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![Jason Wang](/assets/img/avatar_default.png)
Some NIC supports loopback mode and this is done by calling nc->info->receive() directly which in fact suppresses the effort of reentrancy check that is done in qemu_net_queue_send(). Unfortunately we can't use qemu_net_queue_send() here since for loopback there's no sender as peer, so this patch introduce a qemu_receive_packet() which is used for implementing loopback mode for a NIC with this check. NIC that supports loopback mode will be converted to this helper. This is intended to address CVE-2021-3416. Cc: Prasad J Pandit <ppandit@redhat.com> Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com> Cc: qemu-stable@nongnu.org Signed-off-by: Jason Wang <jasowang@redhat.com>
305 lines
8.6 KiB
C
305 lines
8.6 KiB
C
/*
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* Copyright (c) 2003-2008 Fabrice Bellard
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* Copyright (c) 2009 Red Hat, Inc.
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy
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* of this software and associated documentation files (the "Software"), to deal
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* in the Software without restriction, including without limitation the rights
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* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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* copies of the Software, and to permit persons to whom the Software is
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* furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in
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* all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
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* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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* THE SOFTWARE.
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*/
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#include "qemu/osdep.h"
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#include "net/queue.h"
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#include "qemu/queue.h"
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#include "net/net.h"
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/* The delivery handler may only return zero if it will call
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* qemu_net_queue_flush() when it determines that it is once again able
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* to deliver packets. It must also call qemu_net_queue_purge() in its
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* cleanup path.
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*
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* If a sent callback is provided to send(), the caller must handle a
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* zero return from the delivery handler by not sending any more packets
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* until we have invoked the callback. Only in that case will we queue
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* the packet.
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*
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* If a sent callback isn't provided, we just drop the packet to avoid
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* unbounded queueing.
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*/
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struct NetPacket {
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QTAILQ_ENTRY(NetPacket) entry;
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NetClientState *sender;
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unsigned flags;
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int size;
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NetPacketSent *sent_cb;
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uint8_t data[];
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};
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struct NetQueue {
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void *opaque;
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uint32_t nq_maxlen;
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uint32_t nq_count;
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NetQueueDeliverFunc *deliver;
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QTAILQ_HEAD(, NetPacket) packets;
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unsigned delivering : 1;
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};
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NetQueue *qemu_new_net_queue(NetQueueDeliverFunc *deliver, void *opaque)
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{
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NetQueue *queue;
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queue = g_new0(NetQueue, 1);
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queue->opaque = opaque;
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queue->nq_maxlen = 10000;
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queue->nq_count = 0;
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queue->deliver = deliver;
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QTAILQ_INIT(&queue->packets);
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queue->delivering = 0;
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return queue;
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}
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void qemu_del_net_queue(NetQueue *queue)
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{
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NetPacket *packet, *next;
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QTAILQ_FOREACH_SAFE(packet, &queue->packets, entry, next) {
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QTAILQ_REMOVE(&queue->packets, packet, entry);
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g_free(packet);
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}
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g_free(queue);
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}
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static void qemu_net_queue_append(NetQueue *queue,
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NetClientState *sender,
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unsigned flags,
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const uint8_t *buf,
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size_t size,
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NetPacketSent *sent_cb)
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{
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NetPacket *packet;
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if (queue->nq_count >= queue->nq_maxlen && !sent_cb) {
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return; /* drop if queue full and no callback */
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}
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packet = g_malloc(sizeof(NetPacket) + size);
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packet->sender = sender;
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packet->flags = flags;
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packet->size = size;
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packet->sent_cb = sent_cb;
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memcpy(packet->data, buf, size);
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queue->nq_count++;
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QTAILQ_INSERT_TAIL(&queue->packets, packet, entry);
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}
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void qemu_net_queue_append_iov(NetQueue *queue,
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NetClientState *sender,
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unsigned flags,
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const struct iovec *iov,
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int iovcnt,
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NetPacketSent *sent_cb)
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{
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NetPacket *packet;
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size_t max_len = 0;
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int i;
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if (queue->nq_count >= queue->nq_maxlen && !sent_cb) {
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return; /* drop if queue full and no callback */
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}
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for (i = 0; i < iovcnt; i++) {
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max_len += iov[i].iov_len;
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}
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packet = g_malloc(sizeof(NetPacket) + max_len);
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packet->sender = sender;
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packet->sent_cb = sent_cb;
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packet->flags = flags;
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packet->size = 0;
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for (i = 0; i < iovcnt; i++) {
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size_t len = iov[i].iov_len;
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memcpy(packet->data + packet->size, iov[i].iov_base, len);
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packet->size += len;
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}
