res_pjsip: Patch for res_pjsip_* module load/reload crash

The session_supplements for the pjsip makes crashes when the module
load/unload.

ASTERISK-28157

Change-Id: I5b82be3a75d702cf1933d8d1417f44aa10ad1029

include/asterisk/res_pjsip_session.h

@@ -258,6 +258,8 @@ enum ast_sip_session_response_priority {
  * processing to incoming and outgoing SIP requests and responses
  */
 struct ast_sip_session_supplement {
+	/*! Reference module info */
+	struct ast_module *module;
 	/*! Method on which to call the callbacks. If NULL, call on all methods */
 	const char *method;
 	/*! Priority for this supplement. Lower numbers are visited before higher numbers */
@@ -580,9 +582,13 @@ void ast_sip_session_unregister_sdp_handler(struct ast_sip_session_sdp_handler *
  * set channel data based on headers in an incoming message. Similarly,
  * a module could reject an incoming request if desired.
  *
+ * \param module Referenced module(NULL safe)
  * \param supplement The supplement to register
  */
-void ast_sip_session_register_supplement(struct ast_sip_session_supplement *supplement);
+void ast_sip_session_register_supplement_with_module(struct ast_module *module, struct ast_sip_session_supplement *supplement);
+
+#define ast_sip_session_register_supplement(supplement) \
+		ast_sip_session_register_supplement_with_module(AST_MODULE_SELF, supplement)
 
 /*!
  * \brief Unregister a an supplement to SIP session processing
@@ -598,6 +604,13 @@ void ast_sip_session_unregister_supplement(struct ast_sip_session_supplement *su
  */
 int ast_sip_session_add_supplements(struct ast_sip_session *session);
 
+/*!
+ * \brief Remove supplements from a SIP session
+ *
+ * \param session The session to remove
+ */
+void ast_sip_session_remove_supplements(struct ast_sip_session *session);
+
 /*!
  * \brief Alternative for ast_datastore_alloc()
  *

res/res_pjsip/pjsip_message_filter.c

@@ -24,6 +24,7 @@
 #include "asterisk/res_pjsip.h"
 #include "asterisk/res_pjsip_session.h"
 #include "include/res_pjsip_private.h"
+#include "asterisk/module.h"
 
 #define MOD_DATA_RESTRICTIONS "restrictions"
 

res/res_pjsip/pjsip_session.c

@@ -32,12 +32,16 @@
 
 AST_RWLIST_HEAD_STATIC(session_supplements, ast_sip_session_supplement);
 
-void ast_sip_session_register_supplement(struct ast_sip_session_supplement *supplement)
+void ast_sip_session_register_supplement_with_module(struct ast_module *module, struct ast_sip_session_supplement *supplement)
 {
 	struct ast_sip_session_supplement *iter;
 	int inserted = 0;
 	SCOPED_LOCK(lock, &session_supplements, AST_RWLIST_WRLOCK, AST_RWLIST_UNLOCK);
 
+	ast_assert(supplement != NULL);
+
+	supplement->module = module;
+
 	if (!supplement->response_priority) {
 		supplement->response_priority = AST_SIP_SESSION_BEFORE_MEDIA;
 	}
@@ -94,8 +98,34 @@ int ast_sip_session_add_supplements(struct ast_sip_session *session)
 		if (!copy) {
 			return -1;
 		}
+
+		/* referenced session created. increasing module reference. */
+		ast_module_ref(copy->module);
+
 		AST_LIST_INSERT_TAIL(&session->supplements, copy, next);
 	}
 
 	return 0;
 }
+
+void ast_sip_session_remove_supplements(struct ast_sip_session *session)
+{
+	struct ast_sip_session_supplement *iter;
+
+	if (!session) {
+		return;
+	}
+
+	/* free the supplements */
+	while ((iter = AST_LIST_REMOVE_HEAD(&session->supplements, next))) {
+		if (iter->module) {
+			/* referenced session closed. decreasing modue reference. */
+			ast_module_unref(iter->module);
+		}
+
+		ast_free(iter);
+	}
+
+	return;
+}
+

