grub/grub-core/net/net.c

/*
 *  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.h>
#include <grub/net/netbuff.h>
#include <grub/time.h>
#include <grub/file.h>
#include <grub/i18n.h>
#include <grub/mm.h>
#include <grub/misc.h>
#include <grub/dl.h>
#include <grub/command.h>
#include <grub/env.h>
#include <grub/net/ethernet.h>
#include <grub/loader.h>
#include <grub/bufio.h>
#include <grub/kernel.h>

GRUB_MOD_LICENSE ("GPLv3+");

char *grub_net_default_server;

struct grub_net_route
{
  struct grub_net_route *next;
  grub_net_network_level_netaddress_t target;
  char *name;
  struct grub_net_network_level_protocol *prot;
  int is_gateway;
  union
  {
    struct grub_net_network_level_interface *interface;
    grub_net_network_level_address_t gw;
  };
};

struct grub_net_route *grub_net_routes = NULL;
struct grub_net_network_level_interface *grub_net_network_level_interfaces = NULL;
struct grub_net_card *grub_net_cards = NULL;
struct grub_net_network_level_protocol *grub_net_network_level_protocols = NULL;
static struct grub_fs grub_net_fs;

void
grub_net_card_unregister (struct grub_net_card *card)
{
  struct grub_net_network_level_interface *inf, *next;
  FOR_NET_NETWORK_LEVEL_INTERFACES_SAFE(inf, next)
    if (inf->card == card)
      grub_net_network_level_interface_unregister (inf);
  if (card->opened)
    {
      if (card->driver->close)
	card->driver->close (card);
      card->opened = 0;
    }
  grub_list_remove (GRUB_AS_LIST_P (&grub_net_cards),
		    GRUB_AS_LIST (card));
}


static inline void
grub_net_route_register (struct grub_net_route *route)
{
  grub_list_push (GRUB_AS_LIST_P (&grub_net_routes),
		  GRUB_AS_LIST (route));
}

static inline void
grub_net_route_unregister (struct grub_net_route *route)
{
  grub_list_remove (GRUB_AS_LIST_P (&grub_net_routes),
		    GRUB_AS_LIST (route));
}

#define FOR_NET_ROUTES(var) for (var = grub_net_routes; var; var = var->next)

static int
parse_ip (const char *val, grub_uint32_t *ip, const char **rest)
{
  grub_uint32_t newip = 0;
  unsigned long t;
  int i;
  const char *ptr = val;

  for (i = 0; i < 4; i++)
    {
      t = grub_strtoul (ptr, (char **) &ptr, 0);
      if (grub_errno)
	{
	  grub_errno = GRUB_ERR_NONE;
	  return 0;
	}
      if (t & ~0xff)
	return 0;
      newip >>= 8;
      newip |= (t << 24);
      if (i != 3 && *ptr != '.')
	return 0;
      ptr++;
    }
  *ip = grub_cpu_to_le32 (newip);
  if (rest)
    *rest = ptr - 1;
  return 1;
}

static int
match_net (const grub_net_network_level_netaddress_t *net,
	   const grub_net_network_level_address_t *addr)
{
  if (net->type != addr->type)
    return 0;
  switch (net->type)
    {
    case GRUB_NET_NETWORK_LEVEL_PROTOCOL_DHCP_RECV:
      return 0;
    case GRUB_NET_NETWORK_LEVEL_PROTOCOL_IPV4:
      {
	grub_int32_t mask = ((1 << net->ipv4.masksize) - 1) << (32 - net->ipv4.masksize);
	return ((grub_be_to_cpu32 (net->ipv4.base) & mask)
		== (grub_be_to_cpu32 (addr->ipv4) & mask));
      }
    }
  return 0;
}

grub_err_t
grub_net_resolve_address (const char *name,
			  grub_net_network_level_address_t *addr)
{
  if (parse_ip (name, &addr->ipv4, NULL))
    {
      addr->type = GRUB_NET_NETWORK_LEVEL_PROTOCOL_IPV4;
      return GRUB_ERR_NONE;
    }
  return grub_error (GRUB_ERR_NET_BAD_ADDRESS, N_("unrecognised address %s"),
		     name);
}

