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 /*
  88  * Private data for capturing on STREAMS NIT devices.
  89  */
  90 struct pcap_snit {
  91         struct pcap_stat stat;
  92 };
  93
  94 static int
  95 pcap_stats_snit(pcap_t *p, struct pcap_stat *ps)
  96 {
  97         struct pcap_snit *psn = p->private;
  98
  99         /*
 100          * "ps_recv" counts packets handed to the filter, not packets
 101          * that passed the filter.  As filtering is done in userland,
 102          * this does not include packets dropped because we ran out
 103          * of buffer space.
 104          *
 105          * "ps_drop" counts packets dropped inside the "/dev/nit"
 106          * device because of flow control requirements or resource
 107          * exhaustion; it doesn't count packets dropped by the
 108          * interface driver, or packets dropped upstream.  As filtering
 109          * is done in userland, it counts packets regardless of whether
 110          * they would've passed the filter.
 111          *
 112          * These statistics don't include packets not yet read from the
 113          * kernel by libpcap or packets not yet read from libpcap by the
 114          * application.
 115          */
 116         *ps = psn->stat;
 117         return (0);
 118 }
 119
 120 static int
 121 pcap_read_snit(pcap_t *p, int cnt, pcap_handler callback, u_char *user)
 122 {
 123         struct pcap_snit *psn = p->private;
 124         register int cc, n;
 125         register u_char *bp, *cp, *ep;
 126         register struct nit_bufhdr *hdrp;
 127         register struct nit_iftime *ntp;
 128         register struct nit_iflen *nlp;
 129         register struct nit_ifdrops *ndp;
 130         register int caplen;
 131
 132         cc = p->cc;
 133         if (cc == 0) {
 134                 cc = read(p->fd, (char *)p->buffer, p->bufsize);
 135                 if (cc < 0) {
 136                         if (errno == EWOULDBLOCK)
 137                                 return (0);
 138                         snprintf(p->errbuf, sizeof(p->errbuf), "pcap_read: %s",
 139                                 pcap_strerror(errno));
 140                         return (-1);
 141                 }
 142                 bp = p->buffer;
 143         } else
 144                 bp = p->bp;
 145
 146         /*
 147          * loop through each snapshot in the chunk
 148          */
 149         n = 0;
 150         ep = bp + cc;
 151         while (bp < ep) {
 152                 /*
 153                  * Has "pcap_breakloop()" been called?
 154                  * If so, return immediately - if we haven't read any
 155                  * packets, clear the flag and return -2 to indicate
 156                  * that we were told to break out of the loop, otherwise
 157                  * leave the flag set, so that the *next* call will break
 158                  * out of the loop without having read any packets, and
 159                  * return the number of packets we've processed so far.
 160                  */
 161                 if (p->break_loop) {
 162                         if (n == 0) {
 163                                 p->break_loop = 0;
 164                                 return (-2);
 165                         } else {
 166                                 p->bp = bp;
 167                                 p->cc = ep - bp;
 168                                 return (n);
 169                         }
 170                 }
 171
 172                 ++psn->stat.ps_recv;
 173                 cp = bp;
 174
 175                 /* get past NIT buffer  */
 176                 hdrp = (struct nit_bufhdr *)cp;
 177                 cp += sizeof(*hdrp);
 178
 179                 /* get past NIT timer   */
 180                 ntp = (struct nit_iftime *)cp;
 181                 cp += sizeof(*ntp);
 182
 183                 ndp = (struct nit_ifdrops *)cp;
 184                 psn->stat.ps_drop = ndp->nh_drops;
 185                 cp += sizeof *ndp;
 186
 187                 /* get past packet len  */
 188                 nlp = (struct nit_iflen *)cp;
 189                 cp += sizeof(*nlp);
 190
 191                 /* next snapshot        */
 192                 bp += hdrp->nhb_totlen;
 193
 194                 caplen = nlp->nh_pktlen;
