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  */
sctp_sched_fcfs_set(struct sctp_stream * stream,__u16 sid,__u16 value,gfp_t gfp)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 
sctp_sched_fcfs_get(struct sctp_stream * stream,__u16 sid,__u16 * value)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 
sctp_sched_fcfs_init(struct sctp_stream * stream)38 static int sctp_sched_fcfs_init(struct sctp_stream *stream)
39 {
40 	return 0;
41 }
42 
sctp_sched_fcfs_init_sid(struct sctp_stream * stream,__u16 sid,gfp_t gfp)43 static int sctp_sched_fcfs_init_sid(struct sctp_stream *stream, __u16 sid,
44 				    gfp_t gfp)
45 {
46 	return 0;
47 }
48 
sctp_sched_fcfs_free(struct sctp_stream * stream)49 static void sctp_sched_fcfs_free(struct sctp_stream *stream)
50 {
51 }
52 
sctp_sched_fcfs_enqueue(struct sctp_outq * q,struct sctp_datamsg * msg)53 static void sctp_sched_fcfs_enqueue(struct sctp_outq *q,
54 				    struct sctp_datamsg *msg)
55 {
56 }
57 
sctp_sched_fcfs_dequeue(struct sctp_outq * q)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 
sctp_sched_fcfs_dequeue_done(struct sctp_outq * q,struct sctp_chunk * chunk)81 static void sctp_sched_fcfs_dequeue_done(struct sctp_outq *q,
82 					 struct sctp_chunk *chunk)
83 {
84 }
85 
sctp_sched_fcfs_sched_all(struct sctp_stream * stream)86 static void sctp_sched_fcfs_sched_all(struct sctp_stream *stream)
87 {
88 }
89 
sctp_sched_fcfs_unsched_all(struct sctp_stream * stream)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 
sctp_sched_ops_fcfs_init(void)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 
sctp_sched_ops_register(enum sctp_sched_type sched,struct sctp_sched_ops * sched_ops)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 
sctp_sched_ops_init(void)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 
sctp_sched_set_sched(struct sctp_association * asoc,enum sctp_sched_type sched)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 			struct sctp_stream_out_ext *ext = SCTP_SO(&asoc->stream, i)->ext;
150 
151 			if (!ext)
152 				continue;
153 			memset_after(ext, 0, outq);
154 		}
155 	}
156 
157 	asoc->outqueue.sched = n;
158 	n->init(&asoc->stream);
159 	for (i = 0; i < asoc->stream.outcnt; i++) {
160 		if (!SCTP_SO(&asoc->stream, i)->ext)
161 			continue;
162 
163 		ret = n->init_sid(&asoc->stream, i, GFP_ATOMIC);
164 		if (ret)
165 			goto err;
166 	}
167 
168 	/* We have to requeue all chunks already queued. */
169 	list_for_each_entry(ch, &asoc->outqueue.out_chunk_list, list) {
170 		if (ch->msg == msg)
171 			continue;
172 		msg = ch->msg;
173 		n->enqueue(&asoc->outqueue, msg);
174 	}
175 
176 	return ret;
177 
178 err:
179 	n->free(&asoc->stream);
180 	asoc->outqueue.sched = &sctp_sched_fcfs; /* Always safe */
181 
182 	return ret;
183 }
184 
sctp_sched_get_sched(struct sctp_association * asoc)185 int sctp_sched_get_sched(struct sctp_association *asoc)
186 {
187 	int i;
188 
189 	for (i = 0; i <= SCTP_SS_MAX; i++)
190 		if (asoc->outqueue.sched == sctp_sched_ops[i])
191 			return i;
192 
193 	return 0;
194 }
195 
sctp_sched_set_value(struct sctp_association * asoc,__u16 sid,__u16 value,gfp_t gfp)196 int sctp_sched_set_value(struct sctp_association *asoc, __u16 sid,
197 			 __u16 value, gfp_t gfp)
198 {
199 	if (sid >= asoc->stream.outcnt)
200 		return -EINVAL;
201 
202 	if (!SCTP_SO(&asoc->stream, sid)->ext) {
203 		int ret;
204 
205 		ret = sctp_stream_init_ext(&asoc->stream, sid);
206 		if (ret)
207 			return ret;
208 	}
209 
210 	return asoc->outqueue.sched->set(&asoc->stream, sid, value, gfp);
211 }
212 
sctp_sched_get_value(struct sctp_association * asoc,__u16 sid,__u16 * value)213 int sctp_sched_get_value(struct sctp_association *asoc, __u16 sid,
214 			 __u16 *value)
215 {
216 	if (sid >= asoc->stream.outcnt)
217 		return -EINVAL;
218 
219 	if (!SCTP_SO(&asoc->stream, sid)->ext)
220 		return 0;
221 
222 	return asoc->outqueue.sched->get(&asoc->stream, sid, value);
223 }
224 
sctp_sched_dequeue_done(struct sctp_outq * q,struct sctp_chunk * ch)225 void sctp_sched_dequeue_done(struct sctp_outq *q, struct sctp_chunk *ch)
226 {
227 	if (!list_is_last(&ch->frag_list, &ch->msg->chunks) &&
228 	    !q->asoc->peer.intl_capable) {
229 		struct sctp_stream_out *sout;
230 		__u16 sid;
231 
232 		/* datamsg is not finish, so save it as current one,
233 		 * in case application switch scheduler or a higher
234 		 * priority stream comes in.
235 		 */
236 		sid = sctp_chunk_stream_no(ch);
237 		sout = SCTP_SO(&q->asoc->stream, sid);
238 		q->asoc->stream.out_curr = sout;
239 		return;
240 	}
241 
242 	q->asoc->stream.out_curr = NULL;
243 	q->sched->dequeue_done(q, ch);
244 }
245 
246 /* Auxiliary functions for the schedulers */
sctp_sched_dequeue_common(struct sctp_outq * q,struct sctp_chunk * ch)247 void sctp_sched_dequeue_common(struct sctp_outq *q, struct sctp_chunk *ch)
248 {
249 	list_del_init(&ch->list);
250 	list_del_init(&ch->stream_list);
251 	q->out_qlen -= ch->skb->len;
252 }
253 
sctp_sched_init_sid(struct sctp_stream * stream,__u16 sid,gfp_t gfp)254 int sctp_sched_init_sid(struct sctp_stream *stream, __u16 sid, gfp_t gfp)
255 {
256 	struct sctp_sched_ops *sched = sctp_sched_ops_from_stream(stream);
257 	struct sctp_stream_out_ext *ext = SCTP_SO(stream, sid)->ext;
258 
259 	INIT_LIST_HEAD(&ext->outq);
260 	return sched->init_sid(stream, sid, gfp);
261 }
262 
sctp_sched_ops_from_stream(struct sctp_stream * stream)263 struct sctp_sched_ops *sctp_sched_ops_from_stream(struct sctp_stream *stream)
264 {
265 	struct sctp_association *asoc;
266 
267 	asoc = container_of(stream, struct sctp_association, stream);
268 
269 	return asoc->outqueue.sched;
270 }
271