Rahul Dahiya / Mbed OS STM32F7 Ethernet

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mbed-os/features/netsocket/nsapi_dns.cpp@0:fb8047b156bb, 2020-01-15 (annotated)

Committer:
rahul_dahiya
Date:
Wed Jan 15 15:57:15 2020 +0530
Revision:
0:fb8047b156bb
STM32F7 LWIP

Who changed what in which revision?

UserRevisionLine numberNew contents of line
rahul_dahiya 0:fb8047b156bb 1 /* nsapi_dns.cpp
rahul_dahiya 0:fb8047b156bb 2 * Original work Copyright (c) 2013 Henry Leinen (henry[dot]leinen [at] online [dot] de)
rahul_dahiya 0:fb8047b156bb 3 * Modified work Copyright (c) 2015 ARM Limited
rahul_dahiya 0:fb8047b156bb 4 *
rahul_dahiya 0:fb8047b156bb 5 * Licensed under the Apache License, Version 2.0 (the "License");
rahul_dahiya 0:fb8047b156bb 6 * you may not use this file except in compliance with the License.
rahul_dahiya 0:fb8047b156bb 7 * You may obtain a copy of the License at
rahul_dahiya 0:fb8047b156bb 8 *
rahul_dahiya 0:fb8047b156bb 9 * http://www.apache.org/licenses/LICENSE-2.0
rahul_dahiya 0:fb8047b156bb 10 *
rahul_dahiya 0:fb8047b156bb 11 * Unless required by applicable law or agreed to in writing, software
rahul_dahiya 0:fb8047b156bb 12 * distributed under the License is distributed on an "AS IS" BASIS,
rahul_dahiya 0:fb8047b156bb 13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
rahul_dahiya 0:fb8047b156bb 14 * See the License for the specific language governing permissions and
rahul_dahiya 0:fb8047b156bb 15 * limitations under the License.
rahul_dahiya 0:fb8047b156bb 16 */
rahul_dahiya 0:fb8047b156bb 17 #include "nsapi_dns.h"
rahul_dahiya 0:fb8047b156bb 18 #include "netsocket/UDPSocket.h"
rahul_dahiya 0:fb8047b156bb 19 #include <string.h>
rahul_dahiya 0:fb8047b156bb 20 #include <stdlib.h>
rahul_dahiya 0:fb8047b156bb 21 #include <stdio.h>
rahul_dahiya 0:fb8047b156bb 22
rahul_dahiya 0:fb8047b156bb 23 #define CLASS_IN 1
rahul_dahiya 0:fb8047b156bb 24
rahul_dahiya 0:fb8047b156bb 25 #define RR_A 1
rahul_dahiya 0:fb8047b156bb 26 #define RR_AAAA 28
rahul_dahiya 0:fb8047b156bb 27
rahul_dahiya 0:fb8047b156bb 28 // DNS options
rahul_dahiya 0:fb8047b156bb 29 #define DNS_BUFFER_SIZE 512
rahul_dahiya 0:fb8047b156bb 30 #define DNS_TIMEOUT 5000
rahul_dahiya 0:fb8047b156bb 31 #define DNS_SERVERS_SIZE 5
rahul_dahiya 0:fb8047b156bb 32
rahul_dahiya 0:fb8047b156bb 33 nsapi_addr_t dns_servers[DNS_SERVERS_SIZE] = {
rahul_dahiya 0:fb8047b156bb 34 {NSAPI_IPv4, {8, 8, 8, 8}}, // Google
rahul_dahiya 0:fb8047b156bb 35 {NSAPI_IPv4, {209, 244, 0, 3}}, // Level 3
rahul_dahiya 0:fb8047b156bb 36 {NSAPI_IPv4, {84, 200, 69, 80}}, // DNS.WATCH
rahul_dahiya 0:fb8047b156bb 37 {NSAPI_IPv6, {0x20,0x01, 0x48,0x60, 0x48,0x60, 0,0, // Google
rahul_dahiya 0:fb8047b156bb 38 0,0, 0,0, 0,0, 0x88,0x88}},
rahul_dahiya 0:fb8047b156bb 39 {NSAPI_IPv6, {0x20,0x01, 0x16,0x08, 0,0x10, 0,0x25, // DNS.WATCH
rahul_dahiya 0:fb8047b156bb 40 0,0, 0,0, 0x1c,0x04, 0xb1,0x2f}},
rahul_dahiya 0:fb8047b156bb 41 };
