Paul Staron / W5500-Interface

Fork of original library, increased Tx buffer to 16kB

Dependents:   W5500-SNTPClient-example

DNSClient/DNSClient.cpp@0:e9275bdfa393, 2019-05-02 (annotated)

Committer:
star297
Date:
Thu May 02 20:47:25 2019 +0000
Revision:
0:e9275bdfa393
First commit

Who changed what in which revision?

UserRevisionLine numberNew contents of line
star297 0:e9275bdfa393 1 // DNSClient.cpp 2013/8/27
star297 0:e9275bdfa393 2 #include "mbed.h"
star297 0:e9275bdfa393 3 #include "mbed_debug.h"
star297 0:e9275bdfa393 4 #include "DNSClient.h"
star297 0:e9275bdfa393 5 #include "UDPSocket.h"
star297 0:e9275bdfa393 6 #include "dnsname.h"
star297 0:e9275bdfa393 7 #include "wiznet.h"
star297 0:e9275bdfa393 8
star297 0:e9275bdfa393 9 #define DBG_DNS 0
star297 0:e9275bdfa393 10
star297 0:e9275bdfa393 11 #if DBG_DNS
star297 0:e9275bdfa393 12 #define DBG2(...) do{debug("[DNS]%p %d %s ", this,__LINE__,__PRETTY_FUNCTION__); debug(__VA_ARGS__); } while(0);
star297 0:e9275bdfa393 13 #else
star297 0:e9275bdfa393 14 #define DBG2(...) while(0);
star297 0:e9275bdfa393 15 #endif
star297 0:e9275bdfa393 16
star297 0:e9275bdfa393 17 DNSClient::DNSClient(const char* hostname) : m_state(MYNETDNS_START), m_udp(NULL) {
star297 0:e9275bdfa393 18 m_hostname = hostname;
star297 0:e9275bdfa393 19 }
star297 0:e9275bdfa393 20
star297 0:e9275bdfa393 21 DNSClient::DNSClient(Endpoint* pHost) : m_state(MYNETDNS_START), m_udp(NULL) {
star297 0:e9275bdfa393 22 }
star297 0:e9275bdfa393 23
star297 0:e9275bdfa393 24 DNSClient::~DNSClient() {
star297 0:e9275bdfa393 25 if (m_udp) {
star297 0:e9275bdfa393 26 delete m_udp;
star297 0:e9275bdfa393 27 }
star297 0:e9275bdfa393 28 }
star297 0:e9275bdfa393 29
star297 0:e9275bdfa393 30 void DNSClient::callback()
star297 0:e9275bdfa393 31 {
star297 0:e9275bdfa393 32 uint8_t buf[512];
star297 0:e9275bdfa393 33 Endpoint host;
star297 0:e9275bdfa393 34 int len = m_udp->receiveFrom(host, (char*)buf, sizeof(buf));
star297 0:e9275bdfa393 35 if (len < 0) {
star297 0:e9275bdfa393 36 return;
star297 0:e9275bdfa393 37 }
star297 0:e9275bdfa393 38 if (memcmp(buf+0, m_id, 2) != 0) { //verify
star297 0:e9275bdfa393 39 return;
star297 0:e9275bdfa393 40 }
star297 0:e9275bdfa393 41 int rcode = response(buf, len);
star297 0:e9275bdfa393 42 if (rcode == 0) {
star297 0:e9275bdfa393 43 m_state = MYNETDNS_OK;
star297 0:e9275bdfa393 44 } else {
star297 0:e9275bdfa393 45 m_state = MYNETDNS_NOTFOUND;
star297 0:e9275bdfa393 46 }
star297 0:e9275bdfa393 47 }
star297 0:e9275bdfa393 48
star297 0:e9275bdfa393 49 int DNSClient::response(uint8_t buf[], int size) {
star297 0:e9275bdfa393 50 int rcode = buf[3] & 0x0f;
star297 0:e9275bdfa393 51 if (rcode != 0) {
star297 0:e9275bdfa393 52 return rcode;
star297 0:e9275bdfa393 53 }
star297 0:e9275bdfa393 54 int qdcount = buf[4]<<8|buf[5];
star297 0:e9275bdfa393 55 int ancount = buf[6]<<8|buf[7];
star297 0:e9275bdfa393 56 int pos = 12;
