efi_pxe.c

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/*
 * Copyright (C) 2015 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 (at your option) 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 );

#include <string.h>
#include <errno.h>
#include <ipxe/refcnt.h>
#include <ipxe/list.h>
#include <ipxe/netdevice.h>
#include <ipxe/fakedhcp.h>
#include <ipxe/process.h>
#include <ipxe/uri.h>
#include <ipxe/in.h>
#include <ipxe/socket.h>
#include <ipxe/tcpip.h>
#include <ipxe/xferbuf.h>
#include <ipxe/open.h>
#include <ipxe/dhcppkt.h>
#include <ipxe/udp.h>
#include <ipxe/efi/efi.h>
#include <ipxe/efi/efi_snp.h>
#include <ipxe/efi/efi_pxe.h>
#include <ipxe/efi/efi_null.h>
#include <ipxe/efi/Protocol/PxeBaseCode.h>
#include <ipxe/efi/Protocol/AppleNetBoot.h>
#include <usr/ifmgmt.h>
#include <config/general.h>

/** @file
 *
 * EFI PXE base code protocol
 *
 */

/* Downgrade user experience if configured to do so
 *
 * See comments in efi_snp.c
 */
#ifdef EFI_DOWNGRADE_UX
static EFI_GUID dummy_pxe_base_code_protocol_guid = {
        0x70647523, 0x2320, 0x7477,
        { 0x66, 0x20, 0x23, 0x6d, 0x6f, 0x72, 0x6f, 0x6e }
};
#define efi_pxe_base_code_protocol_guid dummy_pxe_base_code_protocol_guid
#endif

/** A PXE base code */
struct efi_pxe {
        /** Reference count */
        struct refcnt refcnt;
        /** Underlying network device */
        struct net_device *netdev;
        /** Name */
        const char *name;
        /** List of PXE base codes */
        struct list_head list;

        /** Installed handle */
        EFI_HANDLE handle;
        /** PXE base code protocol */
        EFI_PXE_BASE_CODE_PROTOCOL base;
        /** PXE base code mode */
        EFI_PXE_BASE_CODE_MODE mode;
        /** Apple NetBoot protocol */
        EFI_APPLE_NET_BOOT_PROTOCOL apple;

        /** TCP/IP network-layer protocol */
        struct tcpip_net_protocol *tcpip;
        /** Network-layer protocol */
        struct net_protocol *net;

        /** Data transfer buffer */
        struct xfer_buffer buf;

        /** (M)TFTP download interface */
        struct interface tftp;
        /** Block size (for TFTP) */
        size_t blksize;
        /** Overall return status */
        int rc;

        /** UDP interface */
        struct interface udp;
        /** List of received UDP packets */
        struct list_head queue;
        /** UDP interface closer process */
        struct process process;
};

/**
 * Free PXE base code
 *
 * @v refcnt            Reference count
 */
static void efi_pxe_free ( struct refcnt *refcnt ) {
        struct efi_pxe *pxe = container_of ( refcnt, struct efi_pxe, refcnt );

        netdev_put ( pxe->netdev );
        free ( pxe );
}

/** List of PXE base codes */
static LIST_HEAD ( efi_pxes );

/**
 * Locate PXE base code
 *
 * @v handle            EFI handle
 * @ret pxe             PXE base code, or NULL
 */
static struct efi_pxe * efi_pxe_find ( EFI_HANDLE handle ) {
        struct efi_pxe *pxe;

        /* Locate base code */
        list_for_each_entry ( pxe, &efi_pxes, list ) {
                if ( pxe->handle == handle )
                        return pxe;
        }

        return NULL;
}

/******************************************************************************
 *
 * IP addresses
 *
 ******************************************************************************
 */

/**
 * An EFI socket address
 *
 */
struct sockaddr_efi {
        /** Socket address family (part of struct @c sockaddr) */
        sa_family_t se_family;
        /** Flags (part of struct @c sockaddr_tcpip) */
        uint16_t se_flags;
        /** TCP/IP port (part of struct @c sockaddr_tcpip) */
        uint16_t se_port;
        /** Scope ID (part of struct @c sockaddr_tcpip)
         *
         * For link-local or multicast addresses, this is the network
         * device index.
         */
        uint16_t se_scope_id;
        /** IP address */
        EFI_IP_ADDRESS se_addr;
        /** Padding
         *
         * This ensures that a struct @c sockaddr_tcpip is large
         * enough to hold a socket address for any TCP/IP address
         * family.
         */
        char pad[ sizeof ( struct sockaddr ) -
                  ( sizeof ( sa_family_t ) /* se_family */ +
                    sizeof ( uint16_t ) /* se_flags */ +
                    sizeof ( uint16_t ) /* se_port */ +
                    sizeof ( uint16_t ) /* se_scope_id */ +
                    sizeof ( EFI_IP_ADDRESS ) /* se_addr */ ) ];
} __attribute__ (( packed, may_alias ));

/**
 * Populate socket address from EFI IP address
 *
 * @v pxe               PXE base code
 * @v ip                EFI IP address
 * @v sa                Socket address to fill in
 */
static void efi_pxe_ip_sockaddr ( struct efi_pxe *pxe, EFI_IP_ADDRESS *ip,
                                  struct sockaddr *sa ) {
        union {
                struct sockaddr sa;
                struct sockaddr_efi se;
        } *sockaddr = container_of ( sa, typeof ( *sockaddr ), sa );

        /* Initialise socket address */
        memset ( sockaddr, 0, sizeof ( *sockaddr ) );
        sockaddr->sa.sa_family = pxe->tcpip->sa_family;
        memcpy ( &sockaddr->se.se_addr, ip, pxe->net->net_addr_len );
        sockaddr->se.se_scope_id = pxe->netdev->scope_id;
}

/**
 * Transcribe EFI IP address (for debugging)
 *
 * @v pxe               PXE base code
 * @v ip                EFI IP address
 * @ret text            Transcribed IP address
 */
static const char * efi_pxe_ip_ntoa ( struct efi_pxe *pxe,
                                      EFI_IP_ADDRESS *ip ) {

        return pxe->net->ntoa ( ip );
}

/**
 * Populate local IP address
 *
 * @v pxe               PXE base code
 * @ret rc              Return status code
 */
static int efi_pxe_ip ( struct efi_pxe *pxe ) {
        EFI_PXE_BASE_CODE_MODE *mode = &pxe->mode;
        struct in_addr address;
        struct in_addr netmask;

        /* It's unclear which of the potentially many IPv6 addresses
         * is supposed to be used.
         */
        if ( mode->UsingIpv6 )
                return -ENOTSUP;

        /* Fetch IP address and subnet mask */
        fetch_ipv4_setting ( netdev_settings ( pxe->netdev ), &ip_setting,
                             &address );
        fetch_ipv4_setting ( netdev_settings ( pxe->netdev ), &netmask_setting,
                             &netmask );

        /* Populate IP address and subnet mask */
        memset ( &mode->StationIp, 0, sizeof ( mode->StationIp ) );
        memcpy ( &mode->StationIp, &address, sizeof ( address ) );
        memset ( &mode->SubnetMask, 0, sizeof ( mode->SubnetMask ) );
        memcpy ( &mode->SubnetMask, &netmask, sizeof ( netmask ) );

        return 0;
}

/**
 * Check if IP address matches filter
 *
 * @v pxe               PXE base code
 * @v ip                EFI IP address
 * @ret is_match        IP address matches filter
 */
static int efi_pxe_ip_filter ( struct efi_pxe *pxe, EFI_IP_ADDRESS *ip ) {
        EFI_PXE_BASE_CODE_MODE *mode = &pxe->mode;
        EFI_PXE_BASE_CODE_IP_FILTER *filter = &mode->IpFilter;
        uint8_t filters = filter->Filters;
        union {
                EFI_IP_ADDRESS ip;
                struct in_addr in;
                struct in6_addr in6;
        } *u = container_of ( ip, typeof ( *u ), ip );
        size_t addr_len = pxe->net->net_addr_len;
        unsigned int i;

