Hill Kim / W5200Interface

MQTT client test with W5200 ethernet shield

Dependents:   IBMIoTClientEthernetExample_W5200

Fork of W5500Interface by W5500-Ethernet-Interface Makers

DNSClient/DNSClient.cpp@0:e11e8793c3ce, 2014-08-20 (annotated)

Committer:
Bongjun
Date:
Wed Aug 20 00:28:37 2014 +0000
Revision:
0:e11e8793c3ce
first release.

Who changed what in which revision?

UserRevisionLine numberNew contents of line
Bongjun 0:e11e8793c3ce 1 // DNSClient.cpp 2013/8/27
Bongjun 0:e11e8793c3ce 2 #include "mbed.h"
Bongjun 0:e11e8793c3ce 3 #include "mbed_debug.h"
Bongjun 0:e11e8793c3ce 4 #include "DNSClient.h"
Bongjun 0:e11e8793c3ce 5 #include "UDPSocket.h"
Bongjun 0:e11e8793c3ce 6 #include "dnsname.h"
Bongjun 0:e11e8793c3ce 7 #include "wiznet.h"
Bongjun 0:e11e8793c3ce 8
Bongjun 0:e11e8793c3ce 9 #define DBG_DNS 0
Bongjun 0:e11e8793c3ce 10
Bongjun 0:e11e8793c3ce 11 #if DBG_DNS
Bongjun 0:e11e8793c3ce 12 #define DBG2(...) do{debug("[DNS]%p %d %s ", this,__LINE__,__PRETTY_FUNCTION__); debug(__VA_ARGS__); } while(0);
Bongjun 0:e11e8793c3ce 13 #else
Bongjun 0:e11e8793c3ce 14 #define DBG2(...) while(0);
Bongjun 0:e11e8793c3ce 15 #endif
Bongjun 0:e11e8793c3ce 16
Bongjun 0:e11e8793c3ce 17 DNSClient::DNSClient(const char* hostname) : m_state(MYNETDNS_START), m_udp(NULL) {
Bongjun 0:e11e8793c3ce 18 m_hostname = hostname;
Bongjun 0:e11e8793c3ce 19 }
Bongjun 0:e11e8793c3ce 20
Bongjun 0:e11e8793c3ce 21 DNSClient::DNSClient(Endpoint* pHost) : m_state(MYNETDNS_START), m_udp(NULL) {
Bongjun 0:e11e8793c3ce 22 }
Bongjun 0:e11e8793c3ce 23
Bongjun 0:e11e8793c3ce 24 DNSClient::~DNSClient() {
Bongjun 0:e11e8793c3ce 25 if (m_udp) {
Bongjun 0:e11e8793c3ce 26 delete m_udp;
Bongjun 0:e11e8793c3ce 27 }
Bongjun 0:e11e8793c3ce 28 }
Bongjun 0:e11e8793c3ce 29
Bongjun 0:e11e8793c3ce 30 void DNSClient::callback()
Bongjun 0:e11e8793c3ce 31 {
Bongjun 0:e11e8793c3ce 32 uint8_t buf[512];
Bongjun 0:e11e8793c3ce 33 Endpoint host;
Bongjun 0:e11e8793c3ce 34 int len = m_udp->receiveFrom(host, (char*)buf, sizeof(buf));
Bongjun 0:e11e8793c3ce 35 if (len < 0) {
Bongjun 0:e11e8793c3ce 36 return;
Bongjun 0:e11e8793c3ce 37 }
Bongjun 0:e11e8793c3ce 38 if (memcmp(buf+0, m_id, 2) != 0) { //verify
Bongjun 0:e11e8793c3ce 39 return;
Bongjun 0:e11e8793c3ce 40 }
Bongjun 0:e11e8793c3ce 41 int rcode = response(buf, len);
Bongjun 0:e11e8793c3ce 42 if (rcode == 0) {
Bongjun 0:e11e8793c3ce 43 m_state = MYNETDNS_OK;
Bongjun 0:e11e8793c3ce 44 } else {
Bongjun 0:e11e8793c3ce 45 m_state = MYNETDNS_NOTFOUND;
Bongjun 0:e11e8793c3ce 46 }
Bongjun 0:e11e8793c3ce 47 }
Bongjun 0:e11e8793c3ce 48
Bongjun 0:e11e8793c3ce 49 int DNSClient::response(uint8_t buf[], int size) {
Bongjun 0:e11e8793c3ce 50 int rcode = buf[3] & 0x0f;
Bongjun 0:e11e8793c3ce 51 if (rcode != 0) {
Bongjun 0:e11e8793c3ce 52 return rcode;
Bongjun 0:e11e8793c3ce 53 }
Bongjun 0:e11e8793c3ce 54 int qdcount = buf[4]<<8|buf[5];
Bongjun 0:e11e8793c3ce 55 int ancount = buf[6]<<8|buf[7];
