├── .gitignore ├── requirements.txt ├── timeservice.py ├── kiss.py ├── README.md ├── free-outernet.py ├── protocols.py ├── files.py └── LICENSE /.gitignore: -------------------------------------------------------------------------------- 1 | __pycache__/ 2 | *.pyc 3 | -------------------------------------------------------------------------------- /requirements.txt: -------------------------------------------------------------------------------- 1 | crcmod>=1.7,<2 2 | zfec>=1.5,<2 3 | -------------------------------------------------------------------------------- /timeservice.py: -------------------------------------------------------------------------------- 1 | # Copyright 2016 Daniel Estevez . 2 | # 3 | # This is free software; you can redistribute it and/or modify 4 | # it under the terms of the GNU General Public License as published by 5 | # the Free Software Foundation; either version 3, or (at your option) 6 | # any later version. 7 | # 8 | # This software is distributed in the hope that it will be useful, 9 | # but WITHOUT ANY WARRANTY; without even the implied warranty of 10 | # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 11 | # GNU General Public License for more details. 12 | # 13 | # You should have received a copy of the GNU General Public License 14 | # along with this software; see the file COPYING. If not, write to 15 | # the Free Software Foundation, Inc., 51 Franklin Street, 16 | # Boston, MA 02110-1301, USA. 17 | 18 | """Outernet time service receiver 19 | 20 | Receives time packets in the Outernet service 21 | """ 22 | 23 | __author__ = 'Daniel Estevez' 24 | __copyright__ = 'Copyright 2016, Daniel Estevez' 25 | __license__ = 'GPLv3' 26 | __maintainer__ = 'Daniel Estevez' 27 | __email__ = 'daniel@destevez.net' 28 | 29 | 30 | import datetime 31 | import struct 32 | 33 | class TimeService: 34 | """ 35 | Packet handler for Outernet time service 36 | 37 | Gets time packets from LDPRouter() and prints them 38 | """ 39 | def __init__(self, router): 40 | """ 41 | Initialize time service handler 42 | 43 | Args: 44 | router (LDPRouter): LDP router to get packets from 45 | """ 46 | router.register(self.__get, 0x81) 47 | 48 | def __get(self, packet): 49 | """ 50 | Time packet handler 51 | 52 | Prints the timestamp in the packet 53 | 54 | Args: 55 | packet (LDP): the LDP time packet 56 | """ 57 | payload = packet.payload 58 | while len(payload) > 2: 59 | desc_id, desc_len = struct.unpack('>BB', payload[0:2]) 60 | if desc_len > len(payload) - 2: 61 | break 62 | data = payload[2:desc_len+2] 63 | payload = payload[desc_len+2:] 64 | if desc_id == 0x01: 65 | server_id = str(data, 'utf-8') 66 | print('[Time service] Server ID: {}'.format(server_id)) 67 | elif desc_id == 0x02 and len(data) == 8: 68 | timestamp = datetime.datetime.utcfromtimestamp(struct.unpack('>Q', data)[0]) 69 | print('[Time service] Server time: {} UTC'.format(timestamp)) 70 | else: 71 | print('[Time service] Unknown descriptor {:02x}'.format(desc_id)) 72 | -------------------------------------------------------------------------------- /kiss.py: -------------------------------------------------------------------------------- 1 | # Copyright 2016 Daniel Estevez . 2 | # 3 | # This is free software; you can redistribute it and/or modify 4 | # it under the terms of the GNU General Public License as published by 5 | # the Free Software Foundation; either version 3, or (at your option) 6 | # any later version. 7 | # 8 | # This software is distributed in the hope that it will be useful, 9 | # but WITHOUT ANY WARRANTY; without even the implied warranty of 10 | # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 11 | # GNU General Public License for more details. 12 | # 13 | # You should have received a copy of the GNU General Public License 14 | # along with this software; see the file COPYING. If not, write to 15 | # the Free Software Foundation, Inc., 51 Franklin Street, 16 | # Boston, MA 02110-1301, USA. 17 | 18 | """KISS framing library""" 19 | 20 | __author__ = 'Daniel Estevez' 21 | __copyright__ = 'Copyright 2016, Daniel Estevez' 22 | __license__ = 'GPLv3' 23 | __maintainer__ = 'Daniel Estevez' 24 | __email__ = 'daniel@destevez.net' 25 | 26 | import collections 27 | 28 | class KISSDeframer(): 29 | """ 30 | Deframe a stream of bytes into KISS frames 31 | """ 32 | __FEND = 0xc0 33 | __FESC = 0xdb 34 | __TFEND = 0xdc 35 | __TFESC = 0xdd 36 | 37 | def __init__(self): 38 | """ 39 | Initialize KISS deframer 40 | """ 41 | self.__kiss = collections.deque() 42 | self.__pdu = bytearray() 43 | self.__transpose = False 44 | 45 | def push(self, data): 46 | """ 47 | Push a chunk of data bytes into the deframer 48 | 49 | Returns a list of the frames that have being 50 | successfully deframed (in the same order as in the stream) 51 | 52 | Args: 53 | data (bytes): the chunk of bytes to push 54 | """ 55 | pdus = list() 56 | 57 | self.__kiss.extend(data) 58 | 59 | while self.__kiss: 60 | c = self.__kiss.popleft() 61 | if c == self.__FEND: 62 | if self.__pdu and not self.__pdu[0] & 0x0f: 63 | pdus.append(bytes(self.__pdu[1:])) 64 | self.__pdu = bytearray() 65 | elif self.__transpose: 66 | if c == self.__TFEND: 67 | self.__pdu.append(self.__FEND) 68 | elif c == self.__TFESC: 69 | self.__pdu.append(self.__FESC) 70 | self.__transpose = False 71 | elif c == self.__FESC: 72 | self.__transpose = True 73 | else: 74 | self.__pdu.append(c) 75 | 76 | return pdus 77 | -------------------------------------------------------------------------------- /README.md: -------------------------------------------------------------------------------- 1 | # free-outernet 2 | Free Software Outernet receiver 3 | 4 | **Note:** This software is now maintained by [Othernet](https://othernet.is/) as 5 | [open-ondd](https://github.com/Othernet-Project/open-ondd). The new open-ondd has 6 | been updated to work with the current Othernet data broadcast protocols. 7 | 8 | This is a Free Software (Open Source) receiver for 9 | [Outernet](http://outernet.is/) designed to work with the 10 | [gr-outernet](https://github.com/daniestevez/gr-outernet) GNUradio Outernet 11 | receiver modem. The key parts of the official Outernet receiver software, `ondd` 12 | and `sdr100` are closed-source, distributed as binaries only. This project aims 13 | to provide a Free Software alternative to `ondd`, while 14 | [gr-outernet](https://github.com/daniestevez/gr-outernet) can be used a a 15 | substitute for `sdr100`. 16 | 17 | With free-outernet and gr-outernet you can receive the files that are broadcast 18 | by Outernet file service and the time packets that are broadcast by the Outernet 19 | time service. 20 | 21 | All this software is the result of a reverse engineering effort, since Outernet 22 | does not publish any documentation for the protocols they use. 23 | 24 | You can use `free-outernet.py` to receive UDP packets in real-time from 25 | gr-outernet or with a KISS file recorded previously by 26 | gr-outernet. `free-outernet.py` recovers the files that are transmitted by 27 | Outernet and prints the time packets. It also prints some interesting debug info. 28 | 29 | 30 | Things that are not implemented/supported yet: 31 | 32 | * X.509 signature checking. The file announcements of the Outernet file service 33 | are signed with the Outernet X.509 certificate to prevent spoofing. This will 34 | not be implemented, as I have no interest in checking the signature. Perhaps 35 | some Amateur Radio operators or other people whish to use the Outernet 36 | protocols to exchange files, so it does not make sense for me to require 37 | that file announcements are signed. 38 | * Using the time packets to set the system time. I do not know how useful it 39 | is for most people. `ondd` does it, because it is designed to run standanlone 40 | without internet conetivity. If you have Internet connectivity it is much 41 | better to use NTP. If you do not have Internet connectivity and/or your need 42 | precise timing, it is better to use GPS. The Outernet time service only has a 43 | resolution of 1 second and it does not seem to account for round trip time to 44 | geostationary orbit (around 200ms). 45 | * Automatic decompression of received files. Most (perhaps all) files sent by 46 | the Outernet file service are `.tar.bz2` files. `ondd` extracts the files 47 | automatically. This is easy to implement, but it is low on my priority list, 48 | as it is very easy to do this manually. 49 | 50 | ## Dependencies 51 | 52 | To install all dependencies just run: `pip3 install -r requirements.txt` 53 | 54 | * [crcmod](https://pypi.python.org/pypi/crcmod) 55 | * [zfec](https://pypi.python.org/pypi/zfec) 56 | 57 | ## Sample KISS files 58 | 59 | You can use some 60 | [sample KISS files](https://drive.google.com/file/d/0B2pPGQkeEAfdbXFZNThCb1BLMzg/view?usp=sharing&resourcekey=0-itJm_p_plfZzA3kBHzjAVQ) 61 | for testing. 