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Dependencies:   LM75B M2XStreamClient jsonlite mbed-rtos mbed

Fork of m2x-seeed_ethernet_demo by Sean Newton

WIZnet_Library/WIZnetInterface/DNSClient/DNSClient.cpp@3:0fba8849a883, 2014-09-30 (annotated)

Committer:
SeanNewton
Date:
Tue Sep 30 00:32:20 2014 +0000
Revision:
3:0fba8849a883
Initial Release

Who changed what in which revision?

UserRevisionLine numberNew contents of line
SeanNewton 3:0fba8849a883 1 // DNSClient.cpp 2013/8/27
SeanNewton 3:0fba8849a883 2 #include "mbed.h"
SeanNewton 3:0fba8849a883 3 #include "mbed_debug.h"
SeanNewton 3:0fba8849a883 4 #include "DNSClient.h"
SeanNewton 3:0fba8849a883 5 #include "UDPSocket.h"
SeanNewton 3:0fba8849a883 6 #include "dnsname.h"
SeanNewton 3:0fba8849a883 7 #include "wiznet.h"
SeanNewton 3:0fba8849a883 8
SeanNewton 3:0fba8849a883 9 #define DBG_DNS 0
SeanNewton 3:0fba8849a883 10
SeanNewton 3:0fba8849a883 11 #if DBG_DNS
SeanNewton 3:0fba8849a883 12 #define DBG2(...) do{debug("[DNS]%p %d %s ", this,__LINE__,__PRETTY_FUNCTION__); debug(__VA_ARGS__); } while(0);
SeanNewton 3:0fba8849a883 13 #else
SeanNewton 3:0fba8849a883 14 #define DBG2(...) while(0);
SeanNewton 3:0fba8849a883 15 #endif
SeanNewton 3:0fba8849a883 16
SeanNewton 3:0fba8849a883 17 DNSClient::DNSClient(const char* hostname) : m_state(MYNETDNS_START), m_udp(NULL) {
SeanNewton 3:0fba8849a883 18 m_hostname = hostname;
SeanNewton 3:0fba8849a883 19 }
SeanNewton 3:0fba8849a883 20
SeanNewton 3:0fba8849a883 21 DNSClient::DNSClient(Endpoint* pHost) : m_state(MYNETDNS_START), m_udp(NULL) {
SeanNewton 3:0fba8849a883 22 }
SeanNewton 3:0fba8849a883 23
SeanNewton 3:0fba8849a883 24 DNSClient::~DNSClient() {
SeanNewton 3:0fba8849a883 25 if (m_udp) {
SeanNewton 3:0fba8849a883 26 delete m_udp;
SeanNewton 3:0fba8849a883 27 }
SeanNewton 3:0fba8849a883 28 }
SeanNewton 3:0fba8849a883 29
SeanNewton 3:0fba8849a883 30 void DNSClient::callback()
SeanNewton 3:0fba8849a883 31 {
SeanNewton 3:0fba8849a883 32 uint8_t buf[512];
SeanNewton 3:0fba8849a883 33 Endpoint host;
SeanNewton 3:0fba8849a883 34 int len = m_udp->receiveFrom(host, (char*)buf, sizeof(buf));
SeanNewton 3:0fba8849a883 35 if (len < 0) {
SeanNewton 3:0fba8849a883 36 return;
SeanNewton 3:0fba8849a883 37 }
SeanNewton 3:0fba8849a883 38 if (memcmp(buf+0, m_id, 2) != 0) { //verify
SeanNewton 3:0fba8849a883 39 return;
SeanNewton 3:0fba8849a883 40 }
SeanNewton 3:0fba8849a883 41 int rcode = response(buf, len);
SeanNewton 3:0fba8849a883 42 if (rcode == 0) {
SeanNewton 3:0fba8849a883 43 m_state = MYNETDNS_OK;
SeanNewton 3:0fba8849a883 44 } else {
SeanNewton 3:0fba8849a883 45 m_state = MYNETDNS_NOTFOUND;
SeanNewton 3:0fba8849a883 46 }
SeanNewton 3:0fba8849a883 47 }
SeanNewton 3:0fba8849a883 48
SeanNewton 3:0fba8849a883 49 int DNSClient::response(uint8_t buf[], int size) {
SeanNewton 3:0fba8849a883 50 int rcode = buf[3] & 0x0f;
SeanNewton 3:0fba8849a883 51 if (rcode != 0) {
SeanNewton 3:0fba8849a883 52 return rcode;
SeanNewton 3:0fba8849a883 53 }
SeanNewton 3:0fba8849a883 54 int qdcount = buf[4]<<8|buf[5];
SeanNewton 3:0fba8849a883 55 int ancount = buf[6]<<8|buf[7];
