UIPEthernet library for Arduino IDE, Eclipse with arduino plugin and MBED/SMeshStudio (AVR,STM32F,ESP8266,Intel ARC32,Nordic nRF51,Teensy boards,Realtek Ameba(RTL8195A,RTL8710)), ENC28j60 network chip. Compatible with Wiznet W5100 Ethernet library API. Compiled and tested on Nucleo-F302R8. Master repository is: https://github.com/UIPEthernet/UIPEthernet/
Dns.cpp@0:e3fb1267e3c3, 2016-12-21 (annotated)
- Committer:
- cassyarduino
- Date:
- Wed Dec 21 16:58:10 2016 +0100
- Revision:
- 0:e3fb1267e3c3
- Child:
- 9:312e0937630f
initial release
Who changed what in which revision?
User | Revision | Line number | New contents of line |
---|---|---|---|
cassyarduino | 0:e3fb1267e3c3 | 1 | // Arduino DNS client for Enc28J60-based Ethernet shield |
cassyarduino | 0:e3fb1267e3c3 | 2 | // (c) Copyright 2009-2010 MCQN Ltd. |
cassyarduino | 0:e3fb1267e3c3 | 3 | // Released under Apache License, version 2.0 |
cassyarduino | 0:e3fb1267e3c3 | 4 | |
cassyarduino | 0:e3fb1267e3c3 | 5 | #include "Dns.h" |
cassyarduino | 0:e3fb1267e3c3 | 6 | #include <string.h> |
cassyarduino | 0:e3fb1267e3c3 | 7 | //#include <stdlib.h> |
cassyarduino | 0:e3fb1267e3c3 | 8 | #if defined(ARDUINO) |
cassyarduino | 0:e3fb1267e3c3 | 9 | #include "Arduino.h" |
cassyarduino | 0:e3fb1267e3c3 | 10 | #include "Udp.h" |
cassyarduino | 0:e3fb1267e3c3 | 11 | #endif |
cassyarduino | 0:e3fb1267e3c3 | 12 | #if defined(__MBED__) |
cassyarduino | 0:e3fb1267e3c3 | 13 | #include <mbed.h> |
cassyarduino | 0:e3fb1267e3c3 | 14 | #include "mbed/Udp.h" |
cassyarduino | 0:e3fb1267e3c3 | 15 | #include "mbed/millis.h" |
cassyarduino | 0:e3fb1267e3c3 | 16 | #define delay(x) wait_ms(x) |
cassyarduino | 0:e3fb1267e3c3 | 17 | #endif |
cassyarduino | 0:e3fb1267e3c3 | 18 | #include "utility/logging.h" |
cassyarduino | 0:e3fb1267e3c3 | 19 | #include "utility/uip.h" |
cassyarduino | 0:e3fb1267e3c3 | 20 | |
cassyarduino | 0:e3fb1267e3c3 | 21 | |
cassyarduino | 0:e3fb1267e3c3 | 22 | #define SOCKET_NONE 255 |
cassyarduino | 0:e3fb1267e3c3 | 23 | // Various flags and header field values for a DNS message |
cassyarduino | 0:e3fb1267e3c3 | 24 | #define UDP_HEADER_SIZE 8 |
cassyarduino | 0:e3fb1267e3c3 | 25 | #define DNS_HEADER_SIZE 12 |
cassyarduino | 0:e3fb1267e3c3 | 26 | #define TTL_SIZE 4 |
cassyarduino | 0:e3fb1267e3c3 | 27 | #define QUERY_FLAG (0) |
cassyarduino | 0:e3fb1267e3c3 | 28 | #define RESPONSE_FLAG (1<<15) |
cassyarduino | 0:e3fb1267e3c3 | 29 | #define QUERY_RESPONSE_MASK (1<<15) |
cassyarduino | 0:e3fb1267e3c3 | 30 | #define OPCODE_STANDARD_QUERY (0) |
cassyarduino | 0:e3fb1267e3c3 | 31 | #define OPCODE_INVERSE_QUERY (1<<11) |
cassyarduino | 0:e3fb1267e3c3 | 32 | #define OPCODE_STATUS_REQUEST (2<<11) |
cassyarduino | 0:e3fb1267e3c3 | 33 | #define OPCODE_MASK (15<<11) |
cassyarduino | 0:e3fb1267e3c3 | 34 | #define AUTHORITATIVE_FLAG (1<<10) |
cassyarduino | 0:e3fb1267e3c3 | 35 | #define TRUNCATION_FLAG (1<<9) |
cassyarduino | 0:e3fb1267e3c3 | 36 | #define RECURSION_DESIRED_FLAG (1<<8) |
cassyarduino | 0:e3fb1267e3c3 | 37 | #define RECURSION_AVAILABLE_FLAG (1<<7) |
cassyarduino | 0:e3fb1267e3c3 | 38 | #define RESP_NO_ERROR (0) |
cassyarduino | 0:e3fb1267e3c3 | 39 | #define RESP_FORMAT_ERROR (1) |
cassyarduino | 0:e3fb1267e3c3 | 40 | #define RESP_SERVER_FAILURE (2) |
cassyarduino | 0:e3fb1267e3c3 | 41 | #define RESP_NAME_ERROR (3) |
cassyarduino | 0:e3fb1267e3c3 | 42 | #define RESP_NOT_IMPLEMENTED (4) |
cassyarduino | 0:e3fb1267e3c3 | 43 | #define RESP_REFUSED (5) |
