1 /*-
2 * Copyright (c) 2002 Andre Oppermann, Internet Business Solutions AG
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
13 * 3. The name of the author may not be used to endorse or promote
14 * products derived from this software without specific prior written
15 * permission.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27 * SUCH DAMAGE.
28 */
29
30 /*
31 * The tcp_hostcache moves the tcp-specific cached metrics from the routing
32 * table to a dedicated structure indexed by the remote IP address. It keeps
33 * information on the measured TCP parameters of past TCP sessions to allow
34 * better initial start values to be used with later connections to/from the
35 * same source. Depending on the network parameters (delay, max MTU,
36 * congestion window) between local and remote sites, this can lead to
37 * significant speed-ups for new TCP connections after the first one.
38 *
39 * Due to the tcp_hostcache, all TCP-specific metrics information in the
40 * routing table have been removed. The inpcb no longer keeps a pointer to
41 * the routing entry, and protocol-initiated route cloning has been removed
42 * as well. With these changes, the routing table has gone back to being
43 * more lightwight and only carries information related to packet forwarding.
44 *
45 * tcp_hostcache is designed for multiple concurrent access in SMP
46 * environments and high contention. All bucket rows have their own lock and
47 * thus multiple lookups and modifies can be done at the same time as long as
48 * they are in different bucket rows. If a request for insertion of a new
49 * record can't be satisfied, it simply returns an empty structure. Nobody
50 * and nothing outside of tcp_hostcache.c will ever point directly to any
51 * entry in the tcp_hostcache. All communication is done in an
52 * object-oriented way and only functions of tcp_hostcache will manipulate
53 * hostcache entries. Otherwise, we are unable to achieve good behaviour in
54 * concurrent access situations. Since tcp_hostcache is only caching
55 * information, there are no fatal consequences if we either can't satisfy
56 * any particular request or have to drop/overwrite an existing entry because
57 * of bucket limit memory constrains.
58 */
59
60 /*
61 * Many thanks to jlemon for basic structure of tcp_syncache which is being
62 * followed here.
63 */
64
65 #include <sys/cdefs.h>
66 __FBSDID("$FreeBSD$");
67
68 #include "opt_inet6.h"
69
70 #include <sys/param.h>
71 #include <sys/systm.h>
72 #include <sys/jail.h>
73 #include <sys/kernel.h>
74 #include <sys/lock.h>
75 #include <sys/mutex.h>
76 #include <sys/malloc.h>
77 #include <sys/proc.h>
78 #include <sys/sbuf.h>
79 #include <sys/socket.h>
80 #include <sys/socketvar.h>
81 #include <sys/sysctl.h>
82
83 #include <net/if.h>
84 #include <net/if_var.h>
85 #include <net/route.h>
86 #include <net/vnet.h>
87
88 #include <netinet/in.h>
89 #include <netinet/in_systm.h>
90 #include <netinet/ip.h>
91 #include <netinet/in_var.h>
92 #include <netinet/in_pcb.h>
93 #include <netinet/ip_var.h>
94 #ifdef INET6
95 #include <netinet/ip6.h>
96 #include <netinet6/ip6_var.h>
97 #endif
98 #include <netinet/tcp.h>
99 #include <netinet/tcp_var.h>
100 #include <netinet/tcp_hostcache.h>
101 #ifdef INET6
102 #include <netinet6/tcp6_var.h>
103 #endif
104
105 #include <vm/uma.h>
106
107 /* Arbitrary values */
108 #define TCP_HOSTCACHE_HASHSIZE 512
