working commit

app/rproxy/forwarder.go

@@ -0,0 +1,124 @@
+package rproxy
+
+import (
+	"context"
+	"io"
+	"math/rand"
+	"net"
+	"strconv"
+	"sync"
+
+	"helmet/app/logger"
+)
+
+type Forwarder struct {
+	listen net.Listener       `json:"-"      yaml:"-"`
+	ctx    context.Context    `json:"-"      yaml:"-"`
+	cancel context.CancelFunc `json:"-"      yaml:"-"`
+	Lport  uint32             `json:"lport"  yaml:"lport"`
+	Dport  uint32             `json:"dport"  yaml:"dport"`
+	Dests  []*Destination     `json:"dests"  yaml:"dests"`
+	log    *logger.Logger
+}
+
+func NewForwarder(ctx context.Context, lport, dport uint32, addrs ...string) (*Forwarder, error) {
+	ctx, cancel := context.WithCancel(context.Background())
+	forw := &Forwarder{
+		Dests:  make([]*Destination, 0),
+		Lport:  lport,
+		Dport:  dport,
+		ctx:    ctx,
+		cancel: cancel,
+	}
+        id := strconv.FormatUint(uint64(lport), 10)
+	forw.log = logger.NewLogger("forwarder:" + id)
+	for _, addr := range addrs {
+		dest := NewDestination(addr)
+		forw.Dests = append(forw.Dests, dest)
+	}
+
+	portinfo := ":" + strconv.FormatUint(uint64(forw.Lport), 10)
+        laddr, err := net.ResolveTCPAddr("tcp", portinfo)
+	if err != nil {
+		return forw, err
+	}
+	listen, err := net.ListenTCP("tcp", laddr)
+	if err != nil {
+		return forw, err
+	}
+	forw.listen = listen
+	return forw, err
+}
+
+func (forw *Forwarder) Listen(wg *sync.WaitGroup) {
+	forw.log.Debugf("Start listening on %d", forw.Lport)
+	defer wg.Done()
+	for {
+		conn, err := forw.listen.Accept()
+		if err != nil {
+			forw.log.Errorf("Listen err: %v", err)
+			return
+		}
+		go forw.handle(forw.ctx, conn)
+	}
+}
+
+func (forw *Forwarder) Stop() error {
+	return forw.listen.Close()
+}
+
+type Streamer struct {
+        source string
+        dest string
+        ctx context.Context
+        cancel context.CancelFunc
+}
+
+func NewStreamer(ctx context.Context) *Streamer {
+        ctx, cancel := context.WithCancel(ctx)
+        return &Streamer{
+                ctx: ctx,
+                cancel: cancel,
+        }
+}
+
+func (forw *Forwarder) handle(ctx context.Context, inconn net.Conn) {
+	forw.log.Debugf("%s: Handle on %d started", inconn.RemoteAddr(), forw.Lport)
+	defer inconn.Close()
+	if len(forw.Dests) == 0 {
+		return
+	}
+	addrnum := rand.Uint32() % uint32(len(forw.Dests))
+	ipaddr := forw.Dests[addrnum].Address
+	dstaddr := ipaddr + ":" + strconv.FormatUint(uint64(forw.Dport), 10)
+	outconn, err := net.Dial("tcp", dstaddr)
+	if err != nil {
+		return
+	}
+        defer outconn.Close()
+	var wg sync.WaitGroup
+	wg.Add(1)
+	go forw.stream(&wg, inconn, outconn)
+	wg.Add(1)
+	go forw.stream(&wg, outconn, inconn)
+	wg.Wait()
+	forw.log.Debugf("Handler on %d stopped", forw.Lport)
+}
+
+func (forw *Forwarder) stream(wg *sync.WaitGroup, inconn io.Reader, outconn io.Writer) {
+	defer wg.Done()
+	_, err := copy(forw.ctx, outconn, inconn)
+	if err != nil {
+		forw.log.Errorf("Copy err: %v", err)
+	}
+}
+
+type Destination struct {
+	Address string `json:"address"  yaml:"address"`
+}
+
+func NewDestination(addr string) *Destination {
+	return &Destination{
+		Address: addr,
+	}
+}