cassyarduino | 0:e3fb1267e3c3 | 44 | #define RESP_MASK (15) |
cassyarduino | 0:e3fb1267e3c3 | 45 | #define TYPE_A (0x0001) |
cassyarduino | 0:e3fb1267e3c3 | 46 | #define CLASS_IN (0x0001) |
cassyarduino | 0:e3fb1267e3c3 | 47 | #define LABEL_COMPRESSION_MASK (0xC0) |
cassyarduino | 0:e3fb1267e3c3 | 48 | // Port number that DNS servers listen on |
cassyarduino | 0:e3fb1267e3c3 | 49 | #define DNS_PORT 53 |
cassyarduino | 0:e3fb1267e3c3 | 50 | |
cassyarduino | 0:e3fb1267e3c3 | 51 | // Possible return codes from ProcessResponse |
cassyarduino | 0:e3fb1267e3c3 | 52 | #define SUCCESS 1 |
cassyarduino | 0:e3fb1267e3c3 | 53 | #define TIMED_OUT -1 |
cassyarduino | 0:e3fb1267e3c3 | 54 | #define INVALID_SERVER -2 |
cassyarduino | 0:e3fb1267e3c3 | 55 | #define TRUNCATED -3 |
cassyarduino | 0:e3fb1267e3c3 | 56 | #define INVALID_RESPONSE -4 |
cassyarduino | 0:e3fb1267e3c3 | 57 | |
cassyarduino | 0:e3fb1267e3c3 | 58 | void DNSClient::begin(const IPAddress& aDNSServer) |
cassyarduino | 0:e3fb1267e3c3 | 59 | { |
cassyarduino | 0:e3fb1267e3c3 | 60 | iDNSServer = aDNSServer; |
cassyarduino | 0:e3fb1267e3c3 | 61 | iRequestId = 0; |
cassyarduino | 0:e3fb1267e3c3 | 62 | } |
cassyarduino | 0:e3fb1267e3c3 | 63 | |
cassyarduino | 0:e3fb1267e3c3 | 64 | |
cassyarduino | 0:e3fb1267e3c3 | 65 | int DNSClient::inet_aton(const char* aIPAddrString, IPAddress& aResult) |
cassyarduino | 0:e3fb1267e3c3 | 66 | { |
cassyarduino | 0:e3fb1267e3c3 | 67 | // See if we've been given a valid IP address |
cassyarduino | 0:e3fb1267e3c3 | 68 | const char* p =aIPAddrString; |
cassyarduino | 0:e3fb1267e3c3 | 69 | while (*p && ( (*p == '.') || ((*p >= '0') && (*p <= '9')) )) |
cassyarduino | 0:e3fb1267e3c3 | 70 | { |
cassyarduino | 0:e3fb1267e3c3 | 71 | p++; |
cassyarduino | 0:e3fb1267e3c3 | 72 | } |
cassyarduino | 0:e3fb1267e3c3 | 73 | |
cassyarduino | 0:e3fb1267e3c3 | 74 | if (*p == '\0') |
cassyarduino | 0:e3fb1267e3c3 | 75 | { |
cassyarduino | 0:e3fb1267e3c3 | 76 | // It's looking promising, we haven't found any invalid characters |
cassyarduino | 0:e3fb1267e3c3 | 77 | p = aIPAddrString; |
cassyarduino | 0:e3fb1267e3c3 | 78 | int segment =0; |
cassyarduino | 0:e3fb1267e3c3 | 79 | int segmentValue =0; |
cassyarduino | 0:e3fb1267e3c3 | 80 | while (*p && (segment < 4)) |
cassyarduino | 0:e3fb1267e3c3 | 81 | { |
cassyarduino | 0:e3fb1267e3c3 | 82 | if (*p == '.') |
cassyarduino | 0:e3fb1267e3c3 | 83 | { |
cassyarduino | 0:e3fb1267e3c3 | 84 | // We've reached the end of a segment |
cassyarduino | 0:e3fb1267e3c3 | 85 | if (segmentValue > 255) |
cassyarduino | 0:e3fb1267e3c3 | 86 | { |
cassyarduino | 0:e3fb1267e3c3 | 87 | // You can't have IP address segments that don't fit in a byte |
cassyarduino | 0:e3fb1267e3c3 | 88 | return 0; |
cassyarduino | 0:e3fb1267e3c3 | 89 | } |
cassyarduino | 0:e3fb1267e3c3 | 90 | else |
cassyarduino | 0:e3fb1267e3c3 | 91 | { |
cassyarduino | 0:e3fb1267e3c3 | 92 | aResult[segment] = (uint8_t)segmentValue; |
cassyarduino | 0:e3fb1267e3c3 | 93 | segment++; |
cassyarduino | 0:e3fb1267e3c3 | 94 | segmentValue = 0; |
cassyarduino | 0:e3fb1267e3c3 | 95 | } |
cassyarduino | 0:e3fb1267e3c3 | 96 | } |
cassyarduino | 0:e3fb1267e3c3 | 97 | else |
cassyarduino | 0:e3fb1267e3c3 | 98 | { |
cassyarduino | 0:e3fb1267e3c3 | 99 | // Next digit |
cassyarduino | 0:e3fb1267e3c3 | 100 | segmentValue = (segmentValue*10)+(*p - '0'); |
cassyarduino | 0:e3fb1267e3c3 | 101 | } |
cassyarduino | 0:e3fb1267e3c3 | 102 | p++; |
cassyarduino | 0:e3fb1267e3c3 | 103 | } |
