/* * net/dst.h Protocol independent destination cache definitions. * * Authors: Alexey Kuznetsov, * */ #ifndef _NET_DST_H #define _NET_DST_H #include #include #include #include #include #include #include /* * 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 rcu_head rcu_head; struct dst_entry *child; struct net_device *dev; short error; short obsolete; int flags; #define DST_HOST 0x0001 #define DST_NOXFRM 0x0002 #define DST_NOPOLICY 0x0004 #define DST_NOHASH 0x0008 #define DST_NOCACHE 0x0010 unsigned long expires; unsigned short header_len; /* more space at head required */ unsigned short trailer_len; /* space to reserve at tail */ unsigned int rate_tokens; unsigned long rate_last; /* rate limiting for ICMP */ struct dst_entry *path; struct neighbour *neighbour; struct hh_cache *hh; #ifdef CONFIG_XFRM struct xfrm_state *xfrm; #else void *__pad1; #endif int (*input)(struct sk_buff*); int (*output)(struct sk_buff*); struct dst_ops *ops; u32 _metrics[RTAX_MAX]; #ifdef CONFIG_NET_CLS_ROUTE __u32 tclassid; #else __u32 __pad2; #endif /* * Align __refcnt to a 64 bytes alignment * (L1_CACHE_SIZE would be too much) */ #ifdef CONFIG_64BIT long __pad_to_align_refcnt[1]; #endif /* * __refcnt wants to be on a different cache line from * input/output/ops or performance tanks badly */ atomic_t __refcnt; /* client references */ int __use; unsigned long lastuse; union { struct dst_entry *next; struct rtable __rcu *rt_next; struct rt6_info *rt6_next; struct dn_route __rcu *dn_next; }; }; #ifdef __KERNEL__ static inline u32 dst_metric(const struct dst_entry *dst, int metric) { return dst->_metrics[metric-1]; } static inline void dst_metric_set(struct dst_entry *dst, int metric, u32 val) { dst->_metrics[metric-1] = val; } static inline void dst_import_metrics(struct dst_entry *dst, const u32 *src_metrics) { memcpy(dst->_metrics, src_metrics, RTAX_MAX * sizeof(u32)); } static inline void dst_copy_metrics(struct dst_entry *dest, const struct dst_entry *src) { dst_import_metrics(dest, src->_metrics); } static inline u32 *dst_metrics_ptr(struct dst_entry *dst) { return dst->_metrics; } static inline u32 dst_feature(const struct dst_entry *dst, u32 feature) { return dst_metric(dst, RTAX_FEATURES) & feature; } 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; } /* RTT metrics are stored in milliseconds for user ABI, but used as jiffies */ static inline unsigned long dst_metric_rtt(const struct dst_entry *dst, int metric) { return msecs_to_jiffies(dst_metric(dst, metric)); } static inline void set_dst_metric_rtt(struct dst_entry *dst, int metric, unsigned long rtt) { dst_metric_set(dst, metric, jiffies_to_msecs(rtt)); } static inline u32 dst_allfrag(const struct dst_entry *dst) { int ret = dst_feature(dst, 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<__refcnt); } static inline void dst_use(struct dst_entry *dst, unsigned long time) { dst_hold(dst); dst->__use++; dst->lastuse = time; } static inline void dst_use_noref(struct dst_entry *dst, unsigned long time) { dst->__use++; dst->lastuse = time; } static inline struct dst_entry * dst_clone(struct dst_entry * dst) { if (dst) atomic_inc(&dst->__refcnt); return dst; } extern void dst_release(struct dst_entry *dst); static inline void refdst_drop(unsigned long refdst) { if (!(refdst & SKB_DST_NOREF)) dst_release((struct dst_entry *)(refdst & SKB_DST_PTRMASK)); } /** * skb_dst_drop - drops skb dst * @skb: buffer * * Drops dst reference count if a reference was taken. */ static inline void skb_dst_drop(struct sk_buff *skb) { if (skb->_skb_refdst) { refdst_drop(skb->_skb_refdst); skb->_skb_refdst = 0UL; } } static inline void skb_dst_copy(struct sk_buff *nskb, const struct sk_buff *oskb) { nskb->_skb_refdst = oskb->_skb_refdst; if (!(nskb->_skb_refdst & SKB_DST_NOREF)) dst_clone(skb_dst(nskb)); } /** * skb_dst_force - makes sure skb dst is refcounted * @skb: buffer * * If dst is not yet refcounted, let's do it */ static inline void skb_dst_force(struct sk_buff *skb) { if (skb_dst_is_noref(skb)) { WARN_ON(!rcu_read_lock_held()); skb->_skb_refdst &= ~SKB_DST_NOREF; dst_clone(skb_dst(skb)); } } /** * __skb_tunnel_rx - prepare skb for rx reinsert * @skb: buffer * @dev: tunnel device * * After decapsulation, packet is going to re-enter (netif_rx()) our stack, * so make some cleanups. (no accounting done) */ static inline void __skb_tunnel_rx(struct sk_buff *skb, struct net_device *dev) { skb->dev = dev; skb->rxhash = 0; skb_set_queue_mapping(skb, 0); skb_dst_drop(skb); nf_reset(skb); } /** * skb_tunnel_rx - prepare skb for rx reinsert * @skb: buffer * @dev: tunnel device * * After decapsulation, packet is going to re-enter (netif_rx()) our stack, * so make some cleanups, and perform accounting. * Note: this accounting is not SMP safe. */ static inline void skb_tunnel_rx(struct sk_buff *skb, struct net_device *dev) { /* TODO : stats should be SMP safe */ dev->stats.rx_packets++; dev->stats.rx_bytes += skb->len; __skb_tunnel_rx(skb, dev); } /* Children define the path of the packet through the * Linux networking. Thus, destinations are stackable. */ static inline struct dst_entry *skb_dst_pop(struct sk_buff *skb) { struct dst_entry *child = skb_dst(skb)->child; skb_dst_drop(skb); return child; } extern int dst_discard(struct sk_buff *skb); 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_link_failure(struct sk_buff *skb) { struct dst_entry *dst = skb_dst(skb); 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) { return skb_dst(skb)->output(skb); } /* Input packet from network to transport. */ static inline int dst_input(struct sk_buff *skb) { return skb_dst(skb)->input(skb); } 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); /* Flags for xfrm_lookup flags argument. */ enum { XFRM_LOOKUP_WAIT = 1 << 0, XFRM_LOOKUP_ICMP = 1 << 1, }; struct flowi; #ifndef CONFIG_XFRM static inline int xfrm_lookup(struct net *net, struct dst_entry **dst_p, struct flowi *fl, struct sock *sk, int flags) { return 0; } static inline int __xfrm_lookup(struct net *net, struct dst_entry **dst_p, struct flowi *fl, struct sock *sk, int flags) { return 0; } #else extern int xfrm_lookup(struct net *net, struct dst_entry **dst_p, struct flowi *fl, struct sock *sk, int flags); extern int __xfrm_lookup(struct net *net, struct dst_entry **dst_p, struct flowi *fl, struct sock *sk, int flags); #endif #endif #endif /* _NET_DST_H */