external/bsd/libpcap/dist/pcap-snoop.c

   1 /*      $NetBSD: pcap-snoop.c,v 1.3 2015/03/31 21:39:42 christos Exp $  */
   2
   3 /*
   4  * Copyright (c) 1993, 1994, 1995, 1996, 1997
   5  *      The Regents of the University of California.  All rights reserved.
   6  *
   7  * Redistribution and use in source and binary forms, with or without
   8  * modification, are permitted provided that: (1) source code distributions
   9  * retain the above copyright notice and this paragraph in its entirety, (2)
  10  * distributions including binary code include the above copyright notice and
  11  * this paragraph in its entirety in the documentation or other materials
  12  * provided with the distribution, and (3) all advertising materials mentioning
  13  * features or use of this software display the following acknowledgement:
  14  * ``This product includes software developed by the University of California,
  15  * Lawrence Berkeley Laboratory and its contributors.'' Neither the name of
  16  * the University nor the names of its contributors may be used to endorse
  17  * or promote products derived from this software without specific prior
  18  * written permission.
  19  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED
  20  * WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
  21  * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
  22  */
  23
  24 #include <sys/cdefs.h>
  25 __RCSID("$NetBSD: pcap-snoop.c,v 1.3 2015/03/31 21:39:42 christos Exp $");
  26
  27 #ifdef HAVE_CONFIG_H
  28 #include "config.h"
  29 #endif
  30
  31 #include <sys/param.h>
  32 #include <sys/file.h>
  33 #include <sys/ioctl.h>
  34 #include <sys/socket.h>
  35 #include <sys/time.h>
  36
  37 #include <net/raw.h>
  38 #include <net/if.h>
  39
  40 #include <netinet/in.h>
  41 #include <netinet/in_systm.h>
  42 #include <netinet/ip.h>
  43 #include <netinet/if_ether.h>
  44 #include <netinet/ip_var.h>
  45 #include <netinet/udp.h>
  46 #include <netinet/udp_var.h>
  47 #include <netinet/tcp.h>
  48 #include <netinet/tcpip.h>
  49
  50 #include <errno.h>
  51 #include <stdio.h>
  52 #include <stdlib.h>
  53 #include <string.h>
  54 #include <unistd.h>
  55
  56 #include "pcap-int.h"
  57
  58 #ifdef HAVE_OS_PROTO_H
  59 #include "os-proto.h"
  60 #endif
  61
  62 /*
  63  * Private data for capturing on snoop devices.
  64  */
  65 struct pcap_snoop {
  66         struct pcap_stat stat;
  67 };
  68
  69 static int
  70 pcap_read_snoop(pcap_t *p, int cnt, pcap_handler callback, u_char *user)
  71 {
  72         struct pcap_snoop *psn = p->priv;
  73         int cc;
  74         register struct snoopheader *sh;
  75         register u_int datalen;
  76         register u_int caplen;
  77         register u_char *cp;
  78
  79 again:
  80         /*
  81          * Has "pcap_breakloop()" been called?
  82          */
  83         if (p->break_loop) {
  84                 /*
  85                  * Yes - clear the flag that indicates that it
  86                  * has, and return -2 to indicate that we were
  87                  * told to break out of the loop.
  88                  */
  89                 p->break_loop = 0;
  90                 return (-2);
  91         }
  92         cc = read(p->fd, (char *)p->buffer, p->bufsize);
  93         if (cc < 0) {
  94                 /* Don't choke when we get ptraced */
  95                 switch (errno) {
  96
  97                 case EINTR:
  98                         goto again;
  99
 100                 case EWOULDBLOCK:
 101                         return (0);                     /* XXX */
 102                 }
 103                 snprintf(p->errbuf, sizeof(p->errbuf),
 104                     "read: %s", pcap_strerror(errno));
 105                 return (-1);
 106         }
 107         sh = (struct snoopheader *)p->buffer;
 108         datalen = sh->snoop_packetlen;
 109
 110         /*
 111          * XXX - Sigh, snoop_packetlen is a 16 bit quantity.  If we
 112          * got a short length, but read a full sized snoop pakcet,
 113          * assume we overflowed and add back the 64K...
 114          */
 115         if (cc == (p->snapshot + sizeof(struct snoopheader)) &&
 116             (datalen < p->snapshot))
 117                 datalen += (64 * 1024);
 118
 119         caplen = (datalen < p->snapshot) ? datalen : p->snapshot;
 120         cp = (u_char *)(sh + 1) + p->offset;            /* XXX */
 121
 122         /*
 123          * XXX unfortunately snoop loopback isn't exactly like
 124          * BSD's.  The address family is encoded in the first 2
 125          * bytes rather than the first 4 bytes!  Luckily the last
 126          * two snoop loopback bytes are zeroed.
