// SPDX-License-Identifier: GPL-2.0-or-later
/* SCTP kernel implementation
* (C) Copyright Red Hat Inc. 2022
*
* This file is part of the SCTP kernel implementation
*
* These functions manipulate sctp stream queue/scheduling.
*
* Please send any bug reports or fixes you make to the
* email addresched(es):
* lksctp developers <[email protected]>
*
* Written or modified by:
* Xin Long <[email protected]>
*/
#include <linux/list.h>
#include <net/sctp/sctp.h>
#include <net/sctp/sm.h>
#include <net/sctp/stream_sched.h>
/* Fair Capacity and Weighted Fair Queueing handling
* RFC 8260 section 3.5 and 3.6
*/
static void sctp_sched_fc_unsched_all(struct sctp_stream *stream);
static int sctp_sched_wfq_set(struct sctp_stream *stream, __u16 sid,
__u16 weight, gfp_t gfp)
{
struct sctp_stream_out_ext *soute = SCTP_SO(stream, sid)->ext;
if (!weight)
return -EINVAL;
soute->fc_weight = weight;
return 0;
}
static int sctp_sched_wfq_get(struct sctp_stream *stream, __u16 sid,
__u16 *value)
{
struct sctp_stream_out_ext *soute = SCTP_SO(stream, sid)->ext;
*value = soute->fc_weight;
return 0;
}
static int sctp_sched_fc_set(struct sctp_stream *stream, __u16 sid,
__u16 weight, gfp_t gfp)
{
return 0;
}
static int sctp_sched_fc_get(struct sctp_stream *stream, __u16 sid,
__u16 *value)
{
return 0;
}
static int sctp_sched_fc_init(struct sctp_stream *stream)
{
INIT_LIST_HEAD(&stream->fc_list);
return 0;
}
static int sctp_sched_fc_init_sid(struct sctp_stream *stream, __u16 sid,
gfp_t gfp)
{
struct sctp_stream_out_ext *soute = SCTP_SO(stream, sid)->ext;
INIT_LIST_HEAD(&soute->fc_list);
soute->fc_length = 0;
soute->fc_weight = 1;
return 0;
}
static void sctp_sched_fc_free_sid(struct sctp_stream *stream, __u16 sid)
{
}
static void sctp_sched_fc_sched(struct sctp_stream *stream,
struct sctp_stream_out_ext *soute)
{
struct sctp_stream_out_ext *pos;
if (!list_empty(&soute->fc_list))
return;
list_for_each_entry(pos, &stream->fc_list, fc_list)
if ((__u64)pos->fc_length * soute->fc_weight >=
(__u64)soute->fc_length * pos->fc_weight)
break;
list_add_tail(&soute->fc_list, &pos->fc_list);
}
static void sctp_sched_fc_enqueue(struct sctp_outq *q,
struct sctp_datamsg *msg)
{
struct sctp_stream *stream;
struct sctp_chunk *ch;
__u16 sid;
ch = list_first_entry(&msg->chunks, struct sctp_chunk, frag_list);
sid = sctp_chunk_stream_no(ch);
stream = &q->asoc->stream;
sctp_sched_fc_sched(stream, SCTP_SO(stream, sid)->ext);
}
static struct sctp_chunk *sctp_sched_fc_dequeue(struct sctp_outq *q)
{
struct sctp_stream *stream = &q->asoc->stream;
struct sctp_stream_out_ext *soute;
struct sctp_chunk *ch;
/* Bail out quickly if queue is empty */
if (list_empty(&q->out_chunk_list))
return NULL;
/* Find which chunk is next */
if (stream->out_curr)
soute = stream->out_curr->ext;
else
soute = list_entry(stream->fc_list.next, struct sctp_stream_out_ext, fc_list);
ch = list_entry(soute->outq.next, struct sctp_chunk, stream_list);
sctp_sched_dequeue_common(q, ch);
return ch;
}
static void sctp_sched_fc_dequeue_done(struct sctp_outq *q,
struct sctp_chunk *ch)
{
struct sctp_stream *stream = &q->asoc->stream;
struct sctp_stream_out_ext *soute, *pos;
__u16 sid, i;
sid = sctp_chunk_stream_no(ch);
soute = SCTP_SO(stream, sid)->ext;
/* reduce all fc_lengths by U32_MAX / 4 if the current fc_length overflows. */
if (soute->fc_length > U32_MAX - ch->skb->len) {
for (i = 0; i < stream->outcnt; i++) {
pos = SCTP_SO(stream, i)->ext;
if (!pos)
continue;
if (pos->fc_length <= (U32_MAX >> 2)) {
pos->fc_length = 0;
continue;
}
pos->fc_length -= (U32_MAX >> 2);
}
}
soute->fc_length += ch->skb->len;
if (list_empty(&soute->outq)) {
list_del_init(&soute->fc_list);
return;
}
pos = soute;
list_for_each_entry_continue(pos, &stream->fc_list, fc_list)
if ((__u64)pos->fc_length * soute->fc_weight >=
(__u64)soute->fc_length * pos->fc_weight)
break;
list_move_tail(&soute->fc_list, &pos->fc_list);
}
static void sctp_sched_fc_sched_all(struct sctp_stream *stream)
{
struct sctp_association *asoc;
struct sctp_chunk *ch;
asoc = container_of(stream, struct sctp_association, stream);
list_for_each_entry(ch, &asoc->outqueue.out_chunk_list, list) {
__u16 sid = sctp_chunk_stream_no(ch);
if (SCTP_SO(stream, sid)->ext)
sctp_sched_fc_sched(stream, SCTP_SO(stream, sid)->ext);
}
}
static void sctp_sched_fc_unsched_all(struct sctp_stream *stream)
{
struct sctp_stream_out_ext *soute, *tmp;
list_for_each_entry_safe(soute, tmp, &stream->fc_list, fc_list)
list_del_init(&soute->fc_list);
}
static struct sctp_sched_ops sctp_sched_fc = {
.set = sctp_sched_fc_set,
.get = sctp_sched_fc_get,
.init = sctp_sched_fc_init,
.init_sid = sctp_sched_fc_init_sid,
.free_sid = sctp_sched_fc_free_sid,
.enqueue = sctp_sched_fc_enqueue,
.dequeue = sctp_sched_fc_dequeue,
.dequeue_done = sctp_sched_fc_dequeue_done,
.sched_all = sctp_sched_fc_sched_all,
.unsched_all = sctp_sched_fc_unsched_all,
};
void sctp_sched_ops_fc_init(void)
{
sctp_sched_ops_register(SCTP_SS_FC, &sctp_sched_fc);
}
static struct sctp_sched_ops sctp_sched_wfq = {
.set = sctp_sched_wfq_set,
.get = sctp_sched_wfq_get,
.init = sctp_sched_fc_init,
.init_sid = sctp_sched_fc_init_sid,
.free_sid = sctp_sched_fc_free_sid,
.enqueue = sctp_sched_fc_enqueue,
.dequeue = sctp_sched_fc_dequeue,
.dequeue_done = sctp_sched_fc_dequeue_done,
.sched_all = sctp_sched_fc_sched_all,
.unsched_all = sctp_sched_fc_unsched_all,
};
void sctp_sched_ops_wfq_init(void)
{
sctp_sched_ops_register(SCTP_SS_WFQ, &sctp_sched_wfq);
}