diff options
| -rw-r--r-- | .gitignore | 3 | ||||
| -rw-r--r-- | LICENSE | 674 | ||||
| -rw-r--r-- | client.go | 262 | ||||
| -rw-r--r-- | client_publish.go | 40 | ||||
| -rw-r--r-- | go.mod | 5 | ||||
| -rw-r--r-- | go.sum | 2 | ||||
| -rw-r--r-- | protocol/client_mode.go | 103 | ||||
| -rw-r--r-- | protocol/client_protocol.go | 186 | ||||
| -rw-r--r-- | protocol/client_recv.go | 66 |
9 files changed, 1341 insertions, 0 deletions
diff --git a/.gitignore b/.gitignore new file mode 100644 index 0000000..56fad2d --- /dev/null +++ b/.gitignore @@ -0,0 +1,3 @@ +.idea/ +.code/ +.vscode/ @@ -0,0 +1,674 @@ + GNU GENERAL PUBLIC LICENSE + Version 3, 29 June 2007 + + Copyright (C) 2007 Free Software Foundation, Inc. <https://fsf.org/> + Everyone is permitted to copy and distribute verbatim copies + of this license document, but changing it is not allowed. + + Preamble + + The GNU General Public License is a free, copyleft license for +software and other kinds of works. + + The licenses for most software and other practical works are designed +to take away your freedom to share and change the works. By contrast, +the GNU General Public License is intended to guarantee your freedom to +share and change all versions of a program--to make sure it remains free +software for all its users. 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If not, see <https://www.gnu.org/licenses/>. + +Also add information on how to contact you by electronic and paper mail. + + If the program does terminal interaction, make it output a short +notice like this when it starts in an interactive mode: + + <program> Copyright (C) <year> <name of author> + This program comes with ABSOLUTELY NO WARRANTY; for details type `show w'. + This is free software, and you are welcome to redistribute it + under certain conditions; type `show c' for details. + +The hypothetical commands `show w' and `show c' should show the appropriate +parts of the General Public License. Of course, your program's commands +might be different; for a GUI interface, you would use an "about box". + + You should also get your employer (if you work as a programmer) or school, +if any, to sign a "copyright disclaimer" for the program, if necessary. +For more information on this, and how to apply and follow the GNU GPL, see +<https://www.gnu.org/licenses/>. + + The GNU General Public License does not permit incorporating your program +into proprietary programs. If your program is a subroutine library, you +may consider it more useful to permit linking proprietary applications with +the library. If this is what you want to do, use the GNU Lesser General +Public License instead of this License. But first, please read +<https://www.gnu.org/licenses/why-not-lgpl.html>. diff --git a/client.go b/client.go new file mode 100644 index 0000000..b6c8288 --- /dev/null +++ b/client.go @@ -0,0 +1,262 @@ +package psmb + +import ( + "bufio" + "fmt" + "github.com/go-logr/logr" + "github.com/hit-mc/psmb-go/protocol" + "io" + "math" + "net" + "strconv" + "sync" + "sync/atomic" + "time" +) + +// Client provides auto reconnect and buffered abstraction for protocol.Client +type Client struct { + conn *net.TCPConn + impl protocol.Client // owned by keepSession + mode protocol.ClientMode + host string + port uint16 + txQueue chan OutboundMessage + incompleteTx []OutboundMessage // messages already taken out from txQueue but has not been sent + closed atomic.Bool // closed is set only if Close is called. + retryIntervalConnect time.Duration + log logr.Logger + errorConsumer func(err error) // thread-safe + heartBeatInterval time.Duration // zero