Library to resolve text URLs to IP addresses (IPv4)
Dependents: NetworkSocketAPI NetworkSocketAPI Nucleo-AWS-IoT-mbed
DnsQuery.cpp@7:cbe1ef566314, 2016-02-23 (annotated)
- Committer:
- Christopher Haster
- Date:
- Tue Feb 23 01:24:53 2016 -0600
- Branch:
- api-changes
- Revision:
- 7:cbe1ef566314
- Parent:
- 6:5b28cbc8169c
- Child:
- 9:16e5208cc4ef
Added check for IP addresses
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 "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 | |
Christopher Haster |
5:d85c1a7e0e9f | 41 | DnsQuery::DnsQuery(UDPSocket *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 |
7:cbe1ef566314 | 49 | if (isIP(hostname)) { |
Christopher Haster |
7:cbe1ef566314 | 50 | strcpy(resolvedIp, hostname); |
Christopher Haster |
7:cbe1ef566314 | 51 | return true; |
Christopher Haster |
7:cbe1ef566314 | 52 | } |
Christopher Haster |
7:cbe1ef566314 | 53 | |
Christopher Haster |
4:3749346dcd59 | 54 | const char * dnsIPs[] = { |
sarahmarshy | 2:12d08f0f20cf | 55 | "8.8.8.8", |
sarahmarshy | 2:12d08f0f20cf | 56 | "209.244.0.3", |
sarahmarshy | 2:12d08f0f20cf | 57 | "84.200.69.80", |
sarahmarshy | 2:12d08f0f20cf | 58 | "8.26.56.26", |
sarahmarshy | 2:12d08f0f20cf | 59 | "208.67.222.222" |
sarahmarshy | 2:12d08f0f20cf | 60 | }; |
sarahmarshy | 0:fff4b9055396 | 61 | for(int i = 0; i<5; i++){ |
sarahmarshy | 2:12d08f0f20cf | 62 | _dnsip = dnsIPs[i]; |
sarahmarshy | 2:12d08f0f20cf | 63 | if(this->getIP(hostname, resolvedIp)){ |
sarahmarshy | 0:fff4b9055396 | 64 | return true; |
sarahmarshy | 0:fff4b9055396 | 65 | } |
sarahmarshy | 0:fff4b9055396 | 66 | |
sarahmarshy | 0:fff4b9055396 | 67 | } |
sarahmarshy | 0:fff4b9055396 | 68 | return false; |
sarahmarshy | 0:fff4b9055396 | 69 | |
sarahmarshy | 0:fff4b9055396 | 70 | } |
sarahmarshy | 0:fff4b9055396 | 71 | |
Christopher Haster |
7:cbe1ef566314 | 72 | bool DnsQuery::isIP(const char* hostname) const |
Christopher Haster |
7:cbe1ef566314 | 73 | { |
Christopher Haster |
7:cbe1ef566314 | 74 | int i; |
Christopher Haster |
7:cbe1ef566314 | 75 | |
Christopher Haster |
7:cbe1ef566314 | 76 | for (i = 0; hostname[i]; i++) { |
Christopher Haster |
7:cbe1ef566314 | 77 | if (!(hostname[i] >= '0' && hostname[i] <= '9') && hostname[i] != '.') { |
Christopher Haster |
7:cbe1ef566314 | 78 | return false; |
Christopher Haster |
7:cbe1ef566314 | 79 | } |
Christopher Haster |
7:cbe1ef566314 | 80 | } |
Christopher Haster |
7:cbe1ef566314 | 81 | |
Christopher Haster |
7:cbe1ef566314 | 82 | // Ending with '.' garuntees hostname |
Christopher Haster |
7:cbe1ef566314 | 83 | if (i > 0 && hostname[i-1] == '.') { |
Christopher Haster |
7:cbe1ef566314 | 84 | return false; |
Christopher Haster |
7:cbe1ef566314 | 85 | } |
Christopher Haster |
7:cbe1ef566314 | 86 | |
Christopher Haster |
7:cbe1ef566314 | 87 | return true; |
Christopher Haster |
7:cbe1ef566314 | 88 | } |
Christopher Haster |
7:cbe1ef566314 | 89 | |
sarahmarshy | 2:12d08f0f20cf | 90 | bool DnsQuery::getIP(const char* hostname, char* ipaddress) |
sarahmarshy | 0:fff4b9055396 | 91 | { |
