/*
 * $FreeBSD: src/sys/netinet/in_gif.c,v 1.5.2.11 2003/01/23 21:06:45 sam Exp $
 * $KAME: in_gif.c,v 1.54 2001/05/14 14:02:16 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.
 */

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

#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/kernel.h>
#include <sys/sysctl.h>
#include <sys/protosw.h>

#include <sys/malloc.h>

#include <machine/stdarg.h>

#include <net/if.h>
#include <net/route.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/in_var.h>
#include <netinet/ip_encap.h>
#include <netinet/ip_ecn.h>

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

#include <net/gif/if_gif.h>     
#include <net/net_osdep.h>

#ifdef INET
static int gif_validate4 (const struct ip *, struct gif_softc *,
                          struct ifnet *);

extern  struct domain inetdomain;
const struct protosw in_gif_protosw =
    {
        .pr_type = SOCK_RAW,
        .pr_domain = &inetdomain,
        .pr_protocol = 0 /*IPPROTO_IPV[46]*/,
        .pr_flags = PR_ATOMIC|PR_ADDR,

        .pr_input = in_gif_input,
        .pr_output = rip_output,
        .pr_ctlinput = NULL,
        .pr_ctloutput = rip_ctloutput,

        .pr_ctlport = NULL,
        .pr_usrreqs = &rip_usrreqs
    };

int ip_gif_ttl = GIF_TTL;
SYSCTL_INT(_net_inet_ip, IPCTL_GIF_TTL, gifttl, CTLFLAG_RW,
        &ip_gif_ttl, 0, "TTL of GIF packet");

int
in_gif_output(struct ifnet *ifp, int family, struct mbuf *m)
{
        struct gif_softc *sc = (struct gif_softc*)ifp;
        struct route *ro = &sc->gif_ro[mycpu->gd_cpuid];
        struct sockaddr_in *dst = (struct sockaddr_in *)&ro->ro_dst;
        struct sockaddr_in *sin_src = (struct sockaddr_in *)sc->gif_psrc;
        struct sockaddr_in *sin_dst = (struct sockaddr_in *)sc->gif_pdst;
        struct ip iphdr;        /* capsule IP header, host byte ordered */
        int proto, error;
        u_int8_t tos;

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

        switch (family) {
#ifdef INET
        case AF_INET:
            {
                struct ip *ip;

                proto = IPPROTO_IPV4;
                if (m->m_len < sizeof *ip) {
                        m = m_pullup(m, sizeof *ip);
                        if (!m)
                                return ENOBUFS;
                }
                ip = mtod(m, struct ip *);
                tos = ip->ip_tos;
                break;
            }
#endif
#ifdef INET6
        case AF_INET6:
            {
                struct ip6_hdr *ip6;
                proto = IPPROTO_IPV6;
                if (m->m_len < sizeof *ip6) {
                        m = m_pullup(m, sizeof *ip6);
                        if (!m)
                                return ENOBUFS;
                }
                ip6 = mtod(m, struct ip6_hdr *);
                tos = (ntohl(ip6->ip6_flow) >> 20) & 0xff;
                break;
            }
#endif
        default:
#ifdef DEBUG
                kprintf("in_gif_output: warning: unknown family %d passed\n",
                        family);
#endif
                m_freem(m);
                return EAFNOSUPPORT;
        }

        bzero(&iphdr, sizeof iphdr);
        iphdr.ip_src = sin_src->sin_addr;
        /* bidirectional configured tunnel mode */
        if (sin_dst->sin_addr.s_addr != INADDR_ANY)
                iphdr.ip_dst = sin_dst->sin_addr;
        else {
                m_freem(m);
                return ENETUNREACH;
        }
        iphdr.ip_p = proto;
        /* version will be set in ip_output() */
        iphdr.ip_ttl = ip_gif_ttl;
        iphdr.ip_len = htons(m->m_pkthdr.len + sizeof(struct ip));
        if (ifp->if_flags & IFF_LINK1)
                ip_ecn_ingress(ECN_ALLOWED, &iphdr.ip_tos, &tos);
        else
                ip_ecn_ingress(ECN_NOCARE, &iphdr.ip_tos, &tos);