grub_err_t
grub_net_resolve_net_address (const char *name,
			      grub_net_network_level_netaddress_t *addr)
{
  const char *rest;
  if (parse_ip (name, &addr->ipv4.base, &rest))
    {
      addr->type = GRUB_NET_NETWORK_LEVEL_PROTOCOL_IPV4;
      if (*rest == '/')
	{
	  addr->ipv4.masksize = grub_strtoul (rest + 1, NULL, 0);
	  if (!grub_errno)
	    return GRUB_ERR_NONE;	    
	}
      addr->ipv4.masksize = 32;
      return GRUB_ERR_NONE;
    }
  return grub_error (GRUB_ERR_NET_BAD_ADDRESS, N_("unrecognised address %s"),
		     name);
}

grub_err_t
grub_net_route_address (grub_net_network_level_address_t addr,
			grub_net_network_level_address_t *gateway,
			struct grub_net_network_level_interface **interf)
{
  struct grub_net_route *route;
  int depth = 0;
  int routecnt = 0;
  struct grub_net_network_level_protocol *prot = NULL;
  grub_net_network_level_address_t curtarget = addr;

  *gateway = addr;

  FOR_NET_ROUTES(route)
    routecnt++;

  for (depth = 0; depth < routecnt + 2; depth++)
    {
      FOR_NET_ROUTES(route)
      {
	if (depth && prot != route->prot)
	  continue;
	if (!match_net (&route->target, &curtarget))
	  continue;

	if (route->is_gateway)
	  {
	    if (depth == 0)
	      *gateway = route->gw;
	    curtarget = route->gw;
	    break;
	  }
	*interf = route->interface;
	return GRUB_ERR_NONE;
      }
      if (route == NULL)
	return grub_error (GRUB_ERR_NET_NO_ROUTE, "destination unreachable");
    }

  return grub_error (GRUB_ERR_NET_ROUTE_LOOP, "route loop detected");
}

static grub_err_t
grub_cmd_deladdr (struct grub_command *cmd __attribute__ ((unused)),
		  int argc, char **args)
{
  struct grub_net_network_level_interface *inter;

  if (argc != 1)
    return grub_error (GRUB_ERR_BAD_ARGUMENT, N_("one argument expected"));

  FOR_NET_NETWORK_LEVEL_INTERFACES (inter)
    if (grub_strcmp (inter->name, args[1]) == 0)
      break;
  if (inter == NULL)
    return grub_error (GRUB_ERR_BAD_ARGUMENT, N_("address not found"));

  if (inter->flags & GRUB_NET_INTERFACE_PERMANENT)
    return grub_error (GRUB_ERR_IO,
		       N_("you can't delete this address"));

  grub_net_network_level_interface_unregister (inter);
  grub_free (inter->name);
  grub_free (inter);

  return GRUB_ERR_NONE;  
}

void
grub_net_addr_to_str (const grub_net_network_level_address_t *target, char *buf)
{
  switch (target->type)
    {
    case GRUB_NET_NETWORK_LEVEL_PROTOCOL_DHCP_RECV:
      grub_strcpy (buf, "temporary");
      return;
    case GRUB_NET_NETWORK_LEVEL_PROTOCOL_IPV4:
      {
	grub_uint32_t n = grub_be_to_cpu32 (target->ipv4);
	grub_snprintf (buf, GRUB_NET_MAX_STR_ADDR_LEN, "%d.%d.%d.%d",
		       ((n >> 24) & 0xff), ((n >> 16) & 0xff),
		       ((n >> 8) & 0xff), ((n >> 0) & 0xff));
      }
      return;
    }
  grub_printf ("Unknown address type %d\n", target->type);
}

/*
  Currently suppoerted adresses:
  ethernet:   XX:XX:XX:XX:XX:XX
 */

#define MAX_STR_HWADDR_LEN (sizeof ("XX:XX:XX:XX:XX:XX"))

static void
hwaddr_to_str (const grub_net_link_level_address_t *addr, char *str)
{
  str[0] = 0;
  switch (addr->type)
    {
    case GRUB_NET_LINK_LEVEL_PROTOCOL_ETHERNET:
      {
	char *ptr;
	unsigned i;
	for (ptr = str, i = 0; i < ARRAY_SIZE (addr->mac); i++)
	  {
	    grub_snprintf (ptr, MAX_STR_HWADDR_LEN - (ptr - str),
			   "%02x:", addr->mac[i] & 0xff);
	    ptr += (sizeof ("XX:") - 1);
	  }
      return;
      }
    }
  grub_printf ("Unsupported hw address type %d\n", addr->type);
}

