The Tcpdump Group git mirrors - libpcap/blob - 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[] =
  23     "@(#) $Header: /tcpdump/master/libpcap/pcap-snoop.c,v 1.40 2003-07-25 03:25:47 guy 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 int
  62 pcap_read(pcap_t *p, int cnt, pcap_handler callback, u_char *user)
  63 {
  64         int cc;
  65         register struct snoopheader *sh;
  66         register int datalen;
  67         register int caplen;
  68         register u_char *cp;
  69
  70 again:
  71         cc = read(p->fd, (char *)p->buffer, p->bufsize);
  72         if (cc < 0) {
  73                 /* Don't choke when we get ptraced */
  74                 switch (errno) {
  75
  76                 case EINTR:
  77                                 goto again;
  78
  79                 case EWOULDBLOCK:
  80                         return (0);                     /* XXX */
  81                 }
  82                 snprintf(p->errbuf, sizeof(p->errbuf),
  83                     "read: %s", pcap_strerror(errno));
  84                 return (-1);
  85         }
  86         sh = (struct snoopheader *)p->buffer;
  87         datalen = sh->snoop_packetlen;
  88         caplen = (datalen < p->snapshot) ? datalen : p->snapshot;
  89         cp = (u_char *)(sh + 1) + p->offset;            /* XXX */
  90
  91         if (p->fcode.bf_insns == NULL ||
  92             bpf_filter(p->fcode.bf_insns, cp, datalen, caplen)) {
  93                 struct pcap_pkthdr h;
  94                 ++p->md.stat.ps_recv;
  95                 h.ts.tv_sec = sh->snoop_timestamp.tv_sec;
  96                 h.ts.tv_usec = sh->snoop_timestamp.tv_usec;
  97                 h.len = datalen;
  98                 h.caplen = caplen;
  99                 (*callback)(user, &h, cp);
 100                 return (1);
 101         }
 102         return (0);
 103 }
 104
 105 int
 106 pcap_stats(pcap_t *p, struct pcap_stat *ps)
 107 {
 108         register struct rawstats *rs;
 109         struct rawstats rawstats;
 110
 111         rs = &rawstats;
 112         memset(rs, 0, sizeof(*rs));
 113         if (ioctl(p->fd, SIOCRAWSTATS, (char *)rs) < 0) {
 114                 snprintf(p->errbuf, sizeof(p->errbuf),
 115                     "SIOCRAWSTATS: %s", pcap_strerror(errno));
 116                 return (-1);
 117         }
 118
 119         /*
 120          * "ifdrops" are those dropped by the network interface
 121          * due to resource shortages or hardware errors.
 122          *
 123          * "sbdrops" are those dropped due to socket buffer limits.
 124          *
 125          * As filter is done in userland, "sbdrops" counts packets
 126          * regardless of whether they would've passed the filter.
 127          *
 128          * XXX - does this count *all* Snoop or Drain sockets,
 129          * rather than just this socket?  If not, why does it have
 130          * both Snoop and Drain statistics?
 131          */
 132         p->md.stat.ps_drop =
 133             rs->rs_snoop.ss_ifdrops + rs->rs_snoop.ss_sbdrops +
 134             rs->rs_drain.ds_ifdrops + rs->rs_drain.ds_sbdrops;
 135
 136         /*
 137          * "ps_recv" counts only packets that passed the filter.
 138          * As filtering is done in userland, this does not include
 139          * packets dropped because we ran out of buffer space.
