[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, 181 insertions, 273 deletions

diff --git a/src/core/settings.c b/src/core/settings.c
index 809779ae..b793ae68 100644
--- a/src/core/settings.c
+++ b/src/core/settings.c
@@ -35,43 +35,24 @@
  *
  */
 
+/** Registered settings */
+static struct setting settings[0]
+	__table_start ( struct setting, settings );
+static struct setting settings_end[0]
+	__table_end ( struct setting, settings );
+
 /** Registered setting types */
 static struct setting_type setting_types[0]
 	__table_start ( struct setting_type, setting_types );
 static struct setting_type setting_types_end[0]
 	__table_end ( struct setting_type, setting_types );
 
-/** Registered named settings */
-static struct named_setting named_settings[0]
-	__table_start ( struct named_setting, named_settings );
-static struct named_setting named_settings_end[0]
-	__table_end ( struct named_setting, named_settings );
-
 /** Registered settings applicators */
 static struct settings_applicator settings_applicators[0]
 	__table_start ( struct settings_applicator, settings_applicators );
 static struct settings_applicator settings_applicators_end[0]
 	__table_end ( struct settings_applicator, settings_applicators );
 
-/**
- * Obtain printable version of a settings tag number
- *
- * @v tag		Settings tag number
- * @ret name		String representation of the tag
- */
-static inline char * setting_tag_name ( unsigned int tag ) {
-	static char name[8];
-
-	if ( DHCP_IS_ENCAP_OPT ( tag ) ) {
-		snprintf ( name, sizeof ( name ), "%d.%d",
-			   DHCP_ENCAPSULATOR ( tag ),
-			   DHCP_ENCAPSULATED ( tag ) );
-	} else {
-		snprintf ( name, sizeof ( name ), "%d", tag );
-	}
-	return name;
-}
-
 /******************************************************************************
  *
  * Registered settings blocks
@@ -83,32 +64,33 @@ static inline char * setting_tag_name ( unsigned int tag ) {
  * Store value of simple setting
  *
  * @v options		DHCP option block
- * @v tag		Setting tag number
+ * @v setting		Setting to store
  * @v data		Setting data, or NULL to clear setting
  * @v len		Length of setting data
  * @ret rc		Return status code
  */
-int simple_settings_store ( struct settings *settings, unsigned int tag,
+int simple_settings_store ( struct settings *settings, struct setting *setting,
 			    const void *data, size_t len ) {
 	struct simple_settings *simple =
 		container_of ( settings, struct simple_settings, settings );
-	return dhcpopt_extensible_store ( &simple->dhcpopts, tag, data, len );
+	return dhcpopt_extensible_store ( &simple->dhcpopts, setting->tag,
+					  data, len );
 }
 
 /**
  * Fetch value of simple setting
  *
  * @v options		DHCP option block
- * @v tag		Setting tag number
+ * @v setting		Setting to fetch
  * @v data		Buffer to fill with setting data
  * @v len		Length of buffer
  * @ret len		Length of setting data, or negative error
  */
-int simple_settings_fetch ( struct settings *settings, unsigned int tag,
+int simple_settings_fetch ( struct settings *settings, struct setting *setting,
 			    void *data, size_t len ) {
 	struct simple_settings *simple =
 		container_of ( settings, struct simple_settings, settings );
-	return dhcpopt_fetch ( &simple->dhcpopts, tag, data, len );
+	return dhcpopt_fetch ( &simple->dhcpopts, setting->tag, data, len );
 }
 
 /** Simple settings operations */
@@ -174,14 +156,14 @@ static void reprioritise_settings ( struct settings *settings ) {
 		return;
 
 	/* Read priority, if present */
-	priority = fetch_intz_setting ( settings, DHCP_EB_PRIORITY );
+	priority = fetch_intz_setting ( settings, &priority_setting );
 
 	/* Remove from siblings list */
 	list_del ( &settings->siblings );
 
 	/* Reinsert after any existing blocks which have a higher priority */
 	list_for_each_entry ( tmp, &parent->children, siblings ) {
-		tmp_priority = fetch_intz_setting ( tmp, DHCP_EB_PRIORITY );
+		tmp_priority = fetch_intz_setting ( tmp, &priority_setting );
 		if ( priority > tmp_priority )
 			break;
 	}
@@ -292,12 +274,12 @@ struct settings * find_settings ( const char *name ) {
  * Store value of setting
  *
  * @v settings		Settings block
- * @v tag		Setting tag number
+ * @v setting		Setting to store
  * @v data		Setting data, or NULL to clear setting
  * @v len		Length of setting data
  * @ret rc		Return status code
  */
-int store_setting ( struct settings *settings, unsigned int tag,
+int store_setting ( struct settings *settings, struct setting *setting,
 		    const void *data, size_t len ) {
 	int rc;
 
