1// SPDX-License-Identifier: GPL-2.0-or-later
2/* SCTP kernel implementation
3 * (C) Copyright Red Hat Inc. 2017
4 *
5 * This file is part of the SCTP kernel implementation
6 *
7 * These functions manipulate sctp stream queue/scheduling.
8 *
9 * Please send any bug reports or fixes you make to the
10 * email addresched(es):
11 * lksctp developers <linux-sctp@vger.kernel.org>
12 *
13 * Written or modified by:
14 * Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
15 */
16
17#include <linux/list.h>
18#include <net/sctp/sctp.h>
19#include <net/sctp/sm.h>
20#include <net/sctp/stream_sched.h>
21
22/* First Come First Serve (a.k.a. FIFO)
23 * RFC DRAFT ndata Section 3.1
24 */
25static int sctp_sched_fcfs_set(struct sctp_stream *stream, __u16 sid,
26 __u16 value, gfp_t gfp)
27{
28 return 0;
29}
30
31static int sctp_sched_fcfs_get(struct sctp_stream *stream, __u16 sid,
32 __u16 *value)
33{
34 *value = 0;
35 return 0;
36}
37
38static int sctp_sched_fcfs_init(struct sctp_stream *stream)
39{
40 return 0;
41}
42
43static int sctp_sched_fcfs_init_sid(struct sctp_stream *stream, __u16 sid,
44 gfp_t gfp)
45{
46 return 0;
47}
48
49static void sctp_sched_fcfs_free_sid(struct sctp_stream *stream, __u16 sid)
50{
51}
52
53static void sctp_sched_fcfs_enqueue(struct sctp_outq *q,
54 struct sctp_datamsg *msg)
55{
56}
57
58static struct sctp_chunk *sctp_sched_fcfs_dequeue(struct sctp_outq *q)
59{
60 struct sctp_stream *stream = &q->asoc->stream;
61 struct sctp_chunk *ch = NULL;
62 struct list_head *entry;
63
64 if (list_empty(head: &q->out_chunk_list))
65 goto out;
66
67 if (stream->out_curr) {
68 ch = list_entry(stream->out_curr->ext->outq.next,
69 struct sctp_chunk, stream_list);
70 } else {
71 entry = q->out_chunk_list.next;
72 ch = list_entry(entry, struct sctp_chunk, list);
73 }
74
75 sctp_sched_dequeue_common(q, ch);
76
77out:
78 return ch;
79}
80
81static void sctp_sched_fcfs_dequeue_done(struct sctp_outq *q,
82 struct sctp_chunk *chunk)
83{
84}
85
86static void sctp_sched_fcfs_sched_all(struct sctp_stream *stream)
87{
88}
89
90static void sctp_sched_fcfs_unsched_all(struct sctp_stream *stream)
91{
92}
93
94static struct sctp_sched_ops sctp_sched_fcfs = {
95 .set = sctp_sched_fcfs_set,
96 .get = sctp_sched_fcfs_get,
97 .init = sctp_sched_fcfs_init,
98 .init_sid = sctp_sched_fcfs_init_sid,
99 .free_sid = sctp_sched_fcfs_free_sid,
100 .enqueue = sctp_sched_fcfs_enqueue,
101 .dequeue = sctp_sched_fcfs_dequeue,
102 .dequeue_done = sctp_sched_fcfs_dequeue_done,
103 .sched_all = sctp_sched_fcfs_sched_all,
104 .unsched_all = sctp_sched_fcfs_unsched_all,
105};
106
107static void sctp_sched_ops_fcfs_init(void)
108{
109 sctp_sched_ops_register(sched: SCTP_SS_FCFS, sched_ops: &sctp_sched_fcfs);
110}
111
112/* API to other parts of the stack */
113
114static struct sctp_sched_ops *sctp_sched_ops[SCTP_SS_MAX + 1];
115
116void sctp_sched_ops_register(enum sctp_sched_type sched,
117 struct sctp_sched_ops *sched_ops)
118{
119 sctp_sched_ops[sched] = sched_ops;
120}
121
122void sctp_sched_ops_init(void)
123{
124 sctp_sched_ops_fcfs_init();
125 sctp_sched_ops_prio_init();
126 sctp_sched_ops_rr_init();
127 sctp_sched_ops_fc_init();
128 sctp_sched_ops_wfq_init();
129}
130
131static void sctp_sched_free_sched(struct sctp_stream *stream)
132{
133 struct sctp_sched_ops *sched = sctp_sched_ops_from_stream(stream);
134 struct sctp_stream_out_ext *soute;
135 int i;
136
137 sched->unsched_all(stream);
138 for (i = 0; i < stream->outcnt; i++) {
139 soute = SCTP_SO(stream, i)->ext;
140 if (!soute)
141 continue;
142 sched->free_sid(stream, i);
