/** @file
 @brief LLDP definitions and handler

 This is not to be included by the application.
 */

/*
 * Copyright (c) 2017 Intel Corporation
 *
 * SPDX-License-Identifier: Apache-2.0
 */

#ifndef ZEPHYR_INCLUDE_NET_LLDP_H_
#define ZEPHYR_INCLUDE_NET_LLDP_H_

/**
 * @brief LLDP definitions and helpers
 * @defgroup lldp Link Layer Discovery Protocol definitions and helpers
 * @ingroup networking
 * @{
 */

#ifdef __cplusplus
extern "C" {
#endif

#if defined(CONFIG_NET_LLDP)

/* LLDP Definitions */

/* According to the spec, End of LLDPDU TLV value is constant. */
#define NET_LLDP_END_LLDPDU_VALUE 0x0000

/*
 * For the Chassis ID TLV Value, if subtype is a MAC address then we must
 * use values from CONFIG_NET_LLDP_CHASSIS_ID_MAC0 through
 * CONFIG_NET_LLDP_CHASSIS_ID_MAC5. If not, we use CONFIG_NET_LLDP_CHASSIS_ID.
 *
 * FIXME: implement a similar scheme for subtype 5 (network address).
 */
#if (CONFIG_NET_LLDP_CHASSIS_ID_SUBTYPE == 4)
#define NET_LLDP_CHASSIS_ID_VALUE		\
	{					\
	  CONFIG_NET_LLDP_CHASSIS_ID_MAC0,	\
	  CONFIG_NET_LLDP_CHASSIS_ID_MAC1,	\
	  CONFIG_NET_LLDP_CHASSIS_ID_MAC2,	\
	  CONFIG_NET_LLDP_CHASSIS_ID_MAC3,	\
	  CONFIG_NET_LLDP_CHASSIS_ID_MAC4,	\
	  CONFIG_NET_LLDP_CHASSIS_ID_MAC5 	\
	}

#define NET_LLDP_CHASSIS_ID_VALUE_LEN (6)
#else
#define NET_LLDP_CHASSIS_ID_VALUE CONFIG_NET_LLDP_CHASSIS_ID
#define NET_LLDP_CHASSIS_ID_VALUE_LEN (sizeof(CONFIG_NET_LLDP_CHASSIS_ID) - 1)
#endif

/*
 * For the Port ID TLV Value, if subtype is a MAC address then we must
 * use values from CONFIG_NET_LLDP_PORT_ID_MAC0 through
 * CONFIG_NET_LLDP_PORT_ID_MAC5. If not, we use CONFIG_NET_LLDP_PORT_ID.
 *
 * FIXME: implement a similar scheme for subtype 4 (network address).
 */
#if (CONFIG_NET_LLDP_PORT_ID_SUBTYPE == 3)
#define NET_LLDP_PORT_ID_VALUE		\
	{				\
	  CONFIG_NET_LLDP_PORT_ID_MAC0,	\
	  CONFIG_NET_LLDP_PORT_ID_MAC1, \
	  CONFIG_NET_LLDP_PORT_ID_MAC2, \
	  CONFIG_NET_LLDP_PORT_ID_MAC3, \
	  CONFIG_NET_LLDP_PORT_ID_MAC4, \
	  CONFIG_NET_LLDP_PORT_ID_MAC5  \
	}

#define NET_LLDP_PORT_ID_VALUE_LEN (6)
#else
#define NET_LLDP_PORT_ID_VALUE CONFIG_NET_LLDP_PORT_ID
#define NET_LLDP_PORT_ID_VALUE_LEN (sizeof(CONFIG_NET_LLDP_PORT_ID) - 1)
#endif

/*
 * TLVs Length.
 * Note that TLVs that have a subtype must have a byte added to their length.
 */
#define NET_LLDP_CHASSIS_ID_TLV_LEN (NET_LLDP_CHASSIS_ID_VALUE_LEN + 1)
#define NET_LLDP_PORT_ID_TLV_LEN (NET_LLDP_PORT_ID_VALUE_LEN + 1)
#define NET_LLDP_TTL_TLV_LEN (2)