@@ -306,11 +288,12 @@ int store_setting ( struct settings *settings, unsigned int tag,
 		return -ENODEV;
 
 	/* Store setting */
-	if ( ( rc = settings->op->store ( settings, tag, data, len ) ) != 0 )
+	if ( ( rc = settings->op->store ( settings, setting,
+					  data, len ) ) != 0 )
 		return rc;
 
 	/* Reprioritise settings if necessary */
-	if ( tag == DHCP_EB_PRIORITY )
+	if ( setting_cmp ( setting, &priority_setting ) == 0 )
 		reprioritise_settings ( settings );
 
 	/* If these settings are registered, apply potentially-updated
@@ -331,7 +314,7 @@ int store_setting ( struct settings *settings, unsigned int tag,
  * Fetch value of setting
  *
  * @v settings		Settings block, or NULL to search all blocks
- * @v tag		Setting tag number
+ * @v setting		Setting to fetch
  * @v data		Buffer to fill with setting data
  * @v len		Length of buffer
  * @ret len		Length of setting data, or negative error
@@ -339,7 +322,7 @@ int store_setting ( struct settings *settings, unsigned int tag,
  * The actual length of the setting will be returned even if
  * the buffer was too small.
  */
-int fetch_setting ( struct settings *settings, unsigned int tag,
+int fetch_setting ( struct settings *settings, struct setting *setting,
 		    void *data, size_t len ) {
 	struct settings *child;
 	int ret;
@@ -349,12 +332,14 @@ int fetch_setting ( struct settings *settings, unsigned int tag,
 		settings = &settings_root;
 
 	/* Try this block first */
-	if ( ( ret = settings->op->fetch ( settings, tag, data, len ) ) >= 0)
+	if ( ( ret = settings->op->fetch ( settings, setting,
+					   data, len ) ) >= 0 )
 		return ret;
 
 	/* Recurse into each child block in turn */
 	list_for_each_entry ( child, &settings->children, siblings ) {
-		if ( ( ret = fetch_setting ( child, tag, data, len ) ) >= 0)
+		if ( ( ret = fetch_setting ( child, setting,
+					     data, len ) ) >= 0 )
 			return ret;
 	}
 
@@ -365,21 +350,21 @@ int fetch_setting ( struct settings *settings, unsigned int tag,
  * Fetch length of setting
  *
  * @v settings		Settings block, or NULL to search all blocks
- * @v tag		Setting tag number
+ * @v setting		Setting to fetch
  * @ret len		Length of setting data, or negative error
  *
  * This function can also be used as an existence check for the
  * setting.
  */
-int fetch_setting_len ( struct settings *settings, unsigned int tag ) {
-	return fetch_setting ( settings, tag, NULL, 0 );
+int fetch_setting_len ( struct settings *settings, struct setting *setting ) {
+	return fetch_setting ( settings, setting, NULL, 0 );
 }
 
 /**
  * Fetch value of string setting
  *
  * @v settings		Settings block, or NULL to search all blocks
- * @v tag		Setting tag number
+ * @v setting		Setting to fetch
  * @v data		Buffer to fill with setting string data
  * @v len		Length of buffer
  * @ret len		Length of string setting, or negative error
@@ -388,25 +373,25 @@ int fetch_setting_len ( struct settings *settings, unsigned int tag ) {
  * The returned length will be the length of the underlying setting
  * data.
  */
-int fetch_string_setting ( struct settings *settings, unsigned int tag,
+int fetch_string_setting ( struct settings *settings, struct setting *setting,
 			   char *data, size_t len ) {
 	memset ( data, 0, len );
-	return fetch_setting ( settings, tag, data, ( len - 1 ) );
+	return fetch_setting ( settings, setting, data, ( len - 1 ) );
 }
 
