/*      $NetBSD: ifaddrlist.c,v 1.12 2021/10/30 09:26:11 nia Exp $      */

/*
 * Copyright (c) 1997, 1998, 1999, 2000
 *      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>
#ifndef lint
#if 0
static const char rcsid[] =
    "@(#) Header: ifaddrlist.c,v 1.2 97/04/22 13:31:05 leres Exp  (LBL)";
    "@(#) Id: ifaddrlist.c,v 1.9 2000/11/23 20:01:55 leres Exp  (LBL)";
#else
__RCSID("$NetBSD: ifaddrlist.c,v 1.12 2021/10/30 09:26:11 nia Exp $");
#endif
#endif

#include <sys/param.h>
#include <sys/file.h>
#include <sys/ioctl.h>
#include <sys/socket.h>
#ifdef HAVE_SYS_SOCKIO_H
#include <sys/sockio.h>
#endif
#include <sys/time.h>                           /* concession to AIX */

struct mbuf;
struct rtentry;

#include <net/if.h>
#include <netinet/in.h>
#include <arpa/inet.h>

#include <ctype.h>
#include <errno.h>
#include <memory.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <ifaddrs.h>

#include "gnuc.h"
#ifdef HAVE_OS_PROTO_H
#include "os-proto.h"
#endif

#include "ifaddrlist.h"
#include "prog_ops.h"

/* Not all systems have IFF_LOOPBACK */
#ifdef IFF_LOOPBACK
#define ISLOOPBACK(p) ((p)->ifa_flags & IFF_LOOPBACK)
#else
#define ISLOOPBACK(p) (strcmp((p)->ifa_name, "lo0") == 0)
#endif

/*
 * Return the interface list
 */
ssize_t
ifaddrlist(struct ifaddrlist **ipaddrp, char *errbuf, size_t buflen)
{
        struct sockaddr_in *sin;
        struct ifaddrs *ifap = NULL, *ifa;
        struct ifaddrlist *al = NULL;
        size_t i = 0, maxal = 10;

        if (prog_getifaddrs(&ifap) != 0)
                goto out;

        if (reallocarr(&al, maxal, sizeof(*al)) != 0)
                goto out;
                
        for (ifa = ifap; ifa; ifa = ifa->ifa_next) {
                if (ifa->ifa_addr->sa_family != AF_INET)
                        continue;

                /* Must be up */
                if ((ifa->ifa_flags & IFF_UP) == 0)
                        continue;

                /*
                 * Must not be a loopback address (127/8)
                 */
                sin = (struct sockaddr_in *)ifa->ifa_addr;
                if (ISLOOPBACK(ifa))
                        if (ntohl(sin->sin_addr.s_addr) == INADDR_LOOPBACK)
                                continue;

                if (i == maxal) {
                        maxal <<= 1;
                        if (reallocarr(&al, maxal, sizeof(*al)) != 0)
                                goto out;
                }

                al[i].addr = sin->sin_addr.s_addr;
                if ((al[i].device = strdup(ifa->ifa_name)) == NULL)
                        goto out;
                i++;
        }
        if (reallocarr(&al, i, sizeof(*al)) != 0)
                goto out;
        freeifaddrs(ifap);
        *ipaddrp = al;
        return (ssize_t)i;
out:
        if (ifap)
                freeifaddrs(ifap);
        if (al) {
                while (i > 0)
                        free(al[--i].device);
                free(al);
        }
        (void)snprintf(errbuf, buflen, "%s: %s", __func__, strerror(errno));
        return -1;
}