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 "qemu/osdep.h"
  25 #include "net/queue.h"
  26 #include "qemu/queue.h"
  27 #include "net/net.h"
  28
  29 /* The delivery handler may only return zero if it will call
  30  * qemu_net_queue_flush() when it determines that it is once again able
  31  * to deliver packets. It must also call qemu_net_queue_purge() in its
  32  * cleanup path.
  33  *
  34  * If a sent callback is provided to send(), the caller must handle a
  35  * zero return from the delivery handler by not sending any more packets
  36  * until we have invoked the callback. Only in that case will we queue
  37  * the packet.
  38  *
  39  * If a sent callback isn't provided, we just drop the packet to avoid
  40  * unbounded queueing.
  41  */
  42
  43 struct NetPacket {
  44     QTAILQ_ENTRY(NetPacket) entry;
  45     NetClientState *sender;
  46     unsigned flags;
  47     int size;
  48     NetPacketSent *sent_cb;
  49     uint8_t data[];
  50 };
  51
  52 struct NetQueue {
  53     void *opaque;
  54     uint32_t nq_maxlen;
  55     uint32_t nq_count;
  56     NetQueueDeliverFunc *deliver;
  57
  58     QTAILQ_HEAD(, NetPacket) packets;
  59
  60     unsigned delivering : 1;
  61 };
  62
  63 NetQueue *qemu_new_net_queue(NetQueueDeliverFunc *deliver, void *opaque)
  64 {
  65     NetQueue *queue;
  66
  67     queue = g_new0(NetQueue, 1);
  68
  69     queue->opaque = opaque;
  70     queue->nq_maxlen = 10000;
  71     queue->nq_count = 0;
  72     queue->deliver = deliver;
  73
  74     QTAILQ_INIT(&queue->packets);
  75
  76     queue->delivering = 0;
  77
  78     return queue;
  79 }
  80
  81 void qemu_del_net_queue(NetQueue *queue)
  82 {
  83     NetPacket *packet, *next;
  84
  85     QTAILQ_FOREACH_SAFE(packet, &queue->packets, entry, next) {
  86         QTAILQ_REMOVE(&queue->packets, packet, entry);
  87         g_free(packet);
  88     }
  89
  90     g_free(queue);
  91 }
  92
  93 static void qemu_net_queue_append(NetQueue *queue,
  94                                   NetClientState *sender,
  95                                   unsigned flags,
  96                                   const uint8_t *buf,
  97                                   size_t size,
  98                                   NetPacketSent *sent_cb)
  99 {
 100     NetPacket *packet;
 101
 102     if (queue->nq_count >= queue->nq_maxlen && !sent_cb) {
 103         return; /* drop if queue full and no callback */
 104     }
 105     packet = g_malloc(sizeof(NetPacket) + size);
 106     packet->sender = sender;
 107     packet->flags = flags;
 108     packet->size = size;
 109     packet->sent_cb = sent_cb;
 110     memcpy(packet->data, buf, size);
 111
 112     queue->nq_count++;
 113     QTAILQ_INSERT_TAIL(&queue->packets, packet, entry);
 114 }
 115
 116 void qemu_net_queue_append_iov(NetQueue *queue,
 117                                NetClientState *sender,
 118                                unsigned flags,
 119                                const struct iovec *iov,
 120                                int iovcnt,
 121                                NetPacketSent *sent_cb)
 122 {
 123     NetPacket *packet;
 124     size_t max_len = 0;
 125     int i;
 126
 127     if (queue->nq_count >= queue->nq_maxlen && !sent_cb) {
 128         return; /* drop if queue full and no callback */
 129     }
 130     for (i = 0; i < iovcnt; i++) {
 131         max_len += iov[i].iov_len;
 132     }
 133
 134     packet = g_malloc(sizeof(NetPacket) + max_len);
 135     packet->sender = sender;
 136     packet->sent_cb = sent_cb;
 137     packet->flags = flags;
 138     packet->size = 0;
 139
 140     for (i = 0; i < iovcnt; i++) {
 141         size_t len = iov[i].iov_len;
 142
 143         memcpy(packet->data + packet->size, iov[i].iov_base, len);
 144         packet->size += len;
 145     }
 146
 147     queue->nq_count++;
 148     QTAILQ_INSERT_TAIL(&queue->packets, packet, entry);
 149 }
 150
 151 static ssize_t qemu_net_queue_deliver(NetQueue *queue,
 152                                       NetClientState *sender,
 153                                       unsigned flags,
