grub-lakitu/grub-core/net/drivers/efi/efinet.c - cos/cobble - Git at Google

 /*
  *  GRUB  --  GRand Unified Bootloader
  *  Copyright (C) 2010,2011  Free Software Foundation, Inc.
  *
  *  GRUB 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 3 of the License, or
  *  (at your option) any later version.
  *
  *  GRUB 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 GRUB.  If not, see <http://www.gnu.org/licenses/>.
  */

 #include <grub/net/netbuff.h>
 #include <grub/dl.h>
 #include <grub/net.h>
 #include <grub/time.h>
 #include <grub/efi/api.h>
 #include <grub/efi/efi.h>
 #include <grub/i18n.h>

 GRUB_MOD_LICENSE ("GPLv3+");

 /* GUID.  */
 static grub_efi_guid_t net_io_guid = GRUB_EFI_SIMPLE_NETWORK_GUID;
 static grub_efi_guid_t pxe_io_guid = GRUB_EFI_PXE_GUID;

 static grub_err_t
 send_card_buffer (struct grub_net_card *dev,
 		  struct grub_net_buff *pack)
 {
   grub_efi_status_t st;
   grub_efi_simple_network_t *net = dev->efi_net;
   grub_uint64_t limit_time = grub_get_time_ms () + 4000;
   void *txbuf;

   if (dev->txbusy)
     while (1)
       {
 	txbuf = NULL;
 	st = efi_call_3 (net->get_status, net, 0, &txbuf);
 	if (st != GRUB_EFI_SUCCESS)
 	  return grub_error (GRUB_ERR_IO,
 			     N_("couldn't send network packet"));
 	/*
 	   Some buggy firmware could return an arbitrary address instead of the
 	   txbuf address we trasmitted, so just check that txbuf is non NULL
 	   for success.  This is ok because we open the SNP protocol in
 	   exclusive mode so we know we're the only ones transmitting on this
 	   box and since we only transmit one packet at a time we know our
 	   transmit was successfull.
 	 */
 	if (txbuf)
 	  {
 	    dev->txbusy = 0;
 	    break;
 	  }
 	if (limit_time < grub_get_time_ms ())
 	  return grub_error (GRUB_ERR_TIMEOUT,
 			     N_("couldn't send network packet"));
       }

   dev->last_pkt_size = (pack->tail - pack->data);
   if (dev->last_pkt_size > dev->mtu)
     dev->last_pkt_size = dev->mtu;

   grub_memcpy (dev->txbuf, pack->data, dev->last_pkt_size);

   st = efi_call_7 (net->transmit, net, 0, dev->last_pkt_size,
 		   dev->txbuf, NULL, NULL, NULL);
   if (st != GRUB_EFI_SUCCESS)
     return grub_error (GRUB_ERR_IO, N_("couldn't send network packet"));

   /*
      The card may have sent out the packet immediately - set txbusy
      to 0 in this case.
      Cases were observed where checking txbuf at the next call
      of send_card_buffer() is too late: 0 is returned in txbuf and
      we run in the GRUB_ERR_TIMEOUT case above.
      Perhaps a timeout in the FW has discarded the recycle buffer.
    */
   txbuf = NULL;
   st = efi_call_3 (net->get_status, net, 0, &txbuf);
   dev->txbusy = !(st == GRUB_EFI_SUCCESS && txbuf);

   return GRUB_ERR_NONE;
 }

 static struct grub_net_buff *
 get_card_packet (struct grub_net_card *dev)
 {
   grub_efi_simple_network_t *net = dev->efi_net;
   grub_err_t err;
   grub_efi_status_t st;
   grub_efi_uintn_t bufsize = dev->rcvbufsize;
   struct grub_net_buff *nb;
   int i;

   for (i = 0; i < 2; i++)
     {
       if (!dev->rcvbuf)
 	dev->rcvbuf = grub_malloc (dev->rcvbufsize);
       if (!dev->rcvbuf)
 	return NULL;

