include/net/pkt_sched.h

/* SPDX-License-Identifier: GPL-2.0 */
#ifndef __NET_PKT_SCHED_H
#define __NET_PKT_SCHED_H

#include <linux/jiffies.h>
#include <linux/ktime.h>
#include <linux/if_vlan.h>
#include <linux/netdevice.h>
#include <net/sch_generic.h>
#include <net/net_namespace.h>
#include <uapi/linux/pkt_sched.h>

#define DEFAULT_TX_QUEUE_LEN	1000
#define STAB_SIZE_LOG_MAX	30
#define QDISC_PKT_LEN_MAX	(1 << 20)	/* 1 MiB */

struct qdisc_walker {
	int	stop;
	int	skip;
	int	count;
	int	(*fn)(struct Qdisc *, unsigned long cl, struct qdisc_walker *);
};

#define qdisc_priv(q)							\
	_Generic(q,							\
		 const struct Qdisc * : (const void *)&q->privdata,	\
		 struct Qdisc * : (void *)&q->privdata)

/* 
   Timer resolution MUST BE < 10% of min_schedulable_packet_size/bandwidth
   
   Normal IP packet size ~ 512byte, hence:

   0.5Kbyte/1Mbyte/sec = 0.5msec, so that we need 50usec timer for
   10Mbit ethernet.

   10msec resolution -> <50Kbit/sec.
   
   The result: [34]86 is not good choice for QoS router :-(

   The things are not so bad, because we may use artificial
   clock evaluated by integration of network data flow
   in the most critical places.
 */

typedef u64	psched_time_t;

/* Avoid doing 64 bit divide */
#define PSCHED_SHIFT			6
#define PSCHED_TICKS2NS(x)		((s64)(x) << PSCHED_SHIFT)
#define PSCHED_NS2TICKS(x)		((x) >> PSCHED_SHIFT)

#define PSCHED_TICKS_PER_SEC		PSCHED_NS2TICKS(NSEC_PER_SEC)
#define PSCHED_PASTPERFECT		0

static inline psched_time_t psched_get_time(void)
{
	return PSCHED_NS2TICKS(ktime_get_ns());
}

struct qdisc_watchdog {
	struct hrtimer	timer;
	struct Qdisc	*qdisc;
};

void qdisc_watchdog_init_clockid(struct qdisc_watchdog *wd, struct Qdisc *qdisc,
				 clockid_t clockid);
void qdisc_watchdog_init(struct qdisc_watchdog *wd, struct Qdisc *qdisc);

void qdisc_watchdog_schedule_range_ns(struct qdisc_watchdog *wd, u64 expires,
				      u64 delta_ns);

static inline void qdisc_watchdog_schedule_ns(struct qdisc_watchdog *wd,
					      u64 expires)
{
	return qdisc_watchdog_schedule_range_ns(wd, expires, 0ULL);
}

static inline void qdisc_watchdog_schedule(struct qdisc_watchdog *wd,
					   psched_time_t expires)
{
	qdisc_watchdog_schedule_ns(wd, PSCHED_TICKS2NS(expires));
}

void qdisc_watchdog_cancel(struct qdisc_watchdog *wd);

extern struct Qdisc_ops pfifo_qdisc_ops;
extern struct Qdisc_ops bfifo_qdisc_ops;
extern struct Qdisc_ops pfifo_head_drop_qdisc_ops;

int fifo_set_limit(struct Qdisc *q, unsigned int limit);
struct Qdisc *fifo_create_dflt(struct Qdisc *sch, struct Qdisc_ops *ops,
			       unsigned int limit,
			       struct netlink_ext_ack *extack);

int register_qdisc(struct Qdisc_ops *qops);
void unregister_qdisc(struct Qdisc_ops *qops);
#define NET_SCH_ALIAS_PREFIX "net-sch-"
#define MODULE_ALIAS_NET_SCH(id)	MODULE_ALIAS(NET_SCH_ALIAS_PREFIX id)
void qdisc_get_default(char *id, size_t len);
int qdisc_set_default(const char *id);

