1 /*-
2 * SPDX-License-Identifier: BSD-3-Clause
3 *
4 * Copyright (c) 2002 Andre Oppermann, Internet Business Solutions AG
5 * All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
15 * 3. The name of the author may not be used to endorse or promote
16 * products derived from this software without specific prior written
17 * permission.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29 * SUCH DAMAGE.
30 */
31
32 /*
33 * The tcp_hostcache moves the tcp-specific cached metrics from the routing
34 * table to a dedicated structure indexed by the remote IP address. It keeps
35 * information on the measured TCP parameters of past TCP sessions to allow
36 * better initial start values to be used with later connections to/from the
37 * same source. Depending on the network parameters (delay, max MTU,
38 * congestion window) between local and remote sites, this can lead to
39 * significant speed-ups for new TCP connections after the first one.
40 *
41 * Due to the tcp_hostcache, all TCP-specific metrics information in the
42 * routing table have been removed. The inpcb no longer keeps a pointer to
43 * the routing entry, and protocol-initiated route cloning has been removed
44 * as well. With these changes, the routing table has gone back to being
45 * more lightwight and only carries information related to packet forwarding.
46 *
47 * tcp_hostcache is designed for multiple concurrent access in SMP
48 * environments and high contention. All bucket rows have their own lock and
49 * thus multiple lookups and modifies can be done at the same time as long as
50 * they are in different bucket rows. If a request for insertion of a new
51 * record can't be satisfied, it simply returns an empty structure. Nobody
52 * and nothing outside of tcp_hostcache.c will ever point directly to any
53 * entry in the tcp_hostcache. All communication is done in an
54 * object-oriented way and only functions of tcp_hostcache will manipulate
55 * hostcache entries. Otherwise, we are unable to achieve good behaviour in
56 * concurrent access situations. Since tcp_hostcache is only caching
57 * information, there are no fatal consequences if we either can't satisfy
58 * any particular request or have to drop/overwrite an existing entry because
59 * of bucket limit memory constrains.
60 */
61
62 /*
63 * Many thanks to jlemon for basic structure of tcp_syncache which is being
64 * followed here.
65 */
66
67 #include <sys/cdefs.h>
68 #include "opt_inet6.h"
69
70 #include <sys/param.h>
71 #include <sys/systm.h>
72 #include <sys/hash.h>
73 #include <sys/jail.h>
74 #include <sys/kernel.h>
75 #include <sys/lock.h>
76 #include <sys/mutex.h>
77 #include <sys/malloc.h>
78 #include <sys/proc.h>
79 #include <sys/sbuf.h>
80 #include <sys/socket.h>
81 #include <sys/socketvar.h>
82 #include <sys/sysctl.h>
83
84 #include <net/if.h>
85 #include <net/if_var.h>
86 #include <net/route.h>
87 #include <net/vnet.h>
88
89 #include <netinet/in.h>
90 #include <netinet/in_systm.h>
91 #include <netinet/ip.h>
92 #include <netinet/in_var.h>
93 #include <netinet/in_pcb.h>
94 #include <netinet/ip_var.h>
95 #ifdef INET6
96 #include <netinet/ip6.h>
97 #include <netinet6/ip6_var.h>
98 #endif
99 #include <netinet/tcp.h>
100 #include <netinet/tcp_var.h>
101 #include <netinet/tcp_hostcache.h>
102 #ifdef INET6
103 #include <netinet6/tcp6_var.h>
104 #endif
105
106 #include <vm/uma.h>
107
108 /* Arbitrary values */
109 #define TCP_HOSTCACHE_HASHSIZE 512
110 #define TCP_HOSTCACHE_BUCKETLIMIT 30
111 #define TCP_HOSTCACHE_EXPIRE 60*60 /* one hour */
112 #define TCP_HOSTCACHE_PRUNE 5*60 /* every 5 minutes */
