commit 81687f5bc975842bb4d251881b04e19092ab336e
Author: teor <teor(a)torproject.org>
Date: Tue Mar 17 17:18:40 2020 +1000
relay: Split out relay-only circuit building
Move the relay-only circuit building functions into a new file.
Part of 33633.
---
src/core/mainloop/cpuworker.c | 2 +-
src/core/or/circuitbuild.c | 233 +-----------------------------
src/core/or/circuitbuild.h | 19 ++-
src/core/or/command.c | 1 +
src/core/or/relay.c | 1 +
src/feature/relay/circuitbuild_relay.c | 253 +++++++++++++++++++++++++++++++++
src/feature/relay/circuitbuild_relay.h | 60 ++++++++
src/feature/relay/include.am | 2 +
8 files changed, 338 insertions(+), 233 deletions(-)
diff --git a/src/core/mainloop/cpuworker.c b/src/core/mainloop/cpuworker.c
index abd48f886..485ddb974 100644
--- a/src/core/mainloop/cpuworker.c
+++ b/src/core/mainloop/cpuworker.c
@@ -19,7 +19,6 @@
**/
#include "core/or/or.h"
#include "core/or/channel.h"
-#include "core/or/circuitbuild.h"
#include "core/or/circuitlist.h"
#include "core/or/connection_or.h"
#include "app/config/config.h"
@@ -27,6 +26,7 @@
#include "lib/crypt_ops/crypto_rand.h"
#include "lib/crypt_ops/crypto_util.h"
#include "core/or/onion.h"
+#include "feature/relay/circuitbuild_relay.h"
#include "feature/relay/onion_queue.h"
#include "feature/stats/rephist.h"
#include "feature/relay/router.h"
diff --git a/src/core/or/circuitbuild.c b/src/core/or/circuitbuild.c
index ea51d7b9b..0527548f2 100644
--- a/src/core/or/circuitbuild.c
+++ b/src/core/or/circuitbuild.c
@@ -21,8 +21,7 @@
* cells arrive, the client will invoke circuit_send_next_onion_skin() to send
* CREATE or RELAY_EXTEND cells.
*
- * On the server side, this module also handles the logic of responding to
- * RELAY_EXTEND requests, using circuit_extend().
+ * The server side is handled in feature/relay/circuitbuild_relay.c.
**/
#define CIRCUITBUILD_PRIVATE
@@ -35,7 +34,6 @@
#include "core/crypto/onion_crypto.h"
#include "core/crypto/onion_fast.h"
#include "core/crypto/onion_tap.h"
-#include "core/crypto/relay_crypto.h"
#include "core/mainloop/connection.h"
#include "core/mainloop/mainloop.h"
#include "core/or/channel.h"
@@ -84,13 +82,6 @@
#include "feature/nodelist/routerinfo_st.h"
#include "feature/nodelist/routerstatus_st.h"
-static channel_t * channel_connect_for_circuit(const tor_addr_t *addr,
- uint16_t port,
- const char *id_digest,
- const ed25519_public_key_t *ed_id);
-static int circuit_deliver_create_cell(circuit_t *circ,
- const create_cell_t *create_cell,
- int relayed);
static int circuit_send_first_onion_skin(origin_circuit_t *circ);
static int circuit_build_no_more_hops(origin_circuit_t *circ);
static int circuit_send_intermediate_onion_skin(origin_circuit_t *circ,
@@ -104,10 +95,10 @@ static const node_t *choose_good_middle_server(uint8_t purpose,
* and then calls command_setup_channel() to give it the right
* callbacks.
*/
-static channel_t *
+channel_t *
channel_connect_for_circuit(const tor_addr_t *addr, uint16_t port,
const char *id_digest,
- const ed25519_public_key_t *ed_id)
+ const struct ed25519_public_key_t *ed_id)
{
channel_t *chan;
@@ -707,8 +698,9 @@ circuit_n_chan_done(channel_t *chan, int status, int close_origin_circuits)
* gave us via an EXTEND cell, so we shouldn't worry if we don't understand
* it. Return -1 if we failed to find a suitable circid, else return 0.
