zebra: Move id counter into zebra_nhg_find()

Move the id counter further up into zebra_nhg_find() so that
it is still incremented if we receive a duplicate that never
would get allocated. The kernel will still use the dup, so we
have to account for that in our id counter.

Also, if we don't create a new entry, reset the id back to where
it was when zebra_nhg_find() was called.

Signed-off-by: Stephen Worley <sworley@cumulusnetworks.com>

diff --git a/zebra/zebra_nhg.c b/zebra/zebra_nhg.c
index 3c78ce525310fe78bb3f053f790a03169923b970..c6117453a2b70a86df319d90d51308aa2d0b18d1 100644 (file)
--- a/zebra/zebra_nhg.c
+++ b/zebra/zebra_nhg.c
@@ -158,29 +158,13 @@ int zebra_nhg_insert_id(struct nhg_hash_entry *nhe)
 
 static void *zebra_nhg_alloc(void *arg)
 {
-       /* lock for getiing and setting the id */
-       static pthread_mutex_t lock = PTHREAD_MUTEX_INITIALIZER;
-       /* id counter to keep in sync with kernel */
-       static uint32_t id_counter = 0;
        struct nhg_hash_entry *nhe;
        struct nhg_hash_entry *copy = arg;
 
        nhe = XCALLOC(MTYPE_NHG, sizeof(struct nhg_hash_entry));
 
-       pthread_mutex_lock(&lock); /* Lock, set the id counter from kernel */
-       if (copy->id) {
-               /* This is from the kernel if it has an id */
-               if (copy->id > id_counter) {
-                       /* Increase our counter so we don't try to create
-                        * an ID that already exists
-                        */
-                       id_counter = copy->id;
-               }
-               nhe->id = copy->id;
-       } else {
-               nhe->id = ++id_counter;
-       }
-       pthread_mutex_unlock(&lock);
+
+       nhe->id = copy->id;
 
        nhe->nhg_depends = NULL;
 
@@ -339,10 +323,31 @@ struct nhg_hash_entry *zebra_nhg_find(struct nexthop_group *nhg,
                                      vrf_id_t vrf_id, afi_t afi, uint32_t id,
                                      struct list *nhg_depends, int dep_count)
 {
+       /* lock for getiing and setting the id */
+       static pthread_mutex_t lock = PTHREAD_MUTEX_INITIALIZER;
+       /* id counter to keep in sync with kernel */
+       static uint32_t id_counter = 0;
+
        struct nhg_hash_entry lookup = {0};
        struct nhg_hash_entry *nhe = NULL;
+       uint32_t old_id_counter = 0;
+
+       pthread_mutex_lock(&lock); /* Lock, set the id counter */
+
+       old_id_counter = id_counter;
+
+       if (id) {
+               if (id > id_counter) {
+                       /* Increase our counter so we don't try to create
+                        * an ID that already exists
+                        */
+                       id_counter = id;
+               }
+               lookup.id = id;
+       } else {
+               lookup.id = ++id_counter;
+       }
 
-       lookup.id = id;
        lookup.vrf_id = vrf_id;
        lookup.afi = afi;
        lookup.nhg = nhg;
@@ -353,6 +358,12 @@ struct nhg_hash_entry *zebra_nhg_find(struct nexthop_group *nhg,
        else
                nhe = hash_lookup(zrouter.nhgs, &lookup);
 
+       /* If it found an nhe in our tables, this new ID is unused */
+       if (nhe)
+               id_counter = old_id_counter;
+
+       pthread_mutex_unlock(&lock);
+
        if (!nhe)
                nhe = hash_get(zrouter.nhgs, &lookup, zebra_nhg_alloc);