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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>
187f1882 15#include <linux/bug.h>
1da177e4
LT
16#include <linux/jiffies.h>
17#include <net/neighbour.h>
18#include <asm/processor.h>
19
1da177e4
LT
20#define DST_GC_MIN (HZ/10)
21#define DST_GC_INC (HZ/2)
22#define DST_GC_MAX (120*HZ)
23
24/* Each dst_entry has reference count and sits in some parent list(s).
25 * When it is removed from parent list, it is "freed" (dst_free).
26 * After this it enters dead state (dst->obsolete > 0) and if its refcnt
27 * is zero, it can be destroyed immediately, otherwise it is added
28 * to gc list and garbage collector periodically checks the refcnt.
29 */
30
31struct sk_buff;
32
fd2c3ef7 33struct dst_entry {
1e19e02c 34 struct rcu_head rcu_head;
1da177e4
LT
35 struct dst_entry *child;
36 struct net_device *dev;
62fa8a84
DM
37 struct dst_ops *ops;
38 unsigned long _metrics;
ecd98837 39 unsigned long expires;
f1dd9c37 40 struct dst_entry *path;
ecd98837 41 struct dst_entry *from;
def8b4fa 42#ifdef CONFIG_XFRM
1da177e4 43 struct xfrm_state *xfrm;
5635c10d
ED
44#else
45 void *__pad1;
def8b4fa 46#endif
7f95e188 47 int (*input)(struct sk_buff *);
ede2059d 48 int (*output)(struct net *net, struct sock *sk, struct sk_buff *skb);
1da177e4 49
5110effe 50 unsigned short flags;
f6b72b62
DM
51#define DST_HOST 0x0001
52#define DST_NOXFRM 0x0002
53#define DST_NOPOLICY 0x0004
54#define DST_NOHASH 0x0008
55#define DST_NOCACHE 0x0010
56#define DST_NOCOUNT 0x0020
e90c1483
HFS
57#define DST_FAKE_RTABLE 0x0040
58#define DST_XFRM_TUNNEL 0x0080
59#define DST_XFRM_QUEUE 0x0100
f38a9eb1 60#define DST_METADATA 0x0200
f6b72b62 61
62fa8a84 62 short error;
f5b0a874
DM
63
64 /* A non-zero value of dst->obsolete forces by-hand validation
65 * of the route entry. Positive values are set by the generic
66 * dst layer to indicate that the entry has been forcefully
67 * destroyed.
68 *
69 * Negative values are used by the implementation layer code to
70 * force invocation of the dst_ops->check() method.
71 */
62fa8a84 72 short obsolete;
f5b0a874
DM
73#define DST_OBSOLETE_NONE 0
74#define DST_OBSOLETE_DEAD 2
75#define DST_OBSOLETE_FORCE_CHK -1
ceb33206 76#define DST_OBSOLETE_KILL -2
62fa8a84
DM
77 unsigned short header_len; /* more space at head required */
78 unsigned short trailer_len; /* space to reserve at tail */
51ce8bd4
JA
79 unsigned short __pad3;
80
c7066f70 81#ifdef CONFIG_IP_ROUTE_CLASSID
f1dd9c37 82 __u32 tclassid;
5635c10d
ED
83#else
84 __u32 __pad2;
f1dd9c37
ZY
85#endif
86
751a587a 87#ifdef CONFIG_64BIT
5635c10d
ED
88 /*
89 * Align __refcnt to a 64 bytes alignment
90 * (L1_CACHE_SIZE would be too much)
91 */
0868e253 92 long __pad_to_align_refcnt[2];
5635c10d 93#endif
f1dd9c37
ZY
94 /*
95 * __refcnt wants to be on a different cache line from
96 * input/output/ops or performance tanks badly
97 */
1e19e02c
ED
98 atomic_t __refcnt; /* client references */
99 int __use;
f1dd9c37 100 unsigned long lastuse;
751a587a 101 struct lwtunnel_state *lwtstate;
1e19e02c 102 union {
fc766e4c
ED
103 struct dst_entry *next;
104 struct rtable __rcu *rt_next;
105 struct rt6_info *rt6_next;
106 struct dn_route __rcu *dn_next;
1e19e02c 107 };
1da177e4
LT
108};
109
a4023dd0 110u32 *dst_cow_metrics_generic(struct dst_entry *dst, unsigned long old);
