[dev] discard interface warnings on FreeBSD

Fri Apr 26 16:42:22 EDT 2019

I have been using the discard interface - DISC(4) - on FreeBSD for some
time to tie down supernets. On frr7, I am getting a warning message at
startup I am not sure what to make of

The nic is configured as

# ifconfig disc0
disc0: flags=8049<UP,LOOPBACK,RUNNING,MULTICAST> metric 0 mtu 65532
        inet 10.128.128.144 netmask 0xfffffff8
        inet 10.129.129.1 netmask 0xfffffff0
        inet6 2001:db8::1 prefixlen 64
        inet6 fe80::1%disc0 prefixlen 64 scopeid 0x7
        groups: disc
        nd6 options=21<PERFORMNUD,AUTO_LINKLOCAL>

And at startup, I get

 /usr/local/etc/rc.d/frr start
Checking zebra.conf
2019/04/26 15:58:44 warnings: ZEBRA: [EC 4043309141] warning: interface
disc0 broadcast addr 10.128.128.144/29 != calculated 10.128.128.151,
routing protocols may malfunction
2019/04/26 15:58:44 warnings: ZEBRA: [EC 4043309141] warning: interface
disc0 broadcast addr 10.129.129.1/28 != calculated 10.129.129.15,
routing protocols may malfunction
2019/04/26 15:58:44 warnings: ZEBRA: [EC 4043309105] Disabling MPLS
support (no kernel support)
OK
Starting zebra.
2019/04/26 15:58:44 warnings: ZEBRA: [EC 4043309141] warning: interface
disc0 broadcast addr 10.128.128.144/29 != calculated 10.128.128.151,
routing protocols may malfunction
2019/04/26 15:58:44 warnings: ZEBRA: [EC 4043309141] warning: interface
disc0 broadcast addr 10.129.129.1/28 != calculated 10.129.129.15,
routing protocols may malfunction
2019/04/26 15:58:44 warnings: ZEBRA: [EC 4043309105] Disabling MPLS
support (no kernel support)

If I use the same IP info on another non discard interface it works /
doesnt complain.

Also, when starting staticd, I get these warnings as well.

Checking staticd.conf
2019/04/26 15:58:44 warnings: STATIC: void
static_zebra_nht_register(struct static_route *, _Bool): Failure to send
nexthop to zebra
2019/04/26 15:58:44 warnings: STATIC: void
static_zebra_nht_register(struct static_route *, _Bool): Failure to send
nexthop to zebra
2019/04/26 15:58:44 warnings: STATIC: void
static_zebra_nht_register(struct static_route *, _Bool): Failure to send
nexthop to zebra
2019/04/26 15:58:44 warnings: STATIC: void
static_zebra_nht_register(struct static_route *, _Bool): Failure to send
nexthop to zebra
2019/04/26 15:58:44 warnings: STATIC: void
static_zebra_nht_register(struct static_route *, _Bool): Failure to send
nexthop to zebra
2019/04/26 15:58:44 warnings: STATIC: void
static_zebra_nht_register(struct static_route *, _Bool): Failure to send
nexthop to zebra
2019/04/26 15:58:44 warnings: STATIC: void
static_zebra_nht_register(struct static_route *, _Bool): Failure to send
nexthop to zebra
2019/04/26 15:58:44 warnings: STATIC: void
static_zebra_nht_register(struct static_route *, _Bool): Failure to send
nexthop to zebra
2019/04/26 15:58:44 warnings: STATIC: void
static_zebra_nht_register(struct static_route *, _Bool): Failure to send
nexthop to zebra
2019/04/26 15:58:44 warnings: STATIC: void
static_zebra_nht_register(struct static_route *, _Bool): Failure to send
nexthop to zebra
2019/04/26 15:58:44 warnings: STATIC: void
static_zebra_nht_register(struct static_route *, _Bool): Failure to send
nexthop to zebra
2019/04/26 15:58:44 warnings: STATIC: void
static_zebra_nht_register(struct static_route *, _Bool): Failure to send
nexthop to zebra
2019/04/26 15:58:44 warnings: STATIC: void
static_zebra_nht_register(struct static_route *, _Bool): Failure to send
nexthop to zebra
2019/04/26 15:58:44 warnings: STATIC: void
static_zebra_nht_register(struct static_route *, _Bool): Failure to send
nexthop to zebra
2019/04/26 15:58:44 warnings: STATIC: void
static_zebra_nht_register(struct static_route *, _Bool): Failure to send
nexthop to zebra
2019/04/26 15:58:44 warnings: STATIC: void
static_zebra_nht_register(struct static_route *, _Bool): Failure to send
nexthop to zebra
2019/04/26 15:58:44 warnings: STATIC: void
static_zebra_nht_register(struct static_route *, _Bool): Failure to send
nexthop to zebra
2019/04/26 15:58:44 warnings: STATIC: void
static_zebra_nht_register(struct static_route *, _Bool): Failure to send
nexthop to zebra
2019/04/26 15:58:44 warnings: STATIC: void
static_zebra_nht_register(struct static_route *, _Bool): Failure to send
nexthop to zebra
OK
Starting staticd.

Looking at the installed routes, it looks ok, except for one which I
must be missing something obvious, but its ok on quagga and frr6

I have interface

igb1.6: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> metric 0 mtu 1500
        options=600703<RXCSUM,TXCSUM,TSO4,TSO6,LRO,RXCSUM_IPV6,TXCSUM_IPV6>
        ether 90:e2:ba:01:37:81
        inet6 fe80::92e2:baff:fe01:3781%igb1.6 prefixlen 64 scopeid 0xe
        inet 64.7.149.177 netmask 0xfffffffc broadcast 64.7.149.179

and a static route of

ip route 10.87.1.0/30 64.7.149.178

It ends up installing this static route on the discard interface for
some reason on frr7.  On frr6, it works. next hop is 64.7.149.178. I do
get the same warning messages however at  startup. On frr5, its the same
as frr7. 

# vtysh -c "show ip route 10.87.1.0/30"
Routing entry for 10.87.1.0/30
  Known via "static", distance 1, metric 0, best
  Last update 00:00:14 ago
    64.7.149.178 (recursive)
  *   10.129.129.1, via disc0

kernel confirms

# netstat -nr | grep ^10.87.1.
10.87.1.0/30       10.129.129.1       UG1       disc0

#

Any ideas what up ?  As this is just a test box, there is no MAC addr
for the next hop, but would it not mark the route as inactive rather
than change the next hop to the discard interface ?

    ---Mike

-- 
-------------------
Mike Tancsa, tel +1 519 651 3400 x203
Sentex Communications, mike at sentex.net
Providing Internet services since 1994 www.sentex.net
Cambridge, Ontario Canada   