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 unsigned int rate_tokens;
56 unsigned long rate_last; /* rate limiting for ICMP */
58 struct dst_entry *path;
60 struct neighbour *neighbour;
63 struct xfrm_state *xfrm;
65 int (*input)(struct sk_buff*);
66 int (*output)(struct sk_buff*);
70 u32 metrics[RTAX_MAX];
72 #ifdef CONFIG_NET_CLS_ROUTE
77 * __refcnt wants to be on a different cache line from
78 * input/output/ops or performance tanks badly
80 atomic_t __refcnt; /* client references */
82 unsigned long lastuse;
84 struct dst_entry *next;
85 struct rtable *rt_next;
86 struct rt6_info *rt6_next;
87 struct dn_route *dn_next;
94 unsigned short family;
98 int (*gc)(struct dst_ops *ops);
99 struct dst_entry * (*check)(struct dst_entry *, __u32 cookie);
100 void (*destroy)(struct dst_entry *);
101 void (*ifdown)(struct dst_entry *,
102 struct net_device *dev, int how);
103 struct dst_entry * (*negative_advice)(struct dst_entry *);
104 void (*link_failure)(struct sk_buff *);
105 void (*update_pmtu)(struct dst_entry *dst, u32 mtu);
106 int (*local_out)(struct sk_buff *skb);
110 struct kmem_cache *kmem_cachep;
117 dst_metric(const struct dst_entry *dst, int metric)
119 return dst->metrics[metric-1];
122 static inline u32 dst_mtu(const struct dst_entry *dst)
124 u32 mtu = dst_metric(dst, RTAX_MTU);
126 * Alexey put it here, so ask him about it :)
132 /* RTT metrics are stored in milliseconds for user ABI, but used as jiffies */
133 static inline unsigned long dst_metric_rtt(const struct dst_entry *dst, int metric)
135 return msecs_to_jiffies(dst_metric(dst, metric));
138 static inline void set_dst_metric_rtt(struct dst_entry *dst, int metric,
141 dst->metrics[metric-1] = jiffies_to_msecs(rtt);
145 dst_allfrag(const struct dst_entry *dst)
147 int ret = dst_metric(dst, RTAX_FEATURES) & RTAX_FEATURE_ALLFRAG;
148 /* Yes, _exactly_. This is paranoia. */
154 dst_metric_locked(struct dst_entry *dst, int metric)
156 return dst_metric(dst, RTAX_LOCK) & (1<<metric);
159 static inline void dst_hold(struct dst_entry * dst)
161 atomic_inc(&dst->__refcnt);
164 static inline void dst_use(struct dst_entry *dst, unsigned long time)
172 struct dst_entry * dst_clone(struct dst_entry * dst)
175 atomic_inc(&dst->__refcnt);
179 extern void dst_release(struct dst_entry *dst);
181 /* Children define the path of the packet through the
182 * Linux networking. Thus, destinations are stackable.
185 static inline struct dst_entry *dst_pop(struct dst_entry *dst)
187 struct dst_entry *child = dst_clone(dst->child);
193 extern int dst_discard(struct sk_buff *skb);
194 extern void * dst_alloc(struct dst_ops * ops);
195 extern void __dst_free(struct dst_entry * dst);
196 extern struct dst_entry *dst_destroy(struct dst_entry * dst);
198 static inline void dst_free(struct dst_entry * dst)
200 if (dst->obsolete > 1)
202 if (!atomic_read(&dst->__refcnt)) {
203 dst = dst_destroy(dst);
210 static inline void dst_rcu_free(struct rcu_head *head)
212 struct dst_entry *dst = container_of(head, struct dst_entry, rcu_head);
216 static inline void dst_confirm(struct dst_entry *dst)
219 neigh_confirm(dst->neighbour);
222 static inline void dst_negative_advice(struct dst_entry **dst_p)
224 struct dst_entry * dst = *dst_p;
225 if (dst && dst->ops->negative_advice)
226 *dst_p = dst->ops->negative_advice(dst);
229 static inline void dst_link_failure(struct sk_buff *skb)
231 struct dst_entry * dst = skb->dst;
232 if (dst && dst->ops && dst->ops->link_failure)
233 dst->ops->link_failure(skb);
236 static inline void dst_set_expires(struct dst_entry *dst, int timeout)
238 unsigned long expires = jiffies + timeout;
243 if (dst->expires == 0 || time_before(expires, dst->expires))
244 dst->expires = expires;
247 /* Output packet to network from transport. */
248 static inline int dst_output(struct sk_buff *skb)
250 return skb->dst->output(skb);
253 /* Input packet from network to transport. */
254 static inline int dst_input(struct sk_buff *skb)
256 return skb->dst->input(skb);
259 static inline struct dst_entry *dst_check(struct dst_entry *dst, u32 cookie)
262 dst = dst->ops->check(dst, cookie);
266 extern void dst_init(void);
268 /* Flags for xfrm_lookup flags argument. */
270 XFRM_LOOKUP_WAIT = 1 << 0,
271 XFRM_LOOKUP_ICMP = 1 << 1,
276 static inline int xfrm_lookup(struct dst_entry **dst_p, struct flowi *fl,
277 struct sock *sk, int flags)
281 static inline int __xfrm_lookup(struct dst_entry **dst_p, struct flowi *fl,
282 struct sock *sk, int flags)
287 extern int xfrm_lookup(struct dst_entry **dst_p, struct flowi *fl,
288 struct sock *sk, int flags);
289 extern int __xfrm_lookup(struct dst_entry **dst_p, struct flowi *fl,
290 struct sock *sk, int flags);
294 #endif /* _NET_DST_H */