ceph/src/seastar/dpdk/examples/netmap_compat/netmap/netmap.h

   1 /*
   2  * Copyright (C) 2011 Matteo Landi, Luigi Rizzo. All rights reserved.
   3  *
   4  * Redistribution and use in source and binary forms, with or without
   5  * modification, are permitted provided that the following conditions are
   6  * met:
   7  *
   8  *   1. Redistributions of source code must retain the above copyright
   9  *      notice, this list of conditions and the following disclaimer.
  10  *
  11  *   2. Redistributions in binary form must reproduce the above copyright
  12  *      notice, this list of conditions and the following disclaimer in the
  13  *      documentation and/or other materials provided with the
  14  *      distribution.
  15  *
  16  *   3. Neither the name of the authors nor the names of their contributors
  17  *      may be used to endorse or promote products derived from this
  18  *      software without specific prior written permission.
  19  *
  20  * THIS SOFTWARE IS PROVIDED BY MATTEO LANDI AND CONTRIBUTORS "AS IS" AND
  21  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  22  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  23  * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL MATTEO LANDI OR CONTRIBUTORS
  24  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  25  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  26  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  27  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
  28  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  29  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
  30  * THE POSSIBILITY OF SUCH DAMAGE.
  31  */
  32
  33 /*
  34  * $FreeBSD: head/sys/net/netmap.h 231198 2012-02-08 11:43:29Z luigi $
  35  * $Id: netmap.h 10879 2012-04-12 22:48:59Z luigi $
  36  *
  37  * Definitions of constants and the structures used by the netmap
  38  * framework, for the part visible to both kernel and userspace.
  39  * Detailed info on netmap is available with "man netmap" or at
  40  *
  41  *      http://info.iet.unipi.it/~luigi/netmap/
  42  */
  43
  44 #ifndef _NET_NETMAP_H_
  45 #define _NET_NETMAP_H_
  46
  47 /*
  48  * --- Netmap data structures ---
  49  *
  50  * The data structures used by netmap are shown below. Those in
  51  * capital letters are in an mmapp()ed area shared with userspace,
  52  * while others are private to the kernel.
  53  * Shared structures do not contain pointers but only memory
  54  * offsets, so that addressing is portable between kernel and userspace.
  55
  56
  57  softc
  58 +----------------+
  59 | standard fields|
  60 | if_pspare[0] ----------+
  61 +----------------+       |
  62                          |
  63 +----------------+<------+
  64 |(netmap_adapter)|
  65 |                |                             netmap_kring
  66 | tx_rings *--------------------------------->+---------------+
  67 |                |       netmap_kring         | ring    *---------.
  68 | rx_rings *--------->+---------------+       | nr_hwcur      |   |
  69 +----------------+    | ring    *--------.    | nr_hwavail    |   V
  70                       | nr_hwcur      |  |    | selinfo       |   |
  71                       | nr_hwavail    |  |    +---------------+   .
  72                       | selinfo       |  |    |     ...       |   .
  73                       +---------------+  |    |(ntx+1 entries)|
  74                       |    ....       |  |    |               |
  75                       |(nrx+1 entries)|  |    +---------------+
  76                       |               |  |
  77    KERNEL             +---------------+  |
  78                                          |
  79   ====================================================================
  80                                          |
  81    USERSPACE                             |      NETMAP_RING
  82                                          +---->+-------------+
  83                                              / | cur         |
  84    NETMAP_IF  (nifp, one per file desc.)    /  | avail       |
  85     +---------------+                      /   | buf_ofs     |
  86     | ni_tx_rings   |                     /    +=============+
  87     | ni_rx_rings   |                    /     | buf_idx     | slot[0]
  88     |               |                   /      | len, flags  |
  89     |               |                  /       +-------------+
  90     +===============+                 /        | buf_idx     | slot[1]
  91     | txring_ofs[0] | (rel.to nifp)--'         | len, flags  |
  92     | txring_ofs[1] |                          +-------------+
  93   (num_rings+1 entries)                     (nr_num_slots entries)
  94     | txring_ofs[n] |                          | buf_idx     | slot[n-1]
  95     +---------------+                          | len, flags  |
  96     | rxring_ofs[0] |                          +-------------+
  97     | rxring_ofs[1] |
  98   (num_rings+1 entries)
  99     | txring_ofs[n] |
 100     +---------------+
 101
 102  * The private descriptor ('softc' or 'adapter') of each interface
 103  * is extended with a "struct netmap_adapter" containing netmap-related
 104  * info (see description in dev/netmap/netmap_kernel.h.
