2 * net/dst.h Protocol independent destination cache definitions.
4 * Authors: Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
11 #include <net/dst_ops.h>
12 #include <linux/netdevice.h>
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>
19 #define DST_GC_MIN (HZ/10)
20 #define DST_GC_INC (HZ/2)
21 #define DST_GC_MAX (120*HZ)
23 /* Each dst_entry has reference count and sits in some parent list(s).
24 * When it is removed from parent list, it is "freed" (dst_free).
25 * After this it enters dead state (dst->obsolete > 0) and if its refcnt
26 * is zero, it can be destroyed immediately, otherwise it is added
27 * to gc list and garbage collector periodically checks the refcnt.
33 struct rcu_head rcu_head;
34 struct dst_entry *child;
35 struct net_device *dev;
37 unsigned long _metrics;
38 unsigned long expires;
39 struct dst_entry *path;
40 struct neighbour __rcu *_neighbour;
42 struct xfrm_state *xfrm;
46 int (*input)(struct sk_buff*);
47 int (*output)(struct sk_buff*);
50 #define DST_HOST 0x0001
51 #define DST_NOXFRM 0x0002
52 #define DST_NOPOLICY 0x0004
53 #define DST_NOHASH 0x0008
54 #define DST_NOCACHE 0x0010
55 #define DST_NOCOUNT 0x0020
56 #define DST_NOPEER 0x0040
57 #define DST_FAKE_RTABLE 0x0080
58 #define DST_XFRM_TUNNEL 0x0100
62 unsigned short header_len; /* more space at head required */
63 unsigned short trailer_len; /* space to reserve at tail */
64 #ifdef CONFIG_IP_ROUTE_CLASSID
71 * Align __refcnt to a 64 bytes alignment
72 * (L1_CACHE_SIZE would be too much)
75 long __pad_to_align_refcnt[2];
78 * __refcnt wants to be on a different cache line from
79 * input/output/ops or performance tanks badly
81 atomic_t __refcnt; /* client references */
83 unsigned long lastuse;
85 struct dst_entry *next;
86 struct rtable __rcu *rt_next;
87 struct rt6_info *rt6_next;
88 struct dn_route __rcu *dn_next;
92 static inline struct neighbour *dst_get_neighbour(struct dst_entry *dst)
94 return rcu_dereference(dst->_neighbour);
97 static inline struct neighbour *dst_get_neighbour_raw(struct dst_entry *dst)
99 return rcu_dereference_raw(dst->_neighbour);
102 static inline void dst_set_neighbour(struct dst_entry *dst, struct neighbour *neigh)
104 rcu_assign_pointer(dst->_neighbour, neigh);
107 extern u32 *dst_cow_metrics_generic(struct dst_entry *dst, unsigned long old);
108 extern const u32 dst_default_metrics[RTAX_MAX];
110 #define DST_METRICS_READ_ONLY 0x1UL
111 #define __DST_METRICS_PTR(Y) \
112 ((u32 *)((Y) & ~DST_METRICS_READ_ONLY))
113 #define DST_METRICS_PTR(X) __DST_METRICS_PTR((X)->_metrics)
115 static inline bool dst_metrics_read_only(const struct dst_entry *dst)
117 return dst->_metrics & DST_METRICS_READ_ONLY;
120 extern void __dst_destroy_metrics_generic(struct dst_entry *dst, unsigned long old);
122 static inline void dst_destroy_metrics_generic(struct dst_entry *dst)
124 unsigned long val = dst->_metrics;
125 if (!(val & DST_METRICS_READ_ONLY))
126 __dst_destroy_metrics_generic(dst, val);
129 static inline u32 *dst_metrics_write_ptr(struct dst_entry *dst)
131 unsigned long p = dst->_metrics;
135 if (p & DST_METRICS_READ_ONLY)
136 return dst->ops->cow_metrics(dst, p);
137 return __DST_METRICS_PTR(p);
140 /* This may only be invoked before the entry has reached global
143 static inline void dst_init_metrics(struct dst_entry *dst,
144 const u32 *src_metrics,
147 dst->_metrics = ((unsigned long) src_metrics) |
148 (read_only ? DST_METRICS_READ_ONLY : 0);
151 static inline void dst_copy_metrics(struct dst_entry *dest, const struct dst_entry *src)
