in6_rmx.c

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//==========================================================================
//
//      src/sys/netinet6/in6_rmx.c
//
//==========================================================================
//####BSDCOPYRIGHTBEGIN####
//
// -------------------------------------------
//
// Portions of this software may have been derived from OpenBSD, 
// FreeBSD or other sources, and are covered by the appropriate
// copyright disclaimers included herein.
//
// Portions created by Red Hat are
// Copyright (C) 2002 Red Hat, Inc. All Rights Reserved.
//
// -------------------------------------------
//
//####BSDCOPYRIGHTEND####
//==========================================================================

/*	$KAME: in6_rmx.c,v 1.11 2001/07/26 06:53:16 jinmei 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.
 */

/*
 * Copyright 1994, 1995 Massachusetts Institute of Technology
 *
 * Permission to use, copy, modify, and distribute this software and
 * its documentation for any purpose and without fee is hereby
 * granted, provided that both the above copyright notice and this
 * permission notice appear in all copies, that both the above
 * copyright notice and this permission notice appear in all
 * supporting documentation, and that the name of M.I.T. not be used
 * in advertising or publicity pertaining to distribution of the
 * software without specific, written prior permission.  M.I.T. makes
 * no representations about the suitability of this software for any
 * purpose.  It is provided "as is" without express or implied
 * warranty.
 *
 * THIS SOFTWARE IS PROVIDED BY M.I.T. ``AS IS''.  M.I.T. DISCLAIMS
 * ALL EXPRESS OR IMPLIED WARRANTIES WITH REGARD TO THIS SOFTWARE,
 * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. IN NO EVENT
 * SHALL M.I.T. 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.
 *
 */

/*
 * This code does two things necessary for the enhanced TCP metrics to
 * function in a useful manner:
 *  1) It marks all non-host routes as `cloning', thus ensuring that
 *     every actual reference to such a route actually gets turned
 *     into a reference to a host route to the specific destination
 *     requested.
 *  2) When such routes lose all their references, it arranges for them
 *     to be deleted in some random collection of circumstances, so that
 *     a large quantity of stale routing data is not kept in kernel memory
 *     indefinitely.  See in6_rtqtimo() below for the exact mechanism.
 */

#include <sys/param.h>
#include <sys/sysctl.h>
#include <sys/queue.h>
#include <sys/socket.h>
#include <sys/socketvar.h>
#include <sys/mbuf.h>

#include <net/if.h>
#include <net/route.h>
#include <netinet/in.h>
#if defined(__FreeBSD__) && __FreeBSD__ >= 3
#include <netinet/ip_var.h>
#endif
#include <netinet/in_var.h>

#include <netinet/ip6.h>
#include <netinet6/ip6_var.h>

#include <netinet/icmp6.h>

#if !(defined(__FreeBSD__) && __FreeBSD__ >= 3)
#include <netinet6/tcp6.h>
#include <netinet6/tcp6_seq.h>
#include <netinet6/tcp6_timer.h>
#include <netinet6/tcp6_var.h>
#else
#include <netinet/tcp.h>
#include <netinet/tcp_seq.h>
#include <netinet/tcp_timer.h>
#include <netinet/tcp_var.h>
#endif

#if !(defined(__FreeBSD__) && __FreeBSD__ >= 3)
#define tcp_sendspace tcp6_sendspace
#define tcp_recvspace tcp6_recvspace
#define time_second time.tv_sec
#define tvtohz hzto
#endif

extern int	in6_inithead __P((void **head, int off));

#define RTPRF_OURS		RTF_PROTO3	/* set on routes we manage */

/*
 * Do what we need to do when inserting a route.
 */
static struct radix_node *
in6_addroute(void *v_arg, void *n_arg, struct radix_node_head *head,
	    struct radix_node *treenodes)
{
	struct rtentry *rt = (struct rtentry *)treenodes;
	struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)rt_key(rt);
	struct radix_node *ret;

	/*
	 * For IPv6, all unicast non-host routes are automatically cloning.
	 */
	if (IN6_IS_ADDR_MULTICAST(&sin6->sin6_addr))
		rt->rt_flags |= RTF_MULTICAST;

	if (!(rt->rt_flags & (RTF_HOST | RTF_CLONING | RTF_MULTICAST))) {
		rt->rt_flags |= RTF_PRCLONING;
	}