 /**
  * Fetch value of IPv4 address setting
  *
  * @v settings		Settings block, or NULL to search all blocks
- * @v tag		Setting tag number
+ * @v setting		Setting to fetch
  * @v inp		IPv4 address to fill in
  * @ret len		Length of setting, or negative error
  */
-int fetch_ipv4_setting ( struct settings *settings, unsigned int tag,
+int fetch_ipv4_setting ( struct settings *settings, struct setting *setting,
 			 struct in_addr *inp ) {
 	int len;
 
-	len = fetch_setting ( settings, tag, inp, sizeof ( *inp ) );
+	len = fetch_setting ( settings, setting, inp, sizeof ( *inp ) );
 	if ( len < 0 )
 		return len;
 	if ( len < ( int ) sizeof ( *inp ) )
@@ -418,11 +403,11 @@ int fetch_ipv4_setting ( struct settings *settings, unsigned int tag,
  * Fetch value of signed integer setting
  *
  * @v settings		Settings block, or NULL to search all blocks
- * @v tag		Setting tag number
+ * @v setting		Setting to fetch
  * @v value		Integer value to fill in
  * @ret len		Length of setting, or negative error
  */
-int fetch_int_setting ( struct settings *settings, unsigned int tag,
+int fetch_int_setting ( struct settings *settings, struct setting *setting,
 			long *value ) {
 	union {
 		long value;
@@ -433,7 +418,7 @@ int fetch_int_setting ( struct settings *settings, unsigned int tag,
 	int i;
 
 	buf.value = 0;
-	len = fetch_setting ( settings, tag, &buf, sizeof ( buf ) );
+	len = fetch_setting ( settings, setting, &buf, sizeof ( buf ) );
 	if ( len < 0 )
 		return len;
 	if ( len > ( int ) sizeof ( buf ) )
@@ -451,16 +436,16 @@ int fetch_int_setting ( struct settings *settings, unsigned int tag,
  * Fetch value of unsigned integer setting
  *
  * @v settings		Settings block, or NULL to search all blocks
- * @v tag		Setting tag number
+ * @v setting		Setting to fetch
  * @v value		Integer value to fill in
  * @ret len		Length of setting, or negative error
  */
-int fetch_uint_setting ( struct settings *settings, unsigned int tag,
+int fetch_uint_setting ( struct settings *settings, struct setting *setting,
 			 unsigned long *value ) {
 	long svalue;
 	int len;
 
-	len = fetch_int_setting ( settings, tag, &svalue );
+	len = fetch_int_setting ( settings, setting, &svalue );
 	if ( len < 0 )
 		return len;
 
@@ -473,13 +458,13 @@ int fetch_uint_setting ( struct settings *settings, unsigned int tag,
  * Fetch value of signed integer setting, or zero
  *
  * @v settings		Settings block, or NULL to search all blocks
- * @v tag		Setting tag number
+ * @v setting		Setting to fetch
  * @ret value		Setting value, or zero
  */
-long fetch_intz_setting ( struct settings *settings, unsigned int tag ) {
+long fetch_intz_setting ( struct settings *settings, struct setting *setting ){
 	long value = 0;
 
-	fetch_int_setting ( settings, tag, &value );
+	fetch_int_setting ( settings, setting, &value );
 	return value;
 }
 
@@ -487,80 +472,38 @@ long fetch_intz_setting ( struct settings *settings, unsigned int tag ) {
  * Fetch value of unsigned integer setting, or zero
  *
  * @v settings		Settings block, or NULL to search all blocks
- * @v tag		Setting tag number
+ * @v setting		Setting to fetch
  * @ret value		Setting value, or zero
  */
 unsigned long fetch_uintz_setting ( struct settings *settings,
-				    unsigned int tag ) {
+				    struct setting *setting ) {
 	unsigned long value = 0;
 
-	fetch_uint_setting ( settings, tag, &value );
+	fetch_uint_setting ( settings, setting, &value );
 	return value;
 }
 
 /**
- * Copy settings
+ * Compare two settings
  *
- * @v dest		Destination settings block
- * @v source		Source settings block
- * @v encapsulator	Encapsulating setting tag number, or zero
- * @ret rc		Return status code
+ * @v a			Setting to compare
+ * @v b			Setting to compare
+ * @ret 0		Settings are the same
+ * @ret non-zero	Settings are not the same
  */
-static int copy_encap_settings ( struct settings *dest,
-				 struct settings *source,
-				 unsigned int encapsulator ) {
-	unsigned int subtag;
-	unsigned int tag;
-	int len;
-	int check_len;
-	int rc;
+int setting_cmp ( struct setting *a, struct setting *b ) {
 
