The Tcpdump Group git mirrors - libpcap/blob - pcap-netmap.c

   1 /*
   2  * Copyright (C) 2014 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
   6  * are met:
   7  *
   8  *   1. Redistributions of source code must retain the above copyright
   9  *      notice, this list of conditions and the following disclaimer.
  10  *   2. Redistributions in binary form must reproduce the above copyright
  11  *      notice, this list of conditions and the following disclaimer in the
  12  *      documentation and/or other materials provided with the distribution.
  13  *
  14  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS''AND
  15  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  16  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  17  * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  18  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  19  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  20  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  21  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  22  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  23  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  24  * SUCH DAMAGE.
  25  */
  26
  27 #ifdef HAVE_CONFIG_H
  28 #include <config.h>
  29 #endif
  30
  31 #include <poll.h>
  32 #include <errno.h>
  33 #include <netdb.h>
  34 #include <stdio.h>
  35 #include <stdlib.h>
  36 #include <string.h>
  37 #include <unistd.h>
  38
  39 #define NETMAP_WITH_LIBS
  40 #include <net/netmap_user.h>
  41
  42 #include "pcap-int.h"
  43 #include "pcap-netmap.h"
  44
  45 #ifndef __FreeBSD__
  46   /*
  47    * On FreeBSD we use IFF_PPROMISC which is in ifr_flagshigh.
  48    * Remap to IFF_PROMISC on other platforms.
  49    *
  50    * XXX - DragonFly BSD?
  51    */
  52   #define IFF_PPROMISC  IFF_PROMISC
  53 #endif /* __FreeBSD__ */
  54
  55 struct pcap_netmap {
  56         struct nm_desc *d;      /* pointer returned by nm_open() */
  57         pcap_handler cb;        /* callback and argument */
  58         u_char *cb_arg;
  59         int must_clear_promisc; /* flag */
  60         uint64_t rx_pkts;       /* # of pkts received before the filter */
  61 };
  62
  63
  64 static int
  65 pcap_netmap_stats(pcap_t *p, struct pcap_stat *ps)
  66 {
  67         struct pcap_netmap *pn = p->priv;
  68
  69         ps->ps_recv = (u_int)pn->rx_pkts;
  70         ps->ps_drop = 0;
  71         ps->ps_ifdrop = 0;
  72         return 0;
  73 }
  74
  75
  76 static void
  77 pcap_netmap_filter(u_char *arg, struct pcap_pkthdr *h, const u_char *buf)
  78 {
  79         pcap_t *p = (pcap_t *)arg;
  80         struct pcap_netmap *pn = p->priv;
  81         const struct bpf_insn *pc = p->fcode.bf_insns;
  82
  83         ++pn->rx_pkts;
  84         if (pc == NULL || pcap_filter(pc, buf, h->len, h->caplen))
  85                 pn->cb(pn->cb_arg, h, buf);
  86 }
  87
  88
  89 static int
  90 pcap_netmap_dispatch(pcap_t *p, int cnt, pcap_handler cb, u_char *user)
  91 {
  92         int ret;
  93         struct pcap_netmap *pn = p->priv;
  94         struct nm_desc *d = pn->d;
  95         struct pollfd pfd = { .fd = p->fd, .events = POLLIN, .revents = 0 };
  96
  97         pn->cb = cb;
  98         pn->cb_arg = user;
  99
 100         for (;;) {
 101                 if (p->break_loop) {
 102                         p->break_loop = 0;
 103                         return PCAP_ERROR_BREAK;
 104                 }
 105                 /* nm_dispatch won't run forever */