means no heartbeat + wgClose sync.WaitGroup +} + +func nopErrConsumer(error) {} + +func NewClient( + host string, port uint16, + mode protocol.ClientMode, + errorConsumer func(err error), + heartBeatInterval time.Duration, + connectRetryInterval time.Duration, + logger logr.Logger, +) *Client { + if errorConsumer == nil { + errorConsumer = nopErrConsumer + } else { + realErrorConsumer := errorConsumer + mu := &sync.Mutex{} + errorConsumer = func(err error) { + mu.Lock() + defer mu.Unlock() + if err == nil { + return + } + realErrorConsumer(err) + } + } + if heartBeatInterval < time.Millisecond*10 && heartBeatInterval != 0 { + panic(fmt.Errorf("heartbeat interval is too short")) + } + c := &Client{ + impl: protocol.Client{}, + mode: mode, + host: host, + port: port, + txQueue: make(chan OutboundMessage, 128), + incompleteTx: make([]OutboundMessage, 0, 16), + retryIntervalConnect: connectRetryInterval, + log: logger, + errorConsumer: errorConsumer, + heartBeatInterval: heartBeatInterval, + } + go c.keepImpl() + return c +} + +// keepImpl ensures the impl is always alive and send/receive objects to/from the remote server. +func (c *Client) keepImpl() { + for !c.closed.Load() { + c.keepSession() + } +} + +// responder stores data that should be sent as a response. +type responder struct { + nil chan struct{} // nil is true if there is a NIL command to be sent. + disconnect atomic.Bool // disconnect is true if the remote peer has sent BYE or rx/tx has disconnected. +} + +func (c *Client) send(re *responder) error { + sendHeartBeat := true + interval := c.heartBeatInterval + if interval == 0 { + interval = time.Duration(math.MaxInt64) + sendHeartBeat = false + } + heartBeater := time.NewTicker(interval) + defer heartBeater.Stop() + for { + closed := c.closed.Load() + if closed { + c.log.Info("client closed, break send loop") + return nil + } + disconnected := re.disconnect.Load() + if disconnected { + c.log.Info("another direction disconnected, break send loop") + return nil + } + select { + case msg := <-c.txQueue: + if c.mode.Type() != protocol.ModePublish { + c.log.Error(nil, "cannot publish in non-publish mode, the message is ignored") + continue + } + err := c.impl.Publish(msg.getContent()) + if err != nil { + return fmt.Errorf("publish: %w", err) + } + case <-re.nil: + // respond with NIL + c.log.V(1).Info("sending NIL") + err := c.impl.Nil() + if err != nil { + return fmt.Errorf("send nil: %w", err) + } + case <-heartBeater.C: + if !sendHeartBeat { + continue + } + err := c.impl.Nop() + if err != nil { + return fmt.Errorf("send nop: %w", err) + } + } + } +} + +func (c *Client) receive(re *responder) error { + for { + closed := c.closed.Load() + if closed { + c.log.Info("client closed, break receive loop") + return nil + } + disconnected := re.disconnect.Load() + if disconnected { + c.log.Info("another direction disconnected, break receive loop") + return nil + } + msg, err := c.impl.Receive() + if err != nil { + return err + } + msg.Consume(func(r io.Reader, length int64) { + if c.mode.Type() != protocol.ModeSubscribe { + c.log.Error(nil, "ignoring server data message in subscribe mode") + return + } + c.mode.Consume(r, length) + }) + cmd := msg.Command() + c.log.V(1).Info("received message", "command", cmd) + switch cmd { + case protocol.CmdMsg: + // ignore + case protocol.CmdNop: + select { + case re.nil <- struct{}{}: + default: + c.log.Error(nil, "nil tx channel is full, sender thread may get blocked, "+ + "or server is sending NOP too fast") + } + case protocol.CmdBye: + // we should stop this impl and reconnect + re.disconnect.Store(true) + case