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en:developers:p2p:p2p-interface-notes [2015/01/26 09:49] (current)
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 +**Note: The design on this page is WIP: [[http://​​gmane.linux.kernel.wireless.general/​93044|http://​​gmane.linux.kernel.wireless.general/​93044]]** ​
 +===== Design notes on dedicated P2P interface API =====
 +==== Rationale ====
 +Some drivers/​devices would like to 
 +  * use a separate MAC address ​
 +  * use a separate control path for P2P usage. This could even help mac80211-based drivers like iwlagn since currently, iwlagn needs to enable P2P in the device when a remain-on-channel is done, and disable it after a timeout or when a P2P interface is used. 
 +==== API notes ====
 +A separate netdev would be the most obvious choice, but can be confusing: ​
 +    * to the user -- new interface is there, what does it do? 
 +    * to the developer -- no data traffic on this interface ​
 +Better: use dedicated API in nl80211: ​
 +      * start-P2P -> returns cookie ​
 +      * stop-P2P -> uses cookie ​
 +(or maybe don't have "​stop-P2P"​ but simply stop when socket is closed like mgmt frame subscriptions) ​
 +The only issue with this is that things like scan, mgmt-tx etc. need a netdev index now. However, this can be changed, idea: 
 +        * use cookie to identify the P2P device interface ​
 +        * internally, create a <​code>​struct wireless_dev</​code>​ but **without** a netdev ​
 +        * modify cfg80211 API (e.g. <​code>​scan</​code>,​ <​code>​remain_on_channel</​code>​) to take <​code>​struct wireless_dev</​code>​ instead of netdev, driver can check what the type is etc. 
 +        * this needs separate P2P-device iftype that can't really be used as an iftype, which is fine Questions: ​
 +          * lifetime: does the P2P-device interface become the P2P-group/​client interface like in wpa_supplicant,​ which means that it is removed before/when the real netdev is added? (personally I prefer it would stay around I think since I think discovery/​public action things would still be done with it, not the real interface -- Johannes) ​
 +          * pure software implementation of this in mac80211 for drivers that don't care, to unify API? but wpa_s needs old code anyway for backward compatibility ​
 +==== additional thoughts ====
 +This could also be a good framework for additional features that we'll need to add: 
 +            * device-based P2P listen/​search timing (soon) ​
 +            * maybe some more P2P offloads (WoP2P anyone? :-) ) 
en/developers/p2p/p2p-interface-notes.txt ยท Last modified: 2015/01/26 09:49 (external edit)