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          * This assumes that a single buffer of packets will have
 130          * <= INT_MAX packets, so the packet count doesn't overflow.
 131          */
 132         n = 0;
 133         ep = bp + cc;
 134         while (bp < ep) {
 135                 /*
 136                  * Has "pcap_breakloop()" been called?
 137                  * If so, return immediately - if we haven't read any
 138                  * packets, clear the flag and return -2 to indicate
 139                  * that we were told to break out of the loop, otherwise
 140                  * leave the flag set, so that the *next* call will break
 141                  * out of the loop without having read any packets, and
 142                  * return the number of packets we've processed so far.
 143                  */
 144                 if (p->break_loop) {
 145                         if (n == 0) {
 146                                 p->break_loop = 0;
 147                                 return (-2);
 148                         } else {
 149                                 p->cc = ep - bp;
 150                                 p->bp = bp;
 151                                 return (n);
 152                         }
 153                 }
 154
 155                 nh = (struct nit_hdr *)bp;
 156                 cp = bp + sizeof(*nh);
 157
 158                 switch (nh->nh_state) {
 159
 160                 case NIT_CATCH:
 161                         break;
 162
 163                 case NIT_NOMBUF:
 164                 case NIT_NOCLUSTER:
 165                 case NIT_NOSPACE:
 166                         pn->stat.ps_drop = nh->nh_dropped;
 167                         continue;
 168
 169                 case NIT_SEQNO:
 170                         continue;
 171
 172                 default:
 173                         snprintf(p->errbuf, sizeof(p->errbuf),
 174                             "bad nit state %d", nh->nh_state);
 175                         return (-1);
 176                 }
 177                 ++pn->stat.ps_recv;
 178                 bp += ((sizeof(struct nit_hdr) + nh->nh_datalen +
 179                     sizeof(int) - 1) & ~(sizeof(int) - 1));
 180
 181                 caplen = nh->nh_wirelen;
 182                 if (caplen > p->snapshot)
 183                         caplen = p->snapshot;
 184                 if (pcap_filter(p->fcode.bf_insns, cp, nh->nh_wirelen, caplen)) {
 185                         struct pcap_pkthdr h;
 186                         h.ts = nh->nh_timestamp;
 187                         h.len = nh->nh_wirelen;
 188                         h.caplen = caplen;
 189                         (*callback)(user, &h, cp);
 190                         if (++n >= cnt && !PACKET_COUNT_IS_UNLIMITED(cnt)) {
 191                                 p->cc = ep - bp;
 192                                 p->bp = bp;
 193                                 return (n);
 194                         }
 195                 }
 196         }
 197         p->cc = 0;
 198         return (n);
 199 }
 200
 201 static int
 202 pcap_inject_nit(pcap_t *p, const void *buf, int size)
 203 {
 204         struct sockaddr sa;
 205         int ret;
 206
 207         memset(&sa, 0, sizeof(sa));
 208         strncpy(sa.sa_data, device, sizeof(sa.sa_data));
 209         ret = sendto(p->fd, buf, size, 0, &sa, sizeof(sa));
 210         if (ret == -1) {
 211                 pcap_fmt_errmsg_for_errno(p->errbuf, PCAP_ERRBUF_SIZE,
 212                     errno, "send");
 213                 return (-1);
 214         }
 215         return (ret);
 216 }
 217
 218 static int
 219 nit_setflags(pcap_t *p)
 220 {
 221         struct nit_ioc nioc;
 222
 223         memset(&nioc, 0, sizeof(nioc));
 224         nioc.nioc_typetomatch = NT_ALLTYPES;
 225         nioc.nioc_snaplen = p->snapshot;
 226         nioc.nioc_bufalign = sizeof(int);
 227         nioc.nioc_bufoffset = 0;
 228
 229         if (p->opt.buffer_size != 0)
 230                 nioc.nioc_bufspace = p->opt.buffer_size;
 231         else {
 232                 /* Default buffer size */
 233                 nioc.nioc_bufspace = BUFSPACE;
 234         }
 235
 236         if (p->opt.immediate) {
 237                 /*
 238                  * XXX - will this cause packets to be delivered immediately?
 239                  * XXX - given that this is for SunOS prior to 4.0, do
 240                  * we care?
 241                  */
 242                 nioc.nioc_chunksize = 0;
 243         } else
 244                 nioc.nioc_chunksize = CHUNKSIZE;
 245         if (p->opt.timeout != 0) {
 246                 nioc.nioc_flags |= NF_TIMEOUT;
 247                 nioc.nioc_timeout.tv_sec = p->opt.timeout / 1000;
 248                 nioc.nioc_timeout.tv_usec = (p->opt.timeout * 1000) % 1000000;
 249         }
 250         if (p->opt.promisc)
 251                 nioc.nioc_flags |= NF_PROMISC;
 252
 253         if (ioctl(p->fd, SIOCSNIT, &nioc) < 0) {
 254                 pcap_fmt_errmsg_for_errno(p->errbuf, PCAP_ERRBUF_SIZE,
 255                     errno, "SIOCSNIT");
 256                 return (-1);
 257         }
 258         return (0);
 259 }
 260
 261 static int
 262 pcap_activate_nit(pcap_t *p)
 263 {
 264         int fd;
 265         struct sockaddr_nit snit;
 266
 267         if (p->opt.rfmon) {
 268                 /*
 269                  * No monitor mode on SunOS 3.x or earlier (no
 270                  * Wi-Fi *devices* for the hardware that supported
 271                  * them!).
