Mailing List Archive: IPv6 BGP routes from a directly connected peer are not accepted in the routing table

IPv6 BGP routes from a directly connected peer are not accepted in the routing table

May 17, 2017, 7:46 AM

Post #1 of 6 (2315 views)

Hi to all of you,

Apologies for cross-posting already to the dev list.

I am using quagga 1.2.1 on a freebsd (10.3) as provided from an already
compiled packaged. In a simple set up of two connected routers where I
setup a direct external bgp peering, the routes are exchanged but are
not established in the routing table as their bgp_nhop is reported as
inaccesible although it is received from a connected interface.

See the attached image. The configuration of two routers follows..

!
router-a@pc-dkalo:~
! Zebra configuration saved from vty
! 2017/05/16 16:50:22
!
!
interface em0
ipv6 address fc80:1::1/64
!
interface em1
ipv6 address fc80:3::1/126
!
interface em2
!
interface em3
!
interface lo0
!
ip forwarding
ipv6 forwarding
!
!
line vty
!
!
! Zebra configuration saved from vty
! 2017/05/16 16:50:22
!
!
router bgp 65010
bgp router-id 1.1.1.1
neighbor fc80:3::2 remote-as 65020
! neighbor fc80:3::2 soft-reconfiguration inbound
!
address-family ipv6
network fc80:1::/64
neighbor fc80:3::2 activate
! neighbor fc80:3::2 soft-reconfiguration inbound
exit-address-family
exit
!
line vty
!
router-b@pc-dkalo:~#
!
! Zebra configuration saved from vty
! 2017/05/16 17:49:55
!
!
interface em0
ipv6 address fc80:2::1/64
!
interface em1
ipv6 address fc80:3::2/126
!
interface em2
!
interface em3
!
interface lo0
!
ipv6 forwarding
!
!
line vty
!
!
! Zebra configuration saved from vty
! 2017/05/16 17:49:55
!
!
router bgp 65020
bgp router-id 2.2.2.2
neighbor fc80:3::1 remote-as 65010
!
address-family ipv6
network fc80:2::/64
neighbor fc80:3::1 activate
exit-address-family
exit
!
line vty
!

Do you believe there is an error in the configuration ? or is it a bug ?

Cheers,
Dimitris

--
Dimitrios K. Kalogeras

Electrical Engineer Ph.D.
Network Engineer
NTUA/ICCS
_____________________________________
skype: aweboy
voice: +30-210-772 1863
fax: +30-210-772 1866

Re: IPv6 BGP routes from a directly connected peer are not accepted in the routing table [ In reply to ]

alarig at swordarmor

May 17, 2017, 8:38 AM

Post #2 of 6 (2315 views)

Permalink

On mer. 17 mai 17:46:46 2017, Dimitris Kalogeras wrote:
> router bgp 65010
> bgp router-id 1.1.1.1
> neighbor fc80:3::2 remote-as 65020
> ! neighbor fc80:3::2 soft-reconfiguration inbound
> !
> address-family ipv6
> network fc80:1::/64
> neighbor fc80:3::2 activate
> ! neighbor fc80:3::2 soft-reconfiguration inbound
> exit-address-family
> exit

Hi,

I activate the IPv6 neighbors in the address-family context, but
configuring it in the normal context:

router bgp 204092
bgp router-id 193.200.42.229
neighbor 130.117.20.2 remote-as 174
neighbor 130.117.20.2 password <blah>
neighbor 130.117.20.2 ebgp-multihop 15
neighbor 2001:550:0:1000::8275:1402 remote-as 174
neighbor 2001:550:0:1000::8275:1402 password <blah>
neighbor 2001:550:0:1000::8275:1402 ebgp-multihop 15
no neighbor 2001:550:0:1000::8275:1402 activate
!
address-family ipv6
neighbor 2001:550:0:1000::8275:1402 activate
exit-address-family

I don’t export routes to kernel as it is a blackholing session, but you
can try something like that.

--
alarig

Re: IPv6 BGP routes from a directly connected peer are not accepted in the routing table [ In reply to ]

olivier at cochard

Jun 23, 2017, 8:58 AM

Post #3 of 6 (2277 views)

Permalink

On Wed, May 17, 2017 at 4:46 PM, Dimitris Kalogeras <D.Kalogeras@noc.ntua.gr
> wrote:

>
> Do you believe there is an error in the configuration ? or is it a bug ?
>
>
?I've got exactly the same problem (Quagga 1.2.1 on FreeBSD 11.1-BETA2):

R2# sh bgp neighbors 2001:db8:23::3 received-routes
BGP table version is 0, local router ID is 192.168.56.12
Status codes: s suppressed, d damped, h history, * valid, > best, =
multipath,
i internal, r RIB-failure, S Stale, R Removed
Origin codes: i - IGP, e - EGP, ? - incomplete

Network Next Hop Metric LocPrf Weight Path
*> 2001:db8:3::/64 2001:db8:23::3 0 100 0 i
*> 2001:db8:34::/64 2001:db8:23::3 0 100 0 i

Total number of prefixes 2
R2# sh ipv6 bgp 2001:db8:34::/64
BGP routing table entry for 2001:db8:34::/64
Paths: (1 available, no best path)
Not advertised to any peer
Local
2001:db8:23::3 (inaccessible) from 2001:db8:23::3 (10.0.3.3)
(fe80::5a9c:fcff:fe02:303)
Origin IGP, metric 0, localpref 100, invalid, internal
Last update: Fri Jun 23 17:55:43 2017

Regards,
Olivier

Re: IPv6 BGP routes from a directly connected peer are not accepted in the routing table [ In reply to ]

q-u at opsec

Jun 23, 2017, 11:02 AM

Post #4 of 6 (2277 views)

Permalink

Hi!

