zapi: add support for routes with multiple labels

This will be necessary for the Segment Routing feature.

Signed-off-by: Renato Westphal <renato@opensourcerouting.org>

5 files changed, 44 insertions, 13 deletions

diff --git a/lib/mpls.h b/lib/mpls.h
index 025770d47..bf98eecd8 100644
--- a/lib/mpls.h
+++ b/lib/mpls.h
@@ -44,6 +44,9 @@
 #define MPLS_DEFAULT_MIN_SRGB_LABEL        16000
 #define MPLS_DEFAULT_MAX_SRGB_LABEL        23999
 
+/* Maximum # labels that can be pushed. */
+#define MPLS_MAX_LABELS                    16
+
 #define IS_MPLS_RESERVED_LABEL(label)                                          \
 	(label >= MPLS_MIN_RESERVED_LABEL && label <= MPLS_MAX_RESERVED_LABEL)
 
diff --git a/lib/zclient.c b/lib/zclient.c
index 3f5c7a0f6..e063c7151 100644
--- a/lib/zclient.c
+++ b/lib/zclient.c
@@ -970,10 +970,26 @@ int zapi_route_encode(u_char cmd, struct stream *s, struct zapi_route *api)
 				break;
 			}
 
-			/* For labeled-unicast, each nexthop is followed
-			 * by label. */
-			if (CHECK_FLAG(api->message, ZAPI_MESSAGE_LABEL))
-				stream_putl(s, api_nh->label);
+			/* MPLS labels for BGP-LU or Segment Routing */
+			if (CHECK_FLAG(api->message, ZAPI_MESSAGE_LABEL)) {
+				if (api_nh->label_num > MPLS_MAX_LABELS) {
+					char buf[PREFIX2STR_BUFFER];
+					prefix2str(&api->prefix, buf,
+						   sizeof(buf));
+					zlog_err(
+						"%s: prefix %s: can't encode "
+						"%u labels (maximum is %u)",
+						__func__, buf,
+						api_nh->label_num,
+						MPLS_MAX_LABELS);
+					return -1;
+				}
+
+				stream_putc(s, api_nh->label_num);
+				stream_put(s, &api_nh->labels[0],
+					   api_nh->label_num
+						   * sizeof(mpls_label_t));
+			}
 		}
 	}
 
@@ -1064,11 +1080,21 @@ int zapi_route_decode(struct stream *s, struct zapi_route *api)
 				break;
 			}
 
-			/* For labeled-unicast, each nexthop is followed
-			 * by label. */
+			/* MPLS labels for BGP-LU or Segment Routing */
 			if (CHECK_FLAG(api->message, ZAPI_MESSAGE_LABEL)) {
-				stream_get(&api_nh->label, s,
-					   sizeof(api_nh->label));
+				api_nh->label_num = stream_getc(s);
+
+				if (api_nh->label_num > MPLS_MAX_LABELS) {
+					zlog_warn(
+						"%s: invalid number of MPLS "
+						"labels (%u)",
+						__func__, api_nh->label_num);
+					return -1;
+				}
+
+				stream_get(&api_nh->labels[0], s,
+					   api_nh->label_num
+						   * sizeof(mpls_label_t));
 			}
 		}
 	}
diff --git a/lib/zclient.h b/lib/zclient.h
index 2e450ed39..40ddbf62d 100644
--- a/lib/zclient.h
+++ b/lib/zclient.h
@@ -230,7 +230,10 @@ struct zapi_nexthop {
 	enum nexthop_types_t type;
 	ifindex_t ifindex;
 	union g_addr gate;
-	mpls_label_t label;
+
+	/* MPLS labels for BGP-LU or Segment Routing */
+	uint8_t label_num;
+	mpls_label_t labels[MPLS_MAX_LABELS];
 };
 
 struct zapi_route {
diff --git a/zebra/zebra_mpls.h b/zebra/zebra_mpls.h
index 6bddc4d00..c8df8670f 100644
--- a/zebra/zebra_mpls.h
+++ b/zebra/zebra_mpls.h
@@ -37,8 +37,6 @@
 
 /* Definitions and macros. */
 
-#define MPLS_MAX_LABELS 16  /* Maximum # labels that can be pushed. */
-
 #define NHLFE_FAMILY(nhlfe)                                                    \
 	(((nhlfe)->nexthop->type == NEXTHOP_TYPE_IPV6                          \
 	  || (nhlfe)->nexthop->type == NEXTHOP_TYPE_IPV6_IFINDEX)              \
diff --git a/zebra/zserv.c b/zebra/zserv.c
index 94e34865b..de475dccf 100644
--- a/zebra/zserv.c
+++ b/zebra/zserv.c
@@ -1222,8 +1222,9 @@ static int zread_route_add(struct zserv *client, u_short length,
 
 				label_type =
 					lsp_type_from_re_type(client->proto);
-				nexthop_add_labels(nexthop, label_type, 1,
-						   &api_nh->label);
+				nexthop_add_labels(nexthop, label_type,
+						   api_nh->label_num,
+						   &api_nh->labels[0]);
 			}
 		}
 	}