113
114 VNET_DEFINE_STATIC(struct tcp_hostcache, tcp_hostcache);
115 #define V_tcp_hostcache VNET(tcp_hostcache)
116
117 VNET_DEFINE_STATIC(struct callout, tcp_hc_callout);
118 #define V_tcp_hc_callout VNET(tcp_hc_callout)
119
120 static struct hc_metrics *tcp_hc_lookup(struct in_conninfo *);
121 static struct hc_metrics *tcp_hc_insert(struct in_conninfo *);
122 static int sysctl_tcp_hc_list(SYSCTL_HANDLER_ARGS);
123 static int sysctl_tcp_hc_histo(SYSCTL_HANDLER_ARGS);
124 static int sysctl_tcp_hc_purgenow(SYSCTL_HANDLER_ARGS);
125 static void tcp_hc_purge_internal(int);
126 static void tcp_hc_purge(void *);
127
128 static SYSCTL_NODE(_net_inet_tcp, OID_AUTO, hostcache,
129 CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
130 "TCP Host cache");
131
132 VNET_DEFINE(int, tcp_use_hostcache) = 1;
133 #define V_tcp_use_hostcache VNET(tcp_use_hostcache)
134 SYSCTL_INT(_net_inet_tcp_hostcache, OID_AUTO, enable, CTLFLAG_VNET | CTLFLAG_RW,
135 &VNET_NAME(tcp_use_hostcache), 0,
136 "Enable the TCP hostcache");
137
138 SYSCTL_UINT(_net_inet_tcp_hostcache, OID_AUTO, cachelimit, CTLFLAG_VNET | CTLFLAG_RDTUN,
139 &VNET_NAME(tcp_hostcache.cache_limit), 0,
140 "Overall entry limit for hostcache");
141
142 SYSCTL_UINT(_net_inet_tcp_hostcache, OID_AUTO, hashsize, CTLFLAG_VNET | CTLFLAG_RDTUN,
143 &VNET_NAME(tcp_hostcache.hashsize), 0,
144 "Size of TCP hostcache hashtable");
145
146 SYSCTL_UINT(_net_inet_tcp_hostcache, OID_AUTO, bucketlimit,
147 CTLFLAG_VNET | CTLFLAG_RDTUN, &VNET_NAME(tcp_hostcache.bucket_limit), 0,
148 "Per-bucket hash limit for hostcache");
149
150 SYSCTL_UINT(_net_inet_tcp_hostcache, OID_AUTO, count, CTLFLAG_VNET | CTLFLAG_RD,
151 &VNET_NAME(tcp_hostcache.cache_count), 0,
152 "Current number of entries in hostcache");
153
154 SYSCTL_INT(_net_inet_tcp_hostcache, OID_AUTO, expire, CTLFLAG_VNET | CTLFLAG_RW,
155 &VNET_NAME(tcp_hostcache.expire), 0,
156 "Expire time of TCP hostcache entries");
157
158 SYSCTL_INT(_net_inet_tcp_hostcache, OID_AUTO, prune, CTLFLAG_VNET | CTLFLAG_RW,
159 &VNET_NAME(tcp_hostcache.prune), 0,
160 "Time between purge runs");
161
162 SYSCTL_INT(_net_inet_tcp_hostcache, OID_AUTO, purge, CTLFLAG_VNET | CTLFLAG_RW,
163 &VNET_NAME(tcp_hostcache.purgeall), 0,
164 "Expire all entries on next purge run");
165
166 SYSCTL_PROC(_net_inet_tcp_hostcache, OID_AUTO, list,
167 CTLTYPE_STRING | CTLFLAG_RD | CTLFLAG_SKIP | CTLFLAG_MPSAFE,
168 0, 0, sysctl_tcp_hc_list, "A",
169 "List of all hostcache entries");
170
171 SYSCTL_PROC(_net_inet_tcp_hostcache, OID_AUTO, histo,
172 CTLTYPE_STRING | CTLFLAG_RD | CTLFLAG_SKIP | CTLFLAG_MPSAFE,
173 0, 0, sysctl_tcp_hc_histo, "A",
174 "Print a histogram of hostcache hashbucket utilization");
175
176 SYSCTL_PROC(_net_inet_tcp_hostcache, OID_AUTO, purgenow,
177 CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_MPSAFE,
178 NULL, 0, sysctl_tcp_hc_purgenow, "I",
179 "Immediately purge all entries");
180
181 static MALLOC_DEFINE(M_HOSTCACHE, "hostcache", "TCP hostcache");
182
183 /* Use jenkins_hash32(), as in other parts of the tcp stack */
184 #define HOSTCACHE_HASH(ip) \
185 (jenkins_hash32((uint32_t *)(ip), 1, V_tcp_hostcache.hashsalt) & \
186 V_tcp_hostcache.hashmask)
187
188 #define HOSTCACHE_HASH6(ip6) \
189 (jenkins_hash32((uint32_t *)&((ip6)->s6_addr32[0]), 4, \
190 V_tcp_hostcache.hashsalt) & \
191 V_tcp_hostcache.hashmask)
192
193 #define THC_LOCK(lp) mtx_lock(lp)
194 #define THC_UNLOCK(lp) mtx_unlock(lp)
195
196 void
tcp_hc_init(void)197 tcp_hc_init(void)
198 {
199 u_int cache_limit;
200 int i;
201
202 /*
203 * Initialize hostcache structures.