res/res_pjsip_session.c

@@ -58,6 +58,9 @@
 #define DEFAULT_NUM_SESSION_MEDIA 2
 
 /* Some forward declarations */
+static void handle_session_begin(struct ast_sip_session *session);
+static void handle_session_end(struct ast_sip_session *session);
+static void handle_session_destroy(struct ast_sip_session *session);
 static void handle_incoming_request(struct ast_sip_session *session, pjsip_rx_data *rdata);
 static void handle_incoming_response(struct ast_sip_session *session, pjsip_rx_data *rdata,
 		enum ast_sip_session_response_priority response_priority);
@@ -2088,7 +2091,6 @@ static int datastore_cmp(void *obj, void *arg, int flags)
 static void session_destructor(void *obj)
 {
 	struct ast_sip_session *session = obj;
-	struct ast_sip_session_supplement *supplement;
 	struct ast_sip_session_delayed_request *delay;
 	const char *endpoint_name = session->endpoint ?
 		ast_sorcery_object_get_id(session->endpoint) : "<none>";
@@ -2104,19 +2106,18 @@ static void session_destructor(void *obj)
 		, session->contact ? ast_sorcery_object_get_id(session->contact) : "<none>"
 		);
 
-	while ((supplement = AST_LIST_REMOVE_HEAD(&session->supplements, next))) {
-		if (supplement->session_destroy) {
-			supplement->session_destroy(session);
-		}
-		ast_free(supplement);
-	}
+	/* fire session destroy handler */
+	handle_session_destroy(session);
+
+	/* remove all registered supplements */
+	ast_sip_session_remove_supplements(session);
+	AST_LIST_HEAD_DESTROY(&session->supplements);
 
 	ast_taskprocessor_unreference(session->serializer);
 	ao2_cleanup(session->datastores);
 	ast_sip_session_media_state_free(session->active_media_state);
 	ast_sip_session_media_state_free(session->pending_media_state);
 
-	AST_LIST_HEAD_DESTROY(&session->supplements);
 	while ((delay = AST_LIST_REMOVE_HEAD(&session->delayed_requests, next))) {
 		delayed_request_free(delay);
 	}
@@ -2165,7 +2166,6 @@ struct ast_sip_session *ast_sip_session_alloc(struct ast_sip_endpoint *endpoint,
 {
 	RAII_VAR(struct ast_sip_session *, session, NULL, ao2_cleanup);
 	struct ast_sip_session *ret_session;
-	struct ast_sip_session_supplement *iter;
 	int dsp_features = 0;
 
 	session = ao2_alloc(sizeof(*session), session_destructor);
@@ -2247,11 +2247,9 @@ struct ast_sip_session *ast_sip_session_alloc(struct ast_sip_endpoint *endpoint,
 		ao2_ref(session, -1);
 		return NULL;
 	}
-	AST_LIST_TRAVERSE(&session->supplements, iter, next) {
-		if (iter->session_begin) {
-			iter->session_begin(session);
-		}
-	}
+
+	/* Fire seesion begin handlers */
+	handle_session_begin(session);
 
 	/* Avoid unnecessary ref manipulation to return a session */
 	ret_session = session;
@@ -3316,6 +3314,40 @@ static void handle_incoming_request(struct ast_sip_session *session, pjsip_rx_da
 	}
 }
 
+static void handle_session_begin(struct ast_sip_session *session)
+{
+	struct ast_sip_session_supplement *iter;
+
+	AST_LIST_TRAVERSE(&session->supplements, iter, next) {
+		if (iter->session_begin) {
+			iter->session_begin(session);
+		}
+	}
+}
+
+static void handle_session_destroy(struct ast_sip_session *session)
+{
+	struct ast_sip_session_supplement *iter;
+
+	AST_LIST_TRAVERSE(&session->supplements, iter, next) {
+		if (iter->session_destroy) {
+			iter->session_destroy(session);
+		}
+	}
+}
+
+static void handle_session_end(struct ast_sip_session *session)
+{
+	struct ast_sip_session_supplement *iter;
+
+	/* Session is dead.  Notify the supplements. */
+	AST_LIST_TRAVERSE(&session->supplements, iter, next) {
+		if (iter->session_end) {
+			iter->session_end(session);
+		}
+	}
+}
+
 static void handle_incoming_response(struct ast_sip_session *session, pjsip_rx_data *rdata,
 		enum ast_sip_session_response_priority response_priority)
 {
@@ -3393,17 +3425,13 @@ static void handle_outgoing_response(struct ast_sip_session *session, pjsip_tx_d
 static int session_end(void *vsession)
 {
 	struct ast_sip_session *session = vsession;
-	struct ast_sip_session_supplement *iter;
 
 	/* Stop the scheduled termination */
 	sip_session_defer_termination_stop_timer(session);
 
 	/* Session is dead.  Notify the supplements. */
-	AST_LIST_TRAVERSE(&session->supplements, iter, next) {
-		if (iter->session_end) {
-			iter->session_end(session);
-		}
-	}
+	handle_session_end(session);
+
 	return 0;
 }