add serial port(COM) listener and handler

handler/com/handler.go

@@ -0,0 +1,159 @@
+package com
+
+import (
+	"context"
+	"errors"
+	"net"
+	"strings"
+	"time"
+
+	"github.com/go-gost/core/chain"
+	"github.com/go-gost/core/handler"
+	"github.com/go-gost/core/logger"
+	md "github.com/go-gost/core/metadata"
+	xnet "github.com/go-gost/x/internal/net"
+	"github.com/go-gost/x/registry"
+	goserial "github.com/tarm/serial"
+)
+
+func init() {
+	registry.HandlerRegistry().Register("com", NewHandler)
+}
+
+type comHandler struct {
+	hop     chain.Hop
+	router  *chain.Router
+	md      metadata
+	options handler.Options
+}
+
+func NewHandler(opts ...handler.Option) handler.Handler {
+	options := handler.Options{}
+	for _, opt := range opts {
+		opt(&options)
+	}
+
+	return &comHandler{
+		options: options,
+	}
+}
+
+func (h *comHandler) Init(md md.Metadata) (err error) {
+	if err = h.parseMetadata(md); err != nil {
+		return
+	}
+
+	h.router = h.options.Router
+	if h.router == nil {
+		h.router = chain.NewRouter(chain.LoggerRouterOption(h.options.Logger))
+	}
+
+	return
+}
+
+// Forward implements handler.Forwarder.
+func (h *comHandler) Forward(hop chain.Hop) {
+	h.hop = hop
+}
+
+func (h *comHandler) Handle(ctx context.Context, conn net.Conn, opts ...handler.HandleOption) error {
+	defer conn.Close()
+
+	log := h.options.Logger
+
+	start := time.Now()
+	log = log.WithFields(map[string]any{
+		"remote": conn.RemoteAddr().String(),
+		"local":  conn.LocalAddr().String(),
+	})
+
+	log.Infof("%s <> %s", conn.RemoteAddr(), conn.LocalAddr())
+	defer func() {
+		log.WithFields(map[string]any{
+			"duration": time.Since(start),
+		}).Infof("%s >< %s", conn.RemoteAddr(), conn.LocalAddr())
+	}()
+
+	var target *chain.Node
+	if h.hop != nil {
+		target = h.hop.Select(ctx)
+	}
+
+	if target == nil {
+		err := errors.New("target not available")
+		log.Error(err)
+		return err
+	}
+
+	log = log.WithFields(map[string]any{
+		"node": target.Name,
+		"dst":  target.Addr,
+	})
+
+	log.Debugf("%s >> %s", conn.RemoteAddr(), target.Addr)
+
+	// serial port
+	if _, _, err := net.SplitHostPort(target.Addr); err != nil {
+		return h.forwardCom(ctx, conn, target, log)
+	}
+
+	cc, err := h.router.Dial(ctx, "tcp", target.Addr)
+	if err != nil {
+		log.Error(err)
+		if marker := target.Marker(); marker != nil {
+			marker.Mark()
+		}
+		return err
+	}
+	defer cc.Close()
+	if marker := target.Marker(); marker != nil {
+		marker.Reset()
+	}
+
+	t := time.Now()
+	log.Infof("%s <-> %s", conn.RemoteAddr(), target.Addr)
+	xnet.Transport(conn, cc)
+	log.WithFields(map[string]any{
+		"duration": time.Since(t),
+	}).Infof("%s >-< %s", conn.RemoteAddr(), target.Addr)
+
+	return nil
+}
+
+func (h *comHandler) forwardCom(ctx context.Context, conn net.Conn, target *chain.Node, log logger.Logger) error {
+	port, err := goserial.OpenPort(&goserial.Config{
+		Name:        target.Addr,
+		Baud:        h.md.baudRate,
+		Parity:      parseParity(h.md.parity),
+		ReadTimeout: h.md.timeout,
+	})
+	if err != nil {
+		return err
+	}
+
+	defer port.Close()
+
+	t := time.Now()
+	log.Infof("%s <-> %s", conn.RemoteAddr(), target.Addr)
+	xnet.Transport(conn, port)
+	log.WithFields(map[string]any{
+		"duration": time.Since(t),
+	}).Infof("%s >-< %s", conn.RemoteAddr(), target.Addr)
+
+	return nil
+}
+
+func parseParity(s string) goserial.Parity {
+	switch strings.ToLower(s) {
+	case "o", "odd":
+		return goserial.ParityOdd
+	case "e", "even":
+		return goserial.ParityEven
+	case "m", "mark":
+		return goserial.ParityMark
+	case "s", "space":
+		return goserial.ParitySpace
+	default:
+		return goserial.ParityNone
+	}
+}

handler/com/metadata.go

@@ -0,0 +1,32 @@
+package com
+
+import (
+	"time"
+
+	mdata "github.com/go-gost/core/metadata"
+	mdutil "github.com/go-gost/core/metadata/util"
+)
+
+const (
+	defaultBaudRate = 9600
+	defaultParity   = "odd"
+)
+
+type metadata struct {
+	baudRate int
+	parity   string
+	timeout  time.Duration
+}
+
+func (h *comHandler) parseMetadata(md mdata.Metadata) (err error) {
+	h.md.baudRate = mdutil.GetInt(md, "baud", "com.baud", "handler.com.baud")
+	if h.md.baudRate <= 0 {
+		h.md.baudRate = defaultBaudRate
+	}
+	h.md.parity = mdutil.GetString(md, "parity", "com.parity", "handler.com.parity")
+	if h.md.parity == "" {
+		h.md.parity = defaultParity
+	}
+	h.md.timeout = mdutil.GetDuration(md, "timeout", "com.timeout", "handler.com.timeout")
+	return
+}