/* $OpenBSD: inet.c,v 1.10 1998/08/27 22:36:33 mickey Exp $ */ /* * Copyright (c) 1994, 1995, 1996 * The Regents of the University of California. All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * 3. All advertising materials mentioning features or use of this software * must display the following acknowledgement: * This product includes software developed by the Computer Systems * Engineering Group at Lawrence Berkeley Laboratory. * 4. Neither the name of the University nor of the Laboratory may be used * to endorse or promote products derived from this software without * specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. */ #ifndef lint static char rcsid[] = "@(#) Header: inet.c,v 1.16 96/06/23 14:28:22 leres Exp (LBL)"; #endif #include #include #include #include #ifdef HAVE_SYS_SOCKIO_H #include #endif #ifdef __STDC__ struct mbuf; struct rtentry; #endif #include #include #include #include #include #include #include #include #include #include #ifdef HAVE_OS_PROTO_H #include "os-proto.h" #endif #include "pcap-int.h" /* Not all systems have IFF_LOOPBACK */ #ifdef IFF_LOOPBACK #define ISLOOPBACK(p) ((p)->ifr_flags & IFF_LOOPBACK) #else #define ISLOOPBACK(p) (strcmp((p)->ifr_name, "lo0") == 0) #endif /* * Return the name of a network interface attached to the system, or NULL * if none can be found. The interface must be configured up; the * lowest unit number is preferred; loopback is ignored. */ char * pcap_lookupdev(errbuf) register char *errbuf; { register int fd, minunit, n; register char *cp, *ibuf = NULL, *nibuf; register struct ifreq *ifrp, *ifend, *ifnext, *mp; struct ifconf ifc; struct ifreq ifr; static char device[sizeof(ifrp->ifr_name) + 1]; int len = 8192; fd = socket(AF_INET, SOCK_DGRAM, 0); if (fd < 0) { (void)snprintf(errbuf, PCAP_ERRBUF_SIZE, "socket: %s", pcap_strerror(errno)); return (NULL); } while (1) { ifc.ifc_len = len; nibuf = realloc(ibuf, len); if (nibuf == NULL) { if (ibuf) free(ibuf); close(fd); return (NULL); } ifc.ifc_buf = ibuf = nibuf; if (ioctl(fd, SIOCGIFCONF, (char *)&ifc) < 0) { (void)close(fd); free(ibuf); return (NULL); } if (ifc.ifc_len + sizeof(ifr) < len) break; len *= 2; } ifrp = (struct ifreq *)ibuf; ifend = (struct ifreq *)((char *)ibuf + ifc.ifc_len); mp = NULL; minunit = 666; for (; ifrp < ifend; ifrp = ifnext) { #if BSD - 0 >= 199006 n = ifrp->ifr_addr.sa_len + sizeof(ifrp->ifr_name); if (n < sizeof(*ifrp)) ifnext = ifrp + 1; else ifnext = (struct ifreq *)((char *)ifrp + n); if (ifrp->ifr_addr.sa_family != AF_INET) continue; #else ifnext = ifrp + 1; #endif /* * Need a template to preserve address info that is * used below to locate the next entry. (Otherwise, * SIOCGIFFLAGS stomps over it because the requests * are returned in a union.) */ strncpy(ifr.ifr_name, ifrp->ifr_name, sizeof(ifr.ifr_name)); if (ioctl(fd, SIOCGIFFLAGS, (char *)&ifr) < 0) { (void)snprintf(errbuf, PCAP_ERRBUF_SIZE, "SIOCGIFFLAGS: %s", pcap_strerror(errno)); (void)close(fd); free(ibuf); return (NULL); } /* Must be up and not the loopback */ if ((ifr.ifr_flags & IFF_UP) == 0 || ISLOOPBACK(&ifr)) continue; for (cp = ifrp->ifr_name; !isdigit(*cp); ++cp) continue; n = atoi(cp); if (n < minunit) { minunit = n; mp = ifrp; } } (void)close(fd); if (mp == NULL) { (void)strcpy(errbuf, "no suitable device found"); free(ibuf); return (NULL); } (void)strncpy(device, mp->ifr_name, sizeof(device) - 1); device[sizeof(device) - 1] = '\0'; free(ibuf); return (device); } int pcap_lookupnet(device, netp, maskp, errbuf) register char *device; register bpf_u_int32 *netp, *maskp; register char *errbuf; { register int fd; register struct sockaddr_in *sin; struct ifreq ifr; fd = socket(AF_INET, SOCK_DGRAM, 0); if (fd < 0) { (void)snprintf(errbuf, PCAP_ERRBUF_SIZE, "socket: %s", pcap_strerror(errno)); return (-1); } memset(&ifr, 0, sizeof(ifr)); #ifdef linux /* XXX Work around Linux kernel bug */ ifr.ifr_addr.sa_family = AF_INET; #endif (void)strncpy(ifr.ifr_name, device, sizeof(ifr.ifr_name)); if (ioctl(fd, SIOCGIFADDR, (char *)&ifr) < 0) { (void)snprintf(errbuf, PCAP_ERRBUF_SIZE, "SIOCGIFADDR: %s: %s", device, pcap_strerror(errno)); (void)close(fd); return (-1); } sin = (struct sockaddr_in *)&ifr.ifr_addr; *netp = sin->sin_addr.s_addr; if (ioctl(fd, SIOCGIFNETMASK, (char *)&ifr) < 0) { (void)snprintf(errbuf, PCAP_ERRBUF_SIZE, "SIOCGIFNETMASK: %s: %s", device, pcap_strerror(errno)); (void)close(fd); return (-1); } (void)close(fd); *maskp = sin->sin_addr.s_addr; if (*maskp == 0) { if (IN_CLASSA(*netp)) *maskp = IN_CLASSA_NET; else if (IN_CLASSB(*netp)) *maskp = IN_CLASSB_NET; else if (IN_CLASSC(*netp)) *maskp = IN_CLASSC_NET; else { (void)snprintf(errbuf, PCAP_ERRBUF_SIZE, "inet class for 0x%x unknown", *netp); return (-1); } } *netp &= *maskp; return (0); }