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

   1 /*
   2  * Copyright (c) 1990, 1991, 1992, 1993, 1994, 1995, 1996
   3  *      The Regents of the University of California.  All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that: (1) source code distributions
   7  * retain the above copyright notice and this paragraph in its entirety, (2)
   8  * distributions including binary code include the above copyright notice and
   9  * this paragraph in its entirety in the documentation or other materials
  10  * provided with the distribution, and (3) all advertising materials mentioning
  11  * features or use of this software display the following acknowledgement:
  12  * ``This product includes software developed by the University of California,
  13  * Lawrence Berkeley Laboratory and its contributors.'' Neither the name of
  14  * the University nor the names of its contributors may be used to endorse
  15  * or promote products derived from this software without specific prior
  16  * written permission.
  17  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED
  18  * WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
  19  * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
  20  *
  21  * Modifications made to accommodate the new SunOS4.0 NIT facility by
  22  * Micky Liu, micky@cunixc.cc.columbia.edu, Columbia University in May, 1989.
  23  * This module now handles the STREAMS based NIT.
  24  */
  25
  26 #ifdef HAVE_CONFIG_H
  27 #include <config.h>
  28 #endif
  29
  30 #include <sys/types.h>
  31 #include <sys/time.h>
  32 #include <sys/timeb.h>
  33 #include <sys/dir.h>
  34 #include <sys/fcntlcom.h>
  35 #include <sys/file.h>
  36 #include <sys/ioctl.h>
  37 #include <sys/socket.h>
  38 #include <sys/stropts.h>
  39
  40 #include <net/if.h>
  41 #include <net/nit.h>
  42 #include <net/nit_if.h>
  43 #include <net/nit_pf.h>
  44 #include <net/nit_buf.h>
  45
  46 #include <netinet/in.h>
  47 #include <netinet/in_systm.h>
  48 #include <netinet/ip.h>
  49 #include <netinet/if_ether.h>
  50 #include <netinet/ip_var.h>
  51 #include <netinet/udp.h>
  52 #include <netinet/udp_var.h>
  53 #include <netinet/tcp.h>
  54 #include <netinet/tcpip.h>
  55
  56 #include <errno.h>
  57 #include <stdio.h>
  58 #include <string.h>
  59 #include <unistd.h>
  60
  61 #include "pcap-int.h"
  62
  63 #ifdef HAVE_OS_PROTO_H
  64 #include "os-proto.h"
  65 #endif
  66
  67 /*
  68  * The chunk size for NIT.  This is the amount of buffering
  69  * done for read calls.
  70  */
  71 #define CHUNKSIZE (2*1024)
  72
  73 /*
  74  * The total buffer space used by NIT.
  75  */
  76 #define BUFSPACE (4*CHUNKSIZE)
  77
  78 /* Forwards */
  79 static int nit_setflags(int, int, int, char *);
  80
  81 /*
  82  * Private data for capturing on STREAMS NIT devices.
  83  */
  84 struct pcap_snit {
  85         struct pcap_stat stat;
  86 };
  87
  88 static int
  89 pcap_stats_snit(pcap_t *p, struct pcap_stat *ps)
  90 {
  91         struct pcap_snit *psn = p->priv;
  92
  93         /*
  94          * "ps_recv" counts packets handed to the filter, not packets
  95          * that passed the filter.  As filtering is done in userland,
  96          * this does not include packets dropped because we ran out
  97          * of buffer space.
  98          *
  99          * "ps_drop" counts packets dropped inside the "/dev/nit"
 100          * device because of flow control requirements or resource
 101          * exhaustion; it doesn't count packets dropped by the
 102          * interface driver, or packets dropped upstream.  As filtering
 103          * is done in userland, it counts packets regardless of whether
 104          * they would've passed the filter.
 105          *
 106          * These statistics don't include packets not yet read from the
 107          * kernel by libpcap or packets not yet read from libpcap by the
 108          * application.