int
grub_net_hwaddr_cmp (const grub_net_link_level_address_t *a,
		     const grub_net_link_level_address_t *b)
{
  if (a->type < b->type)
    return -1;
  if (a->type > b->type)
    return +1;
  switch (a->type)
    {
    case GRUB_NET_LINK_LEVEL_PROTOCOL_ETHERNET:
      return grub_memcmp (a->mac, b->mac, sizeof (a->mac));
    }
  grub_printf ("Unsupported hw address type %d\n", a->type);
  return 1;
}

/* FIXME: implement this. */
static char *
hwaddr_set_env (struct grub_env_var *var __attribute__ ((unused)),
		const char *val __attribute__ ((unused)))
{
  return NULL;
}

/* FIXME: implement this. */
static char *
addr_set_env (struct grub_env_var *var __attribute__ ((unused)),
	      const char *val __attribute__ ((unused)))
{
  return NULL;
}

static void
grub_net_network_level_interface_register (struct grub_net_network_level_interface *inter)
{
  {
    char buf[MAX_STR_HWADDR_LEN];
    char name[grub_strlen (inter->name) + sizeof ("net__mac")];
    hwaddr_to_str (&inter->hwaddress, buf);
    grub_snprintf (name, sizeof (name), "net_%s_mac", inter->name);
    grub_env_set (name, buf);
    grub_register_variable_hook (name, 0, hwaddr_set_env);
  }

  {
    char buf[GRUB_NET_MAX_STR_ADDR_LEN];
    char name[grub_strlen (inter->name) + sizeof ("net__ip")];
    grub_net_addr_to_str (&inter->address, buf);
    grub_snprintf (name, sizeof (name), "net_%s_ip", inter->name);
    grub_env_set (name, buf);
    grub_register_variable_hook (name, 0, addr_set_env);
  }

  inter->card->num_ifaces++;
  inter->prev = &grub_net_network_level_interfaces;
  inter->next = grub_net_network_level_interfaces;
  if (inter->next)
    inter->next->prev = &inter->next;
  grub_net_network_level_interfaces = inter;
}

struct grub_net_network_level_interface *
grub_net_add_addr (const char *name, 
		   struct grub_net_card *card,
		   grub_net_network_level_address_t addr,
		   grub_net_link_level_address_t hwaddress,
		   grub_net_interface_flags_t flags)
{
  struct grub_net_network_level_interface *inter;

  inter = grub_zalloc (sizeof (*inter));
  if (!inter)
    return NULL;

  inter->name = grub_strdup (name);
  grub_memcpy (&(inter->address), &addr, sizeof (inter->address));
  grub_memcpy (&(inter->hwaddress), &hwaddress, sizeof (inter->hwaddress));
  inter->flags = flags;
  inter->card = card;
  inter->dhcp_ack = NULL;
  inter->dhcp_acklen = 0;

  grub_net_network_level_interface_register (inter);

  return inter;
}

/* FIXME: support MAC specifying.  */
static grub_err_t
grub_cmd_addaddr (struct grub_command *cmd __attribute__ ((unused)),
		  int argc, char **args)
{
  struct grub_net_card *card;
  grub_net_network_level_address_t addr;
  grub_err_t err;
  grub_net_interface_flags_t flags = 0;

  if (argc != 3)
    return grub_error (GRUB_ERR_BAD_ARGUMENT, N_("three arguments expected"));
  
