From 1f097564f377cbc25884d6c6760dc4cb9414e9f9 Mon Sep 17 00:00:00 2001
From: George Hughey <ghughey@umd.edu>
Date: Sat, 23 Nov 2019 17:07:02 +0000
Subject: [PATCH] Added trace action

---
 actions/trace.py | 80 ++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 80 insertions(+)
 create mode 100644 actions/trace.py

diff --git a/actions/trace.py b/actions/trace.py
new file mode 100644
index 0000000..3d7af87
--- /dev/null
+++ b/actions/trace.py
@@ -0,0 +1,80 @@
+import socket
+import time
+
+from scapy.config import conf
+
+from actions.action import Action
+import actions.utils
+
+
+class TraceAction(Action):
+    """
+    The Trace Action is used to TTL probe/traceroute a censor. When the action fires,
+    it sends the captured packet with increasing ttls within a certain range
+
+    TraceAction is an experimental action that is never used
+    in actual evolution
+    """
+    def __init__(self, start_ttl=1, end_ttl=64, environment_id=None):
+        Action.__init__(self, "trace", "out")
+        self.terminal = True
+        self.branching = False
+        self.start_ttl = start_ttl
+        self.end_ttl = end_ttl
+        # Since running this action might take enough time that additional packets
+        # get generated, only allow this action to run once
+        self.ran = False
+        # Define a socket
+        self.socket = conf.L3socket(iface=actions.utils.get_interface())
+
+    def run(self, packet, logger):
+        """
+        The trace action sends the captured packet repeatedly with increasing ttl probes
+        defined between the range of start_ttl to end_ttl. This is an experimental action,
+        and is not used for training.
+        """
+        logger.debug("  - Starting Trace action")
+
+        if not packet.haslayer("IP"):
+            logger.debug("  - Could not identify IP header to perform ttl trace")
+            return packet, None
+
+        if self.ran:
+            logger.debug("  - trace action already ran. Dropping given traffic. To reset this action, restart the engine.")
+            return None, None
+
+        self.ran = True
+        for ttl in range(self.start_ttl, self.end_ttl):
+            logger.debug("  - ttl=%d" % ttl)
+            packet.set("IP", "ttl", ttl)
+            logger.debug("Sending packet %s", str(packet))
+            self.socket.send(packet.packet)
+            time.sleep(1)
+
+        return None, None
+
+    def __str__(self):
+        """
+        Returns a string representation.
+        """
+        s = Action.__str__(self)
+        s += "{%d:%d}" % (self.start_ttl, self.end_ttl)
+        return s
+
+    def parse(self, string, logger):
+        """
+        Parses a string representation for this object.
+        """
+        try:
+            if string:
+                self.start_ttl, self.end_ttl = string.split(":")
+                self.start_ttl = int(self.start_ttl)
+                self.end_ttl = int(self.end_ttl)
+                if self.start_ttl > self.end_ttl:
+                    logger.error("Cannot use a trace with a start ttl greater than end_ttl (%d > %d)" % (self.start_ttl, self.end_ttl))
+                    return False
+        except ValueError:
+            logger.exception("Cannot parse ttls from given data %s" % string)
+            return False
+
+        return True