ola,
while your explanation is good it still makes my head hurt. i think it makes
sense, but i will throw it on a box here to try. we use both numbered and
unnumbered carpdevs.
dlg
> On 28 Oct 2014, at 23:56, Henning Brauer <hb-openbsdt...@ml.bsws.de> wrote:
>
> so, carp interface with underlaying unnumbered carpdev, i. e.
>
> ifconfig em1 up
> ifconfig carp0 carpdev em1 vhid 0 ... 10.0.0.1/24
>
> carp announcements and some stuff like arp goes out with the carp
> interface mac address, fine.
> however, IP traffic goes out with the carpdev's mac, which is wrong
> and leads to problems in places with a strict mac address regime -
> exchange points are a typical case.
>
> the culprit is sys/net/if_ethersubr.c ether_output().
>
> The ifp passed to ether_output is (usually) determined by looking up
> the route to the destination and grabbing the ifp from it. So in the
> numbered carpdev case (em1 10.0.0.x/24, carp 10.0.0.y/32) it'll be the
> carpdev (em1 here) right away. In the unnumbered carpdev case, it'll be
> the carp interface itself. ether_output has a hack to exchange the carp
> ifp with the carpdev's one, to send out the frame on the carpdev and
> not the carp if. This little hack is before the src mac address is
> determined tho, and that is the bug.
>
> ok?
>
> Index: if_ethersubr.c
> ===================================================================
> RCS file: /cvs/src/sys/net/if_ethersubr.c,v
> retrieving revision 1.175
> diff -u -p -r1.175 if_ethersubr.c
> --- if_ethersubr.c 7 Oct 2014 20:23:32 -0000 1.175
> +++ if_ethersubr.c 28 Oct 2014 12:18:36 -0000
> @@ -270,6 +270,8 @@ ether_output(struct ifnet *ifp0, struct
> senderr(EBUSY);
> #endif
>
> + esrc = ac->ac_enaddr;
> +
> #if NCARP > 0
> if (ifp->if_type == IFT_CARP) {
> ifp = ifp->if_carpdev;
> @@ -310,7 +312,6 @@ ether_output(struct ifnet *ifp0, struct
> time_second < rt->rt_rmx.rmx_expire)
> senderr(rt == rt0 ? EHOSTDOWN : EHOSTUNREACH);
> }
> - esrc = ac->ac_enaddr;
> switch (dst->sa_family) {
>
> #ifdef INET
>
>
> --
> Henning Brauer, h...@bsws.de, henn...@openbsd.org
> BS Web Services GmbH, http://bsws.de, Full-Service ISP
> Secure Hosting, Mail and DNS. Virtual & Dedicated Servers, Root to Fully
> Managed
> Henning Brauer Consulting, http://henningbrauer.com/
>
