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 #ifndef lint
  27 static const char rcsid[] _U_ =
  28     "@(#) $Header: /tcpdump/master/libpcap/pcap-snit.c,v 1.77 2008-04-14 20:40:58 guy Exp $ (LBL)";
  29 #endif
  30
  31 #ifdef HAVE_CONFIG_H
  32 #include "config.h"
  33 #endif
  34
  35 #include <sys/types.h>
  36 #include <sys/time.h>
  37 #include <sys/timeb.h>
  38 #include <sys/dir.h>
  39 #include <sys/fcntlcom.h>
  40 #include <sys/file.h>
  41 #include <sys/ioctl.h>
  42 #include <sys/socket.h>
  43 #include <sys/stropts.h>
  44
  45 #include <net/if.h>
  46 #include <net/nit.h>
  47 #include <net/nit_if.h>
  48 #include <net/nit_pf.h>
  49 #include <net/nit_buf.h>
  50
  51 #include <netinet/in.h>
  52 #include <netinet/in_systm.h>
  53 #include <netinet/ip.h>
  54 #include <netinet/if_ether.h>
  55 #include <netinet/ip_var.h>
  56 #include <netinet/udp.h>
  57 #include <netinet/udp_var.h>
  58 #include <netinet/tcp.h>
  59 #include <netinet/tcpip.h>
  60
  61 #include <ctype.h>
  62 #include <errno.h>
  63 #include <stdio.h>
  64 #include <string.h>
  65 #include <unistd.h>
  66
  67 #include "pcap-int.h"
  68
  69 #ifdef HAVE_OS_PROTO_H
  70 #include "os-proto.h"
  71 #endif
  72
  73 /*
  74  * The chunk size for NIT.  This is the amount of buffering
  75  * done for read calls.
  76  */
  77 #define CHUNKSIZE (2*1024)
  78
  79 /*
  80  * The total buffer space used by NIT.
  81  */
  82 #define BUFSPACE (4*CHUNKSIZE)
  83
  84 /* Forwards */
  85 static int nit_setflags(int, int, int, char *);
  86
  87 static int
  88 pcap_stats_snit(pcap_t *p, struct pcap_stat *ps)
  89 {
  90
  91         /*
  92          * "ps_recv" counts packets handed to the filter, not packets
  93          * that passed the filter.  As filtering is done in userland,
  94          * this does not include packets dropped because we ran out
  95          * of buffer space.
  96          *
  97          * "ps_drop" counts packets dropped inside the "/dev/nit"
  98          * device because of flow control requirements or resource
  99          * exhaustion; it doesn't count packets dropped by the
 100          * interface driver, or packets dropped upstream.  As filtering
 101          * is done in userland, it counts packets regardless of whether
 102          * they would've passed the filter.
 103          *
 104          * These statistics don't include packets not yet read from the
 105          * kernel by libpcap or packets not yet read from libpcap by the
 106          * application.
 107          */
 108         *ps = p->md.stat;
 109         return (0);
 110 }
 111
 112 static int
 113 pcap_read_snit(pcap_t *p, int cnt, pcap_handler callback, u_char *user)
 114 {
 115         register int cc, n;
 116         register u_char *bp, *cp, *ep;
 117         register struct nit_bufhdr *hdrp;
 118         register struct nit_iftime *ntp;
 119         register struct nit_iflen *nlp;
 120         register struct nit_ifdrops *ndp;
 121         register int caplen;
 122
 123         cc = p->cc;
 124         if (cc == 0) {
 125                 cc = read(p->fd, (char *)p->buffer, p->bufsize);
 126                 if (cc < 0) {
 127                         if (errno == EWOULDBLOCK)
 128                                 return (0);
 129                         snprintf(p->errbuf, sizeof(p->errbuf), "pcap_read: %s",
 130                                 pcap_strerror(errno));
 131                         return (-1);
 132                 }
 133                 bp = p->buffer;
 134         } else
 135                 bp = p->bp;
 136
 137         /*
 138          * loop through each snapshot in the chunk
 139          */
 140         n = 0;
 141         ep = bp + cc;
 142         while (bp < ep) {
 143                 /*
 144                  * Has "pcap_breakloop()" been called?
 145                  * If so, return immediately - if we haven't read any
 146                  * packets, clear the flag and return -2 to indicate
 147                  * that we were told to break out of the loop, otherwise
 148                  * leave the flag set, so that the *next* call will break
 149                  * out of the loop without having read any packets, and
 150                  * return the number of packets we've processed so far.
