4.4BSD/usr/src/sys/netinet/ip_mroute.c
/*
* Copyright (c) 1989 Stephen Deering
* Copyright (c) 1992, 1993
* The Regents of the University of California. All rights reserved.
*
* This code is derived from software contributed to Berkeley by
* Stephen Deering of Stanford University.
*
* 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.
*
* @(#)ip_mroute.c 8.1 (Berkeley) 6/10/93
*/
/*
* Procedures for the kernel part of DVMRP,
* a Distance-Vector Multicast Routing Protocol.
* (See RFC-1075.)
*
* Written by David Waitzman, BBN Labs, August 1988.
* Modified by Steve Deering, Stanford, February 1989.
*
* MROUTING 1.1
*/
#ifndef MROUTING
int ip_mrtproto; /* for netstat only */
#else
#include <sys/param.h>
#include <sys/errno.h>
#include <sys/ioctl.h>
#include <sys/malloc.h>
#include <sys/mbuf.h>
#include <sys/protosw.h>
#include <sys/socket.h>
#include <sys/socketvar.h>
#include <sys/time.h>
#include <net/af.h>
#include <net/if.h>
#include <net/route.h>
#include <net/raw_cb.h>
#include <netinet/in.h>
#include <netinet/in_systm.h>
#include <netinet/ip.h>
#include <netinet/in_pcb.h>
#include <netinet/in_var.h>
#include <netinet/ip_var.h>
#include <netinet/igmp.h>
#include <netinet/igmp_var.h>
#include <netinet/ip_mroute.h>
/* Static forwards */
static int ip_mrouter_init __P((struct socket *));
static int add_vif __P((struct vifctl *));
static int del_vif __P((vifi_t *vifip));
static int add_lgrp __P((struct lgrplctl *));
static int del_lgrp __P((struct lgrplctl *));
static int grplst_member __P((struct vif *, struct in_addr));
static u_long nethash __P((struct in_addr in));
static int add_mrt __P((struct mrtctl *));
static int del_mrt __P((struct in_addr *));
static struct mrt *mrtfind __P((struct in_addr));
static void phyint_send __P((struct mbuf *, struct vif *));
static void tunnel_send __P((struct mbuf *, struct vif *));
#define INSIZ sizeof(struct in_addr)
#define same(a1, a2) (bcmp((caddr_t)(a1), (caddr_t)(a2), INSIZ) == 0)
#define satosin(sa) ((struct sockaddr_in *)(sa))
/*
* Globals. All but ip_mrouter and ip_mrtproto could be static,
* except for netstat or debugging purposes.
*/
struct socket *ip_mrouter = NULL;
int ip_mrtproto = IGMP_DVMRP; /* for netstat only */
struct mrt *mrttable[MRTHASHSIZ];
struct vif viftable[MAXVIFS];
struct mrtstat mrtstat;
/*
* Private variables.
*/
static vifi_t numvifs = 0;
static struct mrt *cached_mrt = NULL;
static u_long cached_origin;
static u_long cached_originmask;
/*
* Handle DVMRP setsockopt commands to modify the multicast routing tables.
