net: ocpp: Add a support for Open Charge Point Protocol(OCPP v1.6) stack

Basic support for open charge point protocol v1.6 as native stack with
below functionality

1. Framework for ocpp stack and central system communication using RPC over
   websocket according to occp-j.
2. Core profile with basic PDU

Signed-off-by: Saravanan Sekar <[email protected]>
Co-authored-by: Sanjay Vallimanalan <[email protected]>

Author: ssekar15

include/zephyr/net/ocpp.h

@@ -0,0 +1,257 @@
+/*
+ * Copyright (c) 2024 Linumiz
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+/**
+ * @file ocpp.h
+ *
+ * @defgroup ocpp_api OCPP library
+ * @since 4.3
+ * @version 0.1.0
+ * @ingroup networking
+ * @{
+ * @brief OCPP Charge Point Implementation
+ *
+ * @note The implementation assumes Websocket module is enabled.
+ *
+ * @note By default the implementation uses OCPP version 1.6.
+ */
+
+#ifndef ZEPHYR_INCLUDE_NET_OCPP_H_
+#define ZEPHYR_INCLUDE_NET_OCPP_H_
+
+#include <stdio.h>
+#include <zephyr/kernel.h>
+#include <zephyr/net/net_ip.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/** Max length of string literals e.g idtag */
+#define CISTR50	50
+
+/**
+ * @brief OCPP IdTag authorization status in result to ocpp request
+ *        authorization
+ */
+enum ocpp_auth_status {
+	OCPP_AUTH_INVALID,	/*< IdTag not valid */
+	OCPP_AUTH_ACCEPTED,	/*< accepted, allowed to charge */
+	OCPP_AUTH_BLOCKED,	/*< blocked to charge */
+	OCPP_AUTH_EXPIRED,	/*< IdTag expired, not allowed to charge */
+	OCPP_AUTH_CONCURRENT_TX /*< Parallel access of same IdTag */
+};
+
+enum ocpp_notify_reason {
+	/** User must fill the current reading */
+	OCPP_USR_GET_METER_VALUE,
+
+	/** Process the start charging request as like idtag received from local
+	 *  e.g authorize etc
+	 */
+	OCPP_USR_START_CHARGING,
+
+	/** Process the stop charging sequence */
+	OCPP_USR_STOP_CHARGING,
+
+	/** Unlock mechanical connector of CP */
+	OCPP_USR_UNLOCK_CONNECTOR,
+};
+
+/** @brief OCPP meter readings to be filled on user callback request from
+ *         library
+ */
+enum ocpp_meter_measurand {
+	OCPP_OMM_CURRENT_FROM_EV,		/*< current from EV, in A */
+	OCPP_OMM_CURRENT_TO_EV,			/*< current to EV, in A */
+	OCPP_OMM_CURRENT_MAX_OFFERED_TO_EV,	/*< maximum current offered to EV, in A */
+	OCPP_OMM_ACTIVE_ENERGY_FROM_EV,		/*< active energy from EV, in Wh */
+	OCPP_OMM_ACTIVE_ENERGY_TO_EV,		/*< active energy to EV, in Wh */
+	OCPP_OMM_REACTIVE_ENERGY_FROM_EV,	/*< reactive energy from EV, in varh */
+	OCPP_OMM_REACTIVE_ENERGY_TO_EV,		/*< reactive energy to EV, in varh */
+	OCPP_OMM_ACTIVE_POWER_FROM_EV,		/*< active power from EV, in W */
+	OCPP_OMM_ACTIVE_POWER_TO_EV,		/*< active power to EV, in W */
+	OCPP_OMM_REACTIVE_POWER_FROM_EV,	/*< reactive power from EV, in var */
+	OCPP_OMM_REACTIVE_POWER_TO_EV,		/*< reactive power to EV, in var */
+	OCPP_OMM_POWERLINE_FREQ,		/*< powerline frequency, in Hz */
+	OCPP_OMM_POWER_FACTOR,			/*< power factor of supply */
+	OCPP_OMM_POWER_MAX_OFFERED_TO_EV,	/*< maximum power offered to EV, in W */
+	OCPP_OMM_FAN_SPEED,			/*< fan speed, in rpm */
+	OCPP_OMM_CHARGING_PERCENT,		/*< charging percentage */
+	OCPP_OMM_TEMPERATURE,			/*< temperature inside charge point, in Celsius */
+	OCPP_OMM_VOLTAGE_AC_RMS,		/*< AC RMS supply voltage, in V */
+
+	OCPP_OMM_END
+};
+
+/** @brief OCPP user callback notification/request of input/output values
+ *         union member should be accessed with enum value ocpp_notify_reason
+ *         correspondingly.
+ *         e.g. callback reason is OCPP_USR_GET_METER_VALUE, struct meter_val
+ *              is valid
+ */
+union ocpp_io_value {
+
+	struct {
+		/** Input to user, requested connector_id or 0 - main meter */
+		int id_con;
+
+		/** Input to user, measurand */
+		enum ocpp_meter_measurand mes;
+
+		 /** To be filled by user, value as string */
+		char val[CISTR50];
+	} meter_val;
+
+	struct {
+		char idtag[CISTR50];	/**< Input to user */
+
+		/** Input to user(optional). connector id -1 means invalid */
+		int id_con;
+	} start_charge;
+
+	struct {
+		int id_con;	/**< Input to user, to stop charging connector */
+	} stop_charge;
+
+	struct {
+		int id_con;	/**< Input to user, to unlock connector id. */