 195                 if (caplen > p->snapshot)
 196                         caplen = p->snapshot;
 197
 198                 if (bpf_filter(p->fcode.bf_insns, cp, nlp->nh_pktlen, caplen)) {
 199                         struct pcap_pkthdr h;
 200                         h.ts = ntp->nh_timestamp;
 201                         h.len = nlp->nh_pktlen;
 202                         h.caplen = caplen;
 203                         (*callback)(user, &h, cp);
 204                         if (++n >= cnt && cnt > 0) {
 205                                 p->cc = ep - bp;
 206                                 p->bp = bp;
 207                                 return (n);
 208                         }
 209                 }
 210         }
 211         p->cc = 0;
 212         return (n);
 213 }
 214
 215 static int
 216 pcap_inject_snit(pcap_t *p, const void *buf, size_t size)
 217 {
 218         struct strbuf ctl, data;
 219
 220         /*
 221          * XXX - can we just do
 222          *
 223         ret = write(pd->f, buf, size);
 224          */
 225         ctl.len = sizeof(*sa);  /* XXX - what was this? */
 226         ctl.buf = (char *)sa;
 227         data.buf = buf;
 228         data.len = size;
 229         ret = putmsg(p->fd, &ctl, &data);
 230         if (ret == -1) {
 231                 snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "send: %s",
 232                     pcap_strerror(errno));
 233                 return (-1);
 234         }
 235         return (ret);
 236 }
 237
 238 static int
 239 nit_setflags(int fd, int promisc, int to_ms, char *ebuf)
 240 {
 241         bpf_u_int32 flags;
 242         struct strioctl si;
 243         struct timeval timeout;
 244
 245         si.ic_timout = INFTIM;
 246         if (to_ms != 0) {
 247                 timeout.tv_sec = to_ms / 1000;
 248                 timeout.tv_usec = (to_ms * 1000) % 1000000;
 249                 si.ic_cmd = NIOCSTIME;
 250                 si.ic_len = sizeof(timeout);
 251                 si.ic_dp = (char *)&timeout;
 252                 if (ioctl(fd, I_STR, (char *)&si) < 0) {
 253                         snprintf(ebuf, PCAP_ERRBUF_SIZE, "NIOCSTIME: %s",
 254                             pcap_strerror(errno));
 255                         return (-1);
 256                 }
 257         }
 258         flags = NI_TIMESTAMP | NI_LEN | NI_DROPS;
 259         if (promisc)
 260                 flags |= NI_PROMISC;
 261         si.ic_cmd = NIOCSFLAGS;
 262         si.ic_len = sizeof(flags);
 263         si.ic_dp = (char *)&flags;
 264         if (ioctl(fd, I_STR, (char *)&si) < 0) {
 265                 snprintf(ebuf, PCAP_ERRBUF_SIZE, "NIOCSFLAGS: %s",
 266                     pcap_strerror(errno));
 267                 return (-1);
 268         }
 269         return (0);
 270 }
 271
 272 static int
 273 pcap_activate_snit(pcap_t *p)
 274 {
 275         struct strioctl si;             /* struct for ioctl() */
 276         struct ifreq ifr;               /* interface request struct */
 277         int chunksize = CHUNKSIZE;
 278         int fd;
 279         static char dev[] = "/dev/nit";
 280
 281         if (p->opt.rfmon) {
 282                 /*
 283                  * No monitor mode on SunOS 4.x (no Wi-Fi devices on
 284                  * hardware supported by SunOS 4.x).
 285                  */
 286                 return (PCAP_ERROR_RFMON_NOTSUP);
 287         }
 288
 289         if (p->snapshot < 96)
 290                 /*
 291                  * NIT requires a snapshot length of at least 96.
 292                  */
 293                 p->snapshot = 96;
 294
 295         /*
 296          * Initially try a read/write open (to allow the inject
 297          * method to work).  If that fails due to permission
 298          * issues, fall back to read-only.  This allows a
 299          * non-root user to be granted specific access to pcap
 300          * capabilities via file permissions.
 301          *
 302          * XXX - we should have an API that has a flag that
 303          * controls whether to open read-only or read-write,
 304          * so that denial of permission to send (or inability
 305          * to send, if sending packets isn't supported on
 306          * the device in question) can be indicated at open
 307          * time.
