net/transmit_on_timestamp/transmit_on_timestamp_example.c

Reference Documentation

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IntelĀ® PAC
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Reference Information
Napatech Software Suite: net/transmit_on_timestamp/transmit_on_timestamp_example.c
net/transmit_on_timestamp/transmit_on_timestamp_example.c

Description

This source file is an example of how to transmit packets on timestamp using the packet interface in NTAPI. The example will transmit 100000 packets with a size of 296 bytes from port 0 at a rate of approximately 5 Mb/s. The packet contains an incrementing 32bit pattern.

The transmit on timestamp functionality is also available in segment mode. See the net/transmit_segment/transmit_segment_example.c example code to see how to use the segment interface.

The following NTAPI functions are used:

Prerequisites

  • This example is only compatible with adapters supporting 4GA transmit on timestamp.
  • The ntservice.ini must have at least one HostBuffersTx defined. Below is an example of a minimum ini-file. It will create a 4MB TX hostbuffer from NUMA node 0.
[System]
TimestampFormat = NATIVE
[Adapter0]
AdapterType = NT20E2
BusId = 00:0a:00.00
HostBuffersTx = [1,4,0]

Program flow

The following is required to transmit packages:

  • #include/nt.h - Applications/Tools only need to include nt.h to obtain prototypes, macros etc. from NTAPI.
  • NT_Init(NTAPI_VERSION) - Initialize the NTAPI library. NTAPI_VERSION is a define that describes the version of the API described in the header files included by nt.h. NT_Init() will ask the NTAPI library to convert return data to the NTAPI_VERSION if possible. This will ensure that applications can run on NTAPI libraries of newer versions.
  • NT_ConfigOpen() - Open the config stream.
  • NT_ConfigRead() - Use the config stream to read the current adapter time.
  • NT_ConfigWrite() - Use the config stream to configure transmit on timestamp, using the retrieved adapter time.
  • NT_NetTxOpen() - Open a hostbuffer than can transmit packets to port 0.
  • NT_NetTxGet() - Get an empty tx buffer. This will get a 296 byte wire length packet buffer that will be sent onto port 0 when the packet buffer is released, and the timestamp has been reached on the adapter.
  • NT_NetTxRelease() - Release the tx packet buffer. Once a tx buffer is released it will be transmitted
  • NT_ConfigRead() - Read the adapter timestamp to check if the last packet should have been transmitted. We need to do this in order to avoid disabling transmit on timestamp too early.
  • NT_ConfigWrite() - Disable transmit on timestamp.
  • NT_NetTxClose() - Close the TX stream.
  • NT_Done() - Close down the NTAPI library.

