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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
Alexey Dobriyan86393e52009-08-29 01:34:49 +000011#include <net/dst_ops.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{
Eric Dumazet1e19e022007-02-09 16:26:55 -080041 struct rcu_head rcu_head;
Linus Torvalds1da177e2005-04-16 15:20:36 -070042 struct dst_entry *child;
43 struct net_device *dev;
Herbert Xuc4d54112005-04-19 20:46:37 -070044 short error;
45 short obsolete;
Linus Torvalds1da177e2005-04-16 15:20:36 -070046 int flags;
47#define DST_HOST 1
48#define DST_NOXFRM 2
49#define DST_NOPOLICY 4
50#define DST_NOHASH 8
Linus Torvalds1da177e2005-04-16 15:20:36 -070051 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
Eric Dumazet69a73822008-01-22 06:18:34 -080056 unsigned int rate_tokens;
Zhang Yanminf1dd9c32008-03-12 22:52:37 -070057 unsigned long rate_last; /* rate limiting for ICMP */
Eric Dumazet69a73822008-01-22 06:18:34 -080058
Zhang Yanminf1dd9c32008-03-12 22:52:37 -070059 struct dst_entry *path;
Linus Torvalds1da177e2005-04-16 15:20:36 -070060
Linus Torvalds1da177e2005-04-16 15:20:36 -070061 struct neighbour *neighbour;
62 struct hh_cache *hh;
Alexey Dobriyandef8b4f2008-10-28 13:24:06 -070063#ifdef CONFIG_XFRM
Linus Torvalds1da177e2005-04-16 15:20:36 -070064 struct xfrm_state *xfrm;
Eric Dumazet5635c102008-11-16 19:46:36 -080065#else
66 void *__pad1;
Alexey Dobriyandef8b4f2008-10-28 13:24:06 -070067#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -070068 int (*input)(struct sk_buff*);
69 int (*output)(struct sk_buff*);
70
Linus Torvalds1da177e2005-04-16 15:20:36 -070071 struct dst_ops *ops;
Zhang Yanminf1dd9c32008-03-12 22:52:37 -070072
73 u32 metrics[RTAX_MAX];
74
75#ifdef CONFIG_NET_CLS_ROUTE
76 __u32 tclassid;
Eric Dumazet5635c102008-11-16 19:46:36 -080077#else
78 __u32 __pad2;
Zhang Yanminf1dd9c32008-03-12 22:52:37 -070079#endif
80
Eric Dumazet5635c102008-11-16 19:46:36 -080081
82 /*
83 * Align __refcnt to a 64 bytes alignment
84 * (L1_CACHE_SIZE would be too much)
85 */
86#ifdef CONFIG_64BIT
87 long __pad_to_align_refcnt[2];
88#else
89 long __pad_to_align_refcnt[1];
90#endif
Zhang Yanminf1dd9c32008-03-12 22:52:37 -070091 /*
92 * __refcnt wants to be on a different cache line from
93 * input/output/ops or performance tanks badly
94 */
Eric Dumazet1e19e022007-02-09 16:26:55 -080095 atomic_t __refcnt; /* client references */
96 int __use;
Zhang Yanminf1dd9c32008-03-12 22:52:37 -070097 unsigned long lastuse;
Eric Dumazet1e19e022007-02-09 16:26:55 -080098 union {
99 struct dst_entry *next;
100 struct rtable *rt_next;
101 struct rt6_info *rt6_next;
102 struct dn_route *dn_next;
103 };
Linus Torvalds1da177e2005-04-16 15:20:36 -0700104};
105
Linus Torvalds1da177e2005-04-16 15:20:36 -0700106#ifdef __KERNEL__
