1 /* Copyright (c) 2001 Matej Pfajfar.
2 * Copyright (c) 2001-2004, Roger Dingledine.
3 * Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson.
4 * Copyright (c) 2007-2019, The Tor Project, Inc. */
5 /* See LICENSE for licensing information */
9 * \brief Functions for processing incoming cells.
11 * When we receive a cell from a client or a relay, it arrives on some
12 * channel, and tells us what to do with it. In this module, we dispatch based
13 * on the cell type using the functions command_process_cell() and
14 * command_process_var_cell(), and deal with the cell accordingly. (These
15 * handlers are installed on a channel with the command_setup_channel()
18 * Channels have a chance to handle some cell types on their own before they
19 * are ever passed here --- typically, they do this for cells that are
20 * specific to a given channel type. For example, in channeltls.c, the cells
21 * for the initial connection handshake are handled before we get here. (Of
22 * course, the fact that there _is_ only one channel type for now means that
23 * we may have gotten the factoring wrong here.)
25 * Handling other cell types is mainly farmed off to other modules, after
26 * initial sanity-checking. CREATE* cells are handled ultimately in onion.c,
27 * CREATED* cells trigger circuit creation in circuitbuild.c, DESTROY cells
28 * are handled here (since they're simple), and RELAY cells, in all their
29 * complexity, are passed off to relay.c.
32 /* In-points to command.c:
34 * - command_process_cell(), called from
35 * incoming cell handlers of channel_t instances;
36 * callbacks registered in command_setup_channel(),
37 * called when channels are created in circuitbuild.c
39 #include "core/or/or.h"
40 #include "app/config/config.h"
41 #include "core/crypto/onion_crypto.h"
42 #include "core/mainloop/connection.h"
43 #include "core/mainloop/cpuworker.h"
44 #include "core/or/channel.h"
45 #include "core/or/circuitbuild.h"
46 #include "core/or/circuitlist.h"
47 #include "core/or/command.h"
48 #include "core/or/connection_or.h"
49 #include "core/or/dos.h"
50 #include "core/or/onion.h"
51 #include "core/or/relay.h"
52 #include "feature/control/control_events.h"
53 #include "feature/hibernate/hibernate.h"
54 #include "feature/nodelist/describe.h"
55 #include "feature/nodelist/nodelist.h"
56 #include "feature/nodelist/routerlist.h"
57 #include "feature/relay/routermode.h"
58 #include "feature/stats/rephist.h"
59 #include "lib/crypt_ops/crypto_util.h"
61 #include "core/or/cell_st.h"
62 #include "core/or/or_circuit_st.h"
63 #include "core/or/origin_circuit_st.h"
64 #include "core/or/var_cell_st.h"
66 /** How many CELL_CREATE cells have we received, ever? */
67 uint64_t stats_n_create_cells_processed
= 0;
68 /** How many CELL_CREATED cells have we received, ever? */
69 uint64_t stats_n_created_cells_processed
= 0;
70 /** How many CELL_RELAY cells have we received, ever? */
71 uint64_t stats_n_relay_cells_processed
= 0;
72 /** How many CELL_DESTROY cells have we received, ever? */
73 uint64_t stats_n_destroy_cells_processed
= 0;
75 /* Handle an incoming channel */
76 static void command_handle_incoming_channel(channel_listener_t
*listener
,
79 /* These are the main functions for processing cells */
80 static void command_process_create_cell(cell_t
*cell
, channel_t
*chan
);
81 static void command_process_created_cell(cell_t
*cell
, channel_t
*chan
);
82 static void command_process_relay_cell(cell_t
*cell
, channel_t
*chan
);
83 static void command_process_destroy_cell(cell_t
*cell
, channel_t
*chan
);
85 /** Convert the cell <b>command</b> into a lower-case, human-readable
88 cell_command_to_string(uint8_t command
)
91 case CELL_PADDING
: return "padding";
92 case CELL_CREATE
: return "create";
93 case CELL_CREATED
: return "created";
94 case CELL_RELAY
: return "relay";
95 case CELL_DESTROY
: return "destroy";
96 case CELL_CREATE_FAST
: return "create_fast";
97 case CELL_CREATED_FAST
: return "created_fast";
98 case CELL_VERSIONS
: return "versions";
99 case CELL_NETINFO
: return "netinfo";
100 case CELL_RELAY_EARLY
: return "relay_early";
101 case CELL_CREATE2
: return "create2";
102 case CELL_CREATED2
: return "created2";
103 case CELL_VPADDING
: return "vpadding";
104 case CELL_CERTS
: return "certs";
105 case CELL_AUTH_CHALLENGE
: return "auth_challenge";
106 case CELL_AUTHENTICATE
: return "authenticate";
107 case CELL_AUTHORIZE
: return "authorize";
108 default: return "unrecognized";
112 #ifdef KEEP_TIMING_STATS
113 /** This is a wrapper function around the actual function that processes the
114 * <b>cell</b> that just arrived on <b>conn</b>. Increment <b>*time</b>
115 * by the number of microseconds used by the call to <b>*func(cell, conn)</b>.