204 */
205 atomic_store_int(&V_tcp_hostcache.cache_count, 0);
206 V_tcp_hostcache.hashsize = TCP_HOSTCACHE_HASHSIZE;
207 V_tcp_hostcache.bucket_limit = TCP_HOSTCACHE_BUCKETLIMIT;
208 V_tcp_hostcache.expire = TCP_HOSTCACHE_EXPIRE;
209 V_tcp_hostcache.prune = TCP_HOSTCACHE_PRUNE;
210 V_tcp_hostcache.hashsalt = arc4random();
211
212 TUNABLE_INT_FETCH("net.inet.tcp.hostcache.hashsize",
213 &V_tcp_hostcache.hashsize);
214 if (!powerof2(V_tcp_hostcache.hashsize)) {
215 printf("WARNING: hostcache hash size is not a power of 2.\n");
216 V_tcp_hostcache.hashsize = TCP_HOSTCACHE_HASHSIZE; /* default */
217 }
218 V_tcp_hostcache.hashmask = V_tcp_hostcache.hashsize - 1;
219
220 TUNABLE_INT_FETCH("net.inet.tcp.hostcache.bucketlimit",
221 &V_tcp_hostcache.bucket_limit);
222
223 cache_limit = V_tcp_hostcache.hashsize * V_tcp_hostcache.bucket_limit;
224 V_tcp_hostcache.cache_limit = cache_limit;
225 TUNABLE_INT_FETCH("net.inet.tcp.hostcache.cachelimit",
226 &V_tcp_hostcache.cache_limit);
227 if (V_tcp_hostcache.cache_limit > cache_limit)
228 V_tcp_hostcache.cache_limit = cache_limit;
229
230 /*
231 * Allocate the hash table.
232 */
233 V_tcp_hostcache.hashbase = (struct hc_head *)
234 malloc(V_tcp_hostcache.hashsize * sizeof(struct hc_head),
235 M_HOSTCACHE, M_WAITOK | M_ZERO);
236
237 /*
238 * Initialize the hash buckets.
239 */
240 for (i = 0; i < V_tcp_hostcache.hashsize; i++) {
241 TAILQ_INIT(&V_tcp_hostcache.hashbase[i].hch_bucket);
242 V_tcp_hostcache.hashbase[i].hch_length = 0;
243 mtx_init(&V_tcp_hostcache.hashbase[i].hch_mtx, "tcp_hc_entry",
244 NULL, MTX_DEF);
245 }
246
247 /*
248 * Allocate the hostcache entries.
249 */
250 V_tcp_hostcache.zone =
251 uma_zcreate("hostcache", sizeof(struct hc_metrics),
252 NULL, NULL, NULL, NULL, UMA_ALIGN_PTR, 0);
253 uma_zone_set_max(V_tcp_hostcache.zone, V_tcp_hostcache.cache_limit);
254
255 /*
256 * Set up periodic cache cleanup.
257 */
258 callout_init(&V_tcp_hc_callout, 1);
259 callout_reset(&V_tcp_hc_callout, V_tcp_hostcache.prune * hz,
260 tcp_hc_purge, curvnet);
261 }
262
263 #ifdef VIMAGE
264 void
tcp_hc_destroy(void)265 tcp_hc_destroy(void)
266 {
267 int i;
268
269 callout_drain(&V_tcp_hc_callout);
270
271 /* Purge all hc entries. */
272 tcp_hc_purge_internal(1);
273
274 /* Free the uma zone and the allocated hash table. */
275 uma_zdestroy(V_tcp_hostcache.zone);
276
277 for (i = 0; i < V_tcp_hostcache.hashsize; i++)
278 mtx_destroy(&V_tcp_hostcache.hashbase[i].hch_mtx);
279 free(V_tcp_hostcache.hashbase, M_HOSTCACHE);
280 }
281 #endif
282
283 /*
284 * Internal function: look up an entry in the hostcache or return NULL.
285 *
286 * If an entry has been returned, the caller becomes responsible for
287 * unlocking the bucket row after he is done reading/modifying the entry.
