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| Current File : //sys/net/netmap.h |
/*
* Copyright (C) 2011 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.
*
* 3. Neither the name of the authors nor the names of their contributors
* may be used to endorse or promote products derived from this
* software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY MATTEO LANDI AND CONTRIBUTORS "AS 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 MATTEO LANDI 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: release/9.1.0/sys/net/netmap.h 235549 2012-05-17 15:02:51Z luigi $
* $Id: netmap.h 10601 2012-02-21 16:40:14Z 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/
*/
#ifndef _NET_NETMAP_H_
#define _NET_NETMAP_H_
/*
* --- Netmap data structures ---
*
* The data structures used by netmap are shown below. Those in
* capital letters are in an mmapp()ed area shared with userspace,
* while others are private to the kernel.
* Shared structures do not contain pointers but only memory
* offsets, so that addressing is portable between kernel and userspace.
softc
+----------------+
| standard fields|
| if_pspare[0] ----------+
+----------------+ |
|
+----------------+<------+
|(netmap_adapter)|
| | netmap_kring
| tx_rings *--------------------------------->+---------------+
| | netmap_kring | ring *---------.
| rx_rings *--------->+---------------+ | nr_hwcur | |
+----------------+ | ring *--------. | nr_hwavail | V
| nr_hwcur | | | selinfo | |
| nr_hwavail | | +---------------+ .
| selinfo | | | ... | .
+---------------+ | |(ntx+1 entries)|
| .... | | | |
|(nrx+1 entries)| | +---------------+
| | |
KERNEL +---------------+ |
|
====================================================================
|
USERSPACE | NETMAP_RING
+---->+-------------+
/ | cur |
NETMAP_IF (nifp, one per file desc.) / | avail |
+---------------+ / | buf_ofs |
| ni_tx_rings | / +=============+
| ni_rx_rings | / | buf_idx | slot[0]
| | / | len, flags |
| | / +-------------+
+===============+ / | buf_idx | slot[1]
| txring_ofs[0] | (rel.to nifp)--' | len, flags |
| txring_ofs[1] | +-------------+
(num_rings+1 entries) (nr_num_slots entries)
| txring_ofs[n] | | buf_idx | slot[n-1]
+---------------+ | len, flags |
| rxring_ofs[0] | +-------------+
| rxring_ofs[1] |
(num_rings+1 entries)
| txring_ofs[n] |
+---------------+
* The private descriptor ('softc' or 'adapter') of each interface
* is extended with a "struct netmap_adapter" containing netmap-related
* info (see description in dev/netmap/netmap_kernel.h.
* Among other things, tx_rings and rx_rings point to the arrays of
* "struct netmap_kring" which in turn reache the various
* "struct netmap_ring", shared with userspace.
* The NETMAP_RING is the userspace-visible replica of the NIC ring.
* Each slot has the index of a buffer, its length and some flags.
* In user space, the buffer address is computed as
* (char *)ring + buf_ofs + index*NETMAP_BUF_SIZE
* In the kernel, buffers do not necessarily need to be contiguous,
* and the virtual and physical addresses are derived through
* a lookup table.
* To associate a different buffer to a slot, applications must
* write the new index in buf_idx, and set NS_BUF_CHANGED flag to
* make sure that the kernel updates the hardware ring as needed.
*
* Normally the driver is not requested to report the result of
* transmissions (this can dramatically speed up operation).
* However the user may request to report completion by setting
* NS_REPORT.
*/
struct netmap_slot {
uint32_t buf_idx; /* buffer index */
uint16_t len; /* packet length, to be copied to/from the hw ring */
uint16_t flags; /* buf changed, etc. */
#define NS_BUF_CHANGED 0x0001 /* must resync the map, buffer changed */
#define NS_REPORT 0x0002 /* ask the hardware to report results
* e.g. by generating an interrupt
*/
};
/*
* 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, two fields are important: avail and cur.
*
* In TX rings:
* avail indicates the number of slots available for transmission.
* It is updated by the kernel after every netmap system call.
* It MUST BE decremented by the application when it appends a
* packet.
* cur indicates the slot to use for the next packet
* to send (i.e. the "tail" of the queue).
* It MUST BE incremented by the application before
* netmap system calls to reflect the number of newly
* sent packets.
* It is checked by the kernel on netmap system calls
* (normally unmodified by the kernel unless invalid).
