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 <ctype.h>
  57 #include <errno.h>
  58 #include <stdio.h>
  59 #include <string.h>
  60 #include <unistd.h>
  61
  62 #include "pcap-int.h"
  63
  64 #ifdef HAVE_OS_PROTO_H
  65 #include "os-proto.h"
  66 #endif
  67
  68 /*
  69  * The chunk size for NIT.  This is the amount of buffering
  70  * done for read calls.
  71  */
  72 #define CHUNKSIZE (2*1024)
  73
  74 /*
  75  * The total buffer space used by NIT.
  76  */
  77 #define BUFSPACE (4*CHUNKSIZE)
  78
  79 /* Forwards */
  80 static int nit_setflags(int, int, int, char *);
  81
  82 /*
  83  * Private data for capturing on STREAMS NIT devices.
  84  */
  85 struct pcap_snit {
  86         struct pcap_stat stat;
  87 };
  88
  89 static int
  90 pcap_stats_snit(pcap_t *p, struct pcap_stat *ps)
  91 {
  92         struct pcap_snit *psn = p->priv;
  93
  94         /*
  95          * "ps_recv" counts packets handed to the filter, not packets
  96          * that passed the filter.  As filtering is done in userland,
  97          * this does not include packets dropped because we ran out
  98          * of buffer space.
  99          *
 100          * "ps_drop" counts packets dropped inside the "/dev/nit"
 101          * device because of flow control requirements or resource
 102          * exhaustion; it doesn't count packets dropped by the
 103          * interface driver, or packets dropped upstream.  As filtering
 104          * is done in userland, it counts packets regardless of whether
 105          * they would've passed the filter.
 106          *
 107          * These statistics don't include packets not yet read from the
 108          * kernel by libpcap or packets not yet read from libpcap by the
 109          * application.
 110          */
 111         *ps = psn->stat;
 112         return (0);
 113 }
 114
 115 static int
 116 pcap_read_snit(pcap_t *p, int cnt, pcap_handler callback, u_char *user)
 117 {
 118         struct pcap_snit *psn = p->priv;
 119         register int cc, n;
 120         register u_char *bp, *cp, *ep;
 121         register struct nit_bufhdr *hdrp;
 122         register struct nit_iftime *ntp;
 123         register struct nit_iflen *nlp;
 124         register struct nit_ifdrops *ndp;
 125         register int caplen;
 126
 127         cc = p->cc;
 128         if (cc == 0) {
 129                 cc = read(p->fd, (char *)p->buffer, p->bufsize);
 130                 if (cc < 0) {
 131                         if (errno == EWOULDBLOCK)
 132                                 return (0);
 133                         pcap_snprintf(p->errbuf, sizeof(p->errbuf), "pcap_read: %s",
 134                                 pcap_strerror(errno));
 135                         return (-1);
 136                 }
 137                 bp = (u_char *)p->buffer;
 138         } else
 139                 bp = p->bp;
 140
 141         /*
 142          * loop through each snapshot in the chunk
 143          */
 144         n = 0;
 145         ep = bp + cc;
 146         while (bp < ep) {
 147                 /*
 148                  * Has "pcap_breakloop()" been called?
 149                  * If so, return immediately - if we haven't read any
 150                  * packets, clear the flag and return -2 to indicate
 151                  * that we were told to break out of the loop, otherwise
 152                  * leave the flag set, so that the *next* call will break
 153                  * out of the loop without having read any packets, and
 154                  * return the number of packets we've processed so far.
