[Settings] Migrate DHCP and NVO code to the new settings API (untested)

src/net/dhcppkt.c

@@ -0,0 +1,186 @@
+/*
+ * 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/netdevice.h>
+#include <gpxe/dhcp.h>
+#include <gpxe/dhcpopts.h>
+#include <gpxe/dhcppkt.h>
+
+/** @file
+ *
+ * DHCP packets
+ *
+ */
+
+/** A dedicated field within a DHCP packet */
+struct dhcp_packet_field {
+	/** Settings tag number */
+	unsigned int tag;
+	/** Offset within DHCP packet */
+	uint16_t offset;
+	/** Length of field */
+	uint16_t len;
+};
+
+/** Declare a dedicated field within a DHCP packet
+ *
+ * @v _tag		Settings tag number
+ * @v _field		Field name
+ */
+#define DHCP_PACKET_FIELD( _tag, _field ) {				\
+		.tag = (_tag),						\
+		.offset = offsetof ( struct dhcphdr, _field ),		\
+		.len = sizeof ( ( ( struct dhcphdr * ) 0 )->_field ),	\
+	}
+
+/** Dedicated fields within a DHCP packet */
+static struct dhcp_packet_field dhcp_packet_fields[] = {
+	DHCP_PACKET_FIELD ( DHCP_EB_YIADDR, yiaddr ),
+	DHCP_PACKET_FIELD ( DHCP_EB_SIADDR, siaddr ),
+	DHCP_PACKET_FIELD ( DHCP_TFTP_SERVER_NAME, sname ),
+	DHCP_PACKET_FIELD ( DHCP_BOOTFILE_NAME, file ),
+};
+
+/**
+ * Get address of a DHCP packet field
+ *
+ * @v dhcphdr		DHCP packet header
+ * @v field		DHCP packet field
+ * @ret data		Packet field data
+ */
+static inline void * dhcp_packet_field ( struct dhcphdr *dhcphdr,
+					 struct dhcp_packet_field *field ) {
+	return ( ( ( void * ) dhcphdr ) + field->offset );
+}
+
+/**
+ * Find DHCP packet field corresponding to settings tag number
+ *
+ * @v tag		Settings tag number
+ * @ret field		DHCP packet field, or NULL
+ */
+static struct dhcp_packet_field *
+find_dhcp_packet_field ( unsigned int tag ) {
+	struct dhcp_packet_field *field;
+	unsigned int i;
+
+	for ( i = 0 ; i < ( sizeof ( dhcp_packet_fields ) /
+			    sizeof ( dhcp_packet_fields[0] ) ) ; i++ ) {
+		field = &dhcp_packet_fields[i];
+		if ( field->tag == tag )
+			return field;
+	}
+	return NULL;
+}
+				    
+/**
+ * Store value of DHCP packet setting
+ *
+ * @v settings		Settings block
+ * @v tag		Setting tag number
+ * @v data		Setting data, or NULL to clear setting
+ * @v len		Length of setting data
+ * @ret rc		Return status code
+ */
+static int dhcppkt_store ( struct settings *settings, unsigned int tag,
+			   const void *data, size_t len ) {
+	struct dhcp_packet *dhcppkt =
+		container_of ( settings, struct dhcp_packet, settings );
+	struct dhcp_packet_field *field;
+	int rc;
+
+	/* If this is a special field, fill it in */
+	if ( ( field = find_dhcp_packet_field ( tag ) ) != NULL ) {
+		if ( len > field->len )
+			return -ENOSPC;
+		memcpy ( dhcp_packet_field ( dhcppkt->dhcphdr, field ),
+			 data, len );
+		return 0;
+	}
+
+	/* Otherwise, use the generic options block */
+	rc = dhcpopt_store ( &dhcppkt->options, tag, data, len );
+
+	/* Update our used-length field */
+	dhcppkt->len = ( offsetof ( struct dhcphdr, options ) +
+			 dhcppkt->options.len );
+
+	return rc;
+}
+
+/**
+ * Fetch value of DHCP packet setting
+ *
+ * @v settings		Settings block
+ * @v tag		Setting tag number
+ * @v data		Buffer to fill with setting data
+ * @v len		Length of buffer
+ * @ret len		Length of setting data, or negative error
+ */
+static int dhcppkt_fetch ( struct settings *settings, unsigned int tag,
+			   void *data, size_t len ) {
+	struct dhcp_packet *dhcppkt =
+		container_of ( settings, struct dhcp_packet, settings );
+	struct dhcp_packet_field *field;
+	
+	/* If this is a special field, return it */
+	if ( ( field = find_dhcp_packet_field ( tag ) ) != NULL ) {
+		if ( len > field->len )
+			len = field->len;
+		memcpy ( data,
+			 dhcp_packet_field ( dhcppkt->dhcphdr, field ), len );
+		return field->len;
+	}
+
+	/* Otherwise, use the generic options block */
+	return dhcpopt_fetch ( &dhcppkt->options, tag, data, len );
+}
+
+/** DHCP settings operations */
+static struct settings_operations dhcppkt_settings_operations = {
+	.store = dhcppkt_store,
+	.fetch = dhcppkt_fetch,
+};
+
+/**
+ * Initialise prepopulated DHCP packet
+ *
+ * @v dhcppkt		Uninitialised DHCP packet
+ * @v refcnt		Reference counter of containing object, or NULL
+ * @v data		Memory for DHCP packet data
+ * @v max_len		Length of memory for DHCP packet data
+ *
+ * The memory content must already be filled with valid DHCP options.
+ * A zeroed block counts as a block of valid DHCP options.
+ */
+void dhcppkt_init ( struct dhcp_packet *dhcppkt, struct refcnt *refcnt,
+		    void *data, size_t len ) {
+	dhcppkt->dhcphdr = data;
+	dhcppkt->max_len = len;
+	dhcpopt_init ( &dhcppkt->options, &dhcppkt->dhcphdr->options,
+		       ( len - offsetof ( struct dhcphdr, options ) ) );
+	dhcppkt->len = ( offsetof ( struct dhcphdr, options ) +
+			 dhcppkt->options.len );
+	settings_init ( &dhcppkt->settings, &dhcppkt_settings_operations,
+			refcnt, "dhcp" );
+}