517 lines
13 KiB
C
517 lines
13 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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/*
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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/bug.h>
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#include <linux/jiffies.h>
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#include <linux/refcount.h>
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#include <net/neighbour.h>
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#include <asm/processor.h>
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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 net_device *dev;
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struct dst_ops *ops;
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unsigned long _metrics;
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unsigned long expires;
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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 net *net, struct sock *sk, struct sk_buff *skb);
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unsigned short flags;
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#define DST_HOST 0x0001
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#define DST_NOXFRM 0x0002
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#define DST_NOPOLICY 0x0004
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#define DST_NOCOUNT 0x0008
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#define DST_FAKE_RTABLE 0x0010
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#define DST_XFRM_TUNNEL 0x0020
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#define DST_XFRM_QUEUE 0x0040
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#define DST_METADATA 0x0080
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/* A non-zero value of dst->obsolete forces by-hand validation
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* of the route entry. Positive values are set by the generic
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* dst layer to indicate that the entry has been forcefully
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* destroyed.
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*
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* Negative values are used by the implementation layer code to
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* force invocation of the dst_ops->check() method.
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*/
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short obsolete;
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#define DST_OBSOLETE_NONE 0
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#define DST_OBSOLETE_DEAD 2
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#define DST_OBSOLETE_FORCE_CHK -1
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#define DST_OBSOLETE_KILL -2
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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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/*
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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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#ifdef CONFIG_64BIT
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atomic_t __refcnt; /* 64-bit offset 64 */
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#endif
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int __use;
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unsigned long lastuse;
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struct lwtunnel_state *lwtstate;
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struct rcu_head rcu_head;
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short error;
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short __pad;
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__u32 tclassid;
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#ifndef CONFIG_64BIT
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atomic_t __refcnt; /* 32-bit offset 64 */
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#endif
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};
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struct dst_metrics {
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u32 metrics[RTAX_MAX];
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refcount_t refcnt;
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};
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extern const struct dst_metrics dst_default_metrics;
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u32 *dst_cow_metrics_generic(struct dst_entry *dst, unsigned long old);
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#define DST_METRICS_READ_ONLY 0x1UL
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#define DST_METRICS_REFCOUNTED 0x2UL
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#define DST_METRICS_FLAGS 0x3UL
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#define __DST_METRICS_PTR(Y) \
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((u32 *)((Y) & ~DST_METRICS_FLAGS))
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#define DST_METRICS_PTR(X) __DST_METRICS_PTR((X)->_metrics)
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static inline bool dst_metrics_read_only(const struct dst_entry *dst)
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{
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return dst->_metrics & DST_METRICS_READ_ONLY;
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}
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void __dst_destroy_metrics_generic(struct dst_entry *dst, unsigned long old);
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static inline void dst_destroy_metrics_generic(struct dst_entry *dst)
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{
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unsigned long val = dst->_metrics;
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if (!(val & DST_METRICS_READ_ONLY))
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__dst_destroy_metrics_generic(dst, val);
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}
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static inline u32 *dst_metrics_write_ptr(struct dst_entry *dst)
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{
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unsigned long p = dst->_metrics;
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BUG_ON(!p);
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if (p & DST_METRICS_READ_ONLY)
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return dst->ops->cow_metrics(dst, p);
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return __DST_METRICS_PTR(p);
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}
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/* This may only be invoked before the entry has reached global
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* visibility.
