src/torcontrol.cpp

   1 // Copyright (c) 2015-2016 The Bitcoin Core developers
   2 // Distributed under the MIT software license, see the accompanying
   3 // file COPYING or http://www.opensource.org/licenses/mit-license.php.
   4
   5 #include "torcontrol.h"
   6 #include "utilstrencodings.h"
   7 #include "netbase.h"
   8 #include "net.h"
   9 #include "util.h"
  10 #include "crypto/hmac_sha256.h"
  11
  12 #include <vector>
  13 #include <deque>
  14 #include <set>
  15 #include <stdlib.h>
  16
  17 #include <boost/function.hpp>
  18 #include <boost/bind.hpp>
  19 #include <boost/signals2/signal.hpp>
  20 #include <boost/foreach.hpp>
  21 #include <boost/algorithm/string/predicate.hpp>
  22 #include <boost/algorithm/string/split.hpp>
  23 #include <boost/algorithm/string/classification.hpp>
  24 #include <boost/algorithm/string/replace.hpp>
  25
  26 #include <event2/bufferevent.h>
  27 #include <event2/buffer.h>
  28 #include <event2/util.h>
  29 #include <event2/event.h>
  30 #include <event2/thread.h>
  31
  32 /** Default control port */
  33 const std::string DEFAULT_TOR_CONTROL = "127.0.0.1:9051";
  34 /** Tor cookie size (from control-spec.txt) */
  35 static const int TOR_COOKIE_SIZE = 32;
  36 /** Size of client/server nonce for SAFECOOKIE */
  37 static const int TOR_NONCE_SIZE = 32;
  38 /** For computing serverHash in SAFECOOKIE */
  39 static const std::string TOR_SAFE_SERVERKEY = "Tor safe cookie authentication server-to-controller hash";
  40 /** For computing clientHash in SAFECOOKIE */
  41 static const std::string TOR_SAFE_CLIENTKEY = "Tor safe cookie authentication controller-to-server hash";
  42 /** Exponential backoff configuration - initial timeout in seconds */
  43 static const float RECONNECT_TIMEOUT_START = 1.0;
  44 /** Exponential backoff configuration - growth factor */
  45 static const float RECONNECT_TIMEOUT_EXP = 1.5;
  46 /** Maximum length for lines received on TorControlConnection.
  47  * tor-control-spec.txt mentions that there is explicitly no limit defined to line length,
  48  * this is belt-and-suspenders sanity limit to prevent memory exhaustion.
  49  */
  50 static const int MAX_LINE_LENGTH = 100000;
  51
  52 /****** Low-level TorControlConnection ********/
  53
  54 /** Reply from Tor, can be single or multi-line */
  55 class TorControlReply
  56 {
  57 public:
  58     TorControlReply() { Clear(); }
  59
  60     int code;
  61     std::vector<std::string> lines;
  62
  63     void Clear()
  64     {
  65         code = 0;
  66         lines.clear();
  67     }
  68 };
  69
  70 /** Low-level handling for Tor control connection.
  71  * Speaks the SMTP-like protocol as defined in torspec/control-spec.txt
  72  */
  73 class TorControlConnection
  74 {
  75 public:
  76     typedef boost::function<void(TorControlConnection&)> ConnectionCB;
  77     typedef boost::function<void(TorControlConnection &,const TorControlReply &)> ReplyHandlerCB;
  78
  79     /** Create a new TorControlConnection.
  80      */
  81     TorControlConnection(struct event_base *base);
  82     ~TorControlConnection();
  83
  84     /**
  85      * Connect to a Tor control port.
  86      * target is address of the form host:port.
  87      * connected is the handler that is called when connection is successfully established.
  88      * disconnected is a handler that is called when the connection is broken.
  89      * Return true on success.
  90      */
  91     bool Connect(const std::string &target, const ConnectionCB& connected, const ConnectionCB& disconnected);
  92
  93     /**
  94      * Disconnect from Tor control port.
  95      */
  96     bool Disconnect();
  97
  98     /** Send a command, register a handler for the reply.
