/*-
 * SPDX-License-Identifier: BSD-3-Clause
 *
 * Copyright (c) 1984, 1993
 *      The Regents of the University of California.  All rights reserved.
 * Copyright (c) 1994
 *      Geoffrey M. Rehmet, All rights reserved.
 *
 * This code is derived from software which forms part of the 4.4-Lite
 * Berkeley software distribution, which was in derived from software
 * contributed to Berkeley by Sun Microsystems, Inc.
 *
 * 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. Neither the name of the University nor the names of its contributors
 *    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.
 */

/*
 * from arp.c   8.2 (Berkeley) 1/2/94
 */

#include <sys/param.h>
/*
 * Verify that we are at least 4.4 BSD
 */
#if defined(BSD)
#if BSD >= 199306

#include <sys/socket.h>
#include <sys/filio.h>
#include <sys/time.h>

#include <net/if.h>
#include <net/if_dl.h>
#include <net/if_types.h>
#include <net/route.h>

#include <netinet/in.h>
#include <netinet/if_ether.h>

#include <arpa/inet.h>

#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <syslog.h>
#include <unistd.h>

#include "report.h"


static int rtmsg(int);

static int s = -1;      /* routing socket */


/*
 * Open the routing socket
 */
static void getsocket () {
        if (s < 0) {
                s = socket(PF_ROUTE, SOCK_RAW, 0);
                if (s < 0) {
                        report(LOG_ERR, "socket %s", strerror(errno));
                        exit(1);
                }
        } else {
                /*
                 * Drain the socket of any unwanted routing messages.
                 */
                int n;
                char buf[512];

                ioctl(s, FIONREAD, &n);
                while (n > 0) {
                        read(s, buf, sizeof buf);
                        ioctl(s, FIONREAD, &n);
                }
        }
}

static struct   sockaddr_in so_mask = {8, 0, 0, { 0xffffffff}};
static struct   sockaddr_in blank_sin = {sizeof(blank_sin), AF_INET }, sin_m;
static struct   sockaddr_dl blank_sdl = {sizeof(blank_sdl), AF_LINK }, sdl_m;
static int      expire_time, flags, doing_proxy;
static struct   {
        struct  rt_msghdr m_rtm;
        char    m_space[512];
}       m_rtmsg;

/*
 * Set an individual arp entry
 */
int
bsd_arp_set(struct in_addr *ia, char *eaddr, int len)
{
        struct sockaddr_in *sin = &sin_m;
        struct sockaddr_dl *sdl;
        struct rt_msghdr *rtm = &(m_rtmsg.m_rtm);
        u_char *ea;
        struct timespec tp;
        int op = RTM_ADD;

        getsocket();
        sdl_m = blank_sdl;
        sin_m = blank_sin;
        sin->sin_addr = *ia;

        ea = (u_char *)LLADDR(&sdl_m);
        bcopy(eaddr, ea, len);
        sdl_m.sdl_alen = len;
        doing_proxy = flags = expire_time = 0;

        /* make arp entry temporary */
        clock_gettime(CLOCK_MONOTONIC, &tp);
        expire_time = tp.tv_sec + 20 * 60;

tryagain:
        if (rtmsg(RTM_GET) < 0) {
                report(LOG_WARNING, "rtmget: %s", strerror(errno));
                return (1);
        }
        sin = (struct sockaddr_in *)(rtm + 1);
        sdl = (struct sockaddr_dl *)(sin->sin_len + (char *)sin);
        if (sin->sin_addr.s_addr == sin_m.sin_addr.s_addr) {
                if (sdl->sdl_family == AF_LINK &&
                    !(rtm->rtm_flags & RTF_GATEWAY)) switch (sdl->sdl_type) {
                case IFT_ETHER: case IFT_FDDI: case IFT_ISO88023:
                case IFT_ISO88024: case IFT_ISO88025:
                        op = RTM_CHANGE;
                        goto overwrite;
                }
                if (doing_proxy == 0) {
                        report(LOG_WARNING, "set: can only proxy for %s\n",
                                inet_ntoa(sin->sin_addr));
                        return (1);
                }
                goto tryagain;
        }
overwrite:
        if (sdl->sdl_family != AF_LINK) {
                report(LOG_WARNING,
                        "cannot intuit interface index and type for %s\n",
                        inet_ntoa(sin->sin_addr));
                return (1);
        }
        sdl_m.sdl_type = sdl->sdl_type;
        sdl_m.sdl_index = sdl->sdl_index;
        return (rtmsg(op));
}


static int
rtmsg(int cmd)
{
        static int seq;
        int rlen;
        struct rt_msghdr *rtm = &m_rtmsg.m_rtm;
        char *cp = m_rtmsg.m_space;
        int l;

        errno = 0;
        bzero((char *)&m_rtmsg, sizeof(m_rtmsg));
        rtm->rtm_flags = flags;
        rtm->rtm_version = RTM_VERSION;

        switch (cmd) {
        default:
                report(LOG_ERR, "set_arp: internal wrong cmd - exiting");
                exit(1);
        case RTM_ADD:
        case RTM_CHANGE:
                rtm->rtm_addrs |= RTA_GATEWAY;
                rtm->rtm_rmx.rmx_expire = expire_time;
                rtm->rtm_inits = RTV_EXPIRE;
                rtm->rtm_flags |= (RTF_HOST | RTF_STATIC | RTF_LLDATA);
                if (doing_proxy) {
                        rtm->rtm_addrs |= RTA_NETMASK;
                        rtm->rtm_flags &= ~RTF_HOST;
                }
                /* FALLTHROUGH */
        case RTM_GET:
                rtm->rtm_addrs |= RTA_DST;
        }
#define NEXTADDR(w, s) \
        if (rtm->rtm_addrs & (w)) { \
                bcopy((char *)&s, cp, sizeof(s)); cp += sizeof(s);}

        NEXTADDR(RTA_DST, sin_m);
        NEXTADDR(RTA_GATEWAY, sdl_m);
        NEXTADDR(RTA_NETMASK, so_mask);

        rtm->rtm_msglen = cp - (char *)&m_rtmsg;

        l = rtm->rtm_msglen;
        rtm->rtm_seq = ++seq;
        rtm->rtm_type = cmd;
        if ((rlen = write(s, (char *)&m_rtmsg, l)) < 0) {
                if ((errno != ESRCH) && !(errno == EEXIST && cmd == RTM_ADD)){
                        report(LOG_WARNING, "writing to routing socket: %s",
                                strerror(errno));
                        return (-1);
                }
        }
        do {
                l = read(s, (char *)&m_rtmsg, sizeof(m_rtmsg));
        } while (l > 0 && (rtm->rtm_type != cmd || rtm->rtm_seq != seq || rtm->rtm_pid != getpid()));
        if (l < 0)
                report(LOG_WARNING, "arp: read from routing socket: %s\n",
                    strerror(errno));
        return (0);
}

#endif /* BSD */
#endif /* BSD >= 199306 */