424 lines
9.9 KiB
C
424 lines
9.9 KiB
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/udp.h>
|
|
#include <grub/command.h>
|
|
#include <grub/i18n.h>
|
|
#include <grub/err.h>
|
|
|
|
struct dns_cache_element
|
|
{
|
|
char *name;
|
|
grub_size_t naddresses;
|
|
struct grub_net_network_level_address *addresses;
|
|
struct grub_net_network_level_address *source;
|
|
grub_uint64_t limit_time;
|
|
};
|
|
|
|
struct dns_header
|
|
{
|
|
grub_uint16_t id;
|
|
grub_uint8_t flags;
|
|
grub_uint8_t ra_z_r_code;
|
|
grub_uint16_t qdcount;
|
|
grub_uint16_t ancount;
|
|
grub_uint16_t nscount;
|
|
grub_uint16_t arcount;
|
|
} __attribute__ ((packed));
|
|
|
|
enum
|
|
{
|
|
FLAGS_RESPONSE = 0x80,
|
|
FLAGS_OPCODE = 0x78,
|
|
FLAGS_RD = 0x01
|
|
};
|
|
|
|
enum
|
|
{
|
|
ERRCODE_MASK = 0x0f
|
|
};
|
|
|
|
enum
|
|
{
|
|
DNS_PORT = 53
|
|
};
|
|
|
|
struct recv_data
|
|
{
|
|
grub_size_t *naddresses;
|
|
struct grub_net_network_level_address **addresses;
|
|
int cache;
|
|
grub_uint16_t id;
|
|
int dns_err;
|
|
const char *name;
|
|
};
|
|
|
|
static int
|
|
check_name (const grub_uint8_t *name_at, const grub_uint8_t *head,
|
|
const grub_uint8_t *tail, const char *check_with)
|
|
{
|
|
const char *readable_ptr = check_with;
|
|
const grub_uint8_t *ptr;
|
|
int bytes_processed = 0;
|
|
for (ptr = name_at; ptr < tail && bytes_processed < tail - head + 2; )
|
|
{
|
|
/* End marker. */
|
|
if (!*ptr)
|
|
return (*readable_ptr == 0);
|
|
if (*ptr & 0xc0)
|
|
{
|
|
bytes_processed += 2;
|
|
if (ptr + 1 >= tail)
|
|
return 0;
|
|
ptr = head + (((ptr[0] & 0x3f) << 8) | ptr[1]);
|
|
continue;
|
|
}
|
|
if (grub_memcmp (ptr + 1, readable_ptr, *ptr) != 0)
|
|
return 0;
|
|
if (grub_memchr (ptr + 1, 0, *ptr)
|
|
|| grub_memchr (ptr + 1, '.', *ptr))
|
|
return 0;
|
|
if (readable_ptr[*ptr] != '.' && readable_ptr[*ptr] != 0)
|
|
return 0;
|
|
bytes_processed += *ptr + 1;
|
|
readable_ptr += *ptr;
|
|
if (*readable_ptr)
|
|
readable_ptr++;
|
|
ptr += *ptr + 1;
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
static grub_err_t
|
|
recv_hook (grub_net_udp_socket_t sock __attribute__ ((unused)),
|
|
struct grub_net_buff *nb,
|
|
void *data_)
|
|
{
|
|
struct dns_header *head;
|
|
struct recv_data *data = data_;
|
|
int i, j;
|
|
grub_uint8_t *ptr;
|
|
|
|
head = (struct dns_header *) nb->data;
|
|
ptr = (grub_uint8_t *) (head + 1);
|
|
if (ptr >= nb->tail)
|
|
{
|
|
grub_netbuff_free (nb);
|
|
return GRUB_ERR_NONE;
|
|
}
|
|
|
|
