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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
Linus Torvalds1da177e2005-04-16 15:20:36 -070050 unsigned long expires;
51
52 unsigned short header_len; /* more space at head required */
Masahide NAKAMURA1b5c2292006-08-23 18:11:50 -070053 unsigned short nfheader_len; /* more non-fragment space at head required */
Linus Torvalds1da177e2005-04-16 15:20:36 -070054 unsigned short trailer_len; /* space to reserve at tail */
55
56 u32 metrics[RTAX_MAX];
57 struct dst_entry *path;
58
59 unsigned long rate_last; /* rate limiting for ICMP */
60 unsigned long rate_tokens;
61
Linus Torvalds1da177e2005-04-16 15:20:36 -070062 struct neighbour *neighbour;
63 struct hh_cache *hh;
64 struct xfrm_state *xfrm;
65
66 int (*input)(struct sk_buff*);
67 int (*output)(struct sk_buff*);
68
69#ifdef CONFIG_NET_CLS_ROUTE
70 __u32 tclassid;
71#endif
72
73 struct dst_ops *ops;
Linus Torvalds1da177e2005-04-16 15:20:36 -070074
Eric Dumazet1e19e022007-02-09 16:26:55 -080075 unsigned long lastuse;
76 atomic_t __refcnt; /* client references */
77 int __use;
78 union {
79 struct dst_entry *next;
80 struct rtable *rt_next;
81 struct rt6_info *rt6_next;
82 struct dn_route *dn_next;
83 };
Linus Torvalds1da177e2005-04-16 15:20:36 -070084 char info[0];
85};
86
87
88struct dst_ops
89{
90 unsigned short family;
Al Virod77072e2006-09-28 14:20:34 -070091 __be16 protocol;
Linus Torvalds1da177e2005-04-16 15:20:36 -070092 unsigned gc_thresh;
93
94 int (*gc)(void);
95 struct dst_entry * (*check)(struct dst_entry *, __u32 cookie);
96 void (*destroy)(struct dst_entry *);
97 void (*ifdown)(struct dst_entry *,
98 struct net_device *dev, int how);
99 struct dst_entry * (*negative_advice)(struct dst_entry *);
100 void (*link_failure)(struct sk_buff *);
101 void (*update_pmtu)(struct dst_entry *dst, u32 mtu);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700102 int entry_size;
103
104 atomic_t entries;
Christoph Lametere18b8902006-12-06 20:33:20 -0800105 struct kmem_cache *kmem_cachep;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700106};
107
108#ifdef __KERNEL__
109
110static inline u32
111dst_metric(const struct dst_entry *dst, int metric)
112{
113 return dst->metrics[metric-1];
114}
115
116static inline u32 dst_mtu(const struct dst_entry *dst)
117{
118 u32 mtu = dst_metric(dst, RTAX_MTU);
119 /*
120 * Alexey put it here, so ask him about it :)
121 */
122 barrier();
123 return mtu;
124}
125
126static inline u32
127dst_allfrag(const struct dst_entry *dst)
128{
129 int ret = dst_metric(dst, RTAX_FEATURES) & RTAX_FEATURE_ALLFRAG;
130 /* Yes, _exactly_. This is paranoia. */
131 barrier();
132 return ret;
133}
134
135static inline int
136dst_metric_locked(struct dst_entry *dst, int metric)
137{
138 return dst_metric(dst, RTAX_LOCK) & (1<<metric);
139}
140
141static inline void dst_hold(struct dst_entry * dst)
142{
143 atomic_inc(&dst->__refcnt);
144}
145
146static inline
147struct dst_entry * dst_clone(struct dst_entry * dst)
148{
149 if (dst)
150 atomic_inc(&dst->__refcnt);
151 return dst;
152}
153
154static inline
155void dst_release(struct dst_entry * dst)
156{
157 if (dst) {
158 WARN_ON(atomic_read(&dst->__refcnt) < 1);
159 smp_mb__before_atomic_dec();
160 atomic_dec(&dst->__refcnt);
161 }
162}
163
164/* Children define the path of the packet through the
165 * Linux networking. Thus, destinations are stackable.
166 */
167
168static inline struct dst_entry *dst_pop(struct dst_entry *dst)
169{
170 struct dst_entry *child = dst_clone(dst->child);
171
172 dst_release(dst);
173 return child;
174}
175
176extern void * dst_alloc(struct dst_ops * ops);
177extern void __dst_free(struct dst_entry * dst);
178extern struct dst_entry *dst_destroy(struct dst_entry * dst);
179
180static inline void dst_free(struct dst_entry * dst)
181{
182 if (dst->obsolete > 1)
183 return;
184 if (!atomic_read(&dst->__refcnt)) {
185 dst = dst_destroy(dst);
186 if (!dst)
187 return;
188 }
189 __dst_free(dst);
190}
191
192static inline void dst_rcu_free(struct rcu_head *head)
193{
194 struct dst_entry *dst = container_of(head, struct dst_entry, rcu_head);
195 dst_free(dst);
196}
197
198static inline void dst_confirm(struct dst_entry *dst)
199{
200 if (dst)
201 neigh_confirm(dst->neighbour);
202}
203
204static inline void dst_negative_advice(struct dst_entry **dst_p)
205{
206 struct dst_entry * dst = *dst_p;
207 if (dst && dst->ops->negative_advice)
208 *dst_p = dst->ops->negative_advice(dst);
209}
210
211static inline void dst_link_failure(struct sk_buff *skb)
212{
213 struct dst_entry * dst = skb->dst;
214 if (dst && dst->ops && dst->ops->link_failure)
215 dst->ops->link_failure(skb);
216}
217
218static inline void dst_set_expires(struct dst_entry *dst, int timeout)
219{
220 unsigned long expires = jiffies + timeout;
221
222 if (expires == 0)
223 expires = 1;
224
225 if (dst->expires == 0 || time_before(expires, dst->expires))
226 dst->expires = expires;
227}
228
229/* Output packet to network from transport. */
230static inline int dst_output(struct sk_buff *skb)
231{
Patrick McHardy16a66772006-01-06 23:01:48 -0800232 return skb->dst->output(skb);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700233}
234
235/* Input packet from network to transport. */
236static inline int dst_input(struct sk_buff *skb)
237{
238 int err;
239
240 for (;;) {
241 err = skb->dst->input(skb);
242
243 if (likely(err == 0))
244 return err;
245 /* Oh, Jamal... Seems, I will not forgive you this mess. :-) */
246 if (unlikely(err != NET_XMIT_BYPASS))
247 return err;
248 }
249}
250
251static inline struct dst_entry *dst_check(struct dst_entry *dst, u32 cookie)
252{
253 if (dst->obsolete)
254 dst = dst->ops->check(dst, cookie);
255 return dst;
256}
257
258extern void dst_init(void);
259
260struct flowi;
261#ifndef CONFIG_XFRM
262static inline int xfrm_lookup(struct dst_entry **dst_p, struct flowi *fl,
263 struct sock *sk, int flags)
264{
265 return 0;
266}
David S. Miller14e50e52007-05-24 18:17:54 -0700267static inline int __xfrm_lookup(struct dst_entry **dst_p, struct flowi *fl,
268 struct sock *sk, int flags)
269{
270 return 0;
271}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700272#else
273extern int xfrm_lookup(struct dst_entry **dst_p, struct flowi *fl,
274 struct sock *sk, int flags);
David S. Miller14e50e52007-05-24 18:17:54 -0700275extern int __xfrm_lookup(struct dst_entry **dst_p, struct flowi *fl,
276 struct sock *sk, int flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700277#endif
278#endif
279
280#endif /* _NET_DST_H */