Add forgotten file
This commit is contained in:
Vladimir 'phcoder' Serbinenko
parent
038ec56a31
commit
078d2b2e68
1 changed files with 424 additions and 0 deletions
424
grub-core/net/dns.c
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424
grub-core/net/dns.c
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/*
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* GRUB -- GRand Unified Bootloader
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* Copyright (C) 2010,2011 Free Software Foundation, Inc.
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*
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* GRUB is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* GRUB is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with GRUB. If not, see <http://www.gnu.org/licenses/>.
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*/
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#include <grub/net.h>
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#include <grub/net/udp.h>
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#include <grub/command.h>
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#include <grub/i18n.h>
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#include <grub/err.h>
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struct dns_cache_element
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{
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char *name;
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grub_size_t naddresses;
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struct grub_net_network_level_address *addresses;
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struct grub_net_network_level_address *source;
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grub_uint64_t limit_time;
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};
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struct dns_header
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{
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grub_uint16_t id;
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grub_uint8_t flags;
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grub_uint8_t ra_z_r_code;
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grub_uint16_t qdcount;
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grub_uint16_t ancount;
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grub_uint16_t nscount;
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grub_uint16_t arcount;
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} __attribute__ ((packed));
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enum
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{
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FLAGS_RESPONSE = 0x80,
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FLAGS_OPCODE = 0x78,
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FLAGS_RD = 0x01
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};
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enum
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{
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ERRCODE_MASK = 0x0f
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};
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enum
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{
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DNS_PORT = 53
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};
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struct recv_data
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{
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grub_size_t *naddresses;
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struct grub_net_network_level_address **addresses;
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int cache;
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grub_uint16_t id;
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int dns_err;
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const char *name;
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};
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static int
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check_name (const grub_uint8_t *name_at, const grub_uint8_t *head,
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const grub_uint8_t *tail, const char *check_with)
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{
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const char *readable_ptr = check_with;
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const grub_uint8_t *ptr;
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int bytes_processed = 0;
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for (ptr = name_at; ptr < tail && bytes_processed < tail - head + 2; )
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{
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/* End marker. */
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if (!*ptr)
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return (*readable_ptr == 0);
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if (*ptr & 0xc0)
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{
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bytes_processed += 2;
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if (ptr + 1 >= tail)
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return 0;
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ptr = head + (((ptr[0] & 0x3f) << 8) | ptr[1]);
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continue;
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}
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if (grub_memcmp (ptr + 1, readable_ptr, *ptr) != 0)
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return 0;
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if (grub_memchr (ptr + 1, 0, *ptr)
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|| grub_memchr (ptr + 1, '.', *ptr))
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return 0;
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if (readable_ptr[*ptr] != '.' && readable_ptr[*ptr] != 0)
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return 0;
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bytes_processed += *ptr + 1;
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readable_ptr += *ptr;
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if (*readable_ptr)
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readable_ptr++;
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ptr += *ptr + 1;
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}
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return 0;
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}
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static grub_err_t
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recv_hook (grub_net_udp_socket_t sock __attribute__ ((unused)),
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struct grub_net_buff *nb,
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void *data_)
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{
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struct dns_header *head;
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struct recv_data *data = data_;
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int i, j;
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grub_uint8_t *ptr;
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head = (struct dns_header *) nb->data;
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ptr = (grub_uint8_t *) (head + 1);
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if (ptr >= nb->tail)
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{
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grub_netbuff_free (nb);
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return GRUB_ERR_NONE;
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}
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if (head->id != data->id)
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{
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grub_netbuff_free (nb);
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return GRUB_ERR_NONE;
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}
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if (!(head->flags & FLAGS_RESPONSE) || (head->flags & FLAGS_OPCODE))
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{
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grub_netbuff_free (nb);
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return GRUB_ERR_NONE;
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}
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if (head->ra_z_r_code & ERRCODE_MASK)
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{
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data->dns_err = 1;
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grub_netbuff_free (nb);
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return GRUB_ERR_NONE;
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}
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for (i = 0; i < grub_cpu_to_be16 (head->qdcount); i++)
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{
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if (ptr >= nb->tail)
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{
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grub_netbuff_free (nb);
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return GRUB_ERR_NONE;
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}
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while (ptr < nb->tail && !((*ptr & 0xc0) || *ptr == 0))
