TCP Server Client

This TCP server client provides the time requested by Client from Server.
It can be modified to send and receive messages too.

Here's a picture how the connections are set up.

TCP Server Client Connection SetUp

//simpleserver.c

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <errno.h>
#include <string.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <sys/wait.h>
#include <signal.h>
#include <time.h>

/* the port users will be connecting to */
#define MYPORT 3490
/* how many pending connections queue will hold */
#define BACKLOG 10

void sigchld_handler(int s)
{
    while(wait(NULL) > 0);
}

int main(int argc, char *argv[ ])
{
    /* listen on sock_fd, new connection on new_fd */
    int sockfd, new_fd;
    time_t ticks;
    char buf[300];
    /* my address information */
    struct sockaddr_in my_addr;
    /* connector.s address information */
    struct sockaddr_in their_addr;
    int sin_size;
    struct sigaction sa;
    int yes = 1;

    if ((sockfd = socket(AF_INET, SOCK_STREAM, 0)) == -1)
    {
        perror("Server-socket() error lol!");
        exit(1);
    }
    else
        printf("Server-socket() sockfd is OK...\n");

    if (setsockopt(sockfd, SOL_SOCKET, SO_REUSEADDR, &yes, sizeof(int)) == -1)
    {
        perror("Server-setsockopt() error lol!");
        exit(1);
    }
    else
        printf("Server-setsockopt is OK...\n");

    /* host byte order */
    my_addr.sin_family = AF_INET;
    /* short, network byte order */
    my_addr.sin_port = htons(MYPORT);
    /* automatically fill with my IP */
    my_addr.sin_addr.s_addr = INADDR_ANY;

    printf("Server-Using %s and port %d...\n", inet_ntoa(my_addr.sin_addr), MYPORT);

    /* zero the rest of the struct */
    memset(&(my_addr.sin_zero), '\0', 8);

    if(bind(sockfd, (struct sockaddr *)&my_addr, sizeof(struct sockaddr)) == -1)
    {
        perror("Server-bind() error");
        exit(1);
    }
    else
        printf("Server-bind() is OK...\n");

    if(listen(sockfd, BACKLOG) == -1)
    {
        perror("Server-listen() error");
        exit(1);
    }
    printf("Server-listen() is OK...Listening...\n");

    /* clean all the dead processes */
    sa.sa_handler = sigchld_handler;
    sigemptyset(&sa.sa_mask);
    sa.sa_flags = SA_RESTART;

    if(sigaction(SIGCHLD, &sa, NULL) == -1)
    {
        perror("Server-sigaction() error");
        exit(1);
    }
    else
        printf("Server-sigaction() is OK...\n");

    /* accept() loop */
    while(1)
    {
        sin_size = sizeof(struct sockaddr_in);
        if((new_fd = accept(sockfd, (struct sockaddr *)&their_addr, &sin_size)) == -1)
        {
            perror("Server-accept() error");
            continue;
        }
        else
            printf("Server-accept() is OK...\n");
        printf("Server-new socket, new_fd is OK...\n");
        printf("Server: Got connection from %s\n", inet_ntoa(their_addr.sin_addr));

        /* this is the child process */
        if(!fork())
        {
            /* child doesn.t need the listener */
            close(sockfd);
            ticks = time(NULL);
            snprintf(buf, sizeof(buf), "%.24s\r\n", ctime(&ticks));
             
            if(send(new_fd,buf, sizeof(buf), 0) == -1)
                perror("Server-send() error lol!");
            close(new_fd);
            exit(0);
        }
        else
            printf("Server-send is OK...!\n");

        /* parent doesn.t need this*/
        close(new_fd);
        printf("Server-new socket, new_fd closed successfully...\n");
    }
    return 0;
}

// simpleclient.c

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <errno.h>
#include <string.h>
#include <netdb.h>
#include <sys/types.h>
#include <netinet/in.h>
#include <sys/socket.h>

// the port client will be connecting to
#define PORT 3490
// max number of bytes we can get at once
#define MAXDATASIZE 300

int main(int argc, char *argv[])
{
    int sockfd, numbytes;
    char buf[MAXDATASIZE];
    struct hostent *he;
// connector.s address information
    struct sockaddr_in their_addr;

// if no command line argument supplied
    if(argc != 2)
    {
        fprintf(stderr, "Client-Usage: %s the_client_hostname\n", argv[0]);
// just exit
        exit(1);
    }

// get the host info
    if((he=gethostbyname(argv[1])) == NULL)
    {
        perror("gethostbyname()");
        exit(1);
    }
    else
        printf("Client-The remote host is: %s\n", argv[1]);

    if((sockfd = socket(AF_INET, SOCK_STREAM, 0)) == -1)
    {
        perror("socket()");
        exit(1);
    }
    else
        printf("Client-The socket() sockfd is OK...\n");

// host byte order
    their_addr.sin_family = AF_INET;
// short, network byte order
    printf("Server-Using %s and port %d...\n", argv[1], PORT);
    their_addr.sin_port = htons(PORT);
    their_addr.sin_addr = *((struct in_addr *)he->h_addr);
// zero the rest of the struct
    memset(&(their_addr.sin_zero), '\0', 8);

    if(connect(sockfd, (struct sockaddr *)&their_addr, sizeof(struct sockaddr)) == -1)
    {
        perror("connect()");
        exit(1);
    }
    else
        printf("Client-The connect() is OK...\n");

    if((numbytes = recv(sockfd, buf, MAXDATASIZE-1, 0)) == -1)
    {
        perror("recv()");
        exit(1);
    }
    else
        printf("Client-The recv() is OK...\n");

    buf[numbytes] = '\0';
    printf("Client-Received: %s", buf);

    printf("Client-Closing sockfd\n");
    close(sockfd);
    return 0;
}