1 files changed, 527 insertions, 0 deletions

diff --git a/kernel/include/net/dst.h b/kernel/include/net/dst.h
new file mode 100644
index 000000000..b6a790646
--- /dev/null
+++ b/kernel/include/net/dst.h
@@ -0,0 +1,527 @@
+/*
+ * 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/bug.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 dst_entry	*from;
+#ifdef CONFIG_XFRM
+	struct xfrm_state	*xfrm;
+#else
+	void			*__pad1;
+#endif
+	int			(*input)(struct sk_buff *);
+	int			(*output)(struct sock *sk, struct sk_buff *skb);
+
+	unsigned short		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_FAKE_RTABLE		0x0040
+#define DST_XFRM_TUNNEL		0x0080
+#define DST_XFRM_QUEUE		0x0100
+
+	unsigned short		pending_confirm;
+
+	short			error;
+
+	/* A non-zero value of dst->obsolete forces by-hand validation
+	 * of the route entry.  Positive values are set by the generic
+	 * dst layer to indicate that the entry has been forcefully
+	 * destroyed.
+	 *
+	 * Negative values are used by the implementation layer code to
+	 * force invocation of the dst_ops->check() method.
+	 */
+	short			obsolete;
+#define DST_OBSOLETE_NONE	0
+#define DST_OBSOLETE_DEAD	2
+#define DST_OBSOLETE_FORCE_CHK	-1
+#define DST_OBSOLETE_KILL	-2
+	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[2];
+#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;
+	union {
+		struct dst_entry	*next;
+		struct rtable __rcu	*rt_next;
+		struct rt6_info		*rt6_next;
+		struct dn_route __rcu	*dn_next;
+	};
+};
+
+u32 *dst_cow_metrics_generic(struct dst_entry *dst, unsigned long old);
+extern const u32 dst_default_metrics[];
+
+#define DST_METRICS_READ_ONLY		0x1UL
+#define DST_METRICS_FORCE_OVERWRITE	0x2UL
+#define DST_METRICS_FLAGS		0x3UL
+#define __DST_METRICS_PTR(Y)	\
+	((u32 *)((Y) & ~DST_METRICS_FLAGS))
+#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;
+}
+
+static inline void dst_metrics_set_force_overwrite(struct dst_entry *dst)
+{
+	dst->_metrics |= DST_METRICS_FORCE_OVERWRITE;
+}
+
+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)
+{
+	return dst->ops->mtu(dst);
+}
+
+/* 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 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;
+}
+
+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
+ *	@net: netns for packet i/o
+ *
+ *	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,
+				   struct net *net)
+{
+	skb->dev = dev;
+
+	/*
+	 * Clear hash so that we can recalulate the hash for the
+	 * encapsulated packet, unless we have already determine the hash
+	 * over the L4 4-tuple.
+	 */
+	skb_clear_hash_if_not_l4(skb);
+	skb_set_queue_mapping(skb, 0);
+	skb_scrub_packet(skb, !net_eq(net, dev_net(dev)));
+}
+
+/**
+ *	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,
+				 struct net *net)
+{
+	/* TODO : stats should be SMP safe */
+	dev->stats.rx_packets++;
+	dev->stats.rx_bytes += skb->len;
+	__skb_tunnel_rx(skb, dev, net);
+}
+
+/* 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;
+}
+
+int dst_discard_sk(struct sock *sk, struct sk_buff *skb);
+static inline int dst_discard(struct sk_buff *skb)
+{
+	return dst_discard_sk(skb->sk, skb);
+}
+void *dst_alloc(struct dst_ops *ops, struct net_device *dev, int initial_ref,
+		int initial_obsolete, unsigned short flags);
+void __dst_free(struct dst_entry *dst);
+struct dst_entry *dst_destroy(struct dst_entry *dst);
+
+static inline void dst_free(struct dst_entry *dst)
+{
+	if (dst->obsolete > 0)
+		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)
+{
+	dst->pending_confirm = 1;
+}
+
+static inline int dst_neigh_output(struct dst_entry *dst, struct neighbour *n,
+				   struct sk_buff *skb)
+{
+	struct hh_cache *hh;
+
+	if (dst->pending_confirm) {
+		unsigned long now = jiffies;
+
+		dst->pending_confirm = 0;
+		/* avoid dirtying neighbour */
+		if (n->confirmed != now)
+			n->confirmed = now;
+	}
+
+	hh = &n->hh;
+	if ((n->nud_state & NUD_CONNECTED) && hh->hh_len)
+		return neigh_hh_output(hh, skb);
+	else
+		return n->output(n, skb);
+}
+
+static inline struct neighbour *dst_neigh_lookup(const struct dst_entry *dst, const void *daddr)
+{
+	struct neighbour *n = dst->ops->neigh_lookup(dst, NULL, daddr);
+	return IS_ERR(n) ? NULL : n;
+}
+
+static inline struct neighbour *dst_neigh_lookup_skb(const struct dst_entry *dst,
+						     struct sk_buff *skb)
+{
+	struct neighbour *n =  dst->ops->neigh_lookup(dst, skb, NULL);
+	return IS_ERR(n) ? NULL : n;
+}
+
+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_sk(struct sock *sk, struct sk_buff *skb)
+{
+	return skb_dst(skb)->output(sk, skb);
+}
+static inline int dst_output(struct sk_buff *skb)
+{
+	return dst_output_sk(skb->sk, 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;
+}
+
+void dst_init(void);
+
+/* Flags for xfrm_lookup flags argument. */
+enum {
+	XFRM_LOOKUP_ICMP = 1 << 0,
+	XFRM_LOOKUP_QUEUE = 1 << 1,
+	XFRM_LOOKUP_KEEP_DST_REF = 1 << 2,
+};
+
+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;
+}
+
+static inline struct dst_entry *xfrm_lookup_route(struct net *net,
+						  struct dst_entry *dst_orig,
+						  const struct flowi *fl,
+						  struct sock *sk,
+						  int flags)
+{
+	return dst_orig;
+}
+
+static inline struct xfrm_state *dst_xfrm(const struct dst_entry *dst)
+{
+	return NULL;
+}
+
+#else
+struct dst_entry *xfrm_lookup(struct net *net, struct dst_entry *dst_orig,
+			      const struct flowi *fl, struct sock *sk,
+			      int flags);
+
+struct dst_entry *xfrm_lookup_route(struct net *net, struct dst_entry *dst_orig,
+				    const struct flowi *fl, struct sock *sk,
+				    int flags);
+
+/* skb attached with this dst needs transformation if dst->xfrm is valid */
+static inline struct xfrm_state *dst_xfrm(const struct dst_entry *dst)
+{
+	return dst->xfrm;
+}
+#endif
+
+#endif /* _NET_DST_H */