 151                  */
 152                 if (p->break_loop) {
 153                         if (n == 0) {
 154                                 p->break_loop = 0;
 155                                 return (-2);
 156                         } else {
 157                                 p->bp = bp;
 158                                 p->cc = ep - bp;
 159                                 return (n);
 160                         }
 161                 }
 162
 163                 ++p->md.stat.ps_recv;
 164                 cp = bp;
 165
 166                 /* get past NIT buffer  */
 167                 hdrp = (struct nit_bufhdr *)cp;
 168                 cp += sizeof(*hdrp);
 169
 170                 /* get past NIT timer   */
 171                 ntp = (struct nit_iftime *)cp;
 172                 cp += sizeof(*ntp);
 173
 174                 ndp = (struct nit_ifdrops *)cp;
 175                 p->md.stat.ps_drop = ndp->nh_drops;
 176                 cp += sizeof *ndp;
 177
 178                 /* get past packet len  */
 179                 nlp = (struct nit_iflen *)cp;
 180                 cp += sizeof(*nlp);
 181
 182                 /* next snapshot        */
 183                 bp += hdrp->nhb_totlen;
 184
 185                 caplen = nlp->nh_pktlen;
 186                 if (caplen > p->snapshot)
 187                         caplen = p->snapshot;
 188
 189                 if (bpf_filter(p->fcode.bf_insns, cp, nlp->nh_pktlen, caplen)) {
 190                         struct pcap_pkthdr h;
 191                         h.ts = ntp->nh_timestamp;
 192                         h.len = nlp->nh_pktlen;
 193                         h.caplen = caplen;
 194                         (*callback)(user, &h, cp);
 195                         if (++n >= cnt && cnt > 0) {
 196                                 p->cc = ep - bp;
 197                                 p->bp = bp;
 198                                 return (n);
 199                         }
 200                 }
 201         }
 202         p->cc = 0;
 203         return (n);
 204 }
 205
 206 static int
 207 pcap_inject_snit(pcap_t *p, const void *buf, size_t size)
 208 {
 209         struct strbuf ctl, data;
 210
 211         /*
 212          * XXX - can we just do
 213          *
 214         ret = write(pd->f, buf, size);
 215          */
 216         ctl.len = sizeof(*sa);  /* XXX - what was this? */
 217         ctl.buf = (char *)sa;
 218         data.buf = buf;
 219         data.len = size;
 220         ret = putmsg(p->fd, &ctl, &data);
 221         if (ret == -1) {
 222                 snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "send: %s",
 223                     pcap_strerror(errno));
 224                 return (-1);
 225         }
 226         return (ret);
 227 }
 228
 229 static int
 230 nit_setflags(int fd, int promisc, int to_ms, char *ebuf)
 231 {
 232         bpf_u_int32 flags;
 233         struct strioctl si;
 234         struct timeval timeout;
 235
 236         si.ic_timout = INFTIM;
 237         if (to_ms != 0) {
 238                 timeout.tv_sec = to_ms / 1000;
 239                 timeout.tv_usec = (to_ms * 1000) % 1000000;
 240                 si.ic_cmd = NIOCSTIME;
 241                 si.ic_len = sizeof(timeout);
 242                 si.ic_dp = (char *)&timeout;
 243                 if (ioctl(fd, I_STR, (char *)&si) < 0) {
 244                         snprintf(ebuf, PCAP_ERRBUF_SIZE, "NIOCSTIME: %s",
 245                             pcap_strerror(errno));
 246                         return (-1);
 247                 }
 248         }
 249         flags = NI_TIMESTAMP | NI_LEN | NI_DROPS;
 250         if (promisc)
 251                 flags |= NI_PROMISC;
 252         si.ic_cmd = NIOCSFLAGS;
 253         si.ic_len = sizeof(flags);
 254         si.ic_dp = (char *)&flags;
 255         if (ioctl(fd, I_STR, (char *)&si) < 0) {
 256                 snprintf(ebuf, PCAP_ERRBUF_SIZE, "NIOCSFLAGS: %s",
 257                     pcap_strerror(errno));
 258                 return (-1);
 259         }
 260         return (0);
 261 }
 262
 263 static int
 264 pcap_activate_snit(pcap_t *p)
 265 {
 266         struct strioctl si;             /* struct for ioctl() */
 267         struct ifreq ifr;               /* interface request struct */
 268         int chunksize = CHUNKSIZE;
 269         int fd;
 270         static char dev[] = "/dev/nit";
 271
 272         if (p->opt.rfmon) {
 273                 /*
 274                  * No monitor mode on SunOS 4.x (no Wi-Fi devices on
 275                  * hardware supported by SunOS 4.x).
 276                  */
 277                 return (PCAP_ERROR_RFMON_NOTSUP);
 278         }
 279
 280         if (p->snapshot < 96)
 281                 /*
 282                  * NIT requires a snapshot length of at least 96.
 283                  */
 284                 p->snapshot = 96;
 285
 286         /*
 287          * Initially try a read/write open (to allow the inject
 288          * method to work).  If that fails due to permission
 289          * issues, fall back to read-only.  This allows a
 290          * non-root user to be granted specific access to pcap
 291          * capabilities via file permissions.
 292          *
 293          * XXX - we should have an API that has a flag that
 294          * controls whether to open read-only or read-write,
 295          * so that denial of permission to send (or inability
 296          * to send, if sending packets isn't supported on
 297          * the device in question) can be indicated at open
 298          * time.
