DongEun Koak / DnsQuery

DnsQuery for NetworkSocketAPI

Fork of DnsQuery by NetworkSocketAPI

DnsQuery.cpp@4:3749346dcd59, 2016-02-22 (annotated)

Committer:
Christopher Haster
Date:
Mon Feb 22 19:31:19 2016 -0600
Revision:
4:3749346dcd59
Parent:
3:5705fdae6185
Child:
5:d85c1a7e0e9f
Removed dependency on mbed

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 "DnsQuery.h"
Christopher Haster 4:3749346dcd59 19 #include <stdio.h>
Christopher Haster 4:3749346dcd59 20 #include <string.h>
sarahmarshy 0:fff4b9055396 21
sarahmarshy 0:fff4b9055396 22 //Debug is disabled by default
sarahmarshy 0:fff4b9055396 23 #if 0
sarahmarshy 0:fff4b9055396 24 #define DBG(x, ...) printf("[DNS : DBG]"x" \t[%s,%d]\r\n", ##__VA_ARGS__,__FILE__,__LINE__);
sarahmarshy 0:fff4b9055396 25 #define WARN(x, ...) printf("[DNS : WARN]"x" \t[%s,%d]\r\n", ##__VA_ARGS__,__FILE__,__LINE__);
sarahmarshy 0:fff4b9055396 26 #define ERR(x, ...) printf("[DNS : ERR]"x" \t[%s,%d]\r\n", ##__VA_ARGS__,__FILE__,__LINE__);
sarahmarshy 0:fff4b9055396 27 #else
sarahmarshy 0:fff4b9055396 28 #define DBG(x, ...) //wait_us(10);
sarahmarshy 0:fff4b9055396 29 #define WARN(x, ...) //wait_us(10);
sarahmarshy 0:fff4b9055396 30 #define ERR(x, ...)
sarahmarshy 0:fff4b9055396 31 #endif
sarahmarshy 0:fff4b9055396 32
sarahmarshy 0:fff4b9055396 33 #if 0
sarahmarshy 0:fff4b9055396 34 #define INFO(x, ...) printf("[DNS : INFO]"x" \t[%s,%d]\r\n", ##__VA_ARGS__,__FILE__,__LINE__);
sarahmarshy 0:fff4b9055396 35 #else
sarahmarshy 0:fff4b9055396 36 #define INFO(x, ...)
sarahmarshy 0:fff4b9055396 37 #endif
sarahmarshy 0:fff4b9055396 38
sarahmarshy 0:fff4b9055396 39
sarahmarshy 0:fff4b9055396 40
sarahmarshy 3:5705fdae6185 41 DnsQuery::DnsQuery(SocketInterface *sock,const char* hostname, char* ipaddress)
sarahmarshy 0:fff4b9055396 42 {
sarahmarshy 1:5d978992a518 43 socket = sock;
sarahmarshy 3:5705fdae6185 44 this->getHostByName(hostname, ipaddress);
sarahmarshy 0:fff4b9055396 45 }
sarahmarshy 0:fff4b9055396 46
sarahmarshy 3:5705fdae6185 47 bool DnsQuery::getHostByName(const char* hostname, char* resolvedIp)
sarahmarshy 0:fff4b9055396 48 {
Christopher Haster 4:3749346dcd59 49 const char * dnsIPs[] = {
sarahmarshy 2:12d08f0f20cf 50 "8.8.8.8",
sarahmarshy 2:12d08f0f20cf 51 "209.244.0.3",
sarahmarshy 2:12d08f0f20cf 52 "84.200.69.80",
sarahmarshy 2:12d08f0f20cf 53 "8.26.56.26",
sarahmarshy 2:12d08f0f20cf 54 "208.67.222.222"
sarahmarshy 2:12d08f0f20cf 55 };
sarahmarshy 0:fff4b9055396 56 for(int i = 0; i<5; i++){
sarahmarshy 2:12d08f0f20cf 57 _dnsip = dnsIPs[i];
sarahmarshy 2:12d08f0f20cf 58 if(this->getIP(hostname, resolvedIp)){
sarahmarshy 0:fff4b9055396 59 return true;
sarahmarshy 0:fff4b9055396 60 }
sarahmarshy 0:fff4b9055396 61
sarahmarshy 0:fff4b9055396 62 }
