net_netmap.h

Go to the documentation of this file.

/*
 * 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
 */

/*
 * 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_ */