Re: [Qemu-devel] [PATCH V5 1/2] net/filter-mirror: implement filter-redirector

[Jason Wang]

On 03/16/2016 06:38 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
>
> usage:
>
> -netdev user,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>
> Signed-off-by: Li Zhijian <address@hidden>
> ---
>  net/filter-mirror.c | 245 
> ++++++++++++++++++++++++++++++++++++++++++++++++++++
>  qemu-options.hx     |   9 ++
>  vl.c                |   3 +-
>  3 files changed, 256 insertions(+), 1 deletion(-)
>
> diff --git a/net/filter-mirror.c b/net/filter-mirror.c
> index 1b1ec16..7b47c60 100644
> --- a/net/filter-mirror.c
> +++ b/net/filter-mirror.c
> @@ -26,12 +26,23 @@
>  #define FILTER_MIRROR(obj) \
>      OBJECT_CHECK(MirrorState, (obj), TYPE_FILTER_MIRROR)
>  
> +#define FILTER_REDIRECTOR(obj) \
> +    OBJECT_CHECK(MirrorState, (obj), TYPE_FILTER_REDIRECTOR)
> +
>  #define TYPE_FILTER_MIRROR "filter-mirror"
> +#define TYPE_FILTER_REDIRECTOR "filter-redirector"
> +#define REDIRECTOR_MAX_LEN NET_BUFSIZE
>  
>  typedef struct MirrorState {
>      NetFilterState parent_obj;
> +    char *indev;
>      char *outdev;
> +    CharDriverState *chr_in;
>      CharDriverState *chr_out;
> +    int state; /* 0 = getting length, 1 = getting data */
> +    unsigned int index;
> +    unsigned int packet_len;
> +    uint8_t buf[REDIRECTOR_MAX_LEN];
>  } MirrorState;
>  
>  static int filter_mirror_send(CharDriverState *chr_out,
> @@ -68,6 +79,97 @@ err:
>      return ret < 0 ? ret : -EIO;
>  }
>  
> +static void
> +redirector_to_filter(NetFilterState *nf, const uint8_t *buf, int len)
> +{
> +    struct iovec iov = {
> +        .iov_base = (void *)buf,
> +        .iov_len = len,
> +    };
> +
> +    if (nf->direction == NET_FILTER_DIRECTION_ALL ||
> +        nf->direction == NET_FILTER_DIRECTION_TX) {
> +        qemu_netfilter_pass_to_next(nf->netdev, 0, &iov, 1, nf);
> +    }
> +
> +    if (nf->direction == NET_FILTER_DIRECTION_ALL ||
> +        nf->direction == NET_FILTER_DIRECTION_RX) {
> +        qemu_netfilter_pass_to_next(nf->netdev->peer, 0, &iov, 1, nf);
> +     }
> +}
> +
> +static int redirector_chr_can_read(void *opaque)
> +{
> +    return REDIRECTOR_MAX_LEN;
> +}
> +
> +static void redirector_chr_read(void *opaque, const uint8_t *buf, int size)
> +{
> +    NetFilterState *nf = opaque;
> +    MirrorState *s = FILTER_REDIRECTOR(nf);
> +    unsigned int l;
> +
> +    while (size > 0) {
> +        /* reassemble a packet from the network */
> +        switch (s->state) { /* 0 = getting length, 1 = getting data */
> +        case 0:
> +            l = 4 - s->index;
> +            if (l > size) {
> +                l = size;
> +            }
> +            memcpy(s->buf + s->index, buf, l);
> +            buf += l;
> +            size -= l;
> +            s->index += l;
> +            if (s->index == 4) {
> +                /* got length */
> +                s->packet_len = ntohl(*(uint32_t *)s->buf);
> +                s->index = 0;
> +                s->state = 1;
> +            }
> +            break;
> +        case 1:
> +            l = s->packet_len - s->index;
> +            if (l > size) {
> +                l = size;
> +            }
> +            if (s->index + l <= sizeof(s->buf)) {
> +                memcpy(s->buf + s->index, buf, l);
> +            } else {
> +                error_report("%s, serious error: oversized packet received,"
> +                             "connection terminated.", __func__);

The connection was not terminated actually. And since the warning is
unique, __func__ is probably not necessary.