sarahmarshy | 0:fff4b9055396 | 92 | INFO("%s", hostname); |
sarahmarshy | 0:fff4b9055396 | 93 | int len = 0; |
sarahmarshy | 0:fff4b9055396 | 94 | if (hostname == NULL) |
sarahmarshy | 0:fff4b9055396 | 95 | return false; |
sarahmarshy | 0:fff4b9055396 | 96 | len = strlen(hostname); |
sarahmarshy | 0:fff4b9055396 | 97 | if ((len >128) || (len == 0)) |
sarahmarshy | 0:fff4b9055396 | 98 | return false; |
sarahmarshy | 0:fff4b9055396 | 99 | |
sarahmarshy | 0:fff4b9055396 | 100 | int packetlen = /* size of HEADER structure */ 12 + /* size of QUESTION Structure */5 + len + 1; |
sarahmarshy | 0:fff4b9055396 | 101 | char *packet = new char[packetlen]; /* this is the UDP packet to send to the DNS */ |
sarahmarshy | 0:fff4b9055396 | 102 | if (packet == NULL) |
sarahmarshy | 0:fff4b9055396 | 103 | return false; |
sarahmarshy | 0:fff4b9055396 | 104 | |
sarahmarshy | 0:fff4b9055396 | 105 | // Fill the header |
sarahmarshy | 0:fff4b9055396 | 106 | memset(packet, 0, packetlen); |
sarahmarshy | 0:fff4b9055396 | 107 | packet[1] = 1; // ID = 1 |
sarahmarshy | 0:fff4b9055396 | 108 | packet[5] = 1; // QDCOUNT = 1 (contains one question) |
sarahmarshy | 0:fff4b9055396 | 109 | packet[2] = 1; // recursion requested |
sarahmarshy | 0:fff4b9055396 | 110 | |
sarahmarshy | 0:fff4b9055396 | 111 | int c = 13; // point to NAME element in question section or request |
sarahmarshy | 0:fff4b9055396 | 112 | int cnt = 12; // points to the counter of |
sarahmarshy | 0:fff4b9055396 | 113 | packet[cnt] = 0; |
sarahmarshy | 0:fff4b9055396 | 114 | for (int i = 0 ; i < len ; i++) { |
sarahmarshy | 0:fff4b9055396 | 115 | if (hostname[i] != '.') { |
sarahmarshy | 0:fff4b9055396 | 116 | // Copy the character and increment the character counter |
sarahmarshy | 0:fff4b9055396 | 117 | packet[cnt]++; |
sarahmarshy | 0:fff4b9055396 | 118 | packet[c++] = hostname[i]; |
sarahmarshy | 0:fff4b9055396 | 119 | } else { |
sarahmarshy | 0:fff4b9055396 | 120 | // Finished with this part, so go to the next |
sarahmarshy | 0:fff4b9055396 | 121 | cnt = c++; |
sarahmarshy | 0:fff4b9055396 | 122 | packet[cnt] = 0; |
sarahmarshy | 0:fff4b9055396 | 123 | } |
sarahmarshy | 0:fff4b9055396 | 124 | } |
sarahmarshy | 0:fff4b9055396 | 125 | |
sarahmarshy | 0:fff4b9055396 | 126 | // Terminate this domain name with a zero entry |
sarahmarshy | 0:fff4b9055396 | 127 | packet[c++] = 0; |
sarahmarshy | 0:fff4b9055396 | 128 | |
sarahmarshy | 0:fff4b9055396 | 129 | // Set QTYPE |
sarahmarshy | 0:fff4b9055396 | 130 | packet[c++] = 0; |
sarahmarshy | 0:fff4b9055396 | 131 | packet[c++] = 1; |
sarahmarshy | 0:fff4b9055396 | 132 | // Set QCLASS |
sarahmarshy | 0:fff4b9055396 | 133 | packet[c++] = 0; |
sarahmarshy | 0:fff4b9055396 | 134 | packet[c++] = 1; |
sarahmarshy | 0:fff4b9055396 | 135 | |
sarahmarshy | 0:fff4b9055396 | 136 | |
sarahmarshy | 0:fff4b9055396 | 137 | // Ready to send to DNS |
Christopher Haster |
6:5b28cbc8169c | 138 | socket->open(_dnsip, 53); |
sarahmarshy | 0:fff4b9055396 | 139 | |
sarahmarshy | 1:5d978992a518 | 140 | INFO("Sending packet of length %d",packetlen); |
sarahmarshy | 1:5d978992a518 | 141 | /* |
