src/vnet/devices/tap/tap.c - fdio/vpp - Gitiles

 /*
  *------------------------------------------------------------------
  * Copyright (c) 2017 Cisco and/or its affiliates.
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
  * You may obtain a copy of the License at:
  *
  *     http://www.apache.org/licenses/LICENSE-2.0
  *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  * See the License for the specific language governing permissions and
  * limitations under the License.
  *------------------------------------------------------------------
  */

 #include <sys/types.h>
 #include <sys/stat.h>
 #include <fcntl.h>
 #include <net/if.h>
 #include <linux/if_tun.h>
 #include <sys/ioctl.h>
 #include <linux/virtio_net.h>
 #include <linux/vhost.h>
 #include <sys/eventfd.h>

 #include <linux/netlink.h>
 #include <linux/rtnetlink.h>

 #include <vlib/vlib.h>
 #include <vlib/unix/unix.h>
 #include <vnet/ethernet/ethernet.h>
 #include <vnet/ip/ip4_packet.h>
 #include <vnet/ip/ip6_packet.h>
 #include <vnet/devices/netlink.h>
 #include <vnet/devices/virtio/virtio.h>
 #include <vnet/devices/tap/tap.h>

 #define _IOCTL(fd,a,...) \
   if (ioctl (fd, a, __VA_ARGS__) < 0) \
     { \
       err = clib_error_return_unix (0, "ioctl(" #a ")"); \
       goto error; \
     }

 static u32
 virtio_eth_flag_change (vnet_main_t * vnm, vnet_hw_interface_t * hi,
 			u32 flags)
 {
   /* nothing for now */
   //TODO On MTU change call vnet_netlink_set_if_mtu
   return 0;
 }

 void
 tap_create_if (vlib_main_t * vm, tap_create_if_args_t * args)
 {
   vnet_main_t *vnm = vnet_get_main ();
   virtio_main_t *vim = &virtio_main;
   vnet_sw_interface_t *sw;
   vnet_hw_interface_t *hw;
   int i, fd = -1;
   struct ifreq ifr;
   size_t hdrsz;
   struct vhost_memory *vhost_mem = 0;
   virtio_if_t *vif = 0;
   clib_error_t *err = 0;

   memset (&ifr, 0, sizeof (ifr));
   pool_get (vim->interfaces, vif);
   vif->dev_instance = vif - vim->interfaces;
   vif->tap_fd = -1;

   if ((vif->fd = open ("/dev/vhost-net", O_RDWR | O_NONBLOCK)) < 0)
     {
       args->rv = VNET_API_ERROR_SYSCALL_ERROR_1;
       args->error = clib_error_return_unix (0, "open '/dev/vhost-net'");
       goto error;
     }

   _IOCTL (vif->fd, VHOST_GET_FEATURES, &vif->remote_features);

   if ((vif->remote_features & (1ULL << VIRTIO_NET_F_MRG_RXBUF)) == 0)
     {
       args->rv = VNET_API_ERROR_UNSUPPORTED;
       args->error = clib_error_return (0, "vhost-net backend doesn't support "
 				       "VIRTIO_NET_F_MRG_RXBUF feature");
       goto error;
     }

   if ((vif->remote_features & (1ULL << VIRTIO_RING_F_INDIRECT_DESC)) == 0)
     {
       args->rv = VNET_API_ERROR_UNSUPPORTED;
       args->error = clib_error_return (0, "vhost-net backend doesn't support "
 				       "VIRTIO_RING_F_INDIRECT_DESC feature");
       goto error;
     }

   if ((vif->remote_features & (1ULL << VIRTIO_F_VERSION_1)) == 0)
     {
       args->rv = VNET_API_ERROR_UNSUPPORTED;
       args->error = clib_error_return (0, "vhost-net backend doesn't support "
 				       "VIRTIO_F_VERSION_1 features");
       goto error;
     }

   vif->features |= 1ULL << VIRTIO_NET_F_MRG_RXBUF;
   vif->features |= 1ULL << VIRTIO_F_VERSION_1;
   vif->features |= 1ULL << VIRTIO_RING_F_INDIRECT_DESC;

