Library to resolve text URLs to IP addresses (IPv4)
Dependents: NetworkSocketAPI NetworkSocketAPI Nucleo-AWS-IoT-mbed
DnsQuery.cpp@3:5705fdae6185, 2015-08-27 (annotated)
- Committer:
- sarahmarshy
- Date:
- Thu Aug 27 14:33:07 2015 +0000
- Revision:
- 3:5705fdae6185
- Parent:
- 2:12d08f0f20cf
- Child:
- 4:3749346dcd59
Constructor calls gethostbyname;
Who changed what in which revision?
User | Revision | Line number | New 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 | 3:5705fdae6185 | 40 | DnsQuery::DnsQuery(SocketInterface *sock,const char* hostname, char* ipaddress) |
sarahmarshy | 0:fff4b9055396 | 41 | { |
sarahmarshy | 1:5d978992a518 | 42 | socket = sock; |
sarahmarshy | 3:5705fdae6185 | 43 | this->getHostByName(hostname, ipaddress); |
sarahmarshy | 0:fff4b9055396 | 44 | } |
sarahmarshy | 0:fff4b9055396 | 45 | |
sarahmarshy | 3:5705fdae6185 | 46 | bool DnsQuery::getHostByName(const char* hostname, char* resolvedIp) |
sarahmarshy | 0:fff4b9055396 | 47 | { |
sarahmarshy | 2:12d08f0f20cf | 48 | char * dnsIPs[] = { |
sarahmarshy | 2:12d08f0f20cf | 49 | "8.8.8.8", |
sarahmarshy | 2:12d08f0f20cf | 50 | "209.244.0.3", |
sarahmarshy | 2:12d08f0f20cf | 51 | "84.200.69.80", |
sarahmarshy | 2:12d08f0f20cf | 52 | "8.26.56.26", |
sarahmarshy | 2:12d08f0f20cf | 53 | "208.67.222.222" |
sarahmarshy | 2:12d08f0f20cf | 54 | }; |
sarahmarshy | 0:fff4b9055396 | 55 | for(int i = 0; i<5; i++){ |
sarahmarshy | 2:12d08f0f20cf | 56 | _dnsip = dnsIPs[i]; |
sarahmarshy | 2:12d08f0f20cf | 57 | if(this->getIP(hostname, resolvedIp)){ |
sarahmarshy | 0:fff4b9055396 | 58 | return true; |
sarahmarshy | 0:fff4b9055396 | 59 | } |
sarahmarshy | 0:fff4b9055396 | 60 | |
sarahmarshy | 0:fff4b9055396 | 61 | } |
sarahmarshy | 0:fff4b9055396 | 62 | return false; |
sarahmarshy | 0:fff4b9055396 | 63 | |
sarahmarshy | 0:fff4b9055396 | 64 | } |
sarahmarshy | 0:fff4b9055396 | 65 | |
sarahmarshy | 2:12d08f0f20cf | 66 | bool DnsQuery::getIP(const char* hostname, char* ipaddress) |
sarahmarshy | 0:fff4b9055396 | 67 | { |
sarahmarshy | 0:fff4b9055396 | 68 | INFO("%s", hostname); |
sarahmarshy | 0:fff4b9055396 | 69 | int len = 0; |
sarahmarshy | 0:fff4b9055396 | 70 | if (hostname == NULL) |
sarahmarshy | 0:fff4b9055396 | 71 | return false; |
sarahmarshy | 0:fff4b9055396 | 72 | len = strlen(hostname); |
sarahmarshy | 0:fff4b9055396 | 73 | if ((len >128) || (len == 0)) |
sarahmarshy | 0:fff4b9055396 | 74 | return false; |
sarahmarshy | 0:fff4b9055396 | 75 | |
sarahmarshy | 0:fff4b9055396 | 76 | int packetlen = /* size of HEADER structure */ 12 + /* size of QUESTION Structure */5 + len + 1; |
sarahmarshy | 0:fff4b9055396 | 77 | char *packet = new char[packetlen]; /* this is the UDP packet to send to the DNS */ |
sarahmarshy | 0:fff4b9055396 | 78 | if (packet == NULL) |
sarahmarshy | 0:fff4b9055396 | 79 | return false; |
