[neighbour] Add nstat() function to print out neighbour table

Signed-off-by: Michael Brown <mcb30@ipxe.org>

src/include/ipxe/neighbour.h

@@ -9,7 +9,11 @@
 
 FILE_LICENCE ( GPL2_OR_LATER );
 
+#include <stdint.h>
+#include <ipxe/refcnt.h>
+#include <ipxe/list.h>
 #include <ipxe/netdevice.h>
+#include <ipxe/retry.h>
 
 /** A neighbour discovery protocol */
 struct neighbour_discovery {
@@ -29,6 +33,46 @@ struct neighbour_discovery {
 			       const void *net_dest, const void *net_source );
 };
 
+/** A neighbour cache entry */
+struct neighbour {
+	/** Reference count */
+	struct refcnt refcnt;
+	/** List of neighbour cache entries */
+	struct list_head list;
+
+	/** Network device */
+	struct net_device *netdev;
+	/** Network-layer protocol */
+	struct net_protocol *net_protocol;
+	/** Network-layer destination address */
+	uint8_t net_dest[MAX_NET_ADDR_LEN];
+	/** Link-layer destination address */
+	uint8_t ll_dest[MAX_LL_ADDR_LEN];
+
+	/** Neighbour discovery protocol (if any) */
+	struct neighbour_discovery *discovery;
+	/** Network-layer source address (if any) */
+	uint8_t net_source[MAX_NET_ADDR_LEN];
+	/** Retransmission timer */
+	struct retry_timer timer;
+
+	/** Pending I/O buffers */
+	struct list_head tx_queue;
+};
+
+/**
+ * Test if neighbour cache entry has a valid link-layer address
+ *
+ * @v neighbour		Neighbour cache entry
+ * @ret has_ll_dest	Neighbour cache entry has a valid link-layer address
+ */
+static inline __attribute__ (( always_inline )) int
+neighbour_has_ll_dest ( struct neighbour *neighbour ) {
+	return ( ! timer_running ( &neighbour->timer ) );
+}
+
+extern struct list_head neighbours;
+
 extern int neighbour_tx ( struct io_buffer *iobuf, struct net_device *netdev,
 			  struct net_protocol *net_protocol,
 			  const void *net_dest,

src/include/usr/neighmgmt.h

@@ -0,0 +1,14 @@
+#ifndef _USR_NEIGHMGMT_H
+#define _USR_NEIGHMGMT_H
+
+/** @file
+ *
+ * Neighbour management
+ *
+ */
+
+FILE_LICENCE ( GPL2_OR_LATER );
+
+extern void nstat ( void );
+
+#endif /* _USR_NEIGHMGMT_H */