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567 lines
14 KiB
567 lines
14 KiB
/* |
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* net/dst.h Protocol independent destination cache definitions. |
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* |
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* Authors: Alexey Kuznetsov, <[email protected]> |
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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 <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 rcu_head rcu_head; |
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struct dst_entry *child; |
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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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struct dst_entry *path; |
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struct dst_entry *from; |
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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_NOHASH 0x0008 |
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#define DST_NOCACHE 0x0010 |
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#define DST_NOCOUNT 0x0020 |
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#define DST_FAKE_RTABLE 0x0040 |
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#define DST_XFRM_TUNNEL 0x0080 |
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#define DST_XFRM_QUEUE 0x0100 |
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#define DST_METADATA 0x0200 |
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unsigned short pending_confirm; |
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short error; |
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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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#ifdef CONFIG_IP_ROUTE_CLASSID |
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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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#ifdef CONFIG_64BIT |
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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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long __pad_to_align_refcnt[2]; |
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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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struct lwtunnel_state *lwtstate; |
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union { |
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struct dst_entry *next; |
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struct rtable __rcu *rt_next; |
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struct rt6_info *rt6_next; |
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struct dn_route __rcu *dn_next; |
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}; |
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}; |
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u32 *dst_cow_metrics_generic(struct dst_entry *dst, unsigned long old); |
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extern const u32 dst_default_metrics[]; |
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#define DST_METRICS_READ_ONLY 0x1UL |
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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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* __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 void dst_use_noref(struct dst_entry *dst, unsigned long time) |
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{ |
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dst->__use++; |
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dst->lastuse = 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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atomic_inc(&dst->__refcnt); |
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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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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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* 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, let's do 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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WARN_ON(!rcu_read_lock_held()); |
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skb->_skb_refdst &= ~SKB_DST_NOREF; |
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dst_clone(skb_dst(skb)); |
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} |
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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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if (dst->flags & DST_NOCACHE) |
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return atomic_inc_not_zero(&dst->__refcnt); |
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dst_hold(dst); |
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return true; |
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} |
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/** |
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* skb_dst_force_safe - 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_safe(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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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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* |
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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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void __dst_free(struct dst_entry *dst); |
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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 > 0) |
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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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dst->pending_confirm = 1; |
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} |
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static inline int dst_neigh_output(struct dst_entry *dst, struct neighbour *n, |
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struct sk_buff *skb) |
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{ |
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const struct hh_cache *hh; |
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if (dst->pending_confirm) { |
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unsigned long now = jiffies; |
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dst->pending_confirm = 0; |
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/* avoid dirtying neighbour */ |
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if (n->confirmed != now) |
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n->confirmed = now; |
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} |
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hh = &n->hh; |
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if ((n->nud_state & NUD_CONNECTED) && hh->hh_len) |
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return neigh_hh_output(hh, skb); |
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else |
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return n->output(n, skb); |
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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_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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void dst_subsys_init(void); |
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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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#endif /* _NET_DST_H */
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