 127          */
 128         if (p->linktype == DLT_NULL && *((short *)(cp + 2)) == 0) {
 129                 u_int *uip = (u_int *)cp;
 130                 *uip >>= 16;
 131         }
 132
 133         if (p->fcode.bf_insns == NULL ||
 134             bpf_filter(p->fcode.bf_insns, cp, datalen, caplen)) {
 135                 struct pcap_pkthdr h;
 136                 ++psn->stat.ps_recv;
 137                 h.ts.tv_sec = sh->snoop_timestamp.tv_sec;
 138                 h.ts.tv_usec = sh->snoop_timestamp.tv_usec;
 139                 h.len = datalen;
 140                 h.caplen = caplen;
 141                 (*callback)(user, &h, cp);
 142                 return (1);
 143         }
 144         return (0);
 145 }
 146
 147 static int
 148 pcap_inject_snoop(pcap_t *p, const void *buf, size_t size)
 149 {
 150         int ret;
 151
 152         /*
 153          * XXX - libnet overwrites the source address with what I
 154          * presume is the interface's address; is that required?
 155          */
 156         ret = write(p->fd, buf, size);
 157         if (ret == -1) {
 158                 snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "send: %s",
 159                     pcap_strerror(errno));
 160                 return (-1);
 161         }
 162         return (ret);
 163 }
 164
 165 static int
 166 pcap_stats_snoop(pcap_t *p, struct pcap_stat *ps)
 167 {
 168         struct pcap_snoop *psn = p->priv;
 169         register struct rawstats *rs;
 170         struct rawstats rawstats;
 171
 172         rs = &rawstats;
 173         memset(rs, 0, sizeof(*rs));
 174         if (ioctl(p->fd, SIOCRAWSTATS, (char *)rs) < 0) {
 175                 snprintf(p->errbuf, sizeof(p->errbuf),
 176                     "SIOCRAWSTATS: %s", pcap_strerror(errno));
 177                 return (-1);
 178         }
 179
 180         /*
 181          * "ifdrops" are those dropped by the network interface
 182          * due to resource shortages or hardware errors.
 183          *
 184          * "sbdrops" are those dropped due to socket buffer limits.
 185          *
 186          * As filter is done in userland, "sbdrops" counts packets
 187          * regardless of whether they would've passed the filter.
 188          *
 189          * XXX - does this count *all* Snoop or Drain sockets,
 190          * rather than just this socket?  If not, why does it have
 191          * both Snoop and Drain statistics?
 192          */
 193         psn->stat.ps_drop =
 194             rs->rs_snoop.ss_ifdrops + rs->rs_snoop.ss_sbdrops +
 195             rs->rs_drain.ds_ifdrops + rs->rs_drain.ds_sbdrops;
 196
 197         /*
 198          * "ps_recv" counts only packets that passed the filter.
 199          * As filtering is done in userland, this does not include
 200          * packets dropped because we ran out of buffer space.
 201          */
 202         *ps = psn->stat;
 203         return (0);
 204 }
 205
 206 /* XXX can't disable promiscuous */
 207 static int
 208 pcap_activate_snoop(pcap_t *p)
 209 {
 210         int fd;
 211         struct sockaddr_raw sr;
 212         struct snoopfilter sf;
 213         u_int v;
 214         int ll_hdrlen;
 215         int snooplen;
 216         struct ifreq ifr;
 217
 218         fd = socket(PF_RAW, SOCK_RAW, RAWPROTO_SNOOP);
 219         if (fd < 0) {
 220                 snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "snoop socket: %s",
 221                     pcap_strerror(errno));
 222                 goto bad;
 223         }
 224         p->fd = fd;
 225         memset(&sr, 0, sizeof(sr));
 226         sr.sr_family = AF_RAW;
 227         (void)strncpy(sr.sr_ifname, p->opt.source, sizeof(sr.sr_ifname));
 228         if (bind(fd, (struct sockaddr *)&sr, sizeof(sr))) {
 229                 snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "snoop bind: %s",
 230                     pcap_strerror(errno));
 231                 goto bad;
 232         }
 233         memset(&sf, 0, sizeof(sf));
 234         if (ioctl(fd, SIOCADDSNOOP, &sf) < 0) {
 235                 snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "SIOCADDSNOOP: %s",
 236                     pcap_strerror(errno));
 237                 goto bad;
 238         }
 239         if (p->opt.buffer_size != 0)
 240                 v = p->opt.buffer_size;
 241         else
 242                 v = 64 * 1024;  /* default to 64K buffer size */
 243         (void)setsockopt(fd, SOL_SOCKET, SO_RCVBUF, (char *)&v, sizeof(v));