	/*
	 * A little bit of help for both IPv6 output and input:
	 *   For local addresses, we make sure that RTF_LOCAL is set,
	 *   with the thought that this might one day be used to speed up
	 *   ip_input().
	 *
	 * We also mark routes to multicast addresses as such, because
	 * it's easy to do and might be useful (but this is much more
	 * dubious since it's so easy to inspect the address).  (This
	 * is done above.)
	 *
	 * XXX
	 * should elaborate the code.
	 */
	if (rt->rt_flags & RTF_HOST) {
		if (IN6_ARE_ADDR_EQUAL(&satosin6(rt->rt_ifa->ifa_addr)
					->sin6_addr,
				       &sin6->sin6_addr)) {
			rt->rt_flags |= RTF_LOCAL;
		}
	}

#if __FreeBSD__ <= 2
	/*
	 * We also specify a send and receive pipe size for every
	 * route added, to help TCP a bit.  TCP doesn't actually
	 * want a true pipe size, which would be prohibitive in memory
	 * costs and is hard to compute anyway; it simply uses these
	 * values to size its buffers.  So, we fill them in with the
	 * same values that TCP would have used anyway, and allow the
	 * installing program or the link layer to override these values
	 * as it sees fit.  This will hopefully allow TCP more
	 * opportunities to save its ssthresh value.
	 */
	if (!rt->rt_rmx.rmx_sendpipe && !(rt->rt_rmx.rmx_locks & RTV_SPIPE))
		rt->rt_rmx.rmx_sendpipe = tcp_sendspace;

	if (!rt->rt_rmx.rmx_recvpipe && !(rt->rt_rmx.rmx_locks & RTV_RPIPE))
		rt->rt_rmx.rmx_recvpipe = tcp_recvspace;
#endif

	if (!rt->rt_rmx.rmx_mtu && !(rt->rt_rmx.rmx_locks & RTV_MTU)
	    && rt->rt_ifp)
		rt->rt_rmx.rmx_mtu = rt->rt_ifp->if_mtu;

	ret = rn_addroute(v_arg, n_arg, head, treenodes);
	if (ret == NULL && rt->rt_flags & RTF_HOST) {
		struct rtentry *rt2;
		/*
		 * We are trying to add a host route, but can't.
		 * Find out if it is because of an
		 * ARP entry and delete it if so.
		 */
		rt2 = rtalloc1((struct sockaddr *)sin6, 0,
				RTF_CLONING | RTF_PRCLONING);
		if (rt2) {
			if (rt2->rt_flags & RTF_LLINFO &&
				rt2->rt_flags & RTF_HOST &&
				rt2->rt_gateway &&
				rt2->rt_gateway->sa_family == AF_LINK) {
				rtrequest(RTM_DELETE,
					  (struct sockaddr *)rt_key(rt2),
					  rt2->rt_gateway,
					  rt_mask(rt2), rt2->rt_flags, 0);
				ret = rn_addroute(v_arg, n_arg, head,
					treenodes);
			}
			RTFREE(rt2);
		}
	} else if (ret == NULL && rt->rt_flags & RTF_CLONING) {
		struct rtentry *rt2;
		/*
		 * We are trying to add a net route, but can't.
		 * The following case should be allowed, so we'll make a
		 * special check for this:
		 *	Two IPv6 addresses with the same prefix is assigned
		 *	to a single interrface.
		 *	# ifconfig if0 inet6 3ffe:0501::1 prefix 64 alias (*1)
		 *	# ifconfig if0 inet6 3ffe:0501::2 prefix 64 alias (*2)
		 *	In this case, (*1) and (*2) want to add the same
		 *	net route entry, 3ffe:0501:: -> if0.
		 *	This case should not raise an error.
		 */
		rt2 = rtalloc1((struct sockaddr *)sin6, 0,
				RTF_CLONING | RTF_PRCLONING);
		if (rt2) {
			if ((rt2->rt_flags & (RTF_CLONING|RTF_HOST|RTF_GATEWAY))
					== RTF_CLONING
			 && rt2->rt_gateway
			 && rt2->rt_gateway->sa_family == AF_LINK
			 && rt2->rt_ifp == rt->rt_ifp) {
				ret = rt2->rt_nodes;
			}
			RTFREE(rt2);
		}
	}
	return ret;
}

/*
 * This code is the inverse of in6_clsroute: on first reference, if we
 * were managing the route, stop doing so and set the expiration timer
 * back off again.
 */
static struct radix_node *
in6_matroute(void *v_arg, struct radix_node_head *head)
{