trex_api.py

#!/usr/bin/python

# Copyright (c) 2016 Cisco and/or its affiliates.
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at:
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

"""This script uses T-REX stateless API to drive t-rex instance.

Requirements:
- T-REX: https://github.com/cisco-system-traffic-generator/trex-core
 - compiled and running T-REX process (eg. ./t-rex-64 -i -c 4)
 - trex_stl_lib.api library
- Script must be executed on a node with T-REX instance
- 2 interfaces must be configured in configuretion file /etc/trex_cfg.yaml

##################### Example of /etc/trex_cfg.yaml ##########################
- port_limit      : 2 # numbers of ports to use
  version         : 2
  interfaces      : ["84:00.0","84:00.1"] # PCI address of interfaces
  port_info       :  # set eth mac addr
          - dest_mac        :   [0x90,0xe2,0xba,0x1f,0x97,0xd5]  # port 0
            src_mac         :   [0x90,0xe2,0xba,0x1f,0x97,0xd4]
          - dest_mac        :   [0x90,0xe2,0xba,0x1f,0x97,0xd4]  # port 1
            src_mac         :   [0x90,0xe2,0xba,0x1f,0x97,0xd5]
##############################################################################

Functionality:
1. Configure traffic on running T-REX instance
2. Clear statistics on all ports
3. Ctart traffic with specified duration
4. Print statistics to stdout

"""

import sys


sys.path.insert(0, "trex_client/stl/")
from trex_stl_lib.api import *

# create client
client = STLClient()


def create_stream(mac_dest, src_n, packet_size=60, port_n=0):
    # create a base packet and pad it to size
    # size = 60  # no FCS

    mac_src = "00:00:dd:dd:ae:11"
    base_pkt = Ether(dst=mac_dest, src=mac_src)/IP(src="10.195.115.232", dst="10.195.115.234")/UDP(dport=12,sport=1025)
    pad = max(0, packet_size - len(base_pkt)) * 'x'

    min_mac_value = (src_n * port_n)
    max_mac_value = min_mac_value + src_n

    print min_mac_value, max_mac_value

    vm = STLScVmRaw(
        [STLVmFlowVar(name="mac_src", min_value=min_mac_value, max_value=max_mac_value, size=4, op="inc"),
         STLVmWrFlowVar(fv_name="mac_src", pkt_offset=10)  # write it to LSB of SRC
         ]
        )

    return STLStream(packet=STLPktBuilder(pkt=base_pkt / pad, vm=vm),
                     mode=STLTXCont(pps=10))


def is_running():
    return client.is_connected()


# Get traffic generation session's details
def get_stats():
    if is_running():
        return client.get_stats()
    else:
        return {}


def start_traffic(pkts_n, duration, pps, mac_dest, src_n, packet_size, mult):
    """Run the traffic with specific parameters.

    :param pkts_n: Number of packets/ports
    :param duration: Duration of traffic run in seconds (-1=infinite).
    :param pps: Rate of traffic run [percentage, pps, bps].
    :param mac_dest: destination MAC address
    :param src_n: NUmber of source MAC addresses
    :param packet_size: packet size in bits
    :param mult: multiplier for pps

    :type pkts_n: int
    :type duration: int
    :type pps: string

    :return: nothing
    """

    try:

        port_list = range(0, pkts_n)
        rate = str(pps * mult) + "pps"

        # connect to server
        client.connect()

        # prepare our ports (my machine has 0 <--> 1 with static route)
        client.reset(ports=port_list)

        for idx in range(0, pkts_n):
            stream = create_stream(mac_dest=mac_dest,
                                   src_n=src_n,
                                   port_n=idx,
                                   packet_size=packet_size)
            client.add_streams(stream, ports=[idx])
            print "*** idx = ", idx

        # clear the stats before injecting
        client.clear_stats()

        # choose rate and start traffic
        client.start(ports=port_list, mult=rate, duration=duration)

    except STLError as ex_error:
        print_error(str(ex_error))
        sys.exit(1)


def stop_traffic():
    # graceful stop
    if client.is_connected():
        active_ports = client.get_active_ports()
        if len(active_ports) > 0:
            client.stop(active_ports)
        client.disconnect()


def print_error(msg):
    """Print error message on stderr.

    :param msg: Error message to print.
    :type msg: string
    :return: nothing
    """

    sys.stderr.write(msg+'\n')