/*
 * Time to Live value.
 * Calculate based on section 9.2.5.22 from LLDP spec.
 *
 * FIXME: when the network interface is about to be ‘disabled’ TTL shall be set
 * to zero so LLDP Rx agents can invalidate the entry related to this node.
 */
#define NET_LLDP_TTL \
	min((CONFIG_NET_LLDP_TX_INTERVAL * CONFIG_NET_LLDP_TX_HOLD) + 1, 65535)


struct net_if;

/* TLV Types. Please refer to table 8-1 from IEEE 802.1AB standard. */
enum net_lldp_tlv_type {
	LLDP_TLV_END_LLDPDU = 0,
	LLDP_TLV_CHASSIS_ID,
	LLDP_TLV_PORT_ID,
	LLDP_TLV_TTL,
	LLDP_TLV_PORT_DESC,
	LLDP_TLV_SYSTEM_NAME,
	LLDP_TLV_SYSTEM_DESC,
	LLDP_TLV_SYSTEM_CAPABILITIES,
	LLDP_TLV_MANAGEMENT_ADDR,
	/* Types 9 - 126 are reserved. */
	LLDP_TLV_ORG_SPECIFIC = 127
};

struct net_lldp_chassis_tlv {
	uint16_t type_length;	/* 7 bits for type, 9 bits for length */
	uint8_t subtype;	/* ID subtype. */
	uint8_t value[NET_LLDP_CHASSIS_ID_VALUE_LEN];
} __packed;

struct net_lldp_port_tlv {
	uint16_t type_length;	/* 7 bits for type, 9 bits for length */
	uint8_t subtype;	/* ID subtype. */
	uint8_t value[NET_LLDP_PORT_ID_VALUE_LEN];
} __packed;

struct net_lldp_time_to_live_tlv {
	uint16_t type_length;	/* 7 bits for type, 9 bits for length */
	uint16_t ttl;		/* Time to live */
} __packed;

/*
 * LLDP Data Unit (LLDPDU) shall contain the following ordered TLVs
 * as stated in "8.2 LLDPDU format" from the Spec.
 */
struct net_lldpdu {
	struct net_lldp_chassis_tlv chassis_id;	/* Mandatory TLV */
	struct net_lldp_port_tlv port_id;	/* Mandatory TLV */
	struct net_lldp_time_to_live_tlv ttl;	/* Mandatory TLV */

#if defined(CONFIG_NET_LLDP_END_LLDPDU_TLV_ENABLED)
	/** Optional End of LLDPDU TLV. Must be set to 0x0000 always. */
	const uint16_t end_lldpdu_tlv;
#endif /* CONFIG_NET_LLDP_END_LLDPDU_TLV_ENABLED */
} __packed;

/**
 * @brief Set the LLDP data unit for a network interface.
 *
 * @param iface Network interface
 * @param lldpdu LLDP data unit struct
 *
 * @return 0 if ok, <0 if error
 */
int net_lldp_config(struct net_if *iface, const struct net_lldpdu *lldpdu);

/**
 * @brief Initialize LLDP engine.
 */
void net_lldp_init(void);

/**
 * @brief LLDP Receive packet callback
 *
 * Callback gets called upon receiving packet. It is responsible for
 * freeing packet or indicating to the stack that it needs to free packet
 * by returning correct net_verdict.
 *
 * Returns:
 *  - NET_DROP, if packet was invalid, rejected or we want the stack to free it.
 *    In this case the core stack will free the packet.
 *  - NET_OK, if the packet was accepted, in this case the ownership of the
 *    net_pkt goes to callback and core network stack will forget it.
 */
typedef enum net_verdict (*net_lldp_recv_cb_t)(struct net_if *iface,
					       struct net_pkt *pkt);

/**
 * @brief Register LLDP Rx callback function
 *
 * @param iface Network interface
 * @param cb Callback function
 *
 * @return 0 if ok, < 0 if error
 */
int net_lldp_register_callback(struct net_if *iface, net_lldp_recv_cb_t cb);

/**
 * @brief Parse LLDP packet
 *
 * @param iface Network interface
 * @param pkt Network packet
 *
 * @return Return the policy for network buffer
 */
enum net_verdict net_lldp_recv(struct net_if *iface, struct net_pkt *pkt);

#endif /* CONFIG_NET_LLDP */

#ifdef __cplusplus
}
#endif

/**
 * @}
 */

#endif /* ZEPHYR_INCLUDE_NET_LLDP_H_ */