Add MiniNDN utility application for PCAP logging

Change-Id: I4f8ee5b6b970c7b74e3697af4a08b72d2169dc2a
diff --git a/minindn/apps/tshark.py b/minindn/apps/tshark.py
new file mode 100644
index 0000000..6ff52fb
--- /dev/null
+++ b/minindn/apps/tshark.py
@@ -0,0 +1,60 @@
+# -*- Mode:python; c-file-style:"gnu"; indent-tabs-mode:nil -*- */
+#
+# Copyright (C) 2015-2020, The University of Memphis,
+#                          Arizona Board of Regents,
+#                          Regents of the University of California.
+#
+# This file is part of Mini-NDN.
+# See AUTHORS.md for a complete list of Mini-NDN authors and contributors.
+#
+# Mini-NDN is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# Mini-NDN 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 General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with Mini-NDN, e.g., in COPYING.md file.
+# If not, see <http://www.gnu.org/licenses/>.
+
+from minindn.apps.application import Application
+from mininet.log import debug
+
+
+class Tshark(Application):
+    """
+    Logging utility to dump network traffic of a node to a PCAP file.
+
+    The app is based on the command line tool tshark and requires tshark to be installed on the system.
+    """
+
+    def __init__(self, node, logFolder="./", singleLogFile=False):
+        """
+        :param logFolder Folder, where PCAP files are stored.
+        :param singleLogFile Single PCAP file per node, or individual PCAP for each interface
+        """
+
+        Application.__init__(self, node)
+
+        self.logFolder = logFolder
+        self.singleLogFile = singleLogFile
+
+        # Create logfile folder in case it does not exist
+        node.cmd('mkdir -p {}'.format(self.logFolder))
+
+    def start(self):
+        # Start capturing traffic with Tshark.
+        debug("[{0}] Starting tshark logging\n".format(self.node.name))
+
+        if self.singleLogFile:
+            interfaces = ["-i " + intf for intf in self.node.intfNames()]
+            ndnDumpOutputFile = "{}/{}-interfaces.pcap".format(self.logFolder, self.node.name)
+            self.node.cmd("tshark {} -w {} -q &".format(" ".join(interfaces), ndnDumpOutputFile))
+        else:
+            for intf in self.node.intfNames():
+                ndnDumpOutputFile = "{}/{}.pcap".format(self.logFolder, intf)
+                self.node.cmd("tshark -i {} -w {} -q &".format(intf, ndnDumpOutputFile))