Takehisa Oneta / DnsQuery

modified by ohneta

Dependents:   HelloESP8266Interface_mine

Fork of DnsQuery by Sarah Marsh

DnsQuery.cpp@4:7e64d099f63e, 2015-11-10 (annotated)

Committer:
ohneta
Date:
Tue Nov 10 14:37:17 2015 +0000
Revision:
4:7e64d099f63e
Parent:
3:5705fdae6185
Child:
5:7555d509b568
added information of preferred DNS server.

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 4:7e64d099f63e 40 DnsQuery::DnsQuery(SocketInterface *sock, const char* hostname, char* ipaddress, const char *dnsIp)
sarahmarshy 0:fff4b9055396 41 {
sarahmarshy 1:5d978992a518 42 socket = sock;
ohneta 4:7e64d099f63e 43 this->setPreferredDNSServerIP(dnsIp);
sarahmarshy 3:5705fdae6185 44 this->getHostByName(hostname, ipaddress);
sarahmarshy 0:fff4b9055396 45 }
sarahmarshy 0:fff4b9055396 46
ohneta 4:7e64d099f63e 47 void DnsQuery::setPreferredDNSServerIP(const char *dnsIp)
ohneta 4:7e64d099f63e 48 {
ohneta 4:7e64d099f63e 49 _preferred_dnsip = dnsIp;
ohneta 4:7e64d099f63e 50 }
ohneta 4:7e64d099f63e 51
sarahmarshy 3:5705fdae6185 52 bool DnsQuery::getHostByName(const char* hostname, char* resolvedIp)
sarahmarshy 0:fff4b9055396 53 {
ohneta 4:7e64d099f63e 54 if (_preferred_dnsip != NULL) {
ohneta 4:7e64d099f63e 55 _dnsip = (char *)_preferred_dnsip;
ohneta 4:7e64d099f63e 56 if (this->getIP(hostname, resolvedIp)) {
ohneta 4:7e64d099f63e 57 return true;
ohneta 4:7e64d099f63e 58 }
ohneta 4:7e64d099f63e 59 }
ohneta 4:7e64d099f63e 60
sarahmarshy 2:12d08f0f20cf 61 char * dnsIPs[] = {
sarahmarshy 2:12d08f0f20cf 62 "8.8.8.8",
sarahmarshy 2:12d08f0f20cf 63 "209.244.0.3",
sarahmarshy 2:12d08f0f20cf 64 "84.200.69.80",
sarahmarshy 2:12d08f0f20cf 65 "8.26.56.26",
sarahmarshy 2:12d08f0f20cf 66 "208.67.222.222"
sarahmarshy 2:12d08f0f20cf 67 };
sarahmarshy 0:fff4b9055396 68 for(int i = 0; i<5; i++){
sarahmarshy 2:12d08f0f20cf 69 _dnsip = dnsIPs[i];
sarahmarshy 2:12d08f0f20cf 70 if(this->getIP(hostname, resolvedIp)){
sarahmarshy 0:fff4b9055396 71 return true;
sarahmarshy 0:fff4b9055396 72 }
sarahmarshy 0:fff4b9055396 73
sarahmarshy 0:fff4b9055396 74 }
sarahmarshy 0:fff4b9055396 75 return false;
sarahmarshy 0:fff4b9055396 76
sarahmarshy 0:fff4b9055396 77 }
sarahmarshy 0:fff4b9055396 78
sarahmarshy 2:12d08f0f20cf 79 bool DnsQuery::getIP(const char* hostname, char* ipaddress)
sarahmarshy 0:fff4b9055396 80 {
sarahmarshy 0:fff4b9055396 81 INFO("%s", hostname);
sarahmarshy 0:fff4b9055396 82 int len = 0;
sarahmarshy 0:fff4b9055396 83 if (hostname == NULL)
sarahmarshy 0:fff4b9055396 84 return false;
sarahmarshy 0:fff4b9055396 85 len = strlen(hostname);
