#include "routerparse.h"
#include "routerset.h"
#include "crypto.h"
+#include "connection_edge.h"
#ifndef MIN
#define MIN(a,b) ((a)<(b)?(a):(b))
}
}
+/**
+ * Send a probe down a circuit that wasn't usable.
+ *
+ * Returns -1 if we couldn't probe, 0 otherwise.
+ */
+static int
+pathbias_send_usable_probe(circuit_t *circ)
+{
+ /* Based on connection_ap_handshake_send_begin() */
+ char payload[CELL_PAYLOAD_SIZE];
+ int payload_len;
+ origin_circuit_t *ocirc = TO_ORIGIN_CIRCUIT(circ);
+ crypt_path_t *cpath_layer = NULL;
+ // XXX: Generate a random 0.a.b.c adddress
+ const char *probe_nonce = "0.1.2.3";
+
+ tor_assert(ocirc);
+
+ cpath_layer = ocirc->cpath->prev;
+
+ if (cpath_layer->state != CPATH_STATE_OPEN) {
+ /* This can happen for cannibalized circuits. Their
+ * last hop isn't yet open */
+ log_info(LD_CIRC,
+ "Got pathbias probe request for unopened circuit %d. "
+ "Opened %d, len %d", ocirc->global_identifier,
+ ocirc->has_opened, ocirc->build_state->desired_path_len);
+ return -1;
+ }
+
+ /* We already went down this road. */
+ if (circ->purpose == CIRCUIT_PURPOSE_PATH_BIAS_TESTING &&
+ ocirc->pathbias_probe_id) {
+ log_info(LD_CIRC,
+ "Got pathbias probe request for circuit %d with "
+ "outstanding probe", ocirc->global_identifier);
+ return -1;
+ }
+
+ circuit_change_purpose(circ, CIRCUIT_PURPOSE_PATH_BIAS_TESTING);
+
+ /* Update timestamp for circuit_expire_building to kill us */
+ tor_gettimeofday(&circ->timestamp_began);
+
+ tor_snprintf(payload,RELAY_PAYLOAD_SIZE, "%s:25", probe_nonce);
+ tor_addr_parse(ô->pathbias_probe_nonce, probe_nonce);
+
+ payload_len = (int)strlen(payload)+1;
+
+ // XXX: need this? Can we assume ipv4 will always be supported?
+ // If not, how do we tell?
+ //if (payload_len <= RELAY_PAYLOAD_SIZE - 4 && edge_conn->begincell_flags) {
+ // set_uint32(payload + payload_len, htonl(edge_conn->begincell_flags));
+ // payload_len += 4;
+ //}
+
+ /* Generate+Store stream id, make sure it's non-zero */
+ ocirc->pathbias_probe_id = get_unique_stream_id_by_circ(ocirc);
+
+ if (ocirc->pathbias_probe_id==0) {
+ log_warn(LD_CIRC,
+ "Ran out of stream IDs on circuit %u during "
+ "pathbias probe attempt.", ocirc->global_identifier);
+ return -1;
+ }
+
+ log_info(LD_CIRC,
+ "Sending pathbias testing cell to %s:25 on stream %d for circ %d.",
+ probe_nonce, ocirc->pathbias_probe_id, ocirc->global_identifier);
+
+ /* Send a test relay cell */
+ if (relay_send_command_from_edge(ocirc->pathbias_probe_id, circ,
+ RELAY_COMMAND_BEGIN, payload,
+ payload_len, cpath_layer) < 0) {
+ log_notice(LD_CIRC,
+ "Failed to send pathbias probe cell on circuit %d.",
+ ocirc->global_identifier);
+ return -1;
+ }
+
+ /* Mark it freshly dirty so it doesn't get expired in the meantime */
+ circ->timestamp_dirty = time(NULL);
+
+ return 0;
+}
+
+/**
+ * Check the response to a pathbias probe.
+ *
+ * If the response is valid, return 0. Otherwise return < 0.
+ */
+int
+pathbias_check_probe_response(circuit_t *circ, cell_t *cell)
+{
+ /* Based on connection_edge_process_relay_cell() */
+ relay_header_t rh;
+ int reason;
+ uint32_t ipv4_host;
+ tor_addr_t host;
+ origin_circuit_t *ocirc = TO_ORIGIN_CIRCUIT(circ);
+
+ tor_assert(cell);
+ tor_assert(ocirc);
+ tor_assert(circ->purpose == CIRCUIT_PURPOSE_PATH_BIAS_TESTING);
+
+ relay_header_unpack(&rh, cell->payload);
+
+ reason = rh.length > 0 ?
+ get_uint8(cell->payload+RELAY_HEADER_SIZE) : END_STREAM_REASON_MISC;
+
+ if (rh.command == RELAY_COMMAND_END &&
+ reason == END_STREAM_REASON_EXITPOLICY &&
+ ocirc->pathbias_probe_id == rh.stream_id) {
+
+ /* Check length+extract host: It is in network order after the reason code.
