src/usr/pxemenu.c - ipxe - Git at Google

 /*
  * Copyright (C) 2009 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 <stdio.h>
 #include <string.h>
 #include <errno.h>
 #include <ctype.h>
 #include <byteswap.h>
 #include <curses.h>
 #include <ipxe/console.h>
 #include <ipxe/dhcp.h>
 #include <ipxe/keys.h>
 #include <ipxe/timer.h>
 #include <ipxe/uri.h>
 #include <ipxe/ansicol.h>
 #include <usr/dhcpmgmt.h>
 #include <usr/autoboot.h>

 /** @file
  *
  * PXE Boot Menus
  *
  */

 /** A PXE boot menu item */
 struct pxe_menu_item {
 	/** Boot Server type */
 	unsigned int type;
 	/** Description */
 	char *desc;
 };

 /**
  * A PXE boot menu
  *
  * This structure encapsulates the menu information provided via DHCP
  * options.
  */
 struct pxe_menu {
 	/** Prompt string (optional) */
 	const char *prompt;
 	/** Timeout (in seconds)
 	 *
 	 * Negative indicates no timeout (i.e. wait indefinitely)
 	 */
 	int timeout;
 	/** Number of menu items */
 	unsigned int num_items;
 	/** Selected menu item */
 	unsigned int selection;
 	/** Menu items */
 	struct pxe_menu_item items[0];
 };

 /**
  * Parse and allocate PXE boot menu
  *
  * @v menu		PXE boot menu to fill in
  * @ret rc		Return status code
  *
  * It is the callers responsibility to eventually free the allocated
  * boot menu.
  */
 static int pxe_menu_parse ( struct pxe_menu **menu ) {
 	struct setting pxe_boot_menu_prompt_setting =
 		{ .tag = DHCP_PXE_BOOT_MENU_PROMPT };
 	struct setting pxe_boot_menu_setting =
 		{ .tag = DHCP_PXE_BOOT_MENU };
 	uint8_t raw_menu[256];
 	int raw_prompt_len;
 	int raw_menu_len;
 	struct dhcp_pxe_boot_menu *raw_menu_item;
 	struct dhcp_pxe_boot_menu_prompt *raw_menu_prompt;
 	void *raw_menu_end;
 	unsigned int num_menu_items;
 	unsigned int i;
 	int rc;

 	/* Fetch raw menu */
 	memset ( raw_menu, 0, sizeof ( raw_menu ) );
 	if ( ( raw_menu_len = fetch_raw_setting ( NULL, &pxe_boot_menu_setting,
 						  raw_menu,
 						  sizeof ( raw_menu ) ) ) < 0 ){
 		rc = raw_menu_len;
 		DBG ( "Could not retrieve raw PXE boot menu: %s\n",
 		      strerror ( rc ) );
 		return rc;
 	}
 	if ( raw_menu_len >= ( int ) sizeof ( raw_menu ) ) {
 		DBG ( "Raw PXE boot menu too large for buffer\n" );
 		return -ENOSPC;
 	}
 	raw_menu_end = ( raw_menu + raw_menu_len );

 	/* Fetch raw prompt length */
 	raw_prompt_len =
 		fetch_raw_setting ( NULL, &pxe_boot_menu_prompt_setting,
 				    NULL, 0 );
 	if ( raw_prompt_len < 0 )
 		raw_prompt_len = 0;

 	/* Count menu items */
 	num_menu_items = 0;
 	raw_menu_item = ( ( void * ) raw_menu );
 	while ( 1 ) {
 		if ( ( ( ( void * ) raw_menu_item ) +
 		       sizeof ( *raw_menu_item ) ) > raw_menu_end )
 			break;
 		if ( ( ( ( void * ) raw_menu_item ) +
 		       sizeof ( *raw_menu_item ) +
 		       raw_menu_item->desc_len ) > raw_menu_end )
 			break;
 		num_menu_items++;
 		raw_menu_item = ( ( ( void * ) raw_menu_item ) +
 				  sizeof ( *raw_menu_item ) +
 				  raw_menu_item->desc_len );
 	}

