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Dependents:   PwrCond_mbed5

Fork of W5500Interface_K22F by Andrew McCartney

DNSClient/DNSClient.cpp@15:14382459c8b7, 2017-06-15 (annotated)

Committer:
dgriffin65
Date:
Thu Jun 15 20:29:03 2017 +0000
Revision:
15:14382459c8b7
Converted to a single library

Who changed what in which revision?

UserRevisionLine numberNew contents of line
dgriffin65 15:14382459c8b7 1 // DNSClient.cpp 2013/8/27
dgriffin65 15:14382459c8b7 2 #include "mbed.h"
dgriffin65 15:14382459c8b7 3 #include "mbed_debug.h"
dgriffin65 15:14382459c8b7 4 #include "DNSClient.h"
dgriffin65 15:14382459c8b7 5 #include "UDPSocket.h"
dgriffin65 15:14382459c8b7 6 #include "dnsname.h"
dgriffin65 15:14382459c8b7 7 #include "wiznet.h"
dgriffin65 15:14382459c8b7 8
dgriffin65 15:14382459c8b7 9 #if DBG_DNS
dgriffin65 15:14382459c8b7 10 #define DBG2(...) do{debug("[DNS]%p %d %s ", this,__LINE__,__PRETTY_FUNCTION__); debug(__VA_ARGS__); } while(0);
dgriffin65 15:14382459c8b7 11 #else
dgriffin65 15:14382459c8b7 12 #define DBG2(...) while(0);
dgriffin65 15:14382459c8b7 13 #endif
dgriffin65 15:14382459c8b7 14
dgriffin65 15:14382459c8b7 15 static SocketAddress theDnsServer;
dgriffin65 15:14382459c8b7 16
dgriffin65 15:14382459c8b7 17 DNSClient::DNSClient() : m_state(MYNETDNS_START), m_udp(NULL) {
dgriffin65 15:14382459c8b7 18 m_ns = NULL;
dgriffin65 15:14382459c8b7 19
dgriffin65 15:14382459c8b7 20 //default to google
dgriffin65 15:14382459c8b7 21 theDnsServer.set_ip_address("8.8.8.8"); // DNS
dgriffin65 15:14382459c8b7 22 theDnsServer.set_port(53); // DNS
dgriffin65 15:14382459c8b7 23 }
dgriffin65 15:14382459c8b7 24
dgriffin65 15:14382459c8b7 25 DNSClient::DNSClient(NetworkStack *ns, const char* hostname) : m_state(MYNETDNS_START), m_udp(NULL) {
dgriffin65 15:14382459c8b7 26 m_hostname = hostname;
dgriffin65 15:14382459c8b7 27 m_ns = ns;
dgriffin65 15:14382459c8b7 28
dgriffin65 15:14382459c8b7 29 //default to google
dgriffin65 15:14382459c8b7 30 theDnsServer.set_ip_address("8.8.8.8"); // DNS
dgriffin65 15:14382459c8b7 31 theDnsServer.set_port(53); // DNS
dgriffin65 15:14382459c8b7 32 }
dgriffin65 15:14382459c8b7 33
dgriffin65 15:14382459c8b7 34 DNSClient::DNSClient(NetworkStack *ns, SocketAddress* pHost) : m_state(MYNETDNS_START), m_udp(NULL) {
dgriffin65 15:14382459c8b7 35 m_ns = ns;
dgriffin65 15:14382459c8b7 36
dgriffin65 15:14382459c8b7 37 //default to google
dgriffin65 15:14382459c8b7 38 theDnsServer.set_ip_address("8.8.8.8"); // DNS
dgriffin65 15:14382459c8b7 39 theDnsServer.set_port(53); // DNS
dgriffin65 15:14382459c8b7 40 }
dgriffin65 15:14382459c8b7 41
dgriffin65 15:14382459c8b7 42 DNSClient::~DNSClient() {