*/
-static int
-circuit_deliver_create_cell(circuit_t *circ, const create_cell_t *create_cell,
+int
+circuit_deliver_create_cell(circuit_t *circ,
+ const struct create_cell_t *create_cell,
int relayed)
{
cell_t cell;
@@ -1166,164 +1158,6 @@ circuit_note_clock_jumped(int64_t seconds_elapsed, bool was_idle)
}
}
-/** Take the 'extend' <b>cell</b>, pull out addr/port plus the onion
- * skin and identity digest for the next hop. If we're already connected,
- * pass the onion skin to the next hop using a create cell; otherwise
- * launch a new OR connection, and <b>circ</b> will notice when the
- * connection succeeds or fails.
- *
- * Return -1 if we want to warn and tear down the circuit, else return 0.
- */
-int
-circuit_extend(cell_t *cell, circuit_t *circ)
-{
- channel_t *n_chan;
- relay_header_t rh;
- extend_cell_t ec;
- const char *msg = NULL;
- int should_launch = 0;
-
- if (circ->n_chan) {
- log_fn(LOG_PROTOCOL_WARN, LD_PROTOCOL,
- "n_chan already set. Bug/attack. Closing.");
- return -1;
- }
- if (circ->n_hop) {
- log_fn(LOG_PROTOCOL_WARN, LD_PROTOCOL,
- "conn to next hop already launched. Bug/attack. Closing.");
- return -1;
- }
-
- if (!server_mode(get_options())) {
- log_fn(LOG_PROTOCOL_WARN, LD_PROTOCOL,
- "Got an extend cell, but running as a client. Closing.");
- return -1;
- }
-
- relay_header_unpack(&rh, cell->payload);
-
- if (extend_cell_parse(&ec, rh.command,
- cell->payload+RELAY_HEADER_SIZE,
- rh.length) < 0) {
- log_fn(LOG_PROTOCOL_WARN, LD_PROTOCOL,
- "Can't parse extend cell. Closing circuit.");
- return -1;
- }
-
- if (!ec.orport_ipv4.port || tor_addr_is_null(&ec.orport_ipv4.addr)) {
- log_fn(LOG_PROTOCOL_WARN, LD_PROTOCOL,
- "Client asked me to extend to zero destination port or addr.");
- return -1;
- }
-
- if (tor_addr_is_internal(&ec.orport_ipv4.addr, 0) &&
- !get_options()->ExtendAllowPrivateAddresses) {
- log_fn(LOG_PROTOCOL_WARN, LD_PROTOCOL,
- "Client asked me to extend to a private address");
- return -1;
- }
-
- /* Check if they asked us for 0000..0000. We support using
- * an empty fingerprint for the first hop (e.g. for a bridge relay),
- * but we don't want to let clients send us extend cells for empty
- * fingerprints -- a) because it opens the user up to a mitm attack,
- * and b) because it lets an attacker force the relay to hold open a
- * new TLS connection for each extend request. */
- if (tor_digest_is_zero((const char*)ec.node_id)) {
- log_fn(LOG_PROTOCOL_WARN, LD_PROTOCOL,
- "Client asked me to extend without specifying an id_digest.");
- return -1;
- }
-
- /* Fill in ed_pubkey if it was not provided and we can infer it from
- * our networkstatus */
- if (ed25519_public_key_is_zero(&ec.ed_pubkey)) {
- const node_t *node = node_get_by_id((const char*)ec.node_id);
- const ed25519_public_key_t *node_ed_id = NULL;
- if (node &&
- node_supports_ed25519_link_authentication(node, 1) &&
- (node_ed_id = node_get_ed25519_id(node))) {
- ed25519_pubkey_copy(&ec.ed_pubkey, node_ed_id);
- }
- }
-
- /* Next, check if we're being asked to connect to the hop that the
- * extend cell came from. There isn't any reason for that, and it can
- * assist circular-path attacks. */
- if (tor_memeq(ec.node_id,
- TO_OR_CIRCUIT(circ)->p_chan->identity_digest,
- DIGEST_LEN)) {
- log_fn(LOG_PROTOCOL_WARN, LD_PROTOCOL,
- "Client asked me to extend back to the previous hop.");
- return -1;
- }
-
- /* Check the previous hop Ed25519 ID too */
