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/bug.h>
16 #include <linux/jiffies.h>
17 #include <net/neighbour.h>
18 #include <asm/processor.h>
20 #define DST_GC_MIN (HZ/10)
21 #define DST_GC_INC (HZ/2)
22 #define DST_GC_MAX (120*HZ)
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.
34 struct rcu_head rcu_head;
35 struct dst_entry *child;
36 struct net_device *dev;
38 unsigned long _metrics;
40 unsigned long expires;
41 /* point to where the dst_entry copied from */
42 struct dst_entry *from;
44 struct dst_entry *path;
47 struct xfrm_state *xfrm;
51 int (*input)(struct sk_buff *);
52 int (*output)(struct sk_buff *);
55 #define DST_HOST 0x0001
56 #define DST_NOXFRM 0x0002
57 #define DST_NOPOLICY 0x0004
58 #define DST_NOHASH 0x0008
59 #define DST_NOCACHE 0x0010
60 #define DST_NOCOUNT 0x0020
61 #define DST_NOPEER 0x0040
62 #define DST_FAKE_RTABLE 0x0080
63 #define DST_XFRM_TUNNEL 0x0100
65 unsigned short pending_confirm;
69 /* A non-zero value of dst->obsolete forces by-hand validation
70 * of the route entry. Positive values are set by the generic
71 * dst layer to indicate that the entry has been forcefully
74 * Negative values are used by the implementation layer code to
75 * force invocation of the dst_ops->check() method.
78 #define DST_OBSOLETE_NONE 0
79 #define DST_OBSOLETE_DEAD 2
80 #define DST_OBSOLETE_FORCE_CHK -1
81 unsigned short header_len; /* more space at head required */
82 unsigned short trailer_len; /* space to reserve at tail */
83 #ifdef CONFIG_IP_ROUTE_CLASSID
90 * Align __refcnt to a 64 bytes alignment
91 * (L1_CACHE_SIZE would be too much)
94 long __pad_to_align_refcnt[2];
97 * __refcnt wants to be on a different cache line from
98 * input/output/ops or performance tanks badly
100 atomic_t __refcnt; /* client references */
102 unsigned long lastuse;
104 struct dst_entry *next;
105 struct rtable __rcu *rt_next;
106 struct rt6_info *rt6_next;
107 struct dn_route __rcu *dn_next;
111 extern u32 *dst_cow_metrics_generic(struct dst_entry *dst, unsigned long old);
112 extern const u32 dst_default_metrics[RTAX_MAX];
114 #define DST_METRICS_READ_ONLY 0x1UL
115 #define __DST_METRICS_PTR(Y) \
116 ((u32 *)((Y) & ~DST_METRICS_READ_ONLY))
117 #define DST_METRICS_PTR(X) __DST_METRICS_PTR((X)->_metrics)
119 static inline bool dst_metrics_read_only(const struct dst_entry *dst)
121 return dst->_metrics & DST_METRICS_READ_ONLY;
124 extern void __dst_destroy_metrics_generic(struct dst_entry *dst, unsigned long old);
126 static inline void dst_destroy_metrics_generic(struct dst_entry *dst)
128 unsigned long val = dst->_metrics;
129 if (!(val & DST_METRICS_READ_ONLY))
130 __dst_destroy_metrics_generic(dst, val);
133 static inline u32 *dst_metrics_write_ptr(struct dst_entry *dst)
135 unsigned long p = dst->_metrics;
139 if (p & DST_METRICS_READ_ONLY)
140 return dst->ops->cow_metrics(dst, p);
141 return __DST_METRICS_PTR(p);
144 /* This may only be invoked before the entry has reached global
147 static inline void dst_init_metrics(struct dst_entry *dst,
148 const u32 *src_metrics,
151 dst->_metrics = ((unsigned long) src_metrics) |
152 (read_only ? DST_METRICS_READ_ONLY : 0);
155 static inline void dst_copy_metrics(struct dst_entry *dest, const struct dst_entry *src)
157 u32 *dst_metrics = dst_metrics_write_ptr(dest);
