FreeBSD/Linux Kernel Cross Reference
sys/netinet/in_rmx.c
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 /*
31 * This code does two things necessary for the enhanced TCP metrics to
32 * function in a useful manner:
33 * 1) It marks all non-host routes as `cloning', thus ensuring that
34 * every actual reference to such a route actually gets turned
35 * into a reference to a host route to the specific destination
36 * requested.
37 * 2) When such routes lose all their references, it arranges for them
38 * to be deleted in some random collection of circumstances, so that
39 * a large quantity of stale routing data is not kept in kernel memory
40 * indefinitely. See in_rtqtimo() below for the exact mechanism.
41 */
42
43 #include <sys/cdefs.h>
44 __FBSDID("$FreeBSD: releng/8.3/sys/netinet/in_rmx.c 213687 2010-10-11 11:25:37Z delphij $");
45
46 #include <sys/param.h>
47 #include <sys/systm.h>
48 #include <sys/kernel.h>
49 #include <sys/sysctl.h>
50 #include <sys/socket.h>
51 #include <sys/mbuf.h>
52 #include <sys/syslog.h>
53 #include <sys/callout.h>
54
55 #include <net/if.h>
56 #include <net/route.h>
57 #include <net/vnet.h>
58
59 #include <netinet/in.h>
60 #include <netinet/in_var.h>
61 #include <netinet/ip_var.h>
62
63 extern int in_inithead(void **head, int off);
64 #ifdef VIMAGE
65 extern int in_detachhead(void **head, int off);
66 #endif
67
68 #define RTPRF_OURS RTF_PROTO3 /* set on routes we manage */
69
70 /*
71 * Do what we need to do when inserting a route.
72 */
73 static struct radix_node *
74 in_addroute(void *v_arg, void *n_arg, struct radix_node_head *head,
75 struct radix_node *treenodes)
76 {
77 struct rtentry *rt = (struct rtentry *)treenodes;
78 struct sockaddr_in *sin = (struct sockaddr_in *)rt_key(rt);
79
80 RADIX_NODE_HEAD_WLOCK_ASSERT(head);
81 /*
82 * A little bit of help for both IP output and input:
83 * For host routes, we make sure that RTF_BROADCAST
84 * is set for anything that looks like a broadcast address.
85 * This way, we can avoid an expensive call to in_broadcast()
86 * in ip_output() most of the time (because the route passed
87 * to ip_output() is almost always a host route).
88 *
89 * We also do the same for local addresses, with the thought
90 * that this might one day be used to speed up ip_input().
91 *
92 * We also mark routes to multicast addresses as such, because
93 * it's easy to do and might be useful (but this is much more
94 * dubious since it's so easy to inspect the address).
95 */
96 if (rt->rt_flags & RTF_HOST) {
97 if (in_broadcast(sin->sin_addr, rt->rt_ifp)) {
98 rt->rt_flags |= RTF_BROADCAST;
99 } else if (satosin(rt->rt_ifa->ifa_addr)->sin_addr.s_addr ==
100 sin->sin_addr.s_addr) {
101 rt->rt_flags |= RTF_LOCAL;
102 }
103 }
104 if (IN_MULTICAST(ntohl(sin->sin_addr.s_addr)))
105 rt->rt_flags |= RTF_MULTICAST;
106
107 if (!rt->rt_rmx.rmx_mtu && rt->rt_ifp)
108 rt->rt_rmx.rmx_mtu = rt->rt_ifp->if_mtu;
109
110 return (rn_addroute(v_arg, n_arg, head, treenodes));
111 }
112
113 /*
114 * This code is the inverse of in_clsroute: on first reference, if we
115 * were managing the route, stop doing so and set the expiration timer
116 * back off again.