void qdisc_hash_add(struct Qdisc *q, bool invisible);
void qdisc_hash_del(struct Qdisc *q);
struct Qdisc *qdisc_lookup(struct net_device *dev, u32 handle);
struct Qdisc *qdisc_lookup_rcu(struct net_device *dev, u32 handle);
struct qdisc_rate_table *qdisc_get_rtab(struct tc_ratespec *r,
					struct nlattr *tab,
					struct netlink_ext_ack *extack);
void qdisc_put_rtab(struct qdisc_rate_table *tab);
void qdisc_put_stab(struct qdisc_size_table *tab);
bool sch_direct_xmit(struct sk_buff *skb, struct Qdisc *q,
		     struct net_device *dev, struct netdev_queue *txq,
		     spinlock_t *root_lock, bool validate);

void __qdisc_run(struct Qdisc *q);

static inline struct sk_buff *qdisc_run(struct Qdisc *q)
{
	if (qdisc_run_begin(q)) {
		__qdisc_run(q);
		return qdisc_run_end(q);
	}
	return NULL;
}

extern const struct nla_policy rtm_tca_policy[TCA_MAX + 1];

/* Calculate maximal size of packet seen by hard_start_xmit
   routine of this device.
 */
static inline unsigned int psched_mtu(const struct net_device *dev)
{
	return READ_ONCE(dev->mtu) + dev->hard_header_len;
}

static inline struct net *qdisc_net(struct Qdisc *q)
{
	return dev_net(q->dev_queue->dev);
}

struct tc_query_caps_base {
	enum tc_setup_type type;
	void *caps;
};

struct tc_cbs_qopt_offload {
	u8 enable;
	s32 queue;
	s32 hicredit;
	s32 locredit;
	s32 idleslope;
	s32 sendslope;
};

struct tc_etf_qopt_offload {
	u8 enable;
	s32 queue;
};

struct tc_mqprio_caps {
	bool validate_queue_counts:1;
};

struct tc_mqprio_qopt_offload {
	/* struct tc_mqprio_qopt must always be the first element */
	struct tc_mqprio_qopt qopt;
	struct netlink_ext_ack *extack;
	u16 mode;
	u16 shaper;
	u32 flags;
	u64 min_rate[TC_QOPT_MAX_QUEUE];
	u64 max_rate[TC_QOPT_MAX_QUEUE];
	unsigned long preemptible_tcs;
};

struct tc_taprio_caps {
	bool supports_queue_max_sdu:1;
	bool gate_mask_per_txq:1;
	/* Device expects lower TXQ numbers to have higher priority over higher
	 * TXQs, regardless of their TC mapping. DO NOT USE FOR NEW DRIVERS,
	 * INSTEAD ENFORCE A PROPER TC:TXQ MAPPING COMING FROM USER SPACE.
	 */
	bool broken_mqprio:1;
};

enum tc_taprio_qopt_cmd {
	TAPRIO_CMD_REPLACE,
	TAPRIO_CMD_DESTROY,
	TAPRIO_CMD_STATS,
	TAPRIO_CMD_QUEUE_STATS,
};

/**
 * struct tc_taprio_qopt_stats - IEEE 802.1Qbv statistics
 * @window_drops: Frames that were dropped because they were too large to be
 *	transmitted in any of the allotted time windows (open gates) for their
 *	traffic class.
 * @tx_overruns: Frames still being transmitted by the MAC after the
 *	transmission gate associated with their traffic class has closed.
 *	Equivalent to `12.29.1.1.2 TransmissionOverrun` from 802.1Q-2018.
 */
struct tc_taprio_qopt_stats {
	u64 window_drops;
	u64 tx_overruns;
};

