/*-
 * SPDX-License-Identifier: BSD-2-Clause
 *
 * Copyright (c) 2003 Bruce M. Simpson.
 * 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.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 AUTHOR 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 "namespace.h"
#include <sys/param.h>
#include <sys/sysctl.h>
#include <sys/ioctl.h>
#include <sys/socket.h>
#include <net/if.h>
#include <net/if_dl.h>
#include <net/route.h>

#include <errno.h>
#include <ifaddrs.h>
#include <stdlib.h>
#include <string.h>
#include "un-namespace.h"

#define SALIGN  (sizeof(long) - 1)
#define SA_RLEN(sa)     ((sa)->sa_len ? (((sa)->sa_len + SALIGN) & ~SALIGN) : \
                            (SALIGN + 1))
#define MAX_SYSCTL_TRY  5
#define RTA_MASKS       (RTA_GATEWAY | RTA_IFP | RTA_IFA)

int
getifmaddrs(struct ifmaddrs **pif)
{
        int icnt = 1;
        int dcnt = 0;
        int ntry = 0;
        size_t len;
        size_t needed;
        int mib[6];
        int i;
        char *buf;
        char *data;
        char *next;
        char *p;
        struct ifma_msghdr *ifmam;
        struct ifmaddrs *ifa, *ift;
        struct rt_msghdr *rtm;
        struct sockaddr *sa;

        mib[0] = CTL_NET;
        mib[1] = PF_ROUTE;
        mib[2] = 0;             /* protocol */
        mib[3] = 0;             /* wildcard address family */
        mib[4] = NET_RT_IFMALIST;
        mib[5] = 0;             /* no flags */
        do {
                if (sysctl(mib, 6, NULL, &needed, NULL, 0) < 0)
                        return (-1);
                if ((buf = malloc(needed)) == NULL)
                        return (-1);
                if (sysctl(mib, 6, buf, &needed, NULL, 0) < 0) {
                        if (errno != ENOMEM || ++ntry >= MAX_SYSCTL_TRY) {
                                free(buf);
                                return (-1);
                        }
                        free(buf);
                        buf = NULL;
                } 
        } while (buf == NULL);

        for (next = buf; next < buf + needed; next += rtm->rtm_msglen) {
                rtm = (struct rt_msghdr *)(void *)next;
                if (rtm->rtm_version != RTM_VERSION)
                        continue;
                switch (rtm->rtm_type) {
                case RTM_NEWMADDR:
                        ifmam = (struct ifma_msghdr *)(void *)rtm;
                        if ((ifmam->ifmam_addrs & RTA_IFA) == 0)
                                break;
                        icnt++;
                        p = (char *)(ifmam + 1);
                        for (i = 0; i < RTAX_MAX; i++) {
                                if ((RTA_MASKS & ifmam->ifmam_addrs &
                                    (1 << i)) == 0)
                                        continue;
                                sa = (struct sockaddr *)(void *)p;
                                len = SA_RLEN(sa);
                                dcnt += len;
                                p += len;
                        }
                        break;
                }
        }

        data = malloc(sizeof(struct ifmaddrs) * icnt + dcnt);
        if (data == NULL) {
                free(buf);
                return (-1);
        }

        ifa = (struct ifmaddrs *)(void *)data;
        data += sizeof(struct ifmaddrs) * icnt;

        memset(ifa, 0, sizeof(struct ifmaddrs) * icnt);
        ift = ifa;

        for (next = buf; next < buf + needed; next += rtm->rtm_msglen) {
                rtm = (struct rt_msghdr *)(void *)next;
                if (rtm->rtm_version != RTM_VERSION)
                        continue;

                switch (rtm->rtm_type) {
                case RTM_NEWMADDR:
                        ifmam = (struct ifma_msghdr *)(void *)rtm;
                        if ((ifmam->ifmam_addrs & RTA_IFA) == 0)
                                break;

                        p = (char *)(ifmam + 1);
                        for (i = 0; i < RTAX_MAX; i++) {
                                if ((RTA_MASKS & ifmam->ifmam_addrs &
                                    (1 << i)) == 0)
                                        continue;
                                sa = (struct sockaddr *)(void *)p;
                                len = SA_RLEN(sa);
                                switch (i) {
                                case RTAX_GATEWAY:
                                        ift->ifma_lladdr =
                                            (struct sockaddr *)(void *)data;
                                        memcpy(data, p, len);
                                        data += len;
                                        break;

                                case RTAX_IFP:
                                        ift->ifma_name =
                                            (struct sockaddr *)(void *)data;
                                        memcpy(data, p, len);
                                        data += len;
                                        break;

                                case RTAX_IFA:
                                        ift->ifma_addr =
                                            (struct sockaddr *)(void *)data;
                                        memcpy(data, p, len);
                                        data += len;
                                        break;

                                default:
                                        data += len;
                                        break;
                                }
                                p += len;
                        }
                        ift->ifma_next = ift + 1;
                        ift = ift->ifma_next;
                        break;
                }
        }

        free(buf);

        if (ift > ifa) {
                ift--;
                ift->ifma_next = NULL;
                *pif = ifa;
        } else {
                *pif = NULL;
                free(ifa);
        }
        return (0);
}

void
freeifmaddrs(struct ifmaddrs *ifmp)
{

        free(ifmp);
}