mnpnet.c

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/*
 * Copyright (C) 2024 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 );
FILE_SECBOOT ( PERMITTED );

/** @file
 *
 * MNP NIC driver
 *
 */

#include <string.h>
#include <errno.h>
#include <ipxe/iobuf.h>
#include <ipxe/netdevice.h>
#include <ipxe/ethernet.h>
#include <ipxe/cachedhcp.h>
#include <ipxe/efi/efi.h>
#include <ipxe/efi/efi_driver.h>
#include <ipxe/efi/efi_service.h>
#include <ipxe/efi/efi_utils.h>
#include <ipxe/efi/mnpnet.h>
#include <ipxe/efi/Protocol/ManagedNetwork.h>

/** An MNP transmit or receive token */
struct mnp_token {
        /** MNP completion token */
        EFI_MANAGED_NETWORK_COMPLETION_TOKEN token;
        /** Token is owned by MNP */
        int busy;
};

/** An MNP NIC */
struct mnp_nic {
        /** EFI device */
        struct efi_device *efidev;
        /** Managed network protocol */
        EFI_MANAGED_NETWORK_PROTOCOL *mnp;
        /** Generic device */
        struct device dev;

        /** Transmit token */
        struct mnp_token tx;
        /** Transmit descriptor */
        EFI_MANAGED_NETWORK_TRANSMIT_DATA txdata;
        /** Transmit I/O buffer */
        struct io_buffer *txbuf;

        /** Receive token */
        struct mnp_token rx;
};

/**
 * Transmit or receive token event
 *
 * @v event             Event
 * @v context           Event context
 */
static VOID EFIAPI mnpnet_event ( EFI_EVENT event __unused, VOID *context ) {
        struct mnp_token *token = context;

        /* Sanity check */
        assert ( token->busy );

        /* Mark token as no longer owned by MNP */
        token->busy = 0;
}

/**
 * Transmit packet
 *
 * @v netdev            Network device
 * @v iobuf             I/O buffer
 * @ret rc              Return status code
 */
static int mnpnet_transmit ( struct net_device *netdev,
                             struct io_buffer *iobuf ) {
        struct mnp_nic *mnp = netdev->priv;
        struct ll_protocol *ll_protocol = netdev->ll_protocol;
        EFI_STATUS efirc;
        int rc;

        /* Do nothing if shutdown is in progress */
        if ( efi_shutdown_in_progress )
                return -ECANCELED;

        /* Defer the packet if there is already a transmission in progress */
        if ( mnp->txbuf ) {
                netdev_tx_defer ( netdev, iobuf );
                return 0;
        }

        /* Construct transmit token */
        mnp->txdata.DataLength =
                ( iob_len ( iobuf ) - ll_protocol->ll_header_len );
        mnp->txdata.HeaderLength = ll_protocol->ll_header_len;
        mnp->txdata.FragmentCount = 1;
        mnp->txdata.FragmentTable[0].FragmentLength = iob_len ( iobuf );
        mnp->txdata.FragmentTable[0].FragmentBuffer = iobuf->data;
        mnp->tx.token.Packet.TxData = &mnp->txdata;

        /* Record as in use */
        mnp->tx.busy = 1;

        /* Transmit packet */
        if ( ( efirc = mnp->mnp->Transmit ( mnp->mnp, &mnp->tx.token ) ) != 0 ){
                rc = -EEFI ( efirc );
                DBGC ( mnp, "MNP %s could not transmit: %s\n",
                       netdev->name, strerror ( rc ) );
                mnp->tx.busy = 0;
                return rc;
        }

        /* Record I/O buffer */
        mnp->txbuf = iobuf;

        return 0;
}

/**
 * Refill receive token
 *
 * @v netdev            Network device
 */
static void mnpnet_refill_rx ( struct net_device *netdev ) {
        struct mnp_nic *mnp = netdev->priv;
        EFI_STATUS efirc;
        int rc;

        /* Do nothing if receive token is still in use */
        if ( mnp->rx.busy )
                return;

        /* Mark as in use */
        mnp->rx.busy = 1;

        /* Queue receive token */
        if ( ( efirc = mnp->mnp->Receive ( mnp->mnp, &mnp->rx.token ) ) != 0 ) {
                rc = -EEFI ( efirc );
                DBGC ( mnp, "MNP %s could not receive: %s\n",
                       netdev->name, strerror ( rc ) );
                /* Wait for next refill */
                mnp->rx.busy = 0;
                return;
        }
}

