Re: [Qemu-devel] [RFC PATCH V2 1/3] filter-rewriter: introduce filter-rewriter initialization

[Jason Wang <jasowang@redhat.com>]

On 2016年07月02日 14:22, Zhang Chen wrote:
> Filter-rewriter is a part of COLO project.
> It will rewrite some of secondary packet to make
> secondary guest's connection established successfully.

Probably need to be more verbose here. E.g we only care about tcp and 
only rewrite ack now.

>
> usage:
>
> colo secondary:
> -object filter-redirector,id=f1,netdev=hn0,queue=tx,indev=red0
> -object filter-redirector,id=f2,netdev=hn0,queue=rx,outdev=red1
> -object filter-rewriter,id=rew0,netdev=hn0,queue=all
>
> Signed-off-by: Zhang Chen <zhangchen.fnst@cn.fujitsu.com>
> Signed-off-by: Li Zhijian <lizhijian@cn.fujitsu.com>
> Signed-off-by: Wen Congyang <wency@cn.fujitsu.com>
> ---
>   net/Makefile.objs     |   1 +
>   net/filter-rewriter.c | 112 ++++++++++++++++++++++++++++++++++++++++++++++++++
>   qemu-options.hx       |  10 +++++
>   vl.c                  |   3 +-
>   4 files changed, 125 insertions(+), 1 deletion(-)
>   create mode 100644 net/filter-rewriter.c
>
> diff --git a/net/Makefile.objs b/net/Makefile.objs
> index 119589f..645bd10 100644
> --- a/net/Makefile.objs
> +++ b/net/Makefile.objs
> @@ -18,3 +18,4 @@ common-obj-y += filter-buffer.o
>   common-obj-y += filter-mirror.o
>   common-obj-y += colo-compare.o
>   common-obj-y += colo-base.o
> +common-obj-y += filter-rewriter.o
> diff --git a/net/filter-rewriter.c b/net/filter-rewriter.c
> new file mode 100644
> index 0000000..08b015d
> --- /dev/null
> +++ b/net/filter-rewriter.c
> @@ -0,0 +1,112 @@
> +/*
> + * Copyright (c) 2016 HUAWEI TECHNOLOGIES CO., LTD.
> + * Copyright (c) 2016 FUJITSU LIMITED
> + * Copyright (c) 2016 Intel Corporation
> + *
> + * Author: Zhang Chen <zhangchen.fnst@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 "qemu/osdep.h"
> +#include "net/colo-base.h"
> +#include "net/filter.h"
> +#include "net/net.h"
> +#include "qemu-common.h"
> +#include "qapi/error.h"
> +#include "qapi/qmp/qerror.h"
> +#include "qapi-visit.h"
> +#include "qom/object.h"
> +#include "qemu/main-loop.h"
> +#include "qemu/iov.h"
> +#include "net/checksum.h"
> +
> +#define FILTER_COLO_REWRITER(obj) \
> +    OBJECT_CHECK(RewriterState, (obj), TYPE_FILTER_REWRITER)
> +
> +#define TYPE_FILTER_REWRITER "filter-rewriter"
> +
> +enum {
> +    PRIMARY = 0,
> +    SECONDARY,
> +};
> +
> +typedef struct RewriterState {
> +    NetFilterState parent_obj;
> +    /* connection list: the connections belonged to this NIC could be found
> +     * in this list.
> +     * element type: Connection
> +     */
> +    GQueue conn_list;
> +    NetQueue *incoming_queue;
> +    /* to protect conn_list */
> +    QemuMutex conn_list_lock;
> +    /* hashtable to save connection */
> +    GHashTable *connection_track_table;
> +    /* to save unprocessed_connections */
> +    GQueue unprocessed_connections;
> +    /* current hash size */
> +    uint32_t hashtable_size;
> +} RewriterState;
> +
> +static ssize_t colo_rewriter_receive_iov(NetFilterState *nf,
> +                                         NetClientState *sender,
> +                                         unsigned flags,
> +                                         const struct iovec *iov,
> +                                         int iovcnt,
> +                                         NetPacketSent *sent_cb)
> +{
> +    /*
> +     * if we get tcp packet
> +     * we will rewrite it to make secondary guest's
> +     * connection established successfully
> +     */
> +    return 0;
> +}
> +
> +static void colo_rewriter_cleanup(NetFilterState *nf)
> +{
> +    RewriterState *s = FILTER_COLO_REWRITER(nf);
> +
> +    qemu_mutex_destroy(&s->conn_list_lock);
> +    g_queue_free(&s->conn_list);
> +}
> +
> +static void colo_rewriter_setup(NetFilterState *nf, Error **errp)
> +{
> +    RewriterState *s = FILTER_COLO_REWRITER(nf);
> +
> +    g_queue_init(&s->conn_list);
> +    qemu_mutex_init(&s->conn_list_lock);
> +    s->hashtable_size = 0;
> +
> +    s->connection_track_table = g_hash_table_new_full(connection_key_hash,
> +                                                      connection_key_equal,
> +                                                      g_free,
> +                                                      connection_destroy);
> +    s->incoming_queue = qemu_new_net_queue(qemu_netfilter_pass_to_next, nf);
> +}
> +
> +static void colo_rewriter_class_init(ObjectClass *oc, void *data)
> +{
> +    NetFilterClass *nfc = NETFILTER_CLASS(oc);
> +
> +    nfc->setup = colo_rewriter_setup;
> +    nfc->cleanup = colo_rewriter_cleanup;
> +    nfc->receive_iov = colo_rewriter_receive_iov;
> +}
> +
> +static const TypeInfo colo_rewriter_info = {
> +    .name = TYPE_FILTER_REWRITER,
> +    .parent = TYPE_NETFILTER,
> +    .class_init = colo_rewriter_class_init,
> +    .instance_size = sizeof(RewriterState),
> +};
> +
> +static void register_types(void)
> +{
> +    type_register_static(&colo_rewriter_info);
> +}
> +
> +type_init(register_types);
> diff --git a/qemu-options.hx b/qemu-options.hx
> index 14bade5..d7ab165 100644
> --- a/qemu-options.hx
> +++ b/qemu-options.hx
> @@ -3859,6 +3859,16 @@ Create a filter-redirector we need to differ outdev id from indev id, id can not
>   be the same. we can just use indev or outdev, but at least one of indev or outdev
>   need to be specified.
>   
> +@item -object filter-rewriter,id=@var{id},netdev=@var{netdevid},rewriter-mode=@var{mode}[,queue=@var{all|rx|tx}]
> +
> +Filter-rewriter is a part of COLO project.It will rewrite some of secondary packet.