 	/* Allocate space for parsed menu */
 	*menu = zalloc ( sizeof ( **menu ) +
 			 ( num_menu_items * sizeof ( (*menu)->items[0] ) ) +
 			 raw_menu_len + 1 /* NUL */ +
 			 raw_prompt_len + 1 /* NUL */ );
 	if ( ! *menu ) {
 		DBG ( "Could not allocate PXE boot menu\n" );
 		return -ENOMEM;
 	}

 	/* Fill in parsed menu */
 	(*menu)->num_items = num_menu_items;
 	raw_menu_item = ( ( ( void * ) (*menu) ) + sizeof ( **menu ) +
 			  ( num_menu_items * sizeof ( (*menu)->items[0] ) ) );
 	memcpy ( raw_menu_item, raw_menu, raw_menu_len );
 	for ( i = 0 ; i < num_menu_items ; i++ ) {
 		(*menu)->items[i].type = le16_to_cpu ( raw_menu_item->type );
 		(*menu)->items[i].desc = raw_menu_item->desc;
 		/* Set type to 0; this ensures that the description
 		 * for the previous menu item is NUL-terminated.
 		 * (Final item is NUL-terminated anyway.)
 		 */
 		raw_menu_item->type = 0;
 		raw_menu_item = ( ( ( void * ) raw_menu_item ) +
 				  sizeof ( *raw_menu_item ) +
 				  raw_menu_item->desc_len );
 	}
 	if ( raw_prompt_len ) {
 		raw_menu_prompt = ( ( ( void * ) raw_menu_item ) +
 				    1 /* NUL */ );
 		fetch_raw_setting ( NULL, &pxe_boot_menu_prompt_setting,
 				    raw_menu_prompt, raw_prompt_len );
 		(*menu)->timeout =
 			( ( raw_menu_prompt->timeout == 0xff ) ?
 			  -1 : raw_menu_prompt->timeout );
 		(*menu)->prompt = raw_menu_prompt->prompt;
 	} else {
 		(*menu)->timeout = -1;
 	}

 	return 0;
 }

 /**
  * Draw PXE boot menu item
  *
  * @v menu		PXE boot menu
  * @v index		Index of item to draw
  * @v selected		Item is selected
  */
 static void pxe_menu_draw_item ( struct pxe_menu *menu,
 				 unsigned int index, int selected ) {
 	char buf[COLS+1];
 	size_t len;
 	unsigned int row;

 	/* Prepare space-padded row content */
 	len = snprintf ( buf, sizeof ( buf ), " %c. %s",
 			 ( 'A' + index ), menu->items[index].desc );
 	while ( len < ( sizeof ( buf ) - 1 ) )
 		buf[len++] = ' ';
 	buf[ sizeof ( buf ) - 1 ] = '\0';

 	/* Draw row */
 	row = ( LINES - menu->num_items + index );
 	color_set ( ( selected ? CPAIR_PXE : CPAIR_DEFAULT ), NULL );
 	mvprintw ( row, 0, "%s", buf );
 	move ( row, 1 );
 }

 /**
  * Make selection from PXE boot menu
  *
  * @v menu		PXE boot menu
  * @ret rc		Return status code
  */
 static int pxe_menu_select ( struct pxe_menu *menu ) {
 	int key;
 	unsigned int key_selection;
 	unsigned int i;
 	int rc = 0;

 	/* Initialise UI */
 	initscr();
 	start_color();
 	color_set ( CPAIR_DEFAULT, NULL );

 	/* Draw initial menu */
 	for ( i = 0 ; i < menu->num_items ; i++ )
 		printf ( "\n" );
 	for ( i = 0 ; i < menu->num_items ; i++ )
 		pxe_menu_draw_item ( menu, ( menu->num_items - i - 1 ), 0 );

 	while ( 1 ) {

 		/* Highlight currently selected item */
 		pxe_menu_draw_item ( menu, menu->selection, 1 );

 		/* Wait for keyboard input */
 		key = getkey ( 0 );

