/*-
* SPDX-License-Identifier: BSD-2-Clause
*
* 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.
*/
/*
*
* 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+htx entries) (num_slots entries)
| txring_ofs[t] | | buf_idx, len | slot[n-1]
+----------------+ | flags, ptr |
| rxring_ofs[0] | +---------------+
| rxring_ofs[1] |
(rx+hrx 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 at least one tx/rx ring
* pair attached to the host stack (these pairs are 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 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 rings pairs
* netmap:foo^ only host rings pairs
* netmap:foo^k the k-th host rings pair
* netmap:foo+ all NIC rings + host rings pairs
* netmap:foo-k the k-th NIC rings pair
* netmap:foo{k PIPE rings pair k, master side
* netmap:foo}k PIPE rings pair k, slave side
*
* Some notes about host rings:
*
* + The RX host rings are used to store those packets that the host network
* stack is trying to transmit through a NIC queue, but only if that queue
* is currently in netmap mode. Netmap will not intercept host stack mbufs
* designated to NIC queues that are not in netmap mode. As a consequence,
* registering a netmap port with netmap:foo^ is not enough to intercept
* mbufs in the RX host rings; the netmap port should be registered with
* netmap:foo*, or another registration should be done to open at least a
* NIC TX queue in netmap mode.
*
* + Netmap is not currently able to deal with intercepted transmit mbufs which
* require offloadings like TSO, UFO, checksumming offloadings, etc. It is
* responsibility of the user to disable those offloadings (e.g. using
* ifconfig on FreeBSD or ethtool -K on Linux) for an interface that is being
* used in netmap mode. If the offloadings are not disabled, GSO and/or
* unchecksummed packets may be dropped immediately or end up in the host RX
* rings, and will be dropped as soon as the packet reaches another netmap
* adapter.
*/
/*
* 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, ptnetmap ports and some NIC ports, e.g.
* ixgbe and i40e on Linux)
* Set on all but the last slot of a multi-segment packet.
* The 'len' field refers to the individual fragment.
*/
#define NS_TXMON 0x0040
/* (monitor ports only) the packet comes from the TX
* ring of the monitored port
*/
#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.
*/
#define NETMAP_MAX_FRAGS 64 /* max 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() */
/* offset_mask is used to isolate the part of the ptr field
* in the slots used to contain an offset in the buffer.
* It is zero if the ring has not be opened using the
* NETMAP_REQ_OPT_OFFSETS option.
*/
const uint64_t offset_mask;
/* the alignment requirement, in bytes, for the start
* of the packets inside the buffers.
* User programs should take this alignment into
* account when specifying buffer-offsets in TX slots.
*/
const uint64_t buf_align;
/* 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.
*/
/*
* Helper functions for kernel and userspace
*/
/*
* Check if space is available in the ring. We use ring->head, which
* points to the next netmap slot to be published to netmap. It is
* possible that the applications moves ring->cur ahead of ring->tail
* (e.g., by setting ring->cur <== ring->tail), if it wants more slots
* than the ones currently available, and it wants to be notified when
* more arrive. See netmap(4) for more details and examples.
*/
static inline int
nm_ring_empty(struct netmap_ring *ring)
{
return (ring->head == ring->tail);
}
/*
* 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 at least a 'host' rings 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 */
const uint32_t ni_host_tx_rings; /* number of SW tx rings */
const uint32_t ni_host_rx_rings; /* number of SW rx rings */
uint32_t ni_spare1[3];
/*
* 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 rings (ni_host_tx_rings);
* - NIC rx rings (ni_rx_rings);
* - host rx ring (ni_host_rx_rings);
*
* The area is filled up by the kernel on NETMAP_REQ_REGISTER,
* and then only read by userspace code.
*/
const ssize_t ring_ofs[0];
};
/* Legacy interface to interact with a netmap control device.
* Included for backward compatibility. The user should not include this
* file directly. */
#include "netmap_legacy.h"
/*
* New API to control netmap control devices. New applications should only use
* nmreq_xyz structs with the NIOCCTRL ioctl() command.
