296 lines
9.0 KiB
C++
296 lines
9.0 KiB
C++
/*
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* Copyright 2004 The WebRTC Project Authors. All rights reserved.
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*
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* Use of this source code is governed by a BSD-style license
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* that can be found in the LICENSE file in the root of the source
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* tree. An additional intellectual property rights grant can be found
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* in the file PATENTS. All contributing project authors may
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* be found in the AUTHORS file in the root of the source tree.
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*/
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#ifndef P2P_BASE_PSEUDO_TCP_H_
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#define P2P_BASE_PSEUDO_TCP_H_
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#include <stddef.h>
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#include <stdint.h>
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#include <list>
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#include <memory>
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#include "rtc_base/synchronization/mutex.h"
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#include "rtc_base/system/rtc_export.h"
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namespace cricket {
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//////////////////////////////////////////////////////////////////////
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// IPseudoTcpNotify
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//////////////////////////////////////////////////////////////////////
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class PseudoTcp;
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class IPseudoTcpNotify {
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public:
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// Notification of tcp events
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virtual void OnTcpOpen(PseudoTcp* tcp) = 0;
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virtual void OnTcpReadable(PseudoTcp* tcp) = 0;
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virtual void OnTcpWriteable(PseudoTcp* tcp) = 0;
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virtual void OnTcpClosed(PseudoTcp* tcp, uint32_t error) = 0;
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// Write the packet onto the network
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enum WriteResult { WR_SUCCESS, WR_TOO_LARGE, WR_FAIL };
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virtual WriteResult TcpWritePacket(PseudoTcp* tcp,
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const char* buffer,
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size_t len) = 0;
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protected:
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virtual ~IPseudoTcpNotify() {}
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};
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//////////////////////////////////////////////////////////////////////
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// PseudoTcp
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//////////////////////////////////////////////////////////////////////
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class RTC_EXPORT PseudoTcp {
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public:
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static uint32_t Now();
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PseudoTcp(IPseudoTcpNotify* notify, uint32_t conv);
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virtual ~PseudoTcp();
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int Connect();
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int Recv(char* buffer, size_t len);
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int Send(const char* buffer, size_t len);
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void Close(bool force);
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int GetError();
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enum TcpState {
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TCP_LISTEN,
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TCP_SYN_SENT,
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TCP_SYN_RECEIVED,
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TCP_ESTABLISHED,
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TCP_CLOSED
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};
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TcpState State() const { return m_state; }
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// Call this when the PMTU changes.
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void NotifyMTU(uint16_t mtu);
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// Call this based on timeout value returned from GetNextClock.
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// It's ok to call this too frequently.
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void NotifyClock(uint32_t now);
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// Call this whenever a packet arrives.
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// Returns true if the packet was processed successfully.
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bool NotifyPacket(const char* buffer, size_t len);
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// Call this to determine the next time NotifyClock should be called.
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// Returns false if the socket is ready to be destroyed.
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bool GetNextClock(uint32_t now, long& timeout);
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// Call these to get/set option values to tailor this PseudoTcp
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// instance's behaviour for the kind of data it will carry.
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// If an unrecognized option is set or got, an assertion will fire.
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//
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// Setting options for OPT_RCVBUF or OPT_SNDBUF after Connect() is called
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// will result in an assertion.
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enum Option {
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OPT_NODELAY, // Whether to enable Nagle's algorithm (0 == off)
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OPT_ACKDELAY, // The Delayed ACK timeout (0 == off).
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OPT_RCVBUF, // Set the receive buffer size, in bytes.
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OPT_SNDBUF, // Set the send buffer size, in bytes.
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};
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void GetOption(Option opt, int* value);
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void SetOption(Option opt, int value);
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// Returns current congestion window in bytes.
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uint32_t GetCongestionWindow() const;
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// Returns amount of data in bytes that has been sent, but haven't
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// been acknowledged.
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uint32_t GetBytesInFlight() const;
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// Returns number of bytes that were written in buffer and haven't
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// been sent.
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uint32_t GetBytesBufferedNotSent() const;
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// Returns current round-trip time estimate in milliseconds.
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uint32_t GetRoundTripTimeEstimateMs() const;
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protected:
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enum SendFlags { sfNone, sfDelayedAck, sfImmediateAck };
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struct Segment {
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uint32_t conv, seq, ack;
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uint8_t flags;
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uint16_t wnd;
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const char* data;
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uint32_t len;
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uint32_t tsval, tsecr;
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};
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struct SSegment {
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SSegment(uint32_t s, uint32_t l, bool c)
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: seq(s), len(l), /*tstamp(0),*/ xmit(0), bCtrl(c) {}
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uint32_t seq, len;
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// uint32_t tstamp;
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uint8_t xmit;
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bool bCtrl;
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};
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typedef std::list<SSegment> SList;
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struct RSegment {
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uint32_t seq, len;
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};
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uint32_t queue(const char* data, uint32_t len, bool bCtrl);
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// Creates a packet and submits it to the network. This method can either
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// send payload or just an ACK packet.
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//
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// `seq` is the sequence number of this packet.
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// `flags` is the flags for sending this packet.