- if (! ed25519_public_key_is_zero(&ec.ed_pubkey) &&
- ed25519_pubkey_eq(&ec.ed_pubkey,
- &TO_OR_CIRCUIT(circ)->p_chan->ed25519_identity)) {
- log_fn(LOG_PROTOCOL_WARN, LD_PROTOCOL,
- "Client asked me to extend back to the previous hop "
- "(by Ed25519 ID).");
- return -1;
- }
-
- n_chan = channel_get_for_extend((const char*)ec.node_id,
- &ec.ed_pubkey,
- &ec.orport_ipv4.addr,
- &msg,
- &should_launch);
-
- if (!n_chan) {
- log_debug(LD_CIRC|LD_OR,"Next router (%s): %s",
- fmt_addrport(&ec.orport_ipv4.addr,ec.orport_ipv4.port),
- msg?msg:"????");
-
- circ->n_hop = extend_info_new(NULL /*nickname*/,
- (const char*)ec.node_id,
- &ec.ed_pubkey,
- NULL, /*onion_key*/
- NULL, /*curve25519_key*/
- &ec.orport_ipv4.addr,
- ec.orport_ipv4.port);
-
- circ->n_chan_create_cell = tor_memdup(&ec.create_cell,
- sizeof(ec.create_cell));
-
- circuit_set_state(circ, CIRCUIT_STATE_CHAN_WAIT);
-
- if (should_launch) {
- /* we should try to open a connection */
- n_chan = channel_connect_for_circuit(&ec.orport_ipv4.addr,
- ec.orport_ipv4.port,
- (const char*)ec.node_id,
- &ec.ed_pubkey);
- if (!n_chan) {
- log_info(LD_CIRC,"Launching n_chan failed. Closing circuit.");
- circuit_mark_for_close(circ, END_CIRC_REASON_CONNECTFAILED);
- return 0;
- }
- log_debug(LD_CIRC,"connecting in progress (or finished). Good.");
- }
- /* return success. The onion/circuit/etc will be taken care of
- * automatically (may already have been) whenever n_chan reaches
- * OR_CONN_STATE_OPEN.
- */
- return 0;
- }
-
- tor_assert(!circ->n_hop); /* Connection is already established. */
- circ->n_chan = n_chan;
- log_debug(LD_CIRC,
- "n_chan is %s",
- channel_get_canonical_remote_descr(n_chan));
-
- if (circuit_deliver_create_cell(circ, &ec.create_cell, 1) < 0)
- return -1;
-
- return 0;
-}
-
/** A "created" cell <b>reply</b> came back to us on circuit <b>circ</b>.
* (The body of <b>reply</b> varies depending on what sort of handshake
* this is.)
@@ -1433,61 +1267,6 @@ circuit_truncated(origin_circuit_t *circ, int reason)
#endif /* 0 */
}
-/** Given a response payload and keys, initialize, then send a created
- * cell back.
- */
-int
-onionskin_answer(or_circuit_t *circ,
- const created_cell_t *created_cell,
- const char *keys, size_t keys_len,
- const uint8_t *rend_circ_nonce)
-{
- cell_t cell;
-
- tor_assert(keys_len == CPATH_KEY_MATERIAL_LEN);
-
- if (created_cell_format(&cell, created_cell) < 0) {
- log_warn(LD_BUG,"couldn't format created cell (type=%d, len=%d)",
- (int)created_cell->cell_type, (int)created_cell->handshake_len);
- return -1;
- }
- cell.circ_id = circ->p_circ_id;
-
- circuit_set_state(TO_CIRCUIT(circ), CIRCUIT_STATE_OPEN);
-
- log_debug(LD_CIRC,"init digest forward 0x%.8x, backward 0x%.8x.",
- (unsigned int)get_uint32(keys),
- (unsigned int)get_uint32(keys+20));
- if (relay_crypto_init(&circ->crypto, keys, keys_len, 0, 0)<0) {
- log_warn(LD_BUG,"Circuit initialization failed");
- return -1;
- }
-
- memcpy(circ->rend_circ_nonce, rend_circ_nonce, DIGEST_LEN);
-
- int used_create_fast = (created_cell->cell_type == CELL_CREATED_FAST);
-
- append_cell_to_circuit_queue(TO_CIRCUIT(circ),
- circ->p_chan, &cell, CELL_DIRECTION_IN, 0);
- log_debug(LD_CIRC,"Finished sending '%s' cell.",
- used_create_fast ? "created_fast" : "created");
-
- /* Ignore the local bit when ExtendAllowPrivateAddresses is set:
- * it violates the assumption that private addresses are local.
