The Design and Implementation of the FreeBSD Operating System, Second Edition
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FreeBSD/Linux Kernel Cross Reference
sys/netinet/in_rmx.c

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    1 /*-
    2  * Copyright 1994, 1995 Massachusetts Institute of Technology
    3  *
    4  * Permission to use, copy, modify, and distribute this software and
    5  * its documentation for any purpose and without fee is hereby
    6  * granted, provided that both the above copyright notice and this
    7  * permission notice appear in all copies, that both the above
    8  * copyright notice and this permission notice appear in all
    9  * supporting documentation, and that the name of M.I.T. not be used
   10  * in advertising or publicity pertaining to distribution of the
   11  * software without specific, written prior permission.  M.I.T. makes
   12  * no representations about the suitability of this software for any
   13  * purpose.  It is provided "as is" without express or implied
   14  * warranty.
   15  *
   16  * THIS SOFTWARE IS PROVIDED BY M.I.T. ``AS IS''.  M.I.T. DISCLAIMS
   17  * ALL EXPRESS OR IMPLIED WARRANTIES WITH REGARD TO THIS SOFTWARE,
   18  * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
   19  * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. IN NO EVENT
   20  * SHALL M.I.T. BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
   21  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
   22  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
   23  * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
   24  * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
   25  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
   26  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   27  * SUCH DAMAGE.
   28  */
   29 
   30 #include <sys/cdefs.h>
   31 __FBSDID("$FreeBSD: releng/10.1/sys/netinet/in_rmx.c 263478 2014-03-21 15:15:30Z glebius $");
   32 
   33 #include <sys/param.h>
   34 #include <sys/systm.h>
   35 #include <sys/kernel.h>
   36 #include <sys/sysctl.h>
   37 #include <sys/socket.h>
   38 #include <sys/mbuf.h>
   39 #include <sys/syslog.h>
   40 #include <sys/callout.h>
   41 
   42 #include <net/if.h>
   43 #include <net/route.h>
   44 #include <net/vnet.h>
   45 
   46 #include <netinet/in.h>
   47 #include <netinet/in_var.h>
   48 #include <netinet/ip.h>
   49 #include <netinet/ip_icmp.h>
   50 #include <netinet/ip_var.h>
   51 
   52 extern int      in_inithead(void **head, int off);
   53 #ifdef VIMAGE
   54 extern int      in_detachhead(void **head, int off);
   55 #endif
   56 
   57 #define RTPRF_OURS              RTF_PROTO3      /* set on routes we manage */
   58 
   59 /*
   60  * Do what we need to do when inserting a route.
   61  */
   62 static struct radix_node *
   63 in_addroute(void *v_arg, void *n_arg, struct radix_node_head *head,
   64     struct radix_node *treenodes)
   65 {
   66         struct rtentry *rt = (struct rtentry *)treenodes;
   67         struct sockaddr_in *sin = (struct sockaddr_in *)rt_key(rt);
   68 
   69         RADIX_NODE_HEAD_WLOCK_ASSERT(head);
   70         /*
   71          * A little bit of help for both IP output and input:
   72          *   For host routes, we make sure that RTF_BROADCAST
   73          *   is set for anything that looks like a broadcast address.
   74          *   This way, we can avoid an expensive call to in_broadcast()
   75          *   in ip_output() most of the time (because the route passed
   76          *   to ip_output() is almost always a host route).
   77          *
   78          *   We also do the same for local addresses, with the thought
   79          *   that this might one day be used to speed up ip_input().
   80          *
   81          * We also mark routes to multicast addresses as such, because
   82          * it's easy to do and might be useful (but this is much more
   83          * dubious since it's so easy to inspect the address).