+	} unlock_con;
+};
+
+/** @brief Parameters for ocpp_init information about Charge Point (CP)
+ *         all are string literal except num_of_con
+ */
+struct ocpp_cp_info {
+	char *model;		/**< Charge Point (CP) model */
+	char *vendor;		/**< CP vendor */
+
+	int num_of_con;		/**< Max. number of connector supports */
+
+	/** optional fields */
+	char *sl_no;		/**< CP serial number */
+	char *box_sl_no;	/**< Box serial number */
+	char *fw_ver;		/**< Firmware version */
+	char *iccid;		/**< ICC ID */
+	char *imsi;		/**< IMSI */
+	char *meter_sl_no;	/**< Main power meter serial number */
+	char *meter_type;	/**< Main power meter type */
+};
+
+/** @brief Parameters for ocpp_init information about central system (CS) */
+struct ocpp_cs_info {
+	char *cs_ip;	/**< Central system IP address */
+	char *ws_url;	/**< Websocket url exclude ipaddr & port */
+	int port;	/**< Central system port number */
+	sa_family_t sa_family; /**< IP protocol family type 4/6 */
+};
+
+/** @brief Parameters opaque session handle for ocpp_* API */
+typedef void *ocpp_session_handle_t;
+
+/**
+ * @brief Asynchronous event notification callback registered by the
+ *        application. advised callback should not be hold for longer time
+ *        to unblock the ocpp protocol stack/lib.
+ *
+ * @param[in] reason for callback invoked.
+ * @param[in] io reffered corresponding to reason.
+ * @param[in] user_data passed on ocpp_init.
+ *
+ * @return 0 or a negative error code (errno.h)
+ */
+typedef int (*ocpp_user_notify_callback_t)(enum ocpp_notify_reason reason,
+					   union ocpp_io_value *io,
+					   void *user_data);
+
+/**
+ * @brief OCPP library init.
+ *
+ * @param[in] cpi Charge Point information
+ * @param[in] csi Central System information
+ * @param[in] cb user register callback
+ * @param[in] user_data same reference will be passed on callback
+ *
+ * @return 0 on success or a negative error code (errno.h) indicating reason of failure
+ *
+ * @note Must be called before any other ocpp API
+ */
+int ocpp_init(struct ocpp_cp_info *cpi,
+	      struct ocpp_cs_info *csi,
+	      ocpp_user_notify_callback_t cb,
+	      void *user_data);
+
+/**
+ * @brief API to request a new Session
+ *
+ * @param[out] hndl a valid opaque handle
+ *
+ * @return 0 on success or a negative error code (errno.h) indicating reason of failure
+ *
+ * @note Each connector should open unique session after ocpp_init and
+ * prior to anyother ocpp_* request message api
+ */
+int ocpp_session_open(ocpp_session_handle_t *hndl);
+
+/**
+ * @brief API to close a Session
+ *
+ * @param[in] hndl a handle received from session open
+ */
+void ocpp_session_close(ocpp_session_handle_t hndl);
+
+/**
+ * @brief Authorize request call to CS to get validity of idtag
+ *
+ * @param[in] hndl session handle
+ * @param[in] idtag (string literal) to get authorize validity
+ * @param[out] status authorization status
+ * @param[in] timeout_ms in msec
+ *
+ * @return 0 on success or a negative error code (errno.h) indicating reason of failure
+ */
+int ocpp_authorize(ocpp_session_handle_t hndl,
+		   char *idtag,
+		   enum ocpp_auth_status *status,
+		   uint32_t timeout_ms);
+
+/**
+ * @brief Notify transaction start to CS
+ *
+ * @param[in] hndl session handle
+ * @param[in] Wh energy meter reading of this connector
+ * @param[in] conn_id connector id should be > 0 and sequential number
+ * @param[in] timeout_ms timeout in msec
+ *
+ * @return: 0 on success
+ *	    EACCES - not authorized, should follow the stop charging process
+ *	    a negative error code (errno.h) indicating reason of failure
+ */
+int ocpp_start_transaction(ocpp_session_handle_t hndl,
+			   int Wh,
+			   uint8_t conn_id,
+			   uint32_t timeout_ms);
+
+/**
+ * @brief Notify transaction stopped to CS
+ *
+ * @param[in] hndl session handle
+ * @param[in] Wh energy meter reading of this connector
+ * @param[in] timeout_ms timeout in msec
+ *
+ * @return 0 on success or a negative error code (errno.h) indicating reason of failure
+ */
+int ocpp_stop_transaction(ocpp_session_handle_t hndl,
+			  int Wh,
+			  uint32_t timeout_ms);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* ZEPHYR_INCLUDE_NET_OCPP_H_ */
+
+/**@}  */