        /* prepend new IP header */
        M_PREPEND(m, sizeof(struct ip), M_NOWAIT);
        if (m && m->m_len < sizeof(struct ip))
                m = m_pullup(m, sizeof(struct ip));
        if (m == NULL) {
                kprintf("ENOBUFS in in_gif_output %d\n", __LINE__);
                return ENOBUFS;
        }
        bcopy(&iphdr, mtod(m, struct ip *), sizeof(struct ip));

        if (dst->sin_family != sin_dst->sin_family ||
            dst->sin_addr.s_addr != sin_dst->sin_addr.s_addr) {
                /* cache route doesn't match */
                dst->sin_family = sin_dst->sin_family;
                dst->sin_len = sizeof(struct sockaddr_in);
                dst->sin_addr = sin_dst->sin_addr;
                if (ro->ro_rt != NULL) {
                        RTFREE(ro->ro_rt);
                        ro->ro_rt = NULL;
                }
#if 0
                sc->gif_if.if_mtu = GIF_MTU;
#endif
        }

        if (ro->ro_rt == NULL) {
                rtalloc(ro);
                if (ro->ro_rt == NULL) {
                        m_freem(m);
                        return ENETUNREACH;
                }

                /* if it constitutes infinite encapsulation, punt. */
                if (ro->ro_rt->rt_ifp == ifp) {
                        m_freem(m);
                        return ENETUNREACH;     /* XXX */
                }
#if 0
                ifp->if_mtu = ro->ro_rt->rt_ifp->if_mtu - sizeof(struct ip);
#endif
        }

        error = ip_output(m, NULL, ro, 0, NULL, NULL);
        return(error);
}

int
in_gif_input(struct mbuf **mp, int *offp, int proto)
{
        struct mbuf *m = *mp;
        struct ifnet *gifp = NULL;
        struct ip *ip;
        int af;
        u_int8_t otos;
        int off;

        off = *offp;
        *mp = NULL;

        ip = mtod(m, struct ip *);

        gifp = (struct ifnet *)encap_getarg(m);

        if (gifp == NULL || (gifp->if_flags & IFF_UP) == 0) {
                m_freem(m);
                ipstat.ips_nogif++;
                return(IPPROTO_DONE);
        }

        otos = ip->ip_tos;
        m_adj(m, off);

        switch (proto) {
#ifdef INET
        case IPPROTO_IPV4:
            {
                struct ip *ip;
                af = AF_INET;
                if (m->m_len < sizeof *ip) {
                        m = m_pullup(m, sizeof *ip);
                        if (!m)
                                return(IPPROTO_DONE);
                }
                ip = mtod(m, struct ip *);
                if (gifp->if_flags & IFF_LINK1)
                        ip_ecn_egress(ECN_ALLOWED, &otos, &ip->ip_tos);
                else
                        ip_ecn_egress(ECN_NOCARE, &otos, &ip->ip_tos);
                break;
            }
#endif
#ifdef INET6
        case IPPROTO_IPV6:
            {
                struct ip6_hdr *ip6;
                u_int8_t itos;
                af = AF_INET6;
                if (m->m_len < sizeof *ip6) {
                        m = m_pullup(m, sizeof *ip6);
                        if (!m)
                                return(IPPROTO_DONE);
                }
                ip6 = mtod(m, struct ip6_hdr *);
                itos = (ntohl(ip6->ip6_flow) >> 20) & 0xff;
                if (gifp->if_flags & IFF_LINK1)
                        ip_ecn_egress(ECN_ALLOWED, &otos, &itos);
                else
                        ip_ecn_egress(ECN_NOCARE, &otos, &itos);
                ip6->ip6_flow &= ~htonl(0xff << 20);
                ip6->ip6_flow |= htonl((u_int32_t)itos << 20);
                break;
            }
#endif /* INET6 */
        default:
                ipstat.ips_nogif++;
                m_freem(m);
                return(IPPROTO_DONE);
        }
        gif_input(m, af, gifp);
        return(IPPROTO_DONE);
}