star297 0:e9275bdfa393 57 while(qdcount-- > 0) {
star297 0:e9275bdfa393 58 dnsname qname(buf);
star297 0:e9275bdfa393 59 pos = qname.decode(pos); // qname
star297 0:e9275bdfa393 60 pos += 4; // qtype qclass
star297 0:e9275bdfa393 61 }
star297 0:e9275bdfa393 62 while(ancount-- > 0) {
star297 0:e9275bdfa393 63 dnsname name(buf);
star297 0:e9275bdfa393 64 pos = name.decode(pos); // name
star297 0:e9275bdfa393 65 int type = buf[pos]<<8|buf[pos+1];
star297 0:e9275bdfa393 66 pos += 8; // type class TTL
star297 0:e9275bdfa393 67 int rdlength = buf[pos]<<8|buf[pos+1]; pos += 2;
star297 0:e9275bdfa393 68 int rdata_pos = pos;
star297 0:e9275bdfa393 69 pos += rdlength;
star297 0:e9275bdfa393 70 if (type == 1) { // A record
star297 0:e9275bdfa393 71 ip = (buf[rdata_pos]<<24) | (buf[rdata_pos+1]<<16) | (buf[rdata_pos+2]<<8) | buf[rdata_pos+3];
star297 0:e9275bdfa393 72 }
star297 0:e9275bdfa393 73 #if DBG_DNS
star297 0:e9275bdfa393 74 printf("%s", name.str.c_str());
star297 0:e9275bdfa393 75 if (type == 1) {
star297 0:e9275bdfa393 76 printf(" A %d.%d.%d.%d\n",
star297 0:e9275bdfa393 77 buf[rdata_pos],buf[rdata_pos+1],buf[rdata_pos+2],buf[rdata_pos+3]);
star297 0:e9275bdfa393 78 } else if (type == 5) {
star297 0:e9275bdfa393 79 dnsname rdname(buf);
star297 0:e9275bdfa393 80 rdname.decode(rdata_pos);
star297 0:e9275bdfa393 81 printf(" CNAME %s\n", rdname.str.c_str());
star297 0:e9275bdfa393 82 } else {
star297 0:e9275bdfa393 83 printf(" TYPE:%d", type);
star297 0:e9275bdfa393 84 printfBytes(" RDATA:", &buf[rdata_pos], rdlength);
star297 0:e9275bdfa393 85 }
star297 0:e9275bdfa393 86 #endif
star297 0:e9275bdfa393 87 }
star297 0:e9275bdfa393 88 return rcode;
star297 0:e9275bdfa393 89 }
star297 0:e9275bdfa393 90
star297 0:e9275bdfa393 91 int DNSClient::query(uint8_t buf[], int size, const char* hostname) {
star297 0:e9275bdfa393 92 const uint8_t header[] = {
star297 0:e9275bdfa393 93 0x00,0x00,0x01,0x00, // id=0x0000 QR=0 rd=1 opcode=0 rcode=0
star297 0:e9275bdfa393 94 0x00,0x01,0x00,0x00, // qdcount=1 ancount=0
star297 0:e9275bdfa393 95 0x00,0x00,0x00,0x00};// nscount=0 arcount=0
star297 0:e9275bdfa393 96 const uint8_t tail[] = {0x00,0x01,0x00,0x01}; // qtype=A qclass=IN
star297 0:e9275bdfa393 97 memcpy(buf, header, sizeof(header));
star297 0:e9275bdfa393 98 int t = rand();
star297 0:e9275bdfa393 99 m_id[0] = t>>8;
star297 0:e9275bdfa393 100 m_id[1] = t;
star297 0:e9275bdfa393 101 memcpy(buf, m_id, 2);
star297 0:e9275bdfa393 102 dnsname qname(buf);
star297 0:e9275bdfa393 103 int pos = qname.encode(sizeof(header), (char*)hostname);
star297 0:e9275bdfa393 104 memcpy(buf+pos, tail, sizeof(tail));
star297 0:e9275bdfa393 105 pos += sizeof(tail);
star297 0:e9275bdfa393 106 return pos;
star297 0:e9275bdfa393 107 }
star297 0:e9275bdfa393 108
star297 0:e9275bdfa393 109 void DNSClient::resolve(const char* hostname) {
star297 0:e9275bdfa393 110 if (m_udp == NULL) {