sarahmarshy | 0:fff4b9055396 | 80 | |
sarahmarshy | 0:fff4b9055396 | 81 | // Fill the header |
sarahmarshy | 0:fff4b9055396 | 82 | memset(packet, 0, packetlen); |
sarahmarshy | 0:fff4b9055396 | 83 | packet[1] = 1; // ID = 1 |
sarahmarshy | 0:fff4b9055396 | 84 | packet[5] = 1; // QDCOUNT = 1 (contains one question) |
sarahmarshy | 0:fff4b9055396 | 85 | packet[2] = 1; // recursion requested |
sarahmarshy | 0:fff4b9055396 | 86 | |
sarahmarshy | 0:fff4b9055396 | 87 | int c = 13; // point to NAME element in question section or request |
sarahmarshy | 0:fff4b9055396 | 88 | int cnt = 12; // points to the counter of |
sarahmarshy | 0:fff4b9055396 | 89 | packet[cnt] = 0; |
sarahmarshy | 0:fff4b9055396 | 90 | for (int i = 0 ; i < len ; i++) { |
sarahmarshy | 0:fff4b9055396 | 91 | if (hostname[i] != '.') { |
sarahmarshy | 0:fff4b9055396 | 92 | // Copy the character and increment the character counter |
sarahmarshy | 0:fff4b9055396 | 93 | packet[cnt]++; |
sarahmarshy | 0:fff4b9055396 | 94 | packet[c++] = hostname[i]; |
sarahmarshy | 0:fff4b9055396 | 95 | } else { |
sarahmarshy | 0:fff4b9055396 | 96 | // Finished with this part, so go to the next |
sarahmarshy | 0:fff4b9055396 | 97 | cnt = c++; |
sarahmarshy | 0:fff4b9055396 | 98 | packet[cnt] = 0; |
sarahmarshy | 0:fff4b9055396 | 99 | } |
sarahmarshy | 0:fff4b9055396 | 100 | } |
sarahmarshy | 0:fff4b9055396 | 101 | |
sarahmarshy | 0:fff4b9055396 | 102 | // Terminate this domain name with a zero entry |
sarahmarshy | 0:fff4b9055396 | 103 | packet[c++] = 0; |
sarahmarshy | 0:fff4b9055396 | 104 | |
sarahmarshy | 0:fff4b9055396 | 105 | // Set QTYPE |
sarahmarshy | 0:fff4b9055396 | 106 | packet[c++] = 0; |
sarahmarshy | 0:fff4b9055396 | 107 | packet[c++] = 1; |
sarahmarshy | 0:fff4b9055396 | 108 | // Set QCLASS |
sarahmarshy | 0:fff4b9055396 | 109 | packet[c++] = 0; |
sarahmarshy | 0:fff4b9055396 | 110 | packet[c++] = 1; |
sarahmarshy | 0:fff4b9055396 | 111 | |
sarahmarshy | 0:fff4b9055396 | 112 | |
sarahmarshy | 0:fff4b9055396 | 113 | // Ready to send to DNS |
sarahmarshy | 2:12d08f0f20cf | 114 | socket->setAddressPort(_dnsip, 53); |
sarahmarshy | 1:5d978992a518 | 115 | socket->open(); |
sarahmarshy | 0:fff4b9055396 | 116 | |
sarahmarshy | 1:5d978992a518 | 117 | INFO("Sending packet of length %d",packetlen); |
sarahmarshy | 1:5d978992a518 | 118 | /* |
sarahmarshy | 1:5d978992a518 | 119 | for( int i = 0 ; i < c ; i++) { |
sarahmarshy | 1:5d978992a518 | 120 | printf("%02x ", packet[i]); |
sarahmarshy | 1:5d978992a518 | 121 | } |
sarahmarshy | 1:5d978992a518 | 122 | */ |
sarahmarshy | 1:5d978992a518 | 123 | if (socket->send(packet, packetlen) < 0) { |
sarahmarshy | 0:fff4b9055396 | 124 | delete packet; |
sarahmarshy | 0:fff4b9055396 | 125 | return false; |
sarahmarshy | 0:fff4b9055396 | 126 | } |
sarahmarshy | 0:fff4b9055396 | 127 | delete packet; |
