text: /*
   * Copyright (C) 2011-2014 Matteo Landi, Luigi Rizzo. All rights reserved.
   *
   * Redistribution and use in source and binary forms, with or without
   * modification, are permitted provided that the following conditions
   * are met:
   *
   *   1. Redistributions of source code must retain the above copyright
   *      notice, this list of conditions and the following disclaimer.
   *   2. Redistributions in binary form must reproduce the above copyright
   *      notice, this list of conditions and the following disclaimer in the
   *      documentation and/or other materials provided with the distribution.
   *
   * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``S IS''AND
   * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
   * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   * SUCH DAMAGE.
   */
  
  /*
   * $FreeBSD: head/sys/net/netmap.h 251139 2013-05-30 14:07:14Z luigi $
   *
   * Definitions of constants and the structures used by the netmap
   * framework, for the part visible to both kernel and userspace.
   * Detailed info on netmap is available with "man netmap" or at
   *
   *	http://info.iet.unipi.it/~luigi/netmap/
   *
   * This API is also used to communicate with the VALE software switch
   */
  
  #ifndef _NET_NETMAP_H_
  #define _NET_NETMAP_H_
  
  #define	NETMAP_API	11		/* current API version */
  
  #define	NETMAP_MIN_API	11		/* min and max versions accepted */
  #define	NETMAP_MAX_API	15
  /*
   * Some fields should be cache-aligned to reduce contention.
   * The alignment is architecture and OS dependent, but rather than
   * digging into OS headers to find the exact value we use an estimate
   * that should cover most architectures.
   */
  #define NM_CACHE_ALIGN	128
  
  /*
   * --- Netmap data structures ---
   *
   * The userspace data structures used by netmap are shown below.
   * They are allocated by the kernel and mmap()ed by userspace threads.
   * Pointers are implemented as memory offsets or indexes,
   * so that they can be easily dereferenced in kernel and userspace.
  
     KERNEL (opaque, obviously)
  
    ====================================================================
                                           |
     USERSPACE                             |      struct netmap_ring
                                           +---->+---------------+
                                               / | head,cur,tail |
     struct netmap_if (nifp, 1 per fd)        /  | buf_ofs       |
      +---------------+                      /   | other fields  |
      | ni_tx_rings   |                     /    +===============+
      | ni_rx_rings   |                    /     | buf_idx, len  | slot[0]
      |               |                   /      | flags, ptr    |
      |               |                  /       +---------------+
      +===============+                 /        | buf_idx, len  | slot[1]
      | txring_ofs[0] | (rel.to nifp)--'         | flags, ptr    |
      | txring_ofs[1] |                          +---------------+
       (tx+1 entries)                           (num_slots entries)
      | txring_ofs[t] |                          | buf_idx, len  | slot[n-1]
      +---------------+                          | flags, ptr    |
      | rxring_ofs[0] |                          +---------------+
      | rxring_ofs[1] |
       (rx+1 entries)
      | rxring_ofs[r] |
      +---------------+
  