 299          */
 300         p->fd = fd = open(dev, O_RDWR);
 301         if (fd < 0 && errno == EACCES)
 302                 p->fd = fd = open(dev, O_RDONLY);
 303         if (fd < 0) {
 304                 snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "%s: %s", dev,
 305                     pcap_strerror(errno));
 306                 goto bad;
 307         }
 308
 309         /* arrange to get discrete messages from the STREAM and use NIT_BUF */
 310         if (ioctl(fd, I_SRDOPT, (char *)RMSGD) < 0) {
 311                 snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "I_SRDOPT: %s",
 312                     pcap_strerror(errno));
 313                 goto bad;
 314         }
 315         if (ioctl(fd, I_PUSH, "nbuf") < 0) {
 316                 snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "push nbuf: %s",
 317                     pcap_strerror(errno));
 318                 goto bad;
 319         }
 320         /* set the chunksize */
 321         si.ic_cmd = NIOCSCHUNK;
 322         si.ic_timout = INFTIM;
 323         si.ic_len = sizeof(chunksize);
 324         si.ic_dp = (char *)&chunksize;
 325         if (ioctl(fd, I_STR, (char *)&si) < 0) {
 326                 snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "NIOCSCHUNK: %s",
 327                     pcap_strerror(errno));
 328                 goto bad;
 329         }
 330
 331         /* request the interface */
 332         strncpy(ifr.ifr_name, p->opt.source, sizeof(ifr.ifr_name));
 333         ifr.ifr_name[sizeof(ifr.ifr_name) - 1] = '\0';
 334         si.ic_cmd = NIOCBIND;
 335         si.ic_len = sizeof(ifr);
 336         si.ic_dp = (char *)&ifr;
 337         if (ioctl(fd, I_STR, (char *)&si) < 0) {
 338                 snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "NIOCBIND: %s: %s",
 339                         ifr.ifr_name, pcap_strerror(errno));
 340                 goto bad;
 341         }
 342
 343         /* set the snapshot length */
 344         si.ic_cmd = NIOCSSNAP;
 345         si.ic_len = sizeof(p->snapshot);
 346         si.ic_dp = (char *)&p->snapshot;
 347         if (ioctl(fd, I_STR, (char *)&si) < 0) {
 348                 snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "NIOCSSNAP: %s",
 349                     pcap_strerror(errno));
 350                 goto bad;
 351         }
 352         if (nit_setflags(p->fd, p->opt.promisc, p->md.timeout, p->errbuf) < 0)
 353                 goto bad;
 354
 355         (void)ioctl(fd, I_FLUSH, (char *)FLUSHR);
 356         /*
 357          * NIT supports only ethernets.
 358          */
 359         p->linktype = DLT_EN10MB;
 360
 361         p->bufsize = BUFSPACE;
 362         p->buffer = (u_char *)malloc(p->bufsize);
 363         if (p->buffer == NULL) {
 364                 strlcpy(p->errbuf, pcap_strerror(errno), PCAP_ERRBUF_SIZE);
 365                 goto bad;
 366         }
 367
 368         /*
 369          * "p->fd" is an FD for a STREAMS device, so "select()" and
 370          * "poll()" should work on it.
 371          */
 372         p->selectable_fd = p->fd;
 373
 374         /*
 375          * This is (presumably) a real Ethernet capture; give it a
 376          * link-layer-type list with DLT_EN10MB and DLT_DOCSIS, so
 377          * that an application can let you choose it, in case you're
 378          * capturing DOCSIS traffic that a Cisco Cable Modem
 379          * Termination System is putting out onto an Ethernet (it
 380          * doesn't put an Ethernet header onto the wire, it puts raw
 381          * DOCSIS frames out on the wire inside the low-level
 382          * Ethernet framing).
 383          */
 384         p->dlt_list = (u_int *) malloc(sizeof(u_int) * 2);
 385         /*
 386          * If that fails, just leave the list empty.
 387          */
 388         if (p->dlt_list != NULL) {
 389                 p->dlt_list[0] = DLT_EN10MB;
 390                 p->dlt_list[1] = DLT_DOCSIS;
 391                 p->dlt_count = 2;
 392         }
 393
 394         p->read_op = pcap_read_snit;
 395         p->inject_op = pcap_inject_snit;
 396         p->setfilter_op = install_bpf_program;  /* no kernel filtering */
 397         p->setdirection_op = NULL;      /* Not implemented. */
 398         p->set_datalink_op = NULL;      /* can't change data link type */
 399         p->getnonblock_op = pcap_getnonblock_fd;
 400         p->setnonblock_op = pcap_setnonblock_fd;
 401         p->stats_op = pcap_stats_snit;
 402
 403         return (0);
 404  bad:
 405         pcap_cleanup_live_common(p);
 406         return (PCAP_ERROR);
 407 }
 408
 409 pcap_t *
 410 pcap_create(const char *device, char *ebuf)
 411 {
 412         pcap_t *p;
 413
 414         p = pcap_create_common(device, ebuf);
 415         if (p == NULL)
 416                 return (NULL);
 417
 418         p->activate_op = pcap_activate_snit;
 419         return (p);
 420 }
 421
 422 int
 423 pcap_platform_finddevs(pcap_if_t **alldevsp, char *errbuf)
 424 {
 425         return (0);
 426 }