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freebsd-nq/sys/net/netmap.h

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/*
* 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.
*/
/*
* $FreeBSD$
*
* 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)
*/
#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.
*
* 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_LOOKUP_REG 3 /* register lookup function */
#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 */
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
/*
* 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 */
#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);
}
#endif /* _NET_NETMAP_H_ */
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