118 command_time_process_cell(cell_t
*cell
, channel_t
*chan
, int *time
,
119 void (*func
)(cell_t
*, channel_t
*))
121 struct timeval start
, end
;
124 tor_gettimeofday(&start
);
128 tor_gettimeofday(&end
);
129 time_passed
= tv_udiff(&start
, &end
) ;
131 if (time_passed
> 10000) { /* more than 10ms */
132 log_debug(LD_OR
,"That call just took %ld ms.",time_passed
/1000);
134 if (time_passed
< 0) {
135 log_info(LD_GENERAL
,"That call took us back in time!");
138 *time
+= time_passed
;
140 #endif /* defined(KEEP_TIMING_STATS) */
142 /** Process a <b>cell</b> that was just received on <b>chan</b>. Keep internal
143 * statistics about how many of each cell we've processed so far
144 * this second, and the total number of microseconds it took to
145 * process each type of cell.
148 command_process_cell(channel_t
*chan
, cell_t
*cell
)
150 #ifdef KEEP_TIMING_STATS
151 /* how many of each cell have we seen so far this second? needs better
153 static int num_create
=0, num_created
=0, num_relay
=0, num_destroy
=0;
154 /* how long has it taken to process each type of cell? */
155 static int create_time
=0, created_time
=0, relay_time
=0, destroy_time
=0;
156 static time_t current_second
= 0; /* from previous calls to time */
158 time_t now
= time(NULL
);
160 if (now
> current_second
) { /* the second has rolled over */
163 "At end of second: %d creates (%d ms), %d createds (%d ms), "
164 "%d relays (%d ms), %d destroys (%d ms)",
165 num_create
, create_time
/1000,
166 num_created
, created_time
/1000,
167 num_relay
, relay_time
/1000,
168 num_destroy
, destroy_time
/1000);
171 num_create
= num_created
= num_relay
= num_destroy
= 0;
172 create_time
= created_time
= relay_time
= destroy_time
= 0;
174 /* remember which second it is, for next time */
175 current_second
= now
;
177 #endif /* defined(KEEP_TIMING_STATS) */
179 #ifdef KEEP_TIMING_STATS
180 #define PROCESS_CELL(tp, cl, cn) STMT_BEGIN { \
182 command_time_process_cell(cl, cn, & tp ## time , \
183 command_process_ ## tp ## _cell); \
185 #else /* !(defined(KEEP_TIMING_STATS)) */
186 #define PROCESS_CELL(tp, cl, cn) command_process_ ## tp ## _cell(cl, cn)
187 #endif /* defined(KEEP_TIMING_STATS) */
189 switch (cell
->command
) {
191 case CELL_CREATE_FAST
:
193 ++stats_n_create_cells_processed
;
194 PROCESS_CELL(create
, cell
, chan
);
197 case CELL_CREATED_FAST
:
199 ++stats_n_created_cells_processed
;
200 PROCESS_CELL(created
, cell
, chan
);
203 case CELL_RELAY_EARLY
:
204 ++stats_n_relay_cells_processed
;
205 PROCESS_CELL(relay
, cell
, chan
);
208 ++stats_n_destroy_cells_processed
;
209 PROCESS_CELL(destroy
, cell
, chan
);
212 log_fn(LOG_INFO
, LD_PROTOCOL
,
213 "Cell of unknown or unexpected type (%d) received. "
220 /** Process an incoming var_cell from a channel; in the current protocol all
221 * the var_cells are handshake-related and handled below the channel layer,
222 * so this just logs a warning and drops the cell.
