/* -*- 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. */ #include <sys/types.h> #include <sys/socket.h> #include <netinet/in.h> #include <net/if.h> #include <ctype.h> #include <errno.h> #include <stdio.h> #include <stdlib.h> #include <string.h> #include <ifaddrs.h> #include <limits.h> #include "pcap-int.h" static struct sockaddr * dup_sockaddr(struct sockaddr *sa, size_t sa_length) { struct sockaddr *newsa; if ((newsa = malloc(sa_length)) == NULL) return (NULL); return (memcpy(newsa, sa, sa_length)); } static int get_instance(const char *name) { const char *cp, *endcp, *errstr; 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; n = strtonum(cp, 0, INT_MAX, &errstr); if (errstr != NULL) return -1; return n; } static int add_or_find_if(pcap_if_t **curdev_ret, pcap_if_t **alldevs, const char *name, u_int flags, const char *description, char *errbuf) { pcap_t *p; pcap_if_t *curdev, *prevdev, *nextdev; int this_instance; size_t len; /* * Can we open this interface for live capture? * * We do this check so that interfaces that are supplied * by the interface enumeration mechanism we're using * but that don't support packet capture aren't included * in the list. An example of this is loopback interfaces * on Solaris; we don't just omit loopback interfaces * because you *can* capture on loopback interfaces on some * OSes. */ 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 = calloc(1, sizeof(pcap_if_t)); if (curdev == NULL) { (void)snprintf(errbuf, PCAP_ERRBUF_SIZE, "calloc: %s", pcap_strerror(errno)); goto fail; } /* * Fill in the entry. */ curdev->next = NULL; len = strlen(name) + 1; curdev->name = malloc(len); if (curdev->name == NULL) { (void)snprintf(errbuf, PCAP_ERRBUF_SIZE, "malloc: %s", pcap_strerror(errno)); goto fail; } strlcpy(curdev->name, name, len); if (description != NULL) { /* * We have a description for this interface. */ len = strlen(description) + 1; curdev->description = malloc(len); if (curdev->description == NULL) { (void)snprintf(errbuf, PCAP_ERRBUF_SIZE, "malloc: %s", pcap_strerror(errno)); goto fail; } strlcpy(curdev->description, description, len); } 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. */ if ((this_instance = get_instance(name)) == -1) { (void)snprintf(errbuf, PCAP_ERRBUF_SIZE, "malformed device name: %s", name); goto fail; } /* * 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); fail: if (curdev != NULL) { free(curdev->name); free(curdev->description); free(curdev); } return (-1); } static int add_addr_to_iflist(pcap_if_t **alldevs, const char *name, u_int flags, struct sockaddr *addr, size_t addr_size, struct sockaddr *netmask, size_t netmask_size, struct sockaddr *broadaddr, size_t broadaddr_size, struct sockaddr *dstaddr, size_t dstaddr_size, 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 = calloc(1, sizeof(pcap_addr_t)); if (curaddr == NULL) { (void)snprintf(errbuf, PCAP_ERRBUF_SIZE, "calloc: %s", pcap_strerror(errno)); goto fail; } curaddr->next = NULL; if (addr != NULL) { curaddr->addr = dup_sockaddr(addr, addr_size); if (curaddr->addr == NULL) { (void)snprintf(errbuf, PCAP_ERRBUF_SIZE, "malloc: %s", pcap_strerror(errno)); goto fail; } } if (netmask != NULL) { curaddr->netmask = dup_sockaddr(netmask, netmask_size); if (curaddr->netmask == NULL) { (void)snprintf(errbuf, PCAP_ERRBUF_SIZE, "malloc: %s", pcap_strerror(errno)); goto fail; } } if (broadaddr != NULL) { curaddr->broadaddr = dup_sockaddr(broadaddr, broadaddr_size); if (curaddr->broadaddr == NULL) { (void)snprintf(errbuf, PCAP_ERRBUF_SIZE, "malloc: %s", pcap_strerror(errno)); goto fail; } } if (dstaddr != NULL) { curaddr->dstaddr = dup_sockaddr(dstaddr, dstaddr_size); if (curaddr->dstaddr == NULL) { (void)snprintf(errbuf, PCAP_ERRBUF_SIZE, "malloc: %s", pcap_strerror(errno)); goto fail; } } /* * 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); fail: if (curaddr != NULL) { free(curaddr->addr); free(curaddr->netmask); free(curaddr->broadaddr); free(curaddr->dstaddr); free(curaddr); } return (-1); } /* * 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. * * This is the implementation used on platforms that have "getifaddrs()". */ int pcap_findalldevs(pcap_if_t **alldevsp, char *errbuf) { pcap_if_t *devlist = NULL; struct ifaddrs *ifap, *ifa; struct sockaddr *addr, *netmask, *broadaddr, *dstaddr; size_t addr_size, broadaddr_size, dstaddr_size; 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_addr" was apparently null on at least one * interface on some system. * * "ifa_broadaddr" may be non-null even on * non-broadcast interfaces, and was null on * at least one OpenBSD 3.4 system on at least * one interface with IFF_BROADCAST set. * * "ifa_dstaddr" was, on at least one FreeBSD 4.1 * system, non-null on a non-point-to-point * interface. * * Therefore, we supply the address and netmask only * if "ifa_addr" is non-null (if there's no address, * there's obviously no netmask), and supply the * broadcast and destination addresses if the appropriate * flag is set *and* the appropriate "ifa_" entry doesn't * evaluate to a null pointer. */ if (ifa->ifa_addr != NULL) { addr = ifa->ifa_addr; addr_size = SA_LEN(addr); netmask = ifa->ifa_netmask; } else { addr = NULL; addr_size = 0; netmask = NULL; } if (ifa->ifa_flags & IFF_BROADCAST && ifa->ifa_broadaddr != NULL) { broadaddr = ifa->ifa_broadaddr; broadaddr_size = SA_LEN(broadaddr); } else { broadaddr = NULL; broadaddr_size = 0; } if (ifa->ifa_flags & IFF_POINTOPOINT && ifa->ifa_dstaddr != NULL) { dstaddr = ifa->ifa_dstaddr; dstaddr_size = SA_LEN(ifa->ifa_dstaddr); } else { dstaddr = NULL; dstaddr_size = 0; } /* * Add information for this address to the list. */ if (add_addr_to_iflist(&devlist, ifa->ifa_name, ifa->ifa_flags, addr, addr_size, netmask, addr_size, broadaddr, broadaddr_size, dstaddr, dstaddr_size, errbuf) < 0) { ret = -1; break; } } freeifaddrs(ifap); 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); }