 140          */
 141         *ps = p->md.stat;
 142         return (0);
 143 }
 144
 145 static void
 146 pcap_close_snoop(pcap_t *p)
 147 {
 148         if (p->buffer != NULL)
 149                 free(p->buffer);
 150         if (p->fd >= 0)
 151                 close(p->fd);
 152 }
 153
 154 /* XXX can't disable promiscuous */
 155 pcap_t *
 156 pcap_open_live(const char *device, int snaplen, int promisc, int to_ms,
 157     char *ebuf)
 158 {
 159         int fd;
 160         struct sockaddr_raw sr;
 161         struct snoopfilter sf;
 162         u_int v;
 163         int ll_hdrlen;
 164         int snooplen;
 165         pcap_t *p;
 166         struct ifreq ifr;
 167
 168         p = (pcap_t *)malloc(sizeof(*p));
 169         if (p == NULL) {
 170                 snprintf(ebuf, PCAP_ERRBUF_SIZE, "malloc: %s",
 171                     pcap_strerror(errno));
 172                 return (NULL);
 173         }
 174         memset(p, 0, sizeof(*p));
 175         fd = socket(PF_RAW, SOCK_RAW, RAWPROTO_SNOOP);
 176         if (fd < 0) {
 177                 snprintf(ebuf, PCAP_ERRBUF_SIZE, "snoop socket: %s",
 178                     pcap_strerror(errno));
 179                 goto bad;
 180         }
 181         p->fd = fd;
 182         memset(&sr, 0, sizeof(sr));
 183         sr.sr_family = AF_RAW;
 184         (void)strncpy(sr.sr_ifname, device, sizeof(sr.sr_ifname));
 185         if (bind(fd, (struct sockaddr *)&sr, sizeof(sr))) {
 186                 snprintf(ebuf, PCAP_ERRBUF_SIZE, "snoop bind: %s",
 187                     pcap_strerror(errno));
 188                 goto bad;
 189         }
 190         memset(&sf, 0, sizeof(sf));
 191         if (ioctl(fd, SIOCADDSNOOP, &sf) < 0) {
 192                 snprintf(ebuf, PCAP_ERRBUF_SIZE, "SIOCADDSNOOP: %s",
 193                     pcap_strerror(errno));
 194                 goto bad;
 195         }
 196         v = 64 * 1024;
 197         (void)setsockopt(fd, SOL_SOCKET, SO_RCVBUF, (char *)&v, sizeof(v));
 198         /*
 199          * XXX hack - map device name to link layer type
 200          */
 201         if (strncmp("et", device, 2) == 0 ||    /* Challenge 10 Mbit */
 202             strncmp("ec", device, 2) == 0 ||    /* Indigo/Indy 10 Mbit,
 203                                                    O2 10/100 */
 204             strncmp("ef", device, 2) == 0 ||    /* O200/2000 10/100 Mbit */
 205             strncmp("eg", device, 2) == 0 ||    /* Octane/O2xxx/O3xxx Gigabit */
 206             strncmp("gfe", device, 3) == 0 ||   /* GIO 100 Mbit */
 207             strncmp("fxp", device, 3) == 0 ||   /* Challenge VME Enet */
 208             strncmp("ep", device, 2) == 0 ||    /* Challenge 8x10 Mbit EPLEX */
 209             strncmp("vfe", device, 3) == 0 ||   /* Challenge VME 100Mbit */
 210             strncmp("fa", device, 2) == 0 ||
 211             strncmp("qaa", device, 3) == 0 ||
 212             strncmp("cip", device, 3) == 0 ||
 213             strncmp("el", device, 2) == 0) {
 214                 p->linktype = DLT_EN10MB;
 215                 p->offset = RAW_HDRPAD(sizeof(struct ether_header));
 216                 ll_hdrlen = sizeof(struct ether_header);
 217         } else if (strncmp("ipg", device, 3) == 0 ||
 218                    strncmp("rns", device, 3) == 0 ||    /* O2/200/2000 FDDI */
 219                    strncmp("xpi", device, 3) == 0) {
 220                 p->linktype = DLT_FDDI;
 221                 p->offset = 3;                          /* XXX yeah? */
 222                 ll_hdrlen = 13;
 223         } else if (strncmp("ppp", device, 3) == 0) {
 224                 p->linktype = DLT_RAW;
 225                 ll_hdrlen = 0;  /* DLT_RAW meaning "no PPP header, just the IP packet"? */
 226         } else if (strncmp("lo", device, 2) == 0) {
 227                 p->linktype = DLT_NULL;
 228                 ll_hdrlen = 4;  /* is this just like BSD's loopback device? */
 229         } else {
 230                 snprintf(ebuf, PCAP_ERRBUF_SIZE,
 231                     "snoop: unknown physical layer type");
 232                 goto bad;
 233         }
 234 #ifdef SIOCGIFMTU
 235         /*
 236          * XXX - IRIX appears to give you an error if you try to set the
 237          * capture length to be greater than the MTU, so let's try to get
 238          * the MTU first and, if that succeeds, trim the snap length
 239          * to be no greater than the MTU.