   84          */
   85         if (rt->rt_flags & RTF_HOST) {
   86                 if (in_broadcast(sin->sin_addr, rt->rt_ifp)) {
   87                         rt->rt_flags |= RTF_BROADCAST;
   88                 } else if (satosin(rt->rt_ifa->ifa_addr)->sin_addr.s_addr ==
   89                     sin->sin_addr.s_addr) {
   90                         rt->rt_flags |= RTF_LOCAL;
   91                 }
   92         }
   93         if (IN_MULTICAST(ntohl(sin->sin_addr.s_addr)))
   94                 rt->rt_flags |= RTF_MULTICAST;
   95 
   96         if (rt->rt_mtu == 0 && rt->rt_ifp != NULL)
   97                 rt->rt_mtu = rt->rt_ifp->if_mtu;
   98 
   99         return (rn_addroute(v_arg, n_arg, head, treenodes));
  100 }
  101 
  102 /*
  103  * This code is the inverse of in_clsroute: on first reference, if we
  104  * were managing the route, stop doing so and set the expiration timer
  105  * back off again.
  106  */
  107 static struct radix_node *
  108 in_matroute(void *v_arg, struct radix_node_head *head)
  109 {
  110         struct radix_node *rn = rn_match(v_arg, head);
  111         struct rtentry *rt = (struct rtentry *)rn;
  112 
  113         if (rt) {
  114                 RT_LOCK(rt);
  115                 if (rt->rt_flags & RTPRF_OURS) {
  116                         rt->rt_flags &= ~RTPRF_OURS;
  117                         rt->rt_expire = 0;
  118                 }
  119                 RT_UNLOCK(rt);
  120         }
  121         return rn;
  122 }
  123 
  124 static VNET_DEFINE(int, rtq_reallyold) = 60*60; /* one hour is "really old" */
  125 #define V_rtq_reallyold         VNET(rtq_reallyold)
  126 SYSCTL_VNET_INT(_net_inet_ip, IPCTL_RTEXPIRE, rtexpire, CTLFLAG_RW,
  127     &VNET_NAME(rtq_reallyold), 0,
  128     "Default expiration time on dynamically learned routes");
  129 
  130 /* never automatically crank down to less */
  131 static VNET_DEFINE(int, rtq_minreallyold) = 10;
  132 #define V_rtq_minreallyold      VNET(rtq_minreallyold)
  133 SYSCTL_VNET_INT(_net_inet_ip, IPCTL_RTMINEXPIRE, rtminexpire, CTLFLAG_RW,
  134     &VNET_NAME(rtq_minreallyold), 0,
  135     "Minimum time to attempt to hold onto dynamically learned routes");
  136 
  137 /* 128 cached routes is "too many" */
  138 static VNET_DEFINE(int, rtq_toomany) = 128;
  139 #define V_rtq_toomany           VNET(rtq_toomany)
  140 SYSCTL_VNET_INT(_net_inet_ip, IPCTL_RTMAXCACHE, rtmaxcache, CTLFLAG_RW,
  141     &VNET_NAME(rtq_toomany), 0,
  142     "Upper limit on dynamically learned routes");
  143 
  144 /*
  145  * On last reference drop, mark the route as belong to us so that it can be
  146  * timed out.
  147  */
  148 static void
  149 in_clsroute(struct radix_node *rn, struct radix_node_head *head)
  150 {
  151         struct rtentry *rt = (struct rtentry *)rn;
  152 
  153         RT_LOCK_ASSERT(rt);
  154 
  155         if (!(rt->rt_flags & RTF_UP))
  156                 return;                 /* prophylactic measures */
  157 
  158         if (rt->rt_flags & RTPRF_OURS)
  159                 return;
  160 
  161         if (!(rt->rt_flags & RTF_DYNAMIC))
  162                 return;
  163 
  164         /*
  165          * If rtq_reallyold is 0, just delete the route without
  166          * waiting for a timeout cycle to kill it.
  167          */
  168         if (V_rtq_reallyold != 0) {
  169                 rt->rt_flags |= RTPRF_OURS;
  170                 rt->rt_expire = time_uptime + V_rtq_reallyold;
  171         } else {
  172                 rtexpunge(rt);
  173         }
  174 }
  175 
  176 struct rtqk_arg {
  177         struct radix_node_head *rnh;
  178         int draining;
  179         int killed;
  180         int found;
  181         int updating;
  182         time_t nextstop;
  183 };
  184 
  185 /*
  186  * Get rid of old routes.  When draining, this deletes everything, even when
  187  * the timeout is not expired yet.  When updating, this makes sure that
  188  * nothing has a timeout longer than the current value of rtq_reallyold.
