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 struct dst_entry *dst_clone(struct dst_entry *dst)
245 void dst_release(struct dst_entry *dst);
247 void dst_release_immediate(struct dst_entry *dst);
249 static inline void refdst_drop(unsigned long refdst)
251 if (!(refdst & SKB_DST_NOREF))
252 dst_release((struct dst_entry *)(refdst & SKB_DST_PTRMASK));
256 * skb_dst_drop - drops skb dst
259 * Drops dst reference count if a reference was taken.
261 static inline void skb_dst_drop(struct sk_buff *skb)
263 if (skb->_skb_refdst) {
264 refdst_drop(skb->_skb_refdst);
265 skb->_skb_refdst = 0UL;
269 static inline void __skb_dst_copy(struct sk_buff *nskb, unsigned long refdst)
271 nskb->_skb_refdst = refdst;
272 if (!(nskb->_skb_refdst & SKB_DST_NOREF))
273 dst_clone(skb_dst(nskb));
276 static inline void skb_dst_copy(struct sk_buff *nskb, const struct sk_buff *oskb)
278 __skb_dst_copy(nskb, oskb->_skb_refdst);
282 * dst_hold_safe - Take a reference on a dst if possible
283 * @dst: pointer to dst entry
285 * This helper returns false if it could not safely
286 * take a reference on a dst.
288 static inline bool dst_hold_safe(struct dst_entry *dst)
290 return atomic_inc_not_zero(&dst->__refcnt);
294 * skb_dst_force - makes sure skb dst is refcounted
297 * If dst is not yet refcounted and not destroyed, grab a ref on it.
298 * Returns true if dst is refcounted.
300 static inline bool skb_dst_force(struct sk_buff *skb)
302 if (skb_dst_is_noref(skb)) {
303 struct dst_entry *dst = skb_dst(skb);
305 WARN_ON(!rcu_read_lock_held());
306 if (!dst_hold_safe(dst))
309 skb->_skb_refdst = (unsigned long)dst;
312 return skb->_skb_refdst != 0UL;
317 * __skb_tunnel_rx - prepare skb for rx reinsert
319 * @dev: tunnel device
320 * @net: netns for packet i/o
322 * After decapsulation, packet is going to re-enter (netif_rx()) our stack,
323 * so make some cleanups. (no accounting done)
325 static inline void __skb_tunnel_rx(struct sk_buff *skb, struct net_device *dev,
331 * Clear hash so that we can recalulate the hash for the
332 * encapsulated packet, unless we have already determine the hash
333 * over the L4 4-tuple.
335 skb_clear_hash_if_not_l4(skb);
336 skb_set_queue_mapping(skb, 0);
337 skb_scrub_packet(skb, !net_eq(net, dev_net(dev)));
341 * skb_tunnel_rx - prepare skb for rx reinsert
343 * @dev: tunnel device
344 * @net: netns for packet i/o
346 * After decapsulation, packet is going to re-enter (netif_rx()) our stack,
347 * so make some cleanups, and perform accounting.
348 * Note: this accounting is not SMP safe.
350 static inline void skb_tunnel_rx(struct sk_buff *skb, struct net_device *dev,
353 DEV_STATS_INC(dev, rx_packets);
354 DEV_STATS_ADD(dev, rx_bytes, skb->len);
355 __skb_tunnel_rx(skb, dev, net);
358 static inline u32 dst_tclassid(const struct sk_buff *skb)
360 #ifdef CONFIG_IP_ROUTE_CLASSID
361 const struct dst_entry *dst;
365 return dst->tclassid;
370 int dst_discard_out(struct net *net, struct sock *sk, struct sk_buff *skb);
371 static inline int dst_discard(struct sk_buff *skb)
373 return dst_discard_out(&init_net, skb->sk, skb);
375 void *dst_alloc(struct dst_ops *ops, struct net_device *dev, int initial_ref,
376 int initial_obsolete, unsigned short flags);
377 void dst_init(struct dst_entry *dst, struct dst_ops *ops,
378 struct net_device *dev, int initial_ref, int initial_obsolete,
379 unsigned short flags);
380 struct dst_entry *dst_destroy(struct dst_entry *dst);
381 void dst_dev_put(struct dst_entry *dst);
383 static inline void dst_confirm(struct dst_entry *dst)
387 static inline struct neighbour *dst_neigh_lookup(const struct dst_entry *dst, const void *daddr)
389 struct neighbour *n = dst->ops->neigh_lookup(dst, NULL, daddr);
390 return IS_ERR(n) ? NULL : n;
393 static inline struct neighbour *dst_neigh_lookup_skb(const struct dst_entry *dst,
396 struct neighbour *n = NULL;
398 /* The packets from tunnel devices (eg bareudp) may have only
399 * metadata in the dst pointer of skb. Hence a pointer check of
400 * neigh_lookup is needed.
