net/sctp/stream_sched.c

   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_free(struct sctp_stream *stream)
  54 {
  55 }
  56
  57 static void sctp_sched_fcfs_enqueue(struct sctp_outq *q,
  58                                     struct sctp_datamsg *msg)
  59 {
  60 }
  61
  62 static struct sctp_chunk *sctp_sched_fcfs_dequeue(struct sctp_outq *q)
  63 {
  64         struct sctp_stream *stream = &q->asoc->stream;
  65         struct sctp_chunk *ch = NULL;
  66         struct list_head *entry;
  67
  68         if (list_empty(&q->out_chunk_list))
  69                 goto out;
  70
  71         if (stream->out_curr) {
  72                 ch = list_entry(stream->out_curr->ext->outq.next,
  73                                 struct sctp_chunk, stream_list);
  74         } else {
  75                 entry = q->out_chunk_list.next;
  76                 ch = list_entry(entry, struct sctp_chunk, list);
  77         }
  78
  79         sctp_sched_dequeue_common(q, ch);
  80
  81 out:
  82         return ch;
  83 }
  84
  85 static void sctp_sched_fcfs_dequeue_done(struct sctp_outq *q,
  86                                          struct sctp_chunk *chunk)
  87 {
  88 }
  89
  90 static void sctp_sched_fcfs_sched_all(struct sctp_stream *stream)
  91 {
  92 }
  93
  94 static void sctp_sched_fcfs_unsched_all(struct sctp_stream *stream)
  95 {
  96 }
  97
  98 static struct sctp_sched_ops sctp_sched_fcfs = {
  99         .set = sctp_sched_fcfs_set,
 100         .get = sctp_sched_fcfs_get,
 101         .init = sctp_sched_fcfs_init,
 102         .init_sid = sctp_sched_fcfs_init_sid,
 103         .free_sid = sctp_sched_fcfs_free_sid,
 104         .free = sctp_sched_fcfs_free,
 105         .enqueue = sctp_sched_fcfs_enqueue,
 106         .dequeue = sctp_sched_fcfs_dequeue,
 107         .dequeue_done = sctp_sched_fcfs_dequeue_done,
 108         .sched_all = sctp_sched_fcfs_sched_all,
 109         .unsched_all = sctp_sched_fcfs_unsched_all,
 110 };
 111
 112 static void sctp_sched_ops_fcfs_init(void)
 113 {
 114         sctp_sched_ops_register(SCTP_SS_FCFS, &sctp_sched_fcfs);
 115 }
 116
 117 /* API to other parts of the stack */
 118
 119 static struct sctp_sched_ops *sctp_sched_ops[SCTP_SS_MAX + 1];
 120
 121 void sctp_sched_ops_register(enum sctp_sched_type sched,
 122                              struct sctp_sched_ops *sched_ops)
 123 {
 124         sctp_sched_ops[sched] = sched_ops;
 125 }
 126
 127 void sctp_sched_ops_init(void)
 128 {
 129         sctp_sched_ops_fcfs_init();
 130         sctp_sched_ops_prio_init();
 131         sctp_sched_ops_rr_init();
 132 }
 133
 134 int sctp_sched_set_sched(struct sctp_association *asoc,
 135                          enum sctp_sched_type sched)
 136 {
 137         struct sctp_sched_ops *n = sctp_sched_ops[sched];
 138         struct sctp_sched_ops *old = asoc->outqueue.sched;
 139         struct sctp_datamsg *msg = NULL;
 140         struct sctp_chunk *ch;
 141         int i, ret = 0;
 142
 143         if (old == n)
 144                 return ret;
 145
 146         if (sched > SCTP_SS_MAX)
 147                 return -EINVAL;
 148
 149         if (old) {
 150                 old->free(&asoc->stream);
 151
 152                 /* Give the next scheduler a clean slate. */
 153                 for (i = 0; i < asoc->stream.outcnt; i++) {
 154                         struct sctp_stream_out_ext *ext = SCTP_SO(&asoc->stream, i)->ext;
 155
 156                         if (!ext)
 157                                 continue;
 158                         memset_after(ext, 0, outq);
 159                 }
 160         }
 161
 162         asoc->outqueue.sched = n;
 163         n->init(&asoc->stream);
 164         for (i = 0; i < asoc->stream.outcnt; i++) {