  189  */
  190 static int
  191 in_rtqkill(struct radix_node *rn, void *rock)
  192 {
  193         struct rtqk_arg *ap = rock;
  194         struct rtentry *rt = (struct rtentry *)rn;
  195         int err;
  196 
  197         RADIX_NODE_HEAD_WLOCK_ASSERT(ap->rnh);
  198 
  199         if (rt->rt_flags & RTPRF_OURS) {
  200                 ap->found++;
  201 
  202                 if (ap->draining || rt->rt_expire <= time_uptime) {
  203                         if (rt->rt_refcnt > 0)
  204                                 panic("rtqkill route really not free");
  205 
  206                         err = in_rtrequest(RTM_DELETE,
  207                                         (struct sockaddr *)rt_key(rt),
  208                                         rt->rt_gateway, rt_mask(rt),
  209                                         rt->rt_flags | RTF_RNH_LOCKED, 0,
  210                                         rt->rt_fibnum);
  211                         if (err) {
  212                                 log(LOG_WARNING, "in_rtqkill: error %d\n", err);
  213                         } else {
  214                                 ap->killed++;
  215                         }
  216                 } else {
  217                         if (ap->updating &&
  218                             (rt->rt_expire - time_uptime > V_rtq_reallyold))
  219                                 rt->rt_expire = time_uptime + V_rtq_reallyold;
  220                         ap->nextstop = lmin(ap->nextstop, rt->rt_expire);
  221                 }
  222         }
  223 
  224         return 0;
  225 }
  226 
  227 #define RTQ_TIMEOUT     60*10   /* run no less than once every ten minutes */
  228 static VNET_DEFINE(int, rtq_timeout) = RTQ_TIMEOUT;
  229 static VNET_DEFINE(struct callout, rtq_timer);
  230 
  231 #define V_rtq_timeout           VNET(rtq_timeout)
  232 #define V_rtq_timer             VNET(rtq_timer)
  233 
  234 static void in_rtqtimo_one(void *rock);
  235 
  236 static void
  237 in_rtqtimo(void *rock)
  238 {
  239         CURVNET_SET((struct vnet *) rock);
  240         int fibnum;
  241         void *newrock;
  242         struct timeval atv;
  243 
  244         for (fibnum = 0; fibnum < rt_numfibs; fibnum++) {
  245                 newrock = rt_tables_get_rnh(fibnum, AF_INET);
  246                 if (newrock != NULL)
  247                         in_rtqtimo_one(newrock);
  248         }
  249         atv.tv_usec = 0;
  250         atv.tv_sec = V_rtq_timeout;
  251         callout_reset(&V_rtq_timer, tvtohz(&atv), in_rtqtimo, rock);
  252         CURVNET_RESTORE();
  253 }
  254 
  255 static void
  256 in_rtqtimo_one(void *rock)
  257 {
  258         struct radix_node_head *rnh = rock;
  259         struct rtqk_arg arg;
  260         static time_t last_adjusted_timeout = 0;
  261 
  262         arg.found = arg.killed = 0;
  263         arg.rnh = rnh;
  264         arg.nextstop = time_uptime + V_rtq_timeout;
  265         arg.draining = arg.updating = 0;
  266         RADIX_NODE_HEAD_LOCK(rnh);
  267         rnh->rnh_walktree(rnh, in_rtqkill, &arg);
  268         RADIX_NODE_HEAD_UNLOCK(rnh);
  269 
  270         /*
  271          * Attempt to be somewhat dynamic about this:
  272          * If there are ``too many'' routes sitting around taking up space,
  273          * then crank down the timeout, and see if we can't make some more
  274          * go away.  However, we make sure that we will never adjust more
  275          * than once in rtq_timeout seconds, to keep from cranking down too
  276          * hard.
