dist/libpcap/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: /pub/NetBSD/misc/repositories/cvsroot/src/dist/libpcap/pcap-snit.c,v 1.1.1.1 2006/02/27 15:45:49 drochner 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 struct bpf_insn *fcode = p->fcode.bf_insns;
 117         register u_char *bp, *cp, *ep;
 118         register struct nit_bufhdr *hdrp;
 119         register struct nit_iftime *ntp;
 120         register struct nit_iflen *nlp;
 121         register struct nit_ifdrops *ndp;
 122         register int caplen;
 123
 124         cc = p->cc;
 125         if (cc == 0) {
 126                 cc = read(p->fd, (char *)p->buffer, p->bufsize);
 127                 if (cc < 0) {
 128                         if (errno == EWOULDBLOCK)
 129                                 return (0);
 130                         snprintf(p->errbuf, sizeof(p->errbuf), "pcap_read: %s",
 131                                 pcap_strerror(errno));
 132                         return (-1);
 133                 }
 134                 bp = p->buffer;
 135         } else
 136                 bp = p->bp;
 137
 138         /*
 139          * loop through each snapshot in the chunk
 140          */
 141         n = 0;
 142         ep = bp + cc;
 143         while (bp < ep) {
 144                 /*
 145                  * Has "pcap_breakloop()" been called?
 146                  * If so, return immediately - if we haven't read any
 147                  * packets, clear the flag and return -2 to indicate
 148                  * that we were told to break out of the loop, otherwise
 149                  * leave the flag set, so that the *next* call will break
 150                  * out of the loop without having read any packets, and
 151                  * return the number of packets we've processed so far.
 152                  */
 153                 if (p->break_loop) {
 154                         if (n == 0) {
 155                                 p->break_loop = 0;
 156                                 return (-2);
 157                         } else {
 158                                 p->bp = bp;
 159                                 p->cc = ep - bp;
 160                                 return (n);
 161                         }
 162                 }
 163
 164                 ++p->md.stat.ps_recv;
 165                 cp = bp;
 166
 167                 /* get past NIT buffer  */
 168                 hdrp = (struct nit_bufhdr *)cp;
 169                 cp += sizeof(*hdrp);
 170
 171                 /* get past NIT timer   */
 172                 ntp = (struct nit_iftime *)cp;
 173                 cp += sizeof(*ntp);
 174
 175                 ndp = (struct nit_ifdrops *)cp;
 176                 p->md.stat.ps_drop = ndp->nh_drops;
 177                 cp += sizeof *ndp;
 178
 179                 /* get past packet len  */
 180                 nlp = (struct nit_iflen *)cp;
 181                 cp += sizeof(*nlp);
 182
 183                 /* next snapshot        */
 184                 bp += hdrp->nhb_totlen;
 185
 186                 caplen = nlp->nh_pktlen;
 187                 if (caplen > p->snapshot)
 188                         caplen = p->snapshot;
 189
 190                 if (bpf_filter(fcode, cp, nlp->nh_pktlen, caplen)) {
 191                         struct pcap_pkthdr h;
 192                         h.ts = ntp->nh_timestamp;
 193                         h.len = nlp->nh_pktlen;
 194                         h.caplen = caplen;
 195                         (*callback)(user, &h, cp);
 196                         if (++n >= cnt && cnt >= 0) {
 197                                 p->cc = ep - bp;
 198                                 p->bp = bp;
