/*	$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);
			}
		}
	}
}