109 #define TCP_HOSTCACHE_BUCKETLIMIT 30
110 #define TCP_HOSTCACHE_EXPIRE 60*60 /* one hour */
111 #define TCP_HOSTCACHE_PRUNE 5*60 /* every 5 minutes */
112
113 static VNET_DEFINE(struct tcp_hostcache, tcp_hostcache);
114 #define V_tcp_hostcache VNET(tcp_hostcache)
115
116 static VNET_DEFINE(struct callout, tcp_hc_callout);
117 #define V_tcp_hc_callout VNET(tcp_hc_callout)
118
119 static struct hc_metrics *tcp_hc_lookup(struct in_conninfo *);
120 static struct hc_metrics *tcp_hc_insert(struct in_conninfo *);
121 static int sysctl_tcp_hc_list(SYSCTL_HANDLER_ARGS);
122 static int sysctl_tcp_hc_purgenow(SYSCTL_HANDLER_ARGS);
123 static void tcp_hc_purge_internal(int);
124 static void tcp_hc_purge(void *);
125
126 static SYSCTL_NODE(_net_inet_tcp, OID_AUTO, hostcache, CTLFLAG_RW, 0,
127 "TCP Host cache");
128
129 VNET_DEFINE(int, tcp_use_hostcache) = 1;
130 #define V_tcp_use_hostcache VNET(tcp_use_hostcache)
131 SYSCTL_INT(_net_inet_tcp_hostcache, OID_AUTO, enable, CTLFLAG_VNET | CTLFLAG_RW,
132 &VNET_NAME(tcp_use_hostcache), 0,
133 "Enable the TCP hostcache");
134
135 SYSCTL_UINT(_net_inet_tcp_hostcache, OID_AUTO, cachelimit, CTLFLAG_VNET | CTLFLAG_RDTUN,
136 &VNET_NAME(tcp_hostcache.cache_limit), 0,
137 "Overall entry limit for hostcache");
138
139 SYSCTL_UINT(_net_inet_tcp_hostcache, OID_AUTO, hashsize, CTLFLAG_VNET | CTLFLAG_RDTUN,
140 &VNET_NAME(tcp_hostcache.hashsize), 0,
141 "Size of TCP hostcache hashtable");
142
143 SYSCTL_UINT(_net_inet_tcp_hostcache, OID_AUTO, bucketlimit,
144 CTLFLAG_VNET | CTLFLAG_RDTUN, &VNET_NAME(tcp_hostcache.bucket_limit), 0,
145 "Per-bucket hash limit for hostcache");
146
147 SYSCTL_UINT(_net_inet_tcp_hostcache, OID_AUTO, count, CTLFLAG_VNET | CTLFLAG_RD,
148 &VNET_NAME(tcp_hostcache.cache_count), 0,
149 "Current number of entries in hostcache");
150
151 SYSCTL_INT(_net_inet_tcp_hostcache, OID_AUTO, expire, CTLFLAG_VNET | CTLFLAG_RW,
152 &VNET_NAME(tcp_hostcache.expire), 0,
153 "Expire time of TCP hostcache entries");
154
155 SYSCTL_INT(_net_inet_tcp_hostcache, OID_AUTO, prune, CTLFLAG_VNET | CTLFLAG_RW,
156 &VNET_NAME(tcp_hostcache.prune), 0,
157 "Time between purge runs");
158
159 SYSCTL_INT(_net_inet_tcp_hostcache, OID_AUTO, purge, CTLFLAG_VNET | CTLFLAG_RW,
160 &VNET_NAME(tcp_hostcache.purgeall), 0,
161 "Expire all entires on next purge run");
162
163 SYSCTL_PROC(_net_inet_tcp_hostcache, OID_AUTO, list,
164 CTLTYPE_STRING | CTLFLAG_RD | CTLFLAG_SKIP, 0, 0,
165 sysctl_tcp_hc_list, "A", "List of all hostcache entries");
166
167 SYSCTL_PROC(_net_inet_tcp_hostcache, OID_AUTO, purgenow,
168 CTLTYPE_INT | CTLFLAG_RW, NULL, 0,
169 sysctl_tcp_hc_purgenow, "I", "Immediately purge all entries");
170
171 static MALLOC_DEFINE(M_HOSTCACHE, "hostcache", "TCP hostcache");
172
173 #define HOSTCACHE_HASH(ip) \
174 (((ip)->s_addr ^ ((ip)->s_addr >> 7) ^ ((ip)->s_addr >> 17)) & \
175 V_tcp_hostcache.hashmask)
176
177 /* XXX: What is the recommended hash to get good entropy for IPv6 addresses? */
178 #define HOSTCACHE_HASH6(ip6) \
179 (((ip6)->s6_addr32[0] ^ \
180 (ip6)->s6_addr32[1] ^ \
181 (ip6)->s6_addr32[2] ^ \
182 (ip6)->s6_addr32[3]) & \
183 V_tcp_hostcache.hashmask)
184
185 #define THC_LOCK(lp) mtx_lock(lp)
186 #define THC_UNLOCK(lp) mtx_unlock(lp)
187
188 void
tcp_hc_init(void)189 tcp_hc_init(void)
190 {
191 u_int cache_limit;
192 int i;
193
194 /*
195 * Initialize hostcache structures.