  277          */
  278         if ((arg.found - arg.killed > V_rtq_toomany) &&
  279             (time_uptime - last_adjusted_timeout >= V_rtq_timeout) &&
  280             V_rtq_reallyold > V_rtq_minreallyold) {
  281                 V_rtq_reallyold = 2 * V_rtq_reallyold / 3;
  282                 if (V_rtq_reallyold < V_rtq_minreallyold) {
  283                         V_rtq_reallyold = V_rtq_minreallyold;
  284                 }
  285 
  286                 last_adjusted_timeout = time_uptime;
  287 #ifdef DIAGNOSTIC
  288                 log(LOG_DEBUG, "in_rtqtimo: adjusted rtq_reallyold to %d\n",
  289                     V_rtq_reallyold);
  290 #endif
  291                 arg.found = arg.killed = 0;
  292                 arg.updating = 1;
  293                 RADIX_NODE_HEAD_LOCK(rnh);
  294                 rnh->rnh_walktree(rnh, in_rtqkill, &arg);
  295                 RADIX_NODE_HEAD_UNLOCK(rnh);
  296         }
  297 
  298 }
  299 
  300 void
  301 in_rtqdrain(void)
  302 {
  303         VNET_ITERATOR_DECL(vnet_iter);
  304         struct radix_node_head *rnh;
  305         struct rtqk_arg arg;
  306         int     fibnum;
  307 
  308         VNET_LIST_RLOCK_NOSLEEP();
  309         VNET_FOREACH(vnet_iter) {
  310                 CURVNET_SET(vnet_iter);
  311 
  312                 for ( fibnum = 0; fibnum < rt_numfibs; fibnum++) {
  313                         rnh = rt_tables_get_rnh(fibnum, AF_INET);
  314                         arg.found = arg.killed = 0;
  315                         arg.rnh = rnh;
  316                         arg.nextstop = 0;
  317                         arg.draining = 1;
  318                         arg.updating = 0;
  319                         RADIX_NODE_HEAD_LOCK(rnh);
  320                         rnh->rnh_walktree(rnh, in_rtqkill, &arg);
  321                         RADIX_NODE_HEAD_UNLOCK(rnh);
  322                 }
  323                 CURVNET_RESTORE();
  324         }
  325         VNET_LIST_RUNLOCK_NOSLEEP();
  326 }
  327 
  328 void
  329 in_setmatchfunc(struct radix_node_head *rnh, int val)
  330 {
  331 
  332         rnh->rnh_matchaddr = (val != 0) ? rn_match : in_matroute;
  333 }
  334 
  335 static int _in_rt_was_here;
  336 /*
  337  * Initialize our routing tree.
  338  */
  339 int
  340 in_inithead(void **head, int off)
  341 {
  342         struct radix_node_head *rnh;
  343 
  344         /* XXX MRT
  345          * This can be called from vfs_export.c too in which case 'off'
  346          * will be 0. We know the correct value so just use that and
  347          * return directly if it was 0.
  348          * This is a hack that replaces an even worse hack on a bad hack
  349          * on a bad design. After RELENG_7 this should be fixed but that
  350          * will change the ABI, so for now do it this way.
  351          */
  352         if (!rn_inithead(head, 32))
  353                 return 0;
  354 
  355         if (off == 0)           /* XXX MRT  see above */
  356                 return 1;       /* only do the rest for a real routing table */
  357 
  358         rnh = *head;
  359         rnh->rnh_addaddr = in_addroute;
  360         in_setmatchfunc(rnh, V_drop_redirect);
  361         rnh->rnh_close = in_clsroute;
  362         if (_in_rt_was_here == 0 ) {
  363                 callout_init(&V_rtq_timer, CALLOUT_MPSAFE);
  364                 callout_reset(&V_rtq_timer, 1, in_rtqtimo, curvnet);
  365                 _in_rt_was_here = 1;
  366         }
  367         return 1;
  368 }
  369 
  370 #ifdef VIMAGE
  371 int
  372 in_detachhead(void **head, int off)
  373 {
  374 
  375         callout_drain(&V_rtq_timer);
  376         return (1);
  377 }
  378 #endif
  379 
  380 /*
  381  * This zaps old routes when the interface goes down or interface
  382  * address is deleted.  In the latter case, it deletes static routes
  383  * that point to this address.  If we don't do this, we may end up
  384  * using the old address in the future.  The ones we always want to
  385  * get rid of are things like ARP entries, since the user might down
  386  * the interface, walk over to a completely different network, and
  387  * plug back in.