/**
 * Poll for completed packets
 *
 * @v netdev            Network device
 */
static void mnpnet_poll_tx ( struct net_device *netdev ) {
        struct mnp_nic *mnp = netdev->priv;
        struct io_buffer *iobuf;
        EFI_STATUS efirc;
        int rc;

        /* Do nothing if transmit token is still in use */
        if ( mnp->tx.busy )
                return;

        /* Do nothing unless we have a completion */
        if ( ! mnp->txbuf )
                return;

        /* Get completion status */
        efirc = mnp->tx.token.Status;
        rc = ( efirc ? -EEFI ( efirc ) : 0 );

        /* Complete transmission */
        iobuf = mnp->txbuf;
        mnp->txbuf = NULL;
        netdev_tx_complete_err ( netdev, iobuf, rc );
}

/**
 * Poll for received packets
 *
 * @v netdev            Network device
 */
static void mnpnet_poll_rx ( struct net_device *netdev ) {
        EFI_BOOT_SERVICES *bs = efi_systab->BootServices;
        struct mnp_nic *mnp = netdev->priv;
        EFI_MANAGED_NETWORK_RECEIVE_DATA *rxdata;
        struct io_buffer *iobuf;
        size_t len;
        EFI_STATUS efirc;
        int rc;

        /* Do nothing unless we have a completion */
        if ( mnp->rx.busy )
                return;
        rxdata = mnp->rx.token.Packet.RxData;

        /* Get completion status */
        if ( ( efirc = mnp->rx.token.Status ) != 0 ) {
                rc = -EEFI ( efirc );
                netdev_rx_err ( netdev, NULL, rc );
                goto recycle;
        }

        /* Allocate and fill I/O buffer */
        len = rxdata->PacketLength;
        iobuf = alloc_iob ( len );
        if ( ! iobuf ) {
                netdev_rx_err ( netdev, NULL, -ENOMEM );
                goto recycle;
        }
        memcpy ( iob_put ( iobuf, len ), rxdata->MediaHeader, len );

        /* Hand off to network stack */
        netdev_rx ( netdev, iobuf );

 recycle:
        /* Recycle token */
        bs->SignalEvent ( rxdata->RecycleEvent );
}

/**
 * Poll for completed packets
 *
 * @v netdev            Network device
 */
static void mnpnet_poll ( struct net_device *netdev ) {
        struct mnp_nic *mnp = netdev->priv;

        /* Do nothing if shutdown is in progress */
        if ( efi_shutdown_in_progress )
                return;

        /* Poll interface */
        mnp->mnp->Poll ( mnp->mnp );

        /* Process any transmit completions */
        mnpnet_poll_tx ( netdev );

        /* Process any receive completions */
        mnpnet_poll_rx ( netdev );

        /* Refill receive token */
        mnpnet_refill_rx ( netdev );
}

/**
 * Open network device
 *
 * @v netdev            Network device
 * @ret rc              Return status code
 */
static int mnpnet_open ( struct net_device *netdev ) {
        EFI_BOOT_SERVICES *bs = efi_systab->BootServices;
        static EFI_MANAGED_NETWORK_CONFIG_DATA config = {
                .EnableUnicastReceive = TRUE,
                .EnableMulticastReceive = TRUE,
                .EnableBroadcastReceive = TRUE,
                .EnablePromiscuousReceive = TRUE,
                .FlushQueuesOnReset = TRUE,
                .DisableBackgroundPolling = TRUE,
        };
        struct mnp_nic *mnp = netdev->priv;
        EFI_STATUS efirc;
        int rc;

        /* Create transmit event */
        if ( ( efirc = bs->CreateEvent ( EVT_NOTIFY_SIGNAL, TPL_NOTIFY,
                                         mnpnet_event, &mnp->tx,
                                         &mnp->tx.token.Event ) ) != 0 ) {
                rc = -EEFI ( efirc );
                DBGC ( mnp, "MNP %s could not create TX event: %s\n",
                       netdev->name, strerror ( rc ) );
                goto err_tx_event;
        }

