openflow_input: add bsn_gentable extension and tests
See the documentation in openflow_input/bsn_gentable.
diff --git a/test_data/of13/bsn_gentable_desc_stats_request.data b/test_data/of13/bsn_gentable_desc_stats_request.data
new file mode 100644
index 0000000..977fe29
--- /dev/null
+++ b/test_data/of13/bsn_gentable_desc_stats_request.data
@@ -0,0 +1,12 @@
+-- binary
+04 12 # version, type
+00 18 # length
+12 34 56 78 # xid
+ff ff # stats_type
+00 00 # flags
+00 00 00 00 # pad
+00 5c 16 c7 # experimenter
+00 00 00 04 # subtype
+-- python
+ofp.message.bsn_gentable_desc_stats_request(
+ xid=0x12345678)