117 */
118 static struct radix_node *
119 in_matroute(void *v_arg, struct radix_node_head *head)
120 {
121 struct radix_node *rn = rn_match(v_arg, head);
122 struct rtentry *rt = (struct rtentry *)rn;
123
124 if (rt) {
125 RT_LOCK(rt);
126 if (rt->rt_flags & RTPRF_OURS) {
127 rt->rt_flags &= ~RTPRF_OURS;
128 rt->rt_rmx.rmx_expire = 0;
129 }
130 RT_UNLOCK(rt);
131 }
132 return rn;
133 }
134
135 static VNET_DEFINE(int, rtq_reallyold) = 60*60; /* one hour is "really old" */
136 #define V_rtq_reallyold VNET(rtq_reallyold)
137 SYSCTL_VNET_INT(_net_inet_ip, IPCTL_RTEXPIRE, rtexpire, CTLFLAG_RW,
138 &VNET_NAME(rtq_reallyold), 0,
139 "Default expiration time on dynamically learned routes");
140
141 /* never automatically crank down to less */
142 static VNET_DEFINE(int, rtq_minreallyold) = 10;
143 #define V_rtq_minreallyold VNET(rtq_minreallyold)
144 SYSCTL_VNET_INT(_net_inet_ip, IPCTL_RTMINEXPIRE, rtminexpire, CTLFLAG_RW,
145 &VNET_NAME(rtq_minreallyold), 0,
146 "Minimum time to attempt to hold onto dynamically learned routes");
147
148 /* 128 cached routes is "too many" */
149 static VNET_DEFINE(int, rtq_toomany) = 128;
150 #define V_rtq_toomany VNET(rtq_toomany)
151 SYSCTL_VNET_INT(_net_inet_ip, IPCTL_RTMAXCACHE, rtmaxcache, CTLFLAG_RW,
152 &VNET_NAME(rtq_toomany), 0,
153 "Upper limit on dynamically learned routes");
154
155 /*
156 * On last reference drop, mark the route as belong to us so that it can be
157 * timed out.
158 */
159 static void
160 in_clsroute(struct radix_node *rn, struct radix_node_head *head)
161 {
162 struct rtentry *rt = (struct rtentry *)rn;
163
164 RT_LOCK_ASSERT(rt);
165
166 if (!(rt->rt_flags & RTF_UP))
167 return; /* prophylactic measures */
168
169 if (rt->rt_flags & RTPRF_OURS)
170 return;
171
172 if (!(rt->rt_flags & RTF_DYNAMIC))
173 return;
174
175 /*
176 * If rtq_reallyold is 0, just delete the route without
177 * waiting for a timeout cycle to kill it.
178 */
179 if (V_rtq_reallyold != 0) {
180 rt->rt_flags |= RTPRF_OURS;
181 rt->rt_rmx.rmx_expire = time_uptime + V_rtq_reallyold;
182 } else {
183 rtexpunge(rt);
184 }
185 }
186
187 struct rtqk_arg {
188 struct radix_node_head *rnh;
189 int draining;
190 int killed;
191 int found;
192 int updating;
193 time_t nextstop;
194 };
195
196 /*
197 * Get rid of old routes. When draining, this deletes everything, even when
198 * the timeout is not expired yet. When updating, this makes sure that
199 * nothing has a timeout longer than the current value of rtq_reallyold.
200 */
201 static int
202 in_rtqkill(struct radix_node *rn, void *rock)
203 {
204 struct rtqk_arg *ap = rock;
205 struct rtentry *rt = (struct rtentry *)rn;
206 int err;
207
208 RADIX_NODE_HEAD_WLOCK_ASSERT(ap->rnh);
209
210 if (rt->rt_flags & RTPRF_OURS) {
211 ap->found++;
212
213 if (ap->draining || rt->rt_rmx.rmx_expire <= time_uptime) {
214 if (rt->rt_refcnt > 0)
215 panic("rtqkill route really not free");
216
217 err = in_rtrequest(RTM_DELETE,
218 (struct sockaddr *)rt_key(rt),
219 rt->rt_gateway, rt_mask(rt),
220 rt->rt_flags | RTF_RNH_LOCKED, 0,
221 rt->rt_fibnum);
222 if (err) {
223 log(LOG_WARNING, "in_rtqkill: error %d\n", err);
224 } else {
225 ap->killed++;
226 }
227 } else {
228 if (ap->updating &&
229 (rt->rt_rmx.rmx_expire - time_uptime >
230 V_rtq_reallyold)) {
231 rt->rt_rmx.rmx_expire =
232 time_uptime + V_rtq_reallyold;
233 }
234 ap->nextstop = lmin(ap->nextstop,
235 rt->rt_rmx.rmx_expire);
236 }
237 }
238
239 return 0;
240 }
241
242 #define RTQ_TIMEOUT 60*10 /* run no less than once every ten minutes */
243 static VNET_DEFINE(int, rtq_timeout) = RTQ_TIMEOUT;
244 static VNET_DEFINE(struct callout, rtq_timer);
245
246 #define V_rtq_timeout VNET(rtq_timeout)
247 #define V_rtq_timer VNET(rtq_timer)
248
249 static void in_rtqtimo_one(void *rock);
250
251 static void
252 in_rtqtimo(void *rock)
253 {
254 CURVNET_SET((struct vnet *) rock);
255 int fibnum;
256 void *newrock;
257 struct timeval atv;
258
259 for (fibnum = 0; fibnum < rt_numfibs; fibnum++) {
260 newrock = rt_tables_get_rnh(fibnum, AF_INET);
261 if (newrock != NULL)
262 in_rtqtimo_one(newrock);
263 }
264 atv.tv_usec = 0;
265 atv.tv_sec = V_rtq_timeout;
266 callout_reset(&V_rtq_timer, tvtohz(&atv), in_rtqtimo, rock);
267 CURVNET_RESTORE();
268 }
269
270 static void
271 in_rtqtimo_one(void *rock)
272 {
273 struct radix_node_head *rnh = rock;
274 struct rtqk_arg arg;
275 static time_t last_adjusted_timeout = 0;
276
277 arg.found = arg.killed = 0;
278 arg.rnh = rnh;
279 arg.nextstop = time_uptime + V_rtq_timeout;
280 arg.draining = arg.updating = 0;
281 RADIX_NODE_HEAD_LOCK(rnh);
282 rnh->rnh_walktree(rnh, in_rtqkill, &arg);
283 RADIX_NODE_HEAD_UNLOCK(rnh);
284
285 /*
286 * Attempt to be somewhat dynamic about this:
287 * If there are ``too many'' routes sitting around taking up space,
288 * then crank down the timeout, and see if we can't make some more
289 * go away. However, we make sure that we will never adjust more
290 * than once in rtq_timeout seconds, to keep from cranking down too
291 * hard.