288 */
289 static struct hc_metrics *
tcp_hc_lookup(struct in_conninfo * inc)290 tcp_hc_lookup(struct in_conninfo *inc)
291 {
292 int hash;
293 struct hc_head *hc_head;
294 struct hc_metrics *hc_entry;
295
296 if (!V_tcp_use_hostcache)
297 return NULL;
298
299 KASSERT(inc != NULL, ("tcp_hc_lookup with NULL in_conninfo pointer"));
300
301 /*
302 * Hash the foreign ip address.
303 */
304 if (inc->inc_flags & INC_ISIPV6)
305 hash = HOSTCACHE_HASH6(&inc->inc6_faddr);
306 else
307 hash = HOSTCACHE_HASH(&inc->inc_faddr);
308
309 hc_head = &V_tcp_hostcache.hashbase[hash];
310
311 /*
312 * Acquire lock for this bucket row; we release the lock if we don't
313 * find an entry, otherwise the caller has to unlock after he is
314 * done.
315 */
316 THC_LOCK(&hc_head->hch_mtx);
317
318 /*
319 * Iterate through entries in bucket row looking for a match.
320 */
321 TAILQ_FOREACH(hc_entry, &hc_head->hch_bucket, rmx_q) {
322 if (inc->inc_flags & INC_ISIPV6) {
323 /* XXX: check ip6_zoneid */
324 if (memcmp(&inc->inc6_faddr, &hc_entry->ip6,
325 sizeof(inc->inc6_faddr)) == 0)
326 return hc_entry;
327 } else {
328 if (memcmp(&inc->inc_faddr, &hc_entry->ip4,
329 sizeof(inc->inc_faddr)) == 0)
330 return hc_entry;
331 }
332 }
333
334 /*
335 * We were unsuccessful and didn't find anything.
336 */
337 THC_UNLOCK(&hc_head->hch_mtx);
338 return NULL;
339 }
340
341 /*
342 * Internal function: insert an entry into the hostcache or return NULL if
343 * unable to allocate a new one.
344 *
345 * If an entry has been returned, the caller becomes responsible for
346 * unlocking the bucket row after he is done reading/modifying the entry.
347 */
348 static struct hc_metrics *
tcp_hc_insert(struct in_conninfo * inc)349 tcp_hc_insert(struct in_conninfo *inc)
350 {
351 int hash;
352 struct hc_head *hc_head;
353 struct hc_metrics *hc_entry;
354
355 if (!V_tcp_use_hostcache)
356 return NULL;
357
358 KASSERT(inc != NULL, ("tcp_hc_insert with NULL in_conninfo pointer"));
359
360 /*
361 * Hash the foreign ip address.
362 */
363 if (inc->inc_flags & INC_ISIPV6)
364 hash = HOSTCACHE_HASH6(&inc->inc6_faddr);
365 else
366 hash = HOSTCACHE_HASH(&inc->inc_faddr);
367
368 hc_head = &V_tcp_hostcache.hashbase[hash];
369
370 /*
371 * Acquire lock for this bucket row; we release the lock if we don't
372 * find an entry, otherwise the caller has to unlock after he is
373 * done.
374 */
375 THC_LOCK(&hc_head->hch_mtx);
376
377 /*
378 * If the bucket limit is reached, reuse the least-used element.
379 */
380 if (hc_head->hch_length >= V_tcp_hostcache.bucket_limit ||
381 atomic_load_int(&V_tcp_hostcache.cache_count) >= V_tcp_hostcache.cache_limit) {
382 hc_entry = TAILQ_LAST(&hc_head->hch_bucket, hc_qhead);
383 /*
384 * At first we were dropping the last element, just to
385 * reacquire it in the next two lines again, which isn't very
386 * efficient. Instead just reuse the least used element.
387 * We may drop something that is still "in-use" but we can be
388 * "lossy".
389 * Just give up if this bucket row is empty and we don't have
390 * anything to replace.
391 */
392 if (hc_entry == NULL) {
393 THC_UNLOCK(&hc_head->hch_mtx);
394 return NULL;
395 }
396 TAILQ_REMOVE(&hc_head->hch_bucket, hc_entry, rmx_q);
397 KASSERT(V_tcp_hostcache.hashbase[hash].hch_length > 0 &&
398 V_tcp_hostcache.hashbase[hash].hch_length <=
399 V_tcp_hostcache.bucket_limit,
400 ("tcp_hostcache: bucket length range violated at %u: %u",
401 hash, V_tcp_hostcache.hashbase[hash].hch_length));
402 V_tcp_hostcache.hashbase[hash].hch_length--;
403 atomic_subtract_int(&V_tcp_hostcache.cache_count, 1);
404 TCPSTAT_INC(tcps_hc_bucketoverflow);
405 #if 0
406 uma_zfree(V_tcp_hostcache.zone, hc_entry);
407 #endif
408 } else {
409 /*
410 * Allocate a new entry, or balk if not possible.
