more mbuf flags

[Robert Swindells <rjs%fdy2.co.uk@localhost>]

I want to use an mbuf flag as part of adding sctp support. My current
plan is to use M_PROTO1 for this.

The M_PROTO1 flag is used in a few places in the tree:

In sys/net/if_bridge.c it is set for all enqueued mbufs. This was
introduced in 1.28 as part of a patch to allow gif(4) interfaces to be
members of a bridge, the rest of the patch has gone now but not this
line.

In sys/netbt/hci_link.c it is set to indicate that an mbuf is a first
fragment and checked later.

In the iee80211(4) stack and drivers it is used to indicate that the
mbuf contains a PS_POLL packet and some wireless drivers test for it.

I think the if_bridge.c usage should be deleted.

All the other current usages seem to me to be features of a link, not
a protocol and ought to be changed to use one of the M_LINK* flags in
order to free up M_PROTO1 for use by actual protocols.

Thoughts ?

Robert Swindells