sarahmarshy 0:fff4b9055396 86 if ((len >128) || (len == 0))
sarahmarshy 0:fff4b9055396 87 return false;
sarahmarshy 0:fff4b9055396 88
sarahmarshy 0:fff4b9055396 89 int packetlen = /* size of HEADER structure */ 12 + /* size of QUESTION Structure */5 + len + 1;
sarahmarshy 0:fff4b9055396 90 char *packet = new char[packetlen]; /* this is the UDP packet to send to the DNS */
sarahmarshy 0:fff4b9055396 91 if (packet == NULL)
sarahmarshy 0:fff4b9055396 92 return false;
sarahmarshy 0:fff4b9055396 93
sarahmarshy 0:fff4b9055396 94 // Fill the header
sarahmarshy 0:fff4b9055396 95 memset(packet, 0, packetlen);
sarahmarshy 0:fff4b9055396 96 packet[1] = 1; // ID = 1
sarahmarshy 0:fff4b9055396 97 packet[5] = 1; // QDCOUNT = 1 (contains one question)
sarahmarshy 0:fff4b9055396 98 packet[2] = 1; // recursion requested
sarahmarshy 0:fff4b9055396 99
sarahmarshy 0:fff4b9055396 100 int c = 13; // point to NAME element in question section or request
sarahmarshy 0:fff4b9055396 101 int cnt = 12; // points to the counter of
sarahmarshy 0:fff4b9055396 102 packet[cnt] = 0;
sarahmarshy 0:fff4b9055396 103 for (int i = 0 ; i < len ; i++) {
sarahmarshy 0:fff4b9055396 104 if (hostname[i] != '.') {
sarahmarshy 0:fff4b9055396 105 // Copy the character and increment the character counter
sarahmarshy 0:fff4b9055396 106 packet[cnt]++;
sarahmarshy 0:fff4b9055396 107 packet[c++] = hostname[i];
sarahmarshy 0:fff4b9055396 108 } else {
sarahmarshy 0:fff4b9055396 109 // Finished with this part, so go to the next
sarahmarshy 0:fff4b9055396 110 cnt = c++;
sarahmarshy 0:fff4b9055396 111 packet[cnt] = 0;
sarahmarshy 0:fff4b9055396 112 }
sarahmarshy 0:fff4b9055396 113 }
sarahmarshy 0:fff4b9055396 114
sarahmarshy 0:fff4b9055396 115 // Terminate this domain name with a zero entry
sarahmarshy 0:fff4b9055396 116 packet[c++] = 0;
sarahmarshy 0:fff4b9055396 117
sarahmarshy 0:fff4b9055396 118 // Set QTYPE
sarahmarshy 0:fff4b9055396 119 packet[c++] = 0;
sarahmarshy 0:fff4b9055396 120 packet[c++] = 1;
sarahmarshy 0:fff4b9055396 121 // Set QCLASS
sarahmarshy 0:fff4b9055396 122 packet[c++] = 0;
sarahmarshy 0:fff4b9055396 123 packet[c++] = 1;
sarahmarshy 0:fff4b9055396 124
sarahmarshy 0:fff4b9055396 125
sarahmarshy 0:fff4b9055396 126 // Ready to send to DNS
sarahmarshy 2:12d08f0f20cf 127 socket->setAddressPort(_dnsip, 53);
sarahmarshy 1:5d978992a518 128 socket->open();
sarahmarshy 0:fff4b9055396 129
sarahmarshy 1:5d978992a518 130 INFO("Sending packet of length %d",packetlen);
sarahmarshy 1:5d978992a518 131 /*
sarahmarshy 1:5d978992a518 132 for( int i = 0 ; i < c ; i++) {
sarahmarshy 1:5d978992a518 133 printf("%02x ", packet[i]);
