147 lines
4.1 KiB
C++
147 lines
4.1 KiB
C++
// This file Copyright © Mnemosyne LLC.
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// It may be used under GPLv2 (SPDX: GPL-2.0-only), GPLv3 (SPDX: GPL-3.0-only),
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// or any future license endorsed by Mnemosyne LLC.
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// License text can be found in the licenses/ folder.
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#pragma once
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#ifndef __TRANSMISSION__
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#error only libtransmission should #include this header.
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#endif
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#include <atomic>
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#include <cstddef> // size_t
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#include <string>
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#include <utility> // for std::make_pair()
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#include "libtransmission/net.h"
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#include "libtransmission/tr-buffer.h"
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struct UTPSocket;
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struct tr_session;
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class tr_peer_socket
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{
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public:
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using InBuf = libtransmission::BufferWriter<std::byte>;
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using OutBuf = libtransmission::BufferReader<std::byte>;
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tr_peer_socket() = default;
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tr_peer_socket(tr_session const* session, tr_socket_address const& socket_address, tr_socket_t sock);
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tr_peer_socket(tr_socket_address const& socket_address, struct UTPSocket* sock);
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tr_peer_socket(tr_peer_socket&& s) noexcept
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{
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*this = std::move(s);
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}
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tr_peer_socket(tr_peer_socket const&) = delete;
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tr_peer_socket& operator=(tr_peer_socket&& s) noexcept
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{
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close();
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handle = s.handle;
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socket_address_ = s.socket_address_;
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type_ = s.type_;
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// invalidate s.type_, s.handle so s.close() won't break anything
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s.type_ = Type::None;
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s.handle = {};
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return *this;
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}
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tr_peer_socket& operator=(tr_peer_socket const&) = delete;
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~tr_peer_socket()
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{
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close();
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}
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void close();
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size_t try_read(InBuf& buf, size_t max, bool buf_is_empty, tr_error* error) const;
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size_t try_write(OutBuf& buf, size_t max, tr_error* error) const;
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[[nodiscard]] constexpr auto const& socket_address() const noexcept
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{
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return socket_address_;
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}
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[[nodiscard]] constexpr auto const& address() const noexcept
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{
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return socket_address_.address();
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}
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[[nodiscard]] constexpr auto port() const noexcept
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{
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return socket_address_.port();
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}
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[[nodiscard]] std::string display_name() const
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{
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return socket_address_.display_name();
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}
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[[nodiscard]] constexpr auto is_utp() const noexcept
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{
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return type_ == Type::UTP;
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}
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[[nodiscard]] constexpr auto is_tcp() const noexcept
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{
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return type_ == Type::TCP;
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}
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[[nodiscard]] constexpr auto is_valid() const noexcept
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{
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#ifdef WITH_UTP
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return is_tcp() || is_utp();
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#else
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return is_tcp();
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#endif
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}
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[[nodiscard]] constexpr size_t guess_packet_overhead(size_t n_bytes) const noexcept
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{
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if (is_tcp())
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{
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// https://web.archive.org/web/20140912230020/http://sd.wareonearth.com:80/~phil/net/overhead/
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// TCP over Ethernet:
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// Assuming no header compression (e.g. not PPP)
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// Add 20 IPv4 header or 40 IPv6 header (no options)
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// Add 20 TCP header
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// Add 12 bytes optional TCP timestamps
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// Max TCP Payload data rates over ethernet are thus:
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// (1500-40)/ (38+1500) = 94.9285 % IPv4, minimal headers
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// (1500-52)/ (38+1500) = 94.1482 % IPv4, TCP timestamps
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// (1500-52)/ (42+1500) = 93.9040 % 802.1q, IPv4, TCP timestamps
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// (1500-60)/ (38+1500) = 93.6281 % IPv6, minimal headers
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// (1500-72)/ (38+1500) = 92.8479 % IPv6, TCP timestamps
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// (1500-72)/ (42+1500) = 92.6070 % 802.1q, IPv6, TCP timestamps
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// So, let's guess around 7% overhead
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return n_bytes / 14U;
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}
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// We only guess for TCP; uTP tracks its overhead via UTP_ON_OVERHEAD_STATISTICS
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return {};
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}
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union
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{
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tr_socket_t tcp;
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struct UTPSocket* utp;
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} handle = {};
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[[nodiscard]] static bool limit_reached(tr_session const* session) noexcept;
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private:
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enum class Type
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{
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None,
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TCP,
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UTP
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};
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tr_socket_address socket_address_;
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enum Type type_ = Type::None;
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static inline std::atomic<size_t> n_open_sockets_ = {};
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};
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tr_peer_socket tr_netOpenPeerSocket(tr_session* session, tr_socket_address const& socket_address, bool client_is_seed);
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