diff options
Diffstat (limited to 'tor-spec.txt')
| -rw-r--r-- | tor-spec.txt | 33 |
1 files changed, 21 insertions, 12 deletions
diff --git a/tor-spec.txt b/tor-spec.txt index 3f03890..8dcb564 100644 --- a/tor-spec.txt +++ b/tor-spec.txt @@ -1522,18 +1522,27 @@ see tor-design.pdf. version of Tor if a) they have sent relay cells through that node, and b) they aren't sure whether those cells have been sent on yet.] - When an unrecoverable error occurs along one connection in a - circuit, the nodes on either side of the connection should, if they - are able, act as follows: the node closer to the OP should send a - RELAY_TRUNCATED cell towards the OP; the node farther from the OP - should send a DESTROY cell down the circuit. - - The payload of a DESTROY cell contains a single octet, describing the - reason that the circuit was closed. Similarly, the data of a - RELAY_TRUNCATED cell also contains this single octet "reason" field. When - sending a TRUNCATED or DESTROY cell because of another TRUNCATED or - DESTROY cell, the error code should be propagated. The origin of a circuit - always sets this error code to 0, to avoid leaking its version. + When an unrecoverable error occurs along one connection in a circuit, the + nodes on either side of the connection MAY, if they are able, act as + follows: the node closer to the OP can send a RELAY_TRUNCATED cell towards + the OP or a DESTROY cell to the previous OR. + + An OP, upon receiving a RELAY_TRUNCATED, should send forward a DESTROY cell + in order to entirely teardown the circuit. + + NOTE: + In tor version >= 0.4.5.13, 0.4.6.11 and 0.4.7.9, upon receiving a DESTROY + cell from upstream of the circuit, an OR won't send a RELAY_TRUNCATED to + the OP but instead will send a DESTROY down the circuit in order to signal + every intermediary ORs to stop queuing data on the circuit. Before that, + the delay between the OP receiving the RELAY_TRUNCATED cell and sending a + DESTROY cell upward would create queuing pressure on the intermediary ORs. + + The payload of a DESTROY and RELAY_TRUNCATED cell contains a single octet, + describing the reason that the circuit was closed. The emitter of such cell + should use the right reason found below however it should NEVER be + propagated downward or upward due to potential side channel risk. An OR + receiving a DESTROY should use the DESTROYED reason for its next cell. The error codes are: |