cassyarduino | 0:e3fb1267e3c3 | 104 | // We've reached the end of address, but there'll still be the last |
cassyarduino | 0:e3fb1267e3c3 | 105 | // segment to deal with |
cassyarduino | 0:e3fb1267e3c3 | 106 | if ((segmentValue > 255) || (segment > 3)) |
cassyarduino | 0:e3fb1267e3c3 | 107 | { |
cassyarduino | 0:e3fb1267e3c3 | 108 | // You can't have IP address segments that don't fit in a byte, |
cassyarduino | 0:e3fb1267e3c3 | 109 | // or more than four segments |
cassyarduino | 0:e3fb1267e3c3 | 110 | return 0; |
cassyarduino | 0:e3fb1267e3c3 | 111 | } |
cassyarduino | 0:e3fb1267e3c3 | 112 | else |
cassyarduino | 0:e3fb1267e3c3 | 113 | { |
cassyarduino | 0:e3fb1267e3c3 | 114 | aResult[segment] = (uint8_t)segmentValue; |
cassyarduino | 0:e3fb1267e3c3 | 115 | return 1; |
cassyarduino | 0:e3fb1267e3c3 | 116 | } |
cassyarduino | 0:e3fb1267e3c3 | 117 | } |
cassyarduino | 0:e3fb1267e3c3 | 118 | else |
cassyarduino | 0:e3fb1267e3c3 | 119 | { |
cassyarduino | 0:e3fb1267e3c3 | 120 | return 0; |
cassyarduino | 0:e3fb1267e3c3 | 121 | } |
cassyarduino | 0:e3fb1267e3c3 | 122 | } |
cassyarduino | 0:e3fb1267e3c3 | 123 | |
cassyarduino | 0:e3fb1267e3c3 | 124 | int DNSClient::getHostByName(const char* aHostname, IPAddress& aResult) |
cassyarduino | 0:e3fb1267e3c3 | 125 | { |
cassyarduino | 0:e3fb1267e3c3 | 126 | int ret =0; |
cassyarduino | 0:e3fb1267e3c3 | 127 | |
cassyarduino | 0:e3fb1267e3c3 | 128 | // See if it's a numeric IP address |
cassyarduino | 0:e3fb1267e3c3 | 129 | if (inet_aton(aHostname, aResult)) |
cassyarduino | 0:e3fb1267e3c3 | 130 | { |
cassyarduino | 0:e3fb1267e3c3 | 131 | // It is, our work here is done |
cassyarduino | 0:e3fb1267e3c3 | 132 | return 1; |
cassyarduino | 0:e3fb1267e3c3 | 133 | } |
cassyarduino | 0:e3fb1267e3c3 | 134 | |
cassyarduino | 0:e3fb1267e3c3 | 135 | // Check we've got a valid DNS server to use |
cassyarduino | 0:e3fb1267e3c3 | 136 | if (iDNSServer == INADDR_NONE) |
cassyarduino | 0:e3fb1267e3c3 | 137 | { |
cassyarduino | 0:e3fb1267e3c3 | 138 | return INVALID_SERVER; |
cassyarduino | 0:e3fb1267e3c3 | 139 | } |
cassyarduino | 0:e3fb1267e3c3 | 140 | |
cassyarduino | 0:e3fb1267e3c3 | 141 | // Find a socket to use |
cassyarduino | 0:e3fb1267e3c3 | 142 | if (iUdp.begin(1024+(millis() & 0xF)) == 1) |
cassyarduino | 0:e3fb1267e3c3 | 143 | { |
cassyarduino | 0:e3fb1267e3c3 | 144 | // Try up to three times |
cassyarduino | 0:e3fb1267e3c3 | 145 | int retries = 0; |
cassyarduino | 0:e3fb1267e3c3 | 146 | // while ((retries < 3) && (ret <= 0)) |
cassyarduino | 0:e3fb1267e3c3 | 147 | { |
cassyarduino | 0:e3fb1267e3c3 | 148 | // Send DNS request |
cassyarduino | 0:e3fb1267e3c3 | 149 | ret = iUdp.beginPacket(iDNSServer, DNS_PORT); |
cassyarduino | 0:e3fb1267e3c3 | 150 | if (ret != 0) |
cassyarduino | 0:e3fb1267e3c3 | 151 | { |
cassyarduino | 0:e3fb1267e3c3 | 152 | // Now output the request data |
cassyarduino | 0:e3fb1267e3c3 | 153 | ret = BuildRequest(aHostname); |
cassyarduino | 0:e3fb1267e3c3 | 154 | if (ret != 0) |
cassyarduino | 0:e3fb1267e3c3 | 155 | { |
cassyarduino | 0:e3fb1267e3c3 | 156 | // And finally send the request |
cassyarduino | 0:e3fb1267e3c3 | 157 | ret = iUdp.endPacket(); |
cassyarduino | 0:e3fb1267e3c3 | 158 | if (ret != 0) |
cassyarduino | 0:e3fb1267e3c3 | 159 | { |
cassyarduino | 0:e3fb1267e3c3 | 160 | // Now wait for a response |
cassyarduino | 0:e3fb1267e3c3 | 161 | int wait_retries = 0; |
cassyarduino | 0:e3fb1267e3c3 | 162 | ret = TIMED_OUT; |
cassyarduino | 0:e3fb1267e3c3 | 163 | while ((wait_retries < 3) && (ret == TIMED_OUT)) |