       st = efi_call_7 (net->receive, net, NULL, &bufsize,
 		       dev->rcvbuf, NULL, NULL, NULL);
       if (st != GRUB_EFI_BUFFER_TOO_SMALL)
 	break;
       dev->rcvbufsize = 2 * ALIGN_UP (dev->rcvbufsize > bufsize
 				      ? dev->rcvbufsize : bufsize, 64);
       grub_free (dev->rcvbuf);
       dev->rcvbuf = 0;
     }

   if (st != GRUB_EFI_SUCCESS)
     return NULL;

   nb = grub_netbuff_alloc (bufsize + 2);
   if (!nb)
     return NULL;

   /* Reserve 2 bytes so that 2 + 14/18 bytes of ethernet header is divisible
      by 4. So that IP header is aligned on 4 bytes. */
   if (grub_netbuff_reserve (nb, 2))
     {
       grub_netbuff_free (nb);
       return NULL;
     }
   grub_memcpy (nb->data, dev->rcvbuf, bufsize);
   err = grub_netbuff_put (nb, bufsize);
   if (err)
     {
       grub_netbuff_free (nb);
       return NULL;
     }

   return nb;
 }

 static grub_err_t
 open_card (struct grub_net_card *dev)
 {
   grub_efi_simple_network_t *net;

   /* Try to reopen SNP exlusively to close any active MNP protocol instance
      that may compete for packet polling
    */
   net = grub_efi_open_protocol (dev->efi_handle, &net_io_guid,
 				GRUB_EFI_OPEN_PROTOCOL_BY_EXCLUSIVE);
   if (net)
     {
       if (net->mode->state == GRUB_EFI_NETWORK_STOPPED
 	  && efi_call_1 (net->start, net) != GRUB_EFI_SUCCESS)
 	return grub_error (GRUB_ERR_NET_NO_CARD, "%s: net start failed",
 			   dev->name);

       if (net->mode->state == GRUB_EFI_NETWORK_STOPPED)
 	return grub_error (GRUB_ERR_NET_NO_CARD, "%s: card stopped",
 			   dev->name);

       if (net->mode->state == GRUB_EFI_NETWORK_STARTED
 	  && efi_call_3 (net->initialize, net, 0, 0) != GRUB_EFI_SUCCESS)
 	return grub_error (GRUB_ERR_NET_NO_CARD, "%s: net initialize failed",
 			   dev->name);

       /* Enable hardware receive filters if driver declares support for it.
 	 We need unicast and broadcast and additionaly all nodes and
 	 solicited multicast for IPv6. Solicited multicast is per-IPv6
 	 address and we currently do not have API to do it so simply
 	 try to enable receive of all multicast packets or evertyhing in
 	 the worst case (i386 PXE driver always enables promiscuous too).

 	 This does trust firmware to do what it claims to do.
        */
       if (net->mode->receive_filter_mask)
 	{
 	  grub_uint32_t filters = GRUB_EFI_SIMPLE_NETWORK_RECEIVE_UNICAST   |
 				  GRUB_EFI_SIMPLE_NETWORK_RECEIVE_BROADCAST |
 				  GRUB_EFI_SIMPLE_NETWORK_RECEIVE_PROMISCUOUS_MULTICAST;

 	  filters &= net->mode->receive_filter_mask;
 	  if (!(filters & GRUB_EFI_SIMPLE_NETWORK_RECEIVE_PROMISCUOUS_MULTICAST))
 	    filters |= (net->mode->receive_filter_mask &
 			GRUB_EFI_SIMPLE_NETWORK_RECEIVE_PROMISCUOUS);

 	  efi_call_6 (net->receive_filters, net, filters, 0, 0, 0, NULL);
 	}

       efi_call_4 (grub_efi_system_table->boot_services->close_protocol,
 		  dev->efi_net, &net_io_guid,
 		  grub_efi_image_handle, dev->efi_handle);
       dev->efi_net = net;
     }

