[ovs-dev] offset of 0x10001 in dpif_netlink_queue_to_priority

Matthias May matthias.may at neratec.com
Tue Jul 4 15:09:21 UTC 2017


Hi

I'm trying to map the vlan_pcp onto 802.11 tid.

net/wireless/util.c in mac80211 specifies:

>	/* 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;

However the function dpif_netlink_queue_to_priority in /lib/dpif-netlink.c sets:
>    if (queue_id < 0xf000) {
>        *priority = TC_H_MAKE(1 << 16, queue_id + 1);

With this the lowest skb_priority I can set is 0x10001, slightly over the magic values I need to use ;)

Why is this offset of 0x10000 + 1 in place?
Is something else in ovs about which I'm not aware dependant on this offset?

BR
Matthias


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