*/
int
ip_mrouter_cmd(cmd, so, m)
register int cmd;
register struct socket *so;
register struct mbuf *m;
{
register int error = 0;
if (cmd != DVMRP_INIT && so != ip_mrouter)
error = EACCES;
else switch (cmd) {
case DVMRP_INIT:
error = ip_mrouter_init(so);
break;
case DVMRP_DONE:
error = ip_mrouter_done();
break;
case DVMRP_ADD_VIF:
if (m == NULL || m->m_len < sizeof(struct vifctl))
error = EINVAL;
else
error = add_vif(mtod(m, struct vifctl *));
break;
case DVMRP_DEL_VIF:
if (m == NULL || m->m_len < sizeof(short))
error = EINVAL;
else
error = del_vif(mtod(m, vifi_t *));
break;
case DVMRP_ADD_LGRP:
if (m == NULL || m->m_len < sizeof(struct lgrplctl))
error = EINVAL;
else
error = add_lgrp(mtod(m, struct lgrplctl *));
break;
case DVMRP_DEL_LGRP:
if (m == NULL || m->m_len < sizeof(struct lgrplctl))
error = EINVAL;
else
error = del_lgrp(mtod(m, struct lgrplctl *));
break;
case DVMRP_ADD_MRT:
if (m == NULL || m->m_len < sizeof(struct mrtctl))
error = EINVAL;
else
error = add_mrt(mtod(m, struct mrtctl *));
break;
case DVMRP_DEL_MRT:
if (m == NULL || m->m_len < sizeof(struct in_addr))
error = EINVAL;
else
error = del_mrt(mtod(m, struct in_addr *));
break;
default:
error = EOPNOTSUPP;
break;
}
return (error);
}
/*
* Enable multicast routing
*/
static int
ip_mrouter_init(so)
register struct socket *so;
{
if (so->so_type != SOCK_RAW ||
so->so_proto->pr_protocol != IPPROTO_IGMP)
return (EOPNOTSUPP);
if (ip_mrouter != NULL)
return (EADDRINUSE);
ip_mrouter = so;
return (0);
}
/*
* Disable multicast routing
*/
int
ip_mrouter_done()
{
register vifi_t vifi;
register int i;
register struct ifnet *ifp;
register int s;
struct ifreq ifr;
s = splnet();
/*
* For each phyint in use, free its local group list and
* disable promiscuous reception of all IP multicasts.
*/
for (vifi = 0; vifi < numvifs; vifi++) {
if (viftable[vifi].v_lcl_addr.s_addr != 0 &&
!(viftable[vifi].v_flags & VIFF_TUNNEL)) {
if (viftable[vifi].v_lcl_grps)
free(viftable[vifi].v_lcl_grps, M_MRTABLE);
satosin(&ifr.ifr_addr)->sin_family = AF_INET;
satosin(&ifr.ifr_addr)->sin_addr.s_addr = INADDR_ANY;
ifp = viftable[vifi].v_ifp;
(*ifp->if_ioctl)(ifp, SIOCDELMULTI, (caddr_t)&ifr);
}
}
bzero((caddr_t)viftable, sizeof(viftable));
numvifs = 0;
/*
* Free any multicast route entries.
*/
for (i = 0; i < MRTHASHSIZ; i++)
if (mrttable[i])
free(mrttable[i], M_MRTABLE);
bzero((caddr_t)mrttable, sizeof(mrttable));
cached_mrt = NULL;
ip_mrouter = NULL;
splx(s);
return (0);
}
/*
* Add a vif to the vif table
*/
static int
add_vif(vifcp)
register struct vifctl *vifcp;
{
register struct vif *vifp = viftable + vifcp->vifc_vifi;
register struct ifaddr *ifa;
register struct ifnet *ifp;
struct ifreq ifr;
register int error, s;
static struct sockaddr_in sin = { sizeof(sin), AF_INET };
if (vifcp->vifc_vifi >= MAXVIFS)
return (EINVAL);
if (vifp->v_lcl_addr.s_addr != 0)
return (EADDRINUSE);
/* Find the interface with an address in AF_INET family */
sin.sin_addr = vifcp->vifc_lcl_addr;
ifa = ifa_ifwithaddr((struct sockaddr *)&sin);
if (ifa == 0)
return (EADDRNOTAVAIL);
s = splnet();
if (vifcp->vifc_flags & VIFF_TUNNEL)
vifp->v_rmt_addr = vifcp->vifc_rmt_addr;
else {
/* Make sure the interface supports multicast */
ifp = ifa->ifa_ifp;
if ((ifp->if_flags & IFF_MULTICAST) == 0) {
splx(s);
return (EOPNOTSUPP);
}
/*
* Enable promiscuous reception of all IP multicasts
* from the interface.