  99      * A trailing CRLF is automatically added.
 100      * Return true on success.
 101      */
 102     bool Command(const std::string &cmd, const ReplyHandlerCB& reply_handler);
 103
 104     /** Response handlers for async replies */
 105     boost::signals2::signal<void(TorControlConnection &,const TorControlReply &)> async_handler;
 106 private:
 107     /** Callback when ready for use */
 108     boost::function<void(TorControlConnection&)> connected;
 109     /** Callback when connection lost */
 110     boost::function<void(TorControlConnection&)> disconnected;
 111     /** Libevent event base */
 112     struct event_base *base;
 113     /** Connection to control socket */
 114     struct bufferevent *b_conn;
 115     /** Message being received */
 116     TorControlReply message;
 117     /** Response handlers */
 118     std::deque<ReplyHandlerCB> reply_handlers;
 119
 120     /** Libevent handlers: internal */
 121     static void readcb(struct bufferevent *bev, void *ctx);
 122     static void eventcb(struct bufferevent *bev, short what, void *ctx);
 123 };
 124
 125 TorControlConnection::TorControlConnection(struct event_base *_base):
 126     base(_base), b_conn(0)
 127 {
 128 }
 129
 130 TorControlConnection::~TorControlConnection()
 131 {
 132     if (b_conn)
 133         bufferevent_free(b_conn);
 134 }
 135
 136 void TorControlConnection::readcb(struct bufferevent *bev, void *ctx)
 137 {
 138     TorControlConnection *self = (TorControlConnection*)ctx;
 139     struct evbuffer *input = bufferevent_get_input(bev);
 140     size_t n_read_out = 0;
 141     char *line;
 142     assert(input);
 143     //  If there is not a whole line to read, evbuffer_readln returns NULL
 144     while((line = evbuffer_readln(input, &n_read_out, EVBUFFER_EOL_CRLF)) != NULL)
 145     {
 146         std::string s(line, n_read_out);
 147         free(line);
 148         if (s.size() < 4) // Short line
 149             continue;
 150         // <status>(-|+| )<data><CRLF>
 151         self->message.code = atoi(s.substr(0,3));
 152         self->message.lines.push_back(s.substr(4));
 153         char ch = s[3]; // '-','+' or ' '
 154         if (ch == ' ') {
 155             // Final line, dispatch reply and clean up
 156             if (self->message.code >= 600) {
 157                 // Dispatch async notifications to async handler
 158                 // Synchronous and asynchronous messages are never interleaved
 159                 self->async_handler(*self, self->message);
 160             } else {
 161                 if (!self->reply_handlers.empty()) {
 162                     // Invoke reply handler with message
 163                     self->reply_handlers.front()(*self, self->message);
 164                     self->reply_handlers.pop_front();
 165                 } else {
 166                     LogPrint("tor", "tor: Received unexpected sync reply %i\n", self->message.code);
 167                 }
 168             }
 169             self->message.Clear();
 170         }
 171     }
 172     //  Check for size of buffer - protect against memory exhaustion with very long lines
 173     //  Do this after evbuffer_readln to make sure all full lines have been
 174     //  removed from the buffer. Everything left is an incomplete line.