226 command_process_var_cell(channel_t
*chan
, var_cell_t
*var_cell
)
229 tor_assert(var_cell
);
231 log_info(LD_PROTOCOL
,
232 "Received unexpected var_cell above the channel layer of type %d"
237 /** Process a 'create' <b>cell</b> that just arrived from <b>chan</b>. Make a
238 * new circuit with the p_circ_id specified in cell. Put the circuit in state
239 * onionskin_pending, and pass the onionskin to the cpuworker. Circ will get
240 * picked up again when the cpuworker finishes decrypting it.
243 command_process_create_cell(cell_t
*cell
, channel_t
*chan
)
246 const or_options_t
*options
= get_options();
248 create_cell_t
*create_cell
;
254 "Got a CREATE cell for circ_id %u on channel %"PRIu64
256 (unsigned)cell
->circ_id
,
257 (chan
->global_identifier
), chan
);
259 /* First thing we do, even though the cell might be invalid, is inform the
260 * DoS mitigation subsystem layer of this event. Validation is done by this
262 dos_cc_new_create_cell(chan
);
264 /* We check for the conditions that would make us drop the cell before
265 * we check for the conditions that would make us send a DESTROY back,
266 * since those conditions would make a DESTROY nonsensical. */
267 if (cell
->circ_id
== 0) {
268 log_fn(LOG_PROTOCOL_WARN
, LD_PROTOCOL
,
269 "Received a create cell (type %d) from %s with zero circID; "
270 " ignoring.", (int)cell
->command
,
271 channel_get_actual_remote_descr(chan
));
275 if (circuit_id_in_use_on_channel(cell
->circ_id
, chan
)) {
276 const node_t
*node
= node_get_by_id(chan
->identity_digest
);
277 log_fn(LOG_PROTOCOL_WARN
, LD_PROTOCOL
,
278 "Received CREATE cell (circID %u) for known circ. "
279 "Dropping (age %d).",
280 (unsigned)cell
->circ_id
,
281 (int)(time(NULL
) - channel_when_created(chan
)));
283 char *p
= esc_for_log(node_get_platform(node
));
284 log_fn(LOG_PROTOCOL_WARN
, LD_PROTOCOL
,
285 "Details: router %s, platform %s.",
286 node_describe(node
), p
);
292 if (we_are_hibernating()) {
294 "Received create cell but we're shutting down. Sending back "
296 channel_send_destroy(cell
->circ_id
, chan
,
297 END_CIRC_REASON_HIBERNATING
);
301 /* Check if we should apply a defense for this channel. */
302 if (dos_cc_get_defense_type(chan
) == DOS_CC_DEFENSE_REFUSE_CELL
) {
303 channel_send_destroy(cell
->circ_id
, chan
,
304 END_CIRC_REASON_RESOURCELIMIT
);
308 if (!server_mode(options
) ||
309 (!public_server_mode(options
) && channel_is_outgoing(chan
))) {
310 log_fn(LOG_PROTOCOL_WARN
, LD_PROTOCOL
,
311 "Received create cell (type %d) from %s, but we're connected "
312 "to it as a client. "
313 "Sending back a destroy.",
314 (int)cell
->command
, channel_get_canonical_remote_descr(chan
));
315 channel_send_destroy(cell
->circ_id
, chan
,
316 END_CIRC_REASON_TORPROTOCOL
);
320 /* If the high bit of the circuit ID is not as expected, close the
322 if (chan
->wide_circ_ids
)
323 id_is_high
= cell
->circ_id
& (1u<<31);
325 id_is_high
