The Tcpdump Group git mirrors - libpcap/blob - pcap-nit.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
  22 #ifdef HAVE_CONFIG_H
  23 #include <config.h>
  24 #endif
  25
  26 #include <sys/types.h>
  27 #include <sys/time.h>
  28 #include <sys/timeb.h>
  29 #include <sys/file.h>
  30 #include <sys/ioctl.h>
  31 #include <sys/socket.h>
  32
  33 #include <net/if.h>
  34 #include <net/nit.h>
  35
  36 #include <netinet/in.h>
  37 #include <netinet/in_systm.h>
  38 #include <netinet/ip.h>
  39 #include <netinet/if_ether.h>
  40 #include <netinet/ip_var.h>
  41 #include <netinet/udp.h>
  42 #include <netinet/udp_var.h>
  43 #include <netinet/tcp.h>
  44 #include <netinet/tcpip.h>
  45
  46 #include <errno.h>
  47 #include <stdio.h>
  48
  49 #include "pcap-int.h"
  50
  51 #ifdef HAVE_OS_PROTO_H
  52 #include "os-proto.h"
  53 #endif
  54
  55 /*
  56  * The chunk size for NIT.  This is the amount of buffering
  57  * done for read calls.
  58  */
  59 #define CHUNKSIZE (2*1024)
  60
  61 /*
  62  * The total buffer space used by NIT.
  63  */
  64 #define BUFSPACE (4*CHUNKSIZE)
  65
  66 /* Forwards */
  67 static int nit_setflags(int, int, int, char *);
  68
  69 /*
  70  * Private data for capturing on NIT devices.
  71  */
  72 struct pcap_nit {
  73         struct pcap_stat stat;
  74 };
  75
  76 static int
  77 pcap_stats_nit(pcap_t *p, struct pcap_stat *ps)
  78 {
  79         struct pcap_nit *pn = p->priv;
  80
  81         /*
  82          * "ps_recv" counts packets handed to the filter, not packets
  83          * that passed the filter.  As filtering is done in userland,
  84          * this does not include packets dropped because we ran out
  85          * of buffer space.
  86          *
  87          * "ps_drop" presumably counts packets dropped by the socket
  88          * because of flow control requirements or resource exhaustion;
  89          * it doesn't count packets dropped by the interface driver.
  90          * As filtering is done in userland, it counts packets regardless
  91          * of whether they would've passed the filter.
  92          *
  93          * These statistics don't include packets not yet read from the
  94          * kernel by libpcap or packets not yet read from libpcap by the
  95          * application.
  96          */
  97         *ps = pn->stat;
  98         return (0);
  99 }
 100
 101 static int
 102 pcap_read_nit(pcap_t *p, int cnt, pcap_handler callback, u_char *user)
 103 {
 104         struct pcap_nit *pn = p->priv;
 105         register int cc, n;
 106         register u_char *bp, *cp, *ep;
 107         register struct nit_hdr *nh;
 108         register int caplen;
 109
 110         cc = p->cc;
 111         if (cc == 0) {
 112                 cc = read(p->fd, (char *)p->buffer, p->bufsize);
 113                 if (cc < 0) {
 114                         if (errno == EWOULDBLOCK)
 115                                 return (0);
 116                         pcap_fmt_errmsg_for_errno(p->errbuf, sizeof(p->errbuf),
 117                             errno, "pcap_read");
 118                         return (-1);
 119                 }
 120                 bp = (u_char *)p->buffer;
 121         } else
 122                 bp = p->bp;
 123
 124         /*
 125          * Loop through each packet.  The increment expression
 126          * rounds up to the next int boundary past the end of
 127          * the previous packet.
 128          */
 129         n = 0;
 130         ep = bp + cc;
 131         while (bp < ep) {
 132                 /*
 133                  * Has "pcap_breakloop()" been called?
 134                  * If so, return immediately - if we haven't read any
 135                  * packets, clear the flag and return -2 to indicate
 136                  * that we were told to break out of the loop, otherwise
 137                  * leave the flag set, so that the *next* call will break
 138                  * out of the loop without having read any packets, and
 139                  * return the number of packets we've processed so far.
