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_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 }
 128
 129 static void sctp_sched_free_sched(struct sctp_stream *stream)
 130 {
 131         struct sctp_sched_ops *sched = sctp_sched_ops_from_stream(stream);
 132         struct sctp_stream_out_ext *soute;
 133         int i;
 134
 135         sched->unsched_all(stream);
 136         for (i = 0; i < stream->outcnt; i++) {
 137                 soute = SCTP_SO(stream, i)->ext;
 138                 if (!soute)
 139                         continue;
 140                 sched->free_sid(stream, i);
 141                 /* Give the next scheduler a clean slate. */
 142                 memset_after(soute, 0, outq);
 143         }
 144 }
 145
 146 int sctp_sched_set_sched(struct sctp_association *asoc,
 147                          enum sctp_sched_type sched)
 148 {
 149         struct sctp_sched_ops *n = sctp_sched_ops[sched];
 150         struct sctp_sched_ops *old = asoc->outqueue.sched;
 151         struct sctp_datamsg *msg = NULL;
 152         struct sctp_chunk *ch;
 153         int i, ret = 0;
 154
 155         if (old == n)
 156                 return ret;
 157
 158         if (sched > SCTP_SS_MAX)
 159                 return -EINVAL;
 160
 161         if (old)
 162                 sctp_sched_free_sched(&asoc->stream);
 163
 164         asoc->outqueue.sched = n;
 165         n->init(&asoc->stream);
 166         for (i = 0; i < asoc->stream.outcnt; i++) {
 167                 if (!SCTP_SO(&asoc->stream, i)->ext)
 168                         continue;
 169
 170                 ret = n->init_sid(&asoc->stream, i, GFP_ATOMIC);
 171                 if (ret)
 172                         goto err;
 173         }
 174
 175         /* We have to requeue all chunks already queued. */
 176         list_for_each_entry(ch, &asoc->outqueue.out_chunk_list, list) {
 177                 if (ch->msg == msg)
 178                         continue;
 179                 msg = ch->msg;
 180                 n->enqueue(&asoc->outqueue, msg);
 181         }
 182
 183         return ret;
 184
 185 err:
 186         sctp_sched_free_sched(&asoc->stream);
 187         asoc->outqueue.sched = &sctp_sched_fcfs; /* Always safe */
 188
 189         return ret;
 190 }
 191
 192 int sctp_sched_get_sched(struct sctp_association *asoc)
 193 {
 194         int i;
 195
 196         for (i = 0; i <= SCTP_SS_MAX; i++)
 197                 if (asoc->outqueue.sched == sctp_sched_ops[i])
 198                         return i;
 199
 200         return 0;
 201 }
 202
 203 int sctp_sched_set_value(struct sctp_association *asoc, __u16 sid,
 204                          __u16 value, gfp_t gfp)
 205 {
 206         if (sid >= asoc->stream.outcnt)
 207                 return -EINVAL;
 208
 209         if (!SCTP_SO(&asoc->stream, sid)->ext) {
 210                 int ret;
 211
 212                 ret = sctp_stream_init_ext(&asoc->stream, sid);
 213                 if (ret)
 214                         return ret;
 215         }
 216
 217         return asoc->outqueue.sched->set(&asoc->stream, sid, value, gfp);
 218 }
 219
 220 int sctp_sched_get_value(struct sctp_association *asoc, __u16 sid,
 221                          __u16 *value)
 222 {
 223         if (sid >= asoc->stream.outcnt)
 224                 return -EINVAL;
 225
 226         if (!SCTP_SO(&asoc->stream, sid)->ext)
 227                 return 0;
 228
 229         return asoc->outqueue.sched->get(&asoc->stream, sid, value);
 230 }
 231
 232 void sctp_sched_dequeue_done(struct sctp_outq *q, struct sctp_chunk *ch)
 233 {
 234         if (!list_is_last(&ch->frag_list, &ch->msg->chunks) &&
 235             !q->asoc->peer.intl_capable) {
 236                 struct sctp_stream_out *sout;
 237                 __u16 sid;
 238
 239                 /* datamsg is not finish, so save it as current one,
 240                  * in case application switch scheduler or a higher
 241                  * priority stream comes in.
 242                  */
 243                 sid = sctp_chunk_stream_no(ch);
 244                 sout = SCTP_SO(&q->asoc->stream, sid);
 245                 q->asoc->stream.out_curr = sout;
 246                 return;
 247         }
 248
 249         q->asoc->stream.out_curr = NULL;
 250         q->sched->dequeue_done(q, ch);
 251 }
 252
 253 /* Auxiliary functions for the schedulers */
 254 void sctp_sched_dequeue_common(struct sctp_outq *q, struct sctp_chunk *ch)
 255 {
 256         list_del_init(&ch->list);
 257         list_del_init(&ch->stream_list);
 258         q->out_qlen -= ch->skb->len;
 259 }
 260
 261 int sctp_sched_init_sid(struct sctp_stream *stream, __u16 sid, gfp_t gfp)
 262 {
 263         struct sctp_sched_ops *sched = sctp_sched_ops_from_stream(stream);
 264         struct sctp_stream_out_ext *ext = SCTP_SO(stream, sid)->ext;
 265
 266         INIT_LIST_HEAD(&ext->outq);
 267         return sched->init_sid(stream, sid, gfp);
 268 }
 269
 270 struct sctp_sched_ops *sctp_sched_ops_from_stream(struct sctp_stream *stream)
 271 {
 272         struct sctp_association *asoc;
 273
 274         asoc = container_of(stream, struct sctp_association, stream);
 275
 276         return asoc->outqueue.sched;
 277 }