        /* Match everything, if applicable */
        if ( filters & EFI_PXE_BASE_CODE_IP_FILTER_PROMISCUOUS )
                return 1;

        /* Match all multicasts, if applicable */
        if ( filters & EFI_PXE_BASE_CODE_IP_FILTER_PROMISCUOUS_MULTICAST ) {
                if ( mode->UsingIpv6 ) {
                        if ( IN6_IS_ADDR_MULTICAST ( &u->in6 ) )
                                return 1;
                } else {
                        if ( IN_IS_MULTICAST ( u->in.s_addr ) )
                                return 1;
                }
        }

        /* Match IPv4 broadcasts, if applicable */
        if ( filters & EFI_PXE_BASE_CODE_IP_FILTER_BROADCAST ) {
                if ( ( ! mode->UsingIpv6 ) &&
                     ( u->in.s_addr == INADDR_BROADCAST ) )
                        return 1;
        }

        /* Match station address, if applicable */
        if ( filters & EFI_PXE_BASE_CODE_IP_FILTER_STATION_IP ) {
                if ( memcmp ( ip, &mode->StationIp, addr_len ) == 0 )
                        return 1;
        }

        /* Match explicit addresses, if applicable */
        for ( i = 0 ; i < filter->IpCnt ; i++ ) {
                if ( memcmp ( ip, &filter->IpList[i], addr_len ) == 0 )
                        return 1;
        }

        return 0;
}

/******************************************************************************
 *
 * (M)TFTP download interface
 *
 ******************************************************************************
 */

/**
 * Close PXE (M)TFTP download interface
 *
 * @v pxe               PXE base code
 * @v rc                Reason for close
 */
static void efi_pxe_tftp_close ( struct efi_pxe *pxe, int rc ) {

        /* Restart interface */
        intf_restart ( &pxe->tftp, rc );

        /* Record overall status */
        pxe->rc = rc;
}

/**
 * Check PXE (M)TFTP download flow control window
 *
 * @v pxe               PXE base code
 * @ret len             Length of window
 */
static size_t efi_pxe_tftp_window ( struct efi_pxe *pxe ) {

        /* Return requested blocksize */
        return pxe->blksize;
}

/**
 * Receive new PXE (M)TFTP download data
 *
 * @v pxe               PXE base code
 * @v iobuf             I/O buffer
 * @v meta              Transfer metadata
 * @ret rc              Return status code
 */
static int efi_pxe_tftp_deliver ( struct efi_pxe *pxe,
                                  struct io_buffer *iobuf,
                                  struct xfer_metadata *meta ) {
        int rc;

        /* Deliver to data transfer buffer */
        if ( ( rc = xferbuf_deliver ( &pxe->buf, iob_disown ( iobuf ),
                                      meta ) ) != 0 )
                goto err_deliver;

        return 0;

 err_deliver:
        efi_pxe_tftp_close ( pxe, rc );
        return rc;
}

/** PXE file data transfer interface operations */
static struct interface_operation efi_pxe_tftp_operations[] = {
        INTF_OP ( xfer_deliver, struct efi_pxe *, efi_pxe_tftp_deliver ),
        INTF_OP ( xfer_window, struct efi_pxe *, efi_pxe_tftp_window ),
        INTF_OP ( intf_close, struct efi_pxe *, efi_pxe_tftp_close ),
};

/** PXE file data transfer interface descriptor */
static struct interface_descriptor efi_pxe_tftp_desc =
        INTF_DESC ( struct efi_pxe, tftp, efi_pxe_tftp_operations );

/**
 * Open (M)TFTP download interface
 *
 * @v pxe               PXE base code
 * @v ip                EFI IP address
 * @v filename          Filename
 * @ret rc              Return status code
 */
static int efi_pxe_tftp_open ( struct efi_pxe *pxe, EFI_IP_ADDRESS *ip,
                               const char *filename ) {
        struct sockaddr server;
        struct uri *uri;
        int rc;

        /* Parse server address and filename */
        efi_pxe_ip_sockaddr ( pxe, ip, &server );
        uri = pxe_uri ( &server, filename );
        if ( ! uri ) {
                DBGC ( pxe, "PXE %s could not parse %s:%s\n", pxe->name,
                       efi_pxe_ip_ntoa ( pxe, ip ), filename );
                rc = -ENOTSUP;
                goto err_parse;
        }

        /* Open URI */
        if ( ( rc = xfer_open_uri ( &pxe->tftp, uri ) ) != 0 ) {
                DBGC ( pxe, "PXE %s could not open: %s\n",
                       pxe->name, strerror ( rc ) );
                goto err_open;
        }

 err_open:
        uri_put ( uri );
 err_parse:
        return rc;
}

/******************************************************************************
 *
 * UDP interface
 *
 ******************************************************************************
 */

/** EFI UDP pseudo-header */
struct efi_pxe_udp_pseudo_header {
        /** Network-layer protocol */
        struct net_protocol *net;
        /** Destination port */
        uint16_t dest_port;
        /** Source port */
        uint16_t src_port;
} __attribute__ (( packed ));

/**
 * Close UDP interface
 *
 * @v pxe               PXE base code
 * @v rc                Reason for close
 */
static void efi_pxe_udp_close ( struct efi_pxe *pxe, int rc ) {
        struct io_buffer *iobuf;
        struct io_buffer *tmp;

        /* Release our claim on SNP devices, if applicable */
        if ( process_running ( &pxe->process ) )
                efi_snp_release();

        /* Stop process */
        process_del ( &pxe->process );

        /* Restart UDP interface */
        intf_restart ( &pxe->udp, rc );

        /* Flush any received UDP packets */
        list_for_each_entry_safe ( iobuf, tmp, &pxe->queue, list ) {
                list_del ( &iobuf->list );
                free_iob ( iobuf );
        }
}

/**
 * Receive UDP packet
 *
 * @v pxe               PXE base code
 * @v iobuf             I/O buffer
 * @v meta              Data transfer metadata
 * @ret rc              Return status code
 */
static int efi_pxe_udp_deliver ( struct efi_pxe *pxe, struct io_buffer *iobuf,
                                 struct xfer_metadata *meta ) {
        struct sockaddr_efi *se_src;
        struct sockaddr_efi *se_dest;
        struct tcpip_net_protocol *tcpip;
        struct net_protocol *net;
        struct efi_pxe_udp_pseudo_header *pshdr;
        size_t addr_len;
        size_t pshdr_len;
        int rc;

        /* Sanity checks */
        assert ( meta != NULL );
        se_src = ( ( struct sockaddr_efi * ) meta->src );
        assert ( se_src != NULL );
        se_dest = ( ( struct sockaddr_efi * ) meta->dest );
        assert ( se_dest != NULL );
        assert ( se_src->se_family == se_dest->se_family );

        /* Determine protocol */
        tcpip = tcpip_net_protocol ( se_src->se_family );
        if ( ! tcpip ) {
                rc = -ENOTSUP;
                goto err_unsupported;
        }
        net = tcpip->net_protocol;
        addr_len = net->net_addr_len;

        /* Construct pseudo-header */
        pshdr_len = ( sizeof ( *pshdr ) + ( 2 * addr_len ) );
        if ( ( rc = iob_ensure_headroom ( iobuf, pshdr_len ) ) != 0 )
                goto err_headroom;
        memcpy ( iob_push ( iobuf, addr_len ), &se_src->se_addr, addr_len );
        memcpy ( iob_push ( iobuf, addr_len ), &se_dest->se_addr, addr_len );
        pshdr = iob_push ( iobuf, sizeof ( *pshdr ) );
        pshdr->net = net;
        pshdr->dest_port = ntohs ( se_dest->se_port );
        pshdr->src_port = ntohs ( se_src->se_port );

