res_pjsip: Added a norefersub configuration setting

Added a new PJSIP global setting called norefersub.
Default is true to keep support working as before.

res_pjsip_refer:  Configures PJSIP norefersub capability accordingly.

Checks the PJSIP global setting value.
If it is true (default) it adds the norefersub capability to PJSIP.
If it is false (disabled) it does not add the norefersub capability
to PJSIP.

This is useful for Cisco switches that do not follow RFC4488.

ASTERISK-28375 #close
Reported-by: Dan Cropp

Change-Id: I0b1c28ebc905d881f4a16e752715487a688b30e9

configs/samples/pjsip.conf.sample

@@ -1158,6 +1158,11 @@
                 ; with extreme caution and only to mitigate specific issues.
                 ; Under certain conditions they could make things worse.
 
+;norefersub=yes     ; Enable sending norefersub option tag in Supported header to advertise
+                    ; that the User Agent is capable of accepting a REFER request with
+                    ; creating an implicit subscription (see RFC 4488).
+                    ; (default: "yes")
+
 ; MODULE PROVIDING BELOW SECTION(S): res_pjsip_acl
 ;==========================ACL SECTION OPTIONS=========================
 ;[acl]

contrib/ast-db-manage/config/versions/3a094a18e75b_pjsip_add_norefersub.py

@@ -0,0 +1,39 @@
+"""pjsip add norefersub
+
+Revision ID: 3a094a18e75b
+Revises: 80473bad3c16
+Create Date: 2019-04-17 09:25:42.040269
+
+"""
+
+# revision identifiers, used by Alembic.
+revision = '3a094a18e75b'
+down_revision = '80473bad3c16'
+
+from alembic import op
+import sqlalchemy as sa
+from sqlalchemy.dialects.postgresql import ENUM
+
+AST_BOOL_NAME = 'ast_bool_values'
+# We'll just ignore the n/y and f/t abbreviations as Asterisk does not write
+# those aliases.
+AST_BOOL_VALUES = [ '0', '1',
+                    'off', 'on',
+                    'false', 'true',
+                    'no', 'yes' ]
+
+
+def upgrade():
+    ############################# Enums ##############################
+
+    # ast_bool_values has already been created, so use postgres enum object
+    # type to get around "already created" issue - works okay with mysql
+    ast_bool_values = ENUM(*AST_BOOL_VALUES, name=AST_BOOL_NAME, create_type=True)
+
+    op.add_column('ps_globals', sa.Column('norefersub', ast_bool_values))
+
+
+def downgrade():
+    if op.get_context().bind.dialect.name == 'mssql':
+        op.drop_constraint('ck_ps_globals_norefersub_ast_bool_values', 'ps_globals')
+    op.drop_column('ps_globals', 'norefersub')

doc/CHANGES-staging/res_pjsip_add_norefersub_global_config.txt

@@ -0,0 +1,13 @@
+res_pjsip:  Added a norefersub configuration setting
+
+Added a new PJSIP global setting called norefersub.
+Default is true to keep support working as before.
+
+res_pjsip_refer:  Configures PJSIP norefersub capability accordingly.
+
+Checks the PJSIP global setting value.
+If it is true (default) it adds the norefersub capability to PJSIP.
+If it is false (disabled) it does not add the norefersub capability
+to PJSIP.
+
+This is useful for Cisco switches that do not follow RFC4488.

include/asterisk/res_pjsip.h

@@ -2761,6 +2761,13 @@ unsigned int ast_sip_get_mwi_disable_initial_unsolicited(void);
  */
 unsigned int ast_sip_get_use_callerid_contact(void);
 
+/*!
+ * \brief Retrieve the global setting 'norefersub'.
+ *
+ * \retval non zero if norefersub is to be sent in "Supported" Headers
+ */
+unsigned int ast_sip_get_norefersub(void);
+
 /*!
  * \brief Retrieve the global setting 'ignore_uri_user_options'.
  * \since 13.12.0

res/res_pjsip.c

@@ -1927,6 +1927,9 @@
 						</para></warning>
 					</description>
 				</configOption>
+				<configOption name="norefersub" default="yes">
+					<synopsis>Advertise support for RFC4488 REFER subscription suppression</synopsis>
+				</configOption>
 			</configObject>
 		</configFile>
 	</configInfo>

res/res_pjsip/config_global.c

@@ -52,6 +52,7 @@
 #define DEFAULT_USE_CALLERID_CONTACT 0
 #define DEFAULT_SEND_CONTACT_STATUS_ON_UPDATE_REGISTRATION 0
 #define DEFAULT_TASKPROCESSOR_OVERLOAD_TRIGGER TASKPROCESSOR_OVERLOAD_TRIGGER_GLOBAL
+#define DEFAULT_NOREFERSUB 1
 
 /*!
  * \brief Cached global config object
@@ -113,6 +114,8 @@ struct global_config {
 	unsigned int send_contact_status_on_update_registration;
 	/*! Trigger the distributor should use to pause accepting new dialogs */
 	enum ast_sip_taskprocessor_overload_trigger overload_trigger;
+	/*! Nonzero if norefersub is to be sent in Supported header */
+	unsigned int norefersub;
 };
 
 static void global_destructor(void *obj)
@@ -501,6 +504,21 @@ enum ast_sip_taskprocessor_overload_trigger ast_sip_get_taskprocessor_overload_t
 	return trigger;
 }
 
+unsigned int ast_sip_get_norefersub(void)
+{
+	unsigned int norefersub;
+	struct global_config *cfg;
+
+	cfg = get_global_cfg();
+	if (!cfg) {
+		return DEFAULT_NOREFERSUB;
+	}
+
+	norefersub = cfg->norefersub;
+	ao2_ref(cfg, -1);
+	return norefersub;
+}
+
 static int overload_trigger_handler(const struct aco_option *opt,
 	struct ast_variable *var, void *obj)
 {
@@ -704,6 +722,9 @@ int ast_sip_initialize_sorcery_global(void)
 	ast_sorcery_object_field_register_custom(sorcery, "global", "taskprocessor_overload_trigger",
 		overload_trigger_map[DEFAULT_TASKPROCESSOR_OVERLOAD_TRIGGER],
 		overload_trigger_handler, overload_trigger_to_str, NULL, 0, 0);
+	ast_sorcery_object_field_register(sorcery, "global", "norefersub",
+		DEFAULT_NOREFERSUB ? "yes" : "no",
+		OPT_YESNO_T, 1, FLDSET(struct global_config, norefersub));
 
 	if (ast_sorcery_instance_observer_add(sorcery, &observer_callbacks_global)) {
 		return -1;

res/res_pjsip_refer.c

@@ -1230,7 +1230,10 @@ static int load_module(void)
 
 	pjsip_replaces_init_module(ast_sip_get_pjsip_endpoint());
 	pjsip_xfer_init_module(ast_sip_get_pjsip_endpoint());
-	pjsip_endpt_add_capability(ast_sip_get_pjsip_endpoint(), NULL, PJSIP_H_SUPPORTED, NULL, 1, &str_norefersub);
+
+	if (ast_sip_get_norefersub()) {
+		pjsip_endpt_add_capability(ast_sip_get_pjsip_endpoint(), NULL, PJSIP_H_SUPPORTED, NULL, 1, &str_norefersub);
+	}
 
 	ast_sip_register_service(&refer_progress_module);
 	ast_sip_session_register_supplement(&refer_supplement);