DO NOT MERGE ANYWHERE

#!/usr/bin/env python

"""

This script extracts btsnooz content from bugreports and generates

a valid btsnoop log file which can be viewed using standard tools

like Wireshark.

btsnooz is a custom format designed to be included in bugreports.

It can be described as:

base64 {

  file_header

  deflate {

    repeated {

      record_header

      record_data

    }

  }

}

where the file_header and record_header are modified versions of

the btsnoop headers.

"""

import base64

import struct

import sys

import zlib

# Enumeration of the values the 'type' field can take in a btsnooz

# header. These values come from the Bluetooth stack's internal

# representation of packet types.

TYPE_IN_EVT = 0x10

TYPE_IN_ACL = 0x11

TYPE_IN_SCO = 0x12

TYPE_OUT_CMD = 0x20

TYPE_OUT_ACL = 0x21

TYPE_OUT_SCO = 0x22

def type_to_direction(type):

  """

  Returns the inbound/outbound direction of a packet given its type.

  0 = sent packet

  1 = received packet

  """

  if type in [TYPE_IN_EVT, TYPE_IN_ACL, TYPE_IN_SCO]:

    return 1

  return 0

def type_to_hci(type):

  """

  Returns the HCI type of a packet given its btsnooz type.

  """

  if type == TYPE_OUT_CMD:

    return '\x01'

  if type == TYPE_IN_ACL or type == TYPE_OUT_ACL:

    return '\x02'

  if type == TYPE_IN_SCO or type == TYPE_OUT_SCO:

    return '\x03'

  if type == TYPE_IN_EVT:

    return '\x04'

def decode_snooz(snooz):

  """

  Decodes all known versions of a btsnooz file into a btsnoop file.

  """

  version, last_timestamp_ms = struct.unpack_from('=bQ', snooz)

  if version != 1 and version != 2:

    sys.stderr.write('Unsupported btsnooz version: %s\n' % version)

    exit(1)

  # Oddly, the file header (9 bytes) is not compressed, but the rest is.

  decompressed = zlib.decompress(snooz[9:])

  sys.stdout.write('btsnoop\x00\x00\x00\x00\x01\x00\x00\x03\xea')

  if version == 1:

    decode_snooz_v1(decompressed, last_timestamp_ms)

  elif version == 2:

    decode_snooz_v2(decompressed, last_timestamp_ms)

def decode_snooz_v1(decompressed, last_timestamp_ms):

  """

  Decodes btsnooz v1 files into a btsnoop file.

  """

  # An unfortunate consequence of the file format design: we have to do a

  # pass of the entire file to determine the timestamp of the first packet.

  first_timestamp_ms = last_timestamp_ms + 0x00dcddb30f2f8000

  offset = 0

  while offset < len(decompressed):

    length, delta_time_ms, type = struct.unpack_from('=HIb', decompressed, offset)

    offset += 7 + length - 1

    first_timestamp_ms -= delta_time_ms

  # Second pass does the actual writing out to stdout.

  offset = 0

  while offset < len(decompressed):

    length, delta_time_ms, type = struct.unpack_from('=HIb', decompressed, offset)

    first_timestamp_ms += delta_time_ms

    offset += 7

    sys.stdout.write(struct.pack('>II', length, length))

    sys.stdout.write(struct.pack('>II', type_to_direction(type), 0))

    sys.stdout.write(struct.pack('>II', (first_timestamp_ms >> 32), (first_timestamp_ms & 0xFFFFFFFF)))

    sys.stdout.write(type_to_hci(type))

    sys.stdout.write(decompressed[offset : offset + length - 1])

    offset += length - 1

def decode_snooz_v2(decompressed, last_timestamp_ms):

  """

  Decodes btsnooz v2 files into a btsnoop file.

  """

  # An unfortunate consequence of the file format design: we have to do a

  # pass of the entire file to determine the timestamp of the first packet.

  first_timestamp_ms = last_timestamp_ms + 0x00dcddb30f2f8000

  offset = 0

  while offset < len(decompressed):

    length, packet_length, delta_time_ms, snooz_type = struct.unpack_from('=HHIb', decompressed, offset)

    offset += 9 + length - 1

    first_timestamp_ms -= delta_time_ms

  # Second pass does the actual writing out to stdout.

  offset = 0

  while offset < len(decompressed):

    length, packet_length, delta_time_ms, snooz_type = struct.unpack_from('=HHIb', decompressed, offset)

    first_timestamp_ms += delta_time_ms

    offset += 9

    sys.stdout.write(struct.pack('>II', packet_length, length))

    sys.stdout.write(struct.pack('>II', type_to_direction(snooz_type), 0))

    sys.stdout.write(struct.pack('>II', (first_timestamp_ms >> 32), (first_timestamp_ms & 0xFFFFFFFF)))

    sys.stdout.write(type_to_hci(snooz_type))

    sys.stdout.write(decompressed[offset : offset + length - 1])

    offset += length - 1

def main():

  if len(sys.argv) != 2:

    sys.stderr.write('Usage: %s <bugreport>\n' % sys.argv[0])

    exit(1)

  with open(sys.argv[1]) as f:

    while True:

      line = f.readline()

      if not line:

        break

      if line.startswith('--- BEGIN:BTSNOOP_LOG_SUMMARY'):

        decode_snooz(base64.standard_b64decode(f.readline()))

        sys.exit(0)

  sys.stderr.write('No btsnooz section found in bugreport.\n');

if __name__ == '__main__':

  main()