sarahmarshy | 1:5d978992a518 | 142 | for( int i = 0 ; i < c ; i++) { |
sarahmarshy | 1:5d978992a518 | 143 | printf("%02x ", packet[i]); |
sarahmarshy | 1:5d978992a518 | 144 | } |
sarahmarshy | 1:5d978992a518 | 145 | */ |
sarahmarshy | 1:5d978992a518 | 146 | if (socket->send(packet, packetlen) < 0) { |
sarahmarshy | 0:fff4b9055396 | 147 | delete packet; |
sarahmarshy | 0:fff4b9055396 | 148 | return false; |
sarahmarshy | 0:fff4b9055396 | 149 | } |
sarahmarshy | 0:fff4b9055396 | 150 | delete packet; |
sarahmarshy | 0:fff4b9055396 | 151 | |
sarahmarshy | 0:fff4b9055396 | 152 | packet = new char [1024]; |
sarahmarshy | 0:fff4b9055396 | 153 | |
sarahmarshy | 0:fff4b9055396 | 154 | // Receive the answer from DNS |
sarahmarshy | 0:fff4b9055396 | 155 | int response_length = 0; |
sarahmarshy | 2:12d08f0f20cf | 156 | INFO("Recieving"); |
sarahmarshy | 2:12d08f0f20cf | 157 | response_length = socket->recv(packet, 1024); |
sarahmarshy | 1:5d978992a518 | 158 | /* |
sarahmarshy | 1:5d978992a518 | 159 | for( int i = 0 ; i < 1024; i++) { |
sarahmarshy | 1:5d978992a518 | 160 | printf("%02x ", packet[i]); |
sarahmarshy | 1:5d978992a518 | 161 | } |
sarahmarshy | 1:5d978992a518 | 162 | */ |
sarahmarshy | 2:12d08f0f20cf | 163 | if (response_length > 0 ) { |
sarahmarshy | 2:12d08f0f20cf | 164 | if (!resolve(packet, ipaddress)) { |
sarahmarshy | 2:12d08f0f20cf | 165 | socket->close(); |
sarahmarshy | 0:fff4b9055396 | 166 | delete packet; |
sarahmarshy | 2:12d08f0f20cf | 167 | ERR("NO IP FOUND\n"); |
sarahmarshy | 2:12d08f0f20cf | 168 | return false; |
sarahmarshy | 0:fff4b9055396 | 169 | } |
sarahmarshy | 2:12d08f0f20cf | 170 | |
sarahmarshy | 2:12d08f0f20cf | 171 | // cleanup and return |
sarahmarshy | 2:12d08f0f20cf | 172 | delete packet; |
sarahmarshy | 2:12d08f0f20cf | 173 | socket->close(); |
sarahmarshy | 2:12d08f0f20cf | 174 | return true; |
sarahmarshy | 2:12d08f0f20cf | 175 | } else { |
sarahmarshy | 2:12d08f0f20cf | 176 | ERR("SocketRecvFrom returned %d !", response_length); |
sarahmarshy | 2:12d08f0f20cf | 177 | } |
sarahmarshy | 1:5d978992a518 | 178 | socket->close(); |
sarahmarshy | 0:fff4b9055396 | 179 | delete packet; |
sarahmarshy | 0:fff4b9055396 | 180 | ERR("NO IP FOUND\n"); |
sarahmarshy | 0:fff4b9055396 | 181 | return false; |
sarahmarshy | 0:fff4b9055396 | 182 | } |
sarahmarshy | 0:fff4b9055396 | 183 | |
sarahmarshy | 0:fff4b9055396 | 184 | |
sarahmarshy | 2:12d08f0f20cf | 185 | bool DnsQuery::resolve(char* resp, char* ipaddress) |
sarahmarshy | 0:fff4b9055396 | 186 | { |
sarahmarshy | 0:fff4b9055396 | 187 | |
sarahmarshy | 0:fff4b9055396 | 188 | int ID = (((int)resp[0]) <<8) + resp[1]; |
sarahmarshy | 0:fff4b9055396 | 189 | int QR = resp[2] >>7; |
sarahmarshy | 0:fff4b9055396 | 190 | int Opcode = (resp[2]>>3) & 0x0F; |
sarahmarshy | 0:fff4b9055396 | 191 | int RCODE = (resp[3] & 0x0F); |
sarahmarshy | 0:fff4b9055396 | 192 | int ANCOUNT = (((int)resp[6])<<8)+ resp[7]; |
sarahmarshy | 0:fff4b9055396 | 193 | |
sarahmarshy | 0:fff4b9055396 | 194 | INFO("Resolving response : ID = %d, QR = %d, Opcode = %d, RCODE = %d", ID, QR, Opcode, RCODE); |
