aaa_diameter: Reply to requests when E_DM_REQUEST not used

At the end of the day, we are a Diameter peer, so we should also reply
to requests even if the opensips.cfg script does not require any
server-side support (e.g. perhaps it's only pushing Diameter requests).

modules/aaa_diameter/aaa_diameter.c

@@ -49,6 +49,7 @@ str dm_realm = str_init("diameter.test");
 str dm_peer_identity = str_init("server"); /* a.k.a. server.diameter.test */
 static str dm_aaa_url = {NULL, 0};
 int dm_answer_timeout = 2000; /* ms */
+int dm_server_autoreply_error; /* ensures we always reply with *something* */
 
 static const cmd_export_t cmds[]= {
 	{"dm_send_request", (cmd_function)dm_send_request, {
@@ -200,6 +201,19 @@ static int dm_check_config(void)
 		return -1;
 	}
 
+	LM_INFO("Diameter server support enabled\n");
+
+	if (get_script_route_ID_by_name_str(
+	        &str_init(DMEV_REQ_NAME), sroutes->event, EVENT_RT_NO) < 0) {
+		LM_NOTICE("Diameter server event "DMEV_REQ_NAME" not used in opensips script"
+		        ", auto-replying error code 3001 to any Diameter request\n");
+		dm_server_autoreply_error = 1;
+	} else if (!is_script_func_used("dm_send_answer", -1)) {
+		LM_NOTICE("Diameter 'dm_send_answer()' function not used in opensips script"
+		        ", auto-replying error code 3001 to any Diameter request\n");
+		dm_server_autoreply_error = 1;
+	}
+
 	return 0;
 }
 

modules/aaa_diameter/dm_evi.c

@@ -63,7 +63,7 @@ int dm_init_evi(void)
 	}
 
 	/* First publish the events */
-	dmev_req_id = evi_publish_event(str_init("E_DM_REQUEST"));
+	dmev_req_id = evi_publish_event(str_init(DMEV_REQ_NAME));
 	if (dmev_req_id == EVI_ERROR) {
 		LM_ERR("cannot register 'request' event\n");
 		return -1;
@@ -169,7 +169,7 @@ void dm_raise_event_request(int sender, void *dm_req)
 	}
 
 	if (evi_raise_event(dmev_req_id, dmev_req_params) < 0)
-		LM_ERR("failed to raise 'E_DM_REQUEST' event\n");
+		LM_ERR("failed to raise '"DMEV_REQ_NAME"' event\n");
 
 out:
 	shm_free(job->sessid.s);

modules/aaa_diameter/dm_evi.h

@@ -33,6 +33,7 @@ typedef struct _dm_ipc_event_req {
 	str avps_json;
 } dm_ipc_event_req;
 
+#define DMEV_REQ_NAME "E_DM_REQUEST"
 extern str dmev_req_pname_sessid;
 extern str dmev_req_pname_appid;
 extern str dmev_req_pname_cmdcode;

modules/aaa_diameter/dm_impl.c

@@ -548,12 +548,27 @@ static int dm_receive_req(struct msg **_req, struct avp * avp, struct session *
 	init_str(&avp_arr, cJSON_PrintUnformatted(avps));
 
 	/* keep the request for a while in order to be able to generate the answer */
-	dm_update_unreplied_req(req);
+	if (!dm_server_autoreply_error)
+		dm_update_unreplied_req(req);
 
 	if (dm_dispatch_event_req(req, &tid, hdr->msg_appl, hdr->msg_code, &avp_arr))
 		LM_ERR("failed to dispatch DM Request (tid: %.*s, %d/%d)\n", tid.len,
 		        tid.s, hdr->msg_appl, hdr->msg_code);
 
