[eapol] Add basic support for 802.1X EAP over LANs

EAPOL is a container protocol that can wrap either EAP packets or
802.11 EAPOL-Key frames. For cleanliness' sake, add a stub that strips
the framing and sends packets off to the appropriate handler if it
is compiled in.

Signed-off-by: Marty Connor <mdc@etherboot.org>

src/net/eapol.c

@@ -0,0 +1,85 @@
+/*
+ * Copyright (c) 2009 Joshua Oreman <oremanj@rwcr.net>.
+ *
+ * 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.
+ */
+
+FILE_LICENCE ( GPL2_OR_LATER );
+
+/** @file
+ *
+ * 802.1X Extensible Authentication Protocol over LANs demultiplexer
+ *
+ */
+
+#include <gpxe/netdevice.h>
+#include <gpxe/iobuf.h>
+#include <gpxe/if_ether.h>
+#include <gpxe/eapol.h>
+#include <errno.h>
+#include <byteswap.h>
+
+/**
+ * Receive EAPOL network-layer packet
+ *
+ * @v iob	I/O buffer
+ * @v netdev	Network device
+ * @v ll_source	Link-layer source address
+ *
+ * This function takes ownership of the I/O buffer passed to it.
+ */
+static int eapol_rx ( struct io_buffer *iob, struct net_device *netdev,
+		      const void *ll_source )
+{
+	struct eapol_frame *eapol = iob->data;
+	struct eapol_handler *handler;
+
+	if ( iob_len ( iob ) < EAPOL_HDR_LEN ) {
+		free_iob ( iob );
+		return -EINVAL;
+	}
+
+	for_each_table_entry ( handler, EAPOL_HANDLERS ) {
+		if ( handler->type == eapol->type ) {
+			iob_pull ( iob, EAPOL_HDR_LEN );
+			return handler->rx ( iob, netdev, ll_source );
+		}
+	}
+
+	free_iob ( iob );
+	return -( ENOTSUP | ( ( eapol->type & 0x1f ) << 8 ) );
+}
+
+/**
+ * Transcribe EAPOL network-layer address
+ *
+ * @v net_addr	Network-layer address
+ * @ret str	String representation of network-layer address
+ *
+ * EAPOL doesn't have network-layer addresses, so we just return the
+ * string @c "<EAPOL>".
+ */
+static const char * eapol_ntoa ( const void *net_addr __unused )
+{
+	return "<EAPOL>";
+}
+
+/** EAPOL network protocol */
+struct net_protocol eapol_protocol __net_protocol = {
+	.name = "EAPOL",
+	.rx = eapol_rx,
+	.ntoa = eapol_ntoa,
+	.net_proto = htons ( ETH_P_EAPOL ),
+};