SeanNewton 3:0fba8849a883 56 int pos = 12;
SeanNewton 3:0fba8849a883 57 while(qdcount-- > 0) {
SeanNewton 3:0fba8849a883 58 dnsname qname(buf);
SeanNewton 3:0fba8849a883 59 pos = qname.decode(pos); // qname
SeanNewton 3:0fba8849a883 60 pos += 4; // qtype qclass
SeanNewton 3:0fba8849a883 61 }
SeanNewton 3:0fba8849a883 62 while(ancount-- > 0) {
SeanNewton 3:0fba8849a883 63 dnsname name(buf);
SeanNewton 3:0fba8849a883 64 pos = name.decode(pos); // name
SeanNewton 3:0fba8849a883 65 int type = buf[pos]<<8|buf[pos+1];
SeanNewton 3:0fba8849a883 66 pos += 8; // type class TTL
SeanNewton 3:0fba8849a883 67 int rdlength = buf[pos]<<8|buf[pos+1]; pos += 2;
SeanNewton 3:0fba8849a883 68 int rdata_pos = pos;
SeanNewton 3:0fba8849a883 69 pos += rdlength;
SeanNewton 3:0fba8849a883 70 if (type == 1) { // A record
SeanNewton 3:0fba8849a883 71 ip = (buf[rdata_pos]<<24) | (buf[rdata_pos+1]<<16) | (buf[rdata_pos+2]<<8) | buf[rdata_pos+3];
SeanNewton 3:0fba8849a883 72 }
SeanNewton 3:0fba8849a883 73 #if DBG_DNS
SeanNewton 3:0fba8849a883 74 printf("%s", name.str.c_str());
SeanNewton 3:0fba8849a883 75 if (type == 1) {
SeanNewton 3:0fba8849a883 76 printf(" A %d.%d.%d.%d\n",
SeanNewton 3:0fba8849a883 77 buf[rdata_pos],buf[rdata_pos+1],buf[rdata_pos+2],buf[rdata_pos+3]);
SeanNewton 3:0fba8849a883 78 } else if (type == 5) {
SeanNewton 3:0fba8849a883 79 dnsname rdname(buf);
SeanNewton 3:0fba8849a883 80 rdname.decode(rdata_pos);
SeanNewton 3:0fba8849a883 81 printf(" CNAME %s\n", rdname.str.c_str());
SeanNewton 3:0fba8849a883 82 } else {
SeanNewton 3:0fba8849a883 83 printf(" TYPE:%d", type);
SeanNewton 3:0fba8849a883 84 printfBytes(" RDATA:", &buf[rdata_pos], rdlength);
SeanNewton 3:0fba8849a883 85 }
SeanNewton 3:0fba8849a883 86 #endif
SeanNewton 3:0fba8849a883 87 }
SeanNewton 3:0fba8849a883 88 return rcode;
SeanNewton 3:0fba8849a883 89 }
SeanNewton 3:0fba8849a883 90
SeanNewton 3:0fba8849a883 91 int DNSClient::query(uint8_t buf[], int size, const char* hostname) {
SeanNewton 3:0fba8849a883 92 const uint8_t header[] = {
SeanNewton 3:0fba8849a883 93 0x00,0x00,0x01,0x00, // id=0x0000 QR=0 rd=1 opcode=0 rcode=0
SeanNewton 3:0fba8849a883 94 0x00,0x01,0x00,0x00, // qdcount=1 ancount=0
SeanNewton 3:0fba8849a883 95 0x00,0x00,0x00,0x00};// nscount=0 arcount=0
SeanNewton 3:0fba8849a883 96 const uint8_t tail[] = {0x00,0x01,0x00,0x01}; // qtype=A qclass=IN
SeanNewton 3:0fba8849a883 97 memcpy(buf, header, sizeof(header));
SeanNewton 3:0fba8849a883 98 int t = rand();
SeanNewton 3:0fba8849a883 99 m_id[0] = t>>8;
SeanNewton 3:0fba8849a883 100 m_id[1] = t;
SeanNewton 3:0fba8849a883 101 memcpy(buf, m_id, 2);
SeanNewton 3:0fba8849a883 102 dnsname qname(buf);
SeanNewton 3:0fba8849a883 103 int pos = qname.encode(sizeof(header), (char*)hostname);
SeanNewton 3:0fba8849a883 104 memcpy(buf+pos, tail, sizeof(tail));
SeanNewton 3:0fba8849a883 105 pos += sizeof(tail);
SeanNewton 3:0fba8849a883 106 return pos;
SeanNewton 3:0fba8849a883 107 }
SeanNewton 3:0fba8849a883 108
SeanNewton 3:0fba8849a883 109 void DNSClient::resolve(const char* hostname) {
SeanNewton 3:0fba8849a883 110 if (m_udp == NULL) {