 105  * Among other things, tx_rings and rx_rings point to the arrays of
 106  * "struct netmap_kring" which in turn reache the various
 107  * "struct netmap_ring", shared with userspace.
 108
 109  * The NETMAP_RING is the userspace-visible replica of the NIC ring.
 110  * Each slot has the index of a buffer, its length and some flags.
 111  * In user space, the buffer address is computed as
 112  *      (char *)ring + buf_ofs + index*NETMAP_BUF_SIZE
 113  * In the kernel, buffers do not necessarily need to be contiguous,
 114  * and the virtual and physical addresses are derived through
 115  * a lookup table.
 116  * To associate a different buffer to a slot, applications must
 117  * write the new index in buf_idx, and set NS_BUF_CHANGED flag to
 118  * make sure that the kernel updates the hardware ring as needed.
 119  *
 120  * Normally the driver is not requested to report the result of
 121  * transmissions (this can dramatically speed up operation).
 122  * However the user may request to report completion by setting
 123  * NS_REPORT.
 124  */
 125 struct netmap_slot {
 126         uint32_t buf_idx; /* buffer index */
 127         uint16_t len;   /* packet length, to be copied to/from the hw ring */
 128         uint16_t flags; /* buf changed, etc. */
 129 #define NS_BUF_CHANGED  0x0001  /* must resync the map, buffer changed */
 130 #define NS_REPORT       0x0002  /* ask the hardware to report results
 131                                  * e.g. by generating an interrupt
 132                                  */
 133 };
 134
 135 /*
 136  * Netmap representation of a TX or RX ring (also known as "queue").
 137  * This is a queue implemented as a fixed-size circular array.
 138  * At the software level, two fields are important: avail and cur.
 139  *
 140  * In TX rings:
 141  *      avail   indicates the number of slots available for transmission.
 142  *              It is updated by the kernel after every netmap system call.
 143  *              It MUST BE decremented by the application when it appends a
 144  *              packet.
 145  *      cur     indicates the slot to use for the next packet
 146  *              to send (i.e. the "tail" of the queue).
 147  *              It MUST BE incremented by the application before
 148  *              netmap system calls to reflect the number of newly
 149  *              sent packets.
 150  *              It is checked by the kernel on netmap system calls
 151  *              (normally unmodified by the kernel unless invalid).
 152  *
 153  *   The kernel side of netmap uses two additional fields in its own
 154  *   private ring structure, netmap_kring:
 155  *      nr_hwcur is a copy of nr_cur on an NIOCTXSYNC.
 156  *      nr_hwavail is the number of slots known as available by the
 157  *              hardware. It is updated on an INTR (inc by the
 158  *              number of packets sent) and on a NIOCTXSYNC
 159  *              (decrease by nr_cur - nr_hwcur)
 160  *              A special case, nr_hwavail is -1 if the transmit
 161  *              side is idle (no pending transmits).
 162  *
 163  * In RX rings:
 164  *      avail   is the number of packets available (possibly 0).
 165  *              It MUST BE decremented by the application when it consumes
 166  *              a packet, and it is updated to nr_hwavail on a NIOCRXSYNC
 167  *      cur     indicates the first slot that contains a packet not
 168  *              processed yet (the "head" of the queue).
 169  *              It MUST BE incremented by the software when it consumes
 170  *              a packet.
 171  *      reserved        indicates the number of buffers before 'cur'
 172  *              that the application has still in use. Normally 0,
 173  *              it MUST BE incremented by the application when it
 174  *              does not return the buffer immediately, and decremented
 175  *              when the buffer is finally freed.
 176  *
 177  *   The kernel side of netmap uses two additional fields in the kring:
 178  *      nr_hwcur is a copy of nr_cur on an NIOCRXSYNC
 179  *      nr_hwavail is the number of packets available. It is updated
 180  *              on INTR (inc by the number of new packets arrived)
 181  *              and on NIOCRXSYNC (decreased by nr_cur - nr_hwcur).
 182  *
 183  * DATA OWNERSHIP/LOCKING:
 184  *      The netmap_ring is owned by the user program and it is only
 185  *      accessed or modified in the upper half of the kernel during
 186  *      a system call.
 187  *
 188  *      The netmap_kring is only modified by the upper half of the kernel.
 189  */
 190 struct netmap_ring {
 191         /*
 192          * nr_buf_base_ofs is meant to be used through macros.
 193          * It contains the offset of the buffer region from this
 194          * descriptor.
