bool UDPSocket::readEndpoint(Endpoint & ep) { char recv[256]; int begin = 0; int end = 0; string str; string addr; int port; if (!endpoint_read) { if (!wifi->sendCommand("get ip\r", NULL, recv)) return false; wifi->exit(); str = recv; begin = str.find("HOST="); end = str.find("PROTO="); if (begin != string::npos && end != string::npos) { str = str.substr(begin + 5, end - begin - 5); int pos = str.find(":"); if (pos != string::npos) { addr = str.substr(0, pos); port = atoi(str.substr(pos + 1).c_str()); ep.set_address(addr.c_str(), port); endpoint_read = true; wifi->flush(); return true; } } wifi->flush(); } return false; }
int main() { bool result = false; EthernetInterface eth; eth.init(); //Use DHCP eth.connect(); printf("UDP client IP Address is %s\n", eth.getIPAddress()); UDPSocket sock; sock.init(); Endpoint nist; nist.set_address(HTTP_SERVER_NAME, HTTP_SERVER_PORT); char out_buffer[] = "plop"; // Does not matter sock.sendTo(nist, out_buffer, sizeof(out_buffer)); union { char in_buffer_tab[4]; unsigned int in_buffer_uint; }; const int n = sock.receiveFrom(nist, in_buffer_tab, sizeof(in_buffer_tab)); if (n > 0) { result = true; const unsigned int timeRes = ntohl(in_buffer_uint); const float years = timeRes / 60.0 / 60.0 / 24.0 / 365; printf("UDP: Received %d bytes from server %s on port %d\r\n", n, nist.get_address(), nist.get_port()); printf("UDP: %u seconds since 01/01/1900 00:00 GMT ... %s\r\n", timeRes, timeRes > 0 ? "[OK]" : "[FAIL]"); printf("UDP: %.2f years since 01/01/1900 00:00 GMT ... %s\r\n", years, timeRes > YEARS_TO_PASS ? "[OK]" : "[FAIL]"); if (years < YEARS_TO_PASS) { result = false; } } sock.close(); eth.disconnect(); notify_completion(result); return 0; }
NTPResult NTPClient::setTime(const char* host, uint16_t port, uint32_t timeout) { #ifdef __DEBUG__ time_t ctTime; ctTime = time(NULL); DBG("Time is set to (UTC): %s", ctime(&ctTime)); #endif //Create & bind socket DBG("Binding socket"); m_sock.bind(0); //Bind to a random port m_sock.set_blocking(false, timeout); //Set not blocking struct NTPPacket pkt; //Now ping the server and wait for response DBG("Ping"); //Prepare NTP Packet: pkt.li = 0; //Leap Indicator : No warning pkt.vn = 4; //Version Number : 4 pkt.mode = 3; //Client mode pkt.stratum = 0; //Not relevant here pkt.poll = 0; //Not significant as well pkt.precision = 0; //Neither this one is pkt.rootDelay = 0; //Or this one pkt.rootDispersion = 0; //Or that one pkt.refId = 0; //... pkt.refTm_s = 0; pkt.origTm_s = 0; pkt.rxTm_s = 0; pkt.txTm_s = htonl( NTP_TIMESTAMP_DELTA + time(NULL) ); //WARN: We are in LE format, network byte order is BE pkt.refTm_f = pkt.origTm_f = pkt.rxTm_f = pkt.txTm_f = 0; Endpoint outEndpoint; if( outEndpoint.set_address(host, port) < 0) { m_sock.close(); return NTP_DNS; } //Set timeout, non-blocking and wait using select int ret = m_sock.sendTo( outEndpoint, (char*)&pkt, sizeof(NTPPacket) ); if (ret < 0 ) { ERR("Could not send packet"); m_sock.close(); return NTP_CONN; } //Read response Endpoint inEndpoint; DBG("Pong"); do { ret = m_sock.receiveFrom( inEndpoint, (char*)&pkt, sizeof(NTPPacket) ); //FIXME need a DNS Resolver to actually compare the incoming address with the DNS name if(ret < 0) { ERR("Could not receive packet"); m_sock.close(); return NTP_CONN; } } while( strcmp(outEndpoint.get_address(), inEndpoint.get_address()) != 0 ); if(ret < sizeof(NTPPacket)) //TODO: Accept chunks { ERR("Receive packet size does not match"); m_sock.close(); return NTP_PRTCL; } if( pkt.stratum == 0) //Kiss of death message : Not good ! { ERR("Kissed to death!"); m_sock.close(); return NTP_PRTCL; } //Correct Endianness pkt.refTm_s = ntohl( pkt.refTm_s ); pkt.refTm_f = ntohl( pkt.refTm_f ); pkt.origTm_s = ntohl( pkt.origTm_s ); pkt.origTm_f = ntohl( pkt.origTm_f ); pkt.rxTm_s = ntohl( pkt.rxTm_s ); pkt.rxTm_f = ntohl( pkt.rxTm_f ); pkt.txTm_s = ntohl( pkt.txTm_s ); pkt.txTm_f = ntohl( pkt.txTm_f ); //Compute offset, see RFC 4330 p.13 uint32_t destTm_s = (NTP_TIMESTAMP_DELTA + time(NULL)); int64_t offset = ( (int64_t)( pkt.rxTm_s - pkt.origTm_s ) + (int64_t) ( pkt.txTm_s - destTm_s ) ) / 2; //Avoid overflow DBG("Sent @%ul", pkt.txTm_s); DBG("Offset: %lld", offset); //Set time accordingly set_time( time(NULL) + offset ); #ifdef __DEBUG__ ctTime = time(NULL); DBG("Time is now (UTC): %s", ctime(&ctTime)); #endif m_sock.close(); return NTP_OK; }