 154                                       const uint8_t *data,
 155                                       size_t size)
 156 {
 157     ssize_t ret = -1;
 158     struct iovec iov = {
 159         .iov_base = (void *)data,
 160         .iov_len = size
 161     };
 162
 163     queue->delivering = 1;
 164     ret = queue->deliver(sender, flags, &iov, 1, queue->opaque);
 165     queue->delivering = 0;
 166
 167     return ret;
 168 }
 169
 170 static ssize_t qemu_net_queue_deliver_iov(NetQueue *queue,
 171                                           NetClientState *sender,
 172                                           unsigned flags,
 173                                           const struct iovec *iov,
 174                                           int iovcnt)
 175 {
 176     ssize_t ret = -1;
 177
 178     queue->delivering = 1;
 179     ret = queue->deliver(sender, flags, iov, iovcnt, queue->opaque);
 180     queue->delivering = 0;
 181
 182     return ret;
 183 }
 184
 185 ssize_t qemu_net_queue_send(NetQueue *queue,
 186                             NetClientState *sender,
 187                             unsigned flags,
 188                             const uint8_t *data,
 189                             size_t size,
 190                             NetPacketSent *sent_cb)
 191 {
 192     ssize_t ret;
 193
 194     if (queue->delivering || !qemu_can_send_packet(sender)) {
 195         qemu_net_queue_append(queue, sender, flags, data, size, sent_cb);
 196         return 0;
 197     }
 198
 199     ret = qemu_net_queue_deliver(queue, sender, flags, data, size);
 200     if (ret == 0) {
 201         qemu_net_queue_append(queue, sender, flags, data, size, sent_cb);
 202         return 0;
 203     }
 204
 205     qemu_net_queue_flush(queue);
 206
 207     return ret;
 208 }
 209
 210 ssize_t qemu_net_queue_send_iov(NetQueue *queue,
 211                                 NetClientState *sender,
 212                                 unsigned flags,
 213                                 const struct iovec *iov,
 214                                 int iovcnt,
 215                                 NetPacketSent *sent_cb)
 216 {
 217     ssize_t ret;
 218
 219     if (queue->delivering || !qemu_can_send_packet(sender)) {
 220         qemu_net_queue_append_iov(queue, sender, flags, iov, iovcnt, sent_cb);
 221         return 0;
 222     }
 223
 224     ret = qemu_net_queue_deliver_iov(queue, sender, flags, iov, iovcnt);
 225     if (ret == 0) {
 226         qemu_net_queue_append_iov(queue, sender, flags, iov, iovcnt, sent_cb);
 227         return 0;
 228     }
 229
 230     qemu_net_queue_flush(queue);
 231
 232     return ret;
 233 }
 234
 235 void qemu_net_queue_purge(NetQueue *queue, NetClientState *from)
 236 {
 237     NetPacket *packet, *next;
 238
 239     QTAILQ_FOREACH_SAFE(packet, &queue->packets, entry, next) {
 240         if (packet->sender == from) {
 241             QTAILQ_REMOVE(&queue->packets, packet, entry);
 242             queue->nq_count--;
 243             if (packet->sent_cb) {
 244                 packet->sent_cb(packet->sender, 0);
 245             }
 246             g_free(packet);
 247         }
 248     }
 249 }
 250
 251 bool qemu_net_queue_flush(NetQueue *queue)
 252 {
 253     if (queue->delivering)
 254         return false;
 255
 256     while (!QTAILQ_EMPTY(&queue->packets)) {
 257         NetPacket *packet;
 258         int ret;
 259
 260         packet = QTAILQ_FIRST(&queue->packets);
 261         QTAILQ_REMOVE(&queue->packets, packet, entry);
 262         queue->nq_count--;
 263
 264         ret = qemu_net_queue_deliver(queue,
 265                                      packet->sender,
 266                                      packet->flags,
 267                                      packet->data,
 268                                      packet->size);
 269         if (ret == 0) {
 270             queue->nq_count++;
 271             QTAILQ_INSERT_HEAD(&queue->packets, packet, entry);
 272             return false;
 273         }
 274
 275         if (packet->sent_cb) {
 276             packet->sent_cb(packet->sender, ret);
 277         }
 278
 279         g_free(packet);
 280     }
 281     return true;
 282 }