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transmission/libtransmission/peer-io.h

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10 KiB
C++

// This file Copyright © Mnemosyne LLC.
// It may be used under GPLv2 (SPDX: GPL-2.0-only), GPLv3 (SPDX: GPL-3.0-only),
// or any future license endorsed by Mnemosyne LLC.
// License text can be found in the licenses/ folder.
#pragma once
#ifndef __TRANSMISSION__
#error only libtransmission should #include this header.
#endif
#include <algorithm>
#include <cstddef> // size_t
#include <cstdint> // uintX_t
#include <deque>
#include <memory>
#include <utility> // std::pair
#include <event2/util.h> // for evutil_socket_t
#include "libtransmission/transmission.h"
#include "libtransmission/bandwidth.h"
#include "libtransmission/block-info.h"
#include "libtransmission/net.h" // tr_address
#include "libtransmission/peer-mse.h"
#include "libtransmission/peer-socket.h"
#include "libtransmission/tr-buffer.h"
#include "libtransmission/tr-macros.h" // tr_sha1_digest_t, TR_CONSTEXPR20
#include "libtransmission/utils-ev.h"
struct struct_utp_context;
struct tr_error;
struct tr_session;
namespace libtransmission::test
{
class HandshakeTest;
} // namespace libtransmission::test
enum ReadState
{
READ_NOW,
READ_LATER,
READ_ERR
};
enum tr_preferred_transport : uint8_t
{
// More preferred transports goes on top
TR_PREFER_UTP,
TR_PREFER_TCP,
TR_NUM_PREFERRED_TRANSPORT
};
class tr_peerIo final : public std::enable_shared_from_this<tr_peerIo>
{
using DH = tr_message_stream_encryption::DH;
using Filter = tr_message_stream_encryption::Filter;
using CanRead = ReadState (*)(tr_peerIo* io, void* user_data, size_t* setme_piece_byte_count);
using DidWrite = void (*)(tr_peerIo* io, size_t bytesWritten, bool wasPieceData, void* userData);
using GotError = void (*)(tr_peerIo* io, tr_error const& error, void* userData);
public:
tr_peerIo(
tr_session* session_in,
tr_sha1_digest_t const* info_hash,
bool is_incoming,
bool is_seed,
tr_bandwidth* parent_bandwidth);
~tr_peerIo();
static std::shared_ptr<tr_peerIo> new_outgoing(
tr_session* session,
tr_bandwidth* parent,
tr_socket_address const& socket_address,
tr_sha1_digest_t const& info_hash,
bool is_seed,
bool utp);
static std::shared_ptr<tr_peerIo> new_incoming(tr_session* session, tr_bandwidth* parent, tr_peer_socket socket);
constexpr void set_callbacks(CanRead can_read, DidWrite did_write, GotError got_error, void* user_data)
{
can_read_ = can_read;
did_write_ = did_write;
got_error_ = got_error;
user_data_ = user_data;
}
constexpr void clear_callbacks()
{
set_callbacks(nullptr, nullptr, nullptr, nullptr);
}
void set_socket(tr_peer_socket);
[[nodiscard]] constexpr auto is_utp() const noexcept
{
return socket_.is_utp();
}
void clear();
[[nodiscard]] bool reconnect();
void set_enabled(tr_direction dir, bool is_enabled);
///
[[nodiscard]] TR_CONSTEXPR20 auto read_buffer_size() const noexcept
{
return std::size(inbuf_);
}
template<typename T>
[[nodiscard]] auto read_buffer_starts_with(T const& t) const noexcept
{
return inbuf_.starts_with(t);
}
void read_buffer_discard(size_t n_bytes)
{
read_bytes(nullptr, n_bytes);
}
void read_bytes(void* bytes, size_t n_bytes);
void read_uint8(uint8_t* setme)
{
read_bytes(setme, sizeof(uint8_t));
}
void read_uint16(uint16_t* setme);
void read_uint32(uint32_t* setme);
///
[[nodiscard]] size_t get_write_buffer_space(uint64_t now) const noexcept;
void write_bytes(void const* bytes, size_t n_bytes, bool is_piece_data)
{
outbuf_info_.emplace_back(n_bytes, is_piece_data);
auto [resbuf, reslen] = outbuf_.reserve_space(n_bytes);
filter_.encrypt(reinterpret_cast<std::byte const*>(bytes), n_bytes, resbuf);
outbuf_.commit_space(n_bytes);
}
// Write all the data from `buf`.
// This is a destructive add: `buf` is empty after this call.
