pcap/inet.c

   1 /*
   2  * Copyright (c) 1999 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_LICENSE_HEADER_START@
   5  *
   6  * "Portions Copyright (c) 1999 Apple Computer, Inc.  All Rights
   7  * Reserved.  This file contains Original Code and/or Modifications of
   8  * Original Code as defined in and that are subject to the Apple Public
   9  * Source License Version 1.0 (the 'License').  You may not use this file
  10  * except in compliance with the License.  Please obtain a copy of the
  11  * License at http://www.apple.com/publicsource and read it before using
  12  * this file.
  13  *
  14  * The Original Code and all software distributed under the License are
  15  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  16  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  17  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  18  * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT.  Please see the
  19  * License for the specific language governing rights and limitations
  20  * under the License."
  21  *
  22  * @APPLE_LICENSE_HEADER_END@
  23  */
  24 /*      $OpenBSD: inet.c,v 1.6 1997/01/24 19:17:25 deraadt Exp $        */
  25
  26 /*
  27  * Copyright (c) 1994, 1995, 1996
  28  *      The Regents of the University of California.  All rights reserved.
  29  *
  30  * Redistribution and use in source and binary forms, with or without
  31  * modification, are permitted provided that the following conditions
  32  * are met:
  33  * 1. Redistributions of source code must retain the above copyright
  34  *    notice, this list of conditions and the following disclaimer.
  35  * 2. Redistributions in binary form must reproduce the above copyright
  36  *    notice, this list of conditions and the following disclaimer in the
  37  *    documentation and/or other materials provided with the distribution.
  38  * 3. All advertising materials mentioning features or use of this software
  39  *    must display the following acknowledgement:
  40  *      This product includes software developed by the Computer Systems
  41  *      Engineering Group at Lawrence Berkeley Laboratory.
  42  * 4. Neither the name of the University nor of the Laboratory may be used
  43  *    to endorse or promote products derived from this software without
  44  *    specific prior written permission.
  45  *
  46  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  47  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  48  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  49  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  50  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  51  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  52  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  53  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  54  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  55  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  56  * SUCH DAMAGE.
  57  */
  58
  59 #ifndef lint
  60 static char rcsid[] =
  61     "@(#) Header: inet.c,v 1.16 96/06/23 14:28:22 leres Exp (LBL)";
  62 #endif
  63
  64 #include <sys/param.h>
  65 #include <sys/file.h>
  66 #include <sys/ioctl.h>
  67 #include <sys/socket.h>
  68 #ifdef HAVE_SYS_SOCKIO_H
  69 #include <sys/sockio.h>
  70 #endif
  71
  72 #if __STDC__
  73 struct mbuf;
  74 struct rtentry;
  75 #endif
  76
  77 #include <net/if.h>
  78 #include <netinet/in.h>
  79
  80 #include <ctype.h>
  81 #include <errno.h>
  82 #include <memory.h>
  83 #include <stdio.h>
  84 #include <stdlib.h>
  85 #include <string.h>
  86 #include <unistd.h>
  87 #include <pcap.h>
  88
  89 #ifdef HAVE_OS_PROTO_H
  90 #include "os-proto.h"
  91 #endif
  92
  93 #include "pcap-int.h"
  94
  95 /* Not all systems have IFF_LOOPBACK */
  96 #ifdef IFF_LOOPBACK
  97 #define ISLOOPBACK(p) ((p)->ifr_flags & IFF_LOOPBACK)
  98 #else
  99 #define ISLOOPBACK(p) (strcmp((p)->ifr_name, "lo0") == 0)
 100 #endif
 101
 102 /*
 103  * Return the name of a network interface attached to the system, or NULL
 104  * if none can be found.  The interface must be configured up; the
 105  * lowest unit number is preferred; loopback is ignored.