> +                s->index = s->state = 0;
> +                qemu_chr_add_handlers(s->chr_in, NULL, NULL, NULL, NULL);
> +                return;
> +            }
> +
> +            s->index += l;
> +            buf += l;
> +            size -= l;
> +            if (s->index >= s->packet_len) {
> +                s->index = 0;
> +                s->state = 0;
> +                redirector_to_filter(nf, s->buf, s->packet_len);
> +            }
> +            break;
> +        }
> +    }
> +}
> +
> +static void redirector_chr_event(void *opaque, int event)
> +{
> +    NetFilterState *nf = opaque;
> +    MirrorState *s = FILTER_REDIRECTOR(nf);
> +
> +    switch(event) {
> +    case CHR_EVENT_CLOSED:
> +        qemu_chr_add_handlers(s->chr_in, NULL, NULL, NULL, NULL);
> +        break;
> +    default:
> +        break;
> +    }
> +}
> +
>  static ssize_t filter_mirror_receive_iov(NetFilterState *nf,
>                                           NetClientState *sender,
>                                           unsigned flags,
> @@ -90,6 +192,27 @@ static ssize_t filter_mirror_receive_iov(NetFilterState 
> *nf,
>      return 0;
>  }
>  
> +static ssize_t filter_redirector_receive_iov(NetFilterState *nf,
> +                                         NetClientState *sender,
> +                                         unsigned flags,
> +                                         const struct iovec *iov,
> +                                         int iovcnt,
> +                                         NetPacketSent *sent_cb)
> +{
> +    MirrorState *s = FILTER_REDIRECTOR(nf);
> +    int ret;
> +
> +    if (s->chr_out) {
> +        ret = filter_mirror_send(s->chr_out, iov, iovcnt);
> +        if (ret) {
> +            error_report("filter_mirror_send failed(%s)", strerror(-ret));
> +        }
> +        return iov_size(iov, iovcnt);
> +    } else {
> +        return 0;
> +    }
> +}
> +
>  static void filter_mirror_cleanup(NetFilterState *nf)
>  {
>      MirrorState *s = FILTER_MIRROR(nf);
> @@ -99,6 +222,18 @@ static void filter_mirror_cleanup(NetFilterState *nf)
>      }
>  }
>  
> +static void filter_redirector_cleanup(NetFilterState *nf)
> +{
> +    MirrorState *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 void filter_mirror_setup(NetFilterState *nf, Error **errp)
>  {
>      MirrorState *s = FILTER_MIRROR(nf);
> @@ -122,6 +257,48 @@ static void filter_mirror_setup(NetFilterState *nf, 
> Error **errp)
>      }
>  }
>  
> +static void filter_redirector_setup(NetFilterState *nf, Error **errp)
> +{
> +    MirrorState *s = FILTER_REDIRECTOR(nf);
> +
> +    if (!s->indev && !s->outdev) {
> +        error_setg(errp, "filter redirector needs 'indev' or "
> +                "'outdev' at least one property set");

Please fix the indentation here.

> +        return;
> +    } else if (s->indev && s->outdev) {
> +        if (!strcmp(s->indev, s->outdev)) {
> +            error_setg(errp, "filter redirector needs 'indev' and "
> +                    "'outdev'  are not same");

and here. And maybe "'indev' and 'outdev' could not be same for filter
redirector" is better here.