143 /* Give the next scheduler a clean slate. */
144 memset_after(soute, 0, outq);
145 }
146}
147
148int sctp_sched_set_sched(struct sctp_association *asoc,
149 enum sctp_sched_type sched)
150{
151 struct sctp_sched_ops *old = asoc->outqueue.sched;
152 struct sctp_datamsg *msg = NULL;
153 struct sctp_sched_ops *n;
154 struct sctp_chunk *ch;
155 int i, ret = 0;
156
157 if (sched > SCTP_SS_MAX)
158 return -EINVAL;
159
160 n = sctp_sched_ops[sched];
161 if (old == n)
162 return ret;
163
164 if (old)
165 sctp_sched_free_sched(stream: &asoc->stream);
166
167 asoc->outqueue.sched = n;
168 n->init(&asoc->stream);
169 for (i = 0; i < asoc->stream.outcnt; i++) {
170 if (!SCTP_SO(&asoc->stream, i)->ext)
171 continue;
172
173 ret = n->init_sid(&asoc->stream, i, GFP_ATOMIC);
174 if (ret)
175 goto err;
176 }
177
178 /* We have to requeue all chunks already queued. */
179 list_for_each_entry(ch, &asoc->outqueue.out_chunk_list, list) {
180 if (ch->msg == msg)
181 continue;
182 msg = ch->msg;
183 n->enqueue(&asoc->outqueue, msg);
184 }
185
186 return ret;
187
188err:
189 sctp_sched_free_sched(stream: &asoc->stream);
190 asoc->outqueue.sched = &sctp_sched_fcfs; /* Always safe */
191
192 return ret;
193}
194
195int sctp_sched_get_sched(struct sctp_association *asoc)
196{
197 int i;
198
199 for (i = 0; i <= SCTP_SS_MAX; i++)
200 if (asoc->outqueue.sched == sctp_sched_ops[i])
201 return i;
202
203 return 0;
204}
205
206int sctp_sched_set_value(struct sctp_association *asoc, __u16 sid,
207 __u16 value, gfp_t gfp)
208{
209 if (sid >= asoc->stream.outcnt)
210 return -EINVAL;
211
212 if (!SCTP_SO(&asoc->stream, sid)->ext) {
213 int ret;
214
215 ret = sctp_stream_init_ext(stream: &asoc->stream, sid);
216 if (ret)
217 return ret;
218 }
219
220 return asoc->outqueue.sched->set(&asoc->stream, sid, value, gfp);
221}
222
223int sctp_sched_get_value(struct sctp_association *asoc, __u16 sid,
224 __u16 *value)
225{
226 if (sid >= asoc->stream.outcnt)
227 return -EINVAL;
228
229 if (!SCTP_SO(&asoc->stream, sid)->ext)
230 return 0;
231
232 return asoc->outqueue.sched->get(&asoc->stream, sid, value);
233}
234
235void sctp_sched_dequeue_done(struct sctp_outq *q, struct sctp_chunk *ch)
236{
237 if (!list_is_last(list: &ch->frag_list, head: &ch->msg->chunks) &&
238 !q->asoc->peer.intl_capable) {
239 struct sctp_stream_out *sout;
240 __u16 sid;
241
242 /* datamsg is not finish, so save it as current one,
243 * in case application switch scheduler or a higher
244 * priority stream comes in.
245 */
246 sid = sctp_chunk_stream_no(ch);
247 sout = SCTP_SO(&q->asoc->stream, sid);
248 q->asoc->stream.out_curr = sout;
249 return;
250 }
251
252 q->asoc->stream.out_curr = NULL;
253 q->sched->dequeue_done(q, ch);
254}
255
256/* Auxiliary functions for the schedulers */
257void sctp_sched_dequeue_common(struct sctp_outq *q, struct sctp_chunk *ch)
258{
259 list_del_init(entry: &ch->list);
260 list_del_init(entry: &ch->stream_list);
261 q->out_qlen -= ch->skb->len;
262}
263
264int sctp_sched_init_sid(struct sctp_stream *stream, __u16 sid, gfp_t gfp)
265{
266 struct sctp_sched_ops *sched = sctp_sched_ops_from_stream(stream);
267 struct sctp_stream_out_ext *ext = SCTP_SO(stream, sid)->ext;
268
269 INIT_LIST_HEAD(list: &ext->outq);
270 return sched->init_sid(stream, sid, gfp);
271}
272
273struct sctp_sched_ops *sctp_sched_ops_from_stream(struct sctp_stream *stream)
274{
275 struct sctp_association *asoc;
276
277 asoc = container_of(stream, struct sctp_association, stream);
278
279 return asoc->outqueue.sched;
280}
281

source code of linux/net/sctp/stream_sched.c