Re: [PATCH v3 2/2] net: tulip: add .can_recieve routine
Hello Jason, +-- On Wed, 18 Mar 2020, Jason Wang wrote --+ | Right, so need to make sure qemu_flush_ququed_packets() was called when | rx_frame_len is zero. Sent patch v4, with this call. Please see when you've time. Thank you. -- Prasad J Pandit / Red Hat Product Security Team 8685 545E B54C 486B C6EB 271E E285 8B5A F050 DE8D
Re: [PATCH v3 2/2] net: tulip: add .can_recieve routine
On 2020/3/17 下午6:49, P J P wrote:
+-- On Tue, 17 Mar 2020, Jason Wang wrote --+
| > +-- On Fri, 6 Mar 2020, Stefan Hajnoczi wrote --+
| > | > +static int
| > | > +tulip_can_receive(NetClientState *nc)
| > | > +{
| > | > +TULIPState *s = qemu_get_nic_opaque(nc);
| > | > +
| > | > +if (s->rx_frame_len || tulip_rx_stopped(s)) {
| > | > +return false;
| > | > +}
|
| Btw, what's the point of checking rx_frame_len here?
tulip_can_recive() is called from tulip_receive(). IIUC non zero(0)
'rx_frame_len' hints that s->rs_frame[] buffer still has unread data bytes and
it can not receive new bytes. The check was earlier in tulip_receive().
Right, so need to make sure qemu_flush_ququed_packets() was called when
rx_frame_len is zero.
Thanks
Thank you.
--
Prasad J Pandit / Red Hat Product Security Team
8685 545E B54C 486B C6EB 271E E285 8B5A F050 DE8D
Re: [PATCH v3 2/2] net: tulip: add .can_recieve routine
+-- On Tue, 17 Mar 2020, Jason Wang wrote --+
| > +-- On Fri, 6 Mar 2020, Stefan Hajnoczi wrote --+
| > | > +static int
| > | > +tulip_can_receive(NetClientState *nc)
| > | > +{
| > | > +TULIPState *s = qemu_get_nic_opaque(nc);
| > | > +
| > | > +if (s->rx_frame_len || tulip_rx_stopped(s)) {
| > | > +return false;
| > | > +}
|
| Btw, what's the point of checking rx_frame_len here?
tulip_can_recive() is called from tulip_receive(). IIUC non zero(0)
'rx_frame_len' hints that s->rs_frame[] buffer still has unread data bytes and
it can not receive new bytes. The check was earlier in tulip_receive().
Thank you.
--
Prasad J Pandit / Red Hat Product Security Team
8685 545E B54C 486B C6EB 271E E285 8B5A F050 DE8D
Re: [PATCH v3 2/2] net: tulip: add .can_recieve routine
On 2020/3/17 上午2:01, P J P wrote:
Hello Stefan, Jason,
+-- On Fri, 6 Mar 2020, Stefan Hajnoczi wrote --+
| > +static int
| > +tulip_can_receive(NetClientState *nc)
| > +{
| > +TULIPState *s = qemu_get_nic_opaque(nc);
| > +
| > +if (s->rx_frame_len || tulip_rx_stopped(s)) {
| > +return false;
| > +}
| > +
| > +return true;
| > +}
|
| Are the required qemu_flush_queued_packets() calls in place so that
| packet transfer wakes up again when .can_receive() transitions from
| false to true?
Yes, qemu_flush_queued_packets() calls are in tulip_write(). Do we need to
call tulip_can_receive() before each call?
Probably not, just need to make sure the check in tulip_rx_stopped(s)
matches the action that triggers qemu_flush_queued_packets() in
tulip_write() is sufficient.
This to make sure net core can restore the receiving.
Btw, what's the point of checking rx_frame_len here?
Thanks
Thank you.
