Move catch blocks to child classes

This reverts commit 07a48bc20b and f870093c94.

mobile/src/main/java/com/github/shadowsocks/bg/VpnService.kt

@@ -55,13 +55,18 @@ class VpnService : BaseVpnService(), LocalDnsService.Interface {
         override val socketFile: File = File(filesDir, "protect_path")
 
         override fun accept(socket: LocalSocket) {
-            socket.inputStream.read()
-            val fds = socket.ancillaryFileDescriptors
-            if (fds.isEmpty()) return
-            val fd = getInt.invoke(fds.first()) as Int
-            val ret = protect(fd)
-            JniHelper.close(fd) // Trick to close file decriptor
-            socket.outputStream.write(if (ret) 0 else 1)
+            try {
+                socket.inputStream.read()
+                val fds = socket.ancillaryFileDescriptors
+                if (fds.isEmpty()) return
+                val fd = getInt.invoke(fds.first()) as Int
+                val ret = protect(fd)
+                JniHelper.close(fd) // Trick to close file decriptor
+                socket.outputStream.write(if (ret) 0 else 1)
+            } catch (e: Exception) {
+                Log.e(tag, "Error when protect socket", e)
+                app.track(e)
+            }
         }
     }
     class NullConnectionException : NullPointerException()