[Settings] Add per-netdevice settings block

Add a configuration settings block for each net device.  This will
provide the parent scope for settings applicable only to that network
device (e.g. non-volatile options stored on the NIC, options obtained via
DHCP, etc.).

Expose the MAC address as a setting.

src/net/netdev_settings.c

@@ -0,0 +1,95 @@
+/*
+ * Copyright (C) 2008 Michael Brown <mbrown@fensystems.co.uk>.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of the
+ * License, or any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+#include <string.h>
+#include <errno.h>
+#include <gpxe/dhcp.h>
+#include <gpxe/settings.h>
+#include <gpxe/netdevice.h>
+
+/** @file
+ *
+ * Network device configuration settings
+ *
+ */
+
+/**
+ * Store value of network device setting
+ *
+ * @v settings		Settings block
+ * @v tag		Setting tag number
+ * @v data		Setting data, or NULL to clear setting
+ * @v len		Length of setting data
+ * @ret rc		Return status code
+ */
+static int netdev_store ( struct settings *settings, unsigned int tag,
+			  const void *data, size_t len ) {
+	struct net_device *netdev =
+		container_of ( settings, struct net_device, settings );
+
+	switch ( tag ) {
+	case DHCP_EB_MAC:
+		if ( len != netdev->ll_protocol->ll_addr_len )
+			return -EINVAL;
+		memcpy ( netdev->ll_addr, data, len );
+		return 0;
+	default :
+		return simple_settings_store ( settings, tag, data, len );
+	}
+}
+
+/**
+ * Fetch value of network device setting
+ *
+ * @v settings		Settings block
+ * @v tag		Setting tag number
+ * @v data		Setting data, or NULL to clear setting
+ * @v len		Length of setting data
+ * @ret rc		Return status code
+ */
+static int netdev_fetch ( struct settings *settings, unsigned int tag,
+			  void *data, size_t len ) {
+	struct net_device *netdev =
+		container_of ( settings, struct net_device, settings );
+
+	switch ( tag ) {
+	case DHCP_EB_MAC:
+		if ( len > netdev->ll_protocol->ll_addr_len )
+			len = netdev->ll_protocol->ll_addr_len;
+		memcpy ( data, netdev->ll_addr, len );
+		return netdev->ll_protocol->ll_addr_len;
+	default :
+		return simple_settings_fetch ( settings, tag, data, len );
+	}
+}
+
+/** Network device configuration settings operations */
+struct settings_operations netdev_settings_operations = {
+	.store = netdev_store,
+	.fetch = netdev_fetch,
+};
+
+/** Network device named settings */
+struct named_setting netdev_named_settings[] __named_setting = {
+	{
+		.name = "mac",
+		.description = "MAC address",
+		.tag = DHCP_EB_MAC,
+		.type = &setting_type_hex,
+	},
+};