64ae02c365
USERSPACE: 1. add support for devices with different number of rx and tx queues; 2. add better support for zero-copy operation, adding an extra field to the netmap ring to indicate how many buffers we have already processed but not yet released (with help from Eddie Kohler); 3. The two changes above unfortunately require an API change, so while at it add a version field and some spares to the ioctl() argument to help detect mismatches. 4. update the manual page for the two changes above; 5. update sample applications in tools/tools/netmap KERNEL: 1. simplify the internal structures moving the global wait queues to the 'struct netmap_adapter'; 2. simplify the functions that map kring<->nic ring indexes 3. normalize device-specific code, helps mainteinance; 4. start exploring the impact of micro-optimizations (prefetch etc.) in the ixgbe driver. Use 'legacy' descriptors on the tx ring and prefetch slots gives about 20% speedup at 900 MHz. Another 7-10% would come from removing the explict calls to bus_dmamap* in the core (they are effectively NOPs in this case, but it takes expensive load of the per-buffer dma maps to figure out that they are all NULL. Rx performance not investigated. I am postponing the MFC so i can import a few more improvements before merging.
294 lines
12 KiB
C
294 lines
12 KiB
C
/*
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* Copyright (C) 2011 Matteo Landi, Luigi Rizzo. All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions are
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* met:
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*
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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*
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the
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* distribution.
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*
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* 3. Neither the name of the authors nor the names of their contributors
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* may be used to endorse or promote products derived from this
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* software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY MATTEO LANDI AND CONTRIBUTORS "AS IS" AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL MATTEO LANDI OR CONTRIBUTORS
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* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
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* THE POSSIBILITY OF SUCH DAMAGE.
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*/
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/*
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* $FreeBSD$
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* $Id: netmap.h 10601 2012-02-21 16:40:14Z luigi $
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*
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* Definitions of constants and the structures used by the netmap
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* framework, for the part visible to both kernel and userspace.
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* Detailed info on netmap is available with "man netmap" or at
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*
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* http://info.iet.unipi.it/~luigi/netmap/
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*/
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#ifndef _NET_NETMAP_H_
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#define _NET_NETMAP_H_
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/*
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* --- Netmap data structures ---
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*
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* The data structures used by netmap are shown below. Those in
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* capital letters are in an mmapp()ed area shared with userspace,
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* while others are private to the kernel.
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* Shared structures do not contain pointers but only memory
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* offsets, so that addressing is portable between kernel and userspace.
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softc
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+----------------+
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| standard fields|
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| if_pspare[0] ----------+
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+----------------+ |
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+----------------+<------+
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|(netmap_adapter)|
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| | netmap_kring
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| tx_rings *--------------------------------->+---------------+
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| | netmap_kring | ring *---------.
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| rx_rings *--------->+---------------+ | nr_hwcur | |
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+----------------+ | ring *--------. | nr_hwavail | V
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| nr_hwcur | | | selinfo | |
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| nr_hwavail | | +---------------+ .
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| selinfo | | | ... | .
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+---------------+ | |(ntx+1 entries)|
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| .... | | | |
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|(nrx+1 entries)| | +---------------+
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| | |
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KERNEL +---------------+ |
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====================================================================
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USERSPACE | NETMAP_RING
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+---->+-------------+
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/ | cur |
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NETMAP_IF (nifp, one per file desc.) / | avail |
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+---------------+ / | buf_ofs |
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| ni_num_queues | / +=============+
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| | / | buf_idx | slot[0]
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| | / | len, flags |
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| | / +-------------+
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+===============+ / | buf_idx | slot[1]
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| txring_ofs[0] | (rel.to nifp)--' | len, flags |
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| txring_ofs[1] | +-------------+
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(num_rings+1 entries) (nr_num_slots entries)
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| txring_ofs[n] | | buf_idx | slot[n-1]
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+---------------+ | len, flags |
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| rxring_ofs[0] | +-------------+
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| rxring_ofs[1] |
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(num_rings+1 entries)
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| txring_ofs[n] |
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+---------------+
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* The private descriptor ('softc' or 'adapter') of each interface
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* is extended with a "struct netmap_adapter" containing netmap-related
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* info (see description in dev/netmap/netmap_kernel.h.