 140                  */
 141                 if (p->break_loop) {
 142                         if (n == 0) {
 143                                 p->break_loop = 0;
 144                                 return (-2);
 145                         } else {
 146                                 p->cc = ep - bp;
 147                                 p->bp = bp;
 148                                 return (n);
 149                         }
 150                 }
 151
 152                 nh = (struct nit_hdr *)bp;
 153                 cp = bp + sizeof(*nh);
 154
 155                 switch (nh->nh_state) {
 156
 157                 case NIT_CATCH:
 158                         break;
 159
 160                 case NIT_NOMBUF:
 161                 case NIT_NOCLUSTER:
 162                 case NIT_NOSPACE:
 163                         pn->stat.ps_drop = nh->nh_dropped;
 164                         continue;
 165
 166                 case NIT_SEQNO:
 167                         continue;
 168
 169                 default:
 170                         snprintf(p->errbuf, sizeof(p->errbuf),
 171                             "bad nit state %d", nh->nh_state);
 172                         return (-1);
 173                 }
 174                 ++pn->stat.ps_recv;
 175                 bp += ((sizeof(struct nit_hdr) + nh->nh_datalen +
 176                     sizeof(int) - 1) & ~(sizeof(int) - 1));
 177
 178                 caplen = nh->nh_wirelen;
 179                 if (caplen > p->snapshot)
 180                         caplen = p->snapshot;
 181                 if (pcap_filter(p->fcode.bf_insns, cp, nh->nh_wirelen, caplen)) {
 182                         struct pcap_pkthdr h;
 183                         h.ts = nh->nh_timestamp;
 184                         h.len = nh->nh_wirelen;
 185                         h.caplen = caplen;
 186                         (*callback)(user, &h, cp);
 187                         if (++n >= cnt && !PACKET_COUNT_IS_UNLIMITED(cnt)) {
 188                                 p->cc = ep - bp;
 189                                 p->bp = bp;
 190                                 return (n);
 191                         }
 192                 }
 193         }
 194         p->cc = 0;
 195         return (n);
 196 }
 197
 198 static int
 199 pcap_inject_nit(pcap_t *p, const void *buf, int size)
 200 {
 201         struct sockaddr sa;
 202         int ret;
 203
 204         memset(&sa, 0, sizeof(sa));
 205         strncpy(sa.sa_data, device, sizeof(sa.sa_data));
 206         ret = sendto(p->fd, buf, size, 0, &sa, sizeof(sa));
 207         if (ret == -1) {
 208                 pcap_fmt_errmsg_for_errno(p->errbuf, PCAP_ERRBUF_SIZE,
 209                     errno, "send");
 210                 return (-1);
 211         }
 212         return (ret);
 213 }
 214
 215 static int
 216 nit_setflags(pcap_t *p)
 217 {
 218         struct nit_ioc nioc;
 219
 220         memset(&nioc, 0, sizeof(nioc));
 221         nioc.nioc_typetomatch = NT_ALLTYPES;
 222         nioc.nioc_snaplen = p->snapshot;
 223         nioc.nioc_bufalign = sizeof(int);
 224         nioc.nioc_bufoffset = 0;
 225
 226         if (p->opt.buffer_size != 0)
 227                 nioc.nioc_bufspace = p->opt.buffer_size;
 228         else {
 229                 /* Default buffer size */
 230                 nioc.nioc_bufspace = BUFSPACE;
 231         }
 232
 233         if (p->opt.immediate) {
 234                 /*
 235                  * XXX - will this cause packets to be delivered immediately?
 236                  * XXX - given that this is for SunOS prior to 4.0, do
 237                  * we care?
 238                  */
 239                 nioc.nioc_chunksize = 0;
 240         } else
 241                 nioc.nioc_chunksize = CHUNKSIZE;
 242         if (p->opt.timeout != 0) {
 243                 nioc.nioc_flags |= NF_TIMEOUT;
 244                 nioc.nioc_timeout.tv_sec = p->opt.timeout / 1000;
 245                 nioc.nioc_timeout.tv_usec = (p->opt.timeout * 1000) % 1000000;
 246         }
 247         if (p->opt.promisc)
 248                 nioc.nioc_flags |= NF_PROMISC;
 249
 250         if (ioctl(p->fd, SIOCSNIT, &nioc) < 0) {
 251                 pcap_fmt_errmsg_for_errno(p->errbuf, PCAP_ERRBUF_SIZE,
 252                     errno, "SIOCSNIT");
 253                 return (-1);
 254         }
 255         return (0);
 256 }
 257
 258 static int
 259 pcap_activate_nit(pcap_t *p)
 260 {
 261         int fd;
 262         struct sockaddr_nit snit;
 263
 264         if (p->opt.rfmon) {
 265                 /*
 266                  * No monitor mode on SunOS 3.x or earlier (no
 267                  * Wi-Fi *devices* for the hardware that supported
 268                  * them!).
 269                  */
 270                 return (PCAP_ERROR_RFMON_NOTSUP);
 271         }
 272
 273         /*
 274          * Turn a negative snapshot value (invalid), a snapshot value of
 275          * 0 (unspecified), or a value bigger than the normal maximum
 276          * value, into the maximum allowed value.
 277          *
 278          * If some application really *needs* a bigger snapshot
 279          * length, we should just increase MAXIMUM_SNAPLEN.
 280          */
 281         if (p->snapshot <= 0 || p->snapshot > MAXIMUM_SNAPLEN)
 282                 p->snapshot = MAXIMUM_SNAPLEN;
 283
 284         if (p->snapshot < 96)
 285                 /*
 286                  * NIT requires a snapshot length of at least 96.
