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Diffstat (limited to 'edi/edisend.py')
| -rwxr-xr-x | edi/edisend.py | 193 |
1 files changed, 193 insertions, 0 deletions
diff --git a/edi/edisend.py b/edi/edisend.py new file mode 100755 index 0000000..2bd6bc1 --- /dev/null +++ b/edi/edisend.py @@ -0,0 +1,193 @@ +#!/usr/bin/env python2 +# +# Read an EDI dump file and transmit over UDP +# +# The MIT License (MIT) +# +# Copyright (c) 2015 Matthias P. Braendli +# +# Permission is hereby granted, free of charge, to any person obtaining a copy +# of this software and associated documentation files (the "Software"), to deal +# in the Software without restriction, including without limitation the rights +# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell +# copies of the Software, and to permit persons to whom the Software is +# furnished to do so, subject to the following conditions: +# +# The above copyright notice and this permission notice shall be included in +# all copies or substantial portions of the Software. +# +# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR +# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, +# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE +# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER +# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, +# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN +# THE SOFTWARE. + +import sys +import struct + +from crc import crc16 +from reedsolo import RSCodec + +import socket +import time + +UDP_IP = "239.20.64.1" +UDP_PORT = 12002 + +class BufferedFile: + def __init__(self, fname): + self.buf = [] + + if fname == "-": + self.fd = sys.stdin + else: + self.fd = open(fname, "rb") + + def read(self, n): + if not self.buf: + return self.fd.read(n) + else: + if len(self.buf) < n: + self.buf.extend(self.fd.read(n - len(self.buf))) + + if len(self.buf) == n: + ret = b"".join(self.buf) + self.buf = [] + else: + ret = b"".join(self.buf[:n]) + del self.buf[:n] + + return ret + + def peek(self, n): + dat = self.fd.read(n) + self.buf.extend(dat) + return dat + + +pft_head_struct = "!2sH3B3BH" +pft_rs_head_struct = "!2B" +pft_addr_head_struct = "!2H" +af_head_struct = "!2sLHBc" +class EDI: + def __init__(self): + self.last_send_time = time.time() + self.sock = socket.socket(socket.AF_INET, # Internet + socket.SOCK_DGRAM) # UDP + + def send_udp(self, message): + self.sock.sendto(message, (UDP_IP, UDP_PORT)) + + + def decode(self, stream): + sync = stream.peek(2) + + if len(sync) < 2: + return False + + if sync == "PF": + return self.decode_pft(stream) + elif sync == "AF": + return self.decode_af(stream, is_stream=True) + + + + def decode_pft(self, stream): + headerdata = stream.read(12) + header = struct.unpack(pft_head_struct, headerdata) + + psync, pseq, findex1, findex2, findex3, fcount1, fcount2, fcount3, fec_ad_plen = header + + findex = (findex1 << 16) | (findex2 << 8) | findex3 + fcount = (fcount1 << 16) | (fcount2 << 8) | fcount3 + + fec = (fec_ad_plen & 0x8000) != 0x00 + addr = (fec_ad_plen & 0x4000) != 0x00 + plen = fec_ad_plen & 0x3FFF + + rs_k = 0 + rs_z = 0 + if fec: + rs_head = stream.read(2) + rs_k, rs_z = struct.unpack(pft_rs_head_struct, rs_head) + headerdata += rs_head + + addr_source = 0 + addr_dest = 0 + if addr: + addr_head = stream.read(4) + addr_source, addr_dest = struct.unpack(pft_addr_head_struct, addr_head) + headerdata += addr_head + + # read CRC + crc_data = stream.read(2) + crc = struct.unpack("!H", crc_data)[0] + + crc_calc = crc16(headerdata) + crc_calc ^= 0xFFFF + + crc_ok = crc_calc == crc + + time_now = time.time() + if findex == 0: + if self.last_send_time + 24e-3 > time_now: + delay = self.last_send_time + 24e-3 - time_now + print("Sleeping for {} ms".format(1000 * delay)) + time.sleep(delay) + self.last_send_time = time_now + + + if crc_ok: + payload = stream.read(plen) + self.send_udp(headerdata + crc_data + payload) + + return crc_ok + + + def decode_af(self, in_data, is_stream=False): + if is_stream: + headerdata = in_data.read(10) + else: + headerdata = in_data[:10] + + sync, plen, seq, ar, pt = struct.unpack(af_head_struct, headerdata) + + if sync != "AF": + return False + + crc_flag = (ar & 0x80) != 0x00 + revision = ar & 0x7F + + if is_stream: + payload = in_data.read(plen) + crc_data = in_data.read(2) + crc = struct.unpack("!H", crc_data)[0] + else: + payload = in_data[10:10+plen] + crc_data = in_data[10+plen:10+plen+2] + crc = struct.unpack("!H", crc_data)[0] + + crc_calc = crc16(headerdata) + crc_calc = crc16(payload, crc_calc) + crc_calc ^= 0xFFFF + + crc_ok = crc_calc == crc + + if crc_ok: + self.send_udp(headerdata + payload + crc_data) + + return crc_ok + +if len(sys.argv) > 1: + filename = sys.argv[1] + + edi_fd = BufferedFile(filename) +else: + edi_fd = BufferedFile("-") + +edi = EDI() +while edi.decode(edi_fd): + pass + |