*/
satosin(&ifr.ifr_addr)->sin_family = AF_INET;
satosin(&ifr.ifr_addr)->sin_addr.s_addr = INADDR_ANY;
error = (*ifp->if_ioctl)(ifp, SIOCADDMULTI, (caddr_t)&ifr);
if (error) {
splx(s);
return (error);
}
}
vifp->v_flags = vifcp->vifc_flags;
vifp->v_threshold = vifcp->vifc_threshold;
vifp->v_lcl_addr = vifcp->vifc_lcl_addr;
vifp->v_ifp = ifa->ifa_ifp;
/* Adjust numvifs up if the vifi is higher than numvifs */
if (numvifs <= vifcp->vifc_vifi)
numvifs = vifcp->vifc_vifi + 1;
splx(s);
return (0);
}
/*
* Delete a vif from the vif table
*/
static int
del_vif(vifip)
register vifi_t *vifip;
{
register struct vif *vifp = viftable + *vifip;
register struct ifnet *ifp;
register int i, s;
struct ifreq ifr;
if (*vifip >= numvifs)
return (EINVAL);
if (vifp->v_lcl_addr.s_addr == 0)
return (EADDRNOTAVAIL);
s = splnet();
if (!(vifp->v_flags & VIFF_TUNNEL)) {
if (vifp->v_lcl_grps)
free(vifp->v_lcl_grps, M_MRTABLE);
satosin(&ifr.ifr_addr)->sin_family = AF_INET;
satosin(&ifr.ifr_addr)->sin_addr.s_addr = INADDR_ANY;
ifp = vifp->v_ifp;
(*ifp->if_ioctl)(ifp, SIOCDELMULTI, (caddr_t)&ifr);
}
bzero((caddr_t)vifp, sizeof (*vifp));
/* Adjust numvifs down */
for (i = numvifs - 1; i >= 0; i--)
if (viftable[i].v_lcl_addr.s_addr != 0)
break;
numvifs = i + 1;
splx(s);
return (0);
}
/*
* Add the multicast group in the lgrpctl to the list of local multicast
* group memberships associated with the vif indexed by gcp->lgc_vifi.
*/
static int
add_lgrp(gcp)
register struct lgrplctl *gcp;
{
register struct vif *vifp;
register int s;
if (gcp->lgc_vifi >= numvifs)
return (EINVAL);
vifp = viftable + gcp->lgc_vifi;
if (vifp->v_lcl_addr.s_addr == 0 || (vifp->v_flags & VIFF_TUNNEL))
return (EADDRNOTAVAIL);
/* If not enough space in existing list, allocate a larger one */
s = splnet();
if (vifp->v_lcl_grps_n + 1 >= vifp->v_lcl_grps_max) {
register int num;
register struct in_addr *ip;
num = vifp->v_lcl_grps_max;
if (num <= 0)
num = 32; /* initial number */
else
num += num; /* double last number */
ip = (struct in_addr *)malloc(num * sizeof(*ip),
M_MRTABLE, M_NOWAIT);
if (ip == NULL) {
splx(s);
return (ENOBUFS);
}
bzero((caddr_t)ip, num * sizeof(*ip)); /* XXX paranoid */
bcopy((caddr_t)vifp->v_lcl_grps, (caddr_t)ip,
vifp->v_lcl_grps_n * sizeof(*ip));
vifp->v_lcl_grps_max = num;
if (vifp->v_lcl_grps)
free(vifp->v_lcl_grps, M_MRTABLE);
vifp->v_lcl_grps = ip;
splx(s);
}
vifp->v_lcl_grps[vifp->v_lcl_grps_n++] = gcp->lgc_gaddr;
if (gcp->lgc_gaddr.s_addr == vifp->v_cached_group)
vifp->v_cached_result = 1;
splx(s);
return (0);
}
/*
* Delete the the local multicast group associated with the vif
* indexed by gcp->lgc_vifi.
