net: change ip_default_ttl documentation
[deliverable/linux.git] / include / net / dst.h
CommitLineData
1da177e4
LT
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
86393e52 11#include <net/dst_ops.h>
14c85021 12#include <linux/netdevice.h>
1da177e4
LT
13#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
fd2c3ef7 39struct dst_entry {
1e19e02c 40 struct rcu_head rcu_head;
1da177e4
LT
41 struct dst_entry *child;
42 struct net_device *dev;
c4d54110
HX
43 short error;
44 short obsolete;
1da177e4 45 int flags;
c7d4426a
ED
46#define DST_HOST 0x0001
47#define DST_NOXFRM 0x0002
48#define DST_NOPOLICY 0x0004
49#define DST_NOHASH 0x0008
50#define DST_NOCACHE 0x0010
1da177e4
LT
51 unsigned long expires;
52
53 unsigned short header_len; /* more space at head required */
54 unsigned short trailer_len; /* space to reserve at tail */
55
69a73829 56 unsigned int rate_tokens;
f1dd9c37 57 unsigned long rate_last; /* rate limiting for ICMP */
69a73829 58
f1dd9c37 59 struct dst_entry *path;
1da177e4 60
1da177e4
LT
61 struct neighbour *neighbour;
62 struct hh_cache *hh;
def8b4fa 63#ifdef CONFIG_XFRM
1da177e4 64 struct xfrm_state *xfrm;
5635c10d
ED
65#else
66 void *__pad1;
def8b4fa 67#endif
1da177e4
LT
68 int (*input)(struct sk_buff*);
69 int (*output)(struct sk_buff*);
70
1da177e4 71 struct dst_ops *ops;
f1dd9c37 72
defb3519 73 u32 _metrics[RTAX_MAX];
f1dd9c37
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74
75#ifdef CONFIG_NET_CLS_ROUTE
76 __u32 tclassid;
5635c10d
ED
77#else
78 __u32 __pad2;
f1dd9c37
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79#endif
80
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ED
81
82 /*
83 * Align __refcnt to a 64 bytes alignment
84 * (L1_CACHE_SIZE would be too much)
85 */
86#ifdef CONFIG_64BIT
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ED
87 long __pad_to_align_refcnt[1];
88#endif
f1dd9c37
ZY
89 /*
90 * __refcnt wants to be on a different cache line from
91 * input/output/ops or performance tanks badly
92 */
1e19e02c
ED
93 atomic_t __refcnt; /* client references */
94 int __use;
f1dd9c37 95 unsigned long lastuse;
1e19e02c 96 union {
fc766e4c
ED
97 struct dst_entry *next;
98 struct rtable __rcu *rt_next;
99 struct rt6_info *rt6_next;
100 struct dn_route __rcu *dn_next;
1e19e02c 101 };
1da177e4
LT
102};
103
1da177e4
LT
104#ifdef __KERNEL__
105
106static inline u32
5170ae82 107dst_metric_raw(const struct dst_entry *dst, const int metric)
1da177e4 108{
defb3519
DM
109 return dst->_metrics[metric-1];
110}
111
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DM
112static inline u32
113dst_metric(const struct dst_entry *dst, const int metric)
114{
115 WARN_ON_ONCE(metric == RTAX_HOPLIMIT);
116 return dst_metric_raw(dst, metric);
117}
118
defb3519
DM
119static inline void dst_metric_set(struct dst_entry *dst, int metric, u32 val)
120{
121 dst->_metrics[metric-1] = val;
122}
123
124static inline void dst_import_metrics(struct dst_entry *dst, const u32 *src_metrics)
125{
126 memcpy(dst->_metrics, src_metrics, RTAX_MAX * sizeof(u32));
127}
128
129static inline void dst_copy_metrics(struct dst_entry *dest, const struct dst_entry *src)
130{
131 dst_import_metrics(dest, src->_metrics);
132}
133
134static inline u32 *dst_metrics_ptr(struct dst_entry *dst)
135{
136 return dst->_metrics;
1da177e4
LT
137}
138
0c3adfb8
GBY
139static inline u32
140dst_feature(const struct dst_entry *dst, u32 feature)
141{
bb5b7c11 142 return dst_metric(dst, RTAX_FEATURES) & feature;
0c3adfb8
GBY
143}
144
1da177e4
LT
145static inline u32 dst_mtu(const struct dst_entry *dst)
146{
147 u32 mtu = dst_metric(dst, RTAX_MTU);
148 /*
