Re: [Qemu-devel] [PATCH v6 4/8] migration: Create x-socket-address parameter

["Daniel P. Berrangé" <berrange@redhat.com>]

On Wed, Mar 14, 2018 at 05:38:34PM +0100, Juan Quintela wrote:
> It will be used to store the uri parameter. We want this only for tcp,
> so we don't set it for other uris.  We need it to know what port is
> migration running.
> 
> Signed-off-by: Juan Quintela <quintela@redhat.com>
> 
> --
> 
> This used to be uri parameter, but it has so many troubles to
> reproduce that it don't just make sense.
> 
> This used to be a port parameter.  I was asked to move to
> SocketAddress, done.
> I also merged the setting of the migration tcp port in this one
> because now I need to free the address, and this makes it easier.
> ---
>  hmp.c                 |  6 ++++++
>  migration/migration.c | 18 ++++++++++++++++++
>  migration/migration.h |  2 ++
>  migration/socket.c    | 27 ++++++++++++++++++++++-----
>  qapi/migration.json   | 14 ++++++++++++--
>  5 files changed, 60 insertions(+), 7 deletions(-)
> 
> diff --git a/hmp.c b/hmp.c
> index ba9e299ee2..eee84cfd5f 100644
> --- a/hmp.c
> +++ b/hmp.c
> @@ -355,6 +355,12 @@ void hmp_info_migrate_parameters(Monitor *mon, const QDict *qdict)
>          monitor_printf(mon, "%s: %" PRIu64 "\n",
>              MigrationParameter_str(MIGRATION_PARAMETER_XBZRLE_CACHE_SIZE),
>              params->xbzrle_cache_size);
> +        if (params->has_x_socket_address) {
> +            monitor_printf(mon, "%s: %s\n",
> +                MigrationParameter_str(MIGRATION_PARAMETER_X_SOCKET_ADDRESS),
> +                SocketAddress_to_str("", params->x_socket_address,
> +                                     false, false));
> +        }
>      }
>  
>      qapi_free_MigrationParameters(params);
> diff --git a/migration/migration.c b/migration/migration.c
> index 6a4780ef6f..3b811c213a 100644
> --- a/migration/migration.c
> +++ b/migration/migration.c
> @@ -31,6 +31,8 @@
>  #include "migration/vmstate.h"
>  #include "block/block.h"
>  #include "qapi/error.h"
> +#include "qapi/clone-visitor.h"
> +#include "qapi/qapi-visit-sockets.h"
>  #include "qapi/qapi-commands-migration.h"
>  #include "qapi/qapi-events-migration.h"
>  #include "qapi/qmp/qerror.h"
> @@ -268,6 +270,14 @@ int migrate_send_rp_req_pages(MigrationIncomingState *mis, const char *rbname,
>      return migrate_send_rp_message(mis, msg_type, msglen, bufc);
>  }
>  
> +void migrate_set_address(SocketAddress *address)
> +{
> +    MigrationState *s = migrate_get_current();
> +
> +    s->parameters.has_x_socket_address = true;
> +    s->parameters.x_socket_address = address;
> +}
> +
>  void qemu_start_incoming_migration(const char *uri, Error **errp)
>  {
>      const char *p;
> @@ -545,6 +555,11 @@ MigrationParameters *qmp_query_migrate_parameters(Error **errp)
>      params->x_multifd_page_count = s->parameters.x_multifd_page_count;
>      params->has_xbzrle_cache_size = true;
>      params->xbzrle_cache_size = s->parameters.xbzrle_cache_size;
> +    if (s->parameters.x_socket_address) {
> +        params->has_x_socket_address = true;
> +        params->x_socket_address = QAPI_CLONE(SocketAddress,
> +                                              s->parameters.x_socket_address);
> +    }
>  
>      return params;
>  }
> @@ -2542,6 +2557,9 @@ static void migration_instance_finalize(Object *obj)
>      qemu_mutex_destroy(&ms->error_mutex);
>      g_free(params->tls_hostname);
>      g_free(params->tls_creds);
> +    if (params->x_socket_address) {
> +        qapi_free_SocketAddress(params->x_socket_address);
> +    }
>      qemu_sem_destroy(&ms->pause_sem);
>      error_free(ms->error);
>  }
> diff --git a/migration/migration.h b/migration/migration.h
> index 08c5d2ded1..36b9c70fd6 100644
> --- a/migration/migration.h
> +++ b/migration/migration.h
> @@ -234,4 +234,6 @@ void migrate_send_rp_pong(MigrationIncomingState *mis,
>  int migrate_send_rp_req_pages(MigrationIncomingState *mis, const char* rbname,
>                                ram_addr_t start, size_t len);
>  
> +void migrate_set_address(SocketAddress *address);
> +
>  #endif
> diff --git a/migration/socket.c b/migration/socket.c
> index 8a93fb1af5..52db0c0c09 100644
> --- a/migration/socket.c
> +++ b/migration/socket.c
> @@ -15,6 +15,7 @@
>   */
>  
>  #include "qemu/osdep.h"
> +#include "qemu/cutils.h"
>  
>  #include "qemu-common.h"
>  #include "qemu/error-report.h"