*
* NIOCCTRL takes a nmreq_header struct, which contains the required
* API version, the name of a netmap port, a command type, and pointers
* to request body and options.
*
* nr_name (in)
* The name of the port (em0, valeXXX:YYY, eth0{pn1 etc.)
*
* nr_version (in/out)
* Must match NETMAP_API as used in the kernel, error otherwise.
* Always returns the desired value on output.
*
* nr_reqtype (in)
* One of the NETMAP_REQ_* command types below
*
* nr_body (in)
* Pointer to a command-specific struct, described by one
* of the struct nmreq_xyz below.
*
* nr_options (in)
* Command specific options, if any.
*
* A NETMAP_REQ_REGISTER command activates netmap mode on the netmap
* port (e.g. physical interface) specified by nmreq_header.nr_name.
* The request body (struct nmreq_register) has several arguments to
* specify how the port is to be registered.
*
* nr_tx_slots, nr_tx_slots, nr_tx_rings, nr_rx_rings,
* nr_host_tx_rings, nr_host_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_mode (in)
* Indicate what set of rings must be bound to the netmap
* device (e.g. all NIC rings, host rings only, NIC and
* host rings, ...). Values are in NR_REG_*.
*
* nr_ringid (in)
* If nr_mode == NR_REG_ONE_NIC (only a single couple of TX/RX
* rings), indicate which NIC TX and/or RX ring is to be bound
* (0..nr_*x_rings-1).
*
* nr_flags (in)
* Indicate special options for how to open the port.
*
* NR_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.
*
* NR_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.
*
* Other options are NR_MONITOR_TX, NR_MONITOR_RX, NR_ZCOPY_MON,
* NR_EXCLUSIVE, NR_RX_RINGS_ONLY, NR_TX_RINGS_ONLY and
* NR_ACCEPT_VNET_HDR.
*
* nr_mem_id (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_extra_bufs (in/out)
* Number of extra buffers to be allocated.
*
* The other NETMAP_REQ_* commands are described below.
*
*/
/* maximum size of a request, including all options */
#define NETMAP_REQ_MAXSIZE 4096
/* Header common to all request options. */
struct nmreq_option {
/* Pointer to the next option. */
uint64_t nro_next;
/* Option type. */
uint32_t nro_reqtype;
/* (out) status of the option:
* 0: recognized and processed
* !=0: errno value
*/
uint32_t nro_status;
/* Option size, used only for options that can have variable size
* (e.g. because they contain arrays). For fixed-size options this
* field should be set to zero. */
uint64_t nro_size;
};
/* Header common to all requests. Do not reorder these fields, as we need
* the second one (nr_reqtype) to know how much to copy from/to userspace. */
struct nmreq_header {
uint16_t nr_version; /* API version */
uint16_t nr_reqtype; /* nmreq type (NETMAP_REQ_*) */
uint32_t nr_reserved; /* must be zero */
#define NETMAP_REQ_IFNAMSIZ 64
char nr_name[NETMAP_REQ_IFNAMSIZ]; /* port name */
uint64_t nr_options; /* command-specific options */
uint64_t nr_body; /* ptr to nmreq_xyz struct */
};
enum {
/* Register a netmap port with the device. */
NETMAP_REQ_REGISTER = 1,
/* Get information from a netmap port. */
NETMAP_REQ_PORT_INFO_GET,
/* Attach a netmap port to a VALE switch. */
NETMAP_REQ_VALE_ATTACH,
/* Detach a netmap port from a VALE switch. */
NETMAP_REQ_VALE_DETACH,
/* List the ports attached to a VALE switch. */
NETMAP_REQ_VALE_LIST,
/* Set the port header length (was virtio-net header length). */
NETMAP_REQ_PORT_HDR_SET,
/* Get the port header length (was virtio-net header length). */
NETMAP_REQ_PORT_HDR_GET,
/* Create a new persistent VALE port. */
NETMAP_REQ_VALE_NEWIF,
/* Delete a persistent VALE port. */
NETMAP_REQ_VALE_DELIF,
/* Enable polling kernel thread(s) on an attached VALE port. */
NETMAP_REQ_VALE_POLLING_ENABLE,
/* Disable polling kernel thread(s) on an attached VALE port. */
NETMAP_REQ_VALE_POLLING_DISABLE,
/* Get info about the pools of a memory allocator. */
NETMAP_REQ_POOLS_INFO_GET,
/* Start an in-kernel loop that syncs the rings periodically or
* on notifications. The loop runs in the context of the ioctl
* syscall, and only stops on NETMAP_REQ_SYNC_KLOOP_STOP. */
NETMAP_REQ_SYNC_KLOOP_START,
/* Stops the thread executing the in-kernel loop. The thread
* returns from the ioctl syscall. */
NETMAP_REQ_SYNC_KLOOP_STOP,
/* Enable CSB mode on a registered netmap control device. */
NETMAP_REQ_CSB_ENABLE,
};
enum {
/* On NETMAP_REQ_REGISTER, ask netmap to use memory allocated
* from user-space allocated memory pools (e.g. hugepages).
