--- /dev/null
+/*
+ * Codel - The Controlled-Delay Active Queue Management algorithm
+ *
+ * Copyright (C) 2011-2012 Kathleen Nichols <nichols@pollere.com>
+ * Copyright (C) 2011-2012 Van Jacobson <van@pollere.net>
+ *
+ * Implemented on linux by :
+ * Copyright (C) 2012 Michael D. Taht <dave.taht@bufferbloat.net>
+ * Copyright (C) 2012 Eric Dumazet <edumazet@google.com>
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ * notice, this list of conditions, and the following disclaimer,
+ * without modification.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ * 3. The names of the authors may not be used to endorse or promote products
+ * derived from this software without specific prior written permission.
+ *
+ * Alternatively, provided that this notice is retained in full, this
+ * software may be distributed under the terms of the GNU General
+ * Public License ("GPL") version 2, in which case the provisions of the
+ * GPL apply INSTEAD OF those given above.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH
+ * DAMAGE.
+ *
+ */
+
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/types.h>
+#include <linux/kernel.h>
+#include <linux/errno.h>
+#include <linux/skbuff.h>
+#include <linux/prefetch.h>
+#include <net/pkt_sched.h>
+#include <net/codel.h>
+
+
+#define DEFAULT_CODEL_LIMIT 1000
+
+struct codel_sched_data {
+ struct codel_params params;
+ struct codel_vars vars;
+ struct codel_stats stats;
+ u32 drop_overlimit;
+};
+
+/* This is the specific function called from codel_dequeue()
+ * to dequeue a packet from queue. Note: backlog is handled in
+ * codel, we dont need to reduce it here.
+ */
+static struct sk_buff *dequeue(struct codel_vars *vars, struct Qdisc *sch)
+{
+ struct sk_buff *skb = __skb_dequeue(&sch->q);
+
+ prefetch(&skb->end); /* we'll need skb_shinfo() */
+ return skb;
+}
+
+static struct sk_buff *codel_qdisc_dequeue(struct Qdisc *sch)
+{
+ struct codel_sched_data *q = qdisc_priv(sch);
+ struct sk_buff *skb;
+
+ skb = codel_dequeue(sch, &q->params, &q->vars, &q->stats, dequeue);
+
+ /* We cant call qdisc_tree_decrease_qlen() if our qlen is 0,
+ * or HTB crashes. Defer it for next round.
+ */
+ if (q->stats.drop_count && sch->q.qlen) {
+ qdisc_tree_decrease_qlen(sch, q->stats.drop_count);
+ q->stats.drop_count = 0;
+ }
+ if (skb)
+ qdisc_bstats_update(sch, skb);
+ return skb;
+}
+
+static int codel_qdisc_enqueue(struct sk_buff *skb, struct Qdisc *sch)
+{
+ struct codel_sched_data *q;
+
+ if (likely(qdisc_qlen(sch) < sch->limit)) {
+ codel_set_enqueue_time(skb);
+ return qdisc_enqueue_tail(skb, sch);
+ }
+ q = qdisc_priv(sch);
+ q->drop_overlimit++;
+ return qdisc_drop(skb, sch);
+}
+
+static const struct nla_policy codel_policy[TCA_CODEL_MAX + 1] = {
+ [TCA_CODEL_TARGET] = { .type = NLA_U32 },
+ [TCA_CODEL_LIMIT] = { .type = NLA_U32 },
+ [TCA_CODEL_INTERVAL] = { .type = NLA_U32 },
+ [TCA_CODEL_ECN] = { .type = NLA_U32 },
+};
+
+static int codel_change(struct Qdisc *sch, struct nlattr *opt)
+{
+ struct codel_sched_data *q = qdisc_priv(sch);
+ struct nlattr *tb[TCA_CODEL_MAX + 1];
+ unsigned int qlen;
+ int err;
+
+ if (!opt)
+ return -EINVAL;
+
+ err = nla_parse_nested(tb, TCA_CODEL_MAX, opt, codel_policy);
+ if (err < 0)
+ return err;
+
+ sch_tree_lock(sch);
+
+ if (tb[TCA_CODEL_TARGET]) {
+ u32 target = nla_get_u32(tb[TCA_CODEL_TARGET]);
+
