[quagga-users 14963] Re: Duplication of kernel routes

Stefan Bethke <[email protected]> Thu, 8 Mar 2018 13:08:53 +0100
Newsgroups gmane.network.quagga.user
Message-ID <[email protected]>
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It appears the issue was triggered by configuring a GUA on the router's =
interface, and pointing the default route of the hosts in the VLAN to =
that GUA.

Using RAs and having the default route point at the LLA of the router's =
interface stopped the weird routing table entries.

> Am 16.01.2018 um 19:48 schrieb Stefan Bethke <[email protected]>:
>=20
> Hello,
>=20
> I=E2=80=99m running into a peculiar problem I=E2=80=99m hoping someone =
can give me some pointers for further diagnostics, or even ways to =
mitigate.
>=20
> I=E2=80=99m running quagga-1.1.1-68.1 on SLES11SP4, =
3.0.101-108.21-default #1 SMP Thu Jan 11 12:58:47 CET 2018 x86_64, with =
current patches. zebra, ospfd, ospf6d and bpd are running.
>=20
> I can reproduce the issue on a VSphere VM with 3 vmxnet interfaces; =
two of which are bonded as a active/backup pair. On the production =
machine, it=E2=80=99s two bonded interfaces with LACP. The production =
setup is a pair of machines with keepalived, where VLANs are split =
between both nodes (odd/even VLAN numbers).
>=20
> The router receives a full table.
> ip -4 route show | wc -l: 669651
> ip -6 route show | wc -l: 43739
>=20
> There=E2=80=99s quite a number of customer machines connected to =
various VLANs; only a single VLAN is producing this effect.
>=20
> The problem presents like this: whenever one of the customer FreeBSD =
11.1 machines has an active IPv6 configuration, the number of IPv6 =
kernel routes in the router balloons. Every about 30 seconds, the number =
of routes increases by one full table size (so adding about 45,000); at =
some point, the entire IPv6 table gets reset and the process starts =
over. IPv4 appears to be completely unaffected. Other customers machines =
with FreeBSD do not exhibit this problem, nor do any other Ones.
>=20
> The FreeBSD configuration appears to be standard: NDP and auto link =
local are active and working seemingly OK; no routing protocol is =
active. With NUD active, there are about 5-10 NDP packets per minute, =
all confirming reachability with solicited requests. With NUD off, the =
frequency drops to about 2 NDP packets per minute. The customer VLAN has =
about 4 MACs active, two of which are locally administered.
> # ifconfig bridge0 inet6
> bridge0: flags=3D8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> metric 0 =
mtu 1500
> 	description: vm-bridge0
> 	inet6 fe80::3c:9fff:fe37:2500%bridge0/64 scopeid 0x7
> 	inet6 2a00:14b0:4200:xyza::1e1/64
> 	inet6 2a00:14b0:4200:xyza::1e2/128
> 	inet6 2a00:14b0:4200:xyza::1fd/128
> 	inet6 2a00:14b0:4200:xyza::1e5/128
> 	nd6 options=3D8020<AUTO_LINKLOCAL,DEFAULTIF>
> # ndp -i bridge0
> linkmtu=3D0, maxmtu=3D0, curhlim=3D64, basereachable=3D30s0ms, =
reachable=3D43s, retrans=3D1s0ms
> Flags: auto_linklocal
>=20
> The effect stops within minutes once both machines=E2=80=99 IPv6 =
interfaces are disabled.
>=20
> tcpdump/wireshark traces don=E2=80=99t seem to be showing anything out =
of the ordinary. Traffic on the VLAN is very moderate.