= cell
->circ_id
& (1u<<15);
327 chan
->circ_id_type
== CIRC_ID_TYPE_HIGHER
) ||
329 chan
->circ_id_type
== CIRC_ID_TYPE_LOWER
)) {
330 log_fn(LOG_PROTOCOL_WARN
, LD_PROTOCOL
,
331 "Received create cell with unexpected circ_id %u. Closing.",
332 (unsigned)cell
->circ_id
);
333 channel_send_destroy(cell
->circ_id
, chan
,
334 END_CIRC_REASON_TORPROTOCOL
);
338 circ
= or_circuit_new(cell
->circ_id
, chan
);
339 circ
->base_
.purpose
= CIRCUIT_PURPOSE_OR
;
340 circuit_set_state(TO_CIRCUIT(circ
), CIRCUIT_STATE_ONIONSKIN_PENDING
);
341 create_cell
= tor_malloc_zero(sizeof(create_cell_t
));
342 if (create_cell_parse(create_cell
, cell
) < 0) {
343 tor_free(create_cell
);
344 log_fn(LOG_PROTOCOL_WARN
, LD_OR
,
345 "Bogus/unrecognized create cell; closing.");
346 circuit_mark_for_close(TO_CIRCUIT(circ
), END_CIRC_REASON_TORPROTOCOL
);
350 if (!channel_is_client(chan
)) {
351 /* remember create types we've seen, but don't remember them from
352 * clients, to be extra conservative about client statistics. */
353 rep_hist_note_circuit_handshake_requested(create_cell
->handshake_type
);
356 if (create_cell
->handshake_type
!= ONION_HANDSHAKE_TYPE_FAST
) {
357 /* hand it off to the cpuworkers, and then return. */
359 if (assign_onionskin_to_cpuworker(circ
, create_cell
) < 0) {
360 log_debug(LD_GENERAL
,"Failed to hand off onionskin. Closing.");
361 circuit_mark_for_close(TO_CIRCUIT(circ
), END_CIRC_REASON_RESOURCELIMIT
);
364 log_debug(LD_OR
,"success: handed off onionskin.");
366 /* This is a CREATE_FAST cell; we can handle it immediately without using
368 uint8_t keys
[CPATH_KEY_MATERIAL_LEN
];
369 uint8_t rend_circ_nonce
[DIGEST_LEN
];
371 created_cell_t created_cell
;
373 memset(&created_cell
, 0, sizeof(created_cell
));
374 len
= onion_skin_server_handshake(ONION_HANDSHAKE_TYPE_FAST
,
375 create_cell
->onionskin
,
376 create_cell
->handshake_len
,
379 keys
, CPATH_KEY_MATERIAL_LEN
,
381 tor_free(create_cell
);
383 log_warn(LD_OR
,"Failed to generate key material. Closing.");
384 circuit_mark_for_close(TO_CIRCUIT(circ
), END_CIRC_REASON_INTERNAL
);
387 created_cell
.cell_type
= CELL_CREATED_FAST
;
388 created_cell
.handshake_len
= len
;
390 if (onionskin_answer(circ
, &created_cell
,
391 (const char *)keys
, sizeof(keys
),
392 rend_circ_nonce
)<0) {
393 log_warn(LD_OR
,"Failed to reply to CREATE_FAST cell. Closing.");
394 circuit_mark_for_close(TO_CIRCUIT(circ
), END_CIRC_REASON_INTERNAL
);
397 memwipe(keys
, 0, sizeof(keys
));
401 /** Process a 'created' <b>cell</b> that just arrived from <b>chan</b>.
403 * that it's intended for. If we're not the origin of the circuit, package
404 * the 'created' cell in an 'extended' relay cell and pass it back. If we
405 * are the origin of the circuit, send it to circuit_finish_handshake() to
406 * finish processing keys, and then call circuit_send_next_onion_skin() to
407 * extend to the next hop in the circuit if necessary.
