FreeBSD/Linux Kernel Cross Reference
sys/netinet6/in6_rmx.c

     /*-
      * 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.
     *
     *      $KAME: in6_rmx.c,v 1.11 2001/07/26 06:53:16 jinmei Exp $
     */
    
    /*-
     * 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/cdefs.h>
    __FBSDID("$FreeBSD: releng/7.3/sys/netinet6/in6_rmx.c 189898 2009-03-16 18:15:52Z rwatson $");
    
    #include <sys/param.h>
    #include <sys/systm.h>
    #include <sys/kernel.h>
    #include <sys/sysctl.h>
    #include <sys/queue.h>
    #include <sys/socket.h>
    #include <sys/socketvar.h>
    #include <sys/mbuf.h>
    #include <sys/syslog.h>
    #include <sys/callout.h>
    
    #include <net/if.h>
    #include <net/route.h>
    #include <netinet/in.h>
    #include <netinet/ip_var.h>
    #include <netinet/in_var.h>
    
    #include <netinet/ip6.h>
    #include <netinet6/ip6_var.h>
    
    #include <netinet/icmp6.h>
    #include <netinet6/nd6.h>
   
   #include <netinet/tcp.h>
   #include <netinet/tcp_seq.h>
   #include <netinet/tcp_timer.h>
   #include <netinet/tcp_var.h>
   
   extern int      in6_inithead(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;
   
           if (IN6_IS_ADDR_MULTICAST(&sin6->sin6_addr))
                   rt->rt_flags |= RTF_MULTICAST;
   
           /*
            * 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 (!rt->rt_rmx.rmx_mtu && rt->rt_ifp)
                   rt->rt_rmx.rmx_mtu = IN6_LINKMTU(rt->rt_ifp);
   
           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_RNH_LOCKED|RTF_CLONING);
                   if (rt2) {
                           if (rt2->rt_flags & RTF_LLINFO &&
                                   rt2->rt_flags & RTF_HOST &&
                                   rt2->rt_gateway &&
                                   rt2->rt_gateway->sa_family == AF_LINK) {
                                   rtexpunge(rt2);
                                   RTFREE_LOCKED(rt2);
                                   ret = rn_addroute(v_arg, n_arg, head,
                                           treenodes);
                           } else
                                   RTFREE_LOCKED(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_RNH_LOCKED|RTF_CLONING);
                   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_LOCKED(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)
   {
           struct radix_node *rn = rn_match(v_arg, head);
           struct rtentry *rt = (struct rtentry *)rn;
   
           if (rt && rt->rt_refcnt == 0) { /* this is first reference */
                   if (rt->rt_flags & RTPRF_OURS) {
                           rt->rt_flags &= ~RTPRF_OURS;
                           rt->rt_rmx.rmx_expire = 0;
                   }
           }
           return rn;
   }
   
   SYSCTL_DECL(_net_inet6_ip6);
   
   static int rtq_reallyold = 60*60;
           /* one hour is ``really old'' */
   SYSCTL_INT(_net_inet6_ip6, IPV6CTL_RTEXPIRE, rtexpire,
           CTLFLAG_RW, &rtq_reallyold , 0, "");
   
   static int rtq_minreallyold = 10;
           /* never automatically crank down to less */
   SYSCTL_INT(_net_inet6_ip6, IPV6CTL_RTMINEXPIRE, rtminexpire,
           CTLFLAG_RW, &rtq_minreallyold , 0, "");
   
   static int rtq_toomany = 128;
           /* 128 cached routes is ``too many'' */
   SYSCTL_INT(_net_inet6_ip6, IPV6CTL_RTMAXCACHE, rtmaxcache,
           CTLFLAG_RW, &rtq_toomany , 0, "");
   
   
   /*
    * On last reference drop, mark the route as belong to us so that it can be
    * timed out.
    */
   static void
   in6_clsroute(struct radix_node *rn, struct radix_node_head *head)
   {
           struct rtentry *rt = (struct rtentry *)rn;
   