a37e6e34 111extern const u32 dst_default_metrics[];
62fa8a84 112
e5fd387a 113#define DST_METRICS_READ_ONLY 0x1UL
e5fd387a 114#define DST_METRICS_FLAGS 0x3UL
62fa8a84 115#define __DST_METRICS_PTR(Y) \
e5fd387a 116 ((u32 *)((Y) & ~DST_METRICS_FLAGS))
62fa8a84
DM
117#define DST_METRICS_PTR(X) __DST_METRICS_PTR((X)->_metrics)
118
119static inline bool dst_metrics_read_only(const struct dst_entry *dst)
120{
121 return dst->_metrics & DST_METRICS_READ_ONLY;
122}
123
a4023dd0 124void __dst_destroy_metrics_generic(struct dst_entry *dst, unsigned long old);
62fa8a84
DM
125
126static inline void dst_destroy_metrics_generic(struct dst_entry *dst)
127{
128 unsigned long val = dst->_metrics;
129 if (!(val & DST_METRICS_READ_ONLY))
130 __dst_destroy_metrics_generic(dst, val);
131}
132
133static inline u32 *dst_metrics_write_ptr(struct dst_entry *dst)
134{
135 unsigned long p = dst->_metrics;
136
1f37070d
SH
137 BUG_ON(!p);
138
62fa8a84
DM
139 if (p & DST_METRICS_READ_ONLY)
140 return dst->ops->cow_metrics(dst, p);
141 return __DST_METRICS_PTR(p);
142}
143
144/* This may only be invoked before the entry has reached global
145 * visibility.
146 */
147static inline void dst_init_metrics(struct dst_entry *dst,
148 const u32 *src_metrics,
149 bool read_only)
150{
151 dst->_metrics = ((unsigned long) src_metrics) |
152 (read_only ? DST_METRICS_READ_ONLY : 0);
153}
154
155static inline void dst_copy_metrics(struct dst_entry *dest, const struct dst_entry *src)
156{
157 u32 *dst_metrics = dst_metrics_write_ptr(dest);
158
159 if (dst_metrics) {
160 u32 *src_metrics = DST_METRICS_PTR(src);
161
162 memcpy(dst_metrics, src_metrics, RTAX_MAX * sizeof(u32));
163 }
164}
165
166static inline u32 *dst_metrics_ptr(struct dst_entry *dst)
167{
168 return DST_METRICS_PTR(dst);
169}
170
1da177e4 171static inline u32
5170ae82 172dst_metric_raw(const struct dst_entry *dst, const int metric)
1da177e4 173{
62fa8a84
DM
174 u32 *p = DST_METRICS_PTR(dst);
175
176 return p[metric-1];
defb3519
DM
177}
178
5170ae82
DM
179static inline u32
180dst_metric(const struct dst_entry *dst, const int metric)
181{
0dbaee3b 182 WARN_ON_ONCE(metric == RTAX_HOPLIMIT ||
d33e4553
DM
183 metric == RTAX_ADVMSS ||
184 metric == RTAX_MTU);
5170ae82
DM
185 return dst_metric_raw(dst, metric);
186}
187
0dbaee3b
DM
188static inline u32
189dst_metric_advmss(const struct dst_entry *dst)
190{
191 u32 advmss = dst_metric_raw(dst, RTAX_ADVMSS);
192
193 if (!advmss)
194 advmss = dst->ops->default_advmss(dst);
195
196 return advmss;
197}
198
defb3519
DM
199static inline void dst_metric_set(struct dst_entry *dst, int metric, u32 val)
200{
62fa8a84 201 u32 *p = dst_metrics_write_ptr(dst);
defb3519 202
62fa8a84
DM
203 if (p)
204 p[metric-1] = val;
1da177e4
LT
205}
206
c3a8d947
DB
207/* Kernel-internal feature bits that are unallocated in user space. */
208#define DST_FEATURE_ECN_CA (1 << 31)
209
210#define DST_FEATURE_MASK (DST_FEATURE_ECN_CA)
211#define DST_FEATURE_ECN_MASK (DST_FEATURE_ECN_CA | RTAX_FEATURE_ECN)
212
0c3adfb8
GBY
213static inline u32
214dst_feature(const struct dst_entry *dst, u32 feature)
215{
bb5b7c11 216 return dst_metric(dst, RTAX_FEATURES) & feature;
0c3adfb8
GBY
217}
218
1da177e4
LT
219static inline u32 dst_mtu(const struct dst_entry *dst)
220{
618f9bc7 221 return dst->ops->mtu(dst);
1da177e4
LT
222}
223
c1e20f7c
SH
