net: Abstract default ADVMSS behind an accessor.
[GitHub/mt8127/android_kernel_alcatel_ttab.git] / include / net / dst.h
CommitLineData
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
86393e52 11#include <net/dst_ops.h>
14c85021 12#include <linux/netdevice.h>
1da177e4
LT
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>
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
fd2c3ef7 39struct dst_entry {
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 45 int flags;
c7d4426a
ED
46#define DST_HOST 0x0001
47#define DST_NOXFRM 0x0002
48#define DST_NOPOLICY 0x0004
49#define DST_NOHASH 0x0008
50#define DST_NOCACHE 0x0010
1da177e4
LT
51 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
69a73829 56 unsigned int rate_tokens;
f1dd9c37 57 unsigned long rate_last; /* rate limiting for ICMP */
69a73829 58
f1dd9c37 59 struct dst_entry *path;
1da177e4 60
1da177e4
LT
61 struct neighbour *neighbour;
62 struct hh_cache *hh;
def8b4fa 63#ifdef CONFIG_XFRM
1da177e4 64 struct xfrm_state *xfrm;
5635c10d
ED
65#else
66 void *__pad1;
def8b4fa 67#endif
1da177e4
LT
68 int (*input)(struct sk_buff*);
69 int (*output)(struct sk_buff*);
70
1da177e4 71 struct dst_ops *ops;
f1dd9c37 72
defb3519 73 u32 _metrics[RTAX_MAX];
f1dd9c37
ZY
74
75#ifdef CONFIG_NET_CLS_ROUTE
76 __u32 tclassid;
5635c10d
ED
77#else
78 __u32 __pad2;
f1dd9c37
ZY
79#endif
80
5635c10d
ED
81
82 /*
83 * Align __refcnt to a 64 bytes alignment
84 * (L1_CACHE_SIZE would be too much)
85 */
86#ifdef CONFIG_64BIT
5635c10d
ED
87 long __pad_to_align_refcnt[1];
88#endif
f1dd9c37
ZY
89 /*
90 * __refcnt wants to be on a different cache line from
91 * input/output/ops or performance tanks badly
92 */
1e19e02c
ED
93 atomic_t __refcnt; /* client references */
94 int __use;
f1dd9c37 95 unsigned long lastuse;
1e19e02c 96 union {
fc766e4c
ED
97 struct dst_entry *next;
98 struct rtable __rcu *rt_next;
99 struct rt6_info *rt6_next;
100 struct dn_route __rcu *dn_next;
1e19e02c 101 };
1da177e4
LT
102};
103
1da177e4
LT
104#ifdef __KERNEL__
105
106static inline u32
5170ae82 107dst_metric_raw(const struct dst_entry *dst, const int metric)
1da177e4 108{
defb3519
DM
109 return dst->_metrics[metric-1];
110}
111
5170ae82
DM
112static inline u32
113dst_metric(const struct dst_entry *dst, const int metric)
114{
0dbaee3b
DM
115 WARN_ON_ONCE(metric == RTAX_HOPLIMIT ||
116 metric == RTAX_ADVMSS);
5170ae82
DM
117 return dst_metric_raw(dst, metric);
118}
119
0dbaee3b
DM
120static inline u32
121dst_metric_advmss(const struct dst_entry *dst)
122{
123 u32 advmss = dst_metric_raw(dst, RTAX_ADVMSS);
124
125 if (!advmss)
126 advmss = dst->ops->default_advmss(dst);
127
128 return advmss;
129}
130
defb3519
DM
131static inline void dst_metric_set(struct dst_entry *dst, int metric, u32 val)
132{
133 dst->_metrics[metric-1] = val;
134}
135
136static inline void dst_import_metrics(struct dst_entry *dst, const u32 *src_metrics)
137{
138 memcpy(dst->_metrics, src_metrics, RTAX_MAX * sizeof(u32));
139}
140
141static inline void dst_copy_metrics(struct dst_entry *dest, const struct dst_entry *src)
142{
143 dst_import_metrics(dest, src->_metrics);
144}
145
146static inline u32 *dst_metrics_ptr(struct dst_entry *dst)
147{
148 return dst->_metrics;
1da177e4
LT
149}
150
0c3adfb8
GBY
151static inline u32
152dst_feature(const struct dst_entry *dst, u32 feature)
153{
bb5b7c11 154 return dst_metric(dst, RTAX_FEATURES) & feature;
0c3adfb8
GBY
155}
156
1da177e4
LT
157static inline u32 dst_mtu(const struct dst_entry *dst)
158{
159 u32 mtu = dst_metric(dst, RTAX_MTU);
160 /*
161 * Alexey put it here, so ask him about it :)