 165                 if (!SCTP_SO(&asoc->stream, i)->ext)
 166                         continue;
 167
 168                 ret = n->init_sid(&asoc->stream, i, GFP_ATOMIC);
 169                 if (ret)
 170                         goto err;
 171         }
 172
 173         /* We have to requeue all chunks already queued. */
 174         list_for_each_entry(ch, &asoc->outqueue.out_chunk_list, list) {
 175                 if (ch->msg == msg)
 176                         continue;
 177                 msg = ch->msg;
 178                 n->enqueue(&asoc->outqueue, msg);
 179         }
 180
 181         return ret;
 182
 183 err:
 184         n->free(&asoc->stream);
 185         asoc->outqueue.sched = &sctp_sched_fcfs; /* Always safe */
 186
 187         return ret;
 188 }
 189
 190 int sctp_sched_get_sched(struct sctp_association *asoc)
 191 {
 192         int i;
 193
 194         for (i = 0; i <= SCTP_SS_MAX; i++)
 195                 if (asoc->outqueue.sched == sctp_sched_ops[i])
 196                         return i;
 197
 198         return 0;
 199 }
 200
 201 int sctp_sched_set_value(struct sctp_association *asoc, __u16 sid,
 202                          __u16 value, gfp_t gfp)
 203 {
 204         if (sid >= asoc->stream.outcnt)
 205                 return -EINVAL;
 206
 207         if (!SCTP_SO(&asoc->stream, sid)->ext) {
 208                 int ret;
 209
 210                 ret = sctp_stream_init_ext(&asoc->stream, sid);
 211                 if (ret)
 212                         return ret;
 213         }
 214
 215         return asoc->outqueue.sched->set(&asoc->stream, sid, value, gfp);
 216 }
 217
 218 int sctp_sched_get_value(struct sctp_association *asoc, __u16 sid,
 219                          __u16 *value)
 220 {
 221         if (sid >= asoc->stream.outcnt)
 222                 return -EINVAL;
 223
 224         if (!SCTP_SO(&asoc->stream, sid)->ext)
 225                 return 0;
 226
 227         return asoc->outqueue.sched->get(&asoc->stream, sid, value);
 228 }
 229
 230 void sctp_sched_dequeue_done(struct sctp_outq *q, struct sctp_chunk *ch)
 231 {
 232         if (!list_is_last(&ch->frag_list, &ch->msg->chunks) &&
 233             !q->asoc->peer.intl_capable) {
 234                 struct sctp_stream_out *sout;
 235                 __u16 sid;
 236
 237                 /* datamsg is not finish, so save it as current one,
 238                  * in case application switch scheduler or a higher
 239                  * priority stream comes in.
 240                  */
 241                 sid = sctp_chunk_stream_no(ch);
 242                 sout = SCTP_SO(&q->asoc->stream, sid);
 243                 q->asoc->stream.out_curr = sout;
 244                 return;
 245         }
 246
 247         q->asoc->stream.out_curr = NULL;
 248         q->sched->dequeue_done(q, ch);
 249 }
 250
 251 /* Auxiliary functions for the schedulers */
 252 void sctp_sched_dequeue_common(struct sctp_outq *q, struct sctp_chunk *ch)
 253 {
 254         list_del_init(&ch->list);
 255         list_del_init(&ch->stream_list);
 256         q->out_qlen -= ch->skb->len;
 257 }
 258
 259 int sctp_sched_init_sid(struct sctp_stream *stream, __u16 sid, gfp_t gfp)
 260 {
 261         struct sctp_sched_ops *sched = sctp_sched_ops_from_stream(stream);
 262         struct sctp_stream_out_ext *ext = SCTP_SO(stream, sid)->ext;
 263
 264         INIT_LIST_HEAD(&ext->outq);
 265         return sched->init_sid(stream, sid, gfp);
 266 }
 267
 268 struct sctp_sched_ops *sctp_sched_ops_from_stream(struct sctp_stream *stream)
 269 {
 270         struct sctp_association *asoc;
 271
 272         asoc = container_of(stream, struct sctp_association, stream);
 273
 274         return asoc->outqueue.sched;
 275 }