diff --git a/codi-app/xmodem/__init__.py b/codi-app/xmodem/__init__.py new file mode 100644 index 0000000..582d92d --- /dev/null +++ b/codi-app/xmodem/__init__.py @@ -0,0 +1,766 @@ +''' +=============================== + XMODEM file transfer protocol +=============================== + +.. $Id$ + +This is a literal implementation of XMODEM.TXT_, XMODEM1K.TXT_ and +XMODMCRC.TXT_, support for YMODEM and ZMODEM is pending. YMODEM should +be fairly easy to implement as it is a hack on top of the XMODEM +protocol using sequence bytes ``0x00`` for sending file names (and some +meta data). + +.. _XMODEM.TXT: doc/XMODEM.TXT +.. _XMODEM1K.TXT: doc/XMODEM1K.TXT +.. _XMODMCRC.TXT: doc/XMODMCRC.TXT + +Data flow example including error recovery +========================================== + +Here is a sample of the data flow, sending a 3-block message. +It includes the two most common line hits - a garbaged block, +and an ``ACK`` reply getting garbaged. ``CRC`` or ``CSUM`` represents +the checksum bytes. + +XMODEM 128 byte blocks +---------------------- + +:: + + SENDER RECEIVER + + <-- NAK + SOH 01 FE Data[128] CSUM --> + <-- ACK + SOH 02 FD Data[128] CSUM --> + <-- ACK + SOH 03 FC Data[128] CSUM --> + <-- ACK + SOH 04 FB Data[128] CSUM --> + <-- ACK + SOH 05 FA Data[100] CPMEOF[28] CSUM --> + <-- ACK + EOT --> + <-- ACK + +XMODEM-1k blocks, CRC mode +-------------------------- + +:: + + SENDER RECEIVER + + <-- C + STX 01 FE Data[1024] CRC CRC --> + <-- ACK + STX 02 FD Data[1024] CRC CRC --> + <-- ACK + STX 03 FC Data[1000] CPMEOF[24] CRC CRC --> + <-- ACK + EOT --> + <-- ACK + +Mixed 1024 and 128 byte Blocks +------------------------------ + +:: + + SENDER RECEIVER + + <-- C + STX 01 FE Data[1024] CRC CRC --> + <-- ACK + STX 02 FD Data[1024] CRC CRC --> + <-- ACK + SOH 03 FC Data[128] CRC CRC --> + <-- ACK + SOH 04 FB Data[100] CPMEOF[28] CRC CRC --> + <-- ACK + EOT --> + <-- ACK + +YMODEM Batch Transmission Session (1 file) +------------------------------------------ + +:: + + SENDER RECEIVER + <-- C (command:rb) + SOH 00 FF foo.c NUL[123] CRC CRC --> + <-- ACK + <-- C + SOH 01 FE Data[128] CRC CRC --> + <-- ACK + SOH 02 FC Data[128] CRC CRC --> + <-- ACK + SOH 03 FB Data[100] CPMEOF[28] CRC CRC --> + <-- ACK + EOT --> + <-- NAK + EOT --> + <-- ACK + <-- C + SOH 00 FF NUL[128] CRC CRC --> + <-- ACK + + +''' +from __future__ import division, print_function + +__author__ = 'Wijnand Modderman ' +__copyright__ = ['Copyright (c) 2010 Wijnand Modderman', + 'Copyright (c) 1981 Chuck Forsberg', + 'Copyright (c) 2016 Michael Tesch'] +__license__ = 'MIT' +__version__ = '0.4.5' + +import platform +import logging +import time +import sys +from functools import partial + +# Protocol bytes +NUL = b'\x00' +SOH = b'\x01' +STX = b'\x02' +EOT = b'\x04' +ACK = b'\x06' +DLE = b'\x10' +NAK = b'\x15' +CAN = b'\x18' +CRC = b'C' + + +class XMODEM(object): + ''' + XMODEM Protocol handler, expects two callables which encapsulate the read + and write operations on the underlying stream. + + Example functions for reading and writing to a serial line: + + >>> import serial + >>> from xmodem import XMODEM + >>> ser = serial.Serial('/dev/ttyUSB0', timeout=0) # or whatever you need + >>> def getc(size, timeout=1): + ... return ser.read(size) or None + ... + >>> def putc(data, timeout=1): + ... return ser.write(data) or None + ... + >>> modem = XMODEM(getc, putc) + + + :param getc: Function to retrieve bytes from a stream. The function takes + the number of bytes to read from the stream and a timeout in