Need to be more verbose here.

> +
> +usage:
> +colo secondary:
> +-object filter-redirector,id=f1,netdev=hn0,queue=tx,indev=red0
> +-object filter-redirector,id=f2,netdev=hn0,queue=rx,outdev=red1
> +-object filter-rewriter,id=rew0,netdev=hn0,queue=all
> +
>   @item -object filter-dump,id=@var{id},netdev=@var{dev},file=@var{filename}][,maxlen=@var{len}]
>   
>   Dump the network traffic on netdev @var{dev} to the file specified by
> diff --git a/vl.c b/vl.c
> index c6b9a6f..b47be6a 100644
> --- a/vl.c
> +++ b/vl.c
> @@ -2866,7 +2866,8 @@ static bool object_create_initial(const char *type)
>           g_str_equal(type, "filter-dump") ||
>           g_str_equal(type, "filter-mirror") ||
>           g_str_equal(type, "filter-redirector") ||
> -        g_str_equal(type, "colo-compare")) {
> +        g_str_equal(type, "colo-compare") ||
> +        g_str_equal(type, "filter-rewriter")) {

So this makes the patch can't be applied cleanly on master.

And I think we don't want to manually compare 100 kinds of filters in 
the future. How about doing something better, e.g:

- introduce something like filter_register_type()
- recored the name of the type in a list
- iterate it here

?

>           return false;
>       }
>