22dc8663d9
The memory API allows DMA into NIC's MMIO area. This means the NIC's RX routine must be reentrant. Instead of auditing all the NIC, we can simply detect the reentrancy and return early. The queue->delivering is set and cleared by qemu_net_queue_deliver() for other queue helpers to know whether the delivering in on going (NIC's receive is being called). We can check it and return early in qemu_net_queue_flush() to forbid reentrant RX. Signed-off-by: Jason Wang <jasowang@redhat.com>
283 lines
8.0 KiB
C
283 lines
8.0 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_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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