 287                  */
 288                 p->snapshot = 96;
 289
 290         memset(p, 0, sizeof(*p));
 291         p->fd = fd = socket(AF_NIT, SOCK_RAW, NITPROTO_RAW);
 292         if (fd < 0) {
 293                 pcap_fmt_errmsg_for_errno(p->errbuf, PCAP_ERRBUF_SIZE,
 294                     errno, "socket");
 295                 goto bad;
 296         }
 297         snit.snit_family = AF_NIT;
 298         (void)strncpy(snit.snit_ifname, p->opt.device, NITIFSIZ);
 299
 300         if (bind(fd, (struct sockaddr *)&snit, sizeof(snit))) {
 301                 /*
 302                  * XXX - there's probably a particular bind error that
 303                  * means "there's no such device" and a particular bind
 304                  * error that means "that device doesn't support NIT";
 305                  * they might be the same error, if they both end up
 306                  * meaning "NIT doesn't know about that device".
 307                  */
 308                 pcap_fmt_errmsg_for_errno(p->errbuf, PCAP_ERRBUF_SIZE,
 309                     errno, "bind: %s", snit.snit_ifname);
 310                 goto bad;
 311         }
 312         if (nit_setflags(p) < 0)
 313                 goto bad;
 314
 315         /*
 316          * NIT supports only ethernets.
 317          */
 318         p->linktype = DLT_EN10MB;
 319
 320         p->bufsize = BUFSPACE;
 321         p->buffer = malloc(p->bufsize);
 322         if (p->buffer == NULL) {
 323                 pcap_fmt_errmsg_for_errno(p->errbuf, PCAP_ERRBUF_SIZE,
 324                     errno, "malloc");
 325                 goto bad;
 326         }
 327
 328         /*
 329          * "p->fd" is a socket, so "select()" should work on it.
 330          */
 331         p->selectable_fd = p->fd;
 332
 333         /*
 334          * This is (presumably) a real Ethernet capture; give it a
 335          * link-layer-type list with DLT_EN10MB and DLT_DOCSIS, so
 336          * that an application can let you choose it, in case you're
 337          * capturing DOCSIS traffic that a Cisco Cable Modem
 338          * Termination System is putting out onto an Ethernet (it
 339          * doesn't put an Ethernet header onto the wire, it puts raw
 340          * DOCSIS frames out on the wire inside the low-level
 341          * Ethernet framing).
 342          */
 343         p->dlt_list = (u_int *) malloc(sizeof(u_int) * 2);
 344         /*
 345          * If that fails, just leave the list empty.
 346          */
 347         if (p->dlt_list != NULL) {
 348                 p->dlt_list[0] = DLT_EN10MB;
 349                 p->dlt_list[1] = DLT_DOCSIS;
 350                 p->dlt_count = 2;
 351         }
 352
 353         p->read_op = pcap_read_nit;
 354         p->inject_op = pcap_inject_nit;
 355         p->setfilter_op = install_bpf_program;  /* no kernel filtering */
 356         p->setdirection_op = NULL;      /* Not implemented. */
 357         p->set_datalink_op = NULL;      /* can't change data link type */
 358         p->getnonblock_op = pcap_getnonblock_fd;
 359         p->setnonblock_op = pcap_setnonblock_fd;
 360         p->stats_op = pcap_stats_nit;
 361
 362         return (0);
 363  bad:
 364         pcap_cleanup_live_common(p);
 365         return (PCAP_ERROR);
 366 }
 367
 368 pcap_t *
 369 pcap_create_interface(const char *device _U_, char *ebuf)
 370 {
 371         pcap_t *p;
 372
 373         p = PCAP_CREATE_COMMON(ebuf, struct pcap_nit);
 374         if (p == NULL)
 375                 return (NULL);
 376
 377         p->activate_op = pcap_activate_nit;
 378         return (p);
 379 }
 380
 381 /*
 382  * XXX - there's probably a particular bind error that means "that device
 383  * doesn't support NIT"; if so, we should try a bind and use that.
 384  */
 385 static int
 386 can_be_bound(const char *name _U_)
 387 {
 388         return (1);
 389 }
 390
 391 static int
 392 get_if_flags(const char *name _U_, bpf_u_int32 *flags _U_, char *errbuf _U_)
 393 {
 394         /*
 395          * Nothing we can do.
 396          * XXX - is there a way to find out whether an adapter has
 397          * something plugged into it?
 398          */
 399         return (0);
 400 }
 401
 402 int
 403 pcap_platform_finddevs(pcap_if_list_t *devlistp, char *errbuf)
 404 {
 405         return (pcap_findalldevs_interfaces(devlistp, errbuf, can_be_bound,
 406             get_if_flags));
 407 }
 408
 409 /*
 410  * Libpcap version string.
 411  */
 412 const char *
 413 pcap_lib_version(void)
 414 {
 415         return (PCAP_VERSION_STRING);
 416 }