Enable BFD for Static Route for chassis-packet. (sonic-net#15383)

*What I did:
Enable BFD for Static Route for chassis-packet. This will trigger the use of the feature as defined in here: sonic-net#13789

Signed-off-by: Abhishek Dosi <abdosi@microsoft.com>

src/sonic-config-engine/minigraph.py

@@ -1986,6 +1986,10 @@ def parse_xml(filename, platform=None, port_config_file=None, asic_name=None, hw
  port['mux_cable'] = "true"
 
  if static_routes:
+ # Enable static Route BFD by default for static route in chassis-packet
+ if switch_type == "chassis-packet":
+ for pfx, data in static_routes.items():
+ data.update({"bfd":"true"})
  results['STATIC_ROUTE'] = static_routes
 
  for nghbr in list(neighbors.keys()):

src/sonic-config-engine/tests/test_cfggen.py

@@ -1029,14 +1029,14 @@ def test_minigraph_bgp_packet_chassis_static_route(self):
  output = self.run_script(argument)
  self.assertEqual(
  utils.to_dict(output.strip()),
- utils.to_dict("{'8.0.0.1/32': {'nexthop': '192.168.1.2,192.168.2.2', 'ifname': 'PortChannel40,PortChannel50', 'advertise':'false'}}")
+ utils.to_dict("{'8.0.0.1/32': {'nexthop': '192.168.1.2,192.168.2.2', 'ifname': 'PortChannel40,PortChannel50', 'advertise':'false', 'bfd':'true'}}")
  )
 
  argument = ['-m', self.packet_chassis_graph, '-p', self.packet_chassis_port_ini, '-n', "asic1", '-v', "STATIC_ROUTE"]
  output = self.run_script(argument)
  self.assertEqual(
  utils.to_dict(output.strip()),
- utils.to_dict("{'8.0.0.1/32': {'nexthop': '192.168.1.2,192.168.2.2', 'ifname': 'PortChannel40,PortChannel50', 'advertise':'false'}}")
+ utils.to_dict("{'8.0.0.1/32': {'nexthop': '192.168.1.2,192.168.2.2', 'ifname': 'PortChannel40,PortChannel50', 'advertise':'false', 'bfd':'true'}}")
  )
 
  def test_minigraph_bgp_packet_chassis_vlan_subintf(self):

src/sonic-yang-models/yang-models/sonic-static-route.yang

@@ -54,6 +54,12 @@ module sonic-static-route {
  }
  default "false";
  }
+ leaf bfd {
+ type string {
+ pattern "((true|false),)*(true|false)";
+ }
+ default "false";
+ }
  }
  list STATIC_ROUTE_LIST {
  key "vrf_name prefix";