   _IOCTL (vif->fd, VHOST_SET_FEATURES, &vif->features);

   if ((vif->tap_fd = open ("/dev/net/tun", O_RDWR | O_NONBLOCK)) < 0)
     {
       args->rv = VNET_API_ERROR_SYSCALL_ERROR_2;
       args->error = clib_error_return_unix (0, "open '/dev/net/tun'");
       goto error;
     }

   ifr.ifr_flags = IFF_TAP | IFF_NO_PI | IFF_ONE_QUEUE | IFF_VNET_HDR;
   strncpy (ifr.ifr_ifrn.ifrn_name, (char *) args->name, IF_NAMESIZE - 1);
   _IOCTL (vif->tap_fd, TUNSETIFF, (void *) &ifr);

   vif->ifindex = if_nametoindex ((char *) args->name);

   unsigned int offload = 0;
   hdrsz = sizeof (struct virtio_net_hdr_v1);
   _IOCTL (vif->tap_fd, TUNSETOFFLOAD, offload);
   _IOCTL (vif->tap_fd, TUNSETVNETHDRSZ, &hdrsz);
   _IOCTL (vif->fd, VHOST_SET_OWNER, 0);

   if (args->host_bridge)
     {
       int master_ifindex = if_nametoindex ((char *) args->host_bridge);
       args->error = vnet_netlink_set_if_master (vif->ifindex, master_ifindex);
       if (args->error)
 	{
 	  args->rv = VNET_API_ERROR_NETLINK_ERROR;
 	  goto error;
 	}
     }

   if (args->host_namespace)
     {
       args->error = vnet_netlink_set_if_namespace (vif->ifindex,
 						   (char *)
 						   args->host_namespace);
       if (args->error)
 	{
 	  args->rv = VNET_API_ERROR_NETLINK_ERROR;
 	  goto error;
 	}
     }

   if (args->host_ip4_prefix_len)
     {
       args->error = vnet_netlink_add_ip4_addr (vif->ifindex,
 					       &args->host_ip4_addr,
 					       args->host_ip4_prefix_len);
       if (args->error)
 	{
 	  args->rv = VNET_API_ERROR_NETLINK_ERROR;
 	  goto error;
 	}
     }

   if (args->host_ip6_prefix_len)
     {
       args->error = vnet_netlink_add_ip6_addr (vif->ifindex,
 					       &args->host_ip6_addr,
 					       args->host_ip6_prefix_len);
       if (args->error)
 	{
 	  args->rv = VNET_API_ERROR_NETLINK_ERROR;
 	  goto error;
 	}
     }

   /* Set vhost memory table */
   i = sizeof (struct vhost_memory) + sizeof (struct vhost_memory_region);
   vhost_mem = clib_mem_alloc (i);
   memset (vhost_mem, 0, i);
   vhost_mem->nregions = 1;
   vhost_mem->regions[0].memory_size = (1ULL << 47) - 4096;
   _IOCTL (vif->fd, VHOST_SET_MEM_TABLE, vhost_mem);

   if ((args->error = virtio_vring_init (vm, vif, 0, args->rx_ring_sz)))
     {
       args->rv = VNET_API_ERROR_INIT_FAILED;
       goto error;
     }

   if ((args->error = virtio_vring_init (vm, vif, 1, args->tx_ring_sz)))
     {
       args->rv = VNET_API_ERROR_INIT_FAILED;
       goto error;
     }

   /* set host side up */
   if ((fd = socket (AF_INET, SOCK_STREAM, 0)) > 0)
     {
       memset (&ifr, 0, sizeof (struct ifreq));
       strncpy (ifr.ifr_name, (char *) args->name, sizeof (ifr.ifr_name) - 1);
       _IOCTL (fd, SIOCGIFFLAGS, (void *) &ifr);
       ifr.ifr_flags |= IFF_UP | IFF_RUNNING;
       _IOCTL (fd, SIOCSIFFLAGS, (void *) &ifr);
     }

   if (!args->hw_addr_set)
     {
       f64 now = vlib_time_now (vm);
       u32 rnd;
       rnd = (u32) (now * 1e6);
       rnd = random_u32 (&rnd);

       memcpy (args->hw_addr + 2, &rnd, sizeof (rnd));
       args->hw_addr[0] = 2;
       args->hw_addr[1] = 0xfe;
     }
   vif->name = args->name;
   args->name = 0;
   vif->net_ns = args->host_namespace;
   args->host_namespace = 0;
   args->error = ethernet_register_interface (vnm, virtio_device_class.index,
 					     vif->dev_instance, args->hw_addr,
 					     &vif->hw_if_index,
 					     virtio_eth_flag_change);
   if (args->error)
     {
       args->rv = VNET_API_ERROR_INVALID_REGISTRATION;
       goto error;
     }