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ptr += *ptr + 1;
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if (ptr < nb->tail && (*ptr & 0xc0))
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ptr++;
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ptr++;
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ptr += 4;
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}
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*data->addresses = grub_malloc (sizeof ((*data->addresses)[0])
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* grub_cpu_to_be16 (head->ancount));
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if (!*data->addresses)
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{
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grub_errno = GRUB_ERR_NONE;
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grub_netbuff_free (nb);
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return GRUB_ERR_NONE;
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}
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for (i = 0; i < grub_cpu_to_be16 (head->ancount); i++)
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{
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int ignored = 0;
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int is_ipv6 = 0;
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grub_uint32_t ttl = 0;
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grub_uint16_t length;
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if (ptr >= nb->tail)
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{
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if (!*data->naddresses)
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grub_free (*data->addresses);
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return GRUB_ERR_NONE;
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}
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ignored = !check_name (ptr, nb->data, nb->tail, data->name);
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while (ptr < nb->tail && !((*ptr & 0xc0) || *ptr == 0))
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ptr += *ptr + 1;
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if (ptr < nb->tail && (*ptr & 0xc0))
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ptr++;
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ptr++;
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if (ptr + 10 >= nb->tail)
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{
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if (!*data->naddresses)
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grub_free (*data->addresses);
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grub_netbuff_free (nb);
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return GRUB_ERR_NONE;
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}
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if (*ptr++ != 0)
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ignored = 1;
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if (*ptr != 1 && *ptr != 28)
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ignored = 1;
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if (*ptr == 28)
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is_ipv6 = 1;
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ptr++;
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if (*ptr++ != 0)
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ignored = 1;
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if (*ptr++ != 1)
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ignored = 1;
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for (j = 0; j < 4; j++)
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{
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ttl >>= 8;
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ttl = *ptr++ << 28;
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}
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length = *ptr++ << 8;
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length |= *ptr++;
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if (ptr + length > nb->tail)
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{
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if (!*data->naddresses)
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grub_free (*data->addresses);
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grub_netbuff_free (nb);
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return GRUB_ERR_NONE;
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}
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if (!ignored && !is_ipv6 && length == 4)
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{
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(*data->addresses)[*data->naddresses].type
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= GRUB_NET_NETWORK_LEVEL_PROTOCOL_IPV4;
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grub_memcpy (&(*data->addresses)[*data->naddresses].ipv4,
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ptr, 4);
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(*data->naddresses)++;
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}
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if (!ignored && is_ipv6 && length == 16)
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{
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(*data->addresses)[*data->naddresses].type
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= GRUB_NET_NETWORK_LEVEL_PROTOCOL_IPV6;
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grub_memcpy (&(*data->addresses)[*data->naddresses].ipv6,
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ptr, 16);
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(*data->naddresses)++;
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}
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ptr += length;
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}
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grub_netbuff_free (nb);
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return GRUB_ERR_NONE;
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}
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grub_err_t
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grub_net_dns_lookup (const char *name,
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const struct grub_net_network_level_address *servers,
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grub_size_t n_servers,
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grub_size_t *naddresses,
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struct grub_net_network_level_address **addresses,
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int cache)
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{
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grub_size_t send_servers = 0;
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grub_size_t i, j;
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struct grub_net_buff *nb;
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grub_net_udp_socket_t sockets[n_servers];
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grub_uint8_t *optr;
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const char *iptr;
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struct dns_header *head;
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static grub_uint16_t id = 1;
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grub_err_t err = GRUB_ERR_NONE;
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struct recv_data data = {naddresses, addresses, cache,
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grub_cpu_to_be16 (id++), 0, name};
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grub_uint8_t *nbd;
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int have_server = 0;
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*naddresses = 0;
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/* if (cache && cache_lookup (name, servers, n_servers, addresses))
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return GRUB_ERR_NONE;*/
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nb = grub_netbuff_alloc (GRUB_NET_OUR_MAX_IP_HEADER_SIZE
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+ GRUB_NET_MAX_LINK_HEADER_SIZE
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+ GRUB_NET_UDP_HEADER_SIZE
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+ sizeof (struct dns_header)
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+ grub_strlen (name) + 2 + 4
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+ 2 + 4);
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if (!nb)
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return grub_errno;
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grub_netbuff_reserve (nb, GRUB_NET_OUR_MAX_IP_HEADER_SIZE
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+ GRUB_NET_MAX_LINK_HEADER_SIZE
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+ GRUB_NET_UDP_HEADER_SIZE);
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grub_netbuff_put (nb, sizeof (struct dns_header)
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+ grub_strlen (name) + 2 + 4 + 2 + 4);
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head = (struct dns_header *) nb->data;
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optr = (grub_uint8_t *) (head + 1);
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for (iptr = name; *iptr; )
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{
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const char *dot;
