User:Gaurav Pruthi/Sandbox

1. include <stdio.h>
2. include <stdlib.h>
3. include <unistd.h>
4. include <string.h>
5. include <sys/types.h>
6. include <sys/socket.h>
7. include <netinet/in.h>
8. include <netdb.h>

void error(const char *msg) {

   perror(msg);
   exit(0);

}

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

   int sockfd, portno, n;
   struct sockaddr_in serv_addr;
   struct hostent *server;

   char buffer[256];
   if (argc < 3) {
      fprintf(stderr,"usage %s hostname port\n", argv[0]);
      exit(0);
   }
   portno = atoi(argv[2]);
   sockfd = socket(AF_INET, SOCK_STREAM, 0);
   if (sockfd < 0) 
       error("ERROR opening socket");
   server = gethostbyname(argv[1]);
   if (server == NULL) {
       fprintf(stderr,"ERROR, no such host\n");
       exit(0);
   }
   bzero((char *) &serv_addr, sizeof(serv_addr));
   serv_addr.sin_family = AF_INET;
   bcopy((char *)server->h_addr, 
        (char *)&serv_addr.sin_addr.s_addr,
        server->h_length);
   serv_addr.sin_port = htons(portno);
   if (connect(sockfd,(struct sockaddr *) &serv_addr,sizeof(serv_addr)) < 0) 
       error("ERROR connecting");
   printf("Please enter the message: ");
   bzero(buffer,256);
   fgets(buffer,255,stdin);
   n = write(sockfd,buffer,strlen(buffer));
   if (n < 0) 
        error("ERROR writing to socket");
   bzero(buffer,256);
   n = read(sockfd,buffer,255);
   if (n < 0) 
        error("ERROR reading from socket");
   printf("%s\n",buffer);
   close(sockfd);
   return 0;

}

=server.h

/* A simple server in the internet domain using TCP

  The port number is passed as an argument */

1. include <stdio.h>
2. include <stdlib.h>
3. include <string.h>
4. include <unistd.h>
5. include <sys/types.h>
6. include <sys/socket.h>
7. include <netinet/in.h>

void error(const char *msg) {

   perror(msg);
   exit(1);

}

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

    int sockfd, newsockfd, portno;
    socklen_t clilen;
    char buffer[256];
    struct sockaddr_in serv_addr, cli_addr;
    int n;
    if (argc < 2) {
        fprintf(stderr,"ERROR, no port provided\n");
        exit(1);
    }
    sockfd = socket(AF_INET, SOCK_STREAM, 0);
    if (sockfd < 0) 
       error("ERROR opening socket");
    bzero((char *) &serv_addr, sizeof(serv_addr));
    portno = atoi(argv[1]);
    serv_addr.sin_family = AF_INET;
    serv_addr.sin_addr.s_addr = INADDR_ANY;
    serv_addr.sin_port = htons(portno);
    if (bind(sockfd, (struct sockaddr *) &serv_addr,
             sizeof(serv_addr)) < 0) 
             error("ERROR on binding");
    listen(sockfd,5);
    clilen = sizeof(cli_addr);
    newsockfd = accept(sockfd, 
                (struct sockaddr *) &cli_addr, 
                &clilen);
    if (newsockfd < 0) 
         error("ERROR on accept");
    bzero(buffer,256);
    n = read(newsockfd,buffer,255);
    if (n < 0) error("ERROR reading from socket");
    printf("Here is the message: %s\n",buffer);
    n = write(newsockfd,"I got your message",18);
    if (n < 0) error("ERROR writing to socket");
    close(newsockfd);
    close(sockfd);
    return 0; 

}