        /* Add to queue */
        list_add_tail ( &iobuf->list, &pxe->queue );

        return 0;

 err_unsupported:
 err_headroom:
        free_iob ( iobuf );
        return rc;
}

/** PXE UDP interface operations */
static struct interface_operation efi_pxe_udp_operations[] = {
        INTF_OP ( xfer_deliver, struct efi_pxe *, efi_pxe_udp_deliver ),
        INTF_OP ( intf_close, struct efi_pxe *, efi_pxe_udp_close ),
};

/** PXE UDP interface descriptor */
static struct interface_descriptor efi_pxe_udp_desc =
        INTF_DESC ( struct efi_pxe, udp, efi_pxe_udp_operations );

/**
 * Open UDP interface
 *
 * @v pxe               PXE base code
 * @ret rc              Return status code
 */
static int efi_pxe_udp_open ( struct efi_pxe *pxe ) {
        int rc;

        /* If interface is already open, then cancel the scheduled close */
        if ( process_running ( &pxe->process ) ) {
                process_del ( &pxe->process );
                return 0;
        }

        /* Open promiscuous UDP interface */
        if ( ( rc = udp_open_promisc ( &pxe->udp ) ) != 0 ) {
                DBGC ( pxe, "PXE %s could not open UDP connection: %s\n",
                       pxe->name, strerror ( rc ) );
                return rc;
        }

        /* Claim network devices */
        efi_snp_claim();

        return 0;
}

/**
 * Schedule close of UDP interface
 *
 * @v pxe               PXE base code
 */
static void efi_pxe_udp_schedule_close ( struct efi_pxe *pxe ) {

        /* The EFI PXE base code protocol does not provide any
         * explicit UDP open/close methods.  To avoid the overhead of
         * reopening a socket for each read/write operation, we start
         * a process which will close the socket immediately if the
         * next call into iPXE is anything other than a UDP
         * read/write.
         */
        process_add ( &pxe->process );
}

/**
 * Scheduled close of UDP interface
 *
 * @v pxe               PXE base code
 */
static void efi_pxe_udp_scheduled_close ( struct efi_pxe *pxe ) {

        /* Close UDP interface */
        efi_pxe_udp_close ( pxe, 0 );
}

/** UDP close process descriptor */
static struct process_descriptor efi_pxe_process_desc =
        PROC_DESC_ONCE ( struct efi_pxe, process, efi_pxe_udp_scheduled_close );

/******************************************************************************
 *
 * Fake DHCP packets
 *
 ******************************************************************************
 */

/**
 * Name fake DHCP packet
 *
 * @v pxe               PXE base code
 * @v packet            Packet
 * @ret name            Name of packet
 */
static const char * efi_pxe_fake_name ( struct efi_pxe *pxe,
                                        EFI_PXE_BASE_CODE_PACKET *packet ) {
        EFI_PXE_BASE_CODE_MODE *mode = &pxe->mode;

        if ( packet == &mode->DhcpDiscover ) {
                return "DhcpDiscover";
        } else if ( packet == &mode->DhcpAck ) {
                return "DhcpAck";
        } else if ( packet == &mode->ProxyOffer ) {
                return "ProxyOffer";
        } else if ( packet == &mode->PxeDiscover ) {
                return "PxeDiscover";
        } else if ( packet == &mode->PxeReply ) {
                return "PxeReply";
        } else if ( packet == &mode->PxeBisReply ) {
                return "PxeBisReply";
        } else {
                return "<UNKNOWN>";
        }
}

/**
 * Construct fake DHCP packet and flag
 *
 * @v pxe               PXE base code
 * @v fake              Fake packet constructor
 * @v packet            Packet to fill in
 * @ret exists          Packet existence flag
 */
static BOOLEAN efi_pxe_fake ( struct efi_pxe *pxe,
                              int ( * fake ) ( struct net_device *netdev,
                                               void *data, size_t len ),
                              EFI_PXE_BASE_CODE_PACKET *packet ) {
        EFI_PXE_BASE_CODE_MODE *mode = &pxe->mode;
        struct dhcp_packet dhcppkt;
        struct dhcphdr *dhcphdr;
        unsigned int len;
        int rc;

        /* The fake packet constructors do not support IPv6 */
        if ( mode->UsingIpv6 )
                return FALSE;

        /* Attempt to construct packet */
        if ( ( rc = fake ( pxe->netdev, packet, sizeof ( *packet ) ) != 0 ) ) {
                DBGC ( pxe, "PXE %s could not fake %s: %s\n", pxe->name,
                       efi_pxe_fake_name ( pxe, packet ), strerror ( rc ) );
                return FALSE;
        }

        /* The WDS bootstrap wdsmgfw.efi has a buggy DHCPv4 packet
         * parser which does not correctly handle DHCP padding bytes.
         * Specifically, if a padding byte (i.e. a zero) is
         * encountered, the parse will first increment the pointer by
         * one to skip over the padding byte but will then drop into
         * the code path for handling normal options, which increments
         * the pointer by two to skip over the (already-skipped) type
         * field and the (non-existent) length field.
         *
         * The upshot of this bug in WDS is that the parser will fail
         * with an error 0xc0000023 if the number of spare bytes after
         * the end of the options is not an exact multiple of three.
         *
         * Work around this buggy parser by adding an explicit
         * DHCP_END tag.
         */
        dhcphdr = container_of ( &packet->Dhcpv4.BootpOpcode,
                                 struct dhcphdr, op );
        dhcppkt_init ( &dhcppkt, dhcphdr, sizeof ( *packet ) );
        len = dhcppkt_len ( &dhcppkt );
        if ( len < sizeof ( *packet ) )
                packet->Raw[len] = DHCP_END;

        return TRUE;
}

/**
 * Construct fake DHCP packets
 *
 * @v pxe               PXE base code
 */
static void efi_pxe_fake_all ( struct efi_pxe *pxe ) {
        EFI_PXE_BASE_CODE_MODE *mode = &pxe->mode;

        /* Construct fake packets */
        mode->DhcpDiscoverValid =
                efi_pxe_fake ( pxe, create_fakedhcpdiscover,
                               &mode->DhcpDiscover );
        mode->DhcpAckReceived =
                efi_pxe_fake ( pxe, create_fakedhcpack,
                               &mode->DhcpAck );
        mode->PxeReplyReceived =
                efi_pxe_fake ( pxe, create_fakepxebsack,
                               &mode->PxeReply );
}

/******************************************************************************
 *
 * Base code protocol
 *
 ******************************************************************************
 */

/**
 * Start PXE base code
 *
 * @v base              PXE base code protocol
 * @v use_ipv6          Use IPv6
 * @ret efirc           EFI status code
 */
static EFI_STATUS EFIAPI efi_pxe_start ( EFI_PXE_BASE_CODE_PROTOCOL *base,
                                         BOOLEAN use_ipv6 ) {
        struct efi_pxe *pxe = container_of ( base, struct efi_pxe, base );
        EFI_PXE_BASE_CODE_MODE *mode = &pxe->mode;
        struct tcpip_net_protocol *ipv6 = tcpip_net_protocol ( AF_INET6 );
        sa_family_t family = ( use_ipv6 ? AF_INET6 : AF_INET );
        int rc;

        DBGC ( pxe, "PXE %s START %s\n",
               pxe->name, ( use_ipv6 ? "IPv6" : "IPv4" ) );

        /* Initialise mode structure */
        memset ( mode, 0, sizeof ( *mode ) );
        mode->AutoArp = TRUE;
        mode->TTL = DEFAULT_TTL;
        mode->ToS = DEFAULT_ToS;
        mode->IpFilter.Filters =
                ( EFI_PXE_BASE_CODE_IP_FILTER_STATION_IP |
                  EFI_PXE_BASE_CODE_IP_FILTER_BROADCAST |
                  EFI_PXE_BASE_CODE_IP_FILTER_PROMISCUOUS |
                  EFI_PXE_BASE_CODE_IP_FILTER_PROMISCUOUS_MULTICAST );

