1 /* $OpenBSD: inet.c,v 1.15 2004/01/21 00:30:15 jfb 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 1.15 2004/01/21 00:30:15 jfb 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 struct mbuf; 51 struct rtentry; 52 53 #include <net/if.h> 54 #include <netinet/in.h> 55 56 #include <ctype.h> 57 #include <errno.h> 58 #include <memory.h> 59 #include <stdio.h> 60 #include <stdlib.h> 61 #include <string.h> 62 #include <unistd.h> 63 #ifdef HAVE_IFADDRS_H 64 #include <ifaddrs.h> 65 #endif 66 67 #include "pcap-int.h" 68 69 #ifdef HAVE_OS_PROTO_H 70 #include "os-proto.h" 71 #endif 72 73 /* Not all systems have IFF_LOOPBACK */ 74 #ifdef IFF_LOOPBACK 75 #define ISLOOPBACK(p) ((p)->ifr_flags & IFF_LOOPBACK) 76 #else 77 #define ISLOOPBACK(p) ((p)->ifr_name[0] == 'l' && (p)->ifr_name[1] == 'o' && \ 78 (isdigit((p)->ifr_name[2]) || (p)->ifr_name[2] == '\0')) 79 #endif 80 81 /* 82 * Return the name of a network interface attached to the system, or NULL 83 * if none can be found. The interface must be configured up; the 84 * lowest unit number is preferred; loopback is ignored. 85 */ 86 char * 87 pcap_lookupdev(errbuf) 88 register char *errbuf; 89 { 90 #ifdef HAVE_IFADDRS_H 91 struct ifaddrs *ifap, *ifa, *mp; 92 int n, minunit; 93 char *cp; 94 static char device[IF_NAMESIZE + 1]; 95 96 if (getifaddrs(&ifap) != 0) { 97 (void)snprintf(errbuf, PCAP_ERRBUF_SIZE, 98 "getifaddrs: %s", pcap_strerror(errno)); 99 return NULL; 100 } 101 102 mp = NULL; 103 minunit = 666; 104 for (ifa = ifap; ifa; ifa = ifa->ifa_next) { 105 if ((ifa->ifa_flags & IFF_UP) == 0) 106 continue; 107 #ifdef IFF_LOOPBACK 108 if ((ifa->ifa_flags & IFF_LOOPBACK) != 0) 109 continue; 110 #else 111 if (strncmp(ifa->ifa_name, "lo", 2) == 0 && 112 (ifa->ifa_name[2] == '\0' || isdigit(ifa->ifa_name[2]))) { 113 continue; 114 } 115 #endif 116 117 for (cp = ifa->ifa_name; !isdigit(*cp); ++cp) 118 continue; 119 n = atoi(cp); 120 if (n < minunit) { 121 minunit = n; 122 mp = ifa; 123 } 124 } 125 if (mp == NULL) { 126 (void)strlcpy(errbuf, "no suitable device found", 127 PCAP_ERRBUF_SIZE); 128 freeifaddrs(ifap); 129 return (NULL); 130 } 131 132 (void)strlcpy(device, mp->ifa_name, sizeof(device)); 133 freeifaddrs(ifap); 134 return (device); 135 #else 136 register int fd, minunit, n; 137 register char *cp; 138 register struct ifreq *ifrp, *ifend, *ifnext, *mp; 139 struct ifconf ifc; 140 struct ifreq ibuf[16], ifr; 141 static char device[sizeof(ifrp->ifr_name) + 1]; 142 143 fd = socket(AF_INET, SOCK_DGRAM, 0); 144 if (fd < 0) { 145 (void)snprintf(errbuf, PCAP_ERRBUF_SIZE, "socket: %s", 146 pcap_strerror(errno)); 147 return (NULL); 148 } 149 ifc.ifc_len = sizeof ibuf; 150 ifc.ifc_buf = (caddr_t)ibuf; 151 152 memset((char *)ibuf, 0, sizeof(ibuf)); 153 if (ioctl(fd, SIOCGIFCONF, (char *)&ifc) < 0 || 154 ifc.ifc_len < sizeof(struct ifreq)) { 155 (void)snprintf(errbuf, PCAP_ERRBUF_SIZE, "SIOCGIFCONF: %s", 156 pcap_strerror(errno)); 157 (void)close(fd); 158 return (NULL); 159 } 160 ifrp = ibuf; 161 ifend = (struct ifreq *)((char *)ibuf + ifc.ifc_len); 162 163 mp = NULL; 164 minunit = 666; 165 for (; ifrp < ifend; ifrp = ifnext) { 166 #ifdef HAVE_SOCKADDR_SA_LEN 167 n = ifrp->ifr_addr.sa_len + sizeof(ifrp->ifr_name); 168 if (n < sizeof(*ifrp)) 169 ifnext = ifrp + 1; 170 else 171 ifnext = (struct ifreq *)((char *)ifrp + n); 172 if (ifrp->ifr_addr.sa_family != AF_INET) 173 continue; 174 #else 175 ifnext = ifrp + 1; 176 #endif 177 /* 178 * Need a template to preserve address info that is 179 * used below to locate the next entry. (Otherwise, 180 * SIOCGIFFLAGS stomps over it because the requests 181 * are returned in a union.) 182 */ 183 (void)strlcpy(ifr.ifr_name, ifrp->ifr_name, 184 sizeof(ifr.ifr_name)); 185 if (ioctl(fd, SIOCGIFFLAGS, (char *)&ifr) < 0) { 186 if (errno == ENXIO) 187 continue; 188 (void)snprintf(errbuf, PCAP_ERRBUF_SIZE, 189 "SIOCGIFFLAGS: %.*s: %s", 190 (int)sizeof(ifr.ifr_name), ifr.ifr_name, 191 pcap_strerror(errno)); 192 (void)close(fd); 193 return (NULL); 194 } 195 196 /* Must be up and not the loopback */ 197 if ((ifr.ifr_flags & IFF_UP) == 0 || ISLOOPBACK(&ifr)) 198 continue; 199 200 for (cp = ifrp->ifr_name; !isdigit(*cp); ++cp) 201 continue; 202 n = atoi(cp); 203 if (n < minunit) { 204 minunit = n; 205 mp = ifrp; 206 } 207 } 208 (void)close(fd); 209 if (mp == NULL) { 210 (void)strlcpy(errbuf, "no suitable device found", 211 PCAP_ERRBUF_SIZE); 212 return (NULL); 213 } 214 215 (void)strlcpy(device, mp->ifr_name, sizeof(device)); 216 return (device); 217 #endif 218 } 219 220 int 221 pcap_lookupnet(device, netp, maskp, errbuf) 222 register char *device; 223 register bpf_u_int32 *netp, *maskp; 224 register char *errbuf; 225 { 226 register int fd; 227 register struct sockaddr_in *sin; 228 struct ifreq ifr; 229 230 fd = socket(AF_INET, SOCK_DGRAM, 0); 231 if (fd < 0) { 232 (void)snprintf(errbuf, PCAP_ERRBUF_SIZE, "socket: %s", 233 pcap_strerror(errno)); 234 return (-1); 235 } 236 memset(&ifr, 0, sizeof(ifr)); 237 #ifdef linux 238 /* XXX Work around Linux kernel bug */ 239 ifr.ifr_addr.sa_family = AF_INET; 240 #endif 241 (void)strlcpy(ifr.ifr_name, device, sizeof(ifr.ifr_name)); 242 if (ioctl(fd, SIOCGIFADDR, (char *)&ifr) < 0) { 243 if (errno == EADDRNOTAVAIL) { 244 (void)snprintf(errbuf, PCAP_ERRBUF_SIZE, 245 "%s: no IPv4 address assigned", device); 246 } else { 247 (void)snprintf(errbuf, PCAP_ERRBUF_SIZE, 248 "SIOCGIFADDR: %s: %s", 249 device, pcap_strerror(errno)); 250 } 251 (void)close(fd); 252 return (-1); 253 } 254 sin = (struct sockaddr_in *)&ifr.ifr_addr; 255 *netp = sin->sin_addr.s_addr; 256 if (ioctl(fd, SIOCGIFNETMASK, (char *)&ifr) < 0) { 257 (void)snprintf(errbuf, PCAP_ERRBUF_SIZE, 258 "SIOCGIFNETMASK: %s: %s", device, pcap_strerror(errno)); 259 (void)close(fd); 260 return (-1); 261 } 262 (void)close(fd); 263 *maskp = sin->sin_addr.s_addr; 264 if (*maskp == 0) { 265 if (IN_CLASSA(*netp)) 266 *maskp = IN_CLASSA_NET; 267 else if (IN_CLASSB(*netp)) 268 *maskp = IN_CLASSB_NET; 269 else if (IN_CLASSC(*netp)) 270 *maskp = IN_CLASSC_NET; 271 else { 272 (void)snprintf(errbuf, PCAP_ERRBUF_SIZE, 273 "inet class for 0x%x unknown", *netp); 274 return (-1); 275 } 276 } 277 *netp &= *maskp; 278 return (0); 279 } 280