--- /dev/null
+// 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/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)
+
+struct etf_sched_data {
+ 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 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.
+ */
+ 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(&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)
+ return;
+
+ next = ktime_sub_ns(skb->tstamp, q->delta);
+ qdisc_watchdog_schedule_ns(&q->watchdog, ktime_to_ns(next));
+}
+
+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_node, *parent = NULL;
+ ktime_t txtime = nskb->tstamp;
+
+ if (!is_packet_valid(sch, nskb))
+ 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;
+ else
+ p = &parent->rb_left;
+ }
+ rb_link_node(&nskb->rbnode, parent, p);
+ rb_insert_color(&nskb->rbnode, &q->head);
+
+ 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(&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;
+
+ 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. */
+ /* FIXME: Must return error on the socket's error 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);
+
+ /* Dequeue only if now is within the [txtime - delta, txtime] range. */
+ if (ktime_after(now, next))
+ timesortedlist_erase(sch, skb, false);
+ else
+ skb = NULL;
+
+out:
+ /* Now we may need to re-arm the qdisc watchdog for the next packet. */
+ reset_watchdog(sch);
+
+ return skb;
+}
+
+static int etf_init(struct Qdisc *sch, struct nlattr *opt,
+ struct netlink_ext_ack *extack)
+{
+ struct etf_sched_data *q = qdisc_priv(sch);
+ struct net_device *dev = qdisc_dev(sch);
+ struct nlattr *tb[TCA_ETF_MAX + 1];
+ struct tc_etf_qopt *qopt;
+ int err;
+
+ if (!opt) {
+ NL_SET_ERR_MSG(extack,
+ "Missing ETF qdisc options which are mandatory");
+ return -EINVAL;
+ }
+
+ err = nla_parse_nested(tb, TCA_ETF_MAX, opt, etf_policy, extack);
+ if (err < 0)
+ return err;
+
+ if (!tb[TCA_ETF_PARMS]) {
+ NL_SET_ERR_MSG(extack, "Missing mandatory ETF parameters");
+ return -EINVAL;
+ }
+
+ qopt = nla_data(tb[TCA_ETF_PARMS]);
+
+ pr_debug("delta %d clockid %d deadline %s\n",
+ qopt->delta, qopt->clockid,
+ DEADLINE_MODE_IS_ON(qopt) ? "on" : "off");
+
+ err = validate_input_params(qopt, extack);
+ if (err < 0)
+ return err;
+
+ q->queue = sch->dev_queue - netdev_get_tx_queue(dev, 0);
+
+ /* Everything went OK, save the parameters used. */
+ q->delta = qopt->delta;
+ q->clockid = qopt->clockid;
+ q->deadline_mode = DEADLINE_MODE_IS_ON(qopt);
+
+ switch (q->clockid) {
+ case CLOCK_REALTIME:
+ q->get_time = ktime_get_real;
+ break;
+ case CLOCK_MONOTONIC:
+ q->get_time = ktime_get;
+ break;
+ case CLOCK_BOOTTIME:
+ q->get_time = ktime_get_boottime;
+ break;
+ case CLOCK_TAI:
+ q->get_time = ktime_get_clocktai;
+ break;
+ default:
+ NL_SET_ERR_MSG(extack, "Clockid is not supported");
+ return -ENOTSUPP;
+ }
+
+ qdisc_watchdog_init_clockid(&q->watchdog, sch, q->clockid);
+
+ return 0;
+}
+
+static void timesortedlist_clear(struct Qdisc *sch)
+{
+ struct etf_sched_data *q = qdisc_priv(sch);
+ struct rb_node *p = rb_first(&q->head);
+
+ while (p) {
+ struct sk_buff *skb = rb_to_skb(p);
+
+ p = rb_next(p);
+
+ rb_erase(&skb->rbnode, &q->head);
+ rtnl_kfree_skbs(skb, skb);
+ sch->q.qlen--;
+ }
+}
+
+static void etf_reset(struct Qdisc *sch)
+{
+ struct etf_sched_data *q = qdisc_priv(sch);
+
+ /* Only cancel watchdog if it's been initialized. */
+ if (q->watchdog.qdisc == sch)
+ qdisc_watchdog_cancel(&q->watchdog);
+
+ /* No matter which mode we are on, it's safe to clear both lists. */
+ timesortedlist_clear(sch);
+ __qdisc_reset_queue(&sch->q);
+
+ sch->qstats.backlog = 0;
+ sch->q.qlen = 0;
+
+ q->last = 0;
+}
+
+static void etf_destroy(struct Qdisc *sch)
+{
+ struct etf_sched_data *q = qdisc_priv(sch);
+
+ /* Only cancel watchdog if it's been initialized. */
+ if (q->watchdog.qdisc == sch)
+ qdisc_watchdog_cancel(&q->watchdog);
+}
+
+static int etf_dump(struct Qdisc *sch, struct sk_buff *skb)
+{
+ struct etf_sched_data *q = qdisc_priv(sch);
+ struct tc_etf_qopt opt = { };
+ struct nlattr *nest;
+
+ nest = nla_nest_start(skb, TCA_OPTIONS);
+ if (!nest)
+ goto nla_put_failure;
+
+ opt.delta = q->delta;
+ opt.clockid = q->clockid;
+ if (q->deadline_mode)
+ opt.flags |= TC_ETF_DEADLINE_MODE_ON;
+
+ if (nla_put(skb, TCA_ETF_PARMS, sizeof(opt), &opt))
+ goto nla_put_failure;
+
+ return nla_nest_end(skb, nest);
+
+nla_put_failure:
+ nla_nest_cancel(skb, nest);
+ return -1;
+}
+
+static struct Qdisc_ops etf_qdisc_ops __read_mostly = {
+ .id = "etf",
+ .priv_size = sizeof(struct etf_sched_data),
+ .enqueue = etf_enqueue_timesortedlist,
+ .dequeue = etf_dequeue_timesortedlist,
+ .peek = etf_peek_timesortedlist,
+ .init = etf_init,
+ .reset = etf_reset,
+ .destroy = etf_destroy,
+ .dump = etf_dump,
+ .owner = THIS_MODULE,
+};
+
+static int __init etf_module_init(void)
+{
+ return register_qdisc(&etf_qdisc_ops);
+}
+
+static void __exit etf_module_exit(void)
+{
+ unregister_qdisc(&etf_qdisc_ops);
+}
+module_init(etf_module_init)
+module_exit(etf_module_exit)
+MODULE_LICENSE("GPL");
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