dgriffin65 15:14382459c8b7 43 if (m_udp) {
dgriffin65 15:14382459c8b7 44 delete m_udp;
dgriffin65 15:14382459c8b7 45 }
dgriffin65 15:14382459c8b7 46 }
dgriffin65 15:14382459c8b7 47
dgriffin65 15:14382459c8b7 48 int DNSClient::setup(NetworkStack *ns) {
dgriffin65 15:14382459c8b7 49 m_ns = ns;
dgriffin65 15:14382459c8b7 50 return 0;
dgriffin65 15:14382459c8b7 51 }
dgriffin65 15:14382459c8b7 52
dgriffin65 15:14382459c8b7 53 bool DNSClient::set_server(const char* serverip, int port) {
dgriffin65 15:14382459c8b7 54 theDnsServer.set_ip_address(serverip);
dgriffin65 15:14382459c8b7 55 theDnsServer.set_port(port);
dgriffin65 15:14382459c8b7 56 return true;
dgriffin65 15:14382459c8b7 57 }
dgriffin65 15:14382459c8b7 58
dgriffin65 15:14382459c8b7 59 void DNSClient::callback()
dgriffin65 15:14382459c8b7 60 {
dgriffin65 15:14382459c8b7 61 uint8_t buf[512];
dgriffin65 15:14382459c8b7 62 SocketAddress host;
dgriffin65 15:14382459c8b7 63 int len = m_udp->recvfrom(&host, (char*)buf, sizeof(buf));
dgriffin65 15:14382459c8b7 64 if (len < 0) {
dgriffin65 15:14382459c8b7 65 return;
dgriffin65 15:14382459c8b7 66 }
dgriffin65 15:14382459c8b7 67 if (memcmp(buf+0, m_id, 2) != 0) { //verify
dgriffin65 15:14382459c8b7 68 return;
dgriffin65 15:14382459c8b7 69 }
dgriffin65 15:14382459c8b7 70
dgriffin65 15:14382459c8b7 71 int rcode = response(buf, len);
dgriffin65 15:14382459c8b7 72 if (rcode == 0) {
dgriffin65 15:14382459c8b7 73 m_state = MYNETDNS_OK;
dgriffin65 15:14382459c8b7 74 } else {
dgriffin65 15:14382459c8b7 75 m_state = MYNETDNS_NOTFOUND;
dgriffin65 15:14382459c8b7 76 }
dgriffin65 15:14382459c8b7 77 }
dgriffin65 15:14382459c8b7 78
dgriffin65 15:14382459c8b7 79 int DNSClient::response(uint8_t buf[], int size) {
dgriffin65 15:14382459c8b7 80 int rcode = buf[3] & 0x0f;
dgriffin65 15:14382459c8b7 81 if (rcode != 0) {
dgriffin65 15:14382459c8b7 82 return rcode;
dgriffin65 15:14382459c8b7 83 }
dgriffin65 15:14382459c8b7 84 int qdcount = buf[4]<<8|buf[5];
dgriffin65 15:14382459c8b7 85 int ancount = buf[6]<<8|buf[7];
dgriffin65 15:14382459c8b7 86 int pos = 12;
dgriffin65 15:14382459c8b7 87 while(qdcount-- > 0) {
dgriffin65 15:14382459c8b7 88 dnsname qname(buf);
dgriffin65 15:14382459c8b7 89 pos = qname.decode(pos); // qname
dgriffin65 15:14382459c8b7 90 pos += 4; // qtype qclass
dgriffin65 15:14382459c8b7 91 }
dgriffin65 15:14382459c8b7 92 while(ancount-- > 0) {
dgriffin65 15:14382459c8b7 93 dnsname name(buf);
dgriffin65 15:14382459c8b7 94 pos = name.decode(pos); // name
dgriffin65 15:14382459c8b7 95 int type = buf[pos]<<8|buf[pos+1];
dgriffin65 15:14382459c8b7 96 pos += 8; // type class TTL
dgriffin65 15:14382459c8b7 97 int rdlength = buf[pos]<<8|buf[pos+1]; pos += 2;
