Example

TX configuration code example

This TX configuration code example is an excerpt from the file replay4ga_example.c, which is included in the product release package.

uint32_t status;
NtNetStreamFile_t hNetFile;     // Handle to the File stream
NtNetBuf_t hNetBufFile;         // Net buffer container. Used to return segments from the file stream
NtConfigStream_t hStream;       // Config stream handle
NtConfig_t configRead;          // Config stream data container
NtConfig_t configWrite;         // Config stream data container
struct NtNetBuf_s pktNetBuf;    // Packet netbuf structure.
uint8_t adapterNo ;             // Adapter no
uint64_t firstPacketTS=0;       // Timestamp of first packet
uint64_t adapterTS=0;           // Timestamp on the adapter
uint64_t timeDelta=0;           // Calculated time delta

// default setup
#define PORT        0

. . .

// Open the capture file to replay (captured with the capture example)
if((status = NT_NetFileOpen(&hNetFile, "FileStream", NT_NET_INTERFACE_SEGMENT, "capfile.ntcap")) != NT_SUCCESS) {
  // Error handling
}

// Read one segment from the file to get the first packet timestamp
if ((status = NT_NetFileGet(hNetFile, &hNetBufFile)) != NT_SUCCESS) {
  // Error handling
}
_nt_net_build_pkt_netbuf(hNetBufFile, &pktNetBuf);
firstPacketTS = NT_NET_GET_PKT_TIMESTAMP(&pktNetBuf) * 10; // Convert 10ns ticks to 1ns

// Close the file again. We will open it again later to actually transmit packets.
NT_NetFileClose(hNetFile);

// Open the config stream
if((status = NT_ConfigOpen(&hStream, "Replay")) != NT_SUCCESS) {
  // Error handling
}

. . .

// Read the adapter time
configRead.parm = NT_CONFIG_PARM_ADAPTER_TIMESTAMP;
configRead.u.timestampRead.adapter = adapterNo;
if ((status = NT_ConfigRead(hConfig, &configRead)) != NT_SUCCESS) {
  // Error handling
}
adapterTS = configRead.u.timestampRead.data.nativeUnixTs * 10; // Convert 10ns ticks to 1ns

// Calculate time delta - we add 1 second to give ourselves some headroom
timeDelta = (adapterTS - firstPacketTS) + 1000000000;

// Configure transmit on timestamp
configWrite.parm = NT_CONFIG_PARM_PORT_TRANSMIT_ON_TIMESTAMP;
configWrite.u.transmitOnTimestamp.portNo = (uint8_t) PORT;     // the TX port to configure
configWrite.u.transmitOnTimestamp.data.timeDelta = timeDelta;  // calculated offset in ns 
configWrite.u.transmitOnTimestamp.data.enable = true;          // enable transmit on time stamp
configWrite.u.transmitOnTimestamp.data.forceTxOnTs = true;     // ignore TxNow

if((status = NT_ConfigWrite(hStream, &configWrite)) != NT_SUCCESS) {
  // Error handling
}

. . .