 		/* Unhighlight currently selected item */
 		pxe_menu_draw_item ( menu, menu->selection, 0 );

 		/* Act upon key */
 		if ( ( key == CR ) || ( key == LF ) ) {
 			pxe_menu_draw_item ( menu, menu->selection, 1 );
 			break;
 		} else if ( ( key == CTRL_C ) || ( key == ESC ) ) {
 			rc = -ECANCELED;
 			break;
 		} else if ( key == KEY_UP ) {
 			if ( menu->selection > 0 )
 				menu->selection--;
 		} else if ( key == KEY_DOWN ) {
 			if ( menu->selection < ( menu->num_items - 1 ) )
 				menu->selection++;
 		} else if ( ( key < KEY_MIN ) &&
 			    ( ( key_selection = ( toupper ( key ) - 'A' ) )
 			      < menu->num_items ) ) {
 			menu->selection = key_selection;
 			pxe_menu_draw_item ( menu, menu->selection, 1 );
 			break;
 		}
 	}

 	/* Shut down UI */
 	endwin();

 	return rc;
 }

 /**
  * Prompt for (and make selection from) PXE boot menu
  *
  * @v menu		PXE boot menu
  * @ret rc		Return status code
  */
 static int pxe_menu_prompt_and_select ( struct pxe_menu *menu ) {
 	unsigned long start = currticks();
 	unsigned long now;
 	unsigned long elapsed;
 	size_t len = 0;
 	int key;
 	int rc = 0;

 	/* Display menu immediately, if specified to do so */
 	if ( menu->timeout < 0 ) {
 		if ( menu->prompt )
 			printf ( "%s\n", menu->prompt );
 		return pxe_menu_select ( menu );
 	}

 	/* Display prompt, if specified */
 	if ( menu->prompt )
 		printf ( "%s", menu->prompt );

 	/* Wait for timeout, if specified */
 	while ( menu->timeout > 0 ) {
 		if ( ! len )
 			len = printf ( " (%d)", menu->timeout );
 		if ( iskey() ) {
 			key = getkey ( 0 );
 			if ( key == KEY_F8 ) {
 				/* Display menu */
 				printf ( "\n" );
 				return pxe_menu_select ( menu );
 			} else if ( ( key == CTRL_C ) || ( key == ESC ) ) {
 				/* Abort */
 				rc = -ECANCELED;
 				break;
 			} else {
 				/* Stop waiting */
 				break;
 			}
 		}
 		now = currticks();
 		elapsed = ( now - start );
 		if ( elapsed >= TICKS_PER_SEC ) {
 			menu->timeout -= 1;
 			do {
 				printf ( "\b \b" );
 			} while ( --len );
 			start = now;
 		}
 	}

 	/* Return with default option selected */
 	printf ( "\n" );
 	return rc;
 }

 /**
  * Boot using PXE boot menu
  *
  * @ret rc		Return status code
  *
  * Note that a success return status indicates that a PXE boot menu
  * item has been selected, and that the DHCP session should perform a
  * boot server request/ack.
  */
 int pxe_menu_boot ( struct net_device *netdev ) {
 	struct pxe_menu *menu;
 	unsigned int pxe_type;
 	struct settings *pxebs_settings;
 	struct uri *uri;
 	int rc;

 	/* Parse and allocate boot menu */
 	if ( ( rc = pxe_menu_parse ( &menu ) ) != 0 )
 		return rc;

 	/* Make selection from boot menu */
 	if ( ( rc = pxe_menu_prompt_and_select ( menu ) ) != 0 ) {
 		free ( menu );
 		return rc;
 	}
 	pxe_type = menu->items[menu->selection].type;

 	/* Free boot menu */
 	free ( menu );

 	/* Return immediately if local boot selected */
 	if ( ! pxe_type )
 		return 0;

 	/* Attempt PXE Boot Server Discovery */
 	if ( ( rc = pxebs ( netdev, pxe_type ) ) != 0 )
 		return rc;

