79 lines
3.3 KiB
Python
79 lines
3.3 KiB
Python
#!/usr/bin/env python3
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# Copyright (c) Nordic Semiconductor ASA
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# All rights reserved.
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#
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# Redistribution and use in source and binary forms, with or without modification,
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# are permitted provided that the following conditions are met:
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#
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# 1. Redistributions of source code must retain the above copyright notice, this
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# list of conditions and the following disclaimer.
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#
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# 2. Redistributions in binary form, except as embedded into a Nordic
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# Semiconductor ASA integrated circuit in a product or a software update for
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# such product, must reproduce the above copyright notice, this list of
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# conditions and the following disclaimer in the documentation and/or other
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# materials provided with the distribution.
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#
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# 3. Neither the name of Nordic Semiconductor ASA nor the names of its
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# contributors may be used to endorse or promote products derived from this
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# software without specific prior written permission.
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#
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# 4. This software, with or without modification, must only be used with a
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# Nordic Semiconductor ASA integrated circuit.
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#
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# 5. Any software provided in binary form under this license must not be reverse
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# engineered, decompiled, modified and/or disassembled.
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#
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# THIS SOFTWARE IS PROVIDED BY NORDIC SEMICONDUCTOR ASA "AS IS" AND ANY EXPRESS
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# OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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# OF MERCHANTABILITY, NONINFRINGEMENT, AND FITNESS FOR A PARTICULAR PURPOSE ARE
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# DISCLAIMED. IN NO EVENT SHALL NORDIC SEMICONDUCTOR ASA OR CONTRIBUTORS BE
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# LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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# CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE
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# GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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# HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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# LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
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# OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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import struct
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# See:
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# - https://github.com/pcapng/pcapng
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# - https://www.tcpdump.org/linktypes/LINKTYPE_NORDIC_BLE.html
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PACKET_HEADER = struct.Struct("<LLLL")
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GLOBAL_HEADER = struct.pack("<LHHIILL",
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0xa1b2c3d4, # PCAP magic number
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2, # PCAP major version
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4, # PCAP minor version
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0, # Reserved
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0, # Reserved
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0x0000ffff, # Max length of capture frame
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272) # Nordic BLE link type
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def get_global_header():
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"""Get the PCAP global header."""
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return GLOBAL_HEADER
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def create_packet(packet: bytes, timestamp_seconds: float):
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"""Create a PCAP packet.
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Args:
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packet (bytes): Packet in the Nordic BLE packet format.
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timestamp_seconds (float): a relative timestamp in seconds.
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Returns:
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bytes: a PCAP formatted packet.
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"""
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timestamp_floor = int(timestamp_seconds)
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timestamp_offset_us = int((timestamp_seconds - timestamp_floor) * 1_000_000)
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return struct.pack("<LLLL",
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timestamp_floor,
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timestamp_offset_us,
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len(packet),
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len(packet)) + packet
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