Bongjun 0:e11e8793c3ce 56 int pos = 12;
Bongjun 0:e11e8793c3ce 57 while(qdcount-- > 0) {
Bongjun 0:e11e8793c3ce 58 dnsname qname(buf);
Bongjun 0:e11e8793c3ce 59 pos = qname.decode(pos); // qname
Bongjun 0:e11e8793c3ce 60 pos += 4; // qtype qclass
Bongjun 0:e11e8793c3ce 61 }
Bongjun 0:e11e8793c3ce 62 while(ancount-- > 0) {
Bongjun 0:e11e8793c3ce 63 dnsname name(buf);
Bongjun 0:e11e8793c3ce 64 pos = name.decode(pos); // name
Bongjun 0:e11e8793c3ce 65 int type = buf[pos]<<8|buf[pos+1];
Bongjun 0:e11e8793c3ce 66 pos += 8; // type class TTL
Bongjun 0:e11e8793c3ce 67 int rdlength = buf[pos]<<8|buf[pos+1]; pos += 2;
Bongjun 0:e11e8793c3ce 68 int rdata_pos = pos;
Bongjun 0:e11e8793c3ce 69 pos += rdlength;
Bongjun 0:e11e8793c3ce 70 if (type == 1) { // A record
Bongjun 0:e11e8793c3ce 71 ip = (buf[rdata_pos]<<24) | (buf[rdata_pos+1]<<16) | (buf[rdata_pos+2]<<8) | buf[rdata_pos+3];
Bongjun 0:e11e8793c3ce 72 }
Bongjun 0:e11e8793c3ce 73 #if DBG_DNS
Bongjun 0:e11e8793c3ce 74 printf("%s", name.str.c_str());
Bongjun 0:e11e8793c3ce 75 if (type == 1) {
Bongjun 0:e11e8793c3ce 76 printf(" A %d.%d.%d.%d\n",
Bongjun 0:e11e8793c3ce 77 buf[rdata_pos],buf[rdata_pos+1],buf[rdata_pos+2],buf[rdata_pos+3]);
Bongjun 0:e11e8793c3ce 78 } else if (type == 5) {
Bongjun 0:e11e8793c3ce 79 dnsname rdname(buf);
Bongjun 0:e11e8793c3ce 80 rdname.decode(rdata_pos);
Bongjun 0:e11e8793c3ce 81 printf(" CNAME %s\n", rdname.str.c_str());
Bongjun 0:e11e8793c3ce 82 } else {
Bongjun 0:e11e8793c3ce 83 printf(" TYPE:%d", type);
Bongjun 0:e11e8793c3ce 84 printfBytes(" RDATA:", &buf[rdata_pos], rdlength);
Bongjun 0:e11e8793c3ce 85 }
Bongjun 0:e11e8793c3ce 86 #endif
Bongjun 0:e11e8793c3ce 87 }
Bongjun 0:e11e8793c3ce 88 return rcode;
Bongjun 0:e11e8793c3ce 89 }
Bongjun 0:e11e8793c3ce 90
Bongjun 0:e11e8793c3ce 91 int DNSClient::query(uint8_t buf[], int size, const char* hostname) {
Bongjun 0:e11e8793c3ce 92 const uint8_t header[] = {
Bongjun 0:e11e8793c3ce 93 0x00,0x00,0x01,0x00, // id=0x0000 QR=0 rd=1 opcode=0 rcode=0
Bongjun 0:e11e8793c3ce 94 0x00,0x01,0x00,0x00, // qdcount=1 ancount=0
Bongjun 0:e11e8793c3ce 95 0x00,0x00,0x00,0x00};// nscount=0 arcount=0
Bongjun 0:e11e8793c3ce 96 const uint8_t tail[] = {0x00,0x01,0x00,0x01}; // qtype=A qclass=IN
Bongjun 0:e11e8793c3ce 97 memcpy(buf, header, sizeof(header));
Bongjun 0:e11e8793c3ce 98 int t = rand();
Bongjun 0:e11e8793c3ce 99 m_id[0] = t>>8;
Bongjun 0:e11e8793c3ce 100 m_id[1] = t;
Bongjun 0:e11e8793c3ce 101 memcpy(buf, m_id, 2);
Bongjun 0:e11e8793c3ce 102 dnsname qname(buf);
Bongjun 0:e11e8793c3ce 103 int pos = qname.encode(sizeof(header), (char*)hostname);
Bongjun 0:e11e8793c3ce 104 memcpy(buf+pos, tail, sizeof(tail));
Bongjun 0:e11e8793c3ce 105 pos += sizeof(tail);
Bongjun 0:e11e8793c3ce 106 return pos;
Bongjun 0:e11e8793c3ce 107 }
Bongjun 0:e11e8793c3ce 108
Bongjun 0:e11e8793c3ce 109 void DNSClient::resolve(const char* hostname) {
Bongjun 0:e11e8793c3ce 110 if (m_udp == NULL) {
