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grub/grub-core/net/bootp.c
Andrei Borzenkov 5bc41db756 net/dhcp: Add explicit net_dhcp command 
Mostly for cosmetic reasons, we add a "net_dhcp" command, which is (at the
moment) identical to the existing "net_bootp" command. Both actually trigger
a DHCP handshake now, and both should be able to deal with pure BOOTP servers.
We could think about dropping the DHCP options from the initial DISCOVER packet
when the user issues the net_bootp command, but it's unclear whether this is
really useful, as both protocols should be able to coexist.

Signed-off-by: Andre Przywara <andre.przywara@arm.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
2019-03-12 20:04:07 +01:00

889 lines
24 KiB
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/*
* 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/env.h>
#include <grub/i18n.h>
#include <grub/command.h>
#include <grub/net/ip.h>
#include <grub/net/netbuff.h>
#include <grub/net/udp.h>
#include <grub/datetime.h>
struct grub_dhcp_discover_options
{
grub_uint8_t magic[4];
struct
{
grub_uint8_t code;
grub_uint8_t len;
grub_uint8_t data;
} GRUB_PACKED message_type;
grub_uint8_t end;
} GRUB_PACKED;
struct grub_dhcp_request_options
{
grub_uint8_t magic[4];
struct
{
grub_uint8_t code;
grub_uint8_t len;
grub_uint8_t data;
} GRUB_PACKED message_type;
struct
{
grub_uint8_t type;
grub_uint8_t len;
grub_uint32_t data;
} GRUB_PACKED server_identifier;
struct
{
grub_uint8_t type;
grub_uint8_t len;
grub_uint32_t data;
} GRUB_PACKED requested_ip;
struct
{
grub_uint8_t type;
grub_uint8_t len;
grub_uint8_t data[7];
} GRUB_PACKED parameter_request;
grub_uint8_t end;
} GRUB_PACKED;
enum
{
GRUB_DHCP_OPT_OVERLOAD_FILE = 1,
GRUB_DHCP_OPT_OVERLOAD_SNAME = 2,
};
enum
{
GRUB_DHCP_MESSAGE_UNKNOWN,
GRUB_DHCP_MESSAGE_DISCOVER,
GRUB_DHCP_MESSAGE_OFFER,
GRUB_DHCP_MESSAGE_REQUEST,
GRUB_DHCP_MESSAGE_DECLINE,
GRUB_DHCP_MESSAGE_ACK,
GRUB_DHCP_MESSAGE_NAK,
GRUB_DHCP_MESSAGE_RELEASE,
GRUB_DHCP_MESSAGE_INFORM,
};
#define GRUB_BOOTP_MAX_OPTIONS_SIZE 64
/* Max timeout when waiting for BOOTP/DHCP reply */
#define GRUB_DHCP_MAX_PACKET_TIMEOUT 32
#define GRUB_BOOTP_MAX_OPTIONS_SIZE 64
/* Max timeout when waiting for BOOTP/DHCP reply */
#define GRUB_DHCP_MAX_PACKET_TIMEOUT 32
static const void *
find_dhcp_option (const struct grub_net_bootp_packet *bp, grub_size_t size,
grub_uint8_t opt_code, grub_uint8_t *opt_len)
{
const grub_uint8_t *ptr;
grub_uint8_t overload = 0;
int end = 0;
grub_size_t i;
if (opt_len)
*opt_len = 0;
/* Is the packet big enough to hold at least the magic cookie? */
if (size < sizeof (*bp) + sizeof (grub_uint32_t))
return NULL;
/*
* Pointer arithmetic to point behind the common stub packet, where
* the options start.
