In T132 adding the "set src" command to a route-map was added. however so far it's not possible to set it for the bgp protocol (neither for ipv4 nor ipv6).
foo@bar# set protocols static Possible completions: (...) route-map Filter routes installed in local route map
foo@bar# set protocols bgp Possible completions: > <1-4294967294> AS number > 64500
foo@bar# set protocols bgp 64500 Possible completions: > address-family BGP address-family parameters > maximum-paths BGP multipaths +> neighbor BGP neighbor > parameters BGP parameters +> peer-group BGP peer-group > timers BGP protocol timers
It's possible to set it directly via vtysh:
bar# conf t bar(config)# ip protocol any bgp eigrp kernel openfabric rip static vnc babel connected isis nhrp ospf sharp table bar(config)# ip protocol bgp route-map RM4-SET-SRC
The possibility to set this FRR config from vyos should be added.