 175     if (evbuffer_get_length(input) > MAX_LINE_LENGTH) {
 176         LogPrintf("tor: Disconnecting because MAX_LINE_LENGTH exceeded\n");
 177         self->Disconnect();
 178     }
 179 }
 180
 181 void TorControlConnection::eventcb(struct bufferevent *bev, short what, void *ctx)
 182 {
 183     TorControlConnection *self = (TorControlConnection*)ctx;
 184     if (what & BEV_EVENT_CONNECTED) {
 185         LogPrint("tor", "tor: Successfully connected!\n");
 186         self->connected(*self);
 187     } else if (what & (BEV_EVENT_EOF|BEV_EVENT_ERROR)) {
 188         if (what & BEV_EVENT_ERROR)
 189             LogPrint("tor", "tor: Error connecting to Tor control socket\n");
 190         else
 191             LogPrint("tor", "tor: End of stream\n");
 192         self->Disconnect();
 193         self->disconnected(*self);
 194     }
 195 }
 196
 197 bool TorControlConnection::Connect(const std::string &target, const ConnectionCB& _connected, const ConnectionCB&  _disconnected)
 198 {
 199     if (b_conn)
 200         Disconnect();
 201     // Parse target address:port
 202     struct sockaddr_storage connect_to_addr;
 203     int connect_to_addrlen = sizeof(connect_to_addr);
 204     if (evutil_parse_sockaddr_port(target.c_str(),
 205         (struct sockaddr*)&connect_to_addr, &connect_to_addrlen)<0) {
 206         LogPrintf("tor: Error parsing socket address %s\n", target);
 207         return false;
 208     }
 209
 210     // Create a new socket, set up callbacks and enable notification bits
 211     b_conn = bufferevent_socket_new(base, -1, BEV_OPT_CLOSE_ON_FREE);
 212     if (!b_conn)
 213         return false;
 214     bufferevent_setcb(b_conn, TorControlConnection::readcb, NULL, TorControlConnection::eventcb, this);
 215     bufferevent_enable(b_conn, EV_READ|EV_WRITE);
 216     this->connected = _connected;
 217     this->disconnected = _disconnected;
 218
 219     // Finally, connect to target
 220     if (bufferevent_socket_connect(b_conn, (struct sockaddr*)&connect_to_addr, connect_to_addrlen) < 0) {
 221         LogPrintf("tor: Error connecting to address %s\n", target);
 222         return false;
 223     }
 224     return true;
 225 }
 226
 227 bool TorControlConnection::Disconnect()
 228 {
 229     if (b_conn)
 230         bufferevent_free(b_conn);
 231     b_conn = 0;
 232     return true;
 233 }
 234
 235 bool TorControlConnection::Command(const std::string &cmd, const ReplyHandlerCB& reply_handler)
 236 {
 237     if (!b_conn)
 238         return false;
 239     struct evbuffer *buf = bufferevent_get_output(b_conn);
 240     if (!buf)
 241         return false;
 242     evbuffer_add(buf, cmd.data(), cmd.size());
 243     evbuffer_add(buf, "\r\n", 2);
 244     reply_handlers.push_back(reply_handler);
 245     return true;
 246 }
 247
 248 /****** General parsing utilities ********/
 249
 250 /* Split reply line in the form 'AUTH METHODS=...' into a type
 251  * 'AUTH' and arguments 'METHODS=...'.
 252  */
 253 static std::pair<std::string,std::string> SplitTorReplyLine(const std::string &s)
 254 {
 255     size_t ptr=0;
 256     std::string type;
 257     while (ptr < s.size() && s[ptr] != ' ') {
 258         type.push_back(s[ptr]);
 259         ++ptr;
 260     }
 261     if (ptr < s.size())
 262         ++ptr; // skip ' '
 263     return make_pair(type, s.substr(ptr));
 264 }
 265
 266 /** Parse reply arguments in the form 'METHODS=COOKIE,SAFECOOKIE COOKIEFILE=".../control_auth_cookie"'.
 267  */
 268 static std::map<std::string,std::string> ParseTorReplyMapping(const std::string &s)
 269 {
 270     std::map<std::string,std::string> mapping;
 271     size_t ptr=0;
 272     while (ptr < s.size()) {
 273         std::string key, value;
 274         while (ptr < s.size() && s[ptr] != '=') {
 275             key.push_back(s[ptr]);
 276             ++ptr;
 277         }
 278         if (ptr == s.size()) // unexpected end of line
 279             return std::map<std::string,std::string>();
 280         ++ptr; // skip '='
 281         if (ptr < s.size() && s[ptr] == '"') { // Quoted string
 282             ++ptr; // skip '='
 283             bool escape_next = false;
 284             while (ptr < s.size() && (!escape_next && s[ptr] != '"')) {
 285                 escape_next = (s[ptr] == '\\');
 286                 value.push_back(s[ptr]);
 287                 ++ptr;
 288             }
 289             if (ptr == s.size()) // unexpected end of line
 290                 return std::map<std::string,std::string>();
 291             ++ptr; // skip closing '"'
 292             /* TODO: unescape value - according to the spec this depends on the
 293              * context, some strings use C-LogPrintf style escape codes, some
 294              * don't. So may be better handled at the call site.
