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 | ||
11 | #include <linux/config.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 | ||
36 | struct sk_buff; | |
37 | ||
38 | struct dst_entry | |
39 | { | |
40 | struct dst_entry *next; | |
41 | atomic_t __refcnt; /* client references */ | |
42 | int __use; | |
43 | struct dst_entry *child; | |
44 | struct net_device *dev; | |
45 | int obsolete; | |
46 | int flags; | |
47 | #define DST_HOST 1 | |
48 | #define DST_NOXFRM 2 | |
49 | #define DST_NOPOLICY 4 | |
50 | #define DST_NOHASH 8 | |
51 | #define DST_BALANCED 0x10 | |
52 | unsigned long lastuse; | |
53 | unsigned long expires; | |
54 | ||
55 | unsigned short header_len; /* more space at head required */ | |
56 | unsigned short trailer_len; /* space to reserve at tail */ | |
57 | ||
58 | u32 metrics[RTAX_MAX]; | |
59 | struct dst_entry *path; | |
60 | ||
61 | unsigned long rate_last; /* rate limiting for ICMP */ | |
62 | unsigned long rate_tokens; | |
63 | ||
64 | int error; | |
65 | ||
66 | struct neighbour *neighbour; | |
67 | struct hh_cache *hh; | |
68 | struct xfrm_state *xfrm; | |
69 | ||
70 | int (*input)(struct sk_buff*); | |
71 | int (*output)(struct sk_buff*); | |
72 | ||
73 | #ifdef CONFIG_NET_CLS_ROUTE | |
74 | __u32 tclassid; | |
75 | #endif | |
76 | ||
77 | struct dst_ops *ops; | |
78 | struct rcu_head rcu_head; | |
79 | ||
80 | char info[0]; | |
81 | }; | |
82 | ||
83 | ||
84 | struct dst_ops | |
85 | { | |
86 | unsigned short family; | |
87 | unsigned short protocol; | |
88 | unsigned gc_thresh; | |
89 | ||
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 (*get_mss)(struct dst_entry *dst, u32 mtu); | |
99 | int entry_size; | |
100 | ||
101 | atomic_t entries; | |
102 | kmem_cache_t *kmem_cachep; | |
103 | }; | |
104 | ||
105 | #ifdef __KERNEL__ | |
106 | ||
107 | static inline u32 | |
108 | dst_metric(const struct dst_entry *dst, int metric) | |
109 | { | |
110 | return dst->metrics[metric-1]; | |
111 | } | |
112 | ||
113 | static inline u32 dst_mtu(const struct dst_entry *dst) | |
114 | { | |
115 | u32 mtu = dst_metric(dst, RTAX_MTU); | |
116 | /* | |
117 | * Alexey put it here, so ask him about it :) | |
118 | */ | |
119 | barrier(); | |
120 | return mtu; | |
121 | } | |
122 | ||
123 | static inline u32 | |
124 | dst_allfrag(const struct dst_entry *dst) | |
125 | { | |
126 | int ret = dst_metric(dst, RTAX_FEATURES) & RTAX_FEATURE_ALLFRAG; | |
127 | /* Yes, _exactly_. This is paranoia. */ | |
128 | barrier(); | |
129 | return ret; | |
130 | } | |
131 | ||
132 | static inline int | |
133 | dst_metric_locked(struct dst_entry *dst, int metric) | |
134 | { | |
135 | return dst_metric(dst, RTAX_LOCK) & (1<<metric); | |
136 | } | |
137 | ||
138 | static inline void dst_hold(struct dst_entry * dst) | |
139 | { | |
140 | atomic_inc(&dst->__refcnt); | |
141 | } | |
142 | ||
143 | static inline | |
144 | struct dst_entry * dst_clone(struct dst_entry * dst) | |
145 | { | |
146 | if (dst) | |
147 | atomic_inc(&dst->__refcnt); | |
148 | return dst; | |
149 | } | |
150 | ||
151 | static inline | |
152 | void dst_release(struct dst_entry * dst) | |
153 | { | |
154 | if (dst) { | |
155 | WARN_ON(atomic_read(&dst->__refcnt) < 1); | |
156 | smp_mb__before_atomic_dec(); | |
157 | atomic_dec(&dst->__refcnt); | |
158 | } | |
159 | } | |
160 | ||
161 | /* Children define the path of the packet through the | |
162 | * Linux networking. Thus, destinations are stackable. | |
163 | */ | |
