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>
20 * 0 - no debugging messages
21 * 1 - rare events and bugs (default)
24 #define RT_CACHE_DEBUG 0
26 #define DST_GC_MIN (HZ/10)
27 #define DST_GC_INC (HZ/2)
28 #define DST_GC_MAX (120*HZ)
30 /* Each dst_entry has reference count and sits in some parent list(s).
31 * When it is removed from parent list, it is "freed" (dst_free).
32 * After this it enters dead state (dst->obsolete > 0) and if its refcnt
33 * is zero, it can be destroyed immediately, otherwise it is added
34 * to gc list and garbage collector periodically checks the refcnt.
40 struct rcu_head rcu_head;
41 struct dst_entry *child;
42 struct net_device *dev;
46 #define DST_HOST 0x0001
47 #define DST_NOXFRM 0x0002
48 #define DST_NOPOLICY 0x0004
49 #define DST_NOHASH 0x0008
50 #define DST_NOCACHE 0x0010
51 unsigned long expires;
53 unsigned short header_len; /* more space at head required */
54 unsigned short trailer_len; /* space to reserve at tail */
56 unsigned int rate_tokens;
57 unsigned long rate_last; /* rate limiting for ICMP */
59 struct dst_entry *path;
61 struct neighbour *neighbour;
64 struct xfrm_state *xfrm;
68 int (*input)(struct sk_buff*);
69 int (*output)(struct sk_buff*);
73 u32 _metrics[RTAX_MAX];
75 #ifdef CONFIG_NET_CLS_ROUTE
83 * Align __refcnt to a 64 bytes alignment
84 * (L1_CACHE_SIZE would be too much)
87 long __pad_to_align_refcnt[1];
90 * __refcnt wants to be on a different cache line from
91 * input/output/ops or performance tanks badly
93 atomic_t __refcnt; /* client references */
95 unsigned long lastuse;
97 struct dst_entry *next;
98 struct rtable __rcu *rt_next;
99 struct rt6_info *rt6_next;
100 struct dn_route __rcu *dn_next;
107 dst_metric_raw(const struct dst_entry *dst, const int metric)
109 return dst->_metrics[metric-1];
113 dst_metric(const struct dst_entry *dst, const int metric)
115 WARN_ON_ONCE(metric == RTAX_HOPLIMIT);
116 return dst_metric_raw(dst, metric);
120 dst_metric_hoplimit(const struct dst_entry *dst)
122 return dst_metric_raw(dst, RTAX_HOPLIMIT);
125 static inline void dst_metric_set(struct dst_entry *dst, int metric, u32 val)
127 dst->_metrics[metric-1] = val;
130 static inline void dst_import_metrics(struct dst_entry *dst, const u32 *src_metrics)
132 memcpy(dst->_metrics, src_metrics, RTAX_MAX * sizeof(u32));
135 static inline void dst_copy_metrics(struct dst_entry *dest, const struct dst_entry *src)
137 dst_import_metrics(dest, src->_metrics);
140 static inline u32 *dst_metrics_ptr(struct dst_entry *dst)
142 return dst->_metrics;
146 dst_feature(const struct dst_entry *dst, u32 feature)
148 return dst_metric(dst, RTAX_FEATURES) & feature;
151 static inline u32 dst_mtu(const struct dst_entry *dst)
153 u32 mtu = dst_metric(dst, RTAX_MTU);
155 * Alexey put it here, so ask him about it :)
161 /* RTT metrics are stored in milliseconds for user ABI, but used as jiffies */
162 static inline unsigned long dst_metric_rtt(const struct dst_entry *dst, int metric)
164 return msecs_to_jiffies(dst_metric(dst, metric));
167 static inline void set_dst_metric_rtt(struct dst_entry *dst, int metric,
170 dst_metric_set(dst, metric, jiffies_to_msecs(rtt));
174 dst_allfrag(const struct dst_entry *dst)
176 int ret = dst_feature(dst, RTAX_FEATURE_ALLFRAG);
177 /* Yes, _exactly_. This is paranoia. */
183 dst_metric_locked(struct dst_entry *dst, int metric)
185 return dst_metric(dst, RTAX_LOCK) & (1<<metric);
188 static inline void dst_hold(struct dst_entry * dst)
191 * If your kernel compilation stops here, please check
192 * __pad_to_align_refcnt declaration in struct dst_entry
194 BUILD_BUG_ON(offsetof(struct dst_entry, __refcnt) & 63);
195 atomic_inc(&dst->__refcnt);
198 static inline void dst_use(struct dst_entry *dst, unsigned long time)
205 static inline void dst_use_noref(struct dst_entry *dst, unsigned long time)
212 struct dst_entry * dst_clone(struct dst_entry * dst)
215 atomic_inc(&dst->__refcnt);
219 extern void dst_release(struct dst_entry *dst);
221 static inline void refdst_drop(unsigned long refdst)
223 if (!(refdst & SKB_DST_NOREF))
224 dst_release((struct dst_entry *)(refdst & SKB_DST_PTRMASK));
228 * skb_dst_drop - drops skb dst
231 * Drops dst reference count if a reference was taken.
