/*
 * 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.
 *
 * $FreeBSD$
 */

/*
 * gif.c
 */

#include "opt_inet.h"
#include "opt_inet6.h"

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/malloc.h>
#include <sys/mbuf.h>
#include <sys/socket.h>
#include <sys/sockio.h>
#include <sys/errno.h>
#include <sys/time.h>
#include <sys/syslog.h>
#include <machine/cpu.h>

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

#ifdef	INET
#include <netinet/in.h>
#include <netinet/in_systm.h>
#include <netinet/in_var.h>
#include <netinet/ip.h>
#include <netinet/in_gif.h>
#endif	/* INET */

#ifdef INET6
#ifndef INET
#include <netinet/in.h>
#endif
#include <netinet6/in6_var.h>
#include <netinet/ip6.h>
#include <netinet6/ip6_var.h>
#include <netinet6/in6_gif.h>
#endif /* INET6 */

#include <net/if_gif.h>

#include "gif.h"

#include <net/net_osdep.h>

void gifattach __P((void *));

/*
 * gif global variable definitions
 */
int ngif = NGIF;		/* number of interfaces */
struct gif_softc *gif = 0;

void
gifattach(dummy)
	void *dummy;
{
	register struct gif_softc *sc;
	register int i;

	gif = sc = malloc (ngif * sizeof(struct gif_softc), M_DEVBUF, M_WAIT);
	bzero(sc, ngif * sizeof(struct gif_softc));
	for (i = 0; i < ngif; sc++, i++) {
		sc->gif_if.if_name = "gif";
		sc->gif_if.if_unit = i;
		sc->gif_if.if_mtu    = GIF_MTU;
		sc->gif_if.if_flags  = IFF_POINTOPOINT | IFF_MULTICAST;
		sc->gif_if.if_ioctl  = gif_ioctl;
		sc->gif_if.if_output = gif_output;
		sc->gif_if.if_type   = IFT_GIF;
		sc->gif_if.if_snd.ifq_maxlen = ifqmaxlen;
		if_attach(&sc->gif_if);
		bpfattach(&sc->gif_if, DLT_NULL, sizeof(u_int));
	}
}

PSEUDO_SET(gifattach, if_gif);

int
gif_output(ifp, m, dst, rt)
	struct ifnet *ifp;
	struct mbuf *m;
	struct sockaddr *dst;
	struct rtentry *rt;	/* added in net2 */
{
	register struct gif_softc *sc = (struct gif_softc*)ifp;
	int error = 0;
	static int called = 0;	/* XXX: MUTEX */
	int calllimit = 10;	/* XXX: adhoc */

	/*
	 * gif may cause infinite recursion calls when misconfigured.
	 * We'll prevent this by introducing upper limit.
	 * XXX: this mechanism may introduce another problem about
	 *      mutual exclusion of the variable CALLED, especially if we
	 *      use kernel thread.
	 */
	if (++called >= calllimit) {
		log(LOG_NOTICE,
		    "gif_output: recursively called too many times(%d)\n",
		    called);
		m_freem(m);
		error = EIO;	/* is there better errno? */
		goto end;
	}
	getmicrotime(&ifp->if_lastchange);
	m->m_flags &= ~(M_BCAST|M_MCAST);
	if (!(ifp->if_flags & IFF_UP) ||
	    sc->gif_psrc == NULL || sc->gif_pdst == NULL) {
		m_freem(m);
		error = ENETDOWN;
		goto end;
	}

	if (ifp->if_bpf) {
		/*
		 * We need to prepend the address family as
		 * a four byte field.  Cons up a dummy header
		 * to pacify bpf.  This is safe because bpf
		 * will only read from the mbuf (i.e., it won't
		 * try to free it or keep a pointer a to it).
		 */
		struct mbuf m0;
		u_int af = dst->sa_family;

		m0.m_next = m;
		m0.m_len = 4;
		m0.m_data = (char *)&af;

		bpf_mtap(ifp, &m0);
	}
	ifp->if_opackets++;
	ifp->if_obytes += m->m_pkthdr.len;

