Remove the concept of the media-independent link-layer header and replace

it with metadata in the pkb structure.  This is required since UNDI will
want to be able to parse the link-layer header without destroying it.

1 files changed, 116 insertions, 0 deletions

diff --git a/src/net/ethernet.c b/src/net/ethernet.c
new file mode 100644
index 000000000..078719b32
--- /dev/null
+++ b/src/net/ethernet.c
@@ -0,0 +1,116 @@
+/*
+ * 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 <string.h>
+#include <byteswap.h>
+#include <assert.h>
+#include <gpxe/if_ether.h>
+#include <gpxe/netdevice.h>
+#include <gpxe/pkbuff.h>
+#include <gpxe/arp.h>
+
+/** @file
+ *
+ * Ethernet protocol
+ *
+ */
+
+/** Ethernet broadcast MAC address */
+static uint8_t eth_broadcast[] = { 0xff, 0xff, 0xff, 0xff, 0xff, 0xff };
+
+/**
+ * Build Ethernet link-layer header
+ *
+ * @v netdev	Network device
+ * @v pkb	Packet buffer
+ * @ret rc	Return status code
+ *
+ * This constructs the Ethernet link-layer header (destination MAC,
+ * source MAC, network-layer protocol) based on the metadata found in
+ * @c pkb.
+ *
+ * If the destination MAC address cannot be determined, an ARP request
+ * is sent for the requested network-layer address instead.
+ */
+int eth_build_llh ( struct net_device *netdev, struct pk_buff *pkb ) {
+	struct ethhdr *ethhdr = pkb->data;
+	const void *eth_dest;
+	int rc;
+
+	/* Do the easy bits */
+	ethhdr->h_protocol = pkb->net_proto;
+	memcpy ( ethhdr->h_source, netdev->ll_addr,
+		 sizeof ( ethhdr->h_source ) );
+
+	/* Work out the destination MAC address */
+	if ( pkb->flags & PKB_FL_RAW_NET_ADDR ) {
+		eth_dest = pkb->net_addr;
+	} else if ( pkb->flags & PKB_FL_BROADCAST ) {
+		eth_dest = eth_broadcast;
+	} else if ( pkb->flags & PKB_FL_MULTICAST ) {
+		/* IP multicast is a special case; there exists a
+		 * direct mapping from IP address to MAC address
+		 */
+		assert ( pkb->net_proto == htons ( ETH_P_IP ) );
+		ethhdr->h_dest[0] = 0x01;
+		ethhdr->h_dest[1] = 0x00;
+		ethhdr->h_dest[2] = 0x5e;
+		ethhdr->h_dest[3] = *( ( char * ) pkb->net_addr + 1 ) & 0x7f;
+		ethhdr->h_dest[4] = *( ( char * ) pkb->net_addr + 2 );
+		ethhdr->h_dest[5] = *( ( char * ) pkb->net_addr + 3 );
+		eth_dest = ethhdr->h_dest;
+	} else {
+		/* Otherwise, look up the address using ARP */
+		if ( ( rc = arp_resolve ( netdev, pkb, &eth_dest ) ) != 0 )
+			return rc;
+	}
+
+	/* Fill in destination MAC address */
+	memcpy ( ethhdr->h_dest, eth_dest, sizeof ( ethhdr->h_dest ) );
+
+	return 0;
+}
+
+/**
+ * Parse Ethernet link-layer header
+ *
+ * @v netdev	Network device
+ * @v pkb	Packet buffer
+ * @ret rc	Return status code
+ *
+ * This parses the Ethernet link-layer header (destination MAC, source
+ * MAC, network-layer protocol) and fills in the metadata in @c pkb.
+ */
+int eth_parse_llh ( struct net_device *netdev __unused, struct pk_buff *pkb ) {
+	struct ethhdr *ethhdr = pkb->data;
+
+	pkb->net_proto = ethhdr->h_protocol;
+	pkb->flags = PKB_FL_RAW_NET_ADDR;
+	pkb->net_addr_len = sizeof ( ethhdr->h_dest );
+	pkb->net_addr = ethhdr->h_dest;
+
+	if ( memcmp ( ethhdr->h_dest, eth_broadcast,
+		      sizeof ( ethhdr->h_dest ) ) == 0 ) {
+		pkb->flags |= PKB_FL_BROADCAST;
+	} else if ( ethhdr->h_dest[0] & 0x01 ) {
+		pkb->flags |= PKB_FL_MULTICAST;
+	}
+
+	return 0;
+}