Bongjun 0:e11e8793c3ce 111 m_udp = new UDPSocket;
Bongjun 0:e11e8793c3ce 112 }
Bongjun 0:e11e8793c3ce 113 m_udp->init();
Bongjun 0:e11e8793c3ce 114 m_udp->set_blocking(false);
Bongjun 0:e11e8793c3ce 115 Endpoint server;
Bongjun 0:e11e8793c3ce 116 server.set_address("8.8.8.8", 53); // DNS
Bongjun 0:e11e8793c3ce 117 m_udp->bind(rand()&0x7fff);
Bongjun 0:e11e8793c3ce 118 uint8_t buf[256];
Bongjun 0:e11e8793c3ce 119 int size = query(buf, sizeof(buf), hostname);
Bongjun 0:e11e8793c3ce 120 #if DBG_DNS
Bongjun 0:e11e8793c3ce 121 printf("hostname:[%s]\n", hostname);
Bongjun 0:e11e8793c3ce 122 printHex(buf, size);
Bongjun 0:e11e8793c3ce 123 #endif
Bongjun 0:e11e8793c3ce 124 m_udp->sendTo(server, (char*)buf, size);
Bongjun 0:e11e8793c3ce 125 m_interval.reset();
Bongjun 0:e11e8793c3ce 126 m_interval.start();
Bongjun 0:e11e8793c3ce 127 }
Bongjun 0:e11e8793c3ce 128
Bongjun 0:e11e8793c3ce 129 void DNSClient::poll() {
Bongjun 0:e11e8793c3ce 130 #if DBG_DNS
Bongjun 0:e11e8793c3ce 131 printf("%p m_state: %d, m_udp: %p\n", this, m_state, m_udp);
Bongjun 0:e11e8793c3ce 132 wait_ms(400);
Bongjun 0:e11e8793c3ce 133 #endif
Bongjun 0:e11e8793c3ce 134 switch(m_state) {
Bongjun 0:e11e8793c3ce 135 case MYNETDNS_START:
Bongjun 0:e11e8793c3ce 136 m_retry = 0;
Bongjun 0:e11e8793c3ce 137 resolve(m_hostname);
Bongjun 0:e11e8793c3ce 138 m_state = MYNETDNS_PROCESSING;
Bongjun 0:e11e8793c3ce 139 break;
Bongjun 0:e11e8793c3ce 140 case MYNETDNS_PROCESSING:
Bongjun 0:e11e8793c3ce 141 break;
Bongjun 0:e11e8793c3ce 142 case MYNETDNS_NOTFOUND:
Bongjun 0:e11e8793c3ce 143 break;
Bongjun 0:e11e8793c3ce 144 case MYNETDNS_ERROR:
Bongjun 0:e11e8793c3ce 145 break;
Bongjun 0:e11e8793c3ce 146 case MYNETDNS_OK:
Bongjun 0:e11e8793c3ce 147 DBG2("m_retry=%d, m_interval=%d\n", m_retry, m_interval.read_ms());
Bongjun 0:e11e8793c3ce 148 break;
Bongjun 0:e11e8793c3ce 149 }
Bongjun 0:e11e8793c3ce 150 if (m_interval.read_ms() > 1000) {
Bongjun 0:e11e8793c3ce 151 m_interval.stop();
Bongjun 0:e11e8793c3ce 152 DBG2("timeout m_retry=%d\n", m_retry);
Bongjun 0:e11e8793c3ce 153 if (++m_retry >= 2) {
Bongjun 0:e11e8793c3ce 154 m_state = MYNETDNS_ERROR;
Bongjun 0:e11e8793c3ce 155 } else {
Bongjun 0:e11e8793c3ce 156 resolve(m_hostname);
Bongjun 0:e11e8793c3ce 157 m_state = MYNETDNS_PROCESSING;
Bongjun 0:e11e8793c3ce 158 }
Bongjun 0:e11e8793c3ce 159 }
Bongjun 0:e11e8793c3ce 160 }
Bongjun 0:e11e8793c3ce 161
Bongjun 0:e11e8793c3ce 162 bool DNSClient::lookup(const char* hostname) {
Bongjun 0:e11e8793c3ce 163 m_hostname = hostname;
Bongjun 0:e11e8793c3ce 164 m_state = MYNETDNS_START;
Bongjun 0:e11e8793c3ce 165 while(1) {
Bongjun 0:e11e8793c3ce 166 poll();
Bongjun 0:e11e8793c3ce 167 callback();
Bongjun 0:e11e8793c3ce 168 if (m_state != MYNETDNS_PROCESSING) {
Bongjun 0:e11e8793c3ce 169 break;
Bongjun 0:e11e8793c3ce 170 }
Bongjun 0:e11e8793c3ce 171 }
Bongjun 0:e11e8793c3ce 172 return m_state == MYNETDNS_OK;
Bongjun 0:e11e8793c3ce 173 }