410 command_process_created_cell(cell_t
*cell
, channel_t
*chan
)
413 extended_cell_t extended_cell
;
415 circ
= circuit_get_by_circid_channel(cell
->circ_id
, chan
);
419 "(circID %u) unknown circ (probably got a destroy earlier). "
420 "Dropping.", (unsigned)cell
->circ_id
);
424 if (circ
->n_circ_id
!= cell
->circ_id
|| circ
->n_chan
!= chan
) {
425 log_fn(LOG_PROTOCOL_WARN
,LD_PROTOCOL
,
426 "got created cell from Tor client? Closing.");
427 circuit_mark_for_close(circ
, END_CIRC_REASON_TORPROTOCOL
);
431 if (created_cell_parse(&extended_cell
.created_cell
, cell
) < 0) {
432 log_fn(LOG_PROTOCOL_WARN
, LD_OR
, "Unparseable created cell.");
433 circuit_mark_for_close(circ
, END_CIRC_REASON_TORPROTOCOL
);
437 if (CIRCUIT_IS_ORIGIN(circ
)) { /* we're the OP. Handshake this. */
438 origin_circuit_t
*origin_circ
= TO_ORIGIN_CIRCUIT(circ
);
440 log_debug(LD_OR
,"at OP. Finishing handshake.");
441 if ((err_reason
= circuit_finish_handshake(origin_circ
,
442 &extended_cell
.created_cell
)) < 0) {
443 circuit_mark_for_close(circ
, -err_reason
);
446 log_debug(LD_OR
,"Moving to next skin.");
447 if ((err_reason
= circuit_send_next_onion_skin(origin_circ
)) < 0) {
448 log_info(LD_OR
,"circuit_send_next_onion_skin failed.");
449 /* XXX push this circuit_close lower */
450 circuit_mark_for_close(circ
, -err_reason
);
453 } else { /* pack it into an extended relay cell, and send it. */
456 uint8_t payload
[RELAY_PAYLOAD_SIZE
];
458 "Converting created cell to extended relay cell, sending.");
459 memset(payload
, 0, sizeof(payload
));
460 if (extended_cell
.created_cell
.cell_type
== CELL_CREATED2
)
461 extended_cell
.cell_type
= RELAY_COMMAND_EXTENDED2
;
463 extended_cell
.cell_type
= RELAY_COMMAND_EXTENDED
;
464 if (extended_cell_format(&command
, &len
, payload
, &extended_cell
) < 0) {
465 log_fn(LOG_PROTOCOL_WARN
, LD_OR
, "Can't format extended cell.");
466 circuit_mark_for_close(circ
, END_CIRC_REASON_TORPROTOCOL
);
470 relay_send_command_from_edge(0, circ
, command
,
471 (const char*)payload
, len
, NULL
);
475 /** Process a 'relay' or 'relay_early' <b>cell</b> that just arrived from
476 * <b>conn</b>. Make sure it came in with a recognized circ_id. Pass it on to
477 * circuit_receive_relay_cell() for actual processing.
