From 87b46a622411362f441b62199972e71d85d7d2d6 Mon Sep 17 00:00:00 2001
From: Nico Schottelius <nico@nico-notebook.schottelius.org>
Date: Thu, 29 Oct 2020 18:49:20 +0100
Subject: [PATCH] [scanner] finish prototype

ping @poljakowski - it's your turn now
---
 cdist/scan.py | 138 +++++++++++++++++++++++++++++++++++++++++++++++---
 1 file changed, 131 insertions(+), 7 deletions(-)

diff --git a/cdist/scan.py b/cdist/scan.py
index fa1bf5de..e2100499 100644
--- a/cdist/scan.py
+++ b/cdist/scan.py
@@ -19,24 +19,148 @@
 #
 #
 
-from scapy.all import *
-from scapy.data import ETHER_TYPES
+#
+# Interface to be implemented:
+# - cdist scan --mode {scan, trigger, install, config}, --mode can be repeated
+#   scan: scan / listen for icmp6 replies
+#   trigger: send trigger to multicast
+#   config: configure newly detected hosts
+#   install: install newly detected hosts
+#
+# Scanner logic
+#  - save results to configdir:
+#     basedir = ~/.cdist/scan/<ipv6-address>
+#     last_seen = ~/.cdist/scan/<ipv6-address>/last_seen -- record unix time or similar
+#     last_configured = ~/.cdist/scan/<ipv6-address>/last_configured -- record unix time or similar
+#     last_installed = ~/.cdist/scan/<ipv6-address>/last_configured -- record unix time or similar
+#
+#
+#
+#
+# cdist scan --list
+#       Show all known hosts including last seen flag
+#
+# Logic for reconfiguration:
+#
+#  - record when configured last time
+#  - introduce a parameter --reconfigure-after that takes time argument
+#  - reconfigure if a) host alive and b) reconfigure-after time passed
+#
 
 
+from multiprocessing import Process
+import os
+
+# FIXME: fail gracefully if non existent - i.e. "scapy required for scanner - please install python3-scapy"
+from scapy.all import *
+
+# Datetime overwrites scapy.all.datetime - needs to be imported AFTER
+import datetime
+
+class Trigger(object):
+    """
+    Trigger an ICMPv6EchoReply from all hosts that are alive
+    """
+
+    def __init__(self, interfaces=None, verbose=False):
+        self.interfaces = interfaces
+        self.verbose = verbose
+
+        # Wait 5 seconds before triggering again - FIXME: add parameter
+        self.sleeptime = 5
+
+    def start(self):
+        self.processes = []
+        for interface in self.interfaces:
+            p = Process(target=self.run_interface, args=(interface,))
+            self.processes.append(p)
+            p.start()
+
+    def join(self):
+        for process in self.processes:
+            process.join()
+
+    def run_interface(self, interface):
+        while True:
+            self.trigger(interface)
+            time.sleep(self.sleeptime)
+
+    def trigger(self, interface):
+        packet = IPv6(dst=f"ff02::1%{interface}") / ICMPv6EchoRequest()
+        send(packet, verbose=self.verbose)
+
 class Scanner(object):
-    def recv_msg_cpu(self, pkg):
-#        print(pkg.__repr__())
+    """
+    Scan for replies of hosts, maintain the up-to-date database
+    """
+
+    def __init__(self, interfaces=None, outdir=None):
+        self.interfaces = interfaces
+
+        if outdir:
+            self.outdir = outdir
+        else:
+            self.outdir = "."
+
+    def handle_pkg(self, pkg):
         if ICMPv6EchoReply in pkg:
             host = pkg['IPv6'].src
             print(f"Host {host} is alive")
 
+            dir = os.path.join(self.outdir, host)
+            fname = os.path.join(dir, "last_seen")
+
+            now = datetime.datetime.now()
+
+            os.makedirs(dir, exist_ok=True)
+
+            # FIXME: maybe adjust the format so we can easily parse again
+            with open(fname, "w") as fd:
+                fd.write(f"{now}\n")
+
 
     def scan(self):
-        sniff(iface="wlan0",
+        sniff(iface=self.interfaces,
               filter="icmp6",
-              prn=self.recv_msg_cpu)
+              prn=self.handle_pkg)
 
 
 if __name__ == '__main__':
-    s = Scanner()
+    t = Trigger(interfaces=["wlan0"])
+    t.start()
+
+    # Scanner can listen on many interfaces at the same time
+    s = Scanner(interfaces=["wlan0"])
     s.scan()
+
+    # Join back the trigger processes
+    t.join()
+
+    # Test in my lan shows:
+    # [18:48] bridge:cdist% ls -1d fe80::*
+    # fe80::142d:f0a5:725b:1103
+    # fe80::20d:b9ff:fe49:ac11
+    # fe80::20d:b9ff:fe4c:547d
+    # fe80::219:d2ff:feb2:2e12
+    # fe80::21b:fcff:feee:f446
+    # fe80::21b:fcff:feee:f45c
+    # fe80::21b:fcff:feee:f4b1
+    # fe80::21b:fcff:feee:f4ba
+    # fe80::21b:fcff:feee:f4bc
+    # fe80::21b:fcff:feee:f4c1
+    # fe80::21d:72ff:fe86:46b
+    # fe80::42b0:34ff:fe6f:f6f0
+    # fe80::42b0:34ff:fe6f:f863
+    # fe80::42b0:34ff:fe6f:f9b2
+    # fe80::4a5d:60ff:fea1:e55f
+    # fe80::77a3:5e3f:82cc:f2e5
+    # fe80::9e93:4eff:fe6c:c1f4
+    # fe80::ba69:f4ff:fec5:6041
+    # fe80::ba69:f4ff:fec5:8db7
+    # fe80::bad8:12ff:fe65:313d
+    # fe80::bad8:12ff:fe65:d9b1
+    # fe80::ce2d:e0ff:fed4:2611
+    # fe80::ce32:e5ff:fe79:7ea7
+    # fe80::d66d:6dff:fe33:e00
+    # fe80::e2ff:f7ff:fe00:20e6
+    # fe80::f29f:c2ff:fe7c:275e