   sw = vnet_get_hw_sw_interface (vnm, vif->hw_if_index);
   vif->sw_if_index = sw->sw_if_index;
   args->sw_if_index = vif->sw_if_index;
   hw = vnet_get_hw_interface (vnm, vif->hw_if_index);
   hw->flags |= VNET_HW_INTERFACE_FLAG_SUPPORTS_INT_MODE;
   vnet_hw_interface_set_input_node (vnm, vif->hw_if_index,
 				    virtio_input_node.index);
   vnet_hw_interface_assign_rx_thread (vnm, vif->hw_if_index, 0, ~0);
   vnet_hw_interface_set_rx_mode (vnm, vif->hw_if_index, 0,
 				 VNET_HW_INTERFACE_RX_MODE_DEFAULT);
   vif->per_interface_next_index = ~0;
   vif->type = VIRTIO_IF_TYPE_TAP;
   vif->flags |= VIRTIO_IF_FLAG_ADMIN_UP;
   vnet_hw_interface_set_flags (vnm, vif->hw_if_index,
 			       VNET_HW_INTERFACE_FLAG_LINK_UP);
   goto done;

 error:
   if (err)
     {
       ASSERT (args->error == 0);
       args->error = err;
       args->rv = VNET_API_ERROR_SYSCALL_ERROR_3;
     }
   if (vif->tap_fd != -1)
     close (vif->tap_fd);
   if (vif->fd != -1)
     close (vif->fd);
   vec_foreach_index (i, vif->vrings) virtio_vring_free (vif, i);
   memset (vif, 0, sizeof (virtio_if_t));
   pool_put (vim->interfaces, vif);

 done:
   if (vhost_mem)
     clib_mem_free (vhost_mem);
   if (fd != -1)
     close (fd);
 }

 int
 tap_delete_if (vlib_main_t * vm, u32 sw_if_index)
 {
   vnet_main_t *vnm = vnet_get_main ();
   virtio_main_t *mm = &virtio_main;
   int i;
   virtio_if_t *vif;
   vnet_hw_interface_t *hw;

   hw = vnet_get_sup_hw_interface (vnm, sw_if_index);
   if (hw == NULL || virtio_device_class.index != hw->dev_class_index)
     return VNET_API_ERROR_INVALID_SW_IF_INDEX;

   vif = pool_elt_at_index (mm->interfaces, hw->dev_instance);

   /* bring down the interface */
   vnet_hw_interface_set_flags (vnm, vif->hw_if_index, 0);
   vnet_sw_interface_set_flags (vnm, vif->sw_if_index, 0);

   ethernet_delete_interface (vnm, vif->hw_if_index);
   vif->hw_if_index = ~0;

   if (vif->tap_fd != -1)
     close (vif->tap_fd);
   if (vif->fd != -1)
     close (vif->fd);

   vec_foreach_index (i, vif->vrings) virtio_vring_free (vif, i);
   vec_free (vif->vrings);

   memset (vif, 0, sizeof (*vif));
   pool_put (mm->interfaces, vif);

   return 0;
 }

 int
 tap_dump_ifs (tap_interface_details_t ** out_tapids)
 {
   vnet_main_t *vnm = vnet_get_main ();
   virtio_main_t *mm = &virtio_main;
   virtio_if_t *vif;
   vnet_hw_interface_t *hi;
   tap_interface_details_t *r_tapids = NULL;
   tap_interface_details_t *tapid = NULL;

   /* *INDENT-OFF* */
   pool_foreach (vif, mm->interfaces,
     vec_add2(r_tapids, tapid, 1);
     memset (tapid, 0, sizeof (*tapid));
     tapid->sw_if_index = vif->sw_if_index;
     hi = vnet_get_hw_interface (vnm, vif->hw_if_index);
     clib_memcpy(tapid->dev_name, hi->name,
 		MIN (ARRAY_LEN (tapid->dev_name) - 1,
 		     strlen ((const char *) hi->name)));
   );
   /* *INDENT-ON* */

   *out_tapids = r_tapids;

   return 0;
 }

 static clib_error_t *
 tap_init (vlib_main_t * vm)
 {

   return 0;
 }

 VLIB_INIT_FUNCTION (tap_init);