   * For each "interface" (NIC, host stack, PIPE, VALE switch port) bound to
   * a file descriptor, the mmap()ed region contains a (logically readonly)
   * struct netmap_if pointing to struct netmap_ring's.
   *
   * There is one netmap_ring per physical NIC ring, plus one tx/rx ring
   * pair attached to the host stack (this pair is unused for non-NIC ports).
   *
   * All physical/host stack ports share the same memory region,
   * so that zero-copy can be implemented between them.
   * VALE switch ports instead have separate memory regions.
   *
   * The netmap_ring is the userspace-visible replica of the NIC ring.
   * Each slot has the index of a buffer (MTU-sized and residing in the
   * mmapped region), its length and some flags. An extra 64-bit pointer
   * is provided for user-supplied buffers in the tx path.
   *
   * In user space, the buffer address is computed as
   *	(char *)ring + buf_ofs + index * NETMAP_BUF_SIZE
   *
   * Added in NETMAP_API 11:
   *
   * + NIOCREGIF can request the allocation of extra spare buffers from
   *   the same memory pool. The desired number of buffers must be in
   *   nr_arg3. The ioctl may return fewer buffers, depending on memory
   *   availability. nr_arg3 will return the actual value, and, once
   *   mapped, nifp->ni_bufs_head will be the index of the first buffer.
   *
   *   The buffers are linked to each other using the first uint32_t
   *   as the index. On close, ni_bufs_head must point to the list of
   *   buffers to be released.
   *
   * + NIOCREGIF can request space for extra rings (and buffers)
   *   allocated in the same memory space. The number of extra rings
   *   is in nr_arg1, and is advisory. This is a no-op on NICs where
   *   the size of the memory space is fixed.
   *
   * + NIOCREGIF can attach to PIPE rings sharing the same memory
   *   space with a parent device. The ifname indicates the parent device,
   *   which must already exist. Flags in nr_flags indicate if we want to
   *   bind the master or slave side, the index (from nr_ringid)
   *   is just a cookie and does not need to be sequential.
   *
   * + NIOCREGIF can also attach to 'monitor' rings that replicate
   *   the content of specific rings, also from the same memory space.
   *
   *   Extra flags in nr_flags support the above functions.
   *   Application libraries may use the following naming scheme:
   *	netmap:foo			all NIC ring pairs
   *	netmap:foo^			only host ring pair
   *	netmap:foo+			all NIC ring + host ring pairs
   *	netmap:foo-k			the k-th NIC ring pair
   *	netmap:foo{k			PIPE ring pair k, master side
   *	netmap:foo}k			PIPE ring pair k, slave side
   *
   * Some notes about host rings:
   *
   * + The RX host ring is used to store those packets that the host network
   *   stack is trying to transmit through a NIC queue, but only if that queue
   *   is currently in netmap mode. Netmap will not intercept host stack mbufs
   *   designated to NIC queues that are not in netmap mode. As a consequence,
   *   registering a netmap port with netmap:foo^ is not enough to intercept
   *   mbufs in the RX host ring; the netmap port should be registered with
   *   netmap:foo*, or another registration should be done to open at least a
   *   NIC TX queue in netmap mode.
   *
   * + Netmap is not currently able to deal with intercepted trasmit mbufs which
   *   require offloadings like TSO, UFO, checksumming offloadings, etc. It is
   *   responsibility of the user to disable those offloadings (e.g. using
   *   ifconfig on FreeBSD or ethtool -K on Linux) for an interface that is being
   *   used in netmap mode. If the offloadings are not disabled, GSO and/or
   *   unchecksummed packets may be dropped immediately or end up in the host RX
   *   ring, and will be dropped as soon as the packet reaches another netmap
   *   adapter.
   */
  
  /*
   * struct netmap_slot is a buffer descriptor
   */
  struct netmap_slot {
  	uint32_t buf_idx;	/* buffer index */
  	uint16_t len;		/* length for this slot */
  	uint16_t flags;		/* buf changed, etc. */
  	uint64_t ptr;		/* pointer for indirect buffers */
  };
  
  /*
   * The following flags control how the slot is used
   */
  
  #define	NS_BUF_CHANGED	0x0001	/* buf_idx changed */
  	/*
  	 * must be set whenever buf_idx is changed (as it might be
  	 * necessary to recompute the physical address and mapping)
  	 *
  	 * It is also set by the kernel whenever the buf_idx is
  	 * changed internally (e.g., by pipes). Applications may
  	 * use this information to know when they can reuse the
  	 * contents of previously prepared buffers.
  	 */
  
  #define	NS_REPORT	0x0002	/* ask the hardware to report results */
  	/*
  	 * Request notification when slot is used by the hardware.
  	 * Normally transmit completions are handled lazily and
  	 * may be unreported. This flag lets us know when a slot
  	 * has been sent (e.g. to terminate the sender).
  	 */
  
