1 /* $OpenBSD: inet.c,v 1.27 2024/04/05 18:01:56 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 #include <net/if.h> 46 #include <netinet/in.h> 47 48 #include <ctype.h> 49 #include <errno.h> 50 #include <stdio.h> 51 #include <stdlib.h> 52 #include <string.h> 53 #include <unistd.h> 54 #ifdef HAVE_IFADDRS_H 55 #include <ifaddrs.h> 56 #endif 57 58 #include "pcap-int.h" 59 60 #ifdef HAVE_OS_PROTO_H 61 #include "os-proto.h" 62 #endif 63 64 /* 65 * Free a list of interfaces. 66 */ 67 void 68 pcap_freealldevs(pcap_if_t *alldevs) 69 { 70 pcap_if_t *curdev, *nextdev; 71 pcap_addr_t *curaddr, *nextaddr; 72 73 for (curdev = alldevs; curdev != NULL; curdev = nextdev) { 74 nextdev = curdev->next; 75 76 /* 77 * Free all addresses. 78 */ 79 for (curaddr = curdev->addresses; curaddr != NULL; 80 curaddr = nextaddr) { 81 nextaddr = curaddr->next; 82 free(curaddr->addr); 83 free(curaddr->netmask); 84 free(curaddr->broadaddr); 85 free(curaddr->dstaddr); 86 free(curaddr); 87 } 88 89 /* 90 * Free the name string. 91 */ 92 free(curdev->name); 93 94 /* 95 * Free the description string, if any. 96 */ 97 free(curdev->description); 98 99 /* 100 * Free the interface. 101 */ 102 free(curdev); 103 } 104 } 105 106 /* 107 * Return the name of a network interface attached to the system, or NULL 108 * if none can be found. The interface must be configured up; the 109 * lowest unit number is preferred; loopback is ignored. 110 */ 111 char * 112 pcap_lookupdev(char *errbuf) 113 { 114 #ifdef HAVE_IFADDRS_H 115 struct ifaddrs *ifap, *ifa, *mp; 116 int n, minunit; 117 char *cp; 118 static char device[IF_NAMESIZE + 1]; 119 120 if (getifaddrs(&ifap) != 0) { 121 (void)snprintf(errbuf, PCAP_ERRBUF_SIZE, 122 "getifaddrs: %s", pcap_strerror(errno)); 123 return NULL; 124 } 125 126 mp = NULL; 127 minunit = 666; 128 for (ifa = ifap; ifa; ifa = ifa->ifa_next) { 129 if ((ifa->ifa_flags & IFF_UP) == 0) 130 continue; 131 if (ISLOOPBACK(ifa->ifa_name, ifa->ifa_flags)) 132 continue; 133 for (cp = ifa->ifa_name; !isdigit((unsigned char)*cp); ++cp) 134 continue; 135 n = atoi(cp); 136 if (n < minunit) { 137 minunit = n; 138 mp = ifa; 139 } 140 } 141 if (mp == NULL) { 142 (void)strlcpy(errbuf, "no suitable device found", 143 PCAP_ERRBUF_SIZE); 144 freeifaddrs(ifap); 145 return (NULL); 146 } 147 148 (void)strlcpy(device, mp->ifa_name, sizeof(device)); 149 freeifaddrs(ifap); 150 return (device); 151 #else 152 int fd, minunit, n; 153 char *cp; 154 struct ifreq *ifrp, *ifend, *ifnext, *mp; 155 struct ifconf ifc; 156 struct ifreq ibuf[16], ifr; 157 static char device[sizeof(ifrp->ifr_name) + 1]; 158 159 fd = socket(AF_INET, SOCK_DGRAM, 0); 160 if (fd == -1) { 161 (void)snprintf(errbuf, PCAP_ERRBUF_SIZE, "socket: %s", 162 pcap_strerror(errno)); 163 return (NULL); 164 } 165 ifc.ifc_len = sizeof ibuf; 166 ifc.ifc_buf = (caddr_t)ibuf; 167 168 memset((char *)ibuf, 0, sizeof(ibuf)); 169 if (ioctl(fd, SIOCGIFCONF, (char *)&ifc) == -1 || 170 ifc.ifc_len < sizeof(struct ifreq)) { 171 (void)snprintf(errbuf, PCAP_ERRBUF_SIZE, "SIOCGIFCONF: %s", 172 pcap_strerror(errno)); 173 (void)close(fd); 174 return (NULL); 175 } 176 ifrp = ibuf; 177 ifend = (struct ifreq *)((char *)ibuf + ifc.ifc_len); 178 179 mp = NULL; 180 minunit = 666; 181 for (; ifrp < ifend; ifrp = ifnext) { 182 #ifdef HAVE_SOCKADDR_SA_LEN 183 n = ifrp->ifr_addr.sa_len + sizeof(ifrp->ifr_name); 184 if (n < sizeof(*ifrp)) 185 ifnext = ifrp + 1; 186 else 187 ifnext = (struct ifreq *)((char *)ifrp + n); 188 if (ifrp->ifr_addr.sa_family != AF_INET) 189 continue; 190 #else 191 ifnext = ifrp + 1; 192 #endif 193 /* 194 * Need a template to preserve address info that is 195 * used below to locate the next entry. (Otherwise, 196 * SIOCGIFFLAGS stomps over it because the requests 197 * are returned in a union.) 198 */ 199 (void)strlcpy(ifr.ifr_name, ifrp->ifr_name, 200 sizeof(ifr.ifr_name)); 201 if (ioctl(fd, SIOCGIFFLAGS, (char *)&ifr) == -1) { 202 if (errno == ENXIO) 203 continue; 204 (void)snprintf(errbuf, PCAP_ERRBUF_SIZE, 205 "SIOCGIFFLAGS: %.*s: %s", 206 (int)sizeof(ifr.ifr_name), ifr.ifr_name, 207 pcap_strerror(errno)); 208 (void)close(fd); 209 return (NULL); 210 } 211 212 /* Must be up and not the loopback */ 213 if ((ifr.ifr_flags & IFF_UP) == 0 || 214 ISLOOPBACK(ifr.ifr_name, ifr.ifr_flags)) 215 continue; 216 217 for (cp = ifrp->ifr_name; !isdigit((unsigned char)*cp); ++cp) 218 continue; 219 n = atoi(cp); 220 if (n < minunit) { 221 minunit = n; 222 mp = ifrp; 223 } 224 } 225 (void)close(fd); 226 if (mp == NULL) { 227 (void)strlcpy(errbuf, "no suitable device found", 228 PCAP_ERRBUF_SIZE); 229 return (NULL); 230 } 231 232 (void)strlcpy(device, mp->ifr_name, sizeof(device)); 233 return (device); 234 #endif 235 } 236 237 int 238 pcap_lookupnet(const char *device, bpf_u_int32 *netp, bpf_u_int32 *maskp, 239 char *errbuf) 240 { 241 int fd; 242 struct sockaddr_in *sin; 243 struct ifreq ifr; 244 245 fd = socket(AF_INET, SOCK_DGRAM, 0); 246 if (fd == -1) { 247 (void)snprintf(errbuf, PCAP_ERRBUF_SIZE, "socket: %s", 248 pcap_strerror(errno)); 249 return (-1); 250 } 251 memset(&ifr, 0, sizeof(ifr)); 252 #ifdef linux 253 /* XXX Work around Linux kernel bug */ 254 ifr.ifr_addr.sa_family = AF_INET; 255 #endif 256 (void)strlcpy(ifr.ifr_name, device, sizeof(ifr.ifr_name)); 257 if (ioctl(fd, SIOCGIFADDR, (char *)&ifr) == -1) { 258 if (errno == EADDRNOTAVAIL) { 259 (void)snprintf(errbuf, PCAP_ERRBUF_SIZE, 260 "%s: no IPv4 address assigned", device); 261 } else { 262 (void)snprintf(errbuf, PCAP_ERRBUF_SIZE, 263 "SIOCGIFADDR: %s: %s", 264 device, pcap_strerror(errno)); 265 } 266 (void)close(fd); 267 return (-1); 268 } 269 sin = (struct sockaddr_in *)&ifr.ifr_addr; 270 *netp = sin->sin_addr.s_addr; 271 if (ioctl(fd, SIOCGIFNETMASK, (char *)&ifr) == -1) { 272 (void)snprintf(errbuf, PCAP_ERRBUF_SIZE, 273 "SIOCGIFNETMASK: %s: %s", device, pcap_strerror(errno)); 274 (void)close(fd); 275 return (-1); 276 } 277 (void)close(fd); 278 *maskp = sin->sin_addr.s_addr; 279 if (*maskp == 0) { 280 if (IN_CLASSA(*netp)) 281 *maskp = IN_CLASSA_NET; 282 else if (IN_CLASSB(*netp)) 283 *maskp = IN_CLASSB_NET; 284 else if (IN_CLASSC(*netp)) 285 *maskp = IN_CLASSC_NET; 286 else { 287 (void)snprintf(errbuf, PCAP_ERRBUF_SIZE, 288 "inet class for 0x%x unknown", *netp); 289 return (-1); 290 } 291 } 292 *netp &= *maskp; 293 return (0); 294 } 295