/*
   * Copyright (c) 2016 Qualcomm Atheros, Inc
   *
   * GPL v2
   *
   * Based on net/sched/sch_fq_codel.c
   */
  #ifndef __NET_SCHED_FQ_H
  #define __NET_SCHED_FQ_H
  
  struct fq_tin;
  
  /**
   * struct fq_flow - per traffic flow queue
   *
   * @tin: owner of this flow. Used to manage collisions, i.e. when a packet
   *	hashes to an index which points to a flow that is already owned by a
   *	different tin the packet is destined to. In such case the implementer
   *	must provide a fallback flow
   * @flowchain: can be linked to fq_tin's new_flows or old_flows. Used for DRR++
   *	(deficit round robin) based round robin queuing similar to the one
   *	found in net/sched/sch_fq_codel.c
   * @backlogchain: can be linked to other fq_flow and fq. Used to keep track of
   *	fat flows and efficient head-dropping if packet limit is reached
   * @queue: sk_buff queue to hold packets
   * @backlog: number of bytes pending in the queue. The number of packets can be
   *	found in @queue.qlen
   * @deficit: used for DRR++
   */
  struct fq_flow {
  	struct fq_tin *tin;
  	struct list_head flowchain;
  	struct list_head backlogchain;
  	struct sk_buff_head queue;
  	u32 backlog;
  	int deficit;
  };
  
  /**
   * struct fq_tin - a logical container of fq_flows
   *
   * Used to group fq_flows into a logical aggregate. DRR++ scheme is used to
   * pull interleaved packets out of the associated flows.
   *
   * @new_flows: linked list of fq_flow
   * @old_flows: linked list of fq_flow
   */
  struct fq_tin {
  	struct list_head new_flows;
  	struct list_head old_flows;
  	u32 backlog_bytes;
  	u32 backlog_packets;
  	u32 overlimit;
  	u32 collisions;
  	u32 flows;
  	u32 tx_bytes;
  	u32 tx_packets;
  };
  
  /**
   * struct fq - main container for fair queuing purposes
   *
   * @backlogs: linked to fq_flows. Used to maintain fat flows for efficient
   *	head-dropping when @backlog reaches @limit
   * @limit: max number of packets that can be queued across all flows
   * @backlog: number of packets queued across all flows
   */
  struct fq {
  	struct fq_flow *flows;
  	struct list_head backlogs;
  	spinlock_t lock;
  	u32 flows_cnt;
  	u32 perturbation;
  	u32 limit;

  	u32 memory_limit;
  	u32 memory_usage;

  	u32 quantum;
  	u32 backlog;
  	u32 overlimit;

  	u32 overmemory;

  	u32 collisions;
  };
  
  typedef struct sk_buff *fq_tin_dequeue_t(struct fq *,
  					 struct fq_tin *,
  					 struct fq_flow *flow);
  
  typedef void fq_skb_free_t(struct fq *,
  			   struct fq_tin *,
  			   struct fq_flow *,
  			   struct sk_buff *);
  
  typedef struct fq_flow *fq_flow_get_default_t(struct fq *,
  					      struct fq_tin *,
  					      int idx,
  					      struct sk_buff *);
  
  #endif