text: #ifndef __PACKET_INTERNAL_H__
  #define __PACKET_INTERNAL_H__
  
  struct packet_mclist {
  	struct packet_mclist	*next;
  	int			ifindex;
  	int			count;
  	unsigned short		type;
  	unsigned short		alen;
  	unsigned char		addr[MAX_ADDR_LEN];
  };
  
  /* kbdq - kernel block descriptor queue */
  struct tpacket_kbdq_core {
  	struct pgv	*pkbdq;
  	unsigned int	feature_req_word;
  	unsigned int	hdrlen;
  	unsigned char	reset_pending_on_curr_blk;
  	unsigned char   delete_blk_timer;
  	unsigned short	kactive_blk_num;
  	unsigned short	blk_sizeof_priv;
  
  	/* last_kactive_blk_num:
  	 * trick to see if user-space has caught up
  	 * in order to avoid refreshing timer when every single pkt arrives.
  	 */
  	unsigned short	last_kactive_blk_num;
  
  	char		*pkblk_start;
  	char		*pkblk_end;
  	int		kblk_size;
  	unsigned int	max_frame_len;
  	unsigned int	knum_blocks;
  	uint64_t	knxt_seq_num;
  	char		*prev;
  	char		*nxt_offset;
  	struct sk_buff	*skb;
  
  	atomic_t	blk_fill_in_prog;
  
  	/* Default is set to 8ms */
  #define DEFAULT_PRB_RETIRE_TOV	(8)
  
  	unsigned short  retire_blk_tov;
  	unsigned short  version;
  	unsigned long	tov_in_jiffies;
  
  	/* timer to retire an outstanding block */
  	struct timer_list retire_blk_timer;
  };
  
  struct pgv {
  	char *buffer;
  };
  
  struct packet_ring_buffer {
  	struct pgv		*pg_vec;
  
  	unsigned int		head;
  	unsigned int		frames_per_block;
  	unsigned int		frame_size;
  	unsigned int		frame_max;
  
  	unsigned int		pg_vec_order;
  	unsigned int		pg_vec_pages;
  	unsigned int		pg_vec_len;
  
  	unsigned int __percpu	*pending_refcnt;
  
  	struct tpacket_kbdq_core	prb_bdqc;
  };
  
  extern struct mutex fanout_mutex;
  #define PACKET_FANOUT_MAX	256
  
  struct packet_fanout {
  #ifdef CONFIG_NET_NS
  	struct net		*net;
  #endif
  	unsigned int		num_members;
  	u16			id;
  	u8			type;
  	u8			flags;
  	atomic_t		rr_cur;
  	struct list_head	list;
  	struct sock		*arr[PACKET_FANOUT_MAX];
  	int			next[PACKET_FANOUT_MAX];
  	spinlock_t		lock;
  	atomic_t		sk_ref;
  	struct packet_type	prot_hook ____cacheline_aligned_in_smp;
  };
  
  struct packet_sock {
  	/* struct sock has to be the first member of packet_sock */
  	struct sock		sk;
  	struct packet_fanout	*fanout;
  	union  tpacket_stats_u	stats;
  	struct packet_ring_buffer	rx_ring;
  	struct packet_ring_buffer	tx_ring;
  	int			copy_thresh;
  	spinlock_t		bind_lock;
  	struct mutex		pg_vec_lock;
  	unsigned int		running:1,	/* prot_hook is attached*/
  				auxdata:1,
  				origdev:1,
  				has_vnet_hdr:1;
  	int			ifindex;	/* bound device		*/
  	__be16			num;
  	struct packet_mclist	*mclist;
  	atomic_t		mapped;
  	enum tpacket_versions	tp_version;
  	unsigned int		tp_hdrlen;
  	unsigned int		tp_reserve;
  	unsigned int		tp_loss:1;
  	unsigned int		tp_tx_has_off:1;
  	unsigned int		tp_tstamp;
  	struct net_device __rcu	*cached_dev;
  	int			(*xmit)(struct sk_buff *skb);
  	struct packet_type	prot_hook ____cacheline_aligned_in_smp;
  };
  
  static struct packet_sock *pkt_sk(struct sock *sk)
  {
  	return (struct packet_sock *)sk;
  }
  
  #endif
  