It would be better if FreeBSD could have "interface altname feature" like Linux has.
Kyle Evans <kev...@freebsd.org>, 19 Kas 2023 Paz, 07:50 tarihinde şunu yazdı: > > On 11/18/23 19:15, Zhenlei Huang wrote: > > > > > >> On Nov 19, 2023, at 6:20 AM, Mina Galić <free...@igalic.co > >> <mailto:free...@igalic.co>> wrote: > >> > >> Hi folks, > >> > >> Linux has an "easy" way of telling if an interface has been renamed. > >> See cloud-init's is_renamed function: > >> https://github.com/canonical/cloud-init/blob/5496745b394f9b7b9eaf57fd619330d484ce2da8/cloudinit/net/__init__.py#L338-L350 > >> > >> <https://github.com/canonical/cloud-init/blob/5496745b394f9b7b9eaf57fd619330d484ce2da8/cloudinit/net/__init__.py#L338-L350> > >> This code reads /sys/class/net/<netif>/name_assign_type and if that is > >> 3 or 4, it's been renamed. > >> > >> I can't even think of an sensible way of replicating that. > >> I can only think of terrible / wrong way of finding it out: > >> > >> dmesg | grep "changing name to '<new-netif>'" > >> > >> a less terrible method would be to check for, say: > >> > >> sysctl dev.<new-netif>.0.%driver > >> > >> if that fails, we probably have a renamed interface… but we don't know > >> what it was renamed from, and this only works for *real* interfaces, > >> not for cloned devices, or epairs. > >> > >> Now, ignoring my terrible hacky attempts at command line tooling, I > >> would also happily accept a solution in C, which is fairly easily > >> accessible from Python, and which we already use to figure out the > >> uptime (or rather, the boottime): > >> https://github.com/canonical/cloud-init/blob/5496745b394f9b7b9eaf57fd619330d484ce2da8/cloudinit/util.py#L2073-L2105 > >> > >> <https://github.com/canonical/cloud-init/blob/5496745b394f9b7b9eaf57fd619330d484ce2da8/cloudinit/util.py#L2073-L2105> > >> > >> Looking forward to reading your ideas. > > > > FreeBSD currently does not preserve the old ( original ) name of > > interfaces if it is renamed ( either physical or cloned ones ). > > While there's an attempt https://reviews.freebsd.org/D28247 > > <https://reviews.freebsd.org/D28247> to get the device name (physical > > ones) but it is not perfect and not completed. > > > > So may I ask why you need to know if a network interface was renamed ? > > > > Just last week I found this quite a pain as well; once an interface has > been renamed, if it's not a pseudo-interface with an obvious group > there's no clear way, AFAICT, to determine which driver created it > without perusing pciconf output or whatnot and hopefully being able to > associate the NICs listed with the new names (easier when there's only > one NIC, of course). Kind of a pain when you're working on a remote > machine that you're not at all familiar with. > > Thanks, > > Kyle Evans >