sarahmarshy | 0:fff4b9055396 | 128 | |
sarahmarshy | 0:fff4b9055396 | 129 | packet = new char [1024]; |
sarahmarshy | 0:fff4b9055396 | 130 | |
sarahmarshy | 0:fff4b9055396 | 131 | // Receive the answer from DNS |
sarahmarshy | 0:fff4b9055396 | 132 | int response_length = 0; |
sarahmarshy | 2:12d08f0f20cf | 133 | INFO("Recieving"); |
sarahmarshy | 2:12d08f0f20cf | 134 | response_length = socket->recv(packet, 1024); |
sarahmarshy | 1:5d978992a518 | 135 | /* |
sarahmarshy | 1:5d978992a518 | 136 | for( int i = 0 ; i < 1024; i++) { |
sarahmarshy | 1:5d978992a518 | 137 | printf("%02x ", packet[i]); |
sarahmarshy | 1:5d978992a518 | 138 | } |
sarahmarshy | 1:5d978992a518 | 139 | */ |
sarahmarshy | 2:12d08f0f20cf | 140 | if (response_length > 0 ) { |
sarahmarshy | 2:12d08f0f20cf | 141 | if (!resolve(packet, ipaddress)) { |
sarahmarshy | 2:12d08f0f20cf | 142 | socket->close(); |
sarahmarshy | 0:fff4b9055396 | 143 | delete packet; |
sarahmarshy | 2:12d08f0f20cf | 144 | ERR("NO IP FOUND\n"); |
sarahmarshy | 2:12d08f0f20cf | 145 | return false; |
sarahmarshy | 0:fff4b9055396 | 146 | } |
sarahmarshy | 2:12d08f0f20cf | 147 | |
sarahmarshy | 2:12d08f0f20cf | 148 | // cleanup and return |
sarahmarshy | 2:12d08f0f20cf | 149 | delete packet; |
sarahmarshy | 2:12d08f0f20cf | 150 | socket->close(); |
sarahmarshy | 2:12d08f0f20cf | 151 | return true; |
sarahmarshy | 2:12d08f0f20cf | 152 | } else { |
sarahmarshy | 2:12d08f0f20cf | 153 | ERR("SocketRecvFrom returned %d !", response_length); |
sarahmarshy | 2:12d08f0f20cf | 154 | } |
sarahmarshy | 1:5d978992a518 | 155 | socket->close(); |
sarahmarshy | 0:fff4b9055396 | 156 | delete packet; |
sarahmarshy | 0:fff4b9055396 | 157 | ERR("NO IP FOUND\n"); |
sarahmarshy | 0:fff4b9055396 | 158 | return false; |
sarahmarshy | 0:fff4b9055396 | 159 | } |
sarahmarshy | 0:fff4b9055396 | 160 | |
sarahmarshy | 0:fff4b9055396 | 161 | |
sarahmarshy | 2:12d08f0f20cf | 162 | bool DnsQuery::resolve(char* resp, char* ipaddress) |
sarahmarshy | 0:fff4b9055396 | 163 | { |
sarahmarshy | 0:fff4b9055396 | 164 | |
sarahmarshy | 0:fff4b9055396 | 165 | int ID = (((int)resp[0]) <<8) + resp[1]; |
sarahmarshy | 0:fff4b9055396 | 166 | int QR = resp[2] >>7; |
sarahmarshy | 0:fff4b9055396 | 167 | int Opcode = (resp[2]>>3) & 0x0F; |
sarahmarshy | 0:fff4b9055396 | 168 | int RCODE = (resp[3] & 0x0F); |
sarahmarshy | 0:fff4b9055396 | 169 | int ANCOUNT = (((int)resp[6])<<8)+ resp[7]; |
sarahmarshy | 0:fff4b9055396 | 170 | |
sarahmarshy | 0:fff4b9055396 | 171 | INFO("Resolving response : ID = %d, QR = %d, Opcode = %d, RCODE = %d", ID, QR, Opcode, RCODE); |
sarahmarshy | 0:fff4b9055396 | 172 | if ((ID != 1) || (QR != 1) || (Opcode != 0) || (RCODE != 0)) { |
sarahmarshy | 0:fff4b9055396 | 173 | ERR("Received non matching response from DNS !"); |