 195          */
 196         ssize_t buf_ofs;
 197         uint32_t        num_slots;      /* number of slots in the ring. */
 198         uint32_t        avail;          /* number of usable slots */
 199         uint32_t        cur;            /* 'current' r/w position */
 200         uint32_t        reserved;       /* not refilled before current */
 201
 202         uint16_t        nr_buf_size;
 203         uint16_t        flags;
 204 #define NR_TIMESTAMP    0x0002          /* set timestamp on *sync() */
 205
 206         struct timeval  ts;             /* time of last *sync() */
 207
 208         /* the slots follow. This struct has variable size */
 209         struct netmap_slot slot[0];     /* array of slots. */
 210 };
 211
 212
 213 /*
 214  * Netmap representation of an interface and its queue(s).
 215  * There is one netmap_if for each file descriptor on which we want
 216  * to select/poll.  We assume that on each interface has the same number
 217  * of receive and transmit queues.
 218  * select/poll operates on one or all pairs depending on the value of
 219  * nmr_queueid passed on the ioctl.
 220  */
 221 struct netmap_if {
 222         char            ni_name[IFNAMSIZ]; /* name of the interface. */
 223         u_int   ni_version;     /* API version, currently unused */
 224         u_int   ni_rx_rings;    /* number of rx rings */
 225         u_int   ni_tx_rings;    /* if zero, same as ni_rx_rings */
 226         /*
 227          * The following array contains the offset of each netmap ring
 228          * from this structure. The first ni_tx_queues+1 entries refer
 229          * to the tx rings, the next ni_rx_queues+1 refer to the rx rings
 230          * (the last entry in each block refers to the host stack rings).
 231          * The area is filled up by the kernel on NIOCREG,
 232          * and then only read by userspace code.
 233          */
 234         ssize_t ring_ofs[0];
 235 };
 236
 237 #ifndef NIOCREGIF
 238 /*
 239  * ioctl names and related fields
 240  *
 241  * NIOCGINFO takes a struct ifreq, the interface name is the input,
 242  *      the outputs are number of queues and number of descriptor
 243  *      for each queue (useful to set number of threads etc.).
 244  *
 245  * NIOCREGIF takes an interface name within a struct ifreq,
 246  *      and activates netmap mode on the interface (if possible).
 247  *
 248  * NIOCUNREGIF unregisters the interface associated to the fd.
 249  *
 250  * NIOCTXSYNC, NIOCRXSYNC synchronize tx or rx queues,
 251  *      whose identity is set in NIOCREGIF through nr_ringid
 252  */
 253
 254 /*
 255  * struct nmreq overlays a struct ifreq
 256  */
 257 struct nmreq {
 258         char            nr_name[IFNAMSIZ];
 259         uint32_t        nr_version;     /* API version */
 260 #define NETMAP_API      3               /* current version */
 261         uint32_t        nr_offset;      /* nifp offset in the shared region */
 262         uint32_t        nr_memsize;     /* size of the shared region */
 263         uint32_t        nr_tx_slots;    /* slots in tx rings */
 264         uint32_t        nr_rx_slots;    /* slots in rx rings */
 265         uint16_t        nr_tx_rings;    /* number of tx rings */
 266         uint16_t        nr_rx_rings;    /* number of rx rings */
 267         uint16_t        nr_ringid;      /* ring(s) we care about */
 268 #define NETMAP_HW_RING  0x4000          /* low bits indicate one hw ring */
 269 #define NETMAP_SW_RING  0x2000          /* process the sw ring */
 270 #define NETMAP_NO_TX_POLL       0x1000  /* no automatic txsync on poll */
 271 #define NETMAP_RING_MASK 0xfff          /* the ring number */
 272         uint16_t        spare1;
 273         uint32_t        spare2[4];
 274 };
 275
 276 /*
 277  * FreeBSD uses the size value embedded in the _IOWR to determine
 278  * how much to copy in/out. So we need it to match the actual
 279  * data structure we pass. We put some spares in the structure
 280  * to ease compatibility with other versions
 281  */
 282 #define NIOCGINFO       _IOWR('i', 145, struct nmreq) /* return IF info */
 283 #define NIOCREGIF       _IOWR('i', 146, struct nmreq) /* interface register */
 284 #define NIOCUNREGIF     _IO('i', 147) /* interface unregister */
 285 #define NIOCTXSYNC      _IO('i', 148) /* sync tx queues */
 286 #define NIOCRXSYNC      _IO('i', 149) /* sync rx queues */
 287 #endif /* !NIOCREGIF */
 288
 289 #endif /* _NET_NETMAP_H_ */