1 /*-
2 * SPDX-License-Identifier: BSD-3-Clause
3 *
4 * Copyright (c) 2002 Andre Oppermann, Internet Business Solutions AG
5 * Copyright (c) 2021 Gleb Smirnoff <glebius@FreeBSD.org>
6 * All rights reserved.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in the
15 * documentation and/or other materials provided with the distribution.
16 * 3. The name of the author may not be used to endorse or promote
17 * products derived from this software without specific prior written
18 * permission.
19 *
20 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
23 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
30 * SUCH DAMAGE.
31 */
32
33 /*
34 * The tcp_hostcache moves the tcp-specific cached metrics from the routing
35 * table to a dedicated structure indexed by the remote IP address. It keeps
36 * information on the measured TCP parameters of past TCP sessions to allow
37 * better initial start values to be used with later connections to/from the
38 * same source. Depending on the network parameters (delay, max MTU,
39 * congestion window) between local and remote sites, this can lead to
40 * significant speed-ups for new TCP connections after the first one.
41 *
42 * Due to the tcp_hostcache, all TCP-specific metrics information in the
43 * routing table have been removed. The inpcb no longer keeps a pointer to
44 * the routing entry, and protocol-initiated route cloning has been removed
45 * as well. With these changes, the routing table has gone back to being
46 * more lightwight and only carries information related to packet forwarding.
47 *
48 * tcp_hostcache is designed for multiple concurrent access in SMP
49 * environments and high contention. It is a straight hash. Each bucket row
50 * is protected by its own lock for modification. Readers are protected by
51 * SMR. This puts certain restrictions on writers, e.g. a writer shall only
52 * insert a fully populated entry into a row. Writer can't reuse least used
53 * entry if a hash is full. Value updates for an entry shall be atomic.
54 *
55 * TCP stack(s) communication with tcp_hostcache() is done via KBI functions
56 * tcp_hc_*() and the hc_metrics_lite structure.
57 *
58 * Since tcp_hostcache is only caching information, there are no fatal
59 * consequences if we either can't allocate a new entry or have to drop
60 * an existing entry, or return somewhat stale information.
61 */
62
63 /*
64 * Many thanks to jlemon for basic structure of tcp_syncache which is being
65 * followed here.
66 */
67
68 #include <sys/cdefs.h>
69 #include "opt_inet6.h"
70
71 #include <sys/param.h>
72 #include <sys/systm.h>
73 #include <sys/hash.h>
74 #include <sys/jail.h>
75 #include <sys/kernel.h>
76 #include <sys/lock.h>
77 #include <sys/mutex.h>
78 #include <sys/malloc.h>
79 #include <sys/proc.h>
80 #include <sys/sbuf.h>
81 #include <sys/smr.h>
82 #include <sys/socket.h>
83 #include <sys/sysctl.h>
84
85 #include <net/vnet.h>
86
87 #include <netinet/in.h>
88 #include <netinet/in_pcb.h>
89 #include <netinet/tcp.h>
90 #include <netinet/tcp_var.h>
91
92 #include <vm/uma.h>
93
94 struct hc_head {
95 CK_SLIST_HEAD(hc_qhead, hc_metrics) hch_bucket;
96 u_int hch_length;
97 struct mtx hch_mtx;
98 };
99
100 struct hc_metrics {
101 /* housekeeping */
102 CK_SLIST_ENTRY(hc_metrics) hc_q;
103 struct in_addr ip4; /* IP address */
104 struct in6_addr ip6; /* IP6 address */
105 uint32_t ip6_zoneid; /* IPv6 scope zone id */
106 /* endpoint specific values for tcp */
107 uint32_t hc_mtu; /* MTU for this path */
108 uint32_t hc_ssthresh; /* outbound gateway buffer limit */
109 uint32_t hc_rtt; /* estimated round trip time */
110 uint32_t hc_rttvar; /* estimated rtt variance */
111 uint32_t hc_cwnd; /* congestion window */
112 uint32_t hc_sendpipe; /* outbound delay-bandwidth product */
