lib, zebra: Add new api to specify a label associated with the vrf

For L3VPN's we need to create a label associated with the specified
vrf to be installed into the kernel to allow a pop and lookup
operation.

The new api is:
zclient_send_vrf_label(struct zclient *zclient, vrf_id_t vrf_id,
                       mpls_label_t label);

For the specified vrf_id associate the specified label for
a pop and lookup operation for forwarding.

To setup a POP and Forward use MPLS_LABEL_IMPLICIT_NULL
If the same label is passed in we ignore the call.
If the label is different we update entry.
If the label is MPLS_LABEL_NONE we remove
the entry.

This sets up the api.  Future commits will have the functionality
to actually install into the kernel.

Signed-off-by: Donald Sharp <sharpd@cumulusnetworks.com>

1 files changed, 48 insertions, 0 deletions

diff --git a/zebra/zserv.c b/zebra/zserv.c
index 9da8d593e..5f2757f52 100644
--- a/zebra/zserv.c
+++ b/zebra/zserv.c
@@ -2486,6 +2486,51 @@ stream_failure:
 	return 1;
 }
 
+static void zread_vrf_label(struct zserv *client,
+			    struct zebra_vrf *zvrf)
+{
+	struct interface *ifp;
+	mpls_label_t nlabel;
+	struct stream *s;
+	struct zebra_vrf *def_zvrf;
+
+	s = client->ibuf;
+	STREAM_GETL(s, nlabel);
+
+	if (nlabel == zvrf->label) {
+		/*
+		 * Nothing to do here move along
+		 */
+		return;
+	}
+
+	if (zvrf->vrf->vrf_id != VRF_DEFAULT)
+		ifp = if_lookup_by_name(zvrf->vrf->name, zvrf->vrf->vrf_id);
+	else
+		ifp = if_lookup_by_name("lo", VRF_DEFAULT);
+
+	if (!ifp) {
+		zlog_debug("Unable to find specified Interface for %s",
+			   zvrf->vrf->name);
+		return;
+	}
+
+	def_zvrf = zebra_vrf_lookup_by_id(VRF_DEFAULT);
+
+	if (zvrf->label != MPLS_LABEL_IPV4NULL)
+		mpls_lsp_uninstall(def_zvrf, ZEBRA_LSP_STATIC,
+				   zvrf->label, NEXTHOP_TYPE_IFINDEX,
+				   NULL, ifp->ifindex);
+
+	if (nlabel != MPLS_LABEL_IPV4NULL)
+		mpls_lsp_install(def_zvrf, ZEBRA_LSP_STATIC, nlabel,
+				 MPLS_LABEL_IMPLICIT_NULL, NEXTHOP_TYPE_IFINDEX, NULL, ifp->ifindex);
+
+	zvrf->label = nlabel;
+stream_failure:
+	return;
+}
+
 static inline void zserv_handle_commands(struct zserv *client,
 					 uint16_t command,
 					 uint16_t length,
@@ -2570,6 +2615,9 @@ static inline void zserv_handle_commands(struct zserv *client,
 	case ZEBRA_VRF_UNREGISTER:
 		zread_vrf_unregister(client, length, zvrf);
 		break;
+	case ZEBRA_VRF_LABEL:
+		zread_vrf_label(client, zvrf);
+		break;
 	case ZEBRA_BFD_CLIENT_REGISTER:
 		zebra_ptm_bfd_client_register(client, length);
 		break;