--- /dev/null
+// SPDX-License-Identifier: GPL-2.0-only
+// Copyright (c) 2020 Facebook Inc.
+
+#include <linux/debugfs.h>
+#include <linux/netdevice.h>
+#include <linux/slab.h>
+#include <net/udp_tunnel.h>
+
+#include "netdevsim.h"
+
+static int
+nsim_udp_tunnel_set_port(struct net_device *dev, unsigned int table,
+                        unsigned int entry, struct udp_tunnel_info *ti)
+{
+       struct netdevsim *ns = netdev_priv(dev);
+       int ret;
+
+       ret = -ns->udp_ports.inject_error;
+       ns->udp_ports.inject_error = 0;
+
+       if (ns->udp_ports.sleep)
+               msleep(ns->udp_ports.sleep);
+
+       if (!ret) {
+               if (ns->udp_ports.ports[table][entry])
+                       ret = -EBUSY;
+               else
+                       ns->udp_ports.ports[table][entry] =
+                               be16_to_cpu(ti->port) << 16 | ti->type;
+       }
+
+       netdev_info(dev, "set [%d, %d] type %d family %d port %d - %d\n",
+                   table, entry, ti->type, ti->sa_family, ntohs(ti->port),
+                   ret);
+       return ret;
+}
+
+static int
+nsim_udp_tunnel_unset_port(struct net_device *dev, unsigned int table,
+                          unsigned int entry, struct udp_tunnel_info *ti)
+{
+       struct netdevsim *ns = netdev_priv(dev);
+       int ret;
+
+       ret = -ns->udp_ports.inject_error;
+       ns->udp_ports.inject_error = 0;
+
+       if (ns->udp_ports.sleep)
+               msleep(ns->udp_ports.sleep);
+       if (!ret) {
+               u32 val = be16_to_cpu(ti->port) << 16 | ti->type;
+
+               if (val == ns->udp_ports.ports[table][entry])
+                       ns->udp_ports.ports[table][entry] = 0;
+               else
+                       ret = -ENOENT;
+       }
+
+       netdev_info(dev, "unset [%d, %d] type %d family %d port %d - %d\n",
+                   table, entry, ti->type, ti->sa_family, ntohs(ti->port),
+                   ret);
+       return ret;
+}
+
+static int
+nsim_udp_tunnel_sync_table(struct net_device *dev, unsigned int table)
+{
+       struct netdevsim *ns = netdev_priv(dev);
+       struct udp_tunnel_info ti;
+       unsigned int i;
+       int ret;
+
+       ret = -ns->udp_ports.inject_error;
+       ns->udp_ports.inject_error = 0;
+
+       for (i = 0; i < NSIM_UDP_TUNNEL_N_PORTS; i++) {
+               udp_tunnel_nic_get_port(dev, table, i, &ti);
+               ns->udp_ports.ports[table][i] =
+                       be16_to_cpu(ti.port) << 16 | ti.type;
+       }
+
+       return ret;
+}
+
+static const struct udp_tunnel_nic_info nsim_udp_tunnel_info = {
+       .set_port       = nsim_udp_tunnel_set_port,
+       .unset_port     = nsim_udp_tunnel_unset_port,
+       .sync_table     = nsim_udp_tunnel_sync_table,
+
+       .tables = {
+               {
+                       .n_entries      = NSIM_UDP_TUNNEL_N_PORTS,
+                       .tunnel_types   = UDP_TUNNEL_TYPE_VXLAN,
+               },
+               {
+                       .n_entries      = NSIM_UDP_TUNNEL_N_PORTS,
+                       .tunnel_types   = UDP_TUNNEL_TYPE_GENEVE |
+                                         UDP_TUNNEL_TYPE_VXLAN_GPE,
+               },
+       },
+};
+
+static ssize_t
+nsim_udp_tunnels_info_reset_write(struct file *file, const char __user *data,
+                                 size_t count, loff_t *ppos)
