NetBSD/sys/netinet/ip_gre.c

/*	$NetBSD: ip_gre.c,v 1.1 1998/09/13 20:27:48 hwr Exp $ */

/*
 * (c) 1998 The NetBSD Foundation, Inc.
 * All rights reserved.
 *
 * This code is derived from software contributed to The NetBSD Foundation
 * by Heiko W.Rupp <hwr@pilhuhn.de>
 *
 * 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 NetBSD
 *        Foundation, Inc. and its contributors.
 * 4. Neither the name of The NetBSD Foundation 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 NETBSD FOUNDATION, INC. 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 FOUNDATION 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.
 */

/*
 * deencapsulate GRE packets and send them on
 * output half is in net/ip_gre.[ch]
 *
 */


#include "gre.h"
#if NGRE > 0

#include "opt_inet.h"

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/mbuf.h>
#include <sys/socket.h>
#include <sys/socketvar.h>
#include <sys/protosw.h>
#include <sys/errno.h>
#include <sys/time.h>
#include <sys/kernel.h>
#include <sys/ioctl.h>
#include <sys/syslog.h>
#include <net/ethertypes.h>
#include <net/if.h>
#include <net/netisr.h>
#include <net/route.h>
#include <net/raw_cb.h>

#ifdef INET
#include <netinet/in.h>
#include <netinet/in_var.h>
#include <netinet/in_systm.h>
#include <netinet/ip.h>
#include <netinet/ip_var.h>
#else
Huh? ip_gre input without IP?
#endif

#ifdef NS
#include <netns/ns.h>
#include <netns/ns_if.h>
#endif

#ifdef NETATALK
#include <netatalk/at.h>
#include <netatalk/at_var.h>
#include <netatalk/at_extern.h>
#endif

#include <machine/stdarg.h>

#include "ip_gre.h"
#include <net/if_gre.h>

extern struct gre_softc gre_softc[NGRE];

/*
 * De-encapsulate a packet and feed it back through ip input (this
 * routine is called whenever IP gets a packet with proto type
 * IPPROTO_GRE and a local destination address).
 * This really is simple
 */
void
#if __STDC__
gre_input(struct mbuf *m, ...)
#else
gre_input(m, va_alist)
        struct mbuf *m;
        va_dcl
#endif
{
        register int hlen,ret;
	va_list ap;

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

	ret=gre_input2(m,hlen,IPPROTO_GRE);
	/* 
 	 * ret == 0 : packet not processed, but input from here
	 * means no matching tunnel that is up is found,
	 * so we can just free the mbuf and return
	 */
	if (ret==0)
		m_freem(m);
}

/*
 * decapsulate.
 * Does the real work and is called from gre_input() (above)
 * and also from ipip_input()  (ip_mroute.c)
 * returns 0 if packet is not yet processed 
 * and 1 if it needs no further processing
 * proto is the protocol number of the "calling" foo_input()
 * routine.
 */

int
gre_input2(struct mbuf *m ,int hlen,u_char proto)
{
        register struct ip *ip = mtod(m, struct ip *);
	register struct greip *gip = mtod(m, struct greip *);
        register int s,i;
        register struct ifqueue *ifq;
	struct gre_softc *sc;
	u_short flags;

	i=0;	
	do {
		sc=&gre_softc[i];
		if((sc->g_dst.s_addr == ip->ip_src.s_addr) &&
		    (sc->g_src.s_addr == ip->ip_dst.s_addr))
			break;
		i++;
	} while(i<NGRE);
		  
	if ((i<NGRE) && ((sc->sc_if.if_flags & IFF_UP) == IFF_UP)) {	
		/* found matching tunnel that is up */
		sc->sc_if.if_ipackets++;  
		sc->sc_if.if_ibytes+=m->m_pkthdr.len;
	} else {   /* no matching tunnel or match, but tunnel down */
		return 0;
	}


	switch (proto) {
	case IPPROTO_GRE:
		hlen += sizeof (struct gre_h);

		/* process GRE flags as packet can be of variable len */
		flags = ntohs(gip->gi_flags);

		/* Checksum & Offset are present */
		if ((flags & GRE_CP) | (flags & GRE_RP))
			hlen += 4;
		/* We don't support routing fields (variable length) */
		if (flags & GRE_RP)
			return(0);
		if (flags & GRE_KP)
			hlen += 4;
		if (flags & GRE_SP)
			hlen +=4;

		switch (ntohs(gip->gi_ptype)) { /* ethertypes */
		case ETHERTYPE_IP: /* shouldn't need a schednetisr(), as */
			ifq = &ipintrq;          /* we are in ip_input */
			break;
#ifdef NS
		case ETHERTYPE_NS:
			ifq = &nsintrq;
			schednetisr(NETISR_NS);
			break;
#endif
#ifdef NETATALK
		case ETHERTYPE_AT:
			ifq = &atintrq1;
			schednetisr(NETISR_ATALK);
			break;
#endif
		case ETHERTYPE_IPV6:
			/* FALLTHROUGH */
		default:	   /* others not yet supported */
			return(0);
		}
		break;
	case IPPROTO_IPIP:
		ifq = &ipintrq;
		break;
	default:
		/* others not yet supported */
		return(0);
	}
		

	m->m_data += hlen; 
	m->m_len -= hlen;
	m->m_pkthdr.len -= hlen;

	s = splimp();		/* possible */
	if (IF_QFULL(ifq)) {
		IF_DROP(ifq);
		m_freem(m);
	} else {
		IF_ENQUEUE(ifq,m);
	}
	splx(s);

	return(1);	/* packet is done, no further processing needed */
}



#ifndef MROUTING

/*
 * Well if MROUTING is not defined, the ipip_input function in 
 * ip_mroute.c gets never called, so IPIP packets coming over the
 * tunnel can't be processed. (Not exactly true. They go to raw ip
 * that also can't cope ).
 */

void     
#if __STDC__
gre_ipip_input(struct mbuf *m, ...)
#else    
ipip_input(m, va_alist)
        struct mbuf *m;
        va_dcl
#endif
{
        register int hlen;
	va_list ap;

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

	/*
	 * return == 0 means, that the packet is not preocessed, but
	 * as we are the only ones to decapsulate IPIP, and are not able,
	 * then we can just dump it.
	 */
	if(gre_input2(m,hlen,IPPROTO_IPIP)==0)
		m_freem(m);

}
#endif /* ifndef MROUTING */

#endif /* if NGRE > 0 */