ON Semiconductor / mbed-os

Dependents:   mbed-TFT-example-NCS36510 mbed-Accelerometer-example-NCS36510 mbed-Accelerometer-example-NCS36510

features/netsocket/nsapi_dns.cpp@0:098463de4c5d, 2017-01-25 (annotated)

Committer:
group-onsemi
Date:
Wed Jan 25 20:34:15 2017 +0000
Revision:
0:098463de4c5d
Initial commit

Who changed what in which revision?

UserRevisionLine numberNew contents of line
group-onsemi 0:098463de4c5d 1 /* nsapi_dns.cpp
group-onsemi 0:098463de4c5d 2 * Original work Copyright (c) 2013 Henry Leinen (henry[dot]leinen [at] online [dot] de)
group-onsemi 0:098463de4c5d 3 * Modified work Copyright (c) 2015 ARM Limited
group-onsemi 0:098463de4c5d 4 *
group-onsemi 0:098463de4c5d 5 * Licensed under the Apache License, Version 2.0 (the "License");
group-onsemi 0:098463de4c5d 6 * you may not use this file except in compliance with the License.
group-onsemi 0:098463de4c5d 7 * You may obtain a copy of the License at
group-onsemi 0:098463de4c5d 8 *
group-onsemi 0:098463de4c5d 9 * http://www.apache.org/licenses/LICENSE-2.0
group-onsemi 0:098463de4c5d 10 *
group-onsemi 0:098463de4c5d 11 * Unless required by applicable law or agreed to in writing, software
group-onsemi 0:098463de4c5d 12 * distributed under the License is distributed on an "AS IS" BASIS,
group-onsemi 0:098463de4c5d 13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
group-onsemi 0:098463de4c5d 14 * See the License for the specific language governing permissions and
group-onsemi 0:098463de4c5d 15 * limitations under the License.
group-onsemi 0:098463de4c5d 16 */
group-onsemi 0:098463de4c5d 17 #include "nsapi_dns.h"
group-onsemi 0:098463de4c5d 18 #include "netsocket/UDPSocket.h"
group-onsemi 0:098463de4c5d 19 #include <string.h>
group-onsemi 0:098463de4c5d 20 #include <stdlib.h>
group-onsemi 0:098463de4c5d 21 #include <stdio.h>
group-onsemi 0:098463de4c5d 22
group-onsemi 0:098463de4c5d 23 #define CLASS_IN 1
group-onsemi 0:098463de4c5d 24
group-onsemi 0:098463de4c5d 25 #define RR_A 1
group-onsemi 0:098463de4c5d 26 #define RR_AAAA 28
group-onsemi 0:098463de4c5d 27
group-onsemi 0:098463de4c5d 28 // DNS options
group-onsemi 0:098463de4c5d 29 #define DNS_BUFFER_SIZE 512
group-onsemi 0:098463de4c5d 30 #define DNS_TIMEOUT 5000
group-onsemi 0:098463de4c5d 31 #define DNS_SERVERS_SIZE 5
group-onsemi 0:098463de4c5d 32
group-onsemi 0:098463de4c5d 33 nsapi_addr_t dns_servers[DNS_SERVERS_SIZE] = {
group-onsemi 0:098463de4c5d 34 {NSAPI_IPv4, {8, 8, 8, 8}}, // Google
group-onsemi 0:098463de4c5d 35 {NSAPI_IPv4, {209, 244, 0, 3}}, // Level 3
group-onsemi 0:098463de4c5d 36 {NSAPI_IPv4, {84, 200, 69, 80}}, // DNS.WATCH
group-onsemi 0:098463de4c5d 37 {NSAPI_IPv6, {0x20,0x01, 0x48,0x60, 0x48,0x60, 0,0, // Google
group-onsemi 0:098463de4c5d 38 0,0, 0,0, 0,0, 0x88,0x88}},
group-onsemi 0:098463de4c5d 39 {NSAPI_IPv6, {0x20,0x01, 0x16,0x08, 0,0x10, 0,0x25, // DNS.WATCH
group-onsemi 0:098463de4c5d 40 0,0, 0,0, 0x1c,0x04, 0xb1,0x2f}},