196 */
197 atomic_store_int(&V_tcp_hostcache.cache_count, 0);
198 V_tcp_hostcache.hashsize = TCP_HOSTCACHE_HASHSIZE;
199 V_tcp_hostcache.bucket_limit = TCP_HOSTCACHE_BUCKETLIMIT;
200 V_tcp_hostcache.expire = TCP_HOSTCACHE_EXPIRE;
201 V_tcp_hostcache.prune = TCP_HOSTCACHE_PRUNE;
202
203 TUNABLE_INT_FETCH("net.inet.tcp.hostcache.hashsize",
204 &V_tcp_hostcache.hashsize);
205 if (!powerof2(V_tcp_hostcache.hashsize)) {
206 printf("WARNING: hostcache hash size is not a power of 2.\n");
207 V_tcp_hostcache.hashsize = TCP_HOSTCACHE_HASHSIZE; /* default */
208 }
209 V_tcp_hostcache.hashmask = V_tcp_hostcache.hashsize - 1;
210
211 TUNABLE_INT_FETCH("net.inet.tcp.hostcache.bucketlimit",
212 &V_tcp_hostcache.bucket_limit);
213
214 cache_limit = V_tcp_hostcache.hashsize * V_tcp_hostcache.bucket_limit;
215 V_tcp_hostcache.cache_limit = cache_limit;
216 TUNABLE_INT_FETCH("net.inet.tcp.hostcache.cachelimit",
217 &V_tcp_hostcache.cache_limit);
218 if (V_tcp_hostcache.cache_limit > cache_limit)
219 V_tcp_hostcache.cache_limit = cache_limit;
220
221 /*
222 * Allocate the hash table.
223 */
224 V_tcp_hostcache.hashbase = (struct hc_head *)
225 malloc(V_tcp_hostcache.hashsize * sizeof(struct hc_head),
226 M_HOSTCACHE, M_WAITOK | M_ZERO);
227
228 /*
229 * Initialize the hash buckets.
230 */
231 for (i = 0; i < V_tcp_hostcache.hashsize; i++) {
232 TAILQ_INIT(&V_tcp_hostcache.hashbase[i].hch_bucket);
233 V_tcp_hostcache.hashbase[i].hch_length = 0;
234 mtx_init(&V_tcp_hostcache.hashbase[i].hch_mtx, "tcp_hc_entry",
235 NULL, MTX_DEF);
236 }
237
238 /*
239 * Allocate the hostcache entries.
240 */
241 V_tcp_hostcache.zone =
242 uma_zcreate("hostcache", sizeof(struct hc_metrics),
243 NULL, NULL, NULL, NULL, UMA_ALIGN_PTR, 0);
244 uma_zone_set_max(V_tcp_hostcache.zone, V_tcp_hostcache.cache_limit);
245
246 /*
247 * Set up periodic cache cleanup.
248 */
249 callout_init(&V_tcp_hc_callout, 1);
250 callout_reset(&V_tcp_hc_callout, V_tcp_hostcache.prune * hz,
251 tcp_hc_purge, curvnet);
252 }
253
254 #ifdef VIMAGE
255 void
tcp_hc_destroy(void)256 tcp_hc_destroy(void)
257 {
258 int i;
259
260 callout_drain(&V_tcp_hc_callout);
261
262 /* Purge all hc entries. */
263 tcp_hc_purge_internal(1);
264
265 /* Free the uma zone and the allocated hash table. */
266 uma_zdestroy(V_tcp_hostcache.zone);
267
268 for (i = 0; i < V_tcp_hostcache.hashsize; i++)
269 mtx_destroy(&V_tcp_hostcache.hashbase[i].hch_mtx);
270 free(V_tcp_hostcache.hashbase, M_HOSTCACHE);
271 }
272 #endif
273
274 /*
275 * Internal function: look up an entry in the hostcache or return NULL.