 244         /*
 245          * XXX hack - map device name to link layer type
 246          */
 247         if (strncmp("et", p->opt.source, 2) == 0 ||     /* Challenge 10 Mbit */
 248             strncmp("ec", p->opt.source, 2) == 0 ||     /* Indigo/Indy 10 Mbit,
 249                                                            O2 10/100 */
 250             strncmp("ef", p->opt.source, 2) == 0 ||     /* O200/2000 10/100 Mbit */
 251             strncmp("eg", p->opt.source, 2) == 0 ||     /* Octane/O2xxx/O3xxx Gigabit */
 252             strncmp("gfe", p->opt.source, 3) == 0 ||    /* GIO 100 Mbit */
 253             strncmp("fxp", p->opt.source, 3) == 0 ||    /* Challenge VME Enet */
 254             strncmp("ep", p->opt.source, 2) == 0 ||     /* Challenge 8x10 Mbit EPLEX */
 255             strncmp("vfe", p->opt.source, 3) == 0 ||    /* Challenge VME 100Mbit */
 256             strncmp("fa", p->opt.source, 2) == 0 ||
 257             strncmp("qaa", p->opt.source, 3) == 0 ||
 258             strncmp("cip", p->opt.source, 3) == 0 ||
 259             strncmp("el", p->opt.source, 2) == 0) {
 260                 p->linktype = DLT_EN10MB;
 261                 p->offset = RAW_HDRPAD(sizeof(struct ether_header));
 262                 ll_hdrlen = sizeof(struct ether_header);
 263                 /*
 264                  * This is (presumably) a real Ethernet capture; give it a
 265                  * link-layer-type list with DLT_EN10MB and DLT_DOCSIS, so
 266                  * that an application can let you choose it, in case you're
 267                  * capturing DOCSIS traffic that a Cisco Cable Modem
 268                  * Termination System is putting out onto an Ethernet (it
 269                  * doesn't put an Ethernet header onto the wire, it puts raw
 270                  * DOCSIS frames out on the wire inside the low-level
 271                  * Ethernet framing).
 272                  *
 273                  * XXX - are there any sorts of "fake Ethernet" that have
 274                  * Ethernet link-layer headers but that *shouldn't offer
 275                  * DLT_DOCSIS as a Cisco CMTS won't put traffic onto it
 276                  * or get traffic bridged onto it?  "el" is for ATM LANE
 277                  * Ethernet devices, so that might be the case for them;
 278                  * the same applies for "qaa" classical IP devices.  If
 279                  * "fa" devices are for FORE SPANS, that'd apply to them
 280                  * as well; what are "cip" devices - some other ATM
 281                  * Classical IP devices?
 282                  */
 283                 p->dlt_list = (u_int *) malloc(sizeof(u_int) * 2);
 284                 /*
 285                  * If that fails, just leave the list empty.
 286                  */
 287                 if (p->dlt_list != NULL) {
 288                         p->dlt_list[0] = DLT_EN10MB;
 289                         p->dlt_list[1] = DLT_DOCSIS;
 290                         p->dlt_count = 2;
 291                 }
 292         } else if (strncmp("ipg", p->opt.source, 3) == 0 ||
 293                    strncmp("rns", p->opt.source, 3) == 0 ||     /* O2/200/2000 FDDI */
 294                    strncmp("xpi", p->opt.source, 3) == 0) {
 295                 p->linktype = DLT_FDDI;
 296                 p->offset = 3;                          /* XXX yeah? */
 297                 ll_hdrlen = 13;
 298         } else if (strncmp("ppp", p->opt.source, 3) == 0) {
 299                 p->linktype = DLT_RAW;
 300                 ll_hdrlen = 0;  /* DLT_RAW meaning "no PPP header, just the IP packet"? */
 301         } else if (strncmp("qfa", p->opt.source, 3) == 0) {
 302                 p->linktype = DLT_IP_OVER_FC;
 303                 ll_hdrlen = 24;
 304         } else if (strncmp("pl", p->opt.source, 2) == 0) {
 305                 p->linktype = DLT_RAW;
 306                 ll_hdrlen = 0;  /* Cray UNICOS/mp pseudo link */
 307         } else if (strncmp("lo", p->opt.source, 2) == 0) {
 308                 p->linktype = DLT_NULL;
 309                 ll_hdrlen = 4;
 310         } else {
 311                 snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
 312                     "snoop: unknown physical layer type");
 313                 goto bad;
 314         }
 315
 316         if (p->opt.rfmon) {
 317                 /*
 318                  * No monitor mode on Irix (no Wi-Fi devices on
 319                  * hardware supported by Irix).
