text: #include "torcontrol.h"
  #include "utilstrencodings.h"
  #include "net.h"
  #include "util.h"
  #include "crypto/hmac_sha256.h"
  
  #include <vector>
  #include <deque>
  #include <set>
  #include <stdlib.h>
  
  #include <boost/function.hpp>
  #include <boost/bind.hpp>
  #include <boost/signals2/signal.hpp>
  #include <boost/foreach.hpp>
  #include <boost/algorithm/string/predicate.hpp>
  #include <boost/algorithm/string/split.hpp>
  #include <boost/algorithm/string/classification.hpp>
  #include <boost/algorithm/string/replace.hpp>
  
  #include <event2/bufferevent.h>
  #include <event2/buffer.h>
  #include <event2/util.h>
  #include <event2/event.h>
  #include <event2/thread.h>
  
  /** Default control port */
  const std::string DEFAULT_TOR_CONTROL = "127.0.0.1:9051";
  /** Tor cookie size (from control-spec.txt) */
  static const int TOR_COOKIE_SIZE = 32;
  /** Size of client/server nonce for SAFECOOKIE */
  static const int TOR_NONCE_SIZE = 32;
  /** For computing serverHash in SAFECOOKIE */
  static const std::string TOR_SAFE_SERVERKEY = "Tor safe cookie authentication server-to-controller hash";
  /** For computing clientHash in SAFECOOKIE */
  static const std::string TOR_SAFE_CLIENTKEY = "Tor safe cookie authentication controller-to-server hash";
  /** Exponential backoff configuration - initial timeout in seconds */
  static const float RECONNECT_TIMEOUT_START = 1.0;
  /** Exponential backoff configuration - growth factor */
  static const float RECONNECT_TIMEOUT_EXP = 1.5;
  /** Maximum length for lines received on TorControlConnection.
   * tor-control-spec.txt mentions that there is explicitly no limit defined to line length,
   * this is belt-and-suspenders sanity limit to prevent memory exhaustion.
   */
  static const int MAX_LINE_LENGTH = 100000;
  
  /****** Low-level TorControlConnection ********/
  
  /** 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 boost::function<void(TorControlConnection&)> ConnectionCB;
      typedef boost::function<void(TorControlConnection &,const TorControlReply &)> ReplyHandlerCB;
  
      /** Create a new TorControlConnection.
       */
      TorControlConnection(struct event_base *base);
      ~TorControlConnection();
  
      /**
       * Connect to a Tor control port.
       * target is address of the form host:port.
       * connected is the handler that is called when connection is succesfully established.
       * disconnected is a handler that is called when the connection is broken.
       * Return true on success.
       */
      bool Connect(const std::string &target, const ConnectionCB& connected, const ConnectionCB& disconnected);
  
      /**
       * Disconnect from Tor control port.
       */
      bool 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);
  
      /** Response handlers for async replies */
      boost::signals2::signal<void(TorControlConnection &,const TorControlReply &)> async_handler;
  private:
      /** Callback when ready for use */
      boost::function<void(TorControlConnection&)> connected;
      /** Callback when connection lost */
      boost::function<void(TorControlConnection&)> disconnected;
      /** Libevent event base */
      struct event_base *base;
      /** Connection to control socket */
      struct bufferevent *b_conn;
      /** 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);
  };
  
  TorControlConnection::TorControlConnection(struct event_base *base):
      base(base), b_conn(0)
  {
  }
  
  TorControlConnection::~TorControlConnection()
  {
      if (b_conn)
          bufferevent_free(b_conn);
  }
  