162 */
163 barrier();
164 return mtu;
165}
166
c1e20f7c
SH
167/* RTT metrics are stored in milliseconds for user ABI, but used as jiffies */
168static inline unsigned long dst_metric_rtt(const struct dst_entry *dst, int metric)
169{
170 return msecs_to_jiffies(dst_metric(dst, metric));
171}
172
173static inline void set_dst_metric_rtt(struct dst_entry *dst, int metric,
174 unsigned long rtt)
175{
defb3519 176 dst_metric_set(dst, metric, jiffies_to_msecs(rtt));
c1e20f7c
SH
177}
178
1da177e4
LT
179static inline u32
180dst_allfrag(const struct dst_entry *dst)
181{
0c3adfb8 182 int ret = dst_feature(dst, RTAX_FEATURE_ALLFRAG);
1da177e4
LT
183 /* Yes, _exactly_. This is paranoia. */
184 barrier();
185 return ret;
186}
187
188static inline int
189dst_metric_locked(struct dst_entry *dst, int metric)
190{
191 return dst_metric(dst, RTAX_LOCK) & (1<<metric);
192}
193
194static inline void dst_hold(struct dst_entry * dst)
195{
5635c10d
ED
196 /*
197 * If your kernel compilation stops here, please check
198 * __pad_to_align_refcnt declaration in struct dst_entry
199 */
200 BUILD_BUG_ON(offsetof(struct dst_entry, __refcnt) & 63);
1da177e4
LT
201 atomic_inc(&dst->__refcnt);
202}
203
03f49f34
PE
204static inline void dst_use(struct dst_entry *dst, unsigned long time)
205{
206 dst_hold(dst);
207 dst->__use++;
208 dst->lastuse = time;
209}
210
7fee226a
ED
211static inline void dst_use_noref(struct dst_entry *dst, unsigned long time)
212{
213 dst->__use++;
214 dst->lastuse = time;
215}
216
1da177e4
LT
217static inline
218struct dst_entry * dst_clone(struct dst_entry * dst)
219{
220 if (dst)
221 atomic_inc(&dst->__refcnt);
222 return dst;
223}
224
8d330868 225extern void dst_release(struct dst_entry *dst);
7fee226a
ED
226
227static inline void refdst_drop(unsigned long refdst)
228{
229 if (!(refdst & SKB_DST_NOREF))
230 dst_release((struct dst_entry *)(refdst & SKB_DST_PTRMASK));
231}
232
233/**
234 * skb_dst_drop - drops skb dst
235 * @skb: buffer
236 *
237 * Drops dst reference count if a reference was taken.
238 */
adf30907
ED
239static inline void skb_dst_drop(struct sk_buff *skb)
240{
7fee226a
ED
241 if (skb->_skb_refdst) {
242 refdst_drop(skb->_skb_refdst);
243 skb->_skb_refdst = 0UL;
244 }
245}
246
247static inline void skb_dst_copy(struct sk_buff *nskb, const struct sk_buff *oskb)
248{
249 nskb->_skb_refdst = oskb->_skb_refdst;
250 if (!(nskb->_skb_refdst & SKB_DST_NOREF))
251 dst_clone(skb_dst(nskb));
252}
253
254/**
255 * skb_dst_force - makes sure skb dst is refcounted
256 * @skb: buffer
257 *
258 * If dst is not yet refcounted, let's do it
259 */
260static inline void skb_dst_force(struct sk_buff *skb)
261{
262 if (skb_dst_is_noref(skb)) {
263 WARN_ON(!rcu_read_lock_held());
264 skb->_skb_refdst &= ~SKB_DST_NOREF;
265 dst_clone(skb_dst(skb));
266 }
adf30907 267}
1da177e4 268
d19d56dd 269
290b895e
ED
270/**
271 * __skb_tunnel_rx - prepare skb for rx reinsert
272 * @skb: buffer
273 * @dev: tunnel device
274 *
275 * After decapsulation, packet is going to re-enter (netif_rx()) our stack,
276 * so make some cleanups. (no accounting done)
277 */
278static inline void __skb_tunnel_rx(struct sk_buff *skb, struct net_device *dev)
279{
280 skb->dev = dev;
281 skb->rxhash = 0;
282 skb_set_queue_mapping(skb, 0);
283 skb_dst_drop(skb);
284 nf_reset(skb);
285}
286
d19d56dd
ED
287/**
288 * skb_tunnel_rx - prepare skb for rx reinsert
289 * @skb: buffer
290 * @dev: tunnel device
291 *
292 * After decapsulation, packet is going to re-enter (netif_rx()) our stack,
293 * so make some cleanups, and perform accounting.
