The Tcpdump Group git mirrors - libpcap/blob - pcap.c

   1 /*
   2  * Copyright (c) 1993, 1994, 1995, 1996, 1997, 1998
   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 the following conditions
   7  * are met:
   8  * 1. Redistributions of source code must retain the above copyright
   9  *    notice, this list of conditions and the following disclaimer.
  10  * 2. Redistributions in binary form must reproduce the above copyright
  11  *    notice, this list of conditions and the following disclaimer in the
  12  *    documentation and/or other materials provided with the distribution.
  13  * 3. All advertising materials mentioning features or use of this software
  14  *    must display the following acknowledgement:
  15  *      This product includes software developed by the Computer Systems
  16  *      Engineering Group at Lawrence Berkeley Laboratory.
  17  * 4. Neither the name of the University nor of the Laboratory may be used
  18  *    to endorse or promote products derived from this software without
  19  *    specific prior written permission.
  20  *
  21  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  31  * SUCH DAMAGE.
  32  */
  33
  34 #ifndef lint
  35 static const char rcsid[] =
  36     "@(#) $Header: /tcpdump/master/libpcap/pcap.c,v 1.34 2000-10-25 06:59:10 guy Exp $ (LBL)";
  37 #endif
  38
  39 #ifdef HAVE_CONFIG_H
  40 #include "config.h"
  41 #endif
  42
  43 #include <sys/types.h>
  44
  45 #include <stdio.h>
  46 #include <stdlib.h>
  47 #include <string.h>
  48 #include <unistd.h>
  49
  50 #ifdef HAVE_OS_PROTO_H
  51 #include "os-proto.h"
  52 #endif
  53
  54 #include "pcap-int.h"
  55
  56 int
  57 pcap_dispatch(pcap_t *p, int cnt, pcap_handler callback, u_char *user)
  58 {
  59
  60         if (p->sf.rfile != NULL)
  61                 return (pcap_offline_read(p, cnt, callback, user));
  62         return (pcap_read(p, cnt, callback, user));
  63 }
  64
  65 int
  66 pcap_loop(pcap_t *p, int cnt, pcap_handler callback, u_char *user)
  67 {
  68         register int n;
  69
  70         for (;;) {
  71                 if (p->sf.rfile != NULL)
  72                         n = pcap_offline_read(p, cnt, callback, user);
  73                 else {
  74                         /*
  75                          * XXX keep reading until we get something
  76                          * (or an error occurs)
  77                          */
  78                         do {
  79                                 n = pcap_read(p, cnt, callback, user);
  80                         } while (n == 0);
  81                 }
  82                 if (n <= 0)
  83                         return (n);
  84                 if (cnt > 0) {
  85                         cnt -= n;
  86                         if (cnt <= 0)
  87                                 return (0);
  88                 }
  89         }
  90 }
  91
  92 struct singleton {
  93         struct pcap_pkthdr *hdr;
  94         const u_char *pkt;
  95 };
  96
  97
  98 static void
  99 pcap_oneshot(u_char *userData, const struct pcap_pkthdr *h, const u_char *pkt)
 100 {
 101         struct singleton *sp = (struct singleton *)userData;
 102         *sp->hdr = *h;
 103         sp->pkt = pkt;
 104 }
 105
 106 const u_char *
 107 pcap_next(pcap_t *p, struct pcap_pkthdr *h)
 108 {
 109         struct singleton s;
 110
 111         s.hdr = h;
 112         if (pcap_dispatch(p, 1, pcap_oneshot, (u_char*)&s) <= 0)
 113                 return (0);
 114         return (s.pkt);
 115 }
 116
 117 int
 118 pcap_datalink(pcap_t *p)
 119 {
 120         return (p->linktype);
 121 }
 122
 123 int
 124 pcap_snapshot(pcap_t *p)
 125 {
 126         return (p->snapshot);
 127 }
 128
 129 int
 130 pcap_is_swapped(pcap_t *p)
 131 {
 132         return (p->sf.swapped);
 133 }
 134
 135 int
 136 pcap_major_version(pcap_t *p)
 137 {
 138         return (p->sf.version_major);
 139 }
 140
 141 int
 142 pcap_minor_version(pcap_t *p)
 143 {
 144         return (p->sf.version_minor);
 145 }
 146
 147 FILE *
 148 pcap_file(pcap_t *p)
 149 {
 150         return (p->sf.rfile);
 151 }
 152
 153 int
 154 pcap_fileno(pcap_t *p)
 155 {
 156         return (p->fd);
 157 }
 158
 159 void
 160 pcap_perror(pcap_t *p, char *prefix)
 161 {
 162         fprintf(stderr, "%s: %s\n", prefix, p->errbuf);
 163 }
 164
 165 char *
 166 pcap_geterr(pcap_t *p)
 167 {
 168         return (p->errbuf);
 169 }
 170
 171 /*
 172  * Not all systems have strerror().
 173  */
 174 char *
 175 pcap_strerror(int errnum)
 176 {
 177 #ifdef HAVE_STRERROR
 178         return (strerror(errnum));
 179 #else
 180         extern int sys_nerr;
 181         extern const char *const sys_errlist[];
 182         static char ebuf[20];
 183
 184         if ((unsigned int)errnum < sys_nerr)
 185                 return ((char *)sys_errlist[errnum]);
 186         (void)snprintf(ebuf, sizeof ebuf, "Unknown error: %d", errnum);
 187         return(ebuf);
 188 #endif
 189 }
 190
 191 pcap_t *
 192 pcap_open_dead(int linktype, int snaplen)
 193 {
 194         pcap_t *p;
 195
 196         p = malloc(sizeof(*p));
 197         if (p == NULL)
 198                 return NULL;
 199         memset (p, 0, sizeof(*p));
 200         p->fd = -1;
 201         p->snapshot = snaplen;
 202         p->linktype = linktype;
 203         return p;
 204 }
 205
 206 void
 207 pcap_close(pcap_t *p)
 208 {
 209         /*XXX*/
 210         if (p->fd >= 0)
 211                 close(p->fd);
 212         if (p->sf.rfile != NULL) {
 213                 if (p->sf.rfile != stdin)
 214                         (void)fclose(p->sf.rfile);
 215                 if (p->sf.base != NULL)
 216                         free(p->sf.base);
 217         } else if (p->buffer != NULL)
 218                 free(p->buffer);
 219 #ifdef linux
 220         if (p->md.device != NULL)
 221                 free(p->md.device);
 222         pcap_freecode(p, &p->fcode);
 223 #endif
 224
 225         free(p);
 226 }