src/router.cc

   1 ///
   2 /// \file       router.cc
   3 ///             Support classes for the pluggable socket routing system.
   4 ///
   5
   6 /*
   7     Copyright (C) 2008-2010, Net Direct Inc. (http://www.netdirect.ca/)
   8
   9     This program is free software; you can redistribute it and/or modify
  10     it under the terms of the GNU General Public License as published by
  11     the Free Software Foundation; either version 2 of the License, or
  12     (at your option) any later version.
  13
  14     This program is distributed in the hope that it will be useful,
  15     but WITHOUT ANY WARRANTY; without even the implied warranty of
  16     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
  17
  18     See the GNU General Public License in the COPYING file at the
  19     root directory of this project for more details.
  20 */
  21
  22 #include "router.h"
  23 #include "scoped_lock.h"
  24 #include "data.h"
  25 #include "protostructs.h"
  26 #include "usbwrap.h"
  27 #include "endian.h"
  28 #include "debug.h"
  29 #include <unistd.h>
  30
  31 namespace Barry {
  32
  33 ///////////////////////////////////////////////////////////////////////////////
  34 // SocketDataHandler default methods
  35
  36 void SocketRoutingQueue::SocketDataHandler::Error(Barry::Error &error)
  37 {
  38         // Just log the error
  39         eout("SocketDataHandler: Error: " << error.what());
  40         (void) error;
  41 }
  42
  43 SocketRoutingQueue::SocketDataHandler::~SocketDataHandler()
  44 {
  45         // Nothing to destroy
  46 }
  47
  48 ///////////////////////////////////////////////////////////////////////////////
  49 // SocketRoutingQueue constructors
  50
  51 SocketRoutingQueue::SocketRoutingQueue(int prealloc_buffer_count)
  52         : m_dev(0)
  53         , m_writeEp(0)
  54         , m_readEp(0)
  55         , m_interest(false)
  56         , m_seen_usb_error(false)
  57         , m_continue_reading(false)
  58 {
  59         pthread_mutex_init(&m_mutex, NULL);
  60
  61         pthread_mutex_init(&m_readwaitMutex, NULL);
  62         pthread_cond_init(&m_readwaitCond, NULL);
  63
  64         AllocateBuffers(prealloc_buffer_count);
  65 }
  66
  67 SocketRoutingQueue::~SocketRoutingQueue()
  68 {
  69         // thread running?
  70         if( m_continue_reading ) {
  71                 m_continue_reading = false;
  72                 pthread_join(m_usb_read_thread, NULL);
  73         }
  74 }
  75
  76 ///////////////////////////////////////////////////////////////////////////////
  77 // protected members
  78
  79 //
  80 // ReturnBuffer
  81 //
  82 /// Provides a method of returning a buffer to the free queue
  83 /// after processing.  The DataHandle class calls this automatically
  84 /// from its destructor.
  85 void SocketRoutingQueue::ReturnBuffer(Data *buf)
  86 {
  87         // don't need to lock here, since m_free handles its own locking
  88         m_free.push(buf);
  89 }
  90
  91 //
  92 // SimpleReadThread()
  93 //
  94 /// Convenience thread to handle USB read activity.
  95 ///
  96 void *SocketRoutingQueue::SimpleReadThread(void *userptr)
  97 {
  98         SocketRoutingQueue *q = (SocketRoutingQueue *)userptr;
  99
 100         // read from USB and write to stdout until finished
 101         q->m_seen_usb_error = false;
 102         while( q->m_continue_reading ) {
 103                 try {
 104                         q->DoRead(1000);        // timeout in milliseconds
 105                 }
 106                 catch (std::runtime_error const &e) {
 107                         eout("SimpleReadThread received uncaught exception: " <<  typeid(e).name() << " what: " << e.what());
 108                 }
 109                 catch (...) {
 110                         eout("SimpleReadThread recevied uncaught exception of unknown type");
 111                 }
 112         }
 113         return 0;
 114 }
 115
 116
 117 ///////////////////////////////////////////////////////////////////////////////
 118 // public API
 119
 120 // These functions connect the router to an external Usb::Device
 121 // object.  Normally this is handled automatically by the
 122 // Controller class, but are public here in case they are needed.