cassyarduino | 0:e3fb1267e3c3 | 164 | { |
cassyarduino | 0:e3fb1267e3c3 | 165 | ret = ProcessResponse(5000, aResult); |
cassyarduino | 0:e3fb1267e3c3 | 166 | wait_retries++; |
cassyarduino | 0:e3fb1267e3c3 | 167 | } |
cassyarduino | 0:e3fb1267e3c3 | 168 | } |
cassyarduino | 0:e3fb1267e3c3 | 169 | } |
cassyarduino | 0:e3fb1267e3c3 | 170 | } |
cassyarduino | 0:e3fb1267e3c3 | 171 | retries++; |
cassyarduino | 0:e3fb1267e3c3 | 172 | } |
cassyarduino | 0:e3fb1267e3c3 | 173 | |
cassyarduino | 0:e3fb1267e3c3 | 174 | // We're done with the socket now |
cassyarduino | 0:e3fb1267e3c3 | 175 | iUdp.stop(); |
cassyarduino | 0:e3fb1267e3c3 | 176 | } |
cassyarduino | 0:e3fb1267e3c3 | 177 | |
cassyarduino | 0:e3fb1267e3c3 | 178 | return ret; |
cassyarduino | 0:e3fb1267e3c3 | 179 | } |
cassyarduino | 0:e3fb1267e3c3 | 180 | |
cassyarduino | 0:e3fb1267e3c3 | 181 | uint16_t DNSClient::BuildRequest(const char* aName) |
cassyarduino | 0:e3fb1267e3c3 | 182 | { |
cassyarduino | 0:e3fb1267e3c3 | 183 | // Build header |
cassyarduino | 0:e3fb1267e3c3 | 184 | // 1 1 1 1 1 1 |
cassyarduino | 0:e3fb1267e3c3 | 185 | // 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 |
cassyarduino | 0:e3fb1267e3c3 | 186 | // +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ |
cassyarduino | 0:e3fb1267e3c3 | 187 | // | ID | |
cassyarduino | 0:e3fb1267e3c3 | 188 | // +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ |
cassyarduino | 0:e3fb1267e3c3 | 189 | // |QR| Opcode |AA|TC|RD|RA| Z | RCODE | |
cassyarduino | 0:e3fb1267e3c3 | 190 | // +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ |
cassyarduino | 0:e3fb1267e3c3 | 191 | // | QDCOUNT | |
cassyarduino | 0:e3fb1267e3c3 | 192 | // +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ |
cassyarduino | 0:e3fb1267e3c3 | 193 | // | ANCOUNT | |
cassyarduino | 0:e3fb1267e3c3 | 194 | // +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ |
cassyarduino | 0:e3fb1267e3c3 | 195 | // | NSCOUNT | |
cassyarduino | 0:e3fb1267e3c3 | 196 | // +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ |
cassyarduino | 0:e3fb1267e3c3 | 197 | // | ARCOUNT | |
cassyarduino | 0:e3fb1267e3c3 | 198 | // +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ |
cassyarduino | 0:e3fb1267e3c3 | 199 | // As we only support one request at a time at present, we can simplify |
cassyarduino | 0:e3fb1267e3c3 | 200 | // some of this header |
cassyarduino | 0:e3fb1267e3c3 | 201 | iRequestId = millis(); // generate a random ID |
cassyarduino | 0:e3fb1267e3c3 | 202 | uint16_t twoByteBuffer; |
cassyarduino | 0:e3fb1267e3c3 | 203 | |
cassyarduino | 0:e3fb1267e3c3 | 204 | // FIXME We should also check that there's enough space available to write to, rather |
cassyarduino | 0:e3fb1267e3c3 | 205 | // FIXME than assume there's enough space (as the code does at present) |
cassyarduino | 0:e3fb1267e3c3 | 206 | iUdp.write((uint8_t*)&iRequestId, sizeof(iRequestId)); |
cassyarduino | 0:e3fb1267e3c3 | 207 | |
cassyarduino | 0:e3fb1267e3c3 | 208 | twoByteBuffer = htons(QUERY_FLAG | OPCODE_STANDARD_QUERY | RECURSION_DESIRED_FLAG); |
cassyarduino | 0:e3fb1267e3c3 | 209 | iUdp.write((uint8_t*)&twoByteBuffer, sizeof(twoByteBuffer)); |
cassyarduino | 0:e3fb1267e3c3 | 210 | |
cassyarduino | 0:e3fb1267e3c3 | 211 | twoByteBuffer = htons(1); // One question record |
cassyarduino | 0:e3fb1267e3c3 | 212 | iUdp.write((uint8_t*)&twoByteBuffer, sizeof(twoByteBuffer)); |
cassyarduino | 0:e3fb1267e3c3 | 213 | |