	switch (sc->gif_psrc->sa_family) {
#ifdef INET
	case AF_INET:
		error = in_gif_output(ifp, dst->sa_family, m, rt);
		break;
#endif
#ifdef INET6
	case AF_INET6:
		error = in6_gif_output(ifp, dst->sa_family, m, rt);
		break;
#endif
	default:
		m_freem(m);
		error = ENETDOWN;
	}

  end:
	called = 0;		/* reset recursion counter */
	if (error) ifp->if_oerrors++;
	return error;
}

void
gif_input(m, af, gifp)
	struct mbuf *m;
	int af;
	struct ifnet *gifp;
{
	int s, isr;
	register struct ifqueue *ifq = 0;

	if (gifp == NULL) {
		/* just in case */
		m_freem(m);
		return;
	}

	if (m->m_pkthdr.rcvif)
		m->m_pkthdr.rcvif = gifp;

	if (gifp->if_bpf) {
		/*
		 * We need to prepend the address family as
		 * a four byte field.  Cons up a dummy header
		 * to pacify bpf.  This is safe because bpf
		 * will only read from the mbuf (i.e., it won't
		 * try to free it or keep a pointer a to it).
		 */
		struct mbuf m0;
		u_int af = AF_INET6;

		m0.m_next = m;
		m0.m_len = 4;
		m0.m_data = (char *)&af;

		bpf_mtap(gifp, &m0);
	}

	/*
	 * Put the packet to the network layer input queue according to the
	 * specified address family.
	 * Note: older versions of gif_input directly called network layer
	 * input functions, e.g. ip6_input, here. We changed the policy to
	 * prevent too many recursive calls of such input functions, which
	 * might cause kernel panic. But the change may introduce another
	 * problem; if the input queue is full, packets are discarded.
	 * We believed it rarely occurs and changed the policy. If we find
	 * it occurs more times than we thought, we may change the policy
	 * again.
	 */
	switch (af) {
#ifdef INET
	case AF_INET:
		ifq = &ipintrq;
		isr = NETISR_IP;
		break;
#endif
#ifdef INET6
	case AF_INET6:
		ifq = &ip6intrq;
		isr = NETISR_IPV6;
		break;
#endif
	default:
		m_freem(m);
		return;
	}

	s = splimp();
	if (IF_QFULL(ifq)) {
		IF_DROP(ifq);	/* update statistics */
		m_freem(m);
		splx(s);
		return;
	}
	IF_ENQUEUE(ifq, m);
	/* we need schednetisr since the address family may change */
	schednetisr(isr);
	gifp->if_ipackets++;
	gifp->if_ibytes += m->m_pkthdr.len;
	splx(s);

	return;
}


int
gif_ioctl(ifp, cmd, data)
	struct ifnet *ifp;
	u_long cmd;
	caddr_t data;
{
	struct gif_softc *sc  = (struct gif_softc*)ifp;
	struct ifreq     *ifr = (struct ifreq*)data;
	int error = 0, size;
	struct sockaddr *sa, *dst, *src;

	switch (cmd) {
	case SIOCSIFADDR:
		break;

	case SIOCSIFDSTADDR:
		break;

	case SIOCADDMULTI:
	case SIOCDELMULTI:
		break;

	case SIOCGIFMTU:
		break;
	case SIOCSIFMTU:
		{
			u_long mtu;
			mtu = ifr->ifr_mtu;
			if (mtu < GIF_MTU_MIN || mtu > GIF_MTU_MAX) {
				return (EINVAL);
			}
			ifp->if_mtu = mtu;
		}
		break;

	case SIOCSIFPHYADDR:
#ifdef INET6
	case SIOCSIFPHYADDR_IN6:
#endif /* INET6 */
		switch (ifr->ifr_addr.sa_family) {
#ifdef INET
		case AF_INET:
			src = (struct sockaddr *)
				&(((struct in_aliasreq *)data)->ifra_addr);
			dst = (struct sockaddr *)
				&(((struct in_aliasreq *)data)->ifra_dstaddr);