dgriffin65 15:14382459c8b7 98 int rdata_pos = pos;
dgriffin65 15:14382459c8b7 99 pos += rdlength;
dgriffin65 15:14382459c8b7 100 if (type == 1) { // A record
dgriffin65 15:14382459c8b7 101 m_ip = (buf[rdata_pos]<<24) | (buf[rdata_pos+1]<<16) | (buf[rdata_pos+2]<<8) | buf[rdata_pos+3];
dgriffin65 15:14382459c8b7 102 sprintf(m_ipaddr, "%d.%d.%d.%d", buf[rdata_pos],buf[rdata_pos+1],buf[rdata_pos+2],buf[rdata_pos+3]);
dgriffin65 15:14382459c8b7 103 }
dgriffin65 15:14382459c8b7 104 #if DBG_DNS
dgriffin65 15:14382459c8b7 105 printf("%s", name.str.c_str());
dgriffin65 15:14382459c8b7 106 if (type == 1) {
dgriffin65 15:14382459c8b7 107 printf(" A %d.%d.%d.%d\n",
dgriffin65 15:14382459c8b7 108 buf[rdata_pos],buf[rdata_pos+1],buf[rdata_pos+2],buf[rdata_pos+3]);
dgriffin65 15:14382459c8b7 109 } else if (type == 5) {
dgriffin65 15:14382459c8b7 110 dnsname rdname(buf);
dgriffin65 15:14382459c8b7 111 rdname.decode(rdata_pos);
dgriffin65 15:14382459c8b7 112 printf(" CNAME %s\n", rdname.str.c_str());
dgriffin65 15:14382459c8b7 113 } else {
dgriffin65 15:14382459c8b7 114 printf(" TYPE:%d", type);
dgriffin65 15:14382459c8b7 115 printfBytes(" RDATA:", &buf[rdata_pos], rdlength);
dgriffin65 15:14382459c8b7 116 }
dgriffin65 15:14382459c8b7 117 #endif
dgriffin65 15:14382459c8b7 118 }
dgriffin65 15:14382459c8b7 119 return rcode;
dgriffin65 15:14382459c8b7 120 }
dgriffin65 15:14382459c8b7 121
dgriffin65 15:14382459c8b7 122 int DNSClient::query(uint8_t buf[], int size, const char* hostname) {
dgriffin65 15:14382459c8b7 123 const uint8_t header[] = {
dgriffin65 15:14382459c8b7 124 0x00,0x00,0x01,0x00, // id=0x0000 QR=0 rd=1 opcode=0 rcode=0
dgriffin65 15:14382459c8b7 125 0x00,0x01,0x00,0x00, // qdcount=1 ancount=0
dgriffin65 15:14382459c8b7 126 0x00,0x00,0x00,0x00};// nscount=0 arcount=0
dgriffin65 15:14382459c8b7 127 const uint8_t tail[] = {0x00,0x01,0x00,0x01}; // qtype=A qclass=IN
dgriffin65 15:14382459c8b7 128 memcpy(buf, header, sizeof(header));
dgriffin65 15:14382459c8b7 129 int t = rand();
dgriffin65 15:14382459c8b7 130 m_id[0] = t>>8;
dgriffin65 15:14382459c8b7 131 m_id[1] = t;
dgriffin65 15:14382459c8b7 132 memcpy(buf, m_id, 2);
dgriffin65 15:14382459c8b7 133 dnsname qname(buf);
dgriffin65 15:14382459c8b7 134 int pos = qname.encode(sizeof(header), (char*)hostname);
dgriffin65 15:14382459c8b7 135 memcpy(buf+pos, tail, sizeof(tail));
dgriffin65 15:14382459c8b7 136 pos += sizeof(tail);
dgriffin65 15:14382459c8b7 137 return pos;
dgriffin65 15:14382459c8b7 138 }
dgriffin65 15:14382459c8b7 139
dgriffin65 15:14382459c8b7 140 void DNSClient::resolve(const char* hostname) {
