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/*
* Copyright (c) 2021 The WebRTC project authors. All Rights Reserved.
*
* Use of this source code is governed by a BSD-style license
* that can be found in the LICENSE file in the root of the source
* tree. An additional intellectual property rights grant can be found
* in the file PATENTS. All contributing project authors may
* be found in the AUTHORS file in the root of the source tree.
*/
#ifndef NET_DCSCTP_SOCKET_DCSCTP_SOCKET_H_
#define NET_DCSCTP_SOCKET_DCSCTP_SOCKET_H_
#include <cstdint>
#include <memory>
#include <string>
#include <utility>
#include "absl/strings/string_view.h"
#include "api/array_view.h"
#include "net/dcsctp/packet/chunk/abort_chunk.h"
#include "net/dcsctp/packet/chunk/chunk.h"
#include "net/dcsctp/packet/chunk/cookie_ack_chunk.h"
#include "net/dcsctp/packet/chunk/cookie_echo_chunk.h"
#include "net/dcsctp/packet/chunk/data_chunk.h"
#include "net/dcsctp/packet/chunk/data_common.h"
#include "net/dcsctp/packet/chunk/error_chunk.h"
#include "net/dcsctp/packet/chunk/forward_tsn_chunk.h"
#include "net/dcsctp/packet/chunk/forward_tsn_common.h"
#include "net/dcsctp/packet/chunk/heartbeat_ack_chunk.h"
#include "net/dcsctp/packet/chunk/heartbeat_request_chunk.h"
#include "net/dcsctp/packet/chunk/idata_chunk.h"
#include "net/dcsctp/packet/chunk/iforward_tsn_chunk.h"
#include "net/dcsctp/packet/chunk/init_ack_chunk.h"
#include "net/dcsctp/packet/chunk/init_chunk.h"
#include "net/dcsctp/packet/chunk/reconfig_chunk.h"
#include "net/dcsctp/packet/chunk/sack_chunk.h"
#include "net/dcsctp/packet/chunk/shutdown_ack_chunk.h"
#include "net/dcsctp/packet/chunk/shutdown_chunk.h"
#include "net/dcsctp/packet/chunk/shutdown_complete_chunk.h"
#include "net/dcsctp/packet/data.h"
#include "net/dcsctp/packet/sctp_packet.h"
#include "net/dcsctp/public/dcsctp_message.h"
#include "net/dcsctp/public/dcsctp_options.h"
#include "net/dcsctp/public/dcsctp_socket.h"
#include "net/dcsctp/public/packet_observer.h"
#include "net/dcsctp/rx/data_tracker.h"
#include "net/dcsctp/rx/reassembly_queue.h"
#include "net/dcsctp/socket/callback_deferrer.h"
#include "net/dcsctp/socket/state_cookie.h"
#include "net/dcsctp/socket/transmission_control_block.h"
#include "net/dcsctp/timer/timer.h"
#include "net/dcsctp/tx/retransmission_error_counter.h"
#include "net/dcsctp/tx/retransmission_queue.h"
#include "net/dcsctp/tx/retransmission_timeout.h"
#include "net/dcsctp/tx/rr_send_queue.h"
namespace dcsctp {
// DcSctpSocket represents a single SCTP socket, to be used over DTLS.
//
// Every dcSCTP is completely isolated from any other socket.
//
// This class manages all packet and chunk dispatching and mainly handles the
// connection sequences (connect, close, shutdown, etc) as well as managing
// the Transmission Control Block (tcb).
//
// This class is thread-compatible.
class DcSctpSocket : public DcSctpSocketInterface {
public:
// Instantiates a DcSctpSocket, which interacts with the world through the
// `callbacks` interface and is configured using `options`.
//
// For debugging, `log_prefix` will prefix all debug logs, and a
// `packet_observer` can be attached to e.g. dump sent and received packets.