seconds as + parameters. It must return the bytes which were read, or ``None`` if a + timeout occured. + :type getc: callable + :param putc: Function to transmit bytes to a stream. The function takes the + bytes to be written and a timeout in seconds as parameters. It must + return the number of bytes written to the stream, or ``None`` in case of + a timeout. + :type putc: callable + :param mode: XMODEM protocol mode + :type mode: string + :param pad: Padding character to make the packets match the packet size + :type pad: char + + ''' + + # crctab calculated by Mark G. Mendel, Network Systems Corporation + crctable = [ + 0x0000, 0x1021, 0x2042, 0x3063, 0x4084, 0x50a5, 0x60c6, 0x70e7, + 0x8108, 0x9129, 0xa14a, 0xb16b, 0xc18c, 0xd1ad, 0xe1ce, 0xf1ef, + 0x1231, 0x0210, 0x3273, 0x2252, 0x52b5, 0x4294, 0x72f7, 0x62d6, + 0x9339, 0x8318, 0xb37b, 0xa35a, 0xd3bd, 0xc39c, 0xf3ff, 0xe3de, + 0x2462, 0x3443, 0x0420, 0x1401, 0x64e6, 0x74c7, 0x44a4, 0x5485, + 0xa56a, 0xb54b, 0x8528, 0x9509, 0xe5ee, 0xf5cf, 0xc5ac, 0xd58d, + 0x3653, 0x2672, 0x1611, 0x0630, 0x76d7, 0x66f6, 0x5695, 0x46b4, + 0xb75b, 0xa77a, 0x9719, 0x8738, 0xf7df, 0xe7fe, 0xd79d, 0xc7bc, + 0x48c4, 0x58e5, 0x6886, 0x78a7, 0x0840, 0x1861, 0x2802, 0x3823, + 0xc9cc, 0xd9ed, 0xe98e, 0xf9af, 0x8948, 0x9969, 0xa90a, 0xb92b, + 0x5af5, 0x4ad4, 0x7ab7, 0x6a96, 0x1a71, 0x0a50, 0x3a33, 0x2a12, + 0xdbfd, 0xcbdc, 0xfbbf, 0xeb9e, 0x9b79, 0x8b58, 0xbb3b, 0xab1a, + 0x6ca6, 0x7c87, 0x4ce4, 0x5cc5, 0x2c22, 0x3c03, 0x0c60, 0x1c41, + 0xedae, 0xfd8f, 0xcdec, 0xddcd, 0xad2a, 0xbd0b, 0x8d68, 0x9d49, + 0x7e97, 0x6eb6, 0x5ed5, 0x4ef4, 0x3e13, 0x2e32, 0x1e51, 0x0e70, + 0xff9f, 0xefbe, 0xdfdd, 0xcffc, 0xbf1b, 0xaf3a, 0x9f59, 0x8f78, + 0x9188, 0x81a9, 0xb1ca, 0xa1eb, 0xd10c, 0xc12d, 0xf14e, 0xe16f, + 0x1080, 0x00a1, 0x30c2, 0x20e3, 0x5004, 0x4025, 0x7046, 0x6067, + 0x83b9, 0x9398, 0xa3fb, 0xb3da, 0xc33d, 0xd31c, 0xe37f, 0xf35e, + 0x02b1, 0x1290, 0x22f3, 0x32d2, 0x4235, 0x5214, 0x6277, 0x7256, + 0xb5ea, 0xa5cb, 0x95a8, 0x8589, 0xf56e, 0xe54f, 0xd52c, 0xc50d, + 0x34e2, 0x24c3, 0x14a0, 0x0481, 0x7466, 0x6447, 0x5424, 0x4405, + 0xa7db, 0xb7fa, 0x8799, 0x97b8, 0xe75f, 0xf77e, 0xc71d, 0xd73c, + 0x26d3, 0x36f2, 0x0691, 0x16b0, 0x6657, 0x7676, 0x4615, 0x5634, + 0xd94c, 0xc96d, 0xf90e, 0xe92f, 0x99c8, 0x89e9, 0xb98a, 0xa9ab, + 0x5844, 0x4865, 0x7806, 0x6827, 0x18c0, 0x08e1, 0x3882, 0x28a3, + 0xcb7d, 0xdb5c, 0xeb3f, 0xfb1e, 0x8bf9, 0x9bd8, 0xabbb, 0xbb9a, + 0x4a75, 0x5a54, 0x6a37, 0x7a16, 0x0af1, 0x1ad0, 0x2ab3, 0x3a92, + 0xfd2e, 0xed0f, 0xdd6c, 0xcd4d, 0xbdaa, 0xad8b, 0x9de8, 0x8dc9, + 0x7c26, 0x6c07, 0x5c64, 0x4c45, 0x3ca2, 0x2c83, 0x1ce0, 0x0cc1, + 0xef1f, 0xff3e, 0xcf5d, 0xdf7c, 0xaf9b, 0xbfba, 0x8fd9, 0x9ff8, + 0x6e17, 0x7e36, 0x4e55, 0x5e74, 0x2e93, 0x3eb2, 0x0ed1, 0x1ef0, + ] + + def __init__(self, getc, putc, mode='xmodem', pad=b'\x1a'): + self.getc = getc + self.putc = putc + self.mode = mode + self.pad = pad + self.log = logging.getLogger('xmodem.XMODEM') + + def abort(self, count=2, timeout=60): + ''' + Send an abort sequence using CAN bytes. + + :param count: how many abort characters to send + :type count: int + :param timeout: timeout in seconds + :type timeout: int + ''' + for _ in range(count): + self.putc(CAN, timeout) + + def send(self, stream, retry=16, timeout=60, quiet=False, callback=None): + ''' + Send a stream via the XMODEM protocol. + + >>> stream = open('/etc/issue', 'rb') + >>> print(modem.send(stream)) + True + + Returns ``True`` upon successful transmission or ``False`` in case of + failure. + + :param stream: The stream object