  FOR_NET_CARDS (card)
    if (grub_strcmp (card->name, args[1]) == 0)
      break;
  if (card == NULL)
    return grub_error (GRUB_ERR_BAD_ARGUMENT, N_("card not found")); 

  err = grub_net_resolve_address (args[2], &addr);
  if (err)
    return err;

  if (card->flags & GRUB_NET_CARD_NO_MANUAL_INTERFACES)
    return grub_error (GRUB_ERR_IO,
		       "this card doesn't support address addition");

  if (card->flags & GRUB_NET_CARD_HWADDRESS_IMMUTABLE)
    flags |= GRUB_NET_INTERFACE_HWADDRESS_IMMUTABLE;

  grub_net_add_addr (args[0], card, addr, card->default_address,
		     flags);
  return grub_errno;
}

static grub_err_t
grub_cmd_delroute (struct grub_command *cmd __attribute__ ((unused)),
		   int argc, char **args)
{
  struct grub_net_route *route;
  struct grub_net_route **prev;

  if (argc != 1)
    return grub_error (GRUB_ERR_BAD_ARGUMENT, N_("one argument expected"));
  
  for (prev = &grub_net_routes, route = *prev; route; prev = &((*prev)->next),
	 route = *prev)
    if (grub_strcmp (route->name, args[0]) == 0)
      {
	*prev = route->next;
	grub_free (route->name);
	grub_free (route);
      }

  return GRUB_ERR_NONE;
}

grub_err_t
grub_net_add_route (const char *name,
		    grub_net_network_level_netaddress_t target,
		    struct grub_net_network_level_interface *inter)
{
  struct grub_net_route *route;

  route = grub_zalloc (sizeof (*route));
  if (!route)
    return grub_errno;

  route->name = grub_strdup (name);
  if (!route->name)
    {
      grub_free (route);
      return grub_errno;
    }

  route->target = target;
  route->is_gateway = 0;
  route->interface = inter;

  grub_net_route_register (route);

  return GRUB_ERR_NONE;
}

grub_err_t
grub_net_add_route_gw (const char *name,
		       grub_net_network_level_netaddress_t target,
		       grub_net_network_level_address_t gw)
{
  struct grub_net_route *route;

  route = grub_zalloc (sizeof (*route));
  if (!route)
    return grub_errno;

  route->name = grub_strdup (name);
  if (!route->name)
    {
      grub_free (route);
      return grub_errno;
    }

  route->target = target;
  route->is_gateway = 1;
  route->gw = gw;

  grub_net_route_register (route);

  return GRUB_ERR_NONE;
}

static grub_err_t
grub_cmd_addroute (struct grub_command *cmd __attribute__ ((unused)),
		  int argc, char **args)
{
  grub_net_network_level_netaddress_t target;
  if (argc < 3)
    return grub_error (GRUB_ERR_BAD_ARGUMENT,
		       N_("At least 3 arguments are expected"));

  grub_net_resolve_net_address  (args[1], &target);
  
  if (grub_strcmp (args[2], "gw") == 0 && argc >= 4)
    {
      grub_err_t err;
      grub_net_network_level_address_t gw;

      err = grub_net_resolve_address (args[3], &gw);
      if (err)
	return err;
      return grub_net_add_route_gw (args[0], target, gw);
    }
  else
    {
      struct grub_net_network_level_interface *inter;

      FOR_NET_NETWORK_LEVEL_INTERFACES (inter)
	if (grub_strcmp (inter->name, args[2]) == 0)
	  break;

      if (!inter)
	return grub_error (GRUB_ERR_BAD_ARGUMENT,
			   N_("unrecognised interface %s"), args[2]);
      return grub_net_add_route (args[0], target, inter);
    }
}

static void
print_net_address (const grub_net_network_level_netaddress_t *target)
{
  switch (target->type)
    {
    case GRUB_NET_NETWORK_LEVEL_PROTOCOL_DHCP_RECV:
      grub_printf ("temporary\n");
      break;
    case GRUB_NET_NETWORK_LEVEL_PROTOCOL_IPV4:
      {
	grub_uint32_t n = grub_be_to_cpu32 (target->ipv4.base);
	grub_printf ("%d.%d.%d.%d/%d ", ((n >> 24) & 0xff),
		     ((n >> 16) & 0xff),
		     ((n >> 8) & 0xff),
		     ((n >> 0) & 0xff),
		     target->ipv4.masksize);
      }
      return;
    }
  grub_printf ("Unknown address type %d\n", target->type);
}

static void
print_address (const grub_net_network_level_address_t *target)
{
  char buf[GRUB_NET_MAX_STR_ADDR_LEN];
  grub_net_addr_to_str (target, buf);
  grub_xputs (buf);
}

