[PATCH v2 3/4] lnst.TRex Use stl compatible modules to generate streams

[Adrian Moreno]

Use external, dynamically loaded modules to generate the streams that
get added to the client.

The module API is compatible with TRex's STL [1] to ease prototyping.

[1] https://trex-tgn.cisco.com/trex/doc/trex_stateless.html

Signed-off-by: Adrian Moreno <amorenoz(a)redhat.com&gt;
---
 lnst/External/TRex/TRexLib.py   | 37 +++++++++++++++-----------------
 lnst/External/TRex/UDPSimple.py | 38 +++++++++++++++++++++++++++++++++
 2 files changed, 55 insertions(+), 20 deletions(-)
 create mode 100644 lnst/External/TRex/UDPSimple.py

diff --git a/lnst/External/TRex/TRexLib.py b/lnst/External/TRex/TRexLib.py
index 68e6289..39b56f9 100644
--- a/lnst/External/TRex/TRexLib.py
+++ b/lnst/External/TRex/TRexLib.py
@@ -1,3 +1,4 @@
+import importlib
 import os
 import sys
 import time
@@ -11,7 +12,8 @@ TREX_CLI_DEFAULT_PARAMS = {
         "warmup_time": 5,
         "server_hostname": "localhost",
         "trex_stl_path": 'trex_client/interactive',
-        "msg_size": 64
+        "msg_size": 64,
+        "module": "UDPSimple"
         }
 
 class TRexCli:
@@ -28,6 +30,7 @@ class TRexCli:
         - warmup_time (int): Time to wait before starting to take measurements. Default:
5
         - server_hostname (str): Host where the server is running.
         - msg_size (int): Message size
+        - module(str): The python module to call for stream creation. Default
(UDPSimple)
     """
     trex_stl_path = 'trex_client/interactive'
 
@@ -69,31 +72,25 @@ class TRexCli:
             self.results["msg"] = "Failed to reset ports"
             return False
 
-        for i, (src, dst) in enumerate(self.params.flows):
-            L2 = trex_api.Ether(
-                    src=str(src["mac_addr"]),
-                    dst=str(dst["mac_addr"]))
-            L3 = trex_api.IP(
-                    src=str(src["ip_addr"]),
-                    dst=str(dst["ip_addr"]))
-            L4 = trex_api.UDP()
-            base_pkt = L2/L3/L4
-
-            pad = max(0, self.params.msg_size - len(base_pkt)) * 'x'
-            packet = base_pkt/pad
+        module = importlib.import_module('.'.join(["lnst",
"External", "TRex", self.params.module]))
+        stream_generator = module.register()
 
-            trex_packet = trex_api.STLPktBuilder(pkt=packet)
+        for i, (src, dst) in enumerate(self.params.flows):
+            port = self.params.ports[i]
+            modkwargs = {}
+            modkwargs["port_id"] = port
+            modkwargs["msg_size"] = self.params.msg_size
+            modkwargs["src_ip"] = src["ip_addr"]
+            modkwargs["dst_ip"] = dst["ip_addr"]
+            modkwargs["src_mac"] = src["mac_addr"]
+            modkwargs["dst_mac"] = dst["mac_addr"]
 
-            trex_stream = trex_api.STLStream(
-                    packet=trex_packet,
-                    mode=trex_api.STLTXCont(percentage=100))
+            trex_streams = stream_generator.get_streams(direction=(port%2), **modkwargs)
 
-            port = self.params.ports[i]
-            client.add_streams(trex_stream, ports=[port])
+            client.add_streams(trex_streams, ports=[port])
 
         client.set_port_attr(ports=self.params.ports, promiscuous=True)
 
-
         measurements = []
 
         client.start(ports=self.params.ports)
diff --git a/lnst/External/TRex/UDPSimple.py b/lnst/External/TRex/UDPSimple.py
new file mode 100644
index 0000000..dfa89de
--- /dev/null
+++ b/lnst/External/TRex/UDPSimple.py
@@ -0,0 +1,38 @@
+from trex_stl_lib.api import *
+
+
+class UDPSimple(object):
+    """
+    Generate a simple continuous UDP stream
+    Port MAC and IP addresses are used
+    Extra arguments in kwargs:
+    msg_size: the size of the packet to use (default 64)
+    port_id:  The port the stream will be added to
+    """
+
+    def create_stream (self, **kwargs):
+        # Use port's configured mac and ip addresses
+        L2 = Ether()
+        L3 = IP()
+        L4 = UDP()
+
+        size = kwargs.get("msg_size", 64)
+
+        base_pkt = L2/L3/L4
+
+        pad = max(0, size - len(base_pkt)) * 'x'
+        packet = base_pkt/pad
+        trex_packet = STLPktBuilder(pkt=packet)
+
+        return STLStream(
+                    packet=trex_packet,
+                    mode=STLTXCont(percentage=100))
+
+    def get_streams (self, direction = 0, **kwargs):
+        # create 1 stream 
+        return [ self.create_stream(**kwargs) ]
+
+# dynamic load - used for trex console or simulator
+def register():
+    return UDPSimple()
+
-- 
2.26.2