 	/* Fetch next server and filename */
 	pxebs_settings = find_settings ( PXEBS_SETTINGS_NAME );
 	assert ( pxebs_settings );
 	uri = fetch_next_server_and_filename ( pxebs_settings );
 	if ( ! uri )
 		return -ENOMEM;

 	/* Attempt boot */
 	rc = uriboot ( uri, NULL, 0, 0, NULL, URIBOOT_NO_SAN );
 	uri_put ( uri );
 	return rc;
 }
	/*
	* Copyright (C) 2009 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 <stdio.h>
	#include <string.h>
	#include <errno.h>
	#include <ctype.h>
	#include <byteswap.h>
	#include <curses.h>
	#include <ipxe/console.h>
	#include <ipxe/dhcp.h>
	#include <ipxe/keys.h>
	#include <ipxe/timer.h>
	#include <ipxe/uri.h>
	#include <ipxe/ansicol.h>
	#include <usr/dhcpmgmt.h>
	#include <usr/autoboot.h>

	/** @file
	*
	* PXE Boot Menus
	*
	*/

	/** A PXE boot menu item */
	struct pxe_menu_item {
	/** Boot Server type */
	unsigned int type;
	/** Description */
	char *desc;
	};

	/**
	* A PXE boot menu
	*
	* This structure encapsulates the menu information provided via DHCP
	* options.
	*/
	struct pxe_menu {
	/** Prompt string (optional) */
	const char *prompt;
	/** Timeout (in seconds)
	*
	* Negative indicates no timeout (i.e. wait indefinitely)
	*/
	int timeout;
	/** Number of menu items */
	unsigned int num_items;
	/** Selected menu item */
	unsigned int selection;
	/** Menu items */
	struct pxe_menu_item items[0];
	};

	/**
	* Parse and allocate PXE boot menu
	*
	* @v menu PXE boot menu to fill in
	* @ret rc Return status code
	*
	* It is the callers responsibility to eventually free the allocated
	* boot menu.
	*/
	static int pxe_menu_parse ( struct pxe_menu **menu ) {
	struct setting pxe_boot_menu_prompt_setting =
	{ .tag = DHCP_PXE_BOOT_MENU_PROMPT };
	struct setting pxe_boot_menu_setting =
	{ .tag = DHCP_PXE_BOOT_MENU };
	uint8_t raw_menu[256];
	int raw_prompt_len;
	int raw_menu_len;
	struct dhcp_pxe_boot_menu *raw_menu_item;
	struct dhcp_pxe_boot_menu_prompt *raw_menu_prompt;
	void *raw_menu_end;
	unsigned int num_menu_items;
	unsigned int i;
	int rc;

	/* Fetch raw menu */
	memset ( raw_menu, 0, sizeof ( raw_menu ) );
	if ( ( raw_menu_len = fetch_raw_setting ( NULL, &pxe_boot_menu_setting,
	raw_menu,
	sizeof ( raw_menu ) ) ) < 0 ){
	rc = raw_menu_len;
	DBG ( "Could not retrieve raw PXE boot menu: %s\n",
	strerror ( rc ) );
	return rc;
	}
	if ( raw_menu_len >= ( int ) sizeof ( raw_menu ) ) {
	DBG ( "Raw PXE boot menu too large for buffer\n" );
	return -ENOSPC;
	}
	raw_menu_end = ( raw_menu + raw_menu_len );

	/* Fetch raw prompt length */
	raw_prompt_len =
	fetch_raw_setting ( NULL, &pxe_boot_menu_prompt_setting,
	NULL, 0 );
	if ( raw_prompt_len < 0 )
	raw_prompt_len = 0;

	/* Count menu items */
	num_menu_items = 0;
	raw_menu_item = ( ( void * ) raw_menu );
	while ( 1 ) {
	if ( ( ( ( void * ) raw_menu_item ) +
	sizeof ( *raw_menu_item ) ) > raw_menu_end )
	break;
	if ( ( ( ( void * ) raw_menu_item ) +
	sizeof ( *raw_menu_item ) +
	raw_menu_item->desc_len ) > raw_menu_end )
	break;
	num_menu_items++;
	raw_menu_item = ( ( ( void * ) raw_menu_item ) +
	sizeof ( *raw_menu_item ) +
	raw_menu_item->desc_len );
	}

