tests: Add topotest for RIB/FIB feature

Signed-off-by: Yuqing Zhao <galadriel.zyq@alibaba-inc.com>

Author: GaladrielZhao

tests/topotests/zebra_nhg_fib/r1/frr.conf

@@ -0,0 +1,19 @@
+hostname r1
+log file /tmp/r1-zebra.log debug
+!
+interface r1-eth0
+ ip address 10.0.0.1/24
+!
+ip route 192.168.1.0/24 Null0
+!
+router bgp 65001
+ bgp router-id 10.255.255.1
+ no bgp ebgp-requires-policy
+ neighbor 10.0.0.2 remote-as 65002
+ address-family ipv4 unicast
+  network 192.168.1.0/24
+ !
+!
+line vty
+!
+end

tests/topotests/zebra_nhg_fib/r2/frr.conf

@@ -0,0 +1,14 @@
+hostname r2
+log file /tmp/r2-zebra.log debug
+!
+interface r2-eth0
+ ip address 10.0.0.2/24
+!
+router bgp 65002
+ bgp router-id 10.255.255.2
+ no bgp ebgp-requires-policy
+ neighbor 10.0.0.1 remote-as 65001
+!
+line vty
+!
+end