160 u32 *src_metrics = DST_METRICS_PTR(src);
162 memcpy(dst_metrics, src_metrics, RTAX_MAX * sizeof(u32));
166 static inline u32 *dst_metrics_ptr(struct dst_entry *dst)
168 return DST_METRICS_PTR(dst);
172 dst_metric_raw(const struct dst_entry *dst, const int metric)
174 u32 *p = DST_METRICS_PTR(dst);
180 dst_metric(const struct dst_entry *dst, const int metric)
182 WARN_ON_ONCE(metric == RTAX_HOPLIMIT ||
183 metric == RTAX_ADVMSS ||
185 return dst_metric_raw(dst, metric);
189 dst_metric_advmss(const struct dst_entry *dst)
191 u32 advmss = dst_metric_raw(dst, RTAX_ADVMSS);
194 advmss = dst->ops->default_advmss(dst);
199 static inline void dst_metric_set(struct dst_entry *dst, int metric, u32 val)
201 u32 *p = dst_metrics_write_ptr(dst);
208 dst_feature(const struct dst_entry *dst, u32 feature)
210 return dst_metric(dst, RTAX_FEATURES) & feature;
213 static inline u32 dst_mtu(const struct dst_entry *dst)
215 return dst->ops->mtu(dst);
218 /* RTT metrics are stored in milliseconds for user ABI, but used as jiffies */
219 static inline unsigned long dst_metric_rtt(const struct dst_entry *dst, int metric)
221 return msecs_to_jiffies(dst_metric(dst, metric));
225 dst_allfrag(const struct dst_entry *dst)
227 int ret = dst_feature(dst, RTAX_FEATURE_ALLFRAG);
232 dst_metric_locked(const struct dst_entry *dst, int metric)
234 return dst_metric(dst, RTAX_LOCK) & (1<<metric);
237 static inline void dst_hold(struct dst_entry *dst)
240 * If your kernel compilation stops here, please check
241 * __pad_to_align_refcnt declaration in struct dst_entry
243 BUILD_BUG_ON(offsetof(struct dst_entry, __refcnt) & 63);
244 atomic_inc(&dst->__refcnt);
247 static inline void dst_use(struct dst_entry *dst, unsigned long time)
254 static inline void dst_use_noref(struct dst_entry *dst, unsigned long time)
260 static inline struct dst_entry *dst_clone(struct dst_entry *dst)
263 atomic_inc(&dst->__refcnt);
267 extern void dst_release(struct dst_entry *dst);
269 static inline void refdst_drop(unsigned long refdst)
271 if (!(refdst & SKB_DST_NOREF))
272 dst_release((struct dst_entry *)(refdst & SKB_DST_PTRMASK));
276 * skb_dst_drop - drops skb dst
279 * Drops dst reference count if a reference was taken.
281 static inline void skb_dst_drop(struct sk_buff *skb)
283 if (skb->_skb_refdst) {
284 refdst_drop(skb->_skb_refdst);
285 skb->_skb_refdst = 0UL;
289 static inline void skb_dst_copy(struct sk_buff *nskb, const struct sk_buff *oskb)
291 nskb->_skb_refdst = oskb->_skb_refdst;
292 if (!(nskb->_skb_refdst & SKB_DST_NOREF))
293 dst_clone(skb_dst(nskb));
297 * skb_dst_force - makes sure skb dst is refcounted
300 * If dst is not yet refcounted, let's do it
302 static inline void skb_dst_force(struct sk_buff *skb)
304 if (skb_dst_is_noref(skb)) {
305 WARN_ON(!rcu_read_lock_held());
306 skb->_skb_refdst &= ~SKB_DST_NOREF;
307 dst_clone(skb_dst(skb));
313 * __skb_tunnel_rx - prepare skb for rx reinsert
315 * @dev: tunnel device
317 * After decapsulation, packet is going to re-enter (netif_rx()) our stack,
318 * so make some cleanups. (no accounting done)
320 static inline void __skb_tunnel_rx(struct sk_buff *skb, struct net_device *dev)
325 * Clear rxhash so that we can recalulate the hash for the
326 * encapsulated packet, unless we have already determine the hash
327 * over the L4 4-tuple.
