1 /* $OpenBSD: inet.c,v 1.25 2019/06/28 13:32:42 deraadt 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 free(curaddr->addr); 86 free(curaddr->netmask); 87 free(curaddr->broadaddr); 88 free(curaddr->dstaddr); 89 free(curaddr); 90 } 91 92 /* 93 * Free the name string. 94 */ 95 free(curdev->name); 96 97 /* 98 * Free the description string, if any. 99 */ 100 free(curdev->description); 101 102 /* 103 * Free the interface. 104 */ 105 free(curdev); 106 } 107 } 108 109 /* 110 * Return the name of a network interface attached to the system, or NULL 111 * if none can be found. The interface must be configured up; the 112 * lowest unit number is preferred; loopback is ignored. 113 */ 114 char * 115 pcap_lookupdev(errbuf) 116 char *errbuf; 117 { 118 #ifdef HAVE_IFADDRS_H 119 struct ifaddrs *ifap, *ifa, *mp; 120 int n, minunit; 121 char *cp; 122 static char device[IF_NAMESIZE + 1]; 123 124 if (getifaddrs(&ifap) != 0) { 125 (void)snprintf(errbuf, PCAP_ERRBUF_SIZE, 126 "getifaddrs: %s", pcap_strerror(errno)); 127 return NULL; 128 } 129 130 mp = NULL; 131 minunit = 666; 132 for (ifa = ifap; ifa; ifa = ifa->ifa_next) { 133 if ((ifa->ifa_flags & IFF_UP) == 0) 134 continue; 135 if (ISLOOPBACK(ifa->ifa_name, ifa->ifa_flags)) 136 continue; 137 for (cp = ifa->ifa_name; !isdigit((unsigned char)*cp); ++cp) 138 continue; 139 n = atoi(cp); 140 if (n < minunit) { 141 minunit = n; 142 mp = ifa; 143 } 144 } 145 if (mp == NULL) { 146 (void)strlcpy(errbuf, "no suitable device found", 147 PCAP_ERRBUF_SIZE); 148 freeifaddrs(ifap); 149 return (NULL); 150 } 151 152 (void)strlcpy(device, mp->ifa_name, sizeof(device)); 153 freeifaddrs(ifap); 154 return (device); 155 #else 156 int fd, minunit, n; 157 char *cp; 158 struct ifreq *ifrp, *ifend, *ifnext, *mp; 159 struct ifconf ifc; 160 struct ifreq ibuf[16], ifr; 161 static char device[sizeof(ifrp->ifr_name) + 1]; 162 163 fd = socket(AF_INET, SOCK_DGRAM, 0); 164 if (fd == -1) { 165 (void)snprintf(errbuf, PCAP_ERRBUF_SIZE, "socket: %s", 166 pcap_strerror(errno)); 167 return (NULL); 168 } 169 ifc.ifc_len = sizeof ibuf; 170 ifc.ifc_buf = (caddr_t)ibuf; 171 172 memset((char *)ibuf, 0, sizeof(ibuf)); 173 if (ioctl(fd, SIOCGIFCONF, (char *)&ifc) == -1 || 174 ifc.ifc_len < sizeof(struct ifreq)) { 175 (void)snprintf(errbuf, PCAP_ERRBUF_SIZE, "SIOCGIFCONF: %s", 176 pcap_strerror(errno)); 177 (void)close(fd); 178 return (NULL); 179 } 180 ifrp = ibuf; 181 ifend = (struct ifreq *)((char *)ibuf + ifc.ifc_len); 182 183 mp = NULL; 184 minunit = 666; 185 for (; ifrp < ifend; ifrp = ifnext) { 186 #ifdef HAVE_SOCKADDR_SA_LEN 187 n = ifrp->ifr_addr.sa_len + sizeof(ifrp->ifr_name); 188 if (n < sizeof(*ifrp)) 189 ifnext = ifrp + 1; 190 else 191 ifnext = (struct ifreq *)((char *)ifrp + n); 192 if (ifrp->ifr_addr.sa_family != AF_INET) 193 continue; 194 #else 195 ifnext = ifrp + 1; 196 #endif 197 /* 198 * Need a template to preserve address info that is 199 * used below to locate the next entry. (Otherwise, 200 * SIOCGIFFLAGS stomps over it because the requests 201 * are returned in a union.) 