diff options
Diffstat (limited to 'include/net/dst.h')
| -rw-r--r-- | include/net/dst.h | 279 |
1 files changed, 279 insertions, 0 deletions
diff --git a/include/net/dst.h b/include/net/dst.h new file mode 100644 index 0000000..50adc91 --- /dev/null +++ b/include/net/dst.h @@ -0,0 +1,279 @@ +/* + * net/dst.h Protocol independent destination cache definitions. + * + * Authors: Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru> + * + */ + +#ifndef _NET_DST_H +#define _NET_DST_H + +#include <linux/config.h> +#include <linux/rtnetlink.h> +#include <linux/rcupdate.h> +#include <linux/jiffies.h> +#include <net/neighbour.h> +#include <asm/processor.h> + +/* + * 0 - no debugging messages + * 1 - rare events and bugs (default) + * 2 - trace mode. + */ +#define RT_CACHE_DEBUG 0 + +#define DST_GC_MIN (HZ/10) +#define DST_GC_INC (HZ/2) +#define DST_GC_MAX (120*HZ) + +/* Each dst_entry has reference count and sits in some parent list(s). + * When it is removed from parent list, it is "freed" (dst_free). + * After this it enters dead state (dst->obsolete > 0) and if its refcnt + * is zero, it can be destroyed immediately, otherwise it is added + * to gc list and garbage collector periodically checks the refcnt. + */ + +struct sk_buff; + +struct dst_entry +{ + struct dst_entry *next; + atomic_t __refcnt; /* client references */ + int __use; + struct dst_entry *child; + struct net_device *dev; + int obsolete; + int flags; +#define DST_HOST 1 +#define DST_NOXFRM 2 +#define DST_NOPOLICY 4 +#define DST_NOHASH 8 +#define DST_BALANCED 0x10 + unsigned long lastuse; + unsigned long expires; + + unsigned short header_len; /* more space at head required */ + unsigned short trailer_len; /* space to reserve at tail */ + + u32 metrics[RTAX_MAX]; + struct dst_entry *path; + + unsigned long rate_last; /* rate limiting for ICMP */ + unsigned long rate_tokens; + + int error; + + struct neighbour *neighbour; + struct hh_cache *hh; + struct xfrm_state *xfrm; + + int (*input)(struct sk_buff*); + int (*output)(struct sk_buff*); + +#ifdef CONFIG_NET_CLS_ROUTE + __u32 tclassid; +#endif + + struct dst_ops *ops; + struct rcu_head rcu_head; + + char info[0]; +}; + + +struct dst_ops +{ + unsigned short family; + unsigned short protocol; + unsigned gc_thresh; + + int (*gc)(void); + struct dst_entry * (*check)(struct dst_entry *, __u32 cookie); + void (*destroy)(struct dst_entry *); + void (*ifdown)(struct dst_entry *, + struct net_device *dev, int how); + struct dst_entry * (*negative_advice)(struct dst_entry *); + void (*link_failure)(struct sk_buff *); + void (*update_pmtu)(struct dst_entry *dst, u32 mtu); + int (*get_mss)(struct dst_entry *dst, u32 mtu); + int entry_size; + + atomic_t entries; + kmem_cache_t *kmem_cachep; +}; + +#ifdef __KERNEL__ + +static inline u32 +dst_metric(const struct dst_entry *dst, int metric) +{ + return dst->metrics[metric-1]; +} + +static inline u32 dst_mtu(const struct dst_entry *dst) +{ + u32 mtu = dst_metric(dst, RTAX_MTU); + /* + * Alexey put it here, so ask him about it :) + */ + barrier(); + return mtu; +} + +static inline u32 +dst_allfrag(const struct dst_entry *dst) +{ + int ret = dst_metric(dst, RTAX_FEATURES) & RTAX_FEATURE_ALLFRAG; + /* Yes, _exactly_. This is paranoia. */ + barrier(); + return ret; +} + +static inline int +dst_metric_locked(struct dst_entry *dst, int metric) +{ + return dst_metric(dst, RTAX_LOCK) & (1<<metric); +} + +static inline void dst_hold(struct dst_entry * dst) +{ + atomic_inc(&dst->__refcnt); +} + +static inline +struct dst_entry * dst_clone(struct dst_entry * dst) +{ + if (dst) + atomic_inc(&dst->__refcnt); + return dst; +} + +static inline +void dst_release(struct dst_entry * dst) +{ + if (dst) { + WARN_ON(atomic_read(&dst->__refcnt) < 1); + smp_mb__before_atomic_dec(); + atomic_dec(&dst->__refcnt); + } +} + +/* Children define the path of the packet through the + * Linux networking. Thus, destinations are stackable. + */ + +static inline struct dst_entry *dst_pop(struct dst_entry *dst) +{ + struct dst_entry *child = dst_clone(dst->child); + + dst_release(dst); + return child; +} + +extern void * dst_alloc(struct dst_ops * ops); +extern void __dst_free(struct dst_entry * dst); +extern struct dst_entry *dst_destroy(struct dst_entry * dst); + +static inline void dst_free(struct dst_entry * dst) +{ + if (dst->obsolete > 1) + return; + if (!atomic_read(&dst->__refcnt)) { + dst = dst_destroy(dst); + if (!dst) + return; + } + __dst_free(dst); +} + +static inline void dst_rcu_free(struct rcu_head *head) +{ + struct dst_entry *dst = container_of(head, struct dst_entry, rcu_head); + dst_free(dst); +} + +static inline void dst_confirm(struct dst_entry *dst) +{ + if (dst) + neigh_confirm(dst->neighbour); +} + +static inline void dst_negative_advice(struct dst_entry **dst_p) +{ + struct dst_entry * dst = *dst_p; + if (dst && dst->ops->negative_advice) + *dst_p = dst->ops->negative_advice(dst); +} + +static inline void dst_link_failure(struct sk_buff *skb) +{ + struct dst_entry * dst = skb->dst; + if (dst && dst->ops && dst->ops->link_failure) + dst->ops->link_failure(skb); +} + +static inline void dst_set_expires(struct dst_entry *dst, int timeout) +{ + unsigned long expires = jiffies + timeout; + + if (expires == 0) + expires = 1; + + if (dst->expires == 0 || time_before(expires, dst->expires)) + dst->expires = expires; +} + +/* Output packet to network from transport. */ +static inline int dst_output(struct sk_buff *skb) +{ + int err; + + for (;;) { + err = skb->dst->output(skb); + + if (likely(err == 0)) + return err; + if (unlikely(err != NET_XMIT_BYPASS)) + return err; + } +} + +/* Input packet from network to transport. */ +static inline int dst_input(struct sk_buff *skb) +{ + int err; + + for (;;) { + err = skb->dst->input(skb); + + if (likely(err == 0)) + return err; + /* Oh, Jamal... Seems, I will not forgive you this mess. :-) */ + if (unlikely(err != NET_XMIT_BYPASS)) + return err; + } +} + +static inline struct dst_entry *dst_check(struct dst_entry *dst, u32 cookie) +{ + if (dst->obsolete) + dst = dst->ops->check(dst, cookie); + return dst; +} + +extern void dst_init(void); + +struct flowi; +#ifndef CONFIG_XFRM +static inline int xfrm_lookup(struct dst_entry **dst_p, struct flowi *fl, + struct sock *sk, int flags) +{ + return 0; +} +#else +extern int xfrm_lookup(struct dst_entry **dst_p, struct flowi *fl, + struct sock *sk, int flags); +#endif +#endif + +#endif /* _NET_DST_H */ |