 106
 107                 ret = nm_dispatch((void *)d, cnt, (void *)pcap_netmap_filter, (void *)p);
 108                 if (ret != 0)
 109                         break;
 110                 errno = 0;
 111                 ret = poll(&pfd, 1, p->opt.timeout);
 112         }
 113         return ret;
 114 }
 115
 116
 117 /* XXX need to check the NIOCTXSYNC/poll */
 118 static int
 119 pcap_netmap_inject(pcap_t *p, const void *buf, int size)
 120 {
 121         struct pcap_netmap *pn = p->priv;
 122         struct nm_desc *d = pn->d;
 123
 124         return nm_inject(d, buf, size);
 125 }
 126
 127
 128 static int
 129 pcap_netmap_ioctl(pcap_t *p, u_long what, uint32_t *if_flags)
 130 {
 131         struct pcap_netmap *pn = p->priv;
 132         struct nm_desc *d = pn->d;
 133         struct ifreq ifr;
 134         int error, fd = d->fd;
 135
 136 #ifdef linux
 137         fd = socket(AF_INET, SOCK_DGRAM, 0);
 138         if (fd < 0) {
 139                 fprintf(stderr, "Error: cannot get device control socket.\n");
 140                 return -1;
 141         }
 142 #endif /* linux */
 143         bzero(&ifr, sizeof(ifr));
 144         strncpy(ifr.ifr_name, d->req.nr_name, sizeof(ifr.ifr_name));
 145         switch (what) {
 146         case SIOCSIFFLAGS:
 147                 /*
 148                  * The flags we pass in are 32-bit and unsigned.
 149                  *
 150                  * On most if not all UN*Xes, ifr_flags is 16-bit and
 151                  * signed, and the result of assigning a longer
 152                  * unsigned value to a shorter signed value is
 153                  * implementation-defined (even if, in practice, it'll
 154                  * do what's intended on all platforms we support
 155                  * result of assigning a 32-bit unsigned value).
 156                  * So we mask out the upper 16 bits.
 157                  */
 158                 ifr.ifr_flags = *if_flags & 0xffff;
 159 #ifdef __FreeBSD__
 160                 /*
 161                  * In FreeBSD, we need to set the high-order flags,
 162                  * as we're using IFF_PPROMISC, which is in those bits.
 163                  *
 164                  * XXX - DragonFly BSD?
 165                  */
 166                 ifr.ifr_flagshigh = *if_flags >> 16;
 167 #endif /* __FreeBSD__ */
 168                 break;
 169         }
 170         error = ioctl(fd, what, &ifr);
 171         if (!error) {
 172                 switch (what) {
 173                 case SIOCGIFFLAGS:
 174                         /*
 175                          * The flags we return are 32-bit.
 176                          *
 177                          * On most if not all UN*Xes, ifr_flags is
 178                          * 16-bit and signed, and will get sign-
 179                          * extended, so that the upper 16 bits of
 180                          * those flags will be forced on.  So we
 181                          * mask out the upper 16 bits of the
 182                          * sign-extended value.
 183                          */
 184                         *if_flags = ifr.ifr_flags & 0xffff;
 185 #ifdef __FreeBSD__
 186                         /*
 187                          * In FreeBSD, we need to return the
 188                          * high-order flags, as we're using
 189                          * IFF_PPROMISC, which is in those bits.
 190                          *
 191                          * XXX - DragonFly BSD?
