sys/net/netmap_user.h

   1 /*
   2  * Copyright (C) 2011 Matteo Landi, Luigi Rizzo. All rights reserved.
   3  * Copyright (C) 2013 Universita` di Pisa
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  *
   9  *   1. Redistributions of source code must retain the above copyright
  10  *      notice, this list of conditions and the following disclaimer.
  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 distribution.
  14  *
  15  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  16  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  17  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  18  * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  19  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  20  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  21  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  22  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  23  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  24  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  25  * SUCH DAMAGE.
  26  */
  27
  28 /*
  29  * $FreeBSD$
  30  *
  31  * This header contains the macros used to manipulate netmap structures
  32  * and packets in userspace. See netmap(4) for more information.
  33  *
  34  * The address of the struct netmap_if, say nifp, is computed from the
  35  * value returned from ioctl(.., NIOCREG, ...) and the mmap region:
  36  *      ioctl(fd, NIOCREG, &req);
  37  *      mem = mmap(0, ... );
  38  *      nifp = NETMAP_IF(mem, req.nr_nifp);
  39  *              (so simple, we could just do it manually)
  40  *
  41  * From there:
  42  *      struct netmap_ring *NETMAP_TXRING(nifp, index)
  43  *      struct netmap_ring *NETMAP_RXRING(nifp, index)
  44  *              we can access ring->nr_cur, ring->nr_avail, ring->nr_flags
  45  *
  46  *      ring->slot[i] gives us the i-th slot (we can access
  47  *              directly plen, flags, bufindex)
  48  *
  49  *      char *buf = NETMAP_BUF(ring, x) returns a pointer to
  50  *              the buffer numbered x
  51  *
  52  * Since rings are circular, we have macros to compute the next index
  53  *      i = NETMAP_RING_NEXT(ring, i);
  54  *
  55  * To ease porting apps from pcap to netmap we supply a few fuctions
  56  * that can be called to open, close and read from netmap in a way
  57  * similar to libpcap.
  58  *
  59  * In order to use these, include #define NETMAP_WITH_LIBS
  60  * in the source file that invokes these functions.
  61  */
  62
  63 #ifndef _NET_NETMAP_USER_H_
  64 #define _NET_NETMAP_USER_H_
  65
  66 #include <stdint.h>
  67 #include <net/if.h>             /* IFNAMSIZ */
  68 #include <net/netmap.h>
  69
  70 #define _NETMAP_OFFSET(type, ptr, offset) \
  71         ((type)(void *)((char *)(ptr) + (offset)))
  72
  73 #define NETMAP_IF(b, o) _NETMAP_OFFSET(struct netmap_if *, b, o)
  74
  75 #define NETMAP_TXRING(nifp, index) _NETMAP_OFFSET(struct netmap_ring *, \
  76         nifp, (nifp)->ring_ofs[index] )
  77
  78 #define NETMAP_RXRING(nifp, index) _NETMAP_OFFSET(struct netmap_ring *, \
  79         nifp, (nifp)->ring_ofs[index + (nifp)->ni_tx_rings + 1] )
  80
  81 #define NETMAP_BUF(ring, index)                         \
  82         ((char *)(ring) + (ring)->buf_ofs + ((index)*(ring)->nr_buf_size))
  83
  84 #define NETMAP_BUF_IDX(ring, buf)                       \
  85         ( ((char *)(buf) - ((char *)(ring) + (ring)->buf_ofs) ) / \
  86                 (ring)->nr_buf_size )
  87
  88 #define NETMAP_RING_NEXT(r, i)                          \
  89         ((i)+1 == (r)->num_slots ? 0 : (i) + 1 )
  90
  91 #define NETMAP_RING_FIRST_RESERVED(r)                   \
  92         ( (r)->cur < (r)->reserved ?                    \
  93           (r)->cur + (r)->num_slots - (r)->reserved :   \
  94           (r)->cur - (r)->reserved )
  95
  96 /*
  97  * Return 1 if the given tx ring is empty.
  98  */
  99 #define NETMAP_TX_RING_EMPTY(r) ((r)->avail >= (r)->num_slots - 1)
 100
 101 #ifdef NETMAP_WITH_LIBS
 102 /*
 103  * Support for simple I/O libraries.
 104  * Include other system headers required for compiling this.