        /* Check for IPv4/IPv6 support */
        mode->Ipv6Supported = ( ipv6 != NULL );
        mode->Ipv6Available = ( ipv6 != NULL );
        pxe->tcpip = tcpip_net_protocol ( family );
        if ( ! pxe->tcpip ) {
                DBGC ( pxe, "PXE %s has no support for %s\n",
                       pxe->name, socket_family_name ( family ) );
                return EFI_UNSUPPORTED;
        }
        pxe->net = pxe->tcpip->net_protocol;
        mode->UsingIpv6 = use_ipv6;

        /* Populate station IP address */
        if ( ( rc = efi_pxe_ip ( pxe ) ) != 0 )
                return rc;

        /* Construct fake DHCP packets */
        efi_pxe_fake_all ( pxe );

        /* Record that base code is started */
        mode->Started = TRUE;
        DBGC ( pxe, "PXE %s using %s\n",
               pxe->name, pxe->net->ntoa ( &mode->StationIp ) );

        return 0;
}

/**
 * Stop PXE base code
 *
 * @v base              PXE base code protocol
 * @ret efirc           EFI status code
 */
static EFI_STATUS EFIAPI efi_pxe_stop ( EFI_PXE_BASE_CODE_PROTOCOL *base ) {
        struct efi_pxe *pxe = container_of ( base, struct efi_pxe, base );
        EFI_PXE_BASE_CODE_MODE *mode = &pxe->mode;

        DBGC ( pxe, "PXE %s STOP\n", pxe->name );

        /* Record that base code is stopped */
        mode->Started = FALSE;

        /* Close TFTP */
        efi_pxe_tftp_close ( pxe, 0 );

        /* Close UDP */
        efi_pxe_udp_close ( pxe, 0 );

        return 0;
}

/**
 * Perform DHCP
 *
 * @v base              PXE base code protocol
 * @v sort              Offers should be sorted
 * @ret efirc           EFI status code
 */
static EFI_STATUS EFIAPI efi_pxe_dhcp ( EFI_PXE_BASE_CODE_PROTOCOL *base,
                                        BOOLEAN sort ) {
        struct efi_pxe *pxe = container_of ( base, struct efi_pxe, base );
        struct net_device *netdev = pxe->netdev;
        int rc;

        DBGC ( pxe, "PXE %s DHCP %s\n",
               pxe->name, ( sort ? "sorted" : "unsorted" ) );

        /* Claim network devices */
        efi_snp_claim();

        /* Initiate configuration */
        if ( ( rc = netdev_configure_all ( netdev ) ) != 0 ) {
                DBGC ( pxe, "PXE %s could not initiate configuration: %s\n",
                       pxe->name, strerror ( rc ) );
                goto err_configure;
        }

        /* Wait for configuration to complete (or time out) */
        while ( netdev_configuration_in_progress ( netdev ) )
                step();

        /* Report timeout if configuration failed */
        if ( ! netdev_configuration_ok ( netdev ) ) {
                rc = -ETIMEDOUT;
                goto err_timeout;
        }

        /* Update station IP address */
        if ( ( rc = efi_pxe_ip ( pxe ) ) != 0 )
                goto err_ip;

        /* Update faked DHCP packets */
        efi_pxe_fake_all ( pxe );

 err_ip:
 err_timeout:
 err_configure:
        efi_snp_release();
        return EFIRC ( rc );
}

/**
 * Perform boot server discovery
 *
 * @v base              PXE base code protocol
 * @v type              Boot server type
 * @v layer             Boot server layer
 * @v bis               Use boot integrity services
 * @v info              Additional information
 * @ret efirc           EFI status code
 */
static EFI_STATUS EFIAPI
efi_pxe_discover ( EFI_PXE_BASE_CODE_PROTOCOL *base, UINT16 type, UINT16 *layer,
                   BOOLEAN bis, EFI_PXE_BASE_CODE_DISCOVER_INFO *info ) {
        struct efi_pxe *pxe = container_of ( base, struct efi_pxe, base );
        EFI_IP_ADDRESS *ip;
        unsigned int i;

        DBGC ( pxe, "PXE %s DISCOVER type %d layer %d%s\n",
               pxe->name, type, *layer, ( bis ? " bis" : "" ) );
        if ( info ) {
                DBGC ( pxe, "%s%s%s%s %s",
                       ( info->UseMCast ? " mcast" : "" ),
                       ( info->UseBCast ? " bcast" : "" ),
                       ( info->UseUCast ? " ucast" : "" ),
                       ( info->MustUseList ? " list" : "" ),
                       efi_pxe_ip_ntoa ( pxe, &info->ServerMCastIp ) );
                for ( i = 0 ; i < info->IpCnt ; i++ ) {
                        ip = &info->SrvList[i].IpAddr;
                        DBGC ( pxe, " %d%s:%s", info->SrvList[i].Type,
                               ( info->SrvList[i].AcceptAnyResponse ?
                                 ":any" : "" ), efi_pxe_ip_ntoa ( pxe, ip ) );
                }
        }
        DBGC ( pxe, "\n" );

        /* Not used by any bootstrap I can find to test with */
        return EFI_UNSUPPORTED;
}

/**
 * Perform (M)TFTP
 *
 * @v base              PXE base code protocol
 * @v opcode            TFTP opcode
 * @v data              Data buffer
 * @v overwrite         Overwrite file
 * @v len               Length of data buffer
 * @v blksize           Block size
 * @v ip                Server address
 * @v filename          Filename
 * @v info              Additional information
 * @v callback          Pass packets to callback instead of data buffer
 * @ret efirc           EFI status code
 */
static EFI_STATUS EFIAPI
efi_pxe_mtftp ( EFI_PXE_BASE_CODE_PROTOCOL *base,
                EFI_PXE_BASE_CODE_TFTP_OPCODE opcode, VOID *data,
                BOOLEAN overwrite, UINT64 *len, UINTN *blksize,
                EFI_IP_ADDRESS *ip, UINT8 *filename,
                EFI_PXE_BASE_CODE_MTFTP_INFO *info, BOOLEAN callback ) {
        struct efi_pxe *pxe = container_of ( base, struct efi_pxe, base );
        int rc;

        DBGC ( pxe, "PXE %s MTFTP %d%s %p+%llx", pxe->name, opcode,
               ( overwrite ? " overwrite" : "" ), data, *len );
        if ( blksize )
                DBGC ( pxe, " blksize %zd", ( ( size_t ) *blksize ) );
        DBGC ( pxe, " %s:%s", efi_pxe_ip_ntoa ( pxe, ip ), filename );
        if ( info ) {
                DBGC ( pxe, " %s:%d:%d:%d:%d",
                       efi_pxe_ip_ntoa ( pxe, &info->MCastIp ),
                       info->CPort, info->SPort, info->ListenTimeout,
                       info->TransmitTimeout );
        }
        DBGC ( pxe, "%s\n", ( callback ? " callback" : "" ) );

        /* Fail unless operation is supported */
        if ( ! ( ( opcode == EFI_PXE_BASE_CODE_TFTP_READ_FILE ) ||
                 ( opcode == EFI_PXE_BASE_CODE_MTFTP_READ_FILE ) ) ) {
                DBGC ( pxe, "PXE %s unsupported MTFTP opcode %d\n",
                       pxe->name, opcode );
                rc = -ENOTSUP;
                goto err_opcode;
        }

        /* Claim network devices */
        efi_snp_claim();

        /* Determine block size.  Ignore the requested block size
         * unless we are using callbacks, since limiting HTTP to a
         * 512-byte TCP window is not sensible.
         */
        pxe->blksize = ( ( callback && blksize ) ? *blksize : -1UL );