if (head->id != data->id)
|
|
{
|
|
grub_netbuff_free (nb);
|
|
return GRUB_ERR_NONE;
|
|
}
|
|
if (!(head->flags & FLAGS_RESPONSE) || (head->flags & FLAGS_OPCODE))
|
|
{
|
|
grub_netbuff_free (nb);
|
|
return GRUB_ERR_NONE;
|
|
}
|
|
if (head->ra_z_r_code & ERRCODE_MASK)
|
|
{
|
|
data->dns_err = 1;
|
|
grub_netbuff_free (nb);
|
|
return GRUB_ERR_NONE;
|
|
}
|
|
for (i = 0; i < grub_cpu_to_be16 (head->qdcount); i++)
|
|
{
|
|
if (ptr >= nb->tail)
|
|
{
|
|
grub_netbuff_free (nb);
|
|
return GRUB_ERR_NONE;
|
|
}
|
|
while (ptr < nb->tail && !((*ptr & 0xc0) || *ptr == 0))
|
|
ptr += *ptr + 1;
|
|
if (ptr < nb->tail && (*ptr & 0xc0))
|
|
ptr++;
|
|
ptr++;
|
|
ptr += 4;
|
|
}
|
|
*data->addresses = grub_malloc (sizeof ((*data->addresses)[0])
|
|
* grub_cpu_to_be16 (head->ancount));
|
|
if (!*data->addresses)
|
|
{
|
|
grub_errno = GRUB_ERR_NONE;
|
|
grub_netbuff_free (nb);
|
|
return GRUB_ERR_NONE;
|
|
}
|
|
for (i = 0; i < grub_cpu_to_be16 (head->ancount); i++)
|
|
{
|
|
int ignored = 0;
|
|
int is_ipv6 = 0;
|
|
grub_uint32_t ttl = 0;
|
|
grub_uint16_t length;
|
|
if (ptr >= nb->tail)
|
|
{
|
|
if (!*data->naddresses)
|
|
grub_free (*data->addresses);
|
|
return GRUB_ERR_NONE;
|
|
}
|
|
ignored = !check_name (ptr, nb->data, nb->tail, data->name);
|
|
while (ptr < nb->tail && !((*ptr & 0xc0) || *ptr == 0))
|
|
ptr += *ptr + 1;
|
|
if (ptr < nb->tail && (*ptr & 0xc0))
|
|
ptr++;
|
|
ptr++;
|
|
if (ptr + 10 >= nb->tail)
|
|
{
|
|
if (!*data->naddresses)
|
|
grub_free (*data->addresses);
|
|
grub_netbuff_free (nb);
|
|
return GRUB_ERR_NONE;
|
|
}
|
|
if (*ptr++ != 0)
|
|
ignored = 1;
|
|
if (*ptr != 1 && *ptr != 28)
|
|
ignored = 1;
|
|
if (*ptr == 28)
|
|
is_ipv6 = 1;
|
|
ptr++;
|
|
if (*ptr++ != 0)
|
|
ignored = 1;
|
|
if (*ptr++ != 1)
|
|
ignored = 1;
|
|
for (j = 0; j < 4; j++)
|
|
{
|
|
ttl >>= 8;
|
|
ttl = *ptr++ << 28;
|
|
}
|
|
length = *ptr++ << 8;
|
|
length |= *ptr++;
|
|
if (ptr + length > nb->tail)
|
|
{
|
|
if (!*data->naddresses)
|
|
grub_free (*data->addresses);
|
|
grub_netbuff_free (nb);
|
|
return GRUB_ERR_NONE;
|
|
}
|
|
if (!ignored && !is_ipv6 && length == 4)
|
|
{
|
|
(*data->addresses)[*data->naddresses].type
|
|
= GRUB_NET_NETWORK_LEVEL_PROTOCOL_IPV4;
|
|
grub_memcpy (&(*data->addresses)[*data->naddresses].ipv4,
|
|
ptr, 4);
|
|
(*data->naddresses)++;
|
|
}
|
|
if (!ignored && is_ipv6 && length == 16)
|
|
{
|
|
(*data->addresses)[*data->naddresses].type
|
|
= GRUB_NET_NETWORK_LEVEL_PROTOCOL_IPV6;
