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 */
25 static int sctp_sched_fcfs_set(struct sctp_stream *stream, __u16 sid,
26 __u16 value, gfp_t gfp)
27 {
28 return 0;
29 }
30
31 static int sctp_sched_fcfs_get(struct sctp_stream *stream, __u16 sid,
32 __u16 *value)
33 {
34 *value = 0;
35 return 0;
36 }
37
38 static int sctp_sched_fcfs_init(struct sctp_stream *stream)
39 {
40 return 0;
41 }
42
43 static int sctp_sched_fcfs_init_sid(struct sctp_stream *stream, __u16 sid,
44 gfp_t gfp)
45 {
46 return 0;
47 }
48
49 static void sctp_sched_fcfs_free_sid(struct sctp_stream *stream, __u16 sid)
50 {
51 }
52
53 static void sctp_sched_fcfs_enqueue(struct sctp_outq *q,
54 struct sctp_datamsg *msg)
55 {
56 }
57
58 static 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(&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
77 out:
78 return ch;
79 }
80
81 static void sctp_sched_fcfs_dequeue_done(struct sctp_outq *q,
82 struct sctp_chunk *chunk)
83 {
84 }
85
86 static void sctp_sched_fcfs_sched_all(struct sctp_stream *stream)
87 {
88 }
89
90 static void sctp_sched_fcfs_unsched_all(struct sctp_stream *stream)
91 {
92 }
93
94 static 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
107 static void sctp_sched_ops_fcfs_init(void)
108 {
109 sctp_sched_ops_register(SCTP_SS_FCFS, &sctp_sched_fcfs);
110 }
111
112 /* API to other parts of the stack */
113
114 static struct sctp_sched_ops *sctp_sched_ops[SCTP_SS_MAX + 1];
115
116 void 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
122 void 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
131 static 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
148 int 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(&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
188 err:
189 sctp_sched_free_sched(&asoc->stream);
190 asoc->outqueue.sched = &sctp_sched_fcfs; /* Always safe */
191
192 return ret;
193 }
194
195 int 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
206 int 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(&asoc->stream, sid);
216 if (ret)
217 return ret;
218 }
219
220 return asoc->outqueue.sched->set(&asoc->stream, sid, value, gfp);
221 }
222
223 int 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
235 void sctp_sched_dequeue_done(struct sctp_outq *q, struct sctp_chunk *ch)
236 {
237 if (!list_is_last(&ch->frag_list, &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 */
257 void sctp_sched_dequeue_common(struct sctp_outq *q, struct sctp_chunk *ch)
258 {
259 list_del_init(&ch->list);
260 list_del_init(&ch->stream_list);
261 q->out_qlen -= ch->skb->len;
262 }
263
264 int 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(&ext->outq);
270 return sched->init_sid(stream, sid, gfp);
271 }
272
273 struct 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
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