402 if (dst->ops->neigh_lookup)
403 n = dst->ops->neigh_lookup(dst, skb, NULL);
405 return IS_ERR(n) ? NULL : n;
408 static inline void dst_confirm_neigh(const struct dst_entry *dst,
411 if (dst->ops->confirm_neigh)
412 dst->ops->confirm_neigh(dst, daddr);
415 static inline void dst_link_failure(struct sk_buff *skb)
417 struct dst_entry *dst = skb_dst(skb);
418 if (dst && dst->ops && dst->ops->link_failure)
419 dst->ops->link_failure(skb);
422 static inline void dst_set_expires(struct dst_entry *dst, int timeout)
424 unsigned long expires = jiffies + timeout;
429 if (dst->expires == 0 || time_before(expires, dst->expires))
430 dst->expires = expires;
433 /* Output packet to network from transport. */
434 static inline int dst_output(struct net *net, struct sock *sk, struct sk_buff *skb)
436 return skb_dst(skb)->output(net, sk, skb);
439 /* Input packet from network to transport. */
440 static inline int dst_input(struct sk_buff *skb)
442 return skb_dst(skb)->input(skb);
445 static inline struct dst_entry *dst_check(struct dst_entry *dst, u32 cookie)
448 dst = dst->ops->check(dst, cookie);
452 /* Flags for xfrm_lookup flags argument. */
454 XFRM_LOOKUP_ICMP = 1 << 0,
455 XFRM_LOOKUP_QUEUE = 1 << 1,
456 XFRM_LOOKUP_KEEP_DST_REF = 1 << 2,
461 static inline struct dst_entry *xfrm_lookup(struct net *net,
462 struct dst_entry *dst_orig,
463 const struct flowi *fl,
464 const struct sock *sk,
470 static inline struct dst_entry *
471 xfrm_lookup_with_ifid(struct net *net, struct dst_entry *dst_orig,
472 const struct flowi *fl, const struct sock *sk,
473 int flags, u32 if_id)
478 static inline struct dst_entry *xfrm_lookup_route(struct net *net,
479 struct dst_entry *dst_orig,
480 const struct flowi *fl,
481 const struct sock *sk,
487 static inline struct xfrm_state *dst_xfrm(const struct dst_entry *dst)
493 struct dst_entry *xfrm_lookup(struct net *net, struct dst_entry *dst_orig,
494 const struct flowi *fl, const struct sock *sk,
497 struct dst_entry *xfrm_lookup_with_ifid(struct net *net,
498 struct dst_entry *dst_orig,
499 const struct flowi *fl,
500 const struct sock *sk, int flags,
503 struct dst_entry *xfrm_lookup_route(struct net *net, struct dst_entry *dst_orig,
504 const struct flowi *fl, const 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 static inline void skb_dst_update_pmtu(struct sk_buff *skb, u32 mtu)
516 struct dst_entry *dst = skb_dst(skb);
518 if (dst && dst->ops->update_pmtu)
519 dst->ops->update_pmtu(dst, NULL, skb, mtu, true);
522 /* update dst pmtu but not do neighbor confirm */
523 static inline void skb_dst_update_pmtu_no_confirm(struct sk_buff *skb, u32 mtu)
525 struct dst_entry *dst = skb_dst(skb);
527 if (dst && dst->ops->update_pmtu)
528 dst->ops->update_pmtu(dst, NULL, skb, mtu, false);
531 struct dst_entry *dst_blackhole_check(struct dst_entry *dst, u32 cookie);
532 void dst_blackhole_update_pmtu(struct dst_entry *dst, struct sock *sk,
533 struct sk_buff *skb, u32 mtu, bool confirm_neigh);
534 void dst_blackhole_redirect(struct dst_entry *dst, struct sock *sk,
535 struct sk_buff *skb);
536 u32 *dst_blackhole_cow_metrics(struct dst_entry *dst, unsigned long old);
537 struct neighbour *dst_blackhole_neigh_lookup(const struct dst_entry *dst,
540 unsigned int dst_blackhole_mtu(const struct dst_entry *dst);
542 #endif /* _NET_DST_H */