[pxe] Split out platform-independent portions of cachedhcp.c

Split out the portions of cachedhcp.c that can be shared between BIOS
and UEFI (both of which can provide a buffer containing a previously
obtained DHCP packet, and neither of which provide a means to
determine the length of this DHCP packet).

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

1 files changed, 158 insertions, 0 deletions

diff --git a/src/core/cachedhcp.c b/src/core/cachedhcp.c
new file mode 100644
index 00000000..0e7da4bf
--- /dev/null
+++ b/src/core/cachedhcp.c
@@ -0,0 +1,158 @@
+/*
+ * Copyright (C) 2013 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., 51 Franklin Street, Fifth Floor, Boston, MA
+ * 02110-1301, USA.
+ *
+ * You can also choose to distribute this program under the terms of
+ * the Unmodified Binary Distribution Licence (as given in the file
+ * COPYING.UBDL), provided that you have satisfied its requirements.
+ */
+
+FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
+
+#include <stdint.h>
+#include <stdlib.h>
+#include <errno.h>
+#include <ipxe/dhcppkt.h>
+#include <ipxe/init.h>
+#include <ipxe/netdevice.h>
+#include <ipxe/cachedhcp.h>
+
+/** @file
+ *
+ * Cached DHCP packet
+ *
+ */
+
+/** Cached DHCPACK */
+static struct dhcp_packet *cached_dhcpack;
+
+/** Colour for debug messages */
+#define colour &cached_dhcpack
+
+/**
+ * Record cached DHCPACK
+ *
+ * @v data		DHCPACK packet buffer
+ * @v max_len		Maximum possible length
+ * @ret rc		Return status code
+ */
+int cachedhcp_record ( userptr_t data, size_t max_len ) {
+	struct dhcp_packet *dhcppkt;
+	struct dhcp_packet *tmp;
+	struct dhcphdr *dhcphdr;
+	size_t len;
+
+	/* Allocate and populate DHCP packet */
+	dhcppkt = zalloc ( sizeof ( *dhcppkt ) + max_len );
+	if ( ! dhcppkt ) {
+		DBGC ( colour, "CACHEDHCP could not allocate copy\n" );
+		return -ENOMEM;
+	}
+	dhcphdr = ( ( ( void * ) dhcppkt ) + sizeof ( *dhcppkt ) );
+	copy_from_user ( dhcphdr, data, 0, max_len );
+	dhcppkt_init ( dhcppkt, dhcphdr, max_len );
+
+	/* Shrink packet to required length.  If reallocation fails,
+	 * just continue to use the original packet and waste the
+	 * unused space.
+	 */
+	len = dhcppkt_len ( dhcppkt );
+	assert ( len <= max_len );
+	tmp = realloc ( dhcppkt, ( sizeof ( *dhcppkt ) + len ) );
+	if ( tmp )
+		dhcppkt = tmp;
+
+	/* Reinitialise packet at new address */
+	dhcphdr = ( ( ( void * ) dhcppkt ) + sizeof ( *dhcppkt ) );
+	dhcppkt_init ( dhcppkt, dhcphdr, len );
+
+	/* Store as cached DHCPACK, and mark original copy as consumed */
+	DBGC ( colour, "CACHEDHCP found cached DHCPACK at %#08lx+%#zx/%#zx\n",
+	       user_to_phys ( data, 0 ), len, max_len );
+	cached_dhcpack = dhcppkt;
+
+	return 0;
+}
+
+/**
+ * Cached DHCPACK startup function
+ *
+ */
+static void cachedhcp_startup ( void ) {
+
+	/* If cached DHCP packet was not claimed by any network device
+	 * during startup, then free it.
+	 */
+	if ( cached_dhcpack ) {
+		DBGC ( colour, "CACHEDHCP freeing unclaimed cached DHCPACK\n" );
+		dhcppkt_put ( cached_dhcpack );
+		cached_dhcpack = NULL;
+	}
+}
+
+/** Cached DHCPACK startup function */
+struct startup_fn cachedhcp_startup_fn __startup_fn ( STARTUP_LATE ) = {
+	.name = "cachedhcp",
+	.startup = cachedhcp_startup,
+};
+
+/**
+ * Apply cached DHCPACK to network device, if applicable
+ *
+ * @v netdev		Network device
+ * @ret rc		Return status code
+ */
+static int cachedhcp_probe ( struct net_device *netdev ) {
+	struct ll_protocol *ll_protocol = netdev->ll_protocol;
+	int rc;
+
+	/* Do nothing unless we have a cached DHCPACK */
+	if ( ! cached_dhcpack )
+		return 0;
+
+	/* Do nothing unless cached DHCPACK's MAC address matches this
+	 * network device.
+	 */
+	if ( memcmp ( netdev->ll_addr, cached_dhcpack->dhcphdr->chaddr,
+		      ll_protocol->ll_addr_len ) != 0 ) {
+		DBGC ( colour, "CACHEDHCP cached DHCPACK does not match %s\n",
+		       netdev->name );
+		return 0;
+	}
+	DBGC ( colour, "CACHEDHCP cached DHCPACK is for %s\n", netdev->name );
+
+	/* Register as DHCP settings for this network device */
+	if ( ( rc = register_settings ( &cached_dhcpack->settings,
+					netdev_settings ( netdev ),
+					DHCP_SETTINGS_NAME ) ) != 0 ) {
+		DBGC ( colour, "CACHEDHCP could not register settings: %s\n",
+		       strerror ( rc ) );
+		return rc;
+	}
+
+	/* Claim cached DHCPACK */
+	dhcppkt_put ( cached_dhcpack );
+	cached_dhcpack = NULL;
+
+	return 0;
+}
+
+/** Cached DHCP packet network device driver */
+struct net_driver cachedhcp_driver __net_driver = {
+	.name = "cachedhcp",
+	.probe = cachedhcp_probe,
+};