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 1.31 2001-06-05 03:48:41 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 = sh->snoop_timestamp;
  96                 h.len = datalen;
  97                 h.caplen = caplen;
  98                 (*callback)(user, &h, cp);
  99                 return (1);
 100         }
 101         return (0);
 102 }
 103
 104 int
 105 pcap_stats(pcap_t *p, struct pcap_stat *ps)
 106 {
 107         register struct rawstats *rs;
 108         struct rawstats rawstats;
 109
 110         rs = &rawstats;
 111         memset(rs, 0, sizeof(*rs));
 112         if (ioctl(p->fd, SIOCRAWSTATS, (char *)rs) < 0) {
 113                 snprintf(p->errbuf, sizeof(p->errbuf),
 114                     "SIOCRAWSTATS: %s", pcap_strerror(errno));
 115                 return (-1);
 116         }
 117
 118         p->md.stat.ps_drop =
 119             rs->rs_snoop.ss_ifdrops + rs->rs_snoop.ss_sbdrops +
 120             rs->rs_drain.ds_ifdrops + rs->rs_drain.ds_sbdrops;
 121
 122         *ps = p->md.stat;
 123         return (0);
 124 }
 125
 126 /* XXX can't disable promiscuous */
 127 pcap_t *
 128 pcap_open_live(char *device, int snaplen, int promisc, int to_ms, char *ebuf)
 129 {
 130         int fd;
 131         struct sockaddr_raw sr;
 132         struct snoopfilter sf;
 133         u_int v;
 134         int ll_hdrlen;
 135         int snooplen;
 136         pcap_t *p;
 137         struct ifreq ifr;
 138
 139         p = (pcap_t *)malloc(sizeof(*p));
 140         if (p == NULL) {
 141                 snprintf(ebuf, PCAP_ERRBUF_SIZE, "malloc: %s",
 142                     pcap_strerror(errno));
 143                 return (NULL);
 144         }
 145         memset(p, 0, sizeof(*p));
 146         fd = socket(PF_RAW, SOCK_RAW, RAWPROTO_SNOOP);
 147         if (fd < 0) {
 148                 snprintf(ebuf, PCAP_ERRBUF_SIZE, "snoop socket: %s",
 149                     pcap_strerror(errno));
 150                 goto bad;
 151         }
 152         p->fd = fd;
 153         memset(&sr, 0, sizeof(sr));
 154         sr.sr_family = AF_RAW;
 155         (void)strncpy(sr.sr_ifname, device, sizeof(sr.sr_ifname));
 156         if (bind(fd, (struct sockaddr *)&sr, sizeof(sr))) {
 157                 snprintf(ebuf, PCAP_ERRBUF_SIZE, "snoop bind: %s",
 158                     pcap_strerror(errno));
 159                 goto bad;
 160         }
 161         memset(&sf, 0, sizeof(sf));
 162         if (ioctl(fd, SIOCADDSNOOP, &sf) < 0) {
 163                 snprintf(ebuf, PCAP_ERRBUF_SIZE, "SIOCADDSNOOP: %s",
 164                     pcap_strerror(errno));
 165                 goto bad;
 166         }
 167         v = 64 * 1024;
 168         (void)setsockopt(fd, SOL_SOCKET, SO_RCVBUF, (char *)&v, sizeof(v));
 169         /*
 170          * XXX hack - map device name to link layer type
 171          */
 172         if (strncmp("et", device, 2) == 0 ||    /* Challenge 10 Mbit */
 173             strncmp("ec", device, 2) == 0 ||    /* Indigo/Indy 10 Mbit,
 174                                                    O2 10/100 */
 175             strncmp("ef", device, 2) == 0 ||    /* O200/2000 10/100 Mbit */
 176             strncmp("gfe", device, 3) == 0 ||   /* GIO 100 Mbit */
 177             strncmp("fxp", device, 3) == 0 ||   /* Challenge VME Enet */
 178             strncmp("ep", device, 2) == 0 ||    /* Challenge 8x10 Mbit EPLEX */
 179             strncmp("vfe", device, 3) == 0 ||   /* Challenge VME 100Mbit */
 180             strncmp("fa", device, 2) == 0 ||
 181             strncmp("qaa", device, 3) == 0 ||
 182             strncmp("cip", device, 3) == 0 ||
 183             strncmp("el", device, 2) == 0) {
 184                 p->linktype = DLT_EN10MB;
 185                 p->offset = RAW_HDRPAD(sizeof(struct ether_header));
 186                 ll_hdrlen = sizeof(struct ether_header);
