netmap: Reinstate and update netmap plugin

Thet netmap plugin was moved to depreciated in commit 998b8fe.

On FreeBSD netmap offers a natively supported kernel interface for
userspace networking and enables VPP without the use of DPDK.

Reinstate the netmap plugin and adapt it to the newer plugin interface.

Type: improvement
Change-Id: I113daa33a490f04cbb29909f9789fa66284ac80e
Signed-off-by: Tom Jones <thj@freebsd.org>

1 files changed, 650 insertions, 0 deletions

diff --git a/src/plugins/netmap/net_netmap.h b/src/plugins/netmap/net_netmap.h
new file mode 100644
index 00000000000..ecccedd4484
--- /dev/null
+++ b/src/plugins/netmap/net_netmap.h
@@ -0,0 +1,650 @@
+/*
+ * 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 14 /* current API version */
+
+#define NETMAP_MIN_API 14 /* 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
+ */
+
+/*
+ * 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 */
+	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
+
+
+/*
+ * 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];
+};
+
+/*
+ * netmap kernel thread configuration
+ */
+/* bhyve/vmm.ko MSIX parameters for IOCTL */
+struct ptn_vmm_ioctl_msix {
+	uint64_t        msg;
+	uint64_t        addr;
+};
+
+/* IOCTL parameters */
+struct nm_kth_ioctl {
+	u_long				com;
+	/* TODO: use union */
+	union {
+		struct ptn_vmm_ioctl_msix msix;
+	} data;
+};
+
+/* Configuration of a ptnetmap ring */
+struct ptnet_ring_cfg {
+	uint64_t ioeventfd;		/* eventfd in linux, tsleep() parameter in FreeBSD */
+	uint64_t irqfd;			/* eventfd in linux, ioctl fd in FreeBSD */
+	struct nm_kth_ioctl ioctl;	/* ioctl parameter to send irq (only used in bhyve/FreeBSD) */
+};
+#endif /* _NET_NETMAP_H_ */