xref: /openbmc/linux/net/sctp/stream_sched.c (revision b4e18b29)
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(struct sctp_stream *stream)
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 = sctp_sched_fcfs_free,
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 }
128 
129 int sctp_sched_set_sched(struct sctp_association *asoc,
130 			 enum sctp_sched_type sched)
131 {
132 	struct sctp_sched_ops *n = sctp_sched_ops[sched];
133 	struct sctp_sched_ops *old = asoc->outqueue.sched;
134 	struct sctp_datamsg *msg = NULL;
135 	struct sctp_chunk *ch;
136 	int i, ret = 0;
137 
138 	if (old == n)
139 		return ret;
140 
141 	if (sched > SCTP_SS_MAX)
142 		return -EINVAL;
143 
144 	if (old) {
145 		old->free(&asoc->stream);
146 
147 		/* Give the next scheduler a clean slate. */
148 		for (i = 0; i < asoc->stream.outcnt; i++) {
149 			void *p = SCTP_SO(&asoc->stream, i)->ext;
150 
151 			if (!p)
152 				continue;
153 
154 			p += offsetofend(struct sctp_stream_out_ext, outq);
155 			memset(p, 0, sizeof(struct sctp_stream_out_ext) -
156 				     offsetofend(struct sctp_stream_out_ext, outq));
157 		}
158 	}
159 
160 	asoc->outqueue.sched = n;
161 	n->init(&asoc->stream);
162 	for (i = 0; i < asoc->stream.outcnt; i++) {
163 		if (!SCTP_SO(&asoc->stream, i)->ext)
164 			continue;
165 
166 		ret = n->init_sid(&asoc->stream, i, GFP_KERNEL);
167 		if (ret)
168 			goto err;
169 	}
170 
171 	/* We have to requeue all chunks already queued. */
172 	list_for_each_entry(ch, &asoc->outqueue.out_chunk_list, list) {
173 		if (ch->msg == msg)
174 			continue;
175 		msg = ch->msg;
176 		n->enqueue(&asoc->outqueue, msg);
177 	}
178 
179 	return ret;
180 
181 err:
182 	n->free(&asoc->stream);
183 	asoc->outqueue.sched = &sctp_sched_fcfs; /* Always safe */
184 
185 	return ret;
186 }
187 
188 int sctp_sched_get_sched(struct sctp_association *asoc)
189 {
190 	int i;
191 
192 	for (i = 0; i <= SCTP_SS_MAX; i++)
193 		if (asoc->outqueue.sched == sctp_sched_ops[i])
194 			return i;
195 
196 	return 0;
197 }
198 
199 int sctp_sched_set_value(struct sctp_association *asoc, __u16 sid,
200 			 __u16 value, gfp_t gfp)
201 {
202 	if (sid >= asoc->stream.outcnt)
203 		return -EINVAL;
204 
205 	if (!SCTP_SO(&asoc->stream, sid)->ext) {
206 		int ret;
207 
208 		ret = sctp_stream_init_ext(&asoc->stream, sid);
209 		if (ret)
210 			return ret;
211 	}
212 
213 	return asoc->outqueue.sched->set(&asoc->stream, sid, value, gfp);
214 }
215 
216 int sctp_sched_get_value(struct sctp_association *asoc, __u16 sid,
217 			 __u16 *value)
218 {
219 	if (sid >= asoc->stream.outcnt)
220 		return -EINVAL;
221 
222 	if (!SCTP_SO(&asoc->stream, sid)->ext)
223 		return 0;
224 
225 	return asoc->outqueue.sched->get(&asoc->stream, sid, value);
226 }
227 
228 void sctp_sched_dequeue_done(struct sctp_outq *q, struct sctp_chunk *ch)
229 {
230 	if (!list_is_last(&ch->frag_list, &ch->msg->chunks) &&
231 	    !q->asoc->peer.intl_capable) {
232 		struct sctp_stream_out *sout;
233 		__u16 sid;
234 
235 		/* datamsg is not finish, so save it as current one,
236 		 * in case application switch scheduler or a higher
237 		 * priority stream comes in.
238 		 */
239 		sid = sctp_chunk_stream_no(ch);
240 		sout = SCTP_SO(&q->asoc->stream, sid);
241 		q->asoc->stream.out_curr = sout;
242 		return;
243 	}
244 
245 	q->asoc->stream.out_curr = NULL;
246 	q->sched->dequeue_done(q, ch);
247 }
248 
249 /* Auxiliary functions for the schedulers */
250 void sctp_sched_dequeue_common(struct sctp_outq *q, struct sctp_chunk *ch)
251 {
252 	list_del_init(&ch->list);
253 	list_del_init(&ch->stream_list);
254 	q->out_qlen -= ch->skb->len;
255 }
256 
257 int sctp_sched_init_sid(struct sctp_stream *stream, __u16 sid, gfp_t gfp)
258 {
259 	struct sctp_sched_ops *sched = sctp_sched_ops_from_stream(stream);
260 	struct sctp_stream_out_ext *ext = SCTP_SO(stream, sid)->ext;
261 
262 	INIT_LIST_HEAD(&ext->outq);
263 	return sched->init_sid(stream, sid, gfp);
264 }
265 
266 struct sctp_sched_ops *sctp_sched_ops_from_stream(struct sctp_stream *stream)
267 {
268 	struct sctp_association *asoc;
269 
270 	asoc = container_of(stream, struct sctp_association, stream);
271 
272 	return asoc->outqueue.sched;
273 }
274