1 /* $OpenBSD: inet.c,v 1.28 2024/08/28 11:41:42 op 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 <limits.h> 51 #include <stdio.h> 52 #include <stdlib.h> 53 #include <string.h> 54 #include <unistd.h> 55 #ifdef HAVE_IFADDRS_H 56 #include <ifaddrs.h> 57 #endif 58 59 #include "pcap-int.h" 60 61 #ifdef HAVE_OS_PROTO_H 62 #include "os-proto.h" 63 #endif 64 65 /* 66 * Free a list of interfaces. 67 */ 68 void 69 pcap_freealldevs(pcap_if_t *alldevs) 70 { 71 pcap_if_t *curdev, *nextdev; 72 pcap_addr_t *curaddr, *nextaddr; 73 74 for (curdev = alldevs; curdev != NULL; curdev = nextdev) { 75 nextdev = curdev->next; 76 77 /* 78 * Free all addresses. 79 */ 80 for (curaddr = curdev->addresses; curaddr != NULL; 81 curaddr = nextaddr) { 82 nextaddr = curaddr->next; 83 free(curaddr->addr); 84 free(curaddr->netmask); 85 free(curaddr->broadaddr); 86 free(curaddr->dstaddr); 87 free(curaddr); 88 } 89 90 /* 91 * Free the name string. 92 */ 93 free(curdev->name); 94 95 /* 96 * Free the description string, if any. 97 */ 98 free(curdev->description); 99 100 /* 101 * Free the interface. 102 */ 103 free(curdev); 104 } 105 } 106 107 /* 108 * Return the name of a network interface attached to the system, or NULL 109 * if none can be found. The interface must be configured up; the 110 * lowest unit number is preferred; loopback is ignored. 111 */ 112 char * 113 pcap_lookupdev(char *errbuf) 114 { 115 #ifdef HAVE_IFADDRS_H 116 struct ifaddrs *ifap, *ifa, *mp; 117 int n, minunit; 118 char *cp; 119 const char *errstr; 120 static char device[IF_NAMESIZE + 1]; 121 122 if (getifaddrs(&ifap) != 0) { 123 (void)snprintf(errbuf, PCAP_ERRBUF_SIZE, 124 "getifaddrs: %s", pcap_strerror(errno)); 125 return NULL; 126 } 127 128 mp = NULL; 129 minunit = 666; 130 for (ifa = ifap; ifa; ifa = ifa->ifa_next) { 131 if ((ifa->ifa_flags & IFF_UP) == 0) 132 continue; 133 if (ISLOOPBACK(ifa->ifa_name, ifa->ifa_flags)) 134 continue; 135 for (cp = ifa->ifa_name; !isdigit((unsigned char)*cp); ++cp) 136 continue; 137 n = strtonum(cp, 0, INT_MAX, &errstr); 138 if (errstr != NULL) 139 continue; 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 const char *errstr; 159 struct ifreq *ifrp, *ifend, *ifnext, *mp; 160 struct ifconf ifc; 161 struct ifreq ibuf[16], ifr; 162 static char device[sizeof(ifrp->ifr_name) + 1]; 163 164 fd = socket(AF_INET, SOCK_DGRAM, 0); 165 if (fd == -1) { 166 (void)snprintf(errbuf, PCAP_ERRBUF_SIZE, "socket: %s", 167 pcap_strerror(errno)); 168 return (NULL); 169 } 170 ifc.ifc_len = sizeof ibuf; 171 ifc.ifc_buf = (caddr_t)ibuf; 172 173 memset((char *)ibuf, 0, sizeof(ibuf)); 174 if (ioctl(fd, SIOCGIFCONF, (char *)&ifc) == -1 || 175 ifc.ifc_len < sizeof(struct ifreq)) { 176 (void)snprintf(errbuf, PCAP_ERRBUF_SIZE, "SIOCGIFCONF: %s", 177 pcap_strerror(errno)); 178 (void)close(fd); 179 return (NULL); 180 } 181 ifrp = ibuf; 182 ifend = (struct ifreq *)((char *)ibuf + ifc.ifc_len); 183 184 mp = NULL; 185 minunit = 666; 186 for (; ifrp < ifend; ifrp = ifnext) { 187 #ifdef HAVE_SOCKADDR_SA_LEN 188 n = ifrp->ifr_addr.sa_len + sizeof(ifrp->ifr_name); 189 if (n < sizeof(*ifrp)) 190 ifnext = ifrp + 1; 191 else 192 ifnext = (struct ifreq *)((char *)ifrp + n); 193 if (ifrp->ifr_addr.sa_family != AF_INET) 194 continue; 195 #else 196 ifnext = ifrp + 1; 197 #endif 198 /* 199 * Need a template to preserve address info that is 200 * used below to locate the next entry. (Otherwise, 201 * SIOCGIFFLAGS stomps over it because the requests 202 * are returned in a union.) 