/*	$OpenBSD: in_gif.c,v 1.8 2000/02/07 06:18:44 itojun Exp $	*/

/*
 * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
 * 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.
 * 3. Neither the name of the project 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 PROJECT 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 PROJECT 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.
 */

/*
 * in_gif.c
 */

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/socket.h>
#include <sys/sockio.h>
#include <sys/mbuf.h>
#include <sys/errno.h>
#include <sys/ioctl.h>
#include <sys/protosw.h>

#include <net/if.h>
#include <net/route.h>
#include <net/if_gif.h>

#include <netinet/in.h>
#include <netinet/in_systm.h>
#include <netinet/ip.h>
#include <netinet/ip_var.h>
#include <netinet/in_gif.h>
#include <netinet/ip_ecn.h>
#include <netinet/ip_ipsp.h>

#ifdef INET6
#include <netinet/ip6.h>
#endif

#ifdef MROUTING
#include <netinet/ip_mroute.h>
#endif /* MROUTING */

#include <net/if_gif.h>	

#include "gif.h"

#include <machine/stdarg.h>

#include <net/net_osdep.h>

#if NGIF > 0
int ip_gif_ttl = GIF_TTL;
#else
int ip_gif_ttl = 0;
#endif

#ifndef offsetof
#define offsetof(s, e) ((int)&((s *)0)->e)
#endif

int
in_gif_output(ifp, family, m, rt)
	struct ifnet	*ifp;
	int		family;
	struct mbuf	*m;
	struct rtentry *rt;
{
	register struct gif_softc *sc = (struct gif_softc*)ifp;
	struct sockaddr_in *sin_src = (struct sockaddr_in *)sc->gif_psrc;
	struct sockaddr_in *sin_dst = (struct sockaddr_in *)sc->gif_pdst;
	struct tdb tdb;
	struct xformsw xfs;
	int error;
	int hlen, poff;
	u_int16_t plen;
	struct mbuf *mp;

	if (sin_src == NULL || sin_dst == NULL ||
	    sin_src->sin_family != AF_INET ||
	    sin_dst->sin_family != AF_INET) {
		m_freem(m);
		return EAFNOSUPPORT;
	}

	/* multi-destination mode is not supported */
	if (ifp->if_flags & IFF_LINK0) {
		m_freem(m);
		return ENETUNREACH;
	}

	/* setup dummy tdb.  it highly depends on ipipoutput() code. */
	bzero(&tdb, sizeof(tdb));
	bzero(&xfs, sizeof(xfs));
	tdb.tdb_src.sin.sin_family = AF_INET;
	tdb.tdb_src.sin.sin_len = sizeof(struct sockaddr_in);
	tdb.tdb_src.sin.sin_addr = sin_src->sin_addr;
	tdb.tdb_dst.sin.sin_family = AF_INET;
	tdb.tdb_dst.sin.sin_len = sizeof(struct sockaddr_in);
	tdb.tdb_dst.sin.sin_addr = sin_dst->sin_addr;
	tdb.tdb_xform = &xfs;
	xfs.xf_type = -1;	/* not XF_IP4 */

	switch (family) {
	case AF_INET:
		if (m->m_len < sizeof(struct ip)) {
			m = m_pullup(m, sizeof(struct ip));
			if (m == NULL)
				return ENOBUFS;
		}
		hlen = (mtod(m, struct ip *)->ip_hl) << 2;
		poff = offsetof(struct ip, ip_p);
		break;
#ifdef INET6
	case AF_INET6:
		hlen = sizeof(struct ip6_hdr);
		poff = offsetof(struct ip6_hdr, ip6_nxt);
		break;
#endif
	default:
#ifdef DEBUG
	        printf("in_gif_output: warning: unknown family %d passed\n",
			family);
#endif
		m_freem(m);
		return EAFNOSUPPORT;
	}

	/* encapsulate into IPv4 packet */
	mp = NULL;
	error = ipip_output(m, &tdb, &mp, hlen, poff);
	if (error)
		return error;
	else if (mp == NULL)
		return EFAULT;

	m = mp;

	/* ip_output needs host-order length.  it should be nuked */
	m_copydata(m, offsetof(struct ip, ip_len), sizeof(u_int16_t),
		   (caddr_t) &plen);
	NTOHS(plen);
	m_copyback(m, offsetof(struct ip, ip_len), sizeof(u_int16_t),
		   (caddr_t) &plen);

	return ip_output(m, NULL, NULL, 0, NULL, NULL);
}

void
#if __STDC__
in_gif_input(struct mbuf *m, ...)
#else
in_gif_input(m, va_alist)
	struct mbuf *m;
	va_dcl
#endif
{
	int off;
	struct gif_softc *sc;
	struct ifnet *gifp = NULL;
	struct ip *ip;
	int i;
	va_list ap;

	va_start(ap, m);
	off = va_arg(ap, int);
	va_end(ap);

	/* XXX what if we run transport-mode IPsec to protect gif tunnel ? */
	if (m->m_flags & (M_AUTH | M_CONF))
		goto inject;

	ip = mtod(m, struct ip *);

	/* this code will be soon improved. */
#define	satosin(sa)	((struct sockaddr_in *)(sa))	
	for (i = 0, sc = gif; i < ngif; i++, sc++) {
		if (sc->gif_psrc == NULL
		 || sc->gif_pdst == NULL
		 || sc->gif_psrc->sa_family != AF_INET
		 || sc->gif_pdst->sa_family != AF_INET) {
			continue;
		}

		if ((sc->gif_if.if_flags & IFF_UP) == 0)
			continue;

		if ((sc->gif_if.if_flags & IFF_LINK0)
		 && satosin(sc->gif_psrc)->sin_addr.s_addr == ip->ip_dst.s_addr
		 && satosin(sc->gif_pdst)->sin_addr.s_addr == INADDR_ANY) {
			gifp = &sc->gif_if;
			continue;
		}

		if (satosin(sc->gif_psrc)->sin_addr.s_addr ==
		    ip->ip_dst.s_addr
		 && satosin(sc->gif_pdst)->sin_addr.s_addr ==
		    ip->ip_src.s_addr)
		{
			gifp = &sc->gif_if;
			break;
		}
	}

	if (gifp) {
		m->m_pkthdr.rcvif = gifp;
		ipip_input(m, off); /* We have a configured GIF */
		return;
	}

inject:
	ip4_input(m, off); /* No GIF interface was configured */
	return;
}