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Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
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linux
1/*
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/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>
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{
40 struct rcu_head rcu_head;
41 struct dst_entry *child;
42 struct net_device *dev;
43 short error;
44 short obsolete;
45 int flags;
46#define DST_HOST 1
47#define DST_NOXFRM 2
48#define DST_NOPOLICY 4
49#define DST_NOHASH 8
50 unsigned long expires;
51
52 unsigned short header_len; /* more space at head required */
53 unsigned short trailer_len; /* space to reserve at tail */
54
55 unsigned int rate_tokens;
56 unsigned long rate_last; /* rate limiting for ICMP */
57
58 struct dst_entry *path;
59
60 struct neighbour *neighbour;
61 struct hh_cache *hh;
62#ifdef CONFIG_XFRM
63 struct xfrm_state *xfrm;
64#else
65 void *__pad1;
66#endif
67 int (*input)(struct sk_buff*);
68 int (*output)(struct sk_buff*);
69
70 struct dst_ops *ops;
71
72 u32 metrics[RTAX_MAX];
73
74#ifdef CONFIG_NET_CLS_ROUTE
75 __u32 tclassid;
76#else
77 __u32 __pad2;
78#endif
79
80
81 /*
82 * Align __refcnt to a 64 bytes alignment
83 * (L1_CACHE_SIZE would be too much)
84 */
85#ifdef CONFIG_64BIT
86 long __pad_to_align_refcnt[2];
87#else
88 long __pad_to_align_refcnt[1];
89#endif
90 /*
91 * __refcnt wants to be on a different cache line from
92 * input/output/ops or performance tanks badly
93 */
94 atomic_t __refcnt; /* client references */
95 int __use;
96 unsigned long lastuse;
97 union {
98 struct dst_entry *next;
99 struct rtable *rt_next;
100 struct rt6_info *rt6_next;
101 struct dn_route *dn_next;
102 };
103};
104
105
106struct dst_ops
107{
108 unsigned short family;
109 __be16 protocol;
110 unsigned gc_thresh;
111
112 int (*gc)(struct dst_ops *ops);
113 struct dst_entry * (*check)(struct dst_entry *, __u32 cookie);
114 void (*destroy)(struct dst_entry *);
115 void (*ifdown)(struct dst_entry *,
116 struct net_device *dev, int how);
117 struct dst_entry * (*negative_advice)(struct dst_entry *);
118 void (*link_failure)(struct sk_buff *);
119 void (*update_pmtu)(struct dst_entry *dst, u32 mtu);
120 int (*local_out)(struct sk_buff *skb);
121
122 atomic_t entries;
123 struct kmem_cache *kmem_cachep;
124 struct net *dst_net;
125};
126
127#ifdef __KERNEL__
128
129static inline u32
130dst_metric(const struct dst_entry *dst, int metric)
131{
132 return dst->metrics[metric-1];
133}
134
135static inline u32 dst_mtu(const struct dst_entry *dst)
136{
137 u32 mtu = dst_metric(dst, RTAX_MTU);
138 /*
139 * Alexey put it here, so ask him about it :)
140 */
141 barrier();
142 return mtu;
143}
144
145/* RTT metrics are stored in milliseconds for user ABI, but used as jiffies */
146static inline unsigned long dst_metric_rtt(const struct dst_entry *dst, int metric)
147{
148 return msecs_to_jiffies(dst_metric(dst, metric));
149}
150
151static inline void set_dst_metric_rtt(struct dst_entry *dst, int metric,
152 unsigned long rtt)
153{
154 dst->metrics[metric-1] = jiffies_to_msecs(rtt);
155}
156
157static inline u32
158dst_allfrag(const struct dst_entry *dst)
159{
160 int ret = dst_metric(dst, RTAX_FEATURES) & RTAX_FEATURE_ALLFRAG;
161 /* Yes, _exactly_. This is paranoia. */
162 barrier();
163 return ret;
164}
165
166static inline int
167dst_metric_locked(struct dst_entry *dst, int metric)
168{
169 return dst_metric(dst, RTAX_LOCK) & (1<<metric);
170}
171
172static inline void dst_hold(struct dst_entry * dst)
173{
174 /*
175 * If your kernel compilation stops here, please check
176 * __pad_to_align_refcnt declaration in struct dst_entry
177 */
178 BUILD_BUG_ON(offsetof(struct dst_entry, __refcnt) & 63);
179 atomic_inc(&dst->__refcnt);
180}
181
182static inline void dst_use(struct dst_entry *dst, unsigned long time)
183{
184 dst_hold(dst);
185 dst->__use++;
186 dst->lastuse = time;
187}
188
189static inline
190struct dst_entry * dst_clone(struct dst_entry * dst)
191{
192 if (dst)
193 atomic_inc(&dst->__refcnt);
194 return dst;
195}
196
197extern void dst_release(struct dst_entry *dst);
198
199/* Children define the path of the packet through the
200 * Linux networking. Thus, destinations are stackable.
