ovn: Fix tunnel id overflow.

Reported-by: Wei Li <liwei@anbutu.com>
Signed-off-by: Ben Pfaff <blp@ovn.org>

1 files changed, 8 insertions, 2 deletions

diff --git a/ovn/northd/ovn-northd.c b/ovn/northd/ovn-northd.c
index 6000856f3..afa152d42 100644
--- a/ovn/northd/ovn-northd.c
+++ b/ovn/northd/ovn-northd.c
@@ -210,11 +210,17 @@ tnlid_in_use(const struct hmap *set, uint32_t tnlid)
 }
 
 static uint32_t
+next_tnlid(uint32_t tnlid, uint32_t max)
+{
+    return tnlid + 1 <= max ? tnlid + 1 : 1;
+}
+
+static uint32_t
 allocate_tnlid(struct hmap *set, const char *name, uint32_t max,
                uint32_t *hint)
 {
-    for (uint32_t tnlid = *hint + 1; tnlid != *hint;
-         tnlid = tnlid + 1 <= max ? tnlid + 1 : 1) {
+    for (uint32_t tnlid = next_tnlid(*hint, max); tnlid != *hint;
+         tnlid = next_tnlid(tnlid, max)) {
         if (!tnlid_in_use(set, tnlid)) {
             add_tnlid(set, tnlid);
             *hint = tnlid;