zebra, ifp: on netlink discovery, anticipate the vrf creation

there may be cases where the vrf is yet allocated from the vty, and the
discovery process did not make the relationship between the vrf_id and
the name of the vrf. For instance, by parsing an interface belonging to
vrf-id X, it is not sure that vrf-id X and vrfname XX are talking about
the same vrf. For that, lets allocate the vrf, and lets try to detect
there is a duplicate case in vrf, so that the merge can be done without
any impact for the user.

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

2 files changed, 20 insertions, 0 deletions

diff --git a/lib/if.c b/lib/if.c
index 0cfd59116..a80375437 100644
--- a/lib/if.c
+++ b/lib/if.c
@@ -177,6 +177,8 @@ void if_update_to_new_vrf(struct interface *ifp, vrf_id_t vrf_id)
 	if (ifp->ifindex != IFINDEX_INTERNAL)
 		IFINDEX_RB_INSERT(vrf, ifp);
 
+	if (!old_vrf->name)
+		return;
 	/*
 	 * HACK: Change the interface VRF in the running configuration directly,
 	 * bypassing the northbound layer. This is necessary to avoid deleting
diff --git a/lib/vrf.c b/lib/vrf.c
index 229f19f29..862a3da06 100644
--- a/lib/vrf.c
+++ b/lib/vrf.c
@@ -176,6 +176,24 @@ struct vrf *vrf_get(vrf_id_t vrf_id, const char *name)
 			   name, vrf_id, vrf->vrf_id);
 		return NULL;
 	}
+	/* look for duplicates. case is followine one:
+	 * - a vrf is configured per name -> vrfA
+	 * - netlink discovery creates a vrf with vrf_id ->vrfB
+	 * - then, netlink discovers vrf, and associated vrf_id and name
+	 * -> so vrfA and vrfB must be merged
+	 */
+	if (vrf && vrf_id != VRF_UNKNOWN
+	    && vrf->vrf_id == VRF_UNKNOWN) {
+		struct vrf *vrf2 = vrf_lookup_by_id(vrf_id);
+		struct interface *ifp;
+
+		if (vrf2 && !vrf2->name && vrf2 != vrf) {
+			/* move vrf2 context to vrf */
+			FOR_ALL_INTERFACES (vrf2, ifp)
+				if_update_to_new_vrf(ifp, vrf);
+			vrf_delete(vrf2);
+		}
+	}
 	/* Try to find VRF both by ID and name */
 	if (!vrf && vrf_id != VRF_UNKNOWN)
 		vrf = vrf_lookup_by_id(vrf_id);