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-rw-r--r--include/net/dst.h279
1 files changed, 279 insertions, 0 deletions
diff --git a/include/net/dst.h b/include/net/dst.h
new file mode 100644
index 0000000..50adc91
--- /dev/null
+++ b/include/net/dst.h
@@ -0,0 +1,279 @@
+/*
+ * net/dst.h Protocol independent destination cache definitions.
+ *
+ * Authors: Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
+ *
+ */
+
+#ifndef _NET_DST_H
+#define _NET_DST_H
+
+#include <linux/config.h>
+#include <linux/rtnetlink.h>
+#include <linux/rcupdate.h>
+#include <linux/jiffies.h>
+#include <net/neighbour.h>
+#include <asm/processor.h>
+
+/*
+ * 0 - no debugging messages
+ * 1 - rare events and bugs (default)
+ * 2 - trace mode.
+ */
+#define RT_CACHE_DEBUG 0
+
+#define DST_GC_MIN (HZ/10)
+#define DST_GC_INC (HZ/2)
+#define DST_GC_MAX (120*HZ)
+
+/* Each dst_entry has reference count and sits in some parent list(s).
+ * When it is removed from parent list, it is "freed" (dst_free).
+ * After this it enters dead state (dst->obsolete > 0) and if its refcnt
+ * is zero, it can be destroyed immediately, otherwise it is added
+ * to gc list and garbage collector periodically checks the refcnt.
+ */
+
+struct sk_buff;
+
+struct dst_entry
+{
+ struct dst_entry *next;
+ atomic_t __refcnt; /* client references */
+ int __use;
+ struct dst_entry *child;
+ struct net_device *dev;
+ int obsolete;
+ int flags;
+#define DST_HOST 1
+#define DST_NOXFRM 2
+#define DST_NOPOLICY 4
+#define DST_NOHASH 8
+#define DST_BALANCED 0x10
+ unsigned long lastuse;
+ unsigned long expires;
+
+ unsigned short header_len; /* more space at head required */
+ unsigned short trailer_len; /* space to reserve at tail */
+
+ u32 metrics[RTAX_MAX];
+ struct dst_entry *path;
+
+ unsigned long rate_last; /* rate limiting for ICMP */
+ unsigned long rate_tokens;
+
+ int error;
+
+ struct neighbour *neighbour;
+ struct hh_cache *hh;
+ struct xfrm_state *xfrm;
+
+ int (*input)(struct sk_buff*);
+ int (*output)(struct sk_buff*);
+
+#ifdef CONFIG_NET_CLS_ROUTE
+ __u32 tclassid;
+#endif
+
+ struct dst_ops *ops;
+ struct rcu_head rcu_head;
+
+ char info[0];
+};
+
+
+struct dst_ops
+{
+ unsigned short family;
+ unsigned short protocol;
+ unsigned gc_thresh;
+
+ int (*gc)(void);
+ struct dst_entry * (*check)(struct dst_entry *, __u32 cookie);
+ void (*destroy)(struct dst_entry *);
+ void (*ifdown)(struct dst_entry *,
+ struct net_device *dev, int how);
+ struct dst_entry * (*negative_advice)(struct dst_entry *);
+ void (*link_failure)(struct sk_buff *);
+ void (*update_pmtu)(struct dst_entry *dst, u32 mtu);
+ int (*get_mss)(struct dst_entry *dst, u32 mtu);
+ int entry_size;
+
+ atomic_t entries;
+ kmem_cache_t *kmem_cachep;
+};
+
+#ifdef __KERNEL__
+
+static inline u32
+dst_metric(const struct dst_entry *dst, int metric)
+{
+ return dst->metrics[metric-1];
+}
+
+static inline u32 dst_mtu(const struct dst_entry *dst)
+{
+ u32 mtu = dst_metric(dst, RTAX_MTU);
+ /*
+ * Alexey put it here, so ask him about it :)
+ */
+ barrier();
+ return mtu;
+}
+
+static inline u32
+dst_allfrag(const struct dst_entry *dst)
+{
+ int ret = dst_metric(dst, RTAX_FEATURES) & RTAX_FEATURE_ALLFRAG;
+ /* Yes, _exactly_. This is paranoia. */
+ barrier();
+ return ret;
+}
+
+static inline int
+dst_metric_locked(struct dst_entry *dst, int metric)
+{
+ return dst_metric(dst, RTAX_LOCK) & (1<<metric);
+}
+
+static inline void dst_hold(struct dst_entry * dst)
+{
+ atomic_inc(&dst->__refcnt);
+}
+
+static inline
+struct dst_entry * dst_clone(struct dst_entry * dst)
+{
+ if (dst)
+ atomic_inc(&dst->__refcnt);
+ return dst;
+}
+
+static inline
+void dst_release(struct dst_entry * dst)
+{
+ if (dst) {
+ WARN_ON(atomic_read(&dst->__refcnt) < 1);
+ smp_mb__before_atomic_dec();
+ atomic_dec(&dst->__refcnt);
+ }
+}
+
+/* Children define the path of the packet through the
+ * Linux networking. Thus, destinations are stackable.