dgriffin65 15:14382459c8b7 141 if (m_udp == NULL) {
dgriffin65 15:14382459c8b7 142 m_udp = new UDPSocket;
dgriffin65 15:14382459c8b7 143 m_udp->open(m_ns);
dgriffin65 15:14382459c8b7 144 }
dgriffin65 15:14382459c8b7 145 m_udp->set_blocking(false);
dgriffin65 15:14382459c8b7 146 m_udp->bind(rand()&0x7fff);
dgriffin65 15:14382459c8b7 147 uint8_t buf[256];
dgriffin65 15:14382459c8b7 148 int size = query(buf, sizeof(buf), hostname);
dgriffin65 15:14382459c8b7 149 #if DBG_DNS
dgriffin65 15:14382459c8b7 150 printf("hostname:[%s]\n", hostname);
dgriffin65 15:14382459c8b7 151 printHex(buf, size);
dgriffin65 15:14382459c8b7 152 #endif
dgriffin65 15:14382459c8b7 153 m_udp->sendto(theDnsServer, (char*)buf, size);
dgriffin65 15:14382459c8b7 154 m_interval.reset();
dgriffin65 15:14382459c8b7 155 m_interval.start();
dgriffin65 15:14382459c8b7 156 }
dgriffin65 15:14382459c8b7 157
dgriffin65 15:14382459c8b7 158 void DNSClient::poll() {
dgriffin65 15:14382459c8b7 159 #if DBG_DNS
dgriffin65 15:14382459c8b7 160 printf("%p m_state: %d, m_udp: %p\n", this, m_state, m_udp);
dgriffin65 15:14382459c8b7 161 wait_ms(400);
dgriffin65 15:14382459c8b7 162 #endif
dgriffin65 15:14382459c8b7 163 switch(m_state) {
dgriffin65 15:14382459c8b7 164 case MYNETDNS_START:
dgriffin65 15:14382459c8b7 165 m_retry = 0;
dgriffin65 15:14382459c8b7 166 resolve(m_hostname);
dgriffin65 15:14382459c8b7 167 m_state = MYNETDNS_PROCESSING;
dgriffin65 15:14382459c8b7 168 break;
dgriffin65 15:14382459c8b7 169 case MYNETDNS_PROCESSING:
dgriffin65 15:14382459c8b7 170 break;
dgriffin65 15:14382459c8b7 171 case MYNETDNS_NOTFOUND:
dgriffin65 15:14382459c8b7 172 break;
dgriffin65 15:14382459c8b7 173 case MYNETDNS_ERROR:
dgriffin65 15:14382459c8b7 174 break;
dgriffin65 15:14382459c8b7 175 case MYNETDNS_OK:
dgriffin65 15:14382459c8b7 176 DBG2("m_retry=%d, m_interval=%d\n", m_retry, m_interval.read_ms());
dgriffin65 15:14382459c8b7 177 break;
dgriffin65 15:14382459c8b7 178 }
dgriffin65 15:14382459c8b7 179 if (m_interval.read_ms() > 1000) {
dgriffin65 15:14382459c8b7 180 m_interval.stop();
dgriffin65 15:14382459c8b7 181 DBG2("timeout m_retry=%d\n", m_retry);
dgriffin65 15:14382459c8b7 182 if (++m_retry >= 2) {
dgriffin65 15:14382459c8b7 183 m_state = MYNETDNS_ERROR;
dgriffin65 15:14382459c8b7 184 } else {
dgriffin65 15:14382459c8b7 185 resolve(m_hostname);
dgriffin65 15:14382459c8b7 186 m_state = MYNETDNS_PROCESSING;
dgriffin65 15:14382459c8b7 187 }
dgriffin65 15:14382459c8b7 188 }
dgriffin65 15:14382459c8b7 189 }
dgriffin65 15:14382459c8b7 190
dgriffin65 15:14382459c8b7 191 //tests for a valid IP address, returns 0 if invalid IP address format, returns ip address if valid
dgriffin65 15:14382459c8b7 192 static uint32_t
