openvswitch: Re-add CONFIG_OPENVSWITCH_VXLAN

This readds the config option CONFIG_OPENVSWITCH_VXLAN to avoid a
hard dependency of OVS on VXLAN. It moves the VXLAN config compat
code to vport-vxlan.c and allows compliation as a module.

Fixes: 614732eaa12d ("openvswitch: Use regular VXLAN net_device device")
Fixes: 2661371ace96 ("openvswitch: fix compilation when vxlan is a module")
Cc: Pravin B Shelar <pshelar@nicira.com>
Cc: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Signed-off-by: Thomas Graf <tgraf@suug.ch>
Acked-by: Pravin B Shelar <pshelar@nicira.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/openvswitch/vport-vxlan.c b/net/openvswitch/vport-vxlan.c
new file mode 100644
index 0000000..5471733
--- /dev/null
+++ b/net/openvswitch/vport-vxlan.c
@@ -0,0 +1,207 @@
+/*
+ * Copyright (c) 2014 Nicira, Inc.
+ * Copyright (c) 2013 Cisco Systems, Inc.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of version 2 of the GNU General Public
+ * License as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+ * 02110-1301, USA
+ */
+
+#include <linux/kernel.h>
+#include <linux/skbuff.h>
+#include <linux/openvswitch.h>
+#include <linux/module.h>
+#include <net/udp.h>
+#include <net/ip_tunnels.h>
+#include <net/rtnetlink.h>
+#include <net/vxlan.h>
+
+#include "datapath.h"
+#include "vport.h"
+#include "vport-netdev.h"
+
+static struct vport_ops ovs_vxlan_netdev_vport_ops;
+
+static int vxlan_get_options(const struct vport *vport, struct sk_buff *skb)
+{
+	struct vxlan_dev *vxlan = netdev_priv(vport->dev);
+	__be16 dst_port = vxlan->cfg.dst_port;
+
+	if (nla_put_u16(skb, OVS_TUNNEL_ATTR_DST_PORT, ntohs(dst_port)))
+		return -EMSGSIZE;
+
+	if (vxlan->flags & VXLAN_F_GBP) {
+		struct nlattr *exts;
+
+		exts = nla_nest_start(skb, OVS_TUNNEL_ATTR_EXTENSION);
+		if (!exts)
+			return -EMSGSIZE;
+
+		if (vxlan->flags & VXLAN_F_GBP &&
+		    nla_put_flag(skb, OVS_VXLAN_EXT_GBP))
+			return -EMSGSIZE;
+
+		nla_nest_end(skb, exts);
+	}
+
+	return 0;
+}
+
+static const struct nla_policy exts_policy[OVS_VXLAN_EXT_MAX + 1] = {
+	[OVS_VXLAN_EXT_GBP]	= { .type = NLA_FLAG, },
+};
+
+static int vxlan_configure_exts(struct vport *vport, struct nlattr *attr,
+				struct vxlan_config *conf)
+{
+	struct nlattr *exts[OVS_VXLAN_EXT_MAX + 1];
+	int err;
+
+	if (nla_len(attr) < sizeof(struct nlattr))
+		return -EINVAL;
+
+	err = nla_parse_nested(exts, OVS_VXLAN_EXT_MAX, attr, exts_policy);
+	if (err < 0)
+		return err;
+
+	if (exts[OVS_VXLAN_EXT_GBP])
+		conf->flags |= VXLAN_F_GBP;
+
+	return 0;
+}
+
+static struct vport *vxlan_tnl_create(const struct vport_parms *parms)
+{
+	struct net *net = ovs_dp_get_net(parms->dp);
+	struct nlattr *options = parms->options;
+	struct net_device *dev;
+	struct vport *vport;
+	struct nlattr *a;
+	int err;
+	struct vxlan_config conf = {
+		.no_share = true,