*
* The kernel side of netmap uses two additional fields in its own
* private ring structure, netmap_kring:
* nr_hwcur is a copy of nr_cur on an NIOCTXSYNC.
* nr_hwavail is the number of slots known as available by the
* hardware. It is updated on an INTR (inc by the
* number of packets sent) and on a NIOCTXSYNC
* (decrease by nr_cur - nr_hwcur)
* A special case, nr_hwavail is -1 if the transmit
* side is idle (no pending transmits).
*
* In RX rings:
* avail is the number of packets available (possibly 0).
* It MUST BE decremented by the application when it consumes
* a packet, and it is updated to nr_hwavail on a NIOCRXSYNC
* cur indicates the first slot that contains a packet not
* processed yet (the "head" of the queue).
* It MUST BE incremented by the software when it consumes
* a packet.
* reserved indicates the number of buffers before 'cur'
* that the application has still in use. Normally 0,
* it MUST BE incremented by the application when it
* does not return the buffer immediately, and decremented
* when the buffer is finally freed.
*
* The kernel side of netmap uses two additional fields in the kring:
* nr_hwcur is a copy of nr_cur on an NIOCRXSYNC
* nr_hwavail is the number of packets available. It is updated
* on INTR (inc by the number of new packets arrived)
* and on NIOCRXSYNC (decreased by nr_cur - nr_hwcur).
*
* DATA OWNERSHIP/LOCKING:
* The netmap_ring is owned by the user program and it is only
* accessed or modified in the upper half of the kernel during
* a system call.
*
* The netmap_kring is only modified by the upper half of the kernel.
*/
struct netmap_ring {
/*
* nr_buf_base_ofs is meant to be used through macros.
* It contains the offset of the buffer region from this
* descriptor.
*/
const ssize_t buf_ofs;
const uint32_t num_slots; /* number of slots in the ring. */
uint32_t avail; /* number of usable slots */
uint32_t cur; /* 'current' r/w position */
uint32_t reserved; /* not refilled before current */
const uint16_t nr_buf_size;
uint16_t flags;
#define NR_TIMESTAMP 0x0002 /* set timestamp on *sync() */
struct timeval ts; /* time of last *sync() */
/* the slots follow. This struct has variable size */
struct netmap_slot slot[0]; /* array of slots. */
};
/*
* Netmap representation of an interface and its queue(s).
* There is one netmap_if for each file descriptor on which we want
* to select/poll. We assume that on each interface has the same number
* of receive and transmit queues.
* 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 u_int ni_version; /* API version, currently unused */
const u_int ni_rx_rings; /* number of rx rings */
const u_int ni_tx_rings; /* if zero, same as ni_rx_rings */
/*
* The following array contains the offset of each netmap ring
* from this structure. The first ni_tx_queues+1 entries refer
* to the tx rings, the next ni_rx_queues+1 refer to the rx rings
* (the last entry in each block refers to the host stack rings).
* The area is filled up by the kernel on NIOCREG,
* and then only read by userspace code.
*/
const ssize_t ring_ofs[0];
};
#ifndef NIOCREGIF
/*
* ioctl names and related fields
*
* 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.).
*
* NIOCREGIF takes an interface name within a struct ifreq,
* and activates netmap mode on the interface (if possible).
*
* NIOCUNREGIF unregisters the interface associated to the fd.
*
* NIOCTXSYNC, NIOCRXSYNC synchronize tx or rx queues,
* whose identity is set in NIOCREGIF through nr_ringid
*/
/*
* struct nmreq overlays a struct ifreq
*/
struct nmreq {
char nr_name[IFNAMSIZ];
uint32_t nr_version; /* API version */
#define NETMAP_API 3 /* current 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 /* low bits indicate one hw ring */
#define NETMAP_SW_RING 0x2000 /* process the sw ring */
#define NETMAP_NO_TX_POLL 0x1000 /* no automatic txsync on poll */
#define NETMAP_RING_MASK 0xfff /* the ring number */
uint16_t spare1;
uint32_t spare2[4];
};
/*
* 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 NIOCUNREGIF _IO('i', 147) /* interface unregister */
#define NIOCTXSYNC _IO('i', 148) /* sync tx queues */
#define NIOCRXSYNC _IO('i', 149) /* sync rx queues */
#endif /* !NIOCREGIF */
#endif /* _NET_NETMAP_H_ */