NetworkSocketAPI / DnsQuery

Library to resolve text URLs to IP addresses (IPv4)

Dependents:   NetworkSocketAPI NetworkSocketAPI Nucleo-AWS-IoT-mbed

DnsQuery.cpp@1:5d978992a518, 2015-07-24 (annotated)

Committer:
sarahmarshy
Date:
Fri Jul 24 22:43:25 2015 +0000
Revision:
1:5d978992a518
Parent:
0:fff4b9055396
Child:
2:12d08f0f20cf
Compatibility with new SocketInterface

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
sarahmarshy 1:5d978992a518 40 DnsQuery::DnsQuery(SocketInterface *sock)
sarahmarshy 0:fff4b9055396 41 {
sarahmarshy 1:5d978992a518 42 socket = sock;
sarahmarshy 0:fff4b9055396 43 }
sarahmarshy 0:fff4b9055396 44
sarahmarshy 1:5d978992a518 45 bool DnsQuery::gethostbyname(const char* hostname, IPADDRESS_t &ipaddress)
sarahmarshy 0:fff4b9055396 46 {
sarahmarshy 0:fff4b9055396 47 IPADDRESS_t dnsIp_1 = {209,244,0,3};
sarahmarshy 0:fff4b9055396 48 IPADDRESS_t dnsIp_2 = {8,8,8,8};
sarahmarshy 0:fff4b9055396 49 IPADDRESS_t dnsIp_3 = {84,200,69,80};
sarahmarshy 0:fff4b9055396 50 IPADDRESS_t dnsIp_4 = {8,26,56,26};
sarahmarshy 0:fff4b9055396 51 IPADDRESS_t dnsIp_5 = {208,67,222,222};
sarahmarshy 0:fff4b9055396 52 for(int i = 0; i<5; i++){
sarahmarshy 0:fff4b9055396 53 switch(i) {
sarahmarshy 1:5d978992a518 54 case 0 : _dnsip= dnsIp_1; break ;
sarahmarshy 1:5d978992a518 55 case 1 : _dnsip= dnsIp_2; break ;
sarahmarshy 1:5d978992a518 56 case 2 : _dnsip= dnsIp_3; break ;
sarahmarshy 1:5d978992a518 57 case 3 : _dnsip= dnsIp_4; break ;
sarahmarshy 1:5d978992a518 58 case 4 : _dnsip= dnsIp_5; break ;
sarahmarshy 0:fff4b9055396 59 }
sarahmarshy 1:5d978992a518 60 if(this->getIP(hostname, ipaddress)){
sarahmarshy 0:fff4b9055396 61 return true;
sarahmarshy 0:fff4b9055396 62 }
sarahmarshy 0:fff4b9055396 63
sarahmarshy 0:fff4b9055396 64 }
sarahmarshy 0:fff4b9055396 65 return false;
sarahmarshy 0:fff4b9055396 66
sarahmarshy 0:fff4b9055396 67 }
sarahmarshy 0:fff4b9055396 68
sarahmarshy 1:5d978992a518 69 bool DnsQuery::getIP(const char* hostname, IPADDRESS_t &ipaddress)
sarahmarshy 0:fff4b9055396 70 {
sarahmarshy 0:fff4b9055396 71 INFO("%s", hostname);
sarahmarshy 0:fff4b9055396 72 int len = 0;
sarahmarshy 0:fff4b9055396 73 if (hostname == NULL)
sarahmarshy 0:fff4b9055396 74 return false;
sarahmarshy 0:fff4b9055396 75 len = strlen(hostname);
sarahmarshy 0:fff4b9055396 76 if ((len >128) || (len == 0))
sarahmarshy 0:fff4b9055396 77 return false;
sarahmarshy 0:fff4b9055396 78 memset (&ipaddress, 0, sizeof(ipaddress));
sarahmarshy 0:fff4b9055396 79
sarahmarshy 0:fff4b9055396 80 int packetlen = /* size of HEADER structure */ 12 + /* size of QUESTION Structure */5 + len + 1;
sarahmarshy 0:fff4b9055396 81 char *packet = new char[packetlen]; /* this is the UDP packet to send to the DNS */
sarahmarshy 0:fff4b9055396 82 if (packet == NULL)
sarahmarshy 0:fff4b9055396 83 return false;
sarahmarshy 0:fff4b9055396 84
sarahmarshy 0:fff4b9055396 85 // Fill the header
sarahmarshy 0:fff4b9055396 86 memset(packet, 0, packetlen);
sarahmarshy 0:fff4b9055396 87 packet[1] = 1; // ID = 1
sarahmarshy 0:fff4b9055396 88 packet[5] = 1; // QDCOUNT = 1 (contains one question)
sarahmarshy 0:fff4b9055396 89 packet[2] = 1; // recursion requested
sarahmarshy 0:fff4b9055396 90
sarahmarshy 0:fff4b9055396 91 int c = 13; // point to NAME element in question section or request
sarahmarshy 0:fff4b9055396 92 int cnt = 12; // points to the counter of
sarahmarshy 0:fff4b9055396 93 packet[cnt] = 0;