411 */
412 hc_entry = uma_zalloc(V_tcp_hostcache.zone, M_NOWAIT);
413 if (hc_entry == NULL) {
414 THC_UNLOCK(&hc_head->hch_mtx);
415 return NULL;
416 }
417 }
418
419 /*
420 * Initialize basic information of hostcache entry.
421 */
422 bzero(hc_entry, sizeof(*hc_entry));
423 if (inc->inc_flags & INC_ISIPV6) {
424 hc_entry->ip6 = inc->inc6_faddr;
425 hc_entry->ip6_zoneid = inc->inc6_zoneid;
426 } else
427 hc_entry->ip4 = inc->inc_faddr;
428 hc_entry->rmx_head = hc_head;
429 hc_entry->rmx_expire = V_tcp_hostcache.expire;
430
431 /*
432 * Put it upfront.
433 */
434 TAILQ_INSERT_HEAD(&hc_head->hch_bucket, hc_entry, rmx_q);
435 V_tcp_hostcache.hashbase[hash].hch_length++;
436 KASSERT(V_tcp_hostcache.hashbase[hash].hch_length <
437 V_tcp_hostcache.bucket_limit,
438 ("tcp_hostcache: bucket length too high at %u: %u",
439 hash, V_tcp_hostcache.hashbase[hash].hch_length));
440 atomic_add_int(&V_tcp_hostcache.cache_count, 1);
441 TCPSTAT_INC(tcps_hc_added);
442
443 return hc_entry;
444 }
445
446 /*
447 * External function: look up an entry in the hostcache and fill out the
448 * supplied TCP metrics structure. Fills in NULL when no entry was found or
449 * a value is not set.
450 */
451 void
tcp_hc_get(struct in_conninfo * inc,struct hc_metrics_lite * hc_metrics_lite)452 tcp_hc_get(struct in_conninfo *inc, struct hc_metrics_lite *hc_metrics_lite)
453 {
454 struct hc_metrics *hc_entry;
455
456 if (!V_tcp_use_hostcache) {
457 bzero(hc_metrics_lite, sizeof(*hc_metrics_lite));
458 return;
459 }
460
461 /*
462 * Find the right bucket.
463 */
464 hc_entry = tcp_hc_lookup(inc);
465
466 /*
467 * If we don't have an existing object.
468 */
469 if (hc_entry == NULL) {
470 bzero(hc_metrics_lite, sizeof(*hc_metrics_lite));
471 return;
472 }
473 hc_entry->rmx_hits++;
474 hc_entry->rmx_expire = V_tcp_hostcache.expire; /* start over again */
475
476 hc_metrics_lite->rmx_mtu = hc_entry->rmx_mtu;
477 hc_metrics_lite->rmx_ssthresh = hc_entry->rmx_ssthresh;
478 hc_metrics_lite->rmx_rtt = hc_entry->rmx_rtt;
479 hc_metrics_lite->rmx_rttvar = hc_entry->rmx_rttvar;
480 hc_metrics_lite->rmx_cwnd = hc_entry->rmx_cwnd;
481 hc_metrics_lite->rmx_sendpipe = hc_entry->rmx_sendpipe;
482 hc_metrics_lite->rmx_recvpipe = hc_entry->rmx_recvpipe;
483
484 /*
485 * Unlock bucket row.
486 */
487 THC_UNLOCK(&hc_entry->rmx_head->hch_mtx);
488 }
489
490 /*
491 * External function: look up an entry in the hostcache and return the
492 * discovered path MTU. Returns 0 if no entry is found or value is not
493 * set.
494 */
495 uint32_t
tcp_hc_getmtu(struct in_conninfo * inc)496 tcp_hc_getmtu(struct in_conninfo *inc)
497 {
498 struct hc_metrics *hc_entry;
499 uint32_t mtu;
500
501 if (!V_tcp_use_hostcache)
502 return 0;
503
504 hc_entry = tcp_hc_lookup(inc);
505 if (hc_entry == NULL) {
506 return 0;
507 }
508 hc_entry->rmx_hits++;
509 hc_entry->rmx_expire = V_tcp_hostcache.expire; /* start over again */
510
511 mtu = hc_entry->rmx_mtu;
512 THC_UNLOCK(&hc_entry->rmx_head->hch_mtx);
513 return mtu;
514 }
515
516 /*
517 * External function: update the MTU value of an entry in the hostcache.
