diff --git a/internal/netconn/pipe.go b/internal/netconn/pipe.go
new file mode 100644
index 0000000..511df03
--- /dev/null
+++ b/internal/netconn/pipe.go
@@ -0,0 +1,54 @@
+package netconn
+
+import (
+	"context"
+	"io"
+	"net"
+	"sync"
+	"time"
+)
+
+// BiCopy runs io.Copy in both directions between c1 and c2, returning
+// (bytesC1FromC2, bytesC2FromC1). When either copy exits — by EOF, error, or
+// ctx cancellation — both sides get their deadlines pinned to time.Now() so the
+// peer goroutine unblocks. Errors are surfaced via errf when non-nil.
+func BiCopy(ctx context.Context, c1, c2 net.Conn, errf func(format string, v ...any)) (int64, int64) {
+	ctx2, cancel := context.WithCancel(ctx)
+	context.AfterFunc(ctx2, func() {
+		now := time.Now()
+		if err := c1.SetDeadline(now); err != nil && errf != nil {
+			errf("BiCopy: c1 SetDeadline: %v", err)
+		}
+		if err := c2.SetDeadline(now); err != nil && errf != nil {
+			errf("BiCopy: c2 SetDeadline: %v", err)
+		}
+	})
+
+	var wg sync.WaitGroup
+	var c1FromC2, c2FromC1 int64
+	wg.Go(func() {
+		defer cancel()
+		n, err := io.Copy(c1, c2)
+		c1FromC2 = n
+		if err != nil && errf != nil {
+			errf("BiCopy: c1<-c2: %v", err)
+		}
+	})
+	wg.Go(func() {
+		defer cancel()
+		n, err := io.Copy(c2, c1)
+		c2FromC1 = n
+		if err != nil && errf != nil {
+			errf("BiCopy: c2<-c1: %v", err)
+		}
+	})
+	wg.Wait()
+
+	if err := c1.SetDeadline(time.Time{}); err != nil && errf != nil {
+		errf("BiCopy: c1 clear deadline: %v", err)
+	}
+	if err := c2.SetDeadline(time.Time{}); err != nil && errf != nil {
+		errf("BiCopy: c2 clear deadline: %v", err)
+	}
+	return c1FromC2, c2FromC1
+}
diff --git a/internal/proxy/tcpfwd/tcpfwd.go b/internal/proxy/tcpfwd/tcpfwd.go
index e701ae7..e44e31e 100644
--- a/internal/proxy/tcpfwd/tcpfwd.go
+++ b/internal/proxy/tcpfwd/tcpfwd.go
@@ -3,13 +3,13 @@ package tcpfwd
 import (
 	"context"
 	"fmt"
-	"io"
 	"net"
 	"sync"
 	"time"
 
 	"github.com/cacggghp/vk-turn-proxy/internal/client/ish"
 	"github.com/cacggghp/vk-turn-proxy/internal/logx"
+	"github.com/cacggghp/vk-turn-proxy/internal/netconn"
 	"github.com/cacggghp/vk-turn-proxy/internal/proxy/common"
 	"github.com/cacggghp/vk-turn-proxy/internal/stats"
 	"github.com/cacggghp/vk-turn-proxy/internal/transport/dtlsdial"
@@ -162,7 +162,12 @@ func Run(ctx context.Context, deps *Deps, params *Params, peer *net.UDPAddr, lis
 				return
 			}
 			defer func() { _ = stream.Close() }()
-			fromSession, toSession := pipe(deps, ctx, tc, stream)
+			errf := func(format string, v ...any) {
+				if deps.log().DebugEnabled() {
+					deps.log().Errorf(format, v...)
+				}
+			}
+			fromSession, toSession := netconn.BiCopy(ctx, tc, stream, errf)
 			sessRef.FromSession.Add(uint64(fromSession))
 			sessRef.ToSession.Add(uint64(toSession))
 			deps.log().Debugf("[session %d] TCP done #%d local<-session=%s local->session=%s",
@@ -275,44 +280,3 @@ func createSmuxSession(ctx context.Context, deps *Deps, params *Params, peer *ne
 	return smuxSess, cleanup, nil
 }
 