 295              */
 296         } else { // Unquoted value. Note that values can contain '=' at will, just no spaces
 297             while (ptr < s.size() && s[ptr] != ' ') {
 298                 value.push_back(s[ptr]);
 299                 ++ptr;
 300             }
 301         }
 302         if (ptr < s.size() && s[ptr] == ' ')
 303             ++ptr; // skip ' ' after key=value
 304         mapping[key] = value;
 305     }
 306     return mapping;
 307 }
 308
 309 /** Read full contents of a file and return them in a std::string.
 310  * Returns a pair <status, string>.
 311  * If an error occurred, status will be false, otherwise status will be true and the data will be returned in string.
 312  *
 313  * @param maxsize Puts a maximum size limit on the file that is read. If the file is larger than this, truncated data
 314  *         (with len > maxsize) will be returned.
 315  */
 316 static std::pair<bool,std::string> ReadBinaryFile(const std::string &filename, size_t maxsize=std::numeric_limits<size_t>::max())
 317 {
 318     FILE *f = fopen(filename.c_str(), "rb");
 319     if (f == NULL)
 320         return std::make_pair(false,"");
 321     std::string retval;
 322     char buffer[128];
 323     size_t n;
 324     while ((n=fread(buffer, 1, sizeof(buffer), f)) > 0) {
 325         retval.append(buffer, buffer+n);
 326         if (retval.size() > maxsize)
 327             break;
 328     }
 329     fclose(f);
 330     return std::make_pair(true,retval);
 331 }
 332
 333 /** Write contents of std::string to a file.
 334  * @return true on success.
 335  */
 336 static bool WriteBinaryFile(const std::string &filename, const std::string &data)
 337 {
 338     FILE *f = fopen(filename.c_str(), "wb");
 339     if (f == NULL)
 340         return false;
 341     if (fwrite(data.data(), 1, data.size(), f) != data.size()) {
 342         fclose(f);
 343         return false;
 344     }
 345     fclose(f);
 346     return true;
 347 }
 348
 349 /****** Bitcoin specific TorController implementation ********/
 350
 351 /** Controller that connects to Tor control socket, authenticate, then create
 352  * and maintain a ephemeral hidden service.
 353  */
 354 class TorController
 355 {
 356 public:
 357     TorController(struct event_base* base, const std::string& target);
 358     ~TorController();
 359
 360     /** Get name fo file to store private key in */
 361     std::string GetPrivateKeyFile();
 362
 363     /** Reconnect, after getting disconnected */
 364     void Reconnect();
 365 private:
 366     struct event_base* base;
 367     std::string target;
 368     TorControlConnection conn;
 369     std::string private_key;
 370     std::string service_id;
 371     bool reconnect;
 372     struct event *reconnect_ev;
 373     float reconnect_timeout;
 374     CService service;
 375     /** Cookie for SAFECOOKIE auth */
 376     std::vector<uint8_t> cookie;
 377     /** ClientNonce for SAFECOOKIE auth */
 378     std::vector<uint8_t> clientNonce;
 379
 380     /** Callback for ADD_ONION result */
 381     void add_onion_cb(TorControlConnection& conn, const TorControlReply& reply);
 382     /** Callback for AUTHENTICATE result */
 383     void auth_cb(TorControlConnection& conn, const TorControlReply& reply);
 384     /** Callback for AUTHCHALLENGE result */
 385     void authchallenge_cb(TorControlConnection& conn, const TorControlReply& reply);
 386     /** Callback for PROTOCOLINFO result */
 387     void protocolinfo_cb(TorControlConnection& conn, const TorControlReply& reply);
 388     /** Callback after successful connection */
 389     void connected_cb(TorControlConnection& conn);
 390     /** Callback after connection lost or failed connection attempt */
 391     void disconnected_cb(TorControlConnection& conn);
 392
 393     /** Callback for reconnect timer */