rahul_dahiya 0:fb8047b156bb 42
rahul_dahiya 0:fb8047b156bb 43 // DNS server configuration
rahul_dahiya 0:fb8047b156bb 44 extern "C" nsapi_error_t nsapi_dns_add_server(nsapi_addr_t addr)
rahul_dahiya 0:fb8047b156bb 45 {
rahul_dahiya 0:fb8047b156bb 46 memmove(&dns_servers[1], &dns_servers[0],
rahul_dahiya 0:fb8047b156bb 47 (DNS_SERVERS_SIZE-1)*sizeof(nsapi_addr_t));
rahul_dahiya 0:fb8047b156bb 48
rahul_dahiya 0:fb8047b156bb 49 dns_servers[0] = addr;
rahul_dahiya 0:fb8047b156bb 50 return NSAPI_ERROR_OK;
rahul_dahiya 0:fb8047b156bb 51 }
rahul_dahiya 0:fb8047b156bb 52
rahul_dahiya 0:fb8047b156bb 53
rahul_dahiya 0:fb8047b156bb 54 // DNS packet parsing
rahul_dahiya 0:fb8047b156bb 55 static void dns_append_byte(uint8_t **p, uint8_t byte)
rahul_dahiya 0:fb8047b156bb 56 {
rahul_dahiya 0:fb8047b156bb 57 *(*p)++ = byte;
rahul_dahiya 0:fb8047b156bb 58 }
rahul_dahiya 0:fb8047b156bb 59
rahul_dahiya 0:fb8047b156bb 60 static void dns_append_word(uint8_t **p, uint16_t word)
rahul_dahiya 0:fb8047b156bb 61 {
rahul_dahiya 0:fb8047b156bb 62
rahul_dahiya 0:fb8047b156bb 63 dns_append_byte(p, 0xff & (word >> 8));
rahul_dahiya 0:fb8047b156bb 64 dns_append_byte(p, 0xff & (word >> 0));
rahul_dahiya 0:fb8047b156bb 65 }
rahul_dahiya 0:fb8047b156bb 66
rahul_dahiya 0:fb8047b156bb 67 static void dns_append_name(uint8_t **p, const char *name, uint8_t len)
rahul_dahiya 0:fb8047b156bb 68 {
rahul_dahiya 0:fb8047b156bb 69 dns_append_byte(p, len);
rahul_dahiya 0:fb8047b156bb 70 memcpy(*p, name, len);
rahul_dahiya 0:fb8047b156bb 71 *p += len;
rahul_dahiya 0:fb8047b156bb 72 }
rahul_dahiya 0:fb8047b156bb 73
rahul_dahiya 0:fb8047b156bb 74 static uint8_t dns_scan_byte(const uint8_t **p)
rahul_dahiya 0:fb8047b156bb 75 {
rahul_dahiya 0:fb8047b156bb 76 return *(*p)++;
rahul_dahiya 0:fb8047b156bb 77 }
rahul_dahiya 0:fb8047b156bb 78
rahul_dahiya 0:fb8047b156bb 79 static uint16_t dns_scan_word(const uint8_t **p)
rahul_dahiya 0:fb8047b156bb 80 {
rahul_dahiya 0:fb8047b156bb 81 uint16_t a = dns_scan_byte(p);
rahul_dahiya 0:fb8047b156bb 82 uint16_t b = dns_scan_byte(p);
rahul_dahiya 0:fb8047b156bb 83 return (a << 8) | b;
rahul_dahiya 0:fb8047b156bb 84 }
rahul_dahiya 0:fb8047b156bb 85
rahul_dahiya 0:fb8047b156bb 86
rahul_dahiya 0:fb8047b156bb 87 static void dns_append_question(uint8_t **p, const char *host, nsapi_version_t version)
rahul_dahiya 0:fb8047b156bb 88 {
rahul_dahiya 0:fb8047b156bb 89 // fill the header
rahul_dahiya 0:fb8047b156bb 90 dns_append_word(p, 1); // id = 1
rahul_dahiya 0:fb8047b156bb 91 dns_append_word(p, 0x0100); // flags = recursion required
rahul_dahiya 0:fb8047b156bb 92 dns_append_word(p, 1); // qdcount = 1
rahul_dahiya 0:fb8047b156bb 93 dns_append_word(p, 0); // ancount = 0
rahul_dahiya 0:fb8047b156bb 94 dns_append_word(p, 0); // nscount = 0
rahul_dahiya 0:fb8047b156bb 95 dns_append_word(p, 0); // arcount = 0
rahul_dahiya 0:fb8047b156bb 96
rahul_dahiya 0:fb8047b156bb 97 // fill out the question names