149 * Alexey put it here, so ask him about it :)
150 */
151 barrier();
152 return mtu;
153}
154
c1e20f7c
SH
155/* RTT metrics are stored in milliseconds for user ABI, but used as jiffies */
156static inline unsigned long dst_metric_rtt(const struct dst_entry *dst, int metric)
157{
158 return msecs_to_jiffies(dst_metric(dst, metric));
159}
160
161static inline void set_dst_metric_rtt(struct dst_entry *dst, int metric,
162 unsigned long rtt)
163{
defb3519 164 dst_metric_set(dst, metric, jiffies_to_msecs(rtt));
c1e20f7c
SH
165}
166
1da177e4
LT
167static inline u32
168dst_allfrag(const struct dst_entry *dst)
169{
0c3adfb8 170 int ret = dst_feature(dst, RTAX_FEATURE_ALLFRAG);
1da177e4
LT
171 /* Yes, _exactly_. This is paranoia. */
172 barrier();
173 return ret;
174}
175
176static inline int
177dst_metric_locked(struct dst_entry *dst, int metric)
178{
179 return dst_metric(dst, RTAX_LOCK) & (1<<metric);
180}
181
182static inline void dst_hold(struct dst_entry * dst)
183{
5635c10d
ED
184 /*
185 * If your kernel compilation stops here, please check
186 * __pad_to_align_refcnt declaration in struct dst_entry
187 */
188 BUILD_BUG_ON(offsetof(struct dst_entry, __refcnt) & 63);
1da177e4
LT
189 atomic_inc(&dst->__refcnt);
190}
191
03f49f34
PE
192static inline void dst_use(struct dst_entry *dst, unsigned long time)
193{
194 dst_hold(dst);
195 dst->__use++;
196 dst->lastuse = time;
197}
198
7fee226a
ED
199static inline void dst_use_noref(struct dst_entry *dst, unsigned long time)
200{
201 dst->__use++;
202 dst->lastuse = time;
203}
204
1da177e4
LT
205static inline
206struct dst_entry * dst_clone(struct dst_entry * dst)
207{
208 if (dst)
209 atomic_inc(&dst->__refcnt);
210 return dst;
211}
212
8d330868 213extern void dst_release(struct dst_entry *dst);
7fee226a
ED
214
215static inline void refdst_drop(unsigned long refdst)
216{
217 if (!(refdst & SKB_DST_NOREF))
218 dst_release((struct dst_entry *)(refdst & SKB_DST_PTRMASK));
219}
220
221/**
222 * skb_dst_drop - drops skb dst
223 * @skb: buffer
224 *
225 * Drops dst reference count if a reference was taken.
226 */
adf30907
ED
227static inline void skb_dst_drop(struct sk_buff *skb)
228{
7fee226a
ED
229 if (skb->_skb_refdst) {
230 refdst_drop(skb->_skb_refdst);
231 skb->_skb_refdst = 0UL;
232 }
233}
234
235static inline void skb_dst_copy(struct sk_buff *nskb, const struct sk_buff *oskb)
236{
237 nskb->_skb_refdst = oskb->_skb_refdst;
238 if (!(nskb->_skb_refdst & SKB_DST_NOREF))
239 dst_clone(skb_dst(nskb));
240}
241
242/**
243 * skb_dst_force - makes sure skb dst is refcounted
244 * @skb: buffer
245 *
246 * If dst is not yet refcounted, let's do it
247 */
248static inline void skb_dst_force(struct sk_buff *skb)
249{
250 if (skb_dst_is_noref(skb)) {
251 WARN_ON(!rcu_read_lock_held());
252 skb->_skb_refdst &= ~SKB_DST_NOREF;
253 dst_clone(skb_dst(skb));
254 }
adf30907 255}
1da177e4 256
d19d56dd 257
290b895e
ED
258/**
259 * __skb_tunnel_rx - prepare skb for rx reinsert
260 * @skb: buffer
261 * @dev: tunnel device
262 *
263 * After decapsulation, packet is going to re-enter (netif_rx()) our stack,
264 * so make some cleanups. (no accounting done)
265 */
266static inline void __skb_tunnel_rx(struct sk_buff *skb, struct net_device *dev)
267{
268 skb->dev = dev;
269 skb->rxhash = 0;
270 skb_set_queue_mapping(skb, 0);
271 skb_dst_drop(skb);
272 nf_reset(skb);
273}
274
d19d56dd
ED
275/**
276 * skb_tunnel_rx - prepare skb for rx reinsert
277 * @skb: buffer
278 * @dev: tunnel device
279 *
280 * After decapsulation, packet is going to re-enter (netif_rx()) our stack,
281 * so make some cleanups, and perform accounting.