static grub_err_t
grub_cmd_listroutes (struct grub_command *cmd __attribute__ ((unused)),
		     int argc __attribute__ ((unused)),
		     char **args __attribute__ ((unused)))
{
  struct grub_net_route *route;
  FOR_NET_ROUTES(route)
  {
    grub_printf ("%s ", route->name);
    print_net_address (&route->target);
    if (route->is_gateway)
      {
	grub_printf ("gw ");
	print_address (&route->gw);	
      }
    else
      grub_printf ("%s", route->interface->name);      
    grub_printf ("\n");
  }
  return GRUB_ERR_NONE;
}

static grub_err_t
grub_cmd_listcards (struct grub_command *cmd __attribute__ ((unused)),
		    int argc __attribute__ ((unused)),
		    char **args __attribute__ ((unused)))
{
  struct grub_net_card *card;
  FOR_NET_CARDS(card)
  {
    char buf[MAX_STR_HWADDR_LEN];
    hwaddr_to_str (&card->default_address, buf);
    grub_printf ("%s %s\n", card->name, buf);
  }
  return GRUB_ERR_NONE;
}

static grub_err_t
grub_cmd_listaddrs (struct grub_command *cmd __attribute__ ((unused)),
		    int argc __attribute__ ((unused)),
		    char **args __attribute__ ((unused)))
{
  struct grub_net_network_level_interface *inf;
  FOR_NET_NETWORK_LEVEL_INTERFACES (inf)
  {
    char bufh[MAX_STR_HWADDR_LEN];
    char bufn[GRUB_NET_MAX_STR_ADDR_LEN];
    hwaddr_to_str (&inf->hwaddress, bufh);
    grub_net_addr_to_str (&inf->address, bufn);
    grub_printf ("%s %s %s\n", inf->name, bufh, bufn);
  }
  return GRUB_ERR_NONE;
}

grub_net_app_level_t grub_net_app_level_list;
struct grub_net_socket *grub_net_sockets;

static grub_net_t
grub_net_open_real (const char *name)
{
  grub_net_app_level_t proto;
  const char *protname, *server;
  grub_size_t protnamelen;

  if (grub_strncmp (name, "pxe:", sizeof ("pxe:") - 1) == 0)
    {
      protname = "tftp";
      protnamelen = sizeof ("tftp") - 1;
      server = name + sizeof ("pxe:") - 1;
    }
  else if (grub_strcmp (name, "pxe") == 0)
    {
      protname = "tftp";
      protnamelen = sizeof ("tftp") - 1;
      server = grub_net_default_server;
    }
  else
    {
      const char *comma;
      comma = grub_strchr (name, ',');
      if (comma)
	{
	  protnamelen = comma - name;
	  server = comma + 1;
	  protname = name;
	}
      else
	{
	  protnamelen = grub_strlen (name);
	  server = grub_net_default_server;
	  protname = name;
	}
    }
  if (!server)
    {
      grub_error (GRUB_ERR_NET_BAD_ADDRESS, "no server");
      return NULL;
    }  

  FOR_NET_APP_LEVEL (proto)
  {
    if (grub_memcmp (proto->name, protname, protnamelen) == 0
	&& proto->name[protnamelen] == 0)
      {
	grub_net_t ret = grub_zalloc (sizeof (*ret));
	if (!ret)
	  return NULL;
	ret->protocol = proto;
	if (server)
	  {
	    ret->server = grub_strdup (server);
	    if (!ret->server)
	      {
		grub_free (ret);
		return NULL;
	      }
	  }
	else
	  ret->server = NULL;
	ret->fs = &grub_net_fs;
	ret->offset = 0;
	ret->eof = 0;
	return ret;
      }
  }
  grub_error (GRUB_ERR_UNKNOWN_DEVICE, "no such device");

  return NULL;
}

static grub_err_t
grub_net_fs_dir (grub_device_t device, const char *path __attribute__ ((unused)),
	       int (*hook) (const char *filename,
			    const struct grub_dirhook_info *info) __attribute__ ((unused)))
{
  if (!device->net)
    return grub_error (GRUB_ERR_BAD_FS, "invalid extent");
  return GRUB_ERR_NONE;
}

static grub_err_t
grub_net_fs_open (struct grub_file *file_out, const char *name)
{
  grub_err_t err;
  struct grub_file *file, *bufio;

  file = grub_malloc (sizeof (*file));
  if (!file)
    return grub_errno;