480 command_process_relay_cell(cell_t
*cell
, channel_t
*chan
)
482 const or_options_t
*options
= get_options();
484 int reason
, direction
;
485 uint32_t orig_delivered_bw
= 0;
486 uint32_t orig_overhead_bw
= 0;
488 circ
= circuit_get_by_circid_channel(cell
->circ_id
, chan
);
492 "unknown circuit %u on connection from %s. Dropping.",
493 (unsigned)cell
->circ_id
,
494 channel_get_canonical_remote_descr(chan
));
498 if (circ
->state
== CIRCUIT_STATE_ONIONSKIN_PENDING
) {
499 log_fn(LOG_PROTOCOL_WARN
,LD_PROTOCOL
,"circuit in create_wait. Closing.");
500 circuit_mark_for_close(circ
, END_CIRC_REASON_TORPROTOCOL
);
504 if (CIRCUIT_IS_ORIGIN(circ
)) {
505 /* if we're a relay and treating connections with recent local
506 * traffic better, then this is one of them. */
507 channel_timestamp_client(chan
);
509 /* Count all circuit bytes here for control port accuracy. We want
510 * to count even invalid/dropped relay cells, hence counting
511 * before the recognized check and the connection_edge_process_relay
514 origin_circuit_t
*ocirc
= TO_ORIGIN_CIRCUIT(circ
);
516 /* Count the payload bytes only. We don't care about cell headers */
517 ocirc
->n_read_circ_bw
= tor_add_u32_nowrap(ocirc
->n_read_circ_bw
,
520 /* Stash the original delivered and overhead values. These values are
521 * updated by circuit_read_valid_data() during cell processing by
522 * connection_edge_process_relay_cell(), called from
523 * circuit_receive_relay_cell() below. If they do not change, we inform
524 * the control port about dropped cells immediately after the call
525 * to circuit_receive_relay_cell() below. */
526 orig_delivered_bw
= ocirc
->n_delivered_read_circ_bw
;
527 orig_overhead_bw
= ocirc
->n_overhead_read_circ_bw
;
530 if (!CIRCUIT_IS_ORIGIN(circ
) &&
531 chan
== TO_OR_CIRCUIT(circ
)->p_chan
&&
532 cell
->circ_id
== TO_OR_CIRCUIT(circ
)->p_circ_id
)
533 direction
= CELL_DIRECTION_OUT
;
535 direction
= CELL_DIRECTION_IN
;
537 /* If we have a relay_early cell, make sure that it's outbound, and we've
538 * gotten no more than MAX_RELAY_EARLY_CELLS_PER_CIRCUIT of them. */
539 if (cell
->command
== CELL_RELAY_EARLY
) {
540 if (direction
== CELL_DIRECTION_IN
) {
541 /* Inbound early cells could once be encountered as a result of
542 * bug 1038; but relays running versions before 0.2.1.19 are long
543 * gone from the network, so any such cells now are surprising. */
545 "Received an inbound RELAY_EARLY cell on circuit %u."
546 " Closing circuit. Please report this event,"
547 " along with the following message.",
548 (unsigned)cell
->circ_id
);
549 if (CIRCUIT_IS_ORIGIN(circ
)) {
550 circuit_log_path(LOG_WARN
, LD_OR
, TO_ORIGIN_CIRCUIT(circ
));
551 /* Always emit a bandwidth event for closed circs */
552 control_event_circ_bandwidth_used_for_circ(TO_ORIGIN_CIRCUIT(circ
));
553 } else if (circ
->n_chan
) {
554 log_warn(LD_OR
, " upstream=%s",
555 channel_get_actual_remote_descr(circ
->n_chan
));
557 circuit_mark_for_close(circ
, END_CIRC_REASON_TORPROTOCOL
);
560 or_circuit_t
*or_circ
= TO_OR_CIRCUIT(circ
);
561 if (or_circ
->remaining_relay_early_cells
== 0) {
562 log_fn(LOG_PROTOCOL_WARN
, LD_OR
,
563 "Received too many RELAY_EARLY cells on circ %u from %s."
565 (unsigned)cell
->circ_id
,
566 safe_str(channel_get_canonical_remote_descr(chan
)));
567 circuit_mark_for_close(circ
, END_CIRC_REASON_TORPROTOCOL
);
570 --or_circ
->remaining_relay_early_cells
;
574 if ((reason
= circuit_receive_relay_cell(cell
, circ
, direction
)) < 0) {
575 log_fn(LOG_PROTOCOL_WARN
,LD_PROTOCOL
,"circuit_receive_relay_cell "
576 "(%s) failed. Closing.",
577 direction
==CELL_DIRECTION_OUT
?"forward":"backward");
578 /* Always emit a bandwidth event for closed circs */
579 if (CIRCUIT_IS_ORIGIN(circ
)) {
580 control_event_circ_bandwidth_used_for_circ(TO_ORIGIN_CIRCUIT(circ
));
582 circuit_mark_for_close(circ
, -reason
);
585 if (CIRCUIT_IS_ORIGIN(circ
)) {
586 origin_circuit_t
*ocirc
= TO_ORIGIN_CIRCUIT(circ
);
588 /* If neither the delivered nor overhead values changed, this cell
589 * was dropped due to being invalid by one of the error codepaths in
590 * connection_edge_process_relay_cell(), called by
591 * circuit_receive_relay_cell().
