/* * 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; short error; short 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; 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 */