62 | 63 | ## About LDPC decoding for files 64 | 65 | LDPC decoding has been [implemented by George 66 | Hopkins](https://github.com/daniestevez/free-outernet/pull/4) by reverse 67 | engineering `ondd`. 68 | 69 | Previously, this was not implemented, so `free-outernet` needed to receive all 70 | the blocks for a file to be able to reconstruct it correctly. Now, it can use 71 | the LDPC to "fill in" the missing packets in case some of them were lost. 72 | 73 | The performance of `free-outernet` regarding FEC and LDPC decoding should 74 | be now the same as the performance of `ondd`. 75 | -------------------------------------------------------------------------------- /free-outernet.py: -------------------------------------------------------------------------------- 1 | #!/usr/bin/env python3 2 | # 3 | # Copyright 2016 Daniel Estevez . 4 | # 5 | # This is free software; you can redistribute it and/or modify 6 | # it under the terms of the GNU General Public License as published by 7 | # the Free Software Foundation; either version 3, or (at your option) 8 | # any later version. 9 | # 10 | # This software is distributed in the hope that it will be useful, 11 | # but WITHOUT ANY WARRANTY; without even the implied warranty of 12 | # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 13 | # GNU General Public License for more details. 14 | # 15 | # You should have received a copy of the GNU General Public License 16 | # along with this software; see the file COPYING. If not, write to 17 | # the Free Software Foundation, Inc., 51 Franklin Street, 18 | # Boston, MA 02110-1301, USA. 19 | 20 | 21 | import kiss 22 | import protocols 23 | import timeservice 24 | import files 25 | 26 | import sys 27 | import os 28 | import getopt 29 | import socket 30 | import struct 31 | 32 | UDP_PORT = 10000 33 | # Use UDP_HOST = '0.0.0.0' if you want IPv4 only 34 | UDP_HOST = '::' 35 | 36 | BUFSIZE = 4096 37 | 38 | opDefragmenter = protocols.OPDefragmenter() 39 | router = protocols.LDPRouter() 40 | 41 | groundstationMac = None 42 | BROADCAST_MAC = b'\xff'*6 43 | ETHERTYPE = b'\x8f\xff' 44 | 45 | def printMac(mac): 46 | return ('%02x:'* 5 + '%02x') % struct.unpack('B'*6, mac) 47 | 48 | def printEthertype(ethertype): 49 | return hex(struct.unpack('>H', ethertype)[0]) 50 | 51 | def processFrame(frame): 52 | global groundstationMac 53 | if len(frame) < 14: 54 | return 55 | srcmac = frame[6:12] 56 | dstmac = frame[:6] 57 | ethertype = frame[12:14] 58 | if dstmac != BROADCAST_MAC or ethertype != ETHERTYPE: 59 | print('Received interesting Ethernet frame with src MAC {}, dst MAC {} and ethertype {}'.format(printMac(srcmac), printMac(dstmac), printEthertype(ethertype))) 60 | if srcmac != groundstationMac: 61 | print('Receiving Ethernet frames from groundstation with MAC {}'.format(printMac(srcmac))) 62 | groundstationMac = srcmac 63 | try: 64 | packet = opDefragmenter.push(protocols.OP(frame[14:])) 65 | except ValueError: 66 | return 67 | if not packet: 68 | return 69 | try: 70 | packet = protocols.LDP(packet) 71 | except ValueError as e: 72 | print(e) 73 | return 74 | router.route(packet) 75 | 76 | def getSocket(): 77 | s = None 78 | for res in socket.getaddrinfo(UDP_HOST, UDP_PORT, socket.AF_UNSPEC, socket.SOCK_DGRAM, 0, 79 | socket.AI_PASSIVE): 80 | af, socktype, proto, canonname, sa = res 81 | try: 82 | s = socket.socket(af, socktype, proto) 83 | except OSError as msg: 84 | print('Socket error', msg) 85 | continue 86 | try: 87 | s.bind(sa) 88 | except OSError as msg: 89 | print('Bind error', msg) 90 | s.close() 91 | continue 92 | break 93 | return s 94 | 95 | def usage(): 96 | print('Usage: {} [OPTIONS]'.format(sys.argv[0])) 97 | print('') 98 | print('By default, {} will listen on a UDP socket for Outernet frames'.format(sys.argv[0])) 99 | print('If you want to use a KISS file as input, you must use the -k option') 100 | print('') 101 | print('''Options: 102 | \t-h, --help\t\tHelp 103 | \t-o, --output=DIR\tDirectory to use to save files (defaults to the current directory) 104 | \t-k, --kiss=FILE\t\tKISS file to use as input 105 | \t-p, --port=PORT\t\tUDP port to listen (default {}) 106 | \t --host=HOST\t\tUDP host to listen (default ::, use 0.0.0.0 for IPv4 only) 107 | '''.format(UDP_PORT)) 108 | 109 | 110 | def main(): 111 | try: 112 | opts, args = getopt.getopt(sys.argv[1:], 'ho:k:p:', 113 | ['help', 'output=', 'kiss=', 'port=', 'host=']) 114 | except getopt.GetoptError as err: 115 | print(err) 116 | usage() 117 | sys.exit(1) 118 | output = os.getcwd() 119 | kissinput = None 120 | port = UDP_PORT 121 | host = UDP_HOST 122 | for o, a in opts: 123 | if o in ('-h', '--help'): 124 | usage() 125 | sys.exit() 126 | elif o in ('-o', '--output'): 127 | output = a 128 | elif o in ('-k', '--kiss'): 129 | kissinput = a 130 | elif o in ('-p', '--port'): 131 | if kissinput: 132 | print('UDP port cannot be used with KISS file input') 133 | usage() 134 | sys.exit(1) 135 | port = int(a) 136 | elif o == '--host': 137 | if kissinput: 138 | print('UDP host cannot be used with KISS file input') 139 | usage() 140 | sys.exit(1) 141 | host = a 142 | else: 143 | print('Invalid option') 144 | usage() 145 | sys.exit(1) 146 | 147 | timeservice.TimeService(router) 148 | files.FileService(router, output) 149 | 150 | if kissinput: 151 | kissFile = open(kissinput, 'rb') 152 | kissDeframer = kiss.KISSDeframer() 153 | frames = kissDeframer.push(kissFile.read()) 154 | for frame in frames: 155 | processFrame(frame) 156 | else: 157 | s = getSocket() 158 | while True: 159 | try: 160 | frame = s.recv(BUFSIZE) 161 | except KeyboardInterrupt: 162 | print('') 163 | sys.exit() 164 | processFrame(frame) 165 | 166 | if __name__ == '__main__': 167 | main() 168 | -------------------------------------------------------------------------------- /protocols.py: -------------------------------------------------------------------------------- 1 | # Copyright 2016 Daniel Estevez . 2 | # 3 | # This is free software; you can redistribute it and/or modify 4 | # it under the terms of the GNU General Public License as published by 5 | # the Free Software Foundation; either version 3, or (at your option) 6 | # any later version. 7 | # 8 | # This software is distributed in the hope that it will be useful, 9 | # but WITHOUT ANY WARRANTY; without even the implied warranty of 10 | # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 11 | # GNU General Public License for more details. 12 | # 13 | # You should have received a copy of the GNU General Public License 14 | # along with this software; see the file COPYING. If not, write to 15 | # the Free Software Foundation, Inc., 51 Franklin Street, 16 | # Boston, MA 02110-1301, USA. 17 | # 18 | 19 | """Outernet OP and LDP protocols""" 20 | 21 | __author__ = 'Daniel Estevez' 22 | __copyright__ = 'Copyright 2016, Daniel Estevez' 23 | __license__ = 'GPLv3' 24 | __maintainer__ = 'Daniel Estevez' 25 | __email__ = 'daniel@destevez.net' 26 | 27 | 28 | import struct 29 | import zfec 30 | from crcmod.predefined import PredefinedCrc 31 | 32 | class OP: 33 | """ 34 | Outernet Protocol (OP) packet 35 | 36 | OP is the L3 protocol of Outernet 37 | """ 38 | __header_len = 6 39 | 40 | def __init__(self, data): 41 | """ 42 | Create OP packet 43 | 44 | Returns a new OP packet 45 | Args: 46 | data (bytes): packet contents 47 | 48 | Throws ValueError if packet is malformed 49 | """ 50 | 51 | header = data[:self.__header_len] 52 | if len(header) < self.__header_len: 53 | raise ValueError('Malformed OP packet: too short') 54 | 55 | self.length, self.fragment_type, self.carousel_id, \ 56 | self.last_fragment, self.fragment_index = struct.unpack('>HBBBB', header) 57 | self.payload = data[self.__header_len : self.__header_len + self.length - 4] 58 | 59 | class PartialLDP: 60 | """ 61 | Fragmented LDP packet 62 | 63 | A LDP packet which has not yet been completely received. 64 | """ 65 | def __init__(self): 66 | self.reset() 67 | 68 | """ 69 | Reset the internal state 70 | """ 71 | def reset(self): 72 | self.__fragments = {} 73 | self.__frag_recv = 0 74 | self.__fec_recv = 0 75 | self.frag_size = None 76 | self.frag_count = None 77 | self.fec_count = None 78 | self.next_index = 0 79 | 80 | """ 81 | Push a data block 82 | 83 | Args: 84 | index (int): the index of the fragment 85 | payload (bytes): the actual data 86 | """ 87 | def push_data(self, index, payload): 88 | if index in self.__fragments: 89 | return 90 | self.__fragments[index] = payload 91 | self.__frag_recv += 1 92 | 93 | """ 94 | Push a FEC block 95 | 96 | Args: 97 | index (int): the index of the FEC block 98 | payload (bytes): the actual FEC data 99 | """ 100 | def push_fec(self, index, payload): 101 | if not self.frag_count or (self.frag_count + index) in self.__fragments: 102 | return 103 | self.__fragments[self.frag_count + index] = payload 104 | self.__fec_recv += 1 105 | 106 | """ 107 | Indicates whether a reconstruction is possible 108 | """ 109 | @property 110 | def complete(self): 111 | return self.frag_count and self.__fec_recv + self.