593 * Valid cells, on the other hand, call circuit_read_valid_data()
594 * to update these values upon processing them.
596 * So, if the values are the same as those stored above,
597 * emit a control port event for CIRC_BW, so the controller can
598 * react quickly to invalid cells. */
599 if (orig_delivered_bw
== ocirc
->n_delivered_read_circ_bw
&&
600 orig_overhead_bw
== ocirc
->n_overhead_read_circ_bw
) {
601 control_event_circ_bandwidth_used_for_circ(ocirc
);
605 /* If this is a cell in an RP circuit, count it as part of the
606 hidden service stats */
607 if (options
->HiddenServiceStatistics
&&
608 !CIRCUIT_IS_ORIGIN(circ
) &&
609 TO_OR_CIRCUIT(circ
)->circuit_carries_hs_traffic_stats
) {
610 rep_hist_seen_new_rp_cell();
614 /** Process a 'destroy' <b>cell</b> that just arrived from
615 * <b>chan</b>. Find the circ that it refers to (if any).
617 * If the circ is in state
618 * onionskin_pending, then call onion_pending_remove() to remove it
619 * from the pending onion list (note that if it's already being
620 * processed by the cpuworker, it won't be in the list anymore; but
621 * when the cpuworker returns it, the circuit will be gone, and the
622 * cpuworker response will be dropped).
624 * Then mark the circuit for close (which marks all edges for close,
625 * and passes the destroy cell onward if necessary).
628 command_process_destroy_cell(cell_t
*cell
, channel_t
*chan
)
633 circ
= circuit_get_by_circid_channel(cell
->circ_id
, chan
);
635 log_info(LD_OR
,"unknown circuit %u on connection from %s. Dropping.",
636 (unsigned)cell
->circ_id
,
637 channel_get_canonical_remote_descr(chan
));
640 log_debug(LD_OR
,"Received for circID %u.",(unsigned)cell
->circ_id
);
642 reason
= (uint8_t)cell
->payload
[0];
643 circ
->received_destroy
= 1;
645 if (!CIRCUIT_IS_ORIGIN(circ
) &&
646 chan
== TO_OR_CIRCUIT(circ
)->p_chan
&&
647 cell
->circ_id
== TO_OR_CIRCUIT(circ
)->p_circ_id
) {
648 /* the destroy came from behind */
649 circuit_set_p_circid_chan(TO_OR_CIRCUIT(circ
), 0, NULL
);
650 circuit_mark_for_close(circ
, reason
|END_CIRC_REASON_FLAG_REMOTE
);
651 } else { /* the destroy came from ahead */
652 circuit_set_n_circid_chan(circ
, 0, NULL
);
653 if (CIRCUIT_IS_ORIGIN(circ
)) {
654 circuit_mark_for_close(circ
, reason
|END_CIRC_REASON_FLAG_REMOTE
);
657 log_debug(LD_OR
, "Delivering 'truncated' back.");
658 payload
[0] = (char)reason
;
659 relay_send_command_from_edge(0, circ
, RELAY_COMMAND_TRUNCATED
,
660 payload
, sizeof(payload
), NULL
);
665 /** Callback to handle a new channel; call command_setup_channel() to give
666 * it the right cell handlers.
670 command_handle_incoming_channel(channel_listener_t
*listener
, channel_t
*chan
)
672 tor_assert(listener
);
675 command_setup_channel(chan
);
678 /** Given a channel, install the right handlers to process incoming
683 command_setup_channel(channel_t
*chan
)
687 channel_set_cell_handlers(chan
,
688 command_process_cell
,
689 command_process_var_cell
);
692 /** Given a listener, install the right handler to process incoming
697 command_setup_listener(channel_listener_t
*listener
)
699 tor_assert(listener
);
700 tor_assert(listener
->state
== CHANNEL_LISTENER_STATE_LISTENING
);
702 channel_listener_set_listener_fn(listener
, command_handle_incoming_channel
);