518 * Creates a new entry if none was found.
519 */
520 void
tcp_hc_updatemtu(struct in_conninfo * inc,uint32_t mtu)521 tcp_hc_updatemtu(struct in_conninfo *inc, uint32_t mtu)
522 {
523 struct hc_metrics *hc_entry;
524
525 if (!V_tcp_use_hostcache)
526 return;
527
528 /*
529 * Find the right bucket.
530 */
531 hc_entry = tcp_hc_lookup(inc);
532
533 /*
534 * If we don't have an existing object, try to insert a new one.
535 */
536 if (hc_entry == NULL) {
537 hc_entry = tcp_hc_insert(inc);
538 if (hc_entry == NULL)
539 return;
540 }
541 hc_entry->rmx_updates++;
542 hc_entry->rmx_expire = V_tcp_hostcache.expire; /* start over again */
543
544 hc_entry->rmx_mtu = mtu;
545
546 /*
547 * Put it upfront so we find it faster next time.
548 */
549 TAILQ_REMOVE(&hc_entry->rmx_head->hch_bucket, hc_entry, rmx_q);
550 TAILQ_INSERT_HEAD(&hc_entry->rmx_head->hch_bucket, hc_entry, rmx_q);
551
552 /*
553 * Unlock bucket row.
554 */
555 THC_UNLOCK(&hc_entry->rmx_head->hch_mtx);
556 }
557
558 /*
559 * External function: update the TCP metrics of an entry in the hostcache.
560 * Creates a new entry if none was found.
561 */
562 void
tcp_hc_update(struct in_conninfo * inc,struct hc_metrics_lite * hcml)563 tcp_hc_update(struct in_conninfo *inc, struct hc_metrics_lite *hcml)
564 {
565 struct hc_metrics *hc_entry;
566
567 if (!V_tcp_use_hostcache)
568 return;
569
570 hc_entry = tcp_hc_lookup(inc);
571 if (hc_entry == NULL) {
572 hc_entry = tcp_hc_insert(inc);
573 if (hc_entry == NULL)
574 return;
575 }
576 hc_entry->rmx_updates++;
577 hc_entry->rmx_expire = V_tcp_hostcache.expire; /* start over again */
578
579 if (hcml->rmx_rtt != 0) {
580 if (hc_entry->rmx_rtt == 0)
581 hc_entry->rmx_rtt = hcml->rmx_rtt;
582 else
583 hc_entry->rmx_rtt = ((uint64_t)hc_entry->rmx_rtt +
584 (uint64_t)hcml->rmx_rtt) / 2;
585 TCPSTAT_INC(tcps_cachedrtt);
586 }
587 if (hcml->rmx_rttvar != 0) {
588 if (hc_entry->rmx_rttvar == 0)
589 hc_entry->rmx_rttvar = hcml->rmx_rttvar;
590 else
591 hc_entry->rmx_rttvar = ((uint64_t)hc_entry->rmx_rttvar +
592 (uint64_t)hcml->rmx_rttvar) / 2;
593 TCPSTAT_INC(tcps_cachedrttvar);
594 }
595 if (hcml->rmx_ssthresh != 0) {
596 if (hc_entry->rmx_ssthresh == 0)
597 hc_entry->rmx_ssthresh = hcml->rmx_ssthresh;
598 else
599 hc_entry->rmx_ssthresh =
600 (hc_entry->rmx_ssthresh + hcml->rmx_ssthresh) / 2;
601 TCPSTAT_INC(tcps_cachedssthresh);
602 }
603 if (hcml->rmx_cwnd != 0) {
604 if (hc_entry->rmx_cwnd == 0)
605 hc_entry->rmx_cwnd = hcml->rmx_cwnd;
606 else
607 hc_entry->rmx_cwnd = ((uint64_t)hc_entry->rmx_cwnd +
608 (uint64_t)hcml->rmx_cwnd) / 2;
609 /* TCPSTAT_INC(tcps_cachedcwnd); */
610 }
611 if (hcml->rmx_sendpipe != 0) {
612 if (hc_entry->rmx_sendpipe == 0)
613 hc_entry->rmx_sendpipe = hcml->rmx_sendpipe;
614 else
615 hc_entry->rmx_sendpipe =
616 ((uint64_t)hc_entry->rmx_sendpipe +
617 (uint64_t)hcml->rmx_sendpipe) /2;
618 /* TCPSTAT_INC(tcps_cachedsendpipe); */
619 }
620 if (hcml->rmx_recvpipe != 0) {
621 if (hc_entry->rmx_recvpipe == 0)
622 hc_entry->rmx_recvpipe = hcml->rmx_recvpipe;
623 else
624 hc_entry->rmx_recvpipe =
625 ((uint64_t)hc_entry->rmx_recvpipe +
626 (uint64_t)hcml->rmx_recvpipe) /2;
627 /* TCPSTAT_INC(tcps_cachedrecvpipe); */
628 }
629
630 TAILQ_REMOVE(&hc_entry->rmx_head->hch_bucket, hc_entry, rmx_q);
631 TAILQ_INSERT_HEAD(&hc_entry->rmx_head->hch_bucket, hc_entry, rmx_q);
632 THC_UNLOCK(&hc_entry->rmx_head->hch_mtx);
633 }
634
635 /*
636 * Sysctl function: prints the list and values of all hostcache entries in
637 * unsorted order.