 187         } else if (strncmp("ipg", device, 3) == 0 ||
 188                    strncmp("rns", device, 3) == 0 ||    /* O2/200/2000 FDDI */
 189                    strncmp("xpi", device, 3) == 0) {
 190                 p->linktype = DLT_FDDI;
 191                 p->offset = 3;                          /* XXX yeah? */
 192                 ll_hdrlen = 13;
 193         } else if (strncmp("ppp", device, 3) == 0) {
 194                 p->linktype = DLT_RAW;
 195                 ll_hdrlen = 0;  /* DLT_RAW meaning "no PPP header, just the IP packet"? */
 196         } else if (strncmp("lo", device, 2) == 0) {
 197                 p->linktype = DLT_NULL;
 198                 ll_hdrlen = 4;  /* is this just like BSD's loopback device? */
 199         } else {
 200                 snprintf(ebuf, PCAP_ERRBUF_SIZE,
 201                     "snoop: unknown physical layer type");
 202                 goto bad;
 203         }
 204 #ifdef SIOCGIFMTU
 205         /*
 206          * XXX - IRIX appears to give you an error if you try to set the
 207          * capture length to be greater than the MTU, so let's try to get
 208          * the MTU first and, if that succeeds, trim the snap length
 209          * to be no greater than the MTU.
 210          */
 211         (void)strncpy(ifr.ifr_name, device, sizeof(ifr.ifr_name));
 212         if (ioctl(fd, SIOCGIFMTU, (char *)&ifr) < 0) {
 213                 snprintf(ebuf, PCAP_ERRBUF_SIZE, "SIOCGIFMTU: %s",
 214                     pcap_strerror(errno));
 215                 goto bad;
 216         }
 217         /*
 218          * OK, we got it.
 219          *
 220          * XXX - some versions of IRIX 6.5 define "ifr_mtu" and have an
 221          * "ifru_metric" member of the "ifr_ifru" union in an "ifreq"
 222          * structure, others don't.
 223          *
 224          * I've no idea what's going on, so, if "ifr_mtu" isn't defined,
 225          * we define it as "ifr_metric", as using that field appears to
 226          * work on the versions that lack "ifr_mtu" (and, on those that
 227          * don't lack it, "ifru_metric" and "ifru_mtu" are both "int"
 228          * members of the "ifr_ifru" union, which suggests that they
 229          * may be interchangeable in this case).
 230          */
 231 #ifndef ifr_mtu
 232 #define ifr_mtu ifr_metric
 233 #endif
 234         if (snaplen > ifr.ifr_mtu)
 235                 snaplen = ifr.ifr_mtu;
 236 #endif
 237
 238         /*
 239          * The argument to SIOCSNOOPLEN is the number of link-layer
 240          * payload bytes to capture - it doesn't count link-layer
 241          * header bytes.
 242          */
 243         snooplen = snaplen - ll_hdrlen;
 244         if (snooplen < 0)
 245                 snooplen = 0;
 246         if (ioctl(fd, SIOCSNOOPLEN, &snooplen) < 0) {
 247                 snprintf(ebuf, PCAP_ERRBUF_SIZE, "SIOCSNOOPLEN: %s",
 248                     pcap_strerror(errno));
 249                 goto bad;
 250         }
 251         p->snapshot = snaplen;
 252         v = 1;
 253         if (ioctl(fd, SIOCSNOOPING, &v) < 0) {
 254                 snprintf(ebuf, PCAP_ERRBUF_SIZE, "SIOCSNOOPING: %s",
 255                     pcap_strerror(errno));
 256                 goto bad;
 257         }
 258
 259         p->bufsize = 4096;                              /* XXX */
 260         p->buffer = (u_char *)malloc(p->bufsize);
 261         if (p->buffer == NULL) {
 262                 snprintf(ebuf, PCAP_ERRBUF_SIZE, "malloc: %s",
 263                     pcap_strerror(errno));
 264                 goto bad;
 265         }
 266
 267         return (p);
 268  bad:
 269         (void)close(fd);
 270         free(p);
 271         return (NULL);
 272 }
 273
 274 int
 275 pcap_setfilter(pcap_t *p, struct bpf_program *fp)
 276 {
 277
 278         if (install_bpf_program(p, fp) < 0)
 279                 return (-1);
 280         return (0);
 281 }