/*
 * This file is part of the PCEPlib, a PCEP protocol library.
 *
 * Copyright (C) 2020 Volta Networks https://voltanet.io/
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <https://www.gnu.org/licenses/>.
 *
 * Author : Brady Johnson <brady@voltanet.io>
 *
 */


#ifndef INCLUDE_PCEPSESSIONLOGIC_H_
#define INCLUDE_PCEPSESSIONLOGIC_H_

#include <stdbool.h>
#include <netinet/tcp.h>

#include "pcep_msg_encoding.h"
#include "pcep_socket_comm.h"
#include "pcep_msg_objects.h"
#include "pcep_msg_tools.h"
#include "pcep_timers.h"
#include "pcep_utils_queue.h"
#include "pcep_utils_memory.h"

#define PCEP_TCP_PORT 4189

typedef struct pcep_configuration_ {
	/* These are the configuration values that will
	 * be sent to the PCE in the PCEP Open message */
	int keep_alive_seconds;
	int dead_timer_seconds;
	int dead_timer_pce_negotiated_seconds; /* Config data negotiated with
						  PCE */
	int keep_alive_pce_negotiated_timer_seconds; /* Config data negotiated
							with PCE */
	int request_time_seconds;

	/* These are the acceptable ranges of values received by
	 * the PCE in the initial PCEP Open Message. If a value is
	 * received outside of these ranges, then the Open message
	 * will be rejected. */
	int min_keep_alive_seconds;
	int max_keep_alive_seconds;
	int min_dead_timer_seconds;
	int max_dead_timer_seconds;

	/* If more than this many unknown messages/requests are received
	 * per minute, then the session will be closed. */
	int max_unknown_messages;
	int max_unknown_requests;

	/* Maximum amount of time to wait to connect to the
	 * PCE TCP socket before failing, in milliseconds. */
	uint32_t socket_connect_timeout_millis;

	/* Set if the PCE/PCC will support stateful PCE LSP Updates
	 * according to RCF8231, section 7.1.1, defaults to true.
	 * Will cause an additional TLV to be sent from the PCC in
	 * the PCEP Open */
	bool support_stateful_pce_lsp_update;

	/* RFC 8281: I-bit, the PCC allows instantiation of an LSP by a PCE */
	bool support_pce_lsp_instantiation;

	/* RFC 8232: S-bit, the PCC will include the LSP-DB-VERSION
	 * TLV in each LSP object */
	bool support_include_db_version;

	/* Only set if support_include_db_version is true and if the LSP-DB
	 * survived a restart and is available. If this has a value other than
	 * 0, then a LSP-DB-VERSION TLV will be sent in the OPEN object. This
	 * value will be copied over to the pcep_session upon init. */
	uint64_t lsp_db_version;

	/* RFC 8232: T-bit, the PCE can trigger resynchronization of
	 * LSPs at any point in the life of the session */
	bool support_lsp_triggered_resync;

	/* RFC 8232: D-bit, the PCEP speaker allows incremental (delta)
	 * State Synchronization */
	bool support_lsp_delta_sync;

	/* RFC 8232: F-bit, the PCE SHOULD trigger initial (first)
	 * State Synchronization */
	bool support_pce_triggered_initial_sync;

	/* draft-ietf-pce-segment-routing-16: Send a SR PCE Capability
	 * sub-TLV in a Path Setup Type Capability TLV with a PST = 1,
	 * Path is setup using SR TE. */
	bool support_sr_te_pst;
	/* Used in the SR PCE Capability sub-TLV */
	bool pcc_can_resolve_nai_to_sid;
	/* Used in the SR TE Capability sub-TLV, 0 means there are no max sid
	 * limits */
	uint8_t max_sid_depth;

	/* If set to 0, then the default 4189 PCEP port will be used */
	uint16_t dst_pcep_port;

	/* If set to 0, then the default 4189 PCEP port will be used.
	 * This is according to the RFC5440, Section 5 */
	uint16_t src_pcep_port;

	union src_ip {
		struct in_addr src_ipv4;
		struct in6_addr src_ipv6;
	} src_ip;
	bool is_src_ipv6;

	struct pcep_versioning *pcep_msg_versioning;

	char tcp_authentication_str[PCEP_MD5SIG_MAXKEYLEN];
	bool is_tcp_auth_md5; /* true: RFC 2385, false: RFC 5925 */

} pcep_configuration;


typedef enum pcep_session_state_ {
	SESSION_STATE_UNKNOWN = 0,
	SESSION_STATE_INITIALIZED = 1,
	SESSION_STATE_PCEP_CONNECTING = 2,
	SESSION_STATE_PCEP_CONNECTED = 3

} pcep_session_state;


typedef struct pcep_session_ {
	int session_id;
	pcep_session_state session_state;
	int timer_id_open_keep_wait;
	int timer_id_open_keep_alive;
	int timer_id_dead_timer;
	int timer_id_keep_alive;
	bool pce_open_received;
	bool pce_open_rejected;
	bool pce_open_accepted;
	bool pce_open_keep_alive_sent;
	bool pcc_open_rejected;
	bool pcc_open_accepted;
	bool stateful_pce;
	time_t time_connected;
	uint64_t lsp_db_version;
	queue_handle *num_unknown_messages_time_queue;
	/* set this flag when finalizing the session */
	bool destroy_session_after_write;
	pcep_socket_comm_session *socket_comm_session;
	/* Configuration sent from the PCC to the PCE */
	pcep_configuration pcc_config;
	/* Configuration received from the PCE, to be used in the PCC */
	pcep_configuration pce_config;
	struct counters_group *pcep_session_counters;