202 */ 203 (void)strlcpy(ifr.ifr_name, ifrp->ifr_name, 204 sizeof(ifr.ifr_name)); 205 if (ioctl(fd, SIOCGIFFLAGS, (char *)&ifr) == -1) { 206 if (errno == ENXIO) 207 continue; 208 (void)snprintf(errbuf, PCAP_ERRBUF_SIZE, 209 "SIOCGIFFLAGS: %.*s: %s", 210 (int)sizeof(ifr.ifr_name), ifr.ifr_name, 211 pcap_strerror(errno)); 212 (void)close(fd); 213 return (NULL); 214 } 215 216 /* Must be up and not the loopback */ 217 if ((ifr.ifr_flags & IFF_UP) == 0 || 218 ISLOOPBACK(ifr.ifr_name, ifr.ifr_flags)) 219 continue; 220 221 for (cp = ifrp->ifr_name; !isdigit((unsigned char)*cp); ++cp) 222 continue; 223 n = atoi(cp); 224 if (n < minunit) { 225 minunit = n; 226 mp = ifrp; 227 } 228 } 229 (void)close(fd); 230 if (mp == NULL) { 231 (void)strlcpy(errbuf, "no suitable device found", 232 PCAP_ERRBUF_SIZE); 233 return (NULL); 234 } 235 236 (void)strlcpy(device, mp->ifr_name, sizeof(device)); 237 return (device); 238 #endif 239 } 240 241 int 242 pcap_lookupnet(const char *device, bpf_u_int32 *netp, bpf_u_int32 *maskp, 243 char *errbuf) 244 { 245 int fd; 246 struct sockaddr_in *sin; 247 struct ifreq ifr; 248 249 fd = socket(AF_INET, SOCK_DGRAM, 0); 250 if (fd == -1) { 251 (void)snprintf(errbuf, PCAP_ERRBUF_SIZE, "socket: %s", 252 pcap_strerror(errno)); 253 return (-1); 254 } 255 memset(&ifr, 0, sizeof(ifr)); 256 #ifdef linux 257 /* XXX Work around Linux kernel bug */ 258 ifr.ifr_addr.sa_family = AF_INET; 259 #endif 260 (void)strlcpy(ifr.ifr_name, device, sizeof(ifr.ifr_name)); 261 if (ioctl(fd, SIOCGIFADDR, (char *)&ifr) == -1) { 262 if (errno == EADDRNOTAVAIL) { 263 (void)snprintf(errbuf, PCAP_ERRBUF_SIZE, 264 "%s: no IPv4 address assigned", device); 265 } else { 266 (void)snprintf(errbuf, PCAP_ERRBUF_SIZE, 267 "SIOCGIFADDR: %s: %s", 268 device, pcap_strerror(errno)); 269 } 270 (void)close(fd); 271 return (-1); 272 } 273 sin = (struct sockaddr_in *)&ifr.ifr_addr; 274 *netp = sin->sin_addr.s_addr; 275 if (ioctl(fd, SIOCGIFNETMASK, (char *)&ifr) == -1) { 276 (void)snprintf(errbuf, PCAP_ERRBUF_SIZE, 277 "SIOCGIFNETMASK: %s: %s", device, pcap_strerror(errno)); 278 (void)close(fd); 279 return (-1); 280 } 281 (void)close(fd); 282 *maskp = sin->sin_addr.s_addr; 283 if (*maskp == 0) { 284 if (IN_CLASSA(*netp)) 285 *maskp = IN_CLASSA_NET; 286 else if (IN_CLASSB(*netp)) 287 *maskp = IN_CLASSB_NET; 288 else if (IN_CLASSC(*netp)) 289 *maskp = IN_CLASSC_NET; 290 else { 291 (void)snprintf(errbuf, PCAP_ERRBUF_SIZE, 292 "inet class for 0x%x unknown", *netp); 293 return (-1); 294 } 295 } 296 *netp &= *maskp; 297 return (0); 298 } 299