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*/
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static inline void dst_init_metrics(struct dst_entry *dst,
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const u32 *src_metrics,
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bool read_only)
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{
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dst->_metrics = ((unsigned long) src_metrics) |
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(read_only ? DST_METRICS_READ_ONLY : 0);
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}
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static inline void dst_copy_metrics(struct dst_entry *dest, const struct dst_entry *src)
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{
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u32 *dst_metrics = dst_metrics_write_ptr(dest);
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if (dst_metrics) {
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u32 *src_metrics = DST_METRICS_PTR(src);
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memcpy(dst_metrics, src_metrics, RTAX_MAX * sizeof(u32));
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}
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}
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static inline u32 *dst_metrics_ptr(struct dst_entry *dst)
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{
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return DST_METRICS_PTR(dst);
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}
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static inline u32
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dst_metric_raw(const struct dst_entry *dst, const int metric)
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{
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u32 *p = DST_METRICS_PTR(dst);
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return p[metric-1];
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}
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static inline u32
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dst_metric(const struct dst_entry *dst, const int metric)
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{
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WARN_ON_ONCE(metric == RTAX_HOPLIMIT ||
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metric == RTAX_ADVMSS ||
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metric == RTAX_MTU);
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return dst_metric_raw(dst, metric);
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}
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static inline u32
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dst_metric_advmss(const struct dst_entry *dst)
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{
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u32 advmss = dst_metric_raw(dst, RTAX_ADVMSS);
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if (!advmss)
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advmss = dst->ops->default_advmss(dst);
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return advmss;
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}
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static inline void dst_metric_set(struct dst_entry *dst, int metric, u32 val)
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{
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u32 *p = dst_metrics_write_ptr(dst);
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if (p)
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p[metric-1] = val;
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}
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/* Kernel-internal feature bits that are unallocated in user space. */
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#define DST_FEATURE_ECN_CA (1 << 31)
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#define DST_FEATURE_MASK (DST_FEATURE_ECN_CA)
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#define DST_FEATURE_ECN_MASK (DST_FEATURE_ECN_CA | RTAX_FEATURE_ECN)
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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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return dst->ops->mtu(dst);
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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 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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return ret;
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}
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static inline int
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dst_metric_locked(const 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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* the placement of __refcnt 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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WARN_ON(atomic_inc_not_zero(&dst->__refcnt) == 0);
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}
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static inline void dst_use_noref(struct dst_entry *dst, unsigned long time)
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{
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if (unlikely(time != dst->lastuse)) {
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dst->__use++;
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dst->lastuse = time;
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}
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}
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static inline void dst_hold_and_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_noref(dst, time);
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}
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static inline struct dst_entry *dst_clone(struct dst_entry *dst)
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{
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if (dst)
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dst_hold(dst);
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return dst;
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}
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void dst_release(struct dst_entry *dst);
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void dst_release_immediate(struct dst_entry *dst);
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static inline void refdst_drop(unsigned long refdst)
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{
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if (!(refdst & SKB_DST_NOREF))
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dst_release((struct dst_entry *)(refdst & SKB_DST_PTRMASK));
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}
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/**
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* skb_dst_drop - drops skb dst
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* @skb: buffer
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*
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* Drops dst reference count if a reference was taken.
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*/
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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_refdst) {
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refdst_drop(skb->_skb_refdst);
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skb->_skb_refdst = 0UL;
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}
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}
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static inline void __skb_dst_copy(struct sk_buff *nskb, unsigned long refdst)
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{
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nskb->_skb_refdst = refdst;
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if (!(nskb->_skb_refdst & SKB_DST_NOREF))
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dst_clone(skb_dst(nskb));
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}
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static inline void skb_dst_copy(struct sk_buff *nskb, const struct sk_buff *oskb)
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{
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__skb_dst_copy(nskb, oskb->_skb_refdst);
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}
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/**
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* dst_hold_safe - Take a reference on a dst if possible
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* @dst: pointer to dst entry
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*
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* This helper returns false if it could not safely
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* take a reference on a dst.
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*/
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static inline bool dst_hold_safe(struct dst_entry *dst)
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{
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return atomic_inc_not_zero(&dst->__refcnt);
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}
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/**
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* skb_dst_force - makes sure skb dst is refcounted
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* @skb: buffer
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*
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* If dst is not yet refcounted and not destroyed, grab a ref on it.
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*/
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static inline void skb_dst_force(struct sk_buff *skb)
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{
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if (skb_dst_is_noref(skb)) {
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struct dst_entry *dst = skb_dst(skb);
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WARN_ON(!rcu_read_lock_held());
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if (!dst_hold_safe(dst))
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dst = NULL;
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skb->_skb_refdst = (unsigned long)dst;
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}
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}
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/**
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* __skb_tunnel_rx - prepare skb for rx reinsert
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* @skb: buffer
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* @dev: tunnel device
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* @net: netns for packet i/o
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*
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* After decapsulation, packet is going to re-enter (netif_rx()) our stack,
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* so make some cleanups. (no accounting done)
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*/
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static inline void __skb_tunnel_rx(struct sk_buff *skb, struct net_device *dev,
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struct net *net)
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{
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skb->dev = dev;
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/*
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* Clear hash so that we can recalulate the hash for the
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* encapsulated packet, unless we have already determine the hash
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* over the L4 4-tuple.