276 *
277 * If an entry has been returned, the caller becomes responsible for
278 * unlocking the bucket row after he is done reading/modifying the entry.
279 */
280 static struct hc_metrics *
tcp_hc_lookup(struct in_conninfo * inc)281 tcp_hc_lookup(struct in_conninfo *inc)
282 {
283 int hash;
284 struct hc_head *hc_head;
285 struct hc_metrics *hc_entry;
286
287 if (!V_tcp_use_hostcache)
288 return NULL;
289
290 KASSERT(inc != NULL, ("tcp_hc_lookup with NULL in_conninfo pointer"));
291
292 /*
293 * Hash the foreign ip address.
294 */
295 if (inc->inc_flags & INC_ISIPV6)
296 hash = HOSTCACHE_HASH6(&inc->inc6_faddr);
297 else
298 hash = HOSTCACHE_HASH(&inc->inc_faddr);
299
300 hc_head = &V_tcp_hostcache.hashbase[hash];
301
302 /*
303 * Acquire lock for this bucket row; we release the lock if we don't
304 * find an entry, otherwise the caller has to unlock after he is
305 * done.
306 */
307 THC_LOCK(&hc_head->hch_mtx);
308
309 /*
310 * Iterate through entries in bucket row looking for a match.
311 */
312 TAILQ_FOREACH(hc_entry, &hc_head->hch_bucket, rmx_q) {
313 if (inc->inc_flags & INC_ISIPV6) {
314 /* XXX: check ip6_zoneid */
315 if (memcmp(&inc->inc6_faddr, &hc_entry->ip6,
316 sizeof(inc->inc6_faddr)) == 0)
317 return hc_entry;
318 } else {
319 if (memcmp(&inc->inc_faddr, &hc_entry->ip4,
320 sizeof(inc->inc_faddr)) == 0)
321 return hc_entry;
322 }
323 }
324
325 /*
326 * We were unsuccessful and didn't find anything.
327 */
328 THC_UNLOCK(&hc_head->hch_mtx);
329 return NULL;
330 }
331
332 /*
333 * Internal function: insert an entry into the hostcache or return NULL if
334 * unable to allocate a new one.
335 *
336 * If an entry has been returned, the caller becomes responsible for
337 * unlocking the bucket row after he is done reading/modifying the entry.
338 */
339 static struct hc_metrics *
tcp_hc_insert(struct in_conninfo * inc)340 tcp_hc_insert(struct in_conninfo *inc)
341 {
342 int hash;
343 struct hc_head *hc_head;
344 struct hc_metrics *hc_entry;
345
346 if (!V_tcp_use_hostcache)
347 return NULL;
348
349 KASSERT(inc != NULL, ("tcp_hc_insert with NULL in_conninfo pointer"));
350
351 /*
352 * Hash the foreign ip address.
353 */
354 if (inc->inc_flags & INC_ISIPV6)
355 hash = HOSTCACHE_HASH6(&inc->inc6_faddr);
356 else
357 hash = HOSTCACHE_HASH(&inc->inc_faddr);
358
359 hc_head = &V_tcp_hostcache.hashbase[hash];
360
361 /*
362 * Acquire lock for this bucket row; we release the lock if we don't
363 * find an entry, otherwise the caller has to unlock after he is
364 * done.
365 */
366 THC_LOCK(&hc_head->hch_mtx);
367
368 /*
369 * If the bucket limit is reached, reuse the least-used element.
