add socks

pkg/handler/socks/v5/bind.go

@@ -0,0 +1,160 @@
+package v5
+
+import (
+	"context"
+	"net"
+
+	"github.com/go-gost/gosocks5"
+	"github.com/go-gost/gost/pkg/handler"
+	"github.com/go-gost/gost/pkg/logger"
+)
+
+func (h *socks5Handler) handleBind(ctx context.Context, conn net.Conn, req *gosocks5.Request) {
+	addr := req.Addr.String()
+
+	h.logger = h.logger.WithFields(map[string]interface{}{
+		"dst": addr,
+		"cmd": "bind",
+	})
+
+	h.logger.Infof("%s >> %s", conn.RemoteAddr(), addr)
+
+	if h.chain.IsEmpty() {
+		h.bindLocal(ctx, conn, addr)
+		return
+	}
+
+	r := (&handler.Router{}).
+		WithChain(h.chain).
+		WithRetry(h.md.retryCount).
+		WithLogger(h.logger)
+	cc, err := r.Connect(ctx)
+	if err != nil {
+		resp := gosocks5.NewReply(gosocks5.Failure, nil)
+		resp.Write(conn)
+		if h.logger.IsLevelEnabled(logger.DebugLevel) {
+			h.logger.Debug(resp)
+		}
+		return
+	}
+	defer cc.Close()
+
+	if err := req.Write(cc); err != nil {
+		h.logger.Error(err)
+		resp := gosocks5.NewReply(gosocks5.NetUnreachable, nil)
+		resp.Write(conn)
+		if h.logger.IsLevelEnabled(logger.DebugLevel) {
+			h.logger.Debug(resp)
+		}
+		return
+	}
+
+	h.logger.Infof("%s <-> %s", conn.RemoteAddr(), addr)
+	handler.Transport(conn, cc)
+	h.logger.Infof("%s >-< %s", conn.RemoteAddr(), addr)
+}
+
+func (h *socks5Handler) bindLocal(ctx context.Context, conn net.Conn, addr string) {
+	bindAddr, _ := net.ResolveTCPAddr("tcp", addr)
+	ln, err := net.ListenTCP("tcp", bindAddr) // strict mode: if the port already in use, it will return error
+	if err != nil {
+		h.logger.Error(err)
+		reply := gosocks5.NewReply(gosocks5.Failure, nil)
+		if err := reply.Write(conn); err != nil {
+			h.logger.Error(err)
+		}
+		if h.logger.IsLevelEnabled(logger.DebugLevel) {
+			h.logger.Debug(reply.String())
+		}
+		return
+	}
+
+	socksAddr, err := gosocks5.NewAddr(ln.Addr().String())
+	if err != nil {
+		h.logger.Warn(err)
+		socksAddr = &gosocks5.Addr{
+			Type: gosocks5.AddrIPv4,
+		}
+	}
+
+	// Issue: may not reachable when host has multi-interface
+	socksAddr.Host, _, _ = net.SplitHostPort(conn.LocalAddr().String())
+	reply := gosocks5.NewReply(gosocks5.Succeeded, socksAddr)
+	if err := reply.Write(conn); err != nil {
+		h.logger.Error(err)
+		ln.Close()
+		return
+	}
+	if h.logger.IsLevelEnabled(logger.DebugLevel) {
+		h.logger.Debug(reply.String())
+	}
+	h.logger.Infof("bind on: %s OK", socksAddr.String())
+
+	h.serveBind(ctx, conn, ln)
+}
+
+func (h *socks5Handler) serveBind(ctx context.Context, conn net.Conn, ln net.Listener) {
+	var rc net.Conn
+	accept := func() <-chan error {
+		errc := make(chan error, 1)
+
+		go func() {
+			defer close(errc)
+			defer ln.Close()
+
+			c, err := ln.Accept()
+			if err != nil {
+				errc <- err
+			}
+			rc = c
+		}()
+
+		return errc
+	}
+
+	pc1, pc2 := net.Pipe()
+	pipe := func() <-chan error {
+		errc := make(chan error, 1)
+
+		go func() {
+			defer close(errc)
+			defer pc1.Close()
+
+			errc <- handler.Transport(conn, pc1)
+		}()
+
+		return errc
+	}
+
+	defer pc2.Close()
+
+	select {
+	case err := <-accept():
+		if err != nil {
+			h.logger.Error(err)
+			return
+		}
+		defer rc.Close()
+
+		raddr, _ := gosocks5.NewAddr(rc.RemoteAddr().String())
+		reply := gosocks5.NewReply(gosocks5.Succeeded, raddr)
+		if err := reply.Write(pc2); err != nil {
+			h.logger.Error(err)
+		}
+		if h.logger.IsLevelEnabled(logger.DebugLevel) {
+			h.logger.Debug(reply.String())
+		}
+		h.logger.Infof("PEER %s ACCEPTED", raddr.String())
+
+		h.logger.Infof("%s <-> %s", conn.RemoteAddr(), raddr.String())
+		handler.Transport(pc2, rc)
+		h.logger.Infof("%s >-< %s", conn.RemoteAddr(), raddr.String())
+
+	case err := <-pipe():
+		if err != nil {
+			h.logger.Error(err)
+		}
+		ln.Close()
+		return
+	}
+}