-	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 */
-			len = fetch_setting_len ( source, tag );
-			if ( len < 0 )
-				break;
-			{
-				char buf[len];
-
-				check_len = fetch_setting ( source, tag, buf,
-							    sizeof ( buf ) );
-				assert ( check_len == len );
-				if ( ( rc = store_setting ( dest, tag, buf,
-							    sizeof(buf) )) !=0)
-					return rc;
-			}
-			break;
-		}
-	}
+	/* If the settings have tags, compare them */
+	if ( a->tag && ( a->tag == b->tag ) )
+		return 0;
 
-	return 0;
-}
-
-/**
- * Copy settings
- *
- * @v dest		Destination settings block
- * @v source		Source settings block
- * @ret rc		Return status code
- */
-int copy_settings ( struct settings *dest, struct settings *source ) {
-	return copy_encap_settings ( dest, source, 0 );
+	/* Otherwise, compare the names */
+	return strcmp ( a->name, b->name );
 }
 
 /******************************************************************************
  *
- * Named and typed setting routines
+ * Formatted setting routines
  *
  ******************************************************************************
  */
@@ -569,23 +512,22 @@ int copy_settings ( struct settings *dest, struct settings *source ) {
  * Store value of typed setting
  *
  * @v settings		Settings block
- * @v tag		Setting tag number
+ * @v setting		Setting to store
  * @v type		Settings type
  * @v value		Formatted setting data, or NULL
  * @ret rc		Return status code
  */
-int store_typed_setting ( struct settings *settings,
-			  unsigned int tag, struct setting_type *type,
-			  const char *value ) {
+int storef_setting ( struct settings *settings, struct setting *setting,
+		     const char *value ) {
 
 	/* NULL value implies deletion.  Avoid imposing the burden of
 	 * checking for NULL values on each typed setting's storef()
 	 * method.
 	 */
 	if ( ! value )
-		return delete_setting ( settings, tag );
+		return delete_setting ( settings, setting );
 		
-	return type->storef ( settings, tag, value );
+	return setting->type->storef ( settings, setting, value );
 }
 
 /**
@@ -594,11 +536,10 @@ int store_typed_setting ( struct settings *settings,
  * @v name		Name
  * @ret setting		Named setting, or NULL
  */
-static struct named_setting * find_named_setting ( const char *name ) {
-	struct named_setting *setting;
+static struct setting * find_setting ( const char *name ) {
+	struct setting *setting;
 
-	for ( setting = named_settings ; setting < named_settings_end ;
-	      setting++ ) {
+	for ( setting = settings ; setting < settings_end ; setting++ ) {
 		if ( strcmp ( name, setting->name ) == 0 )
 			return setting;
 	}
@@ -625,9 +566,8 @@ static struct setting_type * find_setting_type ( const char *name ) {
  * Parse setting name
  *
  * @v name		Name of setting
- * @ret settings	Settings block, or NULL
- * @ret tag		Setting tag number
- * @ret type		Setting type
+ * @v settings		Settings block to fill in
+ * @v setting		Setting to fill in
  * @ret rc		Return status code
  *
  * Interprets a name of the form
@@ -635,30 +575,29 @@ static struct setting_type * find_setting_type ( const char *name ) {
  * fields.
  */
 static int parse_setting_name ( const char *name, struct settings **settings,
-				unsigned int *tag,
-				struct setting_type **type ) {
+				struct setting *setting ) {
 	char tmp_name[ strlen ( name ) + 1 ];
 	char *settings_name;
-	char *tag_name;
+	char *setting_name;
 	char *type_name;
-	struct named_setting *named_setting;
+	struct setting *named_setting;
 	char *tmp;
 
 	/* Set defaults */
 	*settings = &settings_root;
-	*tag = 0;
-	*type = &setting_type_hex;
+	memset ( setting, 0, sizeof ( *setting ) );
+	setting->type = &setting_type_hex;
 
