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, 43 insertions, 0 deletions

diff --git a/include/asterisk/res_pjsip.h b/include/asterisk/res_pjsip.h
index fbb9bdcbe..3a9d61e4c 100644
--- a/include/asterisk/res_pjsip.h
+++ b/include/asterisk/res_pjsip.h
@@ -1004,10 +1004,28 @@ struct ast_sip_contact *ast_sip_location_retrieve_first_aor_contact(const struct
  *
  * \retval NULL if no contacts available
  * \retval non-NULL if contacts available
+ *
+ * \warning
+ * Since this function prunes expired contacts before returning, it holds a named write
+ * lock on the aor.  If you already hold the lock, call ast_sip_location_retrieve_aor_contacts_nolock instead.
  */
 struct ao2_container *ast_sip_location_retrieve_aor_contacts(const struct ast_sip_aor *aor);
 
 /*!
+ * \brief Retrieve all contacts currently available for an AOR without locking the AOR
+ * \since 13.9.0
+ *
+ * \param aor Pointer to the AOR
+ *
+ * \retval NULL if no contacts available
+ * \retval non-NULL if contacts available
+ *
+ * \warning
+ * This function should only be called if you already hold a named write lock on the aor.
+ */
+struct ao2_container *ast_sip_location_retrieve_aor_contacts_nolock(const struct ast_sip_aor *aor);
+
+/*!
  * \brief Retrieve the first bound contact from a list of AORs
  *
  * \param aor_list A comma-separated list of AOR names
@@ -1057,12 +1075,37 @@ struct ast_sip_contact *ast_sip_location_retrieve_contact(const char *contact_na
  *
  * \retval -1 failure
  * \retval 0 success
+ *
+ * \warning
+ * This function holds a named write lock on the aor.  If you already hold the lock
+ * you should call ast_sip_location_add_contact_nolock instead.
  */
 int ast_sip_location_add_contact(struct ast_sip_aor *aor, const char *uri,
 	struct timeval expiration_time, const char *path_info, const char *user_agent,
 	struct ast_sip_endpoint *endpoint);
 
 /*!
+ * \brief Add a new contact to an AOR without locking the AOR
+ * \since 13.9.0
+ *
+ * \param aor Pointer to the AOR
+ * \param uri Full contact URI
+ * \param expiration_time Optional expiration time of the contact
+ * \param path_info Path information
+ * \param user_agent User-Agent header from REGISTER request
+ * \param endpoint The endpoint that resulted in the contact being added
+ *
+ * \retval -1 failure
+ * \retval 0 success
+ *
+ * \warning
+ * This function should only be called if you already hold a named write lock on the aor.
+ */
+int ast_sip_location_add_contact_nolock(struct ast_sip_aor *aor, const char *uri,
+	struct timeval expiration_time, const char *path_info, const char *user_agent,
+	struct ast_sip_endpoint *endpoint);
+
+/*!
  * \brief Update a contact
  *
  * \param contact New contact object with details