__frag_recv >= self.frag_count 112 | 113 | """ 114 | Decode the packet 115 | """ 116 | def decode(self): 117 | if self.__frag_recv == self.frag_count: # No error FEC decoding necessary 118 | return b''.join([self.__fragments[s] for s in range(self.frag_count)]) 119 | k = self.frag_count 120 | n = k + self.fec_count 121 | decoder = zfec.Decoder(k, n) 122 | sharenums = list(self.__fragments.keys()) 123 | if len(sharenums) != k: 124 | print("[ERROR] Unexpected number of fragments. k = {}, sharenums = {}".format(k, sharenums)) 125 | return 126 | return b''.join(decoder.decode([self.__fragments[s] for s in sharenums], sharenums)) 127 | 128 | class OPDefragmenter: 129 | """ 130 | OP defragmenter 131 | 132 | Performs defragmentation of OP packets. New packets can be pushed 133 | with .push(), which will return an L4 packet if defragmentation 134 | is successful 135 | """ 136 | def __init__(self): 137 | """ 138 | Initialize defragmenter 139 | """ 140 | self.__pending = {} 141 | 142 | def push(self, packet): 143 | """ 144 | Push new packet into defragmenter 145 | 146 | Returns a payload (bytes) if defragmentation is succesful, 147 | None otherwise 148 | 149 | Args: 150 | packet (OP): Packet to push 151 | """ 152 | ldp = self.__pending.get(packet.carousel_id) 153 | if not ldp: 154 | ldp = PartialLDP() 155 | self.__pending[packet.carousel_id] = ldp 156 | 157 | if packet.fragment_type == 0x3c or packet.fragment_type == 0xc3: 158 | if packet.fragment_type == 0x3c and packet.fragment_index == 0: # TODO Verify correctness 159 | return packet.payload 160 | if packet.fragment_index < ldp.next_index: 161 | ldp.reset() 162 | if not ldp.frag_size: 163 | ldp.frag_size = packet.length - 4 164 | if not ldp.frag_count: 165 | ldp.frag_count = packet.last_fragment + 1 166 | ldp.next_index = packet.fragment_index + 1 167 | ldp.push_data(packet.fragment_index, packet.payload + b'\xff' * (ldp.frag_size - len(packet.payload))) 168 | if packet.fragment_type == 0x3c and ldp.complete: 169 | decoded = ldp.decode() 170 | ldp.reset() 171 | return decoded 172 | elif packet.fragment_type == 0x69: 173 | if not ldp.frag_size: 174 | return 175 | if not ldp.fec_count: 176 | ldp.fec_count = packet.last_fragment + 1 177 | ldp.push_fec(packet.fragment_index, packet.payload) 178 | if ldp.complete: 179 | decoded = ldp.decode() 180 | ldp.reset() 181 | return decoded 182 | else: 183 | print('Unsupported fragment type: {:02x}'.format(packet.fragment_type)) 184 | 185 | class LDP: 186 | """ 187 | Lightweight Datagram Protocol (LDP) packet 188 | 189 | LDP is the L4 protocol of Outernet 190 | """ 191 | __header_len = 4 192 | __checksum_len = 4 193 | 194 | def __init__(self, data): 195 | """ 196 | Create an LDP packet 197 | 198 | Returns a new LDP packet 199 | Args: 200 | data (bytes) : packet contents 201 | 202 | Throws ValueError if packet is malformed 203 | """ 204 | if len(data) < self.__header_len + self.__checksum_len: 205 | raise ValueError('Malformed LDP packet: too short') 206 | header = struct.unpack('>L', data[:self.__header_len])[0] 207 | self.type = header >> 24 208 | self.length = header & 0xffffff 209 | if self.length > len(data): 210 | raise ValueError('Malformed LDP packet: invalid length') 211 | 212 | crc = PredefinedCrc('crc-32-mpeg') 213 | crc.update(data[:self.length]) 214 | if crc.crcValue != 0: 215 | raise ValueError('Malformed LDP packet: invalid checksum') 216 | 217 | self.payload = data[self.__header_len:self.length-self.__checksum_len] 218 | 219 | class LDPRouter: 220 | """ 221 | LDP router 222 | 223 | Sends an LDP packet to the appropriate function according to the 224 | a and b fields in the LDP packet. The packet handler functions 225 | are previously registered whith LDPRouter().register() 226 | """ 227 | def __init__(self): 228 | """ 229 | Create a new LDP router 230 | """ 231 | self.__registrations = dict() 232 | 233 | def route(self, packet): 234 | """ 235 | Push an LDP packet into the router, calling the appropriate 236 | packet handler function 237 | 238 | Args: 239 | packet (LDP): packet to route 240 | """ 241 | if packet.type not in self.__registrations: 242 | print('Unknown routing for packet with type {:02x}'.format(packet.type)) 243 | else: 244 | self.__registrations[packet.type](packet) 245 | 246 | def register(self, fun, type): 247 | """ 248 | Register a packet handler 249 | 250 | Args: 251 | fun: packet handler function (it must take a single argument of type LDP) 252 | type: type of the packets to handle 253 | """ 254 | self.__registrations[type] = fun 255 | -------------------------------------------------------------------------------- /files.py: -------------------------------------------------------------------------------- 1 | # Copyright 2016 Daniel Estevez . 2 | # 3 | # This is free software; you can redistribute it and/or modify 4 | # it under the terms of the GNU General Public License as published by 5 | # the Free Software Foundation; either version 3, or (at your option) 6 | # any later version. 7 | # 8 | # This software is distributed in the hope that it will be useful, 9 | # but WITHOUT ANY WARRANTY; without even the implied warranty of 10 | # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 11 | # GNU General Public License for more details. 12 | # 13 | # You should have received a copy of the GNU General Public License 14 | # along with this software; see the file COPYING. If not, write to 15 | # the Free Software Foundation, Inc., 51 Franklin Street, 16 | # Boston, MA 02110-1301, USA. 17 | 18 | """Outernet file service receiver 19 | 20 | Receives files in the Outernet service and saves them to disk 21 | """ 22 | 23 | __author__ = 'Daniel Estevez' 24 | __copyright__ = 'Copyright 2016, Daniel Estevez' 25 | __license__ = 'GPLv3' 26 | __maintainer__ = 'Daniel Estevez' 27 | __email__ = 'daniel@destevez.net' 28 | 29 | 30 | import struct 31 | import xml.etree.ElementTree as ET 32 | import math 33 | import hashlib 34 | import os.path 35 | import os 36 | 37 | import binascii 38 | 39 | class FileService: 40 | """ 41 | Packet handler for Outernet file service 42 | 43 | Gets packets from LDPRouter() and handles file reconstruction 44 | using the File() class 45 | """ 46 | __block_header_len = 6 47 | 48 | def __init__(self, router, files_path): 49 | """ 50 | Initialize file service handler 51 | 52 | Args: 53 | router (LDPRouter): LDP router to get packets from 54 | files_path (str): path to save files to 55 | """ 56 | router.register(self.__description_packet, 0x69) 57 | router.register(self.__block_packet, 0x18) 58 | router.register(self.__fec_packet, 0xff) 59 | router.register(self.__signaling_packet, 0x42) 60 | router.register(self.__signaling_packet, 0x5a) 61 | 62 | self.__files = dict() 63 | self.__files_path = files_path 64 | self.__last_file = None 65 | 66 | def __description_packet(self, packet): 67 | """ 68 | File description packet handler 69 | 70 | Registers a new file within the file dictionary 71 | 72 | Args: 73 | packet (LDP): the LDP packet to handle 74 | """ 75 | cert_len = struct.unpack('>H', packet.payload[0:2])[0] 76 | cert = packet.payload[2:2+cert_len] 77 | signature_len = 256 # TODO: Deduce length from cert 78 | signature = packet.payload[2+cert_len:2+cert_len+signature_len] 79 | xml = packet.payload[2+cert_len+signature_len:] 80 | # TODO: Verify hash matches the signature (RSA with SHA256) 81 | f = File(xml) 82 | self.__files[f.id] = f 83 | print('[File service] New file announced: {} size {} bytes'.format(f.path, f.size)) 84 | 85 | def __block_packet(self, packet): 86 | """ 87 | File block packet handler 88 | 89 | Pushes the block to the corresponding file and 90 | initiates file recovery if this is the last packet 91 | 92 | Args: 93 | packet (LDP): the LDP packet to handle 94 | """ 95 | file_id, block_number = struct.unpack('>IH', packet.payload[:self.__block_header_len]) 96 | block = packet.payload[self.__block_header_len:] 97 | if file_id in self.__files: 98 | f = self.__files[file_id] 99 | if f is not self.__last_file and self.__last_file and self.__last_file.maybe_reconstructable: 100 | self.__try_reconstruct(self.__last_file.id) 101 | self.__last_file = f 102 | f.push_block(block, block_number) 103 | if f.reconstructable: 104 | self.__try_reconstruct(file_id) 105 | 106 | def __fec_packet(self, packet): 107 | """ 108 | File FEC packet handler 109 | 110 | Pushes the FEC block to the corresponding file 111 | 112 | Args: 113 | packet (LDP): the LDP packet to handle 114 | """ 115 | file_id, block_number = struct.unpack('>IH', packet.payload[:self.__block_header_len]) 116 | block = packet.payload[self.__block_header_len:] 117 | if file_id in self.__files: 118 | f = self.__files[file_id] 119 | f.push_fec(block, block_number) 120 | 121 | def __signaling_packet(self, packet): 122 | """ 123 | File signaling packet handler 124 | 125 | Args: 126 | packet (LDP): the LDP packet to handle 127 | """ 128 | print('[File service] Received signaling information (not implemented yet)') 129 | # TODO Update file dictionary based on signed, deflated XML 130 | 131 | def __try_reconstruct(self, file_id): 132 | """ 133 | Try to reconstruct file and save to disk 134 | 135 | Args: 136 | file_id (int): the file to reconstruct 137 | """ 138 | f = self.