-	/* Split name into "[settings_name/]tag_name[:type_name]" */
+	/* Split name into "[settings_name/]setting_name[:type_name]" */
 	memcpy ( tmp_name, name, sizeof ( tmp_name ) );
-	if ( ( tag_name = strchr ( tmp_name, '/' ) ) != NULL ) {
-		*(tag_name++) = 0;
+	if ( ( setting_name = strchr ( tmp_name, '/' ) ) != NULL ) {
+		*(setting_name++) = 0;
 		settings_name = tmp_name;
 	} else {
-		tag_name = tmp_name;
+		setting_name = tmp_name;
 		settings_name = NULL;
 	}
-	if ( ( type_name = strchr ( tag_name, ':' ) ) != NULL )
+	if ( ( type_name = strchr ( setting_name, ':' ) ) != NULL )
 		*(type_name++) = 0;
 
 	/* Identify settings block, if specified */
@@ -672,19 +611,19 @@ static int parse_setting_name ( const char *name, struct settings **settings,
 	}
 
 	/* Identify tag number */
-	if ( ( named_setting = find_named_setting ( tag_name ) ) != NULL ) {
-		*tag = named_setting->tag;
-		*type = named_setting->type;
+	if ( ( named_setting = find_setting ( setting_name ) ) != NULL ) {
+		memcpy ( setting, named_setting, sizeof ( *setting ) );
 	} else {
 		/* Unrecognised name: try to interpret as a tag number */
-		tmp = tag_name;
+		tmp = setting_name;
 		while ( 1 ) {
-			*tag = ( ( *tag << 8 ) | strtoul ( tmp, &tmp, 0 ) );
+			setting->tag = ( ( setting->tag << 8 ) |
+					 strtoul ( tmp, &tmp, 0 ) );
 			if ( *tmp == 0 )
 				break;
 			if ( *tmp != '.' ) {
-				DBG ( "Invalid tag number \"%s\" in \"%s\"\n",
-				      tag_name, name );
+				DBG ( "Invalid setting \"%s\" in \"%s\"\n",
+				      setting_name, name );
 				return -ENOENT;
 			}
 			tmp++;
@@ -693,8 +632,8 @@ static int parse_setting_name ( const char *name, struct settings **settings,
 
 	/* Identify setting type, if specified */
 	if ( type_name ) {
-		*type = find_setting_type ( type_name );
-		if ( *type == NULL ) {
+		setting->type = find_setting_type ( type_name );
+		if ( setting->type == NULL ) {
 			DBG ( "Invalid setting type \"%s\" in \"%s\"\n",
 			      type_name, name );
 			return -ENOTSUP;
@@ -711,16 +650,14 @@ static int parse_setting_name ( const char *name, struct settings **settings,
  * @v value		Formatted setting data, or NULL
  * @ret rc		Return status code
  */
-int store_named_setting ( const char *name, const char *value ) {
+int storef_named_setting ( const char *name, const char *value ) {
 	struct settings *settings;
-	unsigned int tag;
-	struct setting_type *type;
+	struct setting setting;
 	int rc;
 
-	if ( ( rc = parse_setting_name ( name, &settings, &tag,
-					 &type ) ) != 0 )
+	if ( ( rc = parse_setting_name ( name, &settings, &setting ) ) != 0 )
 		return rc;
-	return store_typed_setting ( settings, tag, type, value );
+	return storef_setting ( settings, &setting, value );
 }
 
 /**
@@ -731,16 +668,14 @@ int store_named_setting ( const char *name, const char *value ) {
  * @v len		Length of buffer
  * @ret len		Length of formatted value, or negative error
  */
-int fetch_named_setting ( const char *name, char *buf, size_t len ) {
+int fetchf_named_setting ( const char *name, char *buf, size_t len ) {
 	struct settings *settings;
-	unsigned int tag;
-	struct setting_type *type;
+	struct setting setting;
 	int rc;
 
-	if ( ( rc = parse_setting_name ( name, &settings, &tag,
-					 &type ) ) != 0 )
+	if ( ( rc = parse_setting_name ( name, &settings, &setting ) ) != 0 )
 		return rc;
-	return fetch_typed_setting ( settings, tag, type, buf, len );
+	return fetchf_setting ( settings, &setting, buf, len );
 }
 
 /******************************************************************************
@@ -754,27 +689,27 @@ int fetch_named_setting ( const char *name, char *buf, size_t len ) {
  * Parse and store value of string setting
  *
  * @v settings		Settings block
- * @v tag		Setting tag number
+ * @v setting		Setting to store
  * @v value		Formatted setting data
  * @ret rc		Return status code
  */
-static int storef_string ( struct settings *settings, unsigned int tag,
+static int storef_string ( struct settings *settings, struct setting *setting,
 			   const char *value ) {
-	return store_setting ( settings, tag, value, strlen ( value ) );
+	return store_setting ( settings, setting, value, strlen ( value ) );
 }
 
