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         dout("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                 q->DoRead(1000);        // timeout in milliseconds
 104         }
 105         return 0;
 106 }
 107
 108
 109 ///////////////////////////////////////////////////////////////////////////////
 110 // public API
 111
 112 // These functions connect the router to an external Usb::Device
 113 // object.  Normally this is handled automatically by the
 114 // Controller class, but are public here in case they are needed.
 115 void SocketRoutingQueue::SetUsbDevice(Usb::Device *dev, int writeEp, int readEp)
 116 {
 117         scoped_lock lock(m_mutex);
 118         m_dev = dev;
 119         m_writeEp = writeEp;
 120         m_readEp = readEp;
 121 }
 122
 123 void SocketRoutingQueue::ClearUsbDevice()
 124 {
 125         scoped_lock lock(m_mutex);
 126         m_dev = 0;
 127         lock.unlock();
 128
 129         // wait for the DoRead cycle to finish, so the external
 130         // Usb::Device object doesn't close before we're done with it
 131         scoped_lock wait(m_readwaitMutex);
 132         pthread_cond_wait(&m_readwaitCond, &m_readwaitMutex);
 133 }
 134
 135 bool SocketRoutingQueue::UsbDeviceReady()
 136 {
 137         scoped_lock lock(m_mutex);
 138         return m_dev != 0;
 139 }
 140
 141 //
 142 // AllocateBuffers
 143 //
 144 /// This class starts out with no buffers, and will grow one buffer
 145 /// at a time if needed.  Call this to allocate count buffers
 146 /// all at once and place them on the free queue.  After calling
 147 /// this function, at least count buffers will exist in the free
 148 /// queue.  If there are already count buffers, none will be added.
 149 ///
 150 void SocketRoutingQueue::AllocateBuffers(int count)
 151 {
 152         int todo = count - m_free.size();
 153
 154         for( int i = 0; i < todo; i++ ) {
 155                 // m_free handles its own locking
 156                 m_free.push( new Data );
 157         }
 158 }
 159
 160 //
 161 // DefaultRead (both variations)
 162 //
 163 /// Returns the data for the next unregistered socket.
 164 /// Blocks until timeout or data is available.
 165 /// Returns false (or null pointer) on timeout and no data.
 166 /// With the return version of the function, there is no
 167 /// copying performed.
 168 ///
 169 /// This version performs a copy.
 170 ///
 171 bool SocketRoutingQueue::DefaultRead(Data &receive, int timeout)
 172 {
 173         DataHandle buf = DefaultRead(timeout);
 174         if( !buf.get() )
 175                 return false;
 176
 177         // copy to desired buffer
 178         receive = *buf.get();
 179         return true;
 180 }
 181
 182 ///
 183 /// This version does not perform a copy.
 184 ///
 185 DataHandle SocketRoutingQueue::DefaultRead(int timeout)
 186 {
 187         // m_default handles its own locking
 188         Data *buf = m_default.wait_pop(timeout);
 189         return DataHandle(*this, buf);
 190 }
 191
 192 //
 193 // RegisterInterest
 194 //
 195 /// Register an interest in data from a certain socket.  To read
 196 /// from that socket, use the SocketRead() function from then on.
 197 ///
 198 /// Any non-registered socket goes in the default queue
 199 /// and must be read by DefaultRead()
 200 ///
 201 /// If not null, handler is called when new data is read.  It will
 202 /// be called in the same thread instance that DoRead() is called from.
 203 /// Handler is passed the DataQueue Data pointer, and so no
 204 /// copying is done.  Once the handler returns, the data is
 205 /// considered processed and not added to the interested queue,
 206 /// but instead returned to m_free.
 207 ///
 208 /// Throws std::logic_error if already registered.
 209 ///
 210 void SocketRoutingQueue::RegisterInterest(SocketId socket,
 211                                           SocketDataHandlerPtr handler)
 212 {
 213         // modifying our own std::map, need a lock
 214         scoped_lock lock(m_mutex);
 215
 216         SocketQueueMap::iterator qi = m_socketQueues.find(socket);
 217         if( qi != m_socketQueues.end() )
 218                 throw std::logic_error("RegisterInterest requesting a previously registered socket.");
 219
 220         m_socketQueues[socket] = QueueEntryPtr( new QueueEntry(handler) );
 221         m_interest = true;
 222 }
 223
 224 //
 225 // UnregisterInterest
 226 //
 227 /// Unregisters interest in data from the given socket, and discards
 228 /// any existing data in its interest queue.  Any new incoming data
 229 /// for this socket will be placed in the default queue.
