309 lines
6.7 KiB
C
309 lines
6.7 KiB
C
/*
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* net/dst.h Protocol independent destination cache definitions.
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*
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* Authors: Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
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*
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*/
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#ifndef _NET_DST_H
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#define _NET_DST_H
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#include <net/dst_ops.h>
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#include <linux/netdevice.h>
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#include <linux/rtnetlink.h>
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#include <linux/rcupdate.h>
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#include <linux/jiffies.h>
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#include <net/neighbour.h>
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#include <asm/processor.h>
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/*
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* 0 - no debugging messages
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* 1 - rare events and bugs (default)
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* 2 - trace mode.
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*/
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#define RT_CACHE_DEBUG 0
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#define DST_GC_MIN (HZ/10)
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#define DST_GC_INC (HZ/2)
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#define DST_GC_MAX (120*HZ)
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/* Each dst_entry has reference count and sits in some parent list(s).
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* When it is removed from parent list, it is "freed" (dst_free).
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* After this it enters dead state (dst->obsolete > 0) and if its refcnt
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* is zero, it can be destroyed immediately, otherwise it is added
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* to gc list and garbage collector periodically checks the refcnt.
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*/
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struct sk_buff;
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struct dst_entry {
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struct rcu_head rcu_head;
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struct dst_entry *child;
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struct net_device *dev;
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short error;
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short obsolete;
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int flags;
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#define DST_HOST 1
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#define DST_NOXFRM 2
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#define DST_NOPOLICY 4
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#define DST_NOHASH 8
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unsigned long expires;
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unsigned short header_len; /* more space at head required */
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unsigned short trailer_len; /* space to reserve at tail */
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unsigned int rate_tokens;
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unsigned long rate_last; /* rate limiting for ICMP */
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struct dst_entry *path;
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struct neighbour *neighbour;
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struct hh_cache *hh;
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#ifdef CONFIG_XFRM
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struct xfrm_state *xfrm;
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#else
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void *__pad1;
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#endif
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int (*input)(struct sk_buff*);
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int (*output)(struct sk_buff*);
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struct dst_ops *ops;
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u32 metrics[RTAX_MAX];
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#ifdef CONFIG_NET_CLS_ROUTE
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__u32 tclassid;
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#else
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__u32 __pad2;
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#endif
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/*
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* Align __refcnt to a 64 bytes alignment
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* (L1_CACHE_SIZE would be too much)
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*/
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#ifdef CONFIG_64BIT
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long __pad_to_align_refcnt[1];
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#endif
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/*
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* __refcnt wants to be on a different cache line from
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* input/output/ops or performance tanks badly
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*/
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atomic_t __refcnt; /* client references */
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int __use;
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unsigned long lastuse;
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union {
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struct dst_entry *next;
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struct rtable *rt_next;
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struct rt6_info *rt6_next;
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struct dn_route *dn_next;
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};
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};
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#ifdef __KERNEL__
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static inline u32
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dst_metric(const struct dst_entry *dst, int metric)
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{
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return dst->metrics[metric-1];
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}
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static inline u32
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dst_feature(const struct dst_entry *dst, u32 feature)
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{
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return dst_metric(dst, RTAX_FEATURES) & feature;
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}
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static inline u32 dst_mtu(const struct dst_entry *dst)
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{
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u32 mtu = dst_metric(dst, RTAX_MTU);
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/*
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* Alexey put it here, so ask him about it :)
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*/
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barrier();
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return mtu;
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}
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/* RTT metrics are stored in milliseconds for user ABI, but used as jiffies */
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static inline unsigned long dst_metric_rtt(const struct dst_entry *dst, int metric)
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{
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return msecs_to_jiffies(dst_metric(dst, metric));
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}
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static inline void set_dst_metric_rtt(struct dst_entry *dst, int metric,
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unsigned long rtt)
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{
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dst->metrics[metric-1] = jiffies_to_msecs(rtt);
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}
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static inline u32
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dst_allfrag(const struct dst_entry *dst)
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{
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int ret = dst_feature(dst, RTAX_FEATURE_ALLFRAG);
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/* Yes, _exactly_. This is paranoia. */
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barrier();
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return ret;
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}
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static inline int
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dst_metric_locked(struct dst_entry *dst, int metric)
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{
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return dst_metric(dst, RTAX_LOCK) & (1<<metric);
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}
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static inline void dst_hold(struct dst_entry * dst)
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{
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/*
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* If your kernel compilation stops here, please check
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* __pad_to_align_refcnt declaration in struct dst_entry
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*/
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BUILD_BUG_ON(offsetof(struct dst_entry, __refcnt) & 63);
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atomic_inc(&dst->__refcnt);
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}
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static inline void dst_use(struct dst_entry *dst, unsigned long time)
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{
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dst_hold(dst);
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dst->__use++;
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dst->lastuse = time;
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}
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static inline
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struct dst_entry * dst_clone(struct dst_entry * dst)
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{
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if (dst)
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atomic_inc(&dst->__refcnt);
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return dst;
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}
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extern void dst_release(struct dst_entry *dst);
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static inline void skb_dst_drop(struct sk_buff *skb)
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{
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if (skb->_skb_dst)
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dst_release(skb_dst(skb));
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skb->_skb_dst = 0UL;
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}
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/* Children define the path of the packet through the
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* Linux networking. Thus, destinations are stackable.