sarahmarshy 0:fff4b9055396 94 for (int i = 0 ; i < len ; i++) {
sarahmarshy 0:fff4b9055396 95 if (hostname[i] != '.') {
sarahmarshy 0:fff4b9055396 96 // Copy the character and increment the character counter
sarahmarshy 0:fff4b9055396 97 packet[cnt]++;
sarahmarshy 0:fff4b9055396 98 packet[c++] = hostname[i];
sarahmarshy 0:fff4b9055396 99 } else {
sarahmarshy 0:fff4b9055396 100 // Finished with this part, so go to the next
sarahmarshy 0:fff4b9055396 101 cnt = c++;
sarahmarshy 0:fff4b9055396 102 packet[cnt] = 0;
sarahmarshy 0:fff4b9055396 103 }
sarahmarshy 0:fff4b9055396 104 }
sarahmarshy 0:fff4b9055396 105
sarahmarshy 0:fff4b9055396 106 // Terminate this domain name with a zero entry
sarahmarshy 0:fff4b9055396 107 packet[c++] = 0;
sarahmarshy 0:fff4b9055396 108
sarahmarshy 0:fff4b9055396 109 // Set QTYPE
sarahmarshy 0:fff4b9055396 110 packet[c++] = 0;
sarahmarshy 0:fff4b9055396 111 packet[c++] = 1;
sarahmarshy 0:fff4b9055396 112 // Set QCLASS
sarahmarshy 0:fff4b9055396 113 packet[c++] = 0;
sarahmarshy 0:fff4b9055396 114 packet[c++] = 1;
sarahmarshy 0:fff4b9055396 115
sarahmarshy 0:fff4b9055396 116
sarahmarshy 0:fff4b9055396 117 // Ready to send to DNS
sarahmarshy 1:5d978992a518 118 socket->setAddressPort(_dnsip.string_format(), 53);
sarahmarshy 1:5d978992a518 119 socket->open();
sarahmarshy 0:fff4b9055396 120
sarahmarshy 1:5d978992a518 121 INFO("Sending packet of length %d",packetlen);
sarahmarshy 1:5d978992a518 122 /*
sarahmarshy 1:5d978992a518 123 for( int i = 0 ; i < c ; i++) {
sarahmarshy 1:5d978992a518 124 printf("%02x ", packet[i]);
sarahmarshy 1:5d978992a518 125 }
sarahmarshy 1:5d978992a518 126 */
sarahmarshy 1:5d978992a518 127 if (socket->send(packet, packetlen) < 0) {
sarahmarshy 0:fff4b9055396 128 delete packet;
sarahmarshy 0:fff4b9055396 129 return false;
sarahmarshy 0:fff4b9055396 130 }
sarahmarshy 0:fff4b9055396 131
sarahmarshy 0:fff4b9055396 132 delete packet;
sarahmarshy 0:fff4b9055396 133
sarahmarshy 0:fff4b9055396 134 packet = new char [1024];
sarahmarshy 0:fff4b9055396 135 if (packet == NULL) {
sarahmarshy 0:fff4b9055396 136 return false;
sarahmarshy 0:fff4b9055396 137 }
sarahmarshy 0:fff4b9055396 138
sarahmarshy 0:fff4b9055396 139 // Receive the answer from DNS
sarahmarshy 0:fff4b9055396 140 Timer t;
sarahmarshy 0:fff4b9055396 141 t.start();
sarahmarshy 0:fff4b9055396 142 int response_length = 0;
sarahmarshy 0:fff4b9055396 143 while (t.read_ms() < 10000) {
sarahmarshy 0:fff4b9055396 144 INFO("Recieving");
sarahmarshy 1:5d978992a518 145 response_length = socket->recv(packet, 1024);
sarahmarshy 1:5d978992a518 146 /*
sarahmarshy 1:5d978992a518 147 for( int i = 0 ; i < 1024; i++) {
sarahmarshy 1:5d978992a518 148 printf("%02x ", packet[i]);
sarahmarshy 1:5d978992a518 149 }
sarahmarshy 1:5d978992a518 150 */
sarahmarshy 0:fff4b9055396 151 if (response_length > 0 ) {
sarahmarshy 1:5d978992a518 152 if (!resolve(packet, ipaddress)) {
sarahmarshy 0:fff4b9055396 153 break;
sarahmarshy 0:fff4b9055396 154 }
sarahmarshy 0:fff4b9055396 155
sarahmarshy 0:fff4b9055396 156 // cleanup and return
sarahmarshy 0:fff4b9055396 157 delete packet;
sarahmarshy 1:5d978992a518 158 socket->close();
sarahmarshy 0:fff4b9055396 159 //INFO("Found this IP:%s",ipaddress.string_format());
sarahmarshy 0:fff4b9055396 160 return true;
sarahmarshy 0:fff4b9055396 161 } else {
sarahmarshy 0:fff4b9055396 162 ERR("SocketRecvFrom returned %d !", response_length);
sarahmarshy 0:fff4b9055396 163 }
sarahmarshy 0:fff4b9055396 164 }
