352 lines
13 KiB
Python
352 lines
13 KiB
Python
"""
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Chapter 10 (IRIG106) protocol dissector and packet handling
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"""
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import struct
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from typing import Dict, List, Optional, Any, Tuple
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from dataclasses import dataclass, field
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from abc import ABC, abstractmethod
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try:
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from scapy.all import Packet, Raw, IP, UDP
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except ImportError:
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print("Error: scapy library required. Install with: pip install scapy")
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import sys
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sys.exit(1)
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try:
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import numpy as np
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except ImportError:
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print("Error: numpy library required. Install with: pip install numpy")
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import sys
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sys.exit(1)
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from .base import ProtocolDissector, DissectionResult, ProtocolType
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class Chapter10Dissector(ProtocolDissector):
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"""Chapter 10 packet dissector based on IRIG 106-17 specification"""
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# Channel data types from Chapter 10 spec
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CH10_DATA_TYPES = {
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0x08: "PCM Format 1",
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0x09: "Time Format 1",
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0x11: "1553 Format 1",
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0x19: "Image Format 0",
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0x21: "UART Format 0",
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0x30: "1394 Format 1",
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0x38: "Parallel Format 1",
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0x40: "Ethernet Format 0",
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0x48: "TSPI/CTS Format 1",
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0x50: "Controller Area Network Bus",
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0x58: "Fibre Channel Format 1",
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0x60: "IRIG 106 Format 1",
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0x68: "Video Format 0",
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0x69: "Video Format 1",
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0x6A: "Video Format 2",
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0x70: "Message Format 0",
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0x78: "ARINC 429 Format 0",
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0x04: "PCM Format 0",
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0x72: "Analog Format 2",
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0x73: "Analog Format 3",
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0x74: "Analog Format 4",
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0x75: "Analog Format 5",
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0x76: "Analog Format 6",
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0x77: "Analog Format 7",
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0x78: "Analog Format 8",
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0xB4: "User Defined Format"
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}
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def __init__(self):
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self.sync_pattern = 0xEB25 # Chapter 10 sync pattern
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def can_dissect(self, packet: Packet) -> bool:
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"""Check if packet contains Chapter 10 data"""
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if not packet.haslayer(Raw):
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return False
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raw_data = bytes(packet[Raw])
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if len(raw_data) < 24: # Minimum Ch10 header size
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return False
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return self._find_chapter10_offset(raw_data) is not None
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def get_protocol_type(self) -> ProtocolType:
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return ProtocolType.CHAPTER10
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def dissect(self, packet: Packet) -> Optional[DissectionResult]:
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"""Dissect Chapter 10 packet (handles embedded formats)"""
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if not packet.haslayer(Raw):
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return None
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raw_data = bytes(packet[Raw])
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if len(raw_data) < 24: # Minimum Ch10 header size
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return None
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# Search for Chapter 10 sync pattern in the payload
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ch10_offset = self._find_chapter10_offset(raw_data)
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if ch10_offset is None:
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return None
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try:
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# Parse Chapter 10 header starting at the found offset
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if ch10_offset + 24 > len(raw_data):
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return None
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header_data = raw_data[ch10_offset:ch10_offset + 24]
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header = self._parse_header(header_data)
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if header.get('sync_pattern') != self.sync_pattern:
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return None
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result = DissectionResult(
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protocol=ProtocolType.CHAPTER10,
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fields=header
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)
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# Add container information
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if ch10_offset > 0:
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result.fields['container_offset'] = ch10_offset
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result.fields['container_header'] = raw_data[:ch10_offset].hex()
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# Extract payload if present
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packet_length = header.get('packet_length', 0)
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payload_start = ch10_offset + 24
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if packet_length > 24 and payload_start + (packet_length - 24) <= len(raw_data):
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result.payload = raw_data[payload_start:payload_start + (packet_length - 24)]
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# Try to parse specific data formats
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data_type = header.get('data_type', 0)
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if data_type == 0x40: # Ethernet Format 0