>=20
> What=E2=80=99s puzzling to me is that there are lots of identical =
duplicate routes installed in the kernel:
> # ip -6 route show | grep 2a00:14b0:4200:xyza
> 2a00:14b0:4200:xyza::/64 dev vlan503  proto kernel  metric 256
> 2a00:14b0:4200:xyza::/64 dev vlan503  proto kernel  metric 256
> 2a00:14b0:4200:xyza::/64 dev vlan503  proto kernel  metric 256
> 2a00:14b0:4200:xyza::/64 dev vlan503  proto kernel  metric 256
> 2a00:14b0:4200:xyza::/64 dev vlan503  proto kernel  metric 256
> 2a00:14b0:4200:xyza::/64 dev vlan503  proto kernel  metric 256
> 2a00:14b0:4200:xyza::/64 dev vlan503  proto kernel  metric 256
> 2a00:14b0:4200:xyza::/64 dev vlan503  proto kernel  metric 256
> 2a00:14b0:4200:xyza::/64 dev vlan503  proto kernel  metric 256
> 2a00:14b0:4200:xyza::/64 dev vlan503  proto kernel  metric 256
> 2a00:14b0:4200:xyza::/64 dev vlan503  proto kernel  metric 256
> 2a00:14b0:4200:xyza::/64 dev vlan503  proto kernel  metric 256
> 2a00:14b0:4200:xyza::/64 dev vlan503  proto kernel  metric 256
> 2a00:14b0:4200:xyza::/64 dev vlan503  proto kernel  metric 256
> 2a00:14b0:4200:xyza::/64 dev vlan503  proto kernel  metric 256
> 2a00:14b0:4200:xyza::/64 dev vlan503  proto kernel  metric 256
> 2a00:14b0:4200:xyza::/64 dev vlan503  proto kernel  metric 256
> 2a00:14b0:4200:xyza::/64 dev vlan503  proto kernel  metric 256
> 2a00:14b0:4200:xyza::/64 dev vlan503  proto kernel  metric 256
> 2a00:14b0:4200:xyza::/64 dev vlan503  proto kernel  metric 256
> 2a00:14b0:4200:xyza::/64 dev vlan503  proto kernel  metric 256
> ^C
>=20
> I=E2=80=99m at a loss how and why these duplicate routes should be =
installed.  I would appreciate any hints on how to diagnose this =
further.
>=20
> The following versions of quagga were tried, without any change in =
behaviour:
> # 2012-10-02 17:21:35 quagga-0.99.15-0.10.1.x86_64.rpm installed ok
> # 2013-01-14 18:55:55 quagga-0.99.15-0.12.1.x86_64.rpm installed ok
> # 2013-09-27 18:27:25 quagga-0.99.15-0.14.1.x86_64.rpm installed ok
> # 2015-08-26 16:40:56 quagga-0.99.15-0.14.11.x86_64.rpm installed ok
> # 2016-04-06 15:40:30 quagga-0.99.15-0.21.1.x86_64.rpm installed ok
> # 2016-06-08 10:45:33 quagga-0.99.15-0.24.2.x86_64.rpm installed ok
> # 2016-10-26 14:55:44 quagga-0.99.15-0.29.1.x86_64.rpm installed ok
> # 2017-04-18 15:48:51 quagga-1.1.1-65.1.x86_64.rpm installed ok
> # 2017-12-12 16:41:30 quagga-1.1.1-68.1.x86_64.rpm installed ok
>=20
>=20
> Thanks,
> Stefan
>=20
> --
> Stefan Bethke <[email protected]>   Fon +49 151 14070811
>=20
>=20
> _______________________________________________
> Quagga-users mailing list
> Quagga-users-UOy77sIEA+cAd7ICUelF/[email protected]
> https://lists.quagga.net/mailman/listinfo/quagga-users

--=20
Stefan Bethke <[email protected]>   Fon +49 151 14070811



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<html><head><meta http-equiv=3D"Content-Type" content=3D"text/html =
charset=3Dutf-8"></head><body style=3D"word-wrap: break-word; =
-webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" =
class=3D"">It appears the issue was triggered by configuring a GUA on =
the router's interface, and pointing the default route of the hosts in =
the VLAN to that GUA.<div class=3D""><br class=3D""></div><div =
class=3D"">Using RAs and having the default route point at the LLA of =
the router's interface stopped the weird routing table =
entries.</div><div class=3D""><br class=3D""><div><blockquote =
type=3D"cite" class=3D""><div class=3D"">Am 16.01.2018 um 19:48 schrieb =
Stefan Bethke &lt;<a href=3D"mailto:[email protected]" =
class=3D"">[email protected]</a>&gt;:</div><br =
class=3D"Apple-interchange-newline"><div class=3D""><div =
class=3D"">Hello,<br class=3D""><br class=3D"">I=E2=80=99m running into =
a peculiar problem I=E2=80=99m hoping someone can give me some pointers =
for further diagnostics, or even ways to mitigate.<br class=3D""><br =
