Commit | Line | Data |
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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 | ||
14c85021 | 11 | #include <linux/netdevice.h> |
1da177e4 LT |
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 | ||
36 | struct sk_buff; | |
37 | ||
38 | struct dst_entry | |
39 | { | |
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 LT |
45 | int flags; |
46 | #define DST_HOST 1 | |
47 | #define DST_NOXFRM 2 | |
48 | #define DST_NOPOLICY 4 | |
49 | #define DST_NOHASH 8 | |
1da177e4 LT |
50 | unsigned long expires; |
51 | ||
52 | unsigned short header_len; /* more space at head required */ | |
1b5c2299 | 53 | unsigned short nfheader_len; /* more non-fragment space at head required */ |
1da177e4 LT |
54 | unsigned short trailer_len; /* space to reserve at tail */ |
55 | ||
56 | u32 metrics[RTAX_MAX]; | |
57 | struct dst_entry *path; | |
58 | ||
59 | unsigned long rate_last; /* rate limiting for ICMP */ | |
60 | unsigned long rate_tokens; | |
61 | ||
1da177e4 LT |
62 | struct neighbour *neighbour; |
63 | struct hh_cache *hh; | |
64 | struct xfrm_state *xfrm; | |
65 | ||
66 | int (*input)(struct sk_buff*); | |
67 | int (*output)(struct sk_buff*); | |
68 | ||
69 | #ifdef CONFIG_NET_CLS_ROUTE | |
70 | __u32 tclassid; | |
71 | #endif | |
72 | ||
73 | struct dst_ops *ops; | |
1da177e4 | 74 | |
1e19e02c ED |
75 | unsigned long lastuse; |
76 | atomic_t __refcnt; /* client references */ | |
77 | int __use; | |
78 | union { | |
79 | struct dst_entry *next; | |
80 | struct rtable *rt_next; | |
81 | struct rt6_info *rt6_next; | |
82 | struct dn_route *dn_next; | |
83 | }; | |
1da177e4 LT |
84 | char info[0]; |
85 | }; | |
86 | ||
87 | ||
88 | struct dst_ops | |
89 | { | |
90 | unsigned short family; | |
d77072ec | 91 | __be16 protocol; |
1da177e4 LT |
92 | unsigned gc_thresh; |
93 | ||
94 | int (*gc)(void); | |
95 | struct dst_entry * (*check)(struct dst_entry *, __u32 cookie); | |
96 | void (*destroy)(struct dst_entry *); | |
97 | void (*ifdown)(struct dst_entry *, | |
98 | struct net_device *dev, int how); | |
99 | struct dst_entry * (*negative_advice)(struct dst_entry *); | |
100 | void (*link_failure)(struct sk_buff *); | |
101 | void (*update_pmtu)(struct dst_entry *dst, u32 mtu); | |
1da177e4 LT |
102 | int entry_size; |
103 | ||
104 | atomic_t entries; | |
e18b890b | 105 | struct kmem_cache *kmem_cachep; |
1da177e4 LT |
106 | }; |
107 | ||
108 | #ifdef __KERNEL__ | |
109 | ||
110 | static inline u32 | |
111 | dst_metric(const struct dst_entry *dst, int metric) | |
112 | { | |
113 | return dst->metrics[metric-1]; | |
114 | } | |
115 | ||
116 | static inline u32 dst_mtu(const struct dst_entry *dst) | |
117 | { | |
118 | u32 mtu = dst_metric(dst, RTAX_MTU); | |
119 | /* | |
120 | * Alexey put it here, so ask him about it :) | |
121 | */ | |
122 | barrier(); | |
123 | return mtu; | |
124 | } | |
125 | ||
126 | static inline u32 | |
127 | dst_allfrag(const struct dst_entry *dst) | |
128 | { | |
129 | int ret = dst_metric(dst, RTAX_FEATURES) & RTAX_FEATURE_ALLFRAG; | |
130 | /* Yes, _exactly_. This is paranoia. */ | |
131 | barrier(); | |
132 | return ret; | |
133 | } | |
134 | ||
135 | static inline int | |
136 | dst_metric_locked(struct dst_entry *dst, int metric) | |
137 | { | |
138 | return dst_metric(dst, RTAX_LOCK) & (1<<metric); | |
139 | } | |
140 | ||
141 | static inline void dst_hold(struct dst_entry * dst) | |
142 | { | |
143 | atomic_inc(&dst->__refcnt); | |
144 | } | |
145 | ||
146 | static inline | |
147 | struct dst_entry * dst_clone(struct dst_entry * dst) | |
148 | { | |
149 | if (dst) | |
150 | atomic_inc(&dst->__refcnt); | |
151 | return dst; | |
152 | } | |
153 | ||
154 | static inline | |
155 | void dst_release(struct dst_entry * dst) | |
156 | { | |
157 | if (dst) { | |
158 | WARN_ON(atomic_read(&dst->__refcnt) < 1); | |