   /* If it failed we just try to run as best as we can */
   return GRUB_ERR_NONE;
 }

 static void
 close_card (struct grub_net_card *dev)
 {
   efi_call_1 (dev->efi_net->shutdown, dev->efi_net);
   efi_call_1 (dev->efi_net->stop, dev->efi_net);
   efi_call_4 (grub_efi_system_table->boot_services->close_protocol,
 	      dev->efi_net, &net_io_guid,
 	      grub_efi_image_handle, dev->efi_handle);
 }

 static struct grub_net_card_driver efidriver =
   {
     .name = "efinet",
     .open = open_card,
     .close = close_card,
     .send = send_card_buffer,
     .recv = get_card_packet
   };

 grub_efi_handle_t
 grub_efinet_get_device_handle (struct grub_net_card *card)
 {
   if (!card || card->driver != &efidriver)
     return 0;
   return card->efi_handle;
 }

 static void
 grub_efinet_findcards (void)
 {
   grub_efi_uintn_t num_handles;
   grub_efi_handle_t *handles;
   grub_efi_handle_t *handle;
   int i = 0;

   /* Find handles which support the disk io interface.  */
   handles = grub_efi_locate_handle (GRUB_EFI_BY_PROTOCOL, &net_io_guid,
 				    0, &num_handles);
   if (! handles)
     return;
   for (handle = handles; num_handles--; handle++)
     {
       grub_efi_simple_network_t *net;
       struct grub_net_card *card;
       grub_efi_device_path_t *dp, *parent = NULL, *child = NULL;

       /* EDK2 UEFI PXE driver creates IPv4 and IPv6 messaging devices as
 	 children of main MAC messaging device. We only need one device with
 	 bound SNP per physical card, otherwise they compete with each other
 	 when polling for incoming packets.
        */
       dp = grub_efi_get_device_path (*handle);
       if (!dp)
 	continue;
       for (; ! GRUB_EFI_END_ENTIRE_DEVICE_PATH (dp); dp = GRUB_EFI_NEXT_DEVICE_PATH (dp))
 	{
 	  parent = child;
 	  child = dp;
 	}
       if (child
 	  && GRUB_EFI_DEVICE_PATH_TYPE (child) == GRUB_EFI_MESSAGING_DEVICE_PATH_TYPE
 	  && (GRUB_EFI_DEVICE_PATH_SUBTYPE (child) == GRUB_EFI_IPV4_DEVICE_PATH_SUBTYPE
 	      || GRUB_EFI_DEVICE_PATH_SUBTYPE (child) == GRUB_EFI_IPV6_DEVICE_PATH_SUBTYPE)
 	  && parent
 	  && GRUB_EFI_DEVICE_PATH_TYPE (parent) == GRUB_EFI_MESSAGING_DEVICE_PATH_TYPE
 	  && GRUB_EFI_DEVICE_PATH_SUBTYPE (parent) == GRUB_EFI_MAC_ADDRESS_DEVICE_PATH_SUBTYPE)
 	continue;

       net = grub_efi_open_protocol (*handle, &net_io_guid,
 				    GRUB_EFI_OPEN_PROTOCOL_GET_PROTOCOL);
       if (! net)
 	/* This should not happen... Why?  */
 	continue;

       if (net->mode->state == GRUB_EFI_NETWORK_STOPPED
 	  && efi_call_1 (net->start, net) != GRUB_EFI_SUCCESS)
 	continue;

       if (net->mode->state == GRUB_EFI_NETWORK_STOPPED)
 	continue;

       if (net->mode->state == GRUB_EFI_NETWORK_STARTED
 	  && efi_call_3 (net->initialize, net, 0, 0) != GRUB_EFI_SUCCESS)
 	continue;

       card = grub_zalloc (sizeof (struct grub_net_card));
       if (!card)
 	{
 	  grub_print_error ();
 	  grub_free (handles);
 	  return;
 	}