  #define	NS_FORWARD	0x0004	/* pass packet 'forward' */
  	/*
  	 * (Only for physical ports, rx rings with NR_FORWARD set).
  	 * Slot released to the kernel (i.e. before ring->head) with
  	 * this flag set are passed to the peer ring (host/NIC),
  	 * thus restoring the host-NIC connection for these slots.
  	 * This supports efficient traffic monitoring or firewalling.
  	 */
  
  #define	NS_NO_LEARN	0x0008	/* disable bridge learning */
   	/*
  	 * On a VALE switch, do not 'learn' the source port for
   	 * this buffer.
  	 */
  
  #define	NS_INDIRECT	0x0010	/* userspace buffer */
   	/*
  	 * (VALE tx rings only) data is in a userspace buffer,
  	 * whose address is in the 'ptr' field in the slot.
  	 */
  
  #define	NS_MOREFRAG	0x0020	/* packet has more fragments */
   	/*
  	 * (VALE ports only)
  	 * Set on all but the last slot of a multi-segment packet.
  	 * The 'len' field refers to the individual fragment.
  	 */
  
  #define	NS_PORT_SHIFT	8
  #define	NS_PORT_MASK	(0xff << NS_PORT_SHIFT)
  	/*
   	 * The high 8 bits of the flag, if not zero, indicate the
  	 * destination port for the VALE switch, overriding
   	 * the lookup table.
   	 */
  
  #define	NS_RFRAGS(_slot)	( ((_slot)->flags >> 8) & 0xff)
  	/*
  	 * (VALE rx rings only) the high 8 bits
  	 *  are the number of fragments.
  	 */
  
  
  /*
   * struct netmap_ring
   *
   * Netmap representation of a TX or RX ring (also known as "queue").
   * This is a queue implemented as a fixed-size circular array.
   * At the software level the important fields are: head, cur, tail.
   *
   * In TX rings:
   *
   *	head	first slot available for transmission.
   *	cur	wakeup point. select() and poll() will unblock
   *		when 'tail' moves past 'cur'
   *	tail	(readonly) first slot reserved to the kernel
   *
   *	[head .. tail-1] can be used for new packets to send;
   *	'head' and 'cur' must be incremented as slots are filled
   *	    with new packets to be sent;
   *	'cur' can be moved further ahead if we need more space
   *	for new transmissions. XXX todo (2014-03-12)
   *
   * In RX rings:
   *
   *	head	first valid received packet
   *	cur	wakeup point. select() and poll() will unblock
   *		when 'tail' moves past 'cur'
   *	tail	(readonly) first slot reserved to the kernel
   *
   *	[head .. tail-1] contain received packets;
   *	'head' and 'cur' must be incremented as slots are consumed
   *		and can be returned to the kernel;
   *	'cur' can be moved further ahead if we want to wait for
   *		new packets without returning the previous ones.
   *
   * DATA OWNERSHIP/LOCKING:
   *	The netmap_ring, and all slots and buffers in the range
   *	[head .. tail-1] are owned by the user program;
   *	the kernel only accesses them during a netmap system call
   *	and in the user thread context.
   *
   *	Other slots and buffers are reserved for use by the kernel
   */
  struct netmap_ring {
  	/*
  	 * buf_ofs is meant to be used through macros.
  	 * It contains the offset of the buffer region from this
  	 * descriptor.
  	 */
  	const int64_t	buf_ofs;
  	const uint32_t	num_slots;	/* number of slots in the ring. */
  	const uint32_t	nr_buf_size;
  	const uint16_t	ringid;
  	const uint16_t	dir;		/* 0: tx, 1: rx */
  
  	uint32_t        head;		/* (u) first user slot */
  	uint32_t        cur;		/* (u) wakeup point */
  	uint32_t	tail;		/* (k) first kernel slot */
  
  	uint32_t	flags;
  
  	struct timeval	ts;		/* (k) time of last *sync() */
  
  	/* opaque room for a mutex or similar object */
  #if !defined(_WIN32) || defined(__CYGWIN__)
  	uint8_t	__attribute__((__aligned__(NM_CACHE_ALIGN))) sem[128];
  #else
  	uint8_t	__declspec(align(NM_CACHE_ALIGN)) sem[128];
  #endif
  