sarahmarshy 0:fff4b9055396 63 return false;
sarahmarshy 0:fff4b9055396 64
sarahmarshy 0:fff4b9055396 65 }
sarahmarshy 0:fff4b9055396 66
sarahmarshy 2:12d08f0f20cf 67 bool DnsQuery::getIP(const char* hostname, char* ipaddress)
sarahmarshy 0:fff4b9055396 68 {
sarahmarshy 0:fff4b9055396 69 INFO("%s", hostname);
sarahmarshy 0:fff4b9055396 70 int len = 0;
sarahmarshy 0:fff4b9055396 71 if (hostname == NULL)
sarahmarshy 0:fff4b9055396 72 return false;
sarahmarshy 0:fff4b9055396 73 len = strlen(hostname);
sarahmarshy 0:fff4b9055396 74 if ((len >128) || (len == 0))
sarahmarshy 0:fff4b9055396 75 return false;
sarahmarshy 0:fff4b9055396 76
sarahmarshy 0:fff4b9055396 77 int packetlen = /* size of HEADER structure */ 12 + /* size of QUESTION Structure */5 + len + 1;
sarahmarshy 0:fff4b9055396 78 char *packet = new char[packetlen]; /* this is the UDP packet to send to the DNS */
sarahmarshy 0:fff4b9055396 79 if (packet == NULL)
sarahmarshy 0:fff4b9055396 80 return false;
sarahmarshy 0:fff4b9055396 81
sarahmarshy 0:fff4b9055396 82 // Fill the header
sarahmarshy 0:fff4b9055396 83 memset(packet, 0, packetlen);
sarahmarshy 0:fff4b9055396 84 packet[1] = 1; // ID = 1
sarahmarshy 0:fff4b9055396 85 packet[5] = 1; // QDCOUNT = 1 (contains one question)
sarahmarshy 0:fff4b9055396 86 packet[2] = 1; // recursion requested
sarahmarshy 0:fff4b9055396 87
sarahmarshy 0:fff4b9055396 88 int c = 13; // point to NAME element in question section or request
sarahmarshy 0:fff4b9055396 89 int cnt = 12; // points to the counter of
sarahmarshy 0:fff4b9055396 90 packet[cnt] = 0;
sarahmarshy 0:fff4b9055396 91 for (int i = 0 ; i < len ; i++) {
sarahmarshy 0:fff4b9055396 92 if (hostname[i] != '.') {
sarahmarshy 0:fff4b9055396 93 // Copy the character and increment the character counter
sarahmarshy 0:fff4b9055396 94 packet[cnt]++;
sarahmarshy 0:fff4b9055396 95 packet[c++] = hostname[i];
sarahmarshy 0:fff4b9055396 96 } else {
sarahmarshy 0:fff4b9055396 97 // Finished with this part, so go to the next
sarahmarshy 0:fff4b9055396 98 cnt = c++;
sarahmarshy 0:fff4b9055396 99 packet[cnt] = 0;
sarahmarshy 0:fff4b9055396 100 }
sarahmarshy 0:fff4b9055396 101 }
sarahmarshy 0:fff4b9055396 102
sarahmarshy 0:fff4b9055396 103 // Terminate this domain name with a zero entry
sarahmarshy 0:fff4b9055396 104 packet[c++] = 0;
sarahmarshy 0:fff4b9055396 105
sarahmarshy 0:fff4b9055396 106 // Set QTYPE
sarahmarshy 0:fff4b9055396 107 packet[c++] = 0;
sarahmarshy 0:fff4b9055396 108 packet[c++] = 1;
sarahmarshy 0:fff4b9055396 109 // Set QCLASS
sarahmarshy 0:fff4b9055396 110 packet[c++] = 0;
sarahmarshy 0:fff4b9055396 111 packet[c++] = 1;
sarahmarshy 0:fff4b9055396 112
sarahmarshy 0:fff4b9055396 113
sarahmarshy 0:fff4b9055396 114 // Ready to send to DNS
sarahmarshy 2:12d08f0f20cf 115 socket->setAddressPort(_dnsip, 53);
