Re: [Qemu-devel] [PATCH 09/12] netfilter: add a netbuffer filter

[Yang Hongyang <yanghy@cn.fujitsu.com>]

On 07/30/2015 01:13 PM, Jason Wang wrote:
[...]
>> +    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?

A good idea, I also thought about this, but a question, should we make
this type option a mandatory to netfilter object or optional? if it's
optional, the default will be "all"

>
>> +        /* 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
>
> .
>

-- 
Thanks,
Yang.