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// Copyright (c) 2015-2021 The Bitcoin Core developers
// Distributed under the MIT software license, see the accompanying
// file COPYING or http://www.opensource.org/licenses/mit-license.php.
/**
* Functionality for communicating with Tor.
*/
#ifndef BITCOIN_TORCONTROL_H
#define BITCOIN_TORCONTROL_H
#include <netaddress.h>
#include <util/fs.h>
#include <event2/util.h>
#include <cstdint>
#include <deque>
#include <functional>
#include <string>
#include <vector>
constexpr int DEFAULT_TOR_CONTROL_PORT = 9051;
extern const std::string DEFAULT_TOR_CONTROL;
static const bool DEFAULT_LISTEN_ONION = true;
void StartTorControl(CService onion_service_target);
void InterruptTorControl();
void StopTorControl();
CService DefaultOnionServiceTarget();
/** Reply from Tor, can be single or multi-line */
class TorControlReply
{
public:
TorControlReply() { Clear(); }
int code;
std::vector<std::string> lines;
void Clear()
{
code = 0;
lines.clear();
}
};
/** Low-level handling for Tor control connection.
* Speaks the SMTP-like protocol as defined in torspec/control-spec.txt
*/
class TorControlConnection
{
public:
typedef std::function<void(TorControlConnection&)> ConnectionCB;
typedef std::function<void(TorControlConnection &,const TorControlReply &)> ReplyHandlerCB;
/** Create a new TorControlConnection.
*/
explicit TorControlConnection(struct event_base *base);
~TorControlConnection();
/**
* Connect to a Tor control port.
* tor_control_center is address of the form host:port.
* connected is the handler that is called when connection is successfully established.
* disconnected is a handler that is called when the connection is broken.
* Return true on success.
*/
bool Connect(const std::string& tor_control_center, const ConnectionCB& connected, const ConnectionCB& disconnected);
/**
* Disconnect from Tor control port.
*/
void Disconnect();
/** Send a command, register a handler for the reply.
* A trailing CRLF is automatically added.
* Return true on success.
*/
bool Command(const std::string &cmd, const ReplyHandlerCB& reply_handler);
private:
/** Callback when ready for use */
std::function<void(TorControlConnection&)> connected;
/** Callback when connection lost */
std::function<void(TorControlConnection&)> disconnected;
/** Libevent event base */
struct event_base *base;
/** Connection to control socket */
struct bufferevent* b_conn{nullptr};
/** Message being received */
TorControlReply message;
/** Response handlers */
std::deque<ReplyHandlerCB> reply_handlers;
/** Libevent handlers: internal */
static void readcb(struct bufferevent *bev, void *ctx);
static void eventcb(struct bufferevent *bev, short what, void *ctx);
};
/****** Bitcoin specific TorController implementation ********/
/** Controller that connects to Tor control socket, authenticate, then create
* and maintain an ephemeral onion service.
*/
class TorController
{
public:
TorController(struct event_base* base, const std::string& tor_control_center, const CService& target);
TorController() : conn{nullptr} {
// Used for testing only.
}
~TorController();
/** Get name of file to store private key in */
fs::path GetPrivateKeyFile();
/** Reconnect, after getting disconnected */
void Reconnect();
private:
struct event_base* base;
const std::string m_tor_control_center;
TorControlConnection conn;
std::string private_key;
std::string service_id;
bool reconnect;
struct event *reconnect_ev = nullptr;
float reconnect_timeout;
CService service;
const CService m_target;
/** Cookie for SAFECOOKIE auth */
std::vector<uint8_t> cookie;
/** ClientNonce for SAFECOOKIE auth */
std::vector<uint8_t> clientNonce;
public:
/** Callback for GETINFO net/listeners/socks result */
void get_socks_cb(TorControlConnection& conn, const TorControlReply& reply);
/** Callback for ADD_ONION result */
void add_onion_cb(TorControlConnection& conn, const TorControlReply& reply);
/** Callback for AUTHENTICATE result */
void auth_cb(TorControlConnection& conn, const TorControlReply& reply);
/** Callback for AUTHCHALLENGE result */
void authchallenge_cb(TorControlConnection& conn, const TorControlReply& reply);
/** Callback for PROTOCOLINFO result */
void protocolinfo_cb(TorControlConnection& conn, const TorControlReply& reply);
/** Callback after successful connection */
void connected_cb(TorControlConnection& conn);
/** Callback after connection lost or failed connection attempt */
void disconnected_cb(TorControlConnection& conn);
/** Callback for reconnect timer */
static void reconnect_cb(evutil_socket_t fd, short what, void *arg);
};
#endif // BITCOIN_TORCONTROL_H
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