efi_cachedhcp.c

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/*
 * Copyright (C) 2021 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/cachedhcp.h>
#include <ipxe/efi/efi.h>
#include <ipxe/efi/efi_path.h>
#include <ipxe/efi/efi_cachedhcp.h>
#include <ipxe/efi/Protocol/PxeBaseCode.h>

/** @file
 *
 * EFI cached DHCP packet
 *
 */

/**
 * Record cached DHCP packet
 *
 * @v device            Device handle
 * @v path              Device path
 * @ret rc              Return status code
 */
int efi_cachedhcp_record ( EFI_HANDLE device,
                           EFI_DEVICE_PATH_PROTOCOL *path ) {
        EFI_BOOT_SERVICES *bs = efi_systab->BootServices;
        unsigned int vlan;
        union {
                EFI_PXE_BASE_CODE_PROTOCOL *pxe;
                void *interface;
        } pxe;
        EFI_PXE_BASE_CODE_MODE *mode;
        EFI_STATUS efirc;
        int rc;

        /* Get VLAN tag, if any */
        vlan = efi_path_vlan ( path );

        /* Look for a PXE base code instance on the image's device handle */
        if ( ( efirc = bs->OpenProtocol ( device,
                                          &efi_pxe_base_code_protocol_guid,
                                          &pxe.interface, efi_image_handle,
                                          NULL,
                                          EFI_OPEN_PROTOCOL_GET_PROTOCOL ))!=0){
                rc = -EEFI ( efirc );
                DBGC ( device, "EFI %s has no PXE base code instance: %s\n",
                       efi_handle_name ( device ), strerror ( rc ) );
                goto err_open;
        }

        /* Do not attempt to cache IPv6 packets */
        mode = pxe.pxe->Mode;
        if ( mode->UsingIpv6 ) {
                rc = -ENOTSUP;
                DBGC ( device, "EFI %s has IPv6 PXE base code\n",
                       efi_handle_name ( device ) );
                goto err_ipv6;
        }

        /* Record DHCPACK, if present */
        if ( mode->DhcpAckReceived &&
             ( ( rc = cachedhcp_record ( &cached_dhcpack, vlan,
                                         virt_to_user ( &mode->DhcpAck ),
                                         sizeof ( mode->DhcpAck ) ) ) != 0 ) ) {
                DBGC ( device, "EFI %s could not record DHCPACK: %s\n",
                       efi_handle_name ( device ), strerror ( rc ) );
                goto err_dhcpack;
        }

        /* Record ProxyDHCPOFFER, if present */
        if ( mode->ProxyOfferReceived &&
             ( ( rc = cachedhcp_record ( &cached_proxydhcp, vlan,
                                         virt_to_user ( &mode->ProxyOffer ),
                                         sizeof ( mode->ProxyOffer ) ) ) != 0)){
                DBGC ( device, "EFI %s could not record ProxyDHCPOFFER: %s\n",
                       efi_handle_name ( device ), strerror ( rc ) );
                goto err_proxydhcp;
        }

        /* Record PxeBSACK, if present */
        if ( mode->PxeReplyReceived &&
             ( ( rc = cachedhcp_record ( &cached_pxebs, vlan,
                                         virt_to_user ( &mode->PxeReply ),
                                         sizeof ( mode->PxeReply ) ) ) != 0)){
                DBGC ( device, "EFI %s could not record PXEBSACK: %s\n",
                       efi_handle_name ( device ), strerror ( rc ) );
                goto err_pxebs;
        }

        /* Success */
        rc = 0;

 err_pxebs:
 err_proxydhcp:
 err_dhcpack:
 err_ipv6:
        bs->CloseProtocol ( device, &efi_pxe_base_code_protocol_guid,
                            efi_image_handle, NULL );
 err_open:
        return rc;
}