 106  */
 107 char *
 108 pcap_lookupdev(errbuf)
 109         register char *errbuf;
 110 {
 111         register int fd, minunit, n;
 112         register char *cp, *ibuf = NULL;
 113         register struct ifreq *ifrp, *ifend, *ifnext, *mp;
 114         struct ifconf ifc;
 115         struct ifreq ifr;
 116         static char device[sizeof(ifrp->ifr_name) + 1];
 117         int len = 8192;
 118
 119         fd = socket(AF_INET, SOCK_DGRAM, 0);
 120         if (fd < 0) {
 121                 (void)sprintf(errbuf, "socket: %s", pcap_strerror(errno));
 122                 return (NULL);
 123         }
 124         while (1) {
 125                 ifc.ifc_len = len;
 126                 ifc.ifc_buf = ibuf = realloc(ibuf, len);
 127                 if (ibuf == NULL) {
 128                         close(fd);
 129                         return (NULL);
 130                 }
 131                 if (ioctl(fd, SIOCGIFCONF, (char *)&ifc) < 0) {
 132                         (void)close(fd);
 133                         free(ibuf);
 134                         return (NULL);
 135                 }
 136                 if (ifc.ifc_len + sizeof(ifr) < len)
 137                         break;
 138                 len *= 2;
 139         }
 140
 141         ifrp = (struct ifreq *)ibuf;
 142         ifend = (struct ifreq *)((char *)ibuf + ifc.ifc_len);
 143
 144         mp = NULL;
 145         minunit = 666;
 146         for (; ifrp < ifend; ifrp = ifnext) {
 147 #if BSD - 0 >= 199006
 148                 n = ifrp->ifr_addr.sa_len + sizeof(ifrp->ifr_name);
 149                 if (n < sizeof(*ifrp))
 150                         ifnext = ifrp + 1;
 151                 else
 152                         ifnext = (struct ifreq *)((char *)ifrp + n);
 153                 if (ifrp->ifr_addr.sa_family != AF_INET)
 154                         continue;
 155 #else
 156                 ifnext = ifrp + 1;
 157 #endif
 158                 /*
 159                  * Need a template to preserve address info that is
 160                  * used below to locate the next entry.  (Otherwise,
 161                  * SIOCGIFFLAGS stomps over it because the requests
 162                  * are returned in a union.)
 163                  */
 164                 strncpy(ifr.ifr_name, ifrp->ifr_name, sizeof(ifr.ifr_name));
 165                 if (ioctl(fd, SIOCGIFFLAGS, (char *)&ifr) < 0) {
 166                         (void)sprintf(errbuf, "SIOCGIFFLAGS: %s",
 167                             pcap_strerror(errno));
 168                         (void)close(fd);
 169                         free(ibuf);
 170                         return (NULL);
 171                 }
 172
 173                 /* Must be up and not the loopback */
 174                 if ((ifr.ifr_flags & IFF_UP) == 0 || ISLOOPBACK(&ifr))
 175                         continue;
 176
 177                 for (cp = ifrp->ifr_name; !isdigit(*cp); ++cp)
 178                         continue;
 179                 n = atoi(cp);
 180                 if (n < minunit) {
 181                         minunit = n;
 182                         mp = ifrp;
 183                 }
 184         }
 185         free(ibuf);
 186         (void)close(fd);
 187         if (mp == NULL) {
 188                 (void)strcpy(errbuf, "no suitable device found");
 189                 return (NULL);
 190         }
 191
 192         (void)strncpy(device, mp->ifr_name, sizeof(device) - 1);
 193         device[sizeof(device) - 1] = '\0';
 194         return (device);
 195 }
 196
 197 int
 198 pcap_lookupnet(device, netp, maskp, errbuf)
 199         register char *device;
 200         register bpf_u_int32 *netp, *maskp;
 201         register char *errbuf;
 202 {
 203         register int fd;
 204         register struct sockaddr_in *sin;
 205         struct ifreq ifr;
 206
 207         fd = socket(AF_INET, SOCK_DGRAM, 0);
 208         if (fd < 0) {
 209                 (void)sprintf(errbuf, "socket: %s", pcap_strerror(errno));
 210                 return (-1);
 211         }
 212         memset(&ifr, 0, sizeof(ifr));
 213 #ifdef linux
 214         /* XXX Work around Linux kernel bug */
 215         ifr.ifr_addr.sa_family = AF_INET;
 216 #endif
 217         (void)strncpy(ifr.ifr_name, device, sizeof(ifr.ifr_name));
 218         if (ioctl(fd, SIOCGIFADDR, (char *)&ifr) < 0) {
 219                 (void)sprintf(errbuf, "SIOCGIFADDR: %s: %s",
 220                     device, pcap_strerror(errno));
 221                 (void)close(fd);
 222                 return (-1);
 223         }
 224         sin = (struct sockaddr_in *)&ifr.ifr_addr;
 225         *netp = sin->sin_addr.s_addr;
 226         if (ioctl(fd, SIOCGIFNETMASK, (char *)&ifr) < 0) {
 227                 (void)sprintf(errbuf, "SIOCGIFNETMASK: %s: %s",
 228                     device, pcap_strerror(errno));
 229                 (void)close(fd);
 230                 return (-1);
 231         }
 232         (void)close(fd);
 233         *maskp = sin->sin_addr.s_addr;
 234         if (*maskp == 0) {
 235                 if (IN_CLASSA(*netp))
 236                         *maskp = IN_CLASSA_NET;
 237                 else if (IN_CLASSB(*netp))
 238                         *maskp = IN_CLASSB_NET;
 239                 else if (IN_CLASSC(*netp))
 240                         *maskp = IN_CLASSC_NET;
 241                 else {
 242                         (void)sprintf(errbuf, "inet class for 0x%x unknown",
 243                             *netp);
 244                         return (-1);
 245                 }
 246         }
 247         *netp &= *maskp;
 248         return (0);
 249 }