*/
static int
del_lgrp(gcp)
register struct lgrplctl *gcp;
{
register struct vif *vifp;
register int i, error, s;
if (gcp->lgc_vifi >= numvifs)
return (EINVAL);
vifp = viftable + gcp->lgc_vifi;
if (vifp->v_lcl_addr.s_addr == 0 || (vifp->v_flags & VIFF_TUNNEL))
return (EADDRNOTAVAIL);
s = splnet();
if (gcp->lgc_gaddr.s_addr == vifp->v_cached_group)
vifp->v_cached_result = 0;
error = EADDRNOTAVAIL;
for (i = 0; i < vifp->v_lcl_grps_n; ++i)
if (same(&gcp->lgc_gaddr, &vifp->v_lcl_grps[i])) {
error = 0;
vifp->v_lcl_grps_n--;
bcopy((caddr_t)&vifp->v_lcl_grps[i + 1],
(caddr_t)&vifp->v_lcl_grps[i],
(vifp->v_lcl_grps_n - i) * sizeof(struct in_addr));
error = 0;
break;
}
splx(s);
return (error);
}
/*
* Return 1 if gaddr is a member of the local group list for vifp.
*/
static int
grplst_member(vifp, gaddr)
register struct vif *vifp;
struct in_addr gaddr;
{
register int i, s;
register u_long addr;
mrtstat.mrts_grp_lookups++;
addr = gaddr.s_addr;
if (addr == vifp->v_cached_group)
return (vifp->v_cached_result);
mrtstat.mrts_grp_misses++;
for (i = 0; i < vifp->v_lcl_grps_n; ++i)
if (addr == vifp->v_lcl_grps[i].s_addr) {
s = splnet();
vifp->v_cached_group = addr;
vifp->v_cached_result = 1;
splx(s);
return (1);
}
s = splnet();
vifp->v_cached_group = addr;
vifp->v_cached_result = 0;
splx(s);
return (0);
}
/*
* A simple hash function: returns MRTHASHMOD of the low-order octet of
* the argument's network or subnet number.
*/
static u_long
nethash(in)
struct in_addr in;
{
register u_long n;
n = in_netof(in);
while ((n & 0xff) == 0)
n >>= 8;
return (MRTHASHMOD(n));
}
/*
* Add an mrt entry
*/
static int
add_mrt(mrtcp)
register struct mrtctl *mrtcp;
{
struct mrt *rt;
u_long hash;
int s;
if (rt = mrtfind(mrtcp->mrtc_origin)) {
/* Just update the route */
s = splnet();
rt->mrt_parent = mrtcp->mrtc_parent;
VIFM_COPY(mrtcp->mrtc_children, rt->mrt_children);
VIFM_COPY(mrtcp->mrtc_leaves, rt->mrt_leaves);
splx(s);
return (0);
}
s = splnet();
rt = (struct mrt *)malloc(sizeof(*rt), M_MRTABLE, M_NOWAIT);
if (rt == NULL) {
splx(s);
return (ENOBUFS);
}
/*
* insert new entry at head of hash chain
*/
rt->mrt_origin = mrtcp->mrtc_origin;
rt->mrt_originmask = mrtcp->mrtc_originmask;
rt->mrt_parent = mrtcp->mrtc_parent;
VIFM_COPY(mrtcp->mrtc_children, rt->mrt_children);
VIFM_COPY(mrtcp->mrtc_leaves, rt->mrt_leaves);
/* link into table */
hash = nethash(mrtcp->mrtc_origin);
rt->mrt_next = mrttable[hash];
mrttable[hash] = rt;
splx(s);
return (0);
}
/*
* Delete an mrt entry
*/
static int
del_mrt(origin)
register struct in_addr *origin;
{
register struct mrt *rt, *prev_rt;
register u_long hash = nethash(*origin);
register int s;
for (prev_rt = rt = mrttable[hash]; rt; prev_rt = rt, rt = rt->mrt_next)
if (origin->s_addr == rt->mrt_origin.s_addr)
break;
if (!rt)
return (ESRCH);
s = splnet();
if (rt == cached_mrt)
cached_mrt = NULL;
if (prev_rt == rt)
mrttable[hash] = rt->mrt_next;
else
prev_rt->mrt_next = rt->mrt_next;
free(rt, M_MRTABLE);
splx(s);
return (0);
}
/*
* Find a route for a given origin IP address.
