tor/src/or/command.c

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/* Copyright (c) 2001 Matej Pfajfar.
* Copyright (c) 2001-2004, Roger Dingledine.
* Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson. */
/* See LICENSE for licensing information */
/* $Id$ */
const char command_c_id[] =
"$Id$";
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/**
* \file command.c
* \brief Functions for processing incoming cells.
**/
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/* In-points to command.c:
*
* - command_process_cell(), called from
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* connection_or_process_cells_from_inbuf() in connection_or.c
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*/
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#include "or.h"
/** Keep statistics about how many of each type of cell we've received. */
uint64_t stats_n_padding_cells_processed = 0;
uint64_t stats_n_create_cells_processed = 0;
uint64_t stats_n_created_cells_processed = 0;
uint64_t stats_n_relay_cells_processed = 0;
uint64_t stats_n_destroy_cells_processed = 0;
/* These are the main four functions for processing cells */
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static void command_process_create_cell(cell_t *cell, connection_t *conn);
static void command_process_created_cell(cell_t *cell, connection_t *conn);
static void command_process_relay_cell(cell_t *cell, connection_t *conn);
static void command_process_destroy_cell(cell_t *cell, connection_t *conn);
#ifdef KEEP_TIMING_STATS
/** This is a wrapper function around the actual function that processes the
* <b>cell</b> that just arrived on <b>conn</b>. Increment <b>*time</b>
* by the number of microseconds used by the call to <b>*func(cell, conn)</b>.
*/
static void
command_time_process_cell(cell_t *cell, connection_t *conn, int *time,
void (*func)(cell_t *, connection_t *))
{
struct timeval start, end;
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long time_passed;
tor_gettimeofday(&start);
(*func)(cell, conn);
tor_gettimeofday(&end);
time_passed = tv_udiff(&start, &end) ;
if (time_passed > 10000) { /* more than 10ms */
debug(LD_OR,"That call just took %ld ms.",time_passed/1000);
}
if (time_passed < 0) {
info(LD_GENERAL,"That call took us back in time!");
time_passed = 0;
}
*time += time_passed;
}
#endif
/** Process a <b>cell</b> that was just received on <b>conn</b>. Keep internal
* statistics about how many of each cell we've processed so far
* this second, and the total number of microseconds it took to
* process each type of cell.
*/
void
command_process_cell(cell_t *cell, connection_t *conn)
{
#ifdef KEEP_TIMING_STATS
/* how many of each cell have we seen so far this second? needs better
* name. */
static int num_create=0, num_created=0, num_relay=0, num_destroy=0;
/* how long has it taken to process each type of cell? */
static int create_time=0, created_time=0, relay_time=0, destroy_time=0;
static time_t current_second = 0; /* from previous calls to time */
time_t now = time(NULL);
if (now > current_second) { /* the second has rolled over */
/* print stats */
info(LD_OR,"At end of second: %d creates (%d ms), %d createds (%d ms), "
"%d relays (%d ms), %d destroys (%d ms)",
num_create, create_time/1000,
num_created, created_time/1000,
num_relay, relay_time/1000,
num_destroy, destroy_time/1000);
/* zero out stats */
num_create = num_created = num_relay = num_destroy = 0;
create_time = created_time = relay_time = destroy_time = 0;
/* remember which second it is, for next time */
current_second = now;
}
#endif
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switch (cell->command) {
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case CELL_PADDING:
++stats_n_padding_cells_processed;
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/* do nothing */
break;
case CELL_CREATE:
case CELL_CREATE_FAST:
++stats_n_create_cells_processed;
#ifdef KEEP_TIMING_STATS
++num_create;
command_time_process_cell(cell, conn, &create_time,
command_process_create_cell);
#else
command_process_create_cell(cell, conn);
#endif
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break;
case CELL_CREATED:
case CELL_CREATED_FAST:
++stats_n_created_cells_processed;
#ifdef KEEP_TIMING_STATS
++num_created;
command_time_process_cell(cell, conn, &created_time,
command_process_created_cell);
#else
command_process_created_cell(cell, conn);
#endif
break;
case CELL_RELAY:
++stats_n_relay_cells_processed;
#ifdef KEEP_TIMING_STATS
++num_relay;
command_time_process_cell(cell, conn, &relay_time,
command_process_relay_cell);
#else
command_process_relay_cell(cell, conn);
#endif
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break;
case CELL_DESTROY:
++stats_n_destroy_cells_processed;
#ifdef KEEP_TIMING_STATS
++num_destroy;
command_time_process_cell(cell, conn, &destroy_time,
command_process_destroy_cell);
#else
command_process_destroy_cell(cell, conn);
#endif
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break;
default:
log_fn(LOG_PROTOCOL_WARN, LD_PROTOCOL,
"Cell of unknown type (%d) received. Dropping.", cell->command);
break;
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}
}
/** Process a 'create' <b>cell</b> that just arrived from <b>conn</b>. Make a
* new circuit with the p_circ_id specified in cell. Put the circuit in state
* onionskin_pending, and pass the onionskin to the cpuworker. Circ will get
* picked up again when the cpuworker finishes decrypting it.
