//
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// Copyright (c) 2016-2019 Vinnie Falco (vinnie dot falco at gmail dot com)
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//
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// Distributed under the Boost Software License, Version 1.0. (See accompanying
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// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
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//
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// Official repository: https://github.com/boostorg/beast
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//
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#ifndef BOOST_BEAST_WEBSOCKET_DETAIL_IMPL_BASE_HPP
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#define BOOST_BEAST_WEBSOCKET_DETAIL_IMPL_BASE_HPP
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#include <boost/beast/websocket/option.hpp>
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#include <boost/beast/websocket/detail/frame.hpp>
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#include <boost/beast/websocket/detail/pmd_extension.hpp>
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#include <boost/beast/core/buffer_traits.hpp>
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#include <boost/beast/core/role.hpp>
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#include <boost/beast/http/empty_body.hpp>
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#include <boost/beast/http/message.hpp>
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#include <boost/beast/http/string_body.hpp>
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#include <boost/beast/zlib/deflate_stream.hpp>
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#include <boost/beast/zlib/inflate_stream.hpp>
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#include <boost/beast/core/buffers_suffix.hpp>
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#include <boost/beast/core/error.hpp>
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#include <boost/beast/core/detail/clamp.hpp>
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#include <boost/asio/buffer.hpp>
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#include <cstdint>
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#include <memory>
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#include <stdexcept>
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namespace boost {
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namespace beast {
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namespace websocket {
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namespace detail {
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//------------------------------------------------------------------------------
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template<bool deflateSupported>
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struct impl_base;
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template<>
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struct impl_base<true>
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{
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// State information for the permessage-deflate extension
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struct pmd_type
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{
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// `true` if current read message is compressed
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bool rd_set = false;
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zlib::deflate_stream zo;
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zlib::inflate_stream zi;
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};
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std::unique_ptr<pmd_type> pmd_; // pmd settings or nullptr
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permessage_deflate pmd_opts_; // local pmd options
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detail::pmd_offer pmd_config_; // offer (client) or negotiation (server)
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// return `true` if current message is deflated
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bool
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rd_deflated() const
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{
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return pmd_ && pmd_->rd_set;
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}
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// set whether current message is deflated
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// returns `false` on protocol violation
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bool
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rd_deflated(bool rsv1)
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{
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if(pmd_)
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{
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pmd_->rd_set = rsv1;
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return true;
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}
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return ! rsv1; // pmd not negotiated
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}
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// Compress a buffer sequence
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// Returns: `true` if more calls are needed
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//
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template<class ConstBufferSequence>
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bool
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deflate(
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net::mutable_buffer& out,
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buffers_suffix<ConstBufferSequence>& cb,
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bool fin,
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std::size_t& total_in,
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error_code& ec)
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{
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BOOST_ASSERT(out.size() >= 6);
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auto& zo = this->pmd_->zo;
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zlib::z_params zs;
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zs.avail_in = 0;
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zs.next_in = nullptr;
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zs.avail_out = out.size();
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zs.next_out = out.data();
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for(auto in : beast::buffers_range_ref(cb))
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{
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zs.avail_in = in.size();
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if(zs.avail_in == 0)
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continue;
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zs.next_in = in.data();
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zo.write(zs, zlib::Flush::none, ec);
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if(ec)
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{
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if(ec != zlib::error::need_buffers)
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return false;
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BOOST_ASSERT(zs.avail_out == 0);
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BOOST_ASSERT(zs.total_out == out.size());
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ec = {};
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break;
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}
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if(zs.avail_out == 0)
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{
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BOOST_ASSERT(zs.total_out == out.size());
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break;
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}
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BOOST_ASSERT(zs.avail_in == 0);
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}
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total_in = zs.total_in;
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cb.consume(zs.total_in);
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if(zs.avail_out > 0 && fin)
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{
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auto const remain = buffer_bytes(cb);
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if(remain == 0)
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{
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// Inspired by Mark Adler
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// https://github.com/madler/zlib/issues/149
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//
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// VFALCO We could do this flush twice depending
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// on how much space is in the output.