__files[file_id] 139 | contents = f.reconstruct() 140 | if not contents: 141 | return 142 | 143 | path = os.path.join(self.__files_path, f.path) 144 | os.makedirs(os.path.dirname(path), exist_ok = True) 145 | out = open(os.path.join(self.__files_path, f.path), 'wb') 146 | out.write(contents) 147 | out.close() 148 | del self.__files[file_id] 149 | if f is self.__last_file: 150 | self.__last_file = None 151 | print('[File service] File reconstructed: {}'.format(f.path)) 152 | 153 | 154 | class File: 155 | """ 156 | File object for file reconstruction 157 | """ 158 | def __init__(self, xml): 159 | """ 160 | Create new file 161 | 162 | Args: 163 | xml (str): XML description of the file 164 | """ 165 | root = ET.fromstring(xml) 166 | self.id = int(root.find('id').text) 167 | self.path = root.find('path').text 168 | self.hash = root.find('hash').text 169 | self.size = int(root.find('size').text) 170 | self.block_size = int(root.find('block_size').text) 171 | self.blocks = math.ceil(self.size / self.block_size) 172 | self.fec = root.find('fec') 173 | if self.fec != None: 174 | self.fec = self.fec.text 175 | self.__fec_matrix = None 176 | self.__blocks = [None] * self.blocks 177 | self.__fec_blocks = list() 178 | 179 | def push_block(self, block, n): 180 | """ 181 | Push a new block into the file 182 | 183 | Args: 184 | block (bytes): block contents 185 | n (int): block number 186 | """ 187 | if not self.__blocks[n]: 188 | self.__blocks[n] = block 189 | 190 | def push_fec(self, block, n): 191 | """ 192 | Push a new FEC block into the file 193 | 194 | Args: 195 | block (bytes): block contents 196 | n (int): block number 197 | """ 198 | if (len(self.__fec_blocks) <= n): 199 | self.__fec_blocks.extend([None]*(n - len(self.__fec_blocks) + 1)) 200 | if self.__fec_blocks[n] and self.__fec_blocks[n] != block: 201 | print('[File service] Overwriting FEC block {} in {} with a block having different contents'.format(n, self.path)) 202 | self.__fec_blocks[n] = block 203 | 204 | @property 205 | def maybe_reconstructable(self): 206 | """ 207 | Indicates whether a reconstruction seems feasible 208 | """ 209 | blocks_received = self.blocks - self.__blocks.count(None) 210 | if self.fec: 211 | blocks_received += len(self.__fec_blocks) - self.__fec_blocks.count(None) 212 | return blocks_received >= self.blocks 213 | 214 | @property 215 | def reconstructable(self): 216 | """ 217 | Indicates whether a reconstruction is possible 218 | """ 219 | return self.__blocks.count(None) == 0 220 | 221 | def reconstruct(self): 222 | """ 223 | Try to reconstruct the file 224 | 225 | Returns the file contents (as bytes) if successful, None if not successful 226 | """ 227 | contents = [] 228 | if self.fec and self.fec.startswith('ldpc:'): 229 | if not self.__fec_matrix: 230 | fec_params = dict([tuple(kvp.split('=')) for kvp in self.fec[5:].split(',')]) 231 | self.__fec_matrix = self.__fec_init_matrix(fec_params) 232 | blocks_remain = self.__blocks.count(None) 233 | fec_indices = [i for i in range(len(self.__fec_blocks)) if self.__fec_blocks[i]] 234 | while blocks_remain > 0: 235 | blocks_repaired = 0 236 | for fec_index in fec_indices[:]: 237 | row = self.__fec_matrix[fec_index] 238 | missing_indices = [i for i in row if not self.__blocks[i]] 239 | if len(missing_indices) > 1: 240 | continue 241 | fec_indices.remove(fec_index) 242 | if len(missing_indices) == 0: 243 | continue 244 | missing_index = missing_indices[0] 245 | accum = self.__fec_blocks[fec_index] 246 | for index in row: 247 | if index != missing_index: 248 | unpadded_size = min(self.block_size, self.size - self.block_size * index) 249 | symbol = self.__blocks[index][:unpadded_size] + b'\xff' * (self.block_size - unpadded_size) 250 | accum = bytes([accum[i] ^ symbol[i] for i in range(len(accum))]) 251 | missing_unpadded_size = min(self.block_size, self.size - self.block_size * missing_index) 252 | self.__blocks[missing_index] = accum[:missing_unpadded_size] 253 | blocks_repaired += 1 254 | blocks_remain -= 1 255 | if blocks_repaired == 0: 256 | print('Unable to reconstruct file {}'.format(self.path)) 257 | return 258 | contents = bytes().join(self.__blocks) 259 | else: # No (supported) FEC 260 | if None in self.__blocks: 261 | print('Some blocks are missing. Cannot reconstruct file {}'.format(self.path)) 262 | return 263 | contents = bytes().join(self.__blocks) 264 | 265 | if len(contents) != self.size: 266 | print('File length mismatch. Cannot reconstruct file {}'.format(self.path)) 267 | return 268 | 269 | h = hashlib.sha256() 270 | h.update(contents) 271 | if h.hexdigest() != self.hash: 272 | print('File sha256sum mismatch. Cannot reconstruct file {}'.format(self.path)) 273 | return 274 | 275 | return contents 276 | 277 | def __fec_init_matrix(self, params): 278 | """ 279 | Build a matrix for FEC 280 | 281 | Args: 282 | params (dict): Parameters used to encode the data 283 | """ 284 | k = int(params['k']) 285 | n = int(params['n']) 286 | n1 = int(params['N1']) 287 | seed = int(params['seed']) if 'seed' in params else 1 288 | prng = self.__fec_prng(seed) 289 | p_tbl = [ p % (n - k) for p in range(k * n1)] 290 | matrix = [[] for _ in range(n - k)] 291 | t = 0 292 | for col in range(k): 293 | for h in range(n1): 294 | i = t 295 | while i < k * n1 and col in matrix[p_tbl[i]]: 296 | i += 1 297 | if i >= k * n1: 298 | while True: 299 | row = next(prng) % (n - k) 300 | if col not in matrix[row]: 301 | break 302 | matrix[row].append(col) 303 | else: 304 | while True: 305 | p = next(prng) % (k * n1 - t) + t 306 | if col not in matrix[p_tbl[p]]: 307 | break 308 | matrix[p_tbl[p]].append(col) 309 | p_tbl[p] = p_tbl[t] 310 | t += 1 311 | for row in range(n - k): 312 | degree = len(matrix[row]) 313 | if degree == 0: 314 | col = next(prng) % k 315 | matrix[row].append(col) 316 | if degree <= 1: 317 | while True: 318 | col = next(prng) % k 319 | if col not in matrix[row]: 320 | break 321 | matrix[row].append(col) 322 | return matrix 323 | 324 | def __fec_prng(self, seed): 325 | """ 326 | Generate pseudo random numbers 327 | 328 | Implementation of the Park-Miller random number generator 329 | 330 | Args: 331 | seed (int): Seed 332 | """ 333 | value = seed 334 | while True: 335 | value = (7**5 * value) % (2**31 - 1) 336 | yield value 337 | -------------------------------------------------------------------------------- /LICENSE: -------------------------------------------------------------------------------- 1 | GNU GENERAL PUBLIC LICENSE 2 | Version 3, 29 June 2007 3 | 4 | Copyright (C) 2007 Free Software Foundation, Inc. 5 | Everyone is permitted to copy and distribute verbatim copies 6 | of this license document, but changing it is not allowed. 7 | 8 | Preamble 9 | 10 | The GNU General Public License is a free, copyleft license for 11 | software and other kinds of works. 12 | 13 | The licenses for most software and other practical works are designed 14 | to take away your freedom to share and change the works. By contrast, 15 | the GNU General Public License is intended to guarantee your freedom to 16 | share and change all versions of a program--to make sure it remains free 17 | software for all its users. We, the Free Software Foundation, use the 18 | GNU General Public License for most of our software; it applies also to 19 | any other work released this way by its authors. You can apply it to 20 | your programs, too. 21 | 22 | When we speak of free software, we are referring to freedom, not 23 | price. Our General Public Licenses are designed to make sure that you 24 | have the freedom to distribute copies of free software (and charge for 25 | them if you wish), that you receive source code or can get it if you 26 | want it, that you can change the software or use pieces of it in new 27 | free programs, and that you know you can do these things. 28 | 29 | To protect your rights, we need to prevent others from denying you 30 | these rights or asking you to surrender the rights. Therefore, you have 31 | certain responsibilities if you distribute copies of the software, or if 32 | you modify it: responsibilities to respect the freedom of others. 33 | 34 | For example, if you distribute copies of such a program, whether 35 | gratis or for a fee, you must pass on to the recipients the same 36 | freedoms that you received. You must make sure that they, too, receive 37 | or can get the source code. And you must show them these terms so they 38 | know their rights. 39 | 40 | Developers that use the GNU GPL protect your rights with two steps: 41 | (1) assert copyright on the software, and (2) offer you this License 42 | giving you legal permission to copy, distribute and/or modify it. 43 | 44 | For the developers' and authors' protection, the GPL clearly explains 45 | that there is no warranty for this free software. For both users' and 46 | authors' sake, the GPL requires that modified versions be marked as 47 | changed, so that their problems will not be attributed erroneously to 48 | authors of previous versions. 