New: redir proxy

proxy/redir/tcp_linux_386.go

@@ -0,0 +1,17 @@
+package redir
+
+import (
+	"syscall"
+	"unsafe"
+)
+
+const GETSOCKOPT = 15 // https://golang.org/src/syscall/syscall_linux_386.go#L183
+
+func socketcall(call, a0, a1, a2, a3, a4, a5 uintptr) error {
+	var a [6]uintptr
+	a[0], a[1], a[2], a[3], a[4], a[5] = a0, a1, a2, a3, a4, a5
+	if _, _, errno := syscall.Syscall6(syscall.SYS_SOCKETCALL, call, uintptr(unsafe.Pointer(&a)), 0, 0, 0, 0); errno != 0 {
+		return errno
+	}
+	return nil
+}