 155                  */
 156                 if (p->break_loop) {
 157                         if (n == 0) {
 158                                 p->break_loop = 0;
 159                                 return (-2);
 160                         } else {
 161                                 p->bp = bp;
 162                                 p->cc = ep - bp;
 163                                 return (n);
 164                         }
 165                 }
 166
 167                 ++psn->stat.ps_recv;
 168                 cp = bp;
 169
 170                 /* get past NIT buffer  */
 171                 hdrp = (struct nit_bufhdr *)cp;
 172                 cp += sizeof(*hdrp);
 173
 174                 /* get past NIT timer   */
 175                 ntp = (struct nit_iftime *)cp;
 176                 cp += sizeof(*ntp);
 177
 178                 ndp = (struct nit_ifdrops *)cp;
 179                 psn->stat.ps_drop = ndp->nh_drops;
 180                 cp += sizeof *ndp;
 181
 182                 /* get past packet len  */
 183                 nlp = (struct nit_iflen *)cp;
 184                 cp += sizeof(*nlp);
 185
 186                 /* next snapshot        */
 187                 bp += hdrp->nhb_totlen;
 188
 189                 caplen = nlp->nh_pktlen;
 190                 if (caplen > p->snapshot)
 191                         caplen = p->snapshot;
 192
 193                 if (bpf_filter(p->fcode.bf_insns, cp, nlp->nh_pktlen, caplen)) {
 194                         struct pcap_pkthdr h;
 195                         h.ts = ntp->nh_timestamp;
 196                         h.len = nlp->nh_pktlen;
 197                         h.caplen = caplen;
 198                         (*callback)(user, &h, cp);
 199                         if (++n >= cnt && !PACKET_COUNT_IS_UNLIMITED(cnt)) {
 200                                 p->cc = ep - bp;
 201                                 p->bp = bp;
 202                                 return (n);
 203                         }
 204                 }
 205         }
 206         p->cc = 0;
 207         return (n);
 208 }
 209
 210 static int
 211 pcap_inject_snit(pcap_t *p, const void *buf, size_t size)
 212 {
 213         struct strbuf ctl, data;
 214
 215         /*
 216          * XXX - can we just do
 217          *
 218         ret = write(pd->f, buf, size);
 219          */
 220         ctl.len = sizeof(*sa);  /* XXX - what was this? */
 221         ctl.buf = (char *)sa;
 222         data.buf = buf;
 223         data.len = size;
 224         ret = putmsg(p->fd, &ctl, &data);
 225         if (ret == -1) {
 226                 pcap_snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "send: %s",
 227                     pcap_strerror(errno));
 228                 return (-1);
 229         }
 230         return (ret);
 231 }
 232
 233 static int
 234 nit_setflags(pcap_t *p)
 235 {
 236         bpf_u_int32 flags;
 237         struct strioctl si;
 238         u_int zero = 0;
 239         struct timeval timeout;
 240
 241         if (p->opt.immediate) {
 242                 /*
 243                  * Set the chunk size to zero, so that chunks get sent
 244                  * up immediately.
 245                  */
 246                 si.ic_cmd = NIOCSCHUNK;
 247                 si.ic_len = sizeof(zero);
 248                 si.ic_dp = (char *)&zero;
 249                 if (ioctl(p->fd, I_STR, (char *)&si) < 0) {
 250                         pcap_snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "NIOCSCHUNK: %s",
 251                             pcap_strerror(errno));
 252                         return (-1);
 253                 }
 254         }
 255         si.ic_timout = INFTIM;
 256         if (p->opt.timeout != 0) {
 257                 timeout.tv_sec = p->opt.timeout / 1000;
 258                 timeout.tv_usec = (p->opt.timeout * 1000) % 1000000;
 259                 si.ic_cmd = NIOCSTIME;
 260                 si.ic_len = sizeof(timeout);
 261                 si.ic_dp = (char *)&timeout;
 262                 if (ioctl(p->fd, I_STR, (char *)&si) < 0) {
 263                         pcap_snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "NIOCSTIME: %s",
 264                             pcap_strerror(errno));
 265                         return (-1);
 266                 }
 267         }
 268         flags = NI_TIMESTAMP | NI_LEN | NI_DROPS;
 269         if (p->opt.promisc)
 270                 flags |= NI_PROMISC;
 271         si.ic_cmd = NIOCSFLAGS;
 272         si.ic_len = sizeof(flags);
 273         si.ic_dp = (char *)&flags;
 274         if (ioctl(p->fd, I_STR, (char *)&si) < 0) {
 275                 pcap_snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "NIOCSFLAGS: %s",
 276                     pcap_strerror(errno));
 277                 return (-1);
 278         }
 279         return (0);
 280 }
 281
 282 static int
 283 pcap_activate_snit(pcap_t *p)
 284 {
 285         struct strioctl si;             /* struct for ioctl() */
 286         struct ifreq ifr;               /* interface request struct */
 287         int chunksize = CHUNKSIZE;
 288         int fd;
 289         static const char dev[] = "/dev/nit";
 290
 291         if (p->opt.rfmon) {
 292                 /*
 293                  * No monitor mode on SunOS 4.x (no Wi-Fi devices on
 294                  * hardware supported by SunOS 4.x).
