1 /* $OpenBSD: inet.c,v 1.22 2015/11/17 18:19:45 mmcc 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/file.h> 38 #include <sys/ioctl.h> 39 #include <sys/socket.h> 40 #ifdef HAVE_SYS_SOCKIO_H 41 #include <sys/sockio.h> 42 #endif 43 #include <sys/time.h> /* concession to AIX */ 44 45 struct mbuf; 46 struct rtentry; 47 48 #include <net/if.h> 49 #include <netinet/in.h> 50 51 #include <ctype.h> 52 #include <errno.h> 53 #include <stdio.h> 54 #include <stdlib.h> 55 #include <string.h> 56 #include <unistd.h> 57 #ifdef HAVE_IFADDRS_H 58 #include <ifaddrs.h> 59 #endif 60 61 #include "pcap-int.h" 62 63 #ifdef HAVE_OS_PROTO_H 64 #include "os-proto.h" 65 #endif 66 67 /* 68 * Free a list of interfaces. 69 */ 70 void 71 pcap_freealldevs(pcap_if_t *alldevs) 72 { 73 pcap_if_t *curdev, *nextdev; 74 pcap_addr_t *curaddr, *nextaddr; 75 76 for (curdev = alldevs; curdev != NULL; curdev = nextdev) { 77 nextdev = curdev->next; 78 79 /* 80 * Free all addresses. 81 */ 82 for (curaddr = curdev->addresses; curaddr != NULL; 83 curaddr = nextaddr) { 84 nextaddr = curaddr->next; 85 if (curaddr->addr) 86 free(curaddr->addr); 87 if (curaddr->netmask) 88 free(curaddr->netmask); 89 if (curaddr->broadaddr) 90 free(curaddr->broadaddr); 91 if (curaddr->dstaddr) 92 free(curaddr->dstaddr); 93 free(curaddr); 94 } 95 96 /* 97 * Free the name string. 98 */ 99 free(curdev->name); 100 101 /* 102 * Free the description string, if any. 103 */ 104 if (curdev->description != NULL) 105 free(curdev->description); 106 107 /* 108 * Free the interface. 109 */ 110 free(curdev); 111 } 112 } 113 114 /* 115 * Return the name of a network interface attached to the system, or NULL 116 * if none can be found. The interface must be configured up; the 117 * lowest unit number is preferred; loopback is ignored. 118 */ 119 char * 120 pcap_lookupdev(errbuf) 121 register char *errbuf; 122 { 123 #ifdef HAVE_IFADDRS_H 124 struct ifaddrs *ifap, *ifa, *mp; 125 int n, minunit; 126 char *cp; 127 static char device[IF_NAMESIZE + 1]; 128 129 if (getifaddrs(&ifap) != 0) { 130 (void)snprintf(errbuf, PCAP_ERRBUF_SIZE, 131 "getifaddrs: %s", pcap_strerror(errno)); 132 return NULL; 133 } 134 135 mp = NULL; 136 minunit = 666; 137 for (ifa = ifap; ifa; ifa = ifa->ifa_next) { 138 if ((ifa->ifa_flags & IFF_UP) == 0) 139 continue; 140 if (ISLOOPBACK(ifa->ifa_name, ifa->ifa_flags)) 141 continue; 142 for (cp = ifa->ifa_name; !isdigit((unsigned char)*cp); ++cp) 143 continue; 144 n = atoi(cp); 145 if (n < minunit) { 146 minunit = n; 147 mp = ifa; 148 } 149 } 150 if (mp == NULL) { 151 (void)strlcpy(errbuf, "no suitable device found", 152 PCAP_ERRBUF_SIZE); 153 freeifaddrs(ifap); 154 return (NULL); 155 } 156 157 (void)strlcpy(device, mp->ifa_name, sizeof(device)); 158 freeifaddrs(ifap); 159 return (device); 160 #else 161 register int fd, minunit, n; 162 register char *cp; 163 register struct ifreq *ifrp, *ifend, *ifnext, *mp; 164 struct ifconf ifc; 165 struct ifreq ibuf[16], ifr; 166 static char device[sizeof(ifrp->ifr_name) + 1]; 167 168 fd = socket(AF_INET, SOCK_DGRAM, 0); 169 if (fd < 0) { 170 (void)snprintf(errbuf, PCAP_ERRBUF_SIZE, "socket: %s", 171 pcap_strerror(errno)); 172 return (NULL); 173 } 174 ifc.ifc_len = sizeof ibuf; 175 ifc.ifc_buf = (caddr_t)ibuf; 176 177 memset((char *)ibuf, 0, sizeof(ibuf)); 178 if (ioctl(fd, SIOCGIFCONF, (char *)&ifc) < 0 || 179 ifc.ifc_len < sizeof(struct ifreq)) { 180 (void)snprintf(errbuf, PCAP_ERRBUF_SIZE, "SIOCGIFCONF: %s", 181 pcap_strerror(errno)); 182 (void)close(fd); 183 return (NULL); 184 } 185 ifrp = ibuf; 186 ifend = (struct ifreq *)((char *)ibuf + ifc.ifc_len); 187 188 mp = NULL; 189 minunit = 666; 190 for (; ifrp < ifend; ifrp = ifnext) { 191 #ifdef HAVE_SOCKADDR_SA_LEN 192 n = ifrp->ifr_addr.sa_len + sizeof(ifrp->ifr_name); 193 if (n < sizeof(*ifrp)) 194 ifnext = ifrp + 1; 195 else 196 ifnext = (struct ifreq *)((char *)ifrp + n); 197 if (ifrp->ifr_addr.sa_family != AF_INET) 198 continue; 199 #else 200 ifnext = ifrp + 1; 201 #endif 202 /* 203 * Need a template to preserve address info that is 204 * used below to locate the next entry. (Otherwise, 205 * SIOCGIFFLAGS stomps over it because the requests 206 * are returned in a union.) 207 */ 208 (void)strlcpy(ifr.ifr_name, ifrp->ifr_name, 209 sizeof(ifr.ifr_name)); 210 if (ioctl(fd, SIOCGIFFLAGS, (char *)&ifr) < 0) { 211 if (errno == ENXIO) 212 continue; 213 (void)snprintf(errbuf, PCAP_ERRBUF_SIZE, 214 "SIOCGIFFLAGS: %.*s: %s", 215 (int)sizeof(ifr.ifr_name), ifr.ifr_name, 216 pcap_strerror(errno)); 217 (void)close(fd); 218 return (NULL); 219 } 220 221 /* Must be up and not the loopback */ 222 if ((ifr.ifr_flags & IFF_UP) == 0 || 223 ISLOOPBACK(ifr.ifr_name, ifr.ifr_flags)) 224 continue; 225 226 for (cp = ifrp->ifr_name; !isdigit((unsigned char)*cp); ++cp) 227 continue; 228 n = atoi(cp); 229 if (n < minunit) { 230 minunit = n; 231 mp = ifrp; 232 } 233 } 234 (void)close(fd); 235 if (mp == NULL) { 236 (void)strlcpy(errbuf, "no suitable device found", 237 PCAP_ERRBUF_SIZE); 238 return (NULL); 239 } 240 241 (void)strlcpy(device, mp->ifr_name, sizeof(device)); 242 return (device); 243 #endif 244 } 245 246 int 247 pcap_lookupnet(const char *device, bpf_u_int32 *netp, bpf_u_int32 *maskp, 248 char *errbuf) 249 { 250 int fd; 251 struct sockaddr_in *sin; 252 struct ifreq ifr; 253 254 fd = socket(AF_INET, SOCK_DGRAM, 0); 255 if (fd < 0) { 256 (void)snprintf(errbuf, PCAP_ERRBUF_SIZE, "socket: %s", 257 pcap_strerror(errno)); 258 return (-1); 259 } 260 memset(&ifr, 0, sizeof(ifr)); 261 #ifdef linux 262 /* XXX Work around Linux kernel bug */ 263 ifr.ifr_addr.sa_family = AF_INET; 264 #endif 265 (void)strlcpy(ifr.ifr_name, device, sizeof(ifr.ifr_name)); 266 if (ioctl(fd, SIOCGIFADDR, (char *)&ifr) < 0) { 267 if (errno == EADDRNOTAVAIL) { 268 (void)snprintf(errbuf, PCAP_ERRBUF_SIZE, 269 "%s: no IPv4 address assigned", device); 270 } else { 271 (void)snprintf(errbuf, PCAP_ERRBUF_SIZE, 272 "SIOCGIFADDR: %s: %s", 273 device, pcap_strerror(errno)); 274 } 275 (void)close(fd); 276 return (-1); 277 } 278 sin = (struct sockaddr_in *)&ifr.ifr_addr; 279 *netp = sin->sin_addr.s_addr; 280 if (ioctl(fd, SIOCGIFNETMASK, (char *)&ifr) < 0) { 281 (void)snprintf(errbuf, PCAP_ERRBUF_SIZE, 282 "SIOCGIFNETMASK: %s: %s", device, pcap_strerror(errno)); 283 (void)close(fd); 284 return (-1); 285 } 286 (void)close(fd); 287 *maskp = sin->sin_addr.s_addr; 288 if (*maskp == 0) { 289 if (IN_CLASSA(*netp)) 290 *maskp = IN_CLASSA_NET; 291 else if (IN_CLASSB(*netp)) 292 *maskp = IN_CLASSB_NET; 293 else if (IN_CLASSC(*netp)) 294 *maskp = IN_CLASSC_NET; 295 else { 296 (void)snprintf(errbuf, PCAP_ERRBUF_SIZE, 297 "inet class for 0x%x unknown", *netp); 298 return (-1); 299 } 300 } 301 *netp &= *maskp; 302 return (0); 303 } 304