res_pjsip: Add support for returning only reachable contacts and use it.

This introduces the ability for PJSIP code to specify filtering flags
when retrieving PJSIP contacts. The first flag for use causes the
query code to only retrieve contacts that are not unreachable. This
change has been leveraged by both the Dial() process and the
PJSIP_DIAL_CONTACTS dialplan function so they will now only attempt
calls to contacts which are not unreachable.

ASTERISK-26281

Change-Id: I8233b4faa21ba3db114f5a42e946e4b191446f6c

6 files changed, 128 insertions, 6 deletions

diff --git a/CHANGES b/CHANGES
index 94405bf4a..4b690247d 100644
--- a/CHANGES
+++ b/CHANGES
@@ -19,6 +19,12 @@ res_agi
    EAGI provides. If not specified, it will continue to use the default signed
    linear (slin).
 
+chan_pjsip
+------------------
+ * When dialing an endpoint directly or using the PJSIP_DIAL_CONTACTS dialplan
+   function any contact which is considered unreachable due to qualify being
+   enabled will no longer be called.
+
 ------------------------------------------------------------------------------
 --- Functionality changes from Asterisk 13.15.0 to Asterisk 13.16.0 ----------
 ------------------------------------------------------------------------------
diff --git a/channels/pjsip/dialplan_functions.c b/channels/pjsip/dialplan_functions.c
index 652a6b7f3..d11636ccc 100644
--- a/channels/pjsip/dialplan_functions.c
+++ b/channels/pjsip/dialplan_functions.c
@@ -898,7 +898,7 @@ int pjsip_acf_dial_contacts_read(struct ast_channel *chan, const char *cmd, char
 		if (!aor) {
 			/* If the AOR provided is not found skip it, there may be more */
 			continue;
-		} else if (!(contacts = ast_sip_location_retrieve_aor_contacts(aor))) {
+		} else if (!(contacts = ast_sip_location_retrieve_aor_contacts_filtered(aor, AST_SIP_CONTACT_FILTER_REACHABLE))) {
 			/* No contacts are available, skip it as well */
 			continue;
 		} else if (!ao2_container_count(contacts)) {
diff --git a/include/asterisk/res_pjsip.h b/include/asterisk/res_pjsip.h
index 59122b987..66a744d68 100644
--- a/include/asterisk/res_pjsip.h
+++ b/include/asterisk/res_pjsip.h
@@ -869,6 +869,17 @@ struct ast_sip_endpoint_identifier {
 };
 
 /*!
+ * \brief Contact retrieval filtering flags
+ */
+enum ast_sip_contact_filter {
+	/*! \brief Default filter flags */
+	AST_SIP_CONTACT_FILTER_DEFAULT = 0,
+
+	/*! \brief Return only reachable or unknown contacts */
+	AST_SIP_CONTACT_FILTER_REACHABLE = (1 << 0),
+};
+
+/*!
  * \brief Register a SIP service in Asterisk.
  *
  * This is more-or-less a wrapper around pjsip_endpt_register_module().
@@ -1054,6 +1065,18 @@ struct ast_sip_aor *ast_sip_location_retrieve_aor(const char *aor_name);
 struct ast_sip_contact *ast_sip_location_retrieve_first_aor_contact(const struct ast_sip_aor *aor);
 
 /*!
+ * \brief Retrieve the first bound contact for an AOR and filter based on flags
+ * \since 13.16.0
+ *
+ * \param aor Pointer to the AOR
+ * \param flags Filtering flags
+ * \retval NULL if no contacts available
+ * \retval non-NULL if contacts available
+ */
+struct ast_sip_contact *ast_sip_location_retrieve_first_aor_contact_filtered(const struct ast_sip_aor *aor,
+	unsigned int flags);
+
+/*!
  * \brief Retrieve all contacts currently available for an AOR
  *
  * \param aor Pointer to the AOR
@@ -1068,6 +1091,23 @@ struct ast_sip_contact *ast_sip_location_retrieve_first_aor_contact(const struct
 struct ao2_container *ast_sip_location_retrieve_aor_contacts(const struct ast_sip_aor *aor);
 