 295                  */
 296                 return (PCAP_ERROR_RFMON_NOTSUP);
 297         }
 298
 299         /*
 300          * Turn a negative snapshot value (invalid), a snapshot value of
 301          * 0 (unspecified), or a value bigger than the normal maximum
 302          * value, into the maximum allowed value.
 303          *
 304          * If some application really *needs* a bigger snapshot
 305          * length, we should just increase MAXIMUM_SNAPLEN.
 306          */
 307         if (p->snapshot <= 0 || p->snapshot > MAXIMUM_SNAPLEN)
 308                 p->snapshot = MAXIMUM_SNAPLEN;
 309
 310         if (p->snapshot < 96)
 311                 /*
 312                  * NIT requires a snapshot length of at least 96.
 313                  */
 314                 p->snapshot = 96;
 315
 316         /*
 317          * Initially try a read/write open (to allow the inject
 318          * method to work).  If that fails due to permission
 319          * issues, fall back to read-only.  This allows a
 320          * non-root user to be granted specific access to pcap
 321          * capabilities via file permissions.
 322          *
 323          * XXX - we should have an API that has a flag that
 324          * controls whether to open read-only or read-write,
 325          * so that denial of permission to send (or inability
 326          * to send, if sending packets isn't supported on
 327          * the device in question) can be indicated at open
 328          * time.
 329          */
 330         p->fd = fd = open(dev, O_RDWR);
 331         if (fd < 0 && errno == EACCES)
 332                 p->fd = fd = open(dev, O_RDONLY);
 333         if (fd < 0) {
 334                 pcap_snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "%s: %s", dev,
 335                     pcap_strerror(errno));
 336                 goto bad;
 337         }
 338
 339         /* arrange to get discrete messages from the STREAM and use NIT_BUF */
 340         if (ioctl(fd, I_SRDOPT, (char *)RMSGD) < 0) {
 341                 pcap_snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "I_SRDOPT: %s",
 342                     pcap_strerror(errno));
 343                 goto bad;
 344         }
 345         if (ioctl(fd, I_PUSH, "nbuf") < 0) {
 346                 pcap_snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "push nbuf: %s",
 347                     pcap_strerror(errno));
 348                 goto bad;
 349         }
 350         /* set the chunksize */
 351         si.ic_cmd = NIOCSCHUNK;
 352         si.ic_timout = INFTIM;
 353         si.ic_len = sizeof(chunksize);
 354         si.ic_dp = (char *)&chunksize;
 355         if (ioctl(fd, I_STR, (char *)&si) < 0) {
 356                 pcap_snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "NIOCSCHUNK: %s",
 357                     pcap_strerror(errno));
 358                 goto bad;
 359         }
 360
 361         /* request the interface */
 362         strncpy(ifr.ifr_name, p->opt.device, sizeof(ifr.ifr_name));
 363         ifr.ifr_name[sizeof(ifr.ifr_name) - 1] = '\0';
 364         si.ic_cmd = NIOCBIND;
 365         si.ic_len = sizeof(ifr);
 366         si.ic_dp = (char *)&ifr;
 367         if (ioctl(fd, I_STR, (char *)&si) < 0) {
 368                 /*
 369                  * XXX - is there an error that means "no such device"?
 370                  * Is there one that means "that device doesn't support
 371                  * STREAMS NIT"?