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zo.write(zs, zlib::Flush::block, ec);
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BOOST_ASSERT(! ec || ec == zlib::error::need_buffers);
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if(ec == zlib::error::need_buffers)
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ec = {};
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if(ec)
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return false;
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if(zs.avail_out >= 6)
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{
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zo.write(zs, zlib::Flush::full, ec);
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BOOST_ASSERT(! ec);
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// remove flush marker
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zs.total_out -= 4;
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out = net::buffer(out.data(), zs.total_out);
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return false;
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}
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}
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}
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ec = {};
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out = net::buffer(out.data(), zs.total_out);
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return true;
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}
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void
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do_context_takeover_write(role_type role)
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{
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if((role == role_type::client &&
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this->pmd_config_.client_no_context_takeover) ||
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(role == role_type::server &&
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this->pmd_config_.server_no_context_takeover))
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{
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this->pmd_->zo.reset();
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}
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}
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void
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inflate(
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zlib::z_params& zs,
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zlib::Flush flush,
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error_code& ec)
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{
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pmd_->zi.write(zs, flush, ec);
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}
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void
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do_context_takeover_read(role_type role)
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{
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if((role == role_type::client &&
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pmd_config_.server_no_context_takeover) ||
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(role == role_type::server &&
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pmd_config_.client_no_context_takeover))
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{
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pmd_->zi.clear();
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}
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}
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template<class Body, class Allocator>
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void
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build_response_pmd(
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http::response<http::string_body>& res,
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http::request<Body,
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http::basic_fields<Allocator>> const& req);
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void
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on_response_pmd(
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http::response<http::string_body> const& res)
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{
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detail::pmd_offer offer;
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detail::pmd_read(offer, res);
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// VFALCO see if offer satisfies pmd_config_,
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// return an error if not.
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pmd_config_ = offer; // overwrite for now
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}
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template<class Allocator>
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void
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do_pmd_config(
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http::basic_fields<Allocator> const& h)
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{
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detail::pmd_read(pmd_config_, h);
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}
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void
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set_option_pmd(permessage_deflate const& o)
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{
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if( o.server_max_window_bits > 15 ||
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o.server_max_window_bits < 9)
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BOOST_THROW_EXCEPTION(std::invalid_argument{
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"invalid server_max_window_bits"});
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if( o.client_max_window_bits > 15 ||
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o.client_max_window_bits < 9)
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BOOST_THROW_EXCEPTION(std::invalid_argument{
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"invalid client_max_window_bits"});
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if( o.compLevel < 0 ||
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o.compLevel > 9)
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BOOST_THROW_EXCEPTION(std::invalid_argument{
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"invalid compLevel"});
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if( o.memLevel < 1 ||
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o.memLevel > 9)
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BOOST_THROW_EXCEPTION(std::invalid_argument{
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"invalid memLevel"});
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pmd_opts_ = o;
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}
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void
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get_option_pmd(permessage_deflate& o)
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{
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o = pmd_opts_;
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}
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void
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build_request_pmd(http::request<http::empty_body>& req)
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{
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if(pmd_opts_.client_enable)
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{
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detail::pmd_offer config;
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config.accept = true;
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config.server_max_window_bits =
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pmd_opts_.server_max_window_bits;
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config.client_max_window_bits =
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pmd_opts_.client_max_window_bits;
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config.server_no_context_takeover =
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pmd_opts_.server_no_context_takeover;
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config.client_no_context_takeover =
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pmd_opts_.client_no_context_takeover;
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detail::pmd_write(req, config);
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}
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}
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void
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open_pmd(role_type role)
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{
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if(((role == role_type::client &&
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pmd_opts_.client_enable) ||
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(role == role_type::server &&
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pmd_opts_.server_enable)) &&
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pmd_config_.accept)
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{
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detail::pmd_normalize(pmd_config_);
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pmd_.reset(::new pmd_type);
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if(role == role_type::client)
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{
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pmd_->zi.reset(
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pmd_config_.server_max_window_bits);
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pmd_->zo.reset(
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pmd_opts_.compLevel,
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pmd_config_.client_max_window_bits,
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pmd_opts_.memLevel,
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zlib::Strategy::normal);
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}
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else
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{
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pmd_->zi.reset(
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pmd_config_.client_max_window_bits);
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pmd_->zo.reset(
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pmd_opts_.compLevel,
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pmd_config_.server_max_window_bits,
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pmd_opts_.memLevel,
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zlib::Strategy::normal);
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}
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}
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}
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void close_pmd()
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{
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pmd_.reset();
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}