370 */
371 if (hc_head->hch_length >= V_tcp_hostcache.bucket_limit ||
372 atomic_load_int(&V_tcp_hostcache.cache_count) >= V_tcp_hostcache.cache_limit) {
373 hc_entry = TAILQ_LAST(&hc_head->hch_bucket, hc_qhead);
374 /*
375 * At first we were dropping the last element, just to
376 * reacquire it in the next two lines again, which isn't very
377 * efficient. Instead just reuse the least used element.
378 * We may drop something that is still "in-use" but we can be
379 * "lossy".
380 * Just give up if this bucket row is empty and we don't have
381 * anything to replace.
382 */
383 if (hc_entry == NULL) {
384 THC_UNLOCK(&hc_head->hch_mtx);
385 return NULL;
386 }
387 TAILQ_REMOVE(&hc_head->hch_bucket, hc_entry, rmx_q);
388 V_tcp_hostcache.hashbase[hash].hch_length--;
389 atomic_subtract_int(&V_tcp_hostcache.cache_count, 1);
390 TCPSTAT_INC(tcps_hc_bucketoverflow);
391 #if 0
392 uma_zfree(V_tcp_hostcache.zone, hc_entry);
393 #endif
394 } else {
395 /*
396 * Allocate a new entry, or balk if not possible.
397 */
398 hc_entry = uma_zalloc(V_tcp_hostcache.zone, M_NOWAIT);
399 if (hc_entry == NULL) {
400 THC_UNLOCK(&hc_head->hch_mtx);
401 return NULL;
402 }
403 }
404
405 /*
406 * Initialize basic information of hostcache entry.
407 */
408 bzero(hc_entry, sizeof(*hc_entry));
409 if (inc->inc_flags & INC_ISIPV6) {
410 hc_entry->ip6 = inc->inc6_faddr;
411 hc_entry->ip6_zoneid = inc->inc6_zoneid;
412 } else
413 hc_entry->ip4 = inc->inc_faddr;
414 hc_entry->rmx_head = hc_head;
415 hc_entry->rmx_expire = V_tcp_hostcache.expire;
416
417 /*
418 * Put it upfront.
419 */
420 TAILQ_INSERT_HEAD(&hc_head->hch_bucket, hc_entry, rmx_q);
421 V_tcp_hostcache.hashbase[hash].hch_length++;
422 atomic_add_int(&V_tcp_hostcache.cache_count, 1);
423 TCPSTAT_INC(tcps_hc_added);
424
425 return hc_entry;
426 }
427
428 /*
429 * External function: look up an entry in the hostcache and fill out the
430 * supplied TCP metrics structure. Fills in NULL when no entry was found or
431 * a value is not set.
432 */
433 void
tcp_hc_get(struct in_conninfo * inc,struct hc_metrics_lite * hc_metrics_lite)434 tcp_hc_get(struct in_conninfo *inc, struct hc_metrics_lite *hc_metrics_lite)
435 {
436 struct hc_metrics *hc_entry;
437
438 if (!V_tcp_use_hostcache) {
439 bzero(hc_metrics_lite, sizeof(*hc_metrics_lite));
440 return;
441 }
442
443 /*
444 * Find the right bucket.
445 */
446 hc_entry = tcp_hc_lookup(inc);
447
448 /*
449 * If we don't have an existing object.
450 */
451 if (hc_entry == NULL) {
452 bzero(hc_metrics_lite, sizeof(*hc_metrics_lite));
453 return;
454 }
455 hc_entry->rmx_hits++;
456 hc_entry->rmx_expire = V_tcp_hostcache.expire; /* start over again */
457
458 hc_metrics_lite->rmx_mtu = hc_entry->rmx_mtu;
459 hc_metrics_lite->rmx_ssthresh = hc_entry->rmx_ssthresh;
460 hc_metrics_lite->rmx_rtt = hc_entry->rmx_rtt;
461 hc_metrics_lite->rmx_rttvar = hc_entry->rmx_rttvar;
462 hc_metrics_lite->rmx_cwnd = hc_entry->rmx_cwnd;
463 hc_metrics_lite->rmx_sendpipe = hc_entry->rmx_sendpipe;
464 hc_metrics_lite->rmx_recvpipe = hc_entry->rmx_recvpipe;
465
466 /*
467 * Unlock bucket row.