 /**
  * Fetch and format value of string setting
  *
  * @v settings		Settings block, or NULL to search all blocks
- * @v tag		Setting tag number
+ * @v setting		Setting to fetch
  * @v buf		Buffer to contain formatted value
  * @v len		Length of buffer
  * @ret len		Length of formatted value, or negative error
  */
-static int fetchf_string ( struct settings *settings, unsigned int tag,
+static int fetchf_string ( struct settings *settings, struct setting *setting,
 			   char *buf, size_t len ) {
-	return fetch_string_setting ( settings, tag, buf, len );
+	return fetch_string_setting ( settings, setting, buf, len );
 }
 
 /** A string setting type */
@@ -788,34 +723,34 @@ struct setting_type setting_type_string __setting_type = {
  * Parse and store value of IPv4 address setting
  *
  * @v settings		Settings block
- * @v tag		Setting tag number
+ * @v setting		Setting to store
  * @v value		Formatted setting data
  * @ret rc		Return status code
  */
-static int storef_ipv4 ( struct settings *settings, unsigned int tag,
+static int storef_ipv4 ( struct settings *settings, struct setting *setting,
 			 const char *value ) {
 	struct in_addr ipv4;
 
 	if ( inet_aton ( value, &ipv4 ) == 0 )
 		return -EINVAL;
-	return store_setting ( settings, tag, &ipv4, sizeof ( ipv4 ) );
+	return store_setting ( settings, setting, &ipv4, sizeof ( ipv4 ) );
 }
 
 /**
  * Fetch and format value of IPv4 address setting
  *
  * @v settings		Settings block, or NULL to search all blocks
- * @v tag		Setting tag number
+ * @v setting		Setting to fetch
  * @v buf		Buffer to contain formatted value
  * @v len		Length of buffer
  * @ret len		Length of formatted value, or negative error
  */
-static int fetchf_ipv4 ( struct settings *settings, unsigned int tag,
+static int fetchf_ipv4 ( struct settings *settings, struct setting *setting,
 			 char *buf, size_t len ) {
 	struct in_addr ipv4;
 	int rc;
 
-	if ( ( rc = fetch_ipv4_setting ( settings, tag, &ipv4 ) ) < 0 )
+	if ( ( rc = fetch_ipv4_setting ( settings, setting, &ipv4 ) ) < 0 )
 		return rc;
 	return snprintf ( buf, len, inet_ntoa ( ipv4 ) );
 }
@@ -831,12 +766,12 @@ struct setting_type setting_type_ipv4 __setting_type = {
  * Parse and store value of integer setting
  *
  * @v settings		Settings block
- * @v tag		Setting tag number
+ * @v setting		Setting to store
  * @v value		Formatted setting data
  * @v size		Integer size, in bytes
  * @ret rc		Return status code
  */
-static int storef_int ( struct settings *settings, unsigned int tag,
+static int storef_int ( struct settings *settings, struct setting *setting,
 			const char *value, unsigned int size ) {
 	union {
 		uint32_t num;
@@ -847,7 +782,7 @@ static int storef_int ( struct settings *settings, unsigned int tag,
 	u.num = htonl ( strtoul ( value, &endp, 0 ) );
 	if ( *endp )
 		return -EINVAL;
-	return store_setting ( settings, tag, 
+	return store_setting ( settings, setting, 
 			       &u.bytes[ sizeof ( u ) - size ], size );
 }
 
@@ -855,59 +790,59 @@ static int storef_int ( struct settings *settings, unsigned int tag,
  * Parse and store value of 8-bit integer setting
  *
  * @v settings		Settings block
- * @v tag		Setting tag number
+ * @v setting		Setting to store
  * @v value		Formatted setting data
  * @v size		Integer size, in bytes
  * @ret rc		Return status code
  */
-static int storef_int8 ( struct settings *settings, unsigned int tag,
+static int storef_int8 ( struct settings *settings, struct setting *setting,
 			 const char *value ) {
-	return storef_int ( settings, tag, value, 1 );
+	return storef_int ( settings, setting, value, 1 );
 }
 