  void TorControlConnection::readcb(struct bufferevent *bev, void *ctx)
  {
      TorControlConnection *self = (TorControlConnection*)ctx;
      struct evbuffer *input = bufferevent_get_input(bev);
      size_t n_read_out = 0;
      char *line;
      assert(input);
      //  If there is not a whole line to read, evbuffer_readln returns NULL
      while((line = evbuffer_readln(input, &n_read_out, EVBUFFER_EOL_CRLF)) != NULL)
      {
          std::string s(line, n_read_out);
          free(line);
          if (s.size() < 4) // Short line
              continue;
          // <status>(-|+| )<data><CRLF>
          self->message.code = atoi(s.substr(0,3));
          self->message.lines.push_back(s.substr(4));
          char ch = s[3]; // '-','+' or ' '
          if (ch == ' ') {
              // Final line, dispatch reply and clean up
              if (self->message.code >= 600) {
                  // Dispatch async notifications to async handler
                  // Synchronous and asynchronous messages are never interleaved
                  self->async_handler(*self, self->message);
              } else {
                  if (!self->reply_handlers.empty()) {
                      // Invoke reply handler with message
                      self->reply_handlers.front()(*self, self->message);
                      self->reply_handlers.pop_front();
                  } else {
                      LogPrint("tor", "tor: Received unexpected sync reply %i\n", self->message.code);
                  }
              }
              self->message.Clear();
          }
      }
      //  Check for size of buffer - protect against memory exhaustion with very long lines
      //  Do this after evbuffer_readln to make sure all full lines have been
      //  removed from the buffer. Everything left is an incomplete line.
      if (evbuffer_get_length(input) > MAX_LINE_LENGTH) {
          LogPrintf("tor: Disconnecting because MAX_LINE_LENGTH exceeded\n");
          self->Disconnect();
      }
  }
  
  void TorControlConnection::eventcb(struct bufferevent *bev, short what, void *ctx)
  {
      TorControlConnection *self = (TorControlConnection*)ctx;
      if (what & BEV_EVENT_CONNECTED) {
          LogPrint("tor", "tor: Succesfully connected!\n");
          self->connected(*self);
      } else if (what & (BEV_EVENT_EOF|BEV_EVENT_ERROR)) {
          if (what & BEV_EVENT_ERROR)
              LogPrint("tor", "tor: Error connecting to Tor control socket\n");
          else
              LogPrint("tor", "tor: End of stream\n");
          self->Disconnect();
          self->disconnected(*self);
      }
  }
  
  bool TorControlConnection::Connect(const std::string &target, const ConnectionCB& connected, const ConnectionCB& disconnected)
  {
      if (b_conn)
          Disconnect();
      // Parse target address:port
      struct sockaddr_storage connect_to_addr;
      int connect_to_addrlen = sizeof(connect_to_addr);
      if (evutil_parse_sockaddr_port(target.c_str(),
          (struct sockaddr*)&connect_to_addr, &connect_to_addrlen)<0) {
          LogPrintf("tor: Error parsing socket address %s\n", target);
          return false;
      }
  
      // Create a new socket, set up callbacks and enable notification bits
      b_conn = bufferevent_socket_new(base, -1, BEV_OPT_CLOSE_ON_FREE);
      if (!b_conn)
          return false;
      bufferevent_setcb(b_conn, TorControlConnection::readcb, NULL, TorControlConnection::eventcb, this);
      bufferevent_enable(b_conn, EV_READ|EV_WRITE);
      this->connected = connected;
      this->disconnected = disconnected;
  
      // Finally, connect to target
      if (bufferevent_socket_connect(b_conn, (struct sockaddr*)&connect_to_addr, connect_to_addrlen) < 0) {
          LogPrintf("tor: Error connecting to address %s\n", target);
          return false;
      }
      return true;
  }
  
  bool TorControlConnection::Disconnect()
  {
      if (b_conn)
          bufferevent_free(b_conn);
      b_conn = 0;
      return true;
  }
  
  bool TorControlConnection::Command(const std::string &cmd, const ReplyHandlerCB& reply_handler)
  {
      if (!b_conn)
          return false;
      struct evbuffer *buf = bufferevent_get_output(b_conn);
      if (!buf)
          return false;
      evbuffer_add(buf, cmd.data(), cmd.size());
      evbuffer_add(buf, "\r\n", 2);
      reply_handlers.push_back(reply_handler);
      return true;
  }
  
  /****** General parsing utilities ********/
  
  /* Split reply line in the form 'AUTH METHODS=...' into a type
   * 'AUTH' and arguments 'METHODS=...'.
   */
  static std::pair<std::string,std::string> SplitTorReplyLine(const std::string &s)
  {
      size_t ptr=0;
      std::string type;
      while (ptr < s.size() && s[ptr] != ' ') {
          type.push_back(s[ptr]);
          ++ptr;
      }
      if (ptr < s.size())
          ++ptr; // skip ' '
      return make_pair(type, s.substr(ptr));
  }
  