 199                                 return (n);
 200                         }
 201                 }
 202         }
 203         p->cc = 0;
 204         return (n);
 205 }
 206
 207 static int
 208 pcap_inject_snit(pcap_t *p, const void *buf, size_t size)
 209 {
 210         struct strbuf ctl, data;
 211
 212         /*
 213          * XXX - can we just do
 214          *
 215         ret = write(pd->f, buf, size);
 216          */
 217         ctl.len = sizeof(*sa);  /* XXX - what was this? */
 218         ctl.buf = (char *)sa;
 219         data.buf = buf;
 220         data.len = size;
 221         ret = putmsg(p->fd, &ctl, &data);
 222         if (ret == -1) {
 223                 snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "send: %s",
 224                     pcap_strerror(errno));
 225                 return (-1);
 226         }
 227         return (ret);
 228 }
 229
 230 static int
 231 nit_setflags(int fd, int promisc, int to_ms, char *ebuf)
 232 {
 233         bpf_u_int32 flags;
 234         struct strioctl si;
 235         struct timeval timeout;
 236
 237         si.ic_timout = INFTIM;
 238         if (to_ms != 0) {
 239                 timeout.tv_sec = to_ms / 1000;
 240                 timeout.tv_usec = (to_ms * 1000) % 1000000;
 241                 si.ic_cmd = NIOCSTIME;
 242                 si.ic_len = sizeof(timeout);
 243                 si.ic_dp = (char *)&timeout;
 244                 if (ioctl(fd, I_STR, (char *)&si) < 0) {
 245                         snprintf(ebuf, PCAP_ERRBUF_SIZE, "NIOCSTIME: %s",
 246                             pcap_strerror(errno));
 247                         return (-1);
 248                 }
 249         }
 250         flags = NI_TIMESTAMP | NI_LEN | NI_DROPS;
 251         if (promisc)
 252                 flags |= NI_PROMISC;
 253         si.ic_cmd = NIOCSFLAGS;
 254         si.ic_len = sizeof(flags);
 255         si.ic_dp = (char *)&flags;
 256         if (ioctl(fd, I_STR, (char *)&si) < 0) {
 257                 snprintf(ebuf, PCAP_ERRBUF_SIZE, "NIOCSFLAGS: %s",
 258                     pcap_strerror(errno));
 259                 return (-1);
 260         }
 261         return (0);
 262 }
 263
 264 pcap_t *
 265 pcap_open_live(const char *device, int snaplen, int promisc, int to_ms,
 266     char *ebuf)
 267 {
 268         struct strioctl si;             /* struct for ioctl() */
 269         struct ifreq ifr;               /* interface request struct */
 270         int chunksize = CHUNKSIZE;
 271         int fd;
 272         static char dev[] = "/dev/nit";
 273         register pcap_t *p;
 274
 275         p = (pcap_t *)malloc(sizeof(*p));
 276         if (p == NULL) {
 277                 strlcpy(ebuf, pcap_strerror(errno), PCAP_ERRBUF_SIZE);
 278                 return (NULL);
 279         }
 280
 281         if (snaplen < 96)
 282                 /*
 283                  * NIT requires a snapshot length of at least 96.
 284                  */
 285                 snaplen = 96;
 286
 287         memset(p, 0, sizeof(*p));
 288         /*
 289          * Initially try a read/write open (to allow the inject
 290          * method to work).  If that fails due to permission
 291          * issues, fall back to read-only.  This allows a
 292          * non-root user to be granted specific access to pcap
 293          * capabilities via file permissions.
 294          *
 295          * XXX - we should have an API that has a flag that
 296          * controls whether to open read-only or read-write,
 297          * so that denial of permission to send (or inability
 298          * to send, if sending packets isn't supported on
 299          * the device in question) can be indicated at open
 300          * time.