290b895e 294 * Note: this accounting is not SMP safe.
d19d56dd
ED
295 */
296static inline void skb_tunnel_rx(struct sk_buff *skb, struct net_device *dev)
297{
d19d56dd
ED
298 /* TODO : stats should be SMP safe */
299 dev->stats.rx_packets++;
300 dev->stats.rx_bytes += skb->len;
290b895e 301 __skb_tunnel_rx(skb, dev);
d19d56dd
ED
302}
303
1da177e4
LT
304/* Children define the path of the packet through the
305 * Linux networking. Thus, destinations are stackable.
306 */
307
8764ab2c 308static inline struct dst_entry *skb_dst_pop(struct sk_buff *skb)
1da177e4 309{
8764ab2c 310 struct dst_entry *child = skb_dst(skb)->child;
1da177e4 311
8764ab2c 312 skb_dst_drop(skb);
1da177e4
LT
313 return child;
314}
315
352e512c 316extern int dst_discard(struct sk_buff *skb);
1da177e4
LT
317extern void * dst_alloc(struct dst_ops * ops);
318extern void __dst_free(struct dst_entry * dst);
319extern struct dst_entry *dst_destroy(struct dst_entry * dst);
320
321static inline void dst_free(struct dst_entry * dst)
322{
323 if (dst->obsolete > 1)
324 return;
325 if (!atomic_read(&dst->__refcnt)) {
326 dst = dst_destroy(dst);
327 if (!dst)
328 return;
329 }
330 __dst_free(dst);
331}
332
333static inline void dst_rcu_free(struct rcu_head *head)
334{
335 struct dst_entry *dst = container_of(head, struct dst_entry, rcu_head);
336 dst_free(dst);
337}
338
339static inline void dst_confirm(struct dst_entry *dst)
340{
341 if (dst)
342 neigh_confirm(dst->neighbour);
343}
344
1da177e4
LT
345static inline void dst_link_failure(struct sk_buff *skb)
346{
adf30907 347 struct dst_entry *dst = skb_dst(skb);
1da177e4
LT
348 if (dst && dst->ops && dst->ops->link_failure)
349 dst->ops->link_failure(skb);
350}
351
352static inline void dst_set_expires(struct dst_entry *dst, int timeout)
353{
354 unsigned long expires = jiffies + timeout;
355
356 if (expires == 0)
357 expires = 1;
358
359 if (dst->expires == 0 || time_before(expires, dst->expires))
360 dst->expires = expires;
361}
362
363/* Output packet to network from transport. */
364static inline int dst_output(struct sk_buff *skb)
365{
adf30907 366 return skb_dst(skb)->output(skb);
1da177e4
LT
367}
368
369/* Input packet from network to transport. */
370static inline int dst_input(struct sk_buff *skb)
371{
adf30907 372 return skb_dst(skb)->input(skb);
1da177e4
LT
373}
374
375static inline struct dst_entry *dst_check(struct dst_entry *dst, u32 cookie)
376{
377 if (dst->obsolete)
378 dst = dst->ops->check(dst, cookie);
379 return dst;
380}
381
382extern void dst_init(void);
383
815f4e57
HX
384/* Flags for xfrm_lookup flags argument. */
385enum {
386 XFRM_LOOKUP_WAIT = 1 << 0,
8b7817f3 387 XFRM_LOOKUP_ICMP = 1 << 1,
815f4e57
HX
388};
389
1da177e4
LT
390struct flowi;
391#ifndef CONFIG_XFRM
52479b62
AD
392static inline int xfrm_lookup(struct net *net, struct dst_entry **dst_p,
393 struct flowi *fl, struct sock *sk, int flags)
1da177e4
LT
394{
395 return 0;
396}
52479b62
AD
397static inline int __xfrm_lookup(struct net *net, struct dst_entry **dst_p,
398 struct flowi *fl, struct sock *sk, int flags)
14e50e57
DM
399{
400 return 0;
401}
1da177e4 402#else
52479b62
AD
403extern int xfrm_lookup(struct net *net, struct dst_entry **dst_p,
404 struct flowi *fl, struct sock *sk, int flags);
405extern int __xfrm_lookup(struct net *net, struct dst_entry **dst_p,
406 struct flowi *fl, struct sock *sk, int flags);
1da177e4
LT
407#endif
408#endif
409
410#endif /* _NET_DST_H */