cassyarduino | 0:e3fb1267e3c3 | 214 | twoByteBuffer = 0; // Zero answer records |
cassyarduino | 0:e3fb1267e3c3 | 215 | iUdp.write((uint8_t*)&twoByteBuffer, sizeof(twoByteBuffer)); |
cassyarduino | 0:e3fb1267e3c3 | 216 | |
cassyarduino | 0:e3fb1267e3c3 | 217 | iUdp.write((uint8_t*)&twoByteBuffer, sizeof(twoByteBuffer)); |
cassyarduino | 0:e3fb1267e3c3 | 218 | // and zero additional records |
cassyarduino | 0:e3fb1267e3c3 | 219 | iUdp.write((uint8_t*)&twoByteBuffer, sizeof(twoByteBuffer)); |
cassyarduino | 0:e3fb1267e3c3 | 220 | |
cassyarduino | 0:e3fb1267e3c3 | 221 | // Build question |
cassyarduino | 0:e3fb1267e3c3 | 222 | const char* start =aName; |
cassyarduino | 0:e3fb1267e3c3 | 223 | const char* end =start; |
cassyarduino | 0:e3fb1267e3c3 | 224 | uint8_t len; |
cassyarduino | 0:e3fb1267e3c3 | 225 | // Run through the name being requested |
cassyarduino | 0:e3fb1267e3c3 | 226 | while (*end) |
cassyarduino | 0:e3fb1267e3c3 | 227 | { |
cassyarduino | 0:e3fb1267e3c3 | 228 | // Find out how long this section of the name is |
cassyarduino | 0:e3fb1267e3c3 | 229 | end = start; |
cassyarduino | 0:e3fb1267e3c3 | 230 | while (*end && (*end != '.') ) |
cassyarduino | 0:e3fb1267e3c3 | 231 | { |
cassyarduino | 0:e3fb1267e3c3 | 232 | end++; |
cassyarduino | 0:e3fb1267e3c3 | 233 | } |
cassyarduino | 0:e3fb1267e3c3 | 234 | |
cassyarduino | 0:e3fb1267e3c3 | 235 | if (end-start > 0) |
cassyarduino | 0:e3fb1267e3c3 | 236 | { |
cassyarduino | 0:e3fb1267e3c3 | 237 | // Write out the size of this section |
cassyarduino | 0:e3fb1267e3c3 | 238 | len = end-start; |
cassyarduino | 0:e3fb1267e3c3 | 239 | iUdp.write(&len, sizeof(len)); |
cassyarduino | 0:e3fb1267e3c3 | 240 | // And then write out the section |
cassyarduino | 0:e3fb1267e3c3 | 241 | iUdp.write((uint8_t*)start, end-start); |
cassyarduino | 0:e3fb1267e3c3 | 242 | } |
cassyarduino | 0:e3fb1267e3c3 | 243 | start = end+1; |
cassyarduino | 0:e3fb1267e3c3 | 244 | } |
cassyarduino | 0:e3fb1267e3c3 | 245 | |
cassyarduino | 0:e3fb1267e3c3 | 246 | // We've got to the end of the question name, so |
cassyarduino | 0:e3fb1267e3c3 | 247 | // terminate it with a zero-length section |
cassyarduino | 0:e3fb1267e3c3 | 248 | len = 0; |
cassyarduino | 0:e3fb1267e3c3 | 249 | iUdp.write(&len, sizeof(len)); |
cassyarduino | 0:e3fb1267e3c3 | 250 | // Finally the type and class of question |
cassyarduino | 0:e3fb1267e3c3 | 251 | twoByteBuffer = htons(TYPE_A); |
cassyarduino | 0:e3fb1267e3c3 | 252 | iUdp.write((uint8_t*)&twoByteBuffer, sizeof(twoByteBuffer)); |
cassyarduino | 0:e3fb1267e3c3 | 253 | |
cassyarduino | 0:e3fb1267e3c3 | 254 | twoByteBuffer = htons(CLASS_IN); // Internet class of question |
cassyarduino | 0:e3fb1267e3c3 | 255 | iUdp.write((uint8_t*)&twoByteBuffer, sizeof(twoByteBuffer)); |
cassyarduino | 0:e3fb1267e3c3 | 256 | // Success! Everything buffered okay |
cassyarduino | 0:e3fb1267e3c3 | 257 | return 1; |
cassyarduino | 0:e3fb1267e3c3 | 258 | } |
cassyarduino | 0:e3fb1267e3c3 | 259 | |
cassyarduino | 0:e3fb1267e3c3 | 260 | |
cassyarduino | 0:e3fb1267e3c3 | 261 | uint16_t DNSClient::ProcessResponse(uint16_t aTimeout, IPAddress& aAddress) |
cassyarduino | 0:e3fb1267e3c3 | 262 | { |
cassyarduino | 0:e3fb1267e3c3 | 263 | uint32_t startTime = millis(); |
cassyarduino | 0:e3fb1267e3c3 | 264 | |
cassyarduino | 0:e3fb1267e3c3 | 265 | // Wait for a response packet |
cassyarduino | 0:e3fb1267e3c3 | 266 | while(iUdp.parsePacket() <= 0) |
cassyarduino | 0:e3fb1267e3c3 | 267 | { |
cassyarduino | 0:e3fb1267e3c3 | 268 | if((millis() - startTime) > aTimeout) |