       card->mtu = net->mode->max_packet_size;
       card->txbufsize = ALIGN_UP (card->mtu, 64) + 256;
       card->txbuf = grub_zalloc (card->txbufsize);
       if (!card->txbuf)
 	{
 	  grub_print_error ();
 	  grub_free (handles);
 	  grub_free (card);
 	  return;
 	}
       card->txbusy = 0;

       card->rcvbufsize = ALIGN_UP (card->mtu, 64) + 256;

       card->name = grub_xasprintf ("efinet%d", i++);
       card->driver = &efidriver;
       card->flags = 0;
       card->default_address.type = GRUB_NET_LINK_LEVEL_PROTOCOL_ETHERNET;
       grub_memcpy (card->default_address.mac,
 		   net->mode->current_address,
 		   sizeof (card->default_address.mac));
       card->efi_net = net;
       card->efi_handle = *handle;

       grub_net_card_register (card);
     }
   grub_free (handles);
 }

 static void
 grub_efi_net_config_real (grub_efi_handle_t hnd, char **device,
 			  char **path)
 {
   struct grub_net_card *card;
   grub_efi_device_path_t *dp;

   dp = grub_efi_get_device_path (hnd);
   if (! dp)
     return;

   FOR_NET_CARDS (card)
   {
     grub_efi_device_path_t *cdp;
     struct grub_efi_pxe *pxe;
     struct grub_efi_pxe_mode *pxe_mode;
     if (card->driver != &efidriver)
       continue;
     cdp = grub_efi_get_device_path (card->efi_handle);
     if (! cdp)
       continue;
     if (grub_efi_compare_device_paths (dp, cdp) != 0)
       {
 	grub_efi_device_path_t *ldp, *dup_dp, *dup_ldp;
 	int match;

 	/* EDK2 UEFI PXE driver creates pseudo devices with type IPv4/IPv6
 	   as children of Ethernet card and binds PXE and Load File protocols
 	   to it. Loaded Image Device Path protocol will point to these pseudo
 	   devices. We skip them when enumerating cards, so here we need to
 	   find matching MAC device.
          */
 	ldp = grub_efi_find_last_device_path (dp);
 	if (GRUB_EFI_DEVICE_PATH_TYPE (ldp) != GRUB_EFI_MESSAGING_DEVICE_PATH_TYPE
 	    || (GRUB_EFI_DEVICE_PATH_SUBTYPE (ldp) != GRUB_EFI_IPV4_DEVICE_PATH_SUBTYPE
 		&& GRUB_EFI_DEVICE_PATH_SUBTYPE (ldp) != GRUB_EFI_IPV6_DEVICE_PATH_SUBTYPE))
 	  continue;
 	dup_dp = grub_efi_duplicate_device_path (dp);
 	if (!dup_dp)
 	  continue;
 	dup_ldp = grub_efi_find_last_device_path (dup_dp);
 	dup_ldp->type = GRUB_EFI_END_DEVICE_PATH_TYPE;
 	dup_ldp->subtype = GRUB_EFI_END_ENTIRE_DEVICE_PATH_SUBTYPE;
 	dup_ldp->length = sizeof (*dup_ldp);
 	match = grub_efi_compare_device_paths (dup_dp, cdp) == 0;
 	grub_free (dup_dp);
 	if (!match)
 	  continue;
       }
     pxe = grub_efi_open_protocol (hnd, &pxe_io_guid,
 				  GRUB_EFI_OPEN_PROTOCOL_GET_PROTOCOL);
     if (! pxe)
       continue;
     pxe_mode = pxe->mode;
     grub_net_configure_by_dhcp_ack (card->name, card, 0,
 				    (struct grub_net_bootp_packet *)
 				    &pxe_mode->dhcp_ack,
 				    sizeof (pxe_mode->dhcp_ack),
 				    1, device, path);
     return;
   }
 }

 GRUB_MOD_INIT(efinet)
 {
   grub_efinet_findcards ();
   grub_efi_net_config = grub_efi_net_config_real;
 }

