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 | { | |
40 | struct dst_entry *next; | |
41 | atomic_t __refcnt; /* client references */ | |
42 | int __use; | |
43 | struct dst_entry *child; | |
44 | struct net_device *dev; | |
c4d54110 HX |
45 | short error; |
46 | short obsolete; | |
1da177e4 LT |
47 | int flags; |
48 | #define DST_HOST 1 | |
49 | #define DST_NOXFRM 2 | |
50 | #define DST_NOPOLICY 4 | |
51 | #define DST_NOHASH 8 | |
52 | #define DST_BALANCED 0x10 | |
53 | unsigned long lastuse; | |
54 | unsigned long expires; | |
55 | ||
56 | unsigned short header_len; /* more space at head required */ | |
1b5c2299 | 57 | unsigned short nfheader_len; /* more non-fragment space at head required */ |
1da177e4 LT |
58 | unsigned short trailer_len; /* space to reserve at tail */ |
59 | ||
60 | u32 metrics[RTAX_MAX]; | |
61 | struct dst_entry *path; | |
62 | ||
63 | unsigned long rate_last; /* rate limiting for ICMP */ | |
64 | unsigned long rate_tokens; | |
65 | ||
1da177e4 LT |
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; | |
d77072ec | 87 | __be16 protocol; |
1da177e4 LT |
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); | |
1da177e4 LT |
98 | int entry_size; |
99 | ||
100 | atomic_t entries; | |
101 | kmem_cache_t *kmem_cachep; | |
102 | }; | |
103 | ||
104 | #ifdef __KERNEL__ | |
105 | ||
106 | static inline u32 | |
107 | dst_metric(const struct dst_entry *dst, int metric) | |
108 | { | |
109 | return dst->metrics[metric-1]; | |
110 | } | |
111 | ||
112 | static inline u32 dst_mtu(const struct dst_entry *dst) | |
113 | { | |
114 | u32 mtu = dst_metric(dst, RTAX_MTU); | |
115 | /* | |
116 | * Alexey put it here, so ask him about it :) | |
117 | */ | |
118 | barrier(); | |
119 | return mtu; | |
120 | } | |
121 | ||
122 | static inline u32 | |
123 | dst_allfrag(const struct dst_entry *dst) | |
124 | { | |
125 | int ret = dst_metric(dst, RTAX_FEATURES) & RTAX_FEATURE_ALLFRAG; | |
126 | /* Yes, _exactly_. This is paranoia. */ | |
127 | barrier(); | |
128 | return ret; | |
129 | } | |
130 | ||
131 | static inline int | |
132 | dst_metric_locked(struct dst_entry *dst, int metric) | |
133 | { | |
134 | return dst_metric(dst, RTAX_LOCK) & (1<<metric); | |
135 | } | |
136 | ||
137 | static inline void dst_hold(struct dst_entry * dst) | |
138 | { | |
139 | atomic_inc(&dst->__refcnt); | |
140 | } | |
141 | ||
142 | static inline | |
143 | struct dst_entry * dst_clone(struct dst_entry * dst) | |
144 | { | |
145 | if (dst) | |
146 | atomic_inc(&dst->__refcnt); | |
147 | return dst; | |
148 | } | |
149 | ||
150 | static inline | |
151 | void dst_release(struct dst_entry * dst) | |
152 | { | |
153 | if (dst) { | |
154 | WARN_ON(atomic_read(&dst->__refcnt) < 1); | |
155 | smp_mb__before_atomic_dec(); | |
156 | atomic_dec(&dst->__refcnt); | |
157 | } | |
158 | } | |
159 | ||
160 | /* Children define the path of the packet through the | |
161 | * Linux networking. Thus, destinations are stackable. | |
162 | */ | |
163 | ||
164 | static inline struct dst_entry *dst_pop(struct dst_entry *dst) | |
165 | { | |
166 | struct dst_entry *child = dst_clone(dst->child); | |
167 | ||
168 | dst_release(dst); | |
169 | return child; | |
170 | } | |
171 | ||
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); | |
175 | ||
176 | static inline void dst_free(struct dst_entry * dst) | |
177 | { | |
178 | if (dst->obsolete > 1) | |
179 | return; | |
180 | if (!atomic_read(&dst->__refcnt)) { | |
181 | dst = dst_destroy(dst); | |
182 | if (!dst) | |
183 | return; | |
184 | } | |
185 | __dst_free(dst); | |
186 | } | |
187 | ||
188 | static inline void dst_rcu_free(struct rcu_head *head) | |
189 | { | |
190 | struct dst_entry *dst = container_of(head, struct dst_entry, rcu_head); | |
191 | dst_free(dst); | |
192 | } | |
193 | ||
194 | static inline void dst_confirm(struct dst_entry *dst) | |
195 | { | |
196 | if (dst) | |
197 | neigh_confirm(dst->neighbour); | |
198 | } | |
199 | ||
200 | static inline void dst_negative_advice(struct dst_entry **dst_p) | |
201 | { | |
202 | struct dst_entry * dst = *dst_p; | |
203 | if (dst && dst->ops->negative_advice) | |
204 | *dst_p = dst->ops->negative_advice(dst); | |
205 | } | |
206 | ||
207 | static inline void dst_link_failure(struct sk_buff *skb) | |
208 | { | |
209 | struct dst_entry * dst = skb->dst; | |
210 | if (dst && dst->ops && dst->ops->link_failure) | |
211 | dst->ops->link_failure(skb); | |
212 | } | |
213 | ||
214 | static inline void dst_set_expires(struct dst_entry *dst, int timeout) | |
215 | { | |
216 | unsigned long expires = jiffies + timeout; | |
217 | ||
218 | if (expires == 0) | |
219 | expires = 1; | |
220 | ||
221 | if (dst->expires == 0 || time_before(expires, dst->expires)) | |
222 | dst->expires = expires; | |
223 | } | |
224 | ||
225 | /* Output packet to network from transport. */ | |
226 | static inline int dst_output(struct sk_buff *skb) | |
227 | { | |
16a6677f | 228 | return skb->dst->output(skb); |
1da177e4 LT |
229 | } |
230 | ||
231 | /* Input packet from network to transport. */ | |
232 | static inline int dst_input(struct sk_buff *skb) | |
233 | { | |
234 | int err; | |
235 | ||
236 | for (;;) { | |
237 | err = skb->dst->input(skb); | |
238 | ||
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; | |
244 | } | |
245 | } | |
246 | ||
247 | static inline struct dst_entry *dst_check(struct dst_entry *dst, u32 cookie) | |
248 | { | |
249 | if (dst->obsolete) | |
250 | dst = dst->ops->check(dst, cookie); | |
251 | return dst; | |
252 | } | |
253 | ||
254 | extern void dst_init(void); | |
255 | ||
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) | |
260 | { | |
261 | return 0; | |
262 | } | |
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 | |
268 | ||
269 | #endif /* _NET_DST_H */ |