group-onsemi 0:098463de4c5d 41 };
group-onsemi 0:098463de4c5d 42
group-onsemi 0:098463de4c5d 43 // DNS server configuration
group-onsemi 0:098463de4c5d 44 extern "C" nsapi_error_t nsapi_dns_add_server(nsapi_addr_t addr)
group-onsemi 0:098463de4c5d 45 {
group-onsemi 0:098463de4c5d 46 memmove(&dns_servers[1], &dns_servers[0],
group-onsemi 0:098463de4c5d 47 (DNS_SERVERS_SIZE-1)*sizeof(nsapi_addr_t));
group-onsemi 0:098463de4c5d 48
group-onsemi 0:098463de4c5d 49 dns_servers[0] = addr;
group-onsemi 0:098463de4c5d 50 return NSAPI_ERROR_OK;
group-onsemi 0:098463de4c5d 51 }
group-onsemi 0:098463de4c5d 52
group-onsemi 0:098463de4c5d 53
group-onsemi 0:098463de4c5d 54 // DNS packet parsing
group-onsemi 0:098463de4c5d 55 static void dns_append_byte(uint8_t **p, uint8_t byte)
group-onsemi 0:098463de4c5d 56 {
group-onsemi 0:098463de4c5d 57 *(*p)++ = byte;
group-onsemi 0:098463de4c5d 58 }
group-onsemi 0:098463de4c5d 59
group-onsemi 0:098463de4c5d 60 static void dns_append_word(uint8_t **p, uint16_t word)
group-onsemi 0:098463de4c5d 61 {
group-onsemi 0:098463de4c5d 62
group-onsemi 0:098463de4c5d 63 dns_append_byte(p, 0xff & (word >> 8));
group-onsemi 0:098463de4c5d 64 dns_append_byte(p, 0xff & (word >> 0));
group-onsemi 0:098463de4c5d 65 }
group-onsemi 0:098463de4c5d 66
group-onsemi 0:098463de4c5d 67 static void dns_append_name(uint8_t **p, const char *name, uint8_t len)
group-onsemi 0:098463de4c5d 68 {
group-onsemi 0:098463de4c5d 69 dns_append_byte(p, len);
group-onsemi 0:098463de4c5d 70 memcpy(*p, name, len);
group-onsemi 0:098463de4c5d 71 *p += len;
group-onsemi 0:098463de4c5d 72 }
group-onsemi 0:098463de4c5d 73
group-onsemi 0:098463de4c5d 74 static uint8_t dns_scan_byte(const uint8_t **p)
group-onsemi 0:098463de4c5d 75 {
group-onsemi 0:098463de4c5d 76 return *(*p)++;
group-onsemi 0:098463de4c5d 77 }
group-onsemi 0:098463de4c5d 78
group-onsemi 0:098463de4c5d 79 static uint16_t dns_scan_word(const uint8_t **p)
group-onsemi 0:098463de4c5d 80 {
group-onsemi 0:098463de4c5d 81 uint16_t a = dns_scan_byte(p);
group-onsemi 0:098463de4c5d 82 uint16_t b = dns_scan_byte(p);
group-onsemi 0:098463de4c5d 83 return (a << 8) | b;
group-onsemi 0:098463de4c5d 84 }
group-onsemi 0:098463de4c5d 85
group-onsemi 0:098463de4c5d 86
group-onsemi 0:098463de4c5d 87 static void dns_append_question(uint8_t **p, const char *host, nsapi_version_t version)
group-onsemi 0:098463de4c5d 88 {
group-onsemi 0:098463de4c5d 89 // fill the header
group-onsemi 0:098463de4c5d 90 dns_append_word(p, 1); // id = 1
group-onsemi 0:098463de4c5d 91 dns_append_word(p, 0x0100); // flags = recursion required
group-onsemi 0:098463de4c5d 92 dns_append_word(p, 1); // qdcount = 1
group-onsemi 0:098463de4c5d 93 dns_append_word(p, 0); // ancount = 0
group-onsemi 0:098463de4c5d 94 dns_append_word(p, 0); // nscount = 0
group-onsemi 0:098463de4c5d 95 dns_append_word(p, 0); // arcount = 0
group-onsemi 0:098463de4c5d 96
