Takehisa Oneta / DnsQuery

modified by ohneta

Dependents:   HelloESP8266Interface_mine

Fork of DnsQuery by Sarah Marsh

DnsQuery.cpp@5:7555d509b568, 2015-11-11 (annotated)

Committer:
ohneta
Date:
Wed Nov 11 03:39:26 2015 +0000
Revision:
5:7555d509b568
Parent:
4:7e64d099f63e 
added timeout=1000ms on "Receive the answer from DNS?

Who changed what in which revision?

UserRevisionLine numberNew contents of line
sarahmarshy 0:fff4b9055396 1 /* Copyright (c) 2013 Henry Leinen (henry[dot]leinen [at] online [dot] de)
sarahmarshy 0:fff4b9055396 2 *
sarahmarshy 0:fff4b9055396 3 * Permission is hereby granted, free of charge, to any person obtaining a copy of this software
sarahmarshy 0:fff4b9055396 4 * and associated documentation files (the "Software"), to deal in the Software without restriction,
sarahmarshy 0:fff4b9055396 5 * including without limitation the rights to use, copy, modify, merge, publish, distribute,
sarahmarshy 0:fff4b9055396 6 * sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is
sarahmarshy 0:fff4b9055396 7 * furnished to do so, subject to the following conditions:
sarahmarshy 0:fff4b9055396 8 *
sarahmarshy 0:fff4b9055396 9 * The above copyright notice and this permission notice shall be included in all copies or
sarahmarshy 0:fff4b9055396 10 * substantial portions of the Software.
sarahmarshy 0:fff4b9055396 11 *
sarahmarshy 0:fff4b9055396 12 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING
sarahmarshy 0:fff4b9055396 13 * BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
sarahmarshy 0:fff4b9055396 14 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
sarahmarshy 0:fff4b9055396 15 * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
sarahmarshy 0:fff4b9055396 16 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
sarahmarshy 0:fff4b9055396 17 */
sarahmarshy 0:fff4b9055396 18 #include "mbed.h"
sarahmarshy 0:fff4b9055396 19 #include "DnsQuery.h"
sarahmarshy 0:fff4b9055396 20
sarahmarshy 0:fff4b9055396 21 //Debug is disabled by default
sarahmarshy 0:fff4b9055396 22 #if 0
sarahmarshy 0:fff4b9055396 23 #define DBG(x, ...) printf("[DNS : DBG]"x" \t[%s,%d]\r\n", ##__VA_ARGS__,__FILE__,__LINE__);
sarahmarshy 0:fff4b9055396 24 #define WARN(x, ...) printf("[DNS : WARN]"x" \t[%s,%d]\r\n", ##__VA_ARGS__,__FILE__,__LINE__);
sarahmarshy 0:fff4b9055396 25 #define ERR(x, ...) printf("[DNS : ERR]"x" \t[%s,%d]\r\n", ##__VA_ARGS__,__FILE__,__LINE__);
sarahmarshy 0:fff4b9055396 26 #else
sarahmarshy 0:fff4b9055396 27 #define DBG(x, ...) //wait_us(10);
sarahmarshy 0:fff4b9055396 28 #define WARN(x, ...) //wait_us(10);
sarahmarshy 0:fff4b9055396 29 #define ERR(x, ...)
sarahmarshy 0:fff4b9055396 30 #endif
sarahmarshy 0:fff4b9055396 31
sarahmarshy 0:fff4b9055396 32 #if 0
sarahmarshy 0:fff4b9055396 33 #define INFO(x, ...) printf("[DNS : INFO]"x" \t[%s,%d]\r\n", ##__VA_ARGS__,__FILE__,__LINE__);
sarahmarshy 0:fff4b9055396 34 #else
sarahmarshy 0:fff4b9055396 35 #define INFO(x, ...)
sarahmarshy 0:fff4b9055396 36 #endif
sarahmarshy 0:fff4b9055396 37
sarahmarshy 0:fff4b9055396 38
sarahmarshy 0:fff4b9055396 39
ohneta 5:7555d509b568 40
ohneta 5:7555d509b568 41 DnsQuery::DnsQuery(SocketInterface *sock, const char* hostname, char* ipaddress, const char *preferreddnsIp)
sarahmarshy 0:fff4b9055396 42 {
