https://issues.asterisk.org/jira/browse/ASTERISK-26518

commit 500470607eae4144b44ed4f188cfff437d56f0e7
Author: Alex Hermann <alex@hexla.nl>
Date:   Fri Jan 20 11:09:01 2017 +0100

    pjsip: Restore multihomed module
    
    Since the automatic dual stack commit, the multihome module has become
    part of the pjsip core module. This caused a circular dependency loop
    preventing the pjsip module from loading. By putting the logic back into
    its own module, things can be loaded again.

diff --git a/res/res_pjsip.c b/res/res_pjsip.c
index dd4a619d2a..6e9523d76b 100644
--- a/res/res_pjsip.c
+++ b/res/res_pjsip.c
@@ -4317,6 +4317,5 @@ static int unload_pjsip(void *data)
 	if (ast_pjsip_endpoint && serializer_pool[0]) {
 		ast_res_pjsip_cleanup_options_handling();
-		ast_res_pjsip_cleanup_message_ip_updater();
 		ast_sip_destroy_distributor();
 		ast_res_pjsip_destroy_configuration();
 		ast_sip_destroy_system();
@@ -4488,11 +4487,6 @@ static int load_module(void)
 
 	ast_res_pjsip_init_options_handling(0);
 
-	if (ast_res_pjsip_init_message_ip_updater()) {
-		ast_log(LOG_ERROR, "Failed to initialize message IP updating. Aborting load\n");
-		goto error;
-	}
-
 	ast_cli_register_multiple(cli_commands, ARRAY_LEN(cli_commands));
 
 	AST_TEST_REGISTER(xml_sanitization_end_null);
diff --git a/res/res_pjsip/pjsip_message_ip_updater.c b/res/res_pjsip_multihomed.c
similarity index 94%
rename from res/res_pjsip/pjsip_message_ip_updater.c
rename to res/res_pjsip_multihomed.c
index 7671ad0a75..3a29255973 100644
--- a/res/res_pjsip/pjsip_message_ip_updater.c
+++ b/res/res_pjsip_multihomed.c
@@ -16,6 +16,12 @@
  * at the top of the source tree.
  */
 
+/*** MODULEINFO
+	<depend>pjproject</depend>
+	<depend>res_pjsip</depend>
+	<support_level>core</support_level>
+ ***/
+
 #include "asterisk.h"
 
 #include <pjsip.h>
@@ -23,7 +29,8 @@
 
 #include "asterisk/res_pjsip.h"
 #include "asterisk/res_pjsip_session.h"
-#include "include/res_pjsip_private.h"
+#include "res_pjsip/include/res_pjsip_private.h"
+#include "asterisk/module.h"
 
 #define MOD_DATA_RESTRICTIONS "restrictions"
 
@@ -273,31 +280,41 @@ static pj_status_t multihomed_on_tx_message(pjsip_tx_data *tdata)
 	return PJ_SUCCESS;
 }
 
-void ast_res_pjsip_cleanup_message_ip_updater(void)
+static int unload_module(void)
 {
 	ast_sip_unregister_service(&multihomed_module);
 	ast_sip_unregister_supplement(&multihomed_supplement);
 	ast_sip_session_unregister_supplement(&multihomed_session_supplement);
+	return 0;
 }
 
-int ast_res_pjsip_init_message_ip_updater(void)
+static int load_module(void)
 {
+	CHECK_PJSIP_MODULE_LOADED();
+
 	if (ast_sip_session_register_supplement(&multihomed_session_supplement)) {
 		ast_log(LOG_ERROR, "Could not register multihomed session supplement for outgoing requests\n");
-		return -1;
+		return AST_MODULE_LOAD_FAILURE;
 	}
 
 	if (ast_sip_register_supplement(&multihomed_supplement)) {
 		ast_log(LOG_ERROR, "Could not register multihomed supplement for outgoing requests\n");
-		ast_res_pjsip_cleanup_message_ip_updater();
-		return -1;
+		unload_module();
+		return AST_MODULE_LOAD_FAILURE;
 	}
 
 	if (ast_sip_register_service(&multihomed_module)) {
 		ast_log(LOG_ERROR, "Could not register multihomed module for incoming and outgoing requests\n");
-		ast_res_pjsip_cleanup_message_ip_updater();
-		return -1;
+		unload_module();
+		return AST_MODULE_LOAD_FAILURE;
 	}
 
-	return 0;
+	return AST_MODULE_LOAD_SUCCESS;
 }
+
+AST_MODULE_INFO(ASTERISK_GPL_KEY, AST_MODFLAG_LOAD_ORDER, "PJSIP Multihomed Routing Support",
+	.support_level = AST_MODULE_SUPPORT_CORE,
+	.load = load_module,
+	.unload = unload_module,
+	.load_pri = AST_MODPRI_CHANNEL_DEPEND,
+);