First sketch of a new net device API.

src/net/netdevice.c

@@ -0,0 +1,163 @@
+/*
+ * Copyright (C) 2006 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 <stdint.h>
+#include <byteswap.h>
+#include <errno.h>
+#include <gpxe/if_ether.h>
+#include <gpxe/pkbuff.h>
+#include <gpxe/netdevice.h>
+
+/** @file
+ *
+ * Network devices and network interfaces
+ *
+ */
+
+/** List of all registered network devices */
+static LIST_HEAD ( net_devices );
+
+/**
+ * Register network device
+ *
+ * @v netdev	Network device
+ * @ret rc	Return status code
+ *
+ * Adds the network device to the list of network devices.
+ */
+int register_netdevice ( struct net_device *netdev ) {
+	list_add ( &netdev->devices, &net_devices );
+	return 0;
+}
+
+/**
+ * Unregister network device
+ *
+ * @v netdev	Network device
+ *
+ * Removes the network device from the list of network devices.
+ */
+void unregister_netdevice ( struct net_device *netdev ) {
+	list_del ( &netdev->devices );
+}
+
+/**
+ * Transmit packet via network device
+ *
+ * @v netdev	Network device
+ * @v pkb	Packet buffer
+ * @ret rc	Return status code
+ *
+ * Transmits the packet via the network device.  The @c pkb link-layer
+ * metadata must already have been filled in, and space for the
+ * link-layer header must already be present in the packet buffer.
+ */
+int netdev_send ( struct net_device *netdev, struct pk_buff *pkb ) {
+	int rc;
+
+	if ( pkb->net_proto != ETH_P_RAW ) {
+		if ( ( rc = netdev->build_llh ( netdev, pkb ) ) != 0 )
+			return rc;
+	}
+	return netdev->transmit ( netdev, pkb );
+}
+
+/**
+ * Poll for packet on network device
+ *
+ * @v netdev	Network device
+ * @v pkb	Packet buffer
+ * @ret rc	Return status code
+ *
+ * Polls the network device for a packet.  If a packet is available,
+ * it will be added to the packet buffer, and the link-layer metadata
+ * fields in @c pkb will be filled in.
+ */
+int netdev_poll ( struct net_device *netdev, struct pk_buff *pkb ) {
+	int rc;
+
+	if ( ( rc = netdev->poll ( netdev, pkb ) ) != 0 )
+		return rc;
+	return netdev->parse_llh ( netdev, pkb );
+}
+
+/**
+ * Transmit packet via network interface
+ *
+ * @v netif	Network interface
+ * @v pkb	Packet buffer
+ * @ret rc	Return status code
+ *
+ * Transmits the packet via the network interface.  The packet must
+ * start with a network-layer header (e.g. an IP header, for an IP
+ * interface).  The packet contents are undefined on return.
+ */
+int netif_send ( struct net_interface *netif, struct pk_buff *pkb ) {
+	struct net_device *netdev = netif->netdev;
+	int rc;
+
+	if ( ( rc = netif->add_llh_metadata ( netif, pkb ) ) != 0 )
+		return rc;
+	pkb_push ( pkb, netdev->ll_hlen );
+	return netdev_send ( netdev, pkb );
+}
+
+/**
+ * Process received packet
+ *
+ * @v netif	Network interface
+ * @v pkb	Packet buffer
+ * @ret rc	Return status code
+ *
+ * Processes a packet received via netdev_poll().  The interface
+ * corresponding to the network-layer protocol is identified, the
+ * link-layer header is stripped from the packet and the packet is
+ * passed to the net_interface::rx_packet() method.
+ */
+int netdev_rx_packet ( struct net_device *netdev, struct pk_buff *pkb ) {
+	struct net_interface *netif;
+
+	netif = netdev_find_netif ( netdev, pkb->net_proto );
+	if ( ! netif )
+		return -EAFNOSUPPORT;
+
+	pkb_pull ( pkb, netdev->ll_hlen );
+	return netif->rx_packet ( netif, pkb );
+}
+
+/**
+ * Poll for packet on all network devices
+ *
+ * @v pkb	Packet buffer
+ * @ret netdev	Network device
+ * @ret rc	Return status code
+ *
+ * Polls all network devices for a packet.  If a packet is available
+ * on any interface, @c netdev will be filled in and the packet will
+ * be received as per netdev_poll().
+ */
+int net_poll ( struct pk_buff *pkb, struct net_device **netdev ) {
+	int rc;
+
+	list_for_each_entry ( (*netdev), &net_devices, devices ) {
+		if ( ( rc = netdev_poll ( *netdev, pkb ) ) == 0 )
+			return rc;
+	}
+
+	return -EAGAIN;
+}