to send data from. + :type stream: stream (file, etc.) + :param retry: The maximum number of times to try to resend a failed + packet before failing. + :type retry: int + :param timeout: The number of seconds to wait for a response before + timing out. + :type timeout: int + :param quiet: If True, write transfer information to stderr. + :type quiet: bool + :param callback: Reference to a callback function that has the + following signature. This is useful for + getting status updates while a xmodem + transfer is underway. + Expected callback signature: + def callback(total_packets, success_count, error_count) + :type callback: callable + ''' + + # initialize protocol + try: + packet_size = dict( + xmodem = 128, + xmodem1k = 1024, + ymodem = 1024, + )[self.mode] + except KeyError: + raise ValueError("Invalid mode specified: {self.mode!r}" + .format(self=self)) + + self.log.debug('Begin start sequence, packet_size=%d', packet_size) + error_count = 0 + crc_mode = 0 + cancel = 0 + while True: + char = self.getc(1) + if char: + if char == NAK: + self.log.debug('standard checksum requested (NAK).') + crc_mode = 0 + break + elif char == CRC: + self.log.debug('16-bit CRC requested (CRC).') + crc_mode = 1 + break + elif char == CAN: + if not quiet: + print('received CAN', file=sys.stderr) + if cancel: + self.log.info('Transmission canceled: received 2xCAN ' + 'at start-sequence') + return False + else: + self.log.debug('cancellation at start sequence.') + cancel = 1 + else: + self.log.error('send error: expected NAK, CRC, or CAN; ' + 'got %r', char) + + error_count += 1 + if error_count > retry: + self.log.info('send error: error_count reached %d, ' + 'aborting.', retry) + self.abort(timeout=timeout) + return False + + # send data + error_count = 0 + success_count = 0 + total_packets = 0 + if self.mode == 'ymodem': + sequence = 0 + filenames = stream + else: + sequence = 1 + while True: + # build packet + if self.mode == 'ymodem' and success_count == 0: + # send packet sequence 0 containing: + # Filename Length [Modification-Date [Mode [Serial-Number]]] + # 'stream' is actually the filename + import os + if len(filenames): + filename = filenames.pop() + stream = open(filename, 'rb') + stat = os.stat(filename) + data = os.path.basename(filename).encode() + NUL + str(stat.st_size).encode() + self.log.debug('ymodem sending : "%s" len:%d', filename, stat.st_size) + else: + # empty file name packet terminates transmission + filename = '' + data = ''.encode() + stream = None + self.log.debug('ymodem done, sending empty header.') + if len(data) <= 128: + header_size = 128 + else: + header_size = 1024 + + header = self._make_send_header(header_size, sequence) + data = data.ljust(header_size, NUL) + checksum = self._make_send_checksum(crc_mode, data) + else: + # happens after sending ymodem empty filename + if not stream: + return True + # normal data packet + data = stream.read(packet_size) + if not data: + # end of stream + self.log.debug('send: at EOF') + break + total_packets += 1 + + header = self._make_send_header(packet_size, sequence) + data = data.ljust(packet_size, self.pad) + checksum = self._make_send_checksum(crc_mode, data) + + # emit packet & get ACK + while True: + self.log.debug('send: block %d', sequence) + self.putc(header + data + checksum) + char = self.getc(1, timeout) + if char == ACK: + success_count += 1 + if callable(callback): + callback(total_packets, success_count, error_count) + error_count = 0 + if self.mode == 'ymodem' and success_count == 1 and