DcSctpSocket(absl::string_view log_prefix,
DcSctpSocketCallbacks& callbacks,
std::unique_ptr<PacketObserver> packet_observer,
const DcSctpOptions& options);
DcSctpSocket(const DcSctpSocket&) = delete;
DcSctpSocket& operator=(const DcSctpSocket&) = delete;
// Implementation of `DcSctpSocketInterface`.
void ReceivePacket(rtc::ArrayView<const uint8_t> data) override;
void HandleTimeout(TimeoutID timeout_id) override;
void Connect() override;
void Shutdown() override;
void Close() override;
SendStatus Send(DcSctpMessage message,
const SendOptions& send_options) override;
ResetStreamsStatus ResetStreams(
rtc::ArrayView<const StreamID> outgoing_streams) override;
SocketState state() const override;
const DcSctpOptions& options() const override { return options_; }
void SetMaxMessageSize(size_t max_message_size) override;
size_t buffered_amount(StreamID stream_id) const override;
size_t buffered_amount_low_threshold(StreamID stream_id) const override;
void SetBufferedAmountLowThreshold(StreamID stream_id, size_t bytes) override;
// Returns this socket's verification tag, or zero if not yet connected.
VerificationTag verification_tag() const {
return tcb_ != nullptr ? tcb_->my_verification_tag() : VerificationTag(0);
}
private:
// Parameter proposals valid during the connect phase.
struct ConnectParameters {
TSN initial_tsn = TSN(0);
VerificationTag verification_tag = VerificationTag(0);
};
// Detailed state (separate from SocketState, which is the public state).
enum class State {
kClosed,
kCookieWait,
// TCB valid in these:
kCookieEchoed,
kEstablished,
kShutdownPending,
kShutdownSent,
kShutdownReceived,
kShutdownAckSent,
};
// Returns the log prefix used for debug logging.
std::string log_prefix() const;
bool IsConsistent() const;
static constexpr absl::string_view ToString(DcSctpSocket::State state);
// Changes the socket state, given a `reason` (for debugging/logging).
void SetState(State state, absl::string_view reason);
// Fills in `connect_params` with random verification tag and initial TSN.
void MakeConnectionParameters();
// Closes the association. Note that the TCB will not be valid past this call.
void InternalClose(ErrorKind error, absl::string_view message);
// Closes the association, because of too many retransmission errors.
void CloseConnectionBecauseOfTooManyTransmissionErrors();
// Timer expiration handlers
absl::optional<DurationMs> OnInitTimerExpiry();
absl::optional<DurationMs> OnCookieTimerExpiry();
absl::optional<DurationMs> OnShutdownTimerExpiry();
// Builds the packet from `builder` and sends it (through callbacks).
void SendPacket(SctpPacket::Builder& builder);
// Sends SHUTDOWN or SHUTDOWN-ACK if the socket is shutting down and if all
// outstanding data has been acknowledged.
void MaybeSendShutdownOrAck();
// If the socket is shutting down, responds SHUTDOWN to any incoming DATA.
void MaybeSendShutdownOnPacketReceived(const SctpPacket& packet);
// Sends a INIT chunk.
void SendInit();
// Sends a SHUTDOWN chunk.
void SendShutdown();
// Sends a SHUTDOWN-ACK chunk.
void SendShutdownAck();
// Validates the SCTP packet, as a whole - not the validity of individual
// chunks within it, as that's done in the different chunk handlers.
bool ValidatePacket(const SctpPacket& packet);
// Parses `payload`, which is a serialized packet that is just going to be
// sent and prints all chunks.
void DebugPrintOutgoing(rtc::ArrayView<const uint8_t> payload);
// Called whenever there may be reassembled messages, and delivers those.
void DeliverReassembledMessages();
// Returns true if there is a TCB, and false otherwise (and reports an error).
bool ValidateHasTCB();
// Returns true if the parsing of a chunk of type `T` succeeded. If it didn't,
// it reports an error and returns false.
template <class T>
bool ValidateParseSuccess(const absl::optional<T>& c) {
if (c.has_value()) {
return true;
}
ReportFailedToParseChunk(T::kType);
return false;
}
// Reports failing to have parsed a chunk with the provided `chunk_type`.
void ReportFailedToParseChunk(int chunk_type);
// Called when unknown chunks are received. May report an error.
bool HandleUnrecognizedChunk(const SctpPacket::ChunkDescriptor& descriptor);
// Will dispatch more specific chunk handlers.
bool Dispatch(const CommonHeader& header,
const SctpPacket::ChunkDescriptor& descriptor);
// Handles incoming DATA chunks.