468 */
469 THC_UNLOCK(&hc_entry->rmx_head->hch_mtx);
470 }
471
472 /*
473 * External function: look up an entry in the hostcache and return the
474 * discovered path MTU. Returns 0 if no entry is found or value is not
475 * set.
476 */
477 u_long
tcp_hc_getmtu(struct in_conninfo * inc)478 tcp_hc_getmtu(struct in_conninfo *inc)
479 {
480 struct hc_metrics *hc_entry;
481 u_long mtu;
482
483 if (!V_tcp_use_hostcache)
484 return 0;
485
486 hc_entry = tcp_hc_lookup(inc);
487 if (hc_entry == NULL) {
488 return 0;
489 }
490 hc_entry->rmx_hits++;
491 hc_entry->rmx_expire = V_tcp_hostcache.expire; /* start over again */
492
493 mtu = hc_entry->rmx_mtu;
494 THC_UNLOCK(&hc_entry->rmx_head->hch_mtx);
495 return mtu;
496 }
497
498 /*
499 * External function: update the MTU value of an entry in the hostcache.
500 * Creates a new entry if none was found.
501 */
502 void
tcp_hc_updatemtu(struct in_conninfo * inc,u_long mtu)503 tcp_hc_updatemtu(struct in_conninfo *inc, u_long mtu)
504 {
505 struct hc_metrics *hc_entry;
506
507 if (!V_tcp_use_hostcache)
508 return;
509
510 /*
511 * Find the right bucket.
512 */
513 hc_entry = tcp_hc_lookup(inc);
514
515 /*
516 * If we don't have an existing object, try to insert a new one.
517 */
518 if (hc_entry == NULL) {
519 hc_entry = tcp_hc_insert(inc);
520 if (hc_entry == NULL)
521 return;
522 }
523 hc_entry->rmx_updates++;
524 hc_entry->rmx_expire = V_tcp_hostcache.expire; /* start over again */
525
526 hc_entry->rmx_mtu = mtu;
527
528 /*
529 * Put it upfront so we find it faster next time.
530 */
531 TAILQ_REMOVE(&hc_entry->rmx_head->hch_bucket, hc_entry, rmx_q);
532 TAILQ_INSERT_HEAD(&hc_entry->rmx_head->hch_bucket, hc_entry, rmx_q);
533
534 /*
535 * Unlock bucket row.
536 */
537 THC_UNLOCK(&hc_entry->rmx_head->hch_mtx);
538 }
539
540 /*
541 * External function: update the TCP metrics of an entry in the hostcache.
542 * Creates a new entry if none was found.
543 */
544 void
tcp_hc_update(struct in_conninfo * inc,struct hc_metrics_lite * hcml)545 tcp_hc_update(struct in_conninfo *inc, struct hc_metrics_lite *hcml)
546 {
547 struct hc_metrics *hc_entry;
548
549 if (!V_tcp_use_hostcache)
550 return;
551
552 hc_entry = tcp_hc_lookup(inc);
553 if (hc_entry == NULL) {
554 hc_entry = tcp_hc_insert(inc);
555 if (hc_entry == NULL)
556 return;
557 }
558 hc_entry->rmx_updates++;
559 hc_entry->rmx_expire = V_tcp_hostcache.expire; /* start over again */
560
561 if (hcml->rmx_rtt != 0) {
562 if (hc_entry->rmx_rtt == 0)
563 hc_entry->rmx_rtt = hcml->rmx_rtt;
564 else
565 hc_entry->rmx_rtt =
566 (hc_entry->rmx_rtt + hcml->rmx_rtt) / 2;
567 TCPSTAT_INC(tcps_cachedrtt);
568 }
569 if (hcml->rmx_rttvar != 0) {
570 if (hc_entry->rmx_rttvar == 0)
571 hc_entry->rmx_rttvar = hcml->rmx_rttvar;
572 else
