/*
	 * Copyright (C) 2016-2025 Red Hat, Inc.  All rights reserved.
	 *
	 * Authors: Fabio M. Di Nitto <fabbione@kronosnet.org>
	 *          Federico Simoncelli <fsimon@kronosnet.org>
	 *
	 * This software licensed under LGPL-2.0+
	 */
	
	#include "config.h"
	
	#include <pthread.h>
	#include <errno.h>
	#include <string.h>
	
	#include "internals.h"
	#include "logging.h"
	#include "threads_common.h"
	
	int shutdown_in_progress(knet_handle_t knet_h)
	{
		int savederrno = 0;
		int ret;
	
		savederrno = pthread_rwlock_rdlock(&knet_h->global_rwlock);
		if (savederrno) {
			log_err(knet_h, KNET_SUB_COMMON, "Unable to get read lock: %s",
				strerror(savederrno));
			errno = savederrno;
			return -1;
		}
	
		ret = knet_h->fini_in_progress;
	
		pthread_rwlock_unlock(&knet_h->global_rwlock);
	
		return ret;
	}
	
	static int _pmtud_reschedule(knet_handle_t knet_h)
	{

		if (knet_h->pmtud_running) {
			knet_h->pmtud_abort = 1;
	
			if (knet_h->pmtud_waiting) {
				pthread_cond_signal(&knet_h->pmtud_cond);
			}
		}
		return 0;
	}
	
	static int pmtud_reschedule(knet_handle_t knet_h)
	{
		int res;
	
		if (pthread_mutex_lock(&knet_h->pmtud_mutex) != 0) {
			log_debug(knet_h, KNET_SUB_PMTUD, "Unable to get mutex lock");
			return -1;
		}
		res = _pmtud_reschedule(knet_h);
		pthread_mutex_unlock(&knet_h->pmtud_mutex);
		return res;
	}
	
	int get_global_wrlock(knet_handle_t knet_h)
	{
		if (pmtud_reschedule(knet_h) < 0) {
			log_info(knet_h, KNET_SUB_PMTUD, "Unable to notify PMTUd to reschedule. Expect delays in executing API calls");
		}
		return pthread_rwlock_wrlock(&knet_h->global_rwlock);
	}
	
	static struct pretty_names thread_names[KNET_THREAD_MAX] =
	{
		{ "TX", KNET_THREAD_TX },
		{ "RX", KNET_THREAD_RX },
		{ "HB", KNET_THREAD_HB },
		{ "PMTUD", KNET_THREAD_PMTUD },
	#ifdef HAVE_NETINET_SCTP_H
		{ "SCTP_LISTEN", KNET_THREAD_SCTP_LISTEN },
		{ "SCTP_CONN", KNET_THREAD_SCTP_CONN },
	#endif
		{ "DST_LINK", KNET_THREAD_DST_LINK }
	};
	
	static struct pretty_names thread_status[] =
	{
		{ "unregistered", KNET_THREAD_UNREGISTERED },
		{ "registered", KNET_THREAD_REGISTERED },
		{ "started", KNET_THREAD_STARTED },
		{ "stopped", KNET_THREAD_STOPPED }
	};
	
	static const char *get_thread_status_name(uint8_t status)
	{
		unsigned int i;
	
		for (i = 0; i < KNET_THREAD_STATUS_MAX; i++) {
			if (thread_status[i].val == status) {
				return thread_status[i].name;
			}
		}
		return "unknown";
	}
	
	static const char *get_thread_name(uint8_t thread_id)
	{
		unsigned int i;
	
		for (i = 0; i < KNET_THREAD_MAX; i++) {
			if (thread_names[i].val == thread_id) {
				return thread_names[i].name;
			}
		}
		return "unknown";
	}
	
	int get_thread_flush_queue(knet_handle_t knet_h, uint8_t thread_id)
	{
		uint8_t flush;
	
		if (pthread_mutex_lock(&knet_h->threads_status_mutex) != 0) {
			log_debug(knet_h, KNET_SUB_HANDLE, "Unable to get mutex lock");
			return -1;
		}
	
		flush = knet_h->threads_flush_queue[thread_id];
	
		pthread_mutex_unlock(&knet_h->threads_status_mutex);
		return flush;
	}
	
	int set_thread_flush_queue(knet_handle_t knet_h, uint8_t thread_id, uint8_t status)
	{
		if (pthread_mutex_lock(&knet_h->threads_status_mutex) != 0) {
			log_debug(knet_h, KNET_SUB_HANDLE, "Unable to get mutex lock");
			return -1;
		}
	
