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[Qemu-devel] [PATCH 2/3] net: fix usbnet_receive() packet drops
From: |
Stefan Hajnoczi |
Subject: |
[Qemu-devel] [PATCH 2/3] net: fix usbnet_receive() packet drops |
Date: |
Fri, 24 Aug 2012 14:39:52 +0100 |
The USB network interface has a single buffer which the guest reads
from. This patch prevents multiple calls to usbnet_receive() from
clobbering the input buffer. Instead we queue packets until buffer
space becomes available again.
This is inspired by virtio-net and e1000 rxbuf handling.
Signed-off-by: Stefan Hajnoczi <address@hidden>
---
hw/usb/dev-network.c | 19 ++++++++++++++++---
1 file changed, 16 insertions(+), 3 deletions(-)
diff --git a/hw/usb/dev-network.c b/hw/usb/dev-network.c
index 0b5cb71..e4a4359 100644
--- a/hw/usb/dev-network.c
+++ b/hw/usb/dev-network.c
@@ -1001,6 +1001,13 @@ static int rndis_keepalive_response(USBNetState *s,
return 0;
}
+/* Prepare to receive the next packet */
+static void usb_net_reset_in_buf(USBNetState *s)
+{
+ s->in_ptr = s->in_len = 0;
+ qemu_flush_queued_packets(&s->nic->nc);
+}
+
static int rndis_parse(USBNetState *s, uint8_t *data, int length)
{
uint32_t msg_type;
@@ -1025,7 +1032,8 @@ static int rndis_parse(USBNetState *s, uint8_t *data, int
length)
case RNDIS_RESET_MSG:
rndis_clear_responsequeue(s);
- s->out_ptr = s->in_ptr = s->in_len = 0;
+ s->out_ptr = 0;
+ usb_net_reset_in_buf(s);
return rndis_reset_response(s, (rndis_reset_msg_type *) data);
case RNDIS_KEEPALIVE_MSG:
@@ -1135,7 +1143,7 @@ static int usb_net_handle_datain(USBNetState *s,
USBPacket *p)
int ret = USB_RET_NAK;
if (s->in_ptr > s->in_len) {
- s->in_ptr = s->in_len = 0;
+ usb_net_reset_in_buf(s);
ret = USB_RET_NAK;
return ret;
}
@@ -1152,7 +1160,7 @@ static int usb_net_handle_datain(USBNetState *s,
USBPacket *p)
if (s->in_ptr >= s->in_len &&
(is_rndis(s) || (s->in_len & (64 - 1)) || !ret)) {
/* no short packet necessary */
- s->in_ptr = s->in_len = 0;
+ usb_net_reset_in_buf(s);
}
#ifdef TRAFFIC_DEBUG
@@ -1263,6 +1271,11 @@ static ssize_t usbnet_receive(NetClientState *nc, const
uint8_t *buf, size_t siz
return -1;
}
+ /* Only accept packet if input buffer is empty */
+ if (s->in_len > 0) {
+ return 0;
+ }
+
if (is_rndis(s)) {
struct rndis_packet_msg_type *msg;
--
1.7.10.4