- * Also, many test networks run on local addresses, and
- * TestingTorNetwork sets ExtendAllowPrivateAddresses. */
- if ((!channel_is_local(circ->p_chan)
- || get_options()->ExtendAllowPrivateAddresses)
- && !channel_is_outgoing(circ->p_chan)) {
- /* record that we could process create cells from a non-local conn
- * that we didn't initiate; presumably this means that create cells
- * can reach us too. */
- router_orport_found_reachable();
- }
-
- return 0;
-}
-
/** Helper for new_route_len(). Choose a circuit length for purpose
* <b>purpose</b>: DEFAULT_ROUTE_LEN (+ 1 if someone else chose the
* exit). If someone else chose the exit, they could be colluding
diff --git a/src/core/or/circuitbuild.h b/src/core/or/circuitbuild.h
index 9a35c36ac..c66c0dc75 100644
--- a/src/core/or/circuitbuild.h
+++ b/src/core/or/circuitbuild.h
@@ -32,15 +32,10 @@ void circuit_n_chan_done(channel_t *chan, int status,
int circuit_timeout_want_to_count_circ(const origin_circuit_t *circ);
int circuit_send_next_onion_skin(origin_circuit_t *circ);
void circuit_note_clock_jumped(int64_t seconds_elapsed, bool was_idle);
-int circuit_extend(cell_t *cell, circuit_t *circ);
struct created_cell_t;
int circuit_finish_handshake(origin_circuit_t *circ,
const struct created_cell_t *created_cell);
int circuit_truncated(origin_circuit_t *circ, int reason);
-int onionskin_answer(or_circuit_t *circ,
- const struct created_cell_t *created_cell,
- const char *keys, size_t keys_len,
- const uint8_t *rend_circ_nonce);
MOCK_DECL(int, circuit_all_predicted_ports_handled, (time_t now,
int *need_uptime,
int *need_capacity));
@@ -76,6 +71,20 @@ const node_t *choose_good_entry_server(uint8_t purpose,
struct circuit_guard_state_t **guard_state_out);
void circuit_upgrade_circuits_from_guard_wait(void);
+struct ed25519_public_key_t;
+
+channel_t *
+channel_connect_for_circuit(const tor_addr_t *addr,
+ uint16_t port,
+ const char *id_digest,
+ const struct ed25519_public_key_t *ed_id);
+struct create_cell_t;
+
+int
+circuit_deliver_create_cell(circuit_t *circ,
+ const struct create_cell_t *create_cell,
+ int relayed);
+
#ifdef CIRCUITBUILD_PRIVATE
STATIC circid_t get_unique_circ_id_by_chan(channel_t *chan);
STATIC int new_route_len(uint8_t purpose, extend_info_t *exit_ei,
diff --git a/src/core/or/command.c b/src/core/or/command.c
index 9d946974b..8a1d2066c 100644
--- a/src/core/or/command.c
+++ b/src/core/or/command.c
@@ -54,6 +54,7 @@
#include "feature/nodelist/describe.h"
#include "feature/nodelist/nodelist.h"
#include "feature/nodelist/routerlist.h"
+#include "feature/relay/circuitbuild_relay.h"
#include "feature/relay/routermode.h"
#include "feature/stats/rephist.h"
#include "lib/crypt_ops/crypto_util.h"
diff --git a/src/core/or/relay.c b/src/core/or/relay.c
index 5ddabf347..00bbf77b9 100644
--- a/src/core/or/relay.c
+++ b/src/core/or/relay.c
@@ -66,6 +66,7 @@
#include "lib/crypt_ops/crypto_util.h"
#include "feature/dircommon/directory.h"
#include "feature/relay/dns.h"
+#include "feature/relay/circuitbuild_relay.h"
#include "feature/stats/geoip_stats.h"
#include "feature/hs/hs_cache.h"
#include "core/mainloop/mainloop.h"
diff --git a/src/feature/relay/circuitbuild_relay.c b/src/feature/relay/circuitbuild_relay.c
new file mode 100644
index 000000000..f167d0a8e
--- /dev/null
+++ b/src/feature/relay/circuitbuild_relay.c
@@ -0,0 +1,253 @@
+/* Copyright (c) 2001 Matej Pfajfar.
+ * Copyright (c) 2001-2004, Roger Dingledine.
+ * Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson.
+ * Copyright (c) 2007-2020, The Tor Project, Inc. */
+/* See LICENSE for licensing information */
+
+/**
+ * @file circuitbuild_relay.c
+ * @brief Implements the details of exteding circuits (by relaying extend
+ * cells as create cells, and answering create cells).