  /** Parse reply arguments in the form 'METHODS=COOKIE,SAFECOOKIE COOKIEFILE=".../control_auth_cookie"'.
   */
  static std::map<std::string,std::string> ParseTorReplyMapping(const std::string &s)
  {
      std::map<std::string,std::string> mapping;
      size_t ptr=0;
      while (ptr < s.size()) {
          std::string key, value;
          while (ptr < s.size() && s[ptr] != '=') {
              key.push_back(s[ptr]);
              ++ptr;
          }
          if (ptr == s.size()) // unexpected end of line
              return std::map<std::string,std::string>();
          ++ptr; // skip '='
          if (ptr < s.size() && s[ptr] == '"') { // Quoted string
              ++ptr; // skip '='
              bool escape_next = false;
              while (ptr < s.size() && (!escape_next && s[ptr] != '"')) {
                  escape_next = (s[ptr] == '\\');
                  value.push_back(s[ptr]);
                  ++ptr;
              }
              if (ptr == s.size()) // unexpected end of line
                  return std::map<std::string,std::string>();
              ++ptr; // skip closing '"'
              /* TODO: unescape value - according to the spec this depends on the
               * context, some strings use C-LogPrintf style escape codes, some
               * don't. So may be better handled at the call site.
               */
          } else { // Unquoted value. Note that values can contain '=' at will, just no spaces
              while (ptr < s.size() && s[ptr] != ' ') {
                  value.push_back(s[ptr]);
                  ++ptr;
              }
          }
          if (ptr < s.size() && s[ptr] == ' ')
              ++ptr; // skip ' ' after key=value
          mapping[key] = value;
      }
      return mapping;
  }
  
  /** Read full contents of a file and return them in a std::string.
   * Returns a pair <status, string>.
   * If an error occured, status will be false, otherwise status will be true and the data will be returned in string.
   *
   * @param maxsize Puts a maximum size limit on the file that is read. If the file is larger than this, truncated data
   *         (with len > maxsize) will be returned.
   */
  static std::pair<bool,std::string> ReadBinaryFile(const std::string &filename, size_t maxsize=std::numeric_limits<size_t>::max())
  {
      FILE *f = fopen(filename.c_str(), "rb");
      if (f == NULL)
          return std::make_pair(false,"");
      std::string retval;
      char buffer[128];
      size_t n;
      while ((n=fread(buffer, 1, sizeof(buffer), f)) > 0) {
          retval.append(buffer, buffer+n);
          if (retval.size() > maxsize)
              break;
      }
      fclose(f);
      return std::make_pair(true,retval);
  }
  
  /** Write contents of std::string to a file.
   * @return true on success.
   */
  static bool WriteBinaryFile(const std::string &filename, const std::string &data)
  {
      FILE *f = fopen(filename.c_str(), "wb");
      if (f == NULL)
          return false;
      if (fwrite(data.data(), 1, data.size(), f) != data.size()) {
          fclose(f);
          return false;
      }
      fclose(f);
      return true;
  }
  
  /****** VCoin specific TorController implementation ********/
  
  /** Controller that connects to Tor control socket, authenticate, then create
   * and maintain a ephemeral hidden service.
   */
  class TorController
  {
  public:
      TorController(struct event_base* base, const std::string& target);
      ~TorController();
  
      /** Get name fo file to store private key in */
      std::string GetPrivateKeyFile();
  
      /** Reconnect, after getting disconnected */
      void Reconnect();
  private:
      struct event_base* base;
      std::string target;
      TorControlConnection conn;
      std::string private_key;
      std::string service_id;
      bool reconnect;
      struct event *reconnect_ev;
      float reconnect_timeout;
      CService service;
      /** Cooie for SAFECOOKIE auth */
      std::vector<uint8_t> cookie;
      /** ClientNonce for SAFECOOKIE auth */
      std::vector<uint8_t> clientNonce;
  
      /** 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 succesful 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);
  };
  
  TorController::TorController(struct event_base* base, const std::string& target):
      base(base),
      target(target), conn(base), reconnect(true), reconnect_ev(0),
      reconnect_timeout(RECONNECT_TIMEOUT_START)
  {
      // Start connection attempts immediately
      if (!conn.Connect(target, boost::bind(&TorController::connected_cb, this, _1),
           boost::bind(&TorController::disconnected_cb, this, _1) )) {
          LogPrintf("tor: Initiating connection to Tor control port %s failed\n", target);
      }
      // Read service private key if cached
      std::pair<bool,std::string> pkf = ReadBinaryFile(GetPrivateKeyFile());
      if (pkf.first) {
          LogPrint("tor", "tor: Reading cached private key from %s\n", GetPrivateKeyFile());
          private_key = pkf.second;
      }
  }
  
