mirror of
https://github.com/trezor/trezor-firmware.git
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81 lines
2.5 KiB
Python
81 lines
2.5 KiB
Python
# This file is part of the TREZOR project.
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#
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# Copyright (C) 2012-2016 Marek Palatinus <slush@satoshilabs.com>
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# Copyright (C) 2012-2016 Pavol Rusnak <stick@satoshilabs.com>
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#
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# This library is free software: you can redistribute it and/or modify
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# it under the terms of the GNU Lesser General Public License as published by
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# the Free Software Foundation, either version 3 of the License, or
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# (at your option) any later version.
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#
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# This library is distributed in the hope that it will be useful,
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# but WITHOUT ANY WARRANTY; without even the implied warranty of
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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# GNU Lesser General Public License for more details.
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#
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# You should have received a copy of the GNU Lesser General Public License
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# along with this library. If not, see <http://www.gnu.org/licenses/>.
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from __future__ import absolute_import
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import struct
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from . import mapping
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REPLEN = 64
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class ProtocolV1(object):
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def session_begin(self, transport):
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pass
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def session_end(self, transport):
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pass
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def write(self, transport, msg):
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ser = msg.SerializeToString()
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header = struct.pack(">HL", mapping.get_type(msg), len(ser))
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data = bytearray(b"##" + header + ser)
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while data:
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# Report ID, data padded to 63 bytes
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chunk = b'?' + data[:REPLEN - 1]
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chunk = chunk.ljust(REPLEN, b'\x00')
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transport.write_chunk(chunk)
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data = data[63:]
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def read(self, transport):
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# Read header with first part of message data
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chunk = transport.read_chunk()
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(msg_type, datalen, data) = self.parse_first(chunk)
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# Read the rest of the message
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while len(data) < datalen:
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chunk = transport.read_chunk()
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data.extend(self.parse_next(chunk))
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# Strip padding zeros
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data = data[:datalen]
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# Parse to protobuf
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msg = mapping.get_class(msg_type)()
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msg.ParseFromString(bytes(data))
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return msg
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def parse_first(self, chunk):
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if chunk[:3] != b'?##':
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raise Exception('Unexpected magic characters')
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try:
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headerlen = struct.calcsize('>HL')
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(msg_type, datalen) = struct.unpack('>HL', bytes(chunk[3:3 + headerlen]))
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except:
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raise Exception('Cannot parse header')
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data = chunk[3 + headerlen:]
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return (msg_type, datalen, data)
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def parse_next(self, chunk):
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if chunk[:1] != b'?':
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raise Exception('Unexpected magic characters')
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return chunk[1:]
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