  grub_memcpy (file, file_out, sizeof (struct grub_file));
  file->device->net->packs.first = NULL;
  file->device->net->packs.last = NULL;
  file->device->net->name = grub_strdup (name);
  if (!file->device->net->name)
    return grub_errno;

  err = file->device->net->protocol->open (file, name);
  if (err)
    return err;
  bufio = grub_bufio_open (file, 32768);
  if (! bufio)
    {
      file->device->net->protocol->close (file);
      grub_free (file->device->net->name);
      grub_free (file);
      return grub_errno;
    }

  grub_memcpy (file_out, bufio, sizeof (struct grub_file));
  grub_free (bufio);
  return GRUB_ERR_NONE;
}

static grub_err_t
grub_net_fs_close (grub_file_t file)
{
  while (file->device->net->packs.first)
    {
      grub_netbuff_free (file->device->net->packs.first->nb);
      grub_net_remove_packet (file->device->net->packs.first);
    }
  file->device->net->protocol->close (file);
  grub_free (file->device->net->name);
  return GRUB_ERR_NONE;
}

static void
receive_packets (struct grub_net_card *card)
{
  if (card->num_ifaces == 0)
    return;
  if (!card->opened)
    {
      grub_err_t err = GRUB_ERR_NONE;
      if (card->driver->open)
	err = card->driver->open (card);
      if (err)
	{
	  grub_errno = GRUB_ERR_NONE;
	  return;
	}
      card->opened = 1;
    }
  while (1)
    {
      /* Maybe should be better have a fixed number of packets for each card
	 and just mark them as used and not used.  */ 
      struct grub_net_buff *nb;
      grub_ssize_t actual;
      nb = grub_netbuff_alloc (1500);
      if (!nb)
	{
	  grub_print_error ();
	  card->last_poll = grub_get_time_ms ();
	  return;
	}

      actual = card->driver->recv (card, nb);
      if (actual < 0)
	{
	  grub_netbuff_free (nb);
	  card->last_poll = grub_get_time_ms ();
	  break;
	}
      grub_net_recv_ethernet_packet (nb, card);
    }
  grub_print_error ();
}

void
grub_net_poll_cards (unsigned time)
{
  struct grub_net_card *card;
  grub_uint64_t start_time;
  FOR_NET_CARDS (card)
    {
      start_time = grub_get_time_ms ();
      while ((grub_get_time_ms () - start_time) < time)	
	receive_packets (card);
    }
}

static void
grub_net_poll_cards_idle_real (void)
{
  struct grub_net_card *card;
  FOR_NET_CARDS (card)
  {
    grub_uint64_t ctime = grub_get_time_ms ();

    if (ctime < card->last_poll
	|| ctime >= card->last_poll + card->idle_poll_delay_ms)
      receive_packets (card);
  }
}

/*  Read from the packets list*/
static grub_ssize_t
grub_net_fs_read_real (grub_file_t file, char *buf, grub_size_t len)
{
  grub_net_t sock = file->device->net;
  struct grub_net_buff *nb;
  char *ptr = buf;
  grub_size_t amount, total = 0;
  int try = 0;
  while (try <= 3)
    {
      while (sock->packs.first)
	{
	  try = 0;
	  nb = sock->packs.first->nb;
	  amount = nb->tail - nb->data;
	  if (amount > len)
	    amount = len;
	  len -= amount;
	  total += amount;
	  file->device->net->offset += amount;
	  if (buf)
	    {
	      grub_memcpy (ptr, nb->data, amount);
	      ptr += amount;
	    }
	  if (amount == (grub_size_t) (nb->tail - nb->data))
	    {
	      grub_netbuff_free (nb);
	      grub_net_remove_packet (sock->packs.first);
	    }
	  else
	    nb->data += amount;

	  if (!len)
	    return total;
	}
      if (!sock->eof)
	{
	  try++;
	  grub_net_poll_cards (200);
	}
      else
	return total;
    }
    return total;
}

static grub_err_t 
grub_net_seek_real (struct grub_file *file, grub_off_t offset)
{
  grub_size_t len = offset - file->device->net->offset;

  if (!len)
    return GRUB_ERR_NONE;

