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Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
2 * net/dst.h Protocol independent destination cache definitions.
3 *
4 * Authors: Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
5 *
6 */
7
8#ifndef _NET_DST_H
9#define _NET_DST_H
10
Arnaldo Carvalho de Melo14c85022005-12-27 02:43:12 -020011#include <linux/netdevice.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070012#include <linux/rtnetlink.h>
13#include <linux/rcupdate.h>
14#include <linux/jiffies.h>
15#include <net/neighbour.h>
16#include <asm/processor.h>
17
18/*
19 * 0 - no debugging messages
20 * 1 - rare events and bugs (default)
21 * 2 - trace mode.
22 */
23#define RT_CACHE_DEBUG 0
24
25#define DST_GC_MIN (HZ/10)
26#define DST_GC_INC (HZ/2)
27#define DST_GC_MAX (120*HZ)
28
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.
34 */
35
36struct sk_buff;
37
38struct dst_entry
39{
Eric Dumazet1e19e022007-02-09 16:26:55 -080040 struct rcu_head rcu_head;
Linus Torvalds1da177e2005-04-16 15:20:36 -070041 struct dst_entry *child;
42 struct net_device *dev;
Herbert Xuc4d54112005-04-19 20:46:37 -070043 short error;
44 short obsolete;
Linus Torvalds1da177e2005-04-16 15:20:36 -070045 int flags;
46#define DST_HOST 1
47#define DST_NOXFRM 2
48#define DST_NOPOLICY 4
49#define DST_NOHASH 8
50#define DST_BALANCED 0x10
Linus Torvalds1da177e2005-04-16 15:20:36 -070051 unsigned long expires;
52
53 unsigned short header_len; /* more space at head required */
Masahide NAKAMURA1b5c2292006-08-23 18:11:50 -070054 unsigned short nfheader_len; /* more non-fragment space at head required */
Linus Torvalds1da177e2005-04-16 15:20:36 -070055 unsigned short trailer_len; /* space to reserve at tail */
56
57 u32 metrics[RTAX_MAX];
58 struct dst_entry *path;
59
60 unsigned long rate_last; /* rate limiting for ICMP */
61 unsigned long rate_tokens;
62
Linus Torvalds1da177e2005-04-16 15:20:36 -070063 struct neighbour *neighbour;
64 struct hh_cache *hh;
65 struct xfrm_state *xfrm;
66
67 int (*input)(struct sk_buff*);
68 int (*output)(struct sk_buff*);
69
70#ifdef CONFIG_NET_CLS_ROUTE
71 __u32 tclassid;
72#endif
73
74 struct dst_ops *ops;
Linus Torvalds1da177e2005-04-16 15:20:36 -070075
Eric Dumazet1e19e022007-02-09 16:26:55 -080076 unsigned long lastuse;
77 atomic_t __refcnt; /* client references */
78 int __use;
79 union {
80 struct dst_entry *next;
81 struct rtable *rt_next;
82 struct rt6_info *rt6_next;
83 struct dn_route *dn_next;
84 };
Linus Torvalds1da177e2005-04-16 15:20:36 -070085 char info[0];
86};
87
88
89struct dst_ops
90{
91 unsigned short family;
Al Virod77072e2006-09-28 14:20:34 -070092 __be16 protocol;
Linus Torvalds1da177e2005-04-16 15:20:36 -070093 unsigned gc_thresh;
94
95 int (*gc)(void);
96 struct dst_entry * (*check)(struct dst_entry *, __u32 cookie);
97 void (*destroy)(struct dst_entry *);
98 void (*ifdown)(struct dst_entry *,
99 struct net_device *dev, int how);
100 struct dst_entry * (*negative_advice)(struct dst_entry *);
101 void (*link_failure)(struct sk_buff *);
102 void (*update_pmtu)(struct dst_entry *dst, u32 mtu);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700103 int entry_size;
104
105 atomic_t entries;
Christoph Lametere18b8902006-12-06 20:33:20 -0800106 struct kmem_cache *kmem_cachep;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700107};
108
109#ifdef __KERNEL__
110
111static inline u32
112dst_metric(const struct dst_entry *dst, int metric)
113{
114 return dst->metrics[metric-1];
115}
116
117static inline u32 dst_mtu(const struct dst_entry *dst)
118{
119 u32 mtu = dst_metric(dst, RTAX_MTU);
120 /*
121 * Alexey put it here, so ask him about it :)
122 */
123 barrier();
124 return mtu;
125}
126
127static inline u32
128dst_allfrag(const struct dst_entry *dst)
129{
130 int ret = dst_metric(dst, RTAX_FEATURES) & RTAX_FEATURE_ALLFRAG;
131 /* Yes, _exactly_. This is paranoia. */
132 barrier();
133 return ret;
134}
135
136static inline int
137dst_metric_locked(struct dst_entry *dst, int metric)
138{
139 return dst_metric(dst, RTAX_LOCK) & (1<<metric);
140}
141
142static inline void dst_hold(struct dst_entry * dst)
143{
144 atomic_inc(&dst->__refcnt);
145}
146
147static inline
148struct dst_entry * dst_clone(struct dst_entry * dst)
149{
150 if (dst)
151 atomic_inc(&dst->__refcnt);
152 return dst;
153}
154
155static inline
156void dst_release(struct dst_entry * dst)
157{
158 if (dst) {
159 WARN_ON(atomic_read(&dst->__refcnt) < 1);
160 smp_mb__before_atomic_dec();
161 atomic_dec(&dst->__refcnt);
162 }
163}
164
165/* Children define the path of the packet through the
166 * Linux networking. Thus, destinations are stackable.