159 | smp_mb__before_atomic_dec(); | |
160 | atomic_dec(&dst->__refcnt); | |
161 | } | |
162 | } | |
163 | ||
164 | /* Children define the path of the packet through the | |
165 | * Linux networking. Thus, destinations are stackable. | |
166 | */ | |
167 | ||
168 | static inline struct dst_entry *dst_pop(struct dst_entry *dst) | |
169 | { | |
170 | struct dst_entry *child = dst_clone(dst->child); | |
171 | ||
172 | dst_release(dst); | |
173 | return child; | |
174 | } | |
175 | ||
176 | extern void * dst_alloc(struct dst_ops * ops); | |
177 | extern void __dst_free(struct dst_entry * dst); | |
178 | extern struct dst_entry *dst_destroy(struct dst_entry * dst); | |
179 | ||
180 | static inline void dst_free(struct dst_entry * dst) | |
181 | { | |
182 | if (dst->obsolete > 1) | |
183 | return; | |
184 | if (!atomic_read(&dst->__refcnt)) { | |
185 | dst = dst_destroy(dst); | |
186 | if (!dst) | |
187 | return; | |
188 | } | |
189 | __dst_free(dst); | |
190 | } | |
191 | ||
192 | static inline void dst_rcu_free(struct rcu_head *head) | |
193 | { | |
194 | struct dst_entry *dst = container_of(head, struct dst_entry, rcu_head); | |
195 | dst_free(dst); | |
196 | } | |
197 | ||
198 | static inline void dst_confirm(struct dst_entry *dst) | |
199 | { | |
200 | if (dst) | |
201 | neigh_confirm(dst->neighbour); | |
202 | } | |
203 | ||
204 | static inline void dst_negative_advice(struct dst_entry **dst_p) | |
205 | { | |
206 | struct dst_entry * dst = *dst_p; | |
207 | if (dst && dst->ops->negative_advice) | |
208 | *dst_p = dst->ops->negative_advice(dst); | |
209 | } | |
210 | ||
211 | static inline void dst_link_failure(struct sk_buff *skb) | |
212 | { | |
213 | struct dst_entry * dst = skb->dst; | |
214 | if (dst && dst->ops && dst->ops->link_failure) | |
215 | dst->ops->link_failure(skb); | |
216 | } | |
217 | ||
218 | static inline void dst_set_expires(struct dst_entry *dst, int timeout) | |
219 | { | |
220 | unsigned long expires = jiffies + timeout; | |
221 | ||
222 | if (expires == 0) | |
223 | expires = 1; | |
224 | ||
225 | if (dst->expires == 0 || time_before(expires, dst->expires)) | |
226 | dst->expires = expires; | |
227 | } | |
228 | ||
229 | /* Output packet to network from transport. */ | |
230 | static inline int dst_output(struct sk_buff *skb) | |
231 | { | |
16a6677f | 232 | return skb->dst->output(skb); |
1da177e4 LT |
233 | } |
234 | ||
235 | /* Input packet from network to transport. */ | |
236 | static inline int dst_input(struct sk_buff *skb) | |
237 | { | |
238 | int err; | |
239 | ||
240 | for (;;) { | |
241 | err = skb->dst->input(skb); | |
242 | ||
243 | if (likely(err == 0)) | |
244 | return err; | |
245 | /* Oh, Jamal... Seems, I will not forgive you this mess. :-) */ | |
246 | if (unlikely(err != NET_XMIT_BYPASS)) | |
247 | return err; | |
248 | } | |
249 | } | |
250 | ||
251 | static inline struct dst_entry *dst_check(struct dst_entry *dst, u32 cookie) | |
252 | { | |
253 | if (dst->obsolete) | |
254 | dst = dst->ops->check(dst, cookie); | |
255 | return dst; | |
256 | } | |
257 | ||
258 | extern void dst_init(void); | |
259 | ||
260 | struct flowi; | |
261 | #ifndef CONFIG_XFRM | |
262 | static inline int xfrm_lookup(struct dst_entry **dst_p, struct flowi *fl, | |
263 | struct sock *sk, int flags) | |
264 | { | |
265 | return 0; | |
266 | } | |
14e50e57 DM |
267 | static inline int __xfrm_lookup(struct dst_entry **dst_p, struct flowi *fl, |
268 | struct sock *sk, int flags) | |
269 | { | |
270 | return 0; | |
271 | } | |
1da177e4 LT |
272 | #else |
273 | extern int xfrm_lookup(struct dst_entry **dst_p, struct flowi *fl, | |
274 | struct sock *sk, int flags); | |
14e50e57 DM |
275 | extern int __xfrm_lookup(struct dst_entry **dst_p, struct flowi *fl, |
276 | struct sock *sk, int flags); | |
1da177e4 LT |
277 | #endif |
278 | #endif | |
279 | ||
280 | #endif /* _NET_DST_H */ |