Return-Path: Message-ID: <52AC4425.7080109@ahsoftware.de> Date: Sat, 14 Dec 2013 12:42:29 +0100 From: Alexander Holler MIME-Version: 1.0 To: linux-bluetooth@vger.kernel.org Subject: Shouldn't bluez serialize connection/authorization attempts? Content-Type: text/plain; charset=ISO-8859-15; format=flowed Sender: linux-bluetooth-owner@vger.kernel.org List-ID: Hello, I've experienced a small problem which makes me wonder how userspace is expected to handle that. To explain the problem, I use simple-agent and rfcomm on the local side (Linux with bluez) and a remote device with a fixed pin (without user interaction, it refuses or allows connections based on the pin), but I think the underlying problem is independent of that configuration. Furthermore, I did a small patch to the local simple-agent: ----------------- diff --git a/test/simple-agent b/test/simple-agent index 854e1af..63b705b 100755 --- a/test/simple-agent +++ b/test/simple-agent @@ -64,8 +64,9 @@ class Agent(dbus.service.Object): in_signature="o", out_signature="s") def RequestPinCode(self, device): print("RequestPinCode (%s)" % (device)) - set_trusted(device) - return ask("Enter PIN Code: ") + #set_trusted(device) + #return ask("Enter PIN Code: ") + return "666" @dbus.service.method(AGENT_INTERFACE, in_signature="o", out_signature="u") ----------------- That means it now always returns 666 as pin without asking the user. This pin doesn't match the pin of the remote device. If I now call for i in $(seq 1 100); do rfcomm connect rfcomm666 aa:bb:cc:dd:ee:ff ; done in a shell, only one Pin request (the first) ends up at simple-agent but all connection attempts are refused. So besides the first connection attempt, all others do die somewhere where userspace has no control over. What happens is likely that connection attempts are refused by the remote side, because an ongoing connection or authorization attempt isn't finished while a new one arrives. The problem I see here is, that userspace has no control about what happens during a connection attempt. And userspace doesn't know if any other process just did a connection attempt too. How should userspace behave to make sure every connection attempt ends up in a pin-request for the user? Shouldn't those connection/pairing/authorization attempts to the same remote device be serialized by bluez? Regards, Alexander Holler