573 hc_entry->rmx_rttvar =
574 (hc_entry->rmx_rttvar + hcml->rmx_rttvar) / 2;
575 TCPSTAT_INC(tcps_cachedrttvar);
576 }
577 if (hcml->rmx_ssthresh != 0) {
578 if (hc_entry->rmx_ssthresh == 0)
579 hc_entry->rmx_ssthresh = hcml->rmx_ssthresh;
580 else
581 hc_entry->rmx_ssthresh =
582 (hc_entry->rmx_ssthresh + hcml->rmx_ssthresh) / 2;
583 TCPSTAT_INC(tcps_cachedssthresh);
584 }
585 if (hcml->rmx_cwnd != 0) {
586 if (hc_entry->rmx_cwnd == 0)
587 hc_entry->rmx_cwnd = hcml->rmx_cwnd;
588 else
589 hc_entry->rmx_cwnd =
590 (hc_entry->rmx_cwnd + hcml->rmx_cwnd) / 2;
591 /* TCPSTAT_INC(tcps_cachedcwnd); */
592 }
593 if (hcml->rmx_sendpipe != 0) {
594 if (hc_entry->rmx_sendpipe == 0)
595 hc_entry->rmx_sendpipe = hcml->rmx_sendpipe;
596 else
597 hc_entry->rmx_sendpipe =
598 (hc_entry->rmx_sendpipe + hcml->rmx_sendpipe) /2;
599 /* TCPSTAT_INC(tcps_cachedsendpipe); */
600 }
601 if (hcml->rmx_recvpipe != 0) {
602 if (hc_entry->rmx_recvpipe == 0)
603 hc_entry->rmx_recvpipe = hcml->rmx_recvpipe;
604 else
605 hc_entry->rmx_recvpipe =
606 (hc_entry->rmx_recvpipe + hcml->rmx_recvpipe) /2;
607 /* TCPSTAT_INC(tcps_cachedrecvpipe); */
608 }
609
610 TAILQ_REMOVE(&hc_entry->rmx_head->hch_bucket, hc_entry, rmx_q);
611 TAILQ_INSERT_HEAD(&hc_entry->rmx_head->hch_bucket, hc_entry, rmx_q);
612 THC_UNLOCK(&hc_entry->rmx_head->hch_mtx);
613 }
614
615 /*
616 * Sysctl function: prints the list and values of all hostcache entries in
617 * unsorted order.
618 */
619 static int
sysctl_tcp_hc_list(SYSCTL_HANDLER_ARGS)620 sysctl_tcp_hc_list(SYSCTL_HANDLER_ARGS)
621 {
622 const int linesize = 128;
623 struct sbuf sb;
624 int i, error, len;
625 struct hc_metrics *hc_entry;
626 char ip4buf[INET_ADDRSTRLEN];
627 #ifdef INET6
628 char ip6buf[INET6_ADDRSTRLEN];
629 #endif
630
631 if (jailed_without_vnet(curthread->td_ucred) != 0)
632 return (EPERM);
633
634 /* Optimize Buffer length query by sbin/sysctl */
635 if (req->oldptr == NULL) {
636 len = (atomic_load_int(&V_tcp_hostcache.cache_count) + 1) *
637 linesize;
638 return (SYSCTL_OUT(req, NULL, len));
639 }
640
641 error = sysctl_wire_old_buffer(req, 0);
642 if (error != 0) {
643 return(error);
644 }
645
646 /* Use a buffer sized for one full bucket */
647 sbuf_new_for_sysctl(&sb, NULL, V_tcp_hostcache.bucket_limit *
648 linesize, req);
649
650 sbuf_printf(&sb,
651 "\nIP address MTU SSTRESH RTT RTTVAR "
652 " CWND SENDPIPE RECVPIPE HITS UPD EXP\n");
653 sbuf_drain(&sb);
654
655 #define msec(u) (((u) + 500) / 1000)
656 for (i = 0; i < V_tcp_hostcache.hashsize; i++) {
657 THC_LOCK(&V_tcp_hostcache.hashbase[i].hch_mtx);
658 TAILQ_FOREACH(hc_entry, &V_tcp_hostcache.hashbase[i].hch_bucket,
659 rmx_q) {
660 sbuf_printf(&sb,
661 "%-15s %5lu %8lu %6lums %6lums %8lu %8lu %8lu %4lu "
662 "%4lu %4i\n",
663 hc_entry->ip4.s_addr ?
