1 /* $OpenBSD: inet.c,v 1.19 2006/03/26 20:58:50 djm 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 37 #include <sys/param.h> 38 #include <sys/file.h> 39 #include <sys/ioctl.h> 40 #include <sys/socket.h> 41 #ifdef HAVE_SYS_SOCKIO_H 42 #include <sys/sockio.h> 43 #endif 44 #include <sys/time.h> /* concession to AIX */ 45 46 struct mbuf; 47 struct rtentry; 48 49 #include <net/if.h> 50 #include <netinet/in.h> 51 52 #include <ctype.h> 53 #include <errno.h> 54 #include <memory.h> 55 #include <stdio.h> 56 #include <stdlib.h> 57 #include <string.h> 58 #include <unistd.h> 59 #ifdef HAVE_IFADDRS_H 60 #include <ifaddrs.h> 61 #endif 62 63 #include "pcap-int.h" 64 65 #ifdef HAVE_OS_PROTO_H 66 #include "os-proto.h" 67 #endif 68 69 /* 70 * Free a list of interfaces. 71 */ 72 void 73 pcap_freealldevs(pcap_if_t *alldevs) 74 { 75 pcap_if_t *curdev, *nextdev; 76 pcap_addr_t *curaddr, *nextaddr; 77 78 for (curdev = alldevs; curdev != NULL; curdev = nextdev) { 79 nextdev = curdev->next; 80 81 /* 82 * Free all addresses. 83 */ 84 for (curaddr = curdev->addresses; curaddr != NULL; 85 curaddr = nextaddr) { 86 nextaddr = curaddr->next; 87 if (curaddr->addr) 88 free(curaddr->addr); 89 if (curaddr->netmask) 90 free(curaddr->netmask); 91 if (curaddr->broadaddr) 92 free(curaddr->broadaddr); 93 if (curaddr->dstaddr) 94 free(curaddr->dstaddr); 95 free(curaddr); 96 } 97 98 /* 99 * Free the name string. 100 */ 101 free(curdev->name); 102 103 /* 104 * Free the description string, if any. 105 */ 106 if (curdev->description != NULL) 107 free(curdev->description); 108 109 /* 110 * Free the interface. 111 */ 112 free(curdev); 113 } 114 } 115 116 /* 117 * Return the name of a network interface attached to the system, or NULL 118 * if none can be found. The interface must be configured up; the 119 * lowest unit number is preferred; loopback is ignored. 120 */ 121 char * 122 pcap_lookupdev(errbuf) 123 register char *errbuf; 124 { 125 #ifdef HAVE_IFADDRS_H 126 struct ifaddrs *ifap, *ifa, *mp; 127 int n, minunit; 128 char *cp; 129 static char device[IF_NAMESIZE + 1]; 130 131 if (getifaddrs(&ifap) != 0) { 132 (void)snprintf(errbuf, PCAP_ERRBUF_SIZE, 133 "getifaddrs: %s", pcap_strerror(errno)); 134 return NULL; 135 } 136 137 mp = NULL; 138 minunit = 666; 139 for (ifa = ifap; ifa; ifa = ifa->ifa_next) { 140 if ((ifa->ifa_flags & IFF_UP) == 0) 141 continue; 142 if (ISLOOPBACK(ifa->ifa_name, ifa->ifa_flags)) 143 continue; 144 for (cp = ifa->ifa_name; !isdigit(*cp); ++cp) 145 continue; 146 n = atoi(cp); 147 if (n < minunit) { 148 minunit = n; 149 mp = ifa; 150 } 151 } 152 if (mp == NULL) { 153 (void)strlcpy(errbuf, "no suitable device found", 154 PCAP_ERRBUF_SIZE); 155 freeifaddrs(ifap); 156 return (NULL); 157 } 158 159 (void)strlcpy(device, mp->ifa_name, sizeof(device)); 160 freeifaddrs(ifap); 161 return (device); 162 #else 163 register int fd, minunit, n; 164 register char *cp; 165 register struct ifreq *ifrp, *ifend, *ifnext, *mp; 166 struct ifconf ifc; 167 struct ifreq ibuf[16], ifr; 168 static char device[sizeof(ifrp->ifr_name) + 1]; 169 170 fd = socket(AF_INET, SOCK_DGRAM, 0); 171 if (fd < 0) { 172 (void)snprintf(errbuf, PCAP_ERRBUF_SIZE, "socket: %s", 173 pcap_strerror(errno)); 174 return (NULL); 175 } 176 ifc.ifc_len = sizeof ibuf; 177 ifc.ifc_buf = (caddr_t)ibuf; 178 179 memset((char *)ibuf, 0, sizeof(ibuf)); 180 if (ioctl(fd, SIOCGIFCONF, (char *)&ifc) < 0 || 181 ifc.ifc_len < sizeof(struct ifreq)) { 182 (void)snprintf(errbuf, PCAP_ERRBUF_SIZE, "SIOCGIFCONF: %s", 183 pcap_strerror(errno)); 184 (void)close(fd); 185 return (NULL); 186 } 187 ifrp = ibuf; 188 ifend = (struct ifreq *)((char *)ibuf + ifc.ifc_len); 189 190 mp = NULL; 191 minunit = 666; 192 for (; ifrp < ifend; ifrp = ifnext) { 193 #ifdef HAVE_SOCKADDR_SA_LEN 194 n = ifrp->ifr_addr.sa_len + sizeof(ifrp->ifr_name); 195 if (n < sizeof(*ifrp)) 196 ifnext = ifrp + 1; 197 else 198 ifnext = (struct ifreq *)((char *)ifrp + n); 199 if (ifrp->ifr_addr.sa_family != AF_INET) 200 continue; 201 #else 202 ifnext = ifrp + 1; 203 #endif 204 /* 205 * Need a template to preserve address info that is 206 * used below to locate the next entry. (Otherwise, 207 * SIOCGIFFLAGS stomps over it because the requests 208 * are returned in a union.) 209 */ 210 (void)strlcpy(ifr.ifr_name, ifrp->ifr_name, 211 sizeof(ifr.ifr_name)); 212 if (ioctl(fd, SIOCGIFFLAGS, (char *)&ifr) < 0) { 213 if (errno == ENXIO) 214 continue; 215 (void)snprintf(errbuf, PCAP_ERRBUF_SIZE, 216 "SIOCGIFFLAGS: %.*s: %s", 217 (int)sizeof(ifr.ifr_name), ifr.ifr_name, 218 pcap_strerror(errno)); 219 (void)close(fd); 220 return (NULL); 221 } 222 223 /* Must be up and not the loopback */ 224 if ((ifr.ifr_flags & IFF_UP) == 0 || 225 ISLOOPBACK(ifr.ifr_name, ifr.ifr_flags)) 226 continue; 227 228 for (cp = ifrp->ifr_name; !isdigit(*cp); ++cp) 229 continue; 230 n = atoi(cp); 231 if (n < minunit) { 232 minunit = n; 233 mp = ifrp; 234 } 235 } 236 (void)close(fd); 237 if (mp == NULL) { 238 (void)strlcpy(errbuf, "no suitable device found", 239 PCAP_ERRBUF_SIZE); 240 return (NULL); 241 } 242 243 (void)strlcpy(device, mp->ifr_name, sizeof(device)); 244 return (device); 245 #endif 246 } 247 248 int 249 pcap_lookupnet(const char *device, bpf_u_int32 *netp, bpf_u_int32 *maskp, 250 char *errbuf) 251 { 252 int fd; 253 struct sockaddr_in *sin; 254 struct ifreq ifr; 255 256 fd = socket(AF_INET, SOCK_DGRAM, 0); 257 if (fd < 0) { 258 (void)snprintf(errbuf, PCAP_ERRBUF_SIZE, "socket: %s", 259 pcap_strerror(errno)); 260 return (-1); 261 } 262 memset(&ifr, 0, sizeof(ifr)); 263 #ifdef linux 264 /* XXX Work around Linux kernel bug */ 265 ifr.ifr_addr.sa_family = AF_INET; 266 #endif 267 (void)strlcpy(ifr.ifr_name, device, sizeof(ifr.ifr_name)); 268 if (ioctl(fd, SIOCGIFADDR, (char *)&ifr) < 0) { 269 if (errno == EADDRNOTAVAIL) { 270 (void)snprintf(errbuf, PCAP_ERRBUF_SIZE, 271 "%s: no IPv4 address assigned", device); 272 } else { 273 (void)snprintf(errbuf, PCAP_ERRBUF_SIZE, 274 "SIOCGIFADDR: %s: %s", 275 device, pcap_strerror(errno)); 276 } 277 (void)close(fd); 278 return (-1); 279 } 280 sin = (struct sockaddr_in *)&ifr.ifr_addr; 281 *netp = sin->sin_addr.s_addr; 282 if (ioctl(fd, SIOCGIFNETMASK, (char *)&ifr) < 0) { 283 (void)snprintf(errbuf, PCAP_ERRBUF_SIZE, 284 "SIOCGIFNETMASK: %s: %s", device, pcap_strerror(errno)); 285 (void)close(fd); 286 return (-1); 287 } 288 (void)close(fd); 289 *maskp = sin->sin_addr.s_addr; 290 if (*maskp == 0) { 291 if (IN_CLASSA(*netp)) 292 *maskp = IN_CLASSA_NET; 293 else if (IN_CLASSB(*netp)) 294 *maskp = IN_CLASSB_NET; 295 else if (IN_CLASSC(*netp)) 296 *maskp = IN_CLASSC_NET; 297 else { 298 (void)snprintf(errbuf, PCAP_ERRBUF_SIZE, 299 "inet class for 0x%x unknown", *netp); 300 return (-1); 301 } 302 } 303 *netp &= *maskp; 304 return (0); 305 } 306