0002-linux-cp-Added-routing-for-prefixes-with-no-paths-av.patch

src/plugins/linux-cp/lcp.c

@@ -161,6 +161,22 @@ lcp_get_netlink_processing_active (void)
   return lcpm->netlink_processing_active;
 }
 
+void
+lcp_set_route_no_paths (u8 is_del)
+{
+  lcp_main_t *lcpm = &lcp_main;
+
+  lcpm->route_no_paths = (is_del != 0);
+}
+
+u8
+lcp_get_route_no_paths (void)
+{
+  lcp_main_t *lcpm = &lcp_main;
+
+  return lcpm->route_no_paths;
+}
+
 /*
  * fd.io coding-style-patch-verification: ON
  *

src/plugins/linux-cp/lcp.h

@@ -31,6 +31,7 @@ typedef struct lcp_main_s
   u8 test_mode;	      /* Set when Unit testing */
   u8 netlink_processing_active; /* Set while a batch of Netlink messages are
 				   being processed */
+  u8 route_no_paths; /* Add routes with no paths as local */
 } lcp_main_t;
 
 extern lcp_main_t lcp_main;
@@ -61,6 +62,12 @@ u8 lcp_get_del_dynamic_on_link_down (void);
 void lcp_set_netlink_processing_active (u8 is_processing);
 u8 lcp_get_netlink_processing_active (void);
 
+/**
+ * Get/Set whether to install routes with no paths as local
+ */
+void lcp_set_route_no_paths (u8 is_del);
+u8 lcp_get_route_no_paths (void);
+
 #endif
 
 /*

src/plugins/linux-cp/lcp_cli.c

@@ -192,6 +192,17 @@ lcp_param_command_fn (vlib_main_t *vm, unformat_input_t *input,
 	    return clib_error_return (0, "unknown input `%U'",
 				      format_unformat_error, line_input);
 	}
+      else if (unformat (line_input, "route-no-paths"))
+	{
+	  if (unformat (line_input, "on") || unformat (line_input, "enable"))
+	    lcp_set_route_no_paths (1 /* is_del */);
+	  else if (unformat (line_input, "off") ||
+		   unformat (line_input, "disable"))
+	    lcp_set_route_no_paths (0 /* is_del */);
+	  else
+	    return clib_error_return (0, "unknown input `%U'",
+				      format_unformat_error, line_input);
+	}
       else
 	return clib_error_return (0, "unknown input `%U'",
 				  format_unformat_error, line_input);
@@ -204,7 +215,8 @@ lcp_param_command_fn (vlib_main_t *vm, unformat_input_t *input,
 VLIB_CLI_COMMAND (lcp_param_command, static) = {
   .path = "lcp param",
   .short_help = "lcp param [del-static-on-link-down (on|enable|off|disable)] "
-		"[del-dynamic-on-link-down (on|enable|off|disable)]",
+		"[del-dynamic-on-link-down (on|enable|off|disable)] "
+		"[route-no-paths (on|enable|off|disable)]",
   .function = lcp_param_command_fn,
 };
 

src/plugins/linux-cp/lcp_interface.c

@@ -138,6 +138,8 @@ lcp_itf_pair_show (u32 phy_sw_if_index)
 		   lcp_get_del_static_on_link_down () ? "on" : "off");
   vlib_cli_output (vm, "lcp del-dynamic-on-link-down %s\n",
 		   lcp_get_del_dynamic_on_link_down () ? "on" : "off");
+  vlib_cli_output (vm, "lcp route-no-paths %s\n",
+		   lcp_get_route_no_paths () ? "on" : "off");
 
   if (phy_sw_if_index == ~0)
     {
@@ -579,6 +581,8 @@ lcp_itf_pair_config (vlib_main_t *vm, unformat_input_t *input)
 	lcp_set_del_static_on_link_down (1 /* is_del */);
       else if (unformat (input, "del-dynamic-on-link-down"))
 	lcp_set_del_dynamic_on_link_down (1 /* is_del */);
+      else if (unformat (input, "route-no-paths"))
+	lcp_set_route_no_paths (1 /* is_del */);
       else
 	return clib_error_return (0, "interfaces not found");
     }

src/plugins/linux-cp/lcp_router.c

@@ -1167,7 +1167,7 @@ lcp_router_route_path_add_special (struct rtnl_route *rr,
 {
   fib_route_path_t *path;
 
-  if (rtnl_route_get_type (rr) < RTN_BLACKHOLE)
+  if (rtnl_route_get_type (rr) < RTN_BLACKHOLE && !(lcp_get_route_no_paths ()))
     return;
 
   /* if it already has a path, it does not need us to add one */
@@ -1176,8 +1176,21 @@ lcp_router_route_path_add_special (struct rtnl_route *rr,
 
   vec_add2 (ctx->paths, path, 1);
 
-  path->frp_flags = FIB_ROUTE_PATH_FLAG_NONE | ctx->type_flags;
-  path->frp_sw_if_index = ~0;
+  /* If there are no paths, and `lcp param route-no-paths` is enabled
+   * we need to add an extra local path. This allows punting traffic
+   * with destinations available only via kernel */
+  if (lcp_get_route_no_paths ())
+    {
+      path->frp_flags = FIB_ROUTE_PATH_LOCAL | ctx->type_flags;
+    } else {
+      path->frp_flags = FIB_ROUTE_PATH_FLAG_NONE | ctx->type_flags;
+    }
+
+  /* Do not add interface to routes from kernel */
+  if (rtnl_route_get_protocol (rr) != RTPROT_KERNEL) {
+    path->frp_sw_if_index = ~0;
+  }
+
   path->frp_proto = fib_proto_to_dpo (ctx->route_proto);
   path->frp_preference = ctx->preference;
 
@@ -1335,7 +1348,7 @@ lcp_router_route_add (struct rtnl_route *rr, int is_replace)
 
   nlt = lcp_router_table_add_or_lock (table_id, pfx.fp_proto);
   /* Skip any kernel routes and IPv6 LL or multicast routes */
-  if (rproto == RTPROT_KERNEL ||
+  if ((rproto == RTPROT_KERNEL && !(lcp_get_route_no_paths ())) ||
       (FIB_PROTOCOL_IP6 == pfx.fp_proto &&
        (ip6_address_is_multicast (&pfx.fp_addr.ip6) ||
 	ip6_address_is_link_local_unicast (&pfx.fp_addr.ip6))))