/*      $OpenBSD: loop-bsd.c,v 1.14 2021/01/26 18:25:07 deraadt Exp $ */

/*
 * Copyright (c) 1993-95 Mats O Jansson.  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 ``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 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 <errno.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#if defined(__bsdi__) || defined(__FreeBSD__)
#include <sys/time.h>
#endif
#include <net/bpf.h>
#include <sys/ioctl.h>

#include "os.h"
#include "common/common.h"
#include "common/mopdef.h"

int
mopOpenRC(struct if_info *p, int trans)
{
#ifndef NORC
        return (*(p->iopen))(p->if_name, O_RDWR, MOP_K_PROTO_RC, trans);
#else
        return (-1);
#endif
}

int
mopOpenDL(struct if_info *p, int trans)
{
#ifndef NODL
        return (*(p->iopen))(p->if_name, O_RDWR, MOP_K_PROTO_DL, trans);
#else
        return (-1);
#endif
}

void
mopReadRC(void)
{
}

void
mopReadDL(void)
{
}

/*
 * The list of all interfaces that are being listened to.  loop()
 * "selects" on the descriptors in this list.
 */
extern struct if_info *iflist;

void   mopProcess(struct if_info *, u_char *);

/*
 * Loop indefinitely listening for MOP requests on the
 * interfaces in 'iflist'.
 */
void
Loop(void)
{
        u_char          *buf, *bp, *ep;
        int              cc;
        fd_set           fds, listeners;
        int              bufsize, maxfd = 0;
        struct if_info  *ii;

        if (iflist == 0) {
                syslog(LOG_ERR, "no interfaces");
                exit(0);
        }
        if (iflist->fd != -1)
                if (ioctl(iflist->fd, BIOCGBLEN, (caddr_t)&bufsize) < 0) {
                        syslog(LOG_ERR, "BIOCGBLEN: %m");
                        exit(0);
                }

        buf = malloc(bufsize);
        if (buf == 0) {
                syslog(LOG_ERR, "malloc: %m");
                exit(0);
        }
        /*
         * Find the highest numbered file descriptor for select().
         * Initialize the set of descriptors to listen to.
         */
        FD_ZERO(&fds);
        for (ii = iflist; ii; ii = ii->next)
                if (ii->fd != -1) {
                        FD_SET(ii->fd, &fds);
                        if (ii->fd > maxfd)
                                maxfd = ii->fd;
                }

        while (1) {
                listeners = fds;
                if (select(maxfd + 1, &listeners, NULL, NULL, NULL) < 0) {
                        syslog(LOG_ERR, "select: %m");
                        exit(0);
                }
                for (ii = iflist; ii; ii = ii->next)
                        if (ii->fd != -1) {
                                if (!FD_ISSET(ii->fd, &listeners))
                                        continue;
again:
                        cc = read(ii->fd, buf, bufsize);
                        /* Don't choke when we get ptraced */
                        if (cc < 0 && errno == EINTR)
                                goto again;
                        /* Due to a SunOS bug, after 2^31 bytes, the file
                         * offset overflows and read fails with EINVAL.  The
                         * lseek() to 0 will fix things. */
                        if (cc < 0) {
                                if (errno == EINVAL && (lseek(ii->fd, 0,
                                    SEEK_CUR) + bufsize) < 0) {
                                        lseek(ii->fd, 0, SEEK_SET);
                                        goto again;
                                }
                                syslog(LOG_ERR, "read: %m");
                                exit(0);
                        }
                        /* Loop through the packet(s) */
#define bhp ((struct bpf_hdr *)bp)
                        bp = buf;
                        ep = bp + cc;
                        while (bp < ep) {
                                int caplen, hdrlen;

                                caplen = bhp->bh_caplen;
                                hdrlen = bhp->bh_hdrlen;
                                mopProcess(ii, bp + hdrlen);
                                bp += BPF_WORDALIGN(hdrlen + caplen);
                        }
                }
        }
}