638 */
639 static int
sysctl_tcp_hc_list(SYSCTL_HANDLER_ARGS)640 sysctl_tcp_hc_list(SYSCTL_HANDLER_ARGS)
641 {
642 const int linesize = 128;
643 struct sbuf sb;
644 int i, error, len;
645 struct hc_metrics *hc_entry;
646 char ip4buf[INET_ADDRSTRLEN];
647 #ifdef INET6
648 char ip6buf[INET6_ADDRSTRLEN];
649 #endif
650
651 if (jailed_without_vnet(curthread->td_ucred) != 0)
652 return (EPERM);
653
654 /* Optimize Buffer length query by sbin/sysctl */
655 if (req->oldptr == NULL) {
656 len = (atomic_load_int(&V_tcp_hostcache.cache_count) + 1) *
657 linesize;
658 return (SYSCTL_OUT(req, NULL, len));
659 }
660
661 error = sysctl_wire_old_buffer(req, 0);
662 if (error != 0) {
663 return(error);
664 }
665
666 /* Use a buffer sized for one full bucket */
667 sbuf_new_for_sysctl(&sb, NULL, V_tcp_hostcache.bucket_limit *
668 linesize, req);
669
670 sbuf_printf(&sb,
671 "\nIP address MTU SSTRESH RTT RTTVAR "
672 " CWND SENDPIPE RECVPIPE HITS UPD EXP\n");
673 sbuf_drain(&sb);
674
675 #define msec(u) (((u) + 500) / 1000)
676 for (i = 0; i < V_tcp_hostcache.hashsize; i++) {
677 THC_LOCK(&V_tcp_hostcache.hashbase[i].hch_mtx);
678 TAILQ_FOREACH(hc_entry, &V_tcp_hostcache.hashbase[i].hch_bucket,
679 rmx_q) {
680 sbuf_printf(&sb,
681 "%-15s %5u %8u %6lums %6lums %8u %8u %8u %4lu "
682 "%4lu %4i\n",
683 hc_entry->ip4.s_addr ?
684 inet_ntoa_r(hc_entry->ip4, ip4buf) :
685 #ifdef INET6
686 ip6_sprintf(ip6buf, &hc_entry->ip6),
687 #else
688 "IPv6?",
689 #endif
690 hc_entry->rmx_mtu,
691 hc_entry->rmx_ssthresh,
692 msec((u_long)hc_entry->rmx_rtt *
693 (RTM_RTTUNIT / (hz * TCP_RTT_SCALE))),
694 msec((u_long)hc_entry->rmx_rttvar *
695 (RTM_RTTUNIT / (hz * TCP_RTTVAR_SCALE))),
696 hc_entry->rmx_cwnd,
697 hc_entry->rmx_sendpipe,
698 hc_entry->rmx_recvpipe,
699 hc_entry->rmx_hits,
700 hc_entry->rmx_updates,
701 hc_entry->rmx_expire);
702 }
703 THC_UNLOCK(&V_tcp_hostcache.hashbase[i].hch_mtx);
704 sbuf_drain(&sb);
705 }
706 #undef msec
707 error = sbuf_finish(&sb);
708 sbuf_delete(&sb);
709 return(error);
710 }
711
712 /*
713 * Sysctl function: prints a histogram of the hostcache hashbucket
714 * utilization.
