| 1 | /*
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| 2 | * Copyright (c) 2013 Jiri Svoboda
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| 3 | * All rights reserved.
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| 4 | *
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| 5 | * Redistribution and use in source and binary forms, with or without
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| 6 | * modification, are permitted provided that the following conditions
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| 7 | * are met:
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| 8 | *
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| 9 | * - Redistributions of source code must retain the above copyright
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| 10 | * notice, this list of conditions and the following disclaimer.
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| 11 | * - Redistributions in binary form must reproduce the above copyright
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| 12 | * notice, this list of conditions and the following disclaimer in the
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| 13 | * documentation and/or other materials provided with the distribution.
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| 14 | * - The name of the author may not be used to endorse or promote products
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| 15 | * derived from this software without specific prior written permission.
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| 16 | *
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| 17 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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| 18 | * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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| 19 | * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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| 20 | * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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| 21 | * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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| 22 | * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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| 23 | * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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| 24 | * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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| 25 | * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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| 26 | * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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| 27 | */
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| 28 |
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| 29 | /** @addtogroup dnsres
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| 30 | * @{
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| 31 | */
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| 32 | /**
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| 33 | * @file
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| 34 | */
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| 35 |
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| 36 | #include <errno.h>
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| 37 | #include <io/log.h>
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| 38 | #include <mem.h>
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| 39 | #include <stdlib.h>
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| 40 | #include <str.h>
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| 41 | #include <net/socket_codes.h>
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| 42 | #include "dns_msg.h"
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| 43 | #include "dns_std.h"
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| 44 | #include "dns_type.h"
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| 45 | #include "query.h"
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| 46 | #include "transport.h"
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| 47 |
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| 48 | static uint16_t msg_id;
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| 49 |
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| 50 | static int dns_name_query(const char *name, dns_qtype_t qtype,
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| 51 | dns_host_info_t *info)
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| 52 | {
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| 53 | /* Start with the caller-provided name */
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| 54 | char *sname = str_dup(name);
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| 55 | if (sname == NULL)
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| 56 | return ENOMEM;
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| 57 |
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| 58 | char *qname = str_dup(name);
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| 59 | if (qname == NULL) {
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| 60 | free(sname);
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| 61 | return ENOMEM;
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| 62 | }
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| 63 |
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| 64 | dns_question_t *question = calloc(1, sizeof(dns_question_t));
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| 65 | if (question == NULL) {
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| 66 | free(qname);
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| 67 | free(sname);
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| 68 | return ENOMEM;
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| 69 | }
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| 70 |
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| 71 | question->qname = qname;
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| 72 | question->qtype = qtype;
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| 73 | question->qclass = DC_IN;
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| 74 |
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| 75 | dns_message_t *msg = dns_message_new();
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| 76 | if (msg == NULL) {
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| 77 | free(question);
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| 78 | free(qname);
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| 79 | free(sname);
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| 80 | return ENOMEM;
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| 81 | }
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| 82 |
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| 83 | msg->id = msg_id++;
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| 84 | msg->qr = QR_QUERY;
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| 85 | msg->opcode = OPC_QUERY;
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| 86 | msg->aa = false;
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| 87 | msg->tc = false;
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| 88 | msg->rd = true;
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| 89 | msg->ra = false;
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| 90 |
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| 91 | list_append(&question->msg, &msg->question);
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| 92 |
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| 93 | dns_message_t *amsg;
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| 94 | int rc = dns_request(msg, &amsg);
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| 95 | if (rc != EOK) {
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| 96 | dns_message_destroy(msg);
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| 97 | free(sname);
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| 98 | return rc;
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| 99 | }
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| 100 |
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| 101 | list_foreach(amsg->answer, link) {
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| 102 | dns_rr_t *rr = list_get_instance(link, dns_rr_t, msg);
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| 103 |
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| 104 | log_msg(LOG_DEFAULT, LVL_DEBUG, " - '%s' %u/%u, dsize %zu",
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| 105 | rr->name, rr->rtype, rr->rclass, rr->rdata_size);
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| 106 |
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| 107 | if ((rr->rtype == DTYPE_CNAME) && (rr->rclass == DC_IN) &&
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| 108 | (str_cmp(rr->name, sname) == 0)) {
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| 109 |
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| 110 | log_msg(LOG_DEFAULT, LVL_DEBUG, "decode cname (%p, %zu, %zu)",
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| 111 | amsg->pdu.data, amsg->pdu.size, rr->roff);
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| 112 |
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| 113 | char *cname;