> +            return;
> +        }
> +    }
> +
> +    s->state = s->index = 0;
> +
> +    if (s->indev) {
> +        s->chr_in = qemu_chr_find(s->indev);
> +        if (s->chr_in == NULL) {
> +            error_set(errp, ERROR_CLASS_DEVICE_NOT_FOUND,
> +                      "IN Device '%s' not found", s->indev);
> +            return;
> +        }
> +
> +        qemu_chr_fe_claim_no_fail(s->chr_in);
> +        qemu_chr_add_handlers(s->chr_in, redirector_chr_can_read,
> +                              redirector_chr_read, redirector_chr_event, nf);
> +    }
> +
> +    if (s->outdev) {
> +        s->chr_out = qemu_chr_find(s->outdev);
> +        if (s->chr_out == NULL) {
> +            error_set(errp, ERROR_CLASS_DEVICE_NOT_FOUND,
> +                      "OUT Device '%s' not found", s->outdev);
> +            return;
> +        }
> +        qemu_chr_fe_claim_no_fail(s->chr_out);
> +    }
> +}
> +
>  static void filter_mirror_class_init(ObjectClass *oc, void *data)
>  {
>      NetFilterClass *nfc = NETFILTER_CLASS(oc);
> @@ -131,6 +308,31 @@ static void filter_mirror_class_init(ObjectClass *oc, 
> void *data)
>      nfc->receive_iov = filter_mirror_receive_iov;
>  }
>  
> +static void filter_redirector_class_init(ObjectClass *oc, void *data)
> +{
> +    NetFilterClass *nfc = NETFILTER_CLASS(oc);
> +
> +    nfc->setup = filter_redirector_setup;
> +    nfc->cleanup = filter_redirector_cleanup;
> +    nfc->receive_iov = filter_redirector_receive_iov;
> +}
> +
> +static char *filter_redirector_get_indev(Object *obj, Error **errp)
> +{
> +    MirrorState *s = FILTER_REDIRECTOR(obj);
> +
> +    return g_strdup(s->indev);
> +}
> +
> +static void
> +filter_redirector_set_indev(Object *obj, const char *value, Error **errp)
> +{
> +    MirrorState *s = FILTER_REDIRECTOR(obj);
> +
> +    g_free(s->indev);
> +    s->indev = g_strdup(value);
> +}
> +
>  static char *filter_mirror_get_outdev(Object *obj, Error **errp)
>  {
>      MirrorState *s = FILTER_MIRROR(obj);
> @@ -152,12 +354,36 @@ filter_mirror_set_outdev(Object *obj, const char 
> *value, Error **errp)
>      }
>  }
>  
> +static char *filter_redirector_get_outdev(Object *obj, Error **errp)
> +{
> +    MirrorState *s = FILTER_REDIRECTOR(obj);
> +
> +    return g_strdup(s->outdev);
> +}
> +
> +static void
> +filter_redirector_set_outdev(Object *obj, const char *value, Error **errp)
> +{
> +    MirrorState *s = FILTER_REDIRECTOR(obj);
> +
> +    g_free(s->outdev);
> +    s->outdev = g_strdup(value);
> +}
> +
>  static void filter_mirror_init(Object *obj)
>  {
>      object_property_add_str(obj, "outdev", filter_mirror_get_outdev,
>                              filter_mirror_set_outdev, NULL);
>  }
>  
> +static void filter_redirector_init(Object *obj)
> +{
> +    object_property_add_str(obj, "indev", filter_redirector_get_indev,
> +                            filter_redirector_set_indev, NULL);
> +    object_property_add_str(obj, "outdev", filter_redirector_get_outdev,
> +                            filter_redirector_set_outdev, NULL);
> +}
> +
>  static void filter_mirror_fini(Object *obj)
>  {
>      MirrorState *s = FILTER_MIRROR(obj);
> @@ -165,6 +391,24 @@ static void filter_mirror_fini(Object *obj)
>      g_free(s->outdev);
>  }
>  
> +static void filter_redirector_fini(Object *obj)
> +{
> +    MirrorState *s = FILTER_REDIRECTOR(obj);
> +
> +    qemu_chr_add_handlers(s->chr_in, NULL, NULL, NULL, NULL);
> +    g_free(s->indev);
> +    g_free(s->outdev);
> +}
> +
> +static const TypeInfo filter_redirector_info = {
> +    .name = TYPE_FILTER_REDIRECTOR,
> +    .parent = TYPE_NETFILTER,
> +    .class_init = filter_redirector_class_init,
> +    .instance_init = filter_redirector_init,
> +    .instance_finalize = filter_redirector_fini,
> +    .instance_size = sizeof(MirrorState),
> +};
> +
>  static const TypeInfo filter_mirror_info = {
>      .name = TYPE_FILTER_MIRROR,
>      .parent = TYPE_NETFILTER,
> @@ -177,6 +421,7 @@ static const TypeInfo filter_mirror_info = {
>  static void register_types(void)
>  {
>      type_register_static(&filter_mirror_info);
> +    type_register_static(&filter_redirector_info);
>  }
>  
>  type_init(register_types);
> diff --git a/qemu-options.hx b/qemu-options.hx
> index 5379cb5..796d053 100644
> --- a/qemu-options.hx
> +++ b/qemu-options.hx
> @@ -3821,6 +3821,15 @@ queue @var{all|rx|tx} is an option that can be applied 
> to any netfilter.
>  filter-mirror on netdev @var{netdevid},mirror net packet to chardev
>  @var{chardevid}
>  
> address@hidden -object 
> filter-redirector,address@hidden,address@hidden,address@hidden,
> address@hidden,address@hidden|rx|tx}]
> +
> +filter-redirector on netdev @var{netdevid},redirect filter's net packet to 
> chardev
> address@hidden,and redirect indev's packet to filter.
> +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-dump,address@hidden,address@hidden,address@hidden,address@hidden
>  
>  Dump the network traffic on netdev @var{dev} to the file specified by
> diff --git a/vl.c b/vl.c
> index 79bb11a..dc6e63a 100644
> --- a/vl.c
> +++ b/vl.c
> @@ -2841,7 +2841,8 @@ static bool object_create_initial(const char *type)
>       */
>      if (g_str_equal(type, "filter-buffer") ||
>          g_str_equal(type, "filter-dump") ||
> -        g_str_equal(type, "filter-mirror")) {
> +        g_str_equal(type, "filter-mirror") ||
> +        g_str_equal(type, "filter-redirector")) {
>          return false;
>      }
>