 301          */
 302         p->fd = fd = open(dev, O_RDWR);
 303         if (fd < 0 && errno == EACCES)
 304                 p->fd = fd = open(dev, O_RDONLY);
 305         if (fd < 0) {
 306                 snprintf(ebuf, PCAP_ERRBUF_SIZE, "%s: %s", dev,
 307                     pcap_strerror(errno));
 308                 goto bad;
 309         }
 310
 311         /* arrange to get discrete messages from the STREAM and use NIT_BUF */
 312         if (ioctl(fd, I_SRDOPT, (char *)RMSGD) < 0) {
 313                 snprintf(ebuf, PCAP_ERRBUF_SIZE, "I_SRDOPT: %s",
 314                     pcap_strerror(errno));
 315                 goto bad;
 316         }
 317         if (ioctl(fd, I_PUSH, "nbuf") < 0) {
 318                 snprintf(ebuf, PCAP_ERRBUF_SIZE, "push nbuf: %s",
 319                     pcap_strerror(errno));
 320                 goto bad;
 321         }
 322         /* set the chunksize */
 323         si.ic_cmd = NIOCSCHUNK;
 324         si.ic_timout = INFTIM;
 325         si.ic_len = sizeof(chunksize);
 326         si.ic_dp = (char *)&chunksize;
 327         if (ioctl(fd, I_STR, (char *)&si) < 0) {
 328                 snprintf(ebuf, PCAP_ERRBUF_SIZE, "NIOCSCHUNK: %s",
 329                     pcap_strerror(errno));
 330                 goto bad;
 331         }
 332
 333         /* request the interface */
 334         strncpy(ifr.ifr_name, device, sizeof(ifr.ifr_name));
 335         ifr.ifr_name[sizeof(ifr.ifr_name) - 1] = '\0';
 336         si.ic_cmd = NIOCBIND;
 337         si.ic_len = sizeof(ifr);
 338         si.ic_dp = (char *)&ifr;
 339         if (ioctl(fd, I_STR, (char *)&si) < 0) {
 340                 snprintf(ebuf, PCAP_ERRBUF_SIZE, "NIOCBIND: %s: %s",
 341                         ifr.ifr_name, pcap_strerror(errno));
 342                 goto bad;
 343         }
 344
 345         /* set the snapshot length */
 346         si.ic_cmd = NIOCSSNAP;
 347         si.ic_len = sizeof(snaplen);
 348         si.ic_dp = (char *)&snaplen;
 349         if (ioctl(fd, I_STR, (char *)&si) < 0) {
 350                 snprintf(ebuf, PCAP_ERRBUF_SIZE, "NIOCSSNAP: %s",
 351                     pcap_strerror(errno));
 352                 goto bad;
 353         }
 354         p->snapshot = snaplen;
 355         if (nit_setflags(p->fd, promisc, to_ms, ebuf) < 0)
 356                 goto bad;
 357
 358         (void)ioctl(fd, I_FLUSH, (char *)FLUSHR);
 359         /*
 360          * NIT supports only ethernets.
 361          */
 362         p->linktype = DLT_EN10MB;
 363
 364         p->bufsize = BUFSPACE;
 365         p->buffer = (u_char *)malloc(p->bufsize);
 366         if (p->buffer == NULL) {
 367                 strlcpy(ebuf, pcap_strerror(errno), PCAP_ERRBUF_SIZE);
 368                 goto bad;
 369         }
 370
 371         /*
 372          * "p->fd" is an FD for a STREAMS device, so "select()" and
 373          * "poll()" should work on it.
 374          */
 375         p->selectable_fd = p->fd;
 376
 377         /*
 378          * This is (presumably) a real Ethernet capture; give it a
 379          * link-layer-type list with DLT_EN10MB and DLT_DOCSIS, so
 380          * that an application can let you choose it, in case you're
 381          * capturing DOCSIS traffic that a Cisco Cable Modem
 382          * Termination System is putting out onto an Ethernet (it
 383          * doesn't put an Ethernet header onto the wire, it puts raw
 384          * DOCSIS frames out on the wire inside the low-level
 385          * Ethernet framing).
 386          */
 387         p->dlt_list = (u_int *) malloc(sizeof(u_int) * 2);
 388         /*
 389          * If that fails, just leave the list empty.
 390          */
 391         if (p->dlt_list != NULL) {
 392                 p->dlt_list[0] = DLT_EN10MB;
 393                 p->dlt_list[1] = DLT_DOCSIS;
 394                 p->dlt_count = 2;
 395         }
 396
 397         p->read_op = pcap_read_snit;
 398         p->inject_op = pcap_inject_snit;
 399         p->setfilter_op = install_bpf_program;  /* no kernel filtering */
 400         p->setdirection_op = NULL;      /* Not implemented. */
 401         p->set_datalink_op = NULL;      /* can't change data link type */
 402         p->getnonblock_op = pcap_getnonblock_fd;
 403         p->setnonblock_op = pcap_setnonblock_fd;
 404         p->stats_op = pcap_stats_snit;
 405         p->close_op = pcap_close_common;
 406
 407         return (p);
 408  bad:
 409         if (fd >= 0)
 410                 close(fd);
 411         free(p);
 412         return (NULL);
 413 }
 414
 415 int
 416 pcap_platform_finddevs(pcap_if_t **alldevsp, char *errbuf)
 417 {
 418         return (0);
 419 }