[PATCH] uml: add -ffreestanding to CFLAGS
[linux/fpc-iii.git] / include / net / dst.h
blob5161e89017f934cb6be31560961b52906a56dbdd
1 /*
2 * net/dst.h Protocol independent destination cache definitions.
4 * Authors: Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
6 */
8 #ifndef _NET_DST_H
9 #define _NET_DST_H
11 #include <linux/config.h>
12 #include <linux/netdevice.h>
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>
20 * 0 - no debugging messages
21 * 1 - rare events and bugs (default)
22 * 2 - trace mode.
24 #define RT_CACHE_DEBUG 0
26 #define DST_GC_MIN (HZ/10)
27 #define DST_GC_INC (HZ/2)
28 #define DST_GC_MAX (120*HZ)
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.
37 struct sk_buff;
39 struct dst_entry
41 struct dst_entry *next;
42 atomic_t __refcnt; /* client references */
43 int __use;
44 struct dst_entry *child;
45 struct net_device *dev;
46 short error;
47 short obsolete;
48 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;
57 unsigned short header_len; /* more space at head required */
58 unsigned short trailer_len; /* space to reserve at tail */
60 u32 metrics[RTAX_MAX];
61 struct dst_entry *path;
63 unsigned long rate_last; /* rate limiting for ICMP */
64 unsigned long rate_tokens;
66 struct neighbour *neighbour;
67 struct hh_cache *hh;
68 struct xfrm_state *xfrm;
70 int (*input)(struct sk_buff*);
71 int (*output)(struct sk_buff*);
73 #ifdef CONFIG_NET_CLS_ROUTE
74 __u32 tclassid;
75 #endif
77 struct dst_ops *ops;
78 struct rcu_head rcu_head;
80 char info[0];
84 struct dst_ops
86 unsigned short family;
87 unsigned short protocol;
88 unsigned gc_thresh;
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);
98 int entry_size;
100 atomic_t entries;
101 kmem_cache_t *kmem_cachep;
104 #ifdef __KERNEL__
106 static inline u32
107 dst_metric(const struct dst_entry *dst, int metric)
109 return dst->metrics[metric-1];
112 static inline u32 dst_mtu(const struct dst_entry *dst)
114 u32 mtu = dst_metric(dst, RTAX_MTU);
116 * Alexey put it here, so ask him about it :)
118 barrier();
119 return mtu;
122 static inline u32
123 dst_allfrag(const struct dst_entry *dst)
125 int ret = dst_metric(dst, RTAX_FEATURES) & RTAX_FEATURE_ALLFRAG;
126 /* Yes, _exactly_. This is paranoia. */
127 barrier();
128 return ret;
131 static inline int
132 dst_metric_locked(struct dst_entry *dst, int metric)
134 return dst_metric(dst, RTAX_LOCK) & (1<<metric);
137 static inline void dst_hold(struct dst_entry * dst)
139 atomic_inc(&dst->__refcnt);
142 static inline
143 struct dst_entry * dst_clone(struct dst_entry * dst)
145 if (dst)
146 atomic_inc(&dst->__refcnt);
147 return dst;
150 static inline
151 void dst_release(struct dst_entry * dst)
153 if (dst) {
154 WARN_ON(atomic_read(&dst->__refcnt) < 1);
155 smp_mb__before_atomic_dec();
156 atomic_dec(&dst->__refcnt);
160 /* Children define the path of the packet through the
161 * Linux networking. Thus, destinations are stackable.
164 static inline struct dst_entry *dst_pop(struct dst_entry *dst)
166 struct dst_entry *child = dst_clone(dst->child);
168 dst_release(dst);
169 return child;
172 extern void * dst_alloc(struct dst_ops * ops);
173 extern void __dst_free(struct dst_entry * dst);
174 extern struct dst_entry *dst_destroy(struct dst_entry * dst);
176 static inline void dst_free(struct dst_entry * dst)
178 if (dst->obsolete > 1)
179 return;
180 if (!atomic_read(&dst->__refcnt)) {
181 dst = dst_destroy(dst);
182 if (!dst)
183 return;
185 __dst_free(dst);
188 static inline void dst_rcu_free(struct rcu_head *head)
190 struct dst_entry *dst = container_of(head, struct dst_entry, rcu_head);
191 dst_free(dst);
194 static inline void dst_confirm(struct dst_entry *dst)
196 if (dst)
197 neigh_confirm(dst->neighbour);
200 static inline void dst_negative_advice(struct dst_entry **dst_p)
202 struct dst_entry * dst = *dst_p;
203 if (dst && dst->ops->negative_advice)
204 *dst_p = dst->ops->negative_advice(dst);
207 static inline void dst_link_failure(struct sk_buff *skb)
209 struct dst_entry * dst = skb->dst;
210 if (dst && dst->ops && dst->ops->link_failure)
211 dst->ops->link_failure(skb);
214 static inline void dst_set_expires(struct dst_entry *dst, int timeout)
216 unsigned long expires = jiffies + timeout;
218 if (expires == 0)
219 expires = 1;
221 if (dst->expires == 0 || time_before(expires, dst->expires))
222 dst->expires = expires;
225 /* Output packet to network from transport. */
226 static inline int dst_output(struct sk_buff *skb)
228 return skb->dst->output(skb);
231 /* Input packet from network to transport. */
232 static inline int dst_input(struct sk_buff *skb)
234 int err;
236 for (;;) {
237 err = skb->dst->input(skb);
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;
247 static inline struct dst_entry *dst_check(struct dst_entry *dst, u32 cookie)
249 if (dst->obsolete)
250 dst = dst->ops->check(dst, cookie);
251 return dst;
254 extern void dst_init(void);
256 struct flowi;
257 #ifndef CONFIG_XFRM
258 static inline int xfrm_lookup(struct dst_entry **dst_p, struct flowi *fl,
259 struct sock *sk, int flags)
261 return 0;
263 #else
264 extern int xfrm_lookup(struct dst_entry **dst_p, struct flowi *fl,
265 struct sock *sk, int flags);
266 #endif
267 #endif
269 #endif /* _NET_DST_H */