master mpls changes break non MPLS UNICAST SAFI label distribution

[louberger]

Breaks VPN SAFI for at least the implicit label (3) case -- which is used for tunnel control with ENCAP SAFI/Attribute. Based on code review, expect that EVPN label distribution is also broken.

[louberger]

To test: Bring up two bgp neighbors with both v4 and v6 neighbors activated, i.e., under:
address-family ipv4 vpn
and
address-family ipv6 vpn

Simple test 1: v4 vpn route with label
enter configure
configure bgp
add:
address-family ipv4 vpn
network 1.1.1.1/24 rd 1.1.1.1:1 tag 1000
^Z
Check on local:
'H192.1.1.1# show bgp ipv4 vpn
BGP table version is 0, local router ID is 192.1.1.1
Status codes: s suppressed, d damped, h history, * valid, > best, i - internal
Origin codes: i - IGP, e - EGP, ? - incomplete

Network Next Hop Metric LocPrf Weight Path
Route Distinguisher: 1.1.1.1:1
*> 1.1.1.0/24 :: 0 32768 i
UN=:: label=1000 type=bgp, subtype=1

Displayed 1 routes and 1 total paths
Check on peer:H192.1.1.2> show bgp ipv4 vpn
BGP table version is 0, local router ID is 192.1.1.2
Status codes: s suppressed, d damped, h history, * valid, > best, i - internal
Origin codes: i - IGP, e - EGP, ? - incomplete

Network Next Hop Metric LocPrf Weight Path
Route Distinguisher: 1.1.1.1:1
*>i1.1.1.0/24 :: 0 100 0 i
UN=:: label=1000 type=bgp, subtype=0

Displayed 1 routes and 1 total paths

Note label value

[louberger]

More complex test uses to RR clients and 1 RR: BGP1<-->RR<-->BGP2

Repeat addition of single label on BGP1 and check that it propagates to BGP2

[pguibert6WIND]

about EVPN setup to share, some more work is needed to make evpn work and be available to troubleshoot label:

• fix Transmitted EVPN packets do not contain nexthop attribute #498
• show bgp l2vpn evpn should display the label value ( which is not the case yet)

however, below you can find a dut/router config setup
router bgp 7675
bgp router-id 10.125.0.1
neighbor 10.125.0.2 remote-as 7675
!
address-family l2vpn evpn
network 10.100.0.0/24 rd 603:1 ethtag 425 label 544 esi 00:11:22:33:44:55:66:77:88:99 gwip 0.0.0.0 routermac 00:01:02:03:04:05
neighbor 10.125.0.2 activate
exit-address-family

=================================

[louberger]

VPN and ENCAP safis are working on master.