*/
NETMAP_REQ_OPT_EXTMEM = 1,
/* ON NETMAP_REQ_SYNC_KLOOP_START, ask netmap to use eventfd-based
* notifications to synchronize the kernel loop with the application.
*/
NETMAP_REQ_OPT_SYNC_KLOOP_EVENTFDS,
/* On NETMAP_REQ_REGISTER, ask netmap to work in CSB mode, where
* head, cur and tail pointers are not exchanged through the
* struct netmap_ring header, but rather using an user-provided
* memory area (see struct nm_csb_atok and struct nm_csb_ktoa).
*/
NETMAP_REQ_OPT_CSB,
/* An extension to NETMAP_REQ_OPT_SYNC_KLOOP_EVENTFDS, which specifies
* if the TX and/or RX rings are synced in the context of the VM exit.
* This requires the 'ioeventfd' fields to be valid (cannot be < 0).
*/
NETMAP_REQ_OPT_SYNC_KLOOP_MODE,
/* On NETMAP_REQ_REGISTER, ask for (part of) the ptr field in the
* slots of the registered rings to be used as an offset field
* for the start of the packets inside the netmap buffer.
*/
NETMAP_REQ_OPT_OFFSETS,
/* This is a marker to count the number of available options.
* New options must be added above it. */
NETMAP_REQ_OPT_MAX,
};
/*
* nr_reqtype: NETMAP_REQ_REGISTER
* Bind (register) a netmap port to this control device.
*/
struct nmreq_register {
uint64_t nr_offset; /* nifp offset in the shared region */
uint64_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_host_tx_rings; /* number of host tx rings */
uint16_t nr_host_rx_rings; /* number of host rx rings */
uint16_t nr_mem_id; /* id of the memory allocator */
uint16_t nr_ringid; /* ring(s) we care about */
uint32_t nr_mode; /* specify NR_REG_* modes */
uint32_t nr_extra_bufs; /* number of requested extra buffers */
uint64_t nr_flags; /* additional flags (see below) */
/* monitors use nr_ringid and nr_mode 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
/* 0x1000 unused */
#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, NETMAP_REQ_REGISTER 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
/* The following two have the same meaning of NETMAP_NO_TX_POLL and
* NETMAP_DO_RX_POLL. */
#define NR_DO_RX_POLL 0x10000
#define NR_NO_TX_POLL 0x20000
};
/* Valid values for nmreq_register.nr_mode (see above). */
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, /* deprecated, use "x{y" port name syntax */
NR_REG_PIPE_SLAVE = 6, /* deprecated, use "x}y" port name syntax */
NR_REG_NULL = 7,
NR_REG_ONE_SW = 8,
};
/* A single ioctl number is shared by all the new API command.
* Demultiplexing is done using the hdr.nr_reqtype field.
* FreeBSD uses the size value embedded in the _IOWR to determine
* how much to copy in/out, so we define the ioctl() command
* specifying only nmreq_header, and copyin/copyout the rest. */
#define NIOCCTRL _IOWR('i', 151, struct nmreq_header)
/* The ioctl commands to sync TX/RX netmap rings.
