net/queue.c

   1 /*
   2  * Copyright (c) 2003-2008 Fabrice Bellard
   3  * Copyright (c) 2009 Red Hat, Inc.
   4  *
   5  * Permission is hereby granted, free of charge, to any person obtaining a copy
   6  * of this software and associated documentation files (the "Software"), to deal
   7  * in the Software without restriction, including without limitation the rights
   8  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
   9  * copies of the Software, and to permit persons to whom the Software is
  10  * furnished to do so, subject to the following conditions:
  11  *
  12  * The above copyright notice and this permission notice shall be included in
  13  * all copies or substantial portions of the Software.
  14  *
  15  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  16  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  17  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
  18  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  19  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  20  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  21  * THE SOFTWARE.
  22  */
  23
  24 #include "net/queue.h"
  25 #include "qemu-queue.h"
  26
  27 /* The delivery handler may only return zero if it will call
  28  * qemu_net_queue_flush() when it determines that it is once again able
  29  * to deliver packets. It must also call qemu_net_queue_purge() in its
  30  * cleanup path.
  31  *
  32  * If a sent callback is provided to send(), the caller must handle a
  33  * zero return from the delivery handler by not sending any more packets
  34  * until we have invoked the callback. Only in that case will we queue
  35  * the packet.
  36  *
  37  * If a sent callback isn't provided, we just drop the packet to avoid
  38  * unbounded queueing.
  39  */
  40
  41 struct NetPacket {
  42     QTAILQ_ENTRY(NetPacket) entry;
  43     VLANClientState *sender;
  44     unsigned flags;
  45     int size;
  46     NetPacketSent *sent_cb;
  47     uint8_t data[0];
  48 };
  49
  50 struct NetQueue {
  51     NetPacketDeliver *deliver;
  52     NetPacketDeliverIOV *deliver_iov;
  53     void *opaque;
  54
  55     QTAILQ_HEAD(packets, NetPacket) packets;
  56
  57     unsigned delivering : 1;
  58 };
  59
  60 NetQueue *qemu_new_net_queue(NetPacketDeliver *deliver,
  61                              NetPacketDeliverIOV *deliver_iov,
  62                              void *opaque)
  63 {
  64     NetQueue *queue;
  65
  66     queue = qemu_mallocz(sizeof(NetQueue));
  67
  68     queue->deliver = deliver;
  69     queue->deliver_iov = deliver_iov;
  70     queue->opaque = opaque;
  71
  72     QTAILQ_INIT(&queue->packets);
  73
  74     queue->delivering = 0;
  75
  76     return queue;
  77 }
  78
  79 void qemu_del_net_queue(NetQueue *queue)
  80 {
  81     NetPacket *packet, *next;
  82
  83     QTAILQ_FOREACH_SAFE(packet, &queue->packets, entry, next) {
  84         QTAILQ_REMOVE(&queue->packets, packet, entry);
  85         qemu_free(packet);
  86     }
  87
  88     qemu_free(queue);
  89 }
  90
  91 static ssize_t qemu_net_queue_append(NetQueue *queue,
  92                                      VLANClientState *sender,
  93                                      unsigned flags,
  94                                      const uint8_t *buf,
  95                                      size_t size,
  96                                      NetPacketSent *sent_cb)
  97 {
  98     NetPacket *packet;
  99
 100     packet = qemu_malloc(sizeof(NetPacket) + size);
 101     packet->sender = sender;
 102     packet->flags = flags;
 103     packet->size = size;
 104     packet->sent_cb = sent_cb;
 105     memcpy(packet->data, buf, size);
 106
 107     QTAILQ_INSERT_TAIL(&queue->packets, packet, entry);
 108
 109     return size;
 110 }
 111
 112 static ssize_t qemu_net_queue_append_iov(NetQueue *queue,
 113                                          VLANClientState *sender,
 114                                          unsigned flags,
 115                                          const struct iovec *iov,
 116                                          int iovcnt,
 117                                          NetPacketSent *sent_cb)
 118 {
 119     NetPacket *packet;
 120     size_t max_len = 0;
 121     int i;
 122
 123     for (i = 0; i < iovcnt; i++) {
 124         max_len += iov[i].iov_len;
 125     }
 126
 127     packet = qemu_malloc(sizeof(NetPacket) + max_len);