224/* RTT metrics are stored in milliseconds for user ABI, but used as jiffies */
225static inline unsigned long dst_metric_rtt(const struct dst_entry *dst, int metric)
226{
227 return msecs_to_jiffies(dst_metric(dst, metric));
228}
229
1da177e4
LT
230static inline u32
231dst_allfrag(const struct dst_entry *dst)
232{
0c3adfb8 233 int ret = dst_feature(dst, RTAX_FEATURE_ALLFRAG);
1da177e4
LT
234 return ret;
235}
236
237static inline int
d33e4553 238dst_metric_locked(const struct dst_entry *dst, int metric)
1da177e4
LT
239{
240 return dst_metric(dst, RTAX_LOCK) & (1<<metric);
241}
242
7f95e188 243static inline void dst_hold(struct dst_entry *dst)
1da177e4 244{
5635c10d
ED
245 /*
246 * If your kernel compilation stops here, please check
247 * __pad_to_align_refcnt declaration in struct dst_entry
248 */
249 BUILD_BUG_ON(offsetof(struct dst_entry, __refcnt) & 63);
1da177e4
LT
250 atomic_inc(&dst->__refcnt);
251}
252
03f49f34
PE
253static inline void dst_use(struct dst_entry *dst, unsigned long time)
254{
255 dst_hold(dst);
256 dst->__use++;
257 dst->lastuse = time;
258}
259
7fee226a
ED
260static inline void dst_use_noref(struct dst_entry *dst, unsigned long time)
261{
262 dst->__use++;
263 dst->lastuse = time;
264}
265
7f95e188 266static inline struct dst_entry *dst_clone(struct dst_entry *dst)
1da177e4
LT
267{
268 if (dst)
269 atomic_inc(&dst->__refcnt);
270 return dst;
271}
272
a4023dd0 273void dst_release(struct dst_entry *dst);
7fee226a
ED
274
275static inline void refdst_drop(unsigned long refdst)
276{
277 if (!(refdst & SKB_DST_NOREF))
278 dst_release((struct dst_entry *)(refdst & SKB_DST_PTRMASK));
279}
280
281/**
282 * skb_dst_drop - drops skb dst
283 * @skb: buffer
284 *
285 * Drops dst reference count if a reference was taken.
286 */
adf30907
ED
287static inline void skb_dst_drop(struct sk_buff *skb)
288{
7fee226a
ED
289 if (skb->_skb_refdst) {
290 refdst_drop(skb->_skb_refdst);
291 skb->_skb_refdst = 0UL;
292 }
293}
294
e79e2595 295static inline void __skb_dst_copy(struct sk_buff *nskb, unsigned long refdst)
7fee226a 296{
e79e2595 297 nskb->_skb_refdst = refdst;
7fee226a
ED
298 if (!(nskb->_skb_refdst & SKB_DST_NOREF))
299 dst_clone(skb_dst(nskb));
300}
301
e79e2595
JS
302static inline void skb_dst_copy(struct sk_buff *nskb, const struct sk_buff *oskb)
303{
304 __skb_dst_copy(nskb, oskb->_skb_refdst);
305}
306
7fee226a
ED
307/**
308 * skb_dst_force - makes sure skb dst is refcounted
309 * @skb: buffer
310 *
311 * If dst is not yet refcounted, let's do it
312 */
313static inline void skb_dst_force(struct sk_buff *skb)
314{
315 if (skb_dst_is_noref(skb)) {
316 WARN_ON(!rcu_read_lock_held());
317 skb->_skb_refdst &= ~SKB_DST_NOREF;
318 dst_clone(skb_dst(skb));
319 }
adf30907 320}
1da177e4 321
5037e9ef
ED
322/**
323 * dst_hold_safe - Take a reference on a dst if possible
324 * @dst: pointer to dst entry
325 *
326 * This helper returns false if it could not safely
327 * take a reference on a dst.
328 */
329static inline bool dst_hold_safe(struct dst_entry *dst)
330{
331 if (dst->flags & DST_NOCACHE)
332 return atomic_inc_not_zero(&dst->__refcnt);
333 dst_hold(dst);
334 return true;
335}
336
337/**
338 * skb_dst_force_safe - makes sure skb dst is refcounted
339 * @skb: buffer
340 *
341 * If dst is not yet refcounted and not destroyed, grab a ref on it.
