xref: /openbmc/linux/net/sctp/stream_sched.c (revision 82e6fdd6) 
1 /* SCTP kernel implementation
2  * (C) Copyright Red Hat Inc. 2017
3  *
4  * This file is part of the SCTP kernel implementation
5  *
6  * These functions manipulate sctp stream queue/scheduling.
7  *
8  * This SCTP implementation is free software;
9  * you can redistribute it and/or modify it under the terms of
10  * the GNU General Public License as published by
11  * the Free Software Foundation; either version 2, or (at your option)
12  * any later version.
13  *
14  * This SCTP implementation is distributed in the hope that it
15  * will be useful, but WITHOUT ANY WARRANTY; without even the implied
16  *                 ************************
17  * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
18  * See the GNU General Public License for more details.
19  *
20  * You should have received a copy of the GNU General Public License
21  * along with GNU CC; see the file COPYING.  If not, see
22  * <http://www.gnu.org/licenses/>.
23  *
24  * Please send any bug reports or fixes you make to the
25  * email addresched(es):
26  *    lksctp developers <linux-sctp@vger.kernel.org>
27  *
28  * Written or modified by:
29  *    Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
30  */
31 
32 #include <linux/list.h>
33 #include <net/sctp/sctp.h>
34 #include <net/sctp/sm.h>
35 #include <net/sctp/stream_sched.h>
36 
37 /* First Come First Serve (a.k.a. FIFO)
38  * RFC DRAFT ndata Section 3.1
39  */
40 static int sctp_sched_fcfs_set(struct sctp_stream *stream, __u16 sid,
41 			       __u16 value, gfp_t gfp)
42 {
43 	return 0;
44 }
45 
46 static int sctp_sched_fcfs_get(struct sctp_stream *stream, __u16 sid,
47 			       __u16 *value)
48 {
49 	*value = 0;
50 	return 0;
51 }
52 
53 static int sctp_sched_fcfs_init(struct sctp_stream *stream)
54 {
55 	return 0;
56 }
57 
58 static int sctp_sched_fcfs_init_sid(struct sctp_stream *stream, __u16 sid,
59 				    gfp_t gfp)
60 {
61 	return 0;
62 }
63 
64 static void sctp_sched_fcfs_free(struct sctp_stream *stream)
65 {
66 }
67 
68 static void sctp_sched_fcfs_enqueue(struct sctp_outq *q,
69 				    struct sctp_datamsg *msg)
70 {
71 }
72 
73 static struct sctp_chunk *sctp_sched_fcfs_dequeue(struct sctp_outq *q)
74 {
75 	struct sctp_stream *stream = &q->asoc->stream;
76 	struct sctp_chunk *ch = NULL;
77 	struct list_head *entry;
78 
79 	if (list_empty(&q->out_chunk_list))
80 		goto out;
81 
82 	if (stream->out_curr) {
83 		ch = list_entry(stream->out_curr->ext->outq.next,
84 				struct sctp_chunk, stream_list);
85 	} else {
86 		entry = q->out_chunk_list.next;
87 		ch = list_entry(entry, struct sctp_chunk, list);
88 	}
89 
90 	sctp_sched_dequeue_common(q, ch);
91 
92 out:
93 	return ch;
94 }
95 
96 static void sctp_sched_fcfs_dequeue_done(struct sctp_outq *q,
97 					 struct sctp_chunk *chunk)
98 {
99 }
100 
101 static void sctp_sched_fcfs_sched_all(struct sctp_stream *stream)
102 {
103 }
104 
105 static void sctp_sched_fcfs_unsched_all(struct sctp_stream *stream)
106 {
107 }
108 
109 static struct sctp_sched_ops sctp_sched_fcfs = {
110 	.set = sctp_sched_fcfs_set,
111 	.get = sctp_sched_fcfs_get,
112 	.init = sctp_sched_fcfs_init,
113 	.init_sid = sctp_sched_fcfs_init_sid,
114 	.free = sctp_sched_fcfs_free,
115 	.enqueue = sctp_sched_fcfs_enqueue,
116 	.dequeue = sctp_sched_fcfs_dequeue,
117 	.dequeue_done = sctp_sched_fcfs_dequeue_done,
118 	.sched_all = sctp_sched_fcfs_sched_all,
119 	.unsched_all = sctp_sched_fcfs_unsched_all,
120 };
121 
122 static void sctp_sched_ops_fcfs_init(void)
123 {
124 	sctp_sched_ops_register(SCTP_SS_FCFS, &sctp_sched_fcfs);
125 }
126 
127 /* API to other parts of the stack */
128 
129 static struct sctp_sched_ops *sctp_sched_ops[SCTP_SS_MAX + 1];
130 
131 void sctp_sched_ops_register(enum sctp_sched_type sched,
132 			     struct sctp_sched_ops *sched_ops)
133 {
134 	sctp_sched_ops[sched] = sched_ops;
135 }
136 
137 void sctp_sched_ops_init(void)
