buf.h

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#ifndef BUF_H__
#define BUF_H__

#include "ack.h"

struct buffer_t {
  // This indicates the last packet sent to the kernel.
  // It is used when deciding whether a received packet 
  // is new or just resent because of a lost ack
  int ip_buf_rcv_pos;
  char *ip_buf_rcv;
  int ip_buf_send_pos;
  char *ip_buf_send;
  // The packets we sent and we're waiting for acks
  struct ack *ack_sent;
  // The packets we rcvd and we have to confirm
  struct ack *ack_rcvd;
  // The data we reveived and that has to go to the kernel
  struct ack *rcvd;
  // The data we have to send
  struct ack *send;
  // The net-device structure
  struct net_device *dev;
};

/**
 * @short initialise the buffers
 *
 * Initialises enough memory for a couple of IP-packets...
 *
 * @param buf where all the stuff shall be stored
 */
void buf_init( struct buffer_t *buf );


/**
 * Clean up the buffers
 */
void buf_cleanup( struct buffer_t *buf );

 
/**
 * @short update the references
 *
 * When receiving an acknowledge over the air, we can delete some
 * references from our table...
 *
 * @param buf the buffer-structure
 * @param pack what to remove
 */
void buf_update_ack_sent( struct buffer_t *buf, struct rf_packet *pack );


/**
 * @short inserts a rf-packet in the buffer
 *
 * Puts together received data that comes from the rf-interface.
 * Also inserts acks in the list and calls the kernel-rx 
 * function if a packet has been received successfully.
 *
 * @param buf the buffer-structure
 * @param pack the received packet
 */
void buf_rf_to_net( struct buffer_t *buf, struct rf_packet *pack );


/**
 * @short prepare a packet over the air
 *
 */
void buf_net_to_rf( struct buffer_t *buf, char *packet, int len );


/**
 * @short copies b to a with wrap-over in the destination 
 *
 * Copies b to a and takes care about an eventual overflow in the
 * destination block. It then returns the new position.
 *
 * @param a destination
 * @param b source
 * @param pos the position in the destination
 * @param len how many bytes
 * @param wrap the size of the destination
 * @return the new position in the destination
 */
int buf_copy_wrap_dst( void *a, void *b, int pos, int len, int wrap );

/**
 * @short copies b to a with wrap-over in the source
 *
 * Copies b to a and takes care about an eventual overflow in the
 * source block. It then returns the new position.
 *
 * @param a destination
 * @param b source
 * @param pos the position in the source
 * @param len how many bytes
 * @param wrap the size of the source
 * @return the new position in the source
 */
int buf_copy_wrap_src( void *a, void *b, int pos, int len, int wrap );



#endif