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 = (u_char *)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                 else
 340                         err = PCAP_ERROR;
 341                 pcap_fmt_errmsg_for_errno(p->errbuf, PCAP_ERRBUF_SIZE,
 342                     errno, "%s", dev);
 343                 goto bad;
 344         }
 345
 346         /* arrange to get discrete messages from the STREAM and use NIT_BUF */
 347         if (ioctl(fd, I_SRDOPT, (char *)RMSGD) < 0) {
 348                 pcap_fmt_errmsg_for_errno(p->errbuf, PCAP_ERRBUF_SIZE,
 349                     errno, "I_SRDOPT");
 350                 err = PCAP_ERROR;
 351                 goto bad;
 352         }
 353         if (ioctl(fd, I_PUSH, "nbuf") < 0) {
 354                 pcap_fmt_errmsg_for_errno(p->errbuf, PCAP_ERRBUF_SIZE,
 355                     errno, "push nbuf");
 356                 err = PCAP_ERROR;
 357                 goto bad;
 358         }
 359         /* set the chunksize */
 360         si.ic_cmd = NIOCSCHUNK;
 361         si.ic_timout = INFTIM;
 362         si.ic_len = sizeof(chunksize);
 363         si.ic_dp = (char *)&chunksize;
 364         if (ioctl(fd, I_STR, (char *)&si) < 0) {
 365                 pcap_fmt_errmsg_for_errno(p->errbuf, PCAP_ERRBUF_SIZE,
 366                     errno, "NIOCSCHUNK");
 367                 err = PCAP_ERROR;
 368                 goto bad;
 369         }
 370
 371         /* request the interface */
 372         strncpy(ifr.ifr_name, p->opt.device, sizeof(ifr.ifr_name));
 373         ifr.ifr_name[sizeof(ifr.ifr_name) - 1] = '\0';
 374         si.ic_cmd = NIOCBIND;
 375         si.ic_len = sizeof(ifr);
 376         si.ic_dp = (char *)&ifr;
 377         if (ioctl(fd, I_STR, (char *)&si) < 0) {
 378                 /*
 379                  * XXX - is there an error that means "no such device"?
 380                  * Is there one that means "that device doesn't support
 381                  * STREAMS NIT"?
 382                  */
 383                 pcap_fmt_errmsg_for_errno(p->errbuf, PCAP_ERRBUF_SIZE,
 384                     errno, "NIOCBIND: %s", ifr.ifr_name);
 385                 err = PCAP_ERROR;
 386                 goto bad;
 387         }
 388
 389         /* set the snapshot length */
 390         si.ic_cmd = NIOCSSNAP;
 391         si.ic_len = sizeof(p->snapshot);
 392         si.ic_dp = (char *)&p->snapshot;
 393         if (ioctl(fd, I_STR, (char *)&si) < 0) {
 394                 pcap_fmt_errmsg_for_errno(p->errbuf, PCAP_ERRBUF_SIZE,
 395                     errno, "NIOCSSNAP");
 396                 err = PCAP_ERROR;
 397                 goto bad;
 398         }
 399         if (nit_setflags(p) < 0) {
 400                 err = PCAP_ERROR;
 401                 goto bad;
 402         }
 403
 404         (void)ioctl(fd, I_FLUSH, (char *)FLUSHR);
 405         /*
 406          * NIT supports only ethernets.
 407          */
 408         p->linktype = DLT_EN10MB;
 409
 410         p->bufsize = BUFSPACE;
 411         p->buffer = malloc(p->bufsize);
 412         if (p->buffer == NULL) {
 413                 pcap_fmt_errmsg_for_errno(p->errbuf, PCAP_ERRBUF_SIZE,
 414                     errno, "malloc");
 415                 err = PCAP_ERROR;
 416                 goto bad;
 417         }
 418
 419         /*
 420          * "p->fd" is an FD for a STREAMS device, so "select()" and
 421          * "poll()" should work on it.
 422          */
 423         p->selectable_fd = p->fd;
 424
 425         /*
 426          * This is (presumably) a real Ethernet capture; give it a
 427          * link-layer-type list with DLT_EN10MB and DLT_DOCSIS, so
 428          * that an application can let you choose it, in case you're
 429          * capturing DOCSIS traffic that a Cisco Cable Modem
 430          * Termination System is putting out onto an Ethernet (it
 431          * doesn't put an Ethernet header onto the wire, it puts raw
 432          * DOCSIS frames out on the wire inside the low-level
 433          * Ethernet framing).
 434          */
 435         p->dlt_list = (u_int *) malloc(sizeof(u_int) * 2);
 436         /*
 437          * If that fails, just leave the list empty.
 438          */
 439         if (p->dlt_list != NULL) {
 440                 p->dlt_list[0] = DLT_EN10MB;
 441                 p->dlt_list[1] = DLT_DOCSIS;
 442                 p->dlt_count = 2;
 443         }
 444
 445         p->read_op = pcap_read_snit;
 446         p->inject_op = pcap_inject_snit;
 447         p->setfilter_op = install_bpf_program;  /* no kernel filtering */
 448         p->setdirection_op = NULL;      /* Not implemented. */
 449         p->set_datalink_op = NULL;      /* can't change data link type */
 450         p->getnonblock_op = pcap_getnonblock_fd;
 451         p->setnonblock_op = pcap_setnonblock_fd;
 452         p->stats_op = pcap_stats_snit;
 453
 454         return (0);
 455  bad:
 456         pcap_cleanup_live_common(p);
 457         return (err);
 458 }
 459
 460 pcap_t *
 461 pcap_create_interface(const char *device _U_, char *ebuf)
 462 {
 463         pcap_t *p;
 464
 465         p = PCAP_CREATE_COMMON(ebuf, struct pcap_snit);
 466         if (p == NULL)
 467                 return (NULL);
 468
 469         p->activate_op = pcap_activate_snit;
 470         return (p);
 471 }
 472
 473 /*
 474  * XXX - there's probably a NIOCBIND error that means "that device
 475  * doesn't support NIT"; if so, we should try an NIOCBIND and use that.
 476  */
 477 static int
 478 can_be_bound(const char *name _U_)
 479 {
 480         return (1);
 481 }
 482
 483 static int
 484 get_if_flags(const char *name _U_, bpf_u_int32 *flags _U_, char *errbuf _U_)
 485 {
 486         /*
 487          * Nothing we can do.
 488          * XXX - is there a way to find out whether an adapter has
 489          * something plugged into it?
 490          */
 491         return (0);
 492 }
 493
 494 int
 495 pcap_platform_finddevs(pcap_if_list_t *devlistp, char *errbuf)
 496 {
 497         return (pcap_findalldevs_interfaces(devlistp, errbuf, can_be_bound,
 498             get_if_flags));
 499 }
 500
 501 /*
 502  * Libpcap version string.
 503  */
 504 const char *
 505 pcap_lib_version(void)
 506 {
 507         return (PCAP_VERSION_STRING);
 508 }