On 08/04/2015 02:05 PM, Yang Hongyang wrote:
> On 08/04/2015 01:03 PM, Jason Wang wrote:
>>
>>
>> On 08/03/2015 04:30 PM, Yang Hongyang wrote:
>>> This filter is to buffer/release packets, this feature can be used
>>> when using MicroCheckpointing, or other Remus like VM FT solutions, you
>>> can also use it to simulate the network delay.
>>> It has an interval option, if supplied, this filter will release
>>> packets by interval.
>>>
>>> Usage:
>>> -netdev tap,id=bn0
>>> -netfilter buffer,id=f0,netdev=bn0,chain=in,interval=1000
>>>
>>> NOTE:
>>> the scale of interval is microsecond.
>>>
>>> Signed-off-by: Yang Hongyang <yan...@cn.fujitsu.com>
>>> ---
>>> v3: check packet's sender and sender->peer when flush it
>>> ---
>>> net/Makefile.objs | 1 +
>>> net/filter-buffer.c | 162
>>> ++++++++++++++++++++++++++++++++++++++++++++++++++++
>>> net/filter.c | 2 +
>>> net/filters.h | 17 ++++++
>>> qapi-schema.json | 18 +++++-
>>> 5 files changed, 199 insertions(+), 1 deletion(-)
>>> create mode 100644 net/filter-buffer.c
>>> create mode 100644 net/filters.h
>>>
>>> diff --git a/net/Makefile.objs b/net/Makefile.objs
>>> index 914aec0..5fa2f97 100644
>>> --- a/net/Makefile.objs
>>> +++ b/net/Makefile.objs
>>> @@ -14,3 +14,4 @@ common-obj-$(CONFIG_SLIRP) += slirp.o
>>> common-obj-$(CONFIG_VDE) += vde.o
>>> common-obj-$(CONFIG_NETMAP) += netmap.o
>>> common-obj-y += filter.o
>>> +common-obj-y += filter-buffer.o
>>> diff --git a/net/filter-buffer.c b/net/filter-buffer.c
>>> new file mode 100644
>>> index 0000000..1547765
>>> --- /dev/null
>>> +++ b/net/filter-buffer.c
>>> @@ -0,0 +1,162 @@
>>> +/*
>>> + * Copyright (c) 2015 FUJITSU LIMITED
>>> + * Author: Yang Hongyang <yan...@cn.fujitsu.com>
>>> + *
>>> + * This work is licensed under the terms of the GNU GPL, version 2 or
>>> + * later. See the COPYING file in the top-level directory.
>>> + */
>>> +
>>> +#include "net/filter.h"
>>> +#include "net/queue.h"
>>> +#include "filters.h"
>>> +#include "qemu-common.h"
>>> +#include "qemu/error-report.h"
>>> +#include "qemu/main-loop.h"
>>> +#include "qemu/timer.h"
>>> +#include "qemu/iov.h"
>>> +
>>> +typedef struct FILTERBUFFERState {
>>> + NetFilterState nf;
>>> + NetQueue *incoming_queue;
>>> + NetQueue *inflight_queue;
>>> + QEMUBH *flush_bh;
>>> + int64_t interval;
>>> + QEMUTimer release_timer;
>>> +} FILTERBUFFERState;
>>> +
>>> +static void packet_send_completed(NetClientState *nc, ssize_t len)
>>> +{
>>> + return;
>>> +}
>>> +
>>> +static void filter_buffer_flush(NetFilterState *nf)
>>> +{
>>> + FILTERBUFFERState *s = DO_UPCAST(FILTERBUFFERState, nf, nf);
>>> + NetQueue *queue = s->inflight_queue;
>>> + NetPacket *packet;
>>> +
>>> + while (queue && !QTAILQ_EMPTY(&queue->packets)) {
>>> + packet = QTAILQ_FIRST(&queue->packets);
>>> + QTAILQ_REMOVE(&queue->packets, packet, entry);
>>> + queue->nq_count--;
>>> +
>>> + if (packet->sender && packet->sender->peer) {
>>> + qemu_net_queue_send(packet->sender->peer->incoming_queue,
>>> + packet->sender,
>>> + packet->flags,
>>> + packet->data,
>>> + packet->size,
>>> + packet->sent_cb);
>>> + }
>>> +
>>> + /*
>>> + * now that we pass the packet to
>>> sender->peer->incoming_queue, we
>>> + * don't care the reture value here, because the peer's
>>> queue will
>>> + * take care of this packet
>>> + */
>>> + g_free(packet);
>>
>> So looks like the packet was still not passed to next filter?
>
> I didn't get your suggestion last time, sorry, will add it in next
> version.
> Just to confirm, do you mean we need to pass the packet to next filter
> instead of pass to the receiver's incoming_queue?
Yes, consider you may have two filters. First is dump and second is
buffer, I believe you still want to buffer the packet even if it has
been dumped.
> and even if we pass to next
> filter, the check of sender and it's peer is still needed, because if
> there's no receiver, it's nonsense to pass it further?
Yes.
>
>>
>>> + }
>>> +
>>> + g_free(queue);
>>> + s->inflight_queue = NULL;
>>> +}
>>> +
>>> +static void filter_buffer_flush_bh(void *opaque)
>>> +{
>>> + FILTERBUFFERState *s = opaque;
>>> + NetFilterState *nf = &s->nf;
>>> + filter_buffer_flush(nf);
>>> +}
>>> +
>>> +static void filter_buffer_release_one(NetFilterState *nf)
>>> +{
>>> + FILTERBUFFERState *s = DO_UPCAST(FILTERBUFFERState, nf, nf);
>>> +
>>> + /* flush inflight packets */
>>> + if (s->inflight_queue) {
>>> + filter_buffer_flush(nf);
>>> + }
>>> +
>>> + s->inflight_queue = s->incoming_queue;
>>> + s->incoming_queue = qemu_new_net_queue(nf);
>>
>> So this in fact flush a brunch of packets. If yes, the name of function
>> is confusing
>
> maybe filter_buffer_release ?
>
Right.
>>
>>> + qemu_bh_schedule(s->flush_bh);
>>
>> Don't get why a bh is needed. If we could get rid of it, there's
>> probably no need for inflight_queue, and we can just drain
>> incoming_queue here.
>
> Seems we can get rid of bh, will do, thanks.
