add "!forget-peer-sshhostkey <node>"

modules/ffpb.py

@@ -822,3 +822,52 @@ def ffpb_remoteexec(bot, trigger):
             target_alias,
             err.output
         ))
+
+@willie.module.commands('forget-peer-sshhostkey')
+def ffpb_clearsshhostkey(bot, trigger):
+    """Forget given node's SSH host key"""
+
+    target_name = trigger.group(2) or ''
+    if len(target_name.strip()) == 0:
+        bot.say('Lasst uns einfach mal ' + trigger.nick + ' löschen!')
+        bot.say('Tipp: !forget-peer-sshhostkey <peer>')
+        return
+
+    # identify requested node or bail out
+    node = ffpb_findnode_from_botparam(bot, target_name,
+                                       ensure_recent_alfreddata=False)
+    if node is None:
+        return
+
+    # check ACL
+    if not playitsafe(bot, trigger, via_channel=True, node=node):
+        return
+
+    # derive target from node's MAC
+    node_mac = node.get('mac')
+    target = mac2ipv6(node_mac, 'fdca:ffee:ff12:132:')
+    target_alias = node["hostname"]
+
+    # assemble command
+    cmd = [
+        'ssh-keygen',
+        '-f', '.ssh/known_hosts',
+        '-R',
+        target,
+    ]
+    try:
+        # call command
+        result = subprocess.check_output(
+            cmd,
+            stderr=subprocess.STDOUT,
+            shell=False,
+        )
+	bot.reply('Ich mache den Weg frei ... also den zu "' + target + '" per SSH zumindest.')
+
+    except subprocess.CalledProcessError as err:
+        bot.say('Fehler {0} bei remove-sshhostkey-of-peer({1}): {2}'.format(
+            err.returncode,
+            target_alias,
+            err.output
+        ))
+