136 lines
4.9 KiB
C++
136 lines
4.9 KiB
C++
// Copyright (c) 2019-2020, The Monero Project
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//
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// All rights reserved.
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//
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// Redistribution and use in source and binary forms, with or without modification, are
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// permitted provided that the following conditions are met:
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//
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// 1. Redistributions of source code must retain the above copyright notice, this list of
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// conditions and the following disclaimer.
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//
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// 2. Redistributions in binary form must reproduce the above copyright notice, this list
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// of conditions and the following disclaimer in the documentation and/or other
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// materials provided with the distribution.
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//
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// 3. Neither the name of the copyright holder nor the names of its contributors may be
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// used to endorse or promote products derived from this software without specific
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// prior written permission.
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//
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// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY
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// EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
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// MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
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// THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
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// PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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// INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
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// STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF
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// THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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#include "net/levin_base.h"
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#include "int-util.h"
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namespace epee
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{
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namespace levin
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{
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message_writer::message_writer(const std::size_t reserve)
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: buffer()
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{
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buffer.reserve(reserve);
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buffer.put_n(0, sizeof(header));
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}
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byte_slice message_writer::finalize(const uint32_t command, const uint32_t flags, const uint32_t return_code, const bool expect_response)
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{
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if (buffer.size() < sizeof(header))
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throw std::runtime_error{"levin_writer::finalize already called"};
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header head = make_header(command, payload_size(), flags, expect_response);
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head.m_return_code = SWAP32LE(return_code);
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std::memcpy(buffer.tellp() - buffer.size(), std::addressof(head), sizeof(head));
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return byte_slice{std::move(buffer)};
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}
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bucket_head2 make_header(uint32_t command, uint64_t msg_size, uint32_t flags, bool expect_response) noexcept
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{
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bucket_head2 head = {0};
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head.m_signature = SWAP64LE(LEVIN_SIGNATURE);
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head.m_have_to_return_data = expect_response;
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head.m_cb = SWAP64LE(msg_size);
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head.m_command = SWAP32LE(command);
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head.m_protocol_version = SWAP32LE(LEVIN_PROTOCOL_VER_1);
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head.m_flags = SWAP32LE(flags);
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return head;
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}
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byte_slice make_noise_notify(const std::size_t noise_bytes)
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{
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static constexpr const std::uint32_t flags =
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LEVIN_PACKET_BEGIN | LEVIN_PACKET_END;
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if (noise_bytes < sizeof(bucket_head2))
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return nullptr;
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std::string buffer(noise_bytes, char(0));
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const bucket_head2 head = make_header(0, noise_bytes - sizeof(bucket_head2), flags, false);
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std::memcpy(std::addressof(buffer[0]), std::addressof(head), sizeof(head));
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return byte_slice{std::move(buffer)};
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}
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byte_slice make_fragmented_notify(const std::size_t noise_size, const int command, message_writer message)
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{
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if (noise_size < sizeof(bucket_head2) * 2)
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return nullptr;
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if (message.buffer.size() <= noise_size)
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{
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/* The entire message can be sent at once, and the levin binary parser
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will ignore extra bytes. So just pad with zeroes and otherwise send
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a "normal", not fragmented message. */
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message.buffer.put_n(0, noise_size - message.buffer.size());
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return message.finalize_notify(command);
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}
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// fragment message
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const byte_slice payload_bytes = message.finalize_notify(command);
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span<const std::uint8_t> payload = to_span(payload_bytes);
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const size_t payload_space = noise_size - sizeof(bucket_head2);
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const size_t expected_fragments = ((payload.size() - 2) / payload_space) + 1;
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byte_stream buffer{};
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buffer.reserve(expected_fragments * noise_size);
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bucket_head2 head = make_header(0, payload_space, LEVIN_PACKET_BEGIN, false);
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buffer.write(as_byte_span(head));
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// internal levin header is in payload already
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size_t copy_size = payload.remove_prefix(payload_space);
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buffer.write(payload.data() - copy_size, copy_size);
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head.m_flags = 0;
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while (!payload.empty())
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{
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copy_size = payload.remove_prefix(payload_space);
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if (payload.empty())
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head.m_flags = LEVIN_PACKET_END;
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buffer.write(as_byte_span(head));
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buffer.write(payload.data() - copy_size, copy_size);
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}
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const size_t padding = noise_size - copy_size - sizeof(bucket_head2);
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buffer.put_n(0, padding);
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return byte_slice{std::move(buffer)};
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}
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} // levin
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} // epee
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