sarahmarshy 1:5d978992a518 43 socket = sock;
ohneta 5:7555d509b568 44 this->setPreferredDNSServerIP(preferreddnsIp);
sarahmarshy 3:5705fdae6185 45 this->getHostByName(hostname, ipaddress);
sarahmarshy 0:fff4b9055396 46 }
sarahmarshy 0:fff4b9055396 47
ohneta 5:7555d509b568 48 void DnsQuery::setPreferredDNSServerIP(const char *preferreddnsIp)
ohneta 4:7e64d099f63e 49 {
ohneta 5:7555d509b568 50 _preferred_dnsip = preferreddnsIp;
ohneta 4:7e64d099f63e 51 }
ohneta 4:7e64d099f63e 52
sarahmarshy 3:5705fdae6185 53 bool DnsQuery::getHostByName(const char* hostname, char* resolvedIp)
sarahmarshy 0:fff4b9055396 54 {
ohneta 4:7e64d099f63e 55 if (_preferred_dnsip != NULL) {
ohneta 4:7e64d099f63e 56 _dnsip = (char *)_preferred_dnsip;
ohneta 4:7e64d099f63e 57 if (this->getIP(hostname, resolvedIp)) {
ohneta 4:7e64d099f63e 58 return true;
ohneta 4:7e64d099f63e 59 }
ohneta 4:7e64d099f63e 60 }
ohneta 4:7e64d099f63e 61
sarahmarshy 2:12d08f0f20cf 62 char * dnsIPs[] = {
sarahmarshy 2:12d08f0f20cf 63 "8.8.8.8",
sarahmarshy 2:12d08f0f20cf 64 "209.244.0.3",
sarahmarshy 2:12d08f0f20cf 65 "84.200.69.80",
sarahmarshy 2:12d08f0f20cf 66 "8.26.56.26",
sarahmarshy 2:12d08f0f20cf 67 "208.67.222.222"
sarahmarshy 2:12d08f0f20cf 68 };
sarahmarshy 0:fff4b9055396 69 for(int i = 0; i<5; i++){
sarahmarshy 2:12d08f0f20cf 70 _dnsip = dnsIPs[i];
sarahmarshy 2:12d08f0f20cf 71 if(this->getIP(hostname, resolvedIp)){
sarahmarshy 0:fff4b9055396 72 return true;
sarahmarshy 0:fff4b9055396 73 }
sarahmarshy 0:fff4b9055396 74
sarahmarshy 0:fff4b9055396 75 }
sarahmarshy 0:fff4b9055396 76 return false;
sarahmarshy 0:fff4b9055396 77
sarahmarshy 0:fff4b9055396 78 }
sarahmarshy 0:fff4b9055396 79
sarahmarshy 2:12d08f0f20cf 80 bool DnsQuery::getIP(const char* hostname, char* ipaddress)
sarahmarshy 0:fff4b9055396 81 {
sarahmarshy 0:fff4b9055396 82 INFO("%s", hostname);
sarahmarshy 0:fff4b9055396 83 int len = 0;
sarahmarshy 0:fff4b9055396 84 if (hostname == NULL)
sarahmarshy 0:fff4b9055396 85 return false;
sarahmarshy 0:fff4b9055396 86 len = strlen(hostname);
sarahmarshy 0:fff4b9055396 87 if ((len >128) || (len == 0))
sarahmarshy 0:fff4b9055396 88 return false;
sarahmarshy 0:fff4b9055396 89
sarahmarshy 0:fff4b9055396 90 int packetlen = /* size of HEADER structure */ 12 + /* size of QUESTION Structure */5 + len + 1;
sarahmarshy 0:fff4b9055396 91 char *packet = new char[packetlen]; /* this is the UDP packet to send to the DNS */
sarahmarshy 0:fff4b9055396 92 if (packet == NULL)
sarahmarshy 0:fff4b9055396 93 return false;
sarahmarshy 0:fff4b9055396 94
sarahmarshy 0:fff4b9055396 95 // Fill the header
sarahmarshy 0:fff4b9055396 96 memset(packet, 0, packetlen);
sarahmarshy 0:fff4b9055396 97 packet[1] = 1; // ID = 1
sarahmarshy 0:fff4b9055396 98 packet[5] = 1; // QDCOUNT = 1 (contains one question)
sarahmarshy 0:fff4b9055396 99 packet[2] = 1; // recursion requested
sarahmarshy 0:fff4b9055396 100
sarahmarshy 0:fff4b9055396 101 int c = 13; // point to NAME element in question section or request
sarahmarshy 0:fff4b9055396 102 int cnt = 12; // points to the counter of
sarahmarshy 0:fff4b9055396 103 packet[cnt] = 0;
sarahmarshy 0:fff4b9055396 104 for (int i = 0 ; i < len ; i++) {
sarahmarshy 0:fff4b9055396 105 if (hostname[i] != '.') {
sarahmarshy 0:fff4b9055396 106 // Copy the character and increment the character counter