cassyarduino | 0:e3fb1267e3c3 | 269 | return TIMED_OUT; |
cassyarduino | 0:e3fb1267e3c3 | 270 | delay(50); |
cassyarduino | 0:e3fb1267e3c3 | 271 | } |
cassyarduino | 0:e3fb1267e3c3 | 272 | |
cassyarduino | 0:e3fb1267e3c3 | 273 | // We've had a reply! |
cassyarduino | 0:e3fb1267e3c3 | 274 | // Read the UDP header |
cassyarduino | 0:e3fb1267e3c3 | 275 | uint8_t header[DNS_HEADER_SIZE]; // Enough space to reuse for the DNS header |
cassyarduino | 0:e3fb1267e3c3 | 276 | // Check that it's a response from the right server and the right port |
cassyarduino | 0:e3fb1267e3c3 | 277 | if ( (iDNSServer != iUdp.remoteIP()) || |
cassyarduino | 0:e3fb1267e3c3 | 278 | (iUdp.remotePort() != DNS_PORT) ) |
cassyarduino | 0:e3fb1267e3c3 | 279 | { |
cassyarduino | 0:e3fb1267e3c3 | 280 | // It's not from who we expected |
cassyarduino | 0:e3fb1267e3c3 | 281 | return INVALID_SERVER; |
cassyarduino | 0:e3fb1267e3c3 | 282 | } |
cassyarduino | 0:e3fb1267e3c3 | 283 | |
cassyarduino | 0:e3fb1267e3c3 | 284 | // Read through the rest of the response |
cassyarduino | 0:e3fb1267e3c3 | 285 | if (iUdp.available() < DNS_HEADER_SIZE) |
cassyarduino | 0:e3fb1267e3c3 | 286 | { |
cassyarduino | 0:e3fb1267e3c3 | 287 | return TRUNCATED; |
cassyarduino | 0:e3fb1267e3c3 | 288 | } |
cassyarduino | 0:e3fb1267e3c3 | 289 | iUdp.read((char*)header, DNS_HEADER_SIZE); |
cassyarduino | 0:e3fb1267e3c3 | 290 | |
cassyarduino | 0:e3fb1267e3c3 | 291 | uint16_t header_flags = htons(*((uint16_t*)&header[2])); |
cassyarduino | 0:e3fb1267e3c3 | 292 | // Check that it's a response to this request |
cassyarduino | 0:e3fb1267e3c3 | 293 | if ( ( iRequestId != (*((uint16_t*)&header[0])) ) || |
cassyarduino | 0:e3fb1267e3c3 | 294 | ((header_flags & QUERY_RESPONSE_MASK) != (uint16_t)RESPONSE_FLAG) ) |
cassyarduino | 0:e3fb1267e3c3 | 295 | { |
cassyarduino | 0:e3fb1267e3c3 | 296 | // Mark the entire packet as read |
cassyarduino | 0:e3fb1267e3c3 | 297 | iUdp.flush(); |
cassyarduino | 0:e3fb1267e3c3 | 298 | return INVALID_RESPONSE; |
cassyarduino | 0:e3fb1267e3c3 | 299 | } |
cassyarduino | 0:e3fb1267e3c3 | 300 | // Check for any errors in the response (or in our request) |
cassyarduino | 0:e3fb1267e3c3 | 301 | // although we don't do anything to get round these |
cassyarduino | 0:e3fb1267e3c3 | 302 | if ( (header_flags & TRUNCATION_FLAG) || (header_flags & RESP_MASK) ) |
cassyarduino | 0:e3fb1267e3c3 | 303 | { |
cassyarduino | 0:e3fb1267e3c3 | 304 | // Mark the entire packet as read |
cassyarduino | 0:e3fb1267e3c3 | 305 | iUdp.flush(); |
cassyarduino | 0:e3fb1267e3c3 | 306 | return -5; //INVALID_RESPONSE; |
cassyarduino | 0:e3fb1267e3c3 | 307 | } |
cassyarduino | 0:e3fb1267e3c3 | 308 | |
cassyarduino | 0:e3fb1267e3c3 | 309 | // And make sure we've got (at least) one answer |
cassyarduino | 0:e3fb1267e3c3 | 310 | uint16_t answerCount = htons(*((uint16_t*)&header[6])); |
cassyarduino | 0:e3fb1267e3c3 | 311 | if (answerCount == 0 ) |
cassyarduino | 0:e3fb1267e3c3 | 312 | { |
cassyarduino | 0:e3fb1267e3c3 | 313 | // Mark the entire packet as read |
cassyarduino | 0:e3fb1267e3c3 | 314 | iUdp.flush(); |
cassyarduino | 0:e3fb1267e3c3 | 315 | return -6; //INVALID_RESPONSE; |
cassyarduino | 0:e3fb1267e3c3 | 316 | } |
cassyarduino | 0:e3fb1267e3c3 | 317 | |
cassyarduino | 0:e3fb1267e3c3 | 318 | // Skip over any questions |
cassyarduino | 0:e3fb1267e3c3 | 319 | for (uint16_t i =0; i < htons(*((uint16_t*)&header[4])); i++) |
cassyarduino | 0:e3fb1267e3c3 | 320 | { |