*/
static struct mrt *
mrtfind(origin)
struct in_addr origin;
{
register struct mrt *rt;
register u_int hash;
register int s;
mrtstat.mrts_mrt_lookups++;
if (cached_mrt != NULL &&
(origin.s_addr & cached_originmask) == cached_origin)
return (cached_mrt);
mrtstat.mrts_mrt_misses++;
hash = nethash(origin);
for (rt = mrttable[hash]; rt; rt = rt->mrt_next)
if ((origin.s_addr & rt->mrt_originmask.s_addr) ==
rt->mrt_origin.s_addr) {
s = splnet();
cached_mrt = rt;
cached_origin = rt->mrt_origin.s_addr;
cached_originmask = rt->mrt_originmask.s_addr;
splx(s);
return (rt);
}
return (NULL);
}
/*
* IP multicast forwarding function. This function assumes that the packet
* pointed to by "ip" has arrived on (or is about to be sent to) the interface
* pointed to by "ifp", and the packet is to be relayed to other networks
* that have members of the packet's destination IP multicast group.
*
* The packet is returned unscathed to the caller, unless it is tunneled
* or erroneous, in which case a non-zero return value tells the caller to
* discard it.
*/
#define IP_HDR_LEN 20 /* # bytes of fixed IP header (excluding options) */
#define TUNNEL_LEN 12 /* # bytes of IP option for tunnel encapsulation */
int
ip_mforward(m, ifp)
register struct mbuf *m;
register struct ifnet *ifp;
{
register struct ip *ip = mtod(m, struct ip *);
register struct mrt *rt;
register struct vif *vifp;
register int vifi;
register u_char *ipoptions;
u_long tunnel_src;
if (ip->ip_hl < (IP_HDR_LEN + TUNNEL_LEN) >> 2 ||
(ipoptions = (u_char *)(ip + 1))[1] != IPOPT_LSRR ) {
/*
* Packet arrived via a physical interface.
*/
tunnel_src = 0;
} else {
/*
* Packet arrived through a tunnel.
*
* A tunneled packet has a single NOP option and a
* two-element loose-source-and-record-route (LSRR)
* option immediately following the fixed-size part of
* the IP header. At this point in processing, the IP
* header should contain the following IP addresses:
*
* original source - in the source address field
* destination group - in the destination address field
* remote tunnel end-point - in the first element of LSRR
* one of this host's addrs - in the second element of LSRR
*
* NOTE: RFC-1075 would have the original source and
* remote tunnel end-point addresses swapped. However,
* that could cause delivery of ICMP error messages to
* innocent applications on intermediate routing
* hosts! Therefore, we hereby change the spec.
*/
/*
* Verify that the tunnel options are well-formed.
*/
if (ipoptions[0] != IPOPT_NOP ||
ipoptions[2] != 11 || /* LSRR option length */
ipoptions[3] != 12 || /* LSRR address pointer */
(tunnel_src = *(u_long *)(&ipoptions[4])) == 0) {
mrtstat.mrts_bad_tunnel++;
return (1);
}
/*
* Delete the tunnel options from the packet.
*/
ovbcopy((caddr_t)(ipoptions + TUNNEL_LEN), (caddr_t)ipoptions,
(unsigned)(m->m_len - (IP_HDR_LEN + TUNNEL_LEN)));
m->m_len -= TUNNEL_LEN;
ip->ip_len -= TUNNEL_LEN;
ip->ip_hl -= TUNNEL_LEN >> 2;
}
/*
* Don't forward a packet with time-to-live of zero or one,
* or a packet destined to a local-only group.
*/
if (ip->ip_ttl <= 1 ||
ntohl(ip->ip_dst.s_addr) <= INADDR_MAX_LOCAL_GROUP)
return ((int)tunnel_src);
/*
* Don't forward if we don't have a route for the packet's origin.
*/
if (!(rt = mrtfind(ip->ip_src))) {
mrtstat.mrts_no_route++;
return ((int)tunnel_src);
}
/*
* Don't forward if it didn't arrive from the parent vif for its origin.