sarahmarshy 1:5d978992a518 165 socket->close();
sarahmarshy 0:fff4b9055396 166 delete packet;
sarahmarshy 0:fff4b9055396 167 ERR("NO IP FOUND\n");
sarahmarshy 0:fff4b9055396 168 return false;
sarahmarshy 0:fff4b9055396 169 }
sarahmarshy 0:fff4b9055396 170
sarahmarshy 0:fff4b9055396 171
sarahmarshy 0:fff4b9055396 172 bool DnsQuery::resolve(char* resp, IPADDRESS_t &ipaddress)
sarahmarshy 0:fff4b9055396 173 {
sarahmarshy 0:fff4b9055396 174
sarahmarshy 0:fff4b9055396 175 int ID = (((int)resp[0]) <<8) + resp[1];
sarahmarshy 0:fff4b9055396 176 int QR = resp[2] >>7;
sarahmarshy 0:fff4b9055396 177 int Opcode = (resp[2]>>3) & 0x0F;
sarahmarshy 0:fff4b9055396 178 int RCODE = (resp[3] & 0x0F);
sarahmarshy 0:fff4b9055396 179 int ANCOUNT = (((int)resp[6])<<8)+ resp[7];
sarahmarshy 0:fff4b9055396 180
sarahmarshy 0:fff4b9055396 181 INFO("Resolving response : ID = %d, QR = %d, Opcode = %d, RCODE = %d", ID, QR, Opcode, RCODE);
sarahmarshy 0:fff4b9055396 182 if ((ID != 1) || (QR != 1) || (Opcode != 0) || (RCODE != 0)) {
sarahmarshy 0:fff4b9055396 183 ERR("Received non matching response from DNS !");
sarahmarshy 0:fff4b9055396 184 return false;
sarahmarshy 0:fff4b9055396 185 }
sarahmarshy 0:fff4b9055396 186
sarahmarshy 0:fff4b9055396 187 int c = 12;
sarahmarshy 0:fff4b9055396 188 int d;
sarahmarshy 0:fff4b9055396 189 // Skip domain question
sarahmarshy 0:fff4b9055396 190 while( (d=resp[c++]) != 0) {
sarahmarshy 0:fff4b9055396 191 c+=d;
sarahmarshy 0:fff4b9055396 192 }
sarahmarshy 0:fff4b9055396 193 c+= 4; // skip QTYPE and QCLASS
sarahmarshy 0:fff4b9055396 194
sarahmarshy 0:fff4b9055396 195 // Here comes the resource record
sarahmarshy 0:fff4b9055396 196 for (int ans = 0 ; ans < ANCOUNT; ans++) {
sarahmarshy 0:fff4b9055396 197 if (parseRR(resp, c, ipaddress)) {
sarahmarshy 0:fff4b9055396 198 return true;
sarahmarshy 0:fff4b9055396 199 }
sarahmarshy 0:fff4b9055396 200 }
sarahmarshy 0:fff4b9055396 201
sarahmarshy 0:fff4b9055396 202 return false;
sarahmarshy 0:fff4b9055396 203 }
sarahmarshy 0:fff4b9055396 204
sarahmarshy 0:fff4b9055396 205 bool DnsQuery::parseRR(char *resp, int& c, IPADDRESS_t& adr )
sarahmarshy 0:fff4b9055396 206 {
sarahmarshy 0:fff4b9055396 207 int n = 0;
sarahmarshy 0:fff4b9055396 208
sarahmarshy 0:fff4b9055396 209 while( (n=resp[c++]) != 0) {
sarahmarshy 0:fff4b9055396 210 if ((n & 0xc0) != 0) {
sarahmarshy 0:fff4b9055396 211 // This is a link
sarahmarshy 0:fff4b9055396 212 c++;
sarahmarshy 0:fff4b9055396 213 break;
sarahmarshy 0:fff4b9055396 214 } else {
sarahmarshy 0:fff4b9055396 215 c+= n; // skip this segment, not interested in string domain names
sarahmarshy 0:fff4b9055396 216 }
sarahmarshy 0:fff4b9055396 217 }
sarahmarshy 0:fff4b9055396 218
sarahmarshy 0:fff4b9055396 219 int TYPE = (((int)resp[c])<<8) + resp[c+1];
sarahmarshy 0:fff4b9055396 220 int CLASS = (((int)resp[c+2])<<8) + resp[c+3];
sarahmarshy 0:fff4b9055396 221 int RDLENGTH = (((int)resp[c+8])<<8) + resp[c+9];
sarahmarshy 0:fff4b9055396 222
sarahmarshy 0:fff4b9055396 223 INFO("Record of TYPE=%d and CLASS=%d detected !", TYPE, CLASS);
sarahmarshy 0:fff4b9055396 224 c+= 10;
sarahmarshy 0:fff4b9055396 225 if ((CLASS == 1) && (TYPE == 1)) {
sarahmarshy 0:fff4b9055396 226 adr.sin_addr.o1 = resp[c];
sarahmarshy 0:fff4b9055396 227 adr.sin_addr.o2 = resp[c+1];
sarahmarshy 0:fff4b9055396 228 adr.sin_addr.o3 = resp[c+2];
sarahmarshy 0:fff4b9055396 229 adr.sin_addr.o4 = 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 }