len(filename): + char = self.getc(1, timeout) + if char == DLE: # dunno why + char = self.getc(1, timeout) + if char == CRC: + break + self.log.error('send error: ymodem expected CRC; got %r for block %d', + char, sequence) + else: + break + + self.log.error('send error: expected ACK; got %r for block %d', + char, sequence) + error_count += 1 + if callable(callback): + callback(total_packets, success_count, error_count) + if error_count > retry: + # excessive amounts of retransmissions requested, + # abort transfer + self.log.error('send error: NAK received %d times, ' + 'aborting.', error_count) + self.abort(timeout=timeout) + return False + + # keep track of sequence + sequence = (sequence + 1) % 0x100 + + # emit EOT and get corresponding ACK + while True: + self.log.debug('sending EOT, awaiting ACK') + # end of transmission + self.putc(EOT) + + # An ACK should be returned + char = self.getc(1, timeout) + if char == ACK: + break + else: + self.log.error('send error: expected ACK; got %r', char) + error_count += 1 + if error_count > retry: + self.log.warn('EOT was not ACKd, aborting transfer') + self.abort(timeout=timeout) + return False + + self.log.info('Transmission successful (ACK received).') + if self.mode == 'ymodem': + # YMODEM - recursively send next file + # or empty filename header to end the xfer batch. + stream.close() + return self.send(filenames, retry, timeout, quiet, callback) + return True + + def _make_send_header(self, packet_size, sequence): + assert packet_size in (128, 1024), packet_size + _bytes = [] + if packet_size == 128: + _bytes.append(ord(SOH)) + elif packet_size == 1024: + _bytes.append(ord(STX)) + _bytes.extend([sequence, 0xff - sequence]) + return bytearray(_bytes) + + def _make_send_checksum(self, crc_mode, data): + _bytes = [] + if crc_mode: + crc = self.calc_crc(data) + _bytes.extend([crc >> 8, crc & 0xff]) + else: + crc = self.calc_checksum(data) + _bytes.append(crc) + return bytearray(_bytes) + + def recv(self, stream, crc_mode=1, retry=16, timeout=60, delay=1, quiet=0): + ''' + Receive a stream via the XMODEM protocol. + + >>> stream = open('/etc/issue', 'wb') + >>> print(modem.recv(stream)) + 2342 + + Returns the number of bytes received on success or ``None`` in case of + failure. + + :param stream: The stream object to write data to. + :type stream: stream (file, etc.) + :param crc_mode: XMODEM CRC mode + :type crc_mode: int + :param retry: The maximum number of times to try to resend a failed + packet before failing. + :type retry: int + :param timeout: The number of seconds to wait for a response before + timing out. + :type timeout: int + :param delay: The number of seconds to wait between resend attempts + :type delay: int + :param quiet: If ``True``, write transfer information to stderr. + :type quiet: bool + + ''' + + # initiate protocol + error_count = 0 + char = 0 + cancel = 0 + while True: + # first try CRC mode, if this fails, + # fall back to checksum mode + if error_count >= retry: + self.log.info('error_count reached %d, aborting.', retry) + self.abort(timeout=timeout) + return None + elif crc_mode and error_count < (retry // 2): + if not self.putc(CRC): + self.log.debug('recv error: putc failed, ' + 'sleeping for %d', delay) + time.sleep(delay) + error_count += 1 + else: + crc_mode = 0 + if not self.putc(NAK): + self.log.debug('recv error: putc failed, ' + 'sleeping for %d', delay) + time.sleep(delay) + error_count += 1 + + char = self.getc(1, timeout) + if char is None: + self.log.warn('recv error: getc