SeanNewton 3:0fba8849a883 111 m_udp = new UDPSocket;
SeanNewton 3:0fba8849a883 112 }
SeanNewton 3:0fba8849a883 113 m_udp->init();
SeanNewton 3:0fba8849a883 114 m_udp->set_blocking(false);
SeanNewton 3:0fba8849a883 115 Endpoint server;
SeanNewton 3:0fba8849a883 116 server.set_address("8.8.8.8", 53); // DNS
SeanNewton 3:0fba8849a883 117 m_udp->bind(rand()&0x7fff);
SeanNewton 3:0fba8849a883 118 uint8_t buf[256];
SeanNewton 3:0fba8849a883 119 int size = query(buf, sizeof(buf), hostname);
SeanNewton 3:0fba8849a883 120 #if DBG_DNS
SeanNewton 3:0fba8849a883 121 printf("hostname:[%s]\n", hostname);
SeanNewton 3:0fba8849a883 122 printHex(buf, size);
SeanNewton 3:0fba8849a883 123 #endif
SeanNewton 3:0fba8849a883 124 m_udp->sendTo(server, (char*)buf, size);
SeanNewton 3:0fba8849a883 125 m_interval.reset();
SeanNewton 3:0fba8849a883 126 m_interval.start();
SeanNewton 3:0fba8849a883 127 }
SeanNewton 3:0fba8849a883 128
SeanNewton 3:0fba8849a883 129 void DNSClient::poll() {
SeanNewton 3:0fba8849a883 130 #if DBG_DNS
SeanNewton 3:0fba8849a883 131 printf("%p m_state: %d, m_udp: %p\n", this, m_state, m_udp);
SeanNewton 3:0fba8849a883 132 wait_ms(400);
SeanNewton 3:0fba8849a883 133 #endif
SeanNewton 3:0fba8849a883 134 switch(m_state) {
SeanNewton 3:0fba8849a883 135 case MYNETDNS_START:
SeanNewton 3:0fba8849a883 136 m_retry = 0;
SeanNewton 3:0fba8849a883 137 resolve(m_hostname);
SeanNewton 3:0fba8849a883 138 m_state = MYNETDNS_PROCESSING;
SeanNewton 3:0fba8849a883 139 break;
SeanNewton 3:0fba8849a883 140 case MYNETDNS_PROCESSING:
SeanNewton 3:0fba8849a883 141 break;
SeanNewton 3:0fba8849a883 142 case MYNETDNS_NOTFOUND:
SeanNewton 3:0fba8849a883 143 break;
SeanNewton 3:0fba8849a883 144 case MYNETDNS_ERROR:
SeanNewton 3:0fba8849a883 145 break;
SeanNewton 3:0fba8849a883 146 case MYNETDNS_OK:
SeanNewton 3:0fba8849a883 147 DBG2("m_retry=%d, m_interval=%d\n", m_retry, m_interval.read_ms());
SeanNewton 3:0fba8849a883 148 break;
SeanNewton 3:0fba8849a883 149 }
SeanNewton 3:0fba8849a883 150 if (m_interval.read_ms() > 1000) {
SeanNewton 3:0fba8849a883 151 m_interval.stop();
SeanNewton 3:0fba8849a883 152 DBG2("timeout m_retry=%d\n", m_retry);
SeanNewton 3:0fba8849a883 153 if (++m_retry >= 2) {
SeanNewton 3:0fba8849a883 154 m_state = MYNETDNS_ERROR;
SeanNewton 3:0fba8849a883 155 } else {
SeanNewton 3:0fba8849a883 156 resolve(m_hostname);
SeanNewton 3:0fba8849a883 157 m_state = MYNETDNS_PROCESSING;
SeanNewton 3:0fba8849a883 158 }
SeanNewton 3:0fba8849a883 159 }
SeanNewton 3:0fba8849a883 160 }
SeanNewton 3:0fba8849a883 161
SeanNewton 3:0fba8849a883 162 bool DNSClient::lookup(const char* hostname) {
SeanNewton 3:0fba8849a883 163 m_hostname = hostname;
SeanNewton 3:0fba8849a883 164 m_state = MYNETDNS_START;
SeanNewton 3:0fba8849a883 165 while(1) {
SeanNewton 3:0fba8849a883 166 poll();
SeanNewton 3:0fba8849a883 167 callback();
SeanNewton 3:0fba8849a883 168 if (m_state != MYNETDNS_PROCESSING) {
SeanNewton 3:0fba8849a883 169 break;
SeanNewton 3:0fba8849a883 170 }
SeanNewton 3:0fba8849a883 171 }
SeanNewton 3:0fba8849a883 172 return m_state == MYNETDNS_OK;
SeanNewton 3:0fba8849a883 173 }
SeanNewton 3:0fba8849a883 174