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| 114 | size_t eoff;
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| 115 | rc = dns_name_decode(&amsg->pdu, rr->roff, &cname, &eoff);
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| 116 | if (rc != EOK) {
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| 117 | assert((rc == EINVAL) || (rc == ENOMEM));
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| 118 |
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| 119 | log_msg(LOG_DEFAULT, LVL_DEBUG, "error decoding cname");
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| 120 |
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| 121 | dns_message_destroy(msg);
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| 122 | dns_message_destroy(amsg);
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| 123 | free(sname);
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| 124 |
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| 125 | return rc;
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| 126 | }
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| 127 |
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| 128 | log_msg(LOG_DEFAULT, LVL_DEBUG, "name = '%s' "
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| 129 | "cname = '%s'", sname, cname);
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| 130 |
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| 131 | /* Continue looking for the more canonical name */
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| 132 | free(sname);
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| 133 | sname = cname;
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| 134 | }
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| 135 |
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| 136 | if ((qtype == DTYPE_A) && (rr->rtype == DTYPE_A) &&
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| 137 | (rr->rclass == DC_IN) && (rr->rdata_size == sizeof(addr32_t)) &&
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| 138 | (str_cmp(rr->name, sname) == 0)) {
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| 139 |
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| 140 | info->cname = str_dup(rr->name);
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| 141 | if (info->cname == NULL) {
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| 142 | dns_message_destroy(msg);
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| 143 | dns_message_destroy(amsg);
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| 144 | free(sname);
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| 145 |
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| 146 | return ENOMEM;
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| 147 | }
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| 148 |
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| 149 | inet_addr_set(dns_uint32_t_decode(rr->rdata, rr->rdata_size),
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| 150 | &info->addr);
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| 151 |
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| 152 | dns_message_destroy(msg);
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| 153 | dns_message_destroy(amsg);
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| 154 | free(sname);
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| 155 |
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| 156 | return EOK;
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| 157 | }
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| 158 |
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| 159 | if ((qtype == DTYPE_AAAA) && (rr->rtype == DTYPE_AAAA) &&
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| 160 | (rr->rclass == DC_IN) && (rr->rdata_size == sizeof(addr128_t)) &&
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| 161 | (str_cmp(rr->name, sname) == 0)) {
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| 162 |
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| 163 | info->cname = str_dup(rr->name);
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| 164 | if (info->cname == NULL) {
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| 165 | dns_message_destroy(msg);
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| 166 | dns_message_destroy(amsg);
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| 167 | free(sname);
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| 168 |
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| 169 | return ENOMEM;
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| 170 | }
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| 171 |
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| 172 | addr128_t addr;
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| 173 | dns_addr128_t_decode(rr->rdata, rr->rdata_size, addr);
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| 174 |
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| 175 | inet_addr_set6(addr, &info->addr);
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| 176 |
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| 177 | dns_message_destroy(msg);
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| 178 | dns_message_destroy(amsg);
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| 179 | free(sname);
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| 180 |
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| 181 | return EOK;
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| 182 | }
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| 183 | }
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| 184 |
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| 185 | log_msg(LOG_DEFAULT, LVL_DEBUG, "'%s' not resolved, fail", sname);
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| 186 |
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| 187 | dns_message_destroy(msg);
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| 188 | dns_message_destroy(amsg);
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| 189 | free(sname);
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| 190 |
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| 191 | return EIO;
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| 192 | }
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| 193 |
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| 194 | int dns_name2host(const char *name, dns_host_info_t **rinfo, uint16_t af)
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| 195 | {
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| 196 | dns_host_info_t *info = calloc(1, sizeof(dns_host_info_t));
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| 197 | if (info == NULL)
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| 198 | return ENOMEM;
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| 199 |
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| 200 | int rc;
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| 201 |
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| 202 | switch (af) {
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| 203 | case AF_NONE:
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| 204 | rc = dns_name_query(name, DTYPE_AAAA, info);
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| 205 |
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| 206 | if (rc != EOK)
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| 207 | rc = dns_name_query(name, DTYPE_A, info);
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| 208 |
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| 209 | break;
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| 210 | case AF_INET:
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| 211 | rc = dns_name_query(name, DTYPE_A, info);
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| 212 | break;
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| 213 | case AF_INET6:
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| 214 | rc = dns_name_query(name, DTYPE_AAAA, info);
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| 215 | break;
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| 216 | default:
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| 217 | rc = EINVAL;
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| 218 | }
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| 219 |
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| 220 | if (rc == EOK)
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| 221 | *rinfo = info;
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| 222 | else
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| 223 | free(info);
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| 224 |
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| 225 | return rc;
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| 226 | }
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| 227 |
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| 228 | void dns_hostinfo_destroy(dns_host_info_t *info)
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| 229 | {
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| 230 | free(info->cname);
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| 231 | free(info);
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| 232 | }
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| 233 |
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| 234 | /** @}
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| 235 | */
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