Re: [Qemu-devel] [PATCH v3 07/12] netfilter: add an API to pass the packet to next filter

[Jason Wang <jasowang@redhat.com>]

On 08/03/2015 04:30 PM, Yang Hongyang wrote:
> add an API qemu_netfilter_pass_to_next_iov() to pass the packet
> to next filter, and a wrapper qemu_netfilter_pass_to_next().
>
> Signed-off-by: Yang Hongyang <yanghy@cn.fujitsu.com>
> ---
>  include/net/filter.h | 12 ++++++++++++
>  include/net/net.h    |  1 +
>  net/filter.c         | 31 +++++++++++++++++++++++++++++++
>  net/net.c            | 13 +++++++++++++
>  4 files changed, 57 insertions(+)
>
> diff --git a/include/net/filter.h b/include/net/filter.h
> index 7f0c949..c2be970 100644
> --- a/include/net/filter.h
> +++ b/include/net/filter.h
> @@ -53,4 +53,16 @@ void qemu_del_net_filter(NetFilterState *nf);
>  void netfilter_add(QemuOpts *opts, Error **errp);
>  void qmp_netfilter_add(QDict *qdict, QObject **ret, Error **errp);
>  
> +/* pass the packet to the next filter */
> +void qemu_netfilter_pass_to_next_iov(NetFilterState *nf,
> +                                     NetClientState *sender,
> +                                     unsigned flags,
> +                                     const struct iovec *iov,
> +                                     int iovcnt);
> +void qemu_netfilter_pass_to_next(NetFilterState *nf,
> +                                 NetClientState *sender,
> +                                 unsigned flags,
> +                                 const uint8_t *data,
> +                                 size_t size);
> +
>  #endif /* QEMU_NET_FILTER_H */
> diff --git a/include/net/net.h b/include/net/net.h
> index 5c5c109..d3bfe12 100644
> --- a/include/net/net.h
> +++ b/include/net/net.h
> @@ -117,6 +117,7 @@ NetClientState *qemu_new_net_client(NetClientInfo *info,
>                                      const char *name);
>  int qemu_netdev_add_filter(NetClientState *nc, NetFilterState *nf);
>  void qemu_netdev_remove_filter(NetClientState *nc, NetFilterState *nf);
> +NetFilterState *qemu_netdev_next_filter(NetClientState *nc, NetFilterState *nf);
>  NICState *qemu_new_nic(NetClientInfo *info,
>                         NICConf *conf,
>                         const char *model,
> diff --git a/net/filter.c b/net/filter.c
> index bf113e9..84845b1 100644
> --- a/net/filter.c
> +++ b/net/filter.c
> @@ -131,6 +131,37 @@ void qmp_netfilter_del(const char *id, Error **errp)
>      qemu_opts_del(opts);
>  }
>  
> +void qemu_netfilter_pass_to_next_iov(NetFilterState *nf,
> +                                     NetClientState *sender,
> +                                     unsigned flags,
> +                                     const struct iovec *iov,
> +                                     int iovcnt)
> +{
> +    NetFilterState *next = qemu_netdev_next_filter(nf->netdev, nf);
> +
> +    while (next) {
> +        if (next->chain == nf->chain || next->chain == NET_FILTER_ALL) {
> +            next->info->receive_iov(next, sender, flags, iov, iovcnt);

If a packet is not held by one filter, we need pass it to next filter?

> +            return;
> +        }
> +        next = qemu_netdev_next_filter(next->netdev, next);
> +    }

If a packet has gone through all filters, we probably need to pass it
the receiver's incoming queue.

> +}

Looks like no real user for this helper?

> +
> +void qemu_netfilter_pass_to_next(NetFilterState *nf,
> +                                 NetClientState *sender,
> +                                 unsigned flags,
> +                                 const uint8_t *data,
> +                                 size_t size)
> +{
> +    struct iovec iov = {
> +        .iov_base = (void *)data,
> +        .iov_len = size
> +    };
> +
> +    return qemu_netfilter_pass_to_next_iov(nf, sender, flags, &iov, 1);
> +}
> +
>  typedef int (NetFilterInit)(const NetFilterOptions *opts,
>                              const char *name, int chain,
>                              NetClientState *netdev, Error **errp);
> diff --git a/net/net.c b/net/net.c
> index f774c39..e087763 100644
> --- a/net/net.c
> +++ b/net/net.c
> @@ -339,6 +339,19 @@ void qemu_netdev_remove_filter(NetClientState *nc, NetFilterState *nf)
>      remove_filter(nc, filter);
>  }
>  
> +NetFilterState *qemu_netdev_next_filter(NetClientState *nc, NetFilterState *nf)
> +{
> +    Filter *filter = NULL;
> +
> +    QTAILQ_FOREACH(filter, &nc->filters, next) {
> +        if (filter->nf == nf) {
> +            break;
> +        }
> +    }

A little bit confused, can we just use net->next?

> +
> +    return QTAILQ_NEXT(filter, next)->nf;
> +}
> +
>  NICState *qemu_new_nic(NetClientInfo *info,
>                         NICConf *conf,
>                         const char *model,