 394     static void reconnect_cb(evutil_socket_t fd, short what, void *arg);
 395 };
 396
 397 TorController::TorController(struct event_base* _base, const std::string& _target):
 398     base(_base),
 399     target(_target), conn(base), reconnect(true), reconnect_ev(0),
 400     reconnect_timeout(RECONNECT_TIMEOUT_START)
 401 {
 402     reconnect_ev = event_new(base, -1, 0, reconnect_cb, this);
 403     if (!reconnect_ev)
 404         LogPrintf("tor: Failed to create event for reconnection: out of memory?\n");
 405     // Start connection attempts immediately
 406     if (!conn.Connect(_target, boost::bind(&TorController::connected_cb, this, _1),
 407          boost::bind(&TorController::disconnected_cb, this, _1) )) {
 408         LogPrintf("tor: Initiating connection to Tor control port %s failed\n", _target);
 409     }
 410     // Read service private key if cached
 411     std::pair<bool,std::string> pkf = ReadBinaryFile(GetPrivateKeyFile());
 412     if (pkf.first) {
 413         LogPrint("tor", "tor: Reading cached private key from %s\n", GetPrivateKeyFile());
 414         private_key = pkf.second;
 415     }
 416 }
 417
 418 TorController::~TorController()
 419 {
 420     if (reconnect_ev) {
 421         event_free(reconnect_ev);
 422         reconnect_ev = 0;
 423     }
 424     if (service.IsValid()) {
 425         RemoveLocal(service);
 426     }
 427 }
 428
 429 void TorController::add_onion_cb(TorControlConnection& _conn, const TorControlReply& reply)
 430 {
 431     if (reply.code == 250) {
 432         LogPrint("tor", "tor: ADD_ONION successful\n");
 433         BOOST_FOREACH(const std::string &s, reply.lines) {
 434             std::map<std::string,std::string> m = ParseTorReplyMapping(s);
 435             std::map<std::string,std::string>::iterator i;
 436             if ((i = m.find("ServiceID")) != m.end())
 437                 service_id = i->second;
 438             if ((i = m.find("PrivateKey")) != m.end())
 439                 private_key = i->second;
 440         }
 441         service = LookupNumeric(std::string(service_id+".onion").c_str(), GetListenPort());
 442         LogPrintf("tor: Got service ID %s, advertising service %s\n", service_id, service.ToString());
 443         if (WriteBinaryFile(GetPrivateKeyFile(), private_key)) {
 444             LogPrint("tor", "tor: Cached service private key to %s\n", GetPrivateKeyFile());
 445         } else {
 446             LogPrintf("tor: Error writing service private key to %s\n", GetPrivateKeyFile());
 447         }
 448         AddLocal(service, LOCAL_MANUAL);
 449         // ... onion requested - keep connection open
 450     } else if (reply.code == 510) { // 510 Unrecognized command
 451         LogPrintf("tor: Add onion failed with unrecognized command (You probably need to upgrade Tor)\n");
 452     } else {
 453         LogPrintf("tor: Add onion failed; error code %d\n", reply.code);
 454     }
 455 }
 456
 457 void TorController::auth_cb(TorControlConnection& _conn, const TorControlReply& reply)
 458 {
 459     if (reply.code == 250) {
 460         LogPrint("tor", "tor: Authentication successful\n");
 461
 462         // Now that we know Tor is running setup the proxy for onion addresses
 463         // if -onion isn't set to something else.
 464         if (GetArg("-onion", "") == "") {
 465             CService resolved(LookupNumeric("127.0.0.1", 9050));
 466             proxyType addrOnion = proxyType(resolved, true);
 467             SetProxy(NET_TOR, addrOnion);
 468             SetLimited(NET_TOR, false);
 469         }
 470
 471         // Finally - now create the service
 472         if (private_key.empty()) // No private key, generate one
 473             private_key = "NEW:RSA1024"; // Explicitly request RSA1024 - see issue #9214
 474         // Request hidden service, redirect port.