715 */
716 static int
sysctl_tcp_hc_histo(SYSCTL_HANDLER_ARGS)717 sysctl_tcp_hc_histo(SYSCTL_HANDLER_ARGS)
718 {
719 const int linesize = 50;
720 struct sbuf sb;
721 int i, error;
722 int *histo;
723 u_int hch_length;
724
725 if (jailed_without_vnet(curthread->td_ucred) != 0)
726 return (EPERM);
727
728 histo = (int *)malloc(sizeof(int) * (V_tcp_hostcache.bucket_limit + 1),
729 M_TEMP, M_NOWAIT|M_ZERO);
730 if (histo == NULL)
731 return(ENOMEM);
732
733 for (i = 0; i < V_tcp_hostcache.hashsize; i++) {
734 hch_length = V_tcp_hostcache.hashbase[i].hch_length;
735 KASSERT(hch_length <= V_tcp_hostcache.bucket_limit,
736 ("tcp_hostcache: bucket limit exceeded at %u: %u",
737 i, hch_length));
738 histo[hch_length]++;
739 }
740
741 /* Use a buffer for 16 lines */
742 sbuf_new_for_sysctl(&sb, NULL, 16 * linesize, req);
743
744 sbuf_printf(&sb, "\nLength\tCount\n");
745 for (i = 0; i <= V_tcp_hostcache.bucket_limit; i++) {
746 sbuf_printf(&sb, "%u\t%u\n", i, histo[i]);
747 }
748 error = sbuf_finish(&sb);
749 sbuf_delete(&sb);
750 free(histo, M_TEMP);
751 return(error);
752 }
753
754 /*
755 * Caller has to make sure the curvnet is set properly.
756 */
757 static void
tcp_hc_purge_internal(int all)758 tcp_hc_purge_internal(int all)
759 {
760 struct hc_metrics *hc_entry, *hc_next;
761 int i;
762
763 for (i = 0; i < V_tcp_hostcache.hashsize; i++) {
764 THC_LOCK(&V_tcp_hostcache.hashbase[i].hch_mtx);
765 TAILQ_FOREACH_SAFE(hc_entry,
766 &V_tcp_hostcache.hashbase[i].hch_bucket, rmx_q, hc_next) {
767 KASSERT(V_tcp_hostcache.hashbase[i].hch_length > 0 &&
768 V_tcp_hostcache.hashbase[i].hch_length <=
769 V_tcp_hostcache.bucket_limit,
770 ("tcp_hostcache: bucket length out of range at %u: %u",
771 i, V_tcp_hostcache.hashbase[i].hch_length));
772 if (all || hc_entry->rmx_expire <= 0) {
773 TAILQ_REMOVE(&V_tcp_hostcache.hashbase[i].hch_bucket,
774 hc_entry, rmx_q);
775 uma_zfree(V_tcp_hostcache.zone, hc_entry);
776 V_tcp_hostcache.hashbase[i].hch_length--;
777 atomic_subtract_int(&V_tcp_hostcache.cache_count, 1);
778 } else
779 hc_entry->rmx_expire -= V_tcp_hostcache.prune;
780 }
781 THC_UNLOCK(&V_tcp_hostcache.hashbase[i].hch_mtx);
782 }
783 }
784
785 /*
786 * Expire and purge (old|all) entries in the tcp_hostcache. Runs
787 * periodically from the callout.
788 */
789 static void
tcp_hc_purge(void * arg)790 tcp_hc_purge(void *arg)
791 {
792 CURVNET_SET((struct vnet *) arg);
793 int all = 0;
794
795 if (V_tcp_hostcache.purgeall) {
796 if (V_tcp_hostcache.purgeall == 2)
797 V_tcp_hostcache.hashsalt = arc4random();
798 all = 1;
799 V_tcp_hostcache.purgeall = 0;
800 }
801
802 tcp_hc_purge_internal(all);
803
804 callout_reset(&V_tcp_hc_callout, V_tcp_hostcache.prune * hz,
805 tcp_hc_purge, arg);
806 CURVNET_RESTORE();
807 }
808
809 /*
810 * Expire and purge all entries in hostcache immediately.
811 */
812 static int
sysctl_tcp_hc_purgenow(SYSCTL_HANDLER_ARGS)813 sysctl_tcp_hc_purgenow(SYSCTL_HANDLER_ARGS)
814 {
815 int error, val;
816
817 val = 0;
818 error = sysctl_handle_int(oidp, &val, 0, req);
819 if (error || !req->newptr)
820 return (error);
821
822 if (val == 2)
823 V_tcp_hostcache.hashsalt = arc4random();
824 tcp_hc_purge_internal(1);
825
826 callout_reset(&V_tcp_hc_callout, V_tcp_hostcache.prune * hz,
827 tcp_hc_purge, curvnet);
828
829 return (0);
830 }
831