 128     packet->sender = sender;
 129     packet->sent_cb = sent_cb;
 130     packet->flags = flags;
 131     packet->size = 0;
 132
 133     for (i = 0; i < iovcnt; i++) {
 134         size_t len = iov[i].iov_len;
 135
 136         memcpy(packet->data + packet->size, iov[i].iov_base, len);
 137         packet->size += len;
 138     }
 139
 140     QTAILQ_INSERT_TAIL(&queue->packets, packet, entry);
 141
 142     return packet->size;
 143 }
 144
 145 static ssize_t qemu_net_queue_deliver(NetQueue *queue,
 146                                       VLANClientState *sender,
 147                                       unsigned flags,
 148                                       const uint8_t *data,
 149                                       size_t size)
 150 {
 151     ssize_t ret = -1;
 152
 153     queue->delivering = 1;
 154     ret = queue->deliver(sender, flags, data, size, queue->opaque);
 155     queue->delivering = 0;
 156
 157     return ret;
 158 }
 159
 160 static ssize_t qemu_net_queue_deliver_iov(NetQueue *queue,
 161                                           VLANClientState *sender,
 162                                           unsigned flags,
 163                                           const struct iovec *iov,
 164                                           int iovcnt)
 165 {
 166     ssize_t ret = -1;
 167
 168     queue->delivering = 1;
 169     ret = queue->deliver_iov(sender, flags, iov, iovcnt, queue->opaque);
 170     queue->delivering = 0;
 171
 172     return ret;
 173 }
 174
 175 ssize_t qemu_net_queue_send(NetQueue *queue,
 176                             VLANClientState *sender,
 177                             unsigned flags,
 178                             const uint8_t *data,
 179                             size_t size,
 180                             NetPacketSent *sent_cb)
 181 {
 182     ssize_t ret;
 183
 184     if (queue->delivering) {
 185         return qemu_net_queue_append(queue, sender, flags, data, size, NULL);
 186     }
 187
 188     ret = qemu_net_queue_deliver(queue, sender, flags, data, size);
 189     if (ret == 0 && sent_cb != NULL) {
 190         qemu_net_queue_append(queue, sender, flags, data, size, sent_cb);
 191         return 0;
 192     }
 193
 194     qemu_net_queue_flush(queue);
 195
 196     return ret;
 197 }
 198
 199 ssize_t qemu_net_queue_send_iov(NetQueue *queue,
 200                                 VLANClientState *sender,
 201                                 unsigned flags,
 202                                 const struct iovec *iov,
 203                                 int iovcnt,
 204                                 NetPacketSent *sent_cb)
 205 {
 206     ssize_t ret;
 207
 208     if (queue->delivering) {
 209         return qemu_net_queue_append_iov(queue, sender, flags, iov, iovcnt, NULL);
 210     }
 211
 212     ret = qemu_net_queue_deliver_iov(queue, sender, flags, iov, iovcnt);
 213     if (ret == 0 && sent_cb != NULL) {
 214         qemu_net_queue_append_iov(queue, sender, flags, iov, iovcnt, sent_cb);
 215         return 0;
 216     }
 217
 218     qemu_net_queue_flush(queue);
 219
 220     return ret;
 221 }
 222
 223 void qemu_net_queue_purge(NetQueue *queue, VLANClientState *from)
 224 {
 225     NetPacket *packet, *next;
 226
 227     QTAILQ_FOREACH_SAFE(packet, &queue->packets, entry, next) {
 228         if (packet->sender == from) {
 229             QTAILQ_REMOVE(&queue->packets, packet, entry);
 230             qemu_free(packet);
 231         }
 232     }
 233 }
 234
 235 void qemu_net_queue_flush(NetQueue *queue)
 236 {
 237     while (!QTAILQ_EMPTY(&queue->packets)) {
 238         NetPacket *packet;
 239         int ret;
 240
 241         packet = QTAILQ_FIRST(&queue->packets);
 242         QTAILQ_REMOVE(&queue->packets, packet, entry);
 243
 244         ret = qemu_net_queue_deliver(queue,
 245                                      packet->sender,
 246                                      packet->flags,
 247                                      packet->data,
 248                                      packet->size);
 249         if (ret == 0 && packet->sent_cb != NULL) {
 250             QTAILQ_INSERT_HEAD(&queue->packets, packet, entry);
 251             break;
 252         }
 253
 254         if (packet->sent_cb) {
 255             packet->sent_cb(packet->sender, ret);
 256         }
 257
 258         qemu_free(packet);
 259     }
 260 }