Re: [Qemu-devel] [PATCH v10 04/24] migration: Set the migration tcp port

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

On Wed, Mar 07, 2018 at 11:59:50AM +0100, Juan Quintela wrote:
> We can set the port parameter as zero.  This patch lets us know what
> port the system was choosen for us.  Now we can migrate to this place.
> 
> Signed-off-by: Juan Quintela <quintela@redhat.com>
> 
> --
> 
> This was migrate_set_uri(), but as we only need the tcp_port, change
> to that one.
> ---
>  migration/migration.c | 10 ++++++++++
>  migration/migration.h |  2 ++
>  migration/socket.c    | 35 ++++++++++++++++++++++++++++++-----
>  3 files changed, 42 insertions(+), 5 deletions(-)
> 
> diff --git a/migration/migration.c b/migration/migration.c
> index 31b16a335b..c398665de7 100644
> --- a/migration/migration.c
> +++ b/migration/migration.c
> @@ -268,6 +268,16 @@ int migrate_send_rp_req_pages(MigrationIncomingState *mis, const char *rbname,
>      return migrate_send_rp_message(mis, msg_type, msglen, bufc);
>  }
>  
> +void migrate_set_port(const uint16_t port, Error **errp)
> +{
> +    MigrateSetParameters p = {
> +        .has_x_tcp_port = true,
> +        .x_tcp_port = port,
> +    };
> +
> +    qmp_migrate_set_parameters(&p, errp);
> +}

This is really not nice - it is requiring the QMP  'migrate-set-parameters'
command to accept an extra field that is never something we want the end
user to be allowed to set. We should not use the public QMP schema for
data items we are just passing between 2 internal pieces of code.

>  void qemu_start_incoming_migration(const char *uri, Error **errp)
>  {
>      const char *p;
> diff --git a/migration/migration.h b/migration/migration.h
> index 08c5d2ded1..f40014cf94 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_port(const uint16_t port, Error **errp);
> +
>  #endif
> diff --git a/migration/socket.c b/migration/socket.c
> index e090097077..08606c665d 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"
> @@ -160,17 +161,24 @@ 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),
> @@ -178,14 +186,28 @@ 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) {
> +            unsigned long long port;
> +
> +            if (parse_uint_full(address->u.inet.port, &port, 10) < 0) {
> +                error_setg(errp, "error parsing port in '%s'",
> +                           address->u.inet.port);
> +            } else {
> +                migrate_set_port(port, errp);
> +            }
> +            qapi_free_SocketAddress(address);
> +        }
>      }
>      qapi_free_SocketAddress(saddr);
>      error_propagate(errp, err);
> @@ -194,6 +216,9 @@ 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);
>  }
> -- 
> 2.14.3
> 
> 

Regards,
Daniel
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