Re: [PATCH v11 17/17] net: stream: add QAPI events to report connection state

[Laurent Vivier]

On 10/17/22 15:23, Markus Armbruster wrote:
> Laurent Vivier <lvivier@redhat.com> writes:
>
> > The netdev reports NETDEV_STREAM_CONNECTED event when the backend
> > is connected, and NETDEV_STREAM_EOC when it is disconnected.
> >
> > The NETDEV_STREAM_CONNECTED event includes the URI of the destination
> > address.
> >
> > Signed-off-by: Laurent Vivier <lvivier@redhat.com>
> > Acked-by: Michael S. Tsirkin <mst@redhat.com>
> > ---
> >   net/stream.c  | 11 +++++++++--
> >   qapi/net.json | 46 ++++++++++++++++++++++++++++++++++++++++++++++
> >   2 files changed, 55 insertions(+), 2 deletions(-)
> >
> > diff --git a/net/stream.c b/net/stream.c
> > index 0293e38e5b57..821ae3265356 100644
> > --- a/net/stream.c
> > +++ b/net/stream.c
> > @@ -38,6 +38,7 @@
> >   #include "io/channel.h"
> >   #include "io/channel-socket.h"
> >   #include "io/net-listener.h"
> > +#include "qapi/qapi-events-net.h"
> >   
> >   typedef struct NetStreamState {
> >       NetClientState nc;
> > @@ -168,6 +169,8 @@ static gboolean net_stream_send(QIOChannel *ioc,
> >           s->nc.link_down = true;
> >           qemu_set_info_str(&s->nc, "");
> >   
> > +        qapi_event_send_netdev_stream_eoc(s->nc.name);
> > +
> >           return G_SOURCE_REMOVE;
> >       }
> >       buf = buf1;
> > @@ -243,9 +246,10 @@ static void net_stream_listen(QIONetListener *listener,
> >       g_assert(addr != NULL);
> >       uri = socket_uri(addr);
> >       qemu_set_info_str(&s->nc, uri);
> > -    g_free(uri);
> >       qapi_free_SocketAddress(addr);
> >   
> > +    qapi_event_send_netdev_stream_connected(s->nc.name, uri);
> > +    g_free(uri);
> >   }
> >   
> >   static void net_stream_server_listening(QIOTask *task, gpointer opaque)
> > @@ -317,12 +321,12 @@ static void net_stream_client_connected(QIOTask *task, 
> > gpointer opaque)
> >       g_assert(addr != NULL);
> >       uri = socket_uri(addr);
> >       qemu_set_info_str(&s->nc, uri);
> > -    g_free(uri);
> >   
> >       ret = qemu_socket_try_set_nonblock(sioc->fd);
> >       if (addr->type == SOCKET_ADDRESS_TYPE_FD && ret < 0) {
> >           qemu_set_info_str(&s->nc, "can't use file descriptor %s (errno %d)",
> >                             addr->u.fd.str, -ret);
> > +        g_free(uri);
> >           qapi_free_SocketAddress(addr);
> >           goto error;
> >       }
> > @@ -338,6 +342,9 @@ static void net_stream_client_connected(QIOTask *task, 
> > gpointer opaque)
> >                                               s, NULL);
> >       s->nc.link_down = false;
> >   
> > +    qapi_event_send_netdev_stream_connected(s->nc.name, uri);
> > +    g_free(uri);
> > +
> >       return;
> >   error:
> >       object_unref(OBJECT(s->ioc));
> > diff --git a/qapi/net.json b/qapi/net.json
> > index 6a1a49749294..69f83bceff3f 100644
> > --- a/qapi/net.json
> > +++ b/qapi/net.json
> > @@ -895,3 +895,49 @@
> >   ##
> >   { 'event': 'FAILOVER_NEGOTIATED',
> >     'data': {'device-id': 'str'} }
> > +
> > +##
> > +# @NETDEV_STREAM_CONNECTED:
> > +#
> > +# Emitted when the netdev stream backend is connected
> > +#
> > +# @netdev-id: QEMU netdev id that is connected
> > +# @uri: The Uniform Resource Identifier identifying the destination address
>
> Is an URI the appropriate representation here?  It's not how we specify
> such addresses elsewhere in QAPI/QMP...

I put in the event the same information we have in info_str and displayed by the HMP 
command 'info network'. What would be a more appropriate reprensation?

> > +#
> > +# Since: 7.2
> > +#
> > +# Example:
> > +#
> > +# <- { 'event': 'NETDEV_STREAM_CONNECTED',
> > +#      'data': {'uri': 'tcp:::1:1234', 'netdev-id': 'netdev0'},
> > +#      'timestamp': {'seconds': 1663330564, 'microseconds': 804317} }
> > +#
> > +# or
> > +#
> > +# <- { 'event': 'NETDEV_STREAM_CONNECTED',
> > +#      'data': {'uri': ''unix:/tmp/qemu0', 'netdev-id': 'netdev0'},
> > +#      'timestamp': {'seconds': 1663330564, 'microseconds': 804317} }
> > +#
> > +##
> > +{ 'event': 'NETDEV_STREAM_CONNECTED',
> > +  'data': { 'netdev-id': 'str',
> > +            'uri': 'str' } }
> > +
> > +##
> > +# @NETDEV_STREAM_EOC:
>
> What does "EOC" mean?

End-Of-Connection, this is the nomenclature used in the code when the socket is 
disconnected.
> Could this be named NETDEV_STREAM_DISCONNECTED, for symmetry with
> NETDEV_STREAM_CONNECTED?

Yes, it can. EOC is shorter, it's why I used it, but if you prefer 
"disconnected"...

Thanks,
Laurent

> > +#
> > +# Emitted when the netdev stream backend is disconnected
> > +#
> > +# @netdev-id: QEMU netdev id that is disconnected
> > +#
> > +# Since: 7.2
> > +#
> > +# Example:
> > +#
> > +# <- { 'event': 'NETDEV_STREAM_EOC',
> > +#      'data': {'netdev-id': 'netdev0'},
> > +#      'timestamp': {'seconds': 1663330937, 'microseconds': 526695} }
> > +#
> > +##
> > +{ 'event': 'NETDEV_STREAM_EOC',
> > +  'data': { 'netdev-id': 'str' } }