 105  */
 106
 107 #ifndef HAVE_NETMAP_WITH_LIBS
 108 #define HAVE_NETMAP_WITH_LIBS
 109
 110 #include <sys/time.h>
 111 #include <sys/mman.h>
 112 #include <string.h>     /* memset */
 113 #include <sys/ioctl.h>
 114 #include <sys/errno.h>  /* EINVAL */
 115 #include <fcntl.h>      /* O_RDWR */
 116 #include <malloc.h>
 117
 118 struct nm_hdr_t {       /* same as pcap_pkthdr */
 119         struct timeval  ts;
 120         uint32_t        caplen;
 121         uint32_t        len;
 122 };
 123
 124 struct nm_desc_t {
 125         struct nm_desc_t *self;
 126         int fd;
 127         void *mem;
 128         int memsize;
 129         struct netmap_if *nifp;
 130         uint16_t first_ring, last_ring, cur_ring;
 131         struct nmreq req;
 132         struct nm_hdr_t hdr;
 133 };
 134
 135 /*
 136  * when the descriptor is open correctly, d->self == d
 137  */
 138 #define P2NMD(p)                ((struct nm_desc_t *)(p))
 139 #define IS_NETMAP_DESC(d)       (P2NMD(d)->self == P2NMD(d))
 140 #define NETMAP_FD(d)            (P2NMD(d)->fd)
 141
 142 /*
 143  * The callback, invoked on each received packet. Same as libpcap
 144  */
 145 typedef void (*nm_cb_t)(u_char *, const struct nm_hdr_t *, const u_char *d);
 146
 147 /*
 148  * The open routine accepts an ifname (netmap:foo or vale:foo) and
 149  * optionally a second (string) argument indicating the ring number
 150  * to open. If successful, t opens the fd and maps the memory.
 151  */
 152 static struct nm_desc_t *nm_open(const char *ifname,
 153          const char *ring_no, int flags, int ring_flags);
 154
 155 /*
 156  * nm_dispatch() is the same as pcap_dispatch()
 157  * nm_next() is the same as pcap_next()
 158  */
 159 static int nm_dispatch(struct nm_desc_t *, int, nm_cb_t, u_char *);
 160 static u_char *nm_next(struct nm_desc_t *, struct nm_hdr_t *);
 161
 162 /*
 163  * unmap memory, close file descriptor and free the descriptor.
 164  */
 165 static int nm_close(struct nm_desc_t *);
 166
 167
 168 /*
 169  * Try to open, return descriptor if successful, NULL otherwise.
 170  * An invalid netmap name will return errno = 0;
 171  */
 172 static struct nm_desc_t *
 173 nm_open(const char *ifname, const char *ring_name, int flags, int ring_flags)
 174 {
 175         struct nm_desc_t *d;
 176         u_int n;
 177
 178         if (strncmp(ifname, "netmap:", 7) && strncmp(ifname, "vale", 4)) {
 179                 errno = 0; /* name not recognised */
 180                 return NULL;
 181         }
 182         if (ifname[0] == 'n')
 183                 ifname += 7;
 184         d = (struct nm_desc_t *)calloc(1, sizeof(*d));
 185         if (d == NULL) {
 186                 errno = ENOMEM;
 187                 return NULL;
 188         }
 189         d->self = d;    /* set this early so nm_close() works */
 190         d->fd = open("/dev/netmap", O_RDWR);
 191         if (d->fd < 0)
 192                 goto fail;
 193
 194         if (flags & NETMAP_SW_RING) {
 195                 d->req.nr_ringid = NETMAP_SW_RING;
 196         } else {
 197                 u_int r;
 198                 if (flags & NETMAP_HW_RING) /* interpret ring as int */
 199                         r = (uintptr_t)ring_name;
 200                 else /* interpret ring as numeric string */
 201                         r = ring_name ? atoi(ring_name) : ~0;
 202                 r = (r < NETMAP_RING_MASK) ? (r | NETMAP_HW_RING) : 0;
 203                 d->req.nr_ringid = r; /* set the ring */
 204         }
 205         d->req.nr_ringid |= (flags & ~NETMAP_RING_MASK);
 206         d->req.nr_version = NETMAP_API;
 207         strncpy(d->req.nr_name, ifname, sizeof(d->req.nr_name));
 208         if (ioctl(d->fd, NIOCREGIF, &d->req))
 209                 goto fail;
 210
 211         d->memsize = d->req.nr_memsize;
 212         d->mem = mmap(0, d->memsize, PROT_WRITE | PROT_READ, MAP_SHARED,
 213                         d->fd, 0);
 214         if (d->mem == NULL)
 215                 goto fail;
 216         d->nifp = NETMAP_IF(d->mem, d->req.nr_offset);
 217         if (d->req.nr_ringid & NETMAP_SW_RING) {
 218                 d->first_ring = d->last_ring = d->req.nr_rx_rings;