cassyarduino | 0:e3fb1267e3c3 | 321 | // Skip over the name |
cassyarduino | 0:e3fb1267e3c3 | 322 | uint8_t len; |
cassyarduino | 0:e3fb1267e3c3 | 323 | do |
cassyarduino | 0:e3fb1267e3c3 | 324 | { |
cassyarduino | 0:e3fb1267e3c3 | 325 | iUdp.read((char*)&len, sizeof(len)); |
cassyarduino | 0:e3fb1267e3c3 | 326 | if (len > 0) |
cassyarduino | 0:e3fb1267e3c3 | 327 | { |
cassyarduino | 0:e3fb1267e3c3 | 328 | // Don't need to actually read the data out for the string, just |
cassyarduino | 0:e3fb1267e3c3 | 329 | // advance ptr to beyond it |
cassyarduino | 0:e3fb1267e3c3 | 330 | while(len--) |
cassyarduino | 0:e3fb1267e3c3 | 331 | { |
cassyarduino | 0:e3fb1267e3c3 | 332 | iUdp.read(); // we don't care about the returned byte |
cassyarduino | 0:e3fb1267e3c3 | 333 | } |
cassyarduino | 0:e3fb1267e3c3 | 334 | } |
cassyarduino | 0:e3fb1267e3c3 | 335 | } while (len != 0); |
cassyarduino | 0:e3fb1267e3c3 | 336 | |
cassyarduino | 0:e3fb1267e3c3 | 337 | // Now jump over the type and class |
cassyarduino | 0:e3fb1267e3c3 | 338 | for (int i =0; i < 4; i++) |
cassyarduino | 0:e3fb1267e3c3 | 339 | { |
cassyarduino | 0:e3fb1267e3c3 | 340 | iUdp.read(); // we don't care about the returned byte |
cassyarduino | 0:e3fb1267e3c3 | 341 | } |
cassyarduino | 0:e3fb1267e3c3 | 342 | } |
cassyarduino | 0:e3fb1267e3c3 | 343 | |
cassyarduino | 0:e3fb1267e3c3 | 344 | // Now we're up to the bit we're interested in, the answer |
cassyarduino | 0:e3fb1267e3c3 | 345 | // There might be more than one answer (although we'll just use the first |
cassyarduino | 0:e3fb1267e3c3 | 346 | // type A answer) and some authority and additional resource records but |
cassyarduino | 0:e3fb1267e3c3 | 347 | // we're going to ignore all of them. |
cassyarduino | 0:e3fb1267e3c3 | 348 | |
cassyarduino | 0:e3fb1267e3c3 | 349 | for (uint16_t i =0; i < answerCount; i++) |
cassyarduino | 0:e3fb1267e3c3 | 350 | { |
cassyarduino | 0:e3fb1267e3c3 | 351 | // Skip the name |
cassyarduino | 0:e3fb1267e3c3 | 352 | uint8_t len; |
cassyarduino | 0:e3fb1267e3c3 | 353 | do |
cassyarduino | 0:e3fb1267e3c3 | 354 | { |
cassyarduino | 0:e3fb1267e3c3 | 355 | iUdp.read((char*)&len, sizeof(len)); |
cassyarduino | 0:e3fb1267e3c3 | 356 | if ((len & LABEL_COMPRESSION_MASK) == 0) |
cassyarduino | 0:e3fb1267e3c3 | 357 | { |
cassyarduino | 0:e3fb1267e3c3 | 358 | // It's just a normal label |
cassyarduino | 0:e3fb1267e3c3 | 359 | if (len > 0) |
cassyarduino | 0:e3fb1267e3c3 | 360 | { |
cassyarduino | 0:e3fb1267e3c3 | 361 | // And it's got a length |
cassyarduino | 0:e3fb1267e3c3 | 362 | // Don't need to actually read the data out for the string, |
cassyarduino | 0:e3fb1267e3c3 | 363 | // just advance ptr to beyond it |
cassyarduino | 0:e3fb1267e3c3 | 364 | while(len--) |
cassyarduino | 0:e3fb1267e3c3 | 365 | { |
cassyarduino | 0:e3fb1267e3c3 | 366 | iUdp.read(); // we don't care about the returned byte |
cassyarduino | 0:e3fb1267e3c3 | 367 | } |
cassyarduino | 0:e3fb1267e3c3 | 368 | } |
cassyarduino | 0:e3fb1267e3c3 | 369 | } |
cassyarduino | 0:e3fb1267e3c3 | 370 | else |
cassyarduino | 0:e3fb1267e3c3 | 371 | { |
cassyarduino | 0:e3fb1267e3c3 | 372 | // This is a pointer to a somewhere else in the message for the |
cassyarduino | 0:e3fb1267e3c3 | 373 | // rest of the name. We don't care about the name, and RFC1035 |
cassyarduino | 0:e3fb1267e3c3 | 374 | // says that a name is either a sequence of labels ended with a |
cassyarduino | 0:e3fb1267e3c3 | 375 | // 0 length octet or a pointer or a sequence of labels ending in |