 230 ///
 231 void SocketRoutingQueue::UnregisterInterest(SocketId socket)
 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                 return; // nothing registered, done
 239
 240         // salvage all our data buffers
 241         m_free.append_from( qi->second->m_queue );
 242
 243         // remove the QueueEntryPtr from the map
 244         m_socketQueues.erase( qi );
 245
 246         // check the interest flag
 247         m_interest = m_socketQueues.size() > 0;
 248 }
 249
 250 //
 251 // SocketRead
 252 //
 253 /// Reads data from the interested socket cache.  Can only read
 254 /// from sockets that have been previously registered.
 255 ///
 256 /// Blocks until timeout or data is available.
 257 ///
 258 /// Returns false (or null pointer) on timeout and no data.
 259 /// With the return version of the function, there is no
 260 /// copying performed.
 261 ///
 262 /// Throws std::logic_error if a socket was requested that was
 263 /// not previously registered.
 264 ///
 265 /// Copying is performed with this function.
 266 ///
 267 bool SocketRoutingQueue::SocketRead(SocketId socket, Data &receive, int timeout)
 268 {
 269         DataHandle buf = SocketRead(socket, timeout);
 270         if( !buf.get() )
 271                 return false;
 272
 273         // copy to desired buffer
 274         receive = *buf.get();
 275         return true;
 276 }
 277
 278 ///
 279 /// Copying is not performed with this function.
 280 ///
 281 /// Throws std::logic_error if a socket was requested that was
 282 /// not previously registered.
 283 ///
 284 DataHandle SocketRoutingQueue::SocketRead(SocketId socket, int timeout)
 285 {
 286         QueueEntryPtr qep;
 287         DataQueue *dq = 0;
 288
 289         // accessing our own std::map, need a lock
 290         {
 291                 scoped_lock lock(m_mutex);
 292                 SocketQueueMap::iterator qi = m_socketQueues.find(socket);
 293                 if( qi == m_socketQueues.end() )
 294                         throw std::logic_error("SocketRead requested data from unregistered socket.");
 295
 296                 // got our queue, save the whole QueueEntryPtr (shared_ptr),
 297                 // and unlock, since we will be waiting on the DataQueue,
 298                 // not the socketQueues map
 299                 //
 300                 // This is safe, since even if UnregisterInterest is called,
 301                 // our pointer won't be deleted until our shared_ptr
 302                 // (QueueEntryPtr) goes out of scope.
 303                 //
 304                 // The remaining problem is that wait_pop() might wait
 305                 // forever if there is no timeout... c'est la vie.
 306                 // Should'a used a timeout. :-)
 307                 qep = qi->second;
 308                 dq = &qep->m_queue;
 309         }
 310
 311         // get data from DataQueue
 312         Data *buf = dq->wait_pop(timeout);
 313
 314         // specifically delete our copy of shared pointer, in a locked
 315         // environment
 316         {
 317                 scoped_lock lock(m_mutex);
 318                 qep.reset();
 319         }
 320
 321         return DataHandle(*this, buf);
 322 }
 323
 324 // Returns true if data is available for that socket.
 325 bool SocketRoutingQueue::IsAvailable(SocketId socket) const
 326 {
 327         scoped_lock lock(m_mutex);
 328         SocketQueueMap::const_iterator qi = m_socketQueues.find(socket);
 329         if( qi == m_socketQueues.end() )
 330                 return false;
 331         return qi->second->m_queue.size() > 0;
 332 }
 333
 334 //
 335 // DoRead
 336 //
 337 /// Called by the application's "read thread" to read the next usb
 338 /// packet and route it to the correct queue.  Returns after every
 339 /// read, even if a handler is associated with a queue.
 340 /// Note: this function is safe to call before SetUsbDevice() is
 341 /// called... it just doesn't do anything if there is no usb
 342 /// device to work with.
 343 ///
 344 /// Timeout is in milliseconds.