+ *
+ * On the server side, this module handles the logic of responding to
+ * RELAY_EXTEND requests, using circuit_extend() and onionskin_answer().
+ *
+ * The shared client and server code is in core/or/circuitbuild.c.
+ **/
+
+#include "orconfig.h"
+#include "feature/relay/circuitbuild_relay.h"
+
+#include "core/or/or.h"
+#include "app/config/config.h"
+
+#include "core/crypto/relay_crypto.h"
+
+#include "core/or/cell_st.h"
+#include "core/or/circuit_st.h"
+#include "core/or/extend_info_st.h"
+#include "core/or/or_circuit_st.h"
+
+#include "core/or/channel.h"
+#include "core/or/circuitbuild.h"
+#include "core/or/circuitlist.h"
+#include "core/or/onion.h"
+#include "core/or/relay.h"
+
+#include "feature/nodelist/nodelist.h"
+
+#include "feature/relay/routermode.h"
+#include "feature/relay/selftest.h"
+
+/** Take the 'extend' <b>cell</b>, pull out addr/port plus the onion
+ * skin and identity digest for the next hop. If we're already connected,
+ * pass the onion skin to the next hop using a create cell; otherwise
+ * launch a new OR connection, and <b>circ</b> will notice when the
+ * connection succeeds or fails.
+ *
+ * Return -1 if we want to warn and tear down the circuit, else return 0.
+ */
+int
+circuit_extend(struct cell_t *cell, struct circuit_t *circ)
+{
+ channel_t *n_chan;
+ relay_header_t rh;
+ extend_cell_t ec;
+ const char *msg = NULL;
+ int should_launch = 0;
+
+ if (circ->n_chan) {
+ log_fn(LOG_PROTOCOL_WARN, LD_PROTOCOL,
+ "n_chan already set. Bug/attack. Closing.");
+ return -1;
+ }
+ if (circ->n_hop) {
+ log_fn(LOG_PROTOCOL_WARN, LD_PROTOCOL,
+ "conn to next hop already launched. Bug/attack. Closing.");
+ return -1;
+ }
+
+ if (!server_mode(get_options())) {
+ log_fn(LOG_PROTOCOL_WARN, LD_PROTOCOL,
+ "Got an extend cell, but running as a client. Closing.");
+ return -1;
+ }
+
+ relay_header_unpack(&rh, cell->payload);
+
+ if (extend_cell_parse(&ec, rh.command,
+ cell->payload+RELAY_HEADER_SIZE,
+ rh.length) < 0) {
+ log_fn(LOG_PROTOCOL_WARN, LD_PROTOCOL,
+ "Can't parse extend cell. Closing circuit.");
+ return -1;
+ }
+
+ if (!ec.orport_ipv4.port || tor_addr_is_null(&ec.orport_ipv4.addr)) {
+ log_fn(LOG_PROTOCOL_WARN, LD_PROTOCOL,
+ "Client asked me to extend to zero destination port or addr.");
+ return -1;
+ }
+
+ if (tor_addr_is_internal(&ec.orport_ipv4.addr, 0) &&
+ !get_options()->ExtendAllowPrivateAddresses) {
+ log_fn(LOG_PROTOCOL_WARN, LD_PROTOCOL,
+ "Client asked me to extend to a private address");
+ return -1;
+ }
+
+ /* Check if they asked us for 0000..0000. We support using
+ * an empty fingerprint for the first hop (e.g. for a bridge relay),
+ * but we don't want to let clients send us extend cells for empty
+ * fingerprints -- a) because it opens the user up to a mitm attack,
+ * and b) because it lets an attacker force the relay to hold open a
+ * new TLS connection for each extend request. */
+ if (tor_digest_is_zero((const char*)ec.node_id)) {
+ log_fn(LOG_PROTOCOL_WARN, LD_PROTOCOL,
+ "Client asked me to extend without specifying an id_digest.");
+ return -1;
+ }
+
+ /* Fill in ed_pubkey if it was not provided and we can infer it from
+ * our networkstatus */
+ if (ed25519_public_key_is_zero(&ec.ed_pubkey)) {
+ const node_t *node = node_get_by_id((const char*)ec.node_id);
+ const ed25519_public_key_t *node_ed_id = NULL;
+ if (node &&
+ node_supports_ed25519_link_authentication(node, 1) &&
+ (node_ed_id = node_get_ed25519_id(node))) {
+ ed25519_pubkey_copy(&ec.ed_pubkey, node_ed_id);
+ }
+ }
+
+ /* Next, check if we're being asked to connect to the hop that the
