cvi的UDP通信

#define READER_PORT 17224 // arbitrarily chosen from the Dynamic/Private port range (49152-65535)
#define MULTICAST_ADDRESS "239.194.0.217" // arbitrarily selected from the multicast address range (224.0.0.0-239.255.255.255)

//发送端

int main (int argc, char *argv[])
{
int error = 0;

if (InitCVIRTE (0, argv, 0) == 0)
return -1; /* out of memory */
if ((panelHandle = LoadPanel (0, "UDPWriter.uir", PANEL)) < 0)
return -1;

// Initialize some additional UI settings.
errChk (SetCtrlAttribute(panelHandle, PANEL_DATA, ATTR_MAX_ENTRY_LENGTH, MAX_DATA_INPUT_LENGTH));
errChk (SetCtrlAttribute(panelHandle, PANEL_UNICAST_IP, ATTR_MAX_ENTRY_LENGTH, MAX_IP_INPUT_LENGTH));
errChk (SetCtrlVal(panelHandle, PANEL_MULTICAST_IP, MULTICAST_ADDRESS));

// Create a UDP channel from which to send messages. The port number can be any available
// port since we expect only to write, not receive data.

//创建一个UDP通道对象，使用该对象发送和/或接收UDP数据报。
errChk (CreateUDPChannel(UDP_ANY_LOCAL_PORT, &writerChannel));

DisplayPanel (panelHandle);
RunUserInterface ();
DiscardPanel (panelHandle);
Error:
if (writerChannel)
DisposeUDPChannel(writerChannel);
if (error < 0)
MessagePopup("Error", GetGeneralErrorString(error));
return 0;
}

int CVICALLBACK Send (int panel, int control, int event,
void *callbackData, int eventData1, int eventData2)
{
int error = 0;

if (event == EVENT_COMMIT)
{
char data[MAX_DATA_INPUT_LENGTH + 1];
char destAddr[MAX_IP_INPUT_LENGTH + 1];
int unicast, multicast, broadcast;

// errChk (GetCtrlVal(panel, PANEL_DATA, data));
memset(data, 1, 139);

errChk (GetCtrlVal(panel, PANEL_UNICAST, &unicast));
errChk (GetCtrlVal(panel, PANEL_MULTICAST, &multicast));
errChk (GetCtrlVal(panel, PANEL_BROADCAST, &broadcast));
// Depending on which radio button is selected, the message is addressed to one of:
// (1) a specific IP address or DNS-resolvable host name (Unicast),
// (2) a predetermined multicast address to which multiple readers may be subscribed (Multicast),
// (3) the broadcast address, which propogates to every computer on the subnet (Broadcast).
if (unicast)
errChk (GetCtrlVal(panel, PANEL_UNICAST_IP, destAddr));
else if (multicast)
errChk (GetCtrlVal(panel, PANEL_MULTICAST_IP, destAddr));
else if (broadcast)
strcpy(destAddr, UDP_LAN_BROADCAST_ADDR);

// Write the message to a predetermined port number on which all readers will listening.
errChk (UDPWrite(writerChannel, READER_PORT, destAddr, data, strlen(data) + 1));
}
Error:
if (error < 0)
MessagePopup("Error", GetGeneralErrorString(error));
return 0;
}

/// HIFN Handles mutual exclusivity of the Unicast, Multicast, and Broadcast radio buttons.
int CVICALLBACK RadioCallback (int panel, int control, int event,
void *callbackData, int eventData1, int eventData2)
{
int error = 0;

if (event == EVENT_COMMIT)
{
int on;
errChk (GetCtrlVal(panel, control, &on));
if (!on)
{
// Ensure one radio button is always selected.
errChk (SetCtrlVal(panel, control, 1));
}
else
{
if (control != PANEL_UNICAST)
errChk (SetCtrlVal(panel, PANEL_UNICAST, 0));
if (control != PANEL_MULTICAST)
errChk (SetCtrlVal(panel, PANEL_MULTICAST, 0));
if (control != PANEL_BROADCAST)
errChk (SetCtrlVal(panel, PANEL_BROADCAST, 0));
}
}
Error:
if (error < 0)
MessagePopup("Error", GetGeneralErrorString(error));
return 0;
}

