/*      $OpenBSD: getifaddrs.c,v 1.15 2025/11/13 10:34:32 deraadt Exp $ */

/*
 * Copyright (c) 1995, 1999
 *      Berkeley Software Design, Inc.  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.
 *
 * THIS SOFTWARE IS PROVIDED BY Berkeley Software Design, Inc. ``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 Berkeley Software Design, Inc. 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.
 *
 *      BSDI getifaddrs.c,v 2.12 2000/02/23 14:51:59 dab Exp
 */

#include <sys/types.h>
#include <sys/ioctl.h>
#include <sys/socket.h>
#include <sys/syslog.h>
#include <net/if.h>
#include <net/route.h>
#include <sys/sysctl.h>
#include <net/if_dl.h>

#include <errno.h>
#include <ifaddrs.h>
#include <stddef.h>
#include <stdlib.h>
#include <stdint.h>
#include <string.h>
#include <unistd.h>
#include <stdio.h>

#define roundup(x, y)   ((((uintptr_t)(x)+((y)-1))/(y))*(y))
#define proundup(x, y)  (void *)roundup(x,y)

#define SA_RLEN(sa)     ((sa)->sa_len ? \
                            roundup((sa)->sa_len, sizeof(long)) : \
                            roundup(1, sizeof(long)))

int
getifaddrs(struct ifaddrs **pif)
{
        int icnt = 1, dcnt = 0, ncnt = 0, mib[6], i;
        size_t needed;
        char *buf = NULL, *bufp, *data, *names, *next, *p, *p0;
        struct ifaddrs *cif = 0, *ifa, *ift;
        struct rt_msghdr *rtm;
        struct if_msghdr *ifm;
        struct ifa_msghdr *ifam;
        struct sockaddr_dl *dl;
        struct sockaddr *sa;
        u_short index = 0;
        size_t len, alen, dlen, dsize;

        mib[0] = CTL_NET;
        mib[1] = PF_ROUTE;
        mib[2] = 0;             /* protocol */
        mib[3] = 0;             /* wildcard address family */
        mib[4] = NET_RT_IFLIST;
        mib[5] = 0;             /* no flags */
        while (1) {
                if (sysctl(mib, 6, NULL, &needed, NULL, 0) == -1) {
                        free(buf);
                        return (-1);
                }
                if (needed == 0)
                        break;
                if ((bufp = realloc(buf, needed)) == NULL) {
                        free(buf);
                        return (-1);
                }
                buf = bufp;
                if (sysctl(mib, 6, buf, &needed, NULL, 0) == -1) {
                        if (errno == ENOMEM)
                                continue;
                        free(buf);
                        return (-1);
                }
                break;
        }

        /* Calculate data buffer size */
        for (next = buf; next < buf + needed; next += rtm->rtm_msglen) {
                rtm = (struct rt_msghdr *)next;
                if (rtm->rtm_version != RTM_VERSION)
                        continue;
                switch (rtm->rtm_type) {
                case RTM_IFINFO:
                        ifm = (struct if_msghdr *)rtm;
                        if (ifm->ifm_addrs & RTA_IFP) {
                                index = ifm->ifm_index;
                                ++icnt;
                                dl = (struct sockaddr_dl *)(next +
                                    rtm->rtm_hdrlen);
                                ncnt += dl->sdl_nlen + 1;

                                /* sockaddr's need long alignment */
                                dcnt = roundup(dcnt, sizeof(long));
                                dcnt += SA_RLEN((struct sockaddr *)dl);

                                /* ifm_data[] needs long long alignment */
                                dcnt = roundup(dcnt, sizeof(long long));
                                dcnt += sizeof(ifm->ifm_data);
                        } else
                                index = 0;
                        break;

                case RTM_NEWADDR:
                        ifam = (struct ifa_msghdr *)rtm;
                        if (index && ifam->ifam_index != index)
                                abort();        /* XXX abort illegal in library */

#define RTA_MASKS       (RTA_NETMASK | RTA_IFA | RTA_BRD)
                        if (index == 0 || (ifam->ifam_addrs & RTA_MASKS) == 0)
                                break;
                        p = next + rtm->rtm_hdrlen;
                        ++icnt;
                        /* Scan to look for length of address */
                        alen = 0;
                        for (p0 = p, i = 0; i < RTAX_MAX; i++) {
                                if ((RTA_MASKS & ifam->ifam_addrs & (1 << i))
                                    == 0)
                                        continue;
                                sa = (struct sockaddr *)p;
                                len = SA_RLEN(sa);
                                if (i == RTAX_IFA) {
                                        alen = len;
                                        break;
                                }
                                p += len;
                        }
                        for (p = p0, i = 0; i < RTAX_MAX; i++) {
                                if ((RTA_MASKS & ifam->ifam_addrs & (1 << i))
                                    == 0)
                                        continue;
                                sa = (struct sockaddr *)p;
                                len = SA_RLEN(sa);
                                /* sockaddr's need long alignment */
                                dcnt = roundup(dcnt, sizeof(long));
                                if (i == RTAX_NETMASK && sa->sa_len == 0)
                                        dcnt += alen;
                                else
                                        dcnt += len;
                                p += len;
                        }
                        break;
                }
        }

        if (icnt + ncnt + dcnt == 1) {
                *pif = NULL;
                free(buf);
                return (0);
        }

        dsize = sizeof(struct ifaddrs) * icnt;
        dsize += ncnt;
        dsize = roundup(dsize, sizeof(long long));
        dsize += dcnt;

        data = calloc(dsize, 1);
        if (data == NULL) {
                free(buf);
                return(-1);
        }