* NIOCTXSYNC, NIOCRXSYNC synchronize tx or rx queues,
* whose identity is set in NETMAP_REQ_REGISTER through nr_ringid.
* These are non blocking and take no argument. */
#define NIOCTXSYNC _IO('i', 148) /* sync tx queues */
#define NIOCRXSYNC _IO('i', 149) /* sync rx queues */
/*
* nr_reqtype: NETMAP_REQ_PORT_INFO_GET
* Get information about a netmap port, including number of rings.
* slots per ring, id of the memory allocator, etc. The netmap
* control device used for this operation does not need to be bound
* to a netmap port.
*/
struct nmreq_port_info_get {
uint64_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_host_tx_rings; /* number of host tx rings */
uint16_t nr_host_rx_rings; /* number of host rx rings */
uint16_t nr_mem_id; /* memory allocator id (in/out) */
uint16_t pad[3];
};
#define NM_BDG_NAME "vale" /* prefix for bridge port name */
/*
* nr_reqtype: NETMAP_REQ_VALE_ATTACH
* Attach a netmap port to a VALE switch. Both the name of the netmap
* port and the VALE switch are specified through the nr_name argument.
* The attach operation could need to register a port, so at least
* the same arguments are available.
* port_index will contain the index where the port has been attached.
*/
struct nmreq_vale_attach {
struct nmreq_register reg;
uint32_t port_index;
uint32_t pad1;
};
/*
* nr_reqtype: NETMAP_REQ_VALE_DETACH
* Detach a netmap port from a VALE switch. Both the name of the netmap
* port and the VALE switch are specified through the nr_name argument.
* port_index will contain the index where the port was attached.
*/
struct nmreq_vale_detach {
uint32_t port_index;
uint32_t pad1;
};
/*
* nr_reqtype: NETMAP_REQ_VALE_LIST
* List the ports of a VALE switch.
*/
struct nmreq_vale_list {
/* Name of the VALE port (valeXXX:YYY) or empty. */
uint16_t nr_bridge_idx;
uint16_t pad1;
uint32_t nr_port_idx;
};
/*
* nr_reqtype: NETMAP_REQ_PORT_HDR_SET or NETMAP_REQ_PORT_HDR_GET
* Set or get the port header length of the port identified by hdr.nr_name.
* The control device does not need to be bound to a netmap port.
*/
struct nmreq_port_hdr {
uint32_t nr_hdr_len;
uint32_t pad1;
};
/*
* nr_reqtype: NETMAP_REQ_VALE_NEWIF
* Create a new persistent VALE port.
*/
struct nmreq_vale_newif {
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_mem_id; /* id of the memory allocator */
uint16_t pad1;
};
/*
* nr_reqtype: NETMAP_REQ_VALE_POLLING_ENABLE or NETMAP_REQ_VALE_POLLING_DISABLE
* Enable or disable polling kthreads on a VALE port.
*/
struct nmreq_vale_polling {
uint32_t nr_mode;
#define NETMAP_POLLING_MODE_SINGLE_CPU 1
#define NETMAP_POLLING_MODE_MULTI_CPU 2
uint32_t nr_first_cpu_id;
uint32_t nr_num_polling_cpus;
uint32_t pad1;
};
/*
* nr_reqtype: NETMAP_REQ_POOLS_INFO_GET
* Get info about the pools of the memory allocator of the netmap
* port specified by hdr.nr_name and nr_mem_id. The netmap control
* device used for this operation does not need to be bound to a netmap
* port.