protocol.CmdNil: + // ignore + } + } +} + +func (c *Client) keepSession() { + c.log.Info("connecting") + closer, err := c.connect() + if err != nil { + c.errorConsumer(fmt.Errorf("failed to connect, waiting for reconnect: %w", err)) + time.Sleep(c.retryIntervalConnect) + return + } + defer closer() + c.log.V(1).Info("handshaking") + err = c.impl.Handshake() + if err != nil { + c.errorConsumer(fmt.Errorf("handshake: %w", err)) + return + } + c.log.V(1).Info("selecting mode") + err = c.impl.SelectMode(c.mode) + if err != nil { + c.errorConsumer(fmt.Errorf("select mode: %w", err)) + return + } + c.log.Info("session started") + // tx thread + rxTxSharedCtx := responder{ + nil: make(chan struct{}, 8), + } + if c.closed.Load() { + return + } + wg := &sync.WaitGroup{} + wg.Add(1) + c.wgClose.Add(1) + go func() { + defer wg.Done() + defer c.wgClose.Done() + err := c.send(&rxTxSharedCtx) + if err != nil { + c.errorConsumer(fmt.Errorf("sender: %w", err)) + } + c.log.Info("sender stopped") + }() + wg.Add(1) + c.wgClose.Add(1) + go func() { + defer wg.Done() + defer c.wgClose.Done() + err := c.receive(&rxTxSharedCtx) + if err != nil { + c.errorConsumer(fmt.Errorf("receiver: %w", err)) + } + c.log.Info("receiver stopped") + }() + wg.Wait() + c.log.Info("session stopped") +} + +// connect initiates the TCP connection to server and creates impl instance. +func (c *Client) connect() (closer func(), err error) { + addr, err := net.ResolveTCPAddr("tcp", c.host+":"+strconv.Itoa(int(c.port))) + if err != nil { + return nil, fmt.Errorf("resolve: %w", err) + } + conn, err := net.DialTCP("tcp", nil, addr) + if err != nil { + return nil, fmt.Errorf("dial TCP: %w", err) + } + c.impl = protocol.NewClient(bufio.NewWriter(conn), bufio.NewReader(conn)) + return func() { + _ = conn.Close() + }, nil +} + +func (c *Client) Close() error { + if c.closed.Load() { + return nil + } + c.closed.Store(true) + c.wgClose.Wait() + return nil +} diff --git a/client_publish.go b/client_publish.go new file mode 100644 index 0000000..f80f1ab --- /dev/null +++ b/client_publish.go @@ -0,0 +1,40 @@ +package psmb + +import ( + "bytes" + "fmt" + "github.com/hit-mc/psmb-go/protocol" + "io" +) + +// Publish a message. Panic if client mode is not Publisher. Block if send queue is full. +func (c *Client) Publish(msg []byte) error { + if c.mode.Type() != protocol.ModePublish { + panic(fmt.Errorf("invalid operation")) + } + c.txQueue <- bytesOutboundMessage{ + b: msg, + waitChan: make(chan error), + } + return nil +} + +type OutboundMessage interface { + // getContent return the content reader and length in bytes + getContent() (io.Reader, int64) + // Wait returns a channel which blocks until this message is successfully sent to the server. + Wait() <-chan error +} + +type bytesOutboundMessage struct { + b []byte + waitChan chan error +} + +func (b bytesOutboundMessage) getContent() (io.Reader, int64) { + return bytes.NewReader(b.b), int64(len(b.b)) +} + +func (b bytesOutboundMessage) Wait() <-chan error { + return b.waitChan +} @@ -0,0 +1,5 @@ +module github.com/hit-mc/psmb-go + +go 1.18 + +require github.com/go-logr/logr v1.4.1 @@ -0,0 +1,2 @@ +github.com/go-logr/logr v1.4.1 h1:pKouT5E8xu9zeFC39JXRDukb6JFQPXM5p5I91188VAQ= +github.com/go-logr/logr v1.4.1/go.mod h1:9T104GzyrTigFIr8wt5mBrctHMim0Nb2HLGrmQ40KvY= diff --git a/protocol/client_mode.go b/protocol/client_mode.go new file mode 100644 index 0000000..b9ca057 --- /dev/null +++ b/protocol/client_mode.go @@ -0,0 +1,103 @@ +package protocol + +import ( + "bufio" + "errors" + "fmt" + "io" +) + +type ModeType uint16 + +const ( + ModePublish ModeType = 1 + ModeSubscribe ModeType = 2 +) + +type ClientMode interface { + Type() ModeType + // Consume a message from remote peer. This method should panic if not supported. + Consume(reader io.Reader, length int64) + sendSelectionRequest(c *Client) error +} + +func Publish(topicID string) ClientMode { + return modePublish{ + topicID: topicID, + } +} + +type modePublish struct { + topicID string +} + +func (m modePublish) Consume(io.Reader, int64) { + // it's the user's responsibility to filter out unsuitable messages + panic(errors.New("remote peer should not send data message to publisher")) +} + +func (m modePublish) Type() ModeType { + return ModePublish +} + +func (m modePublish) sendSelectionRequest(c *Client) error { + if m.topicID == "" { + panic(fmt.Errorf("empty subscription topic ID")) + } + return c.writeFlush("PUB" + m.topicID + "\x00") +} + +func Subscribe(topicIDPattern string, messageConsumer func(reader io.Reader, length int64)) ClientMode { + return modeSubscribe{ + topicIDPattern: topicIDPattern, + messageConsumer: messageConsumer, + } +} + +type modeSubscribe struct { + topicIDPattern string + messageConsumer func(reader io.Reader, length int64) +} + +func (m modeSubscribe) Consume(reader io.Reader, length int64) { + m.messageConsumer(reader, length) +} + +func (m modeSubscribe) Type() ModeType { + return ModeSubscribe +} + +func (m modeSubscribe) sendSelectionRequest(c *Client) error { + return c.writeFlush("SUB\x00\x00\x00\x00" + m.topicIDPattern + "\x00") +} + +func readModeSelectionResponse(r *bufio.Reader) error { + msg, err := r.ReadString('\x00') + if err != nil { + return err + } + msg = msg[:len(msg)-1] + if msg == "OK" { + return nil + } + // failed or other protocol errors + if msg == "FAILED" { + msg2, err := r.ReadString('\x00') + if err != nil { + return err + } + msg += ": " + msg2[:len(msg2)-1] + } + return protocolError{ + phase: PhaseModeSelection, + message: msg, + } +} + +func (c *Client) SelectMode(mode ClientMode) error { + err := mode.sendSelectionRequest(c) + if err != nil { + return err + } + return readModeSelectionResponse(c.rx) +} diff --git a/protocol/client_protocol.go b/protocol/client_protocol.go new file mode 100644 index 0000000..3128527 --- /dev/null +++ b/protocol/client_protocol.go @@ -0,0 +1,186 @@ +package protocol + +import ( + "bufio" + "encoding/binary" + "errors" + "fmt" + "io" + "reflect" +) + +type Command string + +const ( + CmdMsg Command = "MSG" + CmdNop Command = "NOP" + CmdBye Command = "BYE" + CmdNil Command = "NIL" +) + +type ConnectionPhase uint16 + +func (c ConnectionPhase) String() string { + s, ok := phaseStrings[c] + if ok { + return s + } + return fmt.Sprintf("<Unknown ConnectionPhase %v>", int(c)) +} + +const ( + PhaseHandshake ConnectionPhase = 1 + PhaseModeSelection ConnectionPhase = 2 +) + +var phaseStrings = map[ConnectionPhase]string{ + PhaseHandshake: "Handshake", + PhaseModeSelection: "ModeSelection", +} + +type protocolError struct { + phase ConnectionPhase + message string +} + +func (p protocolError) Error() string { + return fmt.Sprintf("protocol error, phase=%v, server message=%v", p.phase, p.message) +} + +func NewClient(tx *bufio.Writer, rx *bufio.Reader) Client { + return Client{ + tx: tx, + rx: rx, + } +} + +type Client struct { + tx *bufio.Writer + rx *bufio.Reader +} + +func (c *Client) read(v interface{}) error { + return binary.Read(c.rx, binary.BigEndian, v) +} + +// write given data in write format. +// Note: this method DOES NOT flush the write buffer! +func (c *Client) write(v interface{}) error { + if v == nil { + panic(errors.New("writing