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.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
  54     QTAILQ_HEAD(packets, NetPacket) packets;
  55
  56     unsigned delivering : 1;
  57 };
  58
  59 NetQueue *qemu_new_net_queue(void *opaque)
  60 {
  61     NetQueue *queue;
  62
  63     queue = g_malloc0(sizeof(NetQueue));
  64
  65     queue->opaque = opaque;
  66
  67     QTAILQ_INIT(&queue->packets);
  68
  69     queue->delivering = 0;
  70
  71     return queue;
  72 }
  73
  74 void qemu_del_net_queue(NetQueue *queue)
  75 {
  76     NetPacket *packet, *next;
  77
  78     QTAILQ_FOREACH_SAFE(packet, &queue->packets, entry, next) {
  79         QTAILQ_REMOVE(&queue->packets, packet, entry);
  80         g_free(packet);
  81     }
  82
  83     g_free(queue);
  84 }
  85
  86 static void qemu_net_queue_append(NetQueue *queue,
  87                                   NetClientState *sender,
  88                                   unsigned flags,
  89                                   const uint8_t *buf,
  90                                   size_t size,
  91                                   NetPacketSent *sent_cb)
  92 {
  93     NetPacket *packet;
  94
  95     packet = g_malloc(sizeof(NetPacket) + size);
  96     packet->sender = sender;
  97     packet->flags = flags;
  98     packet->size = size;
  99     packet->sent_cb = sent_cb;
 100     memcpy(packet->data, buf, size);
 101
 102     QTAILQ_INSERT_TAIL(&queue->packets, packet, entry);
 103 }
 104
 105 static void qemu_net_queue_append_iov(NetQueue *queue,
 106                                       NetClientState *sender,
 107                                       unsigned flags,
 108                                       const struct iovec *iov,
 109                                       int iovcnt,
 110                                       NetPacketSent *sent_cb)
 111 {
 112     NetPacket *packet;
 113     size_t max_len = 0;
 114     int i;
 115
 116     for (i = 0; i < iovcnt; i++) {
 117         max_len += iov[i].iov_len;
 118     }
 119
 120     packet = g_malloc(sizeof(NetPacket) + max_len);
 121     packet->sender = sender;
 122     packet->sent_cb = sent_cb;
 123     packet->flags = flags;
 124     packet->size = 0;
 125
 126     for (i = 0; i < iovcnt; i++) {
 127         size_t len = iov[i].iov_len;
 128
 129         memcpy(packet->data + packet->size, iov[i].iov_base, len);
 130         packet->size += len;
 131     }
 132
 133     QTAILQ_INSERT_TAIL(&queue->packets, packet, entry);
 134 }
 135
 136 static ssize_t qemu_net_queue_deliver(NetQueue *queue,
 137                                       NetClientState *sender,
 138                                       unsigned flags,
 139                                       const uint8_t *data,
 140                                       size_t size)
 141 {
 142     ssize_t ret = -1;
 143
 144     queue->delivering = 1;
 145     ret = qemu_deliver_packet(sender, flags, data, size, queue->opaque);
 146     queue->delivering = 0;
 147
 148     return ret;
 149 }
 150
 151 static ssize_t qemu_net_queue_deliver_iov(NetQueue *queue,
 152                                           NetClientState *sender,
 153                                           unsigned flags,
 154                                           const struct iovec *iov,
 155                                           int iovcnt)
 156 {
 157     ssize_t ret = -1;
 158
 159     queue->delivering = 1;
 160     ret = qemu_deliver_packet_iov(sender, flags, iov, iovcnt, queue->opaque);
 161     queue->delivering = 0;
 162
 163     return ret;
 164 }
 165
 166 ssize_t qemu_net_queue_send(NetQueue *queue,
 167                             NetClientState *sender,
 168                             unsigned flags,
 169                             const uint8_t *data,
 170                             size_t size,
 171                             NetPacketSent *sent_cb)
 172 {
 173     ssize_t ret;
 174
 175     if (queue->delivering || !qemu_can_send_packet(sender)) {
 176         qemu_net_queue_append(queue, sender, flags, data, size, sent_cb);
 177         return 0;
 178     }
 179
 180     ret = qemu_net_queue_deliver(queue, sender, flags, data, size);
 181     if (ret == 0) {
 182         qemu_net_queue_append(queue, sender, flags, data, size, sent_cb);
 183         return 0;
 184     }
 185
 186     qemu_net_queue_flush(queue);
 187
 188     return ret;
 189 }
 190
 191 ssize_t qemu_net_queue_send_iov(NetQueue *queue,
 192                                 NetClientState *sender,
 193                                 unsigned flags,
 194                                 const struct iovec *iov,
 195                                 int iovcnt,
 196                                 NetPacketSent *sent_cb)
 197 {
 198     ssize_t ret;
 199
 200     if (queue->delivering || !qemu_can_send_packet(sender)) {
 201         qemu_net_queue_append_iov(queue, sender, flags, iov, iovcnt, sent_cb);
 202         return 0;
 203     }
 204
 205     ret = qemu_net_queue_deliver_iov(queue, sender, flags, iov, iovcnt);
 206     if (ret == 0) {
 207         qemu_net_queue_append_iov(queue, sender, flags, iov, iovcnt, sent_cb);
 208         return 0;
 209     }
 210
 211     qemu_net_queue_flush(queue);
 212
 213     return ret;
 214 }
 215
 216 void qemu_net_queue_purge(NetQueue *queue, NetClientState *from)
 217 {
 218     NetPacket *packet, *next;
 219
 220     QTAILQ_FOREACH_SAFE(packet, &queue->packets, entry, next) {
 221         if (packet->sender == from) {
 222             QTAILQ_REMOVE(&queue->packets, packet, entry);
 223             g_free(packet);
 224         }
 225     }
 226 }
 227
 228 bool qemu_net_queue_flush(NetQueue *queue)
 229 {
 230     while (!QTAILQ_EMPTY(&queue->packets)) {
 231         NetPacket *packet;
 232         int ret;
 233
 234         packet = QTAILQ_FIRST(&queue->packets);
 235         QTAILQ_REMOVE(&queue->packets, packet, entry);
 236
 237         ret = qemu_net_queue_deliver(queue,
 238                                      packet->sender,
 239                                      packet->flags,
 240                                      packet->data,
 241                                      packet->size);
 242         if (ret == 0) {
 243             QTAILQ_INSERT_HEAD(&queue->packets, packet, entry);
 244             return false;
 245         }
 246
 247         if (packet->sent_cb) {
 248             packet->sent_cb(packet->sender, ret);
 249         }
 250
 251         g_free(packet);
 252     }
 253     return true;
 254 }