|
|
grub_memcpy (&(*data->addresses)[*data->naddresses].ipv6,
|
|
ptr, 16);
|
|
(*data->naddresses)++;
|
|
}
|
|
ptr += length;
|
|
}
|
|
grub_netbuff_free (nb);
|
|
return GRUB_ERR_NONE;
|
|
}
|
|
|
|
grub_err_t
|
|
grub_net_dns_lookup (const char *name,
|
|
const struct grub_net_network_level_address *servers,
|
|
grub_size_t n_servers,
|
|
grub_size_t *naddresses,
|
|
struct grub_net_network_level_address **addresses,
|
|
int cache)
|
|
{
|
|
grub_size_t send_servers = 0;
|
|
grub_size_t i, j;
|
|
struct grub_net_buff *nb;
|
|
grub_net_udp_socket_t sockets[n_servers];
|
|
grub_uint8_t *optr;
|
|
const char *iptr;
|
|
struct dns_header *head;
|
|
static grub_uint16_t id = 1;
|
|
grub_err_t err = GRUB_ERR_NONE;
|
|
struct recv_data data = {naddresses, addresses, cache,
|
|
grub_cpu_to_be16 (id++), 0, name};
|
|
grub_uint8_t *nbd;
|
|
int have_server = 0;
|
|
|
|
*naddresses = 0;
|
|
/* if (cache && cache_lookup (name, servers, n_servers, addresses))
|
|
return GRUB_ERR_NONE;*/
|
|
|
|
nb = grub_netbuff_alloc (GRUB_NET_OUR_MAX_IP_HEADER_SIZE
|
|
+ GRUB_NET_MAX_LINK_HEADER_SIZE
|
|
+ GRUB_NET_UDP_HEADER_SIZE
|
|
+ sizeof (struct dns_header)
|
|
+ grub_strlen (name) + 2 + 4
|
|
+ 2 + 4);
|
|
if (!nb)
|
|
return grub_errno;
|
|
grub_netbuff_reserve (nb, GRUB_NET_OUR_MAX_IP_HEADER_SIZE
|
|
+ GRUB_NET_MAX_LINK_HEADER_SIZE
|
|
+ GRUB_NET_UDP_HEADER_SIZE);
|
|
grub_netbuff_put (nb, sizeof (struct dns_header)
|
|
+ grub_strlen (name) + 2 + 4 + 2 + 4);
|
|
head = (struct dns_header *) nb->data;
|
|
optr = (grub_uint8_t *) (head + 1);
|
|
for (iptr = name; *iptr; )
|
|
{
|
|
const char *dot;
|
|
dot = grub_strchr (iptr, '.');
|
|
if (!dot)
|
|
dot = iptr + grub_strlen (iptr);
|
|
if ((dot - iptr) >= 64)
|
|
return grub_error (GRUB_ERR_BAD_ARGUMENT,
|
|
"domain component is too long");
|
|
*optr = (dot - iptr);
|
|
optr++;
|
|
grub_memcpy (optr, iptr, dot - iptr);
|
|
optr += dot - iptr;
|
|
iptr = dot;
|
|
if (*iptr)
|
|
iptr++;
|
|
}
|
|
*optr++ = 0;
|
|
|
|
/* Type: A. */
|
|
*optr++ = 0;
|
|
*optr++ = 1;
|
|
|
|
/* Class. */
|
|
*optr++ = 0;
|
|
*optr++ = 1;
|
|
|
|
/* Compressed name. */
|
|
*optr++ = 0xc0;
|
|
*optr++ = 0x0c;
|
|
/* Type: AAAA. */
|
|
*optr++ = 0;
|
|
*optr++ = 28;
|
|
|
|
/* Class. */
|
|
*optr++ = 0;
|
|
*optr++ = 1;
|
|
|
|
head->id = data.id;
|
|
head->flags = FLAGS_RD;
|
|
head->ra_z_r_code = 0;
|
|
head->qdcount = grub_cpu_to_be16_compile_time (2);
|
|
head->ancount = grub_cpu_to_be16_compile_time (0);
