Chip 2011 November/CHIP_2011_11.iso/Programy/Inne/Gry/Atomic_Tanks/Atomic-Tanks-5.1.exe/src/network.cpp

C/C++ Source or Header | 2009-11-15 | 11.5 KB | 510 lines

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#ifdef NETWORK
#include <sys/types.h>
#include <sys/socket.h>
#include <sys/select.h>
#include <netdb.h>
#include <errno.h>
#include <unistd.h>
#include <pthread.h>
#endif

#include "network.h"
#include "player.h"
#include "globaldata.h"


// init the object
MESSAGE_QUEUE::MESSAGE_QUEUE()
{
   first_message = last_message = NULL;
}



// do clean up on all messages
MESSAGE_QUEUE::~MESSAGE_QUEUE()
{
   Erase_All();
}



// add a new message to the queue
// Returns true on success and false is an error occures
bool MESSAGE_QUEUE::Add(char *some_text, int to)
{
    MESSAGE *new_message;

    if (! some_text)
      return false;

    new_message = (MESSAGE *) calloc(1, sizeof(MESSAGE));
    if (! new_message)
        return false;
    new_message->text = (char *) calloc( strlen(some_text), sizeof(char) );
    if (! new_message->text)
    {
       free(new_message);
       return false;
    }

    // fill the message structure
    strcpy(new_message->text, some_text);
    new_message->to = to;
    // next is already cleared by calloc

    // empty line, create new line
    if (! first_message)
    {
       first_message = new_message;
       last_message = new_message;
    }

    else // we have a line, add it to the end
    {
       last_message->next = new_message;
       last_message = new_message;
    }
    return true;
}



// retreive a message and erase it from the queue
// returns a message on success and NULL on failure
MESSAGE *MESSAGE_QUEUE::Read()
{
   MESSAGE *my_message;

   my_message = Peek();       // grab next message
   if (my_message)
      Erase();            // clear it from the queue

   return my_message;
}



// returns a message from the queue without removing it from the line
// Returns a message on success or a NULL on failure
MESSAGE *MESSAGE_QUEUE::Peek()
{
   MESSAGE *my_message;

   // see if there is a message to get
   if ( (! first_message) || (! first_message->text) )
      return NULL;

   // we want to make a copy of the message, not just pass back a pointer
   my_message = (MESSAGE *) calloc( 1, sizeof(MESSAGE) );
   if (! my_message)
      return NULL;
   my_message->text = (char *) calloc( strlen(first_message->text), sizeof(char) );
   if (! my_message->text)
   {
      free(my_message);
      return NULL;
   }

   // we have an empty message. Now fill it
   strcpy(my_message->text, first_message->text);
   my_message->to = first_message->to;

   return my_message;
}



// Finds the next message destined "to" a given player
// This function returns the first message it finds and
// erases it. The message is returned on success or a
// NULL is returned if no message is found.
MESSAGE *MESSAGE_QUEUE::Read_To(int my_to)
{
    MESSAGE *current, *previous = NULL, *my_message = NULL;
    bool found = false;

    // search for matching to field
    current = first_message;
    while ( (current) && (! found) )
    {
       if ( current->to == my_to )
          found = true;
       else
       {
          previous = current;
          current = (MESSAGE *) current->next;
       }
    }

    if (! found)
        return NULL;

    // found match, create a copy and erase the original
    my_message = (MESSAGE *) calloc( 1, sizeof(MESSAGE));
    if (! my_message)
        return NULL;

    my_message->text = (char *) calloc( strlen(current->text), sizeof(char));
    if (! my_message->text)
    {
        free(my_message);
        return NULL;
    }

    my_message->to = current->to;
    strcpy(my_message->text, current->text);
    if (previous)
       previous->next = current->next;
    else
       first_message = (MESSAGE *) current->next;

    if (last_message == current)
        last_message = previous;

    free(current->text);
    free(current);
    return my_message;
}


// Erases the next message in the line without returning anything
void MESSAGE_QUEUE::Erase()
{
   MESSAGE *next_in_line;

   if (first_message)
   {
      next_in_line = (MESSAGE *) first_message->next;
      // clean up
      if (first_message->text)
      {
         free(first_message->text);
         first_message->text = NULL;
      }
      free(first_message);