class=3D"">I=E2=80=99m running quagga-1.1.1-68.1 on SLES11SP4, =
3.0.101-108.21-default #1 SMP Thu Jan 11 12:58:47 CET 2018 x86_64, with =
current patches. zebra, ospfd, ospf6d and bpd are running.<br =
class=3D""><br class=3D"">I can reproduce the issue on a VSphere VM with =
3 vmxnet interfaces; two of which are bonded as a active/backup pair. On =
the production machine, it=E2=80=99s two bonded interfaces with LACP. =
The production setup is a pair of machines with keepalived, where VLANs =
are split between both nodes (odd/even VLAN numbers).<br class=3D""><br =
class=3D"">The router receives a full table.<br class=3D"">ip -4 route =
show | wc -l: 669651<br class=3D"">ip -6 route show | wc -l: 43739<br =
class=3D""><br class=3D"">There=E2=80=99s quite a number of customer =
machines connected to various VLANs; only a single VLAN is producing =
this effect.<br class=3D""><br class=3D"">The problem presents like =
this: whenever one of the customer FreeBSD 11.1 machines has an active =
IPv6 configuration, the number of IPv6 kernel routes in the router =
balloons. Every about 30 seconds, the number of routes increases by one =
full table size (so adding about 45,000); at some point, the entire IPv6 =
table gets reset and the process starts over. IPv4 appears to be =
completely unaffected. Other customers machines with FreeBSD do not =
exhibit this problem, nor do any other Ones.<br class=3D""><br =
class=3D"">The FreeBSD configuration appears to be standard: NDP and =
auto link local are active and working seemingly OK; no routing protocol =
is active. With NUD active, there are about 5-10 NDP packets per minute, =
all confirming reachability with solicited requests. With NUD off, the =
frequency drops to about 2 NDP packets per minute. The customer VLAN has =
about 4 MACs active, two of which are locally administered.<br =
class=3D""># ifconfig bridge0 inet6<br class=3D"">bridge0: =
flags=3D8843&lt;UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST&gt; metric 0 mtu =
1500<br class=3D""><span class=3D"Apple-tab-span" =
style=3D"white-space:pre">	</span>description: vm-bridge0<br =
class=3D""><span class=3D"Apple-tab-span" style=3D"white-space:pre">	=
</span>inet6 fe80::3c:9fff:fe37:2500%bridge0/64 scopeid 0x7<br =
class=3D""><span class=3D"Apple-tab-span" style=3D"white-space:pre">	=
</span>inet6 2a00:14b0:4200:xyza::1e1/64<br class=3D""><span =
class=3D"Apple-tab-span" style=3D"white-space:pre">	</span>inet6 =
2a00:14b0:4200:xyza::1e2/128<br class=3D""><span class=3D"Apple-tab-span" =
style=3D"white-space:pre">	</span>inet6 =
2a00:14b0:4200:xyza::1fd/128<br class=3D""><span class=3D"Apple-tab-span" =
style=3D"white-space:pre">	</span>inet6 =
2a00:14b0:4200:xyza::1e5/128<br class=3D""><span class=3D"Apple-tab-span" =
style=3D"white-space:pre">	</span>nd6 =
options=3D8020&lt;AUTO_LINKLOCAL,DEFAULTIF&gt;<br class=3D""># ndp -i =
bridge0<br class=3D"">linkmtu=3D0, maxmtu=3D0, curhlim=3D64, =
basereachable=3D30s0ms, reachable=3D43s, retrans=3D1s0ms<br =
class=3D"">Flags: auto_linklocal<br class=3D""><br class=3D"">The effect =
stops within minutes once both machines=E2=80=99 IPv6 interfaces are =
disabled.<br class=3D""><br class=3D"">tcpdump/wireshark traces don=E2=80=99=
t seem to be showing anything out of the ordinary. Traffic on the VLAN =
is very moderate.<br class=3D""><br class=3D"">What=E2=80=99s puzzling =
to me is that there are lots of identical duplicate routes installed in =
the kernel:<br class=3D""># ip -6 route show | grep =
2a00:14b0:4200:xyza<br class=3D"">2a00:14b0:4200:xyza::/64 dev vlan503 =
&nbsp;proto kernel &nbsp;metric 256<br class=3D"">2a00:14b0:4200:xyza::/64=
 dev vlan503 &nbsp;proto kernel &nbsp;metric 256<br =
class=3D"">2a00:14b0:4200:xyza::/64 dev vlan503 &nbsp;proto kernel =
&nbsp;metric 256<br class=3D"">2a00:14b0:4200:xyza::/64 dev vlan503 =
&nbsp;proto kernel &nbsp;metric 256<br class=3D"">2a00:14b0:4200:xyza::/64=