sarahmarshy 1:5d978992a518 134 }
sarahmarshy 1:5d978992a518 135 */
sarahmarshy 1:5d978992a518 136 if (socket->send(packet, packetlen) < 0) {
sarahmarshy 0:fff4b9055396 137 delete packet;
sarahmarshy 0:fff4b9055396 138 return false;
sarahmarshy 0:fff4b9055396 139 }
sarahmarshy 0:fff4b9055396 140 delete packet;
sarahmarshy 0:fff4b9055396 141
sarahmarshy 0:fff4b9055396 142 packet = new char [1024];
sarahmarshy 0:fff4b9055396 143
sarahmarshy 0:fff4b9055396 144 // Receive the answer from DNS
sarahmarshy 0:fff4b9055396 145 int response_length = 0;
sarahmarshy 2:12d08f0f20cf 146 INFO("Recieving");
sarahmarshy 2:12d08f0f20cf 147 response_length = socket->recv(packet, 1024);
sarahmarshy 1:5d978992a518 148 /*
sarahmarshy 1:5d978992a518 149 for( int i = 0 ; i < 1024; i++) {
sarahmarshy 1:5d978992a518 150 printf("%02x ", packet[i]);
sarahmarshy 1:5d978992a518 151 }
sarahmarshy 1:5d978992a518 152 */
sarahmarshy 2:12d08f0f20cf 153 if (response_length > 0 ) {
sarahmarshy 2:12d08f0f20cf 154 if (!resolve(packet, ipaddress)) {
sarahmarshy 2:12d08f0f20cf 155 socket->close();
sarahmarshy 0:fff4b9055396 156 delete packet;
sarahmarshy 2:12d08f0f20cf 157 ERR("NO IP FOUND\n");
sarahmarshy 2:12d08f0f20cf 158 return false;
sarahmarshy 0:fff4b9055396 159 }
sarahmarshy 2:12d08f0f20cf 160
sarahmarshy 2:12d08f0f20cf 161 // cleanup and return
sarahmarshy 2:12d08f0f20cf 162 delete packet;
sarahmarshy 2:12d08f0f20cf 163 socket->close();
sarahmarshy 2:12d08f0f20cf 164 return true;
sarahmarshy 2:12d08f0f20cf 165 } else {
sarahmarshy 2:12d08f0f20cf 166 ERR("SocketRecvFrom returned %d !", response_length);
sarahmarshy 2:12d08f0f20cf 167 }
sarahmarshy 1:5d978992a518 168 socket->close();
sarahmarshy 0:fff4b9055396 169 delete packet;
sarahmarshy 0:fff4b9055396 170 ERR("NO IP FOUND\n");
sarahmarshy 0:fff4b9055396 171 return false;
sarahmarshy 0:fff4b9055396 172 }
sarahmarshy 0:fff4b9055396 173
sarahmarshy 0:fff4b9055396 174
sarahmarshy 2:12d08f0f20cf 175 bool DnsQuery::resolve(char* resp, char* ipaddress)
sarahmarshy 0:fff4b9055396 176 {
sarahmarshy 0:fff4b9055396 177
sarahmarshy 0:fff4b9055396 178 int ID = (((int)resp[0]) <<8) + resp[1];
sarahmarshy 0:fff4b9055396 179 int QR = resp[2] >>7;
sarahmarshy 0:fff4b9055396 180 int Opcode = (resp[2]>>3) & 0x0F;
sarahmarshy 0:fff4b9055396 181 int RCODE = (resp[3] & 0x0F);
sarahmarshy 0:fff4b9055396 182 int ANCOUNT = (((int)resp[6])<<8)+ resp[7];
sarahmarshy 0:fff4b9055396 183
sarahmarshy 0:fff4b9055396 184 INFO("Resolving response : ID = %d, QR = %d, Opcode = %d, RCODE = %d", ID, QR, Opcode, RCODE);
