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/jiffies.h>
16 #include <net/neighbour.h>
17 #include <asm/processor.h>
19 #define DST_GC_MIN (HZ/10)
20 #define DST_GC_INC (HZ/2)
21 #define DST_GC_MAX (120*HZ)
23 /* Each dst_entry has reference count and sits in some parent list(s).
24 * When it is removed from parent list, it is "freed" (dst_free).
25 * After this it enters dead state (dst->obsolete > 0) and if its refcnt
26 * is zero, it can be destroyed immediately, otherwise it is added
27 * to gc list and garbage collector periodically checks the refcnt.
33 struct rcu_head rcu_head;
34 struct dst_entry *child;
35 struct net_device *dev;
37 unsigned long _metrics;
38 unsigned long expires;
39 struct dst_entry *path;
40 struct neighbour *neighbour;
43 struct xfrm_state *xfrm;
47 int (*input)(struct sk_buff*);
48 int (*output)(struct sk_buff*);
52 unsigned short header_len; /* more space at head required */
53 unsigned short trailer_len; /* space to reserve at tail */
54 #ifdef CONFIG_IP_ROUTE_CLASSID
61 * Align __refcnt to a 64 bytes alignment
62 * (L1_CACHE_SIZE would be too much)
65 long __pad_to_align_refcnt[1];
68 * __refcnt wants to be on a different cache line from
69 * input/output/ops or performance tanks badly
71 atomic_t __refcnt; /* client references */
73 unsigned long lastuse;
75 #define DST_HOST 0x0001
76 #define DST_NOXFRM 0x0002
77 #define DST_NOPOLICY 0x0004
78 #define DST_NOHASH 0x0008
79 #define DST_NOCACHE 0x0010
81 struct dst_entry *next;
82 struct rtable __rcu *rt_next;
83 struct rt6_info *rt6_next;
84 struct dn_route __rcu *dn_next;
88 extern u32 *dst_cow_metrics_generic(struct dst_entry *dst, unsigned long old);
89 extern const u32 dst_default_metrics[RTAX_MAX];
91 #define DST_METRICS_READ_ONLY 0x1UL
92 #define __DST_METRICS_PTR(Y) \
93 ((u32 *)((Y) & ~DST_METRICS_READ_ONLY))
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 extern 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);
185 dst_feature(const struct dst_entry *dst, u32 feature)
187 return dst_metric(dst, RTAX_FEATURES) & feature;
190 static inline u32 dst_mtu(const struct dst_entry *dst)
192 u32 mtu = dst_metric_raw(dst, RTAX_MTU);
195 mtu = dst->ops->default_mtu(dst);
200 /* RTT metrics are stored in milliseconds for user ABI, but used as jiffies */
201 static inline unsigned long dst_metric_rtt(const struct dst_entry *dst, int metric)
203 return msecs_to_jiffies(dst_metric(dst, metric));
206 static inline void set_dst_metric_rtt(struct dst_entry *dst, int metric,
209 dst_metric_set(dst, metric, jiffies_to_msecs(rtt));
213 dst_allfrag(const struct dst_entry *dst)
215 int ret = dst_feature(dst, RTAX_FEATURE_ALLFRAG);
220 dst_metric_locked(const struct dst_entry *dst, int metric)
222 return dst_metric(dst, RTAX_LOCK) & (1<<metric);
225 static inline void dst_hold(struct dst_entry * dst)
228 * If your kernel compilation stops here, please check
229 * __pad_to_align_refcnt declaration in struct dst_entry
231 BUILD_BUG_ON(offsetof(struct dst_entry, __refcnt) & 63);
232 atomic_inc(&dst->__refcnt);
235 static inline void dst_use(struct dst_entry *dst, unsigned long time)
242 static inline void dst_use_noref(struct dst_entry *dst, unsigned long time)
249 struct dst_entry * dst_clone(struct dst_entry * dst)
252 atomic_inc(&dst->__refcnt);
256 extern void dst_release(struct dst_entry *dst);
258 static inline void refdst_drop(unsigned long refdst)
260 if (!(refdst & SKB_DST_NOREF))
261 dst_release((struct dst_entry *)(refdst & SKB_DST_PTRMASK));
265 * skb_dst_drop - drops skb dst
268 * Drops dst reference count if a reference was taken.