167 */
168
169static inline struct dst_entry *dst_pop(struct dst_entry *dst)
170{
171 struct dst_entry *child = dst_clone(dst->child);
172
173 dst_release(dst);
174 return child;
175}
176
177extern void * dst_alloc(struct dst_ops * ops);
178extern void __dst_free(struct dst_entry * dst);
179extern struct dst_entry *dst_destroy(struct dst_entry * dst);
180
181static inline void dst_free(struct dst_entry * dst)
182{
183 if (dst->obsolete > 1)
184 return;
185 if (!atomic_read(&dst->__refcnt)) {
186 dst = dst_destroy(dst);
187 if (!dst)
188 return;
189 }
190 __dst_free(dst);
191}
192
193static inline void dst_rcu_free(struct rcu_head *head)
194{
195 struct dst_entry *dst = container_of(head, struct dst_entry, rcu_head);
196 dst_free(dst);
197}
198
199static inline void dst_confirm(struct dst_entry *dst)
200{
201 if (dst)
202 neigh_confirm(dst->neighbour);
203}
204
205static inline void dst_negative_advice(struct dst_entry **dst_p)
206{
207 struct dst_entry * dst = *dst_p;
208 if (dst && dst->ops->negative_advice)
209 *dst_p = dst->ops->negative_advice(dst);
210}
211
212static inline void dst_link_failure(struct sk_buff *skb)
213{
214 struct dst_entry * dst = skb->dst;
215 if (dst && dst->ops && dst->ops->link_failure)
216 dst->ops->link_failure(skb);
217}
218
219static inline void dst_set_expires(struct dst_entry *dst, int timeout)
220{
221 unsigned long expires = jiffies + timeout;
222
223 if (expires == 0)
224 expires = 1;
225
226 if (dst->expires == 0 || time_before(expires, dst->expires))
227 dst->expires = expires;
228}
229
230/* Output packet to network from transport. */
231static inline int dst_output(struct sk_buff *skb)
232{
Patrick McHardy16a66772006-01-06 23:01:48 -0800233 return skb->dst->output(skb);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700234}
235
236/* Input packet from network to transport. */
237static inline int dst_input(struct sk_buff *skb)
238{
239 int err;
240
241 for (;;) {
242 err = skb->dst->input(skb);
243
244 if (likely(err == 0))
245 return err;
246 /* Oh, Jamal... Seems, I will not forgive you this mess. :-) */
247 if (unlikely(err != NET_XMIT_BYPASS))
248 return err;
249 }
250}
251
252static inline struct dst_entry *dst_check(struct dst_entry *dst, u32 cookie)
253{
254 if (dst->obsolete)
255 dst = dst->ops->check(dst, cookie);
256 return dst;
257}
258
259extern void dst_init(void);
260
261struct flowi;
262#ifndef CONFIG_XFRM
263static inline int xfrm_lookup(struct dst_entry **dst_p, struct flowi *fl,
264 struct sock *sk, int flags)
265{
266 return 0;
267}
David S. Miller14e50e52007-05-24 18:17:54 -0700268static inline int __xfrm_lookup(struct dst_entry **dst_p, struct flowi *fl,
269 struct sock *sk, int flags)
270{
271 return 0;
272}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700273#else
274extern int xfrm_lookup(struct dst_entry **dst_p, struct flowi *fl,
275 struct sock *sk, int flags);
David S. Miller14e50e52007-05-24 18:17:54 -0700276extern int __xfrm_lookup(struct dst_entry **dst_p, struct flowi *fl,
277 struct sock *sk, int flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700278#endif
279#endif
280
281#endif /* _NET_DST_H */