  388  */
  389 struct in_ifadown_arg {
  390         struct ifaddr *ifa;
  391         int del;
  392 };
  393 
  394 static int
  395 in_ifadownkill(struct radix_node *rn, void *xap)
  396 {
  397         struct in_ifadown_arg *ap = xap;
  398         struct rtentry *rt = (struct rtentry *)rn;
  399 
  400         RT_LOCK(rt);
  401         if (rt->rt_ifa == ap->ifa &&
  402             (ap->del || !(rt->rt_flags & RTF_STATIC))) {
  403                 /*
  404                  * Aquire a reference so that it can later be freed
  405                  * as the refcount would be 0 here in case of at least
  406                  * ap->del.
  407                  */
  408                 RT_ADDREF(rt);
  409                 /*
  410                  * Disconnect it from the tree and permit protocols
  411                  * to cleanup.
  412                  */
  413                 rtexpunge(rt);
  414                 /*
  415                  * At this point it is an rttrash node, and in case
  416                  * the above is the only reference we must free it.
  417                  * If we do not noone will have a pointer and the
  418                  * rtentry will be leaked forever.
  419                  * In case someone else holds a reference, we are
  420                  * fine as we only decrement the refcount. In that
  421                  * case if the other entity calls RT_REMREF, we
  422                  * will still be leaking but at least we tried.
  423                  */
  424                 RTFREE_LOCKED(rt);
  425                 return (0);
  426         }
  427         RT_UNLOCK(rt);
  428         return 0;
  429 }
  430 
  431 int
  432 in_ifadown(struct ifaddr *ifa, int delete)
  433 {
  434         struct in_ifadown_arg arg;
  435         struct radix_node_head *rnh;
  436         int     fibnum;
  437 
  438         if (ifa->ifa_addr->sa_family != AF_INET)
  439                 return 1;
  440 
  441         for ( fibnum = 0; fibnum < rt_numfibs; fibnum++) {
  442                 rnh = rt_tables_get_rnh(fibnum, AF_INET);
  443                 arg.ifa = ifa;
  444                 arg.del = delete;
  445                 RADIX_NODE_HEAD_LOCK(rnh);
  446                 rnh->rnh_walktree(rnh, in_ifadownkill, &arg);
  447                 RADIX_NODE_HEAD_UNLOCK(rnh);
  448                 ifa->ifa_flags &= ~IFA_ROUTE;           /* XXXlocking? */
  449         }
  450         return 0;
  451 }
  452 
  453 /*
  454  * inet versions of rt functions. These have fib extensions and 
  455  * for now will just reference the _fib variants.
  456  * eventually this order will be reversed,
  457  */
  458 void
  459 in_rtalloc_ign(struct route *ro, u_long ignflags, u_int fibnum)
  460 {
  461         rtalloc_ign_fib(ro, ignflags, fibnum);
  462 }
  463 
  464 int
  465 in_rtrequest( int req,
  466         struct sockaddr *dst,
  467         struct sockaddr *gateway,
  468         struct sockaddr *netmask,
  469         int flags,
  470         struct rtentry **ret_nrt,
  471         u_int fibnum)
  472 {
  473         return (rtrequest_fib(req, dst, gateway, netmask, 
  474             flags, ret_nrt, fibnum));
  475 }
  476 
  477 struct rtentry *
  478 in_rtalloc1(struct sockaddr *dst, int report, u_long ignflags, u_int fibnum)
  479 {
  480         return (rtalloc1_fib(dst, report, ignflags, fibnum));
  481 }
  482 
  483 void
  484 in_rtredirect(struct sockaddr *dst,
  485         struct sockaddr *gateway,
  486         struct sockaddr *netmask,
  487         int flags,
  488         struct sockaddr *src,
  489         u_int fibnum)
  490 {
  491         rtredirect_fib(dst, gateway, netmask, flags, src, fibnum);
  492 }
  493  
  494 void
  495 in_rtalloc(struct route *ro, u_int fibnum)
  496 {
  497         rtalloc_ign_fib(ro, 0UL, fibnum);
  498 }
  499 
  500 #if 0
  501 int      in_rt_getifa(struct rt_addrinfo *, u_int fibnum);
  502 int      in_rtioctl(u_long, caddr_t, u_int);
  503 int      in_rtrequest1(int, struct rt_addrinfo *, struct rtentry **, u_int);
  504 #endif
  505 
  506 

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