+	if (dm_server_autoreply_error) {
+		struct dm_message dm;
+
+		memset(&dm, 0, sizeof dm);
+
+		dm.fd_req = req;
+		dm.app_id = hdr->msg_appl;
+		dm.cmd_code = hdr->msg_code;
+
+		if (dm_send_custom_rpl(&dm, 1) != 0)
+			LM_ERR("failed to auto-reply with error, tid: %.*s, %d/%d\n", tid.len,
+			        tid.s, hdr->msg_appl, hdr->msg_code);
+	}
+
 	goto out;
 
 error:

modules/aaa_diameter/dm_impl.h

@@ -144,6 +144,7 @@ extern char *dm_conf_filename;
 extern char *extra_avps_file;
 extern struct _dm_dict dm_dict;
 extern int dm_answer_timeout;
+extern int dm_server_autoreply_error;
 int dm_remove_unreplied_req(struct msg *req);
 
 int freeDiameter_init(void);

modules/aaa_diameter/dm_peer.c

@@ -102,7 +102,7 @@ static inline int dm_add_session(struct msg *msg, struct dict_object *model)
 }
 
 
-static int dm_auth(struct dm_message *msg)
+static int dm_send_auth(struct dm_message *msg)
 {
 	struct msg *dmsg;
 	struct dm_avp *dm_avp;
@@ -246,7 +246,7 @@ static int dm_auth(struct dm_message *msg)
 }
 
 
-static int dm_acct(struct dm_message *msg)
+static int dm_send_acct(struct dm_message *msg)
 {
 	struct msg *dmsg;
 	struct avp *avp;
@@ -450,7 +450,7 @@ static int dm_pack_avps(void *root, struct list_head *subavps)
 }
 
 
-static int dm_custom_req(struct dm_message *msg)
+static int dm_send_custom_req(struct dm_message *msg)
 {
 	str tid_str;
 	struct msg *dmsg;
@@ -509,23 +509,30 @@ static int dm_custom_req(struct dm_message *msg)
 }
 
 
-static int dm_custom_rpl(struct dm_message *dm)
+int dm_send_custom_rpl(struct dm_message *dm, int is_error)
 {
 	struct msg *ans = (struct msg *)dm->fd_req;
-	int rc;
+	int rc, flags = 0;
 
-	if (dm_remove_unreplied_req(ans) != 0) {
+	if (!dm_server_autoreply_error && dm_remove_unreplied_req(ans) != 0) {
 		LM_ERR("unable to build answer, request is no longer available "
 		        "(timeout: %d s)\n", dm_unreplied_req_timeout);
 		return -1;
 	}
 
-	rc = fd_msg_new_answer_from_req(fd_g_config->cnf_dict, &ans, 0);
+	if (is_error)
+		flags |= MSGFL_ANSW_ERROR;
+
+	rc = fd_msg_new_answer_from_req(fd_g_config->cnf_dict, &ans, flags);
 	if (rc != 0) {
 		LM_ERR("failed to create answer message, error: %d\n", rc);
 		goto error;
 	}
 
+	if (is_error)
+		FD_CHECK(fd_msg_rescode_set(ans, "DIAMETER_COMMAND_UNSUPPORTED",
+		            "Command Not Implemented", NULL, 1));
+
 	/* App id */
 	{
 		struct msg_hdr *h;
@@ -534,7 +541,7 @@ static int dm_custom_rpl(struct dm_message *dm)
 	}
 
 	/* include all AVPs passed from script level */
-	if (dm_pack_avps(ans, &dm->avps) != 0) {
+	if (!dm_server_autoreply_error && dm_pack_avps(ans, &dm->avps) != 0) {
 		LM_ERR("failed to pack AVPs\n");
 		return -1;
 	}
@@ -555,13 +562,13 @@ static inline int dm_peer_send_msg(struct dm_message *msg)
 
 	switch (am->type) {
 	case AAA_AUTH:
-		return dm_auth(msg);
+		return dm_send_auth(msg);
 	case AAA_ACCT:
-		return dm_acct(msg);
+		return dm_send_acct(msg);
 	case AAA_CUSTOM_REQ:
-		return dm_custom_req(msg);
+		return dm_send_custom_req(msg);
 	case AAA_CUSTOM_RPL:
-		return dm_custom_rpl(msg);
+		return dm_send_custom_rpl(msg, 0);
 	default:
 		LM_ERR("unsupported AAA message type (%d), skipping\n", am->type);
 	}

modules/aaa_diameter/dm_peer.h

@@ -27,5 +27,6 @@ extern pthread_mutex_t *msg_send_lk;
 
 int dm_init_peer(void);
 void dm_peer_loop(int _);
+int dm_send_custom_rpl(struct dm_message *dm, int is_error);
 
 #endif