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/* Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson.
* Copyright (c) 2007-2021, The Tor Project, Inc. */
/* See LICENSE for licensing information */
/**
* \file rendmid.c
* \brief Implement introductions points and rendezvous points.
**/
#include "core/or/or.h"
#include "core/or/channel.h"
#include "core/or/circuitlist.h"
#include "core/or/circuituse.h"
#include "app/config/config.h"
#include "lib/crypt_ops/crypto_cipher.h"
#include "core/or/dos.h"
#include "core/or/relay.h"
#include "feature/rend/rendmid.h"
#include "feature/hs/hs_circuitmap.h"
#include "feature/hs/hs_dos.h"
#include "feature/hs/hs_intropoint.h"
#include "core/or/or_circuit_st.h"
/** Process an ESTABLISH_RENDEZVOUS cell by setting the circuit's purpose and
* rendezvous cookie.
*/
int
rend_mid_establish_rendezvous(or_circuit_t *circ, const uint8_t *request,
size_t request_len)
{
char hexid[9];
int reason = END_CIRC_REASON_TORPROTOCOL;
log_info(LD_REND, "Received an ESTABLISH_RENDEZVOUS request on circuit %u",
(unsigned)circ->p_circ_id);
if (circ->base_.purpose != CIRCUIT_PURPOSE_OR) {
log_fn(LOG_PROTOCOL_WARN, LD_PROTOCOL,
"Tried to establish rendezvous on non-OR circuit with purpose %s",
circuit_purpose_to_string(circ->base_.purpose));
goto err;
}
/* Check if we are configured to defend ourselves from clients that
* attempt to establish rendezvous points directly to us. */
if (channel_is_client(circ->p_chan) &&
dos_should_refuse_single_hop_client()) {
/* Note it down for the heartbeat log purposes. */
dos_note_refuse_single_hop_client();
/* Silent drop so the client has to time out before moving on. */
return 0;
}
if (circ->base_.n_chan) {
log_fn(LOG_PROTOCOL_WARN, LD_PROTOCOL,
"Tried to establish rendezvous on non-edge circuit");
goto err;
}
if (request_len != REND_COOKIE_LEN) {
log_fn(LOG_PROTOCOL_WARN,
LD_PROTOCOL, "Invalid length on ESTABLISH_RENDEZVOUS.");
goto err;
}
if (hs_circuitmap_get_rend_circ_relay_side(request)) {
log_fn(LOG_PROTOCOL_WARN, LD_PROTOCOL,
"Duplicate rendezvous cookie in ESTABLISH_RENDEZVOUS.");
goto err;
}
/* Acknowledge the request. */
if (relay_send_command_from_edge(0,TO_CIRCUIT(circ),
RELAY_COMMAND_RENDEZVOUS_ESTABLISHED,
"", 0, NULL)<0) {
log_warn(LD_PROTOCOL, "Couldn't send RENDEZVOUS_ESTABLISHED cell.");
/* Stop right now, the circuit has been closed. */
return -1;
}
circuit_change_purpose(TO_CIRCUIT(circ), CIRCUIT_PURPOSE_REND_POINT_WAITING);
hs_circuitmap_register_rend_circ_relay_side(circ, request);
base16_encode(hexid,9,(char*)request,4);
log_info(LD_REND,
"Established rendezvous point on circuit %u for cookie %s",
(unsigned)circ->p_circ_id, hexid);
return 0;
err:
circuit_mark_for_close(TO_CIRCUIT(circ), reason);
return -1;
}
/** Process a RENDEZVOUS1 cell by looking up the correct rendezvous
* circuit by its relaying the cell's body in a RENDEZVOUS2 cell, and
* connecting the two circuits.
*/
int
rend_mid_rendezvous(or_circuit_t *circ, const uint8_t *request,
size_t request_len)
{
const or_options_t *options = get_options();
or_circuit_t *rend_circ;
char hexid[9];
int reason = END_CIRC_REASON_INTERNAL;
if (circ->base_.purpose != CIRCUIT_PURPOSE_OR || circ->base_.n_chan) {
log_fn(LOG_PROTOCOL_WARN, LD_PROTOCOL,
"Tried to complete rendezvous on non-OR or non-edge circuit %u.",
(unsigned)circ->p_circ_id);
reason = END_CIRC_REASON_TORPROTOCOL;
goto err;
}
if (request_len < REND_COOKIE_LEN) {
log_fn(LOG_PROTOCOL_WARN, LD_PROTOCOL,
"Rejecting RENDEZVOUS1 cell with bad length (%d) on circuit %u.",
(int)request_len, (unsigned)circ->p_circ_id);
reason = END_CIRC_REASON_TORPROTOCOL;
goto err;
}
base16_encode(hexid, sizeof(hexid), (const char*)request, 4);
log_info(LD_REND,
"Got request for rendezvous from circuit %u to cookie %s.",
(unsigned)circ->p_circ_id, hexid);
rend_circ = hs_circuitmap_get_rend_circ_relay_side(request);
if (!rend_circ) {
log_fn(LOG_PROTOCOL_WARN, LD_PROTOCOL,
"Rejecting RENDEZVOUS1 cell with unrecognized rendezvous cookie %s.",
hexid);
reason = END_CIRC_REASON_TORPROTOCOL;
goto err;
}
/* Statistics: Mark circuits as RP circuits */
if (options->HiddenServiceStatistics) {
/* `circ` is the RP <-> service circuit */
circ->circuit_carries_hs_traffic_stats = 1;
/* `rend_circ` is the client <-> RP circuit */
rend_circ->circuit_carries_hs_traffic_stats = 1;
}
/* Send the RENDEZVOUS2 cell to the client. */
if (relay_send_command_from_edge(0, TO_CIRCUIT(rend_circ),
RELAY_COMMAND_RENDEZVOUS2,
(char*)(request+REND_COOKIE_LEN),
request_len-REND_COOKIE_LEN, NULL)) {
log_warn(LD_GENERAL,
"Unable to send RENDEZVOUS2 cell to client on circuit %u.",
(unsigned)rend_circ->p_circ_id);
/* Stop right now, the circuit has been closed. */
return -1;
}
/* Join the circuits. */
log_info(LD_REND,
"Completing rendezvous: circuit %u joins circuit %u (cookie %s)",
(unsigned)circ->p_circ_id, (unsigned)rend_circ->p_circ_id, hexid);
circuit_change_purpose(TO_CIRCUIT(circ), CIRCUIT_PURPOSE_REND_ESTABLISHED);
circuit_change_purpose(TO_CIRCUIT(rend_circ),
CIRCUIT_PURPOSE_REND_ESTABLISHED);
hs_circuitmap_remove_circuit(TO_CIRCUIT(circ));
rend_circ->rend_splice = circ;
circ->rend_splice = rend_circ;
return 0;
err:
circuit_mark_for_close(TO_CIRCUIT(circ), reason);
return -1;
}
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