-// pipe copies data bidirectionally between two connections, cancelling both
-// sides as soon as either copy finishes. Returns (c1<-c2, c2<-c1) bytes.
-func pipe(deps *Deps, ctx context.Context, c1, c2 net.Conn) (int64, int64) {
-	ctx2, cancel := context.WithCancel(ctx)
-	context.AfterFunc(ctx2, func() {
-		if err := c1.SetDeadline(time.Now()); err != nil {
-			deps.log().Errorf("pipe: failed to set deadline c1: %v", err)
-		}
-		if err := c2.SetDeadline(time.Now()); err != nil {
-			deps.log().Errorf("pipe: failed to set deadline c2: %v", err)
-		}
-	})
-
-	var wg sync.WaitGroup
-	var c1FromC2 int64
-	var c2FromC1 int64
-	wg.Go(func() {
-		defer cancel()
-		n, err := io.Copy(c1, c2)
-		c1FromC2 = n
-		if err != nil && deps.log().DebugEnabled() {
-			deps.log().Errorf("pipe: c1<-c2 copy error: %v", err)
-		}
-	})
-	wg.Go(func() {
-		defer cancel()
-		n, err := io.Copy(c2, c1)
-		c2FromC1 = n
-		if err != nil && deps.log().DebugEnabled() {
-			deps.log().Errorf("pipe: c2<-c1 copy error: %v", err)
-		}
-	})
-	wg.Wait()
-	if err := c1.SetDeadline(time.Time{}); err != nil && deps.log().DebugEnabled() {
-		deps.log().Errorf("pipe: failed to reset deadline c1: %v", err)
-	}
-	if err := c2.SetDeadline(time.Time{}); err != nil && deps.log().DebugEnabled() {
-		deps.log().Errorf("pipe: failed to reset deadline c2: %v", err)
-	}
-	return c1FromC2, c2FromC1
-}
diff --git a/internal/proxy/tcpfwdserver/tcpfwdserver.go b/internal/proxy/tcpfwdserver/tcpfwdserver.go
index 0eed048..8de770e 100644
--- a/internal/proxy/tcpfwdserver/tcpfwdserver.go
+++ b/internal/proxy/tcpfwdserver/tcpfwdserver.go
@@ -12,6 +12,7 @@ import (
 	"time"
 
 	"github.com/cacggghp/vk-turn-proxy/internal/logx"
+	"github.com/cacggghp/vk-turn-proxy/internal/netconn"
 	"github.com/cacggghp/vk-turn-proxy/internal/proxy/bondserver"
 	"github.com/cacggghp/vk-turn-proxy/internal/stats"
 	"github.com/cacggghp/vk-turn-proxy/internal/transport/kcptun"
@@ -110,7 +111,7 @@ func handleStream(ctx context.Context, logger logx.Logger, registry *bondserver.
 		}
 	}()
 
-	pipeConn(ctx, logger, &prefixedConn{Conn: s, prefix: prefix[:]}, backendConn)
+	netconn.BiCopy(ctx, &prefixedConn{Conn: s, prefix: prefix[:]}, backendConn, logger.Debugf)
 }
 
 // prefixedConn re-injects the magic-peek prefix on the first reads so the
@@ -129,37 +130,3 @@ func (c *prefixedConn) Read(p []byte) (int, error) {
 	return c.Conn.Read(p)
 }
 
-// pipeConn copies data bidirectionally between two connections.
-func pipeConn(ctx context.Context, logger logx.Logger, c1, c2 net.Conn) {
-	ctx2, cancel := context.WithCancel(ctx)
-	defer cancel()
-
-	context.AfterFunc(ctx2, func() {
-		if err := c1.SetDeadline(time.Now()); err != nil {
-			logger.Debugf("pipeConn: failed to set deadline c1: %v", err)
-		}
-		if err := c2.SetDeadline(time.Now()); err != nil {
-			logger.Debugf("pipeConn: failed to set deadline c2: %v", err)
-		}
-	})
-
-	var wg sync.WaitGroup
-	wg.Go(func() {
-		if _, err := io.Copy(c1, c2); err != nil {
-			logger.Debugf("pipeConn: c1<-c2 copy error: %v", err)
-		}
-	})
-	wg.Go(func() {
-		if _, err := io.Copy(c2, c1); err != nil {
-			logger.Debugf("pipeConn: c2<-c1 copy error: %v", err)
-		}
-	})
-	wg.Wait()
-
-	if err := c1.SetDeadline(time.Time{}); err != nil {
-		logger.Debugf("pipeConn: failed to reset deadline c1: %v", err)
-	}
-	if err := c2.SetDeadline(time.Time{}); err != nil {
-		logger.Debugf("pipeConn: failed to reset deadline c2: %v", err)
-	}
-}