 475         // Note that the 'virtual' port doesn't have to be the same as our internal port, but this is just a convenient
 476         // choice.  TODO; refactor the shutdown sequence some day.
 477         _conn.Command(strprintf("ADD_ONION %s Port=%i,127.0.0.1:%i", private_key, GetListenPort(), GetListenPort()),
 478             boost::bind(&TorController::add_onion_cb, this, _1, _2));
 479     } else {
 480         LogPrintf("tor: Authentication failed\n");
 481     }
 482 }
 483
 484 /** Compute Tor SAFECOOKIE response.
 485  *
 486  *    ServerHash is computed as:
 487  *      HMAC-SHA256("Tor safe cookie authentication server-to-controller hash",
 488  *                  CookieString | ClientNonce | ServerNonce)
 489  *    (with the HMAC key as its first argument)
 490  *
 491  *    After a controller sends a successful AUTHCHALLENGE command, the
 492  *    next command sent on the connection must be an AUTHENTICATE command,
 493  *    and the only authentication string which that AUTHENTICATE command
 494  *    will accept is:
 495  *
 496  *      HMAC-SHA256("Tor safe cookie authentication controller-to-server hash",
 497  *                  CookieString | ClientNonce | ServerNonce)
 498  *
 499  */
 500 static std::vector<uint8_t> ComputeResponse(const std::string &key, const std::vector<uint8_t> &cookie,  const std::vector<uint8_t> &clientNonce, const std::vector<uint8_t> &serverNonce)
 501 {
 502     CHMAC_SHA256 computeHash((const uint8_t*)key.data(), key.size());
 503     std::vector<uint8_t> computedHash(CHMAC_SHA256::OUTPUT_SIZE, 0);
 504     computeHash.Write(cookie.data(), cookie.size());
 505     computeHash.Write(clientNonce.data(), clientNonce.size());
 506     computeHash.Write(serverNonce.data(), serverNonce.size());
 507     computeHash.Finalize(computedHash.data());
 508     return computedHash;
 509 }
 510
 511 void TorController::authchallenge_cb(TorControlConnection& _conn, const TorControlReply& reply)
 512 {
 513     if (reply.code == 250) {
 514         LogPrint("tor", "tor: SAFECOOKIE authentication challenge successful\n");
 515         std::pair<std::string,std::string> l = SplitTorReplyLine(reply.lines[0]);
 516         if (l.first == "AUTHCHALLENGE") {
 517             std::map<std::string,std::string> m = ParseTorReplyMapping(l.second);
 518             std::vector<uint8_t> serverHash = ParseHex(m["SERVERHASH"]);
 519             std::vector<uint8_t> serverNonce = ParseHex(m["SERVERNONCE"]);
 520             LogPrint("tor", "tor: AUTHCHALLENGE ServerHash %s ServerNonce %s\n", HexStr(serverHash), HexStr(serverNonce));
 521             if (serverNonce.size() != 32) {
 522                 LogPrintf("tor: ServerNonce is not 32 bytes, as required by spec\n");
 523                 return;
 524             }
 525
 526             std::vector<uint8_t> computedServerHash = ComputeResponse(TOR_SAFE_SERVERKEY, cookie, clientNonce, serverNonce);
 527             if (computedServerHash != serverHash) {
 528                 LogPrintf("tor: ServerHash %s does not match expected ServerHash %s\n", HexStr(serverHash), HexStr(computedServerHash));
 529                 return;
 530             }
 531
 532             std::vector<uint8_t> computedClientHash = ComputeResponse(TOR_SAFE_CLIENTKEY, cookie, clientNonce, serverNonce);
 533             _conn.Command("AUTHENTICATE " + HexStr(computedClientHash), boost::bind(&TorController::auth_cb, this, _1, _2));
 534         } else {
 535             LogPrintf("tor: Invalid reply to AUTHCHALLENGE\n");
 536         }
 537     } else {
 538         LogPrintf("tor: SAFECOOKIE authentication challenge failed\n");
 539     }
 540 }
 541
 542 void TorController::protocolinfo_cb(TorControlConnection& _conn, const TorControlReply& reply)