+ * See connection_edge_end(). */
+ if (rh.length != 9) { /* reason+ipv4+dns_ttl */
+ log_fn(LOG_PROTOCOL_WARN, LD_PROTOCOL,
+ "Path bias probe response length field is insane (%d).",
+ rh.length);
+ return - END_CIRC_REASON_TORPROTOCOL;
+ }
+
+ ipv4_host = get_uint32(cell->payload+RELAY_HEADER_SIZE+1);
+ tor_addr_from_ipv4n(&host, ipv4_host);
+
+ /* Check nonce */
+ if (memcmp(&host, ô->pathbias_probe_nonce, sizeof(tor_addr_t)) == 0) {
+ ocirc->path_state = PATH_STATE_USE_SUCCEEDED;
+ circuit_mark_for_close(circ, END_CIRC_REASON_FINISHED);
+ log_info(LD_CIRC,
+ "Got valid path bias probe back for circ %d, stream %d.",
+ ocirc->global_identifier, ocirc->pathbias_probe_id);
+ return 0;
+ }
+ }
+ log_info(LD_CIRC,
+ "Got another cell back back on pathbias probe circuit %d: "
+ "Command: %d, Reason: %d, Stream-id: %d",
+ ocirc->global_identifier, rh.command, reason, rh.stream_id);
+ return -1;
+}
+
/**
* Check if a circuit was used and/or closed successfully.
*
*
* If we *have* successfully used the circuit, or it appears to
* have been closed by us locally, count it as a success.
+ *
+ * Returns 0 if we're done making decisions with the circ,
+ * or -1 if we want to probe it first.
*/
-void
+int
pathbias_check_close(origin_circuit_t *ocirc, int reason)
{
circuit_t *circ = ô->base_;
if (!pathbias_should_count(ocirc)) {
- return;
+ return 0;
}
if (ocirc->path_state == PATH_STATE_BUILD_SUCCEEDED) {
if (circ->timestamp_dirty) {
+ if (pathbias_send_usable_probe(circ) == 0)
+ return -1;
+ else
+ pathbias_count_unusable(ocirc);
+
/* Any circuit where there were attempted streams but no successful
* streams could be bias */
log_info(LD_CIRC,
reason, circ->purpose, ocirc->has_opened,
circuit_state_to_string(circ->state),
ocirc->build_state->desired_path_len);
- pathbias_count_unusable(ocirc);
+
} else {
if (reason & END_CIRC_REASON_FLAG_REMOTE) {
/* Unused remote circ close reasons all could be bias */
} else if (ocirc->path_state == PATH_STATE_USE_SUCCEEDED) {
pathbias_count_successful_close(ocirc);
}
+
+ return 0;
}
/**
cutoff = s_intro_cutoff;
else if (victim->purpose == CIRCUIT_PURPOSE_C_ESTABLISH_REND)
cutoff = stream_cutoff;
+ else if (victim->purpose == CIRCUIT_PURPOSE_PATH_BIAS_TESTING)
+ cutoff = close_cutoff;
else if (TO_ORIGIN_CIRCUIT(victim)->has_opened &&
victim->state != CIRCUIT_STATE_OPEN)
cutoff = cannibalized_cutoff;
victim->timestamp_dirty > cutoff.tv_sec)
continue;
break;
+ case CIRCUIT_PURPOSE_PATH_BIAS_TESTING:
+ /* Open path bias testing circuits are given a long
+ * time to complete the test, but not forever */
+ TO_ORIGIN_CIRCUIT(victim)->path_state = PATH_STATE_USE_FAILED;
+ break;
case CIRCUIT_PURPOSE_C_INTRODUCING:
/* We keep old introducing circuits around for
* a while in parallel, and they can end up "opened".
circuit_build_times_set_timeout(&circ_times);
}
}
+
+ if (TO_ORIGIN_CIRCUIT(victim)->has_opened &&
+ victim->purpose != CIRCUIT_PURPOSE_PATH_BIAS_TESTING) {
+ /* For path bias: we want to let these guys live for a while
+ * so we get a chance to test them. */
+ log_info(LD_CIRC,
+ "Allowing cannibalized circuit %d time to finish building as a "
+ "pathbias testing circ.",
+ TO_ORIGIN_CIRCUIT(victim)->global_identifier);
+ circuit_change_purpose(victim, CIRCUIT_PURPOSE_PATH_BIAS_TESTING);
+ continue; /* It now should have a longer timeout next time */
+ }
}
/* If this is a hidden service client circuit which is far enough
{
control_event_circuit_status(circ, CIRC_EVENT_BUILT, 0);
- /* Cannibalized circuits count as used for path bias.
- * (PURPOSE_GENERAL circs especially, since they are
- * marked dirty and often go unused after preemptive
- * building). */
- // XXX: Cannibalized now use RELAY_EARLY, which is visible
- // to taggers end-to-end! We really need to probe these instead.
- // Don't forget to remove this check once that's done!
- if (circ->has_opened &&
- circ->build_state->desired_path_len > DEFAULT_ROUTE_LEN) {
- circ->path_state = PATH_STATE_USE_SUCCEEDED;
- }
-
/* Remember that this circuit has finished building. Now if we start
* it building again later (e.g. by extending it), we will know not
* to consider its build time. */
projects / thirdparty / tor.git / commitdiff