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eth_data = self._parse_ethernet_fmt0(result.payload)
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if eth_data:
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result.fields.update(eth_data)
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return result
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except Exception as e:
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return DissectionResult(
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protocol=ProtocolType.CHAPTER10,
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fields={},
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errors=[f"Parsing error: {str(e)}"]
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)
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def _find_chapter10_offset(self, raw_data: bytes) -> Optional[int]:
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"""Find the offset of Chapter 10 sync pattern in raw data"""
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# Search for the sync pattern throughout the payload
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for offset in range(len(raw_data) - 1):
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if offset + 1 < len(raw_data):
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try:
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word = struct.unpack('<H', raw_data[offset:offset+2])[0]
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if word == self.sync_pattern:
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# Verify we have enough space for a full header
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if offset + 24 <= len(raw_data):
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return offset
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except struct.error:
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continue
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return None
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def _parse_header(self, header_data: bytes) -> Dict[str, Any]:
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"""Parse Chapter 10 header"""
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if len(header_data) < 24:
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raise ValueError(f"Header too short: {len(header_data)} bytes, need 24")
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try:
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sync_pattern = struct.unpack('<H', header_data[0:2])[0]
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channel_id = struct.unpack('<H', header_data[2:4])[0]
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packet_length = struct.unpack('<I', header_data[4:8])[0]
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data_length = struct.unpack('<I', header_data[8:12])[0]
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data_type = struct.unpack('<H', header_data[12:14])[0]
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flags = struct.unpack('<H', header_data[14:16])[0]
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# Time counter is 6 bytes - combine into single value
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time_bytes = header_data[16:22]
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time_counter = int.from_bytes(time_bytes, 'little')
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sequence_number = struct.unpack('<H', header_data[22:24])[0]
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return {
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'sync_pattern': sync_pattern,
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'channel_id': channel_id,
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'packet_length': packet_length,
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'data_length': data_length,
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'data_type': data_type,
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'relative_time_counter': time_counter,
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'packet_flags': flags,
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'sequence_number': sequence_number,
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'data_type_name': self.CH10_DATA_TYPES.get(data_type, f"Unknown (0x{data_type:02x})")
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}
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except struct.error as e:
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raise ValueError(f"Struct unpack error: {str(e)}")
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def _parse_ethernet_fmt0(self, payload: bytes) -> Optional[Dict[str, Any]]:
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"""Parse Ethernet Format 0 data"""
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if len(payload) < 12:
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return None
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try:
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# Parse intra-packet header and frame word
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iph, ts, frame_word = struct.unpack('<III', payload[:12])
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frame_length = frame_word & 0x3FFF
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length_error = bool(frame_word & 0x8000)
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crc_error = bool(frame_word & 0x10000)
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content_type = (frame_word >> 28) & 0x3
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content_types = {0: "Full MAC frame", 1: "Payload only", 2: "Reserved", 3: "Reserved"}
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return {
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'ethernet_iph': iph,
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'ethernet_timestamp': ts,
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'ethernet_frame_length': frame_length,
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'ethernet_length_error': length_error,
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'ethernet_crc_error': crc_error,
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'ethernet_content_type': content_types.get(content_type, "Unknown")
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}
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except:
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return None
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class Chapter10Packet:
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"""Represents an IRIG106 Chapter 10 packet"""
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def __init__(self, packet, original_frame_num: Optional[int] = None):
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"""
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Initialize Chapter 10 packet from raw scapy packet
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Args:
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packet: Raw scapy packet
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original_frame_num: Original frame number in PCAP file
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"""
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self.raw_packet = packet
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self.original_frame_num: Optional[int] = original_frame_num
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# Extract basic packet info
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self.timestamp = float(packet.time)
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self.packet_size = len(packet)
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# Extract IP/UDP info if available
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if packet.haslayer(IP) and packet.haslayer(UDP):
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ip_layer = packet[IP]
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udp_layer = packet[UDP]
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self.src_ip = ip_layer.src
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self.dst_ip = ip_layer.dst
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self.src_port = udp_layer.sport
