boost/asio/ssl/detail/io.hpp

   1 //
   2 // ssl/detail/io.hpp
   3 // ~~~~~~~~~~~~~~~~~
   4 //
   5 // Copyright (c) 2003-2017 Christopher M. Kohlhoff (chris at kohlhoff dot com)
   6 //
   7 // Distributed under the Boost Software License, Version 1.0. (See accompanying
   8 // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
   9 //
  10
  11 #ifndef BOOST_ASIO_SSL_DETAIL_IO_HPP
  12 #define BOOST_ASIO_SSL_DETAIL_IO_HPP
  13
  14 #if defined(_MSC_VER) && (_MSC_VER >= 1200)
  15 # pragma once
  16 #endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
  17
  18 #include <boost/asio/detail/config.hpp>
  19
  20 #if !defined(BOOST_ASIO_ENABLE_OLD_SSL)
  21 # include <boost/asio/ssl/detail/engine.hpp>
  22 # include <boost/asio/ssl/detail/stream_core.hpp>
  23 # include <boost/asio/write.hpp>
  24 #endif // !defined(BOOST_ASIO_ENABLE_OLD_SSL)
  25
  26 #include <boost/asio/detail/push_options.hpp>
  27
  28 namespace boost {
  29 namespace asio {
  30 namespace ssl {
  31 namespace detail {
  32
  33 #if !defined(BOOST_ASIO_ENABLE_OLD_SSL)
  34
  35 template <typename Stream, typename Operation>
  36 std::size_t io(Stream& next_layer, stream_core& core,
  37     const Operation& op, boost::system::error_code& ec)
  38 {
  39   std::size_t bytes_transferred = 0;
  40   do switch (op(core.engine_, ec, bytes_transferred))
  41   {
  42   case engine::want_input_and_retry:
  43
  44     // If the input buffer is empty then we need to read some more data from
  45     // the underlying transport.
  46     if (boost::asio::buffer_size(core.input_) == 0)
  47       core.input_ = boost::asio::buffer(core.input_buffer_,
  48           next_layer.read_some(core.input_buffer_, ec));
  49
  50     // Pass the new input data to the engine.
  51     core.input_ = core.engine_.put_input(core.input_);
  52
  53     // Try the operation again.
  54     continue;
  55
  56   case engine::want_output_and_retry:
  57
  58     // Get output data from the engine and write it to the underlying
  59     // transport.
  60     boost::asio::write(next_layer,
  61         core.engine_.get_output(core.output_buffer_), ec);
  62
  63     // Try the operation again.
  64     continue;
  65
  66   case engine::want_output:
  67
  68     // Get output data from the engine and write it to the underlying
  69     // transport.
  70     boost::asio::write(next_layer,
  71         core.engine_.get_output(core.output_buffer_), ec);
  72
  73     // Operation is complete. Return result to caller.
  74     core.engine_.map_error_code(ec);
  75     return bytes_transferred;
  76
  77   default:
  78
  79     // Operation is complete. Return result to caller.
  80     core.engine_.map_error_code(ec);
  81     return bytes_transferred;
  82
  83   } while (!ec);
  84
  85   // Operation failed. Return result to caller.
  86   core.engine_.map_error_code(ec);
  87   return 0;
  88 }
  89
  90 template <typename Stream, typename Operation, typename Handler>
  91 class io_op
  92 {
  93 public:
  94   io_op(Stream& next_layer, stream_core& core,
  95       const Operation& op, Handler& handler)
  96     : next_layer_(next_layer),
  97       core_(core),
  98       op_(op),
  99       start_(0),
 100       want_(engine::want_nothing),
 101       bytes_transferred_(0),
 102       handler_(BOOST_ASIO_MOVE_CAST(Handler)(handler))
 103   {
 104   }
 105
 106 #if defined(BOOST_ASIO_HAS_MOVE)
 107   io_op(const io_op& other)
 108     : next_layer_(other.next_layer_),
 109       core_(other.core_),
 110       op_(other.op_),
 111       start_(other.start_),
 112       want_(other.want_),
 113       ec_(other.ec_),
 114       bytes_transferred_(other.bytes_transferred_),
 115       handler_(other.handler_)
 116   {
 117   }
 118
 119   io_op(io_op&& other)
 120     : next_layer_(other.next_layer_),
 121       core_(other.core_),
 122       op_(other.op_),
 123       start_(other.start_),
 124       want_(other.want_),
 125       ec_(other.ec_),
 126       bytes_transferred_(other.bytes_transferred_),
 127       handler_(BOOST_ASIO_MOVE_CAST(Handler)(other.handler_))
 128   {
 129   }
 130 #endif // defined(BOOST_ASIO_HAS_MOVE)
 131
 132   void operator()(boost::system::error_code ec,
 133       std::size_t bytes_transferred = ~std::size_t(0), int start = 0)
 134   {
 135     switch (start_ = start)
 136     {
 137     case 1: // Called after at least one async operation.
