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