/*-
 * Copyright (c) 1984, 1985, 1986, 1987, 1993
 *	The Regents of the University of California.  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.
 * 4. 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.
 *
 * Copyright (c) 1995, Mike Mitchell
 *
 * 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. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *	This product includes software developed by the University of
 *	California, Berkeley and its contributors.
 * 4. 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.
 *
 *	@(#)ipx_ip.c
 */

#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");

/*
 * Software interface driver for encapsulating IPX in IP.
 */

#include "opt_inet.h"
#include "opt_ipx.h"

#ifndef INET
#error The option IPXIP requires option INET.
#endif

#include <sys/param.h>
#include <sys/kernel.h>
#include <sys/systm.h>
#include <sys/malloc.h>
#include <sys/mbuf.h>
#include <sys/protosw.h>
#include <sys/socket.h>
#include <sys/socketvar.h>
#include <sys/sockio.h>

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

#include <netinet/in.h>
#include <netinet/in_systm.h>
#include <netinet/in_var.h>
#include <netinet/ip.h>
#include <netinet/ip_var.h>
#include <netinet/ip_options.h>

#include <netipx/ipx.h>
#include <netipx/ipx_if.h>
#include <netipx/ipx_ip.h>
#include <netipx/ipx_var.h>

NET_NEEDS_GIANT("ipx_ip");

static struct ifnet	 ipxipif;
static int		 ipxipif_units;

/* List of all hosts and gateways or broadcast addrs. */
static struct ifnet_en	*ipxip_list;

static struct ifreq	 ifr_ipxip = {"ipxip0"};
static struct mbuf	*ipxip_badlen;
static struct mbuf	*ipxip_lastin;
static int		 ipxip_hold_input;

static struct ifnet_en	*ipxipattach(void);
static int		 ipxip_free(struct ifnet *ifp);
static int		 ipxipioctl(struct ifnet *ifp, u_long cmd,
			    caddr_t data);
static int		 ipxipoutput(struct ifnet *ifp, struct mbuf *m,
			    struct sockaddr *dst, struct rtentry *rt);
static void		 ipxip_rtchange(struct in_addr *dst);
static void		 ipxipstart(struct ifnet *ifp);

static struct ifnet_en *
ipxipattach(void)
{
	struct ifnet_en *m;
	struct ifnet *ifp;

	if (ipxipif.if_mtu == 0) {
		ifp = &ipxipif;
		if_initname(ifp, "ipxip", ipxipif_units);
		ifp->if_mtu = LOMTU;
		ifp->if_ioctl = ipxipioctl;
		ifp->if_output = ipxipoutput;
		ifp->if_start = ipxipstart;
		ifp->if_flags = IFF_POINTOPOINT;
	}

	MALLOC((m), struct ifnet_en *, sizeof(*m), M_PCB, M_NOWAIT | M_ZERO);
	if (m == NULL)
		return (NULL);
	m->ifen_next = ipxip_list;
	ipxip_list = m;
	ifp = m->ifen_ifp = if_alloc(IFT_IPXIP);
	if (ifp == NULL) {
		FREE(m, M_PCB);
		return (NULL);
	}

	if_initname(ifp, "ipxip", ipxipif_units++);
	ifp->if_mtu = LOMTU;
	ifp->if_ioctl = ipxipioctl;
	ifp->if_output = ipxipoutput;
	ifp->if_start = ipxipstart;
	ifp->if_flags = IFF_POINTOPOINT;
	ifp->if_softc = m;
	if_attach(ifp);

	return (m);
}

/*
 * Process an ioctl request.
 */
static int
ipxipioctl(struct ifnet *ifp, u_long cmd, caddr_t data)
{
	int error = 0;
	struct ifreq *ifr;

	switch (cmd) {
	case SIOCSIFADDR:
		ifp->if_flags |= IFF_UP;
		/* FALLTHROUGH */

	case SIOCSIFDSTADDR:
		/*
		 * Everything else is done at a higher level.
		 */
		break;

	case SIOCSIFFLAGS:
		ifr = (struct ifreq *)data;
		if ((ifr->ifr_flags & IFF_UP) == 0)
			error = ipxip_free(ifp);
		break;

	default:
		error = EINVAL;
	}
	return (error);
}

void
ipxip_input(struct mbuf *m, int hlen)
{
	struct ip *ip;
	struct ipx *ipx;
	int len, s;

	if (ipxip_hold_input) {
		if (ipxip_lastin != NULL)
			m_freem(ipxip_lastin);
		ipxip_lastin = m_copym(m, 0, (int)M_COPYALL, M_DONTWAIT);
	}