 543 {
 544     if (reply.code == 250) {
 545         std::set<std::string> methods;
 546         std::string cookiefile;
 547         /*
 548          * 250-AUTH METHODS=COOKIE,SAFECOOKIE COOKIEFILE="/home/x/.tor/control_auth_cookie"
 549          * 250-AUTH METHODS=NULL
 550          * 250-AUTH METHODS=HASHEDPASSWORD
 551          */
 552         BOOST_FOREACH(const std::string &s, reply.lines) {
 553             std::pair<std::string,std::string> l = SplitTorReplyLine(s);
 554             if (l.first == "AUTH") {
 555                 std::map<std::string,std::string> m = ParseTorReplyMapping(l.second);
 556                 std::map<std::string,std::string>::iterator i;
 557                 if ((i = m.find("METHODS")) != m.end())
 558                     boost::split(methods, i->second, boost::is_any_of(","));
 559                 if ((i = m.find("COOKIEFILE")) != m.end())
 560                     cookiefile = i->second;
 561             } else if (l.first == "VERSION") {
 562                 std::map<std::string,std::string> m = ParseTorReplyMapping(l.second);
 563                 std::map<std::string,std::string>::iterator i;
 564                 if ((i = m.find("Tor")) != m.end()) {
 565                     LogPrint("tor", "tor: Connected to Tor version %s\n", i->second);
 566                 }
 567             }
 568         }
 569         BOOST_FOREACH(const std::string &s, methods) {
 570             LogPrint("tor", "tor: Supported authentication method: %s\n", s);
 571         }
 572         // Prefer NULL, otherwise SAFECOOKIE. If a password is provided, use HASHEDPASSWORD
 573         /* Authentication:
 574          *   cookie:   hex-encoded ~/.tor/control_auth_cookie
 575          *   password: "password"
 576          */
 577         std::string torpassword = GetArg("-torpassword", "");
 578         if (!torpassword.empty()) {
 579             if (methods.count("HASHEDPASSWORD")) {
 580                 LogPrint("tor", "tor: Using HASHEDPASSWORD authentication\n");
 581                 boost::replace_all(torpassword, "\"", "\\\"");
 582                 _conn.Command("AUTHENTICATE \"" + torpassword + "\"", boost::bind(&TorController::auth_cb, this, _1, _2));
 583             } else {
 584                 LogPrintf("tor: Password provided with -torpassword, but HASHEDPASSWORD authentication is not available\n");
 585             }
 586         } else if (methods.count("NULL")) {
 587             LogPrint("tor", "tor: Using NULL authentication\n");
 588             _conn.Command("AUTHENTICATE", boost::bind(&TorController::auth_cb, this, _1, _2));
 589         } else if (methods.count("SAFECOOKIE")) {
 590             // Cookie: hexdump -e '32/1 "%02x""\n"'  ~/.tor/control_auth_cookie
 591             LogPrint("tor", "tor: Using SAFECOOKIE authentication, reading cookie authentication from %s\n", cookiefile);
 592             std::pair<bool,std::string> status_cookie = ReadBinaryFile(cookiefile, TOR_COOKIE_SIZE);
 593             if (status_cookie.first && status_cookie.second.size() == TOR_COOKIE_SIZE) {
 594                 // _conn.Command("AUTHENTICATE " + HexStr(status_cookie.second), boost::bind(&TorController::auth_cb, this, _1, _2));
 595                 cookie = std::vector<uint8_t>(status_cookie.second.begin(), status_cookie.second.end());
 596                 clientNonce = std::vector<uint8_t>(TOR_NONCE_SIZE, 0);
 597                 GetRandBytes(&clientNonce[0], TOR_NONCE_SIZE);
 598                 _conn.Command("AUTHCHALLENGE SAFECOOKIE " + HexStr(clientNonce), boost::bind(&TorController::authchallenge_cb, this, _1, _2));
 599             } else {
 600                 if (status_cookie.first) {
