1 files changed, 459 insertions, 0 deletions
diff --git a/include/net/dst.h b/include/net/dst.h
new file mode 100644
index 00000000..7907ff15
--- /dev/null
+++ b/include/net/dst.h
@@ -0,0 +1,459 @@
+/*
+ * 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 <net/dst_ops.h>
+#include <linux/netdevice.h>
+#include <linux/rtnetlink.h>
+#include <linux/rcupdate.h>
+#include <linux/jiffies.h>
+#include <net/neighbour.h>
+#include <asm/processor.h>
+
+#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 rcu_head		rcu_head;
+	struct dst_entry	*child;
+	struct net_device       *dev;
+	struct  dst_ops	        *ops;
+	unsigned long		_metrics;
+	unsigned long		expires;
+	struct dst_entry	*path;
+	struct neighbour __rcu	*_neighbour;
+	struct hh_cache		*hh;
+#ifdef CONFIG_XFRM
+	struct xfrm_state	*xfrm;
+#else
+	void			*__pad1;
+#endif
+	int			(*input)(struct sk_buff*);
+	int			(*output)(struct sk_buff*);
+
+	short			error;
+	short			obsolete;
+	unsigned short		header_len;	/* more space at head required */
+	unsigned short		trailer_len;	/* space to reserve at tail */
+#ifdef CONFIG_IP_ROUTE_CLASSID
+	__u32			tclassid;
+#else
+	__u32			__pad2;
+#endif
+
+	/*
+	 * Align __refcnt to a 64 bytes alignment
+	 * (L1_CACHE_SIZE would be too much)
+	 */
+#ifdef CONFIG_64BIT
+	long			__pad_to_align_refcnt[1];
+#endif
+	/*
+	 * __refcnt wants to be on a different cache line from
+	 * input/output/ops or performance tanks badly
+	 */
+	atomic_t		__refcnt;	/* client references	*/
+	int			__use;
+	unsigned long		lastuse;
+	int			flags;
+#define DST_HOST		0x0001
+#define DST_NOXFRM		0x0002
+#define DST_NOPOLICY		0x0004
+#define DST_NOHASH		0x0008
+#define DST_NOCACHE		0x0010
+#define DST_NOCOUNT		0x0020
+#define DST_XFRM_TUNNEL		0x0100
+	union {
+		struct dst_entry	*next;
+		struct rtable __rcu	*rt_next;
+		struct rt6_info		*rt6_next;
+		struct dn_route __rcu	*dn_next;
+	};
+};
+
+static inline struct neighbour *dst_get_neighbour(struct dst_entry *dst)
+{
+	return rcu_dereference(dst->_neighbour);
+}
+
+static inline struct neighbour *dst_get_neighbour_raw(struct dst_entry *dst)
+{
+	return rcu_dereference_raw(dst->_neighbour);
+}
+
+static inline void dst_set_neighbour(struct dst_entry *dst, struct neighbour *neigh)
+{
+	rcu_assign_pointer(dst->_neighbour, neigh);
+}
+
+extern u32 *dst_cow_metrics_generic(struct dst_entry *dst, unsigned long old);
+extern const u32 dst_default_metrics[RTAX_MAX];
+
+#define DST_METRICS_READ_ONLY	0x1UL
+#define __DST_METRICS_PTR(Y)	\
+	((u32 *)((Y) & ~DST_METRICS_READ_ONLY))
+#define DST_METRICS_PTR(X)	__DST_METRICS_PTR((X)->_metrics)
+
+static inline bool dst_metrics_read_only(const struct dst_entry *dst)
+{
+	return dst->_metrics & DST_METRICS_READ_ONLY;
+}
+
+extern void __dst_destroy_metrics_generic(struct dst_entry *dst, unsigned long old);
+
+static inline void dst_destroy_metrics_generic(struct dst_entry *dst)
+{
+	unsigned long val = dst->_metrics;
+	if (!(val & DST_METRICS_READ_ONLY))
+		__dst_destroy_metrics_generic(dst, val);
+}
+
+static inline u32 *dst_metrics_write_ptr(struct dst_entry *dst)
+{
+	unsigned long p = dst->_metrics;
+
+	BUG_ON(!p);
+
+	if (p & DST_METRICS_READ_ONLY)
+		return dst->ops->cow_metrics(dst, p);
+	return __DST_METRICS_PTR(p);
+}
+
+/* This may only be invoked before the entry has reached global
+ * visibility.