dgriffin65 15:14382459c8b7 193 isValidIP(const char* ip) {
dgriffin65 15:14382459c8b7 194 int i1, i2, i3, i4;
dgriffin65 15:14382459c8b7 195 int len = strlen(ip);
dgriffin65 15:14382459c8b7 196
dgriffin65 15:14382459c8b7 197 if (len < 7) return 0;
dgriffin65 15:14382459c8b7 198
dgriffin65 15:14382459c8b7 199 //count the number of dots, there must be 3
dgriffin65 15:14382459c8b7 200 int dotcount = 0;
dgriffin65 15:14382459c8b7 201 for (int i = 0; i < len; i++) {
dgriffin65 15:14382459c8b7 202 if (ip[i] == '.' ) dotcount++;
dgriffin65 15:14382459c8b7 203 }
dgriffin65 15:14382459c8b7 204
dgriffin65 15:14382459c8b7 205 //there must be exactly 3 dots
dgriffin65 15:14382459c8b7 206 if (dotcount != 3) return 0;
dgriffin65 15:14382459c8b7 207
dgriffin65 15:14382459c8b7 208 sscanf((char*)ip, "%d.%d.%d.%d", &i1, &i2, &i3, &i4);
dgriffin65 15:14382459c8b7 209
dgriffin65 15:14382459c8b7 210 if (strlen(ip) <= 16 && (i1 >= 0 && i1 <= 255) && (i2 >= 0 && i2 <= 255) &&
dgriffin65 15:14382459c8b7 211 (i3 >= 0 && i3 <= 255) && (i4 >= 0 && i4 <= 255)) {
dgriffin65 15:14382459c8b7 212 return ((i1<<24) | (i2<<16) | (i3<<8) | i4);
dgriffin65 15:14382459c8b7 213 }
dgriffin65 15:14382459c8b7 214 return 0;
dgriffin65 15:14382459c8b7 215 }
dgriffin65 15:14382459c8b7 216
dgriffin65 15:14382459c8b7 217 bool DNSClient::lookup(const char* hostname) {
dgriffin65 15:14382459c8b7 218 m_hostname = hostname;
dgriffin65 15:14382459c8b7 219
dgriffin65 15:14382459c8b7 220 uint32_t ip = isValidIP(hostname);
dgriffin65 15:14382459c8b7 221
dgriffin65 15:14382459c8b7 222 //check if hostname is an IP address
dgriffin65 15:14382459c8b7 223 if (ip > 0) {
dgriffin65 15:14382459c8b7 224 //if it is already an IP address just return immediately
dgriffin65 15:14382459c8b7 225 m_ip = ip;
dgriffin65 15:14382459c8b7 226 strcpy(m_ipaddr, hostname);
dgriffin65 15:14382459c8b7 227 m_state = MYNETDNS_OK;
dgriffin65 15:14382459c8b7 228 return true;
dgriffin65 15:14382459c8b7 229 }
dgriffin65 15:14382459c8b7 230
dgriffin65 15:14382459c8b7 231 m_state = MYNETDNS_START;
dgriffin65 15:14382459c8b7 232 while(1) {
dgriffin65 15:14382459c8b7 233 poll();
dgriffin65 15:14382459c8b7 234 callback();
dgriffin65 15:14382459c8b7 235 if (m_state != MYNETDNS_PROCESSING) {
dgriffin65 15:14382459c8b7 236 break;
dgriffin65 15:14382459c8b7 237 }
dgriffin65 15:14382459c8b7 238 }
dgriffin65 15:14382459c8b7 239
dgriffin65 15:14382459c8b7 240 if (m_udp) {
dgriffin65 15:14382459c8b7 241 delete m_udp;
dgriffin65 15:14382459c8b7 242 m_udp = NULL;
dgriffin65 15:14382459c8b7 243 }
dgriffin65 15:14382459c8b7 244 return m_state == MYNETDNS_OK;
dgriffin65 15:14382459c8b7 245 }