inet: frags: enum the flag definitions and add descriptions

	int			low_thresh;

};

/**

 * fragment queue flags

 *

 * @INET_FRAG_FIRST_IN: first fragment has arrived

 * @INET_FRAG_LAST_IN: final fragment has arrived

 * @INET_FRAG_COMPLETE: frag queue has been processed and is due for destruction

 * @INET_FRAG_EVICTED: frag queue is being evicted

 */

enum {

	INET_FRAG_FIRST_IN	= BIT(0),

	INET_FRAG_LAST_IN	= BIT(1),

	INET_FRAG_COMPLETE	= BIT(2),

	INET_FRAG_EVICTED	= BIT(3)

};

/**

 * struct inet_frag_queue - fragment queue

 *

 * @lock: spinlock protecting the queue

 * @timer: queue expiration timer

 * @list: hash bucket list

 * @refcnt: reference count of the queue

 * @fragments: received fragments head

 * @fragments_tail: received fragments tail

 * @stamp: timestamp of the last received fragment

 * @len: total length of the original datagram

 * @meat: length of received fragments so far

 * @flags: fragment queue flags

 * @max_size: (ipv4 only) maximum received fragment size with IP_DF set

 * @net: namespace that this frag belongs to

 */

struct inet_frag_queue {

	spinlock_t		lock;

	struct timer_list	timer;      /* when will this queue expire? */

	struct timer_list	timer;

	struct hlist_node	list;

	atomic_t		refcnt;

	struct sk_buff		*fragments; /* list of received fragments */

	struct sk_buff		*fragments;

	struct sk_buff		*fragments_tail;

	ktime_t			stamp;

	int			len;        /* total length of orig datagram */

	int			len;

	int			meat;

	__u8			flags;    /* first/last segment arrived? */

#define INET_FRAG_EVICTED	8

#define INET_FRAG_COMPLETE	4

#define INET_FRAG_FIRST_IN	2

#define INET_FRAG_LAST_IN	1

	__u8			flags;

	u16			max_size;

	struct netns_frags	*net;

};