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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
11#include <linux/config.h>
Arnaldo Carvalho de Melo14c85022005-12-27 02:43:12 -020012#include <linux/netdevice.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070013#include <linux/rtnetlink.h>
14#include <linux/rcupdate.h>
15#include <linux/jiffies.h>
16#include <net/neighbour.h>
17#include <asm/processor.h>
18
19/*
20 * 0 - no debugging messages
21 * 1 - rare events and bugs (default)
22 * 2 - trace mode.
23 */
24#define RT_CACHE_DEBUG 0
25
26#define DST_GC_MIN (HZ/10)
27#define DST_GC_INC (HZ/2)
28#define DST_GC_MAX (120*HZ)
29
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.
35 */
36
37struct sk_buff;
38
39struct dst_entry
40{
41 struct dst_entry *next;
42 atomic_t __refcnt; /* client references */
43 int __use;
44 struct dst_entry *child;
45 struct net_device *dev;
Herbert Xuc4d54112005-04-19 20:46:37 -070046 short error;
47 short obsolete;
Linus Torvalds1da177e2005-04-16 15:20:36 -070048 int flags;
49#define DST_HOST 1
50#define DST_NOXFRM 2
51#define DST_NOPOLICY 4
52#define DST_NOHASH 8
53#define DST_BALANCED 0x10
54 unsigned long lastuse;
55 unsigned long expires;
56
57 unsigned short header_len; /* more space at head required */
58 unsigned short trailer_len; /* space to reserve at tail */
59
60 u32 metrics[RTAX_MAX];
61 struct dst_entry *path;
62
63 unsigned long rate_last; /* rate limiting for ICMP */
64 unsigned long rate_tokens;
65
Linus Torvalds1da177e2005-04-16 15:20:36 -070066 struct neighbour *neighbour;
67 struct hh_cache *hh;
68 struct xfrm_state *xfrm;
69
70 int (*input)(struct sk_buff*);
71 int (*output)(struct sk_buff*);
72
73#ifdef CONFIG_NET_CLS_ROUTE
74 __u32 tclassid;
75#endif
76
77 struct dst_ops *ops;
78 struct rcu_head rcu_head;
79
80 char info[0];
81};
82
83
84struct dst_ops
85{
86 unsigned short family;
87 unsigned short protocol;
88 unsigned gc_thresh;
89
90 int (*gc)(void);
91 struct dst_entry * (*check)(struct dst_entry *, __u32 cookie);
92 void (*destroy)(struct dst_entry *);
93 void (*ifdown)(struct dst_entry *,
94 struct net_device *dev, int how);
95 struct dst_entry * (*negative_advice)(struct dst_entry *);
96 void (*link_failure)(struct sk_buff *);
97 void (*update_pmtu)(struct dst_entry *dst, u32 mtu);
Linus Torvalds1da177e2005-04-16 15:20:36 -070098 int entry_size;
99
100 atomic_t entries;
101 kmem_cache_t *kmem_cachep;
102};
103
104#ifdef __KERNEL__
105
106static inline u32
107dst_metric(const struct dst_entry *dst, int metric)
108{
109 return dst->metrics[metric-1];
110}
111
112static inline u32 dst_mtu(const struct dst_entry *dst)
113{
114 u32 mtu = dst_metric(dst, RTAX_MTU);
115 /*
116 * Alexey put it here, so ask him about it :)
117 */
118 barrier();
119 return mtu;
120}
121
122static inline u32
123dst_allfrag(const struct dst_entry *dst)
124{
125 int ret = dst_metric(dst, RTAX_FEATURES) & RTAX_FEATURE_ALLFRAG;
126 /* Yes, _exactly_. This is paranoia. */
127 barrier();
128 return ret;
129}
130
131static inline int
132dst_metric_locked(struct dst_entry *dst, int metric)
133{
134 return dst_metric(dst, RTAX_LOCK) & (1<<metric);
135}
136
137static inline void dst_hold(struct dst_entry * dst)
138{
139 atomic_inc(&dst->__refcnt);
140}
141
142static inline
143struct dst_entry * dst_clone(struct dst_entry * dst)
144{
145 if (dst)
146 atomic_inc(&dst->__refcnt);
147 return dst;
148}
149
150static inline
151void dst_release(struct dst_entry * dst)
152{
153 if (dst) {
154 WARN_ON(atomic_read(&dst->__refcnt) < 1);
155 smp_mb__before_atomic_dec();
156 atomic_dec(&dst->__refcnt);
157 }
158}
159
160/* Children define the path of the packet through the
161 * Linux networking. Thus, destinations are stackable.