  if (file->device->net->offset > offset)
    {
      grub_err_t err;
      while (file->device->net->packs.first)
	{
	  grub_netbuff_free (file->device->net->packs.first->nb);
	  grub_net_remove_packet (file->device->net->packs.first);
	}
      file->device->net->protocol->close (file);

      file->device->net->packs.first = NULL;
      file->device->net->packs.last = NULL;
      file->device->net->offset = 0;
      file->device->net->eof = 0;
      err = file->device->net->protocol->open (file, file->device->net->name);
      if (err)
	return err;
      len = offset;
    }

  grub_net_fs_read_real (file, NULL, len);
  return GRUB_ERR_NONE;
}

static grub_ssize_t
grub_net_fs_read (grub_file_t file, char *buf, grub_size_t len)
{
  if (file->offset != file->device->net->offset)
    {
      grub_err_t err;
      err = grub_net_seek_real (file, file->offset);
      if (err)
	return err;
    }
  return grub_net_fs_read_real (file, buf, len);
}

static struct grub_fs grub_net_fs =
  {
    .name = "netfs",
    .dir = grub_net_fs_dir,
    .open = grub_net_fs_open,
    .read = grub_net_fs_read,
    .close = grub_net_fs_close,
    .label = NULL,
    .uuid = NULL,
    .mtime = NULL,
  };

static grub_err_t
grub_net_fini_hw (int noreturn __attribute__ ((unused)))
{
  struct grub_net_card *card;
  FOR_NET_CARDS (card) 
    if (card->opened)
      {
	if (card->driver->close)
	  card->driver->close (card);
	card->opened = 0;
      }
  return GRUB_ERR_NONE;
}

static grub_err_t
grub_net_restore_hw (void)
{
  return GRUB_ERR_NONE;
}

static struct grub_preboot *fini_hnd;

static grub_command_t cmd_addaddr, cmd_deladdr, cmd_addroute, cmd_delroute;
static grub_command_t cmd_lsroutes, cmd_lscards;
static grub_command_t cmd_lsaddr;

GRUB_MOD_INIT(net)
{
  cmd_addaddr = grub_register_command ("net_add_addr", grub_cmd_addaddr,
				       N_("SHORTNAME CARD ADDRESS [HWADDRESS]"),
				       N_("Add a network address."));
  cmd_deladdr = grub_register_command ("net_del_addr", grub_cmd_deladdr,
				       N_("SHORTNAME"),
				       N_("Delete a network address."));
  cmd_addroute = grub_register_command ("net_add_route", grub_cmd_addroute,
					N_("SHORTNAME NET [INTERFACE| gw GATEWAY]"),
					N_("Add a network route."));
  cmd_delroute = grub_register_command ("net_del_route", grub_cmd_delroute,
					N_("SHORTNAME"),
					N_("Delete a network route."));
  cmd_lsroutes = grub_register_command ("net_ls_routes", grub_cmd_listroutes,
					"", N_("list network routes"));
  cmd_lscards = grub_register_command ("net_ls_cards", grub_cmd_listcards,
				       "", N_("list network cards"));
  cmd_lsaddr = grub_register_command ("net_ls_addr", grub_cmd_listaddrs,
				       "", N_("list network addresses"));
  grub_bootp_init ();

  grub_fs_register (&grub_net_fs);
  grub_net_open = grub_net_open_real;
  fini_hnd = grub_loader_register_preboot_hook (grub_net_fini_hw,
						grub_net_restore_hw,
						GRUB_LOADER_PREBOOT_HOOK_PRIO_DISK);
  grub_net_poll_cards_idle = grub_net_poll_cards_idle_real;
}

GRUB_MOD_FINI(net)
{
  grub_bootp_fini ();
  grub_unregister_command (cmd_addaddr);
  grub_unregister_command (cmd_deladdr);
  grub_unregister_command (cmd_addroute);
  grub_unregister_command (cmd_delroute);
  grub_unregister_command (cmd_lsroutes);
  grub_unregister_command (cmd_lscards);
  grub_unregister_command (cmd_lsaddr);
  grub_fs_unregister (&grub_net_fs);
  grub_net_open = NULL;
  grub_net_fini_hw (0);
  grub_loader_unregister_preboot_hook (fini_hnd);
  grub_net_poll_cards_idle = grub_net_poll_cards_idle_real;
}