           RT_LOCK_ASSERT(rt);
   
           if (!(rt->rt_flags & RTF_UP))
                   return;         /* prophylactic measures */
   
           if ((rt->rt_flags & (RTF_LLINFO | RTF_HOST)) != RTF_HOST)
                   return;
   
           if ((rt->rt_flags & (RTF_WASCLONED | RTPRF_OURS)) != RTF_WASCLONED)
                   return;
   
           /*
            * As requested by David Greenman:
            * If rtq_reallyold is 0, just delete the route without
            * waiting for a timeout cycle to kill it.
            */
           if (rtq_reallyold != 0) {
                   rt->rt_flags |= RTPRF_OURS;
                   rt->rt_rmx.rmx_expire = time_uptime + rtq_reallyold;
           } else {
                   rtexpunge(rt);
           }
   }
   
   struct rtqk_arg {
           struct radix_node_head *rnh;
           int mode;
           int updating;
           int draining;
           int killed;
           int found;
           time_t nextstop;
   };
   
   /*
    * Get rid of old routes.  When draining, this deletes everything, even when
    * the timeout is not expired yet.  When updating, this makes sure that
    * nothing has a timeout longer than the current value of rtq_reallyold.
    */
   static int
   in6_rtqkill(struct radix_node *rn, void *rock)
   {
           struct rtqk_arg *ap = rock;
           struct rtentry *rt = (struct rtentry *)rn;
           int err;
   
           RADIX_NODE_HEAD_LOCK_ASSERT(ap->rnh);
   
           if (rt->rt_flags & RTPRF_OURS) {
                   ap->found++;
   
                   if (ap->draining || rt->rt_rmx.rmx_expire <= time_uptime) {
                           if (rt->rt_refcnt > 0)
                                   panic("rtqkill route really not free");
   
                           err = rtrequest(RTM_DELETE,
                                           (struct sockaddr *)rt_key(rt),
                                           rt->rt_gateway, rt_mask(rt),
                                           rt->rt_flags|RTF_RNH_LOCKED, 0);
                           if (err) {
                                   log(LOG_WARNING, "in6_rtqkill: error %d", err);
                           } else {
                                   ap->killed++;
                           }
                   } else {
                           if (ap->updating
                              && (rt->rt_rmx.rmx_expire - time_uptime
                                  > rtq_reallyold)) {
                                   rt->rt_rmx.rmx_expire = time_uptime
                                           + rtq_reallyold;
                           }
                           ap->nextstop = lmin(ap->nextstop,
                                               rt->rt_rmx.rmx_expire);
                   }
           }
   
           return 0;
   }
   
   #define RTQ_TIMEOUT     60*10   /* run no less than once every ten minutes */
   static int rtq_timeout = RTQ_TIMEOUT;
   static struct callout rtq_timer;
   
   static void
   in6_rtqtimo(void *rock)
   {
           struct radix_node_head *rnh = rock;
           struct rtqk_arg arg;
           struct timeval atv;
           static time_t last_adjusted_timeout = 0;
   
           arg.found = arg.killed = 0;
           arg.rnh = rnh;
           arg.nextstop = time_uptime + rtq_timeout;
           arg.draining = arg.updating = 0;
           RADIX_NODE_HEAD_LOCK(rnh);
           rnh->rnh_walktree(rnh, in6_rtqkill, &arg);
           RADIX_NODE_HEAD_UNLOCK(rnh);
   
           /*
            * Attempt to be somewhat dynamic about this:
            * If there are ``too many'' routes sitting around taking up space,
            * then crank down the timeout, and see if we can't make some more
            * go away.  However, we make sure that we will never adjust more
            * than once in rtq_timeout seconds, to keep from cranking down too
            * hard.
            */
           if ((arg.found - arg.killed > rtq_toomany)
              && (time_uptime - last_adjusted_timeout >= rtq_timeout)
              && rtq_reallyold > rtq_minreallyold) {
                   rtq_reallyold = 2*rtq_reallyold / 3;
                   if (rtq_reallyold < rtq_minreallyold) {
                           rtq_reallyold = rtq_minreallyold;
                   }
   
                   last_adjusted_timeout = time_uptime;
   #ifdef DIAGNOSTIC
                   log(LOG_DEBUG, "in6_rtqtimo: adjusted rtq_reallyold to %d",
                       rtq_reallyold);
   #endif
                   arg.found = arg.killed = 0;
                   arg.updating = 1;
                   RADIX_NODE_HEAD_LOCK(rnh);
                   rnh->rnh_walktree(rnh, in6_rtqkill, &arg);
                   RADIX_NODE_HEAD_UNLOCK(rnh);
           }
   
           atv.tv_usec = 0;
           atv.tv_sec = arg.nextstop - time_uptime;
           callout_reset(&rtq_timer, tvtohz(&atv), in6_rtqtimo, rock);
   }
   