 /*
  * fd.io coding-style-patch-verification: ON
  *
  * Local Variables:
  * eval: (c-set-style "gnu")
  * End:
  */
	/*
	*------------------------------------------------------------------
	* Copyright (c) 2017 Cisco and/or its affiliates.
	* Licensed under the Apache License, Version 2.0 (the "License");
	* you may not use this file except in compliance with the License.
	* You may obtain a copy of the License at:
	*
	* http://www.apache.org/licenses/LICENSE-2.0
	*
	* Unless required by applicable law or agreed to in writing, software
	* distributed under the License is distributed on an "AS IS" BASIS,
	* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
	* See the License for the specific language governing permissions and
	* limitations under the License.
	*------------------------------------------------------------------
	*/

	#include <sys/types.h>
	#include <sys/stat.h>
	#include <fcntl.h>
	#include <net/if.h>
	#include <linux/if_tun.h>
	#include <sys/ioctl.h>
	#include <linux/virtio_net.h>
	#include <linux/vhost.h>
	#include <sys/eventfd.h>

	#include <linux/netlink.h>
	#include <linux/rtnetlink.h>

	#include <vlib/vlib.h>
	#include <vlib/unix/unix.h>
	#include <vnet/ethernet/ethernet.h>
	#include <vnet/ip/ip4_packet.h>
	#include <vnet/ip/ip6_packet.h>
	#include <vnet/devices/netlink.h>
	#include <vnet/devices/virtio/virtio.h>
	#include <vnet/devices/tap/tap.h>

	#define _IOCTL(fd,a,...) \
	if (ioctl (fd, a, __VA_ARGS__) < 0) \
	{ \
	err = clib_error_return_unix (0, "ioctl(" #a ")"); \
	goto error; \
	}

	static u32
	virtio_eth_flag_change (vnet_main_t * vnm, vnet_hw_interface_t * hi,
	u32 flags)
	{
	/* nothing for now */
	//TODO On MTU change call vnet_netlink_set_if_mtu
	return 0;
	}

	void
	tap_create_if (vlib_main_t * vm, tap_create_if_args_t * args)
	{
	vnet_main_t *vnm = vnet_get_main ();
	virtio_main_t *vim = &virtio_main;
	vnet_sw_interface_t *sw;
	vnet_hw_interface_t *hw;
	int i, fd = -1;
	struct ifreq ifr;
	size_t hdrsz;
	struct vhost_memory *vhost_mem = 0;
	virtio_if_t *vif = 0;
	clib_error_t *err = 0;

	memset (&ifr, 0, sizeof (ifr));
	pool_get (vim->interfaces, vif);
	vif->dev_instance = vif - vim->interfaces;
	vif->tap_fd = -1;

	if ((vif->fd = open ("/dev/vhost-net", O_RDWR \| O_NONBLOCK)) < 0)
	{
	args->rv = VNET_API_ERROR_SYSCALL_ERROR_1;
	args->error = clib_error_return_unix (0, "open '/dev/vhost-net'");
	goto error;
	}

	_IOCTL (vif->fd, VHOST_GET_FEATURES, &vif->remote_features);

	if ((vif->remote_features & (1ULL << VIRTIO_NET_F_MRG_RXBUF)) == 0)
	{
	args->rv = VNET_API_ERROR_UNSUPPORTED;
	args->error = clib_error_return (0, "vhost-net backend doesn't support "
	"VIRTIO_NET_F_MRG_RXBUF feature");
	goto error;
	}

	if ((vif->remote_features & (1ULL << VIRTIO_RING_F_INDIRECT_DESC)) == 0)
	{
	args->rv = VNET_API_ERROR_UNSUPPORTED;
	args->error = clib_error_return (0, "vhost-net backend doesn't support "
	"VIRTIO_RING_F_INDIRECT_DESC feature");
	goto error;
	}

	if ((vif->remote_features & (1ULL << VIRTIO_F_VERSION_1)) == 0)
	{
	args->rv = VNET_API_ERROR_UNSUPPORTED;
	args->error = clib_error_return (0, "vhost-net backend doesn't support "
	"VIRTIO_F_VERSION_1 features");
	goto error;
	}

	vif->features \|= 1ULL << VIRTIO_NET_F_MRG_RXBUF;
	vif->features \|= 1ULL << VIRTIO_F_VERSION_1;
	vif->features \|= 1ULL << VIRTIO_RING_F_INDIRECT_DESC;

