1 /* $OpenBSD: inet.c,v 1.12 2000/04/13 05:55:19 itojun Exp $ */ 2 3 /* 4 * Copyright (c) 1994, 1995, 1996, 1997, 1998 5 * The Regents of the University of California. All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 3. All advertising materials mentioning features or use of this software 16 * must display the following acknowledgement: 17 * This product includes software developed by the Computer Systems 18 * Engineering Group at Lawrence Berkeley Laboratory. 19 * 4. Neither the name of the University nor of the Laboratory may be used 20 * to endorse or promote products derived from this software without 21 * specific prior written permission. 22 * 23 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 24 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 25 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 26 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 27 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 28 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 29 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 30 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 31 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 32 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 33 * SUCH DAMAGE. 34 */ 35 36 #ifndef lint 37 static const char rcsid[] = 38 "@(#) $Header: /home/cvs/src/lib/libpcap/inet.c,v 1.12 2000/04/13 05:55:19 itojun Exp $ (LBL)"; 39 #endif 40 41 #include <sys/param.h> 42 #include <sys/file.h> 43 #include <sys/ioctl.h> 44 #include <sys/socket.h> 45 #ifdef HAVE_SYS_SOCKIO_H 46 #include <sys/sockio.h> 47 #endif 48 #include <sys/time.h> /* concession to AIX */ 49 50 #ifdef __STDC__ 51 struct mbuf; 52 struct rtentry; 53 #endif 54 55 #include <net/if.h> 56 #include <netinet/in.h> 57 58 #include <ctype.h> 59 #include <errno.h> 60 #include <memory.h> 61 #include <stdio.h> 62 #include <stdlib.h> 63 #include <string.h> 64 #include <unistd.h> 65 #ifdef HAVE_IFADDRS_H 66 #include <ifaddrs.h> 67 #endif 68 69 #include "pcap-int.h" 70 71 #ifdef HAVE_OS_PROTO_H 72 #include "os-proto.h" 73 #endif 74 75 /* Not all systems have IFF_LOOPBACK */ 76 #ifdef IFF_LOOPBACK 77 #define ISLOOPBACK(p) ((p)->ifr_flags & IFF_LOOPBACK) 78 #else 79 #define ISLOOPBACK(p) ((p)->ifr_name[0] == 'l' && (p)->ifr_name[1] == 'o' && \ 80 (isdigit((p)->ifr_name[2]) || (p)->ifr_name[2] == '\0')) 81 #endif 82 83 /* 84 * Return the name of a network interface attached to the system, or NULL 85 * if none can be found. The interface must be configured up; the 86 * lowest unit number is preferred; loopback is ignored. 87 */ 88 char * 89 pcap_lookupdev(errbuf) 90 register char *errbuf; 91 { 92 #ifdef HAVE_IFADDRS_H 93 struct ifaddrs *ifap, *ifa, *mp; 94 int n, minunit; 95 char *cp; 96 static char device[IF_NAMESIZE + 1]; 97 98 if (getifaddrs(&ifap) != 0) { 99 (void)snprintf(errbuf, PCAP_ERRBUF_SIZE, 100 "getifaddrs: %s", pcap_strerror(errno)); 101 return NULL; 102 } 103 104 mp = NULL; 105 minunit = 666; 106 for (ifa = ifap; ifa; ifa = ifa->ifa_next) { 107 if ((ifa->ifa_flags & IFF_UP) == 0) 108 continue; 109 #ifdef IFF_LOOPBACK 110 if ((ifa->ifa_flags & IFF_LOOPBACK) != 0) 111 continue; 112 #else 113 if (strncmp(ifa->ifa_name, "lo", 2) == 0 && 114 (ifa->ifa_name[2] == '\0' || isdigit(ifa->ifa_name[2]))) { 115 continue; 116 } 117 #endif 118 119 for (cp = ifa->ifa_name; !isdigit(*cp); ++cp) 120 continue; 121 n = atoi(cp); 122 if (n < minunit) { 123 minunit = n; 124 mp = ifa; 125 } 126 } 127 if (mp == NULL) { 128 (void)strncpy(errbuf, "no suitable device found", 129 PCAP_ERRBUF_SIZE); 130 freeifaddrs(ifap); 131 return (NULL); 132 } 133 134 (void)strncpy(device, mp->ifa_name, sizeof(device) - 1); 135 device[sizeof(device) - 1] = '\0'; 136 freeifaddrs(ifap); 137 return (device); 138 #else 139 register int fd, minunit, n; 140 register char *cp, *ibuf = NULL, *nibuf; 141 register struct ifreq *ifrp, *ifend, *ifnext, *mp; 142 struct ifconf ifc; 143 struct ifreq ifr; 144 static char device[sizeof(ifrp->ifr_name) + 1]; 145 int len = 8192; 146 147 fd = socket(AF_INET, SOCK_DGRAM, 0); 148 if (fd < 0) { 149 (void)snprintf(errbuf, PCAP_ERRBUF_SIZE, "socket: %s", 150 pcap_strerror(errno)); 151 return (NULL); 152 } 153 while (1) { 154 ifc.ifc_len = len; 155 nibuf = realloc(ibuf, len); 156 if (nibuf == NULL) { 157 if (ibuf) 158 free(ibuf); 159 close(fd); 160 return (NULL); 161 } 162 ifc.ifc_buf = ibuf = nibuf; 163 if (ioctl(fd, SIOCGIFCONF, (char *)&ifc) < 0) { 164 (void)close(fd); 165 free(ibuf); 166 return (NULL); 167 } 168 if (ifc.ifc_len + sizeof(ifr) < len) 169 break; 170 len *= 2; 171 } 172 173 ifrp = (struct ifreq *)ibuf; 174 ifend = (struct ifreq *)((char *)ibuf + ifc.ifc_len); 175 176 mp = NULL; 177 minunit = 666; 178 for (; ifrp < ifend; ifrp = ifnext) { 179 #if BSD - 0 >= 199006 180 n = ifrp->ifr_addr.sa_len + sizeof(ifrp->ifr_name); 181 if (n < sizeof(*ifrp)) 182 ifnext = ifrp + 1; 183 else 184 ifnext = (struct ifreq *)((char *)ifrp + n); 185 if (ifrp->ifr_addr.sa_family != AF_INET) 186 continue; 187 #else 188 ifnext = ifrp + 1; 189 #endif 190 /* 191 * Need a template to preserve address info that is 192 * used below to locate the next entry. (Otherwise, 193 * SIOCGIFFLAGS stomps over it because the requests 194 * are returned in a union.) 195 */ 196 strncpy(ifr.ifr_name, ifrp->ifr_name, sizeof(ifr.ifr_name)); 197 if (ioctl(fd, SIOCGIFFLAGS, (char *)&ifr) < 0) { 198 if (errno == ENXIO) 199 continue; 200 (void)snprintf(errbuf, PCAP_ERRBUF_SIZE, 201 "SIOCGIFFLAGS: %.*s: %s", 202 (int)sizeof(ifr.ifr_name), ifr.ifr_name, 203 pcap_strerror(errno)); 204 (void)close(fd); 205 free(ibuf); 206 return (NULL); 207 } 208 209 /* Must be up and not the loopback */ 210 if ((ifr.ifr_flags & IFF_UP) == 0 || ISLOOPBACK(&ifr)) 211 continue; 212 213 for (cp = ifrp->ifr_name; !isdigit(*cp); ++cp) 214 continue; 215 n = atoi(cp); 216 if (n < minunit) { 217 minunit = n; 218 mp = ifrp; 219 } 220 } 221 (void)close(fd); 222 if (mp == NULL) { 223 (void)strlcpy(errbuf, "no suitable device found", 224 PCAP_ERRBUF_SIZE); 225 free(ibuf); 226 return (NULL); 227 } 228 229 (void)strncpy(device, mp->ifr_name, sizeof(device) - 1); 230 device[sizeof(device) - 1] = '\0'; 231 free(ibuf); 232 return (device); 233 #endif 234 } 235 236 int 237 pcap_lookupnet(device, netp, maskp, errbuf) 238 register char *device; 239 register bpf_u_int32 *netp, *maskp; 240 register char *errbuf; 241 { 242 register int fd; 243 register struct sockaddr_in *sin; 244 struct ifreq ifr; 245 246 fd = socket(AF_INET, SOCK_DGRAM, 0); 247 if (fd < 0) { 248 (void)snprintf(errbuf, PCAP_ERRBUF_SIZE, "socket: %s", 249 pcap_strerror(errno)); 250 return (-1); 251 } 252 memset(&ifr, 0, sizeof(ifr)); 253 #ifdef linux 254 /* XXX Work around Linux kernel bug */ 255 ifr.ifr_addr.sa_family = AF_INET; 256 #endif 257 (void)strncpy(ifr.ifr_name, device, sizeof(ifr.ifr_name)); 258 if (ioctl(fd, SIOCGIFADDR, (char *)&ifr) < 0) { 259 (void)snprintf(errbuf, PCAP_ERRBUF_SIZE, "SIOCGIFADDR: %s: %s", 260 device, pcap_strerror(errno)); 261 (void)close(fd); 262 return (-1); 263 } 264 sin = (struct sockaddr_in *)&ifr.ifr_addr; 265 *netp = sin->sin_addr.s_addr; 266 if (ioctl(fd, SIOCGIFNETMASK, (char *)&ifr) < 0) { 267 (void)snprintf(errbuf, PCAP_ERRBUF_SIZE, "SIOCGIFNETMASK: %s: %s", 268 device, pcap_strerror(errno)); 269 (void)close(fd); 270 return (-1); 271 } 272 (void)close(fd); 273 *maskp = sin->sin_addr.s_addr; 274 if (*maskp == 0) { 275 if (IN_CLASSA(*netp)) 276 *maskp = IN_CLASSA_NET; 277 else if (IN_CLASSB(*netp)) 278 *maskp = IN_CLASSB_NET; 279 else if (IN_CLASSC(*netp)) 280 *maskp = IN_CLASSC_NET; 281 else { 282 (void)snprintf(errbuf, PCAP_ERRBUF_SIZE, 283 "inet class for 0x%x unknown", *netp); 284 return (-1); 285 } 286 } 287 *netp &= *maskp; 288 return (0); 289 } 290