Start effort to consolidate snoop open scan

Scan and pass results as snoop answers.  They should
be like snoop answers, but with extra detail that will
be discarded.

confluent_server/confluent/discovery/slp.py

@@ -356,8 +356,18 @@ def snoop(handler):
     :return:
     """
     known_peers = set([])
+    peerbymacaddress = {}
     for scanned in scan(_slp_services):
-        print(repr(scanned))
+        for addr in scanned['addresses']:
+            ip = addr[0].partition('%')[0]  # discard scope if present
+            if ip not in neighutil.neightable:
+                continue
+            if addr in known_peers:
+                break
+            known_peers.add(addr)
+        else:
+            handler(scanned)
+    print(repr(scanned))
     net = socket.socket(socket.AF_INET6, socket.SOCK_DGRAM)
     net.setsockopt(socket.IPPROTO_IPV6, socket.IPV6_V6ONLY, 1)
     slpg = socket.inet_pton(socket.AF_INET6, 'ff01::123')
@@ -378,7 +388,7 @@ def snoop(handler):
     net4.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
     net.bind(('', 427))
     net4.bind(('', 427))
-    peerbymacaddress = {}
+
     while True:
         newmacs = set([])
         r, _, _ = select.select((net, net4), (), (), 60)