dist/libpcap/pcap-snoop.c

   1 /*
   2  * Copyright (c) 1993, 1994, 1995, 1996, 1997
   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 #ifndef lint
  22 static const char rcsid[] _U_ =
  23     "@(#) $Header: /pub/NetBSD/misc/repositories/cvsroot/src/dist/libpcap/pcap-snoop.c,v 1.1.1.1 2006/02/27 15:45:49 drochner Exp $ (LBL)";
  24 #endif
  25
  26 #ifdef HAVE_CONFIG_H
  27 #include "config.h"
  28 #endif
  29
  30 #include <sys/param.h>
  31 #include <sys/file.h>
  32 #include <sys/ioctl.h>
  33 #include <sys/socket.h>
  34 #include <sys/time.h>
  35
  36 #include <net/raw.h>
  37 #include <net/if.h>
  38
  39 #include <netinet/in.h>
  40 #include <netinet/in_systm.h>
  41 #include <netinet/ip.h>
  42 #include <netinet/if_ether.h>
  43 #include <netinet/ip_var.h>
  44 #include <netinet/udp.h>
  45 #include <netinet/udp_var.h>
  46 #include <netinet/tcp.h>
  47 #include <netinet/tcpip.h>
  48
  49 #include <errno.h>
  50 #include <stdio.h>
  51 #include <stdlib.h>
  52 #include <string.h>
  53 #include <unistd.h>
  54
  55 #include "pcap-int.h"
  56
  57 #ifdef HAVE_OS_PROTO_H
  58 #include "os-proto.h"
  59 #endif
  60
  61 static int
  62 pcap_read_snoop(pcap_t *p, int cnt, pcap_handler callback, u_char *user)
  63 {
  64         int cc;
  65         register struct snoopheader *sh;
  66         register u_int datalen;
  67         register u_int caplen;
  68         register u_char *cp;
  69
  70 again:
  71         /*
  72          * Has "pcap_breakloop()" been called?
  73          */
  74         if (p->break_loop) {
  75                 /*
  76                  * Yes - clear the flag that indicates that it
  77                  * has, and return -2 to indicate that we were
  78                  * told to break out of the loop.
  79                  */
  80                 p->break_loop = 0;
  81                 return (-2);
  82         }
  83         cc = read(p->fd, (char *)p->buffer, p->bufsize);
  84         if (cc < 0) {
  85                 /* Don't choke when we get ptraced */
  86                 switch (errno) {
  87
  88                 case EINTR:
  89                         goto again;
  90
  91                 case EWOULDBLOCK:
  92                         return (0);                     /* XXX */
  93                 }
  94                 snprintf(p->errbuf, sizeof(p->errbuf),
  95                     "read: %s", pcap_strerror(errno));
  96                 return (-1);
  97         }
  98         sh = (struct snoopheader *)p->buffer;
  99         datalen = sh->snoop_packetlen;
 100
 101         /*
 102          * XXX - Sigh, snoop_packetlen is a 16 bit quantity.  If we
 103          * got a short length, but read a full sized snoop pakcet,
 104          * assume we overflowed and add back the 64K...
 105          */
 106         if (cc == (p->snapshot + sizeof(struct snoopheader)) &&
 107             (datalen < p->snapshot))
 108                 datalen += (64 * 1024);
 109
 110         caplen = (datalen < p->snapshot) ? datalen : p->snapshot;
 111         cp = (u_char *)(sh + 1) + p->offset;            /* XXX */
 112
 113         /*
 114          * XXX unfortunately snoop loopback isn't exactly like
 115          * BSD's.  The address family is encoded in the first 2
 116          * bytes rather than the first 4 bytes!  Luckily the last
 117          * two snoop loopback bytes are zeroed.
 118          */
 119         if (p->linktype == DLT_NULL && *((short *)(cp + 2)) == 0) {
 120                 u_int *uip = (u_int *)cp;
 121                 *uip >>= 16;
 122         }
 123
 124         if (p->fcode.bf_insns == NULL ||
 125             bpf_filter(p->fcode.bf_insns, cp, datalen, caplen)) {
 126                 struct pcap_pkthdr h;
 127                 ++p->md.stat.ps_recv;
 128                 h.ts.tv_sec = sh->snoop_timestamp.tv_sec;
 129                 h.ts.tv_usec = sh->snoop_timestamp.tv_usec;
 130                 h.len = datalen;
 131                 h.caplen = caplen;
 132                 (*callback)(user, &h, cp);
 133                 return (1);
 134         }
 135         return (0);
 136 }
 137
 138 static int
 139 pcap_inject_snoop(pcap_t *p, const void *buf, size_t size)
 140 {
 141         int ret;
 142
 143         /*
 144          * XXX - libnet overwrites the source address with what I
 145          * presume is the interface's address; is that required?
