inet.c revision 1.16
1/* $OpenBSD: inet.c,v 1.16 2004/01/27 06:58:03 tedu 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 46struct mbuf; 47struct 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/* Not all systems have IFF_LOOPBACK */ 70#ifdef IFF_LOOPBACK 71#define ISLOOPBACK(p) ((p)->ifr_flags & IFF_LOOPBACK) 72#else 73#define ISLOOPBACK(p) ((p)->ifr_name[0] == 'l' && (p)->ifr_name[1] == 'o' && \ 74 (isdigit((p)->ifr_name[2]) || (p)->ifr_name[2] == '\0')) 75#endif 76 77/* 78 * Return the name of a network interface attached to the system, or NULL 79 * if none can be found. The interface must be configured up; the 80 * lowest unit number is preferred; loopback is ignored. 81 */ 82char * 83pcap_lookupdev(errbuf) 84 register char *errbuf; 85{ 86#ifdef HAVE_IFADDRS_H 87 struct ifaddrs *ifap, *ifa, *mp; 88 int n, minunit; 89 char *cp; 90 static char device[IF_NAMESIZE + 1]; 91 92 if (getifaddrs(&ifap) != 0) { 93 (void)snprintf(errbuf, PCAP_ERRBUF_SIZE, 94 "getifaddrs: %s", pcap_strerror(errno)); 95 return NULL; 96 } 97 98 mp = NULL; 99 minunit = 666; 100 for (ifa = ifap; ifa; ifa = ifa->ifa_next) { 101 if ((ifa->ifa_flags & IFF_UP) == 0) 102 continue; 103#ifdef IFF_LOOPBACK 104 if ((ifa->ifa_flags & IFF_LOOPBACK) != 0) 105 continue; 106#else 107 if (strncmp(ifa->ifa_name, "lo", 2) == 0 && 108 (ifa->ifa_name[2] == '\0' || isdigit(ifa->ifa_name[2]))) { 109 continue; 110 } 111#endif 112 113 for (cp = ifa->ifa_name; !isdigit(*cp); ++cp) 114 continue; 115 n = atoi(cp); 116 if (n < minunit) { 117 minunit = n; 118 mp = ifa; 119 } 120 } 121 if (mp == NULL) { 122 (void)strlcpy(errbuf, "no suitable device found", 123 PCAP_ERRBUF_SIZE); 124 freeifaddrs(ifap); 125 return (NULL); 126 } 127 128 (void)strlcpy(device, mp->ifa_name, sizeof(device)); 129 freeifaddrs(ifap); 130 return (device); 131#else 132 register int fd, minunit, n; 133 register char *cp; 134 register struct ifreq *ifrp, *ifend, *ifnext, *mp; 135 struct ifconf ifc; 136 struct ifreq ibuf[16], ifr; 137 static char device[sizeof(ifrp->ifr_name) + 1]; 138 139 fd = socket(AF_INET, SOCK_DGRAM, 0); 140 if (fd < 0) { 141 (void)snprintf(errbuf, PCAP_ERRBUF_SIZE, "socket: %s", 142 pcap_strerror(errno)); 143 return (NULL); 144 } 145 ifc.ifc_len = sizeof ibuf; 146 ifc.ifc_buf = (caddr_t)ibuf; 147 148 memset((char *)ibuf, 0, sizeof(ibuf)); 149 if (ioctl(fd, SIOCGIFCONF, (char *)&ifc) < 0 || 150 ifc.ifc_len < sizeof(struct ifreq)) { 151 (void)snprintf(errbuf, PCAP_ERRBUF_SIZE, "SIOCGIFCONF: %s", 152 pcap_strerror(errno)); 153 (void)close(fd); 154 return (NULL); 155 } 156 ifrp = ibuf; 157 ifend = (struct ifreq *)((char *)ibuf + ifc.ifc_len); 158 159 mp = NULL; 160 minunit = 666; 161 for (; ifrp < ifend; ifrp = ifnext) { 162#ifdef HAVE_SOCKADDR_SA_LEN 163 n = ifrp->ifr_addr.sa_len + sizeof(ifrp->ifr_name); 164 if (n < sizeof(*ifrp)) 165 ifnext = ifrp + 1; 166 else 167 ifnext = (struct ifreq *)((char *)ifrp + n); 168 if (ifrp->ifr_addr.sa_family != AF_INET) 169 continue; 170#else 171 ifnext = ifrp + 1; 172#endif 173 /* 174 * Need a template to preserve address info that is 175 * used below to locate the next entry. (Otherwise, 176 * SIOCGIFFLAGS stomps over it because the requests 177 * are returned in a union.) 