13.01.2016, 13:02, "Olivier Cochard-Labbé" <oliv...@cochard.me>:
> On Wed, Jan 13, 2016 at 9:45 AM, Alexander V. Chernikov <melif...@ipfw.ru>
> wrote:
>
>> I suspect the reason here is link state bridge handling.
>> ix0 does not seem to have IFCAP_LINKSTATE option but re(4) does. Probably
>> wlan0 doesn't have LINKSTATE option.
>> Code in bridge_linkcheck() doesn't handle the case with both "has link
>> state" and "no link state" interfaces well:
>> if reX is the only interface w/ IFCAP_LINKSTATE and it goes down, bridge
>> will also change its link state to down.
>> (However, bridge does not seem to have link state option itself, so
>> RT_LINK_IS_UP() macro should return true...)
>
> For validating your "IFCAP_LINKSTATE" hypothesis, I've plug an USB
> ethernet adapter ue(4) that didn't support IFCAP_LINKSTATE.
> And I've setup the bridge0 with wlan0 and ue0 (in place of re1): same bug
> triggered. I need to plug a cable for correct routing.
We discussed/investigated this behaviour on IRC. To summarise:
1) ip_tryforward() does check interface linkstate regardless of linkstate
capability
2) bridge linkcheck function does not seem to care about linkstate capability.
What happened in original case:
802.11 does not provide linkstate cap and actual linkstate value is 0 (unknown).
re0 does provide linkstate cap, so on link down, bridge_linkcheck() code
decided to set own linkstate as DOWN as well (has non-zero linkstate interface,
0 up).
On packet transmission. ip_tryforward() checked bridge0 state, found it to be
DOWN so the icmp_error() was triggered.
Attached patch fixes the problem, but I'm still thinking about better solution.
>
> root@fbsd-router:~ # ifconfig bridge0
> bridge0: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> metric 0 mtu
> 1500
> ether 02:6b:c0:de:b8:00
> inet 1.1.1.1 netmask 0xffffff00 broadcast 1.1.1.255
> nd6 options=9<PERFORMNUD,IFDISABLED>
> groups: bridge
> id 00:00:00:00:00:00 priority 32768 hellotime 2 fwddelay 15
> maxage 20 holdcnt 6 proto rstp maxaddr 2000 timeout 1200
> root id 00:00:00:00:00:00 priority 32768 ifcost 0 port 0
> member: ue0 flags=143<LEARNING,DISCOVER,AUTOEDGE,AUTOPTP>
> ifmaxaddr 0 port 7 priority 128 path cost 55
> member: wlan0 flags=143<LEARNING,DISCOVER,AUTOEDGE,AUTOPTP>
> ifmaxaddr 0 port 5 priority 128 path cost 33333
> root@fbsd-router:~ # ifconfig ue0
> ue0: flags=8943<UP,BROADCAST,RUNNING,PROMISC,SIMPLEX,MULTICAST> metric 0
> mtu 1500
> options=80008<VLAN_MTU,LINKSTATE>
> ether 00:19:fd:4e:77:4d
> nd6 options=29<PERFORMNUD,IFDISABLED,AUTO_LINKLOCAL>
> media: Ethernet autoselect (none)
> status: no carrier
>
> Regards,
> _______________________________________________
> freebsd-current@freebsd.org mailing list
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Index: /usr/src/sys/net/if_bridge.c
===================================================================
--- /usr/src/sys/net/if_bridge.c (revision 293659)
+++ /usr/src/sys/net/if_bridge.c (working copy)
@@ -3550,22 +3550,25 @@ static void
bridge_linkcheck(struct bridge_softc *sc)
{
struct bridge_iflist *bif;
- int new_link, hasls;
+ int new_link, nols;
BRIDGE_LOCK_ASSERT(sc);
new_link = LINK_STATE_DOWN;
- hasls = 0;
+ nols = 0;
/* Our link is considered up if at least one of our ports is active */
LIST_FOREACH(bif, &sc->sc_iflist, bif_next) {
- if (bif->bif_ifp->if_capabilities & IFCAP_LINKSTATE)
- hasls++;
+ if ((bif->bif_ifp->if_capabilities & IFCAP_LINKSTATE) == 0) {
+ /* XXX: Handle admin down? */
+ nols++;
+ continue;
+ }
if (bif->bif_ifp->if_link_state == LINK_STATE_UP) {
new_link = LINK_STATE_UP;
break;
}
}
- if (!LIST_EMPTY(&sc->sc_iflist) && !hasls) {
- /* If no interfaces support link-state then we default to up */
+ if (!LIST_EMPTY(&sc->sc_iflist) && nols != 0) {
+ /* If some ifaces don't support link-state then we default to up */
new_link = LINK_STATE_UP;
}
if_link_state_change(sc->sc_ifp, new_link);
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