Programming

#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <unistd.h>
#include <errno.h>
#include <netinet/in.h>
#include <sys/wait.h>
#include <signal.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netdb.h>
#include <arpa/inet.h>
void sigchld_handler(int s)
{
    while (waitpid(-1, NULL, WNOHANG) > 0);
}
void *get_in_addr(struct sockaddr *sa)
{
    if (sa->sa_family == AF_INET) {
    return &(((struct sockaddr_in *) sa)->sin_addr);
    }
    return &(((struct sockaddr_in6 *) sa)->sin6_addr);
}

char pass[100];
char pass1[100];

int main()
{
    int sockfd, new_fd, numbytes;
    struct addrinfo hints, *servinfo, *p;
    struct sockaddr_storage their_addr;
    socklen_t sin_size;
    socklen_t *size;
    struct sockaddr *names;
    int yes = 1, len = 0;
    struct sigaction sa;
    char s[INET6_ADDRSTRLEN], s1[INET6_ADDRSTRLEN];
    char name[20];
    int rv;
    memset(&hints, 0, sizeof hints);
    hints.ai_family = AF_UNSPEC;
    hints.ai_socktype = SOCK_STREAM;
    hints.ai_flags = AI_PASSIVE;
    if ((rv = getaddrinfo(NULL, "2001", &hints, &servinfo)) == -1) {
    fprintf(stderr, "getaddrinfo:%s", gai_strerror(rv));
    return 1;
    }
    printf("\n \n getaddrinfo:%d", rv);
    printf("\n------------------------------");
    for (p = servinfo; p != NULL; p = p->ai_next) {

    if ((sockfd =
         socket(p->ai_family, p->ai_socktype, p->ai_protocol)) == -1) {
        perror("server:socket");
        continue;
    }
    printf("\n server socket launched...");

    if (setsockopt(sockfd, SOL_SOCKET, SO_BROADCAST, &yes, sizeof(int))
        == -1) {
        perror("setsockopt");
        return 0;
    }
    printf("\n server setsocket option ...");

    if (bind(sockfd, p->ai_addr, p->ai_addrlen) == -1) {

        close(sockfd);
        perror("server:bind");
        continue;
    }
    printf("\n socket binded....");
    break;
    }


    if (p == NULL) {
    fprintf(stderr, "server:failed");
    return 2;
    }
    if (listen(sockfd, 10) == -1) {
    perror("listen");
    return 0;
    }
    sa.sa_handler = sigchld_handler;
    sa.sa_flags = SA_RESTART;
    if (sigaction(SIGCHLD, &sa, NULL) == -1) {
    perror("sigaction");
    exit(0);
    }
    printf("\n\nlisten to socket :%d", sockfd);

    while (1) {
    sin_size = sizeof their_addr;
    new_fd =
        accept(sockfd, (struct sockaddr *) &their_addr, &sin_size);
    printf("\n sockfd=%d new_fd=%d", sockfd, new_fd);
    if (new_fd == -1) {
        perror("accept");
        continue;
    }
    if ((rv = getpeername(new_fd, names, &sin_size)) == -1)
        perror("r");
    inet_ntop(their_addr.ss_family, names, s1, sizeof s1);
    printf("\n Peer name:%s", s);
    inet_ntop(their_addr.ss_family,
          get_in_addr((struct sockaddr *) &their_addr), s,
          sizeof s);
    printf("\n\nserver:connected %s", s);
    if (!fork()) {
        while (1) {

        len = strlen("CAN_U");

        if ((send(new_fd, "CAN_U", len + 1, 0)) == -1)
            perror("error");
        if ((strcmp(pass, "bye")) == 0) {
            close(new_fd);
            break;
        }
        pass[0] = '\0';
        if (recv(new_fd, name, sizeof name, 0) == -1)
            perror("error");
        if ((strcmp("CAN_U", name)) == 0) {
            if (send(sockfd, "YES", strlen("YES"), 0) == -1)
            perror("error5");
            printf("\nSuccess");


        }

        }
        close(new_fd);

    }
    close(new_fd);
    }
    return 0;
}