49 | 50 | Some devices are designed to deny users access to install or run 51 | modified versions of the software inside them, although the manufacturer 52 | can do so. This is fundamentally incompatible with the aim of 53 | protecting users' freedom to change the software. The systematic 54 | pattern of such abuse occurs in the area of products for individuals to 55 | use, which is precisely where it is most unacceptable. Therefore, we 56 | have designed this version of the GPL to prohibit the practice for those 57 | products. If such problems arise substantially in other domains, we 58 | stand ready to extend this provision to those domains in future versions 59 | of the GPL, as needed to protect the freedom of users. 60 | 61 | Finally, every program is threatened constantly by software patents. 62 | States should not allow patents to restrict development and use of 63 | software on general-purpose computers, but in those that do, we wish to 64 | avoid the special danger that patents applied to a free program could 65 | make it effectively proprietary. To prevent this, the GPL assures that 66 | patents cannot be used to render the program non-free. 67 | 68 | The precise terms and conditions for copying, distribution and 69 | modification follow. 70 | 71 | TERMS AND CONDITIONS 72 | 73 | 0. Definitions. 74 | 75 | "This License" refers to version 3 of the GNU General Public License. 76 | 77 | "Copyright" also means copyright-like laws that apply to other kinds of 78 | works, such as semiconductor masks. 79 | 80 | "The Program" refers to any copyrightable work licensed under this 81 | License. Each licensee is addressed as "you". "Licensees" and 82 | "recipients" may be individuals or organizations. 83 | 84 | To "modify" a work means to copy from or adapt all or part of the work 85 | in a fashion requiring copyright permission, other than the making of an 86 | exact copy. The resulting work is called a "modified version" of the 87 | earlier work or a work "based on" the earlier work. 88 | 89 | A "covered work" means either the unmodified Program or a work based 90 | on the Program. 91 | 92 | To "propagate" a work means to do anything with it that, without 93 | permission, would make you directly or secondarily liable for 94 | infringement under applicable copyright law, except executing it on a 95 | computer or modifying a private copy. Propagation includes copying, 96 | distribution (with or without modification), making available to the 97 | public, and in some countries other activities as well. 98 | 99 | To "convey" a work means any kind of propagation that enables other 100 | parties to make or receive copies. Mere interaction with a user through 101 | a computer network, with no transfer of a copy, is not conveying. 102 | 103 | An interactive user interface displays "Appropriate Legal Notices" 104 | to the extent that it includes a convenient and prominently visible 105 | feature that (1) displays an appropriate copyright notice, and (2) 106 | tells the user that there is no warranty for the work (except to the 107 | extent that warranties are provided), that licensees may convey the 108 | work under this License, and how to view a copy of this License. If 109 | the interface presents a list of user commands or options, such as a 110 | menu, a prominent item in the list meets this criterion. 111 | 112 | 1. Source Code. 113 | 114 | The "source code" for a work means the preferred form of the work 115 | for making modifications to it. "Object code" means any non-source 116 | form of a work. 117 | 118 | A "Standard Interface" means an interface that either is an official 119 | standard defined by a recognized standards body, or, in the case of 120 | interfaces specified for a particular programming language, one that 121 | is widely used among developers working in that language. 122 | 123 | The "System Libraries" of an executable work include anything, other 124 | than the work as a whole, that (a) is included in the normal form of 125 | packaging a Major Component, but which is not part of that Major 126 | Component, and (b) serves only to enable use of the work with that 127 | Major Component, or to implement a Standard Interface for which an 128 | implementation is available to the public in source code form. A 129 | "Major Component", in this context, means a major essential component 130 | (kernel, window system, and so on) of the specific operating system 131 | (if any) on which the executable work runs, or a compiler used to 132 | produce the work, or an object code interpreter used to run it. 133 | 134 | The "Corresponding Source" for a work in object code form means all 135 | the source code needed to generate, install, and (for an executable 136 | work) run the object code and to modify the work, including scripts to 137 | control those activities. However, it does not include the work's 138 | System Libraries, or general-purpose tools or generally available free 139 | programs which are used unmodified in performing those activities but 140 | which are not part of the work. For example, Corresponding Source 141 | includes interface definition files associated with source files for 142 | the work, and the source code for shared libraries and dynamically 143 | linked subprograms that the work is specifically designed to require, 144 | such as by intimate data communication or control flow between those 145 | subprograms and other parts of the work. 146 | 147 | The Corresponding Source need not include anything that users 148 | can regenerate automatically from other parts of the Corresponding 149 | Source. 150 | 151 | The Corresponding Source for a work in source code form is that 152 | same work. 153 | 154 | 2. Basic Permissions. 155 | 156 | All rights granted under this License are granted for the term of 157 | copyright on the Program, and are irrevocable provided the stated 158 | conditions are met. This License explicitly affirms your unlimited 159 | permission to run the unmodified Program. The output from running a 160 | covered work is covered by this License only if the output, given its 161 | content, constitutes a covered work. This License acknowledges your 162 | rights of fair use or other equivalent, as provided by copyright law. 163 | 164 | You may make, run and propagate covered works that you do not 165 | convey, without conditions so long as your license otherwise remains 166 | in force. You may convey covered works to others for the sole purpose 167 | of having them make modifications exclusively for you, or provide you 168 | with facilities for running those works, provided that you comply with 169 | the terms of this License in conveying all material for which you do 170 | not control copyright. Those thus making or running the covered works 171 | for you must do so exclusively on your behalf, under your direction 172 | and control, on terms that prohibit them from making any copies of 173 | your copyrighted material outside their relationship with you. 174 | 175 | Conveying under any other circumstances is permitted solely under 176 | the conditions stated below. Sublicensing is not allowed; section 10 177 | makes it unnecessary. 178 | 179 | 3. Protecting Users' Legal Rights From Anti-Circumvention Law. 180 | 181 | No covered work shall be deemed part of an effective technological 182 | measure under any applicable law fulfilling obligations under article 183 | 11 of the WIPO copyright treaty adopted on 20 December 1996, or 184 | similar laws prohibiting or restricting circumvention of such 185 | measures. 186 | 187 | When you convey a covered work, you waive any legal power to forbid 188 | circumvention of technological measures to the extent such circumvention 189 | is effected by exercising rights under this License with respect to 190 | the covered work, and you disclaim any intention to limit operation or 191 | modification of the work as a means of enforcing, against the work's 192 | users, your or third parties' legal rights to forbid circumvention of 193 | technological measures. 194 | 195 | 4. Conveying Verbatim Copies. 196 | 197 | You may convey verbatim copies of the Program's source code as you 198 | receive it, in any medium, provided that you conspicuously and 199 | appropriately publish on each copy an appropriate copyright notice; 200 | keep intact all notices stating that this License and any 201 | non-permissive terms added in accord with section 7 apply to the code; 202 | keep intact all notices of the absence of any warranty; and give all 203 | recipients a copy of this License along with the Program. 