Date: Tue, 10 Apr 2018 18:28:11 +0200 From: Luca Pizzamiglio <pizzamig@freebsd.org> To: "Bjoern A. Zeeb" <bzeeb-lists@lists.zabbadoz.net> Cc: Giulio Ferro <auryn@zirakzigil.org>, "freebsd-net@freebsd.org" <freebsd-net@freebsd.org>, FreeBSD Hackers <freebsd-hackers@freebsd.org> Subject: Re: Duplicate MAC addresses in VNET epair interaces Message-ID: <CAB88xy9-1%2BwsHFkt=YNdqh==XQSXsMr=E3YjD1qch0mpqzKxvQ@mail.gmail.com> In-Reply-To: <8B1A6A6C-4280-4B96-9D60-FC9E7EEE2222@lists.zabbadoz.net> References: <472069af-0f9d-d830-064b-2d984a5774ae@zirakzigil.org> <8B1A6A6C-4280-4B96-9D60-FC9E7EEE2222@lists.zabbadoz.net>
next in thread | previous in thread | raw e-mail | index | archive | help
Hi. I have the same problem. The arc4random() call was committed and reverted ( https://svnweb.freebsd.org/base/head/sys/net/if_epair.c?view=3Dlog) I have a patch, that I'm currently using, that solves the issue locally (available here https://pastebin.com/LpPEVJL7 ) To be more generic, I'd like to add some hostid bits, following the approach of if_bridge, in case your epair interface has to be connected to a LAN. best regards, pizzamig On Mon, Feb 6, 2017 at 8:53 PM, Bjoern A. Zeeb < bzeeb-lists@lists.zabbadoz.net> wrote: > On 6 Feb 2017, at 18:53, Giulio Ferro wrote: > > Hi all, >> >> >> Setup: >> >> 11.0-STABLE FreeBSD 11.0-STABLE #0 r312338: Tue Jan 17 12:29:38 UTC 2017 >> >> >> I've set up two freebsd hosts, each of which has a single VNET jail. >> >> On each host I've created 2 epair interfaces. >> >> Host A >> >> - epair0a, epair1a on the host >> >> - epair0b, epair1b on the jail >> >> >> Host B >> >> - epair0a, epair10a on the host >> >> - epair0b, epair10b on the jail >> >> >> What I noticed is that on both hosts, each epair interface has the same >> MAC address: >> >> =E2=80=A6> > >> >> (same behavior on the epair interfaces on the jail side) >> >> >> As you can see, the mac addresses seems to depend on the order of the >> creation of the epair, not on the name or address >> >> >> This is a potentially bad behavior, because if I want to bridge say >> epair1a on A with epair10a on B with a VPN or >> >> a physical connection giving 192.168.1.1 to epair1b and 192.168.1.2 to >> epair10b, I won't be able to make them >> >> talk to each other since they have the same MAC address. >> >> >> My question is: is this a bug or something I'm doing wrong? If there any >> workaround I can use? >> > > > From the man page: > > Like any other Ethernet interface, an epair needs to have a network > address. Each epair will be assigned a locally administered address > by > default, that is only guaranteed to be unique within one network > stack. > To change the default addresses one may use the SIOCSIFADDR ioctl(2) > or > ifconfig(8) utility. > > I thought someone patched it a few years ago to have a pseudo-random part > to make collisions less likely and use the FreeBSD vendor space, but it > seems that never happened for epair (or didn=E2=80=99t make it into the t= ree). > > ifconfig epair<x>[ab] ether 02:xx:xx:xx:xx is your friend for now. > > /bz > > _______________________________________________ > freebsd-hackers@freebsd.org mailing list > https://lists.freebsd.org/mailman/listinfo/freebsd-hackers > To unsubscribe, send any mail to "freebsd-hackers-unsubscribe@freebsd.org= " >
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?CAB88xy9-1%2BwsHFkt=YNdqh==XQSXsMr=E3YjD1qch0mpqzKxvQ>