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 int (*input)(struct sk_buff *);
48 int (*output)(struct sock *sk, struct sk_buff *skb);
51 #define DST_HOST 0x0001
52 #define DST_NOXFRM 0x0002
53 #define DST_NOPOLICY 0x0004
54 #define DST_NOHASH 0x0008
55 #define DST_NOCACHE 0x0010
56 #define DST_NOCOUNT 0x0020
57 #define DST_FAKE_RTABLE 0x0040
58 #define DST_XFRM_TUNNEL 0x0080
59 #define DST_XFRM_QUEUE 0x0100
60 #define DST_METADATA 0x0200
62 unsigned short pending_confirm;
66 /* A non-zero value of dst->obsolete forces by-hand validation
67 * of the route entry. Positive values are set by the generic
68 * dst layer to indicate that the entry has been forcefully
71 * Negative values are used by the implementation layer code to
72 * force invocation of the dst_ops->check() method.
75 #define DST_OBSOLETE_NONE 0
76 #define DST_OBSOLETE_DEAD 2
77 #define DST_OBSOLETE_FORCE_CHK -1
78 #define DST_OBSOLETE_KILL -2
79 unsigned short header_len; /* more space at head required */
80 unsigned short trailer_len; /* space to reserve at tail */
81 #ifdef CONFIG_IP_ROUTE_CLASSID
88 * Align __refcnt to a 64 bytes alignment
89 * (L1_CACHE_SIZE would be too much)
92 long __pad_to_align_refcnt[2];
95 * __refcnt wants to be on a different cache line from
96 * input/output/ops or performance tanks badly
98 atomic_t __refcnt; /* client references */
100 unsigned long lastuse;
102 struct dst_entry *next;
103 struct rtable __rcu *rt_next;
104 struct rt6_info *rt6_next;
105 struct dn_route __rcu *dn_next;
109 u32 *dst_cow_metrics_generic(struct dst_entry *dst, unsigned long old);
110 extern const u32 dst_default_metrics[];
112 #define DST_METRICS_READ_ONLY 0x1UL
113 #define DST_METRICS_FLAGS 0x3UL
114 #define __DST_METRICS_PTR(Y) \
115 ((u32 *)((Y) & ~DST_METRICS_FLAGS))
116 #define DST_METRICS_PTR(X) __DST_METRICS_PTR((X)->_metrics)
118 static inline bool dst_metrics_read_only(const struct dst_entry *dst)
120 return dst->_metrics & DST_METRICS_READ_ONLY;
123 void __dst_destroy_metrics_generic(struct dst_entry *dst, unsigned long old);
125 static inline void dst_destroy_metrics_generic(struct dst_entry *dst)
127 unsigned long val = dst->_metrics;
128 if (!(val & DST_METRICS_READ_ONLY))
129 __dst_destroy_metrics_generic(dst, val);
132 static inline u32 *dst_metrics_write_ptr(struct dst_entry *dst)
134 unsigned long p = dst->_metrics;
138 if (p & DST_METRICS_READ_ONLY)
139 return dst->ops->cow_metrics(dst, p);
140 return __DST_METRICS_PTR(p);
143 /* This may only be invoked before the entry has reached global
146 static inline void dst_init_metrics(struct dst_entry *dst,
147 const u32 *src_metrics,
150 dst->_metrics = ((unsigned long) src_metrics) |
151 (read_only ? DST_METRICS_READ_ONLY : 0);
154 static inline void dst_copy_metrics(struct dst_entry *dest, const struct dst_entry *src)
156 u32 *dst_metrics = dst_metrics_write_ptr(dest);
159 u32 *src_metrics = DST_METRICS_PTR(src);
161 memcpy(dst_metrics, src_metrics, RTAX_MAX * sizeof(u32));
165 static inline u32 *dst_metrics_ptr(struct dst_entry *dst)
167 return DST_METRICS_PTR(dst);
171 dst_metric_raw(const struct dst_entry *dst, const int metric)
173 u32 *p = DST_METRICS_PTR(dst);
179 dst_metric(const struct dst_entry *dst, const int metric)
181 WARN_ON_ONCE(metric == RTAX_HOPLIMIT ||