 138       do
 139       {
 140         switch (want_ = op_(core_.engine_, ec_, bytes_transferred_))
 141         {
 142         case engine::want_input_and_retry:
 143
 144           // If the input buffer already has data in it we can pass it to the
 145           // engine and then retry the operation immediately.
 146           if (boost::asio::buffer_size(core_.input_) != 0)
 147           {
 148             core_.input_ = core_.engine_.put_input(core_.input_);
 149             continue;
 150           }
 151
 152           // The engine wants more data to be read from input. However, we
 153           // cannot allow more than one read operation at a time on the
 154           // underlying transport. The pending_read_ timer's expiry is set to
 155           // pos_infin if a read is in progress, and neg_infin otherwise.
 156           if (core_.pending_read_.expires_at() == core_.neg_infin())
 157           {
 158             // Prevent other read operations from being started.
 159             core_.pending_read_.expires_at(core_.pos_infin());
 160
 161             // Start reading some data from the underlying transport.
 162             next_layer_.async_read_some(
 163                 boost::asio::buffer(core_.input_buffer_),
 164                 BOOST_ASIO_MOVE_CAST(io_op)(*this));
 165           }
 166           else
 167           {
 168             // Wait until the current read operation completes.
 169             core_.pending_read_.async_wait(BOOST_ASIO_MOVE_CAST(io_op)(*this));
 170           }
 171
 172           // Yield control until asynchronous operation completes. Control
 173           // resumes at the "default:" label below.
 174           return;
 175
 176         case engine::want_output_and_retry:
 177         case engine::want_output:
 178
 179           // The engine wants some data to be written to the output. However, we
 180           // cannot allow more than one write operation at a time on the
 181           // underlying transport. The pending_write_ timer's expiry is set to
 182           // pos_infin if a write is in progress, and neg_infin otherwise.
 183           if (core_.pending_write_.expires_at() == core_.neg_infin())
 184           {
 185             // Prevent other write operations from being started.
 186             core_.pending_write_.expires_at(core_.pos_infin());
 187
 188             // Start writing all the data to the underlying transport.
 189             boost::asio::async_write(next_layer_,
 190                 core_.engine_.get_output(core_.output_buffer_),
 191                 BOOST_ASIO_MOVE_CAST(io_op)(*this));
 192           }
 193           else
 194           {
 195             // Wait until the current write operation completes.
 196             core_.pending_write_.async_wait(BOOST_ASIO_MOVE_CAST(io_op)(*this));
 197           }
 198
 199           // Yield control until asynchronous operation completes. Control
 200           // resumes at the "default:" label below.
 201           return;
 202
 203         default:
 204
 205           // The SSL operation is done and we can invoke the handler, but we
 206           // have to keep in mind that this function might be being called from
 207           // the async operation's initiating function. In this case we're not
 208           // allowed to call the handler directly. Instead, issue a zero-sized
 209           // read so the handler runs "as-if" posted using io_service::post().
 210           if (start)
 211           {
 212             next_layer_.async_read_some(
 213                 boost::asio::buffer(core_.input_buffer_, 0),
 214                 BOOST_ASIO_MOVE_CAST(io_op)(*this));
 215
 216             // Yield control until asynchronous operation completes. Control
 217             // resumes at the "default:" label below.
 218             return;
 219           }
 220           else
 221           {
 222             // Continue on to run handler directly.
 223             break;
 224           }
 225         }
 226
 227         default:
 228         if (bytes_transferred == ~std::size_t(0))
 229           bytes_transferred = 0; // Timer cancellation, no data transferred.
