net: stream: add a new option to automatically reconnect

In stream mode, if the server shuts down there is currently
no way to reconnect the client to a new server without removing
the NIC device and the netdev backend (or to reboot).

This patch introduces a reconnect option that specifies a delay
to try to reconnect with the same parameters.

Add a new test in qtest to test the reconnect option and the
connect/disconnect events.

Signed-off-by: Laurent Vivier <lvivier@redhat.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>

1 files changed, 52 insertions, 1 deletions

diff --git a/net/stream.c b/net/stream.c
index 37ff727e0c..9204b4c96e 100644
--- a/net/stream.c
+++ b/net/stream.c
@@ -39,6 +39,8 @@
 #include "io/channel-socket.h"
 #include "io/net-listener.h"
 #include "qapi/qapi-events-net.h"
+#include "qapi/qapi-visit-sockets.h"
+#include "qapi/clone-visitor.h"
 
 typedef struct NetStreamState {
     NetClientState nc;
@@ -49,11 +51,15 @@ typedef struct NetStreamState {
     guint ioc_write_tag;
     SocketReadState rs;
     unsigned int send_index;      /* number of bytes sent*/
+    uint32_t reconnect;
+    guint timer_tag;
+    SocketAddress *addr;
 } NetStreamState;
 
 static void net_stream_listen(QIONetListener *listener,
                               QIOChannelSocket *cioc,
                               void *opaque);
+static void net_stream_arm_reconnect(NetStreamState *s);
 
 static gboolean net_stream_writable(QIOChannel *ioc,
                                     GIOCondition condition,
@@ -170,6 +176,7 @@ static gboolean net_stream_send(QIOChannel *ioc,
         qemu_set_info_str(&s->nc, "%s", "");
 
         qapi_event_send_netdev_stream_disconnected(s->nc.name);
+        net_stream_arm_reconnect(s);
 
         return G_SOURCE_REMOVE;
     }
@@ -187,6 +194,14 @@ static gboolean net_stream_send(QIOChannel *ioc,
 static void net_stream_cleanup(NetClientState *nc)
 {
     NetStreamState *s = DO_UPCAST(NetStreamState, nc, nc);
+    if (s->timer_tag) {
+        g_source_remove(s->timer_tag);
+        s->timer_tag = 0;
+    }
+    if (s->addr) {
+        qapi_free_SocketAddress(s->addr);
+        s->addr = NULL;
+    }
     if (s->ioc) {
         if (QIO_CHANNEL_SOCKET(s->ioc)->fd != -1) {
             if (s->ioc_read_tag) {
@@ -346,12 +361,37 @@ static void net_stream_client_connected(QIOTask *task, gpointer opaque)
 error:
     object_unref(OBJECT(s->ioc));
     s->ioc = NULL;
+    net_stream_arm_reconnect(s);
+}
+
+static gboolean net_stream_reconnect(gpointer data)
+{
+    NetStreamState *s = data;
+    QIOChannelSocket *sioc;
+
+    s->timer_tag = 0;
+
+    sioc = qio_channel_socket_new();
+    s->ioc = QIO_CHANNEL(sioc);
+    qio_channel_socket_connect_async(sioc, s->addr,
+                                     net_stream_client_connected, s,
+                                     NULL, NULL);
+    return G_SOURCE_REMOVE;
+}
+
+static void net_stream_arm_reconnect(NetStreamState *s)
+{
+    if (s->reconnect && s->timer_tag == 0) {
+        s->timer_tag = g_timeout_add_seconds(s->reconnect,
+                                             net_stream_reconnect, s);
+    }
 }
 
 static int net_stream_client_init(NetClientState *peer,
                                   const char *model,
                                   const char *name,
                                   SocketAddress *addr,
+                                  uint32_t reconnect,
                                   Error **errp)
 {
     NetStreamState *s;
@@ -364,6 +404,10 @@ static int net_stream_client_init(NetClientState *peer,
     s->ioc = QIO_CHANNEL(sioc);
     s->nc.link_down = true;
 
+    s->reconnect = reconnect;
+    if (reconnect) {
+        s->addr = QAPI_CLONE(SocketAddress, addr);
+    }
     qio_channel_socket_connect_async(sioc, addr,
                                      net_stream_client_connected, s,
                                      NULL, NULL);
@@ -380,7 +424,14 @@ int net_init_stream(const Netdev *netdev, const char *name,
     sock = &netdev->u.stream;
 
     if (!sock->has_server || !sock->server) {
-        return net_stream_client_init(peer, "stream", name, sock->addr, errp);
+        return net_stream_client_init(peer, "stream", name, sock->addr,
+                                      sock->has_reconnect ? sock->reconnect : 0,
+                                      errp);
+    }
+    if (sock->has_reconnect) {
+        error_setg(errp, "'reconnect' option is incompatible with "
+                         "socket in server mode");
+        return -1;
     }
     return net_stream_server_init(peer, "stream", name, sock->addr, errp);
 }