331 skb_set_queue_mapping(skb, 0);
337 * skb_tunnel_rx - prepare skb for rx reinsert
339 * @dev: tunnel device
341 * After decapsulation, packet is going to re-enter (netif_rx()) our stack,
342 * so make some cleanups, and perform accounting.
343 * Note: this accounting is not SMP safe.
345 static inline void skb_tunnel_rx(struct sk_buff *skb, struct net_device *dev)
347 /* TODO : stats should be SMP safe */
348 dev->stats.rx_packets++;
349 dev->stats.rx_bytes += skb->len;
350 __skb_tunnel_rx(skb, dev);
353 /* Children define the path of the packet through the
354 * Linux networking. Thus, destinations are stackable.
357 static inline struct dst_entry *skb_dst_pop(struct sk_buff *skb)
359 struct dst_entry *child = dst_clone(skb_dst(skb)->child);
365 extern int dst_discard(struct sk_buff *skb);
366 extern void *dst_alloc(struct dst_ops *ops, struct net_device *dev,
367 int initial_ref, int initial_obsolete,
368 unsigned short flags);
369 extern void __dst_free(struct dst_entry *dst);
370 extern struct dst_entry *dst_destroy(struct dst_entry *dst);
372 static inline void dst_free(struct dst_entry *dst)
374 if (dst->obsolete > 0)
376 if (!atomic_read(&dst->__refcnt)) {
377 dst = dst_destroy(dst);
384 static inline void dst_rcu_free(struct rcu_head *head)
386 struct dst_entry *dst = container_of(head, struct dst_entry, rcu_head);
390 static inline void dst_confirm(struct dst_entry *dst)
392 dst->pending_confirm = 1;
395 static inline int dst_neigh_output(struct dst_entry *dst, struct neighbour *n,
400 if (unlikely(dst->pending_confirm)) {
401 n->confirmed = jiffies;
402 dst->pending_confirm = 0;
406 if ((n->nud_state & NUD_CONNECTED) && hh->hh_len)
407 return neigh_hh_output(hh, skb);
409 return n->output(n, skb);
412 static inline struct neighbour *dst_neigh_lookup(const struct dst_entry *dst, const void *daddr)
414 return dst->ops->neigh_lookup(dst, NULL, daddr);
417 static inline struct neighbour *dst_neigh_lookup_skb(const struct dst_entry *dst,
420 return dst->ops->neigh_lookup(dst, skb, NULL);
423 static inline void dst_link_failure(struct sk_buff *skb)
425 struct dst_entry *dst = skb_dst(skb);
426 if (dst && dst->ops && dst->ops->link_failure)
427 dst->ops->link_failure(skb);
430 static inline void dst_set_expires(struct dst_entry *dst, int timeout)
432 unsigned long expires = jiffies + timeout;
437 if (dst->expires == 0 || time_before(expires, dst->expires))
438 dst->expires = expires;
441 /* Output packet to network from transport. */
442 static inline int dst_output(struct sk_buff *skb)
444 return skb_dst(skb)->output(skb);
447 /* Input packet from network to transport. */
448 static inline int dst_input(struct sk_buff *skb)
450 return skb_dst(skb)->input(skb);
453 static inline struct dst_entry *dst_check(struct dst_entry *dst, u32 cookie)
456 dst = dst->ops->check(dst, cookie);
460 extern void dst_init(void);
462 /* Flags for xfrm_lookup flags argument. */
464 XFRM_LOOKUP_ICMP = 1 << 0,
469 static inline struct dst_entry *xfrm_lookup(struct net *net,
470 struct dst_entry *dst_orig,
471 const struct flowi *fl, struct sock *sk,
477 extern struct dst_entry *xfrm_lookup(struct net *net, struct dst_entry *dst_orig,
478 const struct flowi *fl, struct sock *sk,
482 #endif /* _NET_DST_H */