Code

/*
*
* Copyright 2020 Napatech A/S. All Rights Reserved.
*
* 1. Copying, modification, and distribution of this file, or executable
* versions of this file, is governed by the terms of the Napatech Software
* license agreement under which this file was made available. If you do not
* agree to the terms of the license do not install, copy, access or
* otherwise use this file.
*
* 2. Under the Napatech Software license agreement you are granted a
* limited, non-exclusive, non-assignable, copyright license to copy, modify
* and distribute this file in conjunction with Napatech SmartNIC's and
* similar hardware manufactured or supplied by Napatech A/S.
*
* 3. The full Napatech Software license agreement is included in this
* distribution, please see "NP-0405 Napatech Software license
* agreement.pdf"
*
* 4. Redistributions of source code must retain this copyright notice,
* list of conditions and the following disclaimer.
*
* THIS SOFTWARE IS PROVIDED "AS IS" WITHOUT ANY WARRANTIES, EXPRESS OR
* IMPLIED, AND NAPATECH DISCLAIMS ALL IMPLIED WARRANTIES INCLUDING ANY
* IMPLIED WARRANTY OF TITLE, MERCHANTABILITY, NONINFRINGEMENT, OR OF
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*
*
*/
/**
* @example net/transmit_on_timestamp/transmit_on_timestamp_example.c
* @section transmit_on_timestamp_example_description Description
*
* This source file is an example of how to transmit packets on timestamp
* using the packet interface in NTAPI. The example will transmit 100000
* packets with a size of 296 bytes from port 0 at a rate of approximately
* 5 Mb/s. The packet contains an incrementing 32bit pattern.
*
* The transmit on timestamp functionality is also available in segment mode.
* See the @ref net/transmit_segment/transmit_segment_example.c example code
* to see how to use the segment interface.
*
* The following NTAPI functions are used:
* - @ref NT_Init()
* - @ref NT_ConfigOpen()
* - @ref NT_ConfigRead()
* - @ref NT_ConfigWrite()
* - @ref NT_ConfigClose()
* - @ref NT_NetTxOpen()
* - @ref NT_NetTxGet()
* - @ref NT_NET_SET_PKT_TIMESTAMP()
* - @ref NT_NET_GET_PKT_L2_PTR()
* - @ref NT_NetTxRelease()
* - @ref NT_NetTxClose()
* - @ref NT_Done()
* - @ref NT_ExplainError()
*
* @section transmit_on_timestamp_example_prerequisites Prerequisites
* - This example is only compatible with adapters supporting 4GA transmit on
* timestamp.
* - The ntservice.ini must have at least one HostBuffersTx defined. Below is
* an example of a minimum ini-file. It will create a 4MB TX hostbuffer from
* NUMA node 0.
*
* @code
* [System]
* TimestampFormat = NATIVE
*
* [Adapter0]
* AdapterType = NT20E2
* BusId = 00:0a:00.00
* HostBuffersTx = [1,4,0]
* @endcode
*
* @section transmit_on_timestamp_example_flow Program flow
* @{
* The following is required to transmit packages:
* - \#include/nt.h - Applications/Tools only need to include @ref
* nt.h to obtain prototypes, macros etc. from NTAPI.
* - @ref NT_Init(@ref NTAPI_VERSION) - Initialize the NTAPI
* library. @ref NTAPI_VERSION is a define that describes the version
* of the API described in the header files included by @ref
* nt.h. NT_Init() will ask the NTAPI library to convert return data
* to the @ref NTAPI_VERSION if possible. This will ensure that
* applications can run on NTAPI libraries of newer versions.
* - @ref NT_ConfigOpen() - Open the config stream.
* - @ref NT_ConfigRead() - Use the config stream to read the current adapter
* time.
* - @ref NT_ConfigWrite() - Use the config stream to configure transmit on
* timestamp, using the retrieved adapter time.
* - @ref NT_NetTxOpen() - Open a hostbuffer than can transmit packets to port 0.
* - @ref NT_NetTxGet() - Get an empty tx buffer. This will get a 296 byte
* wire length packet buffer that will be sent onto port 0 when the packet
* buffer is released, and the timestamp has been reached on the adapter.
* - @ref NT_NET_GET_PKT_L2_PTR() is used to get the L2 pointer to the tx
* buffer, this is where the payload is placed.
* - @ref NT_NET_SET_PKT_TIMESTAMP() is used to set the packet timestamp.
* - @ref NT_NetTxRelease() - Release the tx packet buffer. Once a tx
* buffer is released it will be transmitted
* - @ref NT_ConfigRead() - Read the adapter timestamp to check if the last
* packet should have been transmitted. We need to do this in order to avoid
* disabling transmit on timestamp too early.
* - @ref NT_ConfigWrite() - Disable transmit on timestamp.
* - @ref NT_NetTxClose() - Close the TX stream.
* - @ref NT_Done() - Close down the NTAPI library.
*
*<hr>
* @section transmit_on_timestamp_example_code Code
* @}
*/
#include <nt.h>
#if defined(__linux__) || defined(__FreeBSD__)
#include <unistd.h> // sleep()
#elif defined(WIN32) || defined (WIN64)
#include <winsock2.h>