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*/
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static inline struct dst_entry *dst_pop(struct dst_entry *dst)
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{
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struct dst_entry *child = dst_clone(dst->child);
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dst_release(dst);
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return child;
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}
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extern int dst_discard(struct sk_buff *skb);
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extern void * dst_alloc(struct dst_ops * ops);
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extern void __dst_free(struct dst_entry * dst);
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extern struct dst_entry *dst_destroy(struct dst_entry * dst);
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static inline void dst_free(struct dst_entry * dst)
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{
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if (dst->obsolete > 1)
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return;
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if (!atomic_read(&dst->__refcnt)) {
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dst = dst_destroy(dst);
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if (!dst)
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return;
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}
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__dst_free(dst);
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}
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static inline void dst_rcu_free(struct rcu_head *head)
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{
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struct dst_entry *dst = container_of(head, struct dst_entry, rcu_head);
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dst_free(dst);
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}
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static inline void dst_confirm(struct dst_entry *dst)
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{
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if (dst)
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neigh_confirm(dst->neighbour);
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}
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static inline void dst_negative_advice(struct dst_entry **dst_p,
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struct sock *sk)
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{
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struct dst_entry * dst = *dst_p;
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if (dst && dst->ops->negative_advice) {
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*dst_p = dst->ops->negative_advice(dst);
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if (dst != *dst_p) {
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extern void sk_reset_txq(struct sock *sk);
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sk_reset_txq(sk);
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}
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}
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}
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static inline void dst_link_failure(struct sk_buff *skb)
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{
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struct dst_entry *dst = skb_dst(skb);
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if (dst && dst->ops && dst->ops->link_failure)
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dst->ops->link_failure(skb);
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}
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static inline void dst_set_expires(struct dst_entry *dst, int timeout)
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{
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unsigned long expires = jiffies + timeout;
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if (expires == 0)
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expires = 1;
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if (dst->expires == 0 || time_before(expires, dst->expires))
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dst->expires = expires;
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}
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/* Output packet to network from transport. */
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static inline int dst_output(struct sk_buff *skb)
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{
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return skb_dst(skb)->output(skb);
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}
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/* Input packet from network to transport. */
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static inline int dst_input(struct sk_buff *skb)
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{
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return skb_dst(skb)->input(skb);
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}
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static inline struct dst_entry *dst_check(struct dst_entry *dst, u32 cookie)
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{
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if (dst->obsolete)
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dst = dst->ops->check(dst, cookie);
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return dst;
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}
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extern void dst_init(void);
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/* Flags for xfrm_lookup flags argument. */
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enum {
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XFRM_LOOKUP_WAIT = 1 << 0,
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XFRM_LOOKUP_ICMP = 1 << 1,
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};
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struct flowi;
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#ifndef CONFIG_XFRM
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static inline int xfrm_lookup(struct net *net, struct dst_entry **dst_p,
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struct flowi *fl, struct sock *sk, int flags)
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{
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return 0;
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}
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static inline int __xfrm_lookup(struct net *net, struct dst_entry **dst_p,
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struct flowi *fl, struct sock *sk, int flags)
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{
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return 0;
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}
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#else
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extern int xfrm_lookup(struct net *net, struct dst_entry **dst_p,
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struct flowi *fl, struct sock *sk, int flags);
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extern int __xfrm_lookup(struct net *net, struct dst_entry **dst_p,
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struct flowi *fl, struct sock *sk, int flags);
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#endif
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#endif
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#endif /* _NET_DST_H */
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