*/
ptr = (grub_uint8_t *) (bp + 1);
if (ptr[0] != GRUB_NET_BOOTP_RFC1048_MAGIC_0
|| ptr[1] != GRUB_NET_BOOTP_RFC1048_MAGIC_1
|| ptr[2] != GRUB_NET_BOOTP_RFC1048_MAGIC_2
|| ptr[3] != GRUB_NET_BOOTP_RFC1048_MAGIC_3)
return NULL;
size -= sizeof (*bp);
i = sizeof (grub_uint32_t);
again:
while (i < size)
{
grub_uint8_t tagtype;
grub_uint8_t taglength;
tagtype = ptr[i++];
/* Pad tag. */
if (tagtype == GRUB_NET_BOOTP_PAD)
continue;
/* End tag. */
if (tagtype == GRUB_NET_BOOTP_END)
{
end = 1;
break;
}
if (i >= size)
return NULL;
taglength = ptr[i++];
if (i + taglength >= size)
return NULL;
/* FIXME RFC 3396 options concatentation */
if (tagtype == opt_code)
{
if (opt_len)
*opt_len = taglength;
return &ptr[i];
}
if (tagtype == GRUB_NET_DHCP_OVERLOAD && taglength == 1)
overload = ptr[i];
i += taglength;
}
if (!end)
return NULL;
/* RFC2131, 4.1, 23ff:
* If the options in a DHCP message extend into the 'sname' and 'file'
* fields, the 'option overload' option MUST appear in the 'options'
* field, with value 1, 2 or 3, as specified in RFC 1533. If the
* 'option overload' option is present in the 'options' field, the
* options in the 'options' field MUST be terminated by an 'end' option,
* and MAY contain one or more 'pad' options to fill the options field.
* The options in the 'sname' and 'file' fields (if in use as indicated
* by the 'options overload' option) MUST begin with the first octet of
* the field, MUST be terminated by an 'end' option, and MUST be
* followed by 'pad' options to fill the remainder of the field. Any
* individual option in the 'options', 'sname' and 'file' fields MUST be
* entirely contained in that field. The options in the 'options' field
* MUST be interpreted first, so that any 'option overload' options may
* be interpreted. The 'file' field MUST be interpreted next (if the
* 'option overload' option indicates that the 'file' field contains
* DHCP options), followed by the 'sname' field.
*
* FIXME: We do not explicitly check for trailing 'pad' options here.
*/
end = 0;
if (overload & GRUB_DHCP_OPT_OVERLOAD_FILE)
{
overload &= ~GRUB_DHCP_OPT_OVERLOAD_FILE;
ptr = (grub_uint8_t *) &bp->boot_file[0];
size = sizeof (bp->boot_file);
i = 0;
goto again;
}
if (overload & GRUB_DHCP_OPT_OVERLOAD_SNAME)
{
overload &= ~GRUB_DHCP_OPT_OVERLOAD_SNAME;
ptr = (grub_uint8_t *) &bp->server_name[0];
size = sizeof (bp->server_name);
i = 0;
goto again;
}
return NULL;
}
#define OFFSET_OF(x, y) ((grub_size_t)((grub_uint8_t *)((y)->x) - (grub_uint8_t *)(y)))
struct grub_net_network_level_interface *
grub_net_configure_by_dhcp_ack (const char *name,
struct grub_net_card *card,
grub_net_interface_flags_t flags,
const struct grub_net_bootp_packet *bp,
grub_size_t size,
int is_def, char **device, char **path)
{
grub_net_network_level_address_t addr;
grub_net_link_level_address_t hwaddr;
struct grub_net_network_level_interface *inter;
int mask = -1;
char server_ip[sizeof ("xxx.xxx.xxx.xxx")];
const grub_uint8_t *opt;
grub_uint8_t opt_len, overload = 0;
const char *boot_file = 0, *server_name = 0;
grub_size_t boot_file_len, server_name_len;
addr.type = GRUB_NET_NETWORK_LEVEL_PROTOCOL_IPV4;
addr.ipv4 = bp->your_ip;
if (device)
*device = 0;
if (path)
*path = 0;
grub_memcpy (hwaddr.mac, bp->mac_addr,