//接收端

//-----------------------------------------------------------------------------
// Program entry point
//-----------------------------------------------------------------------------
int main (int argc, char *argv[])
{
int error = 0;

if (InitCVIRTE (0, argv, 0) == 0)
return -1; /* out of memory */
if ((panelHandle = LoadPanel (0, "UDPReader.uir", PANEL)) < 0)
return -1;

errChk (SetCtrlVal(panelHandle, PANEL_MULTICAST_IP, MULTICAST_ADDRESS));

errChk (CreateUDPChannelConfig(READER_PORT, UDP_ANY_ADDRESS, 0, UDPCallback, NULL, &readerChannel));

DisplayPanel (panelHandle);
RunUserInterface ();
DiscardPanel (panelHandle);
Error:
if (readerChannel)
DisposeUDPChannel(readerChannel);
if (error < 0)
MessagePopup("Error", GetGeneralErrorString(error));
return 0;
}

//-----------------------------------------------------------------------------
// UDP callback function
//-----------------------------------------------------------------------------
/// HIFN This function is called when data arrives on the UDP channel. It is up
/// HIFN to this function to read the waiting data.
/// HIPAR channel/The channel that has waiting data.
/// HIPAR eventType/The type of UDP event. UDP_DATAREADY is the only event type.
/// HIPAR errCode/Non-zero indicates an error that occurred with the event.
/// HIPAR callbackData/Callback data (if any) that was assigned on the channel.
int CVICALLBACK UDPCallback (unsigned channel, int eventType, int errCode, void *callbackData)
{
int error = 0, i, size;
unsigned char *msg = NULL;

if (eventType == UDP_DATAREADY)
{
char srcAddr[16];
unsigned int srcPort;
char msgSourceString[16 + 10];

// Pass NULL as the input buffer to determine the size of the arrived data.
errChk (size = UDPRead(channel, NULL, 0, UDP_DO_NOT_WAIT, NULL, NULL));

       printf("size: %d\r\n", size);
nullChk (msg = malloc(size));

// Read the waiting message into the allocated buffer.
errChk (size = UDPRead(channel, msg, size, UDP_DO_NOT_WAIT, &srcPort, srcAddr));

   //   printf("\r\n");
       for(i = 0; i < size; i++)
       {
           printf(" %d", msg[i]);
       }

       printf("\r\n");

// Display the message, preceeded by the sender's IP address and port number.
sprintf(msgSourceString, "[%s:%d]: ", srcAddr, srcPort);
errChk (SetCtrlVal(panelHandle, PANEL_TEXTBOX, msgSourceString));
errChk (SetCtrlVal(panelHandle, PANEL_TEXTBOX, msg));
errChk (SetCtrlVal(panelHandle, PANEL_TEXTBOX, "\n"));
}
Error:
if (error < 0)
MessagePopup("Error", GetGeneralErrorString(error));;
if (msg)
free(msg);
return 0;
}

//-----------------------------------------------------------------------------
// UI callback functions
//-----------------------------------------------------------------------------
/// HIFN Toggles subscription to a predefined multicast address. When subscribed,
/// HIFN this channel will be forwarded a copy of any message addressed to
/// HIFN the multicast address and the reader's port number.
int CVICALLBACK DoMulticast (int panel, int control, int event,
void *callbackData, int eventData1, int eventData2)
{
int error = 0;

if (event == EVENT_COMMIT)
{
int on;
char ipAddr[16];

errChk (GetCtrlVal(panel, control, &on));
errChk (GetCtrlVal(panel, PANEL_MULTICAST_IP, ipAddr));

if (on)
errChk (UDPMulticastSubscribe(readerChannel, ipAddr, NULL));
else
errChk (UDPMulticastUnsubscribe(readerChannel, ipAddr, NULL));
}
Error:
if (error < 0)
MessagePopup("Error", GetGeneralErrorString(error));
return 0;
}

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