153 u32 *dst_metrics = dst_metrics_write_ptr(dest);
156 u32 *src_metrics = DST_METRICS_PTR(src);
158 memcpy(dst_metrics, src_metrics, RTAX_MAX * sizeof(u32));
162 static inline u32 *dst_metrics_ptr(struct dst_entry *dst)
164 return DST_METRICS_PTR(dst);
168 dst_metric_raw(const struct dst_entry *dst, const int metric)
170 u32 *p = DST_METRICS_PTR(dst);
176 dst_metric(const struct dst_entry *dst, const int metric)
178 WARN_ON_ONCE(metric == RTAX_HOPLIMIT ||
179 metric == RTAX_ADVMSS ||
181 return dst_metric_raw(dst, metric);
185 dst_metric_advmss(const struct dst_entry *dst)
187 u32 advmss = dst_metric_raw(dst, RTAX_ADVMSS);
190 advmss = dst->ops->default_advmss(dst);
195 static inline void dst_metric_set(struct dst_entry *dst, int metric, u32 val)
197 u32 *p = dst_metrics_write_ptr(dst);
204 dst_feature(const struct dst_entry *dst, u32 feature)
206 return dst_metric(dst, RTAX_FEATURES) & feature;
209 static inline u32 dst_mtu(const struct dst_entry *dst)
211 return dst->ops->mtu(dst);
214 /* RTT metrics are stored in milliseconds for user ABI, but used as jiffies */
215 static inline unsigned long dst_metric_rtt(const struct dst_entry *dst, int metric)
217 return msecs_to_jiffies(dst_metric(dst, metric));
220 static inline void set_dst_metric_rtt(struct dst_entry *dst, int metric,
223 dst_metric_set(dst, metric, jiffies_to_msecs(rtt));
227 dst_allfrag(const struct dst_entry *dst)
229 int ret = dst_feature(dst, RTAX_FEATURE_ALLFRAG);
234 dst_metric_locked(const struct dst_entry *dst, int metric)
236 return dst_metric(dst, RTAX_LOCK) & (1<<metric);
239 static inline void dst_hold(struct dst_entry * dst)
242 * If your kernel compilation stops here, please check
243 * __pad_to_align_refcnt declaration in struct dst_entry
245 BUILD_BUG_ON(offsetof(struct dst_entry, __refcnt) & 63);
246 atomic_inc(&dst->__refcnt);
249 static inline void dst_use(struct dst_entry *dst, unsigned long time)
256 static inline void dst_use_noref(struct dst_entry *dst, unsigned long time)
263 struct dst_entry * dst_clone(struct dst_entry * dst)
266 atomic_inc(&dst->__refcnt);
270 extern void dst_release(struct dst_entry *dst);
272 static inline void refdst_drop(unsigned long refdst)
274 if (!(refdst & SKB_DST_NOREF))
275 dst_release((struct dst_entry *)(refdst & SKB_DST_PTRMASK));
279 * skb_dst_drop - drops skb dst
282 * Drops dst reference count if a reference was taken.
284 static inline void skb_dst_drop(struct sk_buff *skb)
286 if (skb->_skb_refdst) {
287 refdst_drop(skb->_skb_refdst);
288 skb->_skb_refdst = 0UL;
292 static inline void skb_dst_copy(struct sk_buff *nskb, const struct sk_buff *oskb)
294 nskb->_skb_refdst = oskb->_skb_refdst;
295 if (!(nskb->_skb_refdst & SKB_DST_NOREF))
296 dst_clone(skb_dst(nskb));
300 * skb_dst_force - makes sure skb dst is refcounted
303 * If dst is not yet refcounted, let's do it
305 static inline void skb_dst_force(struct sk_buff *skb)
307 if (skb_dst_is_noref(skb)) {
308 WARN_ON(!rcu_read_lock_held());
309 skb->_skb_refdst &= ~SKB_DST_NOREF;
310 dst_clone(skb_dst(skb));
316 * __skb_tunnel_rx - prepare skb for rx reinsert
318 * @dev: tunnel device
320 * After decapsulation, packet is going to re-enter (netif_rx()) our stack,
321 * so make some cleanups. (no accounting done)
323 static inline void __skb_tunnel_rx(struct sk_buff *skb, struct net_device *dev)
328 * Clear rxhash so that we can recalulate the hash for the
329 * encapsulated packet, unless we have already determine the hash
330 * over the L4 4-tuple.