bp->hw_len < sizeof (hwaddr.mac) ? bp->hw_len
: sizeof (hwaddr.mac));
hwaddr.type = GRUB_NET_LINK_LEVEL_PROTOCOL_ETHERNET;
inter = grub_net_add_addr (name, card, &addr, &hwaddr, flags);
if (!inter)
return 0;
opt = find_dhcp_option (bp, size, GRUB_NET_DHCP_OVERLOAD, &opt_len);
if (opt && opt_len == 1)
overload = *opt;
opt = find_dhcp_option (bp, size, GRUB_NET_DHCP_TFTP_SERVER_NAME, &opt_len);
if (opt && opt_len)
{
server_name = (const char *) opt;
server_name_len = opt_len;
}
else if (size > OFFSET_OF (server_name, bp) && !(overload & GRUB_DHCP_OPT_OVERLOAD_SNAME) &&
bp->server_name[0])
{
server_name = bp->server_name;
server_name_len = sizeof (bp->server_name);
}
opt = find_dhcp_option (bp, size, GRUB_NET_DHCP_BOOTFILE_NAME, &opt_len);
if (opt && opt_len)
{
boot_file = (const char *) opt;
boot_file_len = opt_len;
}
else if (size > OFFSET_OF (boot_file, bp) && !(overload && GRUB_DHCP_OPT_OVERLOAD_FILE) &&
bp->boot_file[0])
{
boot_file = bp->boot_file;
boot_file_len = sizeof (bp->boot_file);
}
if (bp->server_ip)
{
grub_snprintf (server_ip, sizeof (server_ip), "%d.%d.%d.%d",
((grub_uint8_t *) &bp->server_ip)[0],
((grub_uint8_t *) &bp->server_ip)[1],
((grub_uint8_t *) &bp->server_ip)[2],
((grub_uint8_t *) &bp->server_ip)[3]);
grub_env_set_net_property (name, "next_server", server_ip, sizeof (server_ip));
grub_print_error ();
}
if (is_def)
grub_net_default_server = 0;
if (is_def && !grub_net_default_server && bp->server_ip)
{
grub_net_default_server = grub_strdup (server_ip);
grub_print_error ();
}
if (is_def)
{
grub_env_set ("net_default_interface", name);
grub_env_export ("net_default_interface");
}
if (device && !*device && bp->server_ip)
{
*device = grub_xasprintf ("tftp,%s", server_ip);
grub_print_error ();
}
if (server_name)
{
grub_env_set_net_property (name, "dhcp_server_name", server_name, server_name_len);
if (is_def && !grub_net_default_server)
{
grub_net_default_server = grub_strdup (server_name);
grub_print_error ();
}
if (device && !*device)
{
*device = grub_xasprintf ("tftp,%s", server_name);
grub_print_error ();
}
}
if (boot_file)
{
grub_env_set_net_property (name, "boot_file", boot_file, boot_file_len);
if (path)
{
*path = grub_strndup (boot_file, boot_file_len);
grub_print_error ();
if (*path)
{
char *slash;
slash = grub_strrchr (*path, '/');
if (slash)
*slash = 0;
else
**path = 0;
}
}
}
opt = find_dhcp_option (bp, size, GRUB_NET_BOOTP_NETMASK, &opt_len);
if (opt && opt_len == 4)
{
int i;
for (i = 0; i < 32; i++)
if (!(opt[i / 8] & (1 << (7 - (i % 8)))))
break;
mask = i;
}
grub_net_add_ipv4_local (inter, mask);
/* We do not implement dead gateway detection and the first entry SHOULD
be preferred one */
opt = find_dhcp_option (bp, size, GRUB_NET_BOOTP_ROUTER, &opt_len);
if (opt && opt_len && !(opt_len & 3))
{
grub_net_network_level_netaddress_t target;
grub_net_network_level_address_t gw;
char *rname;
target.type = GRUB_NET_NETWORK_LEVEL_PROTOCOL_IPV4;
target.ipv4.base = 0;
target.ipv4.masksize = 0;
gw.type = GRUB_NET_NETWORK_LEVEL_PROTOCOL_IPV4;
gw.ipv4 = grub_get_unaligned32 (opt);
rname = grub_xasprintf ("%s:default", name);
if (rname)
grub_net_add_route_gw (rname, target, gw, 0);
grub_free (rname);
}
opt = find_dhcp_option (bp, size, GRUB_NET_BOOTP_DNS, &opt_len);