        /* Initialise data transfer buffer */
        xferbuf_fixed_init ( &pxe->buf, data, *len );

        /* Open download */
        if ( ( rc = efi_pxe_tftp_open ( pxe, ip,
                                        ( ( const char * ) filename ) ) ) != 0 )
                goto err_open;

        /* Wait for download to complete */
        pxe->rc = -EINPROGRESS;
        while ( pxe->rc == -EINPROGRESS )
                step();
        if ( ( rc = pxe->rc ) != 0 ) {
                DBGC ( pxe, "PXE %s download failed: %s\n",
                       pxe->name, strerror ( rc ) );
                goto err_download;
        }

 err_download:
        efi_pxe_tftp_close ( pxe, rc );
 err_open:
        xferbuf_fixed_init ( &pxe->buf, NULL, 0 );
        efi_snp_release();
 err_opcode:
        return EFIRC ( rc );
}

/**
 * Transmit UDP packet
 *
 * @v base              PXE base code protocol
 * @v flags             Operation flags
 * @v dest_ip           Destination address
 * @v dest_port         Destination port
 * @v gateway           Gateway address
 * @v src_ip            Source address
 * @v src_port          Source port
 * @v hdr_len           Header length
 * @v hdr               Header data
 * @v len               Length
 * @v data              Data
 * @ret efirc           EFI status code
 */
static EFI_STATUS EFIAPI
efi_pxe_udp_write ( EFI_PXE_BASE_CODE_PROTOCOL *base, UINT16 flags,
                    EFI_IP_ADDRESS *dest_ip,
                    EFI_PXE_BASE_CODE_UDP_PORT *dest_port,
                    EFI_IP_ADDRESS *gateway, EFI_IP_ADDRESS *src_ip,
                    EFI_PXE_BASE_CODE_UDP_PORT *src_port,
                    UINTN *hdr_len, VOID *hdr, UINTN *len, VOID *data ) {
        struct efi_pxe *pxe = container_of ( base, struct efi_pxe, base );
        EFI_PXE_BASE_CODE_MODE *mode = &pxe->mode;
        struct io_buffer *iobuf;
        struct xfer_metadata meta;
        union {
                struct sockaddr_tcpip st;
                struct sockaddr sa;
        } dest;
        union {
                struct sockaddr_tcpip st;
                struct sockaddr sa;
        } src;
        int rc;

        DBGC2 ( pxe, "PXE %s UDP WRITE ", pxe->name );
        if ( src_ip )
                DBGC2 ( pxe, "%s", efi_pxe_ip_ntoa ( pxe, src_ip ) );
        DBGC2 ( pxe, ":" );
        if ( src_port &&
             ( ! ( flags & EFI_PXE_BASE_CODE_UDP_OPFLAGS_ANY_SRC_PORT ) ) ) {
                DBGC2 ( pxe, "%d", *src_port );
        } else {
                DBGC2 ( pxe, "*" );
        }
        DBGC2 ( pxe, "->%s:%d", efi_pxe_ip_ntoa ( pxe, dest_ip ), *dest_port );
        if ( gateway )
                DBGC2 ( pxe, " via %s", efi_pxe_ip_ntoa ( pxe, gateway ) );
        if ( hdr_len )
                DBGC2 ( pxe, " %p+%zx", hdr, ( ( size_t ) *hdr_len ) );
        DBGC2 ( pxe, " %p+%zx", data, ( ( size_t ) *len ) );
        if ( flags & EFI_PXE_BASE_CODE_UDP_OPFLAGS_MAY_FRAGMENT )
                DBGC2 ( pxe, " frag" );
        DBGC2 ( pxe, "\n" );

        /* Open UDP connection (if applicable) */
        if ( ( rc = efi_pxe_udp_open ( pxe ) ) != 0 )
                goto err_open;

        /* Construct destination address */
        efi_pxe_ip_sockaddr ( pxe, dest_ip, &dest.sa );
        dest.st.st_port = htons ( *dest_port );

        /* Construct source address */
        efi_pxe_ip_sockaddr ( pxe, ( src_ip ? src_ip : &mode->StationIp ),
                              &src.sa );
        if ( src_port &&
             ( ! ( flags & EFI_PXE_BASE_CODE_UDP_OPFLAGS_ANY_SRC_PORT ) ) ) {
                src.st.st_port = htons ( *src_port );
        } else {
                /* The API does not allow for a sensible concept of
                 * binding to a local port, so just use a random value.
                 */
                src.st.st_port = ( random() | htons ( 1024 ) );
                if ( src_port )
                        *src_port = ntohs ( src.st.st_port );
        }

        /* Allocate I/O buffer */
        iobuf = xfer_alloc_iob ( &pxe->udp,
                                 ( *len + ( hdr_len ? *hdr_len : 0 ) ) );
        if ( ! iobuf ) {
                rc = -ENOMEM;
                goto err_alloc;
        }

        /* Populate I/O buffer */
        if ( hdr_len )
                memcpy ( iob_put ( iobuf, *hdr_len ), hdr, *hdr_len );
        memcpy ( iob_put ( iobuf, *len ), data, *len );

        /* Construct metadata */
        memset ( &meta, 0, sizeof ( meta ) );
        meta.src = &src.sa;
        meta.dest = &dest.sa;
        meta.netdev = pxe->netdev;

        /* Deliver I/O buffer */
        if ( ( rc = xfer_deliver ( &pxe->udp, iob_disown ( iobuf ),
                                   &meta ) ) != 0 ) {
                DBGC ( pxe, "PXE %s could not transmit: %s\n",
                       pxe->name, strerror ( rc ) );
                goto err_deliver;
        }

 err_deliver:
        free_iob ( iobuf );
 err_alloc:
        efi_pxe_udp_schedule_close ( pxe );
 err_open:
        return EFIRC ( rc );
}

/**
 * Receive UDP packet
 *
 * @v base              PXE base code protocol
 * @v flags             Operation flags
 * @v dest_ip           Destination address
 * @v dest_port         Destination port
 * @v src_ip            Source address
 * @v src_port          Source port
 * @v hdr_len           Header length
 * @v hdr               Header data
 * @v len               Length
 * @v data              Data
 * @ret efirc           EFI status code
 */
static EFI_STATUS EFIAPI
efi_pxe_udp_read ( EFI_PXE_BASE_CODE_PROTOCOL *base, UINT16 flags,
                   EFI_IP_ADDRESS *dest_ip,
                   EFI_PXE_BASE_CODE_UDP_PORT *dest_port,
                   EFI_IP_ADDRESS *src_ip,
                   EFI_PXE_BASE_CODE_UDP_PORT *src_port,
                   UINTN *hdr_len, VOID *hdr, UINTN *len, VOID *data ) {
        struct efi_pxe *pxe = container_of ( base, struct efi_pxe, base );
        struct io_buffer *iobuf;
        struct efi_pxe_udp_pseudo_header *pshdr;
        EFI_IP_ADDRESS *actual_dest_ip;
        EFI_IP_ADDRESS *actual_src_ip;
        size_t addr_len;
        size_t frag_len;
        int rc;