+ */
+static inline void dst_init_metrics(struct dst_entry *dst,
+				    const u32 *src_metrics,
+				    bool read_only)
+{
+	dst->_metrics = ((unsigned long) src_metrics) |
+		(read_only ? DST_METRICS_READ_ONLY : 0);
+}
+
+static inline void dst_copy_metrics(struct dst_entry *dest, const struct dst_entry *src)
+{
+	u32 *dst_metrics = dst_metrics_write_ptr(dest);
+
+	if (dst_metrics) {
+		u32 *src_metrics = DST_METRICS_PTR(src);
+
+		memcpy(dst_metrics, src_metrics, RTAX_MAX * sizeof(u32));
+	}
+}
+
+static inline u32 *dst_metrics_ptr(struct dst_entry *dst)
+{
+	return DST_METRICS_PTR(dst);
+}
+
+static inline u32
+dst_metric_raw(const struct dst_entry *dst, const int metric)
+{
+	u32 *p = DST_METRICS_PTR(dst);
+
+	return p[metric-1];
+}
+
+static inline u32
+dst_metric(const struct dst_entry *dst, const int metric)
+{
+	WARN_ON_ONCE(metric == RTAX_HOPLIMIT ||
+		     metric == RTAX_ADVMSS ||
+		     metric == RTAX_MTU);
+	return dst_metric_raw(dst, metric);
+}
+
+static inline u32
+dst_metric_advmss(const struct dst_entry *dst)
+{
+	u32 advmss = dst_metric_raw(dst, RTAX_ADVMSS);
+
+	if (!advmss)
+		advmss = dst->ops->default_advmss(dst);
+
+	return advmss;
+}
+
+static inline void dst_metric_set(struct dst_entry *dst, int metric, u32 val)
+{
+	u32 *p = dst_metrics_write_ptr(dst);
+
+	if (p)
+		p[metric-1] = val;
+}
+
+static inline u32
+dst_feature(const struct dst_entry *dst, u32 feature)
+{
+	return dst_metric(dst, RTAX_FEATURES) & feature;
+}
+
+static inline u32 dst_mtu(const struct dst_entry *dst)
+{
+	u32 mtu = dst_metric_raw(dst, RTAX_MTU);
+
+	if (!mtu)
+		mtu = dst->ops->default_mtu(dst);
+
+	return mtu;
+}
+
+/* RTT metrics are stored in milliseconds for user ABI, but used as jiffies */
+static inline unsigned long dst_metric_rtt(const struct dst_entry *dst, int metric)
+{
+	return msecs_to_jiffies(dst_metric(dst, metric));
+}
+
+static inline void set_dst_metric_rtt(struct dst_entry *dst, int metric,
+				      unsigned long rtt)
+{
+	dst_metric_set(dst, metric, jiffies_to_msecs(rtt));
+}
+
+static inline u32
+dst_allfrag(const struct dst_entry *dst)
+{
+	int ret = dst_feature(dst,  RTAX_FEATURE_ALLFRAG);
+	return ret;
+}
+
+static inline int
+dst_metric_locked(const struct dst_entry *dst, int metric)
+{
+	return dst_metric(dst, RTAX_LOCK) & (1<<metric);
+}
+
+static inline void dst_hold(struct dst_entry * dst)
+{
+	/*
+	 * If your kernel compilation stops here, please check
+	 * __pad_to_align_refcnt declaration in struct dst_entry
+	 */
+	BUILD_BUG_ON(offsetof(struct dst_entry, __refcnt) & 63);
+	atomic_inc(&dst->__refcnt);
+}
+
+static inline void dst_use(struct dst_entry *dst, unsigned long time)
+{
+	dst_hold(dst);
+	dst->__use++;
+	dst->lastuse = time;
+}
+
+static inline void dst_use_noref(struct dst_entry *dst, unsigned long time)
+{
+	dst->__use++;
+	dst->lastuse = time;
+}
+
+static inline
+struct dst_entry * dst_clone(struct dst_entry * dst)
+{
+	if (dst)
+		atomic_inc(&dst->__refcnt);
+	return dst;
+}
+
+extern void dst_release(struct dst_entry *dst);
+
+static inline void refdst_drop(unsigned long refdst)
+{
+	if (!(refdst & SKB_DST_NOREF))
+		dst_release((struct dst_entry *)(refdst & SKB_DST_PTRMASK));
+}
+
+/**
+ * skb_dst_drop - drops skb dst
+ * @skb: buffer
+ *
+ * Drops dst reference count if a reference was taken.