if (opt && opt_len && !(opt_len & 3))
{
int i;
for (i = 0; i < opt_len / 4; i++)
{
struct grub_net_network_level_address s;
s.type = GRUB_NET_NETWORK_LEVEL_PROTOCOL_IPV4;
s.ipv4 = grub_get_unaligned32 (opt);
s.option = DNS_OPTION_PREFER_IPV4;
grub_net_add_dns_server (&s);
opt += 4;
}
}
opt = find_dhcp_option (bp, size, GRUB_NET_BOOTP_HOSTNAME, &opt_len);
if (opt && opt_len)
grub_env_set_net_property (name, "hostname", (const char *) opt, opt_len);
opt = find_dhcp_option (bp, size, GRUB_NET_BOOTP_DOMAIN, &opt_len);
if (opt && opt_len)
grub_env_set_net_property (name, "domain", (const char *) opt, opt_len);
opt = find_dhcp_option (bp, size, GRUB_NET_BOOTP_ROOT_PATH, &opt_len);
if (opt && opt_len)
grub_env_set_net_property (name, "rootpath", (const char *) opt, opt_len);
opt = find_dhcp_option (bp, size, GRUB_NET_BOOTP_EXTENSIONS_PATH, &opt_len);
if (opt && opt_len)
grub_env_set_net_property (name, "extensionspath", (const char *) opt, opt_len);
inter->dhcp_ack = grub_malloc (size);
if (inter->dhcp_ack)
{
grub_memcpy (inter->dhcp_ack, bp, size);
inter->dhcp_acklen = size;
}
else
grub_errno = GRUB_ERR_NONE;
return inter;
}
static grub_err_t
send_dhcp_packet (struct grub_net_network_level_interface *iface)
{
grub_err_t err;
struct grub_net_bootp_packet *pack;
struct grub_datetime date;
grub_int32_t t = 0;
struct grub_net_buff *nb;
struct udphdr *udph;
grub_net_network_level_address_t target;
grub_net_link_level_address_t ll_target;
static struct grub_dhcp_discover_options discover_options =
{
{
GRUB_NET_BOOTP_RFC1048_MAGIC_0,
GRUB_NET_BOOTP_RFC1048_MAGIC_1,
GRUB_NET_BOOTP_RFC1048_MAGIC_2,
GRUB_NET_BOOTP_RFC1048_MAGIC_3,
},
{
GRUB_NET_DHCP_MESSAGE_TYPE,
sizeof (discover_options.message_type.data),
GRUB_DHCP_MESSAGE_DISCOVER,
},
GRUB_NET_BOOTP_END,
};
static struct grub_dhcp_request_options request_options =
{
{
GRUB_NET_BOOTP_RFC1048_MAGIC_0,
GRUB_NET_BOOTP_RFC1048_MAGIC_1,
GRUB_NET_BOOTP_RFC1048_MAGIC_2,
GRUB_NET_BOOTP_RFC1048_MAGIC_3,
},
{
GRUB_NET_DHCP_MESSAGE_TYPE,
sizeof (request_options.message_type.data),
GRUB_DHCP_MESSAGE_REQUEST,
},
{
GRUB_NET_DHCP_SERVER_IDENTIFIER,
sizeof (request_options.server_identifier.data),
0,
},
{
GRUB_NET_DHCP_REQUESTED_IP_ADDRESS,
sizeof (request_options.requested_ip.data),
0,
},
{
GRUB_NET_DHCP_PARAMETER_REQUEST_LIST,
sizeof (request_options.parameter_request.data),
{
GRUB_NET_BOOTP_NETMASK,
GRUB_NET_BOOTP_ROUTER,
GRUB_NET_BOOTP_DNS,
GRUB_NET_BOOTP_DOMAIN,
GRUB_NET_BOOTP_HOSTNAME,
GRUB_NET_BOOTP_ROOT_PATH,
GRUB_NET_BOOTP_EXTENSIONS_PATH,
},
},
GRUB_NET_BOOTP_END,
};
COMPILE_TIME_ASSERT (sizeof (discover_options) <= GRUB_BOOTP_MAX_OPTIONS_SIZE);
COMPILE_TIME_ASSERT (sizeof (request_options) <= GRUB_BOOTP_MAX_OPTIONS_SIZE);
nb = grub_netbuff_alloc (sizeof (*pack) + GRUB_BOOTP_MAX_OPTIONS_SIZE + 128);
if (!nb)
return grub_errno;
err = grub_netbuff_reserve (nb, sizeof (*pack) + GRUB_BOOTP_MAX_OPTIONS_SIZE + 128);
if (err)
goto out;
err = grub_netbuff_push (nb, GRUB_BOOTP_MAX_OPTIONS_SIZE);
if (err)
goto out;
grub_memset (nb->data, 0, GRUB_BOOTP_MAX_OPTIONS_SIZE);
if (!iface->srv_id)
{
grub_memcpy (nb->data, &discover_options, sizeof (discover_options));
}
else
{
struct grub_dhcp_request_options *ro = (struct grub_dhcp_request_options *) nb->data;
