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// SPDX-License-Identifier: GPL-2.0
/* net/sched/sch_etf.c Earliest TxTime First queueing discipline.
*
* Authors: Jesus Sanchez-Palencia <jesus.sanchez-palencia@intel.com>
* Vinicius Costa Gomes <vinicius.gomes@intel.com>
*/
#include <linux/module.h>
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/string.h>
#include <linux/errno.h>
#include <linux/errqueue.h>
#include <linux/rbtree.h>
#include <linux/skbuff.h>
#include <linux/posix-timers.h>
#include <net/netlink.h>
#include <net/sch_generic.h>
#include <net/pkt_sched.h>
#include <net/sock.h>
#define DEADLINE_MODE_IS_ON(x) ((x)->flags & TC_ETF_DEADLINE_MODE_ON)
#define OFFLOAD_IS_ON(x) ((x)->flags & TC_ETF_OFFLOAD_ON)
struct etf_sched_data {
bool offload;
bool deadline_mode;
int clockid;
int queue;
s32 delta; /* in ns */
ktime_t last; /* The txtime of the last skb sent to the netdevice. */
struct rb_root_cached head;
struct qdisc_watchdog watchdog;
ktime_t (*get_time)(void);
};
static const struct nla_policy etf_policy[TCA_ETF_MAX + 1] = {
[TCA_ETF_PARMS] = { .len = sizeof(struct tc_etf_qopt) },
};
static inline int validate_input_params(struct tc_etf_qopt *qopt,
struct netlink_ext_ack *extack)
{
/* Check if params comply to the following rules:
* * Clockid and delta must be valid.
*
* * Dynamic clockids are not supported.
*
* * Delta must be a positive integer.
*
* Also note that for the HW offload case, we must
* expect that system clocks have been synchronized to PHC.
*/
if (qopt->clockid < 0) {
NL_SET_ERR_MSG(extack, "Dynamic clockids are not supported");
return -ENOTSUPP;
}
if (qopt->clockid != CLOCK_TAI) {
NL_SET_ERR_MSG(extack, "Invalid clockid. CLOCK_TAI must be used");
return -EINVAL;
}
if (qopt->delta < 0) {
NL_SET_ERR_MSG(extack, "Delta must be positive");
return -EINVAL;
}
return 0;
}
static bool is_packet_valid(struct Qdisc *sch, struct sk_buff *nskb)
{
struct etf_sched_data *q = qdisc_priv(sch);
ktime_t txtime = nskb->tstamp;
struct sock *sk = nskb->sk;
ktime_t now;
if (!sk)
return false;
if (!sock_flag(sk, SOCK_TXTIME))
return false;
/* We don't perform crosstimestamping.
* Drop if packet's clockid differs from qdisc's.
*/
if (sk->sk_clockid != q->clockid)
return false;
if (sk->sk_txtime_deadline_mode != q->deadline_mode)
return false;
now = q->get_time();
if (ktime_before(txtime, now) || ktime_before(txtime, q->last))
return false;
return true;
}
static struct sk_buff *etf_peek_timesortedlist(struct Qdisc *sch)
{
struct etf_sched_data *q = qdisc_priv(sch);
struct rb_node *p;
p = rb_first_cached(&q->head);
if (!p)
return NULL;
return rb_to_skb(p);
}
static void reset_watchdog(struct Qdisc *sch)
{
struct etf_sched_data *q = qdisc_priv(sch);
struct sk_buff *skb = etf_peek_timesortedlist(sch);
ktime_t next;
if (!skb) {
qdisc_watchdog_cancel(&q->watchdog);
return;
}
next = ktime_sub_ns(skb->tstamp, q->delta);
qdisc_watchdog_schedule_ns(&q->watchdog, ktime_to_ns(next));
}
static void report_sock_error(struct sk_buff *skb, u32 err, u8 code)
{
struct sock_exterr_skb *serr;
struct sk_buff *clone;
ktime_t txtime = skb->tstamp;
if (!skb->sk || !(skb->sk->sk_txtime_report_errors))
return;
clone = skb_clone(skb, GFP_ATOMIC);
if (!clone)
return;
serr = SKB_EXT_ERR(clone);
serr->ee.ee_errno = err;
serr->ee.ee_origin = SO_EE_ORIGIN_TXTIME;
serr->ee.ee_type = 0;
serr->ee.ee_code = code;
serr->ee.ee_pad = 0;
serr->ee.ee_data = (txtime >> 32); /* high part of tstamp */
serr->ee.ee_info = txtime; /* low part of tstamp */
if (sock_queue_err_skb(skb->sk, clone))
kfree_skb(clone);
}
static int etf_enqueue_timesortedlist(struct sk_buff *nskb, struct Qdisc *sch,
struct sk_buff **to_free)
{
struct etf_sched_data *q = qdisc_priv(sch);
struct rb_node **p = &q->head.rb_root.rb_node, *parent = NULL;
ktime_t txtime = nskb->tstamp;
bool leftmost = true;
if (!is_packet_valid(sch, nskb)) {
report_sock_error(nskb, EINVAL,
SO_EE_CODE_TXTIME_INVALID_PARAM);
return qdisc_drop(nskb, sch, to_free);
}
while (*p) {
struct sk_buff *skb;
parent = *p;
skb = rb_to_skb(parent);
if (ktime_after(txtime, skb->tstamp)) {
p = &parent->rb_right;
leftmost = false;
} else {
p = &parent->rb_left;
}
}
rb_link_node(&nskb->rbnode, parent, p);
rb_insert_color_cached(&nskb->rbnode, &q->head, leftmost);
qdisc_qstats_backlog_inc(sch, nskb);
sch->q.qlen++;
/* Now we may need to re-arm the qdisc watchdog for the next packet. */
reset_watchdog(sch);
return NET_XMIT_SUCCESS;
}
static void timesortedlist_erase(struct Qdisc *sch, struct sk_buff *skb,
bool drop)
{
struct etf_sched_data *q = qdisc_priv(sch);
rb_erase_cached(&skb->rbnode, &q->head);
/* The rbnode field in the skb re-uses these fields, now that
* we are done with the rbnode, reset them.
*/
skb->next = NULL;
skb->prev = NULL;
skb->dev = qdisc_dev(sch);
qdisc_qstats_backlog_dec(sch, skb);
if (drop) {
struct sk_buff *to_free = NULL;
report_sock_error(skb, ECANCELED, SO_EE_CODE_TXTIME_MISSED);
qdisc_drop(skb, sch, &to_free);
kfree_skb_list(to_free);
qdisc_qstats_overlimit(sch);
} else {
qdisc_bstats_update(sch, skb);
q->last = skb->tstamp;
}
sch->q.qlen--;
}
static struct sk_buff *etf_dequeue_timesortedlist(struct Qdisc *sch)
{
struct etf_sched_data *q = qdisc_priv(sch);
struct sk_buff *skb;
ktime_t now, next;
skb = etf_peek_timesortedlist(sch);
if (!skb)
return NULL;
now = q->get_time();
/* Drop if packet has expired while in queue. */
if (ktime_before(skb->tstamp, now)) {
timesortedlist_erase(sch, skb, true);
skb = NULL;
goto out;
}
/* When in deadline mode, dequeue as soon as possible and change the
* txtime from deadline to (now + delta).
*/
if (q->deadline_mode) {
timesortedlist_erase(sch, skb, false);
skb->tstamp = now;
goto out;
}
next = ktime_sub_ns(skb->tstamp, q->delta<
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