Useful to have it for datacenter profile only, disabled for traditional.
If the peer is not established or established, but has no description set,
we will show the FRR version instead, which is kinda handy to have instead of
nothing.
Signed-off-by: Donatas Abraitis <donatas@opensourcerouting.org>
Implement: https://datatracker.ietf.org/doc/html/draft-abraitis-bgp-version-capability
Tested with GoBGP:
```
% ./gobgp neighbor 192.168.10.124
BGP neighbor is 192.168.10.124, remote AS 65001
BGP version 4, remote router ID 200.200.200.202
BGP state = ESTABLISHED, up for 00:01:49
BGP OutQ = 0, Flops = 0
Hold time is 3, keepalive interval is 1 seconds
Configured hold time is 90, keepalive interval is 30 seconds
Neighbor capabilities:
multiprotocol:
ipv4-unicast: advertised and received
ipv6-unicast: advertised
route-refresh: advertised and received
extended-nexthop: advertised
Local: nlri: ipv4-unicast, nexthop: ipv6
UnknownCapability(6): received
UnknownCapability(9): received
graceful-restart: advertised and received
Local: restart time 10 sec
ipv6-unicast
ipv4-unicast
Remote: restart time 120 sec, notification flag set
ipv4-unicast, forward flag set
4-octet-as: advertised and received
add-path: received
Remote:
ipv4-unicast: receive
enhanced-route-refresh: received
long-lived-graceful-restart: advertised and received
Local:
ipv6-unicast, restart time 10 sec
ipv4-unicast, restart time 20 sec
Remote:
ipv4-unicast, restart time 0 sec, forward flag set
fqdn: advertised and received
Local:
name: donatas-pc, domain:
Remote:
name: spine1-debian-11, domain:
software-version: advertised and received
Local:
GoBGP/3.10.0
Remote:
FRRouting/8.5-dev-MyOwnFRRVersion-gdc92f44a45-dirt
cisco-route-refresh: received
Message statistics:
```
FRR side:
```
root@spine1-debian-11:~# vtysh -c 'show bgp neighbor 192.168.10.17 json' | \
> jq '."192.168.10.17".neighborCapabilities.softwareVersion.receivedSoftwareVersion'
"GoBGP/3.10.0"
root@spine1-debian-11:~#
```
Signed-off-by: Donatas Abraitis <donatas@opensourcerouting.org>
