/* $NetBSD: fad-getad.c,v 1.6 2024/09/02 15:33:36 christos Exp $ */
/* -*- 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/cdefs.h>
__RCSID("$NetBSD: fad-getad.c,v 1.6 2024/09/02 15:33:36 christos Exp $");
#include <config.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <net/if.h>
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <ifaddrs.h>
#include "pcap-int.h"
#ifdef HAVE_OS_PROTO_H
#include "os-proto.h"
#endif
/*
* We don't do this on Solaris 11 and later, as it appears there aren't
* any AF_PACKET addresses on interfaces, so we don't need this, and
* we end up including both the OS's <net/bpf.h> and our <pcap/bpf.h>,
* and their definitions of some data structures collide.
*/
#if (defined(__linux__) || defined(__Lynx__)) && defined(AF_PACKET)
# ifdef HAVE_NETPACKET_PACKET_H
/* Linux distributions with newer glibc */
# include <netpacket/packet.h>
# else /* HAVE_NETPACKET_PACKET_H */
/* LynxOS, Linux distributions with older glibc */
# ifdef __Lynx__
/* LynxOS */
# include <netpacket/if_packet.h>
# else /* __Lynx__ */
/* Linux */
# include <linux/types.h>
# include <linux/if_packet.h>
# endif /* __Lynx__ */
# endif /* HAVE_NETPACKET_PACKET_H */
#endif /* (defined(__linux__) || defined(__Lynx__)) && defined(AF_PACKET) */
/*
* 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, some use the RFC 2553
* variant of the old BSD scheme (with "struct sockaddr_storage" rather
* than "struct sockaddr"), and some use the new BSD scheme.
*
* Some versions of GNU libc use neither scheme, but has an "SA_LEN()"
* macro that determines the size based on the address family. Other
* versions don't have "SA_LEN()" (as it was in drafts of RFC 2553
* but not in the final version). On the latter systems, we explicitly
* check the AF_ type to determine the length; we assume that on
* all those systems we have "struct sockaddr_storage".
*
* OSes that use this file are:
* - FreeBSD (HAVE_STRUCT_SOCKADDR_SA_LEN is defined)
* - Haiku (HAVE_STRUCT_SOCKADDR_SA_LEN is defined)
* - Hurd (HAVE_STRUCT_SOCKADDR_SA_LEN is defined)
* - illumos (HAVE_STRUCT_SOCKADDR_SA_LEN is not defined)
* - Linux (HAVE_STRUCT_SOCKADDR_SA_LEN is not defined)
* - macOS (HAVE_STRUCT_SOCKADDR_SA_LEN is defined)
* - NetBSD (HAVE_STRUCT_SOCKADDR_SA_LEN is defined)
* - OpenBSD (SA_LEN() is defined)
* - Solaris 11 (HAVE_STRUCT_SOCKADDR_SA_LEN is not defined)
*/
#ifndef SA_LEN
#ifdef HAVE_STRUCT_SOCKADDR_SA_LEN
#define SA_LEN(addr) ((addr)->sa_len)
#else /* HAVE_STRUCT_SOCKADDR_SA_LEN */
#ifdef HAVE_STRUCT_SOCKADDR_STORAGE
static size_t
get_sa_len(struct sockaddr *addr)
{
switch (addr->sa_family) {
#ifdef AF_INET
case AF_INET:
return (sizeof (struct sockaddr_in));
#endif
#ifdef AF_INET6
case AF_INET6:
return (sizeof (struct sockaddr_in6));
#endif
#if (defined(__linux__) || defined(__Lynx__)) && defined(AF_PACKET)
case AF_PACKET:
return (sizeof (struct sockaddr_ll));
#endif
#ifdef AF_LINK
case AF_LINK:
return (sizeof (struct sockaddr_dl));
#endif
default:
return (sizeof (struct sockaddr));
}
}
#define SA_LEN(addr) (get_sa_len(addr))
#else /* HAVE_STRUCT_SOCKADDR_STORAGE */
#define SA_LEN(addr) (sizeof (struct sockaddr))
#endif /* HAVE_STRUCT_SOCKADDR_STORAGE */
#endif /* HAVE_STRUCT_SOCKADDR_SA_LEN */
#endif /* SA_LEN */
/*
* 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
* could be opened.
*/
int
pcapint_findalldevs_interfaces(pcap_if_list_t *devlistp, char *errbuf,
int (*check_usable)(const char *), get_if_flags_func get_flags_func)
{
struct ifaddrs *ifap, *ifa;
struct sockaddr *addr, *netmask, *broadaddr, *dstaddr;
size_t addr_size, broadaddr_size, dstaddr_size;
int ret = 0;
char *p, *q;
/*
* Get the list of interface addresses.
*
* Note: this won't return information about interfaces
* with no addresses, so, if a platform has interfaces
* with no interfaces on which traffic can be captured,
* we must check for those interfaces as well (see, for
* example, what's done on Linux).
*
* 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) {
pcapint_fmt_errmsg_for_errno(errbuf, PCAP_ERRBUF_SIZE,
errno, "getifaddrs");
return (-1);
}
for (ifa = ifap; ifa != NULL; ifa = ifa->ifa_next) {
/*
* If this entry has a colon followed by a number at
* the end, we assume it's a logical interface. Those
* are just the way you assign multiple IP addresses to
* a real interface on Linux, so an entry for a logical
* interface should be treated like the entry for the
* real interface; we do that by stripping off the ":"
* and the number.
*
* XXX - should we do this only on Linux?
*/
p = strchr(ifa->ifa_name, ':');
if (p != NULL) {
/*
* We have a ":"; is it followed by a number?
*/
q = p + 1;
while (PCAP_ISDIGIT(*q))
q++;
if (*q == '\0') {
/*
* All digits after the ":" until the end.
* Strip off the ":" and everything after
* it.
*/
*p = '\0';
}
}
/*
* Can we capture on this device?
*/
if (!(*check_usable)(ifa->ifa_name)) {
/*
* No.
*/
continue;
}
/*
* "ifa_addr" was apparently null on at least one
* interface on some system. Therefore, we supply
* the address and netmask only if "ifa_addr" is
* non-null (if there's no address, there's obviously
* no netmask).
*/
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;
}
/*
* Note that, on some platforms, ifa_broadaddr and
* ifa_dstaddr could be the same field (true on at
* least some versions of *BSD and macOS), so we
* can't just check whether the broadcast address
* is null and add it if so and check whether the
* destination address is null and add it if so.
*
* Therefore, we must also check the IFF_BROADCAST
* flag, and only add a broadcast address if it's
* set, and check the IFF_POINTTOPOINT flag, and
* only add a destination address if it's set (as
* per man page recommendations on some of those
* platforms).
*/
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 (pcapint_add_addr_to_if(devlistp, ifa->ifa_name, ifa->ifa_flags,
get_flags_func,
addr, addr_size, netmask, addr_size,
broadaddr, broadaddr_size, dstaddr, dstaddr_size,
errbuf) < 0) {
ret = -1;
break;
}
}
freeifaddrs(ifap);
return (ret);
}