164 | ||
165 | static inline struct dst_entry *dst_pop(struct dst_entry *dst) | |
166 | { | |
167 | struct dst_entry *child = dst_clone(dst->child); | |
168 | ||
169 | dst_release(dst); | |
170 | return child; | |
171 | } | |
172 | ||
173 | extern void * dst_alloc(struct dst_ops * ops); | |
174 | extern void __dst_free(struct dst_entry * dst); | |
175 | extern struct dst_entry *dst_destroy(struct dst_entry * dst); | |
176 | ||
177 | static inline void dst_free(struct dst_entry * dst) | |
178 | { | |
179 | if (dst->obsolete > 1) | |
180 | return; | |
181 | if (!atomic_read(&dst->__refcnt)) { | |
182 | dst = dst_destroy(dst); | |
183 | if (!dst) | |
184 | return; | |
185 | } | |
186 | __dst_free(dst); | |
187 | } | |
188 | ||
189 | static inline void dst_rcu_free(struct rcu_head *head) | |
190 | { | |
191 | struct dst_entry *dst = container_of(head, struct dst_entry, rcu_head); | |
192 | dst_free(dst); | |
193 | } | |
194 | ||
195 | static inline void dst_confirm(struct dst_entry *dst) | |
196 | { | |
197 | if (dst) | |
198 | neigh_confirm(dst->neighbour); | |
199 | } | |
200 | ||
201 | static inline void dst_negative_advice(struct dst_entry **dst_p) | |
202 | { | |
203 | struct dst_entry * dst = *dst_p; | |
204 | if (dst && dst->ops->negative_advice) | |
205 | *dst_p = dst->ops->negative_advice(dst); | |
206 | } | |
207 | ||
208 | static inline void dst_link_failure(struct sk_buff *skb) | |
209 | { | |
210 | struct dst_entry * dst = skb->dst; | |
211 | if (dst && dst->ops && dst->ops->link_failure) | |
212 | dst->ops->link_failure(skb); | |
213 | } | |
214 | ||
215 | static inline void dst_set_expires(struct dst_entry *dst, int timeout) | |
216 | { | |
217 | unsigned long expires = jiffies + timeout; | |
218 | ||
219 | if (expires == 0) | |
220 | expires = 1; | |
221 | ||
222 | if (dst->expires == 0 || time_before(expires, dst->expires)) | |
223 | dst->expires = expires; | |
224 | } | |
225 | ||
226 | /* Output packet to network from transport. */ | |
227 | static inline int dst_output(struct sk_buff *skb) | |
228 | { | |
229 | int err; | |
230 | ||
231 | for (;;) { | |
232 | err = skb->dst->output(skb); | |
233 | ||
234 | if (likely(err == 0)) | |
235 | return err; | |
236 | if (unlikely(err != NET_XMIT_BYPASS)) | |
237 | return err; | |
238 | } | |
239 | } | |
240 | ||
241 | /* Input packet from network to transport. */ | |
242 | static inline int dst_input(struct sk_buff *skb) | |
243 | { | |
244 | int err; | |
245 | ||
246 | for (;;) { | |
247 | err = skb->dst->input(skb); | |
248 | ||
249 | if (likely(err == 0)) | |
250 | return err; | |
251 | /* Oh, Jamal... Seems, I will not forgive you this mess. :-) */ | |
252 | if (unlikely(err != NET_XMIT_BYPASS)) | |
253 | return err; | |
254 | } | |
255 | } | |
256 | ||
257 | static inline struct dst_entry *dst_check(struct dst_entry *dst, u32 cookie) | |
258 | { | |
259 | if (dst->obsolete) | |
260 | dst = dst->ops->check(dst, cookie); | |
261 | return dst; | |
262 | } | |
263 | ||
264 | extern void dst_init(void); | |
265 | ||
266 | struct flowi; | |
267 | #ifndef CONFIG_XFRM | |
268 | static inline int xfrm_lookup(struct dst_entry **dst_p, struct flowi *fl, | |
269 | struct sock *sk, int flags) | |
270 | { | |
271 | return 0; | |
272 | } | |
273 | #else | |
274 | extern int xfrm_lookup(struct dst_entry **dst_p, struct flowi *fl, | |
275 | struct sock *sk, int flags); | |
276 | #endif | |
277 | #endif | |
278 | ||
279 | #endif /* _NET_DST_H */ |