[PATCH v3 10/49] net/qapi: add x-query-usernet command

Add a QMP command to query user-mode network stack (slirp) connection
states, providing a structured alternative to "info usernet" HMP.

The new command returns a list of UsernetInfo, with hub-id, hub-name,
and connection info for each slirp stack. It is marked unstable as it
is meant for debugging.

Rewrite hmp_info_usernet() as a thin wrapper over qmp_x_query_usernet()
so the HMP and QMP paths share the same implementation.

This is part of the effort to decouple HMP from QEMU core.

Reviewed-by: Daniel P. Berrangé <[email protected]>
Signed-off-by: Marc-Andre Lureau <[email protected]>
---
 net/slirp.c   | 34 ++++++++++++++++++++++++++++------
 qapi/net.json | 44 ++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 72 insertions(+), 6 deletions(-)

diff --git a/net/slirp.c b/net/slirp.c
index 9e9941fe73e7..517dd23be14b 100644
--- a/net/slirp.c
+++ b/net/slirp.c
@@ -43,6 +43,7 @@
 #include "system/system.h"
 #include "qemu/cutils.h"
 #include "qapi/error.h"
+#include "qapi/qapi-commands-net.h"
 #include "qobject/qdict.h"
 #include "util.h"
 #include "migration/register.h"
@@ -1200,18 +1201,39 @@ static int slirp_guestfwd(SlirpState *s, const char *config_str, Error **errp)
     return -1;
 }
 
-void hmp_info_usernet(Monitor *mon, const QDict *qdict)
+UsernetInfoList *qmp_x_query_usernet(Error **errp)
 {
+    UsernetInfoList *head = NULL, **tail = &head;
     SlirpState *s;
 
     QTAILQ_FOREACH(s, &slirp_stacks, entry) {
+        UsernetInfo *ui = g_new0(UsernetInfo, 1);
         int id;
-        bool got_hub_id = net_hub_id_for_client(&s->nc, &id) == 0;
-        char *info = slirp_connection_info(s->slirp);
+
+        if (net_hub_id_for_client(&s->nc, &id) == 0) {
+            ui->has_hub_id = true;
+            ui->hub_id = id;
+        }
+        ui->hub_name = g_strdup(s->nc.name);
+        ui->info = slirp_connection_info(s->slirp);
+
+        QAPI_LIST_APPEND(tail, ui);
+    }
+
+    return head;
+}
+
+void hmp_info_usernet(Monitor *mon, const QDict *qdict)
+{
+    g_autoptr(UsernetInfoList) list = NULL;
+    UsernetInfoList *entry;
+
+    list = qmp_x_query_usernet(&error_abort);
+    for (entry = list; entry; entry = entry->next) {
+        UsernetInfo *ui = entry->value;
         monitor_printf(mon, "Hub %d (%s):\n%s",
-                       got_hub_id ? id : -1,
-                       s->nc.name, info);
-        g_free(info);
+                       ui->has_hub_id ? (int)ui->hub_id : -1,
+                       ui->hub_name, ui->info);
     }
 }
 
diff --git a/qapi/net.json b/qapi/net.json
index 1a6382825c5e..5d3342fba23b 100644
--- a/qapi/net.json
+++ b/qapi/net.json
@@ -1261,3 +1261,47 @@
 ##
 { 'event': 'NETDEV_VHOST_USER_DISCONNECTED',
   'data': { 'netdev-id': 'str' } }
+
+##
+# @UsernetInfo:
+#
+# Information about a user-mode network stack (slirp).
+#
+# @hub-id: The hub id, if available.
+#
+# @hub-name: The name of the hub.
+#
+# @info: Network information from slirp.
+#
+# Since: 11.2
+##
+{ 'struct': 'UsernetInfo',
+  'data': {
+    '*hub-id': 'int',
+    'hub-name': 'str',
+    'info': 'str' },
+  'if': 'CONFIG_SLIRP' }
+
+##
+# @x-query-usernet:
+#
+# Query user-mode network stack connection states.
+#
+# Features:
+#
+# @unstable: This command is meant for debugging.
+#
+# Returns: list of user-mode network stack information.
+#
+# Since: 11.2
+#
+# .. qmp-example::
+#
+#     -> { "execute": "x-query-usernet" }
+#     <- { "return": [ { "hub-id": 0, "hub-name": "vnet",
+#                        "info": "..." } ] }
+##
+{ 'command': 'x-query-usernet',
+  'returns': ['UsernetInfo'],
+  'if': 'CONFIG_SLIRP',
+  'features': [ 'unstable' ] }

-- 
2.55.0.543.g5ebe2ebe4ea8