net/queue: introduce NetQueueDeliverFunc

net/queue.c has logic to send/queue/flush packets but a
qemu_deliver_packet_iov() call is hardcoded. Abstract this
func so that we can use our own deliver function in netfilter.

Signed-off-by: Yang Hongyang <yanghy@cn.fujitsu.com>
Cc: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>

include/net/queue.h

@@ -34,7 +34,18 @@ typedef void (NetPacketSent) (NetClientState *sender, ssize_t ret);
 #define QEMU_NET_PACKET_FLAG_NONE  0
 #define QEMU_NET_PACKET_FLAG_RAW  (1<<0)
 
-NetQueue *qemu_new_net_queue(void *opaque);
+/* Returns:
+ *   >0 - success
+ *    0 - queue packet for future redelivery
+ *   <0 - failure (discard packet)
+ */
+typedef ssize_t (NetQueueDeliverFunc)(NetClientState *sender,
+                                      unsigned flags,
+                                      const struct iovec *iov,
+                                      int iovcnt,
+                                      void *opaque);
+
+NetQueue *qemu_new_net_queue(NetQueueDeliverFunc *deliver, void *opaque);
 
 void qemu_del_net_queue(NetQueue *queue);
 

net/net.c

@@ -286,7 +286,7 @@ static void qemu_net_client_setup(NetClientState *nc,
     }
     QTAILQ_INSERT_TAIL(&net_clients, nc, next);
 
-    nc->incoming_queue = qemu_new_net_queue(nc);
+    nc->incoming_queue = qemu_new_net_queue(qemu_deliver_packet_iov, nc);
     nc->destructor = destructor;
     QTAILQ_INIT(&nc->filters);
 }

net/queue.c

@@ -52,13 +52,14 @@ struct NetQueue {
     void *opaque;
     uint32_t nq_maxlen;
     uint32_t nq_count;
+    NetQueueDeliverFunc *deliver;
 
     QTAILQ_HEAD(packets, NetPacket) packets;
 
     unsigned delivering : 1;
 };
 
-NetQueue *qemu_new_net_queue(void *opaque)
+NetQueue *qemu_new_net_queue(NetQueueDeliverFunc *deliver, void *opaque)
 {
     NetQueue *queue;
 
@@ -67,6 +68,7 @@ NetQueue *qemu_new_net_queue(void *opaque)
     queue->opaque = opaque;
     queue->nq_maxlen = 10000;
     queue->nq_count = 0;
+    queue->deliver = deliver;
 
     QTAILQ_INIT(&queue->packets);
 
@@ -158,7 +160,7 @@ static ssize_t qemu_net_queue_deliver(NetQueue *queue,
     };
 
     queue->delivering = 1;
-    ret = qemu_deliver_packet_iov(sender, flags, &iov, 1, queue->opaque);
+    ret = queue->deliver(sender, flags, &iov, 1, queue->opaque);
     queue->delivering = 0;
 
     return ret;
@@ -173,7 +175,7 @@ static ssize_t qemu_net_queue_deliver_iov(NetQueue *queue,
     ssize_t ret = -1;
 
     queue->delivering = 1;
-    ret = qemu_deliver_packet_iov(sender, flags, iov, iovcnt, queue->opaque);
+    ret = queue->deliver(sender, flags, iov, iovcnt, queue->opaque);
     queue->delivering = 0;
 
     return ret;