334 skb_set_queue_mapping(skb, 0);
340 * skb_tunnel_rx - prepare skb for rx reinsert
342 * @dev: tunnel device
344 * After decapsulation, packet is going to re-enter (netif_rx()) our stack,
345 * so make some cleanups, and perform accounting.
346 * Note: this accounting is not SMP safe.
348 static inline void skb_tunnel_rx(struct sk_buff *skb, struct net_device *dev)
350 /* TODO : stats should be SMP safe */
351 dev->stats.rx_packets++;
352 dev->stats.rx_bytes += skb->len;
353 __skb_tunnel_rx(skb, dev);
356 /* Children define the path of the packet through the
357 * Linux networking. Thus, destinations are stackable.
360 static inline struct dst_entry *skb_dst_pop(struct sk_buff *skb)
362 struct dst_entry *child = dst_clone(skb_dst(skb)->child);
368 extern int dst_discard(struct sk_buff *skb);
369 extern void *dst_alloc(struct dst_ops * ops, struct net_device *dev,
370 int initial_ref, int initial_obsolete, int flags);
371 extern void __dst_free(struct dst_entry * dst);
372 extern struct dst_entry *dst_destroy(struct dst_entry * dst);
374 static inline void dst_free(struct dst_entry * dst)
376 if (dst->obsolete > 1)
378 if (!atomic_read(&dst->__refcnt)) {
379 dst = dst_destroy(dst);
386 static inline void dst_rcu_free(struct rcu_head *head)
388 struct dst_entry *dst = container_of(head, struct dst_entry, rcu_head);
392 static inline void dst_confirm(struct dst_entry *dst)
398 n = dst_get_neighbour(dst);
404 static inline struct neighbour *dst_neigh_lookup(const struct dst_entry *dst, const void *daddr)
406 return dst->ops->neigh_lookup(dst, daddr);
409 static inline void dst_link_failure(struct sk_buff *skb)
411 struct dst_entry *dst = skb_dst(skb);
412 if (dst && dst->ops && dst->ops->link_failure)
413 dst->ops->link_failure(skb);
416 static inline void dst_set_expires(struct dst_entry *dst, int timeout)
418 unsigned long expires = jiffies + timeout;
423 if (dst->expires == 0 || time_before(expires, dst->expires))
424 dst->expires = expires;
427 /* Output packet to network from transport. */
428 static inline int dst_output(struct sk_buff *skb)
430 return skb_dst(skb)->output(skb);
433 /* Input packet from network to transport. */
434 static inline int dst_input(struct sk_buff *skb)
436 return skb_dst(skb)->input(skb);
439 static inline struct dst_entry *dst_check(struct dst_entry *dst, u32 cookie)
442 dst = dst->ops->check(dst, cookie);
446 extern void dst_init(void);
448 /* Flags for xfrm_lookup flags argument. */
450 XFRM_LOOKUP_ICMP = 1 << 0,
455 static inline struct dst_entry *xfrm_lookup(struct net *net,
456 struct dst_entry *dst_orig,
457 const struct flowi *fl, struct sock *sk,
463 static inline struct xfrm_state *dst_xfrm(const struct dst_entry *dst)
469 extern struct dst_entry *xfrm_lookup(struct net *net, struct dst_entry *dst_orig,
470 const struct flowi *fl, struct sock *sk,
473 /* skb attached with this dst needs transformation if dst->xfrm is valid */
474 static inline struct xfrm_state *dst_xfrm(const struct dst_entry *dst)
480 #endif /* _NET_DST_H */