*/
struct nmreq_pools_info {
uint64_t nr_memsize;
uint16_t nr_mem_id; /* in/out argument */
uint16_t pad1[3];
uint64_t nr_if_pool_offset;
uint32_t nr_if_pool_objtotal;
uint32_t nr_if_pool_objsize;
uint64_t nr_ring_pool_offset;
uint32_t nr_ring_pool_objtotal;
uint32_t nr_ring_pool_objsize;
uint64_t nr_buf_pool_offset;
uint32_t nr_buf_pool_objtotal;
uint32_t nr_buf_pool_objsize;
};
/*
* nr_reqtype: NETMAP_REQ_SYNC_KLOOP_START
* Start an in-kernel loop that syncs the rings periodically or on
* notifications. The loop runs in the context of the ioctl syscall,
* and only stops on NETMAP_REQ_SYNC_KLOOP_STOP.
* The registered netmap port must be open in CSB mode.
*/
struct nmreq_sync_kloop_start {
/* Sleeping is the default synchronization method for the kloop.
* The 'sleep_us' field specifies how many microseconds to sleep for
* when there is no work to do, before doing another kloop iteration.
*/
uint32_t sleep_us;
uint32_t pad1;
};
/* A CSB entry for the application --> kernel direction. */
struct nm_csb_atok {
uint32_t head; /* AW+ KR+ the head of the appl netmap_ring */
uint32_t cur; /* AW+ KR+ the cur of the appl netmap_ring */
uint32_t appl_need_kick; /* AW+ KR+ kern --> appl notification enable */
uint32_t sync_flags; /* AW+ KR+ the flags of the appl [tx|rx]sync() */
uint32_t pad[12]; /* pad to a 64 bytes cacheline */
};
/* A CSB entry for the application <-- kernel direction. */
struct nm_csb_ktoa {
uint32_t hwcur; /* AR+ KW+ the hwcur of the kern netmap_kring */
uint32_t hwtail; /* AR+ KW+ the hwtail of the kern netmap_kring */
uint32_t kern_need_kick; /* AR+ KW+ appl-->kern notification enable */
uint32_t pad[13];
};
#ifdef __linux__
#ifdef __KERNEL__
#define nm_stst_barrier smp_wmb
#define nm_ldld_barrier smp_rmb
#define nm_stld_barrier smp_mb
#else /* !__KERNEL__ */
static inline void nm_stst_barrier(void)
{
/* A memory barrier with release semantic has the combined
* effect of a store-store barrier and a load-store barrier,
* which is fine for us. */
__atomic_thread_fence(__ATOMIC_RELEASE);
}
static inline void nm_ldld_barrier(void)
{
/* A memory barrier with acquire semantic has the combined
* effect of a load-load barrier and a store-load barrier,
* which is fine for us. */
__atomic_thread_fence(__ATOMIC_ACQUIRE);
}
#endif /* !__KERNEL__ */
#elif defined(__FreeBSD__)
#ifdef _KERNEL
#define nm_stst_barrier atomic_thread_fence_rel
#define nm_ldld_barrier atomic_thread_fence_acq
#define nm_stld_barrier atomic_thread_fence_seq_cst
#else /* !_KERNEL */
#ifdef __cplusplus
#include <atomic>
using std::memory_order_release;
using std::memory_order_acquire;
#else /* __cplusplus */
#include <stdatomic.h>
#endif /* __cplusplus */
static inline void nm_stst_barrier(void)
{
atomic_thread_fence(memory_order_release);
}
static inline void nm_ldld_barrier(void)
{
atomic_thread_fence(memory_order_acquire);
}
#endif /* !_KERNEL */
#else /* !__linux__ && !__FreeBSD__ */
#error "OS not supported"
#endif /* !__linux__ && !__FreeBSD__ */
/* Application side of sync-kloop: Write ring pointers (cur, head) to the CSB.
* This routine is coupled with sync_kloop_kernel_read(). */
static inline void
nm_sync_kloop_appl_write(struct nm_csb_atok *atok, uint32_t cur,
uint32_t head)
{
/* Issue a first store-store barrier to make sure writes to the
* netmap ring do not overcome updates on atok->cur and atok->head. */
nm_stst_barrier();
/*
* We need to write cur and head to the CSB but we cannot do it atomically.