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* Among other things, tx_rings and rx_rings point to the arrays of
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* "struct netmap_kring" which in turn reache the various
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* "struct netmap_ring", shared with userspace.
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* The NETMAP_RING is the userspace-visible replica of the NIC ring.
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* Each slot has the index of a buffer, its length and some flags.
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* In user space, the buffer address is computed as
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* (char *)ring + buf_ofs + index*NETMAP_BUF_SIZE
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* In the kernel, buffers do not necessarily need to be contiguous,
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* and the virtual and physical addresses are derived through
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* a lookup table.
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* To associate a different buffer to a slot, applications must
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* write the new index in buf_idx, and set NS_BUF_CHANGED flag to
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* make sure that the kernel updates the hardware ring as needed.
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*
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* Normally the driver is not requested to report the result of
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* transmissions (this can dramatically speed up operation).
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* However the user may request to report completion by setting
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* NS_REPORT.
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*/
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struct netmap_slot {
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uint32_t buf_idx; /* buffer index */
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uint16_t len; /* packet length, to be copied to/from the hw ring */
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uint16_t flags; /* buf changed, etc. */
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#define NS_BUF_CHANGED 0x0001 /* must resync the map, buffer changed */
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#define NS_REPORT 0x0002 /* ask the hardware to report results
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* e.g. by generating an interrupt
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*/
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};
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/*
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* Netmap representation of a TX or RX ring (also known as "queue").
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* This is a queue implemented as a fixed-size circular array.
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* At the software level, two fields are important: avail and cur.
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*
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* In TX rings:
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* avail indicates the number of slots available for transmission.
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* It is updated by the kernel after every netmap system call.
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* It MUST BE decremented by the application when it appends a
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* packet.
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* cur indicates the slot to use for the next packet
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* to send (i.e. the "tail" of the queue).
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* It MUST BE incremented by the application before
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* netmap system calls to reflect the number of newly
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* sent packets.
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* It is checked by the kernel on netmap system calls
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* (normally unmodified by the kernel unless invalid).
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*
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* The kernel side of netmap uses two additional fields in its own
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* private ring structure, netmap_kring:
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* nr_hwcur is a copy of nr_cur on an NIOCTXSYNC.
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* nr_hwavail is the number of slots known as available by the
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* hardware. It is updated on an INTR (inc by the
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* number of packets sent) and on a NIOCTXSYNC
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* (decrease by nr_cur - nr_hwcur)
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* A special case, nr_hwavail is -1 if the transmit
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* side is idle (no pending transmits).
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*
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* In RX rings:
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* avail is the number of packets available (possibly 0).
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* It MUST BE decremented by the application when it consumes
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* a packet, and it is updated to nr_hwavail on a NIOCRXSYNC
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* cur indicates the first slot that contains a packet not
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* processed yet (the "head" of the queue).
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* It MUST BE incremented by the software when it consumes
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* a packet.
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* reserved indicates the number of buffers before 'cur'
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* that the application has still in use. Normally 0,
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* it MUST BE incremented by the application when it
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* does not return the buffer immediately, and decremented
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* when the buffer is finally freed.
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*
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* The kernel side of netmap uses two additional fields in the kring:
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* nr_hwcur is a copy of nr_cur on an NIOCRXSYNC
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* nr_hwavail is the number of packets available. It is updated
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* on INTR (inc by the number of new packets arrived)
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* and on NIOCRXSYNC (decreased by nr_cur - nr_hwcur).
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*
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* DATA OWNERSHIP/LOCKING:
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* The netmap_ring is owned by the user program and it is only
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* accessed or modified in the upper half of the kernel during
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* a system call.
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*
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* The netmap_kring is only modified by the upper half of the kernel.
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*/
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struct netmap_ring {
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/*
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* nr_buf_base_ofs is meant to be used through macros.
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* It contains the offset of the buffer region from this
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* descriptor.