grub_memcpy (nb->data, &request_options, sizeof (request_options));
/* my_ip and srv_id are stored in network order so do not need conversion. */
grub_set_unaligned32 (&ro->server_identifier.data, iface->srv_id);
grub_set_unaligned32 (&ro->requested_ip.data, iface->my_ip);
}
err = grub_netbuff_push (nb, sizeof (*pack));
if (err)
goto out;
pack = (void *) nb->data;
grub_memset (pack, 0, sizeof (*pack));
pack->opcode = 1;
pack->hw_type = 1;
pack->hw_len = 6;
err = grub_get_datetime (&date);
if (err || !grub_datetime2unixtime (&date, &t))
{
grub_errno = GRUB_ERR_NONE;
t = 0;
}
pack->seconds = grub_cpu_to_be16 (t);
if (!iface->srv_id)
iface->xid = pack->ident = grub_cpu_to_be32 (t);
else
pack->ident = iface->xid;
grub_memcpy (&pack->mac_addr, &iface->hwaddress.mac, 6);
grub_netbuff_push (nb, sizeof (*udph));
udph = (struct udphdr *) nb->data;
udph->src = grub_cpu_to_be16_compile_time (68);
udph->dst = grub_cpu_to_be16_compile_time (67);
udph->chksum = 0;
udph->len = grub_cpu_to_be16 (nb->tail - nb->data);
target.type = GRUB_NET_NETWORK_LEVEL_PROTOCOL_IPV4;
target.ipv4 = 0xffffffff;
err = grub_net_link_layer_resolve (iface, &target, &ll_target);
if (err)
goto out;
udph->chksum = grub_net_ip_transport_checksum (nb, GRUB_NET_IP_UDP,
&iface->address,
&target);
err = grub_net_send_ip_packet (iface, &target, &ll_target, nb,
GRUB_NET_IP_UDP);
out:
grub_netbuff_free (nb);
return err;
}
/*
* This is called directly from net/ip.c:handle_dgram(), because those
* BOOTP/DHCP packets are a bit special due to their improper
* sender/receiver IP fields.
*/
void
grub_net_process_dhcp (struct grub_net_buff *nb,
struct grub_net_network_level_interface *iface)
{
char *name;
struct grub_net_card *card = iface->card;
const struct grub_net_bootp_packet *bp = (const struct grub_net_bootp_packet *) nb->data;
grub_size_t size = nb->tail - nb->data;
const grub_uint8_t *opt;
grub_uint8_t opt_len, type;
grub_uint32_t srv_id = 0;
opt = find_dhcp_option (bp, size, GRUB_NET_DHCP_MESSAGE_TYPE, &opt_len);
if (opt && opt_len == 1)
type = *opt;
else
type = GRUB_DHCP_MESSAGE_UNKNOWN;
opt = find_dhcp_option (bp, size, GRUB_NET_DHCP_SERVER_IDENTIFIER, &opt_len);
if (opt && opt_len == sizeof (srv_id))
srv_id = grub_get_unaligned32 (opt);
/*
* If we received BOOTP reply or DHCPACK, proceed with configuration.
* Otherwise store offered address and server id for later processing
* of DHCPACK.
* xid and srv_id are stored in network order so do not need conversion.
*/
if ((!iface->srv_id && type == GRUB_DHCP_MESSAGE_UNKNOWN)
|| (iface->srv_id && type == GRUB_DHCP_MESSAGE_ACK
&& bp->ident == iface->xid
&& srv_id == iface->srv_id))
{
name = grub_xasprintf ("%s:dhcp", card->name);
if (!name)
{
grub_print_error ();
return;
}
grub_net_configure_by_dhcp_ack (name, card, 0, bp, size, 0, 0, 0);
grub_free (name);
if (grub_errno)
grub_print_error ();
else
grub_net_network_level_interface_unregister (iface);
}
else if (!iface->srv_id && type == GRUB_DHCP_MESSAGE_OFFER && srv_id)
{
iface->srv_id = srv_id;
iface->my_ip = bp->your_ip;
/* Reset retransmission timer */
iface->dhcp_tmo = iface->dhcp_tmo_left = 1;
}
else if (iface->srv_id && type == GRUB_DHCP_MESSAGE_NAK
&& bp->ident == iface->xid
&& srv_id == iface->srv_id)
{
iface->xid = iface->srv_id = iface->my_ip = 0;