   /*
    * Age old PMTUs.
    */
   struct mtuex_arg {
           struct radix_node_head *rnh;
           time_t nextstop;
   };
   static struct callout rtq_mtutimer;
   
   static int
   in6_mtuexpire(struct radix_node *rn, void *rock)
   {
           struct rtentry *rt = (struct rtentry *)rn;
           struct mtuex_arg *ap = rock;
   
           /* sanity */
           if (!rt)
                   panic("rt == NULL in in6_mtuexpire");
   
           if (rt->rt_rmx.rmx_expire && !(rt->rt_flags & RTF_PROBEMTU)) {
                   if (rt->rt_rmx.rmx_expire <= time_uptime) {
                           rt->rt_flags |= RTF_PROBEMTU;
                   } else {
                           ap->nextstop = lmin(ap->nextstop,
                                           rt->rt_rmx.rmx_expire);
                   }
           }
   
           return 0;
   }
   
   #define MTUTIMO_DEFAULT (60*1)
   
   static void
   in6_mtutimo(void *rock)
   {
           struct radix_node_head *rnh = rock;
           struct mtuex_arg arg;
           struct timeval atv;
   
           arg.rnh = rnh;
           arg.nextstop = time_uptime + MTUTIMO_DEFAULT;
           RADIX_NODE_HEAD_LOCK(rnh);
           rnh->rnh_walktree(rnh, in6_mtuexpire, &arg);
           RADIX_NODE_HEAD_UNLOCK(rnh);
   
           atv.tv_usec = 0;
           atv.tv_sec = arg.nextstop - time_uptime;
           if (atv.tv_sec < 0) {
                   printf("invalid mtu expiration time on routing table\n");
                   arg.nextstop = time_uptime + 30;        /* last resort */
                   atv.tv_sec = 30;
           }
           callout_reset(&rtq_mtutimer, tvtohz(&atv), in6_mtutimo, rock);
   }
   
   #if 0
   void
   in6_rtqdrain(void)
   {
           struct radix_node_head *rnh = rt_tables[AF_INET6];
           struct rtqk_arg arg;
   
           arg.found = arg.killed = 0;
           arg.rnh = rnh;
           arg.nextstop = 0;
           arg.draining = 1;
           arg.updating = 0;
           RADIX_NODE_HEAD_LOCK(rnh);
           rnh->rnh_walktree(rnh, in6_rtqkill, &arg);
           RADIX_NODE_HEAD_UNLOCK(rnh);
   }
   #endif
   
   /*
    * Initialize our routing tree.
    * XXX MRT When off == 0, we are being called from vfs_export.c
    * so just set up their table and leave. (we know what the correct
    * value should be so just use that).. FIX AFTER RELENG_7 is MFC'd
    * see also comments in in_inithead() vfs_export.c and domain.h
    */
   int
   in6_inithead(void **head, int off)
   {
           struct radix_node_head *rnh;
   
           if (!rn_inithead(head, offsetof(struct sockaddr_in6, sin6_addr) << 3))
                   return 0;               /* See above */
   
           if (off == 0)           /* See above */
                   return 1;       /* only do the rest for the real thing */
   
           rnh = *head;
           rnh->rnh_addaddr = in6_addroute;
           rnh->rnh_matchaddr = in6_matroute;
           rnh->rnh_close = in6_clsroute;
           callout_init(&rtq_timer, CALLOUT_MPSAFE);
           in6_rtqtimo(rnh);       /* kick off timeout first time */
           callout_init(&rtq_mtutimer, CALLOUT_MPSAFE);
           in6_mtutimo(rnh);       /* kick off timeout first time */
           return 1;
   }

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