129 lines
3.7 KiB
Python
Executable File
129 lines
3.7 KiB
Python
Executable File
import struct
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import time
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import FPE
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class Packet:
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# Constants
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RESOURCE = 0x00;
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ANNOUNCE = 0x01;
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LINKREQUEST = 0x02;
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PROOF = 0x03;
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types = [RESOURCE, ANNOUNCE, LINKREQUEST, PROOF]
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HEADER_1 = 0x00; # Normal header format
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HEADER_2 = 0x01; # Header format used for link packets in transport
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HEADER_3 = 0x02; # Reserved
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HEADER_4 = 0x03; # Reserved
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header_types = [HEADER_1, HEADER_2, HEADER_3, HEADER_4]
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def __init__(self, destination, data, packet_type = RESOURCE, transport_type = FPE.Transport.BROADCAST, header_type = HEADER_1, transport_id = None):
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if destination != None:
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if transport_type == None:
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transport_type = FPE.Transport.BROADCAST
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self.header_type = header_type
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self.packet_type = packet_type
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self.transport_type = transport_type
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self.hops = 0;
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self.destination = destination
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self.transport_id = transport_id
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self.data = data
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self.flags = self.getPackedFlags()
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self.MTU = self.destination.MTU
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self.raw = None
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self.packed = False
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self.sent = False
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self.fromPacked = False
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else:
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self.raw = data
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self.packed = True
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self.fromPacked = True
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self.sent_at = None
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self.packet_hash = None
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def getPackedFlags(self):
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packed_flags = (self.header_type << 6) | (self.transport_type << 4) | (self.destination.type << 2) | self.packet_type
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return packed_flags
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def pack(self):
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self.header = ""
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self.header += struct.pack("!B", self.flags)
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self.header += struct.pack("!B", self.hops)
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if self.header_type == Packet.HEADER_2:
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if t_destination != None:
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self.header += self.t_destination
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else:
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raise IOError("Packet with header type 2 must have a transport ID")
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self.header += self.destination.hash
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if self.packet_type != Packet.ANNOUNCE:
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self.ciphertext = self.destination.encrypt(self.data)
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else:
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self.ciphertext = self.data
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self.raw = self.header + self.ciphertext
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if len(self.raw) > self.MTU:
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raise IOError("Packet size of "+str(len(self.raw))+" exceeds MTU of "+str(self.MTU)+" bytes")
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self.packed = True
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def unpack(self):
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self.flags = ord(self.raw[0])
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self.hops = ord(self.raw[1])
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self.header_type = (self.flags & 0b11000000) >> 6
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self.transport_type = (self.flags & 0b00110000) >> 4
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self.destination_type = (self.flags & 0b00001100) >> 2
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self.packet_type = (self.flags & 0b00000011)
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if self.header_type == Packet.HEADER_2:
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self.transport_id = self.raw[2:12]
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self.destination_hash = self.raw[12:22]
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self.data = self.raw[22:]
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else:
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self.transport_id = None
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self.destination_hash = self.raw[2:12]
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self.data = self.raw[12:]
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self.packed = False
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def send(self):
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if not self.sent:
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self.pack()
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FPE.log("Size: "+str(len(self.raw))+" header is "+str(len(self.header))+" payload is "+str(len(self.ciphertext)), FPE.LOG_DEBUG)
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FPE.Transport.outbound(self.raw)
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self.packet_hash = FPE.Identity.fullHash(self.raw)
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self.sent_at = time.time()
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self.sent = True
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else:
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raise IOError("Packet was already sent")
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def resend(self):
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if self.sent:
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Transport.outbound(self.raw)
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else:
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raise IOError("Packet was not sent yet")
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def prove(self, destination):
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if self.fromPacked and self.destination:
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if self.destination.identity and self.destination.identity.prv:
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self.destination.identity.prove(self, destination)
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def validateProofPacket(self, proof_packet):
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return self.validateProof(proof_packet.data)
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def validateProof(self, proof):
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proof_hash = proof[:32]
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signature = proof[32:]
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if proof_hash == self.packet_hash:
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return self.destination.identity.validate(signature, proof_hash)
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else:
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return False
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