Re: [Qemu-devel] [PATCH V2 2/3] net/filter-redirector:Add filter-redirector

[Zhang Chen]

On 03/02/2016 02:31 PM, Jason Wang wrote:
> On 02/29/2016 08:23 PM, Zhang Chen wrote:
> > Filter-redirector is a netfilter plugin.
> > It gives qemu the ability to redirect net packet.
> > redirector can redirect filter's net packet to outdev.
> > and redirect indev's packet to filter.
> >
> >                               filter
> >                                 +
> >                                 |
> >                                 |
> >                redirector       |
> >                 +-------------------------+
> >                 |               |         |
> >                 |               |         |
> >                 |               |         |
> >    indev +----------------+     +---------------->  outdev
> >                 |         |               |
> >                 |         |               |
> >                 |         |               |
> >                 +-------------------------+
> >                           |
> >                           |
> >                           v
> >                        filter
> >                           |
> >                           |
> >                           v
> >                        filter------> guest
> As we've discussed, the actual destination should depend on "queue"
> parameter. E.g if queue = rx, the destination should be netdev not guest.

OK, I will fix it in V3

> > usage:
> >
> > -netdev tap,id=hn0
> > -chardev socket,id=s0,host=ip_primary,port=X,server,nowait
> > -chardev socket,id=s1,host=ip_primary,port=Y,server,nowait
> > -filter-redirector,id=r0,netdev=hn0,queue=tx/rx/all,indev=s0,outdev=s1
> >
> > Signed-off-by: Zhang Chen <address@hidden>
> > Signed-off-by: Wen Congyang <address@hidden>
> > ---
> >   net/Makefile.objs       |   1 +
> >   net/filter-redirector.c | 216 ++++++++++++++++++++++++++++++++++++++++++++++++
> >   qemu-options.hx         |   8 ++
> >   vl.c                    |   3 +-
> >   4 files changed, 227 insertions(+), 1 deletion(-)
> >   create mode 100644 net/filter-redirector.c
> >
> > diff --git a/net/Makefile.objs b/net/Makefile.objs
> > index b7c22fd..8af9932 100644
> > --- a/net/Makefile.objs
> > +++ b/net/Makefile.objs
> > @@ -16,3 +16,4 @@ common-obj-$(CONFIG_NETMAP) += netmap.o
> >   common-obj-y += filter.o
> >   common-obj-y += filter-buffer.o
> >   common-obj-y += filter-mirror.o
> > +common-obj-y += filter-redirector.o
> > diff --git a/net/filter-redirector.c b/net/filter-redirector.c
> > new file mode 100644
> > index 0000000..d0eb76d
> > --- /dev/null
> > +++ b/net/filter-redirector.c
> > @@ -0,0 +1,216 @@
> > +/*
> > + * Copyright (c) 2016 HUAWEI TECHNOLOGIES CO., LTD.
> > + * Copyright (c) 2016 FUJITSU LIMITED
> > + * Copyright (c) 2016 Intel Corporation
> > + *
> > + * Author: Zhang Chen <address@hidden>
> > + *
> > + * 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-traffic.h"
> > +
> > +#define FILTER_REDIRECTOR(obj) \
> > +    OBJECT_CHECK(TrafficState, (obj), TYPE_FILTER_REDIRECTOR)
> > +
> > +#define TYPE_FILTER_REDIRECTOR "filter-redirector"
> > +#define REDIRECT_HEADER_LEN sizeof(uint32_t)
> > +
> > +static int filter_redirector_send(NetFilterState *nf,
> > +                                   const struct iovec *iov,
> > +                                   int iovcnt)
> > +{
> > +    return filter_traffic_send(nf, iov, iovcnt);
> > +}
> > +
> > +static ssize_t filter_redirector_receive_iov(NetFilterState *nf,
> > +                                         NetClientState *sender,
> > +                                         unsigned flags,
> > +                                         const struct iovec *iov,
> > +                                         int iovcnt,
> > +                                         NetPacketSent *sent_cb)
> > +{
> > +    TrafficState *s = FILTER_REDIRECTOR(nf);
> > +    ssize_t ret = 0;
> > +
> > +    if (s->chr_out) {
> > +        ret = filter_redirector_send(nf, iov, iovcnt);
> > +        if (ret < 0) {
> > +            error_report("filter_redirector_send failed");
> > +        }
> > +        return iov_size(iov, iovcnt);
> > +    } else {
> > +        return 0;
> > +    }
> > +}
> > +
> > +static void filter_redirector_cleanup(NetFilterState *nf)
> > +{
> > +    TrafficState *s = FILTER_REDIRECTOR(nf);
> > +
> > +    if (s->chr_in) {
> > +        qemu_chr_fe_release(s->chr_in);
> > +    }
> > +    if (s->chr_out) {
> > +        qemu_chr_fe_release(s->chr_out);
> > +    }
> > +}
> > +
> > +static int redirector_chr_can_read(void *opaque)
> > +{
> > +    return REDIRECT_HEADER_LEN;
> > +}
> > +
> > +static void redirector_chr_read(void *opaque, const uint8_t *buf, int size)
> > +{
> > +    NetFilterState *nf = opaque;
> > +    TrafficState *s = FILTER_REDIRECTOR(nf);
> > +    uint32_t len;
> > +    int ret = 0;
> > +    uint8_t *recv_buf;
> > +    int offset = size;
> > +
> > +    while (offset < REDIRECT_HEADER_LEN) {
> > +        ret = s->chr_in->chr_sync_read(s->chr_in, (uint8_t *)buf + offset,
> > +                REDIRECT_HEADER_LEN - offset);
> > +        if (ret == -1 && errno == EAGAIN) {
> > +            g_usleep(100);
> > +        }
> > +        offset += ret;
> Why not use qemu_chr_fe_read_all() here?
>
> And what's better, instead of busy waiting/reading. You can save the
> partial packet in a temporary buffer, and do not forward it after it has
> been completely received.

OK, will fix in V3

Thanks
zhangchen

> > +    }
> > +
> > +    memcpy(&len, buf, sizeof(len));
> > +    len = ntohl(len);
> > +
> > +    if (len > 0 && len < NET_BUFSIZE) {
> > +        recv_buf = g_malloc(len);
> > +        ret = qemu_chr_fe_read_all(s->chr_in, recv_buf, len);
> > +        if (ret != len) {
> > +            error_report("filter-redirector recv buf failed");
> > +            g_free(recv_buf);
> > +            return;
> > +        }
> > +
> > +        ret = qemu_net_queue_send(s->incoming_queue, nf->netdev,
> > +                            0, (const uint8_t *)recv_buf, len, NULL);
> As I replied in last version. Sender should be chose depending on
> 'queues'. When 'queue=rx' sender should be be netdev's peer.
>
>
>
> .

--
Thanks
zhangchen