C++ Endpoint::set_address方法代码示例

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 );
//.........这里部分代码省略.........