Be even more aggressive about separating local traffic from relayed (ca7c53d3) · Commits · The Tor Project / Core / debian / tor

ChangeLog

+2 −0

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		@@ -7,6 +7,8 @@ Changes in version 0.2.0.3-alpha - 2007-07-29
		- New ConstrainedSockets option to set SO_SNDBUF and SO_RCVBUF on TCP
		sockets. Hopefully useful for Tor servers running on "vserver"
		accounts. (Patch from coderman.)
		- Be even more aggressive about separating local traffic from relayed
		traffic when RelayBandwidthRate is set. (Refines proposal 111.)

		o Security fixes:
		- Directory authorities now call routers Fast if their bandwidth is

doc/spec/proposals/111-local-traffic-priority.txt

+27 −12

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		@@ -118,20 +118,35 @@ Some options:
		(Gosh. How could UDP designs possibly be compatible with rate limiting
		with multiple bucket sizes?)

		Option 4: ?
		Option 4: put both classes of circuits over a single connection, and
		keep track of the last time we read or wrote a high-priority cell. If
		it's been less than N seconds, give the whole connection high priority,
		else give the whole connection low priority.

		Option 5: put both classes of circuits over a single connection, and
		play a complex juggling game by periodically telling the remote side
		what rate limits to set for that connection, so you end up giving
		priority to the right connections but still stick to roughly your
		intended bandwidthrate and relaybandwidthrate.

		Option 6: ?

		Prognosis:

		Of the above options, only option 2 can actually be built and achieve
		what we want. So that's it by default, unless we can come up with
		something better.
		Nick really didn't like option 2 because of the partitioning questions.

		I've put option 4 into place as of Tor 0.2.0.3-alpha.

		In terms of implementation, it will be easy: just add a bit to
		or_connection_t that specifies priority_traffic (used by the initiator
		of the connection to ignore that connection when relaying a create
		request), and another bit that specifies client_only (used by a
		receiving Tor server so it can ignore that connection when sending
		create requests).
		In terms of implementation, it will be easy: just add a time_t to
		or_connection_t that specifies client_used (used by the initiator
		of the connection to rate limit it differently depending on how
		recently the time_t was reset). We currently update client_used
		in three places:
		- command_process_relay_cell() when we receive a relay cell for
		an origin circuit.
		- relay_send_command_from_edge() when we send a relay cell for
		an origin circuit.
		- circuit_deliver_create_cell() when send a create cell.
		We could probably remove the third case and it would still work,
		but hey.

		[Not writing the rest of the proposal until we sort out which option
		we'll take.]

src/or/circuitbuild.c

+1 −1

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		@@ -502,7 +502,7 @@ circuit_deliver_create_cell(circuit_t *circ, uint8_t cell_type,
		append_cell_to_circuit_queue(circ, circ->n_conn, &cell, CELL_DIRECTION_OUT);

		/* mark it so it gets better rate limiting treatment. */
		circ->n_conn->client_used = 1;
		circ->n_conn->client_used = time(NULL);

		return 0;
		}

src/or/circuitlist.c

+1 −22

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		@@ -904,22 +904,6 @@ circuit_expire_all_dirty_circs(void)
		}
		}

		/** Return 1 if there are any origin circuits that use
		* <b>conn</b> as there first hop. Else return 0. */
		static int
		circuit_any_origin_circs_on_conn(or_connection_t *conn)
		{
		circuit_t *circ;

		for (circ=global_circuitlist; circ; circ = circ->next) {
		if (CIRCUIT_IS_ORIGIN(circ) &&
		!circ->marked_for_close &&
		circ->n_conn == conn)
		return 1;
		}
		return 0;
		}

		/** Mark <b>circ</b> to be closed next time we call
		* circuit_close_all_marked(). Do any cleanup needed:
		* - If state is onionskin_pending, remove circ from the onion_pending
		@@ -1044,12 +1028,7 @@ _circuit_mark_for_close(circuit_t *circ, int reason, int line,
		circ->marked_for_close = line;
		circ->marked_for_close_file = file;

		if (CIRCUIT_IS_ORIGIN(circ)) {
		if (circ->n_conn && circ->n_conn->client_used) {
		circ->n_conn->client_used =
		circuit_any_origin_circs_on_conn(circ->n_conn);
		}
		} else {
		if (!CIRCUIT_IS_ORIGIN(circ)) {
		or_circuit_t *or_circ = TO_OR_CIRCUIT(circ);
		if (or_circ->rend_splice) {
		if (!or_circ->rend_splice->_base.marked_for_close) {

src/or/command.c

+6 −0

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		@@ -322,6 +322,12 @@ command_process_relay_cell(cell_t cell, or_connection_t conn)
		return;
		}

		if (CIRCUIT_IS_ORIGIN(circ)) {
		/* if we're a server and treating connections with recent local
		* traffic better, then this is one of them. */
		conn->client_used = time(NULL);
		}

		if (!CIRCUIT_IS_ORIGIN(circ) &&
		cell->circ_id == TO_OR_CIRCUIT(circ)->p_circ_id)
		direction = CELL_DIRECTION_OUT;