sarahmarshy 0:fff4b9055396 185 if ((ID != 1) || (QR != 1) || (Opcode != 0) || (RCODE != 0)) {
sarahmarshy 0:fff4b9055396 186 ERR("Received non matching response from DNS !");
sarahmarshy 0:fff4b9055396 187 return false;
sarahmarshy 0:fff4b9055396 188 }
sarahmarshy 0:fff4b9055396 189
sarahmarshy 0:fff4b9055396 190 int c = 12;
sarahmarshy 0:fff4b9055396 191 int d;
sarahmarshy 0:fff4b9055396 192 // Skip domain question
sarahmarshy 0:fff4b9055396 193 while( (d=resp[c++]) != 0) {
sarahmarshy 0:fff4b9055396 194 c+=d;
sarahmarshy 0:fff4b9055396 195 }
sarahmarshy 0:fff4b9055396 196 c+= 4; // skip QTYPE and QCLASS
sarahmarshy 0:fff4b9055396 197
sarahmarshy 0:fff4b9055396 198 // Here comes the resource record
sarahmarshy 0:fff4b9055396 199 for (int ans = 0 ; ans < ANCOUNT; ans++) {
sarahmarshy 0:fff4b9055396 200 if (parseRR(resp, c, ipaddress)) {
sarahmarshy 0:fff4b9055396 201 return true;
sarahmarshy 0:fff4b9055396 202 }
sarahmarshy 0:fff4b9055396 203 }
sarahmarshy 0:fff4b9055396 204
sarahmarshy 0:fff4b9055396 205 return false;
sarahmarshy 0:fff4b9055396 206 }
sarahmarshy 0:fff4b9055396 207
sarahmarshy 2:12d08f0f20cf 208 bool DnsQuery::parseRR(char *resp, int& c, char* adr )
sarahmarshy 0:fff4b9055396 209 {
sarahmarshy 0:fff4b9055396 210 int n = 0;
sarahmarshy 0:fff4b9055396 211 while( (n=resp[c++]) != 0) {
sarahmarshy 0:fff4b9055396 212 if ((n & 0xc0) != 0) {
sarahmarshy 0:fff4b9055396 213 // This is a link
sarahmarshy 0:fff4b9055396 214 c++;
sarahmarshy 0:fff4b9055396 215 break;
sarahmarshy 0:fff4b9055396 216 } else {
sarahmarshy 0:fff4b9055396 217 c+= n; // skip this segment, not interested in string domain names
sarahmarshy 0:fff4b9055396 218 }
sarahmarshy 0:fff4b9055396 219 }
sarahmarshy 0:fff4b9055396 220
sarahmarshy 0:fff4b9055396 221 int TYPE = (((int)resp[c])<<8) + resp[c+1];
sarahmarshy 0:fff4b9055396 222 int CLASS = (((int)resp[c+2])<<8) + resp[c+3];
sarahmarshy 0:fff4b9055396 223 int RDLENGTH = (((int)resp[c+8])<<8) + resp[c+9];
sarahmarshy 0:fff4b9055396 224
sarahmarshy 0:fff4b9055396 225 INFO("Record of TYPE=%d and CLASS=%d detected !", TYPE, CLASS);
sarahmarshy 0:fff4b9055396 226 c+= 10;
sarahmarshy 0:fff4b9055396 227 if ((CLASS == 1) && (TYPE == 1)) {
sarahmarshy 2:12d08f0f20cf 228 sprintf(adr,"%d.%d.%d.%d", resp[c], resp[c+1], resp[c+2], resp[c+3]);
sarahmarshy 0:fff4b9055396 229 c+= RDLENGTH;
sarahmarshy 0:fff4b9055396 230 return true;
sarahmarshy 0:fff4b9055396 231 } else {
sarahmarshy 0:fff4b9055396 232 }
sarahmarshy 0:fff4b9055396 233 c+= RDLENGTH;
sarahmarshy 0:fff4b9055396 234
sarahmarshy 0:fff4b9055396 235 return false;
sarahmarshy 0:fff4b9055396 236 }