        /* Create receive event */
        if ( ( efirc = bs->CreateEvent ( EVT_NOTIFY_SIGNAL, TPL_NOTIFY,
                                         mnpnet_event, &mnp->rx,
                                         &mnp->rx.token.Event ) ) != 0 ) {
                rc = -EEFI ( efirc );
                DBGC ( mnp, "MNP %s could not create RX event: %s\n",
                       netdev->name, strerror ( rc ) );
                goto err_rx_event;
        }

        /* Configure MNP */
        if ( ( efirc = mnp->mnp->Configure ( mnp->mnp, &config ) ) != 0 ) {
                rc = -EEFI ( efirc );
                DBGC ( mnp, "MNP %s could not configure: %s\n",
                       netdev->name, strerror ( rc ) );
                goto err_configure;
        }

        /* Refill receive token */
        mnpnet_refill_rx ( netdev );

        return 0;

        mnp->mnp->Configure ( mnp->mnp, NULL );
 err_configure:
        bs->CloseEvent ( mnp->rx.token.Event );
 err_rx_event:
        bs->CloseEvent ( mnp->tx.token.Event );
 err_tx_event:
        return rc;
}

/**
 * Close network device
 *
 * @v netdev            Network device
 */
static void mnpnet_close ( struct net_device *netdev ) {
        EFI_BOOT_SERVICES *bs = efi_systab->BootServices;
        struct mnp_nic *mnp = netdev->priv;

        /* Reset MNP (unless whole system shutdown is in progress) */
        if ( ! efi_shutdown_in_progress )
                mnp->mnp->Configure ( mnp->mnp, NULL );

        /* Close events */
        bs->CloseEvent ( mnp->rx.token.Event );
        bs->CloseEvent ( mnp->tx.token.Event );

        /* Reset tokens */
        mnp->tx.busy = 0;
        mnp->rx.busy = 0;

        /* Discard any incomplete I/O buffer */
        if ( mnp->txbuf ) {
                netdev_tx_complete_err ( netdev, mnp->txbuf, -ECANCELED );
                mnp->txbuf = NULL;
        }
}

/** MNP network device operations */
static struct net_device_operations mnpnet_operations = {
        .open = mnpnet_open,
        .close = mnpnet_close,
        .transmit = mnpnet_transmit,
        .poll = mnpnet_poll,
};

/**
 * Attach driver to device
 *
 * @v efidev            EFI device
 * @ret rc              Return status code
 */
int mnpnet_start ( struct efi_device *efidev ) {
        EFI_HANDLE device = efidev->device;
        EFI_GUID *binding = &efi_managed_network_service_binding_protocol_guid;
        EFI_SIMPLE_NETWORK_MODE mode;
        struct net_device *netdev;
        struct mnp_nic *mnp;
        EFI_STATUS efirc;
        int rc;

        /* Allocate and initalise structure */
        netdev = alloc_etherdev ( sizeof ( *mnp ) );
        if ( ! netdev ) {
                rc = -ENOMEM;
                goto err_alloc;
        }
        netdev_init ( netdev, &mnpnet_operations );
        mnp = netdev->priv;
        mnp->efidev = efidev;
        efidev_set_drvdata ( efidev, netdev );

        /* Populate underlying device information */
        efi_device_info ( device, "MNP", &mnp->dev );
        mnp->dev.driver_name = "MNP";
        mnp->dev.parent = &efidev->dev;
        list_add ( &mnp->dev.siblings, &efidev->dev.children );
        INIT_LIST_HEAD ( &mnp->dev.children );
        netdev->dev = &mnp->dev;

        /* Create MNP child */
        if ( ( rc = efi_service_add ( device, binding,
                                      &efidev->child ) ) != 0 ) {
                DBGC ( mnp, "MNP %s could not create child: %s\n",
                       efi_handle_name ( device ), strerror ( rc ) );
                goto err_service;
        }

        /* Open MNP protocol */
        if ( ( rc = efi_open_by_driver ( efidev->child,
                                         &efi_managed_network_protocol_guid,
                                         &mnp->mnp ) ) != 0 ) {
                DBGC ( mnp, "MNP %s could not open MNP protocol: %s\n",
                       efi_handle_name ( device ), strerror ( rc ) );
                goto err_open;
        }

        /* Get configuration */
        efirc = mnp->mnp->GetModeData ( mnp->mnp, NULL, &mode );
        if ( ( efirc != 0 ) && ( efirc != EFI_NOT_STARTED ) ) {
                rc = -EEFI ( efirc );
                DBGC ( mnp, "MNP %s could not get mode data: %s\n",
                       efi_handle_name ( device ), strerror ( rc ) );
                goto err_mode;
        }