	/*
	 * Get IP and IPX header together in first mbuf.
	 */
	ipxipif.if_ipackets++;
	s = sizeof(struct ip) + sizeof(struct ipx);
	if (((m->m_flags & M_EXT) || m->m_len < s) &&
	    (m = m_pullup(m, s)) == NULL) {
		ipxipif.if_ierrors++;
		return;
	}
	ip = mtod(m, struct ip *);
	if (ip->ip_hl > (sizeof(struct ip) >> 2)) {
		ip_stripoptions(m, (struct mbuf *)NULL);
		if (m->m_len < s) {
			if ((m = m_pullup(m, s)) == NULL) {
				ipxipif.if_ierrors++;
				return;
			}
			ip = mtod(m, struct ip *);
		}
	}

	/*
	 * Make mbuf data length reflect IPX length.  If not enough data to
	 * reflect IPX length, drop.
	 */
	m->m_data += sizeof(struct ip);
	m->m_len -= sizeof(struct ip);
	m->m_pkthdr.len -= sizeof(struct ip);
	ipx = mtod(m, struct ipx *);
	len = ntohs(ipx->ipx_len);
	if (len & 1)
		len++;		/* Preserve Garbage Byte */
	if (ip->ip_len != len) {
		if (len > ip->ip_len) {
			ipxipif.if_ierrors++;
			if (ipxip_badlen)
				m_freem(ipxip_badlen);
			ipxip_badlen = m;
			return;
		}
		/*
		 * Any extra will be trimmed off by the IPX routines.
		 */
	}

	/*
	 * Deliver to IPX.
	 */
	netisr_dispatch(NETISR_IPX, m);
}

static int
ipxipoutput(struct ifnet *ifp, struct mbuf *m, struct sockaddr *dst,
    struct rtentry *rt)
{
	struct ifnet_en *ifn = (struct ifnet_en *)ifp->if_softc;
	struct route *ro = &(ifn->ifen_route);
	struct ipx *ipx = mtod(m, struct ipx *);
	struct ip *ip;
	int len = 0;
	int error;

	ifn->ifen_ifp->if_opackets++;
	ipxipif.if_opackets++;

	/*
	 * Calculate data length and make space for IP header.
	 */
	len =  ntohs(ipx->ipx_len);
	if (len & 1)
		len++;		/* Preserve Garbage Byte */

	/*
	 * Following clause not necessary on VAX.
	 */
	if (3 & (intptr_t)m->m_data) {
		/* force longword alignment of ip hdr */
		struct mbuf *m0 = m_gethdr(MT_DATA, M_DONTWAIT);
		if (m0 == NULL) {
			m_freem(m);
			return (ENOBUFS);
		}
		MH_ALIGN(m0, sizeof(struct ip));
		m0->m_flags = m->m_flags & M_COPYFLAGS;
		m0->m_next = m;
		m0->m_len = sizeof(struct ip);
		m0->m_pkthdr.len = m0->m_len + m->m_len;
		m->m_flags &= ~M_PKTHDR;
		m = m0;
	} else {
		M_PREPEND(m, sizeof(struct ip), M_DONTWAIT);
		if (m == NULL)
			return (ENOBUFS);
	}

	/*
	 * Fill in IP header.
	 */
	ip = mtod(m, struct ip *);
	*(long *)ip = 0;
	ip->ip_p = IPPROTO_IDP;
	ip->ip_src = ifn->ifen_src;
	ip->ip_dst = ifn->ifen_dst;
	ip->ip_len = (u_short)len + sizeof(struct ip);
	ip->ip_ttl = MAXTTL;

	/*
	 * Output final datagram.
	 */
	error =  ip_output(m, (struct mbuf *)NULL, ro, SO_BROADCAST, NULL,
	    NULL);
	if (error) {
		ifn->ifen_ifp->if_oerrors++;
		ifn->ifen_ifp->if_ierrors = error;
	}
	return (error);
}

static void
ipxipstart(struct ifnet *ifp)
{

	panic("ipxip_start called\n");
}

int
ipxip_route(struct socket *so, struct sockopt *sopt)
{
	struct in_ifaddr *ia;
	struct ifnet_en *ifn;
	struct sockaddr_in *src;
	struct ipxip_req rq;
	struct sockaddr_ipx *ipx_dst;
	struct sockaddr_in *ip_dst;
	struct ifnet *ifp;
	struct route ro;
	int error;

	error = sooptcopyin(sopt, &rq, sizeof rq, sizeof rq);
	if (error)
		return (error);
	ipx_dst = (struct sockaddr_ipx *)&rq.rq_ipx;
	ip_dst = (struct sockaddr_in *)&rq.rq_ip;