204 | 205 | You may charge any price or no price for each copy that you convey, 206 | and you may offer support or warranty protection for a fee. 207 | 208 | 5. Conveying Modified Source Versions. 209 | 210 | You may convey a work based on the Program, or the modifications to 211 | produce it from the Program, in the form of source code under the 212 | terms of section 4, provided that you also meet all of these conditions: 213 | 214 | a) The work must carry prominent notices stating that you modified 215 | it, and giving a relevant date. 216 | 217 | b) The work must carry prominent notices stating that it is 218 | released under this License and any conditions added under section 219 | 7. This requirement modifies the requirement in section 4 to 220 | "keep intact all notices". 221 | 222 | c) You must license the entire work, as a whole, under this 223 | License to anyone who comes into possession of a copy. This 224 | License will therefore apply, along with any applicable section 7 225 | additional terms, to the whole of the work, and all its parts, 226 | regardless of how they are packaged. This License gives no 227 | permission to license the work in any other way, but it does not 228 | invalidate such permission if you have separately received it. 229 | 230 | d) If the work has interactive user interfaces, each must display 231 | Appropriate Legal Notices; however, if the Program has interactive 232 | interfaces that do not display Appropriate Legal Notices, your 233 | work need not make them do so. 234 | 235 | A compilation of a covered work with other separate and independent 236 | works, which are not by their nature extensions of the covered work, 237 | and which are not combined with it such as to form a larger program, 238 | in or on a volume of a storage or distribution medium, is called an 239 | "aggregate" if the compilation and its resulting copyright are not 240 | used to limit the access or legal rights of the compilation's users 241 | beyond what the individual works permit. Inclusion of a covered work 242 | in an aggregate does not cause this License to apply to the other 243 | parts of the aggregate. 244 | 245 | 6. Conveying Non-Source Forms. 246 | 247 | You may convey a covered work in object code form under the terms 248 | of sections 4 and 5, provided that you also convey the 249 | machine-readable Corresponding Source under the terms of this License, 250 | in one of these ways: 251 | 252 | a) Convey the object code in, or embodied in, a physical product 253 | (including a physical distribution medium), accompanied by the 254 | Corresponding Source fixed on a durable physical medium 255 | customarily used for software interchange. 256 | 257 | b) Convey the object code in, or embodied in, a physical product 258 | (including a physical distribution medium), accompanied by a 259 | written offer, valid for at least three years and valid for as 260 | long as you offer spare parts or customer support for that product 261 | model, to give anyone who possesses the object code either (1) a 262 | copy of the Corresponding Source for all the software in the 263 | product that is covered by this License, on a durable physical 264 | medium customarily used for software interchange, for a price no 265 | more than your reasonable cost of physically performing this 266 | conveying of source, or (2) access to copy the 267 | Corresponding Source from a network server at no charge. 268 | 269 | c) Convey individual copies of the object code with a copy of the 270 | written offer to provide the Corresponding Source. This 271 | alternative is allowed only occasionally and noncommercially, and 272 | only if you received the object code with such an offer, in accord 273 | with subsection 6b. 274 | 275 | d) Convey the object code by offering access from a designated 276 | place (gratis or for a charge), and offer equivalent access to the 277 | Corresponding Source in the same way through the same place at no 278 | further charge. You need not require recipients to copy the 279 | Corresponding Source along with the object code. If the place to 280 | copy the object code is a network server, the Corresponding Source 281 | may be on a different server (operated by you or a third party) 282 | that supports equivalent copying facilities, provided you maintain 283 | clear directions next to the object code saying where to find the 284 | Corresponding Source. Regardless of what server hosts the 285 | Corresponding Source, you remain obligated to ensure that it is 286 | available for as long as needed to satisfy these requirements. 287 | 288 | e) Convey the object code using peer-to-peer transmission, provided 289 | you inform other peers where the object code and Corresponding 290 | Source of the work are being offered to the general public at no 291 | charge under subsection 6d. 292 | 293 | A separable portion of the object code, whose source code is excluded 294 | from the Corresponding Source as a System Library, need not be 295 | included in conveying the object code work. 296 | 297 | A "User Product" is either (1) a "consumer product", which means any 298 | tangible personal property which is normally used for personal, family, 299 | or household purposes, or (2) anything designed or sold for incorporation 300 | into a dwelling. In determining whether a product is a consumer product, 301 | doubtful cases shall be resolved in favor of coverage. For a particular 302 | product received by a particular user, "normally used" refers to a 303 | typical or common use of that class of product, regardless of the status 304 | of the particular user or of the way in which the particular user 305 | actually uses, or expects or is expected to use, the product. A product 306 | is a consumer product regardless of whether the product has substantial 307 | commercial, industrial or non-consumer uses, unless such uses represent 308 | the only significant mode of use of the product. 309 | 310 | "Installation Information" for a User Product means any methods, 311 | procedures, authorization keys, or other information required to install 312 | and execute modified versions of a covered work in that User Product from 313 | a modified version of its Corresponding Source. The information must 314 | suffice to ensure that the continued functioning of the modified object 315 | code is in no case prevented or interfered with solely because 316 | modification has been made. 317 | 318 | If you convey an object code work under this section in, or with, or 319 | specifically for use in, a User Product, and the conveying occurs as 320 | part of a transaction in which the right of possession and use of the 321 | User Product is transferred to the recipient in perpetuity or for a 322 | fixed term (regardless of how the transaction is characterized), the 323 | Corresponding Source conveyed under this section must be accompanied 324 | by the Installation Information. But this requirement does not apply 325 | if neither you nor any third party retains the ability to install 326 | modified object code on the User Product (for example, the work has 327 | been installed in ROM). 328 | 329 | The requirement to provide Installation Information does not include a 330 | requirement to continue to provide support service, warranty, or updates 331 | for a work that has been modified or installed by the recipient, or for 332 | the User Product in which it has been modified or installed. Access to a 333 | network may be denied when the modification itself materially and 334 | adversely affects the operation of the network or violates the rules and 335 | protocols for communication across the network. 336 | 337 | Corresponding Source conveyed, and Installation Information provided, 338 | in accord with this section must be in a format that is publicly 339 | documented (and with an implementation available to the public in 340 | source code form), and must require no special password or key for 341 | unpacking, reading or copying. 342 | 343 | 7. Additional Terms. 344 | 345 | "Additional permissions" are terms that supplement the terms of this 346 | License by making exceptions from one or more of its conditions. 347 | Additional permissions that are applicable to the entire Program shall 348 | be treated as though they were included in this License, to the extent 349 | that they are valid under applicable law. If additional permissions 350 | apply only to part of the Program, that part may be used separately 351 | under those permissions, but the entire Program remains governed by 352 | this License without regard to the additional permissions. 353 | 354 | When you convey a copy of a covered work, you may at your option 355 | remove any additional permissions from that copy, or from any part of 356 | it. (Additional permissions may be written to require their own 357 | removal in certain cases when you modify the work.) You may place 358 | additional permissions on material, added by you to a covered work, 359 | for which you have or can give appropriate copyright permission. 