Ensure that the number of added contacts never goes below 0.

This can happen when a REGISTER request is removing a contact.

(closes issue ASTERISK-21911)
Reported by: mdavenport

git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@391902 65c4cc65-6c06-0410-ace0-fbb531ad65f3

diff --git a/res/res_sip_registrar.c b/res/res_sip_registrar.c
index 0cc5821ee0a9c98961f408563836ca80a284b1ae..c3315d0becda2c2979290c49e1f7bf5db36a5896 100644 (file)
--- a/res/res_sip_registrar.c
+++ b/res/res_sip_registrar.c
@@ -259,7 +259,7 @@ static pj_bool_t registrar_on_rx_request(struct pjsip_rx_data *rdata)
                return PJ_TRUE;
        }
 
-       if (((added - deleted) + (!aor->remove_existing ? ao2_container_count(contacts) : 0)) > aor->max_contacts) {
+       if ((MAX(added - deleted, 0) + (!aor->remove_existing ? ao2_container_count(contacts) : 0)) > aor->max_contacts) {
                /* Enforce the maximum number of contacts */
                pjsip_endpt_respond_stateless(ast_sip_get_pjsip_endpoint(), rdata, 403, NULL, NULL, NULL);
                return PJ_TRUE;