  	/* the slots follow. This struct has variable size */
  	struct netmap_slot slot[0];	/* array of slots. */
  };
  
  
  /*
   * RING FLAGS
   */
  #define	NR_TIMESTAMP	0x0002		/* set timestamp on *sync() */
  	/*
  	 * updates the 'ts' field on each netmap syscall. This saves
  	 * saves a separate gettimeofday(), and is not much worse than
  	 * software timestamps generated in the interrupt handler.
  	 */
  
  #define	NR_FORWARD	0x0004		/* enable NS_FORWARD for ring */
   	/*
  	 * Enables the NS_FORWARD slot flag for the ring.
  	 */
  
  
  /*
   * Netmap representation of an interface and its queue(s).
   * This is initialized by the kernel when binding a file
   * descriptor to a port, and should be considered as readonly
   * by user programs. The kernel never uses it.
   *
   * There is one netmap_if for each file descriptor on which we want
   * to select/poll.
   * select/poll operates on one or all pairs depending on the value of
   * nmr_queueid passed on the ioctl.
   */
  struct netmap_if {
  	char		ni_name[IFNAMSIZ]; /* name of the interface. */
  	const uint32_t	ni_version;	/* API version, currently unused */
  	const uint32_t	ni_flags;	/* properties */
  #define	NI_PRIV_MEM	0x1		/* private memory region */
  
  	/*
  	 * The number of packet rings available in netmap mode.
  	 * Physical NICs can have different numbers of tx and rx rings.
  	 * Physical NICs also have a 'host' ring pair.
  	 * Additionally, clients can request additional ring pairs to
  	 * be used for internal communication.
  	 */
  	const uint32_t	ni_tx_rings;	/* number of HW tx rings */
  	const uint32_t	ni_rx_rings;	/* number of HW rx rings */
  
  	uint32_t	ni_bufs_head;	/* head index for extra bufs */
  	uint32_t	ni_spare1[5];
  	/*
  	 * The following array contains the offset of each netmap ring
  	 * from this structure, in the following order:
  	 * NIC tx rings (ni_tx_rings); host tx ring (1); extra tx rings;
  	 * NIC rx rings (ni_rx_rings); host tx ring (1); extra rx rings.
  	 *
  	 * The area is filled up by the kernel on NIOCREGIF,
  	 * and then only read by userspace code.
  	 */
  	const ssize_t	ring_ofs[0];
  };
  