360 | 361 | Notwithstanding any other provision of this License, for material you 362 | add to a covered work, you may (if authorized by the copyright holders of 363 | that material) supplement the terms of this License with terms: 364 | 365 | a) Disclaiming warranty or limiting liability differently from the 366 | terms of sections 15 and 16 of this License; or 367 | 368 | b) Requiring preservation of specified reasonable legal notices or 369 | author attributions in that material or in the Appropriate Legal 370 | Notices displayed by works containing it; or 371 | 372 | c) Prohibiting misrepresentation of the origin of that material, or 373 | requiring that modified versions of such material be marked in 374 | reasonable ways as different from the original version; or 375 | 376 | d) Limiting the use for publicity purposes of names of licensors or 377 | authors of the material; or 378 | 379 | e) Declining to grant rights under trademark law for use of some 380 | trade names, trademarks, or service marks; or 381 | 382 | f) Requiring indemnification of licensors and authors of that 383 | material by anyone who conveys the material (or modified versions of 384 | it) with contractual assumptions of liability to the recipient, for 385 | any liability that these contractual assumptions directly impose on 386 | those licensors and authors. 387 | 388 | All other non-permissive additional terms are considered "further 389 | restrictions" within the meaning of section 10. If the Program as you 390 | received it, or any part of it, contains a notice stating that it is 391 | governed by this License along with a term that is a further 392 | restriction, you may remove that term. If a license document contains 393 | a further restriction but permits relicensing or conveying under this 394 | License, you may add to a covered work material governed by the terms 395 | of that license document, provided that the further restriction does 396 | not survive such relicensing or conveying. 397 | 398 | If you add terms to a covered work in accord with this section, you 399 | must place, in the relevant source files, a statement of the 400 | additional terms that apply to those files, or a notice indicating 401 | where to find the applicable terms. 402 | 403 | Additional terms, permissive or non-permissive, may be stated in the 404 | form of a separately written license, or stated as exceptions; 405 | the above requirements apply either way. 406 | 407 | 8. Termination. 408 | 409 | You may not propagate or modify a covered work except as expressly 410 | provided under this License. Any attempt otherwise to propagate or 411 | modify it is void, and will automatically terminate your rights under 412 | this License (including any patent licenses granted under the third 413 | paragraph of section 11). 414 | 415 | However, if you cease all violation of this License, then your 416 | license from a particular copyright holder is reinstated (a) 417 | provisionally, unless and until the copyright holder explicitly and 418 | finally terminates your license, and (b) permanently, if the copyright 419 | holder fails to notify you of the violation by some reasonable means 420 | prior to 60 days after the cessation. 421 | 422 | Moreover, your license from a particular copyright holder is 423 | reinstated permanently if the copyright holder notifies you of the 424 | violation by some reasonable means, this is the first time you have 425 | received notice of violation of this License (for any work) from that 426 | copyright holder, and you cure the violation prior to 30 days after 427 | your receipt of the notice. 428 | 429 | Termination of your rights under this section does not terminate the 430 | licenses of parties who have received copies or rights from you under 431 | this License. If your rights have been terminated and not permanently 432 | reinstated, you do not qualify to receive new licenses for the same 433 | material under section 10. 434 | 435 | 9. Acceptance Not Required for Having Copies. 436 | 437 | You are not required to accept this License in order to receive or 438 | run a copy of the Program. Ancillary propagation of a covered work 439 | occurring solely as a consequence of using peer-to-peer transmission 440 | to receive a copy likewise does not require acceptance. However, 441 | nothing other than this License grants you permission to propagate or 442 | modify any covered work. These actions infringe copyright if you do 443 | not accept this License. Therefore, by modifying or propagating a 444 | covered work, you indicate your acceptance of this License to do so. 445 | 446 | 10. Automatic Licensing of Downstream Recipients. 447 | 448 | Each time you convey a covered work, the recipient automatically 449 | receives a license from the original licensors, to run, modify and 450 | propagate that work, subject to this License. You are not responsible 451 | for enforcing compliance by third parties with this License. 452 | 453 | An "entity transaction" is a transaction transferring control of an 454 | organization, or substantially all assets of one, or subdividing an 455 | organization, or merging organizations. If propagation of a covered 456 | work results from an entity transaction, each party to that 457 | transaction who receives a copy of the work also receives whatever 458 | licenses to the work the party's predecessor in interest had or could 459 | give under the previous paragraph, plus a right to possession of the 460 | Corresponding Source of the work from the predecessor in interest, if 461 | the predecessor has it or can get it with reasonable efforts. 462 | 463 | You may not impose any further restrictions on the exercise of the 464 | rights granted or affirmed under this License. For example, you may 465 | not impose a license fee, royalty, or other charge for exercise of 466 | rights granted under this License, and you may not initiate litigation 467 | (including a cross-claim or counterclaim in a lawsuit) alleging that 468 | any patent claim is infringed by making, using, selling, offering for 469 | sale, or importing the Program or any portion of it. 470 | 471 | 11. Patents. 472 | 473 | A "contributor" is a copyright holder who authorizes use under this 474 | License of the Program or a work on which the Program is based. The 475 | work thus licensed is called the contributor's "contributor version". 476 | 477 | A contributor's "essential patent claims" are all patent claims 478 | owned or controlled by the contributor, whether already acquired or 479 | hereafter acquired, that would be infringed by some manner, permitted 480 | by this License, of making, using, or selling its contributor version, 481 | but do not include claims that would be infringed only as a 482 | consequence of further modification of the contributor version. For 483 | purposes of this definition, "control" includes the right to grant 484 | patent sublicenses in a manner consistent with the requirements of 485 | this License. 486 | 487 | Each contributor grants you a non-exclusive, worldwide, royalty-free 488 | patent license under the contributor's essential patent claims, to 489 | make, use, sell, offer for sale, import and otherwise run, modify and 490 | propagate the contents of its contributor version. 491 | 492 | In the following three paragraphs, a "patent license" is any express 493 | agreement or commitment, however denominated, not to enforce a patent 494 | (such as an express permission to practice a patent or covenant not to 495 | sue for patent infringement). To "grant" such a patent license to a 496 | party means to make such an agreement or commitment not to enforce a 497 | patent against the party. 498 | 499 | If you convey a covered work, knowingly relying on a patent license, 500 | and the Corresponding Source of the work is not available for anyone 501 | to copy, free of charge and under the terms of this License, through a 502 | publicly available network server or other readily accessible means, 503 | then you must either (1) cause the Corresponding Source to be so 504 | available, or (2) arrange to deprive yourself of the benefit of the 505 | patent license for this particular work, or (3) arrange, in a manner 506 | consistent with the requirements of this License, to extend the patent 507 | license to downstream recipients. "Knowingly relying" means you have 508 | actual knowledge that, but for the patent license, your conveying the 509 | covered work in a country, or your recipient's use of the covered work 510 | in a country, would infringe one or more identifiable patents in that 511 | country that you have reason to believe are valid. 