
454 ip6_input, ip_local_deliver, skb);
457 INDIRECT_CALLABLE_DECLARE(struct dst_entry *ip6_dst_check(struct dst_entry *,
459 INDIRECT_CALLABLE_DECLARE(struct dst_entry *ipv4_dst_check(struct dst_entry *,
461 static inline struct dst_entry *dst_check(struct dst_entry *dst, u32 cookie)
464 dst = INDIRECT_CALL_INET(dst->ops->check, ip6_dst_check,
465 ipv4_dst_check, dst, cookie);
469 /* Flags for xfrm_lookup flags argument. */
471 XFRM_LOOKUP_ICMP = 1 << 0,
472 XFRM_LOOKUP_QUEUE = 1 << 1,
473 XFRM_LOOKUP_KEEP_DST_REF = 1 << 2,
478 static inline struct dst_entry *xfrm_lookup(struct net *net,
479 struct dst_entry *dst_orig,
480 const struct flowi *fl,
481 const struct sock *sk,
487 static inline struct dst_entry *
488 xfrm_lookup_with_ifid(struct net *net, struct dst_entry *dst_orig,
489 const struct flowi *fl, const struct sock *sk,
490 int flags, u32 if_id)
495 static inline struct dst_entry *xfrm_lookup_route(struct net *net,
496 struct dst_entry *dst_orig,
497 const struct flowi *fl,
498 const struct sock *sk,
504 static inline struct xfrm_state *dst_xfrm(const struct dst_entry *dst)
510 struct dst_entry *xfrm_lookup(struct net *net, struct dst_entry *dst_orig,
511 const struct flowi *fl, const struct sock *sk,
514 struct dst_entry *xfrm_lookup_with_ifid(struct net *net,
515 struct dst_entry *dst_orig,
516 const struct flowi *fl,
517 const struct sock *sk, int flags,
520 struct dst_entry *xfrm_lookup_route(struct net *net, struct dst_entry *dst_orig,
521 const struct flowi *fl, const struct sock *sk,
524 /* skb attached with this dst needs transformation if dst->xfrm is valid */
525 static inline struct xfrm_state *dst_xfrm(const struct dst_entry *dst)
531 static inline void skb_dst_update_pmtu(struct sk_buff *skb, u32 mtu)
533 struct dst_entry *dst = skb_dst(skb);
535 if (dst && dst->ops->update_pmtu)
536 dst->ops->update_pmtu(dst, NULL, skb, mtu, true);
539 /* update dst pmtu but not do neighbor confirm */
540 static inline void skb_dst_update_pmtu_no_confirm(struct sk_buff *skb, u32 mtu)
542 struct dst_entry *dst = skb_dst(skb);
544 if (dst && dst->ops->update_pmtu)
545 dst->ops->update_pmtu(dst, NULL, skb, mtu, false);
548 struct dst_entry *dst_blackhole_check(struct dst_entry *dst, u32 cookie);
549 void dst_blackhole_update_pmtu(struct dst_entry *dst, struct sock *sk,
550 struct sk_buff *skb, u32 mtu, bool confirm_neigh);
551 void dst_blackhole_redirect(struct dst_entry *dst, struct sock *sk,
552 struct sk_buff *skb);
553 u32 *dst_blackhole_cow_metrics(struct dst_entry *dst, unsigned long old);
554 struct neighbour *dst_blackhole_neigh_lookup(const struct dst_entry *dst,
557 unsigned int dst_blackhole_mtu(const struct dst_entry *dst);
559 #endif /* _NET_DST_H */