182 metric == RTAX_ADVMSS ||
184 return dst_metric_raw(dst, metric);
188 dst_metric_advmss(const struct dst_entry *dst)
190 u32 advmss = dst_metric_raw(dst, RTAX_ADVMSS);
193 advmss = dst->ops->default_advmss(dst);
198 static inline void dst_metric_set(struct dst_entry *dst, int metric, u32 val)
200 u32 *p = dst_metrics_write_ptr(dst);
207 dst_feature(const struct dst_entry *dst, u32 feature)
209 return dst_metric(dst, RTAX_FEATURES) & feature;
212 static inline u32 dst_mtu(const struct dst_entry *dst)
214 return dst->ops->mtu(dst);
217 /* RTT metrics are stored in milliseconds for user ABI, but used as jiffies */
218 static inline unsigned long dst_metric_rtt(const struct dst_entry *dst, int metric)
220 return msecs_to_jiffies(dst_metric(dst, metric));
224 dst_allfrag(const struct dst_entry *dst)
226 int ret = dst_feature(dst, RTAX_FEATURE_ALLFRAG);
231 dst_metric_locked(const struct dst_entry *dst, int metric)
233 return dst_metric(dst, RTAX_LOCK) & (1<<metric);
236 static inline void dst_hold(struct dst_entry *dst)
239 * If your kernel compilation stops here, please check
240 * __pad_to_align_refcnt declaration in struct dst_entry
242 BUILD_BUG_ON(offsetof(struct dst_entry, __refcnt) & 63);
243 atomic_inc(&dst->__refcnt);
246 static inline void dst_use(struct dst_entry *dst, unsigned long time)
253 static inline void dst_use_noref(struct dst_entry *dst, unsigned long time)
259 static inline struct dst_entry *dst_clone(struct dst_entry *dst)
262 atomic_inc(&dst->__refcnt);
266 void dst_release(struct dst_entry *dst);
268 static inline void refdst_drop(unsigned long refdst)
270 if (!(refdst & SKB_DST_NOREF))
271 dst_release((struct dst_entry *)(refdst & SKB_DST_PTRMASK));
275 * skb_dst_drop - drops skb dst
278 * Drops dst reference count if a reference was taken.
280 static inline void skb_dst_drop(struct sk_buff *skb)
282 if (skb->_skb_refdst) {
283 refdst_drop(skb->_skb_refdst);
284 skb->_skb_refdst = 0UL;
288 static inline void skb_dst_copy(struct sk_buff *nskb, const struct sk_buff *oskb)
290 nskb->_skb_refdst = oskb->_skb_refdst;
291 if (!(nskb->_skb_refdst & SKB_DST_NOREF))
292 dst_clone(skb_dst(nskb));
296 * skb_dst_force - makes sure skb dst is refcounted
299 * If dst is not yet refcounted, let's do it
301 static inline void skb_dst_force(struct sk_buff *skb)
303 if (skb_dst_is_noref(skb)) {
304 WARN_ON(!rcu_read_lock_held());
305 skb->_skb_refdst &= ~SKB_DST_NOREF;
306 dst_clone(skb_dst(skb));
312 * __skb_tunnel_rx - prepare skb for rx reinsert
314 * @dev: tunnel device
315 * @net: netns for packet i/o
317 * After decapsulation, packet is going to re-enter (netif_rx()) our stack,
318 * so make some cleanups. (no accounting done)
320 static inline void __skb_tunnel_rx(struct sk_buff *skb, struct net_device *dev,
326 * Clear hash so that we can recalulate the hash for the
327 * encapsulated packet, unless we have already determine the hash
328 * over the L4 4-tuple.
330 skb_clear_hash_if_not_l4(skb);
331 skb_set_queue_mapping(skb, 0);
332 skb_scrub_packet(skb, !net_eq(net, dev_net(dev)));
336 * skb_tunnel_rx - prepare skb for rx reinsert
338 * @dev: tunnel device
340 * After decapsulation, packet is going to re-enter (netif_rx()) our stack,
341 * so make some cleanups, and perform accounting.
342 * Note: this accounting is not SMP safe.