group-onsemi 0:098463de4c5d 97 // fill out the question names
group-onsemi 0:098463de4c5d 98 while (host[0]) {
group-onsemi 0:098463de4c5d 99 size_t label_len = strcspn(host, ".");
group-onsemi 0:098463de4c5d 100 dns_append_name(p, host, label_len);
group-onsemi 0:098463de4c5d 101 host += label_len + (host[label_len] == '.');
group-onsemi 0:098463de4c5d 102 }
group-onsemi 0:098463de4c5d 103
group-onsemi 0:098463de4c5d 104 dns_append_byte(p, 0);
group-onsemi 0:098463de4c5d 105
group-onsemi 0:098463de4c5d 106 // fill out question footer
group-onsemi 0:098463de4c5d 107 if (version != NSAPI_IPv6) {
group-onsemi 0:098463de4c5d 108 dns_append_word(p, RR_A); // qtype = ipv4
group-onsemi 0:098463de4c5d 109 } else {
group-onsemi 0:098463de4c5d 110 dns_append_word(p, RR_AAAA); // qtype = ipv6
group-onsemi 0:098463de4c5d 111 }
group-onsemi 0:098463de4c5d 112 dns_append_word(p, CLASS_IN);
group-onsemi 0:098463de4c5d 113 }
group-onsemi 0:098463de4c5d 114
group-onsemi 0:098463de4c5d 115 static int dns_scan_response(const uint8_t **p, nsapi_addr_t *addr, unsigned addr_count)
group-onsemi 0:098463de4c5d 116 {
group-onsemi 0:098463de4c5d 117 // scan header
group-onsemi 0:098463de4c5d 118 uint16_t id = dns_scan_word(p);
group-onsemi 0:098463de4c5d 119 uint16_t flags = dns_scan_word(p);
group-onsemi 0:098463de4c5d 120 bool qr = 0x1 & (flags >> 15);
group-onsemi 0:098463de4c5d 121 uint8_t opcode = 0xf & (flags >> 11);
group-onsemi 0:098463de4c5d 122 uint8_t rcode = 0xf & (flags >> 0);
group-onsemi 0:098463de4c5d 123
group-onsemi 0:098463de4c5d 124 uint16_t qdcount = dns_scan_word(p); // qdcount
group-onsemi 0:098463de4c5d 125 uint16_t ancount = dns_scan_word(p); // ancount
group-onsemi 0:098463de4c5d 126 dns_scan_word(p); // nscount
group-onsemi 0:098463de4c5d 127 dns_scan_word(p); // arcount
group-onsemi 0:098463de4c5d 128
group-onsemi 0:098463de4c5d 129 // verify header is response to query
group-onsemi 0:098463de4c5d 130 if (!(id == 1 && qr && opcode == 0 && rcode == 0)) {
group-onsemi 0:098463de4c5d 131 return 0;
group-onsemi 0:098463de4c5d 132 }
group-onsemi 0:098463de4c5d 133
group-onsemi 0:098463de4c5d 134 // skip questions
group-onsemi 0:098463de4c5d 135 for (int i = 0; i < qdcount; i++) {
group-onsemi 0:098463de4c5d 136 while (true) {
group-onsemi 0:098463de4c5d 137 uint8_t len = dns_scan_byte(p);
group-onsemi 0:098463de4c5d 138 if (len == 0) {
group-onsemi 0:098463de4c5d 139 break;
group-onsemi 0:098463de4c5d 140 }
group-onsemi 0:098463de4c5d 141
group-onsemi 0:098463de4c5d 142 *p += len;
group-onsemi 0:098463de4c5d 143 }
group-onsemi 0:098463de4c5d 144
group-onsemi 0:098463de4c5d 145 dns_scan_word(p); // qtype
group-onsemi 0:098463de4c5d 146 dns_scan_word(p); // qclass
group-onsemi 0:098463de4c5d 147 }
group-onsemi 0:098463de4c5d 148
group-onsemi 0:098463de4c5d 149 // scan each response
group-onsemi 0:098463de4c5d 150 unsigned count = 0;
group-onsemi 0:098463de4c5d 151