  
  #ifndef NIOCREGIF
  /*
   * ioctl names and related fields
   *
   * NIOCTXSYNC, NIOCRXSYNC synchronize tx or rx queues,
   *	whose identity is set in NIOCREGIF through nr_ringid.
   *	These are non blocking and take no argument.
   *
   * NIOCGINFO takes a struct ifreq, the interface name is the input,
   *	the outputs are number of queues and number of descriptor
   *	for each queue (useful to set number of threads etc.).
   *	The info returned is only advisory and may change before
   *	the interface is bound to a file descriptor.
   *
   * NIOCREGIF takes an interface name within a struct nmre,
   *	and activates netmap mode on the interface (if possible).
   *
   * The argument to NIOCGINFO/NIOCREGIF overlays struct ifreq so we
   * can pass it down to other NIC-related ioctls.
   *
   * The actual argument (struct nmreq) has a number of options to request
   * different functions.
   * The following are used in NIOCREGIF when nr_cmd == 0:
   *
   * nr_name	(in)
   *	The name of the port (em0, valeXXX:YYY, etc.)
   *	limited to IFNAMSIZ for backward compatibility.
   *
   * nr_version	(in/out)
   *	Must match NETMAP_API as used in the kernel, error otherwise.
   *	Always returns the desired value on output.
   *
   * nr_tx_slots, nr_tx_slots, nr_tx_rings, nr_rx_rings (in/out)
   *	On input, non-zero values may be used to reconfigure the port
   *	according to the requested values, but this is not guaranteed.
   *	On output the actual values in use are reported.
   *
   * nr_ringid (in)
   *	Indicates how rings should be bound to the file descriptors.
   *	If nr_flags != 0, then the low bits (in NETMAP_RING_MASK)
   *	are used to indicate the ring number, and nr_flags specifies
   *	the actual rings to bind. NETMAP_NO_TX_POLL is unaffected.
   *
   *	NOTE: THE FOLLOWING (nr_flags == 0) IS DEPRECATED:
   *	If nr_flags == 0, NETMAP_HW_RING and NETMAP_SW_RING control
   *	the binding as follows:
   *	0 (default)			binds all physical rings
   *	NETMAP_HW_RING | ring number	binds a single ring pair
   *	NETMAP_SW_RING			binds only the host tx/rx rings
   *
   *	NETMAP_NO_TX_POLL can be OR-ed to make select()/poll() push
   *		packets on tx rings only if POLLOUT is set.
   *		The default is to push any pending packet.
   *
   *	NETMAP_DO_RX_POLL can be OR-ed to make select()/poll() release
   *		packets on rx rings also when POLLIN is NOT set.
   *		The default is to touch the rx ring only with POLLIN.
   *		Note that this is the opposite of TX because it
   *		reflects the common usage.
   *
   *	NOTE: NETMAP_PRIV_MEM IS DEPRECATED, use nr_arg2 instead.
   *	NETMAP_PRIV_MEM is set on return for ports that do not use
   *		the global memory allocator.
   *		This information is not significant and applications
   *		should look at the region id in nr_arg2
   *
   * nr_flags	is the recommended mode to indicate which rings should
   *		be bound to a file descriptor. Values are NR_REG_*
   *
   * nr_arg1 (in)	The number of extra rings to be reserved.
   *		Especially when allocating a VALE port the system only
   *		allocates the amount of memory needed for the port.
   *		If more shared memory rings are desired (e.g. for pipes),
   *		the first invocation for the same basename/allocator
   *		should specify a suitable number. Memory cannot be
   *		extended after the first allocation without closing
   *		all ports on the same region.
   *
   * nr_arg2 (in/out) The identity of the memory region used.
   *		On input, 0 means the system decides autonomously,
   *		other values may try to select a specific region.
   *		On return the actual value is reported.
   *		Region '1' is the global allocator, normally shared
   *		by all interfaces. Other values are private regions.
   *		If two ports the same region zero-copy is possible.
   *
   * nr_arg3 (in/out)	number of extra buffers to be allocated.
   *
   *
   *
   * nr_cmd (in)	if non-zero indicates a special command:
   *	NETMAP_BDG_ATTACH	 and nr_name = vale*:ifname
   *		attaches the NIC to the switch; nr_ringid specifies
   *		which rings to use. Used by vale-ctl -a ...
   *	    nr_arg1 = NETMAP_BDG_HOST also attaches the host port
   *		as in vale-ctl -h ...
   *
   *	NETMAP_BDG_DETACH	and nr_name = vale*:ifname
   *		disconnects a previously attached NIC.
   *		Used by vale-ctl -d ...
   *
   *	NETMAP_BDG_LIST
   *		list the configuration of VALE switches.
   *
   *	NETMAP_BDG_VNET_HDR
   *		Set the virtio-net header length used by the client
   *		of a VALE switch port.
   *
   *	NETMAP_BDG_NEWIF
   *		create a persistent VALE port with name nr_name.
   *		Used by vale-ctl -n ...
   *
   *	NETMAP_BDG_DELIF
   *		delete a persistent VALE port. Used by vale-ctl -d ...
   *
   * nr_arg1, nr_arg2, nr_arg3  (in/out)		command specific
   *
   *
   *
   */
  