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dot = grub_strchr (iptr, '.');
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if (!dot)
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dot = iptr + grub_strlen (iptr);
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if ((dot - iptr) >= 64)
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return grub_error (GRUB_ERR_BAD_ARGUMENT,
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"domain component is too long");
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*optr = (dot - iptr);
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optr++;
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grub_memcpy (optr, iptr, dot - iptr);
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optr += dot - iptr;
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iptr = dot;
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if (*iptr)
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iptr++;
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}
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*optr++ = 0;
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/* Type: A. */
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*optr++ = 0;
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*optr++ = 1;
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/* Class. */
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*optr++ = 0;
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*optr++ = 1;
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/* Compressed name. */
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*optr++ = 0xc0;
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*optr++ = 0x0c;
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/* Type: AAAA. */
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*optr++ = 0;
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*optr++ = 28;
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/* Class. */
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*optr++ = 0;
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*optr++ = 1;
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head->id = data.id;
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head->flags = FLAGS_RD;
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head->ra_z_r_code = 0;
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head->qdcount = grub_cpu_to_be16_compile_time (2);
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head->ancount = grub_cpu_to_be16_compile_time (0);
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head->nscount = grub_cpu_to_be16_compile_time (0);
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head->arcount = grub_cpu_to_be16_compile_time (0);
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nbd = nb->data;
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for (i = 0; i < n_servers * 4; i++)
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{
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/* Connect to a next server. */
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while (!(i & 1) && send_servers < n_servers)
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{
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sockets[send_servers] = grub_net_udp_open (servers[send_servers],
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DNS_PORT,
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recv_hook,
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&data);
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send_servers++;
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if (!sockets[send_servers - 1])
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{
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err = grub_errno;
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grub_errno = GRUB_ERR_NONE;
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}
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else
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{
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have_server = 1;
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break;
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}
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}
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if (!have_server)
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goto out;
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if (*data.naddresses)
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goto out;
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for (j = 0; j < send_servers; j++)
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{
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grub_err_t err2;
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if (!sockets[j])
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continue;
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nb->data = nbd;
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err2 = grub_net_send_udp_packet (sockets[j], nb);
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if (err2)
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{
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grub_errno = GRUB_ERR_NONE;
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err = err2;
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}
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if (*data.naddresses)
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goto out;
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}
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grub_net_poll_cards (200);
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}
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out:
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grub_netbuff_free (nb);
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for (j = 0; j < send_servers; j++)
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grub_net_udp_close (sockets[j]);
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if (*data.naddresses)
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return GRUB_ERR_NONE;
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if (data.dns_err)
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return grub_error (GRUB_ERR_NET_NO_DOMAIN, "no DNS domain found");
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if (err)
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{
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grub_errno = err;
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return err;
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}
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return grub_error (GRUB_ERR_TIMEOUT, "no DNS reply received");
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}
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static grub_err_t
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grub_cmd_nslookup (struct grub_command *cmd __attribute__ ((unused)),
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int argc, char **args)
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{
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grub_err_t err;
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struct grub_net_network_level_address server;
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grub_size_t naddresses, i;
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struct grub_net_network_level_address *addresses;
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if (argc != 2)
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return grub_error (GRUB_ERR_BAD_ARGUMENT, "2 arguments expected");
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err = grub_net_resolve_address (args[1], &server);
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if (err)
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return err;
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err = grub_net_dns_lookup (args[0], &server, 1, &naddresses, &addresses, 0);
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if (err)
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return err;
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for (i = 0; i < naddresses; i++)
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{
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char buf[GRUB_NET_MAX_STR_ADDR_LEN];
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grub_net_addr_to_str (&addresses[i], buf);
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grub_printf ("%s\n", buf);
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}
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return GRUB_ERR_NONE;
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}
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static grub_command_t cmd;
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void
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grub_dns_init (void)
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{
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cmd = grub_register_command ("net_nslookup", grub_cmd_nslookup,
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"ADDRESS DNSSERVER",
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N_("perform a DNS lookup"));
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}
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void
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grub_dns_fini (void)
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{
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grub_unregister_command (cmd);
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}
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