+ * extend cell came from. There isn't any reason for that, and it can
+ * assist circular-path attacks. */
+ if (tor_memeq(ec.node_id,
+ TO_OR_CIRCUIT(circ)->p_chan->identity_digest,
+ DIGEST_LEN)) {
+ log_fn(LOG_PROTOCOL_WARN, LD_PROTOCOL,
+ "Client asked me to extend back to the previous hop.");
+ return -1;
+ }
+
+ /* Check the previous hop Ed25519 ID too */
+ if (! ed25519_public_key_is_zero(&ec.ed_pubkey) &&
+ ed25519_pubkey_eq(&ec.ed_pubkey,
+ &TO_OR_CIRCUIT(circ)->p_chan->ed25519_identity)) {
+ log_fn(LOG_PROTOCOL_WARN, LD_PROTOCOL,
+ "Client asked me to extend back to the previous hop "
+ "(by Ed25519 ID).");
+ return -1;
+ }
+
+ n_chan = channel_get_for_extend((const char*)ec.node_id,
+ &ec.ed_pubkey,
+ &ec.orport_ipv4.addr,
+ &msg,
+ &should_launch);
+
+ if (!n_chan) {
+ log_debug(LD_CIRC|LD_OR,"Next router (%s): %s",
+ fmt_addrport(&ec.orport_ipv4.addr,ec.orport_ipv4.port),
+ msg?msg:"????");
+
+ circ->n_hop = extend_info_new(NULL /*nickname*/,
+ (const char*)ec.node_id,
+ &ec.ed_pubkey,
+ NULL, /*onion_key*/
+ NULL, /*curve25519_key*/
+ &ec.orport_ipv4.addr,
+ ec.orport_ipv4.port);
+
+ circ->n_chan_create_cell = tor_memdup(&ec.create_cell,
+ sizeof(ec.create_cell));
+
+ circuit_set_state(circ, CIRCUIT_STATE_CHAN_WAIT);
+
+ if (should_launch) {
+ /* we should try to open a connection */
+ n_chan = channel_connect_for_circuit(&ec.orport_ipv4.addr,
+ ec.orport_ipv4.port,
+ (const char*)ec.node_id,
+ &ec.ed_pubkey);
+ if (!n_chan) {
+ log_info(LD_CIRC,"Launching n_chan failed. Closing circuit.");
+ circuit_mark_for_close(circ, END_CIRC_REASON_CONNECTFAILED);
+ return 0;
+ }
+ log_debug(LD_CIRC,"connecting in progress (or finished). Good.");
+ }
+ /* return success. The onion/circuit/etc will be taken care of
+ * automatically (may already have been) whenever n_chan reaches
+ * OR_CONN_STATE_OPEN.
+ */
+ return 0;
+ }
+
+ tor_assert(!circ->n_hop); /* Connection is already established. */
+ circ->n_chan = n_chan;
+ log_debug(LD_CIRC,
+ "n_chan is %s",
+ channel_get_canonical_remote_descr(n_chan));
+
+ if (circuit_deliver_create_cell(circ, &ec.create_cell, 1) < 0)
+ return -1;
+
+ return 0;
+}
+
+/** Given a response payload and keys, initialize, then send a created
+ * cell back.
+ */
+int
+onionskin_answer(struct or_circuit_t *circ,
+ const created_cell_t *created_cell,
+ const char *keys, size_t keys_len,
+ const uint8_t *rend_circ_nonce)
+{
+ cell_t cell;
+
+ tor_assert(keys_len == CPATH_KEY_MATERIAL_LEN);
+
+ if (created_cell_format(&cell, created_cell) < 0) {
+ log_warn(LD_BUG,"couldn't format created cell (type=%d, len=%d)",
+ (int)created_cell->cell_type, (int)created_cell->handshake_len);
+ return -1;
+ }
+ cell.circ_id = circ->p_circ_id;
+
+ circuit_set_state(TO_CIRCUIT(circ), CIRCUIT_STATE_OPEN);
+
+ log_debug(LD_CIRC,"init digest forward 0x%.8x, backward 0x%.8x.",
+ (unsigned int)get_uint32(keys),
+ (unsigned int)get_uint32(keys+20));
+ if (relay_crypto_init(&circ->crypto, keys, keys_len, 0, 0)<0) {
+ log_warn(LD_BUG,"Circuit initialization failed");
+ return -1;
+ }
+
+ memcpy(circ->rend_circ_nonce, rend_circ_nonce, DIGEST_LEN);
+
+ int used_create_fast = (created_cell->cell_type == CELL_CREATED_FAST);
+
+ append_cell_to_circuit_queue(TO_CIRCUIT(circ),
+ circ->p_chan, &cell, CELL_DIRECTION_IN, 0);
+ log_debug(LD_CIRC,"Finished sending '%s' cell.",
+ used_create_fast ? "created_fast" : "created");
+
+ /* Ignore the local bit when ExtendAllowPrivateAddresses is set:
+ * it violates the assumption that private addresses are local.