sarahmarshy 0:fff4b9055396 107 packet[cnt]++;
sarahmarshy 0:fff4b9055396 108 packet[c++] = hostname[i];
sarahmarshy 0:fff4b9055396 109 } else {
sarahmarshy 0:fff4b9055396 110 // Finished with this part, so go to the next
sarahmarshy 0:fff4b9055396 111 cnt = c++;
sarahmarshy 0:fff4b9055396 112 packet[cnt] = 0;
sarahmarshy 0:fff4b9055396 113 }
sarahmarshy 0:fff4b9055396 114 }
sarahmarshy 0:fff4b9055396 115
sarahmarshy 0:fff4b9055396 116 // Terminate this domain name with a zero entry
sarahmarshy 0:fff4b9055396 117 packet[c++] = 0;
sarahmarshy 0:fff4b9055396 118
sarahmarshy 0:fff4b9055396 119 // Set QTYPE
sarahmarshy 0:fff4b9055396 120 packet[c++] = 0;
sarahmarshy 0:fff4b9055396 121 packet[c++] = 1;
sarahmarshy 0:fff4b9055396 122 // Set QCLASS
sarahmarshy 0:fff4b9055396 123 packet[c++] = 0;
sarahmarshy 0:fff4b9055396 124 packet[c++] = 1;
sarahmarshy 0:fff4b9055396 125
sarahmarshy 0:fff4b9055396 126
sarahmarshy 0:fff4b9055396 127 // Ready to send to DNS
sarahmarshy 2:12d08f0f20cf 128 socket->setAddressPort(_dnsip, 53);
sarahmarshy 1:5d978992a518 129 socket->open();
sarahmarshy 0:fff4b9055396 130
sarahmarshy 1:5d978992a518 131 INFO("Sending packet of length %d",packetlen);
sarahmarshy 1:5d978992a518 132 /*
sarahmarshy 1:5d978992a518 133 for( int i = 0 ; i < c ; i++) {
sarahmarshy 1:5d978992a518 134 printf("%02x ", packet[i]);
sarahmarshy 1:5d978992a518 135 }
sarahmarshy 1:5d978992a518 136 */
sarahmarshy 1:5d978992a518 137 if (socket->send(packet, packetlen) < 0) {
sarahmarshy 0:fff4b9055396 138 delete packet;
sarahmarshy 0:fff4b9055396 139 return false;
sarahmarshy 0:fff4b9055396 140 }
sarahmarshy 0:fff4b9055396 141 delete packet;
sarahmarshy 0:fff4b9055396 142
sarahmarshy 0:fff4b9055396 143 packet = new char [1024];
sarahmarshy 0:fff4b9055396 144
sarahmarshy 0:fff4b9055396 145 // Receive the answer from DNS
sarahmarshy 0:fff4b9055396 146 int response_length = 0;
sarahmarshy 2:12d08f0f20cf 147 INFO("Recieving");
ohneta 5:7555d509b568 148 response_length = socket->recv(packet, 1024, 1000); // todo !!
sarahmarshy 1:5d978992a518 149 /*
sarahmarshy 1:5d978992a518 150 for( int i = 0 ; i < 1024; i++) {
sarahmarshy 1:5d978992a518 151 printf("%02x ", packet[i]);
sarahmarshy 1:5d978992a518 152 }
sarahmarshy 1:5d978992a518 153 */
sarahmarshy 2:12d08f0f20cf 154 if (response_length > 0 ) {
sarahmarshy 2:12d08f0f20cf 155 if (!resolve(packet, ipaddress)) {
sarahmarshy 2:12d08f0f20cf 156 socket->close();
sarahmarshy 0:fff4b9055396 157 delete packet;
sarahmarshy 2:12d08f0f20cf 158 ERR("NO IP FOUND\n");
sarahmarshy 2:12d08f0f20cf 159 return false;
sarahmarshy 0:fff4b9055396 160 }
sarahmarshy 2:12d08f0f20cf 161
sarahmarshy 2:12d08f0f20cf 162 // cleanup and return
sarahmarshy 2:12d08f0f20cf 163 delete packet;
sarahmarshy 2:12d08f0f20cf 164 socket->close();
sarahmarshy 2:12d08f0f20cf 165 return true;
sarahmarshy 2:12d08f0f20cf 166 } else {
sarahmarshy 2:12d08f0f20cf 167 ERR("SocketRecvFrom returned %d !", response_length);
sarahmarshy 2:12d08f0f20cf 168 }
sarahmarshy 1:5d978992a518 169 socket->close();
sarahmarshy 0:fff4b9055396 170 delete packet;
sarahmarshy 0:fff4b9055396 171 ERR("NO IP FOUND\n");
sarahmarshy 0:fff4b9055396 172 return false;
sarahmarshy 0:fff4b9055396 173 }
sarahmarshy 0:fff4b9055396 174
