zebra: add a runtime flag to enable vrf with netns

The netns backend is chosen by VRF if a runtime flag named vrfwnetns is
selected when running zebra.
In the case the NETNS backend is chosen, in some case the VRFID value is
being assigned the value of the NSID. Within the perimeter of that work,
this is why the vrf_lookup_by_table function is extended with a new
parameter.

Signed-off-by: Philippe Guibert <philippe.guibert@6wind.com>

3 files changed, 27 insertions, 2 deletions

diff --git a/lib/ns.c b/lib/ns.c
index 0b2a3bec7..e3a1d9d0d 100644
--- a/lib/ns.c
+++ b/lib/ns.c
@@ -378,7 +378,9 @@ static int ns_config_write(struct vty *vty)
 	struct ns *ns;
 	int write = 0;
 
-	RB_FOREACH (ns, ns_head, &ns_tree) {
+	if (vrf_is_backend_netns())
+		return 0;
+	RB_FOREACH(ns, ns_head, &ns_tree) {
 		if (ns->ns_id == NS_DEFAULT || ns->name == NULL)
 			continue;
 
@@ -411,7 +413,7 @@ void ns_init(void)
 		exit(1);
 	}
 
-	if (have_netns()) {
+	if (have_netns() && !vrf_is_backend_netns()) {
 		/* Install NS commands. */
 		install_node(&ns_node, ns_config_write);
 		install_element(CONFIG_NODE, &ns_netns_cmd);
diff --git a/lib/vrf.c b/lib/vrf.c
index 02946df2b..c300a87a3 100644
--- a/lib/vrf.c
+++ b/lib/vrf.c
@@ -44,6 +44,8 @@ RB_GENERATE(vrf_name_head, vrf, name_entry, vrf_name_compare);
 struct vrf_id_head vrfs_by_id = RB_INITIALIZER(&vrfs_by_id);
 struct vrf_name_head vrfs_by_name = RB_INITIALIZER(&vrfs_by_name);
 
+static int vrf_backend;
+
 /*
  * Turn on/off debug code
  * for vrf.
@@ -446,6 +448,21 @@ int vrf_socket(int domain, int type, int protocol, vrf_id_t vrf_id)
 	return ret;
 }
 
+int vrf_is_backend_netns(void)
+{
+	return (vrf_backend == VRF_BACKEND_NETNS);
+}
+
+int vrf_get_backend(void)
+{
+	return vrf_backend;
+}
+
+void vrf_configure_backend(int vrf_backend_netns)
+{
+	vrf_backend = vrf_backend_netns;
+}
+
 /* vrf CLI commands */
 DEFUN_NOSH (vrf,
        vrf_cmd,
diff --git a/lib/vrf.h b/lib/vrf.h
index 99c048c70..f1dc45019 100644
--- a/lib/vrf.h
+++ b/lib/vrf.h
@@ -96,6 +96,9 @@ RB_HEAD(vrf_name_head, vrf);
 RB_PROTOTYPE(vrf_name_head, vrf, name_entry, vrf_name_compare)
 DECLARE_QOBJ_TYPE(vrf)
 
+/* Allow VRF with netns as backend */
+#define VRF_BACKEND_VRF_LITE 0
+#define VRF_BACKEND_NETNS    1
 
 extern struct vrf_id_head vrfs_by_id;
 extern struct vrf_name_head vrfs_by_name;
@@ -203,6 +206,9 @@ extern void vrf_cmd_init(int (*writefunc)(struct vty *vty));
 
 /* Create a socket serving for the given VRF */
 extern int vrf_socket(int, int, int, vrf_id_t);
+extern void vrf_configure_backend(int vrf_backend_netns);
+extern int vrf_get_backend(void);
+extern int vrf_is_backend_netns(void);
 
 /*
  * VRF Debugging