 240          */
 241         (void)strncpy(ifr.ifr_name, device, sizeof(ifr.ifr_name));
 242         if (ioctl(fd, SIOCGIFMTU, (char *)&ifr) < 0) {
 243                 snprintf(ebuf, PCAP_ERRBUF_SIZE, "SIOCGIFMTU: %s",
 244                     pcap_strerror(errno));
 245                 goto bad;
 246         }
 247         /*
 248          * OK, we got it.
 249          *
 250          * XXX - some versions of IRIX 6.5 define "ifr_mtu" and have an
 251          * "ifru_metric" member of the "ifr_ifru" union in an "ifreq"
 252          * structure, others don't.
 253          *
 254          * I've no idea what's going on, so, if "ifr_mtu" isn't defined,
 255          * we define it as "ifr_metric", as using that field appears to
 256          * work on the versions that lack "ifr_mtu" (and, on those that
 257          * don't lack it, "ifru_metric" and "ifru_mtu" are both "int"
 258          * members of the "ifr_ifru" union, which suggests that they
 259          * may be interchangeable in this case).
 260          */
 261 #ifndef ifr_mtu
 262 #define ifr_mtu ifr_metric
 263 #endif
 264         if (snaplen > ifr.ifr_mtu + ll_hdrlen)
 265                 snaplen = ifr.ifr_mtu + ll_hdrlen;
 266 #endif
 267
 268         /*
 269          * The argument to SIOCSNOOPLEN is the number of link-layer
 270          * payload bytes to capture - it doesn't count link-layer
 271          * header bytes.
 272          */
 273         snooplen = snaplen - ll_hdrlen;
 274         if (snooplen < 0)
 275                 snooplen = 0;
 276         if (ioctl(fd, SIOCSNOOPLEN, &snooplen) < 0) {
 277                 snprintf(ebuf, PCAP_ERRBUF_SIZE, "SIOCSNOOPLEN: %s",
 278                     pcap_strerror(errno));
 279                 goto bad;
 280         }
 281         p->snapshot = snaplen;
 282         v = 1;
 283         if (ioctl(fd, SIOCSNOOPING, &v) < 0) {
 284                 snprintf(ebuf, PCAP_ERRBUF_SIZE, "SIOCSNOOPING: %s",
 285                     pcap_strerror(errno));
 286                 goto bad;
 287         }
 288
 289         p->bufsize = 4096;                              /* XXX */
 290         p->buffer = (u_char *)malloc(p->bufsize);
 291         if (p->buffer == NULL) {
 292                 snprintf(ebuf, PCAP_ERRBUF_SIZE, "malloc: %s",
 293                     pcap_strerror(errno));
 294                 goto bad;
 295         }
 296
 297         p->close_op = pcap_close_snoop;
 298
 299         return (p);
 300  bad:
 301         (void)close(fd);
 302         free(p);
 303         return (NULL);
 304 }
 305
 306 int
 307 pcap_platform_finddevs(pcap_if_t **alldevsp, char *errbuf)
 308 {
 309         return (0);
 310 }
 311
 312 int
 313 pcap_setfilter(pcap_t *p, struct bpf_program *fp)
 314 {
 315
 316         if (install_bpf_program(p, fp) < 0)
 317                 return (-1);
 318         return (0);
 319 }
 320
 321 int
 322 pcap_set_datalink_platform(pcap_t *p, int dlt)
 323 {
 324         return (0);
 325 }