FreeBSD/Linux Kernel Cross Reference
sys/net/netmap.h

     /*
      * 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: releng/11.1/sys/net/netmap.h 285349 2015-07-10 05:51:36Z 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 */
           uint8_t         sem[128] __attribute__((__aligned__(NM_CACHE_ALIGN)));
   
           /* 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 */
           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
   
   
   /*
    * 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_ */

Cache object: 40e8f875d06b7b1ead5aa418003375b8