opengnsys_ipxe/src/interface/efi/efi_path.c

/*
 * Copyright (C) 2020 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.
 */

#include <stdlib.h>
#include <stdarg.h>
#include <string.h>
#include <byteswap.h>
#include <ipxe/netdevice.h>
#include <ipxe/vlan.h>
#include <ipxe/uri.h>
#include <ipxe/usb.h>
#include <ipxe/efi/efi.h>
#include <ipxe/efi/efi_driver.h>
#include <ipxe/efi/efi_path.h>

/** @file
 *
 * EFI device paths
 *
 */

/**
 * Find end of device path
 *
 * @v path		Path to device
 * @ret path_end	End of device path
 */
EFI_DEVICE_PATH_PROTOCOL * efi_path_end ( EFI_DEVICE_PATH_PROTOCOL *path ) {

	while ( path->Type != END_DEVICE_PATH_TYPE ) {
		path = ( ( ( void * ) path ) +
			 /* There's this amazing new-fangled thing known as
			  * a UINT16, but who wants to use one of those? */
			 ( ( path->Length[1] << 8 ) | path->Length[0] ) );
	}

	return path;
}

/**
 * Find length of device path (excluding terminator)
 *
 * @v path		Path to device
 * @ret path_len	Length of device path
 */
size_t efi_path_len ( EFI_DEVICE_PATH_PROTOCOL *path ) {
	EFI_DEVICE_PATH_PROTOCOL *end = efi_path_end ( path );

	return ( ( ( void * ) end ) - ( ( void * ) path ) );
}

/**
 * Concatenate EFI device paths
 *
 * @v ...		List of device paths (NULL terminated)
 * @ret path		Concatenated device path, or NULL on error
 *
 * The caller is responsible for eventually calling free() on the
 * allocated device path.
 */
EFI_DEVICE_PATH_PROTOCOL * efi_paths ( EFI_DEVICE_PATH_PROTOCOL *first, ... ) {
	EFI_DEVICE_PATH_PROTOCOL *path;
	EFI_DEVICE_PATH_PROTOCOL *src;
	EFI_DEVICE_PATH_PROTOCOL *dst;
	EFI_DEVICE_PATH_PROTOCOL *end;
	va_list args;
	size_t len;

	/* Calculate device path length */
	va_start ( args, first );
	len = 0;
	src = first;
	while ( src ) {
		len += efi_path_len ( src );
		src = va_arg ( args, EFI_DEVICE_PATH_PROTOCOL * );
	}
	va_end ( args );

	/* Allocate device path */
	path = zalloc ( len + sizeof ( *end ) );
	if ( ! path )
		return NULL;

	/* Populate device path */
	va_start ( args, first );
	dst = path;
	src = first;
	while ( src ) {
		len = efi_path_len ( src );
		memcpy ( dst, src, len );
		dst = ( ( ( void * ) dst ) + len );
		src = va_arg ( args, EFI_DEVICE_PATH_PROTOCOL * );
	}
	va_end ( args );
	end = dst;
	end->Type = END_DEVICE_PATH_TYPE;
	end->SubType = END_ENTIRE_DEVICE_PATH_SUBTYPE;
	end->Length[0] = sizeof ( *end );

	return path;
}

/**
 * Construct EFI device path for network device
 *
 * @v netdev		Network device
 * @ret path		EFI device path, or NULL on error
 *
 * The caller is responsible for eventually calling free() on the
 * allocated device path.
 */
EFI_DEVICE_PATH_PROTOCOL * efi_netdev_path ( struct net_device *netdev ) {
	struct efi_device *efidev;
	EFI_DEVICE_PATH_PROTOCOL *path;
	MAC_ADDR_DEVICE_PATH *macpath;
	VLAN_DEVICE_PATH *vlanpath;
	EFI_DEVICE_PATH_PROTOCOL *end;
	unsigned int tag;
	size_t prefix_len;
	size_t len;

	/* Find parent EFI device */
	efidev = efidev_parent ( netdev->dev );
	if ( ! efidev )
		return NULL;

	/* Calculate device path length */
	prefix_len = efi_path_len ( efidev->path );
	len = ( prefix_len + sizeof ( *macpath ) + sizeof ( *vlanpath ) +
		sizeof ( *end ) );

	/* Allocate device path */
	path = zalloc ( len );
	if ( ! path )
		return NULL;

	/* Construct device path */
	memcpy ( path, efidev->path, prefix_len );
	macpath = ( ( ( void * ) path ) + prefix_len );
	macpath->Header.Type = MESSAGING_DEVICE_PATH;
	macpath->Header.SubType = MSG_MAC_ADDR_DP;
	macpath->Header.Length[0] = sizeof ( *macpath );
	assert ( netdev->ll_protocol->ll_addr_len <
		 sizeof ( macpath->MacAddress ) );
	memcpy ( &macpath->MacAddress, netdev->ll_addr,
		 netdev->ll_protocol->ll_addr_len );
	macpath->IfType = ntohs ( netdev->ll_protocol->ll_proto );
	if ( ( tag = vlan_tag ( netdev ) ) ) {
		vlanpath = ( ( ( void * ) macpath ) + sizeof ( *macpath ) );
		vlanpath->Header.Type = MESSAGING_DEVICE_PATH;
		vlanpath->Header.SubType = MSG_VLAN_DP;
		vlanpath->Header.Length[0] = sizeof ( *vlanpath );
		vlanpath->VlanId = tag;
		end = ( ( ( void * ) vlanpath ) + sizeof ( *vlanpath ) );
	} else {
		end = ( ( ( void * ) macpath ) + sizeof ( *macpath ) );
	}
	end->Type = END_DEVICE_PATH_TYPE;
	end->SubType = END_ENTIRE_DEVICE_PATH_SUBTYPE;
	end->Length[0] = sizeof ( *end );