 146          */
 147         ret = write(p->fd, buf, size);
 148         if (ret == -1) {
 149                 snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "send: %s",
 150                     pcap_strerror(errno));
 151                 return (-1);
 152         }
 153         return (ret);
 154 }
 155
 156 static int
 157 pcap_stats_snoop(pcap_t *p, struct pcap_stat *ps)
 158 {
 159         register struct rawstats *rs;
 160         struct rawstats rawstats;
 161
 162         rs = &rawstats;
 163         memset(rs, 0, sizeof(*rs));
 164         if (ioctl(p->fd, SIOCRAWSTATS, (char *)rs) < 0) {
 165                 snprintf(p->errbuf, sizeof(p->errbuf),
 166                     "SIOCRAWSTATS: %s", pcap_strerror(errno));
 167                 return (-1);
 168         }
 169
 170         /*
 171          * "ifdrops" are those dropped by the network interface
 172          * due to resource shortages or hardware errors.
 173          *
 174          * "sbdrops" are those dropped due to socket buffer limits.
 175          *
 176          * As filter is done in userland, "sbdrops" counts packets
 177          * regardless of whether they would've passed the filter.
 178          *
 179          * XXX - does this count *all* Snoop or Drain sockets,
 180          * rather than just this socket?  If not, why does it have
 181          * both Snoop and Drain statistics?
 182          */
 183         p->md.stat.ps_drop =
 184             rs->rs_snoop.ss_ifdrops + rs->rs_snoop.ss_sbdrops +
 185             rs->rs_drain.ds_ifdrops + rs->rs_drain.ds_sbdrops;
 186
 187         /*
 188          * "ps_recv" counts only packets that passed the filter.
 189          * As filtering is done in userland, this does not include
 190          * packets dropped because we ran out of buffer space.
 191          */
 192         *ps = p->md.stat;
 193         return (0);
 194 }
 195
 196 /* XXX can't disable promiscuous */
 197 pcap_t *
 198 pcap_open_live(const char *device, int snaplen, int promisc, int to_ms,
 199     char *ebuf)
 200 {
 201         int fd;
 202         struct sockaddr_raw sr;
 203         struct snoopfilter sf;
 204         u_int v;
 205         int ll_hdrlen;
 206         int snooplen;
 207         pcap_t *p;
 208         struct ifreq ifr;
 209
 210         p = (pcap_t *)malloc(sizeof(*p));
 211         if (p == NULL) {
 212                 snprintf(ebuf, PCAP_ERRBUF_SIZE, "malloc: %s",
 213                     pcap_strerror(errno));
 214                 return (NULL);
 215         }
 216         memset(p, 0, sizeof(*p));
 217         fd = socket(PF_RAW, SOCK_RAW, RAWPROTO_SNOOP);
 218         if (fd < 0) {
 219                 snprintf(ebuf, PCAP_ERRBUF_SIZE, "snoop socket: %s",
 220                     pcap_strerror(errno));
 221                 goto bad;
 222         }
 223         p->fd = fd;
 224         memset(&sr, 0, sizeof(sr));
 225         sr.sr_family = AF_RAW;
 226         (void)strncpy(sr.sr_ifname, device, sizeof(sr.sr_ifname));
 227         if (bind(fd, (struct sockaddr *)&sr, sizeof(sr))) {
 228                 snprintf(ebuf, PCAP_ERRBUF_SIZE, "snoop bind: %s",
 229                     pcap_strerror(errno));
 230                 goto bad;
 231         }
 232         memset(&sf, 0, sizeof(sf));
 233         if (ioctl(fd, SIOCADDSNOOP, &sf) < 0) {
 234                 snprintf(ebuf, PCAP_ERRBUF_SIZE, "SIOCADDSNOOP: %s",
 235                     pcap_strerror(errno));
 236                 goto bad;
 237         }
 238         v = 64 * 1024;
 239         (void)setsockopt(fd, SOL_SOCKET, SO_RCVBUF, (char *)&v, sizeof(v));
 240         /*
 241          * XXX hack - map device name to link layer type
 242          */
 243         if (strncmp("et", device, 2) == 0 ||    /* Challenge 10 Mbit */
 244             strncmp("ec", device, 2) == 0 ||    /* Indigo/Indy 10 Mbit,
 245                                                    O2 10/100 */
 246             strncmp("ef", device, 2) == 0 ||    /* O200/2000 10/100 Mbit */