342 */
343static inline void skb_dst_force_safe(struct sk_buff *skb)
344{
345 if (skb_dst_is_noref(skb)) {
346 struct dst_entry *dst = skb_dst(skb);
347
348 if (!dst_hold_safe(dst))
349 dst = NULL;
350
351 skb->_skb_refdst = (unsigned long)dst;
352 }
353}
354
d19d56dd 355
290b895e
ED
356/**
357 * __skb_tunnel_rx - prepare skb for rx reinsert
358 * @skb: buffer
359 * @dev: tunnel device
ea23192e 360 * @net: netns for packet i/o
290b895e
ED
361 *
362 * After decapsulation, packet is going to re-enter (netif_rx()) our stack,
363 * so make some cleanups. (no accounting done)
364 */
ea23192e
ND
365static inline void __skb_tunnel_rx(struct sk_buff *skb, struct net_device *dev,
366 struct net *net)
290b895e
ED
367{
368 skb->dev = dev;
bdeab991
TH
369
370 /*
7539fadc 371 * Clear hash so that we can recalulate the hash for the
bdeab991
TH
372 * encapsulated packet, unless we have already determine the hash
373 * over the L4 4-tuple.
374 */
7539fadc 375 skb_clear_hash_if_not_l4(skb);
290b895e 376 skb_set_queue_mapping(skb, 0);
ea23192e 377 skb_scrub_packet(skb, !net_eq(net, dev_net(dev)));
290b895e
ED
378}
379
d19d56dd
ED
380/**
381 * skb_tunnel_rx - prepare skb for rx reinsert
382 * @skb: buffer
383 * @dev: tunnel device
384 *
385 * After decapsulation, packet is going to re-enter (netif_rx()) our stack,
386 * so make some cleanups, and perform accounting.
290b895e 387 * Note: this accounting is not SMP safe.
d19d56dd 388 */
ea23192e
ND
389static inline void skb_tunnel_rx(struct sk_buff *skb, struct net_device *dev,
390 struct net *net)
d19d56dd 391{
d19d56dd
ED
392 /* TODO : stats should be SMP safe */
393 dev->stats.rx_packets++;
394 dev->stats.rx_bytes += skb->len;
ea23192e 395 __skb_tunnel_rx(skb, dev, net);
d19d56dd
ED
396}
397
808c1b69
DB
398static inline u32 dst_tclassid(const struct sk_buff *skb)
399{
400#ifdef CONFIG_IP_ROUTE_CLASSID
401 const struct dst_entry *dst;
402
403 dst = skb_dst(skb);
404 if (dst)
405 return dst->tclassid;
406#endif
407 return 0;
408}
409
ede2059d 410int dst_discard_out(struct net *net, struct sock *sk, struct sk_buff *skb);
aad88724
ED
411static inline int dst_discard(struct sk_buff *skb)
412{
ede2059d 413 return dst_discard_out(&init_net, skb->sk, skb);
aad88724 414}
a4023dd0
JP
415void *dst_alloc(struct dst_ops *ops, struct net_device *dev, int initial_ref,
416 int initial_obsolete, unsigned short flags);
f38a9eb1
TG
417void dst_init(struct dst_entry *dst, struct dst_ops *ops,
418 struct net_device *dev, int initial_ref, int initial_obsolete,
419 unsigned short flags);
a4023dd0
JP
420void __dst_free(struct dst_entry *dst);
421struct dst_entry *dst_destroy(struct dst_entry *dst);
1da177e4 422
7f95e188 423static inline void dst_free(struct dst_entry *dst)
1da177e4 424{
f5b0a874 425 if (dst->obsolete > 0)
1da177e4
LT
426 return;
427 if (!atomic_read(&dst->__refcnt)) {
428 dst = dst_destroy(dst);
429 if (!dst)
430 return;
431 }
432 __dst_free(dst);
433}
434
435static inline void dst_rcu_free(struct rcu_head *head)
436{
437 struct dst_entry *dst = container_of(head, struct dst_entry, rcu_head);
438 dst_free(dst);
439}
440
441static inline void dst_confirm(struct dst_entry *dst)
442{
5110effe 443}
f2c31e32 444
d3aaeb38
DM
445static inline struct neighbour *dst_neigh_lookup(const struct dst_entry *dst, const void *daddr)