201 */
202
203static inline struct dst_entry *dst_pop(struct dst_entry *dst)
204{
205 struct dst_entry *child = dst_clone(dst->child);
206
207 dst_release(dst);
208 return child;
209}
210
211extern int dst_discard(struct sk_buff *skb);
212extern void * dst_alloc(struct dst_ops * ops);
213extern void __dst_free(struct dst_entry * dst);
214extern struct dst_entry *dst_destroy(struct dst_entry * dst);
215
216static inline void dst_free(struct dst_entry * dst)
217{
218 if (dst->obsolete > 1)
219 return;
220 if (!atomic_read(&dst->__refcnt)) {
221 dst = dst_destroy(dst);
222 if (!dst)
223 return;
224 }
225 __dst_free(dst);
226}
227
228static inline void dst_rcu_free(struct rcu_head *head)
229{
230 struct dst_entry *dst = container_of(head, struct dst_entry, rcu_head);
231 dst_free(dst);
232}
233
234static inline void dst_confirm(struct dst_entry *dst)
235{
236 if (dst)
237 neigh_confirm(dst->neighbour);
238}
239
240static inline void dst_negative_advice(struct dst_entry **dst_p)
241{
242 struct dst_entry * dst = *dst_p;
243 if (dst && dst->ops->negative_advice)
244 *dst_p = dst->ops->negative_advice(dst);
245}
246
247static inline void dst_link_failure(struct sk_buff *skb)
248{
249 struct dst_entry * dst = skb->dst;
250 if (dst && dst->ops && dst->ops->link_failure)
251 dst->ops->link_failure(skb);
252}
253
254static inline void dst_set_expires(struct dst_entry *dst, int timeout)
255{
256 unsigned long expires = jiffies + timeout;
257
258 if (expires == 0)
259 expires = 1;
260
261 if (dst->expires == 0 || time_before(expires, dst->expires))
262 dst->expires = expires;
263}
264
265/* Output packet to network from transport. */
266static inline int dst_output(struct sk_buff *skb)
267{
268 return skb->dst->output(skb);
269}
270
271/* Input packet from network to transport. */
272static inline int dst_input(struct sk_buff *skb)
273{
274 return skb->dst->input(skb);
275}
276
277static inline struct dst_entry *dst_check(struct dst_entry *dst, u32 cookie)
278{
279 if (dst->obsolete)
280 dst = dst->ops->check(dst, cookie);
281 return dst;
282}
283
284extern void dst_init(void);
285
286/* Flags for xfrm_lookup flags argument. */
287enum {
288 XFRM_LOOKUP_WAIT = 1 << 0,
289 XFRM_LOOKUP_ICMP = 1 << 1,
290};
291
292struct flowi;
293#ifndef CONFIG_XFRM
294static inline int xfrm_lookup(struct net *net, struct dst_entry **dst_p,
295 struct flowi *fl, struct sock *sk, int flags)
296{
297 return 0;
298}
299static inline int __xfrm_lookup(struct net *net, struct dst_entry **dst_p,
300 struct flowi *fl, struct sock *sk, int flags)
301{
302 return 0;
303}
304#else
305extern int xfrm_lookup(struct net *net, struct dst_entry **dst_p,
306 struct flowi *fl, struct sock *sk, int flags);
307extern int __xfrm_lookup(struct net *net, struct dst_entry **dst_p,
308 struct flowi *fl, struct sock *sk, int flags);
309#endif
310#endif
311
312#endif /* _NET_DST_H */