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self.dst_port = udp_layer.dport
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self.payload = bytes(udp_layer.payload)
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else:
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self.src_ip = ""
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self.dst_ip = ""
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self.src_port = 0
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self.dst_port = 0
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self.payload = bytes()
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# Parse Chapter 10 header
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self.ch10_header = self._parse_ch10_header()
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def _parse_ch10_header(self) -> Optional[Dict]:
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"""Parse Chapter 10 header from payload"""
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if len(self.payload) < 28: # Minimum payload size (4-byte prefix + 24-byte Ch10 header)
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return None
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try:
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# Look for Ch10 sync pattern in first several bytes
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ch10_offset = None
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for offset in range(min(8, len(self.payload) - 24)):
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sync_pattern = struct.unpack('<H', self.payload[offset:offset+2])[0]
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if sync_pattern == 0xEB25: # Ch10 sync pattern
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ch10_offset = offset
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break
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if ch10_offset is None:
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return None
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# Parse Chapter 10 header starting at found offset
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base = ch10_offset
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sync_pattern = struct.unpack('<H', self.payload[base:base+2])[0]
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channel_id = struct.unpack('<H', self.payload[base+2:base+4])[0]
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packet_length = struct.unpack('<I', self.payload[base+4:base+8])[0]
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data_length = struct.unpack('<I', self.payload[base+8:base+12])[0]
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header_version = self.payload[base+12]
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sequence_number = self.payload[base+13]
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packet_flags = self.payload[base+14]
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data_type = self.payload[base+15]
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rtc_low = struct.unpack('<I', self.payload[base+16:base+20])[0]
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rtc_high = struct.unpack('<H', self.payload[base+20:base+22])[0]
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checksum = struct.unpack('<H', self.payload[base+22:base+24])[0]
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# Store the offset for reference
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self.ch10_offset = ch10_offset
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return {
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'sync_pattern': f'0x{sync_pattern:04X}',
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'channel_id': channel_id,
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'packet_length': packet_length,
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'data_length': data_length,
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'header_version': header_version,
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'sequence_number': sequence_number,
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'packet_flags': f'0x{packet_flags:02X}',
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'data_type': f'0x{data_type:02X}',
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'rtc_low': rtc_low,
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'rtc_high': rtc_high,
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'checksum': f'0x{checksum:04X}',
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'rtc_timestamp': (rtc_high << 32) | rtc_low,
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'ch10_offset': ch10_offset
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}
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except (struct.error, IndexError):
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return None
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def get_data_payload(self) -> Optional[bytes]:
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"""Extract the data payload from the Chapter 10 packet"""
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if not self.ch10_header:
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return None
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# Data starts after the 24-byte Chapter 10 header
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data_start = self.ch10_offset + 24
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data_length = self.ch10_header['data_length']
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if data_start + data_length > len(self.payload):
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return None
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return self.payload[data_start:data_start + data_length]
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# Data decoders and related classes would go here, extracted from chapter10_packet.py
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# For brevity, I'll include the key classes but the full implementation would include
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# all the decoder classes (AnalogDecoder, PCMDecoder, etc.)
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@dataclass
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class DecodedData:
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"""Base class for decoded Chapter 10 data"""
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def __init__(self, data_type: str, channel_data: Dict[str, np.ndarray],
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timestamps: Optional[np.ndarray] = None, metadata: Optional[Dict] = None):
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self.data_type = data_type
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self.channel_data = channel_data
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self.timestamps = timestamps
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self.metadata = metadata or {}
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def get_channels(self) -> List[str]:
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"""Get list of available channels"""
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return list(self.channel_data.keys())
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def get_channel_data(self, channel: str) -> Optional[np.ndarray]:
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"""Get data for a specific channel"""
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return self.channel_data.get(channel)
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class DataDecoder(ABC):
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"""Abstract base class for Chapter 10 data decoders"""
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def __init__(self, tmats_scaling_dict: Optional[Dict] = None):
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self.tmats_scaling_dict = tmats_scaling_dict or {}
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@abstractmethod
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def decode(self, data_payload: bytes, ch10_header: Dict) -> Optional[DecodedData]:
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"""Decode the data payload"""
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pass |