+ */
+
+static inline struct dst_entry *dst_pop(struct dst_entry *dst)
+{
+ struct dst_entry *child = dst_clone(dst->child);
+
+ dst_release(dst);
+ return child;
+}
+
+extern void * dst_alloc(struct dst_ops * ops);
+extern void __dst_free(struct dst_entry * dst);
+extern struct dst_entry *dst_destroy(struct dst_entry * dst);
+
+static inline void dst_free(struct dst_entry * dst)
+{
+ if (dst->obsolete > 1)
+ return;
+ if (!atomic_read(&dst->__refcnt)) {
+ dst = dst_destroy(dst);
+ if (!dst)
+ return;
+ }
+ __dst_free(dst);
+}
+
+static inline void dst_rcu_free(struct rcu_head *head)
+{
+ struct dst_entry *dst = container_of(head, struct dst_entry, rcu_head);
+ dst_free(dst);
+}
+
+static inline void dst_confirm(struct dst_entry *dst)
+{
+ if (dst)
+ neigh_confirm(dst->neighbour);
+}
+
+static inline void dst_negative_advice(struct dst_entry **dst_p)
+{
+ struct dst_entry * dst = *dst_p;
+ if (dst && dst->ops->negative_advice)
+ *dst_p = dst->ops->negative_advice(dst);
+}
+
+static inline void dst_link_failure(struct sk_buff *skb)
+{
+ struct dst_entry * dst = skb->dst;
+ if (dst && dst->ops && dst->ops->link_failure)
+ dst->ops->link_failure(skb);
+}
+
+static inline void dst_set_expires(struct dst_entry *dst, int timeout)
+{
+ unsigned long expires = jiffies + timeout;
+
+ if (expires == 0)
+ expires = 1;
+
+ if (dst->expires == 0 || time_before(expires, dst->expires))
+ dst->expires = expires;
+}
+
+/* Output packet to network from transport. */
+static inline int dst_output(struct sk_buff *skb)
+{
+ int err;
+
+ for (;;) {
+ err = skb->dst->output(skb);
+
+ if (likely(err == 0))
+ return err;
+ if (unlikely(err != NET_XMIT_BYPASS))
+ return err;
+ }
+}
+
+/* Input packet from network to transport. */
+static inline int dst_input(struct sk_buff *skb)
+{
+ int err;
+
+ for (;;) {
+ err = skb->dst->input(skb);
+
+ if (likely(err == 0))
+ return err;
+ /* Oh, Jamal... Seems, I will not forgive you this mess. :-) */
+ if (unlikely(err != NET_XMIT_BYPASS))
+ return err;
+ }
+}
+
+static inline struct dst_entry *dst_check(struct dst_entry *dst, u32 cookie)
+{
+ if (dst->obsolete)
+ dst = dst->ops->check(dst, cookie);
+ return dst;
+}
+
+extern void dst_init(void);
+
+struct flowi;
+#ifndef CONFIG_XFRM
+static inline int xfrm_lookup(struct dst_entry **dst_p, struct flowi *fl,
+ struct sock *sk, int flags)
+{
+ return 0;
+}
+#else
+extern int xfrm_lookup(struct dst_entry **dst_p, struct flowi *fl,
+ struct sock *sk, int flags);
+#endif
+#endif
+
+#endif /* _NET_DST_H */
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