44 lines
1.2 KiB
Python
44 lines
1.2 KiB
Python
# 导入Netzob库
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from netzob.all import *
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# 定义以太网802.3协议的各个字段
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# 1. 以太网长度字段（16位）2字节
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eth_length = Field(bitarray('0000000000000000'), "eth.length")
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# 2. IEEE 802.2 LLC头部（固定3字节）
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eth_llc = Field(Raw(nbBytes=3), "eth.llc")
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# 3. 以太网载荷字段
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eth_payload = Field(Raw(), name="eth.payload")
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# 4. 填充字段（保证以太网最小帧长60字节）
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eth_padding = Field(Padding(
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[eth_length, eth_llc, eth_payload],
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data=Raw(nbBytes=1),
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modulo=8*60),
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"eth.padding"
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)
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# 5. 以太网CRC校验字段（32位）
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eth_crc_802_3 = Field(bitarray('00000000000000000000000000000000'), "eth.crc")
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# 设置CRC32校验规则
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eth_crc_802_3.domain = CRC32(
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[eth_length, eth_llc, eth_payload, eth_padding],
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dataType=Raw(nbBytes=4, unitSize=UnitSize.SIZE_32)
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)
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# 设置长度字段：计算LLC+载荷的总长度
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eth_length.domain = Size(
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[eth_llc, eth_payload],
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dataType=uint16(),
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factor=1./8
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)
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# 构建完整的以太网802.3协议符号
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symbol = Symbol(
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name="ethernet_802_3",
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fields=[eth_length, eth_llc, eth_payload, eth_padding, eth_crc_802_3]
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)
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# 打印协议结构
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print(symbol.str_structure()) |