group-onsemi 0:098463de4c5d 152 for (int i = 0; i < ancount && count < addr_count; i++) {
group-onsemi 0:098463de4c5d 153 while (true) {
group-onsemi 0:098463de4c5d 154 uint8_t len = dns_scan_byte(p);
group-onsemi 0:098463de4c5d 155 if (len == 0) {
group-onsemi 0:098463de4c5d 156 break;
group-onsemi 0:098463de4c5d 157 } else if (len & 0xc0) { // this is link
group-onsemi 0:098463de4c5d 158 dns_scan_byte(p);
group-onsemi 0:098463de4c5d 159 break;
group-onsemi 0:098463de4c5d 160 }
group-onsemi 0:098463de4c5d 161
group-onsemi 0:098463de4c5d 162 *p += len;
group-onsemi 0:098463de4c5d 163 }
group-onsemi 0:098463de4c5d 164
group-onsemi 0:098463de4c5d 165 uint16_t rtype = dns_scan_word(p); // rtype
group-onsemi 0:098463de4c5d 166 uint16_t rclass = dns_scan_word(p); // rclass
group-onsemi 0:098463de4c5d 167 *p += 4; // ttl
group-onsemi 0:098463de4c5d 168 uint16_t rdlength = dns_scan_word(p); // rdlength
group-onsemi 0:098463de4c5d 169
group-onsemi 0:098463de4c5d 170 if (rtype == RR_A && rclass == CLASS_IN && rdlength == NSAPI_IPv4_BYTES) {
group-onsemi 0:098463de4c5d 171 // accept A record
group-onsemi 0:098463de4c5d 172 addr->version = NSAPI_IPv4;
group-onsemi 0:098463de4c5d 173 for (int i = 0; i < NSAPI_IPv4_BYTES; i++) {
group-onsemi 0:098463de4c5d 174 addr->bytes[i] = dns_scan_byte(p);
group-onsemi 0:098463de4c5d 175 }
group-onsemi 0:098463de4c5d 176
group-onsemi 0:098463de4c5d 177 addr += 1;
group-onsemi 0:098463de4c5d 178 count += 1;
group-onsemi 0:098463de4c5d 179 } else if (rtype == RR_AAAA && rclass == CLASS_IN && rdlength == NSAPI_IPv6_BYTES) {
group-onsemi 0:098463de4c5d 180 // accept AAAA record
group-onsemi 0:098463de4c5d 181 addr->version = NSAPI_IPv6;
group-onsemi 0:098463de4c5d 182 for (int i = 0; i < NSAPI_IPv6_BYTES; i++) {
group-onsemi 0:098463de4c5d 183 addr->bytes[i] = dns_scan_byte(p);
group-onsemi 0:098463de4c5d 184 }
group-onsemi 0:098463de4c5d 185
group-onsemi 0:098463de4c5d 186 addr += 1;
group-onsemi 0:098463de4c5d 187 count += 1;
group-onsemi 0:098463de4c5d 188 } else {
group-onsemi 0:098463de4c5d 189 // skip unrecognized records
group-onsemi 0:098463de4c5d 190 *p += rdlength;
group-onsemi 0:098463de4c5d 191 }
group-onsemi 0:098463de4c5d 192 }
group-onsemi 0:098463de4c5d 193
group-onsemi 0:098463de4c5d 194 return count;
group-onsemi 0:098463de4c5d 195 }
group-onsemi 0:098463de4c5d 196
group-onsemi 0:098463de4c5d 197 // core query function
group-onsemi 0:098463de4c5d 198 static nsapi_size_or_error_t nsapi_dns_query_multiple(NetworkStack *stack, const char *host,
group-onsemi 0:098463de4c5d 199 nsapi_addr_t *addr, unsigned addr_count, nsapi_version_t version)
group-onsemi 0:098463de4c5d 200 {
group-onsemi 0:098463de4c5d 201 // check for valid host name
group-onsemi 0:098463de4c5d 202 int host_len = host ? strlen(host) : 0;
group-onsemi 0:098463de4c5d 203 if (host_len > 128 || host_len == 0) {
group-onsemi 0:098463de4c5d 204 return NSAPI_ERROR_PARAMETER;