 109          */
 110         *ps = psn->stat;
 111         return (0);
 112 }
 113
 114 static int
 115 pcap_read_snit(pcap_t *p, int cnt, pcap_handler callback, u_char *user)
 116 {
 117         struct pcap_snit *psn = p->priv;
 118         register int cc, n;
 119         register u_char *bp, *cp, *ep;
 120         register struct nit_bufhdr *hdrp;
 121         register struct nit_iftime *ntp;
 122         register struct nit_iflen *nlp;
 123         register struct nit_ifdrops *ndp;
 124         register int caplen;
 125
 126         cc = p->cc;
 127         if (cc == 0) {
 128                 cc = read(p->fd, (char *)p->buffer, p->bufsize);
 129                 if (cc < 0) {
 130                         if (errno == EWOULDBLOCK)
 131                                 return (0);
 132                         pcap_fmt_errmsg_for_errno(p->errbuf, sizeof(p->errbuf),
 133                             errno, "pcap_read");
 134                         return (-1);
 135                 }
 136                 bp = p->buffer;
 137         } else
 138                 bp = p->bp;
 139
 140         /*
 141          * loop through each snapshot in the chunk
 142          *
 143          * This assumes that a single buffer of packets will have
 144          * <= INT_MAX packets, so the packet count doesn't overflow.
 145          */
 146         n = 0;
 147         ep = bp + cc;
 148         while (bp < ep) {
 149                 /*
 150                  * Has "pcap_breakloop()" been called?
 151                  * If so, return immediately - if we haven't read any
 152                  * packets, clear the flag and return -2 to indicate
 153                  * that we were told to break out of the loop, otherwise
 154                  * leave the flag set, so that the *next* call will break
 155                  * out of the loop without having read any packets, and
 156                  * return the number of packets we've processed so far.
 157                  */
 158                 if (p->break_loop) {
 159                         if (n == 0) {
 160                                 p->break_loop = 0;
 161                                 return (-2);
 162                         } else {
 163                                 p->bp = bp;
 164                                 p->cc = ep - bp;
 165                                 return (n);
 166                         }
 167                 }
 168
 169                 ++psn->stat.ps_recv;
 170                 cp = bp;
 171
 172                 /* get past NIT buffer  */
 173                 hdrp = (struct nit_bufhdr *)cp;
 174                 cp += sizeof(*hdrp);
 175
 176                 /* get past NIT timer   */
 177                 ntp = (struct nit_iftime *)cp;
 178                 cp += sizeof(*ntp);
 179
 180                 ndp = (struct nit_ifdrops *)cp;
 181                 psn->stat.ps_drop = ndp->nh_drops;
 182                 cp += sizeof *ndp;
 183
 184                 /* get past packet len  */
 185                 nlp = (struct nit_iflen *)cp;
 186                 cp += sizeof(*nlp);
 187
 188                 /* next snapshot        */
 189                 bp += hdrp->nhb_totlen;
 190
 191                 caplen = nlp->nh_pktlen;
 192                 if (caplen > p->snapshot)
 193                         caplen = p->snapshot;
 194
 195                 if (pcap_filter(p->fcode.bf_insns, cp, nlp->nh_pktlen, caplen)) {
 196                         struct pcap_pkthdr h;
 197                         h.ts = ntp->nh_timestamp;
 198                         h.len = nlp->nh_pktlen;
 199                         h.caplen = caplen;
 200                         (*callback)(user, &h, cp);
 201                         if (++n >= cnt && !PACKET_COUNT_IS_UNLIMITED(cnt)) {
 202                                 p->cc = ep - bp;
 203                                 p->bp = bp;
 204                                 return (n);
 205                         }
 206                 }
 207         }
 208         p->cc = 0;
 209         return (n);
 210 }
 211
 212 static int
 213 pcap_inject_snit(pcap_t *p, const void *buf, int size)
 214 {
 215         struct strbuf ctl, data;
 216
 217         /*
 218          * XXX - can we just do
 219          *
 220         ret = write(pd->f, buf, size);
 221          */
 222         ctl.len = sizeof(*sa);  /* XXX - what was this? */
 223         ctl.buf = (char *)sa;
 224         data.buf = buf;
 225         data.len = size;
 226         ret = putmsg(p->fd, &ctl, &data);
 227         if (ret == -1) {
 228                 pcap_fmt_errmsg_for_errno(p->errbuf, PCAP_ERRBUF_SIZE,
 229                     errno, "send");
 230                 return (-1);
 231         }
 232         return (ret);
 233 }
 234
 235 static int
 236 nit_setflags(pcap_t *p)
 237 {
 238         bpf_u_int32 flags;
 239         struct strioctl si;
 240         u_int zero = 0;
 241         struct timeval timeout;
 242
 243         if (p->opt.immediate) {
 244                 /*
 245                  * Set the chunk size to zero, so that chunks get sent
 246                  * up immediately.