	return path;
}

/**
 * Construct EFI device path for URI
 *
 * @v uri		URI
 * @ret path		EFI device path, or NULL on error
 *
 * The caller is responsible for eventually calling free() on the
 * allocated device path.
 */
EFI_DEVICE_PATH_PROTOCOL * efi_uri_path ( struct uri *uri ) {
	EFI_DEVICE_PATH_PROTOCOL *path;
	EFI_DEVICE_PATH_PROTOCOL *end;
	URI_DEVICE_PATH *uripath;
	size_t uri_len;
	size_t uripath_len;
	size_t len;

	/* Calculate device path length */
	uri_len = ( format_uri ( uri, NULL, 0 ) + 1 /* NUL */ );
	uripath_len = ( sizeof ( *uripath ) + uri_len );
	len = ( uripath_len + sizeof ( *end ) );

	/* Allocate device path */
	path = zalloc ( len );
	if ( ! path )
		return NULL;

	/* Construct device path */
	uripath = ( ( void * ) path );
	uripath->Header.Type = MESSAGING_DEVICE_PATH;
	uripath->Header.SubType = MSG_URI_DP;
	uripath->Header.Length[0] = ( uripath_len & 0xff );
	uripath->Header.Length[1] = ( uripath_len >> 8 );
	format_uri ( uri, uripath->Uri, uri_len );
	end = ( ( ( void * ) path ) + uripath_len );
	end->Type = END_DEVICE_PATH_TYPE;
	end->SubType = END_ENTIRE_DEVICE_PATH_SUBTYPE;
	end->Length[0] = sizeof ( *end );

	return path;
}

/**
 * Construct EFI device path for USB function
 *
 * @v func		USB function
 * @ret path		EFI device path, or NULL on error
 *
 * The caller is responsible for eventually calling free() on the
 * allocated device path.
 */
EFI_DEVICE_PATH_PROTOCOL * efi_usb_path ( struct usb_function *func ) {
	struct usb_device *usb = func->usb;
	struct efi_device *efidev;
	EFI_DEVICE_PATH_PROTOCOL *path;
	EFI_DEVICE_PATH_PROTOCOL *end;
	USB_DEVICE_PATH *usbpath;
	unsigned int count;
	size_t prefix_len;
	size_t len;

	/* Sanity check */
	assert ( func->desc.count >= 1 );

	/* Find parent EFI device */
	efidev = efidev_parent ( &func->dev );
	if ( ! efidev )
		return NULL;

	/* Calculate device path length */
	count = ( usb_depth ( usb ) + 1 );
	prefix_len = efi_path_len ( efidev->path );
	len = ( prefix_len + ( count * sizeof ( *usbpath ) ) +
		sizeof ( *end ) );

	/* Allocate device path */
	path = zalloc ( len );
	if ( ! path )
		return NULL;

	/* Construct device path */
	memcpy ( path, efidev->path, prefix_len );
	end = ( ( ( void * ) path ) + len - sizeof ( *end ) );
	end->Type = END_DEVICE_PATH_TYPE;
	end->SubType = END_ENTIRE_DEVICE_PATH_SUBTYPE;
	end->Length[0] = sizeof ( *end );
	usbpath = ( ( ( void * ) end ) - sizeof ( *usbpath ) );
	usbpath->InterfaceNumber = func->interface[0];
	for ( ; usb ; usbpath--, usb = usb->port->hub->usb ) {
		usbpath->Header.Type = MESSAGING_DEVICE_PATH;
		usbpath->Header.SubType = MSG_USB_DP;
		usbpath->Header.Length[0] = sizeof ( *usbpath );
		usbpath->ParentPortNumber = ( usb->port->address - 1 );
	}

	return path;
}

/**
 * Describe object as an EFI device path
 *
 * @v intf		Interface
 * @ret path		EFI device path, or NULL
 *
 * The caller is responsible for eventually calling free() on the
 * allocated device path.
 */
EFI_DEVICE_PATH_PROTOCOL * efi_describe ( struct interface *intf ) {
	struct interface *dest;
	efi_describe_TYPE ( void * ) *op =
		intf_get_dest_op ( intf, efi_describe, &dest );
	void *object = intf_object ( dest );
	EFI_DEVICE_PATH_PROTOCOL *path;

	if ( op ) {
		path = op ( object );
	} else {
		path = NULL;
	}

	intf_put ( dest );
	return path;
}