 GRUB_MOD_FINI(efinet)
 {
   struct grub_net_card *card, *next;

   FOR_NET_CARDS_SAFE (card, next)
     if (card->driver == &efidriver)
       grub_net_card_unregister (card);
 }
	/*
	* GRUB -- GRand Unified Bootloader
	* Copyright (C) 2010,2011 Free Software Foundation, Inc.
	*
	* GRUB 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 3 of the License, or
	* (at your option) any later version.
	*
	* GRUB 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 GRUB. If not, see <http://www.gnu.org/licenses/>.
	*/

	#include <grub/net/netbuff.h>
	#include <grub/dl.h>
	#include <grub/net.h>
	#include <grub/time.h>
	#include <grub/efi/api.h>
	#include <grub/efi/efi.h>
	#include <grub/i18n.h>

	GRUB_MOD_LICENSE ("GPLv3+");

	/* GUID. */
	static grub_efi_guid_t net_io_guid = GRUB_EFI_SIMPLE_NETWORK_GUID;
	static grub_efi_guid_t pxe_io_guid = GRUB_EFI_PXE_GUID;

	static grub_err_t
	send_card_buffer (struct grub_net_card *dev,
	struct grub_net_buff *pack)
	{
	grub_efi_status_t st;
	grub_efi_simple_network_t *net = dev->efi_net;
	grub_uint64_t limit_time = grub_get_time_ms () + 4000;
	void *txbuf;

	if (dev->txbusy)
	while (1)
	{
	txbuf = NULL;
	st = efi_call_3 (net->get_status, net, 0, &txbuf);
	if (st != GRUB_EFI_SUCCESS)
	return grub_error (GRUB_ERR_IO,
	N_("couldn't send network packet"));
	/*
	Some buggy firmware could return an arbitrary address instead of the
	txbuf address we trasmitted, so just check that txbuf is non NULL
	for success. This is ok because we open the SNP protocol in
	exclusive mode so we know we're the only ones transmitting on this
	box and since we only transmit one packet at a time we know our
	transmit was successfull.
	*/
	if (txbuf)
	{
	dev->txbusy = 0;
	break;
	}
	if (limit_time < grub_get_time_ms ())
	return grub_error (GRUB_ERR_TIMEOUT,
	N_("couldn't send network packet"));
	}

	dev->last_pkt_size = (pack->tail - pack->data);
	if (dev->last_pkt_size > dev->mtu)
	dev->last_pkt_size = dev->mtu;

	grub_memcpy (dev->txbuf, pack->data, dev->last_pkt_size);

	st = efi_call_7 (net->transmit, net, 0, dev->last_pkt_size,
	dev->txbuf, NULL, NULL, NULL);
	if (st != GRUB_EFI_SUCCESS)
	return grub_error (GRUB_ERR_IO, N_("couldn't send network packet"));

	/*
	The card may have sent out the packet immediately - set txbusy
	to 0 in this case.
	Cases were observed where checking txbuf at the next call
	of send_card_buffer() is too late: 0 is returned in txbuf and
	we run in the GRUB_ERR_TIMEOUT case above.
	Perhaps a timeout in the FW has discarded the recycle buffer.
	*/
	txbuf = NULL;
	st = efi_call_3 (net->get_status, net, 0, &txbuf);
	dev->txbusy = !(st == GRUB_EFI_SUCCESS && txbuf);

	return GRUB_ERR_NONE;
	}

	static struct grub_net_buff *
	get_card_packet (struct grub_net_card *dev)
	{
	grub_efi_simple_network_t *net = dev->efi_net;
	grub_err_t err;
	grub_efi_status_t st;
	grub_efi_uintn_t bufsize = dev->rcvbufsize;
	struct grub_net_buff *nb;
	int i;

	for (i = 0; i < 2; i++)
	{
	if (!dev->rcvbuf)
	dev->rcvbuf = grub_malloc (dev->rcvbufsize);
	if (!dev->rcvbuf)
	return NULL;