+ * Also, many test networks run on local addresses, and
+ * TestingTorNetwork sets ExtendAllowPrivateAddresses. */
+ if ((!channel_is_local(circ->p_chan)
+ || get_options()->ExtendAllowPrivateAddresses)
+ && !channel_is_outgoing(circ->p_chan)) {
+ /* record that we could process create cells from a non-local conn
+ * that we didn't initiate; presumably this means that create cells
+ * can reach us too. */
+ router_orport_found_reachable();
+ }
+
+ return 0;
+}
diff --git a/src/feature/relay/circuitbuild_relay.h b/src/feature/relay/circuitbuild_relay.h
new file mode 100644
index 000000000..decc28d3a
--- /dev/null
+++ b/src/feature/relay/circuitbuild_relay.h
@@ -0,0 +1,60 @@
+/* Copyright (c) 2001 Matej Pfajfar.
+ * Copyright (c) 2001-2004, Roger Dingledine.
+ * Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson.
+ * Copyright (c) 2007-2020, The Tor Project, Inc. */
+/* See LICENSE for licensing information */
+
+/**
+ * @file circuitbuild_relay.h
+ * @brief Header for feature/relay/circuitbuild_relay.c
+ **/
+
+#ifndef TOR_FEATURE_RELAY_CIRCUITBUILD_RELAY_H
+#define TOR_FEATURE_RELAY_CIRCUITBUILD_RELAY_H
+
+#include "lib/cc/torint.h"
+
+struct cell_t;
+struct created_cell_t;
+
+struct circuit_t;
+struct or_circuit_t;
+
+#ifdef HAVE_MODULE_RELAY
+
+int circuit_extend(struct cell_t *cell, struct circuit_t *circ);
+
+int onionskin_answer(struct or_circuit_t *circ,
+ const struct created_cell_t *created_cell,
+ const char *keys, size_t keys_len,
+ const uint8_t *rend_circ_nonce);
+
+#else
+
+static inline int
+circuit_extend(struct cell_t *cell, struct circuit_t *circ)
+{
+ (void)cell;
+ (void)circ;
+ tor_assert_nonfatal_unreached();
+ return -1;
+}
+
+static inline int
+onionskin_answer(struct or_circuit_t *circ,
+ const struct created_cell_t *created_cell,
+ const char *keys, size_t keys_len,
+ const uint8_t *rend_circ_nonce)
+{
+ (void)circ;
+ (void)created_cell;
+ (void)keys;
+ (void)keys_len;
+ (void)rend_circ_nonce;
+ tor_assert_nonfatal_unreached();
+ return -1;
+}
+
+#endif
+
+#endif /* !defined(TOR_FEATURE_RELAY_CIRCUITBUILD_RELAY_H) */
diff --git a/src/feature/relay/include.am b/src/feature/relay/include.am
index 813ddb8fb..654432c34 100644
--- a/src/feature/relay/include.am
+++ b/src/feature/relay/include.am
@@ -8,6 +8,7 @@ LIBTOR_APP_A_SOURCES += \
# ADD_C_FILE: INSERT SOURCES HERE.
MODULE_RELAY_SOURCES = \
+ src/feature/relay/circuitbuild_relay.c \
src/feature/relay/dns.c \
src/feature/relay/ext_orport.c \
src/feature/relay/routermode.c \
@@ -21,6 +22,7 @@ MODULE_RELAY_SOURCES = \
# ADD_C_FILE: INSERT HEADERS HERE.
noinst_HEADERS += \
+ src/feature/relay/circuitbuild_relay.h \
src/feature/relay/dns.h \
src/feature/relay/dns_structs.h \
src/feature/relay/ext_orport.h \
