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author | Mike Perry <mikeperry-git@torproject.org> | 2020-06-10 17:39:13 -0500 |
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committer | Mike Perry <mikeperry-git@torproject.org> | 2020-06-10 17:39:13 -0500 |
commit | f26e739db4d6d330165efe72cee8812d99a49598 (patch) | |
tree | d302af6d79040256b6882c24b1cc4ebfc897d544 /padding-spec.txt | |
parent | 87eefe8c537bdbab2a34394ee094338e862e9d69 (diff) | |
download | torspec-f26e739db4d6d330165efe72cee8812d99a49598.tar.gz torspec-f26e739db4d6d330165efe72cee8812d99a49598.zip |
Padding spec update for Bug 30992's machine_ctr field.
Diffstat (limited to 'padding-spec.txt')
-rw-r--r-- | padding-spec.txt | 13 |
1 files changed, 12 insertions, 1 deletions
diff --git a/padding-spec.txt b/padding-spec.txt index 22ed171..b9d99b7 100644 --- a/padding-spec.txt +++ b/padding-spec.txt @@ -325,13 +325,19 @@ the anonymity and load-balancing implications of their choices. u8 command IN [CIRCPAD_COMMAND_START, CIRCPAD_COMMAND_STOP]; u8 machine_type IN [CIRCPAD_MACHINE_CIRC_SETUP]; + + u8 unused; // Formerly echo_request + + u32 machine_ctr; }; When a client wants to start a circuit padding machine, it first checks that the desired destination hop advertises the appropriate subprotocol version for that machine. It then sends a circpad_negotiate cell to that hop with command=CIRCPAD_COMMAND_START, and machine_type=CIRCPAD_MACHINE_CIRC_SETUP (for - the circ setup machine, the destination hop is the second hop in the circuit). + the circ setup machine, the destination hop is the second hop in the + circuit). The machine_ctr is the count of which machine instance this is on + the circuit. It is used to disambiguate shutdown requests. When a relay receives a circpad_negotiate cell, it checks that it supports the requested machine, and sends a circpad_negotiated cell, which is formatted @@ -343,6 +349,8 @@ the anonymity and load-balancing implications of their choices. u8 response IN [CIRCPAD_RESPONSE_OK, CIRCPAD_RESPONSE_ERR]; u8 machine_type IN [CIRCPAD_MACHINE_CIRC_SETUP]; + + u32 machine_ctr; }; If the machine is supported, the response field will contain @@ -352,6 +360,9 @@ the anonymity and load-balancing implications of their choices. (clients MUST only send circpad_negotiate, and relays MUST only send circpad_negotiated for this purpose). + If the machine_ctr does not match the current machine instance count + on the circuit, the command is ignored. + 3.2. Circuit Padding Machine Message Management Clients MAY send padding cells towards the relay before receiving the |