rahul_dahiya 0:fb8047b156bb 98 while (host[0]) {
rahul_dahiya 0:fb8047b156bb 99 size_t label_len = strcspn(host, ".");
rahul_dahiya 0:fb8047b156bb 100 dns_append_name(p, host, label_len);
rahul_dahiya 0:fb8047b156bb 101 host += label_len + (host[label_len] == '.');
rahul_dahiya 0:fb8047b156bb 102 }
rahul_dahiya 0:fb8047b156bb 103
rahul_dahiya 0:fb8047b156bb 104 dns_append_byte(p, 0);
rahul_dahiya 0:fb8047b156bb 105
rahul_dahiya 0:fb8047b156bb 106 // fill out question footer
rahul_dahiya 0:fb8047b156bb 107 if (version != NSAPI_IPv6) {
rahul_dahiya 0:fb8047b156bb 108 dns_append_word(p, RR_A); // qtype = ipv4
rahul_dahiya 0:fb8047b156bb 109 } else {
rahul_dahiya 0:fb8047b156bb 110 dns_append_word(p, RR_AAAA); // qtype = ipv6
rahul_dahiya 0:fb8047b156bb 111 }
rahul_dahiya 0:fb8047b156bb 112 dns_append_word(p, CLASS_IN);
rahul_dahiya 0:fb8047b156bb 113 }
rahul_dahiya 0:fb8047b156bb 114
rahul_dahiya 0:fb8047b156bb 115 static int dns_scan_response(const uint8_t **p, nsapi_addr_t *addr, unsigned addr_count)
rahul_dahiya 0:fb8047b156bb 116 {
rahul_dahiya 0:fb8047b156bb 117 // scan header
rahul_dahiya 0:fb8047b156bb 118 uint16_t id = dns_scan_word(p);
rahul_dahiya 0:fb8047b156bb 119 uint16_t flags = dns_scan_word(p);
rahul_dahiya 0:fb8047b156bb 120 bool qr = 0x1 & (flags >> 15);
rahul_dahiya 0:fb8047b156bb 121 uint8_t opcode = 0xf & (flags >> 11);
rahul_dahiya 0:fb8047b156bb 122 uint8_t rcode = 0xf & (flags >> 0);
rahul_dahiya 0:fb8047b156bb 123
rahul_dahiya 0:fb8047b156bb 124 uint16_t qdcount = dns_scan_word(p); // qdcount
rahul_dahiya 0:fb8047b156bb 125 uint16_t ancount = dns_scan_word(p); // ancount
rahul_dahiya 0:fb8047b156bb 126 dns_scan_word(p); // nscount
rahul_dahiya 0:fb8047b156bb 127 dns_scan_word(p); // arcount
rahul_dahiya 0:fb8047b156bb 128
rahul_dahiya 0:fb8047b156bb 129 // verify header is response to query
rahul_dahiya 0:fb8047b156bb 130 if (!(id == 1 && qr && opcode == 0 && rcode == 0)) {
rahul_dahiya 0:fb8047b156bb 131 return 0;
rahul_dahiya 0:fb8047b156bb 132 }
rahul_dahiya 0:fb8047b156bb 133
rahul_dahiya 0:fb8047b156bb 134 // skip questions
rahul_dahiya 0:fb8047b156bb 135 for (int i = 0; i < qdcount; i++) {
rahul_dahiya 0:fb8047b156bb 136 while (true) {
rahul_dahiya 0:fb8047b156bb 137 uint8_t len = dns_scan_byte(p);
rahul_dahiya 0:fb8047b156bb 138 if (len == 0) {
rahul_dahiya 0:fb8047b156bb 139 break;
rahul_dahiya 0:fb8047b156bb 140 }
rahul_dahiya 0:fb8047b156bb 141
rahul_dahiya 0:fb8047b156bb 142 *p += len;
rahul_dahiya 0:fb8047b156bb 143 }
rahul_dahiya 0:fb8047b156bb 144
rahul_dahiya 0:fb8047b156bb 145 dns_scan_word(p); // qtype
rahul_dahiya 0:fb8047b156bb 146 dns_scan_word(p); // qclass
rahul_dahiya 0:fb8047b156bb 147 }
rahul_dahiya 0:fb8047b156bb 148
rahul_dahiya 0:fb8047b156bb 149 // scan each response
rahul_dahiya 0:fb8047b156bb 150 unsigned count = 0;
rahul_dahiya 0:fb8047b156bb 151