270 static inline void skb_dst_drop(struct sk_buff *skb)
272 if (skb->_skb_refdst) {
273 refdst_drop(skb->_skb_refdst);
274 skb->_skb_refdst = 0UL;
278 static inline void skb_dst_copy(struct sk_buff *nskb, const struct sk_buff *oskb)
280 nskb->_skb_refdst = oskb->_skb_refdst;
281 if (!(nskb->_skb_refdst & SKB_DST_NOREF))
282 dst_clone(skb_dst(nskb));
286 * skb_dst_force - makes sure skb dst is refcounted
289 * If dst is not yet refcounted, let's do it
291 static inline void skb_dst_force(struct sk_buff *skb)
293 if (skb_dst_is_noref(skb)) {
294 WARN_ON(!rcu_read_lock_held());
295 skb->_skb_refdst &= ~SKB_DST_NOREF;
296 dst_clone(skb_dst(skb));
302 * __skb_tunnel_rx - prepare skb for rx reinsert
304 * @dev: tunnel device
306 * After decapsulation, packet is going to re-enter (netif_rx()) our stack,
307 * so make some cleanups. (no accounting done)
309 static inline void __skb_tunnel_rx(struct sk_buff *skb, struct net_device *dev)
313 skb_set_queue_mapping(skb, 0);
319 * skb_tunnel_rx - prepare skb for rx reinsert
321 * @dev: tunnel device
323 * After decapsulation, packet is going to re-enter (netif_rx()) our stack,
324 * so make some cleanups, and perform accounting.
325 * Note: this accounting is not SMP safe.
327 static inline void skb_tunnel_rx(struct sk_buff *skb, struct net_device *dev)
329 /* TODO : stats should be SMP safe */
330 dev->stats.rx_packets++;
331 dev->stats.rx_bytes += skb->len;
332 __skb_tunnel_rx(skb, dev);
335 /* Children define the path of the packet through the
336 * Linux networking. Thus, destinations are stackable.
339 static inline struct dst_entry *skb_dst_pop(struct sk_buff *skb)
341 struct dst_entry *child = dst_clone(skb_dst(skb)->child);
347 extern int dst_discard(struct sk_buff *skb);
348 extern void *dst_alloc(struct dst_ops * ops, struct net_device *dev,
349 int initial_ref, int initial_obsolete, int flags);
350 extern void __dst_free(struct dst_entry * dst);
351 extern struct dst_entry *dst_destroy(struct dst_entry * dst);
353 static inline void dst_free(struct dst_entry * dst)
355 if (dst->obsolete > 1)
357 if (!atomic_read(&dst->__refcnt)) {
358 dst = dst_destroy(dst);
365 static inline void dst_rcu_free(struct rcu_head *head)
367 struct dst_entry *dst = container_of(head, struct dst_entry, rcu_head);
371 static inline void dst_confirm(struct dst_entry *dst)
374 neigh_confirm(dst->neighbour);
377 static inline void dst_link_failure(struct sk_buff *skb)
379 struct dst_entry *dst = skb_dst(skb);
380 if (dst && dst->ops && dst->ops->link_failure)
381 dst->ops->link_failure(skb);
384 static inline void dst_set_expires(struct dst_entry *dst, int timeout)
386 unsigned long expires = jiffies + timeout;
391 if (dst->expires == 0 || time_before(expires, dst->expires))
392 dst->expires = expires;
395 /* Output packet to network from transport. */
396 static inline int dst_output(struct sk_buff *skb)
398 return skb_dst(skb)->output(skb);
401 /* Input packet from network to transport. */
402 static inline int dst_input(struct sk_buff *skb)
404 return skb_dst(skb)->input(skb);
407 static inline struct dst_entry *dst_check(struct dst_entry *dst, u32 cookie)
410 dst = dst->ops->check(dst, cookie);
414 extern void dst_init(void);
416 /* Flags for xfrm_lookup flags argument. */
418 XFRM_LOOKUP_ICMP = 1 << 0,
423 static inline struct dst_entry *xfrm_lookup(struct net *net,
424 struct dst_entry *dst_orig,
425 const struct flowi *fl, struct sock *sk,
431 extern struct dst_entry *xfrm_lookup(struct net *net, struct dst_entry *dst_orig,
432 const struct flowi *fl, struct sock *sk,
436 #endif /* _NET_DST_H */