star297 0:e9275bdfa393 111 m_udp = new UDPSocket;
star297 0:e9275bdfa393 112 }
star297 0:e9275bdfa393 113 m_udp->init();
star297 0:e9275bdfa393 114 m_udp->set_blocking(false);
star297 0:e9275bdfa393 115 Endpoint server;
star297 0:e9275bdfa393 116 server.set_address("8.8.8.8", 53); // DNS
star297 0:e9275bdfa393 117 m_udp->bind(rand()&0x7fff);
star297 0:e9275bdfa393 118 uint8_t buf[256];
star297 0:e9275bdfa393 119 int size = query(buf, sizeof(buf), hostname);
star297 0:e9275bdfa393 120 #if DBG_DNS
star297 0:e9275bdfa393 121 printf("hostname:[%s]\n", hostname);
star297 0:e9275bdfa393 122 printHex(buf, size);
star297 0:e9275bdfa393 123 #endif
star297 0:e9275bdfa393 124 m_udp->sendTo(server, (char*)buf, size);
star297 0:e9275bdfa393 125 m_interval.reset();
star297 0:e9275bdfa393 126 m_interval.start();
star297 0:e9275bdfa393 127 }
star297 0:e9275bdfa393 128
star297 0:e9275bdfa393 129 void DNSClient::poll() {
star297 0:e9275bdfa393 130 #if DBG_DNS
star297 0:e9275bdfa393 131 printf("%p m_state: %d, m_udp: %p\n", this, m_state, m_udp);
star297 0:e9275bdfa393 132 wait_ms(400);
star297 0:e9275bdfa393 133 #endif
star297 0:e9275bdfa393 134 switch(m_state) {
star297 0:e9275bdfa393 135 case MYNETDNS_START:
star297 0:e9275bdfa393 136 m_retry = 0;
star297 0:e9275bdfa393 137 resolve(m_hostname);
star297 0:e9275bdfa393 138 m_state = MYNETDNS_PROCESSING;
star297 0:e9275bdfa393 139 break;
star297 0:e9275bdfa393 140 case MYNETDNS_PROCESSING:
star297 0:e9275bdfa393 141 break;
star297 0:e9275bdfa393 142 case MYNETDNS_NOTFOUND:
star297 0:e9275bdfa393 143 break;
star297 0:e9275bdfa393 144 case MYNETDNS_ERROR:
star297 0:e9275bdfa393 145 break;
star297 0:e9275bdfa393 146 case MYNETDNS_OK:
star297 0:e9275bdfa393 147 DBG2("m_retry=%d, m_interval=%d\n", m_retry, m_interval.read_ms());
star297 0:e9275bdfa393 148 break;
star297 0:e9275bdfa393 149 }
star297 0:e9275bdfa393 150 if (m_interval.read_ms() > 1000) {
star297 0:e9275bdfa393 151 m_interval.stop();
star297 0:e9275bdfa393 152 DBG2("timeout m_retry=%d\n", m_retry);
star297 0:e9275bdfa393 153 if (++m_retry >= 2) {
star297 0:e9275bdfa393 154 m_state = MYNETDNS_ERROR;
star297 0:e9275bdfa393 155 } else {
star297 0:e9275bdfa393 156 resolve(m_hostname);
star297 0:e9275bdfa393 157 m_state = MYNETDNS_PROCESSING;
star297 0:e9275bdfa393 158 }
star297 0:e9275bdfa393 159 }
star297 0:e9275bdfa393 160 }
star297 0:e9275bdfa393 161
star297 0:e9275bdfa393 162 bool DNSClient::lookup(const char* hostname) {
star297 0:e9275bdfa393 163 m_hostname = hostname;
star297 0:e9275bdfa393 164 m_state = MYNETDNS_START;
star297 0:e9275bdfa393 165 while(1) {
star297 0:e9275bdfa393 166 poll();
star297 0:e9275bdfa393 167 callback();
star297 0:e9275bdfa393 168 if (m_state != MYNETDNS_PROCESSING) {
star297 0:e9275bdfa393 169 break;
star297 0:e9275bdfa393 170 }
star297 0:e9275bdfa393 171 }
star297 0:e9275bdfa393 172 return m_state == MYNETDNS_OK;
star297 0:e9275bdfa393 173 }