/* * 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. */ /* * $FreeBSD$ * $Id: netmap.h 9753 2011-11-28 15:10:43Z luigi $ * * This header contains the definitions of the constants and the * structures needed by the ``netmap'' module, both kernel and * userspace. */ #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 relative * offsets, so that addressing is portable between kernel and userspace. * * The 'softc' of each interface is extended with a struct netmap_adapter * containing information to support netmap operation. In addition to * the fixed fields, it has two pointers to reach the arrays of * 'struct netmap_kring' which in turn reaches the various * struct netmap_ring, shared with userspace. softc +----------------+ | standard fields| | if_pspare[0] ----------+ +----------------+ | | +----------------+<------+ |(netmap_adapter)| | | netmap_kring | tx_rings *--------------------------------->+-------------+ | | netmap_kring | ring *---------> ... | rx_rings *---------->+--------------+ | nr_hwcur | +----------------+ | ring *-------+ | nr_hwavail | | nr_hwcur | | | selinfo | | nr_hwavail | | +-------------+ | selinfo | | | ... | +--------------+ | (na_num_rings+1 entries) | .... | | | | (na_num_rings+1 entries) +-------------+ | | | +--------------+ | | NETMAP_RING +---->+-------------+ / | cur | NETMAP_IF (nifp, one per file desc.) / | avail | +---------------+ / | buf_ofs | | ni_num_queues | / +=============+ | | / | 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 NETMAP_RING is the shadow ring that mirrors the NIC rings. * 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*MAX_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. When userspace wants to use a different buffer * in a location, it must set the NS_BUF_CHANGED flag to make * sure that the kernel recomputes updates the hardware ring and * other fields (bus_dmamap, etc.) 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 decremented by the application when it appends a * packet, and set to nr_hwavail (see below) on a * NIOCTXSYNC to reflect the actual state of the queue * (keeping track of completed transmissions). * cur indicates the empty slot to use for the next packet * to send (i.e. the "tail" of the queue). * It is incremented by the application. * * 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 is decremented by the software when it consumes * a packet, and set to nr_hwavail on a NIOCRXSYNC * cur indicates the first slot that contains a packet * (the "head" of the queue). * It is incremented by the software when it consumes * a packet. * * 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 */ 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_num_queues; /* number of queue pairs (TX/RX). */ const u_int ni_rx_queues; /* if zero, use ni_num_queues */ /* * the following array contains the offset of the * each netmap ring from this structure. The first num_queues+1 * refer to the tx rings, the next n+1 refer to the rx rings. * The area is filled up by the kernel on NIOCREG, * and then only read by userspace code. * entries 0..ni_num_queues-1 indicate the hardware queues, * entry ni_num_queues is the queue from/to the stack. */ const ssize_t ring_ofs[0]; }; #ifndef IFCAP_NETMAP /* this should go in net/if.h */ #define IFCAP_NETMAP 0x100000 #endif #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 (unused) */ uint32_t nr_offset; /* nifp offset in the shared region */ uint32_t nr_memsize; /* size of the shared region */ uint32_t nr_numslots; /* descriptors per queue */ uint16_t nr_numrings; 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 /* we process the sw ring */ #define NETMAP_NO_TX_POLL 0x1000 /* no gratuitous txsync on poll */ #define NETMAP_RING_MASK 0xfff /* the ring number */ }; /* * default buf size is 2048, but it may make sense to have * it shorter for better cache usage. */ #define NETMAP_BUF_SIZE (2048) #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_ */