 247                  */
 248                 si.ic_cmd = NIOCSCHUNK;
 249                 si.ic_len = sizeof(zero);
 250                 si.ic_dp = (char *)&zero;
 251                 if (ioctl(p->fd, I_STR, (char *)&si) < 0) {
 252                         pcap_fmt_errmsg_for_errno(p->errbuf, PCAP_ERRBUF_SIZE,
 253                             errno, "NIOCSCHUNK");
 254                         return (-1);
 255                 }
 256         }
 257         si.ic_timout = INFTIM;
 258         if (p->opt.timeout != 0) {
 259                 timeout.tv_sec = p->opt.timeout / 1000;
 260                 timeout.tv_usec = (p->opt.timeout * 1000) % 1000000;
 261                 si.ic_cmd = NIOCSTIME;
 262                 si.ic_len = sizeof(timeout);
 263                 si.ic_dp = (char *)&timeout;
 264                 if (ioctl(p->fd, I_STR, (char *)&si) < 0) {
 265                         pcap_fmt_errmsg_for_errno(p->errbuf, PCAP_ERRBUF_SIZE,
 266                             errno, "NIOCSTIME");
 267                         return (-1);
 268                 }
 269         }
 270         flags = NI_TIMESTAMP | NI_LEN | NI_DROPS;
 271         if (p->opt.promisc)
 272                 flags |= NI_PROMISC;
 273         si.ic_cmd = NIOCSFLAGS;
 274         si.ic_len = sizeof(flags);
 275         si.ic_dp = (char *)&flags;
 276         if (ioctl(p->fd, I_STR, (char *)&si) < 0) {
 277                 pcap_fmt_errmsg_for_errno(p->errbuf, PCAP_ERRBUF_SIZE,
 278                     errno, "NIOCSFLAGS");
 279                 return (-1);
 280         }
 281         return (0);
 282 }
 283
 284 static int
 285 pcap_activate_snit(pcap_t *p)
 286 {
 287         struct strioctl si;             /* struct for ioctl() */
 288         struct ifreq ifr;               /* interface request struct */
 289         int chunksize = CHUNKSIZE;
 290         int fd;
 291         static const char dev[] = "/dev/nit";
 292         int err;
 293
 294         if (p->opt.rfmon) {
 295                 /*
 296                  * No monitor mode on SunOS 4.x (no Wi-Fi devices on
 297                  * hardware supported by SunOS 4.x).
 298                  */
 299                 return (PCAP_ERROR_RFMON_NOTSUP);
 300         }
 301
 302         /*
 303          * Turn a negative snapshot value (invalid), a snapshot value of
 304          * 0 (unspecified), or a value bigger than the normal maximum
 305          * value, into the maximum allowed value.
 306          *
 307          * If some application really *needs* a bigger snapshot
 308          * length, we should just increase MAXIMUM_SNAPLEN.
 309          */
 310         if (p->snapshot <= 0 || p->snapshot > MAXIMUM_SNAPLEN)
 311                 p->snapshot = MAXIMUM_SNAPLEN;
 312
 313         if (p->snapshot < 96)
 314                 /*
 315                  * NIT requires a snapshot length of at least 96.