      // see if we are at the end of the list
      if (last_message == first_message)
        last_message = next_in_line;

      first_message = next_in_line;
   }

}



// This function erases all messages in the queue.
void MESSAGE_QUEUE::Erase_All()
{
   MESSAGE *current, *coming_up;

   current = first_message;
   while (current)
   {
       coming_up = (MESSAGE *) current->next;
       if (current->text)
          free(current->text);
       free(current);
       current = coming_up;
   }

   first_message = last_message = NULL;
}





//
// Past this point we have socket functions.
//
//
#ifdef NETWORK


// Create a socket for listening. Returns a listening socket
// on success or -1 on failure.
int Setup_Server_Socket(int port)
{
   int listensocket;
   struct sockaddr_in myaddr;

   listensocket = socket(AF_INET, SOCK_STREAM, 0);
   myaddr.sin_port = htons(port);
   myaddr.sin_addr.s_addr = INADDR_ANY;
   if (bind(listensocket, (struct sockaddr *) &myaddr, sizeof(myaddr)) < 0)
   {
       printf("Bind failed: %s\n", strerror(errno));
       return -1;
   }
   if (listen(listensocket, 5))
   {
       printf("Listen failed: %s\n", strerror(errno));
       return -1;
   }

   return listensocket;
}




// Connect to a remote server. Returns -1 on failure or
// a socket (int) on success.
int Setup_Client_Socket(char *server_name, char *port)
{
   int socket_num, port_number;
   struct sockaddr_in server_address;
   struct hostent *server;

   sscanf(port, "%d", &port_number);
   socket_num = socket(AF_INET, SOCK_STREAM, 0);
   if (socket_num < 0)
      return -1;
   server = gethostbyname(server_name);
   if (! server)
      return -1;
   bzero((char *) &server_address, sizeof(server_address));
   server_address.sin_family = AF_INET;
   bcopy((char *) server->h_addr,
         (char *) &server_address.sin_addr.s_addr,
         server->h_length);
   server_address.sin_port = htons(port_number);

   // try to connect
   if ( connect(socket_num, (sockaddr *)&server_address, sizeof(server_address)) < 0)
       return -1;

   return socket_num;
}



// Accepts an incoming connection request. Returns the
// new socket connection on success or -1 on failure.
int Accept_Incoming_Connection(int my_socket)
{
   int new_connection;
   socklen_t my_length;
   struct sockaddr new_address;

   my_length = sizeof(new_address);
   new_connection = accept(my_socket, (struct sockaddr *) &new_address, &my_length);
   return new_connection;
}



// Take whatever is in the message and send it
// to a socket.
// Returns a negative number on failure. Zero and
// positive numbers indicate success.
int Send_Message(MESSAGE *mess, int to_socket)
{
    int status;
    char buffer[MAX_MESSAGE_LENGTH];

    strncpy(buffer, mess->text, MAX_MESSAGE_LENGTH);
    buffer[MAX_MESSAGE_LENGTH - 1] = '\0';
    status = write(to_socket, buffer, strlen(buffer) );
    return status;
}



// Read data from a socket and put it in a message
// Returns the message on success and NULL on failure.
// Note: the "to" field of the message is not set.
MESSAGE *Receive_Message(int from_socket)
{
  MESSAGE *my_message;
  int bytes_read;
  char buffer[MAX_MESSAGE_LENGTH];

  my_message = (MESSAGE *) calloc( 1, sizeof(MESSAGE) );
  if (! my_message)
     return NULL;

  memset(buffer, '\0', MAX_MESSAGE_LENGTH);
  bytes_read = read(from_socket, buffer, MAX_MESSAGE_LENGTH);
  if (bytes_read > 0)
  {
     buffer[MAX_MESSAGE_LENGTH - 1] = '\0';
     my_message->text = (char *) calloc( strlen(buffer), sizeof(char) );
     if (! my_message->text)
     {
         free(my_message);
         return NULL;
     }
     strcpy(my_message->text, buffer);
     return my_message;
  }
  else   // error while reading
  {
      free(my_message);
      return NULL;
  }

