[neighbour] Generalise concept of neighbour discovery

Split the protocol-independent portions of arp.c into a separate file
neighbour.c, to allow for sharing of functionality between IPv4+ARP
and IPv6+NDP.

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

3 files changed, 66 insertions, 3 deletions

diff --git a/src/include/ipxe/arp.h b/src/include/ipxe/arp.h
index 00396d821..e30ae6b76 100644
--- a/src/include/ipxe/arp.h
+++ b/src/include/ipxe/arp.h
@@ -11,6 +11,7 @@ FILE_LICENCE ( GPL2_OR_LATER );
 
 #include <ipxe/tables.h>
 #include <ipxe/netdevice.h>
+#include <ipxe/neighbour.h>
 
 /** A network-layer protocol that relies upon ARP */
 struct arp_net_protocol {
@@ -34,9 +35,26 @@ struct arp_net_protocol {
 #define __arp_net_protocol __table_entry ( ARP_NET_PROTOCOLS, 01 )
 
 extern struct net_protocol arp_protocol __net_protocol;
+extern struct neighbour_discovery arp_discovery;
 
-extern int arp_tx ( struct io_buffer *iobuf, struct net_device *netdev,
-		    struct net_protocol *net_protocol, const void *net_dest,
-		    const void *net_source, const void *ll_source );
+/**
+ * Transmit packet, determining link-layer address via ARP
+ *
+ * @v iobuf		I/O buffer
+ * @v netdev		Network device
+ * @v net_protocol	Network-layer protocol
+ * @v net_dest		Destination network-layer address
+ * @v net_source	Source network-layer address
+ * @v ll_source		Source link-layer address
+ * @ret rc		Return status code
+ */
+static inline int arp_tx ( struct io_buffer *iobuf, struct net_device *netdev,
+			   struct net_protocol *net_protocol,
+			   const void *net_dest, const void *net_source,
+			   const void *ll_source ) {
+
+	return neighbour_tx ( iobuf, netdev, net_protocol, net_dest,
+			      &arp_discovery, net_source, ll_source );
+}
 
 #endif /* _IPXE_ARP_H */
diff --git a/src/include/ipxe/errfile.h b/src/include/ipxe/errfile.h
index 801d579b6..83675796c 100644
--- a/src/include/ipxe/errfile.h
+++ b/src/include/ipxe/errfile.h
@@ -214,6 +214,7 @@ FILE_LICENCE ( GPL2_OR_LATER );
 #define ERRFILE_nfs_open		( ERRFILE_NET | 0x00340000 )
 #define ERRFILE_mount			( ERRFILE_NET | 0x00350000 )
 #define ERRFILE_oncrpc_iob		( ERRFILE_NET | 0x00360000 )
+#define ERRFILE_neighbour		( ERRFILE_NET | 0x00370000 )
 
 #define ERRFILE_image		      ( ERRFILE_IMAGE | 0x00000000 )
 #define ERRFILE_elf		      ( ERRFILE_IMAGE | 0x00010000 )
diff --git a/src/include/ipxe/neighbour.h b/src/include/ipxe/neighbour.h
new file mode 100644
index 000000000..5720e8b0f
--- /dev/null
+++ b/src/include/ipxe/neighbour.h
@@ -0,0 +1,44 @@
+#ifndef _IPXE_NEIGHBOUR_H
+#define _IPXE_NEIGHBOUR_H
+
+/** @file
+ *
+ * Neighbour discovery
+ *
+ */
+
+FILE_LICENCE ( GPL2_OR_LATER );
+
+#include <ipxe/netdevice.h>
+
+/** A neighbour discovery protocol */
+struct neighbour_discovery {
+	/** Name */
+	const char *name;
+	/**
+	 * Transmit neighbour discovery request
+	 *
+	 * @v netdev		Network device
+	 * @v net_protocol	Network-layer protocol
+	 * @v net_dest		Destination network-layer address
+	 * @v net_source	Source network-layer address
+	 * @ret rc		Return status code
+	 */
+	int ( * tx_request ) ( struct net_device *netdev,
+			       struct net_protocol *net_protocol,
+			       const void *net_dest, const void *net_source );
+};
+
+extern int neighbour_tx ( struct io_buffer *iobuf, struct net_device *netdev,
+			  struct net_protocol *net_protocol,
+			  const void *net_dest,
+			  struct neighbour_discovery *discovery,
+			  const void *net_source, const void *ll_source );
+extern int neighbour_update ( struct net_device *netdev,
+			      struct net_protocol *net_protocol,
+			      const void *net_dest, const void *ll_dest );
+extern int neighbour_define ( struct net_device *netdev,
+			      struct net_protocol *net_protocol,
+			      const void *net_dest, const void *ll_dest );
+
+#endif /* _IPXE_NEIGHBOUR_H */