  
  /*
   * struct nmreq overlays a struct ifreq (just the name)
   */
  struct nmreq {
  	char		nr_name[IFNAMSIZ];
  	uint32_t	nr_version;	/* API version */
  	uint32_t	nr_offset;	/* nifp offset in the shared region */
  	uint32_t	nr_memsize;	/* size of the shared region */
  	uint32_t	nr_tx_slots;	/* slots in tx rings */
  	uint32_t	nr_rx_slots;	/* slots in rx rings */
  	uint16_t	nr_tx_rings;	/* number of tx rings */
  	uint16_t	nr_rx_rings;	/* number of rx rings */
  
  	uint16_t	nr_ringid;	/* ring(s) we care about */
  #define NETMAP_HW_RING		0x4000	/* single NIC ring pair */
  #define NETMAP_SW_RING		0x2000	/* only host ring pair */
  
  #define NETMAP_RING_MASK	0x0fff	/* the ring number */
  
  #define NETMAP_NO_TX_POLL	0x1000	/* no automatic txsync on poll */
  
  #define NETMAP_DO_RX_POLL	0x8000	/* DO automatic rxsync on poll */
  
  	uint16_t	nr_cmd;
  #define NETMAP_BDG_ATTACH	1	/* attach the NIC */
  #define NETMAP_BDG_DETACH	2	/* detach the NIC */
  #define NETMAP_BDG_REGOPS	3	/* register bridge callbacks */
  #define NETMAP_BDG_LIST		4	/* get bridge's info */
  #define NETMAP_BDG_VNET_HDR     5       /* set the port virtio-net-hdr length */
  #define NETMAP_BDG_OFFSET	NETMAP_BDG_VNET_HDR	/* deprecated alias */
  #define NETMAP_BDG_NEWIF	6	/* create a virtual port */
  #define NETMAP_BDG_DELIF	7	/* destroy a virtual port */
  #define NETMAP_PT_HOST_CREATE	8	/* create ptnetmap kthreads */
  #define NETMAP_PT_HOST_DELETE	9	/* delete ptnetmap kthreads */
  #define NETMAP_BDG_POLLING_ON	10	/* delete polling kthread */
  #define NETMAP_BDG_POLLING_OFF	11	/* delete polling kthread */
  #define NETMAP_VNET_HDR_GET	12      /* get the port virtio-net-hdr length */
  #define NETMAP_POOLS_INFO_GET	13	/* get memory allocator pools info */
  	uint16_t	nr_arg1;	/* reserve extra rings in NIOCREGIF */
  #define NETMAP_BDG_HOST		1	/* attach the host stack on ATTACH */
  
  	uint16_t	nr_arg2;
  	uint32_t	nr_arg3;	/* req. extra buffers in NIOCREGIF */
  	uint32_t	nr_flags;
  	/* various modes, extends nr_ringid */
  	uint32_t	spare2[1];
  };
  
  #define NR_REG_MASK		0xf /* values for nr_flags */
  enum {	NR_REG_DEFAULT	= 0,	/* backward compat, should not be used. */
  	NR_REG_ALL_NIC	= 1,
  	NR_REG_SW	= 2,
  	NR_REG_NIC_SW	= 3,
  	NR_REG_ONE_NIC	= 4,
  	NR_REG_PIPE_MASTER = 5,
  	NR_REG_PIPE_SLAVE = 6,
  };
  /* monitor uses the NR_REG to select the rings to monitor */
  #define NR_MONITOR_TX	0x100
  #define NR_MONITOR_RX	0x200
  #define NR_ZCOPY_MON	0x400
  /* request exclusive access to the selected rings */
  #define NR_EXCLUSIVE	0x800
  /* request ptnetmap host support */
  #define NR_PASSTHROUGH_HOST	NR_PTNETMAP_HOST /* deprecated */
  #define NR_PTNETMAP_HOST	0x1000
  #define NR_RX_RINGS_ONLY	0x2000
  #define NR_TX_RINGS_ONLY	0x4000
  /* Applications set this flag if they are able to deal with virtio-net headers,
   * that is send/receive frames that start with a virtio-net header.
   * If not set, NIOCREGIF will fail with netmap ports that require applications
   * to use those headers. If the flag is set, the application can use the
   * NETMAP_VNET_HDR_GET command to figure out the header length. */
  #define NR_ACCEPT_VNET_HDR	0x8000
  