/* Reset retransmission timer */
iface->dhcp_tmo = iface->dhcp_tmo_left = 1;
}
}
static char
hexdigit (grub_uint8_t val)
{
if (val < 10)
return val + '0';
return val + 'a' - 10;
}
static grub_err_t
grub_cmd_dhcpopt (struct grub_command *cmd __attribute__ ((unused)),
int argc, char **args)
{
struct grub_net_network_level_interface *inter;
unsigned num;
const grub_uint8_t *ptr;
grub_uint8_t taglength;
if (argc < 4)
return grub_error (GRUB_ERR_BAD_ARGUMENT,
N_("four arguments expected"));
FOR_NET_NETWORK_LEVEL_INTERFACES (inter)
if (grub_strcmp (inter->name, args[1]) == 0)
break;
if (!inter)
return grub_error (GRUB_ERR_BAD_ARGUMENT,
N_("unrecognised network interface `%s'"), args[1]);
if (!inter->dhcp_ack)
return grub_error (GRUB_ERR_IO, N_("no DHCP info found"));
ptr = inter->dhcp_ack->vendor;
/* This duplicates check in find_dhcp_option to preserve previous error return */
if (inter->dhcp_acklen < OFFSET_OF (vendor, inter->dhcp_ack) + sizeof (grub_uint32_t)
|| ptr[0] != GRUB_NET_BOOTP_RFC1048_MAGIC_0
|| ptr[1] != GRUB_NET_BOOTP_RFC1048_MAGIC_1
|| ptr[2] != GRUB_NET_BOOTP_RFC1048_MAGIC_2
|| ptr[3] != GRUB_NET_BOOTP_RFC1048_MAGIC_3)
return grub_error (GRUB_ERR_IO, N_("no DHCP options found"));
num = grub_strtoul (args[2], 0, 0);
if (grub_errno)
return grub_errno;
/* Exclude PAD (0) and END (255) option codes */
if (num == 0 || num > 254)
return grub_error (GRUB_ERR_BAD_ARGUMENT, N_("invalid DHCP option code"));
ptr = find_dhcp_option (inter->dhcp_ack, inter->dhcp_acklen, num, &taglength);
if (!ptr)
return grub_error (GRUB_ERR_IO, N_("no DHCP option %u found"), num);
if (grub_strcmp (args[3], "string") == 0)
{
grub_err_t err = GRUB_ERR_NONE;
char *val = grub_malloc (taglength + 1);
if (!val)
return grub_errno;
grub_memcpy (val, ptr, taglength);
val[taglength] = 0;
if (args[0][0] == '-' && args[0][1] == 0)
grub_printf ("%s\n", val);
else
err = grub_env_set (args[0], val);
grub_free (val);
return err;
}
if (grub_strcmp (args[3], "number") == 0)
{
grub_uint64_t val = 0;
int i;
for (i = 0; i < taglength; i++)
val = (val << 8) | ptr[i];
if (args[0][0] == '-' && args[0][1] == 0)
grub_printf ("%llu\n", (unsigned long long) val);
else
{
char valn[64];
grub_snprintf (valn, sizeof (valn), "%lld\n", (unsigned long long) val);
return grub_env_set (args[0], valn);
}
return GRUB_ERR_NONE;
}
if (grub_strcmp (args[3], "hex") == 0)
{
grub_err_t err = GRUB_ERR_NONE;
char *val = grub_malloc (2 * taglength + 1);
int i;
if (!val)
return grub_errno;
for (i = 0; i < taglength; i++)
{
val[2 * i] = hexdigit (ptr[i] >> 4);
val[2 * i + 1] = hexdigit (ptr[i] & 0xf);
}
val[2 * taglength] = 0;
if (args[0][0] == '-' && args[0][1] == 0)
grub_printf ("%s\n", val);
else
err = grub_env_set (args[0], val);
grub_free (val);
return err;
}
return grub_error (GRUB_ERR_BAD_ARGUMENT,
N_("unrecognised DHCP option format specification `%s'"),
args[3]);
}
/* FIXME: allow to specify mac address. */
static grub_err_t
grub_cmd_bootp (struct grub_command *cmd __attribute__ ((unused)),
int argc, char **args)
{
struct grub_net_card *card;
struct grub_net_network_level_interface *ifaces;
grub_size_t ncards = 0;
unsigned j = 0;
grub_err_t err;
unsigned i;
FOR_NET_CARDS (card)
{
if (argc > 0 && grub_strcmp (card->name, args[0]) != 0)
continue;
ncards++;
}