138 {
139 	sctp_sched_ops_fcfs_init();
140 	sctp_sched_ops_prio_init();
141 	sctp_sched_ops_rr_init();
142 }
143 
144 int sctp_sched_set_sched(struct sctp_association *asoc,
145 			 enum sctp_sched_type sched)
146 {
147 	struct sctp_sched_ops *n = sctp_sched_ops[sched];
148 	struct sctp_sched_ops *old = asoc->outqueue.sched;
149 	struct sctp_datamsg *msg = NULL;
150 	struct sctp_chunk *ch;
151 	int i, ret = 0;
152 
153 	if (old == n)
154 		return ret;
155 
156 	if (sched > SCTP_SS_MAX)
157 		return -EINVAL;
158 
159 	if (old) {
160 		old->free(&asoc->stream);
161 
162 		/* Give the next scheduler a clean slate. */
163 		for (i = 0; i < asoc->stream.outcnt; i++) {
164 			void *p = asoc->stream.out[i].ext;
165 
166 			if (!p)
167 				continue;
168 
169 			p += offsetofend(struct sctp_stream_out_ext, outq);
170 			memset(p, 0, sizeof(struct sctp_stream_out_ext) -
171 				     offsetofend(struct sctp_stream_out_ext, outq));
172 		}
173 	}
174 
175 	asoc->outqueue.sched = n;
176 	n->init(&asoc->stream);
177 	for (i = 0; i < asoc->stream.outcnt; i++) {
178 		if (!asoc->stream.out[i].ext)
179 			continue;
180 
181 		ret = n->init_sid(&asoc->stream, i, GFP_KERNEL);
182 		if (ret)
183 			goto err;
184 	}
185 
186 	/* We have to requeue all chunks already queued. */
187 	list_for_each_entry(ch, &asoc->outqueue.out_chunk_list, list) {
188 		if (ch->msg == msg)
189 			continue;
190 		msg = ch->msg;
191 		n->enqueue(&asoc->outqueue, msg);
192 	}
193 
194 	return ret;
195 
196 err:
197 	n->free(&asoc->stream);
198 	asoc->outqueue.sched = &sctp_sched_fcfs; /* Always safe */
199 
200 	return ret;
201 }
202 
203 int sctp_sched_get_sched(struct sctp_association *asoc)
204 {
205 	int i;
206 
207 	for (i = 0; i <= SCTP_SS_MAX; i++)
208 		if (asoc->outqueue.sched == sctp_sched_ops[i])
209 			return i;
210 
211 	return 0;
212 }
213 
214 int sctp_sched_set_value(struct sctp_association *asoc, __u16 sid,
215 			 __u16 value, gfp_t gfp)
216 {
217 	if (sid >= asoc->stream.outcnt)
218 		return -EINVAL;
219 
220 	if (!asoc->stream.out[sid].ext) {
221 		int ret;
222 
223 		ret = sctp_stream_init_ext(&asoc->stream, sid);
224 		if (ret)
225 			return ret;
226 	}
227 
228 	return asoc->outqueue.sched->set(&asoc->stream, sid, value, gfp);
229 }
230 
231 int sctp_sched_get_value(struct sctp_association *asoc, __u16 sid,
232 			 __u16 *value)
233 {
234 	if (sid >= asoc->stream.outcnt)
235 		return -EINVAL;
236 
237 	if (!asoc->stream.out[sid].ext)
238 		return 0;
239 
240 	return asoc->outqueue.sched->get(&asoc->stream, sid, value);
241 }
242 
243 void sctp_sched_dequeue_done(struct sctp_outq *q, struct sctp_chunk *ch)
244 {
245 	if (!list_is_last(&ch->frag_list, &ch->msg->chunks) &&
246 	    !q->asoc->intl_enable) {
247 		struct sctp_stream_out *sout;
248 		__u16 sid;
249 
250 		/* datamsg is not finish, so save it as current one,
251 		 * in case application switch scheduler or a higher
252 		 * priority stream comes in.
253 		 */
254 		sid = sctp_chunk_stream_no(ch);
255 		sout = &q->asoc->stream.out[sid];
256 		q->asoc->stream.out_curr = sout;
257 		return;
258 	}
259 
260 	q->asoc->stream.out_curr = NULL;
261 	q->sched->dequeue_done(q, ch);
262 }
263 
264 /* Auxiliary functions for the schedulers */
265 void sctp_sched_dequeue_common(struct sctp_outq *q, struct sctp_chunk *ch)
266 {
267 	list_del_init(&ch->list);
268 	list_del_init(&ch->stream_list);
269 	q->out_qlen -= ch->skb->len;
270 }
271 
272 int sctp_sched_init_sid(struct sctp_stream *stream, __u16 sid, gfp_t gfp)
273 {
274 	struct sctp_sched_ops *sched = sctp_sched_ops_from_stream(stream);
275 
276 	INIT_LIST_HEAD(&stream->out[sid].ext->outq);
277 	return sched->init_sid(stream, sid, gfp);
278 }
279 
280 struct sctp_sched_ops *sctp_sched_ops_from_stream(struct sctp_stream *stream)
281 {
282 	struct sctp_association *asoc;
283 
284 	asoc = container_of(stream, struct sctp_association, stream);
285 
286 	return asoc->outqueue.sched;
287 }
288