		knet_h->threads_flush_queue[thread_id] = status;
	
		log_debug(knet_h, KNET_SUB_HANDLE, "Updated flush queue request for thread %s to %u",
			  get_thread_name(thread_id), status);
	
		pthread_mutex_unlock(&knet_h->threads_status_mutex);
		return 0;
	}
	
	int wait_all_threads_flush_queue(knet_handle_t knet_h)
	{
		uint8_t i = 0, found = 0;
	
		while (!found) {
			usleep(KNET_THREADS_TIMERES);
	
			if (pthread_mutex_lock(&knet_h->threads_status_mutex) != 0) {
				continue;
			}
	
			found = 1;
	
			for (i = 0; i < KNET_THREAD_MAX; i++) {
				if (knet_h->threads_flush_queue[i] == KNET_THREAD_QUEUE_FLUSHED) {
					continue;
				}
				log_debug(knet_h, KNET_SUB_HANDLE, "Checking thread: %s queue: %u",
						get_thread_name(i),
						knet_h->threads_flush_queue[i]);
				if (knet_h->threads_flush_queue[i] != KNET_THREAD_QUEUE_FLUSHED) {
					found = 0;
				}
			}
	
			pthread_mutex_unlock(&knet_h->threads_status_mutex);
		}
	
		return 0;
	}
	
	int set_thread_status(knet_handle_t knet_h, uint8_t thread_id, uint8_t status)
	{
		if (pthread_mutex_lock(&knet_h->threads_status_mutex) != 0) {
			log_debug(knet_h, KNET_SUB_HANDLE, "Unable to get mutex lock");
			return -1;
		}
	
		knet_h->threads_status[thread_id] = status;
	
		log_debug(knet_h, KNET_SUB_HANDLE, "Updated status for thread %s to %s",
			  get_thread_name(thread_id), get_thread_status_name(status));
	
		pthread_mutex_unlock(&knet_h->threads_status_mutex);
		return 0;
	}
	
	int wait_all_threads_status(knet_handle_t knet_h, uint8_t status)
	{
		uint8_t i = 0, found = 0;
	
		while (!found) {
			usleep(KNET_THREADS_TIMERES);
	
			if (pthread_mutex_lock(&knet_h->threads_status_mutex) != 0) {
				continue;
			}
	
			found = 1;
	
			for (i = 0; i < KNET_THREAD_MAX; i++) {
				if (knet_h->threads_status[i] == KNET_THREAD_UNREGISTERED) {
					continue;
				}
				log_debug(knet_h, KNET_SUB_HANDLE, "Checking thread: %s status: %s req: %s",
						get_thread_name(i),
						get_thread_status_name(knet_h->threads_status[i]),
						get_thread_status_name(status));
				if (knet_h->threads_status[i] != status) {
					found = 0;
				}
			}
	
			pthread_mutex_unlock(&knet_h->threads_status_mutex);
		}
	
		return 0;
	}
	
	void force_pmtud_run(knet_handle_t knet_h, uint8_t subsystem, uint8_t reset_mtu, uint8_t force_restart)
	{
		if (reset_mtu) {
			log_debug(knet_h, subsystem, "PMTUd has been reset to default");
			knet_h->data_mtu = calc_min_mtu(knet_h);
			if (knet_h->pmtud_notify_fn) {
				knet_h->pmtud_notify_fn(knet_h->pmtud_notify_fn_private_data,
							knet_h->data_mtu);
			}
		}
	
		/*
		 * we can only try to take a lock here. This part of the code
		 * can be invoked by any thread, including PMTUd that is already
		 * holding a lock at that stage.
		 * If PMTUd is holding the lock, most likely it is already running
		 * and we don't need to notify it back.
		 */
		if (!pthread_mutex_trylock(&knet_h->pmtud_mutex)) {
			if (!knet_h->pmtud_running) {
				if (!knet_h->pmtud_forcerun) {
					log_debug(knet_h, subsystem, "Notifying PMTUd to rerun");
					knet_h->pmtud_forcerun = 1;
				}
			} else {
				if (force_restart) {
					if (_pmtud_reschedule(knet_h) < 0) {
						log_info(knet_h, KNET_SUB_PMTUD, "Unable to notify PMTUd to reschedule. A joining node may struggle to connect properly");
					}
				}
			}
			pthread_mutex_unlock(&knet_h->pmtud_mutex);
		}
	}