512 | 513 | If, pursuant to or in connection with a single transaction or 514 | arrangement, you convey, or propagate by procuring conveyance of, a 515 | covered work, and grant a patent license to some of the parties 516 | receiving the covered work authorizing them to use, propagate, modify 517 | or convey a specific copy of the covered work, then the patent license 518 | you grant is automatically extended to all recipients of the covered 519 | work and works based on it. 520 | 521 | A patent license is "discriminatory" if it does not include within 522 | the scope of its coverage, prohibits the exercise of, or is 523 | conditioned on the non-exercise of one or more of the rights that are 524 | specifically granted under this License. You may not convey a covered 525 | work if you are a party to an arrangement with a third party that is 526 | in the business of distributing software, under which you make payment 527 | to the third party based on the extent of your activity of conveying 528 | the work, and under which the third party grants, to any of the 529 | parties who would receive the covered work from you, a discriminatory 530 | patent license (a) in connection with copies of the covered work 531 | conveyed by you (or copies made from those copies), or (b) primarily 532 | for and in connection with specific products or compilations that 533 | contain the covered work, unless you entered into that arrangement, 534 | or that patent license was granted, prior to 28 March 2007. 535 | 536 | Nothing in this License shall be construed as excluding or limiting 537 | any implied license or other defenses to infringement that may 538 | otherwise be available to you under applicable patent law. 539 | 540 | 12. No Surrender of Others' Freedom. 541 | 542 | If conditions are imposed on you (whether by court order, agreement or 543 | otherwise) that contradict the conditions of this License, they do not 544 | excuse you from the conditions of this License. If you cannot convey a 545 | covered work so as to satisfy simultaneously your obligations under this 546 | License and any other pertinent obligations, then as a consequence you may 547 | not convey it at all. For example, if you agree to terms that obligate you 548 | to collect a royalty for further conveying from those to whom you convey 549 | the Program, the only way you could satisfy both those terms and this 550 | License would be to refrain entirely from conveying the Program. 551 | 552 | 13. Use with the GNU Affero General Public License. 553 | 554 | Notwithstanding any other provision of this License, you have 555 | permission to link or combine any covered work with a work licensed 556 | under version 3 of the GNU Affero General Public License into a single 557 | combined work, and to convey the resulting work. The terms of this 558 | License will continue to apply to the part which is the covered work, 559 | but the special requirements of the GNU Affero General Public License, 560 | section 13, concerning interaction through a network will apply to the 561 | combination as such. 562 | 563 | 14. Revised Versions of this License. 564 | 565 | The Free Software Foundation may publish revised and/or new versions of 566 | the GNU General Public License from time to time. Such new versions will 567 | be similar in spirit to the present version, but may differ in detail to 568 | address new problems or concerns. 569 | 570 | Each version is given a distinguishing version number. If the 571 | Program specifies that a certain numbered version of the GNU General 572 | Public License "or any later version" applies to it, you have the 573 | option of following the terms and conditions either of that numbered 574 | version or of any later version published by the Free Software 575 | Foundation. If the Program does not specify a version number of the 576 | GNU General Public License, you may choose any version ever published 577 | by the Free Software Foundation. 578 | 579 | If the Program specifies that a proxy can decide which future 580 | versions of the GNU General Public License can be used, that proxy's 581 | public statement of acceptance of a version permanently authorizes you 582 | to choose that version for the Program. 583 | 584 | Later license versions may give you additional or different 585 | permissions. However, no additional obligations are imposed on any 586 | author or copyright holder as a result of your choosing to follow a 587 | later version. 588 | 589 | 15. Disclaimer of Warranty. 590 | 591 | THERE IS NO WARRANTY FOR THE PROGRAM, TO THE EXTENT PERMITTED BY 592 | APPLICABLE LAW. EXCEPT WHEN OTHERWISE STATED IN WRITING THE COPYRIGHT 593 | HOLDERS AND/OR OTHER PARTIES PROVIDE THE PROGRAM "AS IS" WITHOUT WARRANTY 594 | OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING, BUT NOT LIMITED TO, 595 | THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 596 | PURPOSE. THE ENTIRE RISK AS TO THE QUALITY AND PERFORMANCE OF THE PROGRAM 597 | IS WITH YOU. SHOULD THE PROGRAM PROVE DEFECTIVE, YOU ASSUME THE COST OF 598 | ALL NECESSARY SERVICING, REPAIR OR CORRECTION. 599 | 600 | 16. Limitation of Liability. 601 | 602 | IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN WRITING 603 | WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MODIFIES AND/OR CONVEYS 604 | THE PROGRAM AS PERMITTED ABOVE, BE LIABLE TO YOU FOR DAMAGES, INCLUDING ANY 605 | GENERAL, SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING OUT OF THE 606 | USE OR INABILITY TO USE THE PROGRAM (INCLUDING BUT NOT LIMITED TO LOSS OF 607 | DATA OR DATA BEING RENDERED INACCURATE OR LOSSES SUSTAINED BY YOU OR THIRD 608 | PARTIES OR A FAILURE OF THE PROGRAM TO OPERATE WITH ANY OTHER PROGRAMS), 609 | EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE POSSIBILITY OF 610 | SUCH DAMAGES. 611 | 612 | 17. Interpretation of Sections 15 and 16. 613 | 614 | If the disclaimer of warranty and limitation of liability provided 615 | above cannot be given local legal effect according to their terms, 616 | reviewing courts shall apply local law that most closely approximates 617 | an absolute waiver of all civil liability in connection with the 618 | Program, unless a warranty or assumption of liability accompanies a 619 | copy of the Program in return for a fee. 620 | 621 | END OF TERMS AND CONDITIONS 622 | 623 | How to Apply These Terms to Your New Programs 624 | 625 | If you develop a new program, and you want it to be of the greatest 626 | possible use to the public, the best way to achieve this is to make it 627 | free software which everyone can redistribute and change under these terms. 628 | 629 | To do so, attach the following notices to the program. It is safest 630 | to attach them to the start of each source file to most effectively 631 | state the exclusion of warranty; and each file should have at least 632 | the "copyright" line and a pointer to where the full notice is found. 633 | 634 | {one line to give the program's name and a brief idea of what it does.} 635 | Copyright (C) {year} {name of author} 636 | 637 | This program is free software: you can redistribute it and/or modify 638 | it under the terms of the GNU General Public License as published by 639 | the Free Software Foundation, either version 3 of the License, or 640 | (at your option) any later version. 641 | 642 | This program is distributed in the hope that it will be useful, 643 | but WITHOUT ANY WARRANTY; without even the implied warranty of 644 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 645 | GNU General Public License for more details. 646 | 647 | You should have received a copy of the GNU General Public License 648 | along with this program. If not, see . 649 | 650 | Also add information on how to contact you by electronic and paper mail. 651 | 652 | If the program does terminal interaction, make it output a short 653 | notice like this when it starts in an interactive mode: 654 | 655 | {project} Copyright (C) {year} {fullname} 656 | This program comes with ABSOLUTELY NO WARRANTY; for details type `show w'. 657 | This is free software, and you are welcome to redistribute it 658 | under certain conditions; type `show c' for details. 659 | 660 | The hypothetical commands `show w' and `show c' should show the appropriate 661 | parts of the General Public License. Of course, your program's commands 662 | might be different; for a GUI interface, you would use an "about box". 663 | 664 | You should also get your employer (if you work as a programmer) or school, 665 | if any, to sign a "copyright disclaimer" for the program, if necessary. 666 | For more information on this, and how to apply and follow the GNU GPL, see 667 | . 668 | 669 | The GNU General Public License does not permit incorporating your program 670 | into proprietary programs. If your program is a subroutine library, you 671 | may consider it more useful to permit linking proprietary applications with 672 | the library. If this is what you want to do, use the GNU Lesser General 673 | Public License instead of this License. But first, please read 674 | . 675 | --------------------------------------------------------------------------------