> @@ -161,17 +162,24 @@ out:
>  }
>  
>  
> -static void socket_start_incoming_migration(SocketAddress *saddr,
> -                                            Error **errp)
> +static SocketAddress *socket_start_incoming_migration(SocketAddress *saddr,
> +                                                      Error **errp)
>  {
>      QIOChannelSocket *listen_ioc = qio_channel_socket_new();
> +    SocketAddress *address;
>  
>      qio_channel_set_name(QIO_CHANNEL(listen_ioc),
>                           "migration-socket-listener");
>  
>      if (qio_channel_socket_listen_sync(listen_ioc, saddr, errp) < 0) {
>          object_unref(OBJECT(listen_ioc));
> -        return;
> +        return NULL;
> +    }
> +
> +    address = qio_channel_socket_get_local_address(listen_ioc, errp);
> +    if (address < 0) {
> +        object_unref(OBJECT(listen_ioc));
> +        return NULL;
>      }
>  
>      qio_channel_add_watch(QIO_CHANNEL(listen_ioc),
> @@ -179,14 +187,20 @@ static void socket_start_incoming_migration(SocketAddress *saddr,
>                            socket_accept_incoming_migration,
>                            listen_ioc,
>                            (GDestroyNotify)object_unref);
> +    return address;
>  }
>  
>  void tcp_start_incoming_migration(const char *host_port, Error **errp)
>  {
>      Error *err = NULL;
>      SocketAddress *saddr = tcp_build_address(host_port, &err);
> +
>      if (!err) {
> -        socket_start_incoming_migration(saddr, &err);
> +        SocketAddress *address = socket_start_incoming_migration(saddr, &err);
> +
> +        if (address) {
> +            migrate_set_address(address);
> +        }
>      }
>      qapi_free_SocketAddress(saddr);
>      error_propagate(errp, err);
> @@ -195,6 +209,9 @@ void tcp_start_incoming_migration(const char *host_port, Error **errp)
>  void unix_start_incoming_migration(const char *path, Error **errp)
>  {
>      SocketAddress *saddr = unix_build_address(path);
> -    socket_start_incoming_migration(saddr, errp);
> +    SocketAddress *address;
> +
> +    address = socket_start_incoming_migration(saddr, errp);
> +    qapi_free_SocketAddress(address);
>      qapi_free_SocketAddress(saddr);
>  }
> diff --git a/qapi/migration.json b/qapi/migration.json
> index 7f465a1902..a881321de2 100644
> --- a/qapi/migration.json
> +++ b/qapi/migration.json
> @@ -6,6 +6,7 @@
>  ##
>  
>  { 'include': 'common.json' }
> +{ 'include': 'sockets.json' }
>  
>  ##
>  # @MigrationStats:
> @@ -490,6 +491,9 @@
>  #                     and a power of 2
>  #                     (Since 2.11)
>  #
> +# @x-socket-address: Only used for tcp, to know what the real port is
> +#                    (Since 2.12)
> +#
>  # Since: 2.4
>  ##
>  { 'enum': 'MigrationParameter',
> @@ -498,7 +502,7 @@
>             'tls-creds', 'tls-hostname', 'max-bandwidth',
>             'downtime-limit', 'x-checkpoint-delay', 'block-incremental',
>             'x-multifd-channels', 'x-multifd-page-count',
> -           'xbzrle-cache-size' ] }
> +           'xbzrle-cache-size', 'x-socket-address' ] }
>  
>  ##
>  # @MigrateSetParameters:
> @@ -566,6 +570,7 @@
>  #                     needs to be a multiple of the target page size
>  #                     and a power of 2
>  #                     (Since 2.11)
> +#
>  # Since: 2.4
>  ##
>  # TODO either fuse back into MigrationParameters, or make
> @@ -667,6 +672,10 @@
>  #                     needs to be a multiple of the target page size
>  #                     and a power of 2
>  #                     (Since 2.11)
> +#
> +# @x-socket-address: Only used for tcp, to know what the real port is

s/port is/addresses are/

> +#                    (Since 2.12)
> +#
>  # Since: 2.4
>  ##
>  { 'struct': 'MigrationParameters',
> @@ -683,7 +692,8 @@
>              '*block-incremental': 'bool' ,
>              '*x-multifd-channels': 'uint8',
>              '*x-multifd-page-count': 'uint32',
> -            '*xbzrle-cache-size': 'size' } }
> +            '*xbzrle-cache-size': 'size',
> +            '*x-socket-address': 'SocketAddress'} }

This needs to be   ['SocketAddress']  so that it allows an array of
addresses, not just one address, so that it will cope with this
patch to migration code that fixes IPv4/IPv6 dual stack handling :

  https://lists.gnu.org/archive/html/qemu-devel/2018-03/msg03435.html


Regards,
Daniel
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