  #define	NM_BDG_NAME		"vale"	/* prefix for bridge port name */
  
  /*
   * Windows does not have _IOWR(). _IO(), _IOW() and _IOR() are defined
   * in ws2def.h but not sure if they are in the form we need.
   * XXX so we redefine them
   * in a convenient way to use for DeviceIoControl signatures
   */
  #ifdef _WIN32
  #undef _IO	// ws2def.h
  #define _WIN_NM_IOCTL_TYPE 40000
  #define _IO(_c, _n)	CTL_CODE(_WIN_NM_IOCTL_TYPE, ((_n) + 0x800) , \
  		METHOD_BUFFERED, FILE_ANY_ACCESS  )
  #define _IO_direct(_c, _n)	CTL_CODE(_WIN_NM_IOCTL_TYPE, ((_n) + 0x800) , \
  		METHOD_OUT_DIRECT, FILE_ANY_ACCESS  )
  
  #define _IOWR(_c, _n, _s)	_IO(_c, _n)
  
  /* We havesome internal sysctl in addition to the externally visible ones */
  #define NETMAP_MMAP _IO_direct('i', 160)	// note METHOD_OUT_DIRECT
  #define NETMAP_POLL _IO('i', 162)
  
  /* and also two setsockopt for sysctl emulation */
  #define NETMAP_SETSOCKOPT _IO('i', 140)
  #define NETMAP_GETSOCKOPT _IO('i', 141)
  
  
  //These linknames are for the Netmap Core Driver
  #define NETMAP_NT_DEVICE_NAME			L"\\Device\\NETMAP"
  #define NETMAP_DOS_DEVICE_NAME			L"\\DosDevices\\netmap"
  
  //Definition of a structure used to pass a virtual address within an IOCTL
  typedef struct _MEMORY_ENTRY {
  	PVOID       pUsermodeVirtualAddress;
  } MEMORY_ENTRY, *PMEMORY_ENTRY;
  
  typedef struct _POLL_REQUEST_DATA {
  	int events;
  	int timeout;
  	int revents;
  } POLL_REQUEST_DATA;
  
  #endif /* _WIN32 */
  
  /*
   * FreeBSD uses the size value embedded in the _IOWR to determine
   * how much to copy in/out. So we need it to match the actual
   * data structure we pass. We put some spares in the structure
   * to ease compatibility with other versions
   */
  #define NIOCGINFO	_IOWR('i', 145, struct nmreq) /* return IF info */
  #define NIOCREGIF	_IOWR('i', 146, struct nmreq) /* interface register */
  #define NIOCTXSYNC	_IO('i', 148) /* sync tx queues */
  #define NIOCRXSYNC	_IO('i', 149) /* sync rx queues */
  #define NIOCCONFIG	_IOWR('i',150, struct nm_ifreq) /* for ext. modules */
  #endif /* !NIOCREGIF */
  
  
  /*
   * Helper functions for kernel and userspace
   */
  
  /*
   * check if space is available in the ring.
   */
  static inline int
  nm_ring_empty(struct netmap_ring *ring)
  {
  	return (ring->cur == ring->tail);
  }
  
  /*
   * Opaque structure that is passed to an external kernel
   * module via ioctl(fd, NIOCCONFIG, req) for a user-owned
   * bridge port (at this point ephemeral VALE interface).
   */
  #define NM_IFRDATA_LEN 256
  struct nm_ifreq {
  	char nifr_name[IFNAMSIZ];
  	char data[NM_IFRDATA_LEN];
  };
  
  #endif /* _NET_NETMAP_H_ */
  