        DBGC2 ( pxe, "PXE %s UDP READ ", pxe->name );
        if ( flags & EFI_PXE_BASE_CODE_UDP_OPFLAGS_USE_FILTER ) {
                DBGC2 ( pxe, "(filter)" );
        } else if ( flags & EFI_PXE_BASE_CODE_UDP_OPFLAGS_ANY_DEST_IP ) {
                DBGC2 ( pxe, "*" );
        } else if ( dest_ip ) {
                DBGC2 ( pxe, "%s", efi_pxe_ip_ntoa ( pxe, dest_ip ) );
        }
        DBGC2 ( pxe, ":" );
        if ( flags & EFI_PXE_BASE_CODE_UDP_OPFLAGS_ANY_DEST_PORT ) {
                DBGC2 ( pxe, "*" );
        } else if ( dest_port ) {
                DBGC2 ( pxe, "%d", *dest_port );
        } else {
                DBGC2 ( pxe, "<NULL>" );
        }
        DBGC2 ( pxe, "<-" );
        if ( flags & EFI_PXE_BASE_CODE_UDP_OPFLAGS_ANY_SRC_IP ) {
                DBGC2 ( pxe, "*" );
        } else if ( src_ip ) {
                DBGC2 ( pxe, "%s", efi_pxe_ip_ntoa ( pxe, src_ip ) );
        } else {
                DBGC2 ( pxe, "<NULL>" );
        }
        DBGC2 ( pxe, ":" );
        if ( flags & EFI_PXE_BASE_CODE_UDP_OPFLAGS_ANY_SRC_PORT ) {
                DBGC2 ( pxe, "*" );
        } else if ( src_port ) {
                DBGC2 ( pxe, "%d", *src_port );
        } else {
                DBGC2 ( pxe, "<NULL>" );
        }
        if ( hdr_len )
                DBGC2 ( pxe, " %p+%zx", hdr, ( ( size_t ) *hdr_len ) );
        DBGC2 ( pxe, " %p+%zx\n", data, ( ( size_t ) *len ) );

        /* Open UDP connection (if applicable) */
        if ( ( rc = efi_pxe_udp_open ( pxe ) ) != 0 )
                goto err_open;

        /* Try receiving a packet, if the queue is empty */
        if ( list_empty ( &pxe->queue ) )
                step();

        /* Remove first packet from the queue */
        iobuf = list_first_entry ( &pxe->queue, struct io_buffer, list );
        if ( ! iobuf ) {
                rc = -ETIMEDOUT; /* "no packet" */
                goto err_empty;
        }
        list_del ( &iobuf->list );

        /* Strip pseudo-header */
        pshdr = iobuf->data;
        addr_len = ( pshdr->net->net_addr_len );
        iob_pull ( iobuf, sizeof ( *pshdr ) );
        actual_dest_ip = iobuf->data;
        iob_pull ( iobuf, addr_len );
        actual_src_ip = iobuf->data;
        iob_pull ( iobuf, addr_len );
        DBGC2 ( pxe, "PXE %s UDP RX %s:%d", pxe->name,
                pshdr->net->ntoa ( actual_dest_ip ), pshdr->dest_port );
        DBGC2 ( pxe, "<-%s:%d len %#zx\n", pshdr->net->ntoa ( actual_src_ip ),
                pshdr->src_port, iob_len ( iobuf ) );

        /* Filter based on network-layer protocol */
        if ( pshdr->net != pxe->net ) {
                DBGC2 ( pxe, "PXE %s filtered out %s packet\n",
                        pxe->name, pshdr->net->name );
                rc = -ETIMEDOUT; /* "no packet" */
                goto err_filter;
        }

        /* Filter based on port numbers */
        if ( ! ( ( flags & EFI_PXE_BASE_CODE_UDP_OPFLAGS_ANY_DEST_PORT ) ||
                 ( dest_port && ( *dest_port == pshdr->dest_port ) ) ) ) {
                DBGC2 ( pxe, "PXE %s filtered out destination port %d\n",
                        pxe->name, pshdr->dest_port );
                rc = -ETIMEDOUT; /* "no packet" */
                goto err_filter;
        }
        if ( ! ( ( flags & EFI_PXE_BASE_CODE_UDP_OPFLAGS_ANY_SRC_PORT ) ||
                 ( src_port && ( *src_port == pshdr->src_port ) ) ) ) {
                DBGC2 ( pxe, "PXE %s filtered out source port %d\n",
                        pxe->name, pshdr->src_port );
                rc = -ETIMEDOUT; /* "no packet" */
                goto err_filter;
        }

        /* Filter based on source IP address */
        if ( ! ( ( flags & EFI_PXE_BASE_CODE_UDP_OPFLAGS_ANY_SRC_IP ) ||
                 ( src_ip &&
                   ( memcmp ( src_ip, actual_src_ip, addr_len ) == 0 ) ) ) ) {
                DBGC2 ( pxe, "PXE %s filtered out source IP %s\n",
                        pxe->name, pshdr->net->ntoa ( actual_src_ip ) );
                rc = -ETIMEDOUT; /* "no packet" */
                goto err_filter;
        }

        /* Filter based on destination IP address */
        if ( ! ( ( ( flags & EFI_PXE_BASE_CODE_UDP_OPFLAGS_USE_FILTER ) &&
                   efi_pxe_ip_filter ( pxe, actual_dest_ip ) ) ||
                 ( ( ! ( flags & EFI_PXE_BASE_CODE_UDP_OPFLAGS_USE_FILTER ) ) &&
                   ( ( flags & EFI_PXE_BASE_CODE_UDP_OPFLAGS_ANY_DEST_IP ) ||
                        ( dest_ip && ( memcmp ( dest_ip, actual_dest_ip,
                                                addr_len ) == 0 ) ) ) ) ) ) {
                DBGC2 ( pxe, "PXE %s filtered out destination IP %s\n",
                        pxe->name, pshdr->net->ntoa ( actual_dest_ip ) );
                rc = -ETIMEDOUT; /* "no packet" */
                goto err_filter;
        }

        /* Fill in addresses and port numbers */
        if ( dest_ip )
                memcpy ( dest_ip, actual_dest_ip, addr_len );
        if ( dest_port )
                *dest_port = pshdr->dest_port;
        if ( src_ip )
                memcpy ( src_ip, actual_src_ip, addr_len );
        if ( src_port )
                *src_port = pshdr->src_port;

        /* Fill in header, if applicable */
        if ( hdr_len ) {
                frag_len = iob_len ( iobuf );
                if ( frag_len > *hdr_len )
                        frag_len = *hdr_len;
                memcpy ( hdr, iobuf->data, frag_len );
                iob_pull ( iobuf, frag_len );
                *hdr_len = frag_len;
        }

        /* Fill in data buffer */
        frag_len = iob_len ( iobuf );
        if ( frag_len > *len )
                frag_len = *len;
        memcpy ( data, iobuf->data, frag_len );
        iob_pull ( iobuf, frag_len );
        *len = frag_len;

        /* Check for overflow */
        if ( iob_len ( iobuf ) ) {
                rc = -ERANGE;
                goto err_too_short;
        }

        /* Success */
        rc = 0;

 err_too_short:
 err_filter:
        free_iob ( iobuf );
 err_empty:
        efi_pxe_udp_schedule_close ( pxe );
 err_open:
        return EFIRC ( rc );
}

/**
 * Set receive filter
 *
 * @v base              PXE base code protocol
 * @v filter            Receive filter
 * @ret efirc           EFI status code
 */
static EFI_STATUS EFIAPI
efi_pxe_set_ip_filter ( EFI_PXE_BASE_CODE_PROTOCOL *base,
                        EFI_PXE_BASE_CODE_IP_FILTER *filter ) {
        struct efi_pxe *pxe = container_of ( base, struct efi_pxe, base );
        EFI_PXE_BASE_CODE_MODE *mode = &pxe->mode;
        unsigned int i;

        DBGC ( pxe, "PXE %s SET IP FILTER %02x",
               pxe->name, filter->Filters );
        for ( i = 0 ; i < filter->IpCnt ; i++ ) {
                DBGC ( pxe, " %s",
                       efi_pxe_ip_ntoa ( pxe, &filter->IpList[i] ) );
        }
        DBGC ( pxe, "\n" );