rahul_dahiya 0:fb8047b156bb 152 for (int i = 0; i < ancount && count < addr_count; i++) {
rahul_dahiya 0:fb8047b156bb 153 while (true) {
rahul_dahiya 0:fb8047b156bb 154 uint8_t len = dns_scan_byte(p);
rahul_dahiya 0:fb8047b156bb 155 if (len == 0) {
rahul_dahiya 0:fb8047b156bb 156 break;
rahul_dahiya 0:fb8047b156bb 157 } else if (len & 0xc0) { // this is link
rahul_dahiya 0:fb8047b156bb 158 dns_scan_byte(p);
rahul_dahiya 0:fb8047b156bb 159 break;
rahul_dahiya 0:fb8047b156bb 160 }
rahul_dahiya 0:fb8047b156bb 161
rahul_dahiya 0:fb8047b156bb 162 *p += len;
rahul_dahiya 0:fb8047b156bb 163 }
rahul_dahiya 0:fb8047b156bb 164
rahul_dahiya 0:fb8047b156bb 165 uint16_t rtype = dns_scan_word(p); // rtype
rahul_dahiya 0:fb8047b156bb 166 uint16_t rclass = dns_scan_word(p); // rclass
rahul_dahiya 0:fb8047b156bb 167 *p += 4; // ttl
rahul_dahiya 0:fb8047b156bb 168 uint16_t rdlength = dns_scan_word(p); // rdlength
rahul_dahiya 0:fb8047b156bb 169
rahul_dahiya 0:fb8047b156bb 170 if (rtype == RR_A && rclass == CLASS_IN && rdlength == NSAPI_IPv4_BYTES) {
rahul_dahiya 0:fb8047b156bb 171 // accept A record
rahul_dahiya 0:fb8047b156bb 172 addr->version = NSAPI_IPv4;
rahul_dahiya 0:fb8047b156bb 173 for (int i = 0; i < NSAPI_IPv4_BYTES; i++) {
rahul_dahiya 0:fb8047b156bb 174 addr->bytes[i] = dns_scan_byte(p);
rahul_dahiya 0:fb8047b156bb 175 }
rahul_dahiya 0:fb8047b156bb 176
rahul_dahiya 0:fb8047b156bb 177 addr += 1;
rahul_dahiya 0:fb8047b156bb 178 count += 1;
rahul_dahiya 0:fb8047b156bb 179 } else if (rtype == RR_AAAA && rclass == CLASS_IN && rdlength == NSAPI_IPv6_BYTES) {
rahul_dahiya 0:fb8047b156bb 180 // accept AAAA record
rahul_dahiya 0:fb8047b156bb 181 addr->version = NSAPI_IPv6;
rahul_dahiya 0:fb8047b156bb 182 for (int i = 0; i < NSAPI_IPv6_BYTES; i++) {
rahul_dahiya 0:fb8047b156bb 183 addr->bytes[i] = dns_scan_byte(p);
rahul_dahiya 0:fb8047b156bb 184 }
rahul_dahiya 0:fb8047b156bb 185
rahul_dahiya 0:fb8047b156bb 186 addr += 1;
rahul_dahiya 0:fb8047b156bb 187 count += 1;
rahul_dahiya 0:fb8047b156bb 188 } else {
rahul_dahiya 0:fb8047b156bb 189 // skip unrecognized records
rahul_dahiya 0:fb8047b156bb 190 *p += rdlength;
rahul_dahiya 0:fb8047b156bb 191 }
rahul_dahiya 0:fb8047b156bb 192 }
rahul_dahiya 0:fb8047b156bb 193
rahul_dahiya 0:fb8047b156bb 194 return count;
rahul_dahiya 0:fb8047b156bb 195 }
rahul_dahiya 0:fb8047b156bb 196
rahul_dahiya 0:fb8047b156bb 197 // core query function
rahul_dahiya 0:fb8047b156bb 198 static nsapi_size_or_error_t nsapi_dns_query_multiple(NetworkStack *stack, const char *host,
rahul_dahiya 0:fb8047b156bb 199 nsapi_addr_t *addr, unsigned addr_count, nsapi_version_t version)
rahul_dahiya 0:fb8047b156bb 200 {
rahul_dahiya 0:fb8047b156bb 201 // check for valid host name
rahul_dahiya 0:fb8047b156bb 202 int host_len = host ? strlen(host) : 0;
rahul_dahiya 0:fb8047b156bb 203 if (host_len > 128 || host_len == 0) {
rahul_dahiya 0:fb8047b156bb 204 return NSAPI_ERROR_PARAMETER;
rahul_dahiya 0:fb8047b156bb 205 }