 601                     LogPrintf("tor: Authentication cookie %s is not exactly %i bytes, as is required by the spec\n", cookiefile, TOR_COOKIE_SIZE);
 602                 } else {
 603                     LogPrintf("tor: Authentication cookie %s could not be opened (check permissions)\n", cookiefile);
 604                 }
 605             }
 606         } else if (methods.count("HASHEDPASSWORD")) {
 607             LogPrintf("tor: The only supported authentication mechanism left is password, but no password provided with -torpassword\n");
 608         } else {
 609             LogPrintf("tor: No supported authentication method\n");
 610         }
 611     } else {
 612         LogPrintf("tor: Requesting protocol info failed\n");
 613     }
 614 }
 615
 616 void TorController::connected_cb(TorControlConnection& _conn)
 617 {
 618     reconnect_timeout = RECONNECT_TIMEOUT_START;
 619     // First send a PROTOCOLINFO command to figure out what authentication is expected
 620     if (!_conn.Command("PROTOCOLINFO 1", boost::bind(&TorController::protocolinfo_cb, this, _1, _2)))
 621         LogPrintf("tor: Error sending initial protocolinfo command\n");
 622 }
 623
 624 void TorController::disconnected_cb(TorControlConnection& _conn)
 625 {
 626     // Stop advertising service when disconnected
 627     if (service.IsValid())
 628         RemoveLocal(service);
 629     service = CService();
 630     if (!reconnect)
 631         return;
 632
 633     LogPrint("tor", "tor: Not connected to Tor control port %s, trying to reconnect\n", target);
 634
 635     // Single-shot timer for reconnect. Use exponential backoff.
 636     struct timeval time = MillisToTimeval(int64_t(reconnect_timeout * 1000.0));
 637     if (reconnect_ev)
 638         event_add(reconnect_ev, &time);
 639     reconnect_timeout *= RECONNECT_TIMEOUT_EXP;
 640 }
 641
 642 void TorController::Reconnect()
 643 {
 644     /* Try to reconnect and reestablish if we get booted - for example, Tor
 645      * may be restarting.
 646      */
 647     if (!conn.Connect(target, boost::bind(&TorController::connected_cb, this, _1),
 648          boost::bind(&TorController::disconnected_cb, this, _1) )) {
 649         LogPrintf("tor: Re-initiating connection to Tor control port %s failed\n", target);
 650     }
 651 }
 652
 653 std::string TorController::GetPrivateKeyFile()
 654 {
 655     return (GetDataDir() / "onion_private_key").string();
 656 }
 657
 658 void TorController::reconnect_cb(evutil_socket_t fd, short what, void *arg)
 659 {
 660     TorController *self = (TorController*)arg;
 661     self->Reconnect();
 662 }
 663
 664 /****** Thread ********/
 665 static struct event_base *gBase;
 666 static boost::thread torControlThread;
 667
 668 static void TorControlThread()
 669 {
 670     TorController ctrl(gBase, GetArg("-torcontrol", DEFAULT_TOR_CONTROL));
 671
 672     event_base_dispatch(gBase);
 673 }
 674
 675 void StartTorControl(boost::thread_group& threadGroup, CScheduler& scheduler)
 676 {
 677     assert(!gBase);
 678 #ifdef WIN32
 679     evthread_use_windows_threads();
 680 #else
 681     evthread_use_pthreads();
 682 #endif
 683     gBase = event_base_new();
 684     if (!gBase) {
 685         LogPrintf("tor: Unable to create event_base\n");
 686         return;
 687     }
 688
 689     torControlThread = boost::thread(boost::bind(&TraceThread<void (*)()>, "torcontrol", &TorControlThread));
 690 }
 691
 692 void InterruptTorControl()
 693 {
 694     if (gBase) {
 695         LogPrintf("tor: Thread interrupt\n");
 696         event_base_loopbreak(gBase);
 697     }
 698 }
 699
 700 void StopTorControl()
 701 {
 702     if (gBase) {
 703         torControlThread.join();
 704         event_base_free(gBase);
 705         gBase = 0;
 706     }
 707 }
 708