2 * net/dst.h Protocol independent destination cache definitions.
4 * Authors: Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
11 #include <linux/netdevice.h>
12 #include <linux/rtnetlink.h>
13 #include <linux/rcupdate.h>
14 #include <linux/jiffies.h>
15 #include <net/neighbour.h>
16 #include <asm/processor.h>
19 * 0 - no debugging messages
20 * 1 - rare events and bugs (default)
23 #define RT_CACHE_DEBUG 0
25 #define DST_GC_MIN (HZ/10)
26 #define DST_GC_INC (HZ/2)
27 #define DST_GC_MAX (120*HZ)
29 /* Each dst_entry has reference count and sits in some parent list(s).
30 * When it is removed from parent list, it is "freed" (dst_free).
31 * After this it enters dead state (dst->obsolete > 0) and if its refcnt
32 * is zero, it can be destroyed immediately, otherwise it is added
33 * 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;
48 #define DST_NOPOLICY 4
50 unsigned long expires;
52 unsigned short header_len; /* more space at head required */
53 unsigned short trailer_len; /* space to reserve at tail */
55 u32 metrics[RTAX_MAX];
56 struct dst_entry *path;
58 unsigned long rate_last; /* rate limiting for ICMP */
59 unsigned long rate_tokens;
61 struct neighbour *neighbour;
63 struct xfrm_state *xfrm;
65 int (*input)(struct sk_buff*);
66 int (*output)(struct sk_buff*);
68 #ifdef CONFIG_NET_CLS_ROUTE
74 unsigned long lastuse;
75 atomic_t __refcnt; /* client references */
78 struct dst_entry *next;
79 struct rtable *rt_next;
80 struct rt6_info *rt6_next;
81 struct dn_route *dn_next;
89 unsigned short family;
94 struct dst_entry * (*check)(struct dst_entry *, __u32 cookie);
95 void (*destroy)(struct dst_entry *);
96 void (*ifdown)(struct dst_entry *,
97 struct net_device *dev, int how);
98 struct dst_entry * (*negative_advice)(struct dst_entry *);
99 void (*link_failure)(struct sk_buff *);
100 void (*update_pmtu)(struct dst_entry *dst, u32 mtu);
104 struct kmem_cache *kmem_cachep;
110 dst_metric(const struct dst_entry *dst, int metric)
112 return dst->metrics[metric-1];
115 static inline u32 dst_mtu(const struct dst_entry *dst)
117 u32 mtu = dst_metric(dst, RTAX_MTU);
119 * Alexey put it here, so ask him about it :)
126 dst_allfrag(const struct dst_entry *dst)
128 int ret = dst_metric(dst, RTAX_FEATURES) & RTAX_FEATURE_ALLFRAG;
129 /* Yes, _exactly_. This is paranoia. */
135 dst_metric_locked(struct dst_entry *dst, int metric)
137 return dst_metric(dst, RTAX_LOCK) & (1<<metric);
140 static inline void dst_hold(struct dst_entry * dst)
142 atomic_inc(&dst->__refcnt);
145 static inline void dst_use(struct dst_entry *dst, unsigned long time)
153 struct dst_entry * dst_clone(struct dst_entry * dst)
156 atomic_inc(&dst->__refcnt);
161 void dst_release(struct dst_entry * dst)
164 WARN_ON(atomic_read(&dst->__refcnt) < 1);
165 smp_mb__before_atomic_dec();
166 atomic_dec(&dst->__refcnt);
170 /* Children define the path of the packet through the
171 * Linux networking. Thus, destinations are stackable.
174 static inline struct dst_entry *dst_pop(struct dst_entry *dst)
176 struct dst_entry *child = dst_clone(dst->child);
182 extern void * dst_alloc(struct dst_ops * ops);
183 extern void __dst_free(struct dst_entry * dst);
184 extern struct dst_entry *dst_destroy(struct dst_entry * dst);
186 static inline void dst_free(struct dst_entry * dst)
188 if (dst->obsolete > 1)
190 if (!atomic_read(&dst->__refcnt)) {
191 dst = dst_destroy(dst);
198 static inline void dst_rcu_free(struct rcu_head *head)
200 struct dst_entry *dst = container_of(head, struct dst_entry, rcu_head);
204 static inline void dst_confirm(struct dst_entry *dst)
207 neigh_confirm(dst->neighbour);
210 static inline void dst_negative_advice(struct dst_entry **dst_p)
212 struct dst_entry * dst = *dst_p;
213 if (dst && dst->ops->negative_advice)
214 *dst_p = dst->ops->negative_advice(dst);
217 static inline void dst_link_failure(struct sk_buff *skb)
219 struct dst_entry * dst = skb->dst;
220 if (dst && dst->ops && dst->ops->link_failure)
221 dst->ops->link_failure(skb);
224 static inline void dst_set_expires(struct dst_entry *dst, int timeout)
226 unsigned long expires = jiffies + timeout;
231 if (dst->expires == 0 || time_before(expires, dst->expires))
232 dst->expires = expires;
235 /* Output packet to network from transport. */
236 static inline int dst_output(struct sk_buff *skb)
238 return skb->dst->output(skb);
241 /* Input packet from network to transport. */
242 static inline int dst_input(struct sk_buff *skb)
247 err = skb->dst->input(skb);
249 if (likely(err == 0))
251 /* Oh, Jamal... Seems, I will not forgive you this mess. :-) */
252 if (unlikely(err != NET_XMIT_BYPASS))
257 static inline struct dst_entry *dst_check(struct dst_entry *dst, u32 cookie)
260 dst = dst->ops->check(dst, cookie);
264 extern void dst_init(void);
268 static inline int xfrm_lookup(struct dst_entry **dst_p, struct flowi *fl,
269 struct sock *sk, int flags)
273 static inline int __xfrm_lookup(struct dst_entry **dst_p, struct flowi *fl,
274 struct sock *sk, int flags)
279 extern int xfrm_lookup(struct dst_entry **dst_p, struct flowi *fl,
280 struct sock *sk, int flags);
281 extern int __xfrm_lookup(struct dst_entry **dst_p, struct flowi *fl,
282 struct sock *sk, int flags);
286 #endif /* _NET_DST_H */