rahul_dahiya 0:fb8047b156bb 206
rahul_dahiya 0:fb8047b156bb 207 // create a udp socket
rahul_dahiya 0:fb8047b156bb 208 UDPSocket socket;
rahul_dahiya 0:fb8047b156bb 209 int err = socket.open(stack);
rahul_dahiya 0:fb8047b156bb 210 if (err) {
rahul_dahiya 0:fb8047b156bb 211 return err;
rahul_dahiya 0:fb8047b156bb 212 }
rahul_dahiya 0:fb8047b156bb 213
rahul_dahiya 0:fb8047b156bb 214 socket.set_timeout(DNS_TIMEOUT);
rahul_dahiya 0:fb8047b156bb 215
rahul_dahiya 0:fb8047b156bb 216 // create network packet
rahul_dahiya 0:fb8047b156bb 217 uint8_t *packet = (uint8_t *)malloc(DNS_BUFFER_SIZE);
rahul_dahiya 0:fb8047b156bb 218 if (!packet) {
rahul_dahiya 0:fb8047b156bb 219 return NSAPI_ERROR_NO_MEMORY;
rahul_dahiya 0:fb8047b156bb 220 }
rahul_dahiya 0:fb8047b156bb 221
rahul_dahiya 0:fb8047b156bb 222 nsapi_size_or_error_t result = NSAPI_ERROR_DNS_FAILURE;
rahul_dahiya 0:fb8047b156bb 223
rahul_dahiya 0:fb8047b156bb 224 // check against each dns server
rahul_dahiya 0:fb8047b156bb 225 for (unsigned i = 0; i < DNS_SERVERS_SIZE; i++) {
rahul_dahiya 0:fb8047b156bb 226 // send the question
rahul_dahiya 0:fb8047b156bb 227 uint8_t *question = packet;
rahul_dahiya 0:fb8047b156bb 228 dns_append_question(&question, host, version);
rahul_dahiya 0:fb8047b156bb 229
rahul_dahiya 0:fb8047b156bb 230 err = socket.sendto(SocketAddress(dns_servers[i], 53), packet, question - packet);
rahul_dahiya 0:fb8047b156bb 231 // send may fail for various reasons, including wrong address type - move on
rahul_dahiya 0:fb8047b156bb 232 if (err < 0) {
rahul_dahiya 0:fb8047b156bb 233 continue;
rahul_dahiya 0:fb8047b156bb 234 }
rahul_dahiya 0:fb8047b156bb 235
rahul_dahiya 0:fb8047b156bb 236 // recv the response
rahul_dahiya 0:fb8047b156bb 237 err = socket.recvfrom(NULL, packet, DNS_BUFFER_SIZE);
rahul_dahiya 0:fb8047b156bb 238 if (err == NSAPI_ERROR_WOULD_BLOCK) {
rahul_dahiya 0:fb8047b156bb 239 continue;
rahul_dahiya 0:fb8047b156bb 240 } else if (err < 0) {
rahul_dahiya 0:fb8047b156bb 241 result = err;
rahul_dahiya 0:fb8047b156bb 242 break;
rahul_dahiya 0:fb8047b156bb 243 }
rahul_dahiya 0:fb8047b156bb 244
rahul_dahiya 0:fb8047b156bb 245 const uint8_t *response = packet;
rahul_dahiya 0:fb8047b156bb 246 if (dns_scan_response(&response, addr, addr_count) > 0) {
rahul_dahiya 0:fb8047b156bb 247 result = NSAPI_ERROR_OK;
rahul_dahiya 0:fb8047b156bb 248 }
rahul_dahiya 0:fb8047b156bb 249
rahul_dahiya 0:fb8047b156bb 250 /* The DNS response is final, no need to check other servers */
rahul_dahiya 0:fb8047b156bb 251 break;
rahul_dahiya 0:fb8047b156bb 252 }
rahul_dahiya 0:fb8047b156bb 253
rahul_dahiya 0:fb8047b156bb 254 // clean up packet
rahul_dahiya 0:fb8047b156bb 255 free(packet);
rahul_dahiya 0:fb8047b156bb 256
rahul_dahiya 0:fb8047b156bb 257 // clean up udp
rahul_dahiya 0:fb8047b156bb 258 err = socket.close();
rahul_dahiya 0:fb8047b156bb 259 if (err) {
rahul_dahiya 0:fb8047b156bb 260 return err;
