1/* SPDX-License-Identifier: GPL-2.0-only */
  2/*
  3 * Copyright (c) 2016 Qualcomm Atheros, Inc
  4 *
  5 * Based on net/sched/sch_fq_codel.c
  6 */
  7#ifndef __NET_SCHED_FQ_H
  8#define __NET_SCHED_FQ_H
  9
 10struct fq_tin;
 11
 12/**
 13 * struct fq_flow - per traffic flow queue
 14 *
 15 * @tin: owner of this flow. Used to manage collisions, i.e. when a packet
 16 *	hashes to an index which points to a flow that is already owned by a
 17 *	different tin the packet is destined to. In such case the implementer
 18 *	must provide a fallback flow
 19 * @flowchain: can be linked to fq_tin's new_flows or old_flows. Used for DRR++
 20 *	(deficit round robin) based round robin queuing similar to the one
 21 *	found in net/sched/sch_fq_codel.c
 22 * @backlogchain: can be linked to other fq_flow and fq. Used to keep track of
 23 *	fat flows and efficient head-dropping if packet limit is reached
 24 * @queue: sk_buff queue to hold packets
 25 * @backlog: number of bytes pending in the queue. The number of packets can be
 26 *	found in @queue.qlen
 27 * @deficit: used for DRR++
 28 */
 29struct fq_flow {
 30	struct fq_tin *tin;
 31	struct list_head flowchain;
 32	struct list_head backlogchain;
 33	struct sk_buff_head queue;
 34	u32 backlog;
 35	int deficit;
 36};
 37
 38/**
 39 * struct fq_tin - a logical container of fq_flows
 40 *
 41 * Used to group fq_flows into a logical aggregate. DRR++ scheme is used to
 42 * pull interleaved packets out of the associated flows.
 43 *
 44 * @new_flows: linked list of fq_flow
 45 * @old_flows: linked list of fq_flow
 46 */
 47struct fq_tin {
 48	struct list_head new_flows;
 49	struct list_head old_flows;
 50	u32 backlog_bytes;
 51	u32 backlog_packets;
 52	u32 overlimit;
 53	u32 collisions;
 54	u32 flows;
 55	u32 tx_bytes;
 56	u32 tx_packets;
 57};
 58
 59/**
 60 * struct fq - main container for fair queuing purposes
 61 *
 62 * @backlogs: linked to fq_flows. Used to maintain fat flows for efficient
 63 *	head-dropping when @backlog reaches @limit
 64 * @limit: max number of packets that can be queued across all flows
 65 * @backlog: number of packets queued across all flows
 66 */
 67struct fq {
 68	struct fq_flow *flows;
 69	struct list_head backlogs;
 70	spinlock_t lock;
 71	u32 flows_cnt;
 72	siphash_key_t	perturbation;
 73	u32 limit;
 74	u32 memory_limit;
 75	u32 memory_usage;
 76	u32 quantum;
 77	u32 backlog;
 78	u32 overlimit;
 79	u32 overmemory;
 80	u32 collisions;
 81};
 82
 83typedef struct sk_buff *fq_tin_dequeue_t(struct fq *,
 84					 struct fq_tin *,
 85					 struct fq_flow *flow);
 86
 87typedef void fq_skb_free_t(struct fq *,
 88			   struct fq_tin *,
 89			   struct fq_flow *,
 90			   struct sk_buff *);
 91
 92/* Return %true to filter (drop) the frame. */
 93typedef bool fq_skb_filter_t(struct fq *,
 94			     struct fq_tin *,
 95			     struct fq_flow *,
 96			     struct sk_buff *,
 97			     void *);
 98
 99typedef struct fq_flow *fq_flow_get_default_t(struct fq *,
100					      struct fq_tin *,
101					      int idx,
102					      struct sk_buff *);
103
104#endif