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 #include "net/net.h"
  27
  28 /* The delivery handler may only return zero if it will call
  29  * qemu_net_queue_flush() when it determines that it is once again able
  30  * to deliver packets. It must also call qemu_net_queue_purge() in its
  31  * cleanup path.
  32  *
  33  * If a sent callback is provided to send(), the caller must handle a
  34  * zero return from the delivery handler by not sending any more packets
  35  * until we have invoked the callback. Only in that case will we queue
  36  * the packet.
  37  *
  38  * If a sent callback isn't provided, we just drop the packet to avoid
  39  * unbounded queueing.
  40  */
  41
  42 struct NetPacket {
  43     QTAILQ_ENTRY(NetPacket) entry;
  44     NetClientState *sender;
  45     unsigned flags;
  46     int size;
  47     NetPacketSent *sent_cb;
  48     uint8_t data[0];
  49 };
  50
  51 struct NetQueue {
  52     void *opaque;
  53     uint32_t nq_maxlen;
  54     uint32_t nq_count;
  55
  56     QTAILQ_HEAD(packets, NetPacket) packets;
  57
  58     unsigned delivering : 1;
  59 };
  60
  61 NetQueue *qemu_new_net_queue(void *opaque)
  62 {
  63     NetQueue *queue;
  64
  65     queue = g_malloc0(sizeof(NetQueue));
  66
  67     queue->opaque = opaque;
  68     queue->nq_maxlen = 10000;
  69     queue->nq_count = 0;
  70
  71     QTAILQ_INIT(&queue->packets);
  72
  73     queue->delivering = 0;
  74
  75     return queue;
  76 }
  77
  78 void qemu_del_net_queue(NetQueue *queue)
  79 {
  80     NetPacket *packet, *next;
  81
  82     QTAILQ_FOREACH_SAFE(packet, &queue->packets, entry, next) {
  83         QTAILQ_REMOVE(&queue->packets, packet, entry);
  84         g_free(packet);
  85     }
  86
  87     g_free(queue);
  88 }
  89
  90 static void qemu_net_queue_append(NetQueue *queue,
  91                                   NetClientState *sender,
  92                                   unsigned flags,
  93                                   const uint8_t *buf,
  94                                   size_t size,
  95                                   NetPacketSent *sent_cb)
  96 {
  97     NetPacket *packet;
  98
  99     if (queue->nq_count >= queue->nq_maxlen && !sent_cb) {
 100         return; /* drop if queue full and no callback */
 101     }
 102     packet = g_malloc(sizeof(NetPacket) + size);
 103     packet->sender = sender;
 104     packet->flags = flags;
 105     packet->size = size;
 106     packet->sent_cb = sent_cb;
 107     memcpy(packet->data, buf, size);
 108
 109     queue->nq_count++;
 110     QTAILQ_INSERT_TAIL(&queue->packets, packet, entry);
 111 }
 112
 113 static void qemu_net_queue_append_iov(NetQueue *queue,
 114                                       NetClientState *sender,
 115                                       unsigned flags,
 116                                       const struct iovec *iov,
 117                                       int iovcnt,
 118                                       NetPacketSent *sent_cb)
 119 {
 120     NetPacket *packet;
 121     size_t max_len = 0;
 122     int i;
 123
 124     if (queue->nq_count >= queue->nq_maxlen && !sent_cb) {
 125         return; /* drop if queue full and no callback */
 126     }
 127     for (i = 0; i < iovcnt; i++) {
 128         max_len += iov[i].iov_len;
 129     }
 130
 131     packet = g_malloc(sizeof(NetPacket) + max_len);
 132     packet->sender = sender;
 133     packet->sent_cb = sent_cb;
 134     packet->flags = flags;
 135     packet->size = 0;
 136
 137     for (i = 0; i < iovcnt; i++) {
 138         size_t len = iov[i].iov_len;
 139
 140         memcpy(packet->data + packet->size, iov[i].iov_base, len);
 141         packet->size += len;
 142     }
 143
 144     queue->nq_count++;
 145     QTAILQ_INSERT_TAIL(&queue->packets, packet, entry);
 146 }
 147
 148 static ssize_t qemu_net_queue_deliver(NetQueue *queue,
 149                                       NetClientState *sender,