	/*
	 * First, make sure we already have an IPX address:
	 */
	if (ipx_ifaddr == NULL)
		return (EADDRNOTAVAIL);

	/*
	 * Now, determine if we can get to the destination.
	 */
	bzero((caddr_t)&ro, sizeof(ro));
	ro.ro_dst = *(struct sockaddr *)ip_dst;
	rtalloc_ign(&ro, 0);
	if (ro.ro_rt == NULL || ro.ro_rt->rt_ifp == NULL)
		return (ENETUNREACH);

	/*
	 * And see how he's going to get back to us: i.e., what return IP
	 * address do we use?
	 */
	ifp = ro.ro_rt->rt_ifp;
	for (ia = TAILQ_FIRST(&in_ifaddrhead); ia != NULL;
	     ia = TAILQ_NEXT(ia, ia_link))
		if (ia->ia_ifp == ifp)
			break;
	if (ia == NULL)
		ia = TAILQ_FIRST(&in_ifaddrhead);
	if (ia == NULL) {
		RTFREE(ro.ro_rt);
		return (EADDRNOTAVAIL);
	}
	src = (struct sockaddr_in *)&ia->ia_addr;

	/*
	 * Is there a free (pseudo-)interface or space?
	 */
	for (ifn = ipxip_list; ifn != NULL; ifn = ifn->ifen_next) {
		if ((ifn->ifen_ifp->if_flags & IFF_UP) == 0)
			break;
	}
	if (ifn == NULL)
		ifn = ipxipattach();
	if (ifn == NULL) {
		RTFREE(ro.ro_rt);
		return (ENOBUFS);
	}
	ifn->ifen_route = ro;
	ifn->ifen_dst =  ip_dst->sin_addr;
	ifn->ifen_src = src->sin_addr;

	/*
	 * Now configure this as a point to point link.
	 */
	ifr_ipxip.ifr_name[4] = '0' + ipxipif_units - 1;
	ifr_ipxip.ifr_dstaddr = *(struct sockaddr *)ipx_dst;
	ipx_control(so, (int)SIOCSIFDSTADDR, (caddr_t)&ifr_ipxip,
			(struct ifnet *)ifn, sopt->sopt_td);

	/*
	 * Use any of our addresses.
	 */
	satoipx_addr(ifr_ipxip.ifr_addr).x_host =
	    ipx_ifaddr->ia_addr.sipx_addr.x_host;

	return (ipx_control(so, (int)SIOCSIFADDR, (caddr_t)&ifr_ipxip,
	    (struct ifnet *)ifn, sopt->sopt_td));
}

static int
ipxip_free(struct ifnet *ifp)
{
	struct ifnet_en *ifn = (struct ifnet_en *)ifp->if_softc;
	struct route *ro = & ifn->ifen_route;

	if (ro->ro_rt != NULL) {
		RTFREE(ro->ro_rt);
		ro->ro_rt = NULL;
	}
	ifp->if_flags &= ~IFF_UP;
	return (0);
}

void
ipxip_ctlinput(int cmd, struct sockaddr *sa, void *dummy)
{
	struct sockaddr_in *sin;

	if ((unsigned)cmd >= PRC_NCMDS)
		return;
	if (sa->sa_family != AF_INET && sa->sa_family != AF_IMPLINK)
		return;
	sin = (struct sockaddr_in *)sa;
	if (sin->sin_addr.s_addr == INADDR_ANY)
		return;

	switch (cmd) {
	case PRC_ROUTEDEAD:
	case PRC_REDIRECT_NET:
	case PRC_REDIRECT_HOST:
	case PRC_REDIRECT_TOSNET:
	case PRC_REDIRECT_TOSHOST:
		ipxip_rtchange(&sin->sin_addr);
		break;
	}
}

static void
ipxip_rtchange(struct in_addr *dst)
{
	struct ifnet_en *ifn;

	for (ifn = ipxip_list; ifn != NULL; ifn = ifn->ifen_next) {
		if (ifn->ifen_dst.s_addr == dst->s_addr &&
			ifn->ifen_route.ro_rt != NULL) {
				RTFREE(ifn->ifen_route.ro_rt);
				ifn->ifen_route.ro_rt = NULL;
		}
	}
}