	st = efi_call_7 (net->receive, net, NULL, &bufsize,
	dev->rcvbuf, NULL, NULL, NULL);
	if (st != GRUB_EFI_BUFFER_TOO_SMALL)
	break;
	dev->rcvbufsize = 2 * ALIGN_UP (dev->rcvbufsize > bufsize
	? dev->rcvbufsize : bufsize, 64);
	grub_free (dev->rcvbuf);
	dev->rcvbuf = 0;
	}

	if (st != GRUB_EFI_SUCCESS)
	return NULL;

	nb = grub_netbuff_alloc (bufsize + 2);
	if (!nb)
	return NULL;

	/* Reserve 2 bytes so that 2 + 14/18 bytes of ethernet header is divisible
	by 4. So that IP header is aligned on 4 bytes. */
	if (grub_netbuff_reserve (nb, 2))
	{
	grub_netbuff_free (nb);
	return NULL;
	}
	grub_memcpy (nb->data, dev->rcvbuf, bufsize);
	err = grub_netbuff_put (nb, bufsize);
	if (err)
	{
	grub_netbuff_free (nb);
	return NULL;
	}

	return nb;
	}

	static grub_err_t
	open_card (struct grub_net_card *dev)
	{
	grub_efi_simple_network_t *net;

	/* Try to reopen SNP exlusively to close any active MNP protocol instance
	that may compete for packet polling
	*/
	net = grub_efi_open_protocol (dev->efi_handle, &net_io_guid,
	GRUB_EFI_OPEN_PROTOCOL_BY_EXCLUSIVE);
	if (net)
	{
	if (net->mode->state == GRUB_EFI_NETWORK_STOPPED
	&& efi_call_1 (net->start, net) != GRUB_EFI_SUCCESS)
	return grub_error (GRUB_ERR_NET_NO_CARD, "%s: net start failed",
	dev->name);

	if (net->mode->state == GRUB_EFI_NETWORK_STOPPED)
	return grub_error (GRUB_ERR_NET_NO_CARD, "%s: card stopped",
	dev->name);

	if (net->mode->state == GRUB_EFI_NETWORK_STARTED
	&& efi_call_3 (net->initialize, net, 0, 0) != GRUB_EFI_SUCCESS)
	return grub_error (GRUB_ERR_NET_NO_CARD, "%s: net initialize failed",
	dev->name);

	/* Enable hardware receive filters if driver declares support for it.
	We need unicast and broadcast and additionaly all nodes and
	solicited multicast for IPv6. Solicited multicast is per-IPv6
	address and we currently do not have API to do it so simply
	try to enable receive of all multicast packets or evertyhing in
	the worst case (i386 PXE driver always enables promiscuous too).

	This does trust firmware to do what it claims to do.
	*/
	if (net->mode->receive_filter_mask)
	{
	grub_uint32_t filters = GRUB_EFI_SIMPLE_NETWORK_RECEIVE_UNICAST \|
	GRUB_EFI_SIMPLE_NETWORK_RECEIVE_BROADCAST \|
	GRUB_EFI_SIMPLE_NETWORK_RECEIVE_PROMISCUOUS_MULTICAST;

	filters &= net->mode->receive_filter_mask;
	if (!(filters & GRUB_EFI_SIMPLE_NETWORK_RECEIVE_PROMISCUOUS_MULTICAST))
	filters \|= (net->mode->receive_filter_mask &
	GRUB_EFI_SIMPLE_NETWORK_RECEIVE_PROMISCUOUS);

	efi_call_6 (net->receive_filters, net, filters, 0, 0, 0, NULL);
	}

	efi_call_4 (grub_efi_system_table->boot_services->close_protocol,
	dev->efi_net, &net_io_guid,
	grub_efi_image_handle, dev->efi_handle);
	dev->efi_net = net;
	}

