| /* |
| * 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/netdevice.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 rcu_head rcu_head; |
| 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 |
| 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; |
| |
| unsigned long lastuse; |
| atomic_t __refcnt; /* client references */ |
| int __use; |
| union { |
| struct dst_entry *next; |
| struct rtable *rt_next; |
| struct rt6_info *rt6_next; |
| struct dn_route *dn_next; |
| }; |
| }; |
| |
| |
| struct dst_ops |
| { |
| unsigned short family; |
| __be16 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 (*local_out)(struct sk_buff *skb); |
| int entry_size; |
| |
| atomic_t entries; |
| struct kmem_cache *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 void dst_use(struct dst_entry *dst, unsigned long time) |
| { |
| dst_hold(dst); |
| dst->__use++; |
| dst->lastuse = time; |
| } |
| |
| 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 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_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) |
| { |
| return skb->dst->output(skb); |
| } |
| |
| /* 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); |
| |
| /* 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 dst_entry **dst_p, struct flowi *fl, |
| struct sock *sk, int flags) |
| { |
| return 0; |
| } |
| 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); |
| extern int __xfrm_lookup(struct dst_entry **dst_p, struct flowi *fl, |
| struct sock *sk, int flags); |
| #endif |
| #endif |
| |
| #endif /* _NET_DST_H */ |