	_IOCTL (vif->fd, VHOST_SET_FEATURES, &vif->features);

	if ((vif->tap_fd = open ("/dev/net/tun", O_RDWR \| O_NONBLOCK)) < 0)
	{
	args->rv = VNET_API_ERROR_SYSCALL_ERROR_2;
	args->error = clib_error_return_unix (0, "open '/dev/net/tun'");
	goto error;
	}

	ifr.ifr_flags = IFF_TAP \| IFF_NO_PI \| IFF_ONE_QUEUE \| IFF_VNET_HDR;
	strncpy (ifr.ifr_ifrn.ifrn_name, (char *) args->name, IF_NAMESIZE - 1);
	_IOCTL (vif->tap_fd, TUNSETIFF, (void *) &ifr);

	vif->ifindex = if_nametoindex ((char *) args->name);

	unsigned int offload = 0;
	hdrsz = sizeof (struct virtio_net_hdr_v1);
	_IOCTL (vif->tap_fd, TUNSETOFFLOAD, offload);
	_IOCTL (vif->tap_fd, TUNSETVNETHDRSZ, &hdrsz);
	_IOCTL (vif->fd, VHOST_SET_OWNER, 0);

	if (args->host_bridge)
	{
	int master_ifindex = if_nametoindex ((char *) args->host_bridge);
	args->error = vnet_netlink_set_if_master (vif->ifindex, master_ifindex);
	if (args->error)
	{
	args->rv = VNET_API_ERROR_NETLINK_ERROR;
	goto error;
	}
	}

	if (args->host_namespace)
	{
	args->error = vnet_netlink_set_if_namespace (vif->ifindex,
	(char *)
	args->host_namespace);
	if (args->error)
	{
	args->rv = VNET_API_ERROR_NETLINK_ERROR;
	goto error;
	}
	}

	if (args->host_ip4_prefix_len)
	{
	args->error = vnet_netlink_add_ip4_addr (vif->ifindex,
	&args->host_ip4_addr,
	args->host_ip4_prefix_len);
	if (args->error)
	{
	args->rv = VNET_API_ERROR_NETLINK_ERROR;
	goto error;
	}
	}

	if (args->host_ip6_prefix_len)
	{
	args->error = vnet_netlink_add_ip6_addr (vif->ifindex,
	&args->host_ip6_addr,
	args->host_ip6_prefix_len);
	if (args->error)
	{
	args->rv = VNET_API_ERROR_NETLINK_ERROR;
	goto error;
	}
	}

	/* Set vhost memory table */
	i = sizeof (struct vhost_memory) + sizeof (struct vhost_memory_region);
	vhost_mem = clib_mem_alloc (i);
	memset (vhost_mem, 0, i);
	vhost_mem->nregions = 1;
	vhost_mem->regions[0].memory_size = (1ULL << 47) - 4096;
	_IOCTL (vif->fd, VHOST_SET_MEM_TABLE, vhost_mem);

	if ((args->error = virtio_vring_init (vm, vif, 0, args->rx_ring_sz)))
	{
	args->rv = VNET_API_ERROR_INIT_FAILED;
	goto error;
	}

	if ((args->error = virtio_vring_init (vm, vif, 1, args->tx_ring_sz)))
	{
	args->rv = VNET_API_ERROR_INIT_FAILED;
	goto error;
	}

	/* set host side up */
	if ((fd = socket (AF_INET, SOCK_STREAM, 0)) > 0)
	{
	memset (&ifr, 0, sizeof (struct ifreq));
	strncpy (ifr.ifr_name, (char *) args->name, sizeof (ifr.ifr_name) - 1);
	_IOCTL (fd, SIOCGIFFLAGS, (void *) &ifr);
	ifr.ifr_flags \|= IFF_UP \| IFF_RUNNING;
	_IOCTL (fd, SIOCSIFFLAGS, (void *) &ifr);
	}

	if (!args->hw_addr_set)
	{
	f64 now = vlib_time_now (vm);
	u32 rnd;
	rnd = (u32) (now * 1e6);
	rnd = random_u32 (&rnd);

	memcpy (args->hw_addr + 2, &rnd, sizeof (rnd));
	args->hw_addr[0] = 2;
	args->hw_addr[1] = 0xfe;
	}
	vif->name = args->name;
	args->name = 0;
	vif->net_ns = args->host_namespace;
	args->host_namespace = 0;
	args->error = ethernet_register_interface (vnm, virtio_device_class.index,
	vif->dev_instance, args->hw_addr,
	&vif->hw_if_index,
	virtio_eth_flag_change);
	if (args->error)
	{
	args->rv = VNET_API_ERROR_INVALID_REGISTRATION;
	goto error;
	}