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queue->nq_count++;
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QTAILQ_INSERT_TAIL(&queue->packets, packet, entry);
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}
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static ssize_t qemu_net_queue_deliver(NetQueue *queue,
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NetClientState *sender,
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unsigned flags,
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const uint8_t *data,
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size_t size)
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{
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ssize_t ret = -1;
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struct iovec iov = {
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.iov_base = (void *)data,
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.iov_len = size
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};
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queue->delivering = 1;
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ret = queue->deliver(sender, flags, &iov, 1, queue->opaque);
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queue->delivering = 0;
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return ret;
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}
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static ssize_t qemu_net_queue_deliver_iov(NetQueue *queue,
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NetClientState *sender,
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unsigned flags,
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const struct iovec *iov,
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int iovcnt)
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{
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ssize_t ret = -1;
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queue->delivering = 1;
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ret = queue->deliver(sender, flags, iov, iovcnt, queue->opaque);
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queue->delivering = 0;
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return ret;
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}
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ssize_t qemu_net_queue_receive(NetQueue *queue,
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const uint8_t *data,
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size_t size)
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{
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if (queue->delivering) {
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return 0;
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}
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return qemu_net_queue_deliver(queue, NULL, 0, data, size);
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}
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ssize_t qemu_net_queue_receive_iov(NetQueue *queue,
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const struct iovec *iov,
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int iovcnt)
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{
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if (queue->delivering) {
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return 0;
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}
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return qemu_net_queue_deliver_iov(queue, NULL, 0, iov, iovcnt);
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}
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ssize_t qemu_net_queue_send(NetQueue *queue,
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NetClientState *sender,
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unsigned flags,
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const uint8_t *data,
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size_t size,
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NetPacketSent *sent_cb)
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{
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ssize_t ret;
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if (queue->delivering || !qemu_can_send_packet(sender)) {
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qemu_net_queue_append(queue, sender, flags, data, size, sent_cb);
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return 0;
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}
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ret = qemu_net_queue_deliver(queue, sender, flags, data, size);
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if (ret == 0) {
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qemu_net_queue_append(queue, sender, flags, data, size, sent_cb);
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return 0;
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}
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qemu_net_queue_flush(queue);
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return ret;
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}
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ssize_t qemu_net_queue_send_iov(NetQueue *queue,
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NetClientState *sender,
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unsigned flags,
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const struct iovec *iov,
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int iovcnt,
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NetPacketSent *sent_cb)
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{
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ssize_t ret;
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if (queue->delivering || !qemu_can_send_packet(sender)) {
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qemu_net_queue_append_iov(queue, sender, flags, iov, iovcnt, sent_cb);
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return 0;
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}
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ret = qemu_net_queue_deliver_iov(queue, sender, flags, iov, iovcnt);
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if (ret == 0) {
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qemu_net_queue_append_iov(queue, sender, flags, iov, iovcnt, sent_cb);
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return 0;
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}
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qemu_net_queue_flush(queue);
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return ret;
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}
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void qemu_net_queue_purge(NetQueue *queue, NetClientState *from)
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{
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NetPacket *packet, *next;
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QTAILQ_FOREACH_SAFE(packet, &queue->packets, entry, next) {
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if (packet->sender == from) {
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QTAILQ_REMOVE(&queue->packets, packet, entry);
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queue->nq_count--;
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if (packet->sent_cb) {
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packet->sent_cb(packet->sender, 0);
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}
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g_free(packet);
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}
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}
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}
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bool qemu_net_queue_flush(NetQueue *queue)
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{
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if (queue->delivering)
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return false;
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while (!QTAILQ_EMPTY(&queue->packets)) {
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NetPacket *packet;
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int ret;
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packet = QTAILQ_FIRST(&queue->packets);
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QTAILQ_REMOVE(&queue->packets, packet, entry);
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queue->nq_count--;
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ret = qemu_net_queue_deliver(queue,
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packet->sender,
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packet->flags,
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packet->data,
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packet->size);
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if (ret == 0) {
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queue->nq_count++;
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QTAILQ_INSERT_HEAD(&queue->packets, packet, entry);
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return false;
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}
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if (packet->sent_cb) {
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packet->sent_cb(packet->sender, ret);
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}
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g_free(packet);
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}
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return true;
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}
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