 123 void SocketRoutingQueue::SetUsbDevice(Usb::Device *dev, int writeEp, int readEp,
 124                                         SocketDataHandlerPtr callback)
 125 {
 126         scoped_lock lock(m_mutex);
 127         m_dev = dev;
 128         m_usb_error_dev_callback = callback;
 129         m_writeEp = writeEp;
 130         m_readEp = readEp;
 131 }
 132
 133 void SocketRoutingQueue::ClearUsbDevice()
 134 {
 135         scoped_lock lock(m_mutex);
 136         m_dev = 0;
 137         m_usb_error_dev_callback.reset();
 138         lock.unlock();
 139
 140         // wait for the DoRead cycle to finish, so the external
 141         // Usb::Device object doesn't close before we're done with it
 142         scoped_lock wait(m_readwaitMutex);
 143         pthread_cond_wait(&m_readwaitCond, &m_readwaitMutex);
 144 }
 145
 146 bool SocketRoutingQueue::UsbDeviceReady()
 147 {
 148         scoped_lock lock(m_mutex);
 149         return m_dev != 0 && !m_seen_usb_error;
 150 }
 151
 152 //
 153 // AllocateBuffers
 154 //
 155 /// This class starts out with no buffers, and will grow one buffer
 156 /// at a time if needed.  Call this to allocate count buffers
 157 /// all at once and place them on the free queue.  After calling
 158 /// this function, at least count buffers will exist in the free
 159 /// queue.  If there are already count buffers, none will be added.
 160 ///
 161 void SocketRoutingQueue::AllocateBuffers(int count)
 162 {
 163         int todo = count - m_free.size();
 164
 165         for( int i = 0; i < todo; i++ ) {
 166                 // m_free handles its own locking
 167                 m_free.push( new Data );
 168         }
 169 }
 170
 171 //
 172 // DefaultRead (both variations)
 173 //
 174 /// Returns the data for the next unregistered socket.
 175 /// Blocks until timeout or data is available.
 176 /// Returns false (or null pointer) on timeout and no data.
 177 /// With the return version of the function, there is no
 178 /// copying performed.
 179 ///
 180 /// This version performs a copy.
 181 ///
 182 bool SocketRoutingQueue::DefaultRead(Data &receive, int timeout)
 183 {
 184         DataHandle buf = DefaultRead(timeout);
 185         if( !buf.get() )
 186                 return false;
 187
 188         // copy to desired buffer
 189         receive = *buf.get();
 190         return true;
 191 }
 192
 193 ///
 194 /// This version does not perform a copy.
 195 ///
 196 DataHandle SocketRoutingQueue::DefaultRead(int timeout)
 197 {
 198         if( m_seen_usb_error && timeout == -1 ) {
 199                 // If an error has been seen and not cleared then no
 200                 // more data will be read into the queue by
 201                 // DoRead(). Forcing the timeout to zero allows any
 202                 // data already in the queue to be read, but prevents
 203                 // waiting for data which will never arrive.
 204                 timeout = 0;
 205         }
 206
 207         // m_default handles its own locking
 208         Data *buf = m_default.wait_pop(timeout);
 209         return DataHandle(*this, buf);
 210 }
 211
 212 //
 213 // RegisterInterest
 214 //
 215 /// Register an interest in data from a certain socket.  To read
 216 /// from that socket, use the SocketRead() function from then on.
 217 ///
 218 /// Any non-registered socket goes in the default queue
 219 /// and must be read by DefaultRead()
 220 ///
 221 /// If not null, handler is called when new data is read.  It will
 222 /// be called in the same thread instance that DoRead() is called from.
 223 /// Handler is passed the DataQueue Data pointer, and so no
 224 /// copying is done.  Once the handler returns, the data is
 225 /// considered processed and not added to the interested queue,
 226 /// but instead returned to m_free.
 227 ///
 228 /// Throws std::logic_error if already registered.
 229 ///
 230 void SocketRoutingQueue::RegisterInterest(SocketId socket,
 231                                           SocketDataHandlerPtr handler)
 232 {
 233         // modifying our own std::map, need a lock
 234         scoped_lock lock(m_mutex);
 235
 236         SocketQueueMap::iterator qi = m_socketQueues.find(socket);
 237         if( qi != m_socketQueues.end() )
 238                 throw std::logic_error("RegisterInterest requesting a previously registered socket.");
 239
 240         m_socketQueues[socket] = QueueEntryPtr( new QueueEntry(handler) );
 241         m_interest = true;
 242 }
 243
 244 //
 245 // UnregisterInterest
 246 //
 247 /// Unregisters interest in data from the given socket, and discards
 248 /// any existing data in its interest queue.  Any new incoming data
 249 /// for this socket will be placed in the default queue.
