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#!/usr/bin/env python3
import random
import struct
import sys
import argparse
import usb.core
import usb.util
LOOPER_VID = 0x0483
LOOPER_PID = 0x572a
ENDPOINT_IN = 0x81
ENDPOINT_OUT = 0x01
COMMAND_SIZE = 0xfe
COMMAND_DATA = 0xff
def random_tag():
return random.randint(0, 1<<32 - 1)
def mass_storage_header(data_len, cdb_len, tag=None):
header = "USBC".encode('ascii')
if not tag:
tag = random_tag()
flags = 0x80
target = 0x00
header += struct.pack('<iiBBB', tag, data_len, flags, target, cdb_len)
return header
def command_header(command, data_len, flag1, flag2, tag=None):
cdb = bytes([0xcb, command, flag1, 0x00, flag2, 0x00, 0x00, 0x00, 0x00, 0x00])
header = mass_storage_header(data_len, len(cdb), tag) + cdb
header += bytes([0x00 for padding in range(31-len(header))])
return header
def ack_data(dev):
dev.read(ENDPOINT_IN, 32)
def get_size(dev):
header = command_header(COMMAND_SIZE, 5, 0x00, 0x01)
dev.write(ENDPOINT_OUT, header)
length = dev.read(ENDPOINT_IN, 100)
ack_data(dev)
if length[0] == 1:
return 0
return length[1] + (length[2] << 8) + (length[3] << 16) + (length[4] << 24)
def submit_data_len(dev, size, tag=None):
header = command_header(COMMAND_SIZE, 5, 0x00, 0x00, tag)
data_size = struct.pack('<bi', 0x00, size)
dev.write(ENDPOINT_OUT, header)
dev.write(ENDPOINT_OUT, data_size)
ack_data(dev)
def get_data(dev, nbytes):
header = command_header(COMMAND_DATA, nbytes, 0x01, 0x01)
dev.write(ENDPOINT_OUT, header)
buf = dev.read(ENDPOINT_IN, nbytes)
ack_data(dev)
return buf
def send_data(dev, data, tag=None):
header = command_header(COMMAND_DATA, len(data), 0x01, 0x00, tag)
dev.write(ENDPOINT_OUT, header)
dev.write(ENDPOINT_OUT, data)
ack_data(dev)
def write_wav_header(outfile, data_size):
header_size = 44
header = "RIFF".encode('ascii')
header += struct.pack('<i', data_size + header_size - 8)
header += "WAVE".encode('ascii')
header += "fmt ".encode('ascii')
fmt = 0x01 # PCM
nchan = 1
rate = 48000
fsize = 3
bps = rate * fsize
bits = 24
header += struct.pack('<ihhiihh', 16, fmt, nchan, rate, bps, fsize, bits)
header += "data".encode('ascii')
header += struct.pack('<i', data_size)
outfile.write(header)
def init_device():
dev = usb.core.find(idVendor=LOOPER_VID, idProduct=LOOPER_PID)
if not dev:
print("Device not found.")
sys.exit(1)
if dev.is_kernel_driver_active(0):
dev.detach_kernel_driver(0)
dev.set_configuration()
return dev
def receive_file(dev):
size = get_size(dev)
if size == 0:
print("No data available.")
sys.exit(0)
with open("/tmp/dump.wav", 'wb') as outfile:
write_wav_header(outfile, size)
print("Receiving ", end='', flush=True)
while size > 0:
bufsize = (size >= 65536) and 65536 or size
# data needs to be transferred in multiples of 1k blocks
padding = (1024 - (bufsize % 1024)) % 1024
buf = get_data(dev, bufsize + padding)
print('.', end='', flush=True),
outfile.write(buf[:bufsize])
size -= bufsize
print(" Done.")
def transmit_file(dev):
with open("/tmp/dump.wav", 'rb') as infile:
content = infile.read()
tag = random_tag()
# skip first 44 bytes for now; we assume valid file. TODO: validate
content = content[44:]
content_size = len(content)
print("Transmitting ", end='', flush=True)
while len(content) > 0:
buf = content[:65536]
padsize = (1024 - (len(buf) % 1024)) % 1024
buf += b'\x00' * padsize
send_data(dev, buf, tag)
print('.', end='', flush=True),
content = content[65536:]
submit_data_len(dev, content_size, tag)
print(" Done.")
def main():
argp = argparse.ArgumentParser()
argp.add_argument('action', choices=['rx', 'tx'])
args = argp.parse_args()
dev = init_device()
if args.action == 'rx':
receive_file(dev)
elif args.action == 'tx':
transmit_file(dev)
if __name__ == "__main__":
main()
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