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
80 #define DST_NOCOUNT 0x0020
82 struct dst_entry *next;
83 struct rtable __rcu *rt_next;
84 struct rt6_info *rt6_next;
85 struct dn_route __rcu *dn_next;
89 extern u32 *dst_cow_metrics_generic(struct dst_entry *dst, unsigned long old);
90 extern const u32 dst_default_metrics[RTAX_MAX];
92 #define DST_METRICS_READ_ONLY 0x1UL
93 #define __DST_METRICS_PTR(Y) \
94 ((u32 *)((Y) & ~DST_METRICS_READ_ONLY))
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 extern 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);
186 dst_feature(const struct dst_entry *dst, u32 feature)
188 return dst_metric(dst, RTAX_FEATURES) & feature;
191 static inline u32 dst_mtu(const struct dst_entry *dst)
193 u32 mtu = dst_metric_raw(dst, RTAX_MTU);
196 mtu = dst->ops->default_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));
207 static inline void set_dst_metric_rtt(struct dst_entry *dst, int metric,
210 dst_metric_set(dst, metric, jiffies_to_msecs(rtt));
214 dst_allfrag(const struct dst_entry *dst)
216 int ret = dst_feature(dst, RTAX_FEATURE_ALLFRAG);
221 dst_metric_locked(const struct dst_entry *dst, int metric)
223 return dst_metric(dst, RTAX_LOCK) & (1<<metric);
226 static inline void dst_hold(struct dst_entry * dst)
229 * If your kernel compilation stops here, please check
230 * __pad_to_align_refcnt declaration in struct dst_entry
232 BUILD_BUG_ON(offsetof(struct dst_entry, __refcnt) & 63);
233 atomic_inc(&dst->__refcnt);
236 static inline void dst_use(struct dst_entry *dst, unsigned long time)
243 static inline void dst_use_noref(struct dst_entry *dst, unsigned long time)
250 struct dst_entry * dst_clone(struct dst_entry * dst)
253 atomic_inc(&dst->__refcnt);
257 extern void dst_release(struct dst_entry *dst);
259 static inline void refdst_drop(unsigned long refdst)
261 if (!(refdst & SKB_DST_NOREF))
262 dst_release((struct dst_entry *)(refdst & SKB_DST_PTRMASK));
266 * skb_dst_drop - drops skb dst
269 * Drops dst reference count if a reference was taken.
271 static inline void skb_dst_drop(struct sk_buff *skb)
273 if (skb->_skb_refdst) {
274 refdst_drop(skb->_skb_refdst);
275 skb->_skb_refdst = 0UL;
279 static inline void skb_dst_copy(struct sk_buff *nskb, const struct sk_buff *oskb)
281 nskb->_skb_refdst = oskb->_skb_refdst;
282 if (!(nskb->_skb_refdst & SKB_DST_NOREF))
283 dst_clone(skb_dst(nskb));
287 * skb_dst_force - makes sure skb dst is refcounted
290 * If dst is not yet refcounted, let's do it
292 static inline void skb_dst_force(struct sk_buff *skb)
294 if (skb_dst_is_noref(skb)) {
295 WARN_ON(!rcu_read_lock_held());
296 skb->_skb_refdst &= ~SKB_DST_NOREF;
297 dst_clone(skb_dst(skb));
303 * __skb_tunnel_rx - prepare skb for rx reinsert
305 * @dev: tunnel device
307 * After decapsulation, packet is going to re-enter (netif_rx()) our stack,
308 * so make some cleanups. (no accounting done)
310 static inline void __skb_tunnel_rx(struct sk_buff *skb, struct net_device *dev)
314 skb_set_queue_mapping(skb, 0);
320 * skb_tunnel_rx - prepare skb for rx reinsert
322 * @dev: tunnel device
324 * After decapsulation, packet is going to re-enter (netif_rx()) our stack,
325 * so make some cleanups, and perform accounting.
326 * Note: this accounting is not SMP safe.
328 static inline void skb_tunnel_rx(struct sk_buff *skb, struct net_device *dev)
330 /* TODO : stats should be SMP safe */
331 dev->stats.rx_packets++;
332 dev->stats.rx_bytes += skb->len;
333 __skb_tunnel_rx(skb, dev);
336 /* Children define the path of the packet through the
337 * Linux networking. Thus, destinations are stackable.
340 static inline struct dst_entry *skb_dst_pop(struct sk_buff *skb)
342 struct dst_entry *child = dst_clone(skb_dst(skb)->child);
348 extern int dst_discard(struct sk_buff *skb);
349 extern void *dst_alloc(struct dst_ops * ops, struct net_device *dev,
350 int initial_ref, int initial_obsolete, int flags);
351 extern void __dst_free(struct dst_entry * dst);
352 extern struct dst_entry *dst_destroy(struct dst_entry * dst);
354 static inline void dst_free(struct dst_entry * dst)
356 if (dst->obsolete > 1)
358 if (!atomic_read(&dst->__refcnt)) {
359 dst = dst_destroy(dst);
366 static inline void dst_rcu_free(struct rcu_head *head)
368 struct dst_entry *dst = container_of(head, struct dst_entry, rcu_head);
372 static inline void dst_confirm(struct dst_entry *dst)
375 neigh_confirm(dst->neighbour);
378 static inline void dst_link_failure(struct sk_buff *skb)
380 struct dst_entry *dst = skb_dst(skb);
381 if (dst && dst->ops && dst->ops->link_failure)
382 dst->ops->link_failure(skb);
385 static inline void dst_set_expires(struct dst_entry *dst, int timeout)
387 unsigned long expires = jiffies + timeout;
392 if (dst->expires == 0 || time_before(expires, dst->expires))
393 dst->expires = expires;
396 /* Output packet to network from transport. */
397 static inline int dst_output(struct sk_buff *skb)
399 return skb_dst(skb)->output(skb);
402 /* Input packet from network to transport. */
403 static inline int dst_input(struct sk_buff *skb)
405 return skb_dst(skb)->input(skb);
408 static inline struct dst_entry *dst_check(struct dst_entry *dst, u32 cookie)
411 dst = dst->ops->check(dst, cookie);
415 extern void dst_init(void);
417 /* Flags for xfrm_lookup flags argument. */
419 XFRM_LOOKUP_ICMP = 1 << 0,
424 static inline struct dst_entry *xfrm_lookup(struct net *net,
425 struct dst_entry *dst_orig,
426 const struct flowi *fl, struct sock *sk,
432 extern struct dst_entry *xfrm_lookup(struct net *net, struct dst_entry *dst_orig,
433 const struct flowi *fl, struct sock *sk,
437 #endif /* _NET_DST_H */