	/* If it failed we just try to run as best as we can */
	return GRUB_ERR_NONE;
	}

	static void
	close_card (struct grub_net_card *dev)
	{
	efi_call_1 (dev->efi_net->shutdown, dev->efi_net);
	efi_call_1 (dev->efi_net->stop, dev->efi_net);
	efi_call_4 (grub_efi_system_table->boot_services->close_protocol,
	dev->efi_net, &net_io_guid,
	grub_efi_image_handle, dev->efi_handle);
	}

	static struct grub_net_card_driver efidriver =
	{
	.name = "efinet",
	.open = open_card,
	.close = close_card,
	.send = send_card_buffer,
	.recv = get_card_packet
	};

	grub_efi_handle_t
	grub_efinet_get_device_handle (struct grub_net_card *card)
	{
	if (!card \|\| card->driver != &efidriver)
	return 0;
	return card->efi_handle;
	}

	static void
	grub_efinet_findcards (void)
	{
	grub_efi_uintn_t num_handles;
	grub_efi_handle_t *handles;
	grub_efi_handle_t *handle;
	int i = 0;

	/* Find handles which support the disk io interface. */
	handles = grub_efi_locate_handle (GRUB_EFI_BY_PROTOCOL, &net_io_guid,
	0, &num_handles);
	if (! handles)
	return;
	for (handle = handles; num_handles--; handle++)
	{
	grub_efi_simple_network_t *net;
	struct grub_net_card *card;
	grub_efi_device_path_t dp, parent = NULL, *child = NULL;

	/* EDK2 UEFI PXE driver creates IPv4 and IPv6 messaging devices as
	children of main MAC messaging device. We only need one device with
	bound SNP per physical card, otherwise they compete with each other
	when polling for incoming packets.
	*/
	dp = grub_efi_get_device_path (*handle);
	if (!dp)
	continue;
	for (; ! GRUB_EFI_END_ENTIRE_DEVICE_PATH (dp); dp = GRUB_EFI_NEXT_DEVICE_PATH (dp))
	{
	parent = child;
	child = dp;
	}
	if (child
	&& GRUB_EFI_DEVICE_PATH_TYPE (child) == GRUB_EFI_MESSAGING_DEVICE_PATH_TYPE
	&& (GRUB_EFI_DEVICE_PATH_SUBTYPE (child) == GRUB_EFI_IPV4_DEVICE_PATH_SUBTYPE
	\|\| GRUB_EFI_DEVICE_PATH_SUBTYPE (child) == GRUB_EFI_IPV6_DEVICE_PATH_SUBTYPE)
	&& parent
	&& GRUB_EFI_DEVICE_PATH_TYPE (parent) == GRUB_EFI_MESSAGING_DEVICE_PATH_TYPE
	&& GRUB_EFI_DEVICE_PATH_SUBTYPE (parent) == GRUB_EFI_MAC_ADDRESS_DEVICE_PATH_SUBTYPE)
	continue;

	net = grub_efi_open_protocol (*handle, &net_io_guid,
	GRUB_EFI_OPEN_PROTOCOL_GET_PROTOCOL);
	if (! net)
	/* This should not happen... Why? */
	continue;

	if (net->mode->state == GRUB_EFI_NETWORK_STOPPED
	&& efi_call_1 (net->start, net) != GRUB_EFI_SUCCESS)
	continue;

	if (net->mode->state == GRUB_EFI_NETWORK_STOPPED)
	continue;

	if (net->mode->state == GRUB_EFI_NETWORK_STARTED
	&& efi_call_3 (net->initialize, net, 0, 0) != GRUB_EFI_SUCCESS)
	continue;

	card = grub_zalloc (sizeof (struct grub_net_card));
	if (!card)
	{
	grub_print_error ();
	grub_free (handles);
	return;
	}

