[Settings] Remove assumption that all settings have DHCP tag values

Allow for settings to be described by something other than a DHCP option
tag if desirable.  Currently used only for the MAC address setting.

Separate out fake DHCP packet creation code from dhcp.c to fakedhcp.c.

Remove notion of settings from dhcppkt.c.

Rationalise dhcp.c to use settings API only for final registration of the
DHCP options, rather than using {store,fetch}_setting throughout.

1 files changed, 205 insertions, 0 deletions

diff --git a/src/net/fakedhcp.c b/src/net/fakedhcp.c
new file mode 100644
index 00000000..c3054db1
--- /dev/null
+++ b/src/net/fakedhcp.c
@@ -0,0 +1,205 @@
+/*
+ * 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 <stdint.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <errno.h>
+#include <string.h>
+#include <gpxe/settings.h>
+#include <gpxe/netdevice.h>
+#include <gpxe/dhcppkt.h>
+#include <gpxe/fakedhcp.h>
+
+/** @file
+ *
+ * Fake DHCP packets
+ *
+ */
+
+/**
+ * Copy settings to DHCP packet
+ *
+ * @v dest		Destination DHCP packet
+ * @v source		Source settings block
+ * @v encapsulator	Encapsulating setting tag number, or zero
+ * @ret rc		Return status code
+ */
+static int copy_encap_settings ( struct dhcp_packet *dest,
+				 struct settings *source,
+				 unsigned int encapsulator ) {
+	struct setting setting = { .name = "" };
+	unsigned int subtag;
+	unsigned int tag;
+	int len;
+	int check_len;
+	int rc;
+
+	for ( subtag = DHCP_MIN_OPTION; subtag <= DHCP_MAX_OPTION; subtag++ ) {
+		tag = DHCP_ENCAP_OPT ( encapsulator, subtag );
+		switch ( tag ) {
+		case DHCP_EB_ENCAP:
+		case DHCP_VENDOR_ENCAP:
+			/* Process encapsulated settings */
+			if ( ( rc = copy_encap_settings ( dest, source,
+							  tag ) ) != 0 )
+				return rc;
+			break;
+		default:
+			/* Copy setting, if present */
+			setting.tag = tag;
+			len = fetch_setting_len ( source, &setting );
+			if ( len < 0 )
+				break;
+			{
+				char buf[len];
+
+				check_len = fetch_setting ( source, &setting,
+							    buf, sizeof (buf));
+				assert ( check_len == len );
+				if ( ( rc = dhcppkt_store ( dest, tag, buf,
+							    sizeof(buf) )) !=0)
+					return rc;
+			}
+			break;
+		}
+	}
+
+	return 0;
+}
+
+/**
+ * Copy settings to DHCP packet
+ *
+ * @v dest		Destination DHCP packet
+ * @v source		Source settings block
+ * @ret rc		Return status code
+ */
+static int copy_settings ( struct dhcp_packet *dest,
+			   struct settings *source ) {
+	return copy_encap_settings ( dest, source, 0 );
+}
+
+/**
+ * Create fake DHCPDISCOVER packet
+ *
+ * @v netdev		Network device
+ * @v data		Buffer for DHCP packet
+ * @v max_len		Size of DHCP packet buffer
+ * @ret rc		Return status code
+ *
+ * Used by external code.
+ */
+int create_fakedhcpdiscover ( struct net_device *netdev,
+			      void *data, size_t max_len ) {
+	struct dhcp_packet dhcppkt;
+	int rc;
+
+	if ( ( rc = create_dhcp_request ( &dhcppkt, netdev, NULL, data,
+					  max_len ) ) != 0 ) {
+		DBG ( "Could not create DHCPDISCOVER: %s\n",
+		      strerror ( rc ) );
+		return rc;
+	}
+
+	return 0;
+}
+
+/**
+ * Create fake DHCPACK packet
+ *
+ * @v netdev		Network device
+ * @v data		Buffer for DHCP packet
+ * @v max_len		Size of DHCP packet buffer
+ * @ret rc		Return status code
+ *
+ * Used by external code.
+ */
+int create_fakedhcpack ( struct net_device *netdev,
+			 void *data, size_t max_len ) {
+	struct dhcp_packet dhcppkt;
+	int rc;
+
+	/* Create base DHCPACK packet */
+	if ( ( rc = create_dhcp_packet ( &dhcppkt, netdev, DHCPACK, NULL,
+					 data, max_len ) ) != 0 ) {
+		DBG ( "Could not create DHCPACK: %s\n", strerror ( rc ) );
+		return rc;
+	}
+
+	/* Merge in globally-scoped settings, then netdev-specific
+	 * settings.  Do it in this order so that netdev-specific
+	 * settings take precedence regardless of stated priorities.
+	 */
+	if ( ( rc = copy_settings ( &dhcppkt, NULL ) ) != 0 ) {
+		DBG ( "Could not set DHCPACK global settings: %s\n",
+		      strerror ( rc ) );
+		return rc;
+	}
+	if ( ( rc = copy_settings ( &dhcppkt,
+				    netdev_settings ( netdev ) ) ) != 0 ) {
+		DBG ( "Could not set DHCPACK netdev settings: %s\n",
+		      strerror ( rc ) );
+		return rc;
+	}
+
+	return 0;
+}
+
+/**
+ * Create ProxyDHCPACK packet
+ *
+ * @v netdev		Network device
+ * @v data		Buffer for DHCP packet
+ * @v max_len		Size of DHCP packet buffer
+ * @ret rc		Return status code
+ *
+ * Used by external code.
+ */
+int create_fakeproxydhcpack ( struct net_device *netdev,
+			      void *data, size_t max_len ) {
+	struct dhcp_packet dhcppkt;
+	struct settings *settings;
+	int rc;
+
+	/* Identify ProxyDHCP settings */
+	settings = find_settings ( PROXYDHCP_SETTINGS_NAME );
+
+	/* No ProxyDHCP settings => return empty block */
+	if ( ! settings ) {
+		memset ( data, 0, max_len );
+		return 0;
+	}
+
+	/* Create base DHCPACK packet */
+	if ( ( rc = create_dhcp_packet ( &dhcppkt, netdev, DHCPACK, NULL,
+					 data, max_len ) ) != 0 ) {
+		DBG ( "Could not create ProxyDHCPACK: %s\n",
+		      strerror ( rc ) );
+		return rc;
+	}
+
+	/* Merge in ProxyDHCP options */
+	if ( ( rc = copy_settings ( &dhcppkt, settings ) ) != 0 ) {
+		DBG ( "Could not set ProxyDHCPACK settings: %s\n",
+		      strerror ( rc ) );
+		return rc;
+	}
+
+	return 0;
+}