*/
static void
command_process_create_cell(cell_t *cell, connection_t *conn)
{
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circuit_t *circ;
int id_is_high;
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if (we_are_hibernating()) {
info(LD_OR,"Received create cell but we're shutting down. Sending back "
"destroy.");
connection_or_send_destroy(cell->circ_id, conn,
END_CIRC_REASON_HIBERNATING);
return;
}
/* If the high bit of the circuit ID is not as expected, then switch
* which half of the space we'll use for our own CREATE cells.
*
* This can happen because Tor 0.0.9pre5 and earlier decide which
* half to use based on nickname, and we now use identity keys.
*/
id_is_high = cell->circ_id & (1<<15);
if (id_is_high && conn->circ_id_type == CIRC_ID_TYPE_HIGHER) {
info(LD_OR, "Got a high circuit ID from %s (%d); switching to "
"low circuit IDs.",
conn->nickname ? conn->nickname : "client", conn->s);
conn->circ_id_type = CIRC_ID_TYPE_LOWER;
} else if (!id_is_high && conn->circ_id_type == CIRC_ID_TYPE_LOWER) {
info(LD_OR, "Got a low circuit ID from %s (%d); switching to "
"high circuit IDs.",
conn->nickname ? conn->nickname : "client", conn->s);
conn->circ_id_type = CIRC_ID_TYPE_HIGHER;
}
circ = circuit_get_by_circid_orconn(cell->circ_id, conn);
if (circ) {
routerinfo_t *router = router_get_by_digest(conn->identity_digest);
log_fn(LOG_PROTOCOL_WARN, LD_PROTOCOL,
"received CREATE cell (circID %d) for known circ. "
"Dropping (age %d).",
cell->circ_id, (int)(time(NULL) - conn->timestamp_created));
if (router)
log_fn(LOG_PROTOCOL_WARN, LD_PROTOCOL,
"Details: nickname '%s', platform '%s'.",
router->nickname, router->platform);
return;
}
circ = circuit_new(cell->circ_id, conn);
circ->purpose = CIRCUIT_PURPOSE_OR;
circuit_set_state(circ, CIRCUIT_STATE_ONIONSKIN_PENDING);
if (cell->command == CELL_CREATE) {
circ->onionskin = tor_malloc(ONIONSKIN_CHALLENGE_LEN);
memcpy(circ->onionskin, cell->payload, ONIONSKIN_CHALLENGE_LEN);
/* hand it off to the cpuworkers, and then return */
if (assign_to_cpuworker(NULL, CPUWORKER_TASK_ONION, circ) < 0) {
warn(LD_GENERAL,"Failed to hand off onionskin. Closing.");
circuit_mark_for_close(circ, END_CIRC_REASON_INTERNAL);
return;
}
debug(LD_OR,"success: handed off onionskin.");
} else {
/* This is a CREATE_FAST cell; we can handle it immediately without using
* a CPU worker.*/
char keys[CPATH_KEY_MATERIAL_LEN];
char reply[DIGEST_LEN*2];
tor_assert(cell->command == CELL_CREATE_FAST);
if (fast_server_handshake(cell->payload, reply, keys, sizeof(keys))<0) {
warn(LD_OR,"Failed to generate key material. Closing.");
circuit_mark_for_close(circ, END_CIRC_REASON_INTERNAL);
return;
}
if (onionskin_answer(circ, CELL_CREATED_FAST, reply, keys)<0) {
warn(LD_OR,"Failed to reply to CREATE_FAST cell. Closing.");
circuit_mark_for_close(circ, END_CIRC_REASON_INTERNAL);
return;
}
}
}
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/** Process a 'created' <b>cell</b> that just arrived from <b>conn</b>.
* Find the circuit
* that it's intended for. If we're not the origin of the circuit, package
* the 'created' cell in an 'extended' relay cell and pass it back. If we
* are the origin of the circuit, send it to circuit_finish_handshake() to
* finish processing keys, and then call circuit_send_next_onion_skin() to
* extend to the next hop in the circuit if necessary.