	/* Allocate space for parsed menu */
	menu = zalloc ( sizeof ( *menu ) +
	( num_menu_items * sizeof ( (*menu)->items[0] ) ) +
	raw_menu_len + 1 /* NUL */ +
	raw_prompt_len + 1 /* NUL */ );
	if ( ! *menu ) {
	DBG ( "Could not allocate PXE boot menu\n" );
	return -ENOMEM;
	}

	/* Fill in parsed menu */
	(*menu)->num_items = num_menu_items;
	raw_menu_item = ( ( ( void * ) (menu) ) + sizeof ( *menu ) +
	( num_menu_items * sizeof ( (*menu)->items[0] ) ) );
	memcpy ( raw_menu_item, raw_menu, raw_menu_len );
	for ( i = 0 ; i < num_menu_items ; i++ ) {
	(*menu)->items[i].type = le16_to_cpu ( raw_menu_item->type );
	(*menu)->items[i].desc = raw_menu_item->desc;
	/* Set type to 0; this ensures that the description
	* for the previous menu item is NUL-terminated.
	* (Final item is NUL-terminated anyway.)
	*/
	raw_menu_item->type = 0;
	raw_menu_item = ( ( ( void * ) raw_menu_item ) +
	sizeof ( *raw_menu_item ) +
	raw_menu_item->desc_len );
	}
	if ( raw_prompt_len ) {
	raw_menu_prompt = ( ( ( void * ) raw_menu_item ) +
	1 /* NUL */ );
	fetch_raw_setting ( NULL, &pxe_boot_menu_prompt_setting,
	raw_menu_prompt, raw_prompt_len );
	(*menu)->timeout =
	( ( raw_menu_prompt->timeout == 0xff ) ?
	-1 : raw_menu_prompt->timeout );
	(*menu)->prompt = raw_menu_prompt->prompt;
	} else {
	(*menu)->timeout = -1;
	}

	return 0;
	}

	/**
	* Draw PXE boot menu item
	*
	* @v menu PXE boot menu
	* @v index Index of item to draw
	* @v selected Item is selected
	*/
	static void pxe_menu_draw_item ( struct pxe_menu *menu,
	unsigned int index, int selected ) {
	char buf[COLS+1];
	size_t len;
	unsigned int row;

	/* Prepare space-padded row content */
	len = snprintf ( buf, sizeof ( buf ), " %c. %s",
	( 'A' + index ), menu->items[index].desc );
	while ( len < ( sizeof ( buf ) - 1 ) )
	buf[len++] = ' ';
	buf[ sizeof ( buf ) - 1 ] = '\0';

	/* Draw row */
	row = ( LINES - menu->num_items + index );
	color_set ( ( selected ? CPAIR_PXE : CPAIR_DEFAULT ), NULL );
	mvprintw ( row, 0, "%s", buf );
	move ( row, 1 );
	}

	/**
	* Make selection from PXE boot menu
	*
	* @v menu PXE boot menu
	* @ret rc Return status code
	*/
	static int pxe_menu_select ( struct pxe_menu *menu ) {
	int key;
	unsigned int key_selection;
	unsigned int i;
	int rc = 0;

	/* Initialise UI */
	initscr();
	start_color();
	color_set ( CPAIR_DEFAULT, NULL );

	/* Draw initial menu */
	for ( i = 0 ; i < menu->num_items ; i++ )
	printf ( "\n" );
	for ( i = 0 ; i < menu->num_items ; i++ )
	pxe_menu_draw_item ( menu, ( menu->num_items - i - 1 ), 0 );

	while ( 1 ) {

	/* Highlight currently selected item */
	pxe_menu_draw_item ( menu, menu->selection, 1 );

	/* Wait for keyboard input */
	key = getkey ( 0 );

	/* Unhighlight currently selected item */
	pxe_menu_draw_item ( menu, menu->selection, 0 );

