commit ef0bff2ff3c14934a6cd056d8a9d03151741c675 Author: Nick Mathewson nickm@torproject.org Date: Tue Mar 15 17:23:19 2011 -0400

Describe optimistic data protocol. (Text from Ian) --- tor-spec.txt | 18 ++++++++++++++++-- 1 files changed, 16 insertions(+), 2 deletions(-)

diff --git a/tor-spec.txt b/tor-spec.txt index e889431..cb4c70d 100644 --- a/tor-spec.txt +++ b/tor-spec.txt @@ -797,11 +797,25 @@ see tor-design.pdf. their own cached entries after a fixed interval. This prevents certain attacks.]

- The OP waits for a RELAY_CONNECTED cell before sending any data. Once a connection has been established, the OP and exit node package stream data in RELAY_DATA cells, and upon receiving such cells, echo their contents to the corresponding TCP stream. - RELAY_DATA cells sent to unrecognized streams are dropped. + + If the exit node does not support optimistic data (i.e. its + version number is before 0.2.3.1-alpha), then the OP MUST wait + for a RELAY_CONNECTED cell before sending any data. If the exit + node supports optimistic data (i.e. its version number is + 0.2.3.1-alpha or later), then the OP MAY send RELAY_DATA cells + immediately after sending the RELAY_BEGIN cell (and before + receiving either a RELAY_CONNECTED or RELAY_END cell). + + RELAY_DATA cells sent to unrecognized streams are dropped. If + the exit node supports optimistic data, then RELAY_DATA cells it + receives on streams which have seen RELAY_BEGIN but have not yet + been replied to with a RELAY_CONNECTED or RELAY_END are queued. + If the stream creation succeeds with a RELAY_CONNECTED, the queue + is processed immediately afterwards; if the stream creation fails + with a RELAY_END, the contents of the queue are deleted.

Relay RELAY_DROP cells are long-range dummies; upon receiving such a cell, the OR or OP must drop it.