rahul_dahiya 0:fb8047b156bb 261 }
rahul_dahiya 0:fb8047b156bb 262
rahul_dahiya 0:fb8047b156bb 263 // return result
rahul_dahiya 0:fb8047b156bb 264 return result;
rahul_dahiya 0:fb8047b156bb 265 }
rahul_dahiya 0:fb8047b156bb 266
rahul_dahiya 0:fb8047b156bb 267 // convenience functions for other forms of queries
rahul_dahiya 0:fb8047b156bb 268 extern "C" nsapi_size_or_error_t nsapi_dns_query_multiple(nsapi_stack_t *stack, const char *host,
rahul_dahiya 0:fb8047b156bb 269 nsapi_addr_t *addr, nsapi_size_t addr_count, nsapi_version_t version)
rahul_dahiya 0:fb8047b156bb 270 {
rahul_dahiya 0:fb8047b156bb 271 NetworkStack *nstack = nsapi_create_stack(stack);
rahul_dahiya 0:fb8047b156bb 272 return nsapi_dns_query_multiple(nstack, host, addr, addr_count, version);
rahul_dahiya 0:fb8047b156bb 273 }
rahul_dahiya 0:fb8047b156bb 274
rahul_dahiya 0:fb8047b156bb 275 nsapi_size_or_error_t nsapi_dns_query_multiple(NetworkStack *stack, const char *host,
rahul_dahiya 0:fb8047b156bb 276 SocketAddress *addresses, nsapi_size_t addr_count, nsapi_version_t version)
rahul_dahiya 0:fb8047b156bb 277 {
rahul_dahiya 0:fb8047b156bb 278 nsapi_addr_t *addrs = new nsapi_addr_t[addr_count];
rahul_dahiya 0:fb8047b156bb 279 nsapi_size_or_error_t result = nsapi_dns_query_multiple(stack, host, addrs, addr_count, version);
rahul_dahiya 0:fb8047b156bb 280
rahul_dahiya 0:fb8047b156bb 281 if (result > 0) {
rahul_dahiya 0:fb8047b156bb 282 for (int i = 0; i < result; i++) {
rahul_dahiya 0:fb8047b156bb 283 addresses[i].set_addr(addrs[i]);
rahul_dahiya 0:fb8047b156bb 284 }
rahul_dahiya 0:fb8047b156bb 285 }
rahul_dahiya 0:fb8047b156bb 286
rahul_dahiya 0:fb8047b156bb 287 delete[] addrs;
rahul_dahiya 0:fb8047b156bb 288 return result;
rahul_dahiya 0:fb8047b156bb 289 }
rahul_dahiya 0:fb8047b156bb 290
rahul_dahiya 0:fb8047b156bb 291 extern "C" nsapi_error_t nsapi_dns_query(nsapi_stack_t *stack, const char *host,
rahul_dahiya 0:fb8047b156bb 292 nsapi_addr_t *addr, nsapi_version_t version)
rahul_dahiya 0:fb8047b156bb 293 {
rahul_dahiya 0:fb8047b156bb 294 NetworkStack *nstack = nsapi_create_stack(stack);
rahul_dahiya 0:fb8047b156bb 295 nsapi_size_or_error_t result = nsapi_dns_query_multiple(nstack, host, addr, 1, version);
rahul_dahiya 0:fb8047b156bb 296 return (nsapi_error_t)((result > 0) ? 0 : result);
rahul_dahiya 0:fb8047b156bb 297 }
rahul_dahiya 0:fb8047b156bb 298
rahul_dahiya 0:fb8047b156bb 299 nsapi_error_t nsapi_dns_query(NetworkStack *stack, const char *host,
rahul_dahiya 0:fb8047b156bb 300 SocketAddress *address, nsapi_version_t version)
rahul_dahiya 0:fb8047b156bb 301 {
rahul_dahiya 0:fb8047b156bb 302 nsapi_addr_t addr;
rahul_dahiya 0:fb8047b156bb 303 nsapi_size_or_error_t result = nsapi_dns_query_multiple(stack, host, &addr, 1, version);
rahul_dahiya 0:fb8047b156bb 304 address->set_addr(addr);
rahul_dahiya 0:fb8047b156bb 305 return (nsapi_error_t)((result > 0) ? 0 : result);
rahul_dahiya 0:fb8047b156bb 306 }