+		.flags = VXLAN_F_FLOW_BASED | VXLAN_F_COLLECT_METADATA,
+	};
+
+	if (!options) {
+		err = -EINVAL;
+		goto error;
+	}
+
+	a = nla_find_nested(options, OVS_TUNNEL_ATTR_DST_PORT);
+	if (a && nla_len(a) == sizeof(u16)) {
+		conf.dst_port = htons(nla_get_u16(a));
+	} else {
+		/* Require destination port from userspace. */
+		err = -EINVAL;
+		goto error;
+	}
+
+	vport = ovs_vport_alloc(0, &ovs_vxlan_netdev_vport_ops, parms);
+	if (IS_ERR(vport))
+		return vport;
+
+	a = nla_find_nested(options, OVS_TUNNEL_ATTR_EXTENSION);
+	if (a) {
+		err = vxlan_configure_exts(vport, a, &conf);
+		if (err) {
+			ovs_vport_free(vport);
+			goto error;
+		}
+	}
+
+	rtnl_lock();
+	dev = vxlan_dev_create(net, parms->name, NET_NAME_USER, &conf);
+	if (IS_ERR(dev)) {
+		rtnl_unlock();
+		ovs_vport_free(vport);
+		return ERR_CAST(dev);
+	}
+
+	dev_change_flags(dev, dev->flags | IFF_UP);
+	rtnl_unlock();
+	return vport;
+error:
+	return ERR_PTR(err);
+}
+
+static struct vport *vxlan_create(const struct vport_parms *parms)
+{
+	struct vport *vport;
+
+	vport = vxlan_tnl_create(parms);
+	if (IS_ERR(vport))
+		return vport;
+
+	return ovs_netdev_link(vport, parms->name);
+}
+
+static void vxlan_destroy(struct vport *vport)
+{
+	rtnl_lock();
+	if (vport->dev->priv_flags & IFF_OVS_DATAPATH)
+		ovs_netdev_detach_dev(vport);
+
+	/* Early release so we can unregister the device */
+	dev_put(vport->dev);
+	rtnl_delete_link(vport->dev);
+	vport->dev = NULL;
+	rtnl_unlock();
+
+	call_rcu(&vport->rcu, ovs_vport_free_rcu);
+}
+
+static int vxlan_get_egress_tun_info(struct vport *vport, struct sk_buff *skb,
+				     struct ip_tunnel_info *egress_tun_info)
+{
+	struct vxlan_dev *vxlan = netdev_priv(vport->dev);
+	struct net *net = ovs_dp_get_net(vport->dp);
+	__be16 dst_port = vxlan_dev_dst_port(vxlan);
+	__be16 src_port;
+	int port_min;
+	int port_max;
+
+	inet_get_local_port_range(net, &port_min, &port_max);
+	src_port = udp_flow_src_port(net, skb, 0, 0, true);
+
+	return ovs_tunnel_get_egress_info(egress_tun_info, net,
+					  OVS_CB(skb)->egress_tun_info,
+					  IPPROTO_UDP, skb->mark,
+					  src_port, dst_port);
+}
+
+static struct vport_ops ovs_vxlan_netdev_vport_ops = {
+	.type			= OVS_VPORT_TYPE_VXLAN,
+	.create			= vxlan_create,
+	.destroy		= vxlan_destroy,
+	.get_options		= vxlan_get_options,
+	.send			= ovs_netdev_send,
+	.get_egress_tun_info	= vxlan_get_egress_tun_info,
+};
+
+static int __init ovs_vxlan_tnl_init(void)
+{
+	return ovs_vport_ops_register(&ovs_vxlan_netdev_vport_ops);
+}
+
+static void __exit ovs_vxlan_tnl_exit(void)
+{
+	ovs_vport_ops_unregister(&ovs_vxlan_netdev_vport_ops);
+}
+
+module_init(ovs_vxlan_tnl_init);
+module_exit(ovs_vxlan_tnl_exit);
+
+MODULE_DESCRIPTION("OVS: VXLAN switching port");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("vport-type-4");