On 07/29/2015 06:51 PM, Yang Hongyang wrote:
> This filter is to buffer/release packets, this feature can be used
> when using macrocheckpoing, 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,interval=1000
>
> NOTE:
> the scale of interval is microsecond.
> API to release packets and interval support will be added
> by the following 2 patches.
>
> Signed-off-by: Yang Hongyang <yan...@cn.fujitsu.com>
> ---
> net/Makefile.objs | 1 +
> net/filter-buffer.c | 127
> ++++++++++++++++++++++++++++++++++++++++++++++++++++
> net/filter.c | 2 +
> net/filters.h | 17 +++++++
> qapi-schema.json | 13 +++++-
> 5 files changed, 159 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..628e66f
> --- /dev/null
> +++ b/net/filter-buffer.c
> @@ -0,0 +1,127 @@
> +/*
> + * 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"
> +
> +typedef struct FILTERBUFFERState {
> + NetFilterState nf;
> + NetClientState dummy; /* used to send buffered packets */
Why need this? Couldn't we just infer this from NetFilterState?
> + NetQueue *incoming_queue;
> + NetQueue *inflight_queue;
> +} 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->flags & QEMU_NET_PACKET_FLAG_RAW) {
> + qemu_send_packet_raw(&s->dummy, packet->data, packet->size);
> + } else {
> + qemu_send_packet_async(&s->dummy, 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);
> + }
> +
> + if (queue && QTAILQ_EMPTY(&queue->packets)) {
Under what condition queue->packet could be not empty here? And I don't
get the point that why a inflight_queue is needed.
> + g_free(queue);
> + s->inflight_queue = NULL;
> + }
> +}
> +
> +/* filter APIs */
> +static ssize_t filter_buffer_receive(NetFilterState *nf,
> + NetClientState *sender,
> + unsigned flags,
> + const uint8_t *data,
> + size_t size)
> +{
> + FILTERBUFFERState *s = DO_UPCAST(FILTERBUFFERState, nf, nf);
> + NetQueue *queue = s->incoming_queue;
> +
> + if (!sender->info) {
> + /* This must be a dummy NetClientState, do nothing */
> + return 0;
> + }
> +
> + if (sender->info->type == NET_CLIENT_OPTIONS_KIND_NIC) {
> + /* we only buffer guest output packets */
> + qemu_net_queue_append(queue, sender, flags, data, size,
> + packet_send_completed);
This may brings some confusion for user. Since the name is 'netbuffer'.
Maybe we can change the filter to be ingress or out or both? Like:
-device virtio-net-pci,id=virtio0
-netfilter buffer,id=filter0,dev=virtio0,interval=1000,type=out
Then we can just try to enqueue the packet when virtio-net-pci is sender?
> + /* Now that we have buffered the packet, return sucess */
> + return size;
> + }
> +
> + return 0;
> +}
> +
> +static void filter_buffer_cleanup(NetFilterState *nf)
> +{
> + FILTERBUFFERState *s = DO_UPCAST(FILTERBUFFERState, nf, nf);
> +
> + /* flush inflight packets */
> + filter_buffer_flush(nf);
> + /* flush incoming packets */
> + s->inflight_queue = s->incoming_queue;
> + s->incoming_queue = NULL;
> + filter_buffer_flush(nf);
> +
> + return;
> +}
> +
> +
> +static NetFilterInfo net_filter_buffer_info = {
> + .type = NET_FILTER_OPTIONS_KIND_BUFFER,
> + .size = sizeof(FILTERBUFFERState),
> + .receive = filter_buffer_receive,
> + .cleanup = filter_buffer_cleanup,
> +};
> +
> +int net_init_filter_buffer(const NetFilterOptions *opts, const char *name,
> + NetClientState *netdev, Error **errp)
> +{
> + NetFilterState *nf;
> + FILTERBUFFERState *s;
> +
> + assert(opts->kind == NET_FILTER_OPTIONS_KIND_BUFFER);
> +
> + nf = qemu_new_net_filter(&net_filter_buffer_info, netdev, "buffer",
> name);
> + s = DO_UPCAST(FILTERBUFFERState, nf, nf);
> + /*
> + * we need the dummy NetClientState to send packets in order to avoid
> + * receive packets again.
> + * we are buffering guest output packets, our buffered packets should be
> + * sent to real network backend, so dummy's peer should be that backend.
> + */
> + s->dummy.peer = netdev;
> + s->incoming_queue = qemu_new_net_queue(nf);
> +
> + return 0;
> +}
> diff --git a/net/filter.c b/net/filter.c
> index 50fb837..e741e2a 100644
> --- a/net/filter.c
> +++ b/net/filter.c
> @@ -18,6 +18,7 @@
>
> #include "net/filter.h"
> #include "net/net.h"
> +#include "filters.h"
>
> static QTAILQ_HEAD(, NetFilterState) net_filters;
>
> @@ -152,6 +153,7 @@ typedef int (NetFilterInit)(const NetFilterOptions *opts,
>
> static
> NetFilterInit * const net_filter_init_fun[NET_FILTER_OPTIONS_KIND_MAX] = {
> + [NET_FILTER_OPTIONS_KIND_BUFFER] = net_init_filter_buffer,
> };
>
> static int net_filter_init1(const NetFilter *netfilter, Error **errp)
> diff --git a/net/filters.h b/net/filters.h
> new file mode 100644
> index 0000000..6c249b8
> --- /dev/null
> +++ b/net/filters.h
> @@ -0,0 +1,17 @@
> +/*
> + * Copyright (c) 2015 FUJITSU LIMITED
> + *
> + * This work is licensed under the terms of the GNU GPL, version 2 or
> + * later. See the COPYING file in the top-level directory.
> + */
> +
> +#ifndef QEMU_NET_FILTERS_H
> +#define QEMU_NET_FILTERS_H
> +
> +#include "net/net.h"
> +#include "net/filter.h"
> +
> +int net_init_filter_buffer(const NetFilterOptions *opts, const char *name,
> + NetClientState *netdev, Error **errp);
> +
> +#endif /* QEMU_NET_FILTERS_H */
> diff --git a/qapi-schema.json b/qapi-schema.json
> index 1fc6390..67e00a0 100644
> --- a/qapi-schema.json
> +++ b/qapi-schema.json
> @@ -2577,6 +2577,16 @@
> { 'command': 'netfilter_del', 'data': {'id': 'str'} }
>
> ##
> +# @NetFilterBufferOptions
> +#
> +# a netbuffer filter for network backend.
> +#
> +# Since 2.5
> +##
> +{ 'struct': 'NetFilterBufferOptions',
> + 'data': { } }
> +
> +##
> # @NetFilterOptions
> #
> # A discriminated record of network filters.
> @@ -2585,7 +2595,8 @@
> #
> ##
> { 'union': 'NetFilterOptions',
> - 'data': { } }
> + 'data': {
> + 'buffer': 'NetFilterBufferOptions'} }
>
> ##
> # @NetFilter
