snponly.c

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/*
 * Copyright (C) 2014 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 <string.h>
#include <errno.h>
#include <ipxe/init.h>
#include <ipxe/efi/efi.h>
#include <ipxe/efi/efi_driver.h>
#include <ipxe/efi/efi_utils.h>
#include <ipxe/efi/mnpnet.h>
#include <ipxe/efi/Protocol/SimpleNetwork.h>
#include <ipxe/efi/Protocol/NetworkInterfaceIdentifier.h>
#include "snpnet.h"
#include "nii.h"

/** @file
 *
 * EFI chainloaded-device-only driver
 *
 */

/** A chainloaded protocol */
struct chained_protocol {
        /** Protocol GUID */
        EFI_GUID *protocol;
        /**
         * Target device handle
         *
         * This is the uppermost handle on which the same protocol
         * instance is installed as we find on the loaded image's
         * device handle.
         *
         * We match against the protocol instance (rather than simply
         * matching against the device handle itself) because some
         * systems load us via a child of the underlying device, with
         * a duplicate protocol installed on the child handle.
         *
         * We record the handle rather than the protocol instance
         * pointer since the calls to DisconnectController() and
         * ConnectController() may end up uninstalling and
         * reinstalling the protocol instance.
         */
        EFI_HANDLE device;
};

/** Chainloaded SNP protocol */
static struct chained_protocol chained_snp = {
        .protocol = &efi_simple_network_protocol_guid,
};

/** Chainloaded NII protocol */
static struct chained_protocol chained_nii = {
        .protocol = &efi_nii31_protocol_guid,
};

/** Chainloaded MNP protocol */
static struct chained_protocol chained_mnp = {
        .protocol = &efi_managed_network_service_binding_protocol_guid,
};

/**
 * Locate chainloaded protocol
 *
 * @v chained           Chainloaded protocol
 */
static void chained_locate ( struct chained_protocol *chained ) {
        EFI_BOOT_SERVICES *bs = efi_systab->BootServices;
        EFI_HANDLE device = efi_loaded_image->DeviceHandle;
        EFI_HANDLE handle;
        void *match = NULL;
        void *interface;
        unsigned int skip;
        EFI_STATUS efirc;
        int rc;

        /* Identify target device handle */
        for ( skip = 0 ; ; skip++ ) {

                /* Locate handle supporting this protocol */
                if ( ( rc = efi_locate_device ( device, chained->protocol,
                                                &handle, skip ) ) != 0 ) {
                        if ( skip == 0 ) {
                                DBGC ( device, "CHAINED %s does not support "
                                       "%s: %s\n", efi_handle_name ( device ),
                                       efi_guid_ntoa ( chained->protocol ),
                                       strerror ( rc ) );
                        }
                        break;
                }

                /* Get protocol instance */
                if ( ( efirc = bs->OpenProtocol (
                                        handle, chained->protocol, &interface,
                                        efi_image_handle, handle,
                                        EFI_OPEN_PROTOCOL_GET_PROTOCOL )) != 0){
                        rc = -EEFI ( efirc );
                        DBGC ( device, "CHAINED %s could not open %s on ",
                               efi_handle_name ( device ),
                               efi_guid_ntoa ( chained->protocol ) );
                        DBGC ( device, "%s: %s\n",
                               efi_handle_name ( handle ), strerror ( rc ) );
                        break;
                }
                bs->CloseProtocol ( handle, chained->protocol,
                                    efi_image_handle, handle );

                /* Stop if we reach a non-matching protocol instance */
                if ( match && ( match != interface ) ) {
                        DBGC ( device, "CHAINED %s found non-matching %s on ",
                               efi_handle_name ( device ),
                               efi_guid_ntoa ( chained->protocol ) );
                        DBGC ( device, "%s\n", efi_handle_name ( handle ) );
                        break;
                }

                /* Record this handle */
                chained->device = handle;
                match = interface;
                DBGC ( device, "CHAINED %s found %s on ",
                       efi_handle_name ( device ),
                       efi_guid_ntoa ( chained->protocol ) );
                DBGC ( device, "%s\n", efi_handle_name ( chained->device ) );
        }
}

/**
 * Check to see if driver supports a device
 *
 * @v device            EFI device handle
 * @v chained           Chainloaded protocol
 * @ret rc              Return status code
 */
static int chained_supported ( EFI_HANDLE device,
                               struct chained_protocol *chained ) {
        EFI_BOOT_SERVICES *bs = efi_systab->BootServices;
        void *interface;
        EFI_STATUS efirc;
        int rc;

        /* Get protocol */
        if ( ( efirc = bs->OpenProtocol ( device, chained->protocol, &interface,
                                          efi_image_handle, device,
                                          EFI_OPEN_PROTOCOL_GET_PROTOCOL ))!=0){
                rc = -EEFI ( efirc );
                DBGCP ( device, "CHAINED %s is not a %s device\n",
                        efi_handle_name ( device ),
                        efi_guid_ntoa ( chained->protocol ) );
                goto err_open_protocol;
        }

        /* Ignore non-matching handles */
        if ( device != chained->device ) {
                DBGC2 ( device, "CHAINED %s is not the chainloaded %s\n",
                        efi_handle_name ( device ),
                        efi_guid_ntoa ( chained->protocol ) );
                rc = -ENOTTY;
                goto err_no_match;
        }

        /* Success */
        rc = 0;
        DBGC ( device, "CHAINED %s is the chainloaded %s\n",
               efi_handle_name ( device ),
               efi_guid_ntoa ( chained->protocol ) );

 err_no_match:
        bs->CloseProtocol ( device, chained->protocol, efi_image_handle,
                            device );
 err_open_protocol:
        return rc;
}

/**
 * Check to see if driver supports a device
 *
 * @v device            EFI device handle
 * @ret rc              Return status code
 */
static int snponly_supported ( EFI_HANDLE device ) {

        return chained_supported ( device, &chained_snp );
}

/**
 * Check to see if driver supports a device
 *
 * @v device            EFI device handle
 * @ret rc              Return status code
 */
static int niionly_supported ( EFI_HANDLE device ) {

        return chained_supported ( device, &chained_nii );
}

/**
 * Check to see if driver supports a device
 *
 * @v device            EFI device handle
 * @ret rc              Return status code
 */
static int mnponly_supported ( EFI_HANDLE device ) {

        return chained_supported ( device, &chained_mnp );
}

/** EFI SNP chainloading-device-only driver */
struct efi_driver snponly_driver __efi_driver ( EFI_DRIVER_NORMAL ) = {
        .name = "SNPONLY",
        .supported = snponly_supported,
        .start = snpnet_start,
        .stop = snpnet_stop,
};

/** EFI NII chainloading-device-only driver */
struct efi_driver niionly_driver __efi_driver ( EFI_DRIVER_NORMAL ) = {
        .name = "NIIONLY",
        .supported = niionly_supported,
        .start = nii_start,
        .stop = nii_stop,
};

/** EFI MNP chainloading-device-only driver */
struct efi_driver mnponly_driver __efi_driver ( EFI_DRIVER_NORMAL ) = {
        .name = "MNPONLY",
        .supported = mnponly_supported,
        .start = mnpnet_start,
        .stop = mnpnet_stop,
};

/**
 * Initialise EFI chainloaded-device-only driver
 *
 */
static void chained_init ( void ) {

        chained_locate ( &chained_snp );
        chained_locate ( &chained_nii );
        chained_locate ( &chained_mnp );
}

/** EFI chainloaded-device-only initialisation function */
struct init_fn chained_init_fn __init_fn ( INIT_LATE ) = {
        .initialise = chained_init,
};