 230         else if (!ec_)
 231           ec_ = ec;
 232
 233         switch (want_)
 234         {
 235         case engine::want_input_and_retry:
 236
 237           // Add received data to the engine's input.
 238           core_.input_ = boost::asio::buffer(
 239               core_.input_buffer_, bytes_transferred);
 240           core_.input_ = core_.engine_.put_input(core_.input_);
 241
 242           // Release any waiting read operations.
 243           core_.pending_read_.expires_at(core_.neg_infin());
 244
 245           // Try the operation again.
 246           continue;
 247
 248         case engine::want_output_and_retry:
 249
 250           // Release any waiting write operations.
 251           core_.pending_write_.expires_at(core_.neg_infin());
 252
 253           // Try the operation again.
 254           continue;
 255
 256         case engine::want_output:
 257
 258           // Release any waiting write operations.
 259           core_.pending_write_.expires_at(core_.neg_infin());
 260
 261           // Fall through to call handler.
 262
 263         default:
 264
 265           // Pass the result to the handler.
 266           op_.call_handler(handler_,
 267               core_.engine_.map_error_code(ec_),
 268               ec_ ? 0 : bytes_transferred_);
 269
 270           // Our work here is done.
 271           return;
 272         }
 273       } while (!ec_);
 274
 275       // Operation failed. Pass the result to the handler.
 276       op_.call_handler(handler_, core_.engine_.map_error_code(ec_), 0);
 277     }
 278   }
 279
 280 //private:
 281   Stream& next_layer_;
 282   stream_core& core_;
 283   Operation op_;
 284   int start_;
 285   engine::want want_;
 286   boost::system::error_code ec_;
 287   std::size_t bytes_transferred_;
 288   Handler handler_;
 289 };
 290
 291 template <typename Stream, typename Operation,  typename Handler>
 292 inline void* asio_handler_allocate(std::size_t size,
 293     io_op<Stream, Operation, Handler>* this_handler)
 294 {
 295   return boost_asio_handler_alloc_helpers::allocate(
 296       size, this_handler->handler_);
 297 }
 298
 299 template <typename Stream, typename Operation, typename Handler>
 300 inline void asio_handler_deallocate(void* pointer, std::size_t size,
 301     io_op<Stream, Operation, Handler>* this_handler)
 302 {
 303   boost_asio_handler_alloc_helpers::deallocate(
 304       pointer, size, this_handler->handler_);
 305 }
 306
 307 template <typename Stream, typename Operation, typename Handler>
 308 inline bool asio_handler_is_continuation(
 309     io_op<Stream, Operation, Handler>* this_handler)
 310 {
 311   return this_handler->start_ == 0 ? true
 312     : boost_asio_handler_cont_helpers::is_continuation(this_handler->handler_);
 313 }
 314
 315 template <typename Function, typename Stream,
 316     typename Operation, typename Handler>
 317 inline void asio_handler_invoke(Function& function,
 318     io_op<Stream, Operation, Handler>* this_handler)
 319 {
 320   boost_asio_handler_invoke_helpers::invoke(
 321       function, this_handler->handler_);
 322 }
 323
 324 template <typename Function, typename Stream,
 325     typename Operation, typename Handler>
 326 inline void asio_handler_invoke(const Function& function,
 327     io_op<Stream, Operation, Handler>* this_handler)
 328 {
 329   boost_asio_handler_invoke_helpers::invoke(
 330       function, this_handler->handler_);
 331 }
 332
 333 template <typename Stream, typename Operation, typename Handler>
 334 inline void async_io(Stream& next_layer, stream_core& core,
 335     const Operation& op, Handler& handler)
 336 {
 337   io_op<Stream, Operation, Handler>(
 338     next_layer, core, op, handler)(
 339       boost::system::error_code(), 0, 1);
 340 }
 341
 342 #endif // !defined(BOOST_ASIO_ENABLE_OLD_SSL)
 343
 344 } // namespace detail
 345 } // namespace ssl
 346 } // namespace asio
 347 } // namespace boost
 348
 349 #include <boost/asio/detail/pop_options.hpp>
 350
 351 #endif // BOOST_ASIO_SSL_DETAIL_IO_HPP