 /**
  * Parse and store value of 16-bit integer setting
  *
  * @v settings		Settings block
- * @v tag		Setting tag number
+ * @v setting		Setting to store
  * @v value		Formatted setting data
  * @v size		Integer size, in bytes
  * @ret rc		Return status code
  */
-static int storef_int16 ( struct settings *settings, unsigned int tag,
+static int storef_int16 ( struct settings *settings, struct setting *setting,
 			  const char *value ) {
-	return storef_int ( settings, tag, value, 2 );
+	return storef_int ( settings, setting, value, 2 );
 }
 
 /**
  * Parse and store value of 32-bit integer setting
  *
  * @v settings		Settings block
- * @v tag		Setting tag number
+ * @v setting		Setting to store
  * @v value		Formatted setting data
  * @v size		Integer size, in bytes
  * @ret rc		Return status code
  */
-static int storef_int32 ( struct settings *settings, unsigned int tag,
+static int storef_int32 ( struct settings *settings, struct setting *setting,
 			  const char *value ) {
-	return storef_int ( settings, tag, value, 4 );
+	return storef_int ( settings, setting, value, 4 );
 }
 
 /**
  * Fetch and format value of signed integer setting
  *
  * @v settings		Settings block, or NULL to search all blocks
- * @v tag		Setting tag number
+ * @v setting		Setting to fetch
  * @v buf		Buffer to contain formatted value
  * @v len		Length of buffer
  * @ret len		Length of formatted value, or negative error
  */
-static int fetchf_int ( struct settings *settings, unsigned int tag,
+static int fetchf_int ( struct settings *settings, struct setting *setting,
 			char *buf, size_t len ) {
 	long value;
 	int rc;
 
-	if ( ( rc = fetch_int_setting ( settings, tag, &value ) ) < 0 )
+	if ( ( rc = fetch_int_setting ( settings, setting, &value ) ) < 0 )
 		return rc;
 	return snprintf ( buf, len, "%ld", value );
 }
@@ -916,17 +851,17 @@ static int fetchf_int ( struct settings *settings, unsigned int tag,
  * Fetch and format value of unsigned integer setting
  *
  * @v settings		Settings block, or NULL to search all blocks
- * @v tag		Setting tag number
+ * @v setting		Setting to fetch
  * @v buf		Buffer to contain formatted value
  * @v len		Length of buffer
  * @ret len		Length of formatted value, or negative error
  */
-static int fetchf_uint ( struct settings *settings, unsigned int tag,
+static int fetchf_uint ( struct settings *settings, struct setting *setting,
 			 char *buf, size_t len ) {
 	unsigned long value;
 	int rc;
 
-	if ( ( rc = fetch_uint_setting ( settings, tag, &value ) ) < 0 )
+	if ( ( rc = fetch_uint_setting ( settings, setting, &value ) ) < 0 )
 		return rc;
 	return snprintf ( buf, len, "%#lx", value );
 }
@@ -977,11 +912,11 @@ struct setting_type setting_type_uint32 __setting_type = {
  * Parse and store value of hex string setting
  *
  * @v settings		Settings block
- * @v tag		Setting tag number
+ * @v setting		Setting to store
  * @v value		Formatted setting data
  * @ret rc		Return status code
  */
-static int storef_hex ( struct settings *settings, unsigned int tag,
+static int storef_hex ( struct settings *settings, struct setting *setting,
 			const char *value ) {
 	char *ptr = ( char * ) value;
 	uint8_t bytes[ strlen ( value ) ]; /* cannot exceed strlen(value) */
@@ -991,7 +926,7 @@ static int storef_hex ( struct settings *settings, unsigned int tag,
 		bytes[len++] = strtoul ( ptr, &ptr, 16 );
 		switch ( *ptr ) {
 		case '\0' :
-			return store_setting ( settings, tag, bytes, len );
+			return store_setting ( settings, setting, bytes, len );
 		case ':' :
 			ptr++;
 			break;
@@ -1005,26 +940,27 @@ static int storef_hex ( struct settings *settings, unsigned int tag,
  * Fetch and format value of hex string setting
  *
  * @v settings		Settings block, or NULL to search all blocks
- * @v tag		Setting tag number
+ * @v setting		Setting to fetch
  * @v buf		Buffer to contain formatted value
  * @v len		Length of buffer
  * @ret len		Length of formatted value, or negative error
  */
-static int fetchf_hex ( struct settings *settings, unsigned int tag,
+static int fetchf_hex ( struct settings *settings, struct setting *setting,
 			char *buf, size_t len ) {
 	int raw_len;
 	int check_len;
 	int used = 0;
 	int i;
 
