/* -*- Mode: c; tab-width: 8; indent-tabs-mode: 1; c-basic-offset: 8; -*- */ /* * Copyright (c) 1994, 1995, 1996, 1997, 1998 * 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 const char rcsid[] = "@(#) $Header: /tcpdump/master/libpcap/inet.c,v 1.46 2002-04-09 07:37:59 guy Exp $ (LBL)"; #endif #ifdef HAVE_CONFIG_H #include "config.h" #endif #include #include #include #include #ifdef HAVE_SYS_SOCKIO_H #include #endif #include /* concession to AIX */ struct mbuf; /* Squelch compiler warnings on some platforms for */ struct rtentry; /* declarations in */ #include #include #include #include #include #include #include #include #include #ifdef HAVE_LIMITS_H #include #else #define INT_MAX 2147483647 #endif #ifdef HAVE_IFADDRS_H #include #endif #include "pcap-int.h" #ifdef HAVE_OS_PROTO_H #include "os-proto.h" #endif /* Not all systems have IFF_LOOPBACK */ #ifdef IFF_LOOPBACK #define ISLOOPBACK(name, flags) ((flags) & IFF_LOOPBACK) #else #define ISLOOPBACK(name, flags) ((name)[0] == 'l' && (name)[1] == 'o' && \ (isdigit((unsigned char)((name)[2])) || (name)[2] == '\0')) #endif /* * This is fun. * * In older BSD systems, socket addresses were fixed-length, and * "sizeof (struct sockaddr)" gave the size of the structure. * All addresses fit within a "struct sockaddr". * * In newer BSD systems, the socket address is variable-length, and * there's an "sa_len" field giving the length of the structure; * this allows socket addresses to be longer than 2 bytes of family * and 14 bytes of data. * * Some commercial UNIXes use the old BSD scheme, and some might use * the new BSD scheme. * * GNU libc uses neither scheme, but has an "SA_LEN()" macro that * determines the size based on the address family. */ #ifndef SA_LEN #ifdef HAVE_SOCKADDR_SA_LEN #define SA_LEN(addr) ((addr)->sa_len) #else /* HAVE_SOCKADDR_SA_LEN */ #define SA_LEN(addr) (sizeof (struct sockaddr)) #endif /* HAVE_SOCKADDR_SA_LEN */ #endif /* SA_LEN */ /* * Description string for the "any" device. */ static const char any_descr[] = "Pseudo-device that captures on all interfaces"; static struct sockaddr * dup_sockaddr(struct sockaddr *sa) { struct sockaddr *newsa; unsigned int size; size = SA_LEN(sa); if ((newsa = malloc(size)) == NULL) return (NULL); return (memcpy(newsa, sa, size)); } static int get_instance(char *name) { char *cp, *endcp; int n; if (strcmp(name, "any") == 0) { /* * Give the "any" device an artificially high instance * number, so it shows up after all other non-loopback * interfaces. */ return INT_MAX; } endcp = name + strlen(name); for (cp = name; cp < endcp && !isdigit((unsigned char)*cp); ++cp) continue; if (isdigit((unsigned char)*cp)) n = atoi(cp); else n = 0; return (n); } static int add_or_find_if(pcap_if_t **curdev_ret, pcap_if_t **alldevs, char *name, u_int flags, const char *description, char *errbuf) { pcap_t *p; pcap_if_t *curdev, *prevdev, *nextdev; int this_instance; /* * Can we open this interface for live capture? */ p = pcap_open_live(name, 68, 0, 0, errbuf); if (p == NULL) { /* * No. Don't bother including it. * Don't treat this as an error, though. */ *curdev_ret = NULL; return (0); } pcap_close(p); /* * Is there already an entry in the list for this interface? */ for (curdev = *alldevs; curdev != NULL; curdev = curdev->next) { if (strcmp(name, curdev->name) == 0) break; /* yes, we found it */ } if (curdev == NULL) { /* * No, we didn't find it. * Allocate a new entry. */ curdev = malloc(sizeof(pcap_if_t)); if (curdev == NULL) { (void)snprintf(errbuf, PCAP_ERRBUF_SIZE, "malloc: %s", pcap_strerror(errno)); return (-1); } /* * Fill in the entry. */ curdev->next = NULL; curdev->name = malloc(strlen(name) + 1); strcpy(curdev->name, name); if (description != NULL) { /* * We have a description for this interface. */ curdev->description = malloc(strlen(description) + 1); strcpy(curdev->description, description); } else { /* * We don't. */ curdev->description = NULL; } curdev->addresses = NULL; /* list starts out as empty */ curdev->flags = 0; if (ISLOOPBACK(name, flags)) curdev->flags |= PCAP_IF_LOOPBACK; /* * Add it to the list, in the appropriate location. * First, get the instance number of this interface. */ this_instance = get_instance(name); /* * Now look for the last interface with an instance number * less than or equal to the new interface's instance * number - except that non-loopback interfaces are * arbitrarily treated as having interface numbers less * than those of loopback interfaces, so the loopback * interfaces are put at the end of the list. * * We start with "prevdev" being NULL, meaning we're before * the first element in the list. */ prevdev = NULL; for (;;) { /* * Get the interface after this one. */ if (prevdev == NULL) { /* * The next element is the first element. */ nextdev = *alldevs; } else nextdev = prevdev->next; /* * Are we at the end of the list? */ if (nextdev == NULL) { /* * Yes - we have to put the new entry * after "prevdev". */ break; } /* * Is the new interface a non-loopback interface * and the next interface a loopback interface? */ if (!(curdev->flags & PCAP_IF_LOOPBACK) && (nextdev->flags & PCAP_IF_LOOPBACK)) { /* * Yes, we should put the new entry * before "nextdev", i.e. after "prevdev". */ break; } /* * Is the new interface's instance number less * than the next interface's instance number, * and is it the case that the new interface is a * non-loopback interface or the next interface is * a loopback interface? * * (The goal of both loopback tests is to make * sure that we never put a loopback interface * before any non-loopback interface and that we * always put a non-loopback interface before all * loopback interfaces.) */ if (this_instance < get_instance(nextdev->name) && (!(curdev->flags & PCAP_IF_LOOPBACK) || (nextdev->flags & PCAP_IF_LOOPBACK))) { /* * Yes - we should put the new entry * before "nextdev", i.e. after "prevdev". */ break; } prevdev = nextdev; } /* * Insert before "nextdev". */ curdev->next = nextdev; /* * Insert after "prevdev" - unless "prevdev" is null, * in which case this is the first interface. */ if (prevdev == NULL) { /* * This is the first interface. Pass back a * pointer to it, and put "curdev" before * "nextdev". */ *alldevs = curdev; } else prevdev->next = curdev; } *curdev_ret = curdev; return (0); } static int add_addr_to_iflist(pcap_if_t **alldevs, char *name, u_int flags, struct sockaddr *addr, struct sockaddr *netmask, struct sockaddr *broadaddr, struct sockaddr *dstaddr, char *errbuf) { pcap_if_t *curdev; pcap_addr_t *curaddr, *prevaddr, *nextaddr; if (add_or_find_if(&curdev, alldevs, name, flags, NULL, errbuf) == -1) { /* * Error - give up. */ return (-1); } if (curdev == NULL) { /* * Device wasn't added because it can't be opened. * Not a fatal error. */ return (0); } /* * "curdev" is an entry for this interface; add an entry for this * address to its list of addresses. * * Allocate the new entry and fill it in. */ curaddr = malloc(sizeof(pcap_addr_t)); if (curaddr == NULL) { (void)snprintf(errbuf, PCAP_ERRBUF_SIZE, "malloc: %s", pcap_strerror(errno)); return (-1); } curaddr->next = NULL; if (addr != NULL) { curaddr->addr = dup_sockaddr(addr); if (curaddr->addr == NULL) { (void)snprintf(errbuf, PCAP_ERRBUF_SIZE, "malloc: %s", pcap_strerror(errno)); free(curaddr); return (-1); } } else curaddr->addr = NULL; if (netmask != NULL) { curaddr->netmask = dup_sockaddr(netmask); if (curaddr->netmask == NULL) { (void)snprintf(errbuf, PCAP_ERRBUF_SIZE, "malloc: %s", pcap_strerror(errno)); free(curaddr); return (-1); } } else curaddr->netmask = NULL; if (broadaddr != NULL) { curaddr->broadaddr = dup_sockaddr(broadaddr); if (curaddr->broadaddr == NULL) { (void)snprintf(errbuf, PCAP_ERRBUF_SIZE, "malloc: %s", pcap_strerror(errno)); free(curaddr); return (-1); } } else curaddr->broadaddr = NULL; if (dstaddr != NULL) { curaddr->dstaddr = dup_sockaddr(dstaddr); if (curaddr->dstaddr == NULL) { (void)snprintf(errbuf, PCAP_ERRBUF_SIZE, "malloc: %s", pcap_strerror(errno)); free(curaddr); return (-1); } } else curaddr->dstaddr = NULL; /* * Find the end of the list of addresses. */ for (prevaddr = curdev->addresses; prevaddr != NULL; prevaddr = nextaddr) { nextaddr = prevaddr->next; if (nextaddr == NULL) { /* * This is the end of the list. */ break; } } if (prevaddr == NULL) { /* * The list was empty; this is the first member. */ curdev->addresses = curaddr; } else { /* * "prevaddr" is the last member of the list; append * this member to it. */ prevaddr->next = curaddr; } return (0); } static int pcap_add_if(pcap_if_t **devlist, char *name, u_int flags, const char *description, char *errbuf) { pcap_if_t *curdev; return (add_or_find_if(&curdev, devlist, name, flags, description, errbuf)); } /* * Get a list of all interfaces that are up and that we can open. * Returns -1 on error, 0 otherwise. * The list, as returned through "alldevsp", may be null if no interfaces * were up and could be opened. */ #ifdef HAVE_IFADDRS_H int pcap_findalldevs(pcap_if_t **alldevsp, char *errbuf) { pcap_if_t *devlist = NULL; struct ifaddrs *ifap, *ifa; struct sockaddr *broadaddr, *dstaddr; int ret = 0; /* * Get the list of interface addresses. * * Note: this won't return information about interfaces * with no addresses; are there any such interfaces * that would be capable of receiving packets? * (Interfaces incapable of receiving packets aren't * very interesting from libpcap's point of view.) * * LAN interfaces will probably have link-layer * addresses; I don't know whether all implementations * of "getifaddrs()" now, or in the future, will return * those. */ if (getifaddrs(&ifap) != 0) { (void)snprintf(errbuf, PCAP_ERRBUF_SIZE, "getifaddrs: %s", pcap_strerror(errno)); return (-1); } for (ifa = ifap; ifa != NULL; ifa = ifa->ifa_next) { /* * Is this interface up? */ if (!(ifa->ifa_flags & IFF_UP)) { /* * No, so don't add it to the list. */ continue; } /* * "ifa_broadaddr" may be non-null even on * non-broadcast interfaces; "ifa_dstaddr" * was, on at least one FreeBSD 4.1 system, * non-null on a non-point-to-point * interface. */ if (ifa->ifa_flags & IFF_BROADCAST) broadaddr = ifa->ifa_broadaddr; else broadaddr = NULL; if (ifa->ifa_flags & IFF_POINTOPOINT) dstaddr = ifa->ifa_dstaddr; else dstaddr = NULL; /* * Add information for this address to the list. */ if (add_addr_to_iflist(&devlist, ifa->ifa_name, ifa->ifa_flags, ifa->ifa_addr, ifa->ifa_netmask, broadaddr, dstaddr, errbuf) < 0) { ret = -1; break; } } freeifaddrs(ifap); if (ret != -1) { /* * We haven't had any errors yet; add the "any" device, * if we can open it. */ if (pcap_add_if(&devlist, "any", 0, any_descr, errbuf) < 0) ret = -1; } if (ret == -1) { /* * We had an error; free the list we've been constructing. */ if (devlist != NULL) { pcap_freealldevs(devlist); devlist = NULL; } } *alldevsp = devlist; return (ret); } #else /* HAVE_IFADDRS_H */ #ifdef HAVE_PROC_NET_DEV /* * Get from "/proc/net/dev" all interfaces listed there; if they're * already in the list of interfaces we have, that won't add another * instance, but if they're not, that'll add them. * * We don't bother getting any addresses for them; it appears you can't * use SIOCGIFADDR on Linux to get IPv6 addresses for interfaces, and, * although some other types of addresses can be fetched with SIOCGIFADDR, * we don't bother with them for now. * * We also don't fail if we couldn't open "/proc/net/dev"; we just leave * the list of interfaces as is. */ static int scan_proc_net_dev(pcap_if_t **devlistp, int fd, char *errbuf) { FILE *proc_net_f; char linebuf[512]; int linenum; unsigned char *p; char name[512]; /* XXX - pick a size */ char *q, *saveq; struct ifreq ifrflags; int ret = 0; proc_net_f = fopen("/proc/net/dev", "r"); if (proc_net_f == NULL) return (0); for (linenum = 1; fgets(linebuf, sizeof linebuf, proc_net_f) != NULL; linenum++) { /* * Skip the first two lines - they're headers. */ if (linenum <= 2) continue; p = &linebuf[0]; /* * Skip leading white space. */ while (*p != '\0' && isspace(*p)) p++; if (*p == '\0' || *p == '\n') continue; /* blank line */ /* * Get the interface name. */ q = &name[0]; while (*p != '\0' && !isspace(*p)) { if (*p == ':') { /* * This could be the separator between a * name and an alias number, or it could be * the separator between a name with no * alias number and the next field. * * If there's a colon after digits, it * separates the name and the alias number, * otherwise it separates the name and the * next field. */ saveq = q; while (isdigit(*p)) *q++ = *p++; if (*p != ':') { /* * That was the next field, * not the alias number. */ q = saveq; } break; } else *q++ = *p++; } *q = '\0'; /* * Get the flags for this interface, and skip it if * it's not up. */ strncpy(ifrflags.ifr_name, name, sizeof(ifrflags.ifr_name)); if (ioctl(fd, SIOCGIFFLAGS, (char *)&ifrflags) < 0) { if (errno == ENXIO) continue; (void)snprintf(errbuf, PCAP_ERRBUF_SIZE, "SIOCGIFFLAGS: %.*s: %s", (int)sizeof(ifrflags.ifr_name), ifrflags.ifr_name, pcap_strerror(errno)); ret = -1; break; } if (!(ifrflags.ifr_flags & IFF_UP)) continue; /* * Add an entry for this interface, with no addresses. */ if (pcap_add_if(devlistp, name, ifrflags.ifr_flags, NULL, errbuf) == -1) { /* * Failure. */ ret = -1; break; } } if (ret != -1) { /* * Well, we didn't fail for any other reason; did we * fail due to an error reading the file? */ if (ferror(proc_net_f)) { (void)snprintf(errbuf, PCAP_ERRBUF_SIZE, "Error reading /proc/net/dev: %s", pcap_strerror(errno)); ret = -1; } } (void)fclose(proc_net_f); return (ret); } #endif /* HAVE_PROC_NET_DEV */ int pcap_findalldevs(pcap_if_t **alldevsp, char *errbuf) { pcap_if_t *devlist = NULL; register int fd; register struct ifreq *ifrp, *ifend, *ifnext; int n; struct ifconf ifc; char *buf = NULL; unsigned buf_size; struct ifreq ifrflags, ifrnetmask, ifrbroadaddr, ifrdstaddr; struct sockaddr *netmask, *broadaddr, *dstaddr; int ret = 0; /* * Create a socket from which to