struct tc_taprio_qopt_queue_stats {
	int queue;
	struct tc_taprio_qopt_stats stats;
};

struct tc_taprio_sched_entry {
	u8 command; /* TC_TAPRIO_CMD_* */

	/* The gate_mask in the offloading side refers to traffic classes */
	u32 gate_mask;
	u32 interval;
};

struct tc_taprio_qopt_offload {
	enum tc_taprio_qopt_cmd cmd;

	union {
		/* TAPRIO_CMD_STATS */
		struct tc_taprio_qopt_stats stats;
		/* TAPRIO_CMD_QUEUE_STATS */
		struct tc_taprio_qopt_queue_stats queue_stats;
		/* TAPRIO_CMD_REPLACE */
		struct {
			struct tc_mqprio_qopt_offload mqprio;
			struct netlink_ext_ack *extack;
			ktime_t base_time;
			u64 cycle_time;
			u64 cycle_time_extension;
			u32 max_sdu[TC_MAX_QUEUE];

			size_t num_entries;
			struct tc_taprio_sched_entry entries[];
		};
	};
};

#if IS_ENABLED(CONFIG_NET_SCH_TAPRIO)

/* Reference counting */
struct tc_taprio_qopt_offload *taprio_offload_get(struct tc_taprio_qopt_offload
						  *offload);
void taprio_offload_free(struct tc_taprio_qopt_offload *offload);

#else

/* Reference counting */
static inline struct tc_taprio_qopt_offload *
taprio_offload_get(struct tc_taprio_qopt_offload *offload)
{
	return NULL;
}

static inline void taprio_offload_free(struct tc_taprio_qopt_offload *offload)
{
}

#endif

/* Ensure skb_mstamp_ns, which might have been populated with the txtime, is
 * not mistaken for a software timestamp, because this will otherwise prevent
 * the dispatch of hardware timestamps to the socket.
 */
static inline void skb_txtime_consumed(struct sk_buff *skb)
{
	skb->tstamp = ktime_set(0, 0);
}

static inline bool tc_qdisc_stats_dump(struct Qdisc *sch,
				       unsigned long cl,
				       struct qdisc_walker *arg)
{
	if (arg->count >= arg->skip && arg->fn(sch, cl, arg) < 0) {
		arg->stop = 1;
		return false;
	}

	arg->count++;
	return true;
}

static inline void qdisc_warn_nonwc(const char *txt, struct Qdisc *qdisc)
{
	if (!(qdisc->flags & TCQ_F_WARN_NONWC)) {
		pr_warn("%s: %s qdisc %X: is non-work-conserving?\n",
			txt, qdisc->ops->id, qdisc->handle >> 16);
		qdisc->flags |= TCQ_F_WARN_NONWC;
	}
}

static inline unsigned int qdisc_peek_len(struct Qdisc *sch)
{
	struct sk_buff *skb;
	unsigned int len;

	skb = sch->ops->peek(sch);
	if (unlikely(skb == NULL)) {
		qdisc_warn_nonwc("qdisc_peek_len", sch);
		return 0;
	}
	len = qdisc_pkt_len(skb);

	return len;
}

static inline void qdisc_lock_init(struct Qdisc *sch,
				   const struct Qdisc_ops *ops)
{
	spin_lock_init(&sch->q.lock);

	/* Skip dynamic keys if nesting is not possible */
	if (ops->static_flags & TCQ_F_INGRESS ||
	    ops == &noqueue_qdisc_ops)
		return;

	lockdep_register_key(&sch->root_lock_key);
	lockdep_set_class(&sch->q.lock, &sch->root_lock_key);
}

static inline void qdisc_lock_uninit(struct Qdisc *sch,
				     const struct Qdisc_ops *ops)
{
	if (ops->static_flags & TCQ_F_INGRESS ||
	    ops == &noqueue_qdisc_ops)
		return;

	lockdep_unregister_key(&sch->root_lock_key);
}

#endif