 247             strncmp("eg", device, 2) == 0 ||    /* Octane/O2xxx/O3xxx Gigabit */
 248             strncmp("gfe", device, 3) == 0 ||   /* GIO 100 Mbit */
 249             strncmp("fxp", device, 3) == 0 ||   /* Challenge VME Enet */
 250             strncmp("ep", device, 2) == 0 ||    /* Challenge 8x10 Mbit EPLEX */
 251             strncmp("vfe", device, 3) == 0 ||   /* Challenge VME 100Mbit */
 252             strncmp("fa", device, 2) == 0 ||
 253             strncmp("qaa", device, 3) == 0 ||
 254             strncmp("cip", device, 3) == 0 ||
 255             strncmp("el", device, 2) == 0) {
 256                 p->linktype = DLT_EN10MB;
 257                 p->offset = RAW_HDRPAD(sizeof(struct ether_header));
 258                 ll_hdrlen = sizeof(struct ether_header);
 259                 /*
 260                  * This is (presumably) a real Ethernet capture; give it a
 261                  * link-layer-type list with DLT_EN10MB and DLT_DOCSIS, so
 262                  * that an application can let you choose it, in case you're
 263                  * capturing DOCSIS traffic that a Cisco Cable Modem
 264                  * Termination System is putting out onto an Ethernet (it
 265                  * doesn't put an Ethernet header onto the wire, it puts raw
 266                  * DOCSIS frames out on the wire inside the low-level
 267                  * Ethernet framing).
 268                  *
 269                  * XXX - are there any sorts of "fake Ethernet" that have
 270                  * Ethernet link-layer headers but that *shouldn't offer
 271                  * DLT_DOCSIS as a Cisco CMTS won't put traffic onto it
 272                  * or get traffic bridged onto it?  "el" is for ATM LANE
 273                  * Ethernet devices, so that might be the case for them;
 274                  * the same applies for "qaa" classical IP devices.  If
 275                  * "fa" devices are for FORE SPANS, that'd apply to them
 276                  * as well; what are "cip" devices - some other ATM
 277                  * Classical IP devices?
 278                  */
 279                 p->dlt_list = (u_int *) malloc(sizeof(u_int) * 2);
 280                 /*
 281                  * If that fails, just leave the list empty.
 282                  */
 283                 if (p->dlt_list != NULL) {
 284                         p->dlt_list[0] = DLT_EN10MB;
 285                         p->dlt_list[1] = DLT_DOCSIS;
 286                         p->dlt_count = 2;
 287                 }
 288         } else if (strncmp("ipg", device, 3) == 0 ||
 289                    strncmp("rns", device, 3) == 0 ||    /* O2/200/2000 FDDI */
 290                    strncmp("xpi", device, 3) == 0) {
 291                 p->linktype = DLT_FDDI;
 292                 p->offset = 3;                          /* XXX yeah? */
 293                 ll_hdrlen = 13;
 294         } else if (strncmp("ppp", device, 3) == 0) {
 295                 p->linktype = DLT_RAW;
 296                 ll_hdrlen = 0;  /* DLT_RAW meaning "no PPP header, just the IP packet"? */
 297         } else if (strncmp("qfa", device, 3) == 0) {
 298                 p->linktype = DLT_IP_OVER_FC;
 299                 ll_hdrlen = 24;
 300         } else if (strncmp("pl", device, 2) == 0) {
 301                 p->linktype = DLT_RAW;
 302                 ll_hdrlen = 0;  /* Cray UNICOS/mp pseudo link */
 303         } else if (strncmp("lo", device, 2) == 0) {
 304                 p->linktype = DLT_NULL;
 305                 ll_hdrlen = 4;
 306         } else {
 307                 snprintf(ebuf, PCAP_ERRBUF_SIZE,
 308                     "snoop: unknown physical layer type");
 309                 goto bad;
 310         }
 311 #ifdef SIOCGIFMTU
 312         /*
 313          * XXX - IRIX appears to give you an error if you try to set the
 314          * capture length to be greater than the MTU, so let's try to get
 315          * the MTU first and, if that succeeds, trim the snap length
 316          * to be no greater than the MTU.