fetch the list of interfaces. */ fd = socket(AF_INET, SOCK_DGRAM, 0); if (fd < 0) { (void)snprintf(errbuf, PCAP_ERRBUF_SIZE, "socket: %s", pcap_strerror(errno)); return (-1); } /* * Start with an 8K buffer, and keep growing the buffer until * we get the entire interface list or fail to get it for some * reason other than EINVAL (which is presumed here to mean * "buffer is too small"). */ buf_size = 8192; for (;;) { buf = malloc(buf_size); if (buf == NULL) { (void)snprintf(errbuf, PCAP_ERRBUF_SIZE, "malloc: %s", pcap_strerror(errno)); (void)close(fd); return (-1); } ifc.ifc_len = buf_size; ifc.ifc_buf = buf; memset(buf, 0, buf_size); if (ioctl(fd, SIOCGIFCONF, (char *)&ifc) < 0 && errno != EINVAL) { (void)snprintf(errbuf, PCAP_ERRBUF_SIZE, "SIOCGIFCONF: %s", pcap_strerror(errno)); (void)close(fd); free(buf); return (-1); } if (ifc.ifc_len < buf_size) break; free(buf); buf_size *= 2; } ifrp = (struct ifreq *)buf; ifend = (struct ifreq *)(buf + ifc.ifc_len); for (; ifrp < ifend; ifrp = ifnext) { n = SA_LEN(&ifrp->ifr_addr) + sizeof(ifrp->ifr_name); if (n < sizeof(*ifrp)) ifnext = ifrp + 1; else ifnext = (struct ifreq *)((char *)ifrp + n); /* * Get the flags for this interface, and skip it if it's * not up. */ strncpy(ifrflags.ifr_name, ifrp->ifr_name, sizeof(ifrflags.ifr_name)); if (ioctl(fd, SIOCGIFFLAGS, (char *)&ifrflags) < 0) { if (errno == ENXIO) continue; (void)snprintf(errbuf, PCAP_ERRBUF_SIZE, "SIOCGIFFLAGS: %.*s: %s", (int)sizeof(ifrflags.ifr_name), ifrflags.ifr_name, pcap_strerror(errno)); ret = -1; break; } if (!(ifrflags.ifr_flags & IFF_UP)) continue; /* * Get the netmask for this address on this interface. */ strncpy(ifrnetmask.ifr_name, ifrp->ifr_name, sizeof(ifrnetmask.ifr_name)); memcpy(&ifrnetmask.ifr_addr, &ifrp->ifr_addr, sizeof(ifrnetmask.ifr_addr)); if (ioctl(fd, SIOCGIFNETMASK, (char *)&ifrnetmask) < 0) { if (errno == EADDRNOTAVAIL) { /* * Not available. */ netmask = NULL; } else { (void)snprintf(errbuf, PCAP_ERRBUF_SIZE, "SIOCGIFNETMASK: %.*s: %s", (int)sizeof(ifrnetmask.ifr_name), ifrnetmask.ifr_name, pcap_strerror(errno)); ret = -1; break; } } else netmask = &ifrnetmask.ifr_addr; /* * Get the broadcast address for this address on this * interface (if any). */ if (ifrflags.ifr_flags & IFF_BROADCAST) { strncpy(ifrbroadaddr.ifr_name, ifrp->ifr_name, sizeof(ifrbroadaddr.ifr_name)); memcpy(&ifrbroadaddr.ifr_addr, &ifrp->ifr_addr, sizeof(ifrbroadaddr.ifr_addr)); if (ioctl(fd, SIOCGIFBRDADDR, (char *)&ifrbroadaddr) < 0) { if (errno == EADDRNOTAVAIL) { /* * Not available. */ broadaddr = NULL; } else { (void)snprintf(errbuf, PCAP_ERRBUF_SIZE, "SIOCGIFBRDADDR: %.*s: %s", (int)sizeof(ifrbroadaddr.ifr_name), ifrbroadaddr.ifr_name, pcap_strerror(errno)); ret = -1; break; } } else broadaddr = &ifrbroadaddr.ifr_broadaddr; } else { /* * Not a broadcast interface, so no broadcast * address. */ broadaddr = NULL; } /* * Get the destination address for this address on this * interface (if any). */ if (ifrflags.ifr_flags & IFF_POINTOPOINT) { strncpy(ifrdstaddr.ifr_name, ifrp->ifr_name, sizeof(ifrdstaddr.ifr_name)); memcpy(&ifrdstaddr.ifr_addr, &ifrp->ifr_addr, sizeof(ifrdstaddr.ifr_addr)); if (ioctl(fd, SIOCGIFDSTADDR, (char *)&ifrdstaddr) < 0) { if (errno == EADDRNOTAVAIL) { /* * Not available. */ dstaddr = NULL; } else { (void)snprintf(errbuf, PCAP_ERRBUF_SIZE, "SIOCGIFDSTADDR: %.