sarahmarshy 0:fff4b9055396 175
sarahmarshy 2:12d08f0f20cf 176 bool DnsQuery::resolve(char* resp, char* ipaddress)
sarahmarshy 0:fff4b9055396 177 {
sarahmarshy 0:fff4b9055396 178
sarahmarshy 0:fff4b9055396 179 int ID = (((int)resp[0]) <<8) + resp[1];
sarahmarshy 0:fff4b9055396 180 int QR = resp[2] >>7;
sarahmarshy 0:fff4b9055396 181 int Opcode = (resp[2]>>3) & 0x0F;
sarahmarshy 0:fff4b9055396 182 int RCODE = (resp[3] & 0x0F);
sarahmarshy 0:fff4b9055396 183 int ANCOUNT = (((int)resp[6])<<8)+ resp[7];
sarahmarshy 0:fff4b9055396 184
sarahmarshy 0:fff4b9055396 185 INFO("Resolving response : ID = %d, QR = %d, Opcode = %d, RCODE = %d", ID, QR, Opcode, RCODE);
sarahmarshy 0:fff4b9055396 186 if ((ID != 1) || (QR != 1) || (Opcode != 0) || (RCODE != 0)) {
sarahmarshy 0:fff4b9055396 187 ERR("Received non matching response from DNS !");
sarahmarshy 0:fff4b9055396 188 return false;
sarahmarshy 0:fff4b9055396 189 }
sarahmarshy 0:fff4b9055396 190
sarahmarshy 0:fff4b9055396 191 int c = 12;
sarahmarshy 0:fff4b9055396 192 int d;
sarahmarshy 0:fff4b9055396 193 // Skip domain question
sarahmarshy 0:fff4b9055396 194 while( (d=resp[c++]) != 0) {
sarahmarshy 0:fff4b9055396 195 c+=d;
sarahmarshy 0:fff4b9055396 196 }
sarahmarshy 0:fff4b9055396 197 c+= 4; // skip QTYPE and QCLASS
sarahmarshy 0:fff4b9055396 198
sarahmarshy 0:fff4b9055396 199 // Here comes the resource record
sarahmarshy 0:fff4b9055396 200 for (int ans = 0 ; ans < ANCOUNT; ans++) {
sarahmarshy 0:fff4b9055396 201 if (parseRR(resp, c, ipaddress)) {
sarahmarshy 0:fff4b9055396 202 return true;
sarahmarshy 0:fff4b9055396 203 }
sarahmarshy 0:fff4b9055396 204 }
sarahmarshy 0:fff4b9055396 205
sarahmarshy 0:fff4b9055396 206 return false;
sarahmarshy 0:fff4b9055396 207 }
sarahmarshy 0:fff4b9055396 208
sarahmarshy 2:12d08f0f20cf 209 bool DnsQuery::parseRR(char *resp, int& c, char* adr )
sarahmarshy 0:fff4b9055396 210 {
sarahmarshy 0:fff4b9055396 211 int n = 0;
sarahmarshy 0:fff4b9055396 212 while( (n=resp[c++]) != 0) {
sarahmarshy 0:fff4b9055396 213 if ((n & 0xc0) != 0) {
sarahmarshy 0:fff4b9055396 214 // This is a link
sarahmarshy 0:fff4b9055396 215 c++;
sarahmarshy 0:fff4b9055396 216 break;
sarahmarshy 0:fff4b9055396 217 } else {
sarahmarshy 0:fff4b9055396 218 c+= n; // skip this segment, not interested in string domain names
sarahmarshy 0:fff4b9055396 219 }
sarahmarshy 0:fff4b9055396 220 }
sarahmarshy 0:fff4b9055396 221
sarahmarshy 0:fff4b9055396 222 int TYPE = (((int)resp[c])<<8) + resp[c+1];
sarahmarshy 0:fff4b9055396 223 int CLASS = (((int)resp[c+2])<<8) + resp[c+3];
sarahmarshy 0:fff4b9055396 224 int RDLENGTH = (((int)resp[c+8])<<8) + resp[c+9];
sarahmarshy 0:fff4b9055396 225
sarahmarshy 0:fff4b9055396 226 INFO("Record of TYPE=%d and CLASS=%d detected !", TYPE, CLASS);
sarahmarshy 0:fff4b9055396 227 c+= 10;
sarahmarshy 0:fff4b9055396 228 if ((CLASS == 1) && (TYPE == 1)) {
sarahmarshy 2:12d08f0f20cf 229 sprintf(adr,"%d.%d.%d.%d", resp[c], resp[c+1], resp[c+2], resp[c+3]);
sarahmarshy 0:fff4b9055396 230 c+= RDLENGTH;
sarahmarshy 0:fff4b9055396 231 return true;
sarahmarshy 0:fff4b9055396 232 } else {
sarahmarshy 0:fff4b9055396 233 }
sarahmarshy 0:fff4b9055396 234 c+= RDLENGTH;
sarahmarshy 0:fff4b9055396 235
sarahmarshy 0:fff4b9055396 236 return false;
sarahmarshy 0:fff4b9055396 237 }