> ???I've got exactly the same problem (Quagga 1.2.1 on FreeBSD 11.1-BETA2):
>
> R2# sh bgp neighbors 2001:db8:23::3 received-routes
> BGP table version is 0, local router ID is 192.168.56.12
> Status codes: s suppressed, d damped, h history, * valid, > best, =
> multipath,
> i internal, r RIB-failure, S Stale, R Removed
> Origin codes: i - IGP, e - EGP, ? - incomplete
>
> Network Next Hop Metric LocPrf Weight Path
> *> 2001:db8:3::/64 2001:db8:23::3 0 100 0 i
> *> 2001:db8:34::/64 2001:db8:23::3 0 100 0 i
>
> Total number of prefixes 2
> R2# sh ipv6 bgp 2001:db8:34::/64
> BGP routing table entry for 2001:db8:34::/64
> Paths: (1 available, no best path)
> Not advertised to any peer
> Local
> 2001:db8:23::3 (inaccessible) from 2001:db8:23::3 (10.0.3.3)
> (fe80::5a9c:fcff:fe02:303)
> Origin IGP, metric 0, localpref 100, invalid, internal
> Last update: Fri Jun 23 17:55:43 2017

Please check, there's this well-known bug:

https://bugzilla.quagga.net/show_bug.cgi?id=870

https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=214481

--
pi@opsec.eu +49 171 3101372 3 years to go !
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Re: IPv6 BGP routes from a directly connected peer are not accepted in the routing table [ In reply to ]

mf at 14v

Sep 14, 2017, 2:03 PM

Post #5 of 6 (2203 views)

Permalink

> Hi!
>
> > ???I've got exactly the same problem (Quagga 1.2.1 on FreeBSD
> > 11.1-BETA2):
> >
> > R2# sh bgp neighbors 2001:db8:23::3 received-routes
> > BGP table version is 0, local router ID is 192.168.56.12
> > Status codes: s suppressed, d damped, h history, * valid, > best, =
> > multipath,
> > i internal, r RIB-failure, S Stale, R Removed
> > Origin codes: i - IGP, e - EGP, ? - incomplete
> >
> > Network Next Hop Metric LocPrf Weight Path
> > *> 2001:db8:3::/64 2001:db8:23::3 0 100 0 i
> > *> 2001:db8:34::/64 2001:db8:23::3 0 100 0 i
> >
> > Total number of prefixes 2
> > R2# sh ipv6 bgp 2001:db8:34::/64
> > BGP routing table entry for 2001:db8:34::/64
> > Paths: (1 available, no best path)
> > Not advertised to any peer
> > Local
> > 2001:db8:23::3 (inaccessible) from 2001:db8:23::3 (10.0.3.3)
> > (fe80::5a9c:fcff:fe02:303)
> > Origin IGP, metric 0, localpref 100, invalid, internal
> > Last update: Fri Jun 23 17:55:43 2017
>
> Please check, there's this well-known bug:
>
> https://bugzilla.quagga.net/show_bug.cgi?id=870
>
> https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=214481

Hi,

not sure if this is the same as quagga bz#870 - I haven't (yet) seen
OutQ stuck at >0.

But I have encountered the same "inaccessible" ipv6 nexthops problem as
above, but on Linux.

Suspect log entries:

2017/09/14 21:06:28 [10070] BGP: bgp_ensure_nexthop: NHT could not ensure, failed to get rn!
2017/09/14 21:06:28 [10070] BGP: bgp_update_main(0.0.0.0): NH unresolved

I could resolve that by comparing the bgp_ensure_nexthop() function in
bgp/bgp_nht.c to the counterpart bgp_find_or_add_nexthop() function from
FRR, and then cherrypicking something that seemed related to ipv6 link
local nexthops.

I don't claim to fully understand the code, and I hope I am not
infringing on the copyright of the author of that code. Patch is
attached.

Regards
Matthias

Re: IPv6 BGP routes from a directly connected peer are not accepted in the routing table [ In reply to ]

mf at 14v

Sep 15, 2017, 7:18 AM

Post #6 of 6 (2202 views)

Permalink

On Thu, Sep 14, 2017 at 11:03:07PM +0200, Matthias Ferdinand wrote:
> not sure if this is the same as quagga bz#870 - I haven't (yet) seen
> OutQ stuck at >0.

now I can say that the patch only fixes the "inaccessible" problem, but
not the bz#870 "route updates are not being sent out and OutQ stuck" - I
now have exactly that problem. Had to downgrade to 0.99.24.1 to have it
working again.

Matthias
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