netlink: Indicate that ifinfomsg uses IFT_* types
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Authored by emaste on May 29 2026, 4:29 PM.

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bz
pouria
melifaro

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network

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rGd7356667931e: netlink: Indicate that ifinfomsg uses IFT_* types
rG76f29211f0dd: netlink: Indicate that ifinfomsg uses IFT_* types
rG21a75a85f0e0: netlink: Indicate that ifinfomsg uses IFT_* types

Summary

On Linux struct ifinfomsg uses ARPHRD_* values, while we used IFT_*
types (which derive from SNMP ifType definitions in RFC 1573).
Update the header to reflect this.

PR:             272144

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emaste created this revision.May 29 2026, 4:29 PM

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emaste requested review of this revision.May 29 2026, 4:29 PM

netlink specs clearly want to use arp types (ARPHRD_*). (See include/uapi/linux/rtnetlink.h of linux)
However, IMO, using arp types are not appropriate here, because we actually want to get the actual interface type ifp->if_type.
therefore our current implementation (IFT_*) is correct.

We also provide compatibility for linux.
For example we map our IFT_ETHER to ARPHDR_ETHER type in sys/compat/linux/linux_netlink.c:366.

This should be enough reasoning/evidence for PR272144.
Please add a note here to clarify that NOT using ARPHRD_* is intentional.
This should also close that PR too.

This revision is now accepted and ready to land.May 29 2026, 9:21 PM

Don't forget to update the comment on the man page for rtnetlink(4).