344 static inline void skb_tunnel_rx(struct sk_buff *skb, struct net_device *dev,
347 /* TODO : stats should be SMP safe */
348 dev->stats.rx_packets++;
349 dev->stats.rx_bytes += skb->len;
350 __skb_tunnel_rx(skb, dev, net);
353 int dst_discard_sk(struct sock *sk, struct sk_buff *skb);
354 static inline int dst_discard(struct sk_buff *skb)
356 return dst_discard_sk(skb->sk, skb);
358 void *dst_alloc(struct dst_ops *ops, struct net_device *dev, int initial_ref,
359 int initial_obsolete, unsigned short flags);
360 void dst_init(struct dst_entry *dst, struct dst_ops *ops,
361 struct net_device *dev, int initial_ref, int initial_obsolete,
362 unsigned short flags);
363 void __dst_free(struct dst_entry *dst);
364 struct dst_entry *dst_destroy(struct dst_entry *dst);
366 static inline void dst_free(struct dst_entry *dst)
368 if (dst->obsolete > 0)
370 if (!atomic_read(&dst->__refcnt)) {
371 dst = dst_destroy(dst);
378 static inline void dst_rcu_free(struct rcu_head *head)
380 struct dst_entry *dst = container_of(head, struct dst_entry, rcu_head);
384 static inline void dst_confirm(struct dst_entry *dst)
386 dst->pending_confirm = 1;
389 static inline int dst_neigh_output(struct dst_entry *dst, struct neighbour *n,
392 const struct hh_cache *hh;
394 if (dst->pending_confirm) {
395 unsigned long now = jiffies;
397 dst->pending_confirm = 0;
398 /* avoid dirtying neighbour */
399 if (n->confirmed != now)
404 if ((n->nud_state & NUD_CONNECTED) && hh->hh_len)
405 return neigh_hh_output(hh, skb);
407 return n->output(n, skb);
410 static inline struct neighbour *dst_neigh_lookup(const struct dst_entry *dst, const void *daddr)
412 struct neighbour *n = dst->ops->neigh_lookup(dst, NULL, daddr);
413 return IS_ERR(n) ? NULL : n;
416 static inline struct neighbour *dst_neigh_lookup_skb(const struct dst_entry *dst,
419 struct neighbour *n = dst->ops->neigh_lookup(dst, skb, NULL);
420 return IS_ERR(n) ? NULL : n;
423 static inline void dst_link_failure(struct sk_buff *skb)
425 struct dst_entry *dst = skb_dst(skb);
426 if (dst && dst->ops && dst->ops->link_failure)
427 dst->ops->link_failure(skb);
430 static inline void dst_set_expires(struct dst_entry *dst, int timeout)
432 unsigned long expires = jiffies + timeout;
437 if (dst->expires == 0 || time_before(expires, dst->expires))
438 dst->expires = expires;
441 /* Output packet to network from transport. */
442 static inline int dst_output_sk(struct sock *sk, struct sk_buff *skb)
444 return skb_dst(skb)->output(sk, skb);
446 static inline int dst_output(struct sk_buff *skb)
448 return dst_output_sk(skb->sk, skb);
451 /* Input packet from network to transport. */
452 static inline int dst_input(struct sk_buff *skb)
454 return skb_dst(skb)->input(skb);
457 static inline struct dst_entry *dst_check(struct dst_entry *dst, u32 cookie)
460 dst = dst->ops->check(dst, cookie);
464 void dst_subsys_init(void);
466 /* Flags for xfrm_lookup flags argument. */
468 XFRM_LOOKUP_ICMP = 1 << 0,
469 XFRM_LOOKUP_QUEUE = 1 << 1,
470 XFRM_LOOKUP_KEEP_DST_REF = 1 << 2,
475 static inline struct dst_entry *xfrm_lookup(struct net *net,
476 struct dst_entry *dst_orig,
477 const struct flowi *fl, struct sock *sk,
483 static inline struct dst_entry *xfrm_lookup_route(struct net *net,
484 struct dst_entry *dst_orig,
485 const struct flowi *fl,
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, struct sock *sk,
502 struct dst_entry *xfrm_lookup_route(struct net *net, struct dst_entry *dst_orig,
503 const struct flowi *fl, struct sock *sk,
506 /* skb attached with this dst needs transformation if dst->xfrm is valid */
507 static inline struct xfrm_state *dst_xfrm(const struct dst_entry *dst)
513 #endif /* _NET_DST_H */