sarahmarshy 1:5d978992a518 116 socket->open();
sarahmarshy 0:fff4b9055396 117
sarahmarshy 1:5d978992a518 118 INFO("Sending packet of length %d",packetlen);
sarahmarshy 1:5d978992a518 119 /*
sarahmarshy 1:5d978992a518 120 for( int i = 0 ; i < c ; i++) {
sarahmarshy 1:5d978992a518 121 printf("%02x ", packet[i]);
sarahmarshy 1:5d978992a518 122 }
sarahmarshy 1:5d978992a518 123 */
sarahmarshy 1:5d978992a518 124 if (socket->send(packet, packetlen) < 0) {
sarahmarshy 0:fff4b9055396 125 delete packet;
sarahmarshy 0:fff4b9055396 126 return false;
sarahmarshy 0:fff4b9055396 127 }
sarahmarshy 0:fff4b9055396 128 delete packet;
sarahmarshy 0:fff4b9055396 129
sarahmarshy 0:fff4b9055396 130 packet = new char [1024];
sarahmarshy 0:fff4b9055396 131
sarahmarshy 0:fff4b9055396 132 // Receive the answer from DNS
sarahmarshy 0:fff4b9055396 133 int response_length = 0;
sarahmarshy 2:12d08f0f20cf 134 INFO("Recieving");
sarahmarshy 2:12d08f0f20cf 135 response_length = socket->recv(packet, 1024);
sarahmarshy 1:5d978992a518 136 /*
sarahmarshy 1:5d978992a518 137 for( int i = 0 ; i < 1024; i++) {
sarahmarshy 1:5d978992a518 138 printf("%02x ", packet[i]);
sarahmarshy 1:5d978992a518 139 }
sarahmarshy 1:5d978992a518 140 */
sarahmarshy 2:12d08f0f20cf 141 if (response_length > 0 ) {
sarahmarshy 2:12d08f0f20cf 142 if (!resolve(packet, ipaddress)) {
sarahmarshy 2:12d08f0f20cf 143 socket->close();
sarahmarshy 0:fff4b9055396 144 delete packet;
sarahmarshy 2:12d08f0f20cf 145 ERR("NO IP FOUND\n");
sarahmarshy 2:12d08f0f20cf 146 return false;
sarahmarshy 0:fff4b9055396 147 }
sarahmarshy 2:12d08f0f20cf 148
sarahmarshy 2:12d08f0f20cf 149 // cleanup and return
sarahmarshy 2:12d08f0f20cf 150 delete packet;
sarahmarshy 2:12d08f0f20cf 151 socket->close();
sarahmarshy 2:12d08f0f20cf 152 return true;
sarahmarshy 2:12d08f0f20cf 153 } else {
sarahmarshy 2:12d08f0f20cf 154 ERR("SocketRecvFrom returned %d !", response_length);
sarahmarshy 2:12d08f0f20cf 155 }
sarahmarshy 1:5d978992a518 156 socket->close();
sarahmarshy 0:fff4b9055396 157 delete packet;
sarahmarshy 0:fff4b9055396 158 ERR("NO IP FOUND\n");
sarahmarshy 0:fff4b9055396 159 return false;
sarahmarshy 0:fff4b9055396 160 }
sarahmarshy 0:fff4b9055396 161
sarahmarshy 0:fff4b9055396 162
sarahmarshy 2:12d08f0f20cf 163 bool DnsQuery::resolve(char* resp, char* ipaddress)
sarahmarshy 0:fff4b9055396 164 {
sarahmarshy 0:fff4b9055396 165
sarahmarshy 0:fff4b9055396 166 int ID = (((int)resp[0]) <<8) + resp[1];
sarahmarshy 0:fff4b9055396 167 int QR = resp[2] >>7;
sarahmarshy 0:fff4b9055396 168 int Opcode = (resp[2]>>3) & 0x0F;
sarahmarshy 0:fff4b9055396 169 int RCODE = (resp[3] & 0x0F);
sarahmarshy 0:fff4b9055396 170 int ANCOUNT = (((int)resp[6])<<8)+ resp[7];
sarahmarshy 0:fff4b9055396 171