 /*!
+ * \brief Retrieve all contacts currently available for an AOR and filter based on flags
+ * \since 13.16.0
+ *
+ * \param aor Pointer to the AOR
+ * \param flags Filtering flags
+ *
+ * \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_filtered(const struct ast_sip_aor *aor,
+	unsigned int flags);
+
+/*!
  * \brief Retrieve all contacts currently available for an AOR without locking the AOR
  * \since 13.9.0
  *
@@ -1082,6 +1122,22 @@ struct ao2_container *ast_sip_location_retrieve_aor_contacts(const struct ast_si
 struct ao2_container *ast_sip_location_retrieve_aor_contacts_nolock(const struct ast_sip_aor *aor);
 
 /*!
+ * \brief Retrieve all contacts currently available for an AOR without locking the AOR and filter based on flags
+ * \since 13.16.0
+ *
+ * \param aor Pointer to the AOR
+ * \param flags Filtering flags
+ *
+ * \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_filtered(const struct ast_sip_aor *aor,
+	unsigned int flags);
+
+/*!
  * \brief Retrieve the first bound contact from a list of AORs
  *
  * \param aor_list A comma-separated list of AOR names
@@ -1110,6 +1166,18 @@ struct ao2_container *ast_sip_location_retrieve_contacts_from_aor_list(const cha
 	struct ast_sip_contact **contact);
 
 /*!
+ * \brief Retrieve the first bound contact AND the AOR chosen from a list of AORs and filter based on flags
+ * \since 13.16.0
+ *
+ * \param aor_list A comma-separated list of AOR names
+ * \param flags Filtering flags
+ * \param aor The chosen AOR
+ * \param contact The chosen contact
+ */
+void ast_sip_location_retrieve_contact_and_aor_from_list_filtered(const char *aor_list, unsigned int flags,
+	struct ast_sip_aor **aor, struct ast_sip_contact **contact);
+
+/*!
  * \brief Retrieve a named contact
  *
  * \param contact_name Name of the contact
diff --git a/res/res_pjsip.c b/res/res_pjsip.c
index d47815fec..24627addf 100644
--- a/res/res_pjsip.c
+++ b/res/res_pjsip.c
@@ -3030,7 +3030,7 @@ pjsip_dialog *ast_sip_create_dialog_uac(const struct ast_sip_endpoint *endpoint,
 	if (res != PJ_SUCCESS) {
 		if (res == PJSIP_EINVALIDURI) {
 			ast_log(LOG_ERROR,
-				"Endpoint '%s': Could not create dialog to invalid URI '%s'.  Is endpoint registered?\n",
+				"Endpoint '%s': Could not create dialog to invalid URI '%s'.  Is endpoint registered and reachable?\n",
 				ast_sorcery_object_get_id(endpoint), uri);
 		}
 		return NULL;
diff --git a/res/res_pjsip/location.c b/res/res_pjsip/location.c
index d8f0c58b5..05e19f53a 100644
--- a/res/res_pjsip/location.c
+++ b/res/res_pjsip/location.c
@@ -171,12 +171,36 @@ static int contact_link_static(void *obj, void *arg, int flags)
 	return 0;
 }
 
+/*! \brief Internal callback function which removes any contact which is unreachable */
+static int contact_remove_unreachable(void *obj, void *arg, int flags)
+{
+	struct ast_sip_contact *contact = obj;
+	struct ast_sip_contact_status *status;
+	int unreachable;
+
+	status = ast_res_pjsip_find_or_create_contact_status(contact);
+	if (!status) {
+		return 0;
+	}
+
+	unreachable = (status->status == UNAVAILABLE);
+	ao2_ref(status, -1);
+
+	return unreachable ? CMP_MATCH : 0;
+}
+
 struct ast_sip_contact *ast_sip_location_retrieve_first_aor_contact(const struct ast_sip_aor *aor)
 {
+	return ast_sip_location_retrieve_first_aor_contact_filtered(aor, AST_SIP_CONTACT_FILTER_DEFAULT);
+}
+
+struct ast_sip_contact *ast_sip_location_retrieve_first_aor_contact_filtered(const struct ast_sip_aor *aor,
+	unsigned int flags)
+{
 	struct ao2_container *contacts;
 	struct ast_sip_contact *contact = NULL;
 
