Messaging program?

I am going to attempt to create a messaging service and wondered if anyone could help and point me in the right direction. I want to use TCP and the sockets api. I need to have 2 clients that will send messages to each other, but the messages will be relayed from a server so that it can store the messages and statistics.

Any ideas or pieces of code that will be useful? I haven't tried network programming as of yet.

http://www.ecst.csuchico.edu/~beej/guide/net/ might help you with your first socket experience.

Ok this is what I have but have a few problems.

This is the server code.

Code:

---

/* server.c */

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

main()
{

  int cont,create_socket,new_socket,addrlen;
  int bufsize = 512;
  char filename [10];
  int messageno = 0;
  char *buffer = malloc(bufsize);
  struct sockaddr_in address;
  FILE *newfile;

  printf("\x1B[2J");
  if ((create_socket = socket(AF_INET,SOCK_STREAM,0)) > 0)
    printf("Socket created\n");

  address.sin_family = AF_INET;
  address.sin_addr.s_addr = INADDR_ANY;
  address.sin_port = htons(15000);
  if (bind(create_socket,(struct sockaddr *)&address,sizeof(address)) == 0)
    printf("Socket Bound\n");

  listen(create_socket,3);
  addrlen = sizeof(struct sockaddr_in);
  new_socket = accept(create_socket,(struct sockaddr *)&address,&addrlen);
  if (new_socket > 0){
      printf("The Client %s is connected...\n",inet_ntoa(address.sin_addr));
      for(cont=1;cont<5000;cont++)
        printf("\x7");
  }

  do{
      recv(new_socket,buffer,bufsize,0);
      printf("Message recieved: %s\n",buffer);
      messageno = (messageno + 1);
      printf ("Saving to file\n");
      newfile = fopen ("messages.txt", "a");
      fprintf (newfile,"%d %s \n",messageno, buffer);

  }while(strcmp(buffer,"/q")); //user ‘q’ to quit
      fclose (newfile);
  close(new_socket);
  close(create_socket);
}

---

And this is the client code.

Code:

---

/* client.c */

#include<sys/socket.h>
#include<sys/types.h>
#include<netinet/in.h>
#include<unistd.h>
#include<stdlib.h>
#include<stdio.h>
#include<arpa/inet.h>


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

  int create_socket;
  int bufsize = 160;
  char *buffer = malloc(bufsize);
  struct sockaddr_in address;
  int choice;

  void sendmess ()
            {
                      printf("\x1B[2J");
                      if ((create_socket = socket(AF_INET,SOCK_STREAM,0)) > 0)
                        printf("Socket created\n");
                      address.sin_family = AF_INET;
                      address.sin_port = htons(15000);
                      inet_pton(AF_INET,argv[1],&address.sin_addr);

                      if (connect(create_socket,(struct sockaddr *)&address,sizeof(address)) == 0)
                        printf("Connection accepted with the server %s...\n\n",inet_ntoa(address.sin_addr));

              do{
                      printf("Message to send: ");
                      gets(buffer);
                      send(create_socket,buffer,bufsize,0);


              }while (strcmp(buffer,"/q"));
              close(create_socket);
}

void recvmess ()
{
        recv(create_socket,buffer,bufsize,0);
            printf("Message recieved: %s\n",buffer);
}

do {
                        printf(" Plesae choose and option\n");
                        printf(" \n\n");
                        printf(" Press <1> to send a message\n");
                        printf(" Press <2> to receive a message\n");
                        printf (" Please enter number and hit return key: ");
                        scanf ("%d",&choice);
                        switch(choice)
                        {
                                  case 1 : sendmess(); break;
                                  case 2 : recvmess(); break;
                                  case 0 : break;
                                  default :{
                                                                printf ("\nUnknown Command\n");
                                                                printf ("hit enter to continue\n");
                                                                fflush(stdin);
                                                                getchar();
                                                  };break;
                        }
                }while (choice != 0);

}

---

When the user on a client inputs a menu option, the server thinks this is a message and receives it, I don't know how to fix this. Also I am trying to get the server to store the messages as I want more than 1 client and so that they can address messages to each other which are relayed from the server.

Any help would be appreciated.

Thanks