+{
+       struct net_device *dev = file->private_data;
+       struct netdevsim *ns = netdev_priv(dev);
+
+       memset(&ns->udp_ports.ports, 0, sizeof(ns->udp_ports.ports));
+       rtnl_lock();
+       udp_tunnel_nic_reset_ntf(dev);
+       rtnl_unlock();
+
+       return count;
+}
+
+static const struct file_operations nsim_udp_tunnels_info_reset_fops = {
+       .open = simple_open,
+       .write = nsim_udp_tunnels_info_reset_write,
+       .llseek = generic_file_llseek,
+};
+
+int nsim_udp_tunnels_info_create(struct nsim_dev *nsim_dev,
+                                struct net_device *dev)
+{
+       struct netdevsim *ns = netdev_priv(dev);
+       struct udp_tunnel_nic_info *info;
+
+       debugfs_create_u32("udp_ports_inject_error", 0600,
+                          ns->nsim_dev_port->ddir,
+                          &ns->udp_ports.inject_error);
+
+       ns->udp_ports.dfs_ports[0].array = ns->udp_ports.ports[0];
+       ns->udp_ports.dfs_ports[0].n_elements = NSIM_UDP_TUNNEL_N_PORTS;
+       debugfs_create_u32_array("udp_ports_table0", 0400,
+                                ns->nsim_dev_port->ddir,
+                                &ns->udp_ports.dfs_ports[0]);
+
+       ns->udp_ports.dfs_ports[1].array = ns->udp_ports.ports[1];
+       ns->udp_ports.dfs_ports[1].n_elements = NSIM_UDP_TUNNEL_N_PORTS;
+       debugfs_create_u32_array("udp_ports_table1", 0400,
+                                ns->nsim_dev_port->ddir,
+                                &ns->udp_ports.dfs_ports[1]);
+
+       debugfs_create_file("udp_ports_reset", 0200, ns->nsim_dev_port->ddir,
+                           dev, &nsim_udp_tunnels_info_reset_fops);
+
+       /* Note: it's not normal to allocate the info struct like this!
+        * Drivers are expected to use a static const one, here we're testing.
+        */
+       info = kmemdup(&nsim_udp_tunnel_info, sizeof(nsim_udp_tunnel_info),
+                      GFP_KERNEL);
+       if (!info)
+               return -ENOMEM;
+       ns->udp_ports.sleep = nsim_dev->udp_ports.sleep;
+
+       if (nsim_dev->udp_ports.sync_all) {
+               info->set_port = NULL;
+               info->unset_port = NULL;
+       } else {
+               info->sync_table = NULL;
+       }
+
+       if (ns->udp_ports.sleep)
+               info->flags |= UDP_TUNNEL_NIC_INFO_MAY_SLEEP;
+       if (nsim_dev->udp_ports.open_only)
+               info->flags |= UDP_TUNNEL_NIC_INFO_OPEN_ONLY;
+       if (nsim_dev->udp_ports.ipv4_only)
+               info->flags |= UDP_TUNNEL_NIC_INFO_IPV4_ONLY;
+
+       dev->udp_tunnel_nic_info = info;
+       return 0;
+}
+
+void nsim_udp_tunnels_info_destroy(struct net_device *dev)
+{
+       kfree(dev->udp_tunnel_nic_info);
+       dev->udp_tunnel_nic_info = NULL;
+}
+
+void nsim_udp_tunnels_debugfs_create(struct nsim_dev *nsim_dev)
+{
+       debugfs_create_bool("udp_ports_sync_all", 0600, nsim_dev->ddir,
+                           &nsim_dev->udp_ports.sync_all);
+       debugfs_create_bool("udp_ports_open_only", 0600, nsim_dev->ddir,
+                           &nsim_dev->udp_ports.open_only);
+       debugfs_create_bool("udp_ports_ipv4_only", 0600, nsim_dev->ddir,
+                           &nsim_dev->udp_ports.ipv4_only);
+       debugfs_create_u32("udp_ports_sleep", 0600, nsim_dev->ddir,
+                          &nsim_dev->udp_ports.sleep);
+}