WPA Supplicant not able to listen to events from driver

Naveen Singh naveen at nestlabs.com
Fri Feb 6 16:24:03 EST 2015


Thanks it worked. But looks like every time we load the driver, phy index
kept on incrementing.
Regards
Naveen

On Fri, Feb 6, 2015 at 12:47 AM, Arend van Spriel <arend at broadcom.com>
wrote:

> On 02/06/15 04:22, Naveen Singh wrote:
>
>> Hi All
>> For my system we have cfg80211 built as loadable module. When we unload
>> our WLAN driver cfg80211 gets unloaded as well.
>>
>
> So how is your WLAN driver unloaded. When unloading cfg80211 the nl80211
> netlink family is unregistered from the kernel probably closing all
> user-space netlink sockets.
>
> If you only 'rmmod' your WLAN driver than supplicant should be fine
> handling it as cfg80211 is not unloaded. If you use 'modprobe -r' it will
> unload dependent modules if their refcount is zero.
>
> Regards,
> Arend
>
>  After reloading the
>> driver I found that none of the events from driver never makes to
>> supplicant. I see that connect command from supplicant makes to driver
>> but the NL_CONNECT_CMD netlink message from the driver is dropped. On
>> further debugging I found that the messages are dropped in the following
>> function sd it does not call *do_one_broadcast*. Looks like all the
>> previous bindings were lost. After killing the supplicant and restarting
>> the supplicant I can see that the subscriptions are updated and
>> connection succeeded.
>>
>> int netlink_broadcast_filtered(struct sock *ssk, struct sk_buff *skb,
>> u32 portid,
>> u32 group, gfp_t allocation,
>> int (*filter)(struct sock *dsk, struct sk_buff *skb, void *data),
>> void *filter_data)
>> {
>> struct net *net = sock_net(ssk);
>> struct netlink_broadcast_data info;
>> struct sock *sk;
>>
>> skb = netlink_trim(skb, allocation);
>>
>> info.exclude_sk = ssk;
>> info.net <http://info.net> = net;
>> info.portid = portid;
>> info.group = group;
>> info.failure = 0;
>> info.delivery_failure = 0;
>> info.congested = 0;
>> info.delivered = 0;
>> info.allocation = allocation;
>> info.skb = skb;
>> info.skb2 = NULL;
>> info.tx_filter = filter;
>> info.tx_data = filter_data;
>>
>> /* While we sleep in clone, do not allow to change socket list */
>>
>> netlink_lock_table();
>>
>> sk_for_each_bound(sk, &nl_table[ssk->sk_protocol].mc_list)
>> d*o_one_broadcast(sk, &info); ==> This function is not called at all as
>> it does not find any subscription at all. *
>>
>> consume_skb(skb);
>>
>> netlink_unlock_table();
>>
>> if (info.delivery_failure) {
>> kfree_skb(info.skb2);
>> return -ENOBUFS;
>> }
>> consume_skb(info.skb2);
>>
>> if (info.delivered) {
>> if (info.congested && (allocation & __GFP_WAIT))
>> yield();
>> My feeling is that as cfg80211 gets unloaded as well when driver is
>> unloaded, it loses all the subscription and hence none of the message
>> from driver gets ever delivered to supplicant. But what surprises me is
>> that although we cannot send messages from driver to supplicant it is
>> not true in reverse direction. Connect command from supplicant lands in
>> driver. Has anyone seen something similar? I have a workaround right now
>> where i restart the supplicant whenever i unload and load the driver.
>> But I would like to have a cleaner solution.
>>
>>
>> Regards
>> Naveen
>>
>>
>>
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>
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