107
108static inline u32
109dst_metric(const struct dst_entry *dst, int metric)
110{
111 return dst->metrics[metric-1];
112}
113
Gilad Ben-Yossef0c3adfb2009-10-28 04:15:23 +0000114static inline u32
115dst_feature(const struct dst_entry *dst, u32 feature)
116{
117 return dst_metric(dst, RTAX_FEATURES) & feature;
118}
119
Linus Torvalds1da177e2005-04-16 15:20:36 -0700120static inline u32 dst_mtu(const struct dst_entry *dst)
121{
122 u32 mtu = dst_metric(dst, RTAX_MTU);
123 /*
124 * Alexey put it here, so ask him about it :)
125 */
126 barrier();
127 return mtu;
128}
129
Stephen Hemmingerc1e20f72008-07-18 23:02:15 -0700130/* RTT metrics are stored in milliseconds for user ABI, but used as jiffies */
131static inline unsigned long dst_metric_rtt(const struct dst_entry *dst, int metric)
132{
133 return msecs_to_jiffies(dst_metric(dst, metric));
134}
135
136static inline void set_dst_metric_rtt(struct dst_entry *dst, int metric,
137 unsigned long rtt)
138{
139 dst->metrics[metric-1] = jiffies_to_msecs(rtt);
140}
141
Linus Torvalds1da177e2005-04-16 15:20:36 -0700142static inline u32
143dst_allfrag(const struct dst_entry *dst)
144{
Gilad Ben-Yossef0c3adfb2009-10-28 04:15:23 +0000145 int ret = dst_feature(dst, RTAX_FEATURE_ALLFRAG);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700146 /* Yes, _exactly_. This is paranoia. */
147 barrier();
148 return ret;
149}
150
151static inline int
152dst_metric_locked(struct dst_entry *dst, int metric)
153{
154 return dst_metric(dst, RTAX_LOCK) & (1<<metric);
155}
156
157static inline void dst_hold(struct dst_entry * dst)
158{
Eric Dumazet5635c102008-11-16 19:46:36 -0800159 /*
160 * If your kernel compilation stops here, please check
161 * __pad_to_align_refcnt declaration in struct dst_entry
162 */
163 BUILD_BUG_ON(offsetof(struct dst_entry, __refcnt) & 63);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700164 atomic_inc(&dst->__refcnt);
165}
166
Pavel Emelyanov03f49f32007-11-10 21:28:34 -0800167static inline void dst_use(struct dst_entry *dst, unsigned long time)
168{
169 dst_hold(dst);
170 dst->__use++;
171 dst->lastuse = time;
172}
173
Linus Torvalds1da177e2005-04-16 15:20:36 -0700174static inline
175struct dst_entry * dst_clone(struct dst_entry * dst)
176{
177 if (dst)
178 atomic_inc(&dst->__refcnt);
179 return dst;
180}
181
Ilpo Järvinen8d330862008-03-27 17:53:31 -0700182extern void dst_release(struct dst_entry *dst);
Eric Dumazetadf30902009-06-02 05:19:30 +0000183static inline void skb_dst_drop(struct sk_buff *skb)
184{
185 if (skb->_skb_dst)
186 dst_release(skb_dst(skb));
187 skb->_skb_dst = 0UL;
188}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700189
190/* Children define the path of the packet through the
191 * Linux networking. Thus, destinations are stackable.