	/* Act upon key */
	if ( ( key == CR ) \|\| ( key == LF ) ) {
	pxe_menu_draw_item ( menu, menu->selection, 1 );
	break;
	} else if ( ( key == CTRL_C ) \|\| ( key == ESC ) ) {
	rc = -ECANCELED;
	break;
	} else if ( key == KEY_UP ) {
	if ( menu->selection > 0 )
	menu->selection--;
	} else if ( key == KEY_DOWN ) {
	if ( menu->selection < ( menu->num_items - 1 ) )
	menu->selection++;
	} else if ( ( key < KEY_MIN ) &&
	( ( key_selection = ( toupper ( key ) - 'A' ) )
	< menu->num_items ) ) {
	menu->selection = key_selection;
	pxe_menu_draw_item ( menu, menu->selection, 1 );
	break;
	}
	}

	/* Shut down UI */
	endwin();

	return rc;
	}

	/**
	* Prompt for (and make selection from) PXE boot menu
	*
	* @v menu PXE boot menu
	* @ret rc Return status code
	*/
	static int pxe_menu_prompt_and_select ( struct pxe_menu *menu ) {
	unsigned long start = currticks();
	unsigned long now;
	unsigned long elapsed;
	size_t len = 0;
	int key;
	int rc = 0;

	/* Display menu immediately, if specified to do so */
	if ( menu->timeout < 0 ) {
	if ( menu->prompt )
	printf ( "%s\n", menu->prompt );
	return pxe_menu_select ( menu );
	}

	/* Display prompt, if specified */
	if ( menu->prompt )
	printf ( "%s", menu->prompt );

	/* Wait for timeout, if specified */
	while ( menu->timeout > 0 ) {
	if ( ! len )
	len = printf ( " (%d)", menu->timeout );
	if ( iskey() ) {
	key = getkey ( 0 );
	if ( key == KEY_F8 ) {
	/* Display menu */
	printf ( "\n" );
	return pxe_menu_select ( menu );
	} else if ( ( key == CTRL_C ) \|\| ( key == ESC ) ) {
	/* Abort */
	rc = -ECANCELED;
	break;
	} else {
	/* Stop waiting */
	break;
	}
	}
	now = currticks();
	elapsed = ( now - start );
	if ( elapsed >= TICKS_PER_SEC ) {
	menu->timeout -= 1;
	do {
	printf ( "\b \b" );
	} while ( --len );
	start = now;
	}
	}

	/* Return with default option selected */
	printf ( "\n" );
	return rc;
	}

	/**
	* Boot using PXE boot menu
	*
	* @ret rc Return status code
	*
	* Note that a success return status indicates that a PXE boot menu
	* item has been selected, and that the DHCP session should perform a
	* boot server request/ack.
	*/
	int pxe_menu_boot ( struct net_device *netdev ) {
	struct pxe_menu *menu;
	unsigned int pxe_type;
	struct settings *pxebs_settings;
	struct uri *uri;
	int rc;

	/* Parse and allocate boot menu */
	if ( ( rc = pxe_menu_parse ( &menu ) ) != 0 )
	return rc;

	/* Make selection from boot menu */
	if ( ( rc = pxe_menu_prompt_and_select ( menu ) ) != 0 ) {
	free ( menu );
	return rc;
	}
	pxe_type = menu->items[menu->selection].type;

	/* Free boot menu */
	free ( menu );

	/* Return immediately if local boot selected */
	if ( ! pxe_type )
	return 0;

	/* Attempt PXE Boot Server Discovery */
	if ( ( rc = pxebs ( netdev, pxe_type ) ) != 0 )
	return rc;

	/* Fetch next server and filename */
	pxebs_settings = find_settings ( PXEBS_SETTINGS_NAME );
	assert ( pxebs_settings );
	uri = fetch_next_server_and_filename ( pxebs_settings );
	if ( ! uri )
	return -ENOMEM;

	/* Attempt boot */
	rc = uriboot ( uri, NULL, 0, 0, NULL, URIBOOT_NO_SAN );
	uri_put ( uri );
	return rc;
	}