 317          */
 318         (void)strncpy(ifr.ifr_name, device, sizeof(ifr.ifr_name));
 319         if (ioctl(fd, SIOCGIFMTU, (char *)&ifr) < 0) {
 320                 snprintf(ebuf, PCAP_ERRBUF_SIZE, "SIOCGIFMTU: %s",
 321                     pcap_strerror(errno));
 322                 goto bad;
 323         }
 324         /*
 325          * OK, we got it.
 326          *
 327          * XXX - some versions of IRIX 6.5 define "ifr_mtu" and have an
 328          * "ifru_metric" member of the "ifr_ifru" union in an "ifreq"
 329          * structure, others don't.
 330          *
 331          * I've no idea what's going on, so, if "ifr_mtu" isn't defined,
 332          * we define it as "ifr_metric", as using that field appears to
 333          * work on the versions that lack "ifr_mtu" (and, on those that
 334          * don't lack it, "ifru_metric" and "ifru_mtu" are both "int"
 335          * members of the "ifr_ifru" union, which suggests that they
 336          * may be interchangeable in this case).
 337          */
 338 #ifndef ifr_mtu
 339 #define ifr_mtu ifr_metric
 340 #endif
 341         if (snaplen > ifr.ifr_mtu + ll_hdrlen)
 342                 snaplen = ifr.ifr_mtu + ll_hdrlen;
 343 #endif
 344
 345         /*
 346          * The argument to SIOCSNOOPLEN is the number of link-layer
 347          * payload bytes to capture - it doesn't count link-layer
 348          * header bytes.
 349          */
 350         snooplen = snaplen - ll_hdrlen;
 351         if (snooplen < 0)
 352                 snooplen = 0;
 353         if (ioctl(fd, SIOCSNOOPLEN, &snooplen) < 0) {
 354                 snprintf(ebuf, PCAP_ERRBUF_SIZE, "SIOCSNOOPLEN: %s",
 355                     pcap_strerror(errno));
 356                 goto bad;
 357         }
 358         p->snapshot = snaplen;
 359         v = 1;
 360         if (ioctl(fd, SIOCSNOOPING, &v) < 0) {
 361                 snprintf(ebuf, PCAP_ERRBUF_SIZE, "SIOCSNOOPING: %s",
 362                     pcap_strerror(errno));
 363                 goto bad;
 364         }
 365
 366         p->bufsize = 4096;                              /* XXX */
 367         p->buffer = (u_char *)malloc(p->bufsize);
 368         if (p->buffer == NULL) {
 369                 snprintf(ebuf, PCAP_ERRBUF_SIZE, "malloc: %s",
 370                     pcap_strerror(errno));
 371                 goto bad;
 372         }
 373
 374         /*
 375          * "p->fd" is a socket, so "select()" should work on it.
 376          */
 377         p->selectable_fd = p->fd;
 378
 379         p->read_op = pcap_read_snoop;
 380         p->inject_op = pcap_inject_snoop;
 381         p->setfilter_op = install_bpf_program;  /* no kernel filtering */
 382         p->setdirection_op = NULL;      /* Not implemented. */
 383         p->set_datalink_op = NULL;      /* can't change data link type */
 384         p->getnonblock_op = pcap_getnonblock_fd;
 385         p->setnonblock_op = pcap_setnonblock_fd;
 386         p->stats_op = pcap_stats_snoop;
 387         p->close_op = pcap_close_common;
 388
 389         return (p);
 390  bad:
 391         (void)close(fd);
 392         /*
 393          * Get rid of any link-layer type list we allocated.
 394          */
 395         if (p->dlt_list != NULL)
 396                 free(p->dlt_list);
 397         free(p);
 398         return (NULL);
 399 }
 400
 401 int
 402 pcap_platform_finddevs(pcap_if_t **alldevsp, char *errbuf)
 403 {
 404         return (0);
 405 }