/*receiverprog.c - a server, datagram sockets*/

    #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>

    /* the port users will be connecting to */

    #define MYPORT 2500

    #define MAXBUFLEN 500

     

    int main(int argc, char *argv[])

    {

    int sockfd;

    /* my address information */

    struct sockaddr_in my_addr;

    /* connector’s address information */

    struct sockaddr_in their_addr;

    int addr_len, numbytes;

    char buf[MAXBUFLEN];

     

    if((sockfd = socket(AF_INET, SOCK_DGRAM, 0)) == -1)

    {

        perror("Server-socket() sockfd error lol!");

        exit(1);

    }

    else

        printf("Server-socket() sockfd 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;

    /* 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");

     

    addr_len = sizeof(struct sockaddr);

     

    if((numbytes = recvfrom(sockfd, buf, MAXBUFLEN-1, 0, (struct sockaddr *)&their_addr, &addr_len)) == -1)

    {

        perror("Server-recvfrom() error!");

        /*If something wrong, just exit...*/

        exit(1);

    }

    else

    {

        printf("Server-Waiting and listening...\n");

        printf("Server-recvfrom() is OK...\n");

    }

     

    printf("Server-Got packet from %s\n", inet_ntoa(their_addr.sin_addr));

    printf("Server-Packet is %d bytes long\n", numbytes);

    buf[numbytes] = '\0';

    printf("Server-Packet contains \"%s\"\n", buf);

     

    if(close(sockfd) != 0)

        printf("Server-sockfd closing failed!\n");

    else

        printf("Server-sockfd successfully closed!\n");

    return 0;

    }