void HandleData(const CommonHeader& header,
const SctpPacket::ChunkDescriptor& descriptor);
// Handles incoming I-DATA chunks.
void HandleIData(const CommonHeader& header,
const SctpPacket::ChunkDescriptor& descriptor);
// Common handler for DATA and I-DATA chunks.
void HandleDataCommon(AnyDataChunk& chunk);
// Handles incoming INIT chunks.
void HandleInit(const CommonHeader& header,
const SctpPacket::ChunkDescriptor& descriptor);
// Handles incoming INIT-ACK chunks.
void HandleInitAck(const CommonHeader& header,
const SctpPacket::ChunkDescriptor& descriptor);
// Handles incoming SACK chunks.
void HandleSack(const CommonHeader& header,
const SctpPacket::ChunkDescriptor& descriptor);
// Handles incoming HEARTBEAT chunks.
void HandleHeartbeatRequest(const CommonHeader& header,
const SctpPacket::ChunkDescriptor& descriptor);
// Handles incoming HEARTBEAT-ACK chunks.
void HandleHeartbeatAck(const CommonHeader& header,
const SctpPacket::ChunkDescriptor& descriptor);
// Handles incoming ABORT chunks.
void HandleAbort(const CommonHeader& header,
const SctpPacket::ChunkDescriptor& descriptor);
// Handles incoming ERROR chunks.
void HandleError(const CommonHeader& header,
const SctpPacket::ChunkDescriptor& descriptor);
// Handles incoming COOKIE-ECHO chunks.
void HandleCookieEcho(const CommonHeader& header,
const SctpPacket::ChunkDescriptor& descriptor);
// Handles receiving COOKIE-ECHO when there already is a TCB. The return value
// indicates if the processing should continue.
bool HandleCookieEchoWithTCB(const CommonHeader& header,
const StateCookie& cookie);
// Handles incoming COOKIE-ACK chunks.
void HandleCookieAck(const CommonHeader& header,
const SctpPacket::ChunkDescriptor& descriptor);
// Handles incoming SHUTDOWN chunks.
void HandleShutdown(const CommonHeader& header,
const SctpPacket::ChunkDescriptor& descriptor);
// Handles incoming SHUTDOWN-ACK chunks.
void HandleShutdownAck(const CommonHeader& header,
const SctpPacket::ChunkDescriptor& descriptor);
// Handles incoming FORWARD-TSN chunks.
void HandleForwardTsn(const CommonHeader& header,
const SctpPacket::ChunkDescriptor& descriptor);
// Handles incoming I-FORWARD-TSN chunks.
void HandleIForwardTsn(const CommonHeader& header,
const SctpPacket::ChunkDescriptor& descriptor);
// Handles incoming RE-CONFIG chunks.
void HandleReconfig(const CommonHeader& header,
const SctpPacket::ChunkDescriptor& descriptor);
// Common handled for FORWARD-TSN/I-FORWARD-TSN.
void HandleForwardTsnCommon(const AnyForwardTsnChunk& chunk);
// Handles incoming SHUTDOWN-COMPLETE chunks
void HandleShutdownComplete(const CommonHeader& header,
const SctpPacket::ChunkDescriptor& descriptor);
const std::string log_prefix_;
const std::unique_ptr<PacketObserver> packet_observer_;
DcSctpOptions options_;
// Enqueues callbacks and dispatches them just before returning to the caller.
CallbackDeferrer callbacks_;
TimerManager timer_manager_;
const std::unique_ptr<Timer> t1_init_;
const std::unique_ptr<Timer> t1_cookie_;
const std::unique_ptr<Timer> t2_shutdown_;
// The actual SendQueue implementation. As data can be sent on a socket before
// the connection is established, this component is not in the TCB.
RRSendQueue send_queue_;
// Contains verification tag and initial TSN between having sent the INIT
// until the connection is established (there is no TCB at this point).
ConnectParameters connect_params_;
// The socket state.
State state_ = State::kClosed;
// If the connection is established, contains a transmission control block.
std::unique_ptr<TransmissionControlBlock> tcb_;
};
} // namespace dcsctp
#endif // NET_DCSCTP_SOCKET_DCSCTP_SOCKET_H_