-	contacts = ast_sip_location_retrieve_aor_contacts(aor);
+	contacts = ast_sip_location_retrieve_aor_contacts_filtered(aor, flags);
 	if (contacts && ao2_container_count(contacts)) {
 		/* Get the first AOR contact in the container. */
 		contact = ao2_callback(contacts, 0, NULL, NULL);
@@ -187,6 +211,12 @@ struct ast_sip_contact *ast_sip_location_retrieve_first_aor_contact(const struct
 
 struct ao2_container *ast_sip_location_retrieve_aor_contacts_nolock(const struct ast_sip_aor *aor)
 {
+	return ast_sip_location_retrieve_aor_contacts_nolock_filtered(aor, AST_SIP_CONTACT_FILTER_DEFAULT);
+}
+
+struct ao2_container *ast_sip_location_retrieve_aor_contacts_nolock_filtered(const struct ast_sip_aor *aor,
+	unsigned int flags)
+{
 	/* Give enough space for ^ at the beginning and ;@ at the end, since that is our object naming scheme */
 	char regex[strlen(ast_sorcery_object_get_id(aor)) + 4];
 	struct ao2_container *contacts;
@@ -205,11 +235,21 @@ struct ao2_container *ast_sip_location_retrieve_aor_contacts_nolock(const struct
 		ao2_callback(aor->permanent_contacts, OBJ_NODATA, contact_link_static, contacts);
 	}
 
+	if (flags & AST_SIP_CONTACT_FILTER_REACHABLE) {
+		ao2_callback(contacts, OBJ_NODATA | OBJ_MULTIPLE | OBJ_UNLINK, contact_remove_unreachable, NULL);
+	}
+
 	return contacts;
 }
 
 struct ao2_container *ast_sip_location_retrieve_aor_contacts(const struct ast_sip_aor *aor)
 {
+	return ast_sip_location_retrieve_aor_contacts_filtered(aor, AST_SIP_CONTACT_FILTER_DEFAULT);
+}
+
+struct ao2_container *ast_sip_location_retrieve_aor_contacts_filtered(const struct ast_sip_aor *aor,
+	unsigned int flags)
+{
 	struct ao2_container *contacts;
 	struct ast_named_lock *lock;
 
@@ -219,16 +259,23 @@ struct ao2_container *ast_sip_location_retrieve_aor_contacts(const struct ast_si
 	}
 
 	ao2_lock(lock);
-	contacts = ast_sip_location_retrieve_aor_contacts_nolock(aor);
+	contacts = ast_sip_location_retrieve_aor_contacts_nolock_filtered(aor, flags);
 	ao2_unlock(lock);
 	ast_named_lock_put(lock);
 
 	return contacts;
 }
 
+
 void ast_sip_location_retrieve_contact_and_aor_from_list(const char *aor_list, struct ast_sip_aor **aor,
 	struct ast_sip_contact **contact)
 {
+	ast_sip_location_retrieve_contact_and_aor_from_list_filtered(aor_list, AST_SIP_CONTACT_FILTER_DEFAULT, aor, contact);
+}
+
+void ast_sip_location_retrieve_contact_and_aor_from_list_filtered(const char *aor_list, unsigned int flags,
+	struct ast_sip_aor **aor, struct ast_sip_contact **contact)
+{
 	char *aor_name;
 	char *rest;
 
@@ -247,7 +294,7 @@ void ast_sip_location_retrieve_contact_and_aor_from_list(const char *aor_list, s
 		if (!(*aor)) {
 			continue;
 		}
-		*contact = ast_sip_location_retrieve_first_aor_contact(*aor);
+		*contact = ast_sip_location_retrieve_first_aor_contact_filtered(*aor, flags);
 		/* If a valid contact is available use its URI for dialing */
 		if (*contact) {
 			break;
diff --git a/res/res_pjsip_session.c b/res/res_pjsip_session.c
index 400eb6a84..1fec089f8 100644
--- a/res/res_pjsip_session.c
+++ b/res/res_pjsip_session.c
@@ -1717,7 +1717,8 @@ struct ast_sip_session *ast_sip_session_create_outgoing(struct ast_sip_endpoint
 	if (location || !contact) {
 		location = S_OR(location, endpoint->aors);
 
-		ast_sip_location_retrieve_contact_and_aor_from_list(location, &found_aor, &found_contact);
+		ast_sip_location_retrieve_contact_and_aor_from_list_filtered(location, AST_SIP_CONTACT_FILTER_REACHABLE,
+			&found_aor, &found_contact);
 		if (!found_contact || ast_strlen_zero(found_contact->uri)) {
 			uri = location;
 		} else {