commit 42eb1fdc55d7f9ccee872de78cb6a4a4fa603904 Author: teor teor@torproject.org Date: Thu Jul 26 09:52:17 2018 +1000
tor-spec: Generalise "exit" to "end" where appropriate
Closes #26885. --- tor-spec.txt | 35 ++++++++++++++++++++++++----------- 1 file changed, 24 insertions(+), 11 deletions(-)
diff --git a/tor-spec.txt b/tor-spec.txt index 441ccee..4722da5 100644 --- a/tor-spec.txt +++ b/tor-spec.txt @@ -1219,13 +1219,15 @@ see tor-design.pdf. When creating a circuit through the network, the circuit creator (OP) performs the following steps:
- 1. Choose an onion router as an exit node (R_N), such that the onion - router's exit policy includes at least one pending stream that - needs a circuit (if there are any). + 1. Choose an onion router as an end node (R_N): + * N MAY be 1 for non-anonymous directory mirror, introduction point, + or service rendezvous connections. + * N SHOULD be 3 or more for anonymous connections. + Some end nodes accept streams (see 6.1), others are introduction + or rendezvous points (see rend-spec-{v2,v3}.txt).
- 2. Choose a chain of (N-1) onion routers - (R_1...R_N-1) to constitute the path, such that no router - appears in the path twice. + 2. Choose a chain of (N-1) onion routers (R_1...R_N-1) to constitute + the path, such that no router appears in the path twice.
3. If not already connected to the first router in the chain, open a new connection to that router. @@ -1463,11 +1465,16 @@ see tor-design.pdf.
6.1. Relay cells
- Within a circuit, the OP and the exit node use the contents of + Within a circuit, the OP and the end node use the contents of RELAY packets to tunnel end-to-end commands and TCP connections ("Streams") across circuits. End-to-end commands can be initiated by either edge; streams are initiated by the OP.
+ End nodes that accept streams may be: + * exit relays (RELAY_BEGIN, anonymous), + * directory servers (RELAY_BEGIN_DIR, anonymous or non-anonymous), + * onion services (RELAY_BEGIN, anonymous via a rendezvous point). + The payload of each unencrypted RELAY cell consists of: Relay command [1 byte] 'Recognized' [2 bytes] @@ -1493,7 +1500,7 @@ see tor-design.pdf. 14 -- RELAY_EXTEND2 [forward] [control] 15 -- RELAY_EXTENDED2 [backward] [control]
- 32..40 -- Used for hidden services; see rend-spec.txt. + 32..40 -- Used for hidden services; see rend-spec-{v2,v3}.txt.
Commands labelled as "forward" must only be sent by the originator of the circuit. Commands labelled as "backward" must only be sent by @@ -1626,6 +1633,12 @@ see tor-design.pdf. connection to its directory port. RELAY_BEGIN_DIR cells ignore exit policy, since the stream is local to the Tor process.
+ Directory servers may be: + * authoritative directories (RELAY_BEGIN_DIR, usually non-anonymous), + * bridge authoritative directories (RELAY_BEGIN_DIR, anonymous), + * directory mirrors (RELAY_BEGIN_DIR, usually non-anonymous), + * onion service directories (RELAY_BEGIN_DIR, anonymous). + If the Tor relay is not running a directory service, it should respond with a REASON_NOTDIRECTORY RELAY_END cell.
@@ -1690,9 +1703,9 @@ see tor-design.pdf. Because TCP connections can be half-open, we follow an equivalent to TCP's FIN/FIN-ACK/ACK protocol to close streams.
- An exit connection can have a TCP stream in one of three states: - 'OPEN', 'DONE_PACKAGING', and 'DONE_DELIVERING'. For the purposes - of modeling transitions, we treat 'CLOSED' as a fourth state, + An exit (or onion service) connection can have a TCP stream in one of + three states: 'OPEN', 'DONE_PACKAGING', and 'DONE_DELIVERING'. For the + purposes of modeling transitions, we treat 'CLOSED' as a fourth state, although connections in this state are not, in fact, tracked by the onion router.