import bgp ipv6 routes issue

[Alexander Zubkov]

Hi,

Looks like you have the same AS on your peers. So they have iBGP
sessions. And those keep the next hop attribute by default.

On Wed, Jul 22, 2020 at 12:55 PM Mazur, Dariusz <dmazur at akamai.com> wrote:
>
> Hello Bird Users,
>
> Hope you will be able to help me. I have 8  bgp peers which use  the same bgp template with below import filter:
>
>
>
> filter IMPORT__SPINE__TO__LEAF
>
> {
>
>     bgp_community.add(LOOP_DETECTION);
>
>     gw = bgp_next_hop;  -> I use it to set ipv6 bgp next hop to global ipv6 address  (not link local)
>
>     if (net = 0.0.0.0/0 || net = ::/0) then
>
>     {
>
>         reject;
>
>     }
>
>    …
>
>     else
>
>     {
>
>         reject;
>
>     }
>
> }
>
>
>
> 1.First Peer  -> this look good
>
>
>
> r14.spine101.fra02.fab> bird show protocols all 2a02:26f0:3700:1101::1__r01.leaf101
>
> BIRD 2.0.7 ready.
>
> Name       Proto      Table      State  Since         Info
>
> 2a02:26f0:3700:1101::1__r01.leaf101 BGP        ---        up     09:58:55.848  Established
>
> …
>
> Channel ipv6
>
>     State:          UP
>
>     Table:          master6
>
>     Preference:     100
>
>     Input filter:   IMPORT__SPINE__TO__LEAF
>
>     Output filter:  EXPORT__SPINE__TO__LEAF
>
>     Routes:         27 imported, 4 exported, 25 preferred   -> I expect to import 27 routes
>
>     Route change stats:     received   rejected   filtered    ignored   accepted
>
>       Import updates:             27          0          0          0         27
>
>       Import withdraws:            0          0        ---          0          0
>
>       Export updates:          15846         50      15791        ---          5
>
>       Export withdraws:           11        ---        ---        ---          0
>
>     BGP Next hop:   2a02:26f0:3700:1101::
>
>
>
> 2.Second Peer -> this does not look good:
>
>
>
> r14.spine101.fra02.fab> bird show protocols all 2a02:26f0:3700:1102::1__r02.leaf101
>
> BIRD 2.0.7 ready.
>
> Name       Proto      Table      State  Since         Info
>
> 2a02:26f0:3700:1102::1__r02.leaf101 BGP        ---        up     09:58:56.676  Established
>
>
>
>   Channel ipv6
>
>     State:          UP
>
>     Table:          master6
>
>     Preference:     100
>
>     Input filter:   IMPORT__SPINE__TO__LEAF
>
>     Output filter:  EXPORT__SPINE__TO__LEAF
>
>     Routes:         4 imported, 4 exported, 0 preferred  -> bird imports  only 4 routes
>
>     Route change stats:     received   rejected   filtered    ignored   accepted
>
>       Import updates:             27          0                             23          0          4       -> bird reject 23 routes
>
>
>
> After I reload this protocol all looks good and bird import 27 routes
>
>
>
> In logs I see  “Invalid gw address”,  therefore I suspect issue with “gw = bgp_next_hop”
>
>
>
> 2020-07-22 09:58:56.801 <ERR> filters, line 169: Invalid gw address
>
> 2020-07-22 09:58:56.801 <ERR> filters, line 169: Invalid gw address
>
> 2020-07-22 09:58:56.801 <ERR> filters, line 169: Invalid gw address
>
> 2020-07-22 09:58:56.801 <ERR> filters, line 169: Invalid gw address
>
> 2020-07-22 09:58:56.801 <ERR> filters, line 169: Invalid gw address
>
>
>
> I am able to reproduce issue on more routers, please find below out from another router:
>
> r16.spine101.fra02.fab> show bgp summary  ->  it parse “show protocols all”
>
>
>
> IPv6 Peers: 10 Down: 0
>
> Peer                          AS      State       (Im/Filt/Exp/Pref)        Up/Down         Protocol
>
> 2a02:26f0:3700:211::          20940   Established (8480/0/35/8480)          00:36:46        2a02:26f0:3700:211::__r01.border101
>
> 2a02:26f0:3700:311::          20940   Established (7131/0/34/7)             00:36:48        2a02:26f0:3700:311::__r02.border101
>
> 2a02:26f0:3700:1301::1        20940   Established (28/0/4/26)               00:36:51        2a02:26f0:3700:1301::1__r01.leaf101
>
> 2a02:26f0:3700:1302::1        20940   Established (4/0/4/0)                 00:36:49        2a02:26f0:3700:1302::1__r02.leaf101  -> 4 routes are imported but should be 28
>
> 2a02:26f0:3700:1303::1        20940   Established (28/0/4/1)                00:36:53        2a02:26f0:3700:1303::1__r03.leaf101
>
> 2a02:26f0:3700:1304::1        20940   Established (4/0/4/0)                 00:36:50        2a02:26f0:3700:1304::1__r04.leaf101
>
> 2a02:26f0:3700:1305::1        20940   Established (28/0/4/1)                00:36:47        2a02:26f0:3700:1305::1__r05.leaf101
>
> 2a02:26f0:3700:1306::1        20940   Established (28/0/4/1)                00:36:46        2a02:26f0:3700:1306::1__r06.leaf101
>
> 2a02:26f0:3700:1307::1        20940   Established (28/0/4/1)                00:36:47        2a02:26f0:3700:1307::1__r07.leaf101
>
> 2a02:26f0:3700:1308::1        20940   Established (28/0/4/1)                00:36:46        2a02:26f0:3700:1308::1__r08.leaf101
>
>
>
> After protocol reload all looks good.
>
>
>
> Did you face similar problem?
>
>
>
> Regards,
>
> Dariusz
>
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