192 */
193
194static inline struct dst_entry *dst_pop(struct dst_entry *dst)
195{
196 struct dst_entry *child = dst_clone(dst->child);
197
198 dst_release(dst);
199 return child;
200}
201
Herbert Xu352e5122007-11-13 21:34:06 -0800202extern int dst_discard(struct sk_buff *skb);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700203extern void * dst_alloc(struct dst_ops * ops);
204extern void __dst_free(struct dst_entry * dst);
205extern struct dst_entry *dst_destroy(struct dst_entry * dst);
206
207static inline void dst_free(struct dst_entry * dst)
208{
209 if (dst->obsolete > 1)
210 return;
211 if (!atomic_read(&dst->__refcnt)) {
212 dst = dst_destroy(dst);
213 if (!dst)
214 return;
215 }
216 __dst_free(dst);
217}
218
219static inline void dst_rcu_free(struct rcu_head *head)
220{
221 struct dst_entry *dst = container_of(head, struct dst_entry, rcu_head);
222 dst_free(dst);
223}
224
225static inline void dst_confirm(struct dst_entry *dst)
226{
227 if (dst)
228 neigh_confirm(dst->neighbour);
229}
230
Krishna Kumarea94ff32009-10-19 23:46:45 +0000231static inline void dst_negative_advice(struct dst_entry **dst_p,
232 struct sock *sk)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700233{
234 struct dst_entry * dst = *dst_p;
Krishna Kumarea94ff32009-10-19 23:46:45 +0000235 if (dst && dst->ops->negative_advice) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700236 *dst_p = dst->ops->negative_advice(dst);
Krishna Kumarea94ff32009-10-19 23:46:45 +0000237
238 if (dst != *dst_p) {
239 extern void sk_reset_txq(struct sock *sk);
240
241 sk_reset_txq(sk);
242 }
243 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700244}
245
246static inline void dst_link_failure(struct sk_buff *skb)
247{
Eric Dumazetadf30902009-06-02 05:19:30 +0000248 struct dst_entry *dst = skb_dst(skb);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700249 if (dst && dst->ops && dst->ops->link_failure)
250 dst->ops->link_failure(skb);
251}
252
253static inline void dst_set_expires(struct dst_entry *dst, int timeout)
254{
255 unsigned long expires = jiffies + timeout;
256
257 if (expires == 0)
258 expires = 1;
259
260 if (dst->expires == 0 || time_before(expires, dst->expires))
261 dst->expires = expires;
262}
263
264/* Output packet to network from transport. */
265static inline int dst_output(struct sk_buff *skb)
266{
Eric Dumazetadf30902009-06-02 05:19:30 +0000267 return skb_dst(skb)->output(skb);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700268}
269
270/* Input packet from network to transport. */
271static inline int dst_input(struct sk_buff *skb)
272{
Eric Dumazetadf30902009-06-02 05:19:30 +0000273 return skb_dst(skb)->input(skb);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700274}
275
276static inline struct dst_entry *dst_check(struct dst_entry *dst, u32 cookie)
277{
278 if (dst->obsolete)
279 dst = dst->ops->check(dst, cookie);
280 return dst;
281}
282
283extern void dst_init(void);
284
Herbert Xu815f4e52007-12-12 10:36:59 -0800285/* Flags for xfrm_lookup flags argument. */
286enum {
287 XFRM_LOOKUP_WAIT = 1 << 0,
Herbert Xu8b7817f2007-12-12 10:44:43 -0800288 XFRM_LOOKUP_ICMP = 1 << 1,
Herbert Xu815f4e52007-12-12 10:36:59 -0800289};
290
Linus Torvalds1da177e2005-04-16 15:20:36 -0700291struct flowi;
292#ifndef CONFIG_XFRM
Alexey Dobriyan52479b62008-11-25 17:35:18 -0800293static inline int xfrm_lookup(struct net *net, struct dst_entry **dst_p,
294 struct flowi *fl, struct sock *sk, int flags)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700295{
296 return 0;
297}
Alexey Dobriyan52479b62008-11-25 17:35:18 -0800298static inline int __xfrm_lookup(struct net *net, struct dst_entry **dst_p,
299 struct flowi *fl, struct sock *sk, int flags)
David S. Miller14e50e52007-05-24 18:17:54 -0700300{
301 return 0;
302}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700303#else
Alexey Dobriyan52479b62008-11-25 17:35:18 -0800304extern int xfrm_lookup(struct net *net, struct dst_entry **dst_p,
305 struct flowi *fl, struct sock *sk, int flags);
306extern int __xfrm_lookup(struct net *net, struct dst_entry **dst_p,
307 struct flowi *fl, struct sock *sk, int flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700308#endif
309#endif
310
311#endif /* _NET_DST_H */