/* SPDX-License-Identifier: GPL-2.0 */

  #ifndef __NET_FRAG_H__
  #define __NET_FRAG_H__

  #include <linux/rhashtable.h>

  struct netns_frags {

  	/* sysctls */

  	long			high_thresh;
  	long			low_thresh;

  	int			timeout;

  	int			max_dist;

  	struct inet_frags	*f;

  
  	struct rhashtable       rhashtable ____cacheline_aligned_in_smp;
  
  	/* Keep atomic mem on separate cachelines in structs that include it */
  	atomic_long_t		mem ____cacheline_aligned_in_smp;

  };

  /**
   * 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

   */
  enum {
  	INET_FRAG_FIRST_IN	= BIT(0),
  	INET_FRAG_LAST_IN	= BIT(1),
  	INET_FRAG_COMPLETE	= BIT(2),

  };

  struct frag_v4_compare_key {
  	__be32		saddr;
  	__be32		daddr;
  	u32		user;
  	u32		vif;
  	__be16		id;
  	u16		protocol;
  };
  
  struct frag_v6_compare_key {
  	struct in6_addr	saddr;
  	struct in6_addr	daddr;
  	u32		user;
  	__be32		id;
  	u32		iif;
  };

  /**
   * struct inet_frag_queue - fragment queue
   *

   * @node: rhash node
   * @key: keys identifying this frag.

   * @timer: queue expiration timer

   * @lock: spinlock protecting this frag

   * @refcnt: reference count of the queue
   * @fragments: received fragments head

   * @rb_fragments: received fragments rb-tree root

   * @fragments_tail: received fragments tail

   * @last_run_head: the head of the last "run". see ip_fragment.c

   * @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: maximum received fragment size

   * @net: namespace that this frag belongs to

   * @rcu: rcu head for freeing deferall

   */

  struct inet_frag_queue {

  	struct rhash_head	node;
  	union {
  		struct frag_v4_compare_key v4;
  		struct frag_v6_compare_key v6;
  	} key;

  	struct timer_list	timer;

  	spinlock_t		lock;

  	refcount_t		refcnt;

  	struct sk_buff		*fragments;  /* Used in IPv6. */
  	struct rb_root		rb_fragments; /* Used in IPv4. */

  	struct sk_buff		*fragments_tail;

  	struct sk_buff		*last_run_head;

  	ktime_t			stamp;

  	int			len;

  	int			meat;

  	__u8			flags;

  	u16			max_size;

  	struct netns_frags      *net;
  	struct rcu_head		rcu;

  };

  struct inet_frags {

  	unsigned int		qsize;

  	void			(*constructor)(struct inet_frag_queue *q,

  					       const void *arg);

  	void			(*destructor)(struct inet_frag_queue *);

  	void			(*frag_expire)(struct timer_list *t);

  	struct kmem_cache	*frags_cachep;
  	const char		*frags_cache_name;

  	struct rhashtable_params rhash_params;

  };

  int inet_frags_init(struct inet_frags *);

  void inet_frags_fini(struct inet_frags *);

  static inline int inet_frags_init_net(struct netns_frags *nf)

  {

  	atomic_long_set(&nf->mem, 0);

  	return rhashtable_init(&nf->rhashtable, &nf->f->rhash_params);

  }

  void inet_frags_exit_net(struct netns_frags *nf);

  void inet_frag_kill(struct inet_frag_queue *q);
  void inet_frag_destroy(struct inet_frag_queue *q);

  struct inet_frag_queue *inet_frag_find(struct netns_frags *nf, void *key);

  /* Free all skbs in the queue; return the sum of their truesizes. */
  unsigned int inet_frag_rbtree_purge(struct rb_root *root);

  static inline void inet_frag_put(struct inet_frag_queue *q)

  {

  	if (refcount_dec_and_test(&q->refcnt))

  		inet_frag_destroy(q);

  }

  /* Memory Tracking Functions. */

  static inline long frag_mem_limit(const struct netns_frags *nf)

  {

  	return atomic_long_read(&nf->mem);

  }

  static inline void sub_frag_mem_limit(struct netns_frags *nf, long val)

  {

  	atomic_long_sub(val, &nf->mem);

  }

  static inline void add_frag_mem_limit(struct netns_frags *nf, long val)

  {

  	atomic_long_add(val, &nf->mem);

  }

  /* RFC 3168 support :
   * We want to check ECN values of all fragments, do detect invalid combinations.
   * In ipq->ecn, we store the OR value of each ip4_frag_ecn() fragment value.
   */
  #define	IPFRAG_ECN_NOT_ECT	0x01 /* one frag had ECN_NOT_ECT */
  #define	IPFRAG_ECN_ECT_1	0x02 /* one frag had ECN_ECT_1 */
  #define	IPFRAG_ECN_ECT_0	0x04 /* one frag had ECN_ECT_0 */
  #define	IPFRAG_ECN_CE		0x08 /* one frag had ECN_CE */
  
  extern const u8 ip_frag_ecn_table[16];

  #endif