  TorController::~TorController()
  {
      if (reconnect_ev)
          event_del(reconnect_ev);
      if (service.IsValid()) {
          RemoveLocal(service);
      }
  }
  
  void TorController::add_onion_cb(TorControlConnection& conn, const TorControlReply& reply)
  {
      if (reply.code == 250) {
          LogPrint("tor", "tor: ADD_ONION succesful\n");
          BOOST_FOREACH(const std::string &s, reply.lines) {
              std::map<std::string,std::string> m = ParseTorReplyMapping(s);
              std::map<std::string,std::string>::iterator i;
              if ((i = m.find("ServiceID")) != m.end())
                  service_id = i->second;
              if ((i = m.find("PrivateKey")) != m.end())
                  private_key = i->second;
          }
  
          service = CService(service_id+".onion", GetListenPort(), false);
          LogPrintf("tor: Got service ID %s, advertizing service %s\n", service_id, service.ToString());
          if (WriteBinaryFile(GetPrivateKeyFile(), private_key)) {
              LogPrint("tor", "tor: Cached service private key to %s\n", GetPrivateKeyFile());
          } else {
              LogPrintf("tor: Error writing service private key to %s\n", GetPrivateKeyFile());
          }
          AddLocal(service, LOCAL_MANUAL);
          // ... onion requested - keep connection open
      } else if (reply.code == 510) { // 510 Unrecognized command
          LogPrintf("tor: Add onion failed with unrecognized command (You probably need to upgrade Tor)\n");
      } else {
          LogPrintf("tor: Add onion failed; error code %d\n", reply.code);
      }
  }
  
  void TorController::auth_cb(TorControlConnection& conn, const TorControlReply& reply)
  {
      if (reply.code == 250) {
          LogPrint("tor", "tor: Authentication succesful\n");
  
          // Now that we know Tor is running setup the proxy for onion addresses
          // if -onion isn't set to something else.
          if (GetArg("-onion", "") == "") {
              proxyType addrOnion = proxyType(CService("127.0.0.1", 9050), true);
              SetProxy(NET_TOR, addrOnion);
              SetReachable(NET_TOR);
          }
  
          // Finally - now create the service
          if (private_key.empty()) // No private key, generate one
              private_key = "NEW:BEST";
          // Request hidden service, redirect port.
          // Note that the 'virtual' port doesn't have to be the same as our internal port, but this is just a convenient
          // choice.  TODO; refactor the shutdown sequence some day.
          conn.Command(strprintf("ADD_ONION %s Port=%i,127.0.0.1:%i", private_key, GetListenPort(), GetListenPort()),
              boost::bind(&TorController::add_onion_cb, this, _1, _2));
      } else {
          LogPrintf("tor: Authentication failed\n");
      }
  }
  
  /** Compute Tor SAFECOOKIE response.
   *
   *    ServerHash is computed as:
   *      HMAC-SHA256("Tor safe cookie authentication server-to-controller hash",
   *                  CookieString | ClientNonce | ServerNonce)
   *    (with the HMAC key as its first argument)
   *
   *    After a controller sends a successful AUTHCHALLENGE command, the
   *    next command sent on the connection must be an AUTHENTICATE command,
   *    and the only authentication string which that AUTHENTICATE command
   *    will accept is:
   *
   *      HMAC-SHA256("Tor safe cookie authentication controller-to-server hash",
   *                  CookieString | ClientNonce | ServerNonce)
   *
   */
  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)
  {
      CHMAC_SHA256 computeHash((const uint8_t*)key.data(), key.size());
      std::vector<uint8_t> computedHash(CHMAC_SHA256::OUTPUT_SIZE, 0);
      computeHash.Write(begin_ptr(cookie), cookie.size());
      computeHash.Write(begin_ptr(clientNonce), clientNonce.size());
      computeHash.Write(begin_ptr(serverNonce), serverNonce.size());
      computeHash.Finalize(begin_ptr(computedHash));
      return computedHash;
  }
  