664 inet_ntoa_r(hc_entry->ip4, ip4buf) :
665 #ifdef INET6
666 ip6_sprintf(ip6buf, &hc_entry->ip6),
667 #else
668 "IPv6?",
669 #endif
670 hc_entry->rmx_mtu,
671 hc_entry->rmx_ssthresh,
672 msec(hc_entry->rmx_rtt *
673 (RTM_RTTUNIT / (hz * TCP_RTT_SCALE))),
674 msec(hc_entry->rmx_rttvar *
675 (RTM_RTTUNIT / (hz * TCP_RTTVAR_SCALE))),
676 hc_entry->rmx_cwnd,
677 hc_entry->rmx_sendpipe,
678 hc_entry->rmx_recvpipe,
679 hc_entry->rmx_hits,
680 hc_entry->rmx_updates,
681 hc_entry->rmx_expire);
682 }
683 THC_UNLOCK(&V_tcp_hostcache.hashbase[i].hch_mtx);
684 sbuf_drain(&sb);
685 }
686 #undef msec
687 error = sbuf_finish(&sb);
688 sbuf_delete(&sb);
689 return(error);
690 }
691
692 /*
693 * Caller has to make sure the curvnet is set properly.
694 */
695 static void
tcp_hc_purge_internal(int all)696 tcp_hc_purge_internal(int all)
697 {
698 struct hc_metrics *hc_entry, *hc_next;
699 int i;
700
701 for (i = 0; i < V_tcp_hostcache.hashsize; i++) {
702 THC_LOCK(&V_tcp_hostcache.hashbase[i].hch_mtx);
703 TAILQ_FOREACH_SAFE(hc_entry,
704 &V_tcp_hostcache.hashbase[i].hch_bucket, rmx_q, hc_next) {
705 if (all || hc_entry->rmx_expire <= 0) {
706 TAILQ_REMOVE(&V_tcp_hostcache.hashbase[i].hch_bucket,
707 hc_entry, rmx_q);
708 uma_zfree(V_tcp_hostcache.zone, hc_entry);
709 V_tcp_hostcache.hashbase[i].hch_length--;
710 atomic_subtract_int(&V_tcp_hostcache.cache_count, 1);
711 } else
712 hc_entry->rmx_expire -= V_tcp_hostcache.prune;
713 }
714 THC_UNLOCK(&V_tcp_hostcache.hashbase[i].hch_mtx);
715 }
716 }
717
718 /*
719 * Expire and purge (old|all) entries in the tcp_hostcache. Runs
720 * periodically from the callout.
721 */
722 static void
tcp_hc_purge(void * arg)723 tcp_hc_purge(void *arg)
724 {
725 CURVNET_SET((struct vnet *) arg);
726 int all = 0;
727
728 if (V_tcp_hostcache.purgeall) {
729 all = 1;
730 V_tcp_hostcache.purgeall = 0;
731 }
732
733 tcp_hc_purge_internal(all);
734
735 callout_reset(&V_tcp_hc_callout, V_tcp_hostcache.prune * hz,
736 tcp_hc_purge, arg);
737 CURVNET_RESTORE();
738 }
739
740 /*
741 * Expire and purge all entries in hostcache immediately.
742 */
743 static int
sysctl_tcp_hc_purgenow(SYSCTL_HANDLER_ARGS)744 sysctl_tcp_hc_purgenow(SYSCTL_HANDLER_ARGS)
745 {
746 int error, val;
747
748 val = 0;
749 error = sysctl_handle_int(oidp, &val, 0, req);
750 if (error || !req->newptr)
751 return (error);
752
753 tcp_hc_purge_internal(1);
754
755 callout_reset(&V_tcp_hc_callout, V_tcp_hostcache.prune * hz,
756 tcp_hc_purge, curvnet);
757
758 return (0);
759 }
760