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IPFIX: improve bitwise operation on enterprise flag bit

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This commit is contained in:
Dominik Pataky 2022-12-03 09:33:24 +01:00
parent 2eb2283873
commit fe1d3df296
1 changed files with 6 additions and 3 deletions
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9
netflow/ipfix.py
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@ -953,11 +953,11 @@ def parse_fields(data: bytes, count: int) -> (list, int):
offset = 0
fields = [] # type: List[Union[TemplateField, TemplateFieldEnterprise]]
for ctr in range(count):
if data[offset] & 1 << 7 != 0: # enterprise flag set
if (data[offset] & (1 << 7)) != 0: # enterprise flag set. Bitwise AND checks bit only in the first byte/octet
pack = struct.unpack("!HHI", data[offset:offset + 8])
fields.append(
TemplateFieldEnterprise(
id=pack[0] & ~(1 << 15), # ID, clear enterprise flag bit
id=(pack[0] & ~(1 << 15)), # clear enterprise flag bit. Bitwise AND and INVERT work on two bytes
length=pack[1], # field length
enterprise_number=pack[2] # enterprise number
)
@ -966,7 +966,10 @@ def parse_fields(data: bytes, count: int) -> (list, int):
else:
pack = struct.unpack("!HH", data[offset:offset + 4])
fields.append(
TemplateField(id=pack[0], length=pack[1])
TemplateField(
id=pack[0],
length=pack[1]
)
)
offset += 4
return fields, offset