traffic: improve is_really_a_packet

This function will repeat on each packet.
Avoid exception for getattr, which is expensive for performance.

Signed-off-by: Joe Guo <joeg@catalyst.net.nz>
Reviewed-by: Andrew Bartlett <abartlet@samba.org>
Reviewed-by: Garming Sam <garming@catalyst.net.nz>

1 files changed, 4 insertions, 5 deletions

diff --git a/python/samba/emulate/traffic.py b/python/samba/emulate/traffic.py
index 08a0fa32278..503e1e4c5bf 100644
--- a/python/samba/emulate/traffic.py
+++ b/python/samba/emulate/traffic.py
@@ -273,13 +273,12 @@ class Packet(object):
             return False
 
         fn_name = 'packet_%s_%s' % (self.protocol, self.opcode)
-        try:
-            fn = getattr(traffic_packets, fn_name)
-            if fn is traffic_packets.null_packet:
-                return False
-        except AttributeError:
+        fn = getattr(traffic_packets, fn_name, None)
+        if not fn:
             print("missing packet %s" % fn_name, file=sys.stderr)
             return False
+        if fn is traffic_packets.null_packet:
+            return False
         return True