--
Prasad J Pandit / Red Hat Product Security Team
8685 545E B54C 486B C6EB 271E E285 8B5A F050 DE8D
Re: [PATCH v3 2/2] net: tulip: add .can_recieve routine
Hello Stefan, Jason,
+-- On Fri, 6 Mar 2020, Stefan Hajnoczi wrote --+
| > +static int
| > +tulip_can_receive(NetClientState *nc)
| > +{
| > +TULIPState *s = qemu_get_nic_opaque(nc);
| > +
| > +if (s->rx_frame_len || tulip_rx_stopped(s)) {
| > +return false;
| > +}
| > +
| > +return true;
| > +}
|
| Are the required qemu_flush_queued_packets() calls in place so that
| packet transfer wakes up again when .can_receive() transitions from
| false to true?
Yes, qemu_flush_queued_packets() calls are in tulip_write(). Do we need to
call tulip_can_receive() before each call?
Thank you.
--
Prasad J Pandit / Red Hat Product Security Team
8685 545E B54C 486B C6EB 271E E285 8B5A F050 DE8D
Re: [PATCH v3 2/2] net: tulip: add .can_recieve routine
On Tue, Mar 03, 2020 at 04:17:24PM +0530, P J P wrote:
> diff --git a/hw/net/tulip.c b/hw/net/tulip.c
> index fbe40095da..757f12c710 100644
> --- a/hw/net/tulip.c
> +++ b/hw/net/tulip.c
> @@ -229,6 +229,18 @@ static bool tulip_filter_address(TULIPState *s, const
> uint8_t *addr)
> return ret;
> }
>
> +static int
> +tulip_can_receive(NetClientState *nc)
> +{
> +TULIPState *s = qemu_get_nic_opaque(nc);
> +
> +if (s->rx_frame_len || tulip_rx_stopped(s)) {
> +return false;
> +}
> +
> +return true;
> +}
Are the required qemu_flush_queued_packets() calls in place so that
packet transfer wakes up again when .can_receive() transitions from
false to true?
(If qemu_flush_queued_packets() is missing then transmission hangs after
.can_receive() becomes false.)
Stefan
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[PATCH v3 2/2] net: tulip: add .can_recieve routine
From: Prasad J Pandit
Define .can_receive routine to do sanity checks before receiving
packet data.
Signed-off-by: Prasad J Pandit
---
hw/net/tulip.c | 15 ++-
1 file changed, 14 insertions(+), 1 deletion(-)
Update v3: define .can_receive routine
-> https://lists.gnu.org/archive/html/qemu-devel/2020-02/msg06275.html
diff --git a/hw/net/tulip.c b/hw/net/tulip.c
index fbe40095da..757f12c710 100644
--- a/hw/net/tulip.c
+++ b/hw/net/tulip.c
@@ -229,6 +229,18 @@ static bool tulip_filter_address(TULIPState *s, const
uint8_t *addr)
return ret;
}
+static int
+tulip_can_receive(NetClientState *nc)
+{
+TULIPState *s = qemu_get_nic_opaque(nc);
+
+if (s->rx_frame_len || tulip_rx_stopped(s)) {
+return false;
+}
+
+return true;
+}
+
static ssize_t tulip_receive(TULIPState *s, const uint8_t *buf, size_t size)
{
struct tulip_descriptor desc;
@@ -236,7 +248,7 @@ static ssize_t tulip_receive(TULIPState *s, const uint8_t
*buf, size_t size)
trace_tulip_receive(buf, size);
if (size < 14 || size > sizeof(s->rx_frame) - 4
-|| s->rx_frame_len || tulip_rx_stopped(s)) {
+|| !tulip_can_receive(s->nic->ncs)) {
return 0;
}
@@ -288,6 +300,7 @@ static NetClientInfo net_tulip_info = {
.type = NET_CLIENT_DRIVER_NIC,
.size = sizeof(NICState),
.receive = tulip_receive_nc,
+.can_receive = tulip_can_receive,
};
static const char *tulip_reg_name(const hwaddr addr)
--
2.24.1