}



void Clean_Up_Server_Socket(int my_socket)
{
   close(my_socket);
}


void Clean_Up_Client_Socket(int my_socket)
{
   close(my_socket);
}



// This function checks the socket to see if there is data ready to
// be read. If there is data ready, then the function returns TRUE. If
// an error occures, the function returns -1. If there is no data
// and no error, the function returns FALSE.
int Check_For_Incoming_Data(int socket_number)
{
   fd_set rfds;
   struct timeval tv;
   int retval;

   FD_ZERO(&rfds);
   FD_SET(socket_number, &rfds);

   tv.tv_sec = 0;
   tv.tv_usec = 0;

   retval = select(socket_number + 1, &rfds, NULL, NULL, &tv);

   if (retval == -1)
       return -1;

   else if (retval)
       return TRUE;

   else
       return FALSE;

    return TRUE;
}




// This function checks the passed socket for errors. If the socket
// is error-free, the function returns FALSE. If an exception
// has occured, the function returns TRUE.
int Check_For_Errors(int socket_number)
{
    fd_set exds;
    struct timeval tv;
    int expval;

    FD_ZERO(&exds);
    FD_SET(socket_number, &exds);
    tv.tv_sec = 0;
    tv.tv_usec = 0;

    expval = select(socket_number + 1, NULL, NULL, &exds, &tv);

    if (expval == -1)
       return TRUE;
    else if (expval)
       return TRUE;
    else
       return FALSE;
}




// This function will probably be called as a separate thread at the
// start of the game. It will set up a listening port, accept
// incoming connections and manage them. That is, they will be
// passed on to AI players.
void *Send_And_Receive(void *all_the_data)
{
   SEND_RECEIVE_TYPE *send_receive_data = (SEND_RECEIVE_TYPE *) all_the_data;
   int server_socket, new_socket;
   int status, counter;
   GLOBALDATA *global = (GLOBALDATA *) send_receive_data->global;
   bool found;

   // set up listening socket
   server_socket = Setup_Server_Socket(send_receive_data->listening_port);
   if (server_socket == -1)
   {
      printf("Error creating listening socket.\n");
      pthread_exit(NULL);
   }

   while (! send_receive_data->shut_down)
   {
      // check for incoming connections
      status = Check_For_Incoming_Data(server_socket);
      if (status)
      {
         new_socket = Accept_Incoming_Connection(server_socket);
         printf("Accepted connection.\n");
         // give connection to AI player
         found = false;
         while ( (! found) && (counter < global->numPlayers) )
         {
              if ( ( global->players[counter]->type >= USELESS_PLAYER) &&
                   ( global->players[counter]->type <= DEADLY_PLAYER) )
              {
                  found = true;
                  global->players[counter]->server_socket = new_socket;
                  global->players[counter]->previous_type = global->players[counter]->type;
                  global->players[counter]->type = NETWORK_CLIENT;
                  printf("Assigned connection to %s\n", global->players[counter]->getName() );
              }
              else
                 counter++;
         }
         // in case we did not find a match
         if (! found)
         {
            printf("Unable to assign new connection to player.\n");
            write(new_socket, "NOROOM", strlen("NOROOM") );
            close(new_socket);
         }
      }

      // consider resting for a moment?
      usleep(10000);
   }

   // clean up everything
   printf("Cleaning up networking\n");
   Clean_Up_Server_Socket(server_socket);
   counter = 0;
   while (counter < global->numPlayers)
   {
      if (global->players[counter]->type == NETWORK_CLIENT)
      {
          write(global->players[counter]->server_socket, "CLOSE", strlen("CLOSE") );
          close(global->players[counter]->server_socket);
      }
      counter++;
   }

   pthread_exit(NULL);
}


#endif