1 files changed, 152 insertions, 0 deletions
diff --git a/net/sched/sch_fifo.c b/net/sched/sch_fifo.c
new file mode 100644
index 0000000..23d258b
--- /dev/null
+++ b/net/sched/sch_fifo.c
@@ -0,0 +1,152 @@
+/*
+ * net/sched/sch_fifo.c	The simplest FIFO queue.
+ *
+ *		This program is free software; you can redistribute it and/or
+ *		modify it under the terms of the GNU General Public License
+ *		as published by the Free Software Foundation; either version
+ *		2 of the License, or (at your option) any later version.
+ *
+ * Authors:	Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
+ */
+
+#include <linux/module.h>
+#include <linux/types.h>
+#include <linux/kernel.h>
+#include <linux/errno.h>
+#include <linux/skbuff.h>
+#include <net/pkt_sched.h>
+
+/* 1 band FIFO pseudo-"scheduler" */
+
+struct fifo_sched_data
+{
+	u32 limit;
+};
+
+static int bfifo_enqueue(struct sk_buff *skb, struct Qdisc* sch)
+{
+	struct fifo_sched_data *q = qdisc_priv(sch);
+
+	if (likely(sch->qstats.backlog + qdisc_pkt_len(skb) <= q->limit))
+		return qdisc_enqueue_tail(skb, sch);
+
+	return qdisc_reshape_fail(skb, sch);
+}
+
+static int pfifo_enqueue(struct sk_buff *skb, struct Qdisc* sch)
+{
+	struct fifo_sched_data *q = qdisc_priv(sch);
+
+	if (likely(skb_queue_len(&sch->q) < q->limit))
+		return qdisc_enqueue_tail(skb, sch);
+
+	return qdisc_reshape_fail(skb, sch);
+}
+
+static int fifo_init(struct Qdisc *sch, struct nlattr *opt)
+{
+	struct fifo_sched_data *q = qdisc_priv(sch);
+
+	if (opt == NULL) {
+		u32 limit = qdisc_dev(sch)->tx_queue_len ? : 1;
+
+		if (sch->ops == &bfifo_qdisc_ops)
+			limit *= qdisc_dev(sch)->mtu;
+
+		q->limit = limit;
+	} else {
+		struct tc_fifo_qopt *ctl = nla_data(opt);
+
+		if (nla_len(opt) < sizeof(*ctl))
+			return -EINVAL;
+
+		q->limit = ctl->limit;
+	}
+
+	return 0;
+}
+
+static int fifo_dump(struct Qdisc *sch, struct sk_buff *skb)
+{
+	struct fifo_sched_data *q = qdisc_priv(sch);
+	struct tc_fifo_qopt opt = { .limit = q->limit };
+
+	NLA_PUT(skb, TCA_OPTIONS, sizeof(opt), &opt);
+	return skb->len;
+
+nla_put_failure:
+	return -1;
+}
+
+struct Qdisc_ops pfifo_qdisc_ops __read_mostly = {
+	.id		=	"pfifo",
+	.priv_size	=	sizeof(struct fifo_sched_data),
+	.enqueue	=	pfifo_enqueue,
+	.dequeue	=	qdisc_dequeue_head,
+	.requeue	=	qdisc_requeue,
+	.drop		=	qdisc_queue_drop,
+	.init		=	fifo_init,
+	.reset		=	qdisc_reset_queue,
+	.change		=	fifo_init,
+	.dump		=	fifo_dump,
+	.owner		=	THIS_MODULE,
+};
+EXPORT_SYMBOL(pfifo_qdisc_ops);
+
+struct Qdisc_ops bfifo_qdisc_ops __read_mostly = {
+	.id		=	"bfifo",
+	.priv_size	=	sizeof(struct fifo_sched_data),
+	.enqueue	=	bfifo_enqueue,
+	.dequeue	=	qdisc_dequeue_head,
+	.requeue	=	qdisc_requeue,
+	.drop		=	qdisc_queue_drop,
+	.init		=	fifo_init,
+	.reset		=	qdisc_reset_queue,
+	.change		=	fifo_init,
+	.dump		=	fifo_dump,
+	.owner		=	THIS_MODULE,
+};
+EXPORT_SYMBOL(bfifo_qdisc_ops);
+
+/* Pass size change message down to embedded FIFO */
+int fifo_set_limit(struct Qdisc *q, unsigned int limit)
+{
+	struct nlattr *nla;
+	int ret = -ENOMEM;
+
+	/* Hack to avoid sending change message to non-FIFO */
+	if (strncmp(q->ops->id + 1, "fifo", 4) != 0)
+		return 0;
+
+	nla = kmalloc(nla_attr_size(sizeof(struct tc_fifo_qopt)), GFP_KERNEL);
+	if (nla) {
+		nla->nla_type = RTM_NEWQDISC;
+		nla->nla_len = nla_attr_size(sizeof(struct tc_fifo_qopt));
+		((struct tc_fifo_qopt *)nla_data(nla))->limit = limit;
+
+		ret = q->ops->change(q, nla);
+		kfree(nla);
+	}
+	return ret;
+}
+EXPORT_SYMBOL(fifo_set_limit);
+
+struct Qdisc *fifo_create_dflt(struct Qdisc *sch, struct Qdisc_ops *ops,
+			       unsigned int limit)
+{
+	struct Qdisc *q;
+	int err = -ENOMEM;
+
+	q = qdisc_create_dflt(qdisc_dev(sch), sch->dev_queue,
+			      ops, TC_H_MAKE(sch->handle, 1));
+	if (q) {
+		err = fifo_set_limit(q, limit);
+		if (err < 0) {
+			qdisc_destroy(q);
+			q = NULL;
+		}
+	}
+
+	return q ? : ERR_PTR(err);
+}
+EXPORT_SYMBOL(fifo_create_dflt);