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*/
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const ssize_t buf_ofs;
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const uint32_t num_slots; /* number of slots in the ring. */
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uint32_t avail; /* number of usable slots */
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uint32_t cur; /* 'current' r/w position */
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uint32_t reserved; /* not refilled before current */
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const uint16_t nr_buf_size;
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uint16_t flags;
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#define NR_TIMESTAMP 0x0002 /* set timestamp on *sync() */
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struct timeval ts; /* time of last *sync() */
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/* the slots follow. This struct has variable size */
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struct netmap_slot slot[0]; /* array of slots. */
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};
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/*
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* Netmap representation of an interface and its queue(s).
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* There is one netmap_if for each file descriptor on which we want
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* to select/poll. We assume that on each interface has the same number
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* of receive and transmit queues.
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* select/poll operates on one or all pairs depending on the value of
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* nmr_queueid passed on the ioctl.
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*/
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struct netmap_if {
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char ni_name[IFNAMSIZ]; /* name of the interface. */
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const u_int ni_version; /* API version, currently unused */
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const u_int ni_rx_queues; /* number of rx queue pairs */
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const u_int ni_tx_queues; /* if zero, same as ni_tx_queues */
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/*
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* The following array contains the offset of each netmap ring
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* from this structure. The first ni_tx_queues+1 entries refer
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* to the tx rings, the next ni_rx_queues+1 refer to the rx rings
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* (the last entry in each block refers to the host stack rings).
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* The area is filled up by the kernel on NIOCREG,
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* and then only read by userspace code.
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*/
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const ssize_t ring_ofs[0];
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};
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#ifndef IFCAP_NETMAP
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#define IFCAP_NETMAP 0x100000 /* used on linux */
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#endif
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#ifndef NIOCREGIF
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/*
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* ioctl names and related fields
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*
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* NIOCGINFO takes a struct ifreq, the interface name is the input,
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* the outputs are number of queues and number of descriptor
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* for each queue (useful to set number of threads etc.).
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*
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* NIOCREGIF takes an interface name within a struct ifreq,
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* and activates netmap mode on the interface (if possible).
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*
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* NIOCUNREGIF unregisters the interface associated to the fd.
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*
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* NIOCTXSYNC, NIOCRXSYNC synchronize tx or rx queues,
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* whose identity is set in NIOCREGIF through nr_ringid
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*/
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/*
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* struct nmreq overlays a struct ifreq
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*/
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struct nmreq {
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char nr_name[IFNAMSIZ];
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uint32_t nr_version; /* API version */
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#define NETMAP_API 2 /* current version */
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uint32_t nr_offset; /* nifp offset in the shared region */
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uint32_t nr_memsize; /* size of the shared region */
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uint32_t nr_tx_slots; /* slots in tx rings */
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uint32_t nr_rx_slots; /* slots in rx rings */
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uint16_t nr_tx_rings; /* number of tx rings */
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uint16_t nr_rx_rings; /* number of rx rings */
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uint16_t nr_ringid; /* ring(s) we care about */
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#define NETMAP_HW_RING 0x4000 /* low bits indicate one hw ring */
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#define NETMAP_SW_RING 0x2000 /* process the sw ring */
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#define NETMAP_NO_TX_POLL 0x1000 /* no automatic txsync on poll */
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#define NETMAP_RING_MASK 0xfff /* the ring number */
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uint16_t spare1;
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uint32_t spare2[4];
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};
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/*
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* FreeBSD uses the size value embedded in the _IOWR to determine
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* how much to copy in/out. So we need it to match the actual
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* data structure we pass. We put some spares in the structure
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* to ease compatibility with other versions
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*/
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#define NIOCGINFO _IOWR('i', 145, struct nmreq) /* return IF info */
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#define NIOCREGIF _IOWR('i', 146, struct nmreq) /* interface register */
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#define NIOCUNREGIF _IO('i', 147) /* interface unregister */
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#define NIOCTXSYNC _IO('i', 148) /* sync tx queues */
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#define NIOCRXSYNC _IO('i', 149) /* sync rx queues */
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#endif /* !NIOCREGIF */
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#endif /* _NET_NETMAP_H_ */
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