ip_mroute.c

早期freebsd实现

/*
 * 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	8.2 (Berkeley) 11/15/93
 */

/*
 * 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/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.
 */