			/* only one gif can have dst = INADDR_ANY */
#define	satosaddr(sa) (((struct sockaddr_in *)(sa))->sin_addr.s_addr)

			if (satosaddr(dst) == INADDR_ANY) {
				int i;
				struct gif_softc *sc2;

			  	for (i = 0, sc2 = gif; i < ngif; i++, sc2++) {
					if (sc2 == sc) continue;
					if (sc2->gif_pdst &&
					    satosaddr(sc2->gif_pdst)
						== INADDR_ANY) {
					    error = EADDRNOTAVAIL;
					    goto bad;
					}
				}
			}
			size = sizeof(struct sockaddr_in);
			break;
#endif /* INET */
#ifdef INET6
		case AF_INET6:
			src = (struct sockaddr *)
				&(((struct in6_aliasreq *)data)->ifra_addr);
			dst = (struct sockaddr *)
				&(((struct in6_aliasreq *)data)->ifra_dstaddr);

			/* only one gif can have dst = in6addr_any */
#define	satoin6(sa) (&((struct sockaddr_in6 *)(sa))->sin6_addr)

			if (IN6_IS_ADDR_UNSPECIFIED(satoin6(dst))) {
				int i;
				struct gif_softc *sc2;

			  	for (i = 0, sc2 = gif; i < ngif; i++, sc2++) {
					if (sc2 == sc) continue;
					if (sc2->gif_pdst &&
					    IN6_IS_ADDR_UNSPECIFIED(
						satoin6(sc2->gif_pdst)
								    )) {
					    error = EADDRNOTAVAIL;
					    goto bad;
					}
				}
			}
			size = sizeof(struct sockaddr_in6);
			break;
#endif /* INET6 */
		default:
			error = EPROTOTYPE;
			goto bad;
			break;
		}
		if (sc->gif_psrc != NULL)
			free((caddr_t)sc->gif_psrc, M_IFADDR);
		if (sc->gif_pdst != NULL)
			free((caddr_t)sc->gif_pdst, M_IFADDR);

		sa = (struct sockaddr *)malloc(size, M_IFADDR, M_WAITOK);
		bzero((caddr_t)sa, size);
		bcopy((caddr_t)src, (caddr_t)sa, size);
		sc->gif_psrc = sa;

		sa = (struct sockaddr *)malloc(size, M_IFADDR, M_WAITOK);
		bzero((caddr_t)sa, size);
		bcopy((caddr_t)dst, (caddr_t)sa, size);
		sc->gif_pdst = sa;

		ifp->if_flags |= (IFF_UP|IFF_RUNNING);
		if_up(ifp);		/* send up RTM_IFINFO */

		break;

	case SIOCGIFPSRCADDR:
#ifdef INET6
	case SIOCGIFPSRCADDR_IN6:
#endif /* INET6 */
		if (sc->gif_psrc == NULL) {
			error = EADDRNOTAVAIL;
			goto bad;
		}
		src = sc->gif_psrc;
		switch (sc->gif_psrc->sa_family) {
#ifdef INET
		case AF_INET:
			dst = &ifr->ifr_addr;
			size = sizeof(struct sockaddr_in);
			break;
#endif /* INET */
#ifdef INET6
		case AF_INET6:
			dst = (struct sockaddr *)
				&(((struct in6_ifreq *)data)->ifr_addr);
			size = sizeof(struct sockaddr_in6);
			break;
#endif /* INET6 */
		default:
			error = EADDRNOTAVAIL;
			goto bad;
		}
		bcopy((caddr_t)src, (caddr_t)dst, size);
		break;

	case SIOCGIFPDSTADDR:
#ifdef INET6
	case SIOCGIFPDSTADDR_IN6:
#endif /* INET6 */
		if (sc->gif_pdst == NULL) {
			error = EADDRNOTAVAIL;
			goto bad;
		}
		src = sc->gif_pdst;
		switch (sc->gif_pdst->sa_family) {
#ifdef INET
		case AF_INET:
			dst = &ifr->ifr_addr;
			size = sizeof(struct sockaddr_in);
			break;
#endif /* INET */
#ifdef INET6
		case AF_INET6:
			dst = (struct sockaddr *)
				&(((struct in6_ifreq *)data)->ifr_addr);
			size = sizeof(struct sockaddr_in6);
			break;
#endif /* INET6 */
		default:
			error = EADDRNOTAVAIL;
			goto bad;
		}
		bcopy((caddr_t)src, (caddr_t)dst, size);
		break;

	case SIOCSIFFLAGS:
		break;

	default:
		error = EINVAL;
		break;
	}
 bad:
	return error;
}