* There is no way we can prevent the host from reading the updated value
* of one of the two and the old value of the other. However, if we make
* sure that the host never reads a value of head more recent than the
* value of cur we are safe. We can allow the host to read a value of cur
* more recent than the value of head, since in the netmap ring cur can be
* ahead of head and cur cannot wrap around head because it must be behind
* tail. Inverting the order of writes below could instead result into the
* host to think head went ahead of cur, which would cause the sync
* prologue to fail.
*
* The following memory barrier scheme is used to make this happen:
*
* Guest Host
*
* STORE(cur) LOAD(head)
* wmb() <-----------> rmb()
* STORE(head) LOAD(cur)
*
*/
atok->cur = cur;
nm_stst_barrier();
atok->head = head;
}
/* Application side of sync-kloop: Read kring pointers (hwcur, hwtail) from
* the CSB. This routine is coupled with sync_kloop_kernel_write(). */
static inline void
nm_sync_kloop_appl_read(struct nm_csb_ktoa *ktoa, uint32_t *hwtail,
uint32_t *hwcur)
{
/*
* We place a memory barrier to make sure that the update of hwtail never
* overtakes the update of hwcur.
* (see explanation in sync_kloop_kernel_write).
*/
*hwtail = ktoa->hwtail;
nm_ldld_barrier();
*hwcur = ktoa->hwcur;
/* Make sure that loads from ktoa->hwtail and ktoa->hwcur are not delayed
* after the loads from the netmap ring. */
nm_ldld_barrier();
}
/*
* data for NETMAP_REQ_OPT_* options
*/
struct nmreq_opt_sync_kloop_eventfds {
struct nmreq_option nro_opt; /* common header */
/* An array of N entries for bidirectional notifications between
* the kernel loop and the application. The number of entries and
* their order must agree with the CSB arrays passed in the
* NETMAP_REQ_OPT_CSB option. Each entry contains a file descriptor
* backed by an eventfd.
*
* If any of the 'ioeventfd' entries is < 0, the event loop uses
* the sleeping synchronization strategy (according to sleep_us),
* and keeps kern_need_kick always disabled.
* Each 'irqfd' can be < 0, and in that case the corresponding queue
* is never notified.
*/
struct {
/* Notifier for the application --> kernel loop direction. */
int32_t ioeventfd;
/* Notifier for the kernel loop --> application direction. */
int32_t irqfd;
} eventfds[0];
};
struct nmreq_opt_sync_kloop_mode {
struct nmreq_option nro_opt; /* common header */
#define NM_OPT_SYNC_KLOOP_DIRECT_TX (1 << 0)
#define NM_OPT_SYNC_KLOOP_DIRECT_RX (1 << 1)
uint32_t mode;
};
struct nmreq_opt_extmem {
struct nmreq_option nro_opt; /* common header */
uint64_t nro_usrptr; /* (in) ptr to usr memory */
struct nmreq_pools_info nro_info; /* (in/out) */
};
struct nmreq_opt_csb {
struct nmreq_option nro_opt;
/* Array of CSB entries for application --> kernel communication
* (N entries). */
uint64_t csb_atok;
/* Array of CSB entries for kernel --> application communication
* (N entries). */
uint64_t csb_ktoa;
};
/* option NETMAP_REQ_OPT_OFFSETS */
struct nmreq_opt_offsets {
struct nmreq_option nro_opt;
/* the user must declare the maximum offset value that she is
* going to put into the offset slot-fields. Any larger value
* found at runtime will be cropped. On output the (possibly
* higher) effective max value is returned.
*/
uint64_t nro_max_offset;
/* optional initial offset value, to be set in all slots. */
uint64_t nro_initial_offset;
/* number of bits in the lower part of the 'ptr' field to be
* used as the offset field. On output the (possibly larger)
* effective number of bits is returned.
* 0 means: use the whole ptr field.
*/
uint32_t nro_offset_bits;
/* required alignment for the beginning of the packets
* (base of the buffer plus offset) in the TX slots.
*/
uint32_t nro_tx_align;
/* Reserved: set to zero. */
uint64_t nro_min_gap;
};
#endif /* _NET_NETMAP_H_ */
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