Practical 7. Program for detection of single node failure in a network.

#include <stdio.h>

#include <stdlib.h>

#include <pthread.h>

#include <unistd.h>

#include <stdbool.h>

#define NUM_NODES 5

#define HEARTBEAT_INTERVAL 2

#define TIMEOUT 4

typedef struct Node {

    int id;

    bool alive;

    pthread_t thread;

} Node;

void* sendHeartbeat(void* arg) {

    Node* node = (Node*)arg;

    while (1) {

        sleep(HEARTBEAT_INTERVAL);

        node->alive = true;

        printf("Node %d: Sending heartbeat\n", node->id);

    }

    return NULL;

}

void* monitorNodes(void* arg) {

    Node* nodes = (Node*)arg;

    while (1) {

        sleep(TIMEOUT);

        for (int i = 0; i < NUM_NODES; i++) {

            if (!nodes[i].alive) {

                printf("Node %d: Failed\n", nodes[i].id);

            }

            nodes[i].alive = false;

        }

    }

    return NULL;

}

int main() {

    Node nodes[NUM_NODES];

    for (int i = 0; i < NUM_NODES; i++) {

        nodes[i].id = i + 1;

        nodes[i].alive = false;

        pthread_create(&nodes[i].thread, NULL, sendHeartbeat, &nodes[i]);

    }

    pthread_t monitorThread;

    pthread_create(&monitorThread, NULL, monitorNodes, nodes);

    for (int i = 0; i < NUM_NODES; i++) {

        pthread_join(nodes[i].thread, NULL);

    }

    pthread_join(monitorThread, NULL);

    return 0;

}