  void TorController::authchallenge_cb(TorControlConnection& conn, const TorControlReply& reply)
  {
      if (reply.code == 250) {
          LogPrint("tor", "tor: SAFECOOKIE authentication challenge succesful\n");
          std::pair<std::string,std::string> l = SplitTorReplyLine(reply.lines[0]);
          if (l.first == "AUTHCHALLENGE") {
              std::map<std::string,std::string> m = ParseTorReplyMapping(l.second);
              std::vector<uint8_t> serverHash = ParseHex(m["SERVERHASH"]);
              std::vector<uint8_t> serverNonce = ParseHex(m["SERVERNONCE"]);
              LogPrint("tor", "tor: AUTHCHALLENGE ServerHash %s ServerNonce %s\n", HexStr(serverHash), HexStr(serverNonce));
              if (serverNonce.size() != 32) {
                  LogPrintf("tor: ServerNonce is not 32 bytes, as required by spec\n");
                  return;
              }
  
              std::vector<uint8_t> computedServerHash = ComputeResponse(TOR_SAFE_SERVERKEY, cookie, clientNonce, serverNonce);
              if (computedServerHash != serverHash) {
                  LogPrintf("tor: ServerHash %s does not match expected ServerHash %s\n", HexStr(serverHash), HexStr(computedServerHash));
                  return;
              }
  
              std::vector<uint8_t> computedClientHash = ComputeResponse(TOR_SAFE_CLIENTKEY, cookie, clientNonce, serverNonce);
              conn.Command("AUTHENTICATE " + HexStr(computedClientHash), boost::bind(&TorController::auth_cb, this, _1, _2));
          } else {
              LogPrintf("tor: Invalid reply to AUTHCHALLENGE\n");
          }
      } else {
          LogPrintf("tor: SAFECOOKIE authentication challenge failed\n");
      }
  }
  
  void TorController::protocolinfo_cb(TorControlConnection& conn, const TorControlReply& reply)
  {
      if (reply.code == 250) {
          std::set<std::string> methods;
          std::string cookiefile;
          /*
           * 250-AUTH METHODS=COOKIE,SAFECOOKIE COOKIEFILE="/home/x/.tor/control_auth_cookie"
           * 250-AUTH METHODS=NULL
           * 250-AUTH METHODS=HASHEDPASSWORD
           */
          BOOST_FOREACH(const std::string &s, reply.lines) {
              std::pair<std::string,std::string> l = SplitTorReplyLine(s);
              if (l.first == "AUTH") {
                  std::map<std::string,std::string> m = ParseTorReplyMapping(l.second);
                  std::map<std::string,std::string>::iterator i;
                  if ((i = m.find("METHODS")) != m.end())
                      boost::split(methods, i->second, boost::is_any_of(","));
                  if ((i = m.find("COOKIEFILE")) != m.end())
                      cookiefile = i->second;
              } else if (l.first == "VERSION") {
                  std::map<std::string,std::string> m = ParseTorReplyMapping(l.second);
                  std::map<std::string,std::string>::iterator i;
                  if ((i = m.find("Tor")) != m.end()) {
                      LogPrint("tor", "tor: Connected to Tor version %s\n", i->second);
                  }
              }
          }
          BOOST_FOREACH(const std::string &s, methods) {
              LogPrint("tor", "tor: Supported authentication method: %s\n", s);
          }
          // Prefer NULL, otherwise SAFECOOKIE. If a password is provided, use HASHEDPASSWORD
          /* Authentication:
           *   cookie:   hex-encoded ~/.tor/control_auth_cookie
           *   password: "password"
           */
          std::string torpassword = GetArg("-torpassword", "");
          if (methods.count("NULL")) {
              LogPrint("tor", "tor: Using NULL authentication\n");
              conn.Command("AUTHENTICATE", boost::bind(&TorController::auth_cb, this, _1, _2));
          } else if (methods.count("SAFECOOKIE")) {
              // Cookie: hexdump -e '32/1 "%02x""\n"'  ~/.tor/control_auth_cookie
              LogPrint("tor", "tor: Using SAFECOOKIE authentication, reading cookie authentication from %s\n", cookiefile);
              std::pair<bool,std::string> status_cookie = ReadBinaryFile(cookiefile, TOR_COOKIE_SIZE);
              if (status_cookie.first && status_cookie.second.size() == TOR_COOKIE_SIZE) {
                  // conn.Command("AUTHENTICATE " + HexStr(status_cookie.second), boost::bind(&TorController::auth_cb, this, _1, _2));
                  cookie = std::vector<uint8_t>(status_cookie.second.begin(), status_cookie.second.end());
                  clientNonce = std::vector<uint8_t>(TOR_NONCE_SIZE, 0);
                  GetRandBytes(&clientNonce[0], TOR_NONCE_SIZE);
                  conn.Command("AUTHCHALLENGE SAFECOOKIE " + HexStr(clientNonce), boost::bind(&TorController::authchallenge_cb, this, _1, _2));
              } else {
                  if (status_cookie.first) {
                      LogPrintf("tor: Authentication cookie %s is not exactly %i bytes, as is required by the spec\n", cookiefile, TOR_COOKIE_SIZE);
                  } else {
                      LogPrintf("tor: Authentication cookie %s could not be opened (check permissions)\n", cookiefile);
                  }
              }
          } else if (methods.count("HASHEDPASSWORD")) {
              if (!torpassword.empty()) {
                  LogPrint("tor", "tor: Using HASHEDPASSWORD authentication\n");
                  boost::replace_all(torpassword, "\"", "\\\"");
                  conn.Command("AUTHENTICATE \"" + torpassword + "\"", boost::bind(&TorController::auth_cb, this, _1, _2));
              } else {
                  LogPrintf("tor: Password authentication required, but no password provided with -torpassword\n");
              }
          } else {
              LogPrintf("tor: No supported authentication method\n");
          }
      } else {
          LogPrintf("tor: Requesting protocol info failed\n");
      }
  }
  