+ */
+static inline void skb_dst_drop(struct sk_buff *skb)
+{
+	if (skb->_skb_refdst) {
+		refdst_drop(skb->_skb_refdst);
+		skb->_skb_refdst = 0UL;
+	}
+}
+
+static inline void skb_dst_copy(struct sk_buff *nskb, const struct sk_buff *oskb)
+{
+	nskb->_skb_refdst = oskb->_skb_refdst;
+	if (!(nskb->_skb_refdst & SKB_DST_NOREF))
+		dst_clone(skb_dst(nskb));
+}
+
+/**
+ * skb_dst_force - makes sure skb dst is refcounted
+ * @skb: buffer
+ *
+ * If dst is not yet refcounted, let's do it
+ */
+static inline void skb_dst_force(struct sk_buff *skb)
+{
+	if (skb_dst_is_noref(skb)) {
+		WARN_ON(!rcu_read_lock_held());
+		skb->_skb_refdst &= ~SKB_DST_NOREF;
+		dst_clone(skb_dst(skb));
+	}
+}
+
+
+/**
+ *	__skb_tunnel_rx - prepare skb for rx reinsert
+ *	@skb: buffer
+ *	@dev: tunnel device
+ *
+ *	After decapsulation, packet is going to re-enter (netif_rx()) our stack,
+ *	so make some cleanups. (no accounting done)
+ */
+static inline void __skb_tunnel_rx(struct sk_buff *skb, struct net_device *dev)
+{
+	skb->dev = dev;
+	skb->rxhash = 0;
+	skb_set_queue_mapping(skb, 0);
+	skb_dst_drop(skb);
+	nf_reset(skb);
+}
+
+/**
+ *	skb_tunnel_rx - prepare skb for rx reinsert
+ *	@skb: buffer
+ *	@dev: tunnel device
+ *
+ *	After decapsulation, packet is going to re-enter (netif_rx()) our stack,
+ *	so make some cleanups, and perform accounting.
+ *	Note: this accounting is not SMP safe.
+ */
+static inline void skb_tunnel_rx(struct sk_buff *skb, struct net_device *dev)
+{
+	/* TODO : stats should be SMP safe */
+	dev->stats.rx_packets++;
+	dev->stats.rx_bytes += skb->len;
+	__skb_tunnel_rx(skb, dev);
+}
+
+/* Children define the path of the packet through the
+ * Linux networking.  Thus, destinations are stackable.
+ */
+
+static inline struct dst_entry *skb_dst_pop(struct sk_buff *skb)
+{
+	struct dst_entry *child = dst_clone(skb_dst(skb)->child);
+
+	skb_dst_drop(skb);
+	return child;
+}
+
+extern int dst_discard(struct sk_buff *skb);
+extern void *dst_alloc(struct dst_ops * ops, struct net_device *dev,
+		       int initial_ref, int initial_obsolete, int flags);
+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) {
+		struct neighbour *n;
+
+		rcu_read_lock();
+		n = dst_get_neighbour(dst);
+		neigh_confirm(n);
+		rcu_read_unlock();
+	}
+}
+
+static inline void dst_link_failure(struct sk_buff *skb)
+{
+	struct dst_entry *dst = skb_dst(skb);
+	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)
+{
+	return skb_dst(skb)->output(skb);
+}
+
+/* Input packet from network to transport.  */
+static inline int dst_input(struct sk_buff *skb)
+{
+	return skb_dst(skb)->input(skb);
+}
+
+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);
+
+/* Flags for xfrm_lookup flags argument. */
+enum {
+	XFRM_LOOKUP_ICMP = 1 << 0,
+};
+
+struct flowi;
+#ifndef CONFIG_XFRM
+static inline struct dst_entry *xfrm_lookup(struct net *net,
+					    struct dst_entry *dst_orig,
+					    const struct flowi *fl, struct sock *sk,
+					    int flags)
+{
+	return dst_orig;
+} 
+#else
+extern struct dst_entry *xfrm_lookup(struct net *net, struct dst_entry *dst_orig,
+				     const struct flowi *fl, struct sock *sk,
+				     int flags);
+#endif
+
+#endif /* _NET_DST_H */