2008-07-17 09:33:44

by Mateusz

[permalink] [raw]
Subject: RFCOMM connection timeout question (rfcomm/sock.c)


I'm trying to understand the following piece of kernel code in rfcomm/sock.c.

rfcomm_sock_connect -> rfcomm_dlc_open -> bt_sock_wait_state

The last procedure waits until the sk's state changes to BT_CONNECTED.

1. When creating sk socket the sk_sndtimeo member of sk is initialized
to RFCOMM_CONN_TIMEOUT, which in my kernel code is HZ * 30 which, as I
see it, should be 30 seconds. However after enabling debug, I can see
that the timeout returned by sock_sndtimeo is 7500. How could this

2. What is the role of the bt_sock_wait_state? If timeout expires it
returns error code 115 (EINPROGRESS). What does the situation look
like here? Is the client still trying to connect to a remote device?
If so, how should the client program handle this error code? Is
ignoring it a good option or should it rather call the
rfcomm_socket_release function? What would happen if the client tried
to connect to the same remote device using rfcomm_sock_connect after
receiving this error code? Is there a way to notify the client that
the connection was made (BT_CONNECTED) without waiting on the
bt_sock_wait_state function.

3. Is there a way to control this timeout in a more flexible fashion
or is it impossible due to some BT specification bits?

Thanks in advance for all the answers. Your support and suggestions
are greatly appreciated.

Best wishes,