 345 void SocketRoutingQueue::DoRead(int timeout)
 346 {
 347         class ReadWaitSignal
 348         {
 349                 pthread_mutex_t &m_Mutex;
 350                 pthread_cond_t &m_Cond;
 351         public:
 352                 ReadWaitSignal(pthread_mutex_t &mut, pthread_cond_t &cond)
 353                         : m_Mutex(mut), m_Cond(cond)
 354                         {}
 355                 ~ReadWaitSignal()
 356                 {
 357                         scoped_lock wait(m_Mutex);
 358                         pthread_cond_signal(&m_Cond);
 359                 }
 360         } readwait(m_readwaitMutex, m_readwaitCond);
 361
 362         Usb::Device * volatile dev = 0;
 363         int readEp;
 364         DataHandle buf(*this, 0);
 365
 366         // if we are not connected to a USB device yet, just wait
 367         {
 368                 scoped_lock lock(m_mutex);
 369
 370                 if( !m_dev || m_seen_usb_error ) {
 371                         lock.unlock();  // unlock early, since we're sleeping
 372                         // sleep only a short time, since things could be
 373                         // in the process of setup or teardown
 374                         usleep(125000);
 375                         return;
 376                 }
 377
 378                 dev = m_dev;
 379                 readEp = m_readEp;
 380
 381                 // fetch a free buffer
 382                 Data *raw = m_free.pop();
 383                 if( !raw )
 384                         buf = DataHandle(*this, new Data);
 385                 else
 386                         buf = DataHandle(*this, raw);
 387         }
 388
 389         // take a chance and do the read unlocked, as this has the potential
 390         // for blocking for a while
 391         try {
 392
 393                 Data &data = *buf.get();
 394
 395                 if( !dev->BulkRead(readEp, data, timeout) )
 396                         return; // no data, done!
 397
 398                 MAKE_PACKET(pack, data);
 399
 400                 // make sure the size is right
 401                 if( data.GetSize() < sizeof(pack->socket) )
 402                         return; // bad size, just skip
 403
 404                 // extract the socket from the packet
 405                 uint16_t socket = btohs(pack->socket);
 406
 407                 // we have data, now lock up again to place it
 408                 // in the right queue
 409                 scoped_lock lock(m_mutex);
 410
 411                 // search for registration of socket
 412                 if( m_interest ) {
 413                         SocketQueueMap::iterator qi = m_socketQueues.find(socket);
 414                         if( qi != m_socketQueues.end() ) {
 415                                 SocketDataHandlerPtr &sdh = qi->second->m_handler;
 416
 417                                 // is there a handler?
 418                                 if( sdh ) {
 419                                         // unlock & let the handler process it
 420                                         lock.unlock();
 421                                         sdh->DataReceived(*buf.get());
 422                                         return;
 423                                 }
 424                                 else {
 425                                         qi->second->m_queue.push(buf.release());
 426                                         return;
 427                                 }
 428                         }
 429
 430                         // fall through
 431                 }
 432
 433                 // safe to unlock now, we are done with the map
 434                 lock.unlock();
 435
 436                 // if we get here, send to default queue
 437                 m_default.push(buf.release());
 438         }
 439         catch( Usb::Timeout & ) {
 440                 // this is expected... just ignore
 441         }
 442         catch( Usb::Error &ue ) {
 443                 // this is unexpected, but we're in a thread here...
 444                 // Need to iterate through all the registered handlers
 445                 // calling their error callback.
 446                 // Can't be locked when calling the callback, so need
 447                 // to make a list of them first.
 448                 scoped_lock lock(m_mutex);
 449                 std::vector<SocketDataHandlerPtr> handlers;
 450                 SocketQueueMap::iterator qi = m_socketQueues.begin();
 451                 while( qi != m_socketQueues.end() ) {
 452                         SocketDataHandlerPtr &sdh = qi->second->m_handler;
 453                         // is there a handler?
 454                         if( sdh ) {
 455                                 handlers.push_back(sdh);
 456                         }
 457                         ++qi;
 458                 }
 459                 lock.unlock();
 460                 std::vector<SocketDataHandlerPtr>::iterator hi = handlers.begin();
 461                 while( hi != handlers.end() ) {
 462                         (*hi)->Error(ue);
 463                         ++hi;
 464                 }
 465                 m_seen_usb_error = true;
 466         }
 467 }
 468
 469 void SocketRoutingQueue::SpinoffSimpleReadThread()
 470 {
 471         // signal that it's ok to run inside the thread
 472         if( m_continue_reading )
 473                 return; // already running
 474         m_continue_reading = true;
 475
 476         // Start USB read thread, to handle all routing
 477         int ret = pthread_create(&m_usb_read_thread, NULL, &SimpleReadThread, this);
 478         if( ret ) {
 479                 m_continue_reading = false;
 480                 throw Barry::ErrnoError("SocketRoutingQueue: Error creating USB read thread.", ret);
 481         }
 482 }
 483
 484 } // namespace Barry
 485