nil")) + } + vv := reflect.ValueOf(v) + if vv.Kind() == reflect.String { + _, err := c.tx.Write([]byte(vv.String())) + return err + } + if vv.Kind() >= reflect.Int && vv.Kind() <= reflect.Uint64 { + return binary.Write(c.tx, binary.BigEndian, v) + } + panic(fmt.Errorf("unsupported type to write: %v, kind: %v", vv.Type(), vv.Kind())) +} + +func (c *Client) writeFlush(v interface{}) error { + err := c.write(v) + if err != nil { + return err + } + return c.flush() +} + +func (c *Client) flush() error { + return c.tx.Flush() +} + +const handshakeSequence = "PSMB" + +func (c *Client) Handshake() error { + err := c.write(handshakeSequence) + if err != nil { + return err + } + const ( + protocolVersion uint32 = 2 + protocolOptions uint32 = 0 + ) + err = c.write(protocolVersion) + if err != nil { + return err + } + err = c.write(protocolOptions) + if err != nil { + return err + } + err = c.flush() + if err != nil { + return err + } + msg, err := c.rx.ReadString('\x00') + if err != nil { + return err + } + msg = msg[:len(msg)-1] + if msg != "OK" { + return protocolError{ + phase: PhaseHandshake, + message: msg, + } + } + var serverOptions uint32 + err = c.read(&serverOptions) + if err != nil { + return err + } + if serverOptions != 0 { + return fmt.Errorf("invalid server options: %v", serverOptions) + } + return nil +} + +func (c *Client) Publish(msg io.Reader, n int64) error { + err := c.write(CmdMsg) + if err != nil { + return err + } + err = c.write(uint64(n)) + if err != nil { + return err + } + _, err = io.CopyN(c.tx, msg, n) + if err != nil { + return err + } + err = c.flush() + if err != nil { + return err + } + return err +} + +func (c *Client) PublishBytes(msg []byte) error { + err := c.write(CmdMsg) + if err != nil { + return err + } + err = c.write(uint64(len(msg))) + if err != nil { + return err + } + err = c.write(msg) + if err != nil { + return err + } + return c.flush() +} + +func (c *Client) Nop() error { + return c.writeFlush(CmdNop) +} + +func (c *Client) Bye() error { + return c.writeFlush(CmdBye) +} + +func (c *Client) Nil() error { + return c.writeFlush(CmdNil) +} diff --git a/protocol/client_recv.go b/protocol/client_recv.go new file mode 100644 index 0000000..eb406c2 --- /dev/null +++ b/protocol/client_recv.go @@ -0,0 +1,66 @@ +package protocol + +import ( + "bytes" + "fmt" + "io" +) + +func (c *Client) Receive() (Message, error) { + var cmd [3]byte + _, err := io.ReadFull(c.rx, cmd[:]) + if err != nil { + return nil, err + } + typ := Command(cmd[:]) + switch typ { + case CmdMsg: + var length uint64 + err = c.read(&length) + if err != nil { + return nil, err + } + data := make([]byte, length) + _, err = io.ReadFull(c.rx, data) + if err != nil { + return nil, err + } + return commandMsg{ + data: data, + }, nil + case CmdNop: + fallthrough + case CmdBye: + fallthrough + case CmdNil: + return trivialCommand(typ), nil + default: + return nil, fmt.Errorf("unknown command from server: %v", string(cmd[:])) + } +} + +type Message interface { + Command() Command + // Consume calls messageConsumer is this message contains a data message to the upper level. + Consume(messageConsumer func(reader io.Reader, length int64)) +} + +type trivialCommand Command + +func (t trivialCommand) Consume(func(reader io.Reader, length int64)) {} + +func (t trivialCommand) Command() Command { + return Command(t) +} + +type commandMsg struct { + data []byte +} + +func (c commandMsg) Consume(messageConsumer func(reader io.Reader, length int64)) { + messageConsumer(bytes.NewReader(c.data), int64(len(c.data))) +} + +func (c commandMsg) Command() Command { + return CmdMsg +} |