203 */ 204 (void)strlcpy(ifr.ifr_name, ifrp->ifr_name, 205 sizeof(ifr.ifr_name)); 206 if (ioctl(fd, SIOCGIFFLAGS, (char *)&ifr) == -1) { 207 if (errno == ENXIO) 208 continue; 209 (void)snprintf(errbuf, PCAP_ERRBUF_SIZE, 210 "SIOCGIFFLAGS: %.*s: %s", 211 (int)sizeof(ifr.ifr_name), ifr.ifr_name, 212 pcap_strerror(errno)); 213 (void)close(fd); 214 return (NULL); 215 } 216 217 /* Must be up and not the loopback */ 218 if ((ifr.ifr_flags & IFF_UP) == 0 || 219 ISLOOPBACK(ifr.ifr_name, ifr.ifr_flags)) 220 continue; 221 222 for (cp = ifrp->ifr_name; !isdigit((unsigned char)*cp); ++cp) 223 continue; 224 n = strtonum(cp, 0, INT_MAX, &errstr); 225 if (errstr != NULL) 226 continue; 227 if (n < minunit) { 228 minunit = n; 229 mp = ifrp; 230 } 231 } 232 (void)close(fd); 233 if (mp == NULL) { 234 (void)strlcpy(errbuf, "no suitable device found", 235 PCAP_ERRBUF_SIZE); 236 return (NULL); 237 } 238 239 (void)strlcpy(device, mp->ifr_name, sizeof(device)); 240 return (device); 241 #endif 242 } 243 244 int 245 pcap_lookupnet(const char *device, bpf_u_int32 *netp, bpf_u_int32 *maskp, 246 char *errbuf) 247 { 248 int fd; 249 struct sockaddr_in *sin; 250 struct ifreq ifr; 251 252 fd = socket(AF_INET, SOCK_DGRAM, 0); 253 if (fd == -1) { 254 (void)snprintf(errbuf, PCAP_ERRBUF_SIZE, "socket: %s", 255 pcap_strerror(errno)); 256 return (-1); 257 } 258 memset(&ifr, 0, sizeof(ifr)); 259 #ifdef linux 260 /* XXX Work around Linux kernel bug */ 261 ifr.ifr_addr.sa_family = AF_INET; 262 #endif 263 (void)strlcpy(ifr.ifr_name, device, sizeof(ifr.ifr_name)); 264 if (ioctl(fd, SIOCGIFADDR, (char *)&ifr) == -1) { 265 if (errno == EADDRNOTAVAIL) { 266 (void)snprintf(errbuf, PCAP_ERRBUF_SIZE, 267 "%s: no IPv4 address assigned", device); 268 } else { 269 (void)snprintf(errbuf, PCAP_ERRBUF_SIZE, 270 "SIOCGIFADDR: %s: %s", 271 device, pcap_strerror(errno)); 272 } 273 (void)close(fd); 274 return (-1); 275 } 276 sin = (struct sockaddr_in *)&ifr.ifr_addr; 277 *netp = sin->sin_addr.s_addr; 278 if (ioctl(fd, SIOCGIFNETMASK, (char *)&ifr) == -1) { 279 (void)snprintf(errbuf, PCAP_ERRBUF_SIZE, 280 "SIOCGIFNETMASK: %s: %s", device, pcap_strerror(errno)); 281 (void)close(fd); 282 return (-1); 283 } 284 (void)close(fd); 285 *maskp = sin->sin_addr.s_addr; 286 if (*maskp == 0) { 287 if (IN_CLASSA(*netp)) 288 *maskp = IN_CLASSA_NET; 289 else if (IN_CLASSB(*netp)) 290 *maskp = IN_CLASSB_NET; 291 else if (IN_CLASSC(*netp)) 292 *maskp = IN_CLASSC_NET; 293 else { 294 (void)snprintf(errbuf, PCAP_ERRBUF_SIZE, 295 "inet class for 0x%x unknown", *netp); 296 return (-1); 297 } 298 } 299 *netp &= *maskp; 300 return (0); 301 } 302