114 lines
3.4 KiB
Python
114 lines
3.4 KiB
Python
import nacl
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from msg import RelayNetMsg
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class RelayCell(RelayNetMsg):
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"""All cells (which are sent inside a CircuitCellMsg, and so do not
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need their own circuitid) should be a subclass of this class."""
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class StringCell(RelayCell):
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"""Send an arbitrary string as a cell."""
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def __init__(self, str):
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self.data = str
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def __str__(self):
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return self.data.__str__()
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class CloseCell(RelayCell):
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"""Close the circuit this cell was sent on. It should be sent
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_unencrypted_ (not within an EncryptedCell), and relays that receive
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one should forward it along the adjacent circuit, then close both
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the circuit it was received on and the adjacent one."""
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class VanillaCreatedCircuitCell(RelayCell):
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"""The message for responding to circuit creation in Vanilla Onion
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Routing."""
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def __init__(self, ntor_reply):
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self.ntor_reply = ntor_reply
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class VanillaExtendCircuitCell(RelayCell):
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"""The message for requesting circuit extension in Vanilla Onion
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Routing."""
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def __init__(self, hopaddr, ntor_request):
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self.hopaddr = hopaddr
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self.ntor_request = ntor_request
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class VanillaExtendedCircuitCell(RelayCell):
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"""The message for responding to circuit extension in Vanilla Onion
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Routing."""
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def __init__(self, ntor_reply):
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self.ntor_reply = ntor_reply
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class TelescopingCreatedCircuitCell(RelayCell):
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"""The message for responding to circuit creation in Telescoping Walking
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Onions."""
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def __init__(self, ntor_reply):
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self.ntor_reply = ntor_reply
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class TelescopingExtendCircuitCell(RelayCell):
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"""The message for requesting circuit extension in Telescoping Walking
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Onions."""
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def __init__(self, idx, ntor_request):
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self.idx = idx
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self.ntor_request = ntor_request
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class TelescopingExtendedCircuitCell(RelayCell):
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"""The message for responding to circuit extension in Telescoping Walking
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Onions."""
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def __init__(self, ntor_reply, snip):
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self.ntor_reply = ntor_reply
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self.snip = snip
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class SinglePassCreatedCircuitCell(RelayCell):
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"""The message for responding to circuit creation in Single-Pass Walking
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Onions."""
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def __init__(self, ntor_reply, encrypted_cell):
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self.ntor_reply = ntor_reply
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# The above field is sent in plaintext; the below is an
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# SinglePassCreatedEnc, or None if this is the last layer
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self.enc = encrypted_cell
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class EncryptedCell(RelayCell):
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"""Send a message encrypted with a symmetric key. In this
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implementation, the encryption is not really done. A hash of the
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key is stored with the message so that it can be checked at
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decryption time."""
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def __init__(self, key, msg):
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self.keyhash = nacl.hash.sha256(key)
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self.plaintext = msg
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def decrypt(self, key):
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keyhash = nacl.hash.sha256(key)
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if keyhash != self.keyhash:
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raise ValueError("EncryptedCell key mismatch")
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return self.plaintext
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def size(self):
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# Current Tor actually has no overhead for encryption
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return self.plaintext.size()
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class SinglePassCreatedEnc(EncryptedCell):
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"""The nested encrypted informaion inside a
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SinglePassCreatedCircuitCell. nextlayer is itself a
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SinglePassCreatedCircuitCell."""
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def __init__(self, key, snip, vrf_output, nextlayer):
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super().__init__(key, (snip, vrf_output, nextlayer))
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