group-onsemi 0:098463de4c5d 205 }
group-onsemi 0:098463de4c5d 206
group-onsemi 0:098463de4c5d 207 // create a udp socket
group-onsemi 0:098463de4c5d 208 UDPSocket socket;
group-onsemi 0:098463de4c5d 209 int err = socket.open(stack);
group-onsemi 0:098463de4c5d 210 if (err) {
group-onsemi 0:098463de4c5d 211 return err;
group-onsemi 0:098463de4c5d 212 }
group-onsemi 0:098463de4c5d 213
group-onsemi 0:098463de4c5d 214 socket.set_timeout(DNS_TIMEOUT);
group-onsemi 0:098463de4c5d 215
group-onsemi 0:098463de4c5d 216 // create network packet
group-onsemi 0:098463de4c5d 217 uint8_t *packet = (uint8_t *)malloc(DNS_BUFFER_SIZE);
group-onsemi 0:098463de4c5d 218 if (!packet) {
group-onsemi 0:098463de4c5d 219 return NSAPI_ERROR_NO_MEMORY;
group-onsemi 0:098463de4c5d 220 }
group-onsemi 0:098463de4c5d 221
group-onsemi 0:098463de4c5d 222 nsapi_size_or_error_t result = NSAPI_ERROR_DNS_FAILURE;
group-onsemi 0:098463de4c5d 223
group-onsemi 0:098463de4c5d 224 // check against each dns server
group-onsemi 0:098463de4c5d 225 for (unsigned i = 0; i < DNS_SERVERS_SIZE; i++) {
group-onsemi 0:098463de4c5d 226 // send the question
group-onsemi 0:098463de4c5d 227 uint8_t *question = packet;
group-onsemi 0:098463de4c5d 228 dns_append_question(&question, host, version);
group-onsemi 0:098463de4c5d 229
group-onsemi 0:098463de4c5d 230 err = socket.sendto(SocketAddress(dns_servers[i], 53), packet, DNS_BUFFER_SIZE);
group-onsemi 0:098463de4c5d 231 // send may fail for various reasons, including wrong address type - move on
group-onsemi 0:098463de4c5d 232 if (err < 0) {
group-onsemi 0:098463de4c5d 233 continue;
group-onsemi 0:098463de4c5d 234 }
group-onsemi 0:098463de4c5d 235
group-onsemi 0:098463de4c5d 236 // recv the response
group-onsemi 0:098463de4c5d 237 err = socket.recvfrom(NULL, packet, DNS_BUFFER_SIZE);
group-onsemi 0:098463de4c5d 238 if (err == NSAPI_ERROR_WOULD_BLOCK) {
group-onsemi 0:098463de4c5d 239 continue;
group-onsemi 0:098463de4c5d 240 } else if (err < 0) {
group-onsemi 0:098463de4c5d 241 result = err;
group-onsemi 0:098463de4c5d 242 break;
group-onsemi 0:098463de4c5d 243 }
group-onsemi 0:098463de4c5d 244
group-onsemi 0:098463de4c5d 245 const uint8_t *response = packet;
group-onsemi 0:098463de4c5d 246 if (dns_scan_response(&response, addr, addr_count) > 0) {
group-onsemi 0:098463de4c5d 247 result = NSAPI_ERROR_OK;
group-onsemi 0:098463de4c5d 248 }
group-onsemi 0:098463de4c5d 249
group-onsemi 0:098463de4c5d 250 /* The DNS response is final, no need to check other servers */
group-onsemi 0:098463de4c5d 251 break;
group-onsemi 0:098463de4c5d 252 }
group-onsemi 0:098463de4c5d 253
group-onsemi 0:098463de4c5d 254 // clean up packet
group-onsemi 0:098463de4c5d 255 free(packet);
group-onsemi 0:098463de4c5d 256
group-onsemi 0:098463de4c5d 257 // clean up udp
group-onsemi 0:098463de4c5d 258 err = socket.close();
group-onsemi 0:098463de4c5d 259 if (err) {
group-onsemi 0:098463de4c5d 260 return err;