*s: %s", (int)sizeof(ifrdstaddr.ifr_name), ifrdstaddr.ifr_name, pcap_strerror(errno)); ret = -1; break; } } else dstaddr = &ifrdstaddr.ifr_dstaddr; } else dstaddr = NULL; /* * Add information for this address to the list. */ if (add_addr_to_iflist(&devlist, ifrp->ifr_name, ifrflags.ifr_flags, &ifrp->ifr_addr, netmask, broadaddr, dstaddr, errbuf) < 0) { ret = -1; break; } } free(buf); #ifdef HAVE_PROC_NET_DEV if (ret != -1) { /* * We haven't had any errors yet; now read "/proc/net/dev", * and add to the list of interfaces all interfaces listed * there that we don't already have, because, on Linux, * SIOCGIFCONF reports only interfaces with IPv4 addresses, * so you need to read "/proc/net/dev" to get the names of * the rest of the interfaces. */ ret = scan_proc_net_dev(&devlist, fd, errbuf); } #endif (void)close(fd); if (ret != -1) { /* * We haven't had any errors yet; add the "any" device, * if we can open it. */ if (pcap_add_if(&devlist, "any", 0, any_descr, errbuf) < 0) { /* * Oops, we had a fatal error. */ ret = -1; } } if (ret == -1) { /* * We had an error; free the list we've been constructing. */ if (devlist != NULL) { pcap_freealldevs(devlist); devlist = NULL; } } *alldevsp = devlist; return (ret); } #endif /* HAVE_IFADDRS_H */ /* * Free a list of interfaces. */ void pcap_freealldevs(pcap_if_t *alldevs) { pcap_if_t *curdev, *nextdev; pcap_addr_t *curaddr, *nextaddr; for (curdev = alldevs; curdev != NULL; curdev = nextdev) { nextdev = curdev->next; /* * Free all addresses. */ for (curaddr = curdev->addresses; curaddr != NULL; curaddr = nextaddr) { nextaddr = curaddr->next; if (curaddr->addr) free(curaddr->addr); if (curaddr->netmask) free(curaddr->netmask); if (curaddr->broadaddr) free(curaddr->broadaddr); if (curaddr->dstaddr) free(curaddr->dstaddr); free(curaddr); } /* * Free the name string. */ free(curdev->name); /* * Free the description string, if any. */ if (curdev->description != NULL) free(curdev->description); /* * Free the interface. */ free(curdev); } } /* * 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; { pcap_if_t *alldevs; /* for old BSD systems, including bsdi3 */ #ifndef IF_NAMESIZE #define IF_NAMESIZE IFNAMSIZ #endif static char device[IF_NAMESIZE + 1]; char *ret; if (pcap_findalldevs(&alldevs, errbuf) == -1) return (NULL); if (alldevs == NULL || (alldevs->flags & PCAP_IF_LOOPBACK)) { /* * There are no devices on the list, or the first device * on the list is a loopback device, which means there * are no non-loopback devices on the list. This means * we can't return any device. * * XXX - why not return a loopback device? If we can't * capture on it, it won't be on the list, and if it's * on the list, there aren't any non-loopback devices, * so why not just supply it as the default device? */ (void)strlcpy(errbuf, "no suitable device found", PCAP_ERRBUF_SIZE); ret = NULL; } else { /* * Return the name of the first device on the list. */ (void)strlcpy(device, alldevs->name, sizeof(device)); ret = device; } pcap_freealldevs(alldevs); return (ret); } 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; /* * The pseudo-device "any" listens on all interfaces and therefore * has the network address and -mask "0.0.0.0" therefore catching * all traffic. Using NULL for the interface is the same as "any". */ if (!device || strcmp(device, "any") == 0) { *netp = *maskp = 0; return 0; } 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) { if (errno == EADDRNOTAVAIL) { (void)snprintf(errbuf, PCAP_ERRBUF_SIZE, "%s: no IPv4 address assigned", device); } else { (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); }