 316                  */
 317                 p->snapshot = 96;
 318
 319         /*
 320          * Initially try a read/write open (to allow the inject
 321          * method to work).  If that fails due to permission
 322          * issues, fall back to read-only.  This allows a
 323          * non-root user to be granted specific access to pcap
 324          * capabilities via file permissions.
 325          *
 326          * XXX - we should have an API that has a flag that
 327          * controls whether to open read-only or read-write,
 328          * so that denial of permission to send (or inability
 329          * to send, if sending packets isn't supported on
 330          * the device in question) can be indicated at open
 331          * time.
 332          */
 333         p->fd = fd = open(dev, O_RDWR);
 334         if (fd < 0 && errno == EACCES)
 335                 p->fd = fd = open(dev, O_RDONLY);
 336         if (fd < 0) {
 337                 if (errno == EACCES) {
 338                         err = PCAP_ERROR_PERM_DENIED;
 339                         snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
 340                             "Attempt to open %s failed with EACCES - root privileges may be required",
 341                             dev);
 342                 } else {
 343                         err = PCAP_ERROR;
 344                         pcap_fmt_errmsg_for_errno(p->errbuf, PCAP_ERRBUF_SIZE,
 345                             errno, "%s", dev);
 346                 }
 347                 goto bad;
 348         }
 349
 350         /* arrange to get discrete messages from the STREAM and use NIT_BUF */
 351         if (ioctl(fd, I_SRDOPT, (char *)RMSGD) < 0) {
 352                 pcap_fmt_errmsg_for_errno(p->errbuf, PCAP_ERRBUF_SIZE,
 353                     errno, "I_SRDOPT");
 354                 err = PCAP_ERROR;
 355                 goto bad;
 356         }
 357         if (ioctl(fd, I_PUSH, "nbuf") < 0) {
 358                 pcap_fmt_errmsg_for_errno(p->errbuf, PCAP_ERRBUF_SIZE,
 359                     errno, "push nbuf");
 360                 err = PCAP_ERROR;
 361                 goto bad;
 362         }
 363         /* set the chunksize */
 364         si.ic_cmd = NIOCSCHUNK;
 365         si.ic_timout = INFTIM;
 366         si.ic_len = sizeof(chunksize);
 367         si.ic_dp = (char *)&chunksize;
 368         if (ioctl(fd, I_STR, (char *)&si) < 0) {
 369                 pcap_fmt_errmsg_for_errno(p->errbuf, PCAP_ERRBUF_SIZE,
 370                     errno, "NIOCSCHUNK");
 371                 err = PCAP_ERROR;
 372                 goto bad;
 373         }
 374
 375         /* request the interface */
 376         strncpy(ifr.ifr_name, p->opt.device, sizeof(ifr.ifr_name));
 377         ifr.ifr_name[sizeof(ifr.ifr_name) - 1] = '\0';
 378         si.ic_cmd = NIOCBIND;
 379         si.ic_len = sizeof(ifr);
 380         si.ic_dp = (char *)&ifr;
 381         if (ioctl(fd, I_STR, (char *)&si) < 0) {
 382                 /*
 383                  * XXX - is there an error that means "no such device"?
 384                  * Is there one that means "that device doesn't support
 385                  * STREAMS NIT"?
 386                  */
 387                 pcap_fmt_errmsg_for_errno(p->errbuf, PCAP_ERRBUF_SIZE,
 388                     errno, "NIOCBIND: %s", ifr.ifr_name);
 389                 err = PCAP_ERROR;
 390                 goto bad;
 391         }
 392
 393         /* set the snapshot length */
 394         si.ic_cmd = NIOCSSNAP;
 395         si.ic_len = sizeof(p->snapshot);
 396         si.ic_dp = (char *)&p->snapshot;
 397         if (ioctl(fd, I_STR, (char *)&si) < 0) {
 398                 pcap_fmt_errmsg_for_errno(p->errbuf, PCAP_ERRBUF_SIZE,
 399                     errno, "NIOCSSNAP");
 400                 err = PCAP_ERROR;
 401                 goto bad;
 402         }
 403         if (nit_setflags(p) < 0) {
 404                 err = PCAP_ERROR;
 405                 goto bad;
 406         }
 407
 408         (void)ioctl(fd, I_FLUSH, (char *)FLUSHR);
 409         /*
 410          * NIT supports only ethernets.
