lib, zebra: support label chunk requests for SRGB

For SRGB, we need to support chunk requests starting at a
specific point in the label space, rather than just asking
for any sufficiently large chunk. To this purpose, we extend
the label manager api to request a chunk with a base value;
if the base is set to 0, the label manager will behave as it
currently does, i.e. fetching the first free chunk big enough
to satisfy the request.

update all the existing calls to get chunks from the label
manager so that they use MPLS_LABEL_BASE_ANY as the base
for the requested chunk

Signed-off-by: Emanuele Di Pascale <emanuele@voltanet.io>

3 files changed, 11 insertions, 8 deletions

diff --git a/lib/mpls.h b/lib/mpls.h
index b140c8e31..d7b56c47b 100644
--- a/lib/mpls.h
+++ b/lib/mpls.h
@@ -54,6 +54,7 @@ extern "C" {
 #define MPLS_LABEL_RESERVED_MAX            15
 #define MPLS_LABEL_UNRESERVED_MIN          16
 #define MPLS_LABEL_UNRESERVED_MAX          1048575
+#define MPLS_LABEL_BASE_ANY                0
 
 /* Default min and max SRGB label range */
 /* Even if the SRGB allows to manage different Label space between routers,
diff --git a/lib/zclient.c b/lib/zclient.c
index e9b4f5a58..c02ae5d0e 100644
--- a/lib/zclient.c
+++ b/lib/zclient.c
@@ -1995,10 +1995,11 @@ int lm_label_manager_connect(struct zclient *zclient, int async)
  * @param zclient Zclient used to connect to label manager (zebra)
  * @param keep Avoid garbage collection
  * @param chunk_size Amount of labels requested
+ * @param base Base for the label chunk. if MPLS_LABEL_BASE_ANY we do not care
  * @result 0 on success, -1 otherwise
  */
 int zclient_send_get_label_chunk(struct zclient *zclient, uint8_t keep,
-				 uint32_t chunk_size)
+				 uint32_t chunk_size, uint32_t base)
 {
 	struct stream *s;
 
@@ -2018,6 +2019,7 @@ int zclient_send_get_label_chunk(struct zclient *zclient, uint8_t keep,
 	stream_putw(s, zclient->instance);
 	stream_putc(s, keep);
 	stream_putl(s, chunk_size);
+	stream_putl(s, base);
 
 	/* Put length at the first point of the stream. */
 	stream_putw_at(s, 0, stream_get_endp(s));
@@ -2038,7 +2040,7 @@ int zclient_send_get_label_chunk(struct zclient *zclient, uint8_t keep,
  * @param end To write last assigned chunk label to
  * @result 0 on success, -1 otherwise
  */
-int lm_get_label_chunk(struct zclient *zclient, uint8_t keep,
+int lm_get_label_chunk(struct zclient *zclient, uint8_t keep, uint32_t base,
 		       uint32_t chunk_size, uint32_t *start, uint32_t *end)
 {
 	int ret;
@@ -2063,6 +2065,8 @@ int lm_get_label_chunk(struct zclient *zclient, uint8_t keep,
 	stream_putc(s, keep);
 	/* chunk size */
 	stream_putl(s, chunk_size);
+	/* requested chunk base */
+	stream_putl(s, base);
 	/* Put length at the first point of the stream. */
 	stream_putw_at(s, 0, stream_get_endp(s));
 
diff --git a/lib/zclient.h b/lib/zclient.h
index d65173868..be2ef69dc 100644
--- a/lib/zclient.h
+++ b/lib/zclient.h
@@ -609,15 +609,13 @@ extern struct interface *zebra_interface_link_params_read(struct stream *s,
 							  vrf_id_t vrf_id);
 extern size_t zebra_interface_link_params_write(struct stream *,
 						struct interface *);
-extern int zclient_send_get_label_chunk(
-	struct zclient	*zclient,
-	uint8_t		keep,
-	uint32_t	chunk_size);
+extern int zclient_send_get_label_chunk(struct zclient *zclient, uint8_t keep,
+					uint32_t chunk_size, uint32_t base);
 
 extern int lm_label_manager_connect(struct zclient *zclient, int async);
 extern int lm_get_label_chunk(struct zclient *zclient, uint8_t keep,
-			      uint32_t chunk_size, uint32_t *start,
-			      uint32_t *end);
+			      uint32_t base, uint32_t chunk_size,
+			      uint32_t *start, uint32_t *end);
 extern int lm_release_label_chunk(struct zclient *zclient, uint32_t start,
 				  uint32_t end);
 extern int tm_table_manager_connect(struct zclient *zclient);