commit e226989eb19cdbcfa46c6ef9ec6ed866f453a871 Author: Nick Mathewson nickm@torproject.org Date: Fri Aug 27 10:46:46 2021 -0400

Explain when circuits are torn down, and how they become dirty. --- path-spec.txt | 15 ++++++++++++++- 1 file changed, 14 insertions(+), 1 deletion(-)

diff --git a/path-spec.txt b/path-spec.txt index 65d56c4..235f64b 100644 --- a/path-spec.txt +++ b/path-spec.txt @@ -205,6 +205,11 @@ of their choices. might be supported by a pending or built circuit. For internal circuits, we pick an arbitrary acceptable path, repeating as needed.

+ Clients consider a circuit to become "dirty" as soon as a stream is + attached to it, or some other request is performed over the circuit. + If a circuit has been "dirty" for at least MaxCircuitDirtiness seconds, + new circuits may not be attached to it. + In some cases we can reuse an already established circuit if it's clean; see Section 2.3 (cannibalizing circuits) for details.

@@ -242,8 +247,16 @@ of their choices.

2.1.6. When to tear down circuits

- XXXX + Clients should tear down circuits (in general) only when those circuits + have no streams on them. Additionally, clients should tear-down + stream-less circuits only under one of the following conditions: + + - The circuit has never had a stream attached, and it was created too + long in the past (based on CircuitsAvailableTimeout or + cbtlearntimeout, depending on timeout estimate status).

+ - The circuit is dirty (has had a stream attached), and it has been + dirty for at least MaxCircuitDirtiness.

2.2. Path selection and constraints