} pcep_session;


typedef enum pcep_event_type {
	MESSAGE_RECEIVED = 0,
	PCE_CLOSED_SOCKET = 1,
	PCE_SENT_PCEP_CLOSE = 2,
	PCE_DEAD_TIMER_EXPIRED = 3,
	PCE_OPEN_KEEP_WAIT_TIMER_EXPIRED = 4,
	PCC_CONNECTED_TO_PCE = 100,
	PCC_CONNECTION_FAILURE = 101,
	PCC_PCEP_SESSION_CLOSED = 102,
	PCC_RCVD_INVALID_OPEN = 103,
	PCC_SENT_INVALID_OPEN = 104,
	PCC_RCVD_MAX_INVALID_MSGS = 105,
	PCC_RCVD_MAX_UNKOWN_MSGS = 106

} pcep_event_type;


typedef struct pcep_event {
	enum pcep_event_type event_type;
	time_t event_time;
	struct pcep_message *message;
	pcep_session *session;

} pcep_event;

typedef void (*pceplib_pcep_event_callback)(void *cb_data, pcep_event *);
typedef int (*pthread_create_callback)(pthread_t *pthread_id,
				       const pthread_attr_t *attr,
				       void *(*start_routine)(void *),
				       void *data, const char *thread_name);


typedef struct pcep_event_queue {
	/* The event_queue and event_callback are mutually exclusive.
	 * If the event_callback is configured, then the event_queue
	 * will not be used. */
	queue_handle *event_queue;
	pthread_mutex_t event_queue_mutex;
	pceplib_pcep_event_callback event_callback;
	void *event_callback_data;

} pcep_event_queue;


typedef struct pceplib_infra_config {
	/* Memory infrastructure */
	void *pceplib_infra_mt;
	void *pceplib_messages_mt;
	pceplib_malloc_func malloc_func;
	pceplib_calloc_func calloc_func;
	pceplib_realloc_func realloc_func;
	pceplib_strdup_func strdup_func;
	pceplib_free_func free_func;

	/* External Timer and Socket infrastructure */
	void *external_infra_data;
	ext_timer_create timer_create_func;
	ext_timer_cancel timer_cancel_func;
	ext_socket_write socket_write_func;
	ext_socket_read socket_read_func;

	/* External pcep_event infrastructure */
	pceplib_pcep_event_callback pcep_event_func;

	/* Callback to create pthreads */
	pthread_create_callback pthread_create_func;

} pceplib_infra_config;

/*
 * Counters Sub-groups definitions
 */
typedef enum pcep_session_counters_subgroup_ids {
	COUNTER_SUBGROUP_ID_RX_MSG = 0,
	COUNTER_SUBGROUP_ID_TX_MSG = 1,
	COUNTER_SUBGROUP_ID_RX_OBJ = 2,
	COUNTER_SUBGROUP_ID_TX_OBJ = 3,
	COUNTER_SUBGROUP_ID_RX_SUBOBJ = 4,
	COUNTER_SUBGROUP_ID_TX_SUBOBJ = 5,
	COUNTER_SUBGROUP_ID_RX_RO_SR_SUBOBJ = 6,
	COUNTER_SUBGROUP_ID_TX_RO_SR_SUBOBJ = 7,
	COUNTER_SUBGROUP_ID_RX_TLV = 8,
	COUNTER_SUBGROUP_ID_TX_TLV = 9,
	COUNTER_SUBGROUP_ID_EVENT = 10

} pcep_session_counters_subgroup_ids;

bool run_session_logic(void);
bool run_session_logic_with_infra(pceplib_infra_config *infra_config);

bool run_session_logic_wait_for_completion(void);

bool stop_session_logic(void);

/* Uses the standard PCEP TCP dest port = 4189 and an ephemeral src port.
 * To use a specific dest or src port, set them other than 0 in the
 * pcep_configuration. */
pcep_session *create_pcep_session(pcep_configuration *config,
				  struct in_addr *pce_ip);
pcep_session *create_pcep_session_ipv6(pcep_configuration *config,
				       struct in6_addr *pce_ip);

/* Send a PCEP close for this pcep_session */
void close_pcep_session(pcep_session *session);
void close_pcep_session_with_reason(pcep_session *session,
				    enum pcep_close_reason);

/* Destroy the PCEP session, a PCEP close should have
 * already been sent with close_pcep_session() */
void destroy_pcep_session(pcep_session *session);

void pcep_session_cancel_timers(pcep_session *session);

/* Increments transmitted message counters, additionally counters for the
 * objects, sub-objects, and TLVs in the message will be incremented.  Received
 * counters are incremented internally. */
void increment_message_tx_counters(pcep_session *session,
				   struct pcep_message *message);

bool session_exists(pcep_session *session);

#endif /* INCLUDE_PCEPSESSIONLOGIC_H_ */