sarahmarshy | 0:fff4b9055396 | 174 | return false; |
sarahmarshy | 0:fff4b9055396 | 175 | } |
sarahmarshy | 0:fff4b9055396 | 176 | |
sarahmarshy | 0:fff4b9055396 | 177 | int c = 12; |
sarahmarshy | 0:fff4b9055396 | 178 | int d; |
sarahmarshy | 0:fff4b9055396 | 179 | // Skip domain question |
sarahmarshy | 0:fff4b9055396 | 180 | while( (d=resp[c++]) != 0) { |
sarahmarshy | 0:fff4b9055396 | 181 | c+=d; |
sarahmarshy | 0:fff4b9055396 | 182 | } |
sarahmarshy | 0:fff4b9055396 | 183 | c+= 4; // skip QTYPE and QCLASS |
sarahmarshy | 0:fff4b9055396 | 184 | |
sarahmarshy | 0:fff4b9055396 | 185 | // Here comes the resource record |
sarahmarshy | 0:fff4b9055396 | 186 | for (int ans = 0 ; ans < ANCOUNT; ans++) { |
sarahmarshy | 0:fff4b9055396 | 187 | if (parseRR(resp, c, ipaddress)) { |
sarahmarshy | 0:fff4b9055396 | 188 | return true; |
sarahmarshy | 0:fff4b9055396 | 189 | } |
sarahmarshy | 0:fff4b9055396 | 190 | } |
sarahmarshy | 0:fff4b9055396 | 191 | |
sarahmarshy | 0:fff4b9055396 | 192 | return false; |
sarahmarshy | 0:fff4b9055396 | 193 | } |
sarahmarshy | 0:fff4b9055396 | 194 | |
sarahmarshy | 2:12d08f0f20cf | 195 | bool DnsQuery::parseRR(char *resp, int& c, char* adr ) |
sarahmarshy | 0:fff4b9055396 | 196 | { |
sarahmarshy | 0:fff4b9055396 | 197 | int n = 0; |
sarahmarshy | 0:fff4b9055396 | 198 | while( (n=resp[c++]) != 0) { |
sarahmarshy | 0:fff4b9055396 | 199 | if ((n & 0xc0) != 0) { |
sarahmarshy | 0:fff4b9055396 | 200 | // This is a link |
sarahmarshy | 0:fff4b9055396 | 201 | c++; |
sarahmarshy | 0:fff4b9055396 | 202 | break; |
sarahmarshy | 0:fff4b9055396 | 203 | } else { |
sarahmarshy | 0:fff4b9055396 | 204 | c+= n; // skip this segment, not interested in string domain names |
sarahmarshy | 0:fff4b9055396 | 205 | } |
sarahmarshy | 0:fff4b9055396 | 206 | } |
sarahmarshy | 0:fff4b9055396 | 207 | |
sarahmarshy | 0:fff4b9055396 | 208 | int TYPE = (((int)resp[c])<<8) + resp[c+1]; |
sarahmarshy | 0:fff4b9055396 | 209 | int CLASS = (((int)resp[c+2])<<8) + resp[c+3]; |
sarahmarshy | 0:fff4b9055396 | 210 | int RDLENGTH = (((int)resp[c+8])<<8) + resp[c+9]; |
sarahmarshy | 0:fff4b9055396 | 211 | |
sarahmarshy | 0:fff4b9055396 | 212 | INFO("Record of TYPE=%d and CLASS=%d detected !", TYPE, CLASS); |
sarahmarshy | 0:fff4b9055396 | 213 | c+= 10; |
sarahmarshy | 0:fff4b9055396 | 214 | if ((CLASS == 1) && (TYPE == 1)) { |
sarahmarshy | 2:12d08f0f20cf | 215 | sprintf(adr,"%d.%d.%d.%d", resp[c], resp[c+1], resp[c+2], resp[c+3]); |
sarahmarshy | 0:fff4b9055396 | 216 | c+= RDLENGTH; |
sarahmarshy | 0:fff4b9055396 | 217 | return true; |
sarahmarshy | 0:fff4b9055396 | 218 | } else { |
sarahmarshy | 0:fff4b9055396 | 219 | } |
sarahmarshy | 0:fff4b9055396 | 220 | c+= RDLENGTH; |
sarahmarshy | 0:fff4b9055396 | 221 | |
sarahmarshy | 0:fff4b9055396 | 222 | return false; |
sarahmarshy | 0:fff4b9055396 | 223 | } |