 219         } else if (d->req.nr_ringid & NETMAP_HW_RING) {
 220                 d->first_ring = d->last_ring =
 221                         d->req.nr_ringid & NETMAP_RING_MASK;
 222         } else {
 223                 d->first_ring = 0;
 224                 d->last_ring = d->req.nr_rx_rings - 1;
 225         }
 226         d->cur_ring = d->first_ring;
 227         for (n = d->first_ring; n <= d->last_ring; n++) {
 228                 struct netmap_ring *ring = NETMAP_RXRING(d->nifp, n);
 229                 ring->flags |= ring_flags;
 230         }
 231         return d;
 232
 233 fail:
 234         nm_close(d);
 235         errno = EINVAL;
 236         return NULL;
 237 }
 238
 239
 240 static int
 241 nm_close(struct nm_desc_t *d)
 242 {
 243         if (d == NULL || d->self != d)
 244                 return EINVAL;
 245         if (d->mem)
 246                 munmap(d->mem, d->memsize);
 247         if (d->fd)
 248                 close(d->fd);
 249         bzero(d, sizeof(*d));
 250         free(d);
 251         return 0;
 252 }
 253
 254
 255 /*
 256  * Same prototype as pcap_dispatch(), only need to cast.
 257  */
 258 inline /* not really, but disable unused warnings */
 259 static int
 260 nm_dispatch(struct nm_desc_t *d, int cnt, nm_cb_t cb, u_char *arg)
 261 {
 262         int n = d->last_ring - d->first_ring + 1;
 263         int c, got = 0, ri = d->cur_ring;
 264
 265         if (cnt == 0)
 266                 cnt = -1;
 267         /* cnt == -1 means infinite, but rings have a finite amount
 268          * of buffers and the int is large enough that we never wrap,
 269          * so we can omit checking for -1
 270          */
 271         for (c=0; c < n && cnt != got; c++) {
 272                 /* compute current ring to use */
 273                 struct netmap_ring *ring;
 274
 275                 ri = d->cur_ring + c;
 276                 if (ri > d->last_ring)
 277                         ri = d->first_ring;
 278                 ring = NETMAP_RXRING(d->nifp, ri);
 279                 for ( ; ring->avail > 0 && cnt != got; got++) {
 280                         u_int i = ring->cur;
 281                         u_int idx = ring->slot[i].buf_idx;
 282                         u_char *buf = (u_char *)NETMAP_BUF(ring, idx);
 283                         // XXX should check valid buf
 284                         // prefetch(buf);
 285                         d->hdr.len = d->hdr.caplen = ring->slot[i].len;
 286                         d->hdr.ts = ring->ts;
 287                         cb(arg, &d->hdr, buf);
 288                         ring->cur = NETMAP_RING_NEXT(ring, i);
 289                         ring->avail--;
 290                 }
 291         }
 292         d->cur_ring = ri;
 293         return got;
 294 }
 295
 296 inline /* not really, but disable unused warnings */
 297 static u_char *
 298 nm_next(struct nm_desc_t *d, struct nm_hdr_t *hdr)
 299 {
 300         int ri = d->cur_ring;
 301
 302         do {
 303                 /* compute current ring to use */
 304                 struct netmap_ring *ring = NETMAP_RXRING(d->nifp, ri);
 305                 if (ring->avail > 0) {
 306                         u_int i = ring->cur;
 307                         u_int idx = ring->slot[i].buf_idx;
 308                         u_char *buf = (u_char *)NETMAP_BUF(ring, idx);
 309                         // XXX should check valid buf
 310                         // prefetch(buf);
 311                         hdr->ts = ring->ts;
 312                         hdr->len = hdr->caplen = ring->slot[i].len;
 313                         ring->cur = NETMAP_RING_NEXT(ring, i);
 314                         ring->avail--;
 315                         d->cur_ring = ri;
 316                         return buf;
 317                 }
 318                 ri++;
 319                 if (ri > d->last_ring)
 320                         ri = d->first_ring;
 321         } while (ri != d->cur_ring);
 322         return NULL; /* nothing found */
 323 }
 324
 325 #endif /* !HAVE_NETMAP_WITH_LIBS */
 326
 327 #endif /* NETMAP_WITH_LIBS */
 328
 329 #endif /* _NET_NETMAP_USER_H_ */