 250 ///
 251 void SocketRoutingQueue::UnregisterInterest(SocketId socket)
 252 {
 253         // modifying our own std::map, need a lock
 254         scoped_lock lock(m_mutex);
 255
 256         SocketQueueMap::iterator qi = m_socketQueues.find(socket);
 257         if( qi == m_socketQueues.end() )
 258                 return; // nothing registered, done
 259
 260         // salvage all our data buffers
 261         m_free.append_from( qi->second->m_queue );
 262
 263         // remove the QueueEntryPtr from the map
 264         m_socketQueues.erase( qi );
 265
 266         // check the interest flag
 267         m_interest = m_socketQueues.size() > 0;
 268 }
 269
 270 //
 271 // SocketRead
 272 //
 273 /// Reads data from the interested socket cache.  Can only read
 274 /// from sockets that have been previously registered.
 275 ///
 276 /// Blocks until timeout or data is available.
 277 ///
 278 /// Returns false (or null pointer) on timeout and no data.
 279 /// With the return version of the function, there is no
 280 /// copying performed.
 281 ///
 282 /// Throws std::logic_error if a socket was requested that was
 283 /// not previously registered.
 284 ///
 285 /// Copying is performed with this function.
 286 ///
 287 bool SocketRoutingQueue::SocketRead(SocketId socket, Data &receive, int timeout)
 288 {
 289         DataHandle buf = SocketRead(socket, timeout);
 290         if( !buf.get() )
 291                 return false;
 292
 293         // copy to desired buffer
 294         receive = *buf.get();
 295         return true;
 296 }
 297
 298 ///
 299 /// Copying is not performed with this function.
 300 ///
 301 /// Throws std::logic_error if a socket was requested that was
 302 /// not previously registered.
 303 ///
 304 DataHandle SocketRoutingQueue::SocketRead(SocketId socket, int timeout)
 305 {
 306         QueueEntryPtr qep;
 307         DataQueue *dq = 0;
 308
 309         // accessing our own std::map, need a lock
 310         {
 311                 scoped_lock lock(m_mutex);
 312                 SocketQueueMap::iterator qi = m_socketQueues.find(socket);
 313                 if( qi == m_socketQueues.end() )
 314                         throw std::logic_error("SocketRead requested data from unregistered socket.");
 315
 316                 // got our queue, save the whole QueueEntryPtr (shared_ptr),
 317                 // and unlock, since we will be waiting on the DataQueue,
 318                 // not the socketQueues map
 319                 //
 320                 // This is safe, since even if UnregisterInterest is called,
 321                 // our pointer won't be deleted until our shared_ptr
 322                 // (QueueEntryPtr) goes out of scope.
 323                 //
 324                 // The remaining problem is that wait_pop() might wait
 325                 // forever if there is no timeout... c'est la vie.
 326                 // Should'a used a timeout. :-)
 327                 qep = qi->second;
 328                 dq = &qep->m_queue;
 329         }
 330
 331         // get data from DataQueue
 332         Data *buf = dq->wait_pop(timeout);
 333
 334         // specifically delete our copy of shared pointer, in a locked
 335         // environment
 336         {
 337                 scoped_lock lock(m_mutex);
 338                 qep.reset();
 339         }
 340
 341         return DataHandle(*this, buf);
 342 }
 343
 344 // Returns true if data is available for that socket.
 345 bool SocketRoutingQueue::IsAvailable(SocketId socket) const
 346 {
 347         scoped_lock lock(m_mutex);
 348         SocketQueueMap::const_iterator qi = m_socketQueues.find(socket);
 349         if( qi == m_socketQueues.end() )
 350                 return false;
 351         return qi->second->m_queue.size() > 0;
 352 }
 353
 354 //
 355 // DoRead
 356 //
 357 /// Called by the application's "read thread" to read the next usb
 358 /// packet and route it to the correct queue.  Returns after every
 359 /// read, even if a handler is associated with a queue.
 360 /// Note: this function is safe to call before SetUsbDevice() is
 361 /// called... it just doesn't do anything if there is no usb
 362 /// device to work with.
 363 ///
 364 /// Timeout is in milliseconds.