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*/
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skb_clear_hash_if_not_l4(skb);
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skb_set_queue_mapping(skb, 0);
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skb_scrub_packet(skb, !net_eq(net, dev_net(dev)));
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}
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/**
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* skb_tunnel_rx - prepare skb for rx reinsert
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* @skb: buffer
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* @dev: tunnel device
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* @net: netns for packet i/o
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*
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* After decapsulation, packet is going to re-enter (netif_rx()) our stack,
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* so make some cleanups, and perform accounting.
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* Note: this accounting is not SMP safe.
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*/
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static inline void skb_tunnel_rx(struct sk_buff *skb, struct net_device *dev,
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struct net *net)
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{
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/* TODO : stats should be SMP safe */
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dev->stats.rx_packets++;
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dev->stats.rx_bytes += skb->len;
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__skb_tunnel_rx(skb, dev, net);
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}
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static inline u32 dst_tclassid(const struct sk_buff *skb)
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{
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#ifdef CONFIG_IP_ROUTE_CLASSID
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const struct dst_entry *dst;
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dst = skb_dst(skb);
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if (dst)
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return dst->tclassid;
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#endif
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return 0;
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}
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int dst_discard_out(struct net *net, struct sock *sk, struct sk_buff *skb);
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static inline int dst_discard(struct sk_buff *skb)
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{
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return dst_discard_out(&init_net, skb->sk, skb);
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}
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void *dst_alloc(struct dst_ops *ops, struct net_device *dev, int initial_ref,
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int initial_obsolete, unsigned short flags);
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void dst_init(struct dst_entry *dst, struct dst_ops *ops,
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struct net_device *dev, int initial_ref, int initial_obsolete,
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unsigned short flags);
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struct dst_entry *dst_destroy(struct dst_entry *dst);
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void dst_dev_put(struct dst_entry *dst);
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static inline void dst_confirm(struct dst_entry *dst)
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{
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}
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static inline struct neighbour *dst_neigh_lookup(const struct dst_entry *dst, const void *daddr)
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{
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struct neighbour *n = dst->ops->neigh_lookup(dst, NULL, daddr);
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return IS_ERR(n) ? NULL : n;
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}
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static inline struct neighbour *dst_neigh_lookup_skb(const struct dst_entry *dst,
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struct sk_buff *skb)
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{
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struct neighbour *n = dst->ops->neigh_lookup(dst, skb, NULL);
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return IS_ERR(n) ? NULL : n;
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}
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static inline void dst_confirm_neigh(const struct dst_entry *dst,
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const void *daddr)
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{
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if (dst->ops->confirm_neigh)
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dst->ops->confirm_neigh(dst, daddr);
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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 net *net, struct sock *sk, struct sk_buff *skb)
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{
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return skb_dst(skb)->output(net, sk, 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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/* Flags for xfrm_lookup flags argument. */
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enum {
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XFRM_LOOKUP_ICMP = 1 << 0,
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XFRM_LOOKUP_QUEUE = 1 << 1,
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XFRM_LOOKUP_KEEP_DST_REF = 1 << 2,
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};
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struct flowi;
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#ifndef CONFIG_XFRM
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static inline struct dst_entry *xfrm_lookup(struct net *net,
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struct dst_entry *dst_orig,
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const struct flowi *fl,
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const struct sock *sk,
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int flags)
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{
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return dst_orig;
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}
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static inline struct dst_entry *xfrm_lookup_route(struct net *net,
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struct dst_entry *dst_orig,
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const struct flowi *fl,
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const struct sock *sk,
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int flags)
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{
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return dst_orig;
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}
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static inline struct xfrm_state *dst_xfrm(const struct dst_entry *dst)
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{
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return NULL;
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}
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#else
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struct dst_entry *xfrm_lookup(struct net *net, struct dst_entry *dst_orig,
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const struct flowi *fl, const struct sock *sk,
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int flags);
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struct dst_entry *xfrm_lookup_route(struct net *net, struct dst_entry *dst_orig,
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const struct flowi *fl, const struct sock *sk,
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int flags);
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/* skb attached with this dst needs transformation if dst->xfrm is valid */
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static inline struct xfrm_state *dst_xfrm(const struct dst_entry *dst)
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{
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return dst->xfrm;
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}
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#endif
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static inline void skb_dst_update_pmtu(struct sk_buff *skb, u32 mtu)
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{
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struct dst_entry *dst = skb_dst(skb);
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if (dst && dst->ops->update_pmtu)
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dst->ops->update_pmtu(dst, NULL, skb, mtu);
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}
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#endif /* _NET_DST_H */
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