timeout in start sequence') + error_count += 1 + continue + elif char == SOH: + self.log.debug('recv: SOH') + break + elif char == STX: + self.log.debug('recv: STX') + break + elif char == CAN: + if cancel: + self.log.info('Transmission canceled: received 2xCAN ' + 'at start-sequence') + return None + else: + self.log.debug('cancellation at start sequence.') + cancel = 1 + else: + error_count += 1 + + # read data + error_count = 0 + income_size = 0 + packet_size = 128 + sequence = 1 + cancel = 0 + while True: + while True: + if char == SOH: + if packet_size != 128: + self.log.debug('recv: SOH, using 128b packet_size') + packet_size = 128 + break + elif char == STX: + if packet_size != 1024: + self.log.debug('recv: SOH, using 1k packet_size') + packet_size = 1024 + break + elif char == EOT: + # We received an EOT, so send an ACK and return the + # received data length. + self.putc(ACK) + self.log.info("Transmission complete, %d bytes", + income_size) + return income_size + elif char == CAN: + # cancel at two consecutive cancels + if cancel: + self.log.info('Transmission canceled: received 2xCAN ' + 'at block %d', sequence) + return None + else: + self.log.debug('cancellation at block %d', sequence) + cancel = 1 + else: + err_msg = ('recv error: expected SOH, EOT; ' + 'got {0!r}'.format(char)) + if not quiet: + print(err_msg, file=sys.stderr) + self.log.warn(err_msg) + error_count += 1 + if error_count > retry: + self.log.info('error_count reached %d, aborting.', + retry) + self.abort() + return None + + # read sequence + error_count = 0 + cancel = 0 + self.log.debug('recv: data block %d', sequence) + seq1 = self.getc(1, timeout) + if seq1 is None: + self.log.warn('getc failed to get first sequence byte') + seq2 = None + else: + seq1 = ord(seq1) + seq2 = self.getc(1, timeout) + if seq2 is None: + self.log.warn('getc failed to get second sequence byte') + else: + # second byte is the same as first as 1's complement + seq2 = 0xff - ord(seq2) + + if not (seq1 == seq2 == sequence): + # consume data anyway ... even though we will discard it, + # it is not the sequence we expected! + self.log.error('expected sequence %d, ' + 'got (seq1=%r, seq2=%r), ' + 'receiving next block, will NAK.', + sequence, seq1, seq2) + self.getc(packet_size + 1 + crc_mode) + else: + # sequence is ok, read packet + # packet_size + checksum + data = self.getc(packet_size + 1 + crc_mode, timeout) + valid, data = self._verify_recv_checksum(crc_mode, data) + + # valid data, append chunk + if valid: + income_size += len(data) + stream.write(data) + self.putc(ACK) + sequence = (sequence + 1) % 0x100 + # get next start-of-header byte + char = self.getc(1, timeout) + continue + + # something went wrong, request retransmission + self.log.warn('recv error: purge, requesting retransmission (NAK)') + while True: + # When the receiver wishes to , it should call a "PURGE" + # subroutine, to wait for the line to clear. Recall the sender + # tosses any characters in its UART buffer immediately upon + # completing sending a block, to ensure no glitches were mis- + # interpreted. The most common technique is for "PURGE" to + # call the character receive subroutine, specifying a 1-second + # timeout, and looping back to PURGE until a timeout occurs. + # The is then sent, ensuring the other end will see it. + data = self.getc(1, timeout=1) + if data is None: + break + self.putc(NAK) + # get next start-of-header byte + char = self.getc(1, timeout) + continue + + def _verify_recv_checksum(self, crc_mode, data): + if