        /* Populate network device parameters */
        if ( mode.HwAddressSize != netdev->ll_protocol->hw_addr_len ) {
                DBGC ( device, "MNP %s has invalid hardware address length "
                       "%d\n", efi_handle_name ( device ), mode.HwAddressSize );
                rc = -ENOTSUP;
                goto err_hw_addr_len;
        }
        memcpy ( netdev->hw_addr, &mode.PermanentAddress,
                 netdev->ll_protocol->hw_addr_len );
        if ( mode.HwAddressSize != netdev->ll_protocol->ll_addr_len ) {
                DBGC ( device, "MNP %s has invalid link-layer address length "
                       "%d\n", efi_handle_name ( device ), mode.HwAddressSize );
                rc = -ENOTSUP;
                goto err_ll_addr_len;
        }
        memcpy ( netdev->ll_addr, &mode.CurrentAddress,
                 netdev->ll_protocol->ll_addr_len );

        /* Register network device */
        if ( ( rc = register_netdev ( netdev ) ) != 0 )
                goto err_register;
        DBGC ( mnp, "MNP %s registered as %s\n",
               efi_handle_name ( device ), netdev->name );

        /* Mark as link up: we don't handle link state */
        netdev_link_up ( netdev );

        return 0;

        unregister_netdev ( netdev );
 err_register:
 err_ll_addr_len:
 err_hw_addr_len:
 err_mode:
        efi_close_by_driver ( efidev->child,
                              &efi_managed_network_protocol_guid );
 err_open:
        efi_service_del ( device, binding, efidev->child );
 err_service:
        list_del ( &mnp->dev.siblings );
        netdev_nullify ( netdev );
        netdev_put ( netdev );
 err_alloc:
        return rc;
}

/**
 * Detach driver from device
 *
 * @v efidev            EFI device
  */
void mnpnet_stop ( struct efi_device *efidev ) {
        EFI_GUID *binding = &efi_managed_network_service_binding_protocol_guid;
        struct net_device *netdev = efidev_get_drvdata ( efidev );
        struct mnp_nic *mnp = netdev->priv;

        /* Unregister network device */
        unregister_netdev ( netdev );

        /* Close MNP protocol */
        efi_close_by_driver ( efidev->child,
                              &efi_managed_network_protocol_guid );

        /* Remove MNP child (unless whole system shutdown is in progress) */
        if ( ! efi_shutdown_in_progress )
                efi_service_del ( efidev->device, binding, efidev->child );

        /* Free network device */
        list_del ( &mnp->dev.siblings );
        netdev_nullify ( netdev );
        netdev_put ( netdev );
}

/**
 * Create temporary MNP network device
 *
 * @v handle            MNP service binding handle
 * @v netdev            Network device to fill in
 * @ret rc              Return status code
 */
int mnptemp_create ( EFI_HANDLE handle, struct net_device **netdev ) {
        struct efi_device *efidev;
        int rc;

        /* Create temporary EFI device */
        efidev = efidev_alloc ( handle );
        if ( ! efidev ) {
                DBGC ( handle, "MNP %s could not create temporary device\n",
                       efi_handle_name ( handle ) );
                rc = -ENOMEM;
                goto err_alloc;
        }

        /* Start temporary network device */
        if ( ( rc = mnpnet_start ( efidev ) ) != 0 ) {
                DBGC ( handle, "MNP %s could not start MNP: %s\n",
                       efi_handle_name ( handle ), strerror ( rc ) );
                goto err_start;
        }

        /* Fill in network device */
        *netdev = efidev_get_drvdata ( efidev );

        return 0;

        mnpnet_stop ( efidev );
 err_start:
        efidev_free ( efidev );
 err_alloc:
        return rc;
}

/**
 * Destroy temporary MNP network device
 *
 * @v netdev            Network device
 */
void mnptemp_destroy ( struct net_device *netdev ) {
        struct mnp_nic *mnp = netdev->priv;
        struct efi_device *efidev = mnp->efidev;

        /* Recycle any cached DHCP packet */
        cachedhcp_recycle ( netdev );

        /* Stop temporary network device */
        mnpnet_stop ( efidev );

        /* Free temporary EFI device */
        efidev_free ( efidev );
}