Log network activity using tcpdump for nitb interface

Change-Id: I4c5d0e2d9857160f905e743517e744f1a06368af

src/osmo_gsm_tester/osmo_nitb.py

@@ -22,7 +22,7 @@ import random
 import re
 import socket
 
-from . import log, util, config, template, process, osmo_ctrl
+from . import log, util, config, template, process, osmo_ctrl, pcaprecorder
 
 class OsmoNitb(log.Origin):
     suite_run = None
@@ -51,6 +51,10 @@ class OsmoNitb(log.Origin):
         if not os.path.isdir(lib):
             raise RuntimeError('No lib/ in %r' % inst)
 
+        iface = util.ip_to_iface(self.addr())
+        pcaprecorder.PcapRecorder(self.suite_run, self.run_dir.new_dir('pcap'),
+                                  iface, self.addr())
+
         env = { 'LD_LIBRARY_PATH': util.prepend_library_path(lib) }
 
         self.dbg(run_dir=self.run_dir, binary=binary, env=env)

src/osmo_gsm_tester/pcaprecorder.py

@@ -0,0 +1,59 @@
+# osmo_gsm_tester: specifics for running an osmo-nitb
+#
+# Copyright (C) 2016-2017 by sysmocom - s.f.m.c. GmbH
+#
+# Author: Pau Espin Pedrol <pespin@sysmocom.de>
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU Affero General Public License as
+# published by the Free Software Foundation, either version 3 of the
+# License, or (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU Affero General Public License for more details.
+#
+# You should have received a copy of the GNU Affero General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+import os
+import random
+import re
+import socket
+
+from . import log, util, config, template, process, osmo_ctrl
+
+class PcapRecorder(log.Origin):
+
+    def __init__(self, suite_run, run_dir, iface=None, addr=None):
+        self.suite_run = suite_run
+        self.run_dir = run_dir
+        self.iface = iface
+        if not self.iface:
+            self.iface = "any"
+        self.addr = addr
+        self.set_log_category(log.C_RUN)
+        self.set_name('pcap-recorder_%s' % self.iface)
+        self.start()
+
+    def start(self):
+        self.log('Recording pcap', self.run_dir, self.gen_filter())
+        dumpfile = os.path.join(os.path.abspath(self.run_dir), self.name() + ".pcap")
+        self.process = process.Process(self.name(), self.run_dir,
+                                       ('tcpdump', '-n',
+                                       '-i', self.iface,
+                                       '-w', dumpfile,
+                                       self.gen_filter())
+                                       )
+        self.suite_run.remember_to_stop(self.process)
+        self.process.launch()
+
+    def gen_filter(self):
+        filter = ""
+        if self.addr:
+            filter += 'host ' + self.addr
+        return filter
+
+    def running(self):
+        return not self.process.terminated()

src/osmo_gsm_tester/util.py

@@ -30,7 +30,7 @@ import importlib.util
 import fcntl
 import tty
 import readline
-
+import subprocess
 
 def prepend_library_path(path):
     lp = os.getenv('LD_LIBRARY_PATH')
@@ -38,6 +38,17 @@ def prepend_library_path(path):
         return path
     return path + ':' + lp
 
+def ip_to_iface(ip):
+    try:
+        for iface in os.listdir('/sys/class/net'):
+            proc = subprocess.Popen(['ip', 'addr', 'show', 'dev', iface], stdout=subprocess.PIPE, universal_newlines=True)
+            for line in proc.stdout.readlines():
+                if 'inet' in line and ' ' + ip + '/' in line:
+                    return iface
+    except Exception as e:
+        pass
+    return None
+
 class listdict:
     'a dict of lists { "a": [1, 2, 3],  "b": [1, 2] }'
     def __getattr__(ld, name):