	card->mtu = net->mode->max_packet_size;
	card->txbufsize = ALIGN_UP (card->mtu, 64) + 256;
	card->txbuf = grub_zalloc (card->txbufsize);
	if (!card->txbuf)
	{
	grub_print_error ();
	grub_free (handles);
	grub_free (card);
	return;
	}
	card->txbusy = 0;

	card->rcvbufsize = ALIGN_UP (card->mtu, 64) + 256;

	card->name = grub_xasprintf ("efinet%d", i++);
	card->driver = &efidriver;
	card->flags = 0;
	card->default_address.type = GRUB_NET_LINK_LEVEL_PROTOCOL_ETHERNET;
	grub_memcpy (card->default_address.mac,
	net->mode->current_address,
	sizeof (card->default_address.mac));
	card->efi_net = net;
	card->efi_handle = *handle;

	grub_net_card_register (card);
	}
	grub_free (handles);
	}

	static void
	grub_efi_net_config_real (grub_efi_handle_t hnd, char **device,
	char **path)
	{
	struct grub_net_card *card;
	grub_efi_device_path_t *dp;

	dp = grub_efi_get_device_path (hnd);
	if (! dp)
	return;

	FOR_NET_CARDS (card)
	{
	grub_efi_device_path_t *cdp;
	struct grub_efi_pxe *pxe;
	struct grub_efi_pxe_mode *pxe_mode;
	if (card->driver != &efidriver)
	continue;
	cdp = grub_efi_get_device_path (card->efi_handle);
	if (! cdp)
	continue;
	if (grub_efi_compare_device_paths (dp, cdp) != 0)
	{
	grub_efi_device_path_t ldp, dup_dp, *dup_ldp;
	int match;

	/* EDK2 UEFI PXE driver creates pseudo devices with type IPv4/IPv6
	as children of Ethernet card and binds PXE and Load File protocols
	to it. Loaded Image Device Path protocol will point to these pseudo
	devices. We skip them when enumerating cards, so here we need to
	find matching MAC device.
	*/
	ldp = grub_efi_find_last_device_path (dp);
	if (GRUB_EFI_DEVICE_PATH_TYPE (ldp) != GRUB_EFI_MESSAGING_DEVICE_PATH_TYPE
	\|\| (GRUB_EFI_DEVICE_PATH_SUBTYPE (ldp) != GRUB_EFI_IPV4_DEVICE_PATH_SUBTYPE
	&& GRUB_EFI_DEVICE_PATH_SUBTYPE (ldp) != GRUB_EFI_IPV6_DEVICE_PATH_SUBTYPE))
	continue;
	dup_dp = grub_efi_duplicate_device_path (dp);
	if (!dup_dp)
	continue;
	dup_ldp = grub_efi_find_last_device_path (dup_dp);
	dup_ldp->type = GRUB_EFI_END_DEVICE_PATH_TYPE;
	dup_ldp->subtype = GRUB_EFI_END_ENTIRE_DEVICE_PATH_SUBTYPE;
	dup_ldp->length = sizeof (*dup_ldp);
	match = grub_efi_compare_device_paths (dup_dp, cdp) == 0;
	grub_free (dup_dp);
	if (!match)
	continue;
	}
	pxe = grub_efi_open_protocol (hnd, &pxe_io_guid,
	GRUB_EFI_OPEN_PROTOCOL_GET_PROTOCOL);
	if (! pxe)
	continue;
	pxe_mode = pxe->mode;
	grub_net_configure_by_dhcp_ack (card->name, card, 0,
	(struct grub_net_bootp_packet *)
	&pxe_mode->dhcp_ack,
	sizeof (pxe_mode->dhcp_ack),
	1, device, path);
	return;
	}
	}

	GRUB_MOD_INIT(efinet)
	{
	grub_efinet_findcards ();
	grub_efi_net_config = grub_efi_net_config_real;
	}

	GRUB_MOD_FINI(efinet)
	{
	struct grub_net_card card, next;

	FOR_NET_CARDS_SAFE (card, next)
	if (card->driver == &efidriver)
	grub_net_card_unregister (card);
	}