#endif
// default TX packet test setup
#define PACKETS 100000
#define PACKET_SIZE 296 // Packet size to transmit (incl crc.)
#define PORT 0
#define ADAPTER 0
// printError is a simple convenience function for printing an NTAPI error
// message to stderr.
static void printError(const char *prefix, int errorCode) {
NT_ExplainError(errorCode, errorBuffer, sizeof errorBuffer);
fprintf(stderr, "%s: %s\n", prefix, errorBuffer);
}
int main(void)
{
//
// Initialize the API. This also checks if we are compatible with the
// installed library version.
//
int status;
if((status = NT_Init(NTAPI_VERSION)) != NT_SUCCESS) {
printError("NT_Init() failed", status);
return -1;
}
//
// Open the config stream, in order to retrieve the adapter timestamp and
// to configure the transmit on timestamp functionality. We configure
// transmit on timestamp in such a way that a packet with timestamp 0 will
// transmit in approximately one second from this point.
//
NtConfig_t config;
if ((status = NT_ConfigOpen(&hConfig, "replay")) != NT_SUCCESS) {
printError("NT_ConfigOpen() failed", status);
return -1;
}
if ((status = NT_ConfigRead(hConfig, &config)) != NT_SUCCESS) {
printError("NT_ConfigRead() failed", status);
return -1;
}
// Store adapter timestamp, converted from 10ns ticks to 1ns
uint64_t adapterTS = config.u.timestampRead.data.nativeUnixTs * 10;
// Configure transmit on timestamp. In scenarios where a packet descriptor
// that does not contain a TXNOW bit is used, such as when transmitting PCAP,
// forceTxOnTs must be set to true. However, this example uses NT
// descriptors, and can thus use the TXNOW bit.
config.u.transmitOnTimestamp.portNo = (uint8_t)PORT;
config.u.transmitOnTimestamp.data.timeDelta = adapterTS + 1000000000;
if ((status = NT_ConfigWrite(hConfig, &config)) != NT_SUCCESS) {
printError("NT_ConfigWrite() failed", status);
return -1;
}
//
// Open a TX stream
//
if ((status = NT_NetTxOpen(&hNetTx, "transmit_on_timestamp_example_txstream",
(1<<PORT), NT_NETTX_NUMA_ANY_HB, 0)) != NT_SUCCESS) {
printError("NT_NetTxOpen() failed", status);
return -1;
}
//
// Retrieve a packet buffer, fill it, and repeat until we have transmitted
// the requested amount of packets. The timestamp will be set so that the
// adapter will transmit at approximately 5 Mb/s.
//
printf("Commencing transmission\n");
NtNetBuf_t hNetBufTx;
uint64_t timestamp = 0;
int numPackets = 0;
for (numPackets = 0; numPackets < PACKETS; numPackets++) {
// Get a packet TX buffer for this tx stream and port, without timeout
if ((status = NT_NetTxGet(hNetTx, &hNetBufTx, PORT, PACKET_SIZE,
NT_NETTX_PACKET_OPTION_DEFAULT, -1)) != NT_SUCCESS) {
printError("NT_NetTxGet() failed", status);
return -1;
}
// Set the timestamp. Note that for the NT descriptor, this is in 10ns
// ticks. The descriptor has been cleared, so TXNOW is set to 0. If one
// wishes to send a packet as soon as possible while transmit on timestamp
// is enabled, use NT_NET_SET_PKT_TXNOW to set TXNOW to 1.
NT_NET_SET_PKT_TIMESTAMP(hNetBufTx, timestamp);
timestamp += 50000;
// Fill the packet with an incrementing payload. Note that this will result
// in a garbage ethernet frame.
uint32_t *ptr = (uint32_t*)NT_NET_GET_PKT_L2_PTR(hNetBufTx);
for (int i = 0; i < PACKET_SIZE/4; i++) {
*(ptr+i) = i;
}
// Release the TX buffer to commit the packet. It will transmit once the
// timestamp is reached, or when transmit on timestamp is disabled.
if ((status = NT_NetTxRelease(hNetTx, hNetBufTx)) != NT_SUCCESS) {
printError("NT_NetTxRelease() failed", status);
return -1;
}
}
//
// Wait for all packets to be transmitted. There are multiple ways to do
// this, but in this example, we read the adapter timestamp in a loop, and
// compare it to the value of our timestamp variable from the loop above.
//
printf("Waiting for transmission to end\n");
uint64_t newAdapterTS = adapterTS;
do {
#if defined(__linux__) || defined(__FreeBSD__)
sleep(1);
#elif defined(WIN32) || defined (WIN64)
Sleep(1000); // sleep 1000 milliseconds = 1 second
#endif
if ((status = NT_ConfigRead(hConfig, &config)) != NT_SUCCESS) {
printError("NT_ConfigRead() failed", status);
return -1;
}
newAdapterTS = config.u.timestampRead.data.nativeUnixTs * 10;
} while (newAdapterTS <= (adapterTS + timestamp));
//
// Disable transmit on timestamp. If any packets are left in the buffera this
// point, they will transmit unhindered at line rate.
//
config.u.transmitOnTimestamp.portNo = (uint8_t)PORT;
config.u.transmitOnTimestamp.data.enable = false;
if ((status = NT_ConfigWrite(hConfig, &config)) != NT_SUCCESS) {
printError("NT_ConfigWrite() failed", status);
return -1;
}
//
// Terminate
//
printf("Done: %d packets sent\n", numPackets);
// Close the TX stream
NT_NetTxClose(hNetTx);
// Close the API
return 0;
}