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Description
Brief description
When PacketFields are nested on several stages,
Scapy races exponential performance issues.
Scapy version
2.6.1
Python version
3.8.6
Operating system
Windows
Additional environment information
No response
How to reproduce
The following .uts test demonstrates the issue:
% Packet field performance issue
############
############
+ Test utils
= Prepare a `check_exec_time()` function.
def check_exec_time(description, t0, tf, max):
print(f"{description}: {tf - t0:.3f} seconds")
assert tf - t0 <= max, f"{description!r} FAILED: {tf - t0:.3f} > {max:.3f}"
############
############
+ Test data
= Define the `F` final packet class.
class F(Packet):
fields_desc = [
ByteField(name="value", default=0),
]
def extract_padding(self, s):
return (b'', s)
= Define the `I` intermediate packet class.
class I(Packet):
NUMBER_OF_F_PER_I = 100
fields_desc = [
PacketField(name=f"f{i}", pkt_cls=F, default=F(value=i))
for i in range(NUMBER_OF_F_PER_I)
]
def extract_padding(self, s):
return (b'', s)
= Define the `M` main packet class.
class M(Packet):
NUMBER_OF_I_PER_M = 100
fields_desc = [
PacketField(name=f"i{i}", pkt_cls=I, default=I())
for i in range(NUMBER_OF_I_PER_M)
]
= Define `MAX_INSTANTIATION_TIME_EXPECTED`.
MAX_INSTANTIATION_TIME_EXPECTED = 1.0
= Define `MAX_SERIALIZATION_TIME_EXPECTED`.
MAX_SERIALIZATION_TIME_EXPECTED = 0.250
= Define `MAX_PARSING_TIME_EXPECTED`.
MAX_PARSING_TIME_EXPECTED = 0.250
############
############
+ Default instantiations
= Build a default instance of `F`.
t0 = time.time()
f = F()
tf = time.time()
check_exec_time("Default instantiation of `F`", t0, tf, MAX_INSTANTIATION_TIME_EXPECTED)
= Build a default instance of `F` again.
t0 = time.time()
f = F()
tf = time.time()
check_exec_time("Default instantiation of `F`", t0, tf, MAX_INSTANTIATION_TIME_EXPECTED)
= Build a default instance of `I`.
t0 = time.time()
i = I()
tf = time.time()
check_exec_time("Default instantiation of `I`", t0, tf, MAX_INSTANTIATION_TIME_EXPECTED)
= Build a default instance of `B` again.
t0 = time.time()
i = I()
tf = time.time()
check_exec_time("Default instantiation of `I`", t0, tf, MAX_INSTANTIATION_TIME_EXPECTED)
= Build a default instance of `M`.
t0 = time.time()
m = M()
tf = time.time()
check_exec_time("Default instantiation of `M`", t0, tf, MAX_INSTANTIATION_TIME_EXPECTED)
= Build a default instance of `M` again.
t0 = time.time()
m = M()
tf = time.time()
check_exec_time("Default instantiation of `M`", t0, tf, MAX_INSTANTIATION_TIME_EXPECTED)
############
############
+ Serialization
= Launch serialization from the latest instance of `M` created.
t0 = time.time()
buf = m.build()
tf = time.time()
check_exec_time("Serialization of `M`", t0, tf, MAX_SERIALIZATION_TIME_EXPECTED)
############
############
+ Parsing
= Parse the buffer serialized before with the latest instance of `M` created.
t0 = time.time()
m.dissect(buf)
tf = time.time()
check_exec_time("Parsing of `M`", t0, tf, MAX_PARSING_TIME_EXPECTED)
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Expected result
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