cassyarduino | 0:e3fb1267e3c3 | 376 | // a pointer. Either way, when we get here we're at the end of |
cassyarduino | 0:e3fb1267e3c3 | 377 | // the name |
cassyarduino | 0:e3fb1267e3c3 | 378 | // Skip over the pointer |
cassyarduino | 0:e3fb1267e3c3 | 379 | iUdp.read(); // we don't care about the returned byte |
cassyarduino | 0:e3fb1267e3c3 | 380 | // And set len so that we drop out of the name loop |
cassyarduino | 0:e3fb1267e3c3 | 381 | len = 0; |
cassyarduino | 0:e3fb1267e3c3 | 382 | } |
cassyarduino | 0:e3fb1267e3c3 | 383 | } while (len != 0); |
cassyarduino | 0:e3fb1267e3c3 | 384 | |
cassyarduino | 0:e3fb1267e3c3 | 385 | // Check the type and class |
cassyarduino | 0:e3fb1267e3c3 | 386 | uint16_t answerType; |
cassyarduino | 0:e3fb1267e3c3 | 387 | uint16_t answerClass; |
cassyarduino | 0:e3fb1267e3c3 | 388 | iUdp.read((char*)&answerType, sizeof(answerType)); |
cassyarduino | 0:e3fb1267e3c3 | 389 | iUdp.read((char*)&answerClass, sizeof(answerClass)); |
cassyarduino | 0:e3fb1267e3c3 | 390 | |
cassyarduino | 0:e3fb1267e3c3 | 391 | // Ignore the Time-To-Live as we don't do any caching |
cassyarduino | 0:e3fb1267e3c3 | 392 | for (int i =0; i < TTL_SIZE; i++) |
cassyarduino | 0:e3fb1267e3c3 | 393 | { |
cassyarduino | 0:e3fb1267e3c3 | 394 | iUdp.read(); // we don't care about the returned byte |
cassyarduino | 0:e3fb1267e3c3 | 395 | } |
cassyarduino | 0:e3fb1267e3c3 | 396 | |
cassyarduino | 0:e3fb1267e3c3 | 397 | // And read out the length of this answer |
cassyarduino | 0:e3fb1267e3c3 | 398 | // Don't need header_flags anymore, so we can reuse it here |
cassyarduino | 0:e3fb1267e3c3 | 399 | iUdp.read((char*)&header_flags, sizeof(header_flags)); |
cassyarduino | 0:e3fb1267e3c3 | 400 | |
cassyarduino | 0:e3fb1267e3c3 | 401 | if ( (htons(answerType) == TYPE_A) && (htons(answerClass) == CLASS_IN) ) |
cassyarduino | 0:e3fb1267e3c3 | 402 | { |
cassyarduino | 0:e3fb1267e3c3 | 403 | if (htons(header_flags) != 4) |
cassyarduino | 0:e3fb1267e3c3 | 404 | { |
cassyarduino | 0:e3fb1267e3c3 | 405 | // It's a weird size |
cassyarduino | 0:e3fb1267e3c3 | 406 | // Mark the entire packet as read |
cassyarduino | 0:e3fb1267e3c3 | 407 | iUdp.flush(); |
cassyarduino | 0:e3fb1267e3c3 | 408 | return -9;//INVALID_RESPONSE; |
cassyarduino | 0:e3fb1267e3c3 | 409 | } |
cassyarduino | 0:e3fb1267e3c3 | 410 | iUdp.read((char*)aAddress.raw_address(), 4); |
cassyarduino | 0:e3fb1267e3c3 | 411 | return SUCCESS; |
cassyarduino | 0:e3fb1267e3c3 | 412 | } |
cassyarduino | 0:e3fb1267e3c3 | 413 | else |
cassyarduino | 0:e3fb1267e3c3 | 414 | { |
cassyarduino | 0:e3fb1267e3c3 | 415 | // This isn't an answer type we're after, move onto the next one |
cassyarduino | 0:e3fb1267e3c3 | 416 | for (uint16_t i =0; i < htons(header_flags); i++) |
cassyarduino | 0:e3fb1267e3c3 | 417 | { |
cassyarduino | 0:e3fb1267e3c3 | 418 | iUdp.read(); // we don't care about the returned byte |
cassyarduino | 0:e3fb1267e3c3 | 419 | } |
cassyarduino | 0:e3fb1267e3c3 | 420 | } |
cassyarduino | 0:e3fb1267e3c3 | 421 | } |
cassyarduino | 0:e3fb1267e3c3 | 422 | |
cassyarduino | 0:e3fb1267e3c3 | 423 | // Mark the entire packet as read |
cassyarduino | 0:e3fb1267e3c3 | 424 | iUdp.flush(); |
cassyarduino | 0:e3fb1267e3c3 | 425 | |
cassyarduino | 0:e3fb1267e3c3 | 426 | // If we get here then we haven't found an answer |
cassyarduino | 0:e3fb1267e3c3 | 427 | return -10;//INVALID_RESPONSE; |
cassyarduino | 0:e3fb1267e3c3 | 428 | } |
cassyarduino | 0:e3fb1267e3c3 | 429 |