 320                  */
 321                 return (PCAP_ERROR_RFMON_NOTSUP);
 322         }
 323
 324 #ifdef SIOCGIFMTU
 325         /*
 326          * XXX - IRIX appears to give you an error if you try to set the
 327          * capture length to be greater than the MTU, so let's try to get
 328          * the MTU first and, if that succeeds, trim the snap length
 329          * to be no greater than the MTU.
 330          */
 331         (void)strncpy(ifr.ifr_name, p->opt.source, sizeof(ifr.ifr_name));
 332         if (ioctl(fd, SIOCGIFMTU, (char *)&ifr) < 0) {
 333                 snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "SIOCGIFMTU: %s",
 334                     pcap_strerror(errno));
 335                 goto bad;
 336         }
 337         /*
 338          * OK, we got it.
 339          *
 340          * XXX - some versions of IRIX 6.5 define "ifr_mtu" and have an
 341          * "ifru_metric" member of the "ifr_ifru" union in an "ifreq"
 342          * structure, others don't.
 343          *
 344          * I've no idea what's going on, so, if "ifr_mtu" isn't defined,
 345          * we define it as "ifr_metric", as using that field appears to
 346          * work on the versions that lack "ifr_mtu" (and, on those that
 347          * don't lack it, "ifru_metric" and "ifru_mtu" are both "int"
 348          * members of the "ifr_ifru" union, which suggests that they
 349          * may be interchangeable in this case).
 350          */
 351 #ifndef ifr_mtu
 352 #define ifr_mtu ifr_metric
 353 #endif
 354         if (p->snapshot > ifr.ifr_mtu + ll_hdrlen)
 355                 p->snapshot = ifr.ifr_mtu + ll_hdrlen;
 356 #endif
 357
 358         /*
 359          * The argument to SIOCSNOOPLEN is the number of link-layer
 360          * payload bytes to capture - it doesn't count link-layer
 361          * header bytes.
 362          */
 363         snooplen = p->snapshot - ll_hdrlen;
 364         if (snooplen < 0)
 365                 snooplen = 0;
 366         if (ioctl(fd, SIOCSNOOPLEN, &snooplen) < 0) {
 367                 snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "SIOCSNOOPLEN: %s",
 368                     pcap_strerror(errno));
 369                 goto bad;
 370         }
 371         v = 1;
 372         if (ioctl(fd, SIOCSNOOPING, &v) < 0) {
 373                 snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "SIOCSNOOPING: %s",
 374                     pcap_strerror(errno));
 375                 goto bad;
 376         }
 377
 378         p->bufsize = 4096;                              /* XXX */
 379         p->buffer = (u_char *)malloc(p->bufsize);
 380         if (p->buffer == NULL) {
 381                 snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "malloc: %s",
 382                     pcap_strerror(errno));
 383                 goto bad;
 384         }
 385
 386         /*
 387          * "p->fd" is a socket, so "select()" should work on it.
 388          */
 389         p->selectable_fd = p->fd;
 390
 391         p->read_op = pcap_read_snoop;
 392         p->inject_op = pcap_inject_snoop;
 393         p->setfilter_op = install_bpf_program;  /* no kernel filtering */
 394         p->setdirection_op = NULL;      /* Not implemented. */
 395         p->set_datalink_op = NULL;      /* can't change data link type */
 396         p->getnonblock_op = pcap_getnonblock_fd;
 397         p->setnonblock_op = pcap_setnonblock_fd;
 398         p->stats_op = pcap_stats_snoop;
 399
 400         return (0);
 401  bad:
 402         pcap_cleanup_live_common(p);
 403         return (PCAP_ERROR);
 404 }
 405
 406 pcap_t *
 407 pcap_create_interface(const char *device, char *ebuf)
 408 {
 409         pcap_t *p;
 410
 411         p = pcap_create_common(device, ebuf, sizeof (struct pcap_snoop));
 412         if (p == NULL)
 413                 return (NULL);
 414
 415         p->activate_op = pcap_activate_snoop;
 416         return (p);
 417 }
 418
 419 int
 420 pcap_platform_finddevs(pcap_if_t **alldevsp, char *errbuf)
 421 {
 422         return (0);
 423 }