446{
aaa0c23c
ZZ
447 struct neighbour *n = dst->ops->neigh_lookup(dst, NULL, daddr);
448 return IS_ERR(n) ? NULL : n;
f894cbf8
DM
449}
450
451static inline struct neighbour *dst_neigh_lookup_skb(const struct dst_entry *dst,
452 struct sk_buff *skb)
453{
aaa0c23c
ZZ
454 struct neighbour *n = dst->ops->neigh_lookup(dst, skb, NULL);
455 return IS_ERR(n) ? NULL : n;
d3aaeb38
DM
456}
457
63fca65d
JA
458static inline void dst_confirm_neigh(const struct dst_entry *dst,
459 const void *daddr)
460{
461 if (dst->ops->confirm_neigh)
462 dst->ops->confirm_neigh(dst, daddr);
463}
464
1da177e4
LT
465static inline void dst_link_failure(struct sk_buff *skb)
466{
adf30907 467 struct dst_entry *dst = skb_dst(skb);
1da177e4
LT
468 if (dst && dst->ops && dst->ops->link_failure)
469 dst->ops->link_failure(skb);
470}
471
472static inline void dst_set_expires(struct dst_entry *dst, int timeout)
473{
474 unsigned long expires = jiffies + timeout;
475
476 if (expires == 0)
477 expires = 1;
478
479 if (dst->expires == 0 || time_before(expires, dst->expires))
480 dst->expires = expires;
481}
482
483/* Output packet to network from transport. */
13206b6b 484static inline int dst_output(struct net *net, struct sock *sk, struct sk_buff *skb)
aad88724 485{
ede2059d 486 return skb_dst(skb)->output(net, sk, skb);
aad88724 487}
1da177e4
LT
488
489/* Input packet from network to transport. */
490static inline int dst_input(struct sk_buff *skb)
491{
adf30907 492 return skb_dst(skb)->input(skb);
1da177e4
LT
493}
494
495static inline struct dst_entry *dst_check(struct dst_entry *dst, u32 cookie)
496{
497 if (dst->obsolete)
498 dst = dst->ops->check(dst, cookie);
499 return dst;
500}
501
f38a9eb1 502void dst_subsys_init(void);
1da177e4 503
815f4e57
HX
504/* Flags for xfrm_lookup flags argument. */
505enum {
80c0bc9e 506 XFRM_LOOKUP_ICMP = 1 << 0,
b8c203b2 507 XFRM_LOOKUP_QUEUE = 1 << 1,
ac37e251 508 XFRM_LOOKUP_KEEP_DST_REF = 1 << 2,
815f4e57
HX
509};
510
1da177e4
LT
511struct flowi;
512#ifndef CONFIG_XFRM
452edd59
DM
513static inline struct dst_entry *xfrm_lookup(struct net *net,
514 struct dst_entry *dst_orig,
6f9c9615
ED
515 const struct flowi *fl,
516 const struct sock *sk,
452edd59 517 int flags)
1da177e4 518{
452edd59 519 return dst_orig;
f92ee619
SK
520}
521
522static inline struct dst_entry *xfrm_lookup_route(struct net *net,
523 struct dst_entry *dst_orig,
524 const struct flowi *fl,
6f9c9615 525 const struct sock *sk,
f92ee619
SK
526 int flags)
527{
528 return dst_orig;
529}
e87b3998
VY
530
531static inline struct xfrm_state *dst_xfrm(const struct dst_entry *dst)
532{
533 return NULL;
534}
535
1da177e4 536#else
a4023dd0 537struct dst_entry *xfrm_lookup(struct net *net, struct dst_entry *dst_orig,
6f9c9615 538 const struct flowi *fl, const struct sock *sk,
a4023dd0 539 int flags);
e87b3998 540
f92ee619 541struct dst_entry *xfrm_lookup_route(struct net *net, struct dst_entry *dst_orig,
6f9c9615 542 const struct flowi *fl, const struct sock *sk,
f92ee619
SK
543 int flags);
544
e87b3998
VY
545/* skb attached with this dst needs transformation if dst->xfrm is valid */
546static inline struct xfrm_state *dst_xfrm(const struct dst_entry *dst)
547{
548 return dst->xfrm;
549}
1da177e4 550#endif
1da177e4
LT
551
552#endif /* _NET_DST_H */