162 */
163
164static inline struct dst_entry *dst_pop(struct dst_entry *dst)
165{
166 struct dst_entry *child = dst_clone(dst->child);
167
168 dst_release(dst);
169 return child;
170}
171
172extern void * dst_alloc(struct dst_ops * ops);
173extern void __dst_free(struct dst_entry * dst);
174extern struct dst_entry *dst_destroy(struct dst_entry * dst);
175
176static inline void dst_free(struct dst_entry * dst)
177{
178 if (dst->obsolete > 1)
179 return;
180 if (!atomic_read(&dst->__refcnt)) {
181 dst = dst_destroy(dst);
182 if (!dst)
183 return;
184 }
185 __dst_free(dst);
186}
187
188static inline void dst_rcu_free(struct rcu_head *head)
189{
190 struct dst_entry *dst = container_of(head, struct dst_entry, rcu_head);
191 dst_free(dst);
192}
193
194static inline void dst_confirm(struct dst_entry *dst)
195{
196 if (dst)
197 neigh_confirm(dst->neighbour);
198}
199
200static inline void dst_negative_advice(struct dst_entry **dst_p)
201{
202 struct dst_entry * dst = *dst_p;
203 if (dst && dst->ops->negative_advice)
204 *dst_p = dst->ops->negative_advice(dst);
205}
206
207static inline void dst_link_failure(struct sk_buff *skb)
208{
209 struct dst_entry * dst = skb->dst;
210 if (dst && dst->ops && dst->ops->link_failure)
211 dst->ops->link_failure(skb);
212}
213
214static inline void dst_set_expires(struct dst_entry *dst, int timeout)
215{
216 unsigned long expires = jiffies + timeout;
217
218 if (expires == 0)
219 expires = 1;
220
221 if (dst->expires == 0 || time_before(expires, dst->expires))
222 dst->expires = expires;
223}
224
225/* Output packet to network from transport. */
226static inline int dst_output(struct sk_buff *skb)
227{
Patrick McHardy16a66772006-01-06 23:01:48 -0800228 return skb->dst->output(skb);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700229}
230
231/* Input packet from network to transport. */
232static inline int dst_input(struct sk_buff *skb)
233{
234 int err;
235
236 for (;;) {
237 err = skb->dst->input(skb);
238
239 if (likely(err == 0))
240 return err;
241 /* Oh, Jamal... Seems, I will not forgive you this mess. :-) */
242 if (unlikely(err != NET_XMIT_BYPASS))
243 return err;
244 }
245}
246
247static inline struct dst_entry *dst_check(struct dst_entry *dst, u32 cookie)
248{
249 if (dst->obsolete)
250 dst = dst->ops->check(dst, cookie);
251 return dst;
252}
253
254extern void dst_init(void);
255
256struct flowi;
257#ifndef CONFIG_XFRM
258static inline int xfrm_lookup(struct dst_entry **dst_p, struct flowi *fl,
259 struct sock *sk, int flags)
260{
261 return 0;
262}
263#else
264extern int xfrm_lookup(struct dst_entry **dst_p, struct flowi *fl,
265 struct sock *sk, int flags);
266#endif
267#endif
268
269#endif /* _NET_DST_H */