template<typename T>
void write(libtransmission::BufferReader<T>& buf, bool is_piece_data)
{
auto const n_bytes = std::size(buf);
write_bytes(std::data(buf), n_bytes, is_piece_data);
buf.drain(n_bytes);
}
size_t flush_outgoing_protocol_msgs();
size_t flush(tr_direction dir, size_t byte_limit);
///
[[nodiscard]] auto has_bandwidth_left(tr_direction dir) const noexcept
{
return bandwidth_.clamp(dir, 1024) > 0;
}
[[nodiscard]] auto get_piece_speed_bytes_per_second(uint64_t now, tr_direction dir) const noexcept
{
return bandwidth_.get_piece_speed_bytes_per_second(now, dir);
}
///
[[nodiscard]] constexpr auto supports_fext() const noexcept
{
return fast_extension_supported_;
}
constexpr void set_supports_fext(bool flag) noexcept
{
fast_extension_supported_ = flag;
}
///
[[nodiscard]] constexpr auto supports_ltep() const noexcept
{
return extended_protocol_supported_;
}
constexpr void set_supports_ltep(bool flag) noexcept
{
extended_protocol_supported_ = flag;
}
///
[[nodiscard]] constexpr auto supports_dht() const noexcept
{
return dht_supported_;
}
constexpr void set_supports_dht(bool flag) noexcept
{
dht_supported_ = flag;
}
///
[[nodiscard]] constexpr auto const& bandwidth() const noexcept
{
return bandwidth_;
}
[[nodiscard]] constexpr auto& bandwidth() noexcept
{
return bandwidth_;
}
void set_bandwidth(tr_bandwidth* parent)
{
bandwidth_.set_parent(parent);
}
///
[[nodiscard]] constexpr auto const& torrent_hash() const noexcept
{
return info_hash_;
}
void set_torrent_hash(tr_sha1_digest_t const& hash) noexcept
{
info_hash_ = hash;
}
///
[[nodiscard]] constexpr auto priority() const noexcept
{
return priority_;
}
constexpr void set_priority(tr_priority_t priority)
{
priority_ = priority;
}
///
[[nodiscard]] constexpr auto supports_utp() const noexcept
{
return utp_supported_;
}
[[nodiscard]] constexpr auto is_incoming() const noexcept
{
return is_incoming_;
}
[[nodiscard]] constexpr auto const& address() const noexcept
{
return socket_.address();
}
[[nodiscard]] constexpr auto const& socket_address() const noexcept
{
return socket_.socket_address();
}
[[nodiscard]] auto display_name() const
{
return socket_.display_name();
}
///
[[nodiscard]] constexpr auto is_encrypted() const noexcept
{
return filter_.is_active();
}
void decrypt_init(bool is_incoming, DH const& dh, tr_sha1_digest_t const& info_hash)
{
decrypt_remain_len_.reset();
filter_.decrypt_init(is_incoming, dh, info_hash);
}
TR_CONSTEXPR20 void decrypt_disable(size_t decrypt_len = 0U) noexcept
{
// optionally decrypt decrypt_len more bytes before disabling decryption
decrypt_remain_len_ = decrypt_len;
}
void encrypt_init(bool is_incoming, DH const& dh, tr_sha1_digest_t const& info_hash)
{
filter_.encrypt_init(is_incoming, dh, info_hash);
}
constexpr void encrypt_disable() noexcept
{
// unlike the read buffer, we don't need to "encrypt xxx
// more bytes before disabling encryption" since we control
// whether we add data before or after calling encrypt_disable()
filter_.encrypt_disable();
}
///
static void utp_init(struct_utp_context* ctx);
private:
// Our target socket receive buffer size.
// Gets read from the socket buffer into the PeerBuffer inbuf_.
static constexpr auto RcvBuf = size_t{ 256 * 1024 };
// The buffer size for incoming & outgoing peer messages.
// Starts off with enough capacity to read a single BT Piece message,
// but has a 5x GrowthFactor so that it can quickly to high volume.
using PeerBuffer = libtransmission::StackBuffer<tr_block_info::BlockSize + 16U, std::byte, std::ratio<5, 1>>;
friend class libtransmission::test::HandshakeTest;
[[nodiscard]] constexpr auto is_seed() const noexcept
{
return is_seed_;
}
void call_error_callback(tr_error const& error)
{
if (got_error_ != nullptr)
{
got_error_(this, error, user_data_);
}
}
void on_utp_state_change(int new_state);
void on_utp_error(int errcode);
void close();
static void event_read_cb(evutil_socket_t fd, short /*event*/, void* vio);
static void event_write_cb(evutil_socket_t fd, short /*event*/, void* vio);
void event_enable(short event);
void event_disable(short event);
void can_read_wrapper();
void did_write_wrapper(size_t bytes_transferred);
size_t try_read(size_t max);
size_t try_write(size_t max);
// this is only public for testing purposes.
// production code should use new_outgoing() or new_incoming()
static std::shared_ptr<tr_peerIo> create(
tr_session* session,
tr_bandwidth* parent,
tr_sha1_digest_t const* info_hash,
bool is_incoming,
bool is_seed);
Filter filter_;
std::optional<size_t> decrypt_remain_len_;
std::deque<std::pair<size_t /*n_bytes*/, bool /*is_piece_data*/>> outbuf_info_;
tr_peer_socket socket_ = {};
tr_bandwidth bandwidth_;
tr_sha1_digest_t info_hash_;
PeerBuffer inbuf_;
PeerBuffer outbuf_;
tr_session* const session_;
CanRead can_read_ = nullptr;
DidWrite did_write_ = nullptr;
GotError got_error_ = nullptr;
void* user_data_ = nullptr;
libtransmission::evhelpers::event_unique_ptr event_read_;
libtransmission::evhelpers::event_unique_ptr event_write_;
short int pending_events_ = 0;
tr_priority_t priority_ = TR_PRI_NORMAL;
bool const is_seed_;
bool const is_incoming_;
bool utp_supported_ = false;
bool dht_supported_ = false;
bool extended_protocol_supported_ = false;
bool fast_extension_supported_ = false;
};