-	raw_len = fetch_setting_len ( settings, tag );
+	raw_len = fetch_setting_len ( settings, setting );
 	if ( raw_len < 0 )
 		return raw_len;
 
 	{
 		uint8_t raw[raw_len];
 
-		check_len = fetch_setting ( settings, tag, raw, sizeof (raw) );
+		check_len = fetch_setting ( settings, setting, raw,
+					    sizeof ( raw ) );
 		assert ( check_len == raw_len );
 		
 		if ( len )
@@ -1047,83 +983,55 @@ struct setting_type setting_type_hex __setting_type = {
 
 /******************************************************************************
  *
- * Named settings
+ * Settings
  *
  ******************************************************************************
  */
 
-/** Some basic setting definitions */
-struct named_setting basic_named_settings[] __named_setting = {
-	{
-		.name = "ip",
-		.description = "IPv4 address",
-		.tag = DHCP_EB_YIADDR,
-		.type = &setting_type_ipv4,
-	},
-	{
-		.name = "netmask",
-		.description = "IPv4 subnet mask",
-		.tag = DHCP_SUBNET_MASK,
-		.type = &setting_type_ipv4,
-	},
-	{
-		.name = "gateway",
-		.description = "Default gateway",
-		.tag = DHCP_ROUTERS,
-		.type = &setting_type_ipv4,
-	},
-	{
-		.name = "dns",
-		.description = "DNS server",
-		.tag = DHCP_DNS_SERVERS,
-		.type = &setting_type_ipv4,
-	},
-	{
-		.name = "hostname",
-		.description = "Host name",
-		.tag = DHCP_HOST_NAME,
-		.type = &setting_type_string,
-	},
-	{
-		.name = "next-server",
-		.description = "TFTP server",
-		.tag = DHCP_EB_SIADDR,
-		.type = &setting_type_ipv4,
-	},
-	{
-		.name = "filename",
-		.description = "Boot filename",
-		.tag = DHCP_BOOTFILE_NAME,
-		.type = &setting_type_string,
-	},
-	{
-		.name = "root-path",
-		.description = "NFS/iSCSI root path",
-		.tag = DHCP_ROOT_PATH,
-		.type = &setting_type_string,
-	},
-	{
-		.name = "username",
-		.description = "User name",
-		.tag = DHCP_EB_USERNAME,
-		.type = &setting_type_string,
-	},
-	{
-		.name = "password",
-		.description = "Password",
-		.tag = DHCP_EB_PASSWORD,
-		.type = &setting_type_string,
-	},
-	{
-		.name = "initiator-iqn",
-		.description = "iSCSI initiator name",
-		.tag = DHCP_ISCSI_INITIATOR_IQN,
-		.type = &setting_type_string,
-	},
-	{
-		.name = "priority",
-		.description = "Priority of these settings",
-		.tag = DHCP_EB_PRIORITY,
-		.type = &setting_type_int8,
-	},
+/** Hostname setting */
+struct setting hostname_setting __setting = {
+	.name = "hostname",
+	.description = "Host name",
+	.tag = DHCP_HOST_NAME,
+	.type = &setting_type_string,
+};
+
+/** Filename setting */
+struct setting filename_setting __setting = {
+	.name = "filename",
+	.description = "Boot filename",
+	.tag = DHCP_BOOTFILE_NAME,
+	.type = &setting_type_string,
+};
+
+/** Root path setting */
+struct setting root_path_setting __setting = {
+	.name = "root-path",
+	.description = "NFS/iSCSI root path",
+	.tag = DHCP_ROOT_PATH,
+	.type = &setting_type_string,
+};
+
+/** Username setting */
+struct setting username_setting __setting = {
+	.name = "username",
+	.description = "User name",
+	.tag = DHCP_EB_USERNAME,
+	.type = &setting_type_string,
+};
+
+/** Password setting */
+struct setting password_setting __setting = {
+	.name = "password",
+	.description = "Password",
+	.tag = DHCP_EB_PASSWORD,
+	.type = &setting_type_string,
+};
+
+/** Priority setting */
+struct setting priority_setting __setting = {
+	.name = "priority",
+	.description = "Priority of these settings",
+	.tag = DHCP_EB_PRIORITY,
+	.type = &setting_type_int8,
 };