res_pjsip contact: Lock expiration/addition of contacts

Contact expiration can occur in several places:  res_pjsip_registrar,
res_pjsip_registrar_expire, and automatically when anyone calls
ast_sip_location_retrieve_aor_contact.  At the same time, res_pjsip_registrar
may also be attempting to renew or add a contact.  Since none of this was locked
it was possible for one thread to be renewing a contact and another thread to
expire it immediately because it was working off of stale data.  This was the
casue of intermittent registration/inbound/nominal/multiple_contacts test
failures.

Now, the new named lock functionality is used to lock the aor during contact
expire and add operations and res_pjsip_registrar_expire now checks the
expiration with the lock held before deleting the contact.

ASTERISK-25885 #close
Reported-by: Josh Colp

Change-Id: I83d413c46a47796f3ab052ca3b349f21cca47059

1 files changed, 17 insertions, 1 deletions

diff --git a/res/res_pjsip_registrar_expire.c b/res/res_pjsip_registrar_expire.c
index e52363e13..0d979a13f 100644
--- a/res/res_pjsip_registrar_expire.c
+++ b/res/res_pjsip_registrar_expire.c
@@ -30,6 +30,7 @@
 
 #include "asterisk/res_pjsip.h"
 #include "asterisk/module.h"
+#include "asterisk/named_locks.h"
 
 /*! \brief Thread keeping things alive */
 static pthread_t check_thread = AST_PTHREADT_NULL;
@@ -41,8 +42,23 @@ static unsigned int check_interval;
 static int expire_contact(void *obj, void *arg, int flags)
 {
 	struct ast_sip_contact *contact = obj;
+	struct ast_named_lock *lock;
 
-	ast_sorcery_delete(ast_sip_get_sorcery(), contact);
+	lock = ast_named_lock_get(AST_NAMED_LOCK_TYPE_RWLOCK, "aor", contact->aor);
+	if (!lock) {
+		return 0;
+	}
+
+	/*
+	 * We need to check the expiration again with the aor lock held
+	 * in case another thread is attempting to renew the contact.
+	 */
+	ao2_wrlock(lock);
+	if (ast_tvdiff_ms(ast_tvnow(), contact->expiration_time) > 0) {
+		ast_sip_location_delete_contact(contact);
+	}
+	ao2_unlock(lock);
+	ast_named_lock_put(lock);
 
 	return 0;
 }