zebra: rework dynamic label request algorithm

The label chunk algorithm needs to be revisited to support a
configured dynamic-block or the default one.

Reuse the 'lbl_mgr.dynamic_block_[start/end]' variables,
whereever needed, and simplify the algorithm.

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

diff --git a/zebra/label_manager.c b/zebra/label_manager.c
index 3fc1ee5bae8b08202d2f51debfe7b6bffbb282f4..bb722f4313d59bd42c7ff7f6a8b1a78b99c3d91b 100644 (file)
--- a/zebra/label_manager.c
+++ b/zebra/label_manager.c
@@ -399,7 +399,7 @@ 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 = MPLS_LABEL_UNRESERVED_MIN - 1;
+       uint32_t prev_end = lbl_mgr.dynamic_block_start - 1;
 
        /* handle chunks request with a specific base label
         * - static label requests: BGP hardset value, Pathd
@@ -414,8 +414,9 @@ assign_label_chunk(uint8_t proto, unsigned short instance, uint32_t session_id,
 
        /* first check if there's one available */
        for (ALL_LIST_ELEMENTS_RO(lbl_mgr.lc_list, node, lmc)) {
-               if (lmc->proto == NO_PROTO
-                   && lmc->end - lmc->start + 1 == size) {
+               if (lmc->start <= prev_end)
+                       continue;
+               if (lmc->proto == NO_PROTO && lmc->end - lmc->start + 1 == size) {
                        lmc->proto = proto;
                        lmc->instance = instance;
                        lmc->session_id = session_id;
@@ -425,7 +426,7 @@ 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) && (lmc->start - prev_end > size)) {
+               if (lmc->start - prev_end > size) {
                        lmc = create_label_chunk(proto, instance, session_id,
                                                 keep, prev_end + 1,
                                                 prev_end + size, true);
@@ -438,14 +439,14 @@ assign_label_chunk(uint8_t proto, unsigned short instance, uint32_t session_id,
        uint32_t start_free;
 
        if (list_isempty(lbl_mgr.lc_list))
-               start_free = MPLS_LABEL_UNRESERVED_MIN;
+               start_free = lbl_mgr.dynamic_block_start;
        else
                start_free = ((struct label_manager_chunk *)listgetdata(
                                      listtail(lbl_mgr.lc_list)))
                                     ->end
                             + 1;
 
-       if (start_free > MPLS_LABEL_UNRESERVED_MAX - size + 1) {
+       if (start_free > lbl_mgr.dynamic_block_end - size + 1) {
                flog_err(EC_ZEBRA_LM_EXHAUSTED_LABELS,
                         "Reached max labels. Start: %u, size: %u", start_free,
                         size);