crc_mode: + _checksum = bytearray(data[-2:]) + their_sum = (_checksum[0] << 8) + _checksum[1] + data = data[:-2] + + our_sum = self.calc_crc(data) + valid = bool(their_sum == our_sum) + if not valid: + self.log.warn('recv error: checksum fail ' + '(theirs=%04x, ours=%04x), ', + their_sum, our_sum) + else: + _checksum = bytearray([data[-1]]) + their_sum = _checksum[0] + data = data[:-1] + + our_sum = self.calc_checksum(data) + valid = their_sum == our_sum + if not valid: + self.log.warn('recv error: checksum fail ' + '(theirs=%02x, ours=%02x)', + their_sum, our_sum) + return valid, data + + def calc_checksum(self, data, checksum=0): + ''' + Calculate the checksum for a given block of data, can also be used to + update a checksum. + + >>> csum = modem.calc_checksum('hello') + >>> csum = modem.calc_checksum('world', csum) + >>> hex(csum) + '0x3c' + + ''' + if platform.python_version_tuple() >= ('3', '0', '0'): + return (sum(data) + checksum) % 256 + else: + return (sum(map(ord, data)) + checksum) % 256 + + def calc_crc(self, data, crc=0): + ''' + Calculate the Cyclic Redundancy Check for a given block of data, can + also be used to update a CRC. + + >>> crc = modem.calc_crc('hello') + >>> crc = modem.calc_crc('world', crc) + >>> hex(crc) + '0xd5e3' + + ''' + for char in bytearray(data): + crctbl_idx = ((crc >> 8) ^ char) & 0xff + crc = ((crc << 8) ^ self.crctable[crctbl_idx]) & 0xffff + return crc & 0xffff + + +XMODEM1k = partial(XMODEM, mode='xmodem1k') +YMODEM = partial(XMODEM, mode='ymodem') + + +def run(): + import optparse + import subprocess + + parser = optparse.OptionParser( + usage='%prog [] filename filename') + parser.add_option('-m', '--mode', default='xmodem', + help='XMODEM mode (xmodem, xmodem1k, ymodem)') + + options, args = parser.parse_args() + if options.mode != 'ymodem' and len(args) != 3: + parser.error('invalid arguments') + return 1 + elif len(args) < 2: + parser.error('invalid arguments') + return 1 + elif args[0] not in ('send', 'recv'): + parser.error('invalid mode') + return 1 + + def _func(so, si): + import select + + print(('si', si)) + print(('so', so)) + + def getc(size, timeout=3): + read_ready, _, _ = select.select([so], [], [], timeout) + if read_ready: + data = so.read(size) + else: + data = None + + print(('getc(', repr(data), ')')) + return data + + def putc(data, timeout=3): + _, write_ready, _ = select.select([], [si], [], timeout) + if write_ready: + si.write(data) + si.flush() + size = len(data) + else: + size = None + + print(('putc(', repr(data), repr(size), ')')) + return size + + return getc, putc + + def _pipe(*command): + pipe = subprocess.Popen(command, + stdout=subprocess.PIPE, + stdin=subprocess.PIPE) + return pipe.stdout, pipe.stdin + + if args[0] == 'recv': + getc, putc = _func(*_pipe('sz', '--xmodem', args[2])) + stream = open(args[1], 'wb') + xmodem = XMODEM(getc, putc, mode=options.mode) + status = xmodem.recv(stream, retry=8) + assert status, ('Transfer failed, status is', False) + stream.close() + + elif args[0] == 'send': + rzargs = ['rz'] + if options.mode == 'ymodem': + rzargs += ['--ymodem'] + else: + rzargs += ['--xmodem'] + rzargs += args[2] + getc, putc = _func(*_pipe(*rzargs)) + if options.mode != 'ymodem': + stream = open(args[1], 'rb') + else: + stream = args[1:] + xmodem = XMODEM(getc, putc, mode=options.mode) + sent = xmodem.send(stream, retry=8) + assert sent is not None, ('Transfer failed, sent is', sent) + if options.mode != 'ymodem': + stream.close() + +if __name__ == '__main__': + sys.exit(run())