text: /*
   * Copyright (c) 2015 Nicira, Inc.
   *
   * This program is free software; you can redistribute it and/or
   * modify it under the terms of the GNU General Public License
   * as published by the Free Software Foundation; either version
   * 2 of the License, or (at your option) any later version.
   */
  
  #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  
  #include <linux/in.h>
  #include <linux/ip.h>
  #include <linux/net.h>
  #include <linux/rculist.h>
  #include <linux/udp.h>
  #include <linux/if_vlan.h>
  #include <linux/module.h>
  
  #include <net/stt.h>
  #include <net/icmp.h>
  #include <net/ip.h>
  #include <net/route.h>
  #include <net/udp.h>
  #include <net/xfrm.h>
  #include <net/stt.h>
  
  #include "datapath.h"
  #include "vport.h"
  #include "vport-netdev.h"
  
  #ifdef OVS_STT
  static struct vport_ops ovs_stt_vport_ops;
  /**
   * struct stt_port - Keeps track of open UDP ports
   * @dst_port: destination port.
   */
  struct stt_port {
  	u16 port_no;
  };
  
  static inline struct stt_port *stt_vport(const struct vport *vport)
  {
  	return vport_priv(vport);
  }
  
  static int stt_get_options(const struct vport *vport,
  			      struct sk_buff *skb)
  {
  	struct stt_port *stt_port = stt_vport(vport);
  
  	if (nla_put_u16(skb, OVS_TUNNEL_ATTR_DST_PORT, stt_port->port_no))
  		return -EMSGSIZE;
  	return 0;
  }
  
  static struct vport *stt_tnl_create(const struct vport_parms *parms)
  {
  	struct net *net = ovs_dp_get_net(parms->dp);
  	struct nlattr *options = parms->options;
  	struct stt_port *stt_port;
  	struct net_device *dev;
  	struct vport *vport;
  	struct nlattr *a;
  	u16 dst_port;
  	int err;
  
  	if (!options) {
  		err = -EINVAL;
  		goto error;
  	}
  
  	a = nla_find_nested(options, OVS_TUNNEL_ATTR_DST_PORT);
  	if (a && nla_len(a) == sizeof(u16)) {
  		dst_port = nla_get_u16(a);
  	} else {
  		/* Require destination port from userspace. */
  		err = -EINVAL;
  		goto error;
  	}
  
  	vport = ovs_vport_alloc(sizeof(struct stt_port),
  				&ovs_stt_vport_ops, parms);
  	if (IS_ERR(vport))
  		return vport;
  
  	stt_port = stt_vport(vport);
  	stt_port->port_no = dst_port;
  
  	rtnl_lock();
  	dev = stt_dev_create_fb(net, parms->name, NET_NAME_USER, dst_port);
  	if (IS_ERR(dev)) {
  		rtnl_unlock();
  		ovs_vport_free(vport);
  		return ERR_CAST(dev);
  	}
  
  	err = dev_change_flags(dev, dev->flags | IFF_UP, NULL);
  	if (err < 0) {
  		rtnl_delete_link(dev);
  		rtnl_unlock();
  		ovs_vport_free(vport);
  		goto error;
  	}
  
  	rtnl_unlock();
  	return vport;
  error:
  	return ERR_PTR(err);
  }
  
  static struct vport *stt_create(const struct vport_parms *parms)
  {
  	struct vport *vport;
  
  	vport = stt_tnl_create(parms);
  	if (IS_ERR(vport))
  		return vport;
  
  	return ovs_netdev_link(vport, parms->name);
  }
  
  static struct vport_ops ovs_stt_vport_ops = {
  	.type		= OVS_VPORT_TYPE_STT,
  	.create		= stt_create,
  	.destroy	= ovs_netdev_tunnel_destroy,
  	.get_options	= stt_get_options,
  #ifndef USE_UPSTREAM_TUNNEL
  	.fill_metadata_dst = stt_fill_metadata_dst,
  #endif
  	.send		= ovs_stt_xmit,
  };
  
  static int __init ovs_stt_tnl_init(void)
  {
  	return ovs_vport_ops_register(&ovs_stt_vport_ops);
  }
  
  static void __exit ovs_stt_tnl_exit(void)
  {
  	ovs_vport_ops_unregister(&ovs_stt_vport_ops);
  }
  
  module_init(ovs_stt_tnl_init);
  module_exit(ovs_stt_tnl_exit);
  
  MODULE_DESCRIPTION("OVS: STT switching port");
  MODULE_LICENSE("GPL");
  MODULE_ALIAS("vport-type-106");
  #endif
  