\subsection*{device}
Every network device in the system is represented by a \ds{device} data
structure.
\SeeModule{include/linux/\\netdevice.h}
\begin{tscreen}\begin{verbatim}
struct device 
{

  /*
   * This is the first field of the "visible" part of this structure
   * (i.e. as seen by users in the "Space.c" file).  It is the name
   * the interface.
   */
  char                    *name;

  /* I/O specific fields                                           */
  unsigned long           rmem_end;        /* shmem "recv" end     */
  unsigned long           rmem_start;      /* shmem "recv" start   */
  unsigned long           mem_end;         /* shared mem end       */
  unsigned long           mem_start;       /* shared mem start     */
  unsigned long           base_addr;       /* device I/O address   */
  unsigned char           irq;             /* device IRQ number    */

  /* Low-level status flags. */
  volatile unsigned char  start,           /* start an operation   */
                          interrupt;       /* interrupt arrived    */
  unsigned long           tbusy;           /* transmitter busy     */
  struct device           *next;

  /* The device initialization function. Called only once.         */
  int                     (*init)(struct device *dev);

  /* Some hardware also needs these fields, but they are not part of
     the usual set specified in Space.c. */
  unsigned char           if_port;         /* Selectable AUI,TP,   */
  unsigned char           dma;             /* DMA channel          */

  struct enet_statistics* (*get_stats)(struct device *dev);

  /*
   * This marks the end of the "visible" part of the structure. All
   * fields hereafter are internal to the system, and may change at
   * will (read: may be cleaned up at will).
   */

  /* These may be needed for future network-power-down code.       */
  unsigned long           trans_start;     /* Time (jiffies) of 
                                              last transmit        */
  unsigned long           last_rx;         /* Time of last Rx      */
  unsigned short          flags;           /* interface flags (BSD)*/
  unsigned short          family;          /* address family ID    */
  unsigned short          metric;          /* routing metric       */
  unsigned short          mtu;             /* MTU value            */
  unsigned short          type;            /* hardware type        */
  unsigned short          hard_header_len; /* hardware hdr len     */
  void                    *priv;           /* private data         */

  /* Interface address info. */
  unsigned char           broadcast[MAX_ADDR_LEN];
  unsigned char           pad;               
  unsigned char           dev_addr[MAX_ADDR_LEN];  
  unsigned char           addr_len;        /* hardware addr len    */
  unsigned long           pa_addr;         /* protocol address     */
  unsigned long           pa_brdaddr;      /* protocol broadcast addr*/
  unsigned long           pa_dstaddr;      /* protocol P-P other addr*/
  unsigned long           pa_mask;         /* protocol netmask     */
  unsigned short          pa_alen;         /* protocol address len */

  struct dev_mc_list      *mc_list;        /* M'cast mac addrs     */
  int                     mc_count;        /* No installed mcasts  */
  
  struct ip_mc_list       *ip_mc_list;     /* IP m'cast filter chain */
  __u32                   tx_queue_len;    /* Max frames per queue   */
    
  /* For load balancing driver pair support */
  unsigned long           pkt_queue;       /* Packets queued       */
  struct device           *slave;          /* Slave device         */
  struct net_alias_info   *alias_info;     /* main dev alias info  */
  struct net_alias        *my_alias;       /* alias devs           */
  
  /* Pointer to the interface buffers. */
  struct sk_buff_head     buffs[DEV_NUMBUFFS];

  /* Pointers to interface service routines. */
  int                     (*open)(struct device *dev);
  int                     (*stop)(struct device *dev);
  int                     (*hard_start_xmit) (struct sk_buff *skb,
                                              struct device *dev);
  int                     (*hard_header) (struct sk_buff *skb,
                                          struct device *dev,
                                          unsigned short type,
                                          void *daddr,
                                          void *saddr,
                                          unsigned len);
  int                     (*rebuild_header)(void *eth, 
                                          struct device *dev,
                                          unsigned long raddr,
                                          struct sk_buff *skb);
  void                    (*set_multicast_list)(struct device *dev);
  int                     (*set_mac_address)(struct device *dev,
                                          void *addr);
  int                     (*do_ioctl)(struct device *dev, 
                                          struct ifreq *ifr,
                                          int cmd);
  int                     (*set_config)(struct device *dev,
                                          struct ifmap *map);
  void                    (*header_cache_bind)(struct hh_cache **hhp,
                                          struct device *dev, 
                                          unsigned short htype,
                                          __u32 daddr);
  void                    (*header_cache_update)(struct hh_cache *hh,
                                          struct device *dev,
                                          unsigned char *  haddr);
  int                     (*change_mtu)(struct device *dev,
                                          int new_mtu);
  struct iw_statistics*   (*get_wireless_stats)(struct device *dev);
};
\end{verbatim}\end{tscreen}

