serverudp.c

UDP client and server!!!

    /*******************udpserver.c*****************/

    /* Header files needed to use the sockets API. */

    /* File contain Macro, Data Type and Structure */

    /* definitions along with Function prototypes. */

    /* header files */

    #include <stdio.h>

    #include <stdlib.h>

    #include <string.h>

    #include <sys/types.h>

    #include <sys/socket.h>

    #include <netinet/in.h>

    #include <arpa/inet.h>

    /* Server's port number, listen at 3333 */

    #define SERVPORT 3333

     

    /* Run the server without argument */

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

    {

    /* Variable and structure definitions. */

    int sd, rc;

    struct sockaddr_in serveraddr, clientaddr;

    int clientaddrlen = sizeof(clientaddr);

    int serveraddrlen = sizeof(serveraddr);

    char buffer[100];

    char *bufptr = buffer;

    int buflen = sizeof(buffer);

     

    /* The socket() function returns a socket */

    /* descriptor representing an endpoint. */

    /* The statement also identifies that the */

    /* INET (Internet Protocol) address family */

    /* with the UDP transport (SOCK_DGRAM) will */

    /* be used for this socket. */

    /******************************************/

    /* get a socket descriptor */

    if((sd = socket(AF_INET, SOCK_DGRAM, 0)) < 0)

    {

    perror("UDP server - socket() error");

    exit(-1);

    }

    else

    printf("UDP server - socket() is OK\n");

     

    printf("UDP server - try to bind...\n");

     

    /* After the socket descriptor is received, */

    /* a bind() is done to assign a unique name */

    /* to the socket. In this example, the user */

    /* set the s_addr to zero. This allows the */

    /* system to connect to any client that uses */

    /* port 3333. */

    /********************************************/

    /* bind to address */

    memset(&serveraddr, 0x00, serveraddrlen);

    serveraddr.sin_family = AF_INET;

    serveraddr.sin_port = htons(SERVPORT);

    serveraddr.sin_addr.s_addr = htonl(INADDR_ANY);

    if((rc = bind(sd, (struct sockaddr *)&serveraddr, serveraddrlen)) < 0)

    {

    perror("UDP server - bind() error");

    close(sd);

    /* If something wrong with socket(), just exit lol */

    exit(-1);

    }

    else

    printf("UDP server - bind() is OK\n");

     

    printf("Using IP %s and port %d\n", inet_ntoa(serveraddr.sin_addr), SERVPORT);

    printf("UDP server - Listening...\n");

     

    /* Use the recvfrom() function to receive the */

    /* data. The recvfrom() function waits */

    /* indefinitely for data to arrive. */

    /************************************************/

    /* This example does not use flags that control */

    /* the reception of the data. */

    /************************************************/

    /* Wait on client requests. */
    int counter = 0;
    do{
        
    rc = recvfrom(sd, bufptr, buflen, 0, (struct sockaddr *)&clientaddr, &clientaddrlen);

    if(rc < 0)

    {

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

    close(sd);

    exit(-1);

    }

    else

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

     

    printf("UDP Server received the following:\n \"%s\" message\n", bufptr);

    printf("from port %d and address %s.\n", ntohs(clientaddr.sin_port),

    inet_ntoa(clientaddr.sin_addr));

     

    /* Send a reply by using the sendto() function. */

    /* In this example, the system echoes the received */

    /* data back to the client. */

    /************************************************/

    /* This example does not use flags that control */

    /* the transmission of the data */

    /************************************************/

    /* Send a reply, just echo the request */

    printf("UDP Server replying to the UDP client...\n");

    rc = sendto(sd, bufptr, buflen, 0, (struct sockaddr *)&clientaddr, clientaddrlen);

    if(rc < 0)

    {

    perror("UDP server - sendto() error");

    close(sd);

    exit(-1);

    }

    else

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

    }while(strcmp(buffer, "quit")!= 0);

    /* When the data has been sent, close() the */

    /* socket descriptor. */

    /********************************************/

    /* close() the socket descriptor. */

    close(sd);

    exit(0);

    }