Hi Marcel, On Tue, Jan 10, 2012 at 6:50 PM, Marcel Holtmann <marcel@xxxxxxxxxxxx> wrote: > Hi Luiz, > >> This use MSG_DONTROUTE to send a single message with highest possible >> priority without having to rely on socket options. >> >> This is useful for RFCOMM which relies on socket interface to send frames >> to L2CAP, but since some of this frames are actual commands that can >> timeout they should be sent as soon as possible. >> >> For userspace this also offer the convenience of not having to use >> setsockopt several times when only a single/some messages needs to be >> prioritize. > > are you sure that we are not mis-using the MSG_DONTROUTE flag? This is the reason Ive sent as RFC, man page says it is only define for protocols that route, but note that MSG_TRYHARD does map to the same value (4) so the meaning depend on the protocol. Perhaps creating a new flag e.g. MSG_HIGHPRIO would be acceptable? >> + priority = sk->sk_priority; >> + >> + /* MSG_DONTROUTE send message at maximum possible priority */ >> + if ((msg->msg_flags & MSG_DONTROUTE) && priority < HCI_PRIO_MAX - 1) >> + priority = HCI_PRIO_MAX - 1; >> + > > you need to enforce the same privilege check that SO_PRIORITY does. > Otherwise every single application can just go and overwrite it. Currently HCI_PRIO_MAX - 1 maps to the highest priority without requiring privileges, but I can change that to HCI_PRIO_MAX so only privileged processes such bluetoothd can make use of it. -- Luiz Augusto von Dentz -- To unsubscribe from this list: send the line "unsubscribe linux-bluetooth" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