 192                          */
 193                         *if_flags |= (ifr.ifr_flagshigh << 16);
 194 #endif /* __FreeBSD__ */
 195                 }
 196         }
 197 #ifdef linux
 198         close(fd);
 199 #endif /* linux */
 200         return error ? -1 : 0;
 201 }
 202
 203
 204 static void
 205 pcap_netmap_close(pcap_t *p)
 206 {
 207         struct pcap_netmap *pn = p->priv;
 208         struct nm_desc *d = pn->d;
 209         uint32_t if_flags = 0;
 210
 211         if (pn->must_clear_promisc) {
 212                 pcap_netmap_ioctl(p, SIOCGIFFLAGS, &if_flags); /* fetch flags */
 213                 if (if_flags & IFF_PPROMISC) {
 214                         if_flags &= ~IFF_PPROMISC;
 215                         pcap_netmap_ioctl(p, SIOCSIFFLAGS, &if_flags);
 216                 }
 217         }
 218         nm_close(d);
 219         pcap_cleanup_live_common(p);
 220 }
 221
 222
 223 static int
 224 pcap_netmap_activate(pcap_t *p)
 225 {
 226         struct pcap_netmap *pn = p->priv;
 227         struct nm_desc *d;
 228         uint32_t if_flags = 0;
 229
 230         d = nm_open(p->opt.device, NULL, 0, NULL);
 231         if (d == NULL) {
 232                 pcap_fmt_errmsg_for_errno(p->errbuf, PCAP_ERRBUF_SIZE,
 233                     errno, "netmap open: cannot access %s",
 234                     p->opt.device);
 235                 pcap_cleanup_live_common(p);
 236                 return (PCAP_ERROR);
 237         }
 238 #if 0
 239         fprintf(stderr, "%s device %s priv %p fd %d ports %d..%d\n",
 240             __FUNCTION__, p->opt.device, d, d->fd,
 241             d->first_rx_ring, d->last_rx_ring);
 242 #endif
 243         pn->d = d;
 244         p->fd = d->fd;
 245
 246         /*
 247          * Turn a negative snapshot value (invalid), a snapshot value of
 248          * 0 (unspecified), or a value bigger than the normal maximum
 249          * value, into the maximum allowed value.
 250          *
 251          * If some application really *needs* a bigger snapshot
 252          * length, we should just increase MAXIMUM_SNAPLEN.
 253          */
 254         if (p->snapshot <= 0 || p->snapshot > MAXIMUM_SNAPLEN)
 255                 p->snapshot = MAXIMUM_SNAPLEN;
 256
 257         if (p->opt.promisc && !(d->req.nr_ringid & NETMAP_SW_RING)) {
 258                 pcap_netmap_ioctl(p, SIOCGIFFLAGS, &if_flags); /* fetch flags */
 259                 if (!(if_flags & IFF_PPROMISC)) {
 260                         pn->must_clear_promisc = 1;
 261                         if_flags |= IFF_PPROMISC;
 262                         pcap_netmap_ioctl(p, SIOCSIFFLAGS, &if_flags);
 263                 }
 264         }
 265         p->linktype = DLT_EN10MB;
 266         p->selectable_fd = p->fd;
 267         p->read_op = pcap_netmap_dispatch;
 268         p->inject_op = pcap_netmap_inject;
 269         p->setfilter_op = pcap_install_bpf_program;
 270         p->setdirection_op = NULL;
 271         p->set_datalink_op = NULL;
 272         p->getnonblock_op = pcap_getnonblock_fd;
 273         p->setnonblock_op = pcap_setnonblock_fd;
 274         p->stats_op = pcap_netmap_stats;
 275         p->cleanup_op = pcap_netmap_close;
 276
 277         return (0);
 278 }
 279
 280
 281 pcap_t *
 282 pcap_netmap_create(const char *device, char *ebuf, int *is_ours)
 283 {
 284         pcap_t *p;
 285
 286         *is_ours = (!strncmp(device, "netmap:", 7) || !strncmp(device, "vale", 4));
 287         if (! *is_ours)
 288                 return NULL;
 289         p = PCAP_CREATE_COMMON(ebuf, struct pcap_netmap);
 290         if (p == NULL)
 291                 return (NULL);
 292         p->activate_op = pcap_netmap_activate;
 293         return (p);
 294 }
 295
 296 /*
 297  * The "device name" for netmap devices isn't a name for a device, it's
 298  * an expression that indicates how the device should be set up, so
 299  * there's no way to enumerate them.
 300  */
 301 int
 302 pcap_netmap_findalldevs(pcap_if_list_t *devlistp _U_, char *err_str _U_)
 303 {
 304         return 0;
 305 }