 411          */
 412         p->linktype = DLT_EN10MB;
 413
 414         p->bufsize = BUFSPACE;
 415         p->buffer = malloc(p->bufsize);
 416         if (p->buffer == NULL) {
 417                 pcap_fmt_errmsg_for_errno(p->errbuf, PCAP_ERRBUF_SIZE,
 418                     errno, "malloc");
 419                 err = PCAP_ERROR;
 420                 goto bad;
 421         }
 422
 423         /*
 424          * "p->fd" is an FD for a STREAMS device, so "select()" and
 425          * "poll()" should work on it.
 426          */
 427         p->selectable_fd = p->fd;
 428
 429         /*
 430          * This is (presumably) a real Ethernet capture; give it a
 431          * link-layer-type list with DLT_EN10MB and DLT_DOCSIS, so
 432          * that an application can let you choose it, in case you're
 433          * capturing DOCSIS traffic that a Cisco Cable Modem
 434          * Termination System is putting out onto an Ethernet (it
 435          * doesn't put an Ethernet header onto the wire, it puts raw
 436          * DOCSIS frames out on the wire inside the low-level
 437          * Ethernet framing).
 438          */
 439         p->dlt_list = (u_int *) malloc(sizeof(u_int) * 2);
 440         /*
 441          * If that fails, just leave the list empty.
 442          */
 443         if (p->dlt_list != NULL) {
 444                 p->dlt_list[0] = DLT_EN10MB;
 445                 p->dlt_list[1] = DLT_DOCSIS;
 446                 p->dlt_count = 2;
 447         }
 448
 449         p->read_op = pcap_read_snit;
 450         p->inject_op = pcap_inject_snit;
 451         p->setfilter_op = pcap_install_bpf_program;     /* no kernel filtering */
 452         p->setdirection_op = NULL;      /* Not implemented. */
 453         p->set_datalink_op = NULL;      /* can't change data link type */
 454         p->getnonblock_op = pcap_getnonblock_fd;
 455         p->setnonblock_op = pcap_setnonblock_fd;
 456         p->stats_op = pcap_stats_snit;
 457
 458         return (0);
 459  bad:
 460         pcap_cleanup_live_common(p);
 461         return (err);
 462 }
 463
 464 pcap_t *
 465 pcap_create_interface(const char *device _U_, char *ebuf)
 466 {
 467         pcap_t *p;
 468
 469         p = PCAP_CREATE_COMMON(ebuf, struct pcap_snit);
 470         if (p == NULL)
 471                 return (NULL);
 472
 473         p->activate_op = pcap_activate_snit;
 474         return (p);
 475 }
 476
 477 /*
 478  * XXX - there's probably a NIOCBIND error that means "that device
 479  * doesn't support NIT"; if so, we should try an NIOCBIND and use that.
 480  */
 481 static int
 482 can_be_bound(const char *name _U_)
 483 {
 484         return (1);
 485 }
 486
 487 static int
 488 get_if_flags(const char *name _U_, bpf_u_int32 *flags _U_, char *errbuf _U_)
 489 {
 490         /*
 491          * Nothing we can do.
 492          * XXX - is there a way to find out whether an adapter has
 493          * something plugged into it?
 494          */
 495         return (0);
 496 }
 497
 498 int
 499 pcap_platform_finddevs(pcap_if_list_t *devlistp, char *errbuf)
 500 {
 501         return (pcap_findalldevs_interfaces(devlistp, errbuf, can_be_bound,
 502             get_if_flags));
 503 }
 504
 505 /*
 506  * Libpcap version string.
 507  */
 508 const char *
 509 pcap_lib_version(void)
 510 {
 511         return (PCAP_VERSION_STRING);
 512 }