 150                                       unsigned flags,
 151                                       const uint8_t *data,
 152                                       size_t size)
 153 {
 154     ssize_t ret = -1;
 155
 156     queue->delivering = 1;
 157     ret = qemu_deliver_packet(sender, flags, data, size, queue->opaque);
 158     queue->delivering = 0;
 159
 160     return ret;
 161 }
 162
 163 static ssize_t qemu_net_queue_deliver_iov(NetQueue *queue,
 164                                           NetClientState *sender,
 165                                           unsigned flags,
 166                                           const struct iovec *iov,
 167                                           int iovcnt)
 168 {
 169     ssize_t ret = -1;
 170
 171     queue->delivering = 1;
 172     ret = qemu_deliver_packet_iov(sender, flags, iov, iovcnt, queue->opaque);
 173     queue->delivering = 0;
 174
 175     return ret;
 176 }
 177
 178 ssize_t qemu_net_queue_send(NetQueue *queue,
 179                             NetClientState *sender,
 180                             unsigned flags,
 181                             const uint8_t *data,
 182                             size_t size,
 183                             NetPacketSent *sent_cb)
 184 {
 185     ssize_t ret;
 186
 187     if (queue->delivering || !qemu_can_send_packet(sender)) {
 188         qemu_net_queue_append(queue, sender, flags, data, size, sent_cb);
 189         return 0;
 190     }
 191
 192     ret = qemu_net_queue_deliver(queue, sender, flags, data, size);
 193     if (ret == 0) {
 194         qemu_net_queue_append(queue, sender, flags, data, size, sent_cb);
 195         return 0;
 196     }
 197
 198     qemu_net_queue_flush(queue);
 199
 200     return ret;
 201 }
 202
 203 ssize_t qemu_net_queue_send_iov(NetQueue *queue,
 204                                 NetClientState *sender,
 205                                 unsigned flags,
 206                                 const struct iovec *iov,
 207                                 int iovcnt,
 208                                 NetPacketSent *sent_cb)
 209 {
 210     ssize_t ret;
 211
 212     if (queue->delivering || !qemu_can_send_packet(sender)) {
 213         qemu_net_queue_append_iov(queue, sender, flags, iov, iovcnt, sent_cb);
 214         return 0;
 215     }
 216
 217     ret = qemu_net_queue_deliver_iov(queue, sender, flags, iov, iovcnt);
 218     if (ret == 0) {
 219         qemu_net_queue_append_iov(queue, sender, flags, iov, iovcnt, sent_cb);
 220         return 0;
 221     }
 222
 223     qemu_net_queue_flush(queue);
 224
 225     return ret;
 226 }
 227
 228 void qemu_net_queue_purge(NetQueue *queue, NetClientState *from)
 229 {
 230     NetPacket *packet, *next;
 231
 232     QTAILQ_FOREACH_SAFE(packet, &queue->packets, entry, next) {
 233         if (packet->sender == from) {
 234             QTAILQ_REMOVE(&queue->packets, packet, entry);
 235             queue->nq_count--;
 236             g_free(packet);
 237         }
 238     }
 239 }
 240
 241 bool qemu_net_queue_flush(NetQueue *queue)
 242 {
 243     while (!QTAILQ_EMPTY(&queue->packets)) {
 244         NetPacket *packet;
 245         int ret;
 246
 247         packet = QTAILQ_FIRST(&queue->packets);
 248         QTAILQ_REMOVE(&queue->packets, packet, entry);
 249         queue->nq_count--;
 250
 251         ret = qemu_net_queue_deliver(queue,
 252                                      packet->sender,
 253                                      packet->flags,
 254                                      packet->data,
 255                                      packet->size);
 256         if (ret == 0) {
 257             queue->nq_count++;
 258             QTAILQ_INSERT_HEAD(&queue->packets, packet, entry);
 259             return false;
 260         }
 261
 262         if (packet->sent_cb) {
 263             packet->sent_cb(packet->sender, ret);
 264         }
 265
 266         g_free(packet);
 267     }
 268     return true;
 269 }