allocation policy of PACKET_TAG_* values

[Manuel Bouyer <bouyer%antioche.eu.org@localhost>]

Hello,
for socketcan implementation I need to record a pointer of the
sender socket in the mbuf. A m_tag seems appropriate for this.
I plan to add a PACKET_TAG_SO type.

What is the policy for allocating a new PACKET_TAG value ?
I see that values 4-10 are free for example, PACKET_TAG_PF being 11.
Can I use 4 ? If not what value should I use ?

-- 
Manuel Bouyer <bouyer%antioche.eu.org@localhost>
     NetBSD: 26 ans d'experience feront toujours la difference
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