net: add explicit info about connecting/listening state

When running 'info network', if the stream backend is still in
the process of connecting, or waiting for an incoming connection,
no information is displayed.

There is also no way to distinguish whether the server is still
in the process of setting up the listener socket, or whether it
is ready to accept incoming client connections.

This leads to a race condition in the netdev-socket qtest which
launches a server process followed by a client process. Under
high load conditions it is possible for the client to attempt
to connect before the server is accepting clients. For the
scenarios which do not set the 'reconnect' option, this opens
up a race which can lead to the test scenario failing to reach
the expected state.

Now that 'info network' can distinguish between initialization
phase and the listening phase, the netdev-socket qtest will
correctly synchronize, such that the client QEMU is not spawned
until the server is ready.

This should solve the non-deterministic failures seen with the
netdev-socket qtest.

Signed-off-by: "Daniel P. Berrangé" <berrange@redhat.com>
Message-ID: <20240104162942.211458-5-berrange@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Thomas Huth <thuth@redhat.com>

1 files changed, 4 insertions, 1 deletions

diff --git a/net/stream.c b/net/stream.c
index 9204b4c..0defb21 100644
--- a/net/stream.c
+++ b/net/stream.c
@@ -173,7 +173,7 @@ static gboolean net_stream_send(QIOChannel *ioc,
 
         net_socket_rs_init(&s->rs, net_stream_rs_finalize, false);
         s->nc.link_down = true;
-        qemu_set_info_str(&s->nc, "%s", "");
+        qemu_set_info_str(&s->nc, "listening");
 
         qapi_event_send_netdev_stream_disconnected(s->nc.name);
         net_stream_arm_reconnect(s);
@@ -292,6 +292,7 @@ static void net_stream_server_listening(QIOTask *task, gpointer opaque)
     s->nc.link_down = true;
     s->listener = qio_net_listener_new();
 
+    qemu_set_info_str(&s->nc, "listening");
     net_socket_rs_init(&s->rs, net_stream_rs_finalize, false);
     qio_net_listener_set_client_func(s->listener, net_stream_listen, s, NULL);
     qio_net_listener_add(s->listener, listen_sioc);
@@ -309,6 +310,7 @@ static int net_stream_server_init(NetClientState *peer,
 
     nc = qemu_new_net_client(&net_stream_info, peer, model, name);
     s = DO_UPCAST(NetStreamState, nc, nc);
+    qemu_set_info_str(&s->nc, "initializing");
 
     s->listen_ioc = QIO_CHANNEL(listen_sioc);
     qio_channel_socket_listen_async(listen_sioc, addr, 0,
@@ -400,6 +402,7 @@ static int net_stream_client_init(NetClientState *peer,
 
     nc = qemu_new_net_client(&net_stream_info, peer, model, name);
     s = DO_UPCAST(NetStreamState, nc, nc);
+    qemu_set_info_str(&s->nc, "connecting");
 
     s->ioc = QIO_CHANNEL(sioc);
     s->nc.link_down = true;