        /* Update filter */
        memcpy ( &mode->IpFilter, filter, sizeof ( mode->IpFilter ) );

        return 0;
}

/**
 * Resolve MAC address
 *
 * @v base              PXE base code protocol
 * @v ip                IP address
 * @v mac               MAC address to fill in
 * @ret efirc           EFI status code
 */
static EFI_STATUS EFIAPI efi_pxe_arp ( EFI_PXE_BASE_CODE_PROTOCOL *base,
                                       EFI_IP_ADDRESS *ip,
                                       EFI_MAC_ADDRESS *mac ) {
        struct efi_pxe *pxe = container_of ( base, struct efi_pxe, base );

        DBGC ( pxe, "PXE %s ARP %s %p\n",
               pxe->name, efi_pxe_ip_ntoa ( pxe, ip ), mac );

        /* Not used by any bootstrap I can find to test with */
        return EFI_UNSUPPORTED;
}

/**
 * Set parameters
 *
 * @v base              PXE base code protocol
 * @v autoarp           Automatic ARP packet generation
 * @v sendguid          Send GUID as client hardware address
 * @v ttl               IP time to live
 * @v tos               IP type of service
 * @v callback          Make callbacks
 * @ret efirc           EFI status code
 */
static EFI_STATUS EFIAPI
efi_pxe_set_parameters ( EFI_PXE_BASE_CODE_PROTOCOL *base,
                         BOOLEAN *autoarp, BOOLEAN *sendguid, UINT8 *ttl,
                         UINT8 *tos, BOOLEAN *callback ) {
        struct efi_pxe *pxe = container_of ( base, struct efi_pxe, base );
        EFI_PXE_BASE_CODE_MODE *mode = &pxe->mode;

        DBGC ( pxe, "PXE %s SET PARAMETERS", pxe->name );
        if ( autoarp )
                DBGC ( pxe, " %s", ( *autoarp ? "autoarp" : "noautoarp" ) );
        if ( sendguid )
                DBGC ( pxe, " %s", ( *sendguid ? "sendguid" : "sendmac" ) );
        if ( ttl )
                DBGC ( pxe, " ttl %d", *ttl );
        if ( tos )
                DBGC ( pxe, " tos %d", *tos );
        if ( callback ) {
                DBGC ( pxe, " %s",
                       ( *callback ? "callback" : "nocallback" ) );
        }
        DBGC ( pxe, "\n" );

        /* Update parameters */
        if ( autoarp )
                mode->AutoArp = *autoarp;
        if ( sendguid )
                mode->SendGUID = *sendguid;
        if ( ttl )
                mode->TTL = *ttl;
        if ( tos )
                mode->ToS = *tos;
        if ( callback )
                mode->MakeCallbacks = *callback;

        return 0;
}

/**
 * Set IP address
 *
 * @v base              PXE base code protocol
 * @v ip                IP address
 * @v netmask           Subnet mask
 * @ret efirc           EFI status code
 */
static EFI_STATUS EFIAPI
efi_pxe_set_station_ip ( EFI_PXE_BASE_CODE_PROTOCOL *base,
                         EFI_IP_ADDRESS *ip, EFI_IP_ADDRESS *netmask ) {
        struct efi_pxe *pxe = container_of ( base, struct efi_pxe, base );
        EFI_PXE_BASE_CODE_MODE *mode = &pxe->mode;

        DBGC ( pxe, "PXE %s SET STATION IP ", pxe->name );
        if ( ip )
                DBGC ( pxe, "%s", efi_pxe_ip_ntoa ( pxe, ip ) );
        if ( netmask )
                DBGC ( pxe, "/%s", efi_pxe_ip_ntoa ( pxe, netmask ) );
        DBGC ( pxe, "\n" );

        /* Update IP address and netmask */
        if ( ip )
                memcpy ( &mode->StationIp, ip, sizeof ( mode->StationIp ) );
        if ( netmask )
                memcpy ( &mode->SubnetMask, netmask, sizeof (mode->SubnetMask));

        return 0;
}

/**
 * Update cached DHCP packets
 *
 * @v base              PXE base code protocol
 * @v dhcpdisc_ok       DHCPDISCOVER is valid
 * @v dhcpack_ok        DHCPACK received
 * @v proxyoffer_ok     ProxyDHCPOFFER received
 * @v pxebsdisc_ok      PxeBsDISCOVER valid
 * @v pxebsack_ok       PxeBsACK received
 * @v pxebsbis_ok       PxeBsBIS received
 * @v dhcpdisc          DHCPDISCOVER packet
 * @v dhcpack           DHCPACK packet
 * @v proxyoffer        ProxyDHCPOFFER packet
 * @v pxebsdisc         PxeBsDISCOVER packet
 * @v pxebsack          PxeBsACK packet
 * @v pxebsbis          PxeBsBIS packet
 * @ret efirc           EFI status code
 */
static EFI_STATUS EFIAPI
efi_pxe_set_packets ( EFI_PXE_BASE_CODE_PROTOCOL *base, BOOLEAN *dhcpdisc_ok,
                      BOOLEAN *dhcpack_ok, BOOLEAN *proxyoffer_ok,
                      BOOLEAN *pxebsdisc_ok, BOOLEAN *pxebsack_ok,
                      BOOLEAN *pxebsbis_ok, EFI_PXE_BASE_CODE_PACKET *dhcpdisc,
                      EFI_PXE_BASE_CODE_PACKET *dhcpack,
                      EFI_PXE_BASE_CODE_PACKET *proxyoffer,
                      EFI_PXE_BASE_CODE_PACKET *pxebsdisc,
                      EFI_PXE_BASE_CODE_PACKET *pxebsack,
                      EFI_PXE_BASE_CODE_PACKET *pxebsbis ) {
        struct efi_pxe *pxe = container_of ( base, struct efi_pxe, base );
        EFI_PXE_BASE_CODE_MODE *mode = &pxe->mode;

        DBGC ( pxe, "PXE %s SET PACKETS\n", pxe->name );

        /* Update fake packet flags */
        if ( dhcpdisc_ok )
                mode->DhcpDiscoverValid = *dhcpdisc_ok;
        if ( dhcpack_ok )
                mode->DhcpAckReceived = *dhcpack_ok;
        if ( proxyoffer_ok )
                mode->ProxyOfferReceived = *proxyoffer_ok;
        if ( pxebsdisc_ok )
                mode->PxeDiscoverValid = *pxebsdisc_ok;
        if ( pxebsack_ok )
                mode->PxeReplyReceived = *pxebsack_ok;
        if ( pxebsbis_ok )
                mode->PxeBisReplyReceived = *pxebsbis_ok;

        /* Update fake packet contents */
        if ( dhcpdisc )
                memcpy ( &mode->DhcpDiscover, dhcpdisc, sizeof ( *dhcpdisc ) );
        if ( dhcpack )
                memcpy ( &mode->DhcpAck, dhcpack, sizeof ( *dhcpack ) );
        if ( proxyoffer )
                memcpy ( &mode->ProxyOffer, proxyoffer, sizeof ( *proxyoffer ));
        if ( pxebsdisc )
                memcpy ( &mode->PxeDiscover, pxebsdisc, sizeof ( *pxebsdisc ) );
        if ( pxebsack )
                memcpy ( &mode->PxeReply, pxebsack, sizeof ( *pxebsack ) );
        if ( pxebsbis )
                memcpy ( &mode->PxeBisReply, pxebsbis, sizeof ( *pxebsbis ) );

        return 0;
}

/** PXE base code protocol */
static EFI_PXE_BASE_CODE_PROTOCOL efi_pxe_base_code_protocol = {
        .Revision       = EFI_PXE_BASE_CODE_PROTOCOL_REVISION,
        .Start          = efi_pxe_start,
        .Stop           = efi_pxe_stop,
        .Dhcp           = efi_pxe_dhcp,
        .Discover       = efi_pxe_discover,
        .Mtftp          = efi_pxe_mtftp,
        .UdpWrite       = efi_pxe_udp_write,
        .UdpRead        = efi_pxe_udp_read,
        .SetIpFilter    = efi_pxe_set_ip_filter,
        .Arp            = efi_pxe_arp,
        .SetParameters  = efi_pxe_set_parameters,
        .SetStationIp   = efi_pxe_set_station_ip,
        .SetPackets     = efi_pxe_set_packets,
};