 372                  */
 373                 pcap_snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "NIOCBIND: %s: %s",
 374                         ifr.ifr_name, pcap_strerror(errno));
 375                 goto bad;
 376         }
 377
 378         /* set the snapshot length */
 379         si.ic_cmd = NIOCSSNAP;
 380         si.ic_len = sizeof(p->snapshot);
 381         si.ic_dp = (char *)&p->snapshot;
 382         if (ioctl(fd, I_STR, (char *)&si) < 0) {
 383                 pcap_snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "NIOCSSNAP: %s",
 384                     pcap_strerror(errno));
 385                 goto bad;
 386         }
 387         if (nit_setflags(p) < 0)
 388                 goto bad;
 389
 390         (void)ioctl(fd, I_FLUSH, (char *)FLUSHR);
 391         /*
 392          * NIT supports only ethernets.
 393          */
 394         p->linktype = DLT_EN10MB;
 395
 396         p->bufsize = BUFSPACE;
 397         p->buffer = malloc(p->bufsize);
 398         if (p->buffer == NULL) {
 399                 strlcpy(p->errbuf, pcap_strerror(errno), PCAP_ERRBUF_SIZE);
 400                 goto bad;
 401         }
 402
 403         /*
 404          * "p->fd" is an FD for a STREAMS device, so "select()" and
 405          * "poll()" should work on it.
 406          */
 407         p->selectable_fd = p->fd;
 408
 409         /*
 410          * This is (presumably) a real Ethernet capture; give it a
 411          * link-layer-type list with DLT_EN10MB and DLT_DOCSIS, so
 412          * that an application can let you choose it, in case you're
 413          * capturing DOCSIS traffic that a Cisco Cable Modem
 414          * Termination System is putting out onto an Ethernet (it
 415          * doesn't put an Ethernet header onto the wire, it puts raw
 416          * DOCSIS frames out on the wire inside the low-level
 417          * Ethernet framing).
 418          */
 419         p->dlt_list = (u_int *) malloc(sizeof(u_int) * 2);
 420         /*
 421          * If that fails, just leave the list empty.
 422          */
 423         if (p->dlt_list != NULL) {
 424                 p->dlt_list[0] = DLT_EN10MB;
 425                 p->dlt_list[1] = DLT_DOCSIS;
 426                 p->dlt_count = 2;
 427         }
 428
 429         p->read_op = pcap_read_snit;
 430         p->inject_op = pcap_inject_snit;
 431         p->setfilter_op = install_bpf_program;  /* no kernel filtering */
 432         p->setdirection_op = NULL;      /* Not implemented. */
 433         p->set_datalink_op = NULL;      /* can't change data link type */
 434         p->getnonblock_op = pcap_getnonblock_fd;
 435         p->setnonblock_op = pcap_setnonblock_fd;
 436         p->stats_op = pcap_stats_snit;
 437
 438         return (0);
 439  bad:
 440         pcap_cleanup_live_common(p);
 441         return (PCAP_ERROR);
 442 }
 443
 444 pcap_t *
 445 pcap_create_interface(const char *device _U_, char *ebuf)
 446 {
 447         pcap_t *p;
 448
 449         p = pcap_create_common(ebuf, sizeof (struct pcap_snit));
 450         if (p == NULL)
 451                 return (NULL);
 452
 453         p->activate_op = pcap_activate_snit;
 454         return (p);
 455 }
 456
 457 /*
 458  * XXX - there's probably a NIOCBIND error that means "that device
 459  * doesn't support NIT"; if so, we should try an NIOCBIND and use that.
 460  */
 461 static int
 462 can_be_bound(const char *name _U_)
 463 {
 464         return (1);
 465 }
 466
 467 int
 468 pcap_platform_finddevs(pcap_if_list_t *devlistp, char *errbuf)
 469 {
 470         return (pcap_findalldevs_interfaces(devlistp, errbuf, can_be_bound));
 471 }
 472
 473 #include "pcap_version.h"
 474
 475 /*
 476  * Libpcap version string.
 477  */
 478 const char *
 479 pcap_lib_version(void)
 480 {
 481         return (PCAP_VERSION_STRING);
 482 }