sarahmarshy | 0:fff4b9055396 | 195 | if ((ID != 1) || (QR != 1) || (Opcode != 0) || (RCODE != 0)) { |
sarahmarshy | 0:fff4b9055396 | 196 | ERR("Received non matching response from DNS !"); |
sarahmarshy | 0:fff4b9055396 | 197 | return false; |
sarahmarshy | 0:fff4b9055396 | 198 | } |
sarahmarshy | 0:fff4b9055396 | 199 | |
sarahmarshy | 0:fff4b9055396 | 200 | int c = 12; |
sarahmarshy | 0:fff4b9055396 | 201 | int d; |
sarahmarshy | 0:fff4b9055396 | 202 | // Skip domain question |
sarahmarshy | 0:fff4b9055396 | 203 | while( (d=resp[c++]) != 0) { |
sarahmarshy | 0:fff4b9055396 | 204 | c+=d; |
sarahmarshy | 0:fff4b9055396 | 205 | } |
sarahmarshy | 0:fff4b9055396 | 206 | c+= 4; // skip QTYPE and QCLASS |
sarahmarshy | 0:fff4b9055396 | 207 | |
sarahmarshy | 0:fff4b9055396 | 208 | // Here comes the resource record |
sarahmarshy | 0:fff4b9055396 | 209 | for (int ans = 0 ; ans < ANCOUNT; ans++) { |
sarahmarshy | 0:fff4b9055396 | 210 | if (parseRR(resp, c, ipaddress)) { |
sarahmarshy | 0:fff4b9055396 | 211 | return true; |
sarahmarshy | 0:fff4b9055396 | 212 | } |
sarahmarshy | 0:fff4b9055396 | 213 | } |
sarahmarshy | 0:fff4b9055396 | 214 | |
sarahmarshy | 0:fff4b9055396 | 215 | return false; |
sarahmarshy | 0:fff4b9055396 | 216 | } |
sarahmarshy | 0:fff4b9055396 | 217 | |
sarahmarshy | 2:12d08f0f20cf | 218 | bool DnsQuery::parseRR(char *resp, int& c, char* adr ) |
sarahmarshy | 0:fff4b9055396 | 219 | { |
sarahmarshy | 0:fff4b9055396 | 220 | int n = 0; |
sarahmarshy | 0:fff4b9055396 | 221 | while( (n=resp[c++]) != 0) { |
sarahmarshy | 0:fff4b9055396 | 222 | if ((n & 0xc0) != 0) { |
sarahmarshy | 0:fff4b9055396 | 223 | // This is a link |
sarahmarshy | 0:fff4b9055396 | 224 | c++; |
sarahmarshy | 0:fff4b9055396 | 225 | break; |
sarahmarshy | 0:fff4b9055396 | 226 | } else { |
sarahmarshy | 0:fff4b9055396 | 227 | c+= n; // skip this segment, not interested in string domain names |
sarahmarshy | 0:fff4b9055396 | 228 | } |
sarahmarshy | 0:fff4b9055396 | 229 | } |
sarahmarshy | 0:fff4b9055396 | 230 | |
sarahmarshy | 0:fff4b9055396 | 231 | int TYPE = (((int)resp[c])<<8) + resp[c+1]; |
sarahmarshy | 0:fff4b9055396 | 232 | int CLASS = (((int)resp[c+2])<<8) + resp[c+3]; |
sarahmarshy | 0:fff4b9055396 | 233 | int RDLENGTH = (((int)resp[c+8])<<8) + resp[c+9]; |
sarahmarshy | 0:fff4b9055396 | 234 | |
sarahmarshy | 0:fff4b9055396 | 235 | INFO("Record of TYPE=%d and CLASS=%d detected !", TYPE, CLASS); |
sarahmarshy | 0:fff4b9055396 | 236 | c+= 10; |
sarahmarshy | 0:fff4b9055396 | 237 | if ((CLASS == 1) && (TYPE == 1)) { |
sarahmarshy | 2:12d08f0f20cf | 238 | sprintf(adr,"%d.%d.%d.%d", resp[c], resp[c+1], resp[c+2], resp[c+3]); |
sarahmarshy | 0:fff4b9055396 | 239 | c+= RDLENGTH; |
sarahmarshy | 0:fff4b9055396 | 240 | return true; |
sarahmarshy | 0:fff4b9055396 | 241 | } else { |
sarahmarshy | 0:fff4b9055396 | 242 | } |
sarahmarshy | 0:fff4b9055396 | 243 | c+= RDLENGTH; |
sarahmarshy | 0:fff4b9055396 | 244 | |
sarahmarshy | 0:fff4b9055396 | 245 | return false; |
Christopher Haster |
4:3749346dcd59 | 246 | } |