/******************************************************************************
 *
 * Apple NetBoot protocol
 *
 ******************************************************************************
 */

/**
 * Get DHCP/BSDP response
 *
 * @v packet            Packet
 * @v len               Length of data buffer
 * @v data              Data buffer
 * @ret efirc           EFI status code
 */
static EFI_STATUS EFIAPI
efi_apple_get_response ( EFI_PXE_BASE_CODE_PACKET *packet, UINTN *len,
                         VOID *data ) {

        /* Check length */
        if ( *len < sizeof ( *packet ) ) {
                *len = sizeof ( *packet );
                return EFI_BUFFER_TOO_SMALL;
        }

        /* Copy packet */
        memcpy ( data, packet, sizeof ( *packet ) );
        *len = sizeof ( *packet );

        return EFI_SUCCESS;
}

/**
 * Get DHCP response
 *
 * @v apple             Apple NetBoot protocol
 * @v len               Length of data buffer
 * @v data              Data buffer
 * @ret efirc           EFI status code
 */
static EFI_STATUS EFIAPI
efi_apple_get_dhcp_response ( EFI_APPLE_NET_BOOT_PROTOCOL *apple,
                              UINTN *len, VOID *data ) {
        struct efi_pxe *pxe = container_of ( apple, struct efi_pxe, apple );

        return efi_apple_get_response ( &pxe->mode.DhcpAck, len, data );
}

/**
 * Get BSDP response
 *
 * @v apple             Apple NetBoot protocol
 * @v len               Length of data buffer
 * @v data              Data buffer
 * @ret efirc           EFI status code
 */
static EFI_STATUS EFIAPI
efi_apple_get_bsdp_response ( EFI_APPLE_NET_BOOT_PROTOCOL *apple,
                              UINTN *len, VOID *data ) {
        struct efi_pxe *pxe = container_of ( apple, struct efi_pxe, apple );

        return efi_apple_get_response ( &pxe->mode.PxeReply, len, data );
}

/** Apple NetBoot protocol */
static EFI_APPLE_NET_BOOT_PROTOCOL efi_apple_net_boot_protocol = {
        .GetDhcpResponse = efi_apple_get_dhcp_response,
        .GetBsdpResponse = efi_apple_get_bsdp_response,
};

/******************************************************************************
 *
 * Installer
 *
 ******************************************************************************
 */

/**
 * Install PXE base code protocol
 *
 * @v handle            EFI handle
 * @v netdev            Underlying network device
 * @ret rc              Return status code
 */
int efi_pxe_install ( EFI_HANDLE handle, struct net_device *netdev ) {
        EFI_BOOT_SERVICES *bs = efi_systab->BootServices;
        struct tcpip_net_protocol *ipv6 = tcpip_net_protocol ( AF_INET6 );
        struct efi_pxe *pxe;
        struct in_addr ip;
        BOOLEAN use_ipv6;
        int leak = 0;
        EFI_STATUS efirc;
        int rc;

        /* Allocate and initialise structure */
        pxe = zalloc ( sizeof ( *pxe ) );
        if ( ! pxe ) {
                rc = -ENOMEM;
                goto err_alloc;
        }
        ref_init ( &pxe->refcnt, efi_pxe_free );
        pxe->netdev = netdev_get ( netdev );
        pxe->name = netdev->name;
        pxe->handle = handle;
        memcpy ( &pxe->base, &efi_pxe_base_code_protocol, sizeof ( pxe->base ));
        pxe->base.Mode = &pxe->mode;
        memcpy ( &pxe->apple, &efi_apple_net_boot_protocol,
                 sizeof ( pxe->apple ) );
        intf_init ( &pxe->tftp, &efi_pxe_tftp_desc, &pxe->refcnt );
        intf_init ( &pxe->udp, &efi_pxe_udp_desc, &pxe->refcnt );
        INIT_LIST_HEAD ( &pxe->queue );
        process_init_stopped ( &pxe->process, &efi_pxe_process_desc,
                               &pxe->refcnt );

        /* Crude heuristic: assume that we prefer to use IPv4 if we
         * have an IPv4 address for the network device, otherwise
         * prefer IPv6 (if available).
         */
        fetch_ipv4_setting ( netdev_settings ( netdev ), &ip_setting, &ip );
        use_ipv6 = ( ip.s_addr ? FALSE : ( ipv6 != NULL ) );

        /* Start base code */
        efi_pxe_start ( &pxe->base, use_ipv6 );

        /* Install PXE base code protocol */
        if ( ( efirc = bs->InstallMultipleProtocolInterfaces (
                        &handle,
                        &efi_pxe_base_code_protocol_guid, &pxe->base,
                        &efi_apple_net_boot_protocol_guid, &pxe->apple,
                        NULL ) ) != 0 ) {
                rc = -EEFI ( efirc );
                DBGC ( pxe, "PXE %s could not install base code protocol: %s\n",
                       pxe->name, strerror ( rc ) );
                goto err_install_protocol;
        }

        /* Transfer reference to list and return */
        list_add_tail ( &pxe->list, &efi_pxes );
        DBGC ( pxe, "PXE %s installed for %s\n",
               pxe->name, efi_handle_name ( handle ) );
        return 0;

        if ( ( efirc = bs->UninstallMultipleProtocolInterfaces (
                        handle,
                        &efi_pxe_base_code_protocol_guid, &pxe->base,
                        &efi_apple_net_boot_protocol_guid, &pxe->apple,
                        NULL ) ) != 0 ) {
                DBGC ( pxe, "PXE %s could not uninstall: %s\n",
                       pxe->name, strerror ( -EEFI ( efirc ) ) );
                leak = 1;
        }
        efi_nullify_pxe ( &pxe->base );
        efi_nullify_apple ( &pxe->apple );
 err_install_protocol:
        if ( ! leak )
                ref_put ( &pxe->refcnt );
 err_alloc:
        if ( leak )
                DBGC ( pxe, "PXE %s nullified and leaked\n", pxe->name );
        return rc;
}

/**
 * Uninstall PXE base code protocol
 *
 * @v handle            EFI handle
 */
void efi_pxe_uninstall ( EFI_HANDLE handle ) {
        EFI_BOOT_SERVICES *bs = efi_systab->BootServices;
        struct efi_pxe *pxe;
        int leak = efi_shutdown_in_progress;
        EFI_STATUS efirc;

        /* Locate PXE base code */
        pxe = efi_pxe_find ( handle );
        if ( ! pxe ) {
                DBG ( "PXE could not find base code for %s\n",
                      efi_handle_name ( handle ) );
                return;
        }

        /* Stop base code */
        efi_pxe_stop ( &pxe->base );

        /* Uninstall PXE base code protocol */
        if ( ( ! efi_shutdown_in_progress ) &&
             ( ( efirc = bs->UninstallMultipleProtocolInterfaces (
                        handle,
                        &efi_pxe_base_code_protocol_guid, &pxe->base,
                        &efi_apple_net_boot_protocol_guid, &pxe->apple,
                        NULL ) ) != 0 ) ) {
                DBGC ( pxe, "PXE %s could not uninstall: %s\n",
                       pxe->name, strerror ( -EEFI ( efirc ) ) );
                leak = 1;
        }
        efi_nullify_pxe ( &pxe->base );
        efi_nullify_apple ( &pxe->apple );

        /* Remove from list and drop list's reference */
        list_del ( &pxe->list );
        if ( ! leak )
                ref_put ( &pxe->refcnt );

        /* Report leakage, if applicable */
        if ( leak && ( ! efi_shutdown_in_progress ) )
                DBGC ( pxe, "PXE %s nullified and leaked\n", pxe->name );
}