 365 void SocketRoutingQueue::DoRead(int timeout)
 366 {
 367         class ReadWaitSignal
 368         {
 369                 pthread_mutex_t &m_Mutex;
 370                 pthread_cond_t &m_Cond;
 371         public:
 372                 ReadWaitSignal(pthread_mutex_t &mut, pthread_cond_t &cond)
 373                         : m_Mutex(mut), m_Cond(cond)
 374                         {}
 375                 ~ReadWaitSignal()
 376                 {
 377                         scoped_lock wait(m_Mutex);
 378                         pthread_cond_signal(&m_Cond);
 379                 }
 380         } readwait(m_readwaitMutex, m_readwaitCond);
 381
 382         Usb::Device * volatile dev = 0;
 383         int readEp;
 384         DataHandle buf(*this, 0);
 385
 386         // if we are not connected to a USB device yet, just wait
 387         {
 388                 scoped_lock lock(m_mutex);
 389
 390                 if( !m_dev || m_seen_usb_error ) {
 391                         lock.unlock();  // unlock early, since we're sleeping
 392                         // sleep only a short time, since things could be
 393                         // in the process of setup or teardown
 394                         usleep(125000);
 395                         return;
 396                 }
 397
 398                 dev = m_dev;
 399                 readEp = m_readEp;
 400
 401                 // fetch a free buffer
 402                 Data *raw = m_free.pop();
 403                 if( !raw )
 404                         buf = DataHandle(*this, new Data);
 405                 else
 406                         buf = DataHandle(*this, raw);
 407         }
 408
 409         // take a chance and do the read unlocked, as this has the potential
 410         // for blocking for a while
 411         try {
 412
 413                 Data &data = *buf.get();
 414
 415                 if( !dev->BulkRead(readEp, data, timeout) )
 416                         return; // no data, done!
 417
 418                 MAKE_PACKET(pack, data);
 419
 420                 // make sure the size is right
 421                 if( data.GetSize() < SB_PACKET_SOCKET_SIZE )
 422                         return; // bad size, just skip
 423
 424                 // extract the socket from the packet
 425                 uint16_t socket = btohs(pack->socket);
 426
 427                 // we have data, now lock up again to place it
 428                 // in the right queue
 429                 scoped_lock lock(m_mutex);
 430
 431                 // search for registration of socket
 432                 if( m_interest ) {
 433                         SocketQueueMap::iterator qi = m_socketQueues.find(socket);
 434                         if( qi != m_socketQueues.end() ) {
 435                                 SocketDataHandlerPtr &sdh = qi->second->m_handler;
 436
 437                                 // is there a handler?
 438                                 if( sdh ) {
 439                                         // unlock & let the handler process it
 440                                         lock.unlock();
 441                                         sdh->DataReceived(*buf.get());
 442                                         return;
 443                                 }
 444                                 else {
 445                                         qi->second->m_queue.push(buf.release());
 446                                         return;
 447                                 }
 448                         }
 449
 450                         // fall through
 451                 }
 452
 453                 // safe to unlock now, we are done with the map
 454                 lock.unlock();
 455
 456                 // if we get here, send to default queue
 457                 m_default.push(buf.release());
 458         }
 459         catch( Usb::Timeout & ) {
 460                 // this is expected... just ignore
 461         }
 462         catch( Usb::Error &ue ) {
 463                 // set the flag first, in case any of the handlers
 464                 // are able to recover from this error
 465                 m_seen_usb_error = true;
 466
 467                 // this is unexpected, but we're in a thread here...
 468                 // Need to iterate through all the registered handlers
 469                 // calling their error callback.
 470                 // Can't be locked when calling the callback, so need
 471                 // to make a list of them first.
 472                 scoped_lock lock(m_mutex);
 473                 std::vector<SocketDataHandlerPtr> handlers;
 474                 SocketQueueMap::iterator qi = m_socketQueues.begin();
 475                 while( qi != m_socketQueues.end() ) {
 476                         SocketDataHandlerPtr &sdh = qi->second->m_handler;
 477                         // is there a handler?
 478                         if( sdh ) {
 479                                 handlers.push_back(sdh);
 480                         }
 481                         ++qi;
 482                 }
 483
 484                 SocketDataHandlerPtr usb_error_handler = m_usb_error_dev_callback;
 485
 486                 lock.unlock();
 487                 std::vector<SocketDataHandlerPtr>::iterator hi = handlers.begin();
 488                 while( hi != handlers.end() ) {
 489                         (*hi)->Error(ue);
 490                         ++hi;
 491                 }
 492
 493                 // and finally, call the specific error callback if available
 494                 if( usb_error_handler.get() ) {
 495                         usb_error_handler->Error(ue);
 496                 }
 497         }
 498 }
 499
 500 void SocketRoutingQueue::SpinoffSimpleReadThread()
 501 {
 502         // signal that it's ok to run inside the thread
 503         if( m_continue_reading )
 504                 return; // already running
 505         m_continue_reading = true;
 506
 507         // Start USB read thread, to handle all routing
 508         int ret = pthread_create(&m_usb_read_thread, NULL, &SimpleReadThread, this);
 509         if( ret ) {
 510                 m_continue_reading = false;
 511                 throw Barry::ErrnoError("SocketRoutingQueue: Error creating USB read thread.", ret);
 512         }
 513 }
 514
 515 } // namespace Barry
 516