+ q->params.target = ((u64)target * NSEC_PER_USEC) >> CODEL_SHIFT;
+ }
+
+ if (tb[TCA_CODEL_INTERVAL]) {
+ u32 interval = nla_get_u32(tb[TCA_CODEL_INTERVAL]);
+
+ q->params.interval = ((u64)interval * NSEC_PER_USEC) >> CODEL_SHIFT;
+ }
+
+ if (tb[TCA_CODEL_LIMIT])
+ sch->limit = nla_get_u32(tb[TCA_CODEL_LIMIT]);
+
+ if (tb[TCA_CODEL_ECN])
+ q->params.ecn = !!nla_get_u32(tb[TCA_CODEL_ECN]);
+
+ qlen = sch->q.qlen;
+ while (sch->q.qlen > sch->limit) {
+ struct sk_buff *skb = __skb_dequeue(&sch->q);
+
+ qdisc_qstats_backlog_dec(sch, skb);
+ qdisc_drop(skb, sch);
+ }
+ qdisc_tree_decrease_qlen(sch, qlen - sch->q.qlen);
+
+ sch_tree_unlock(sch);
+ return 0;
+}
+
+static int codel_init(struct Qdisc *sch, struct nlattr *opt)
+{
+ struct codel_sched_data *q = qdisc_priv(sch);
+
+ sch->limit = DEFAULT_CODEL_LIMIT;
+
+ codel_params_init(&q->params, sch);
+ codel_vars_init(&q->vars);
+ codel_stats_init(&q->stats);
+
+ if (opt) {
+ int err = codel_change(sch, opt);
+
+ if (err)
+ return err;
+ }
+
+ if (sch->limit >= 1)
+ sch->flags |= TCQ_F_CAN_BYPASS;
+ else
+ sch->flags &= ~TCQ_F_CAN_BYPASS;
+
+ return 0;
+}
+
+static int codel_dump(struct Qdisc *sch, struct sk_buff *skb)
+{
+ struct codel_sched_data *q = qdisc_priv(sch);
+ struct nlattr *opts;
+
+ opts = nla_nest_start(skb, TCA_OPTIONS);
+ if (opts == NULL)
+ goto nla_put_failure;
+
+ if (nla_put_u32(skb, TCA_CODEL_TARGET,
+ codel_time_to_us(q->params.target)) ||
+ nla_put_u32(skb, TCA_CODEL_LIMIT,
+ sch->limit) ||
+ nla_put_u32(skb, TCA_CODEL_INTERVAL,
+ codel_time_to_us(q->params.interval)) ||
+ nla_put_u32(skb, TCA_CODEL_ECN,
+ q->params.ecn))
+ goto nla_put_failure;
+
+ return nla_nest_end(skb, opts);
+
+nla_put_failure:
+ nla_nest_cancel(skb, opts);
+ return -1;
+}
+
+static int codel_dump_stats(struct Qdisc *sch, struct gnet_dump *d)
+{
+ const struct codel_sched_data *q = qdisc_priv(sch);
+ struct tc_codel_xstats st = {
+ .maxpacket = q->stats.maxpacket,
+ .count = q->vars.count,
+ .lastcount = q->vars.lastcount,
+ .drop_overlimit = q->drop_overlimit,
+ .ldelay = codel_time_to_us(q->vars.ldelay),
+ .dropping = q->vars.dropping,
+ .ecn_mark = q->stats.ecn_mark,
+ };
+
+ if (q->vars.dropping) {
+ codel_tdiff_t delta = q->vars.drop_next - codel_get_time();
+
+ if (delta >= 0)
+ st.drop_next = codel_time_to_us(delta);
+ else
+ st.drop_next = -codel_time_to_us(-delta);
+ }
+
+ return gnet_stats_copy_app(d, &st, sizeof(st));
+}
+
+static void codel_reset(struct Qdisc *sch)
+{
+ struct codel_sched_data *q = qdisc_priv(sch);
+
+ qdisc_reset_queue(sch);
+ codel_vars_init(&q->vars);
+}
+
+static struct Qdisc_ops codel_qdisc_ops __read_mostly = {
+ .id = "codel",
+ .priv_size = sizeof(struct codel_sched_data),
+
+ .enqueue = codel_qdisc_enqueue,
+ .dequeue = codel_qdisc_dequeue,
+ .peek = qdisc_peek_dequeued,
+ .init = codel_init,
+ .reset = codel_reset,
+ .change = codel_change,
+ .dump = codel_dump,
+ .dump_stats = codel_dump_stats,
+ .owner = THIS_MODULE,
+};
+
+static int __init codel_module_init(void)
+{
+ return register_qdisc(&codel_qdisc_ops);
+}
+
+static void __exit codel_module_exit(void)
+{
+ unregister_qdisc(&codel_qdisc_ops);
+}
+
+module_init(codel_module_init)
+module_exit(codel_module_exit)
+
+MODULE_DESCRIPTION("Controlled Delay queue discipline");
+MODULE_AUTHOR("Dave Taht");
+MODULE_AUTHOR("Eric Dumazet");
+MODULE_LICENSE("Dual BSD/GPL");
Code Review / kvmfornfv.git / blobdiff