Fixup of PR #423 (IEEE80211 DELBA frame) (#516)

* Implement decoding of DELBA Mgmt Action (Delete Block Ack).

dpkt/ieee80211.py

@@ -115,6 +115,7 @@
 # Block ack category action codes
 BLOCK_ACK_CODE_REQUEST = 0
 BLOCK_ACK_CODE_RESPONSE = 1
+BLOCK_ACK_CODE_DELBA = 2
 
 
 class IEEE80211(dpkt.Packet):
@@ -132,6 +133,10 @@ class IEEE80211(dpkt.Packet):
         ('duration', 'H', 0)
     )
 
+    # The standard really defines the entire MAC protocol as little-endian on the wire,
+    # however there is broken logic in the rest of the module preventing this from working right now
+    #__byte_order__ = '<'
+
     @property
     def version(self):
         return (self.framectl & _VERSION_MASK) >> _VERSION_SHIFT
@@ -517,6 +522,7 @@ def unpack(self, buf):
                 BLOCK_ACK: {
                     BLOCK_ACK_CODE_REQUEST: ('block_ack_request', IEEE80211.BlockAckActionRequest),
                     BLOCK_ACK_CODE_RESPONSE: ('block_ack_response', IEEE80211.BlockAckActionResponse),
+                    BLOCK_ACK_CODE_DELBA: ('block_ack_delba', IEEE80211.BlockAckActionDelba),
                 },
             }
 
@@ -546,6 +552,14 @@ class BlockAckActionResponse(dpkt.Packet):
             ('timeout', 'H', 0),
         )
 
+    class BlockAckActionDelba(dpkt.Packet):
+        __byte_order__ = '<'
+        __hdr__ = (
+            ('delba_param_set', 'H', 0),
+            ('reason_code', 'H', 0),
+            #('gcr_group_addr', '8s', '\x00' * 8), # Standard says it must be there, but it isn't?
+        )
+
     class Data(dpkt.Packet):
         __hdr__ = (
             ('dst', '6s', '\x00' * 6),
@@ -781,6 +795,16 @@ def test_action_block_ack_response():
     parameters = struct.unpack('<H', b'\x10\x02')[0]
     assert ieee.action.block_ack_response.parameters == parameters
 
+def test_action_block_ack_delete():
+    s = b'\xd0\x00\x2c\x00\x00\xc1\x41\x06\x13\x0d\x6c\xb2\xae\xae\xde\x80\x6c\xb2\xae\xae\xde\x80\xa0\x52\x03\x02\x00\x08\x01\x00\x74\x5d\x0a\xc6'
+    ieee = IEEE80211(s, fcs=True)
+    assert ieee.type == MGMT_TYPE
+    assert ieee.subtype == M_ACTION
+    assert ieee.action.category == BLOCK_ACK
+    assert ieee.action.code == BLOCK_ACK_CODE_DELBA
+    assert ieee.action.block_ack_delba.delba_param_set == 0x0800
+    assert ieee.action.block_ack_delba.reason_code == 1
+
 if __name__ == '__main__':
     # Runs all the test associated with this class/file
     test_802211_ack()
@@ -792,4 +816,5 @@ def test_action_block_ack_response():
     test_compressed_block_ack()
     test_action_block_ack_request()
     test_action_block_ack_response()
+    test_action_block_ack_delete()
     print('Tests Successful...')