        /* ifaddrs[], names, then if_data[] */
        ift = ifa = (struct ifaddrs *)data;
        data += sizeof(struct ifaddrs) * icnt;
        names = data;
        data += ncnt;
        data = proundup(data, sizeof(long long));

        index = 0;
        for (next = buf; next < buf + needed; next += rtm->rtm_msglen) {
                rtm = (struct rt_msghdr *)next;
                if (rtm->rtm_version != RTM_VERSION)
                        continue;
                switch (rtm->rtm_type) {
                case RTM_IFINFO:
                        ifm = (struct if_msghdr *)rtm;
                        if (ifm->ifm_addrs & RTA_IFP) {
                                index = ifm->ifm_index;
                                dl = (struct sockaddr_dl *)(next +
                                    rtm->rtm_hdrlen);

                                cif = ift;
                                ift->ifa_name = names;
                                ift->ifa_flags = (int)ifm->ifm_flags;
                                memcpy(names, dl->sdl_data, dl->sdl_nlen);
                                names[dl->sdl_nlen] = 0;
                                names += dl->sdl_nlen + 1;

                                data = proundup(data, sizeof(long));
                                ift->ifa_addr = (struct sockaddr *)data;
                                memcpy(data, dl,
                                    ((struct sockaddr *)dl)->sa_len);
                                data += SA_RLEN((struct sockaddr *)dl);

                                /* if_data needs long long alignment */
                                data = proundup(data, sizeof(long long));
                                ift->ifa_data = data;
                                dlen = rtm->rtm_hdrlen -
                                    offsetof(struct if_msghdr, ifm_data);
                                if (dlen > sizeof(ifm->ifm_data))
                                        dlen = sizeof(ifm->ifm_data);
                                memcpy(data, &ifm->ifm_data, dlen);
                                data += dlen;

                                ift = (ift->ifa_next = ift + 1);
                        } else
                                index = 0;
                        break;

                case RTM_NEWADDR:
                        ifam = (struct ifa_msghdr *)rtm;
                        if (index && ifam->ifam_index != index)
                                abort();        /* XXX abort illegal in library */

                        if (index == 0 || (ifam->ifam_addrs & RTA_MASKS) == 0)
                                break;
                        ift->ifa_name = cif->ifa_name;
                        ift->ifa_flags = cif->ifa_flags;
                        ift->ifa_data = NULL;
                        p = next + rtm->rtm_hdrlen;
                        /* Scan to look for length of address */
                        alen = 0;
                        for (p0 = p, i = 0; i < RTAX_MAX; i++) {
                                if ((RTA_MASKS & ifam->ifam_addrs & (1 << i))
                                    == 0)
                                        continue;
                                sa = (struct sockaddr *)p;
                                len = SA_RLEN(sa);
                                if (i == RTAX_IFA) {
                                        alen = len;
                                        break;
                                }
                                p += len;
                        }
                        for (p = p0, i = 0; i < RTAX_MAX; i++) {
                                if ((RTA_MASKS & ifam->ifam_addrs & (1 << i))
                                    == 0)
                                        continue;
                                sa = (struct sockaddr *)p;
                                len = SA_RLEN(sa);
                                switch (i) {
                                case RTAX_IFA:
                                        data = proundup(data, sizeof(long));
                                        ift->ifa_addr = (struct sockaddr *)data;
                                        memcpy(data, p, len);
                                        data += len;
                                        break;

                                case RTAX_NETMASK:
                                        data = proundup(data, sizeof(long));
                                        ift->ifa_netmask =
                                            (struct sockaddr *)data;
                                        if (sa->sa_len == 0) {
                                                memset(data, 0, alen);
                                                data += alen;
                                                break;
                                        }
                                        memcpy(data, p, len);
                                        data += len;
                                        break;

                                case RTAX_BRD:
                                        data = proundup(data, sizeof(long));
                                        ift->ifa_broadaddr =
                                            (struct sockaddr *)data;
                                        memcpy(data, p, len);
                                        data += len;
                                        break;
                                }
                                p += len;
                        }


                        ift = (ift->ifa_next = ift + 1);
                        break;
                }
        }

        /* XXX temporary paranoia until we are sure it is bug free */
        if (dsize != (char *)data - (char *)ifa) {
                char buf[1024];

                /* <10> is LOG_CRIT */
                snprintf(buf, sizeof buf,
                    "<10>%s: getifaddrs: allocated %lu used %lu\n",
                    __progname, dsize, (char *)data - (char *)ifa);
                sendsyslog(buf, strlen(buf), LOG_CONS);
        }

        free(buf);
        if (--ift >= ifa) {
                ift->ifa_next = NULL;
                *pif = ifa;
        } else {
                *pif = NULL;
                free(ifa);
        }
        return (0);
}
DEF_WEAK(getifaddrs);

void
freeifaddrs(struct ifaddrs *ifp)
{
        free(ifp);
}
DEF_WEAK(freeifaddrs);