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Subject: Re: [PATCH v3] {nl,mac}80211: allow 4addr AP operation on crypto
 controlled devices
To:     Johannes Berg <johannes@sipsolutions.net>
Cc:     linux-wireless@vger.kernel.org
References: <1557307533-5795-1-git-send-email-mpubbise@codeaurora.org>
 <fd3addc01fc3f5362dba5771ee82659cf01c195b.camel@sipsolutions.net>
From:   Manikanta Pubbisetty <mpubbise@codeaurora.org>
Message-ID: <c8484254-f4f7-9955-e3f8-8a423cc6c325@codeaurora.org>
Date:   Fri, 31 May 2019 10:03:52 +0530
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On 5/14/2019 2:08 PM, Johannes Berg wrote:
> On Wed, 2019-05-08 at 14:55 +0530, Manikanta Pubbisetty wrote:
>> +++ b/net/mac80211/util.c
>> @@ -3795,7 +3795,9 @@ int ieee80211_check_combinations(struct ieee80211_sub_if_data *sdata,
>>   	}
>>   
>>   	/* Always allow software iftypes */
>> -	if (local->hw.wiphy->software_iftypes & BIT(iftype)) {
>> +	if (local->hw.wiphy->software_iftypes & BIT(iftype) ||
>> +	    (iftype == NL80211_IFTYPE_AP_VLAN &&
>> +	     local->hw.wiphy->flags & WIPHY_FLAG_4ADDR_AP)) {
>>   		if (radar_detect)
>>   			return -EINVAL;
> Shouldn't this check if 4addr is actually enabled too, like here:


Sure Johannes, I'll look into it.


>>   	case NETDEV_PRE_UP:
>> -		if (!(wdev->wiphy->interface_modes & BIT(wdev->iftype)))
>> +		if (!(wdev->wiphy->interface_modes & BIT(wdev->iftype)) &&
>> +		    !(wdev->iftype == NL80211_IFTYPE_AP_VLAN &&
>> +		      rdev->wiphy.flags & WIPHY_FLAG_4ADDR_AP &&
>> +		      wdev->use_4addr))
>>   			return notifier_from_errno(-EOPNOTSUPP);
> ?
> Or is there some reason it doesn't matter?
>
>> @@ -3439,6 +3438,11 @@ static int nl80211_new_interface(struct sk_buff *skb, struct genl_info *info)
>>   			return err;
>>   	}
>>   
>> +	if (!(rdev->wiphy.interface_modes & (1 << type)) &&
>> +	    !(type == NL80211_IFTYPE_AP_VLAN && params.use_4addr &&
>> +	      rdev->wiphy.flags & WIPHY_FLAG_4ADDR_AP))
>> +		return -EOPNOTSUPP;
>> +
> I also wonder if we shouldn't go "all in" and actually make the check
> something like
>
>    check_interface_allowed(iftype, 4addr):
>      if (iftype == AP_VLAN && 4addr)
>        return wiphy.flags & WIPHY_FLAG_4ADDR_AP;
>
>      else return wiphy.interface_modes & BIT(iftype);
>
> i.e. make it "you must have WIPHY_FLAG_4ADDR_AP to use 4-addr AP_VLAN
> interfaces", rather than "also allow it in this case".
>
> That would seem like the clearer semantics to me?


Yeah, it can be better; I'll check if this is feasible.


Thanks,

Manikanta