178 */ 179 (void)strlcpy(ifr.ifr_name, ifrp->ifr_name, 180 sizeof(ifr.ifr_name)); 181 if (ioctl(fd, SIOCGIFFLAGS, (char *)&ifr) < 0) { 182 if (errno == ENXIO) 183 continue; 184 (void)snprintf(errbuf, PCAP_ERRBUF_SIZE, 185 "SIOCGIFFLAGS: %.*s: %s", 186 (int)sizeof(ifr.ifr_name), ifr.ifr_name, 187 pcap_strerror(errno)); 188 (void)close(fd); 189 return (NULL); 190 } 191 192 /* Must be up and not the loopback */ 193 if ((ifr.ifr_flags & IFF_UP) == 0 || ISLOOPBACK(&ifr)) 194 continue; 195 196 for (cp = ifrp->ifr_name; !isdigit(*cp); ++cp) 197 continue; 198 n = atoi(cp); 199 if (n < minunit) { 200 minunit = n; 201 mp = ifrp; 202 } 203 } 204 (void)close(fd); 205 if (mp == NULL) { 206 (void)strlcpy(errbuf, "no suitable device found", 207 PCAP_ERRBUF_SIZE); 208 return (NULL); 209 } 210 211 (void)strlcpy(device, mp->ifr_name, sizeof(device)); 212 return (device); 213#endif 214} 215 216int 217pcap_lookupnet(device, netp, maskp, errbuf) 218 register char *device; 219 register bpf_u_int32 *netp, *maskp; 220 register char *errbuf; 221{ 222 register int fd; 223 register struct sockaddr_in *sin; 224 struct ifreq ifr; 225 226 fd = socket(AF_INET, SOCK_DGRAM, 0); 227 if (fd < 0) { 228 (void)snprintf(errbuf, PCAP_ERRBUF_SIZE, "socket: %s", 229 pcap_strerror(errno)); 230 return (-1); 231 } 232 memset(&ifr, 0, sizeof(ifr)); 233#ifdef linux 234 /* XXX Work around Linux kernel bug */ 235 ifr.ifr_addr.sa_family = AF_INET; 236#endif 237 (void)strlcpy(ifr.ifr_name, device, sizeof(ifr.ifr_name)); 238 if (ioctl(fd, SIOCGIFADDR, (char *)&ifr) < 0) { 239 if (errno == EADDRNOTAVAIL) { 240 (void)snprintf(errbuf, PCAP_ERRBUF_SIZE, 241 "%s: no IPv4 address assigned", device); 242 } else { 243 (void)snprintf(errbuf, PCAP_ERRBUF_SIZE, 244 "SIOCGIFADDR: %s: %s", 245 device, pcap_strerror(errno)); 246 } 247 (void)close(fd); 248 return (-1); 249 } 250 sin = (struct sockaddr_in *)&ifr.ifr_addr; 251 *netp = sin->sin_addr.s_addr; 252 if (ioctl(fd, SIOCGIFNETMASK, (char *)&ifr) < 0) { 253 (void)snprintf(errbuf, PCAP_ERRBUF_SIZE, 254 "SIOCGIFNETMASK: %s: %s", device, pcap_strerror(errno)); 255 (void)close(fd); 256 return (-1); 257 } 258 (void)close(fd); 259 *maskp = sin->sin_addr.s_addr; 260 if (*maskp == 0) { 261 if (IN_CLASSA(*netp)) 262 *maskp = IN_CLASSA_NET; 263 else if (IN_CLASSB(*netp)) 264 *maskp = IN_CLASSB_NET; 265 else if (IN_CLASSC(*netp)) 266 *maskp = IN_CLASSC_NET; 267 else { 268 (void)snprintf(errbuf, PCAP_ERRBUF_SIZE, 269 "inet class for 0x%x unknown", *netp); 270 return (-1); 271 } 272 } 273 *netp &= *maskp; 274 return (0); 275} 276