net/sctp/stream_sched.c

   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 = SCTP_SO(&asoc->stream, 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 (!SCTP_SO(&asoc->stream, 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 (!SCTP_SO(&asoc->stream, 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 (!SCTP_SO(&asoc->stream, 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 = SCTP_SO(&q->asoc->stream, 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         struct sctp_stream_out_ext *ext = SCTP_SO(stream, sid)->ext;
 276
 277         INIT_LIST_HEAD(&ext->outq);
 278         return sched->init_sid(stream, sid, gfp);
 279 }
 280
 281 struct sctp_sched_ops *sctp_sched_ops_from_stream(struct sctp_stream *stream)
 282 {
 283         struct sctp_association *asoc;
 284
 285         asoc = container_of(stream, struct sctp_association, stream);
 286
 287         return asoc->outqueue.sched;
 288 }