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// `offset` is the offset to read from `m_sbuf`.
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// `len` is the number of bytes to read from `m_sbuf` as payload. If this
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// value is 0 then this is an ACK packet, otherwise this packet has payload.
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IPseudoTcpNotify::WriteResult packet(uint32_t seq,
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uint8_t flags,
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uint32_t offset,
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uint32_t len);
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bool parse(const uint8_t* buffer, uint32_t size);
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void attemptSend(SendFlags sflags = sfNone);
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void closedown(uint32_t err = 0);
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bool clock_check(uint32_t now, long& nTimeout);
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bool process(Segment& seg);
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bool transmit(const SList::iterator& seg, uint32_t now);
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void adjustMTU();
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protected:
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// This method is used in test only to query receive buffer state.
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bool isReceiveBufferFull() const;
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// This method is only used in tests, to disable window scaling
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// support for testing backward compatibility.
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void disableWindowScale();
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private:
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// Queue the connect message with TCP options.
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void queueConnectMessage();
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// Parse TCP options in the header.
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void parseOptions(const char* data, uint32_t len);
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// Apply a TCP option that has been read from the header.
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void applyOption(char kind, const char* data, uint32_t len);
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// Apply window scale option.
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void applyWindowScaleOption(uint8_t scale_factor);
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// Resize the send buffer with `new_size` in bytes.
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void resizeSendBuffer(uint32_t new_size);
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// Resize the receive buffer with `new_size` in bytes. This call adjusts
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// window scale factor `m_swnd_scale` accordingly.
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void resizeReceiveBuffer(uint32_t new_size);
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class LockedFifoBuffer final {
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public:
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explicit LockedFifoBuffer(size_t size);
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~LockedFifoBuffer();
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size_t GetBuffered() const;
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bool SetCapacity(size_t size);
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bool ReadOffset(void* buffer,
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size_t bytes,
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size_t offset,
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size_t* bytes_read);
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bool WriteOffset(const void* buffer,
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size_t bytes,
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size_t offset,
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size_t* bytes_written);
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bool Read(void* buffer, size_t bytes, size_t* bytes_read);
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bool Write(const void* buffer, size_t bytes, size_t* bytes_written);
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void ConsumeReadData(size_t size);
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void ConsumeWriteBuffer(size_t size);
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bool GetWriteRemaining(size_t* size) const;
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private:
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bool ReadOffsetLocked(void* buffer,
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size_t bytes,
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size_t offset,
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size_t* bytes_read)
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RTC_EXCLUSIVE_LOCKS_REQUIRED(mutex_);
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bool WriteOffsetLocked(const void* buffer,
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size_t bytes,
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size_t offset,
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size_t* bytes_written)
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RTC_EXCLUSIVE_LOCKS_REQUIRED(mutex_);
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// the allocated buffer
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std::unique_ptr<char[]> buffer_ RTC_GUARDED_BY(mutex_);
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// size of the allocated buffer
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size_t buffer_length_ RTC_GUARDED_BY(mutex_);
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// amount of readable data in the buffer
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size_t data_length_ RTC_GUARDED_BY(mutex_);
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// offset to the readable data
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size_t read_position_ RTC_GUARDED_BY(mutex_);
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mutable webrtc::Mutex mutex_;
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};
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IPseudoTcpNotify* m_notify;
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enum Shutdown { SD_NONE, SD_GRACEFUL, SD_FORCEFUL } m_shutdown;
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int m_error;
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// TCB data
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TcpState m_state;
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uint32_t m_conv;
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bool m_bReadEnable, m_bWriteEnable, m_bOutgoing;
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uint32_t m_lasttraffic;
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// Incoming data
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typedef std::list<RSegment> RList;
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RList m_rlist;
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uint32_t m_rbuf_len, m_rcv_nxt, m_rcv_wnd, m_lastrecv;
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uint8_t m_rwnd_scale; // Window scale factor.
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LockedFifoBuffer m_rbuf;
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// Outgoing data
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SList m_slist;
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uint32_t m_sbuf_len, m_snd_nxt, m_snd_wnd, m_lastsend, m_snd_una;
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uint8_t m_swnd_scale; // Window scale factor.
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LockedFifoBuffer m_sbuf;
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// Maximum segment size, estimated protocol level, largest segment sent
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uint32_t m_mss, m_msslevel, m_largest, m_mtu_advise;
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// Retransmit timer
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uint32_t m_rto_base;
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// Timestamp tracking
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uint32_t m_ts_recent, m_ts_lastack;
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// Round-trip calculation
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uint32_t m_rx_rttvar, m_rx_srtt, m_rx_rto;
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// Congestion avoidance, Fast retransmit/recovery, Delayed ACKs
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uint32_t m_ssthresh, m_cwnd;
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uint8_t m_dup_acks;
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uint32_t m_recover;
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uint32_t m_t_ack;
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// Configuration options
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bool m_use_nagling;
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uint32_t m_ack_delay;
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// This is used by unit tests to test backward compatibility of
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// PseudoTcp implementations that don't support window scaling.
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bool m_support_wnd_scale;
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};
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} // namespace cricket
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#endif // P2P_BASE_PSEUDO_TCP_H_
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