 dev vlan503 &nbsp;proto kernel &nbsp;metric 256<br =
class=3D"">2a00:14b0:4200:xyza::/64 dev vlan503 &nbsp;proto kernel =
&nbsp;metric 256<br class=3D"">2a00:14b0:4200:xyza::/64 dev vlan503 =
&nbsp;proto kernel &nbsp;metric 256<br class=3D"">2a00:14b0:4200:xyza::/64=
 dev vlan503 &nbsp;proto kernel &nbsp;metric 256<br =
class=3D"">2a00:14b0:4200:xyza::/64 dev vlan503 &nbsp;proto kernel =
&nbsp;metric 256<br class=3D"">2a00:14b0:4200:xyza::/64 dev vlan503 =
&nbsp;proto kernel &nbsp;metric 256<br class=3D"">2a00:14b0:4200:xyza::/64=
 dev vlan503 &nbsp;proto kernel &nbsp;metric 256<br =
class=3D"">2a00:14b0:4200:xyza::/64 dev vlan503 &nbsp;proto kernel =
&nbsp;metric 256<br class=3D"">2a00:14b0:4200:xyza::/64 dev vlan503 =
&nbsp;proto kernel &nbsp;metric 256<br class=3D"">2a00:14b0:4200:xyza::/64=
 dev vlan503 &nbsp;proto kernel &nbsp;metric 256<br =
class=3D"">2a00:14b0:4200:xyza::/64 dev vlan503 &nbsp;proto kernel =
&nbsp;metric 256<br class=3D"">2a00:14b0:4200:xyza::/64 dev vlan503 =
&nbsp;proto kernel &nbsp;metric 256<br class=3D"">2a00:14b0:4200:xyza::/64=
 dev vlan503 &nbsp;proto kernel &nbsp;metric 256<br =
class=3D"">2a00:14b0:4200:xyza::/64 dev vlan503 &nbsp;proto kernel =
&nbsp;metric 256<br class=3D"">2a00:14b0:4200:xyza::/64 dev vlan503 =
&nbsp;proto kernel &nbsp;metric 256<br class=3D"">2a00:14b0:4200:xyza::/64=
 dev vlan503 &nbsp;proto kernel &nbsp;metric 256<br =
class=3D"">2a00:14b0:4200:xyza::/64 dev vlan503 &nbsp;proto kernel =
&nbsp;metric 256<br class=3D"">^C<br class=3D""><br class=3D"">I=E2=80=99m=
 at a loss how and why these duplicate routes should be installed. =
&nbsp;I would appreciate any hints on how to diagnose this further.<br =
class=3D""><br class=3D"">The following versions of quagga were tried, =
without any change in behaviour:<br class=3D""># 2012-10-02 17:21:35 =
quagga-0.99.15-0.10.1.x86_64.rpm installed ok<br class=3D""># 2013-01-14 =
18:55:55 quagga-0.99.15-0.12.1.x86_64.rpm installed ok<br class=3D""># =
2013-09-27 18:27:25 quagga-0.99.15-0.14.1.x86_64.rpm installed ok<br =
class=3D""># 2015-08-26 16:40:56 quagga-0.99.15-0.14.11.x86_64.rpm =
installed ok<br class=3D""># 2016-04-06 15:40:30 =
quagga-0.99.15-0.21.1.x86_64.rpm installed ok<br class=3D""># 2016-06-08 =
10:45:33 quagga-0.99.15-0.24.2.x86_64.rpm installed ok<br class=3D""># =
2016-10-26 14:55:44 quagga-0.99.15-0.29.1.x86_64.rpm installed ok<br =
class=3D""># 2017-04-18 15:48:51 quagga-1.1.1-65.1.x86_64.rpm installed =
ok<br class=3D""># 2017-12-12 16:41:30 quagga-1.1.1-68.1.x86_64.rpm =
installed ok<br class=3D""><br class=3D""><br class=3D"">Thanks,<br =
class=3D"">Stefan<br class=3D""><br class=3D"">--<br class=3D"">Stefan =
Bethke &lt;<a href=3D"mailto:[email protected]" =
class=3D"">[email protected]</a>&gt; &nbsp;&nbsp;Fon +49 151 14070811<br =
class=3D""><br class=3D""><br =
class=3D"">_______________________________________________<br =
class=3D"">Quagga-users mailing list<br class=3D""><a =
href=3D"mailto:Quagga-users-UOy77sIEA+cAd7ICUelF/[email protected]" =
class=3D"">Quagga-users-UOy77sIEA+cAd7ICUelF/[email protected]</a><br =
class=3D"">https://lists.quagga.net/mailman/listinfo/quagga-users<br =
class=3D""></div></div></blockquote></div><br class=3D""><div class=3D"">
<div style=3D"color: rgb(0, 0, 0); font-family: 'Andale Mono'; =
font-size: 12px; font-style: normal; font-variant-caps: normal; =
font-weight: normal; letter-spacing: normal; orphans: auto; text-align: =
start; text-indent: 0px; text-transform: none; white-space: normal; =
widows: auto; word-spacing: 0px; -webkit-text-size-adjust: auto; =
-webkit-text-stroke-width: 0px;">--&nbsp;<br class=3D"">Stefan Bethke =
&lt;<a href=3D"mailto:[email protected]" class=3D"">[email protected]</a>&gt; =
&nbsp; Fon&nbsp;+49 151 14070811<br class=3D""><br class=3D""></div>

</div>
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