	sw = vnet_get_hw_sw_interface (vnm, vif->hw_if_index);
	vif->sw_if_index = sw->sw_if_index;
	args->sw_if_index = vif->sw_if_index;
	hw = vnet_get_hw_interface (vnm, vif->hw_if_index);
	hw->flags \|= VNET_HW_INTERFACE_FLAG_SUPPORTS_INT_MODE;
	vnet_hw_interface_set_input_node (vnm, vif->hw_if_index,
	virtio_input_node.index);
	vnet_hw_interface_assign_rx_thread (vnm, vif->hw_if_index, 0, ~0);
	vnet_hw_interface_set_rx_mode (vnm, vif->hw_if_index, 0,
	VNET_HW_INTERFACE_RX_MODE_DEFAULT);
	vif->per_interface_next_index = ~0;
	vif->type = VIRTIO_IF_TYPE_TAP;
	vif->flags \|= VIRTIO_IF_FLAG_ADMIN_UP;
	vnet_hw_interface_set_flags (vnm, vif->hw_if_index,
	VNET_HW_INTERFACE_FLAG_LINK_UP);
	goto done;

	error:
	if (err)
	{
	ASSERT (args->error == 0);
	args->error = err;
	args->rv = VNET_API_ERROR_SYSCALL_ERROR_3;
	}
	if (vif->tap_fd != -1)
	close (vif->tap_fd);
	if (vif->fd != -1)
	close (vif->fd);
	vec_foreach_index (i, vif->vrings) virtio_vring_free (vif, i);
	memset (vif, 0, sizeof (virtio_if_t));
	pool_put (vim->interfaces, vif);

	done:
	if (vhost_mem)
	clib_mem_free (vhost_mem);
	if (fd != -1)
	close (fd);
	}

	int
	tap_delete_if (vlib_main_t * vm, u32 sw_if_index)
	{
	vnet_main_t *vnm = vnet_get_main ();
	virtio_main_t *mm = &virtio_main;
	int i;
	virtio_if_t *vif;
	vnet_hw_interface_t *hw;

	hw = vnet_get_sup_hw_interface (vnm, sw_if_index);
	if (hw == NULL \|\| virtio_device_class.index != hw->dev_class_index)
	return VNET_API_ERROR_INVALID_SW_IF_INDEX;

	vif = pool_elt_at_index (mm->interfaces, hw->dev_instance);

	/* bring down the interface */
	vnet_hw_interface_set_flags (vnm, vif->hw_if_index, 0);
	vnet_sw_interface_set_flags (vnm, vif->sw_if_index, 0);

	ethernet_delete_interface (vnm, vif->hw_if_index);
	vif->hw_if_index = ~0;

	if (vif->tap_fd != -1)
	close (vif->tap_fd);
	if (vif->fd != -1)
	close (vif->fd);

	vec_foreach_index (i, vif->vrings) virtio_vring_free (vif, i);
	vec_free (vif->vrings);

	memset (vif, 0, sizeof (*vif));
	pool_put (mm->interfaces, vif);

	return 0;
	}

	int
	tap_dump_ifs (tap_interface_details_t ** out_tapids)
	{
	vnet_main_t *vnm = vnet_get_main ();
	virtio_main_t *mm = &virtio_main;
	virtio_if_t *vif;
	vnet_hw_interface_t *hi;
	tap_interface_details_t *r_tapids = NULL;
	tap_interface_details_t *tapid = NULL;

	/* INDENT-OFF */
	pool_foreach (vif, mm->interfaces,
	vec_add2(r_tapids, tapid, 1);
	memset (tapid, 0, sizeof (*tapid));
	tapid->sw_if_index = vif->sw_if_index;
	hi = vnet_get_hw_interface (vnm, vif->hw_if_index);
	clib_memcpy(tapid->dev_name, hi->name,
	MIN (ARRAY_LEN (tapid->dev_name) - 1,
	strlen ((const char *) hi->name)));
	);
	/* INDENT-ON */

	*out_tapids = r_tapids;

	return 0;
	}

	static clib_error_t *
	tap_init (vlib_main_t * vm)
	{

	return 0;
	}

	VLIB_INIT_FUNCTION (tap_init);

	/*
	* fd.io coding-style-patch-verification: ON
	*
	* Local Variables:
	* eval: (c-set-style "gnu")
	* End:
	*/