sarahmarshy 0:fff4b9055396 172 INFO("Resolving response : ID = %d, QR = %d, Opcode = %d, RCODE = %d", ID, QR, Opcode, RCODE);
sarahmarshy 0:fff4b9055396 173 if ((ID != 1) || (QR != 1) || (Opcode != 0) || (RCODE != 0)) {
sarahmarshy 0:fff4b9055396 174 ERR("Received non matching response from DNS !");
sarahmarshy 0:fff4b9055396 175 return false;
sarahmarshy 0:fff4b9055396 176 }
sarahmarshy 0:fff4b9055396 177
sarahmarshy 0:fff4b9055396 178 int c = 12;
sarahmarshy 0:fff4b9055396 179 int d;
sarahmarshy 0:fff4b9055396 180 // Skip domain question
sarahmarshy 0:fff4b9055396 181 while( (d=resp[c++]) != 0) {
sarahmarshy 0:fff4b9055396 182 c+=d;
sarahmarshy 0:fff4b9055396 183 }
sarahmarshy 0:fff4b9055396 184 c+= 4; // skip QTYPE and QCLASS
sarahmarshy 0:fff4b9055396 185
sarahmarshy 0:fff4b9055396 186 // Here comes the resource record
sarahmarshy 0:fff4b9055396 187 for (int ans = 0 ; ans < ANCOUNT; ans++) {
sarahmarshy 0:fff4b9055396 188 if (parseRR(resp, c, ipaddress)) {
sarahmarshy 0:fff4b9055396 189 return true;
sarahmarshy 0:fff4b9055396 190 }
sarahmarshy 0:fff4b9055396 191 }
sarahmarshy 0:fff4b9055396 192
sarahmarshy 0:fff4b9055396 193 return false;
sarahmarshy 0:fff4b9055396 194 }
sarahmarshy 0:fff4b9055396 195
sarahmarshy 2:12d08f0f20cf 196 bool DnsQuery::parseRR(char *resp, int& c, char* adr )
sarahmarshy 0:fff4b9055396 197 {
sarahmarshy 0:fff4b9055396 198 int n = 0;
sarahmarshy 0:fff4b9055396 199 while( (n=resp[c++]) != 0) {
sarahmarshy 0:fff4b9055396 200 if ((n & 0xc0) != 0) {
sarahmarshy 0:fff4b9055396 201 // This is a link
sarahmarshy 0:fff4b9055396 202 c++;
sarahmarshy 0:fff4b9055396 203 break;
sarahmarshy 0:fff4b9055396 204 } else {
sarahmarshy 0:fff4b9055396 205 c+= n; // skip this segment, not interested in string domain names
sarahmarshy 0:fff4b9055396 206 }
sarahmarshy 0:fff4b9055396 207 }
sarahmarshy 0:fff4b9055396 208
sarahmarshy 0:fff4b9055396 209 int TYPE = (((int)resp[c])<<8) + resp[c+1];
sarahmarshy 0:fff4b9055396 210 int CLASS = (((int)resp[c+2])<<8) + resp[c+3];
sarahmarshy 0:fff4b9055396 211 int RDLENGTH = (((int)resp[c+8])<<8) + resp[c+9];
sarahmarshy 0:fff4b9055396 212
sarahmarshy 0:fff4b9055396 213 INFO("Record of TYPE=%d and CLASS=%d detected !", TYPE, CLASS);
sarahmarshy 0:fff4b9055396 214 c+= 10;
sarahmarshy 0:fff4b9055396 215 if ((CLASS == 1) && (TYPE == 1)) {
sarahmarshy 2:12d08f0f20cf 216 sprintf(adr,"%d.%d.%d.%d", resp[c], resp[c+1], resp[c+2], resp[c+3]);
sarahmarshy 0:fff4b9055396 217 c+= RDLENGTH;
sarahmarshy 0:fff4b9055396 218 return true;
sarahmarshy 0:fff4b9055396 219 } else {
sarahmarshy 0:fff4b9055396 220 }
sarahmarshy 0:fff4b9055396 221 c+= RDLENGTH;
sarahmarshy 0:fff4b9055396 222
sarahmarshy 0:fff4b9055396 223 return false;
Christopher Haster 4:3749346dcd59 224 }