diff --git a/net-queue.c b/net-queue.c
new file mode 100644
index 0000000..75457f0
--- /dev/null
+++ b/net-queue.c
@@ -0,0 +1,250 @@
+/*
+ * Copyright (c) 2003-2008 Fabrice Bellard
+ * Copyright (c) 2009 Red Hat, Inc.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+#include "net-queue.h"
+#include "qemu-queue.h"
+
+/* The delivery handler may only return zero if it will call
+ * qemu_net_queue_flush() when it determines that it is once again able
+ * to deliver packets. It must also call qemu_net_queue_purge() in its
+ * cleanup path.
+ *
+ * If a sent callback is provided to send(), the caller must handle a
+ * zero return from the delivery handler by not sending any more packets
+ * until we have invoked the callback. Only in that case will we queue
+ * the packet.
+ *
+ * If a sent callback isn't provided, we just drop the packet to avoid
+ * unbounded queueing.
+ */
+
+struct NetPacket {
+    QTAILQ_ENTRY(NetPacket) entry;
+    VLANClientState *sender;
+    int size;
+    NetPacketSent *sent_cb;
+    uint8_t data[0];
+};
+
+struct NetQueue {
+    NetPacketDeliver *deliver;
+    NetPacketDeliverIOV *deliver_iov;
+    void *opaque;
+
+    QTAILQ_HEAD(packets, NetPacket) packets;
+
+    unsigned delivering : 1;
+};
+
+NetQueue *qemu_new_net_queue(NetPacketDeliver *deliver,
+                             NetPacketDeliverIOV *deliver_iov,
+                             void *opaque)
+{
+    NetQueue *queue;
+
+    queue = qemu_mallocz(sizeof(NetQueue));
+
+    queue->deliver = deliver;
+    queue->deliver_iov = deliver_iov;
+    queue->opaque = opaque;
+
+    QTAILQ_INIT(&queue->packets);
+
+    queue->delivering = 0;
+
+    return queue;
+}
+
+void qemu_del_net_queue(NetQueue *queue)
+{
+    NetPacket *packet, *next;
+
+    QTAILQ_FOREACH_SAFE(packet, &queue->packets, entry, next) {
+        QTAILQ_REMOVE(&queue->packets, packet, entry);
+        qemu_free(packet);
+    }
+
+    qemu_free(queue);
+}
+
+static ssize_t qemu_net_queue_append(NetQueue *queue,
+                                     VLANClientState *sender,
+                                     const uint8_t *buf,
+                                     size_t size,
+                                     NetPacketSent *sent_cb)
+{
+    NetPacket *packet;
+
+    packet = qemu_malloc(sizeof(NetPacket) + size);
+    packet->sender = sender;
+    packet->size = size;
+    packet->sent_cb = sent_cb;
+    memcpy(packet->data, buf, size);
+
+    QTAILQ_INSERT_TAIL(&queue->packets, packet, entry);
+
+    return size;
+}
+
+static ssize_t qemu_net_queue_append_iov(NetQueue *queue,
+                                         VLANClientState *sender,
+                                         const struct iovec *iov,
+                                         int iovcnt,
+                                         NetPacketSent *sent_cb)
+{
+    NetPacket *packet;
+    size_t max_len = 0;
+    int i;
+
+    for (i = 0; i < iovcnt; i++) {
+        max_len += iov[i].iov_len;
+    }
+
+    packet = qemu_malloc(sizeof(NetPacket) + max_len);
+    packet->sender = sender;
+    packet->sent_cb = sent_cb;
+    packet->size = 0;
+
+    for (i = 0; i < iovcnt; i++) {
+        size_t len = iov[i].iov_len;
+
+        memcpy(packet->data + packet->size, iov[i].iov_base, len);
+        packet->size += len;
+    }
+
+    QTAILQ_INSERT_TAIL(&queue->packets, packet, entry);
+
+    return packet->size;
+}
+
+static ssize_t qemu_net_queue_deliver(NetQueue *queue,
+                                      VLANClientState *sender,
+                                      const uint8_t *data,
+                                      size_t size)
+{
+    ssize_t ret = -1;
+
+    queue->delivering = 1;
+    ret = queue->deliver(sender, data, size, queue->opaque);
+    queue->delivering = 0;
+
+    return ret;
+}
+
+static ssize_t qemu_net_queue_deliver_iov(NetQueue *queue,
+                                          VLANClientState *sender,
+                                          const struct iovec *iov,
+                                          int iovcnt)
+{
+    ssize_t ret = -1;
+
+    queue->delivering = 1;
+    ret = queue->deliver_iov(sender, iov, iovcnt, queue->opaque);
+    queue->delivering = 0;
+
+    return ret;
+}
+
+ssize_t qemu_net_queue_send(NetQueue *queue,
+                            VLANClientState *sender,
+                            const uint8_t *data,
+                            size_t size,
+                            NetPacketSent *sent_cb)
+{
+    ssize_t ret;
+
+    if (queue->delivering) {
+        return qemu_net_queue_append(queue, sender, data, size, NULL);
+    }
+
+    ret = qemu_net_queue_deliver(queue, sender, data, size);
+    if (ret == 0 && sent_cb != NULL) {
+        qemu_net_queue_append(queue, sender, data, size, sent_cb);
+        return 0;
+    }
+
+    qemu_net_queue_flush(queue);
+
+    return ret;
+}
+
+ssize_t qemu_net_queue_send_iov(NetQueue *queue,
+                                VLANClientState *sender,
+                                const struct iovec *iov,
+                                int iovcnt,
+                                NetPacketSent *sent_cb)
+{
+    ssize_t ret;
+
+    if (queue->delivering) {
+        return qemu_net_queue_append_iov(queue, sender, iov, iovcnt, NULL);
+    }
+
+    ret = qemu_net_queue_deliver_iov(queue, sender, iov, iovcnt);
+    if (ret == 0 && sent_cb != NULL) {
+        qemu_net_queue_append_iov(queue, sender, iov, iovcnt, sent_cb);
+        return 0;
+    }
+
+    qemu_net_queue_flush(queue);
+
+    return ret;
+}
+
+void qemu_net_queue_purge(NetQueue *queue, VLANClientState *from)
+{
+    NetPacket *packet, *next;
+
+    QTAILQ_FOREACH_SAFE(packet, &queue->packets, entry, next) {
+        if (packet->sender == from) {
+            QTAILQ_REMOVE(&queue->packets, packet, entry);
+            qemu_free(packet);
+        }
+    }
+}
+
+void qemu_net_queue_flush(NetQueue *queue)
+{
+    while (!QTAILQ_EMPTY(&queue->packets)) {
+        NetPacket *packet;
+        int ret;
+
+        packet = QTAILQ_FIRST(&queue->packets);
+        QTAILQ_REMOVE(&queue->packets, packet, entry);
+
+        ret = qemu_net_queue_deliver(queue,
+                                     packet->sender,
+                                     packet->data,
+                                     packet->size);
+        if (ret == 0 && packet->sent_cb != NULL) {
+            QTAILQ_INSERT_HEAD(&queue->packets, packet, entry);
+            break;
+        }
+
+        if (packet->sent_cb) {
+            packet->sent_cb(packet->sender, ret);
+        }
+
+        qemu_free(packet);
+    }
+}