/*
 * validate outer address.
 */
static int
gif_validate4(const struct ip *ip, struct gif_softc *sc, struct ifnet *ifp)
{
        struct sockaddr_in *src, *dst;
        struct in_ifaddr_container *iac;

        src = (struct sockaddr_in *)sc->gif_psrc;
        dst = (struct sockaddr_in *)sc->gif_pdst;

        /* check for address match */
        if (src->sin_addr.s_addr != ip->ip_dst.s_addr ||
            dst->sin_addr.s_addr != ip->ip_src.s_addr)
                return 0;

        /* martian filters on outer source - NOT done in ip_input! */
        if (IN_MULTICAST(ntohl(ip->ip_src.s_addr)))
                return 0;
        switch ((ntohl(ip->ip_src.s_addr) & 0xff000000) >> 24) {
        case 0: case 127: case 255:
                return 0;
        }
        /* reject packets with broadcast on source */
        TAILQ_FOREACH(iac, &in_ifaddrheads[mycpuid], ia_link) {
                struct in_ifaddr *ia4 = iac->ia;

                if (!(ia4->ia_ifa.ifa_ifp->if_flags & IFF_BROADCAST))
                        continue;
                if (ip->ip_src.s_addr == ia4->ia_broadaddr.sin_addr.s_addr)
                        return 0;
        }

        /* ingress filters on outer source */
        if (!(sc->gif_if.if_flags & IFF_LINK2) && ifp != NULL) {
                struct sockaddr_in sin;
                struct rtentry *rt;

                bzero(&sin, sizeof sin);
                sin.sin_family = AF_INET;
                sin.sin_len = sizeof(struct sockaddr_in);
                sin.sin_addr = ip->ip_src;
                rt = rtpurelookup((struct sockaddr *)&sin);
                if (rt != NULL)
                        --rt->rt_refcnt;
                if (rt == NULL || rt->rt_ifp != ifp) {
#if 0
                        log(LOG_WARNING, "%s: packet from 0x%x dropped "
                            "due to ingress filter\n", if_name(&sc->gif_if),
                            (u_int32_t)ntohl(sin.sin_addr.s_addr));
#endif
                        return 0;
                }
        }

        return 32 * 2;
}

/*
 * we know that we are in IFF_UP, outer address available, and outer family
 * matched the physical addr family.  see gif_encapcheck().
 */
int
gif_encapcheck4(const struct mbuf *m, int off, int proto, void *arg)
{
        struct ip ip;
        struct gif_softc *sc;
        struct ifnet *ifp;

        /* sanity check done in caller */
        sc = (struct gif_softc *)arg;

        /* LINTED const cast */
        m_copydata(__DECONST(struct mbuf *, m), 0, sizeof ip, &ip);
        ifp = ((m->m_flags & M_PKTHDR) != 0) ? m->m_pkthdr.rcvif : NULL;

        return gif_validate4(&ip, sc, ifp);
}

int
in_gif_attach(struct gif_softc *sc)
{
        sc->encap_cookie4 = encap_attach_func(AF_INET, -1, gif_encapcheck,
            &in_gif_protosw, sc);
        if (sc->encap_cookie4 == NULL)
                return EEXIST;
        return 0;
}

int
in_gif_detach(struct gif_softc *sc)
{
        int error;

        error = encap_detach(sc->encap_cookie4);
        if (error == 0)
                sc->encap_cookie4 = NULL;
        return error;
}

#endif /* INET */