Date: Sun, 19 Nov 2023 12:54:49 +0300 From: =?UTF-8?B?w5Z6a2FuIEtJUklL?= <ozkan.kirik@gmail.com> To: Kyle Evans <kevans@freebsd.org> Cc: freebsd-net@freebsd.org Subject: Re: How to tell if a network interface was renamed (and from what) Message-ID: <CAAcX-AE4rFhO4RGVVFSZJcgQK=qCg-Aucx5QO-wbX1%2B3Ag38Nw@mail.gmail.com> In-Reply-To: <9eef5488-e8da-4edd-bc00-baeb5aaf4a23@FreeBSD.org> References: <pdHC0ObBkAbx2HfFIhWYaB5-dmQDEUzNTWvVVJAuJV7FWdWWeSwybVFD-uyBUxPlqDRpAW7D1aAZsbrTxEj9kqsq7ESgO41srPmS-PcXGqw=@igalic.co> <E5F5F61E-3827-404A-A46F-BBCF45A29A82@FreeBSD.org> <9eef5488-e8da-4edd-bc00-baeb5aaf4a23@FreeBSD.org>
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It would be better if FreeBSD could have "interface altname feature" like Linux has. Kyle Evans <kevans@freebsd.org>, 19 Kas 2023 Paz, 07:50 tarihinde =C5=9Funu= yazd=C4=B1: > > On 11/18/23 19:15, Zhenlei Huang wrote: > > > > > >> On Nov 19, 2023, at 6:20 AM, Mina Gali=C4=87 <freebsd@igalic.co > >> <mailto:freebsd@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/5496745b394f9b7b9eaf57fd6= 19330d484ce2da8/cloudinit/net/__init__.py#L338-L350 <https://github.com/can= onical/cloud-init/blob/5496745b394f9b7b9eaf57fd619330d484ce2da8/cloudinit/n= et/__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=E2=80=A6 but we do= n'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/5496745b394f9b7b9eaf57fd6= 19330d484ce2da8/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 >
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