  void TorController::connected_cb(TorControlConnection& conn)
  {
      reconnect_timeout = RECONNECT_TIMEOUT_START;
      // First send a PROTOCOLINFO command to figure out what authentication is expected
      if (!conn.Command("PROTOCOLINFO 1", boost::bind(&TorController::protocolinfo_cb, this, _1, _2)))
          LogPrintf("tor: Error sending initial protocolinfo command\n");
  }
  
  void TorController::disconnected_cb(TorControlConnection& conn)
  {
      // Stop advertizing service when disconnected
      if (service.IsValid())
          RemoveLocal(service);
      service = CService();
      if (!reconnect)
          return;
  
      LogPrint("tor", "tor: Not connected to Tor control port %s, trying to reconnect\n", target);
  
      // Single-shot timer for reconnect. Use exponential backoff.
      struct timeval time = MillisToTimeval(int64_t(reconnect_timeout * 1000.0));
      reconnect_ev = event_new(base, -1, 0, reconnect_cb, this);
      event_add(reconnect_ev, &time);
      reconnect_timeout *= RECONNECT_TIMEOUT_EXP;
  }
  
  void TorController::Reconnect()
  {
      /* Try to reconnect and reestablish if we get booted - for example, Tor
       * may be restarting.
       */
      if (!conn.Connect(target, boost::bind(&TorController::connected_cb, this, _1),
           boost::bind(&TorController::disconnected_cb, this, _1) )) {
          LogPrintf("tor: Re-initiating connection to Tor control port %s failed\n", target);
      }
  }
  
  std::string TorController::GetPrivateKeyFile()
  {
      return (GetDataDir() / "onion_private_key").string();
  }
  
  void TorController::reconnect_cb(evutil_socket_t fd, short what, void *arg)
  {
      TorController *self = (TorController*)arg;
      self->Reconnect();
  }
  
  /****** Thread ********/
  struct event_base *base;
  boost::thread torControlThread;
  
  static void TorControlThread()
  {
      TorController ctrl(base, GetArg("-torcontrol", DEFAULT_TOR_CONTROL));
  
      event_base_dispatch(base);
  }
  
  void StartTorControl(boost::thread_group& threadGroup, CScheduler& scheduler)
  {
      assert(!base);
  #ifdef WIN32
      evthread_use_windows_threads();
  #else
      evthread_use_pthreads();
  #endif
      base = event_base_new();
      if (!base) {
          LogPrintf("tor: Unable to create event_base\n");
          return;
      }
  
      torControlThread = boost::thread(boost::bind(&TraceThread<void (*)()>, "torcontrol", &TorControlThread));
  }
  
  void InterruptTorControl()
  {
      if (base) {
          LogPrintf("tor: Thread interrupt\n");
          event_base_loopbreak(base);
      }
  }
  
  void StopTorControl()
  {
      if (base) {
          torControlThread.join();
          event_base_free(base);
          base = 0;
      }
  }
  
  