 308          */
 309         p->fd = fd = open(dev, O_RDWR);
 310         if (fd < 0 && errno == EACCES)
 311                 p->fd = fd = open(dev, O_RDONLY);
 312         if (fd < 0) {
 313                 snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "%s: %s", dev,
 314                     pcap_strerror(errno));
 315                 goto bad;
 316         }
 317
 318         /* arrange to get discrete messages from the STREAM and use NIT_BUF */
 319         if (ioctl(fd, I_SRDOPT, (char *)RMSGD) < 0) {
 320                 snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "I_SRDOPT: %s",
 321                     pcap_strerror(errno));
 322                 goto bad;
 323         }
 324         if (ioctl(fd, I_PUSH, "nbuf") < 0) {
 325                 snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "push nbuf: %s",
 326                     pcap_strerror(errno));
 327                 goto bad;
 328         }
 329         /* set the chunksize */
 330         si.ic_cmd = NIOCSCHUNK;
 331         si.ic_timout = INFTIM;
 332         si.ic_len = sizeof(chunksize);
 333         si.ic_dp = (char *)&chunksize;
 334         if (ioctl(fd, I_STR, (char *)&si) < 0) {
 335                 snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "NIOCSCHUNK: %s",
 336                     pcap_strerror(errno));
 337                 goto bad;
 338         }
 339
 340         /* request the interface */
 341         strncpy(ifr.ifr_name, p->opt.source, sizeof(ifr.ifr_name));
 342         ifr.ifr_name[sizeof(ifr.ifr_name) - 1] = '\0';
 343         si.ic_cmd = NIOCBIND;
 344         si.ic_len = sizeof(ifr);
 345         si.ic_dp = (char *)&ifr;
 346         if (ioctl(fd, I_STR, (char *)&si) < 0) {
 347                 snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "NIOCBIND: %s: %s",
 348                         ifr.ifr_name, pcap_strerror(errno));
 349                 goto bad;
 350         }
 351
 352         /* set the snapshot length */
 353         si.ic_cmd = NIOCSSNAP;
 354         si.ic_len = sizeof(p->snapshot);
 355         si.ic_dp = (char *)&p->snapshot;
 356         if (ioctl(fd, I_STR, (char *)&si) < 0) {
 357                 snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "NIOCSSNAP: %s",
 358                     pcap_strerror(errno));
 359                 goto bad;
 360         }
 361         if (nit_setflags(p->fd, p->opt.promisc, p->opt.timeout, p->errbuf) < 0)
 362                 goto bad;
 363
 364         (void)ioctl(fd, I_FLUSH, (char *)FLUSHR);
 365         /*
 366          * NIT supports only ethernets.
 367          */
 368         p->linktype = DLT_EN10MB;
 369
 370         p->bufsize = BUFSPACE;
 371         p->buffer = (u_char *)malloc(p->bufsize);
 372         if (p->buffer == NULL) {
 373                 strlcpy(p->errbuf, pcap_strerror(errno), PCAP_ERRBUF_SIZE);
 374                 goto bad;
 375         }
 376
 377         /*
 378          * "p->fd" is an FD for a STREAMS device, so "select()" and
 379          * "poll()" should work on it.
 380          */
 381         p->selectable_fd = p->fd;
 382
 383         /*
 384          * This is (presumably) a real Ethernet capture; give it a
 385          * link-layer-type list with DLT_EN10MB and DLT_DOCSIS, so
 386          * that an application can let you choose it, in case you're
 387          * capturing DOCSIS traffic that a Cisco Cable Modem
 388          * Termination System is putting out onto an Ethernet (it
 389          * doesn't put an Ethernet header onto the wire, it puts raw
 390          * DOCSIS frames out on the wire inside the low-level
 391          * Ethernet framing).
 392          */
 393         p->dlt_list = (u_int *) malloc(sizeof(u_int) * 2);
 394         /*
 395          * If that fails, just leave the list empty.
 396          */
 397         if (p->dlt_list != NULL) {
 398                 p->dlt_list[0] = DLT_EN10MB;
 399                 p->dlt_list[1] = DLT_DOCSIS;
 400                 p->dlt_count = 2;
 401         }
 402
 403         p->read_op = pcap_read_snit;
 404         p->inject_op = pcap_inject_snit;
 405         p->setfilter_op = install_bpf_program;  /* no kernel filtering */
 406         p->setdirection_op = NULL;      /* Not implemented. */
 407         p->set_datalink_op = NULL;      /* can't change data link type */
 408         p->getnonblock_op = pcap_getnonblock_fd;
 409         p->setnonblock_op = pcap_setnonblock_fd;
 410         p->stats_op = pcap_stats_snit;
 411
 412         return (0);
 413  bad:
 414         pcap_cleanup_live_common(p);
 415         return (PCAP_ERROR);
 416 }
 417
 418 pcap_t *
 419 pcap_create_interface(const char *device, char *ebuf)
 420 {
 421         pcap_t *p;
 422
 423         p = pcap_create_common(device, ebuf, sizeof (struct pcap_snit));
 424         if (p == NULL)
 425                 return (NULL);
 426
 427         p->activate_op = pcap_activate_snit;
 428         return (p);
 429 }
 430
 431 int
 432 pcap_platform_finddevs(pcap_if_t **alldevsp, char *errbuf)
 433 {
 434         return (0);
 435 }