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bool pmd_enabled() const
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{
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return pmd_ != nullptr;
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}
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std::size_t
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read_size_hint_pmd(
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std::size_t initial_size,
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bool rd_done,
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std::uint64_t rd_remain,
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detail::frame_header const& rd_fh) const
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{
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using beast::detail::clamp;
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std::size_t result;
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BOOST_ASSERT(initial_size > 0);
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if(! pmd_ || (! rd_done && ! pmd_->rd_set))
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{
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// current message is uncompressed
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if(rd_done)
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{
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// first message frame
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result = initial_size;
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goto done;
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}
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else if(rd_fh.fin)
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{
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// last message frame
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BOOST_ASSERT(rd_remain > 0);
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result = clamp(rd_remain);
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goto done;
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}
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}
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result = (std::max)(
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initial_size, clamp(rd_remain));
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done:
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BOOST_ASSERT(result != 0);
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return result;
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}
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};
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//------------------------------------------------------------------------------
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template<>
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struct impl_base<false>
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{
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// These stubs are for avoiding linking in the zlib
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// code when permessage-deflate is not enabled.
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bool
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rd_deflated() const
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{
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return false;
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}
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bool
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rd_deflated(bool rsv1)
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{
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return ! rsv1;
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}
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template<class ConstBufferSequence>
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bool
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deflate(
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net::mutable_buffer&,
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buffers_suffix<ConstBufferSequence>&,
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bool,
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std::size_t&,
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error_code&)
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{
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return false;
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}
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void
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do_context_takeover_write(role_type)
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{
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}
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void
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inflate(
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zlib::z_params&,
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zlib::Flush,
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error_code&)
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{
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}
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void
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do_context_takeover_read(role_type)
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{
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}
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template<class Body, class Allocator>
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void
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build_response_pmd(
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http::response<http::string_body>&,
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http::request<Body,
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http::basic_fields<Allocator>> const&);
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void
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on_response_pmd(
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http::response<http::string_body> const&)
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{
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}
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template<class Allocator>
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void
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do_pmd_config(http::basic_fields<Allocator> const&)
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{
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}
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void
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set_option_pmd(permessage_deflate const& o)
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{
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if(o.client_enable || o.server_enable)
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{
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// Can't enable permessage-deflate
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// when deflateSupported == false.
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//
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BOOST_THROW_EXCEPTION(std::invalid_argument{
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"deflateSupported == false"});
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}
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}
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void
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get_option_pmd(permessage_deflate& o)
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{
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o = {};
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o.client_enable = false;
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o.server_enable = false;
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}
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void
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build_request_pmd(
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http::request<http::empty_body>&)
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{
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}
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void open_pmd(role_type)
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{
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}
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void close_pmd()
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{
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}
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bool pmd_enabled() const
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{
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return false;
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}
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std::size_t
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read_size_hint_pmd(
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std::size_t initial_size,
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bool rd_done,
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std::uint64_t rd_remain,
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frame_header const& rd_fh) const
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{
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using beast::detail::clamp;
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std::size_t result;
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BOOST_ASSERT(initial_size > 0);
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// compression is not supported
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if(rd_done)
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{
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// first message frame
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result = initial_size;
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}
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else if(rd_fh.fin)
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{
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// last message frame
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BOOST_ASSERT(rd_remain > 0);
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result = clamp(rd_remain);
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}
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else
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{
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result = (std::max)(
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initial_size, clamp(rd_remain));
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}
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BOOST_ASSERT(result != 0);
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return result;
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}
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};
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} // detail
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} // websocket
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} // beast
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} // boost
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#endif
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