290b895e 282 * Note: this accounting is not SMP safe.
d19d56dd
ED
283 */
284static inline void skb_tunnel_rx(struct sk_buff *skb, struct net_device *dev)
285{
d19d56dd
ED
286 /* TODO : stats should be SMP safe */
287 dev->stats.rx_packets++;
288 dev->stats.rx_bytes += skb->len;
290b895e 289 __skb_tunnel_rx(skb, dev);
d19d56dd
ED
290}
291
1da177e4
LT
292/* Children define the path of the packet through the
293 * Linux networking. Thus, destinations are stackable.
294 */
295
8764ab2c 296static inline struct dst_entry *skb_dst_pop(struct sk_buff *skb)
1da177e4 297{
8764ab2c 298 struct dst_entry *child = skb_dst(skb)->child;
1da177e4 299
8764ab2c 300 skb_dst_drop(skb);
1da177e4
LT
301 return child;
302}
303
352e512c 304extern int dst_discard(struct sk_buff *skb);
1da177e4
LT
305extern void * dst_alloc(struct dst_ops * ops);
306extern void __dst_free(struct dst_entry * dst);
307extern struct dst_entry *dst_destroy(struct dst_entry * dst);
308
309static inline void dst_free(struct dst_entry * dst)
310{
311 if (dst->obsolete > 1)
312 return;
313 if (!atomic_read(&dst->__refcnt)) {
314 dst = dst_destroy(dst);
315 if (!dst)
316 return;
317 }
318 __dst_free(dst);
319}
320
321static inline void dst_rcu_free(struct rcu_head *head)
322{
323 struct dst_entry *dst = container_of(head, struct dst_entry, rcu_head);
324 dst_free(dst);
325}
326
327static inline void dst_confirm(struct dst_entry *dst)
328{
329 if (dst)
330 neigh_confirm(dst->neighbour);
331}
332
1da177e4
LT
333static inline void dst_link_failure(struct sk_buff *skb)
334{
adf30907 335 struct dst_entry *dst = skb_dst(skb);
1da177e4
LT
336 if (dst && dst->ops && dst->ops->link_failure)
337 dst->ops->link_failure(skb);
338}
339
340static inline void dst_set_expires(struct dst_entry *dst, int timeout)
341{
342 unsigned long expires = jiffies + timeout;
343
344 if (expires == 0)
345 expires = 1;
346
347 if (dst->expires == 0 || time_before(expires, dst->expires))
348 dst->expires = expires;
349}
350
351/* Output packet to network from transport. */
352static inline int dst_output(struct sk_buff *skb)
353{
adf30907 354 return skb_dst(skb)->output(skb);
1da177e4
LT
355}
356
357/* Input packet from network to transport. */
358static inline int dst_input(struct sk_buff *skb)
359{
adf30907 360 return skb_dst(skb)->input(skb);
1da177e4
LT
361}
362
363static inline struct dst_entry *dst_check(struct dst_entry *dst, u32 cookie)
364{
365 if (dst->obsolete)
366 dst = dst->ops->check(dst, cookie);
367 return dst;
368}
369
370extern void dst_init(void);
371
815f4e57
HX
372/* Flags for xfrm_lookup flags argument. */
373enum {
374 XFRM_LOOKUP_WAIT = 1 << 0,
8b7817f3 375 XFRM_LOOKUP_ICMP = 1 << 1,
815f4e57
HX
376};
377
1da177e4
LT
378struct flowi;
379#ifndef CONFIG_XFRM
52479b62
AD
380static inline int xfrm_lookup(struct net *net, struct dst_entry **dst_p,
381 struct flowi *fl, struct sock *sk, int flags)
1da177e4
LT
382{
383 return 0;
384}
52479b62
AD
385static inline int __xfrm_lookup(struct net *net, struct dst_entry **dst_p,
386 struct flowi *fl, struct sock *sk, int flags)
14e50e57
DM
387{
388 return 0;
389}
1da177e4 390#else
52479b62
AD
391extern int xfrm_lookup(struct net *net, struct dst_entry **dst_p,
392 struct flowi *fl, struct sock *sk, int flags);
393extern int __xfrm_lookup(struct net *net, struct dst_entry **dst_p,
394 struct flowi *fl, struct sock *sk, int flags);
1da177e4
LT
395#endif
396#endif
397
398#endif /* _NET_DST_H */
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