commit a3e2f6cd613404ed74ea483dae8234af8a2b7c3e Author: teor teor@torproject.org Date: Wed Jan 29 22:40:31 2020 +1000

Prop 311: Improve Extra Reachability Checks

And add extra logging when tor would have previously found itself reachable, but the new checks fail.

As suggested by Nick Mathewson.

Part of 24404. --- proposals/311-relay-ipv6-reachability.txt | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/proposals/311-relay-ipv6-reachability.txt b/proposals/311-relay-ipv6-reachability.txt index f34d379..40917f2 100644 --- a/proposals/311-relay-ipv6-reachability.txt +++ b/proposals/311-relay-ipv6-reachability.txt @@ -508,8 +508,15 @@ Ticket: #24404 (by comparing the remote address of the final hop on the circuit, to the local IPv4 and IPv6 ORPort addresses).

- TODO: work out how to efficiently match inbound create cells to test - circuits. + Relays can efficiently match inbound create cells to test circuits by + storing a set of their test circuits' extend cells g^X values, and then + check incoming cells create cells against that set. + + If we make these changes, relays should track whether they are + "maybe reachable" (under the current definition of 'reachable') and + "definitely reachable" (based on the new definition). They should log + different messages depending on whether they are "maybe reachable" but these + new tests fail, or whether they are completely unreachable.

4.4.4. Allowing More Relay IPv6 Extends