 272                  */
 273                 return (PCAP_ERROR_RFMON_NOTSUP);
 274         }
 275
 276         /*
 277          * Turn a negative snapshot value (invalid), a snapshot value of
 278          * 0 (unspecified), or a value bigger than the normal maximum
 279          * value, into the maximum allowed value.
 280          *
 281          * If some application really *needs* a bigger snapshot
 282          * length, we should just increase MAXIMUM_SNAPLEN.
 283          */
 284         if (p->snapshot <= 0 || p->snapshot > MAXIMUM_SNAPLEN)
 285                 p->snapshot = MAXIMUM_SNAPLEN;
 286
 287         if (p->snapshot < 96)
 288                 /*
 289                  * NIT requires a snapshot length of at least 96.
 290                  */
 291                 p->snapshot = 96;
 292
 293         memset(p, 0, sizeof(*p));
 294         p->fd = fd = socket(AF_NIT, SOCK_RAW, NITPROTO_RAW);
 295         if (fd < 0) {
 296                 pcap_fmt_errmsg_for_errno(p->errbuf, PCAP_ERRBUF_SIZE,
 297                     errno, "socket");
 298                 goto bad;
 299         }
 300         snit.snit_family = AF_NIT;
 301         (void)strncpy(snit.snit_ifname, p->opt.device, NITIFSIZ);
 302
 303         if (bind(fd, (struct sockaddr *)&snit, sizeof(snit))) {
 304                 /*
 305                  * XXX - there's probably a particular bind error that
 306                  * means "there's no such device" and a particular bind
 307                  * error that means "that device doesn't support NIT";
 308                  * they might be the same error, if they both end up
 309                  * meaning "NIT doesn't know about that device".
 310                  */
 311                 pcap_fmt_errmsg_for_errno(p->errbuf, PCAP_ERRBUF_SIZE,
 312                     errno, "bind: %s", snit.snit_ifname);
 313                 goto bad;
 314         }
 315         if (nit_setflags(p) < 0)
 316                 goto bad;
 317
 318         /*
 319          * NIT supports only ethernets.
 320          */
 321         p->linktype = DLT_EN10MB;
 322
 323         p->bufsize = BUFSPACE;
 324         p->buffer = malloc(p->bufsize);
 325         if (p->buffer == NULL) {
 326                 pcap_fmt_errmsg_for_errno(p->errbuf, PCAP_ERRBUF_SIZE,
 327                     errno, "malloc");
 328                 goto bad;
 329         }
 330
 331         /*
 332          * "p->fd" is a socket, so "select()" should work on it.
 333          */
 334         p->selectable_fd = p->fd;
 335
 336         /*
 337          * This is (presumably) a real Ethernet capture; give it a
 338          * link-layer-type list with DLT_EN10MB and DLT_DOCSIS, so
 339          * that an application can let you choose it, in case you're
 340          * capturing DOCSIS traffic that a Cisco Cable Modem
 341          * Termination System is putting out onto an Ethernet (it
 342          * doesn't put an Ethernet header onto the wire, it puts raw
 343          * DOCSIS frames out on the wire inside the low-level
 344          * Ethernet framing).
 345          */
 346         p->dlt_list = (u_int *) malloc(sizeof(u_int) * 2);
 347         /*
 348          * If that fails, just leave the list empty.
 349          */
 350         if (p->dlt_list != NULL) {
 351                 p->dlt_list[0] = DLT_EN10MB;
 352                 p->dlt_list[1] = DLT_DOCSIS;
 353                 p->dlt_count = 2;
 354         }
 355
 356         p->read_op = pcap_read_nit;
 357         p->inject_op = pcap_inject_nit;
 358         p->setfilter_op = install_bpf_program;  /* no kernel filtering */
 359         p->setdirection_op = NULL;      /* Not implemented. */
 360         p->set_datalink_op = NULL;      /* can't change data link type */
 361         p->getnonblock_op = pcap_getnonblock_fd;
 362         p->setnonblock_op = pcap_setnonblock_fd;
 363         p->stats_op = pcap_stats_nit;
 364
 365         return (0);
 366  bad:
 367         pcap_cleanup_live_common(p);
 368         return (PCAP_ERROR);
 369 }
 370
 371 pcap_t *
 372 pcap_create_interface(const char *device _U_, char *ebuf)
 373 {
 374         pcap_t *p;
 375
 376         p = PCAP_CREATE_COMMON(ebuf, struct pcap_nit);
 377         if (p == NULL)
 378                 return (NULL);
 379
 380         p->activate_op = pcap_activate_nit;
 381         return (p);
 382 }
 383
 384 /*
 385  * XXX - there's probably a particular bind error that means "that device
 386  * doesn't support NIT"; if so, we should try a bind and use that.
 387  */
 388 static int
 389 can_be_bound(const char *name _U_)
 390 {
 391         return (1);
 392 }
 393
 394 static int
 395 get_if_flags(const char *name _U_, bpf_u_int32 *flags _U_, char *errbuf _U_)
 396 {
 397         /*
 398          * Nothing we can do.
 399          * XXX - is there a way to find out whether an adapter has
 400          * something plugged into it?
 401          */
 402         return (0);
 403 }
 404
 405 int
 406 pcap_platform_finddevs(pcap_if_list_t *devlistp, char *errbuf)
 407 {
 408         return (pcap_findalldevs_interfaces(devlistp, errbuf, can_be_bound,
 409             get_if_flags));
 410 }
 411
 412 /*
 413  * Libpcap version string.
 414  */
 415 const char *
 416 pcap_lib_version(void)
 417 {
 418         return (PCAP_VERSION_STRING);
 419 }