292 */
293 if ((arg.found - arg.killed > V_rtq_toomany) &&
294 (time_uptime - last_adjusted_timeout >= V_rtq_timeout) &&
295 V_rtq_reallyold > V_rtq_minreallyold) {
296 V_rtq_reallyold = 2 * V_rtq_reallyold / 3;
297 if (V_rtq_reallyold < V_rtq_minreallyold) {
298 V_rtq_reallyold = V_rtq_minreallyold;
299 }
300
301 last_adjusted_timeout = time_uptime;
302 #ifdef DIAGNOSTIC
303 log(LOG_DEBUG, "in_rtqtimo: adjusted rtq_reallyold to %d\n",
304 V_rtq_reallyold);
305 #endif
306 arg.found = arg.killed = 0;
307 arg.updating = 1;
308 RADIX_NODE_HEAD_LOCK(rnh);
309 rnh->rnh_walktree(rnh, in_rtqkill, &arg);
310 RADIX_NODE_HEAD_UNLOCK(rnh);
311 }
312
313 }
314
315 void
316 in_rtqdrain(void)
317 {
318 VNET_ITERATOR_DECL(vnet_iter);
319 struct radix_node_head *rnh;
320 struct rtqk_arg arg;
321 int fibnum;
322
323 VNET_LIST_RLOCK_NOSLEEP();
324 VNET_FOREACH(vnet_iter) {
325 CURVNET_SET(vnet_iter);
326
327 for ( fibnum = 0; fibnum < rt_numfibs; fibnum++) {
328 rnh = rt_tables_get_rnh(fibnum, AF_INET);
329 arg.found = arg.killed = 0;
330 arg.rnh = rnh;
331 arg.nextstop = 0;
332 arg.draining = 1;
333 arg.updating = 0;
334 RADIX_NODE_HEAD_LOCK(rnh);
335 rnh->rnh_walktree(rnh, in_rtqkill, &arg);
336 RADIX_NODE_HEAD_UNLOCK(rnh);
337 }
338 CURVNET_RESTORE();
339 }
340 VNET_LIST_RUNLOCK_NOSLEEP();
341 }
342
343 static int _in_rt_was_here;
344 /*
345 * Initialize our routing tree.
346 */
347 int
348 in_inithead(void **head, int off)
349 {
350 struct radix_node_head *rnh;
351
352 /* XXX MRT
353 * This can be called from vfs_export.c too in which case 'off'
354 * will be 0. We know the correct value so just use that and
355 * return directly if it was 0.
356 * This is a hack that replaces an even worse hack on a bad hack
357 * on a bad design. After RELENG_7 this should be fixed but that
358 * will change the ABI, so for now do it this way.
359 */
360 if (!rn_inithead(head, 32))
361 return 0;
362
363 if (off == 0) /* XXX MRT see above */
364 return 1; /* only do the rest for a real routing table */
365
366 rnh = *head;
367 rnh->rnh_addaddr = in_addroute;
368 rnh->rnh_matchaddr = in_matroute;
369 rnh->rnh_close = in_clsroute;
370 if (_in_rt_was_here == 0 ) {
371 callout_init(&V_rtq_timer, CALLOUT_MPSAFE);
372 callout_reset(&V_rtq_timer, 1, in_rtqtimo, curvnet);
373 _in_rt_was_here = 1;
374 }
375 return 1;
376 }
377
378 #ifdef VIMAGE
379 int
380 in_detachhead(void **head, int off)
381 {
382
383 callout_drain(&V_rtq_timer);
384 return (1);
385 }
386 #endif
387
388 /*
389 * This zaps old routes when the interface goes down or interface
390 * address is deleted. In the latter case, it deletes static routes
391 * that point to this address. If we don't do this, we may end up
392 * using the old address in the future. The ones we always want to
393 * get rid of are things like ARP entries, since the user might down
394 * the interface, walk over to a completely different network, and
395 * plug back in.