subsys/net/lib/CMakeLists.txt

@@ -19,6 +19,7 @@ add_subdirectory_ifdef(CONFIG_NET_TRICKLE            trickle)
 add_subdirectory_ifdef(CONFIG_NET_DHCPV6             dhcpv6)
 add_subdirectory_ifdef(CONFIG_PROMETHEUS             prometheus)
 add_subdirectory_ifdef(CONFIG_WIFI_CREDENTIALS       wifi_credentials)
+add_subdirectory_ifdef(CONFIG_OCPP ocpp)
 
 if (CONFIG_NET_DHCPV4 OR CONFIG_NET_DHCPV4_SERVER)
   add_subdirectory(dhcpv4)

subsys/net/lib/Kconfig

@@ -25,6 +25,8 @@ source "subsys/net/lib/socks/Kconfig"
 
 source "subsys/net/lib/sntp/Kconfig"
 
+source "subsys/net/lib/ocpp/Kconfig"
+
 endmenu
 
 menu "Network Libraries"

subsys/net/lib/ocpp/CMakeLists.txt

@@ -0,0 +1,11 @@
+# SPDX-License-Identifier: Apache-2.0
+
+zephyr_library()
+
+zephyr_library_sources(
+    ocpp.c
+    core.c
+    key_mgmt.c
+    ocpp_j.c
+    ocpp_wamp_rpc.c
+)

subsys/net/lib/ocpp/Kconfig

@@ -0,0 +1,83 @@
+# Copyright (c) 2025 Linumiz GmbH
+# SPDX-License-Identifier: Apache-2.0
+
+config OCPP
+	bool "Open Charge Point Protocol [EXPERIMENTAL]"
+	depends on JSON_LIBRARY
+	depends on WEBSOCKET_CLIENT
+	select EXPERIMENTAL
+	help
+	  This option enables the open charge point protocol library
+
+if OCPP
+
+module=OCPP
+module-dep=NET_LOG
+module-str=Log level for OCPP
+module-help=Enables ocpp debug messages.
+source "subsys/net/Kconfig.template.log_config.net"
+
+config OCPP_INT_THREAD_STACKSIZE
+	int "OCPP internal thread stacksize"
+	default 4096
+	help
+	   OCPP internal thread stacksize
+
+config OCPP_WSREADER_THREAD_STACKSIZE
+	int "OCPP websocket reader thread stacksize"
+	default 4096
+	help
+	   OCPP websocket reader thread stacksize
+
+config OCPP_RECV_BUFFER_SIZE
+	int "OCPP websocket recive buffer size"
+	default 2048
+	help
+	   OCPP websocket recive buffer size
+
+config OCPP_INTERNAL_MSGQ_CNT
+	int "OCPP internal message queue count"
+	default 10
+	help
+	   Messages communication between websocket reader and internal
+	   process thread
+
+config OCPP_MSG_JSON
+	bool "PDU message format as JSON"
+	default y
+	help
+	   If enabled y, then the Charge Point and Central System PDU message
+	   format as JSON
+
+config OCPP_PROFILE_SMART_CHARGE
+	bool "OCPP profile smart charging"
+	help
+	  Enables the OCPP library to support the Smart Charging profile
+	  functionality. Charge Point may support this profile as optional.
+
+config OCPP_PROFILE_REMOTE_TRIG
+	bool "OCPP profile remote trigger"
+	help
+	  Enables the OCPP library to support the Remote Trigger
+	  functionality. Charge Point may support this profile as optional.
+
+config OCPP_PROFILE_RESERVATION
+	bool "OCPP profile reservation"
+	help
+	  Enables the OCPP library to support the Profile Reservation
+	  functionality. Charge Point may support this profile as optional.
+
+config OCPP_PROFILE_LOCAL_AUTH_LIST
+	bool "OCPP profile local authorization list"
+	help
+	  Enables the OCPP library to support the Local Authorization List
+	  functionality. Stores IdTag and its validity information in the
+	  persistent stroage. Charge Point may support this as optional.
+
+config OCPP_PROFILE_FIRMWARE_MGNT
+	bool "OCPP profile firmware management"
+	help
+	  Enables the OCPP library to support the Firmware Management of
+	  Charge Point as optional profile.
+
+endif # OCPP