*/
vifi = rt->mrt_parent;
if (tunnel_src == 0 ) {
if ((viftable[vifi].v_flags & VIFF_TUNNEL) ||
viftable[vifi].v_ifp != ifp )
return ((int)tunnel_src);
} else {
if (!(viftable[vifi].v_flags & VIFF_TUNNEL) ||
viftable[vifi].v_rmt_addr.s_addr != tunnel_src )
return ((int)tunnel_src);
}
/*
* For each vif, decide if a copy of the packet should be forwarded.
* Forward if:
* - the ttl exceeds the vif's threshold AND
* - the vif is a child in the origin's route AND
* - ( the vif is not a leaf in the origin's route OR
* the destination group has members on the vif )
*
* (This might be speeded up with some sort of cache -- someday.)
*/
for (vifp = viftable, vifi = 0; vifi < numvifs; vifp++, vifi++) {
if (ip->ip_ttl > vifp->v_threshold &&
VIFM_ISSET(vifi, rt->mrt_children) &&
(!VIFM_ISSET(vifi, rt->mrt_leaves) ||
grplst_member(vifp, ip->ip_dst))) {
if (vifp->v_flags & VIFF_TUNNEL)
tunnel_send(m, vifp);
else
phyint_send(m, vifp);
}
}
return ((int)tunnel_src);
}
static void
phyint_send(m, vifp)
register struct mbuf *m;
register struct vif *vifp;
{
register struct ip *ip = mtod(m, struct ip *);
register struct mbuf *mb_copy;
register struct ip_moptions *imo;
register int error;
struct ip_moptions simo;
mb_copy = m_copy(m, 0, M_COPYALL);
if (mb_copy == NULL)
return;
imo = &simo;
imo->imo_multicast_ifp = vifp->v_ifp;
imo->imo_multicast_ttl = ip->ip_ttl - 1;
imo->imo_multicast_loop = 1;
error = ip_output(mb_copy, NULL, NULL, IP_FORWARDING, imo);
}
static void
tunnel_send(m, vifp)
register struct mbuf *m;
register struct vif *vifp;
{
register struct ip *ip = mtod(m, struct ip *);
register struct mbuf *mb_copy, *mb_opts;
register struct ip *ip_copy;
register int error;
register u_char *cp;
/*
* Make sure that adding the tunnel options won't exceed the
* maximum allowed number of option bytes.
*/
if (ip->ip_hl > (60 - TUNNEL_LEN) >> 2) {
mrtstat.mrts_cant_tunnel++;
return;
}
/*
* Get a private copy of the IP header so that changes to some
* of the IP fields don't damage the original header, which is
* examined later in ip_input.c.
*/
mb_copy = m_copy(m, IP_HDR_LEN, M_COPYALL);
if (mb_copy == NULL)
return;
MGETHDR(mb_opts, M_DONTWAIT, MT_HEADER);
if (mb_opts == NULL) {
m_freem(mb_copy);
return;
}
/*
* Make mb_opts be the new head of the packet chain.
* Any options of the packet were left in the old packet chain head
*/
mb_opts->m_next = mb_copy;
mb_opts->m_len = IP_HDR_LEN + TUNNEL_LEN;
mb_opts->m_data += MSIZE - mb_opts->m_len;
ip_copy = mtod(mb_opts, struct ip *);
/*
* Copy the base ip header to the new head mbuf.
*/
*ip_copy = *ip;
ip_copy->ip_ttl--;
ip_copy->ip_dst = vifp->v_rmt_addr; /* remote tunnel end-point */
/*
* Adjust the ip header length to account for the tunnel options.
*/
ip_copy->ip_hl += TUNNEL_LEN >> 2;
ip_copy->ip_len += TUNNEL_LEN;
/*
* Add the NOP and LSRR after the base ip header
*/
cp = (u_char *)(ip_copy + 1);
*cp++ = IPOPT_NOP;
*cp++ = IPOPT_LSRR;
*cp++ = 11; /* LSRR option length */
*cp++ = 8; /* LSSR pointer to second element */
*(u_long*)cp = vifp->v_lcl_addr.s_addr; /* local tunnel end-point */
cp += 4;
*(u_long*)cp = ip->ip_dst.s_addr; /* destination group */
error = ip_output(mb_opts, NULL, NULL, IP_FORWARDING, NULL);
}
#endif