*/
static void
command_process_created_cell(cell_t *cell, connection_t *conn)
{
circuit_t *circ;
circ = circuit_get_by_circid_orconn(cell->circ_id, conn);
if (!circ) {
info(LD_OR,"(circID %d) unknown circ (probably got a destroy earlier). "
"Dropping.", cell->circ_id);
return;
}
if (circ->n_circ_id != cell->circ_id) {
log_fn(LOG_PROTOCOL_WARN,LD_PROTOCOL,
"got created cell from OPward? Closing.");
circuit_mark_for_close(circ, END_CIRC_REASON_TORPROTOCOL);
return;
}
if (CIRCUIT_IS_ORIGIN(circ)) { /* we're the OP. Handshake this. */
debug(LD_OR,"at OP. Finishing handshake.");
if (circuit_finish_handshake(circ, cell->command, cell->payload) < 0) {
warn(LD_OR,"circuit_finish_handshake failed.");
circuit_mark_for_close(circ, END_CIRC_AT_ORIGIN);
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return;
}
debug(LD_OR,"Moving to next skin.");
if (circuit_send_next_onion_skin(circ) < 0) {
info(LD_OR,"circuit_send_next_onion_skin failed.");
/* XXX push this circuit_close lower */
circuit_mark_for_close(circ, END_CIRC_AT_ORIGIN);
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return;
}
} else { /* pack it into an extended relay cell, and send it. */
debug(LD_OR,"Converting created cell to extended relay cell, sending.");
connection_edge_send_command(NULL, circ, RELAY_COMMAND_EXTENDED,
cell->payload, ONIONSKIN_REPLY_LEN, NULL);
}
}
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/** Process a 'relay' <b>cell</b> that just arrived from <b>conn</b>. Make sure
* it came in with a recognized circ_id. Pass it on to
* circuit_receive_relay_cell() for actual processing.
*/
static void
command_process_relay_cell(cell_t *cell, connection_t *conn)
{
circuit_t *circ;
int reason;
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circ = circuit_get_by_circid_orconn(cell->circ_id, conn);
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if (!circ) {
debug(LD_OR,"unknown circuit %d on connection from %s:%d. Dropping.",
cell->circ_id, conn->address, conn->port);
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return;
}
if (circ->state == CIRCUIT_STATE_ONIONSKIN_PENDING) {
log_fn(LOG_PROTOCOL_WARN,LD_PROTOCOL,"circuit in create_wait. Closing.");
circuit_mark_for_close(circ, END_CIRC_REASON_TORPROTOCOL);
return;
}
if (cell->circ_id == circ->p_circ_id) { /* it's an outgoing cell */
if ((reason = circuit_receive_relay_cell(cell, circ,
CELL_DIRECTION_OUT)) < 0) {
log_fn(LOG_PROTOCOL_WARN,LD_PROTOCOL,"circuit_receive_relay_cell "
"(forward) failed. Closing.");
circuit_mark_for_close(circ, -reason);
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return;
}
} else { /* it's an ingoing cell */
if ((reason = circuit_receive_relay_cell(cell, circ,
CELL_DIRECTION_IN)) < 0) {
log_fn(LOG_PROTOCOL_WARN,LD_PROTOCOL,"circuit_receive_relay_cell "
"(backward) failed. Closing.");
circuit_mark_for_close(circ, -reason);
return;
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}
}
}
/** Process a 'destroy' <b>cell</b> that just arrived from
* <b>conn</b>. Find the circ that it refers to (if any).
*
* If the circ is in state
* onionskin_pending, then call onion_pending_remove() to remove it
* from the pending onion list (note that if it's already being
* processed by the cpuworker, it won't be in the list anymore; but
* when the cpuworker returns it, the circuit will be gone, and the
* cpuworker response will be dropped).
*
* Then mark the circuit for close (which marks all edges for close,
* and passes the destroy cell onward if necessary).
*/
static void
command_process_destroy_cell(cell_t *cell, connection_t *conn)
{
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circuit_t *circ;
uint8_t reason;
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circ = circuit_get_by_circid_orconn(cell->circ_id, conn);
reason = (uint8_t)cell->payload[0];
if (!circ) {
info(LD_OR,"unknown circuit %d on connection from %s:%d. Dropping.",
cell->circ_id, conn->address, conn->port);
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return;
}
debug(LD_OR,"Received for circID %d.",cell->circ_id);
if (cell->circ_id == circ->p_circ_id) {
/* the destroy came from behind */
circuit_set_circid_orconn(circ, 0, NULL, P_CONN_CHANGED);
circuit_mark_for_close(circ, reason);
} else { /* the destroy came from ahead */
circuit_set_circid_orconn(circ, 0, NULL, N_CONN_CHANGED);
if (CIRCUIT_IS_ORIGIN(circ)) {
circuit_mark_for_close(circ, reason);
} else {
char payload[1];
debug(LD_OR, "Delivering 'truncated' back.");
payload[0] = (char)reason;
connection_edge_send_command(NULL, circ, RELAY_COMMAND_TRUNCATED,
payload, sizeof(payload), NULL);
}
}
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}