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 */