396 */
397 struct in_ifadown_arg {
398 struct ifaddr *ifa;
399 int del;
400 };
401
402 static int
403 in_ifadownkill(struct radix_node *rn, void *xap)
404 {
405 struct in_ifadown_arg *ap = xap;
406 struct rtentry *rt = (struct rtentry *)rn;
407
408 RT_LOCK(rt);
409 if (rt->rt_ifa == ap->ifa &&
410 (ap->del || !(rt->rt_flags & RTF_STATIC))) {
411 /*
412 * Aquire a reference so that it can later be freed
413 * as the refcount would be 0 here in case of at least
414 * ap->del.
415 */
416 RT_ADDREF(rt);
417 /*
418 * Disconnect it from the tree and permit protocols
419 * to cleanup.
420 */
421 rtexpunge(rt);
422 /*
423 * At this point it is an rttrash node, and in case
424 * the above is the only reference we must free it.
425 * If we do not noone will have a pointer and the
426 * rtentry will be leaked forever.
427 * In case someone else holds a reference, we are
428 * fine as we only decrement the refcount. In that
429 * case if the other entity calls RT_REMREF, we
430 * will still be leaking but at least we tried.
431 */
432 RTFREE_LOCKED(rt);
433 return (0);
434 }
435 RT_UNLOCK(rt);
436 return 0;
437 }
438
439 int
440 in_ifadown(struct ifaddr *ifa, int delete)
441 {
442 struct in_ifadown_arg arg;
443 struct radix_node_head *rnh;
444 int fibnum;
445
446 if (ifa->ifa_addr->sa_family != AF_INET)
447 return 1;
448
449 for ( fibnum = 0; fibnum < rt_numfibs; fibnum++) {
450 rnh = rt_tables_get_rnh(fibnum, AF_INET);
451 arg.ifa = ifa;
452 arg.del = delete;
453 RADIX_NODE_HEAD_LOCK(rnh);
454 rnh->rnh_walktree(rnh, in_ifadownkill, &arg);
455 RADIX_NODE_HEAD_UNLOCK(rnh);
456 ifa->ifa_flags &= ~IFA_ROUTE; /* XXXlocking? */
457 }
458 return 0;
459 }
460
461 /*
462 * inet versions of rt functions. These have fib extensions and
463 * for now will just reference the _fib variants.
464 * eventually this order will be reversed,
465 */
466 void
467 in_rtalloc_ign(struct route *ro, u_long ignflags, u_int fibnum)
468 {
469 rtalloc_ign_fib(ro, ignflags, fibnum);
470 }
471
472 int
473 in_rtrequest( int req,
474 struct sockaddr *dst,
475 struct sockaddr *gateway,
476 struct sockaddr *netmask,
477 int flags,
478 struct rtentry **ret_nrt,
479 u_int fibnum)
480 {
481 return (rtrequest_fib(req, dst, gateway, netmask,
482 flags, ret_nrt, fibnum));
483 }
484
485 struct rtentry *
486 in_rtalloc1(struct sockaddr *dst, int report, u_long ignflags, u_int fibnum)
487 {
488 return (rtalloc1_fib(dst, report, ignflags, fibnum));
489 }
490
491 void
492 in_rtredirect(struct sockaddr *dst,
493 struct sockaddr *gateway,
494 struct sockaddr *netmask,
495 int flags,
496 struct sockaddr *src,
497 u_int fibnum)
498 {
499 rtredirect_fib(dst, gateway, netmask, flags, src, fibnum);
500 }
501
502 void
503 in_rtalloc(struct route *ro, u_int fibnum)
504 {
505 rtalloc_ign_fib(ro, 0UL, fibnum);
506 }
507
508 #if 0
509 int in_rt_getifa(struct rt_addrinfo *, u_int fibnum);
510 int in_rtioctl(u_long, caddr_t, u_int);
511 int in_rtrequest1(int, struct rt_addrinfo *, struct rtentry **, u_int);
512 #endif
513
514
Cache object: c4327f90fa363a07940178089f9c8a14
|