bgpd: fix labels in adj-rib-in

In a BGP L3VPN context using ADJ-RIB-IN (ie. enabled with
'soft-reconfiguration inbound'), after applying a deny route-map and
removing it, the remote MPLS label information is lost. As a result, BGP
is unable to re-install the related routes in the RIB.

For example,

> router bgp 65500
> [..]
>  neighbor 192.0.2.2 remote-as 65501
>  address-family ipv4 vpn
>   neighbor 192.0.2.2 activate
>   neighbor 192.0.2.2 soft-reconfiguration inbound

The 192.168.0.0/24 prefix has a remote label value of 102 in the BGP
RIB.

> # show bgp ipv4 vpn 192.168.0.0/24
>  BGP routing table entry for 444:1:192.168.0.0/24, version 2
>  [..]
>      192.168.0.0 from 192.0.2.2
>        Origin incomplete, metric 0, valid, external, best (First path received)
>        Extended Community: RT:52:100
>        Remote label: 102

A route-map now filter all incoming BGP updates:

> route-map rmap deny 1
> router bgp 65500
>  address-family ipv4 vpn
>   neighbor 192.0.2.2 route-map rmap in

The prefix is now filtered:

> # show bgp ipv4 vpn 192.168.0.0/24
> #

The route-map is detached:

> router bgp 65500
>  address-family ipv4 vpn
>   no neighbor 192.168.0.1 route-map rmap in

The BGP RIB entry is present but the remote label is lost:

> # show bgp ipv4 vpn 192.168.0.0/24
>  BGP routing table entry for 444:1:192.168.0.0/24, version 2
>  [..]
>      192.168.0.0 from 192.0.2.2
>        Origin incomplete, metric 0, valid, external, best (First path received)
>        Extended Community: RT:52:100

The reason for the loose is that labels are stored within struct attr ->
struct extra -> struct bgp_labels but not in the struct bgp_adj_in.

Reference the bgp_labels pointer in struct bgp_adj_in and use its values
when doing a soft reconfiguration of the BGP table.

Signed-off-by: Philippe Guibert <philippe.guibert@6wind.com>
Signed-off-by: Louis Scalbert <louis.scalbert@6wind.com>

0 files changed, 0 insertions, 0 deletions