Re: skb->priority usage in wireless frame classification
From: Helmut Schaa <hidden>
Date: 2011-12-16 09:42:20
Also in:
linux-wireless
On Fri, Dec 16, 2011 at 10:35 AM, Dave Taht [off-list ref] wrote:
On Fri, Dec 16, 2011 at 9:45 AM, Helmut Schaa [off-list ref] wrote:quoted
[Adding netdev] Maybe someone from the netdev people can shed some light on this. We've got the following code in net/wireless/util.c for frame classification (cfg80211_classify8021d): /* skb->priority values from 256->263 are magic values to * directly indicate a specific 802.1d priority. This is used * to allow 802.1d priority to be passed directly in from VLAN * tags, etc. */ if (skb->priority >= 256 && skb->priority <= 263) return skb->priority - 256; I was just thinking about making use of this for some internal mac80211 QoS handling. But is this code still valid? At least I haven't found anything in the 802.1q code :(I made use of the above 'feature' while prototyping some Diffserv work with iptables. I have no idea if there are users of this obscure overloading of priority in userspace.... The vlan code at least used to do something like this: net/8021q/vlan.h: * @vlan_qos: vlan priority: (skb->priority << 13) & 0xE000
Yeah, I saw that too but +256 would be << 8 and not << 13. Helmut -- To unsubscribe from this list: send the line "unsubscribe linux-wireless" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html