Re: [Qemu-devel] [PATCH v10 06/10] netfilter: add an API to pass the packet to next filter

[Jason Wang <jasowang@redhat.com>]

On 09/09/2015 03:24 PM, Yang Hongyang wrote:
> add an API qemu_netfilter_pass_to_next() to pass the packet
> to next filter.
>
> Signed-off-by: Yang Hongyang <yanghy@cn.fujitsu.com>
> Reviewed-by: Thomas Huth <thuth@redhat.com>
> ---
> v10: adjust as a NetQueueDeliverFunc
> v9: fix a bug when curr filter chain is all
> v5: fold params to NetPacket struct
> ---
>  include/net/filter.h |  7 ++++++
>  net/filter.c         | 60 ++++++++++++++++++++++++++++++++++++++++++++++++++++
>  2 files changed, 67 insertions(+)
>
> diff --git a/include/net/filter.h b/include/net/filter.h
> index 4557cb9..ed2bb66 100644
> --- a/include/net/filter.h
> +++ b/include/net/filter.h
> @@ -57,4 +57,11 @@ struct NetFilterState {
>      QTAILQ_ENTRY(NetFilterState) next;
>  };
>  
> +/* pass the packet to the next filter */
> +ssize_t qemu_netfilter_pass_to_next(NetClientState *sender,
> +                                    unsigned flags,
> +                                    const struct iovec *iov,
> +                                    int iovcnt,
> +                                    void *opaque);
> +
>  #endif /* QEMU_NET_FILTER_H */
> diff --git a/net/filter.c b/net/filter.c
> index 5192c6d..086f271 100644
> --- a/net/filter.c
> +++ b/net/filter.c
> @@ -14,9 +14,69 @@
>  #include "net/net.h"
>  #include "net/vhost_net.h"
>  #include "qom/object_interfaces.h"
> +#include "qemu/iov.h"
>  
>  static QTAILQ_HEAD(, NetFilterState) net_filters;
>  
> +ssize_t qemu_netfilter_pass_to_next(NetClientState *sender,
> +                                    unsigned flags,
> +                                    const struct iovec *iov,
> +                                    int iovcnt,
> +                                    void *opaque)
> +{
> +    int ret = 0;
> +    int chain;
> +    NetFilterState *nf = opaque;
> +    NetFilterState *next = QTAILQ_NEXT(nf, next);
> +
> +    if (!sender || !sender->peer) {
> +        /* no receiver, or sender been deleted, no need to pass it further */
> +        goto out;
> +    }
> +
> +    if (nf->chain == NET_FILTER_CHAIN_ALL) {
> +        if (sender == nf->netdev) {
> +            /* This packet is sent by netdev itself */
> +            chain = NET_FILTER_CHAIN_OUT;
> +        } else {
> +            chain = NET_FILTER_CHAIN_IN;
> +        }
> +    } else {
> +        chain = nf->chain;
> +    }
> +
> +    while (next) {
> +        if (next->chain == chain || next->chain == NET_FILTER_CHAIN_ALL) {
> +            /*
> +             * if qemu_netfilter_pass_to_next been called, means that
> +             * the packet has been hold by filter and has already retured size
> +             * to the sender, so sent_cb shouldn't be called later, just
> +             * pass NULL to next.
> +             */
> +            ret = NETFILTER_GET_CLASS(OBJECT(next))->receive_iov(
> +                                    next, sender, flags, iov, iovcnt, NULL);
> +            if (ret) {
> +                return ret;
> +            }
> +        }
> +        next = QTAILQ_NEXT(next, next);
> +    }

Nitpick:

Kind of codes duplication with filter_receive(). May consider to unify
them it you want to send next version.

> +
> +    /*
> +     * We have gone through all filters, pass it to receiver.
> +     * Do the valid check again incase sender or receiver been
> +     * deleted while we go through filters.
> +     */
> +    if (sender && sender->peer) {
> +        return qemu_net_queue_send_iov(sender->peer->incoming_queue,
> +                                       sender, flags, iov, iovcnt, NULL);
> +    }
> +
> +out:
> +    /* no receiver, or sender been deleted */
> +    return iov_size(iov, iovcnt);
> +}
> +
>  static char *netfilter_get_netdev_id(Object *obj, Error **errp)
>  {
>      NetFilterState *nf = NETFILTER(obj);