233 static inline void skb_dst_drop(struct sk_buff *skb)
235 if (skb->_skb_refdst) {
236 refdst_drop(skb->_skb_refdst);
237 skb->_skb_refdst = 0UL;
241 static inline void skb_dst_copy(struct sk_buff *nskb, const struct sk_buff *oskb)
243 nskb->_skb_refdst = oskb->_skb_refdst;
244 if (!(nskb->_skb_refdst & SKB_DST_NOREF))
245 dst_clone(skb_dst(nskb));
249 * skb_dst_force - makes sure skb dst is refcounted
252 * If dst is not yet refcounted, let's do it
254 static inline void skb_dst_force(struct sk_buff *skb)
256 if (skb_dst_is_noref(skb)) {
257 WARN_ON(!rcu_read_lock_held());
258 skb->_skb_refdst &= ~SKB_DST_NOREF;
259 dst_clone(skb_dst(skb));
265 * __skb_tunnel_rx - prepare skb for rx reinsert
267 * @dev: tunnel device
269 * After decapsulation, packet is going to re-enter (netif_rx()) our stack,
270 * so make some cleanups. (no accounting done)
272 static inline void __skb_tunnel_rx(struct sk_buff *skb, struct net_device *dev)
276 skb_set_queue_mapping(skb, 0);
282 * skb_tunnel_rx - prepare skb for rx reinsert
284 * @dev: tunnel device
286 * After decapsulation, packet is going to re-enter (netif_rx()) our stack,
287 * so make some cleanups, and perform accounting.
288 * Note: this accounting is not SMP safe.
290 static inline void skb_tunnel_rx(struct sk_buff *skb, struct net_device *dev)
292 /* TODO : stats should be SMP safe */
293 dev->stats.rx_packets++;
294 dev->stats.rx_bytes += skb->len;
295 __skb_tunnel_rx(skb, dev);
298 /* Children define the path of the packet through the
299 * Linux networking. Thus, destinations are stackable.
302 static inline struct dst_entry *skb_dst_pop(struct sk_buff *skb)
304 struct dst_entry *child = skb_dst(skb)->child;
310 extern int dst_discard(struct sk_buff *skb);
311 extern void * dst_alloc(struct dst_ops * ops);
312 extern void __dst_free(struct dst_entry * dst);
313 extern struct dst_entry *dst_destroy(struct dst_entry * dst);
315 static inline void dst_free(struct dst_entry * dst)
317 if (dst->obsolete > 1)
319 if (!atomic_read(&dst->__refcnt)) {
320 dst = dst_destroy(dst);
327 static inline void dst_rcu_free(struct rcu_head *head)
329 struct dst_entry *dst = container_of(head, struct dst_entry, rcu_head);
333 static inline void dst_confirm(struct dst_entry *dst)
336 neigh_confirm(dst->neighbour);
339 static inline void dst_link_failure(struct sk_buff *skb)
341 struct dst_entry *dst = skb_dst(skb);
342 if (dst && dst->ops && dst->ops->link_failure)
343 dst->ops->link_failure(skb);
346 static inline void dst_set_expires(struct dst_entry *dst, int timeout)
348 unsigned long expires = jiffies + timeout;
353 if (dst->expires == 0 || time_before(expires, dst->expires))
354 dst->expires = expires;
357 /* Output packet to network from transport. */
358 static inline int dst_output(struct sk_buff *skb)
360 return skb_dst(skb)->output(skb);
363 /* Input packet from network to transport. */
364 static inline int dst_input(struct sk_buff *skb)
366 return skb_dst(skb)->input(skb);
369 static inline struct dst_entry *dst_check(struct dst_entry *dst, u32 cookie)
372 dst = dst->ops->check(dst, cookie);
376 extern void dst_init(void);
378 /* Flags for xfrm_lookup flags argument. */
380 XFRM_LOOKUP_WAIT = 1 << 0,
381 XFRM_LOOKUP_ICMP = 1 << 1,
386 static inline int xfrm_lookup(struct net *net, struct dst_entry **dst_p,
387 struct flowi *fl, struct sock *sk, int flags)
391 static inline int __xfrm_lookup(struct net *net, struct dst_entry **dst_p,
392 struct flowi *fl, struct sock *sk, int flags)
397 extern int xfrm_lookup(struct net *net, struct dst_entry **dst_p,
398 struct flowi *fl, struct sock *sk, int flags);
399 extern int __xfrm_lookup(struct net *net, struct dst_entry **dst_p,
400 struct flowi *fl, struct sock *sk, int flags);
404 #endif /* _NET_DST_H */