|
|
head->nscount = grub_cpu_to_be16_compile_time (0);
|
|
head->arcount = grub_cpu_to_be16_compile_time (0);
|
|
|
|
nbd = nb->data;
|
|
|
|
for (i = 0; i < n_servers * 4; i++)
|
|
{
|
|
/* Connect to a next server. */
|
|
while (!(i & 1) && send_servers < n_servers)
|
|
{
|
|
sockets[send_servers] = grub_net_udp_open (servers[send_servers],
|
|
DNS_PORT,
|
|
recv_hook,
|
|
&data);
|
|
send_servers++;
|
|
if (!sockets[send_servers - 1])
|
|
{
|
|
err = grub_errno;
|
|
grub_errno = GRUB_ERR_NONE;
|
|
}
|
|
else
|
|
{
|
|
have_server = 1;
|
|
break;
|
|
}
|
|
}
|
|
if (!have_server)
|
|
goto out;
|
|
if (*data.naddresses)
|
|
goto out;
|
|
for (j = 0; j < send_servers; j++)
|
|
{
|
|
grub_err_t err2;
|
|
if (!sockets[j])
|
|
continue;
|
|
nb->data = nbd;
|
|
err2 = grub_net_send_udp_packet (sockets[j], nb);
|
|
if (err2)
|
|
{
|
|
grub_errno = GRUB_ERR_NONE;
|
|
err = err2;
|
|
}
|
|
if (*data.naddresses)
|
|
goto out;
|
|
}
|
|
grub_net_poll_cards (200);
|
|
}
|
|
out:
|
|
grub_netbuff_free (nb);
|
|
for (j = 0; j < send_servers; j++)
|
|
grub_net_udp_close (sockets[j]);
|
|
if (*data.naddresses)
|
|
return GRUB_ERR_NONE;
|
|
if (data.dns_err)
|
|
return grub_error (GRUB_ERR_NET_NO_DOMAIN, "no DNS domain found");
|
|
|
|
if (err)
|
|
{
|
|
grub_errno = err;
|
|
return err;
|
|
}
|
|
return grub_error (GRUB_ERR_TIMEOUT, "no DNS reply received");
|
|
}
|
|
|
|
static grub_err_t
|
|
grub_cmd_nslookup (struct grub_command *cmd __attribute__ ((unused)),
|
|
int argc, char **args)
|
|
{
|
|
grub_err_t err;
|
|
struct grub_net_network_level_address server;
|
|
grub_size_t naddresses, i;
|
|
struct grub_net_network_level_address *addresses;
|
|
if (argc != 2)
|
|
return grub_error (GRUB_ERR_BAD_ARGUMENT, "2 arguments expected");
|
|
err = grub_net_resolve_address (args[1], &server);
|
|
if (err)
|
|
return err;
|
|
|
|
err = grub_net_dns_lookup (args[0], &server, 1, &naddresses, &addresses, 0);
|
|
if (err)
|
|
return err;
|
|
for (i = 0; i < naddresses; i++)
|
|
{
|
|
char buf[GRUB_NET_MAX_STR_ADDR_LEN];
|
|
grub_net_addr_to_str (&addresses[i], buf);
|
|
grub_printf ("%s\n", buf);
|
|
}
|
|
return GRUB_ERR_NONE;
|
|
}
|
|
|
|
static grub_command_t cmd;
|
|
|
|
void
|
|
grub_dns_init (void)
|
|
{
|
|
cmd = grub_register_command ("net_nslookup", grub_cmd_nslookup,
|
|
"ADDRESS DNSSERVER",
|
|
N_("perform a DNS lookup"));
|
|
}
|
|
|
|
void
|
|
grub_dns_fini (void)
|
|
{
|
|
grub_unregister_command (cmd);
|
|
}
|