zebra: add label chunk allocation in the dynamic block range

This commit adds support for the label chunk allocation in
the configured dynamic block range.

An additional check ensures the upper bound does not go
over the upper bound of the dynamic-block.
Otherwise, a chunk is created with the lower bound set
to the first label element available in the defined
range.

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

diff --git a/zebra/label_manager.c b/zebra/label_manager.c
index bb722f4313d59bd42c7ff7f6a8b1a78b99c3d91b..24968f6509a89504ddf661a570db950df2764293 100644 (file)
--- a/zebra/label_manager.c
+++ b/zebra/label_manager.c
@@ -400,6 +400,7 @@ assign_label_chunk(uint8_t proto, unsigned short instance, uint32_t session_id,
        struct label_manager_chunk *lmc;
        struct listnode *node;
        uint32_t prev_end = lbl_mgr.dynamic_block_start - 1;
+       struct label_manager_chunk *lmc_block_last = NULL;
 
        /* handle chunks request with a specific base label
         * - static label requests: BGP hardset value, Pathd
@@ -416,7 +417,9 @@ assign_label_chunk(uint8_t proto, unsigned short instance, uint32_t session_id,
        for (ALL_LIST_ELEMENTS_RO(lbl_mgr.lc_list, node, lmc)) {
                if (lmc->start <= prev_end)
                        continue;
-               if (lmc->proto == NO_PROTO && lmc->end - lmc->start + 1 == size) {
+               if (lmc->proto == NO_PROTO &&
+                   lmc->end - lmc->start + 1 == size &&
+                   lmc->end <= lbl_mgr.dynamic_block_end) {
                        lmc->proto = proto;
                        lmc->instance = instance;
                        lmc->session_id = session_id;
@@ -426,7 +429,8 @@ assign_label_chunk(uint8_t proto, unsigned short instance, uint32_t session_id,
                }
                /* check if we hadve a "hole" behind us that we can squeeze into
                 */
-               if (lmc->start - prev_end > size) {
+               if (lmc->start - prev_end > size &&
+                   prev_end + 1 + size <= lbl_mgr.dynamic_block_end) {
                        lmc = create_label_chunk(proto, instance, session_id,
                                                 keep, prev_end + 1,
                                                 prev_end + size, true);
@@ -434,17 +438,19 @@ assign_label_chunk(uint8_t proto, unsigned short instance, uint32_t session_id,
                        return lmc;
                }
                prev_end = lmc->end;
+
+               /* check if we have a chunk that goes over the end block */
+               if (lmc->end > lbl_mgr.dynamic_block_end)
+                       continue;
+               lmc_block_last = lmc;
        }
        /* otherwise create a new one */
        uint32_t start_free;
 
-       if (list_isempty(lbl_mgr.lc_list))
+       if (lmc_block_last == NULL)
                start_free = lbl_mgr.dynamic_block_start;
        else
-               start_free = ((struct label_manager_chunk *)listgetdata(
-                                     listtail(lbl_mgr.lc_list)))
-                                    ->end
-                            + 1;
+               start_free = lmc_block_last->end + 1;
 
        if (start_free > lbl_mgr.dynamic_block_end - size + 1) {
                flog_err(EC_ZEBRA_LM_EXHAUSTED_LABELS,