if (ncards == 0)
return grub_error (GRUB_ERR_NET_NO_CARD, N_("no network card found"));
ifaces = grub_zalloc (ncards * sizeof (ifaces[0]));
if (!ifaces)
return grub_errno;
j = 0;
FOR_NET_CARDS (card)
{
if (argc > 0 && grub_strcmp (card->name, args[0]) != 0)
continue;
ifaces[j].card = card;
ifaces[j].next = &ifaces[j+1];
if (j)
ifaces[j].prev = &ifaces[j-1].next;
ifaces[j].name = grub_xasprintf ("%s:dhcp_tmp", card->name);
card->num_ifaces++;
if (!ifaces[j].name)
{
for (i = 0; i < j; i++)
grub_free (ifaces[i].name);
grub_free (ifaces);
return grub_errno;
}
ifaces[j].address.type = GRUB_NET_NETWORK_LEVEL_PROTOCOL_DHCP_RECV;
grub_memcpy (&ifaces[j].hwaddress, &card->default_address,
sizeof (ifaces[j].hwaddress));
ifaces[j].dhcp_tmo = ifaces[j].dhcp_tmo_left = 1;
j++;
}
ifaces[ncards - 1].next = grub_net_network_level_interfaces;
if (grub_net_network_level_interfaces)
grub_net_network_level_interfaces->prev = & ifaces[ncards - 1].next;
grub_net_network_level_interfaces = &ifaces[0];
ifaces[0].prev = &grub_net_network_level_interfaces;
/*
* Running DHCP restransmission timer is kept per interface in dhcp_tmo_left.
* When it runs off, dhcp_tmo is increased exponentionally and dhcp_tmo_left
* initialized to it. Max value is 32 which gives approximately 12s total per
* packet timeout assuming 200ms poll tick. Timeout is reset when DHCP OFFER
* is received, so total timeout is 25s in the worst case.
*
* DHCP NAK also resets timer and transaction starts again.
*
* Total wait time is limited to ~25s to prevent endless loop in case of
* permanent NAK
*/
for (i = 0; i < GRUB_DHCP_MAX_PACKET_TIMEOUT * 4; i++)
{
int need_poll = 0;
for (j = 0; j < ncards; j++)
{
if (!ifaces[j].prev ||
ifaces[j].dhcp_tmo > GRUB_DHCP_MAX_PACKET_TIMEOUT)
continue;
if (--ifaces[j].dhcp_tmo_left)
{
need_poll = 1;
continue;
}
ifaces[j].dhcp_tmo *= 2;
if (ifaces[j].dhcp_tmo > GRUB_DHCP_MAX_PACKET_TIMEOUT)
continue;
err = send_dhcp_packet (&ifaces[j]);
if (err)
{
grub_print_error ();
/* To ignore it during next poll */
ifaces[j].dhcp_tmo = GRUB_DHCP_MAX_PACKET_TIMEOUT + 1;
continue;
}
ifaces[j].dhcp_tmo_left = ifaces[j].dhcp_tmo;
need_poll = 1;
}
if (!need_poll)
break;
grub_net_poll_cards (200, 0);
}
err = GRUB_ERR_NONE;
for (j = 0; j < ncards; j++)
{
grub_free (ifaces[j].name);
if (!ifaces[j].prev)
continue;
grub_error_push ();
grub_net_network_level_interface_unregister (&ifaces[j]);
err = grub_error (GRUB_ERR_FILE_NOT_FOUND,
N_("couldn't autoconfigure %s"),
ifaces[j].card->name);
}
grub_free (ifaces);
return err;
}
static grub_command_t cmd_getdhcp, cmd_bootp, cmd_dhcp;
void
grub_bootp_init (void)
{
cmd_bootp = grub_register_command ("net_bootp", grub_cmd_bootp,
N_("[CARD]"),
N_("perform a bootp autoconfiguration"));
cmd_dhcp = grub_register_command ("net_dhcp", grub_cmd_bootp,
N_("[CARD]"),
N_("perform a DHCP autoconfiguration"));
cmd_getdhcp = grub_register_command ("net_get_dhcp_option", grub_cmd_dhcpopt,
N_("VAR INTERFACE NUMBER DESCRIPTION"),
N_("retrieve DHCP option and save it into VAR. If VAR is - then print the value."));
}
void
grub_bootp_fini (void)
{
grub_unregister_command (cmd_getdhcp);
grub_unregister_command (cmd_bootp);
grub_unregister_command (cmd_dhcp);
}
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