group-onsemi 0:098463de4c5d 261 }
group-onsemi 0:098463de4c5d 262
group-onsemi 0:098463de4c5d 263 // return result
group-onsemi 0:098463de4c5d 264 return result;
group-onsemi 0:098463de4c5d 265 }
group-onsemi 0:098463de4c5d 266
group-onsemi 0:098463de4c5d 267 // convenience functions for other forms of queries
group-onsemi 0:098463de4c5d 268 extern "C" nsapi_size_or_error_t nsapi_dns_query_multiple(nsapi_stack_t *stack, const char *host,
group-onsemi 0:098463de4c5d 269 nsapi_addr_t *addr, nsapi_size_t addr_count, nsapi_version_t version)
group-onsemi 0:098463de4c5d 270 {
group-onsemi 0:098463de4c5d 271 NetworkStack *nstack = nsapi_create_stack(stack);
group-onsemi 0:098463de4c5d 272 return nsapi_dns_query_multiple(nstack, host, addr, addr_count, version);
group-onsemi 0:098463de4c5d 273 }
group-onsemi 0:098463de4c5d 274
group-onsemi 0:098463de4c5d 275 nsapi_size_or_error_t nsapi_dns_query_multiple(NetworkStack *stack, const char *host,
group-onsemi 0:098463de4c5d 276 SocketAddress *addresses, nsapi_size_t addr_count, nsapi_version_t version)
group-onsemi 0:098463de4c5d 277 {
group-onsemi 0:098463de4c5d 278 nsapi_addr_t *addrs = new nsapi_addr_t[addr_count];
group-onsemi 0:098463de4c5d 279 nsapi_size_or_error_t result = nsapi_dns_query_multiple(stack, host, addrs, addr_count, version);
group-onsemi 0:098463de4c5d 280
group-onsemi 0:098463de4c5d 281 if (result > 0) {
group-onsemi 0:098463de4c5d 282 for (int i = 0; i < result; i++) {
group-onsemi 0:098463de4c5d 283 addresses[i].set_addr(addrs[i]);
group-onsemi 0:098463de4c5d 284 }
group-onsemi 0:098463de4c5d 285 }
group-onsemi 0:098463de4c5d 286
group-onsemi 0:098463de4c5d 287 delete[] addrs;
group-onsemi 0:098463de4c5d 288 return result;
group-onsemi 0:098463de4c5d 289 }
group-onsemi 0:098463de4c5d 290
group-onsemi 0:098463de4c5d 291 extern "C" nsapi_error_t nsapi_dns_query(nsapi_stack_t *stack, const char *host,
group-onsemi 0:098463de4c5d 292 nsapi_addr_t *addr, nsapi_version_t version)
group-onsemi 0:098463de4c5d 293 {
group-onsemi 0:098463de4c5d 294 NetworkStack *nstack = nsapi_create_stack(stack);
group-onsemi 0:098463de4c5d 295 nsapi_size_or_error_t result = nsapi_dns_query_multiple(nstack, host, addr, 1, version);
group-onsemi 0:098463de4c5d 296 return (nsapi_error_t)((result > 0) ? 0 : result);
group-onsemi 0:098463de4c5d 297 }
group-onsemi 0:098463de4c5d 298
group-onsemi 0:098463de4c5d 299 nsapi_error_t nsapi_dns_query(NetworkStack *stack, const char *host,
group-onsemi 0:098463de4c5d 300 SocketAddress *address, nsapi_version_t version)
group-onsemi 0:098463de4c5d 301 {
group-onsemi 0:098463de4c5d 302 nsapi_addr_t addr;
group-onsemi 0:098463de4c5d 303 nsapi_size_or_error_t result = nsapi_dns_query_multiple(stack, host, &addr, 1, version);
group-onsemi 0:098463de4c5d 304 address->set_addr(addr);
group-onsemi 0:098463de4c5d 305 return (nsapi_error_t)((result > 0) ? 0 : result);
group-onsemi 0:098463de4c5d 306 }