Re: [Qemu-devel] [PATCH v2 2/2] net: introduce command to query mac-table information

[Stefan Hajnoczi]

On Thu, May 16, 2013 at 07:07:25PM +0800, Amos Kong wrote:
> @@ -961,6 +961,44 @@ void print_net_client(Monitor *mon, NetClientState *nc)
>                     nc->info_str);
>  }
>  
> +MacTableInfoList *qmp_query_mac_table(bool has_name, const char *name,
> +                                      Error **errp)
> +{
> +    NetClientState *nc;
> +    MacTableInfoList *table_list = NULL, *last_entry = NULL;
> +
> +    QTAILQ_FOREACH(nc, &net_clients, next) {
> +        MacTableInfoList *entry;
> +        MacTableInfo *info;
> +
> +        if (nc->info->type != NET_CLIENT_OPTIONS_KIND_NIC) {
> +            continue;
> +        }
> +        if (has_name && strcmp(nc->name, name) != 0) {
> +            continue;
> +        }
> +
> +        if (nc->info->query_mac_table) {
> +            info = nc->info->query_mac_table(nc);
> +            entry = g_malloc0(sizeof(*entry));
> +            entry->value = info;
> +
> +            if (!table_list) {
> +                table_list = entry;
> +            } else {
> +                last_entry->next = entry;
> +            }
> +            last_entry = entry;
> +        }
> +    }
> +
> +    if (table_list == NULL) {
> +        error_setg(errp, "invalid net client name: %s", name);
> +    }

Produces confusing errors:

1. If query-mac-table is used without a name argument and the guest has
   no NIC or no NICs support ->query_mac_table().

2. If the named NIC does not support ->query_mac_table().