113 uint32_t hc_recvpipe; /* inbound delay-bandwidth product */
114 /* TCP hostcache internal data */
115 int hc_expire; /* lifetime for object */
116 #ifdef TCP_HC_COUNTERS
117 u_long hc_hits; /* number of hits */
118 u_long hc_updates; /* number of updates */
119 #endif
120 };
121
122 struct tcp_hostcache {
123 struct hc_head *hashbase;
124 uma_zone_t zone;
125 smr_t smr;
126 u_int hashsize;
127 u_int hashmask;
128 u_int hashsalt;
129 u_int bucket_limit;
130 u_int cache_count;
131 u_int cache_limit;
132 int expire;
133 int prune;
134 int purgeall;
135 };
136
137 /* Arbitrary values */
138 #define TCP_HOSTCACHE_HASHSIZE 512
139 #define TCP_HOSTCACHE_BUCKETLIMIT 30
140 #define TCP_HOSTCACHE_EXPIRE 60*60 /* one hour */
141 #define TCP_HOSTCACHE_PRUNE 5*60 /* every 5 minutes */
142
143 VNET_DEFINE_STATIC(struct tcp_hostcache, tcp_hostcache);
144 #define V_tcp_hostcache VNET(tcp_hostcache)
145
146 VNET_DEFINE_STATIC(struct callout, tcp_hc_callout);
147 #define V_tcp_hc_callout VNET(tcp_hc_callout)
148
149 static struct hc_metrics *tcp_hc_lookup(const struct in_conninfo *);
150 static int sysctl_tcp_hc_list(SYSCTL_HANDLER_ARGS);
151 static int sysctl_tcp_hc_histo(SYSCTL_HANDLER_ARGS);
152 static int sysctl_tcp_hc_purgenow(SYSCTL_HANDLER_ARGS);
153 static void tcp_hc_purge_internal(int);
154 static void tcp_hc_purge(void *);
155
156 static SYSCTL_NODE(_net_inet_tcp, OID_AUTO, hostcache,
157 CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
158 "TCP Host cache");
159
160 VNET_DEFINE(int, tcp_use_hostcache) = 1;
161 #define V_tcp_use_hostcache VNET(tcp_use_hostcache)
162 SYSCTL_INT(_net_inet_tcp_hostcache, OID_AUTO, enable, CTLFLAG_VNET | CTLFLAG_RW,
163 &VNET_NAME(tcp_use_hostcache), 0,
164 "Enable the TCP hostcache");
165
166 SYSCTL_UINT(_net_inet_tcp_hostcache, OID_AUTO, cachelimit, CTLFLAG_VNET | CTLFLAG_RDTUN,
167 &VNET_NAME(tcp_hostcache.cache_limit), 0,
168 "Overall entry limit for hostcache");
169
170 SYSCTL_UINT(_net_inet_tcp_hostcache, OID_AUTO, hashsize, CTLFLAG_VNET | CTLFLAG_RDTUN,
171 &VNET_NAME(tcp_hostcache.hashsize), 0,
172 "Size of TCP hostcache hashtable");
173
174 SYSCTL_UINT(_net_inet_tcp_hostcache, OID_AUTO, bucketlimit,
175 CTLFLAG_VNET | CTLFLAG_RDTUN, &VNET_NAME(tcp_hostcache.bucket_limit), 0,
176 "Per-bucket hash limit for hostcache");
177
178 SYSCTL_UINT(_net_inet_tcp_hostcache, OID_AUTO, count, CTLFLAG_VNET | CTLFLAG_RD,
179 &VNET_NAME(tcp_hostcache.cache_count), 0,
180 "Current number of entries in hostcache");
181
182 SYSCTL_INT(_net_inet_tcp_hostcache, OID_AUTO, expire, CTLFLAG_VNET | CTLFLAG_RW,
183 &VNET_NAME(tcp_hostcache.expire), 0,
184 "Expire time of TCP hostcache entries");
185
186 SYSCTL_INT(_net_inet_tcp_hostcache, OID_AUTO, prune, CTLFLAG_VNET | CTLFLAG_RW,
187 &VNET_NAME(tcp_hostcache.prune), 0,
188 "Time between purge runs");
189
190 SYSCTL_INT(_net_inet_tcp_hostcache, OID_AUTO, purge, CTLFLAG_VNET | CTLFLAG_RW,
191 &VNET_NAME(tcp_hostcache.purgeall), 0,
192 "Expire all entries on next purge run");
193
194 SYSCTL_PROC(_net_inet_tcp_hostcache, OID_AUTO, list,
195 CTLTYPE_STRING | CTLFLAG_RD | CTLFLAG_SKIP | CTLFLAG_MPSAFE,
196 0, 0, sysctl_tcp_hc_list, "A",
197 "List of all hostcache entries");
198
199 SYSCTL_PROC(_net_inet_tcp_hostcache, OID_AUTO, histo,
200 CTLTYPE_STRING | CTLFLAG_RD | CTLFLAG_SKIP | CTLFLAG_MPSAFE,
201 0, 0, sysctl_tcp_hc_histo, "A",
202 "Print a histogram of hostcache hashbucket utilization");
203
204 SYSCTL_PROC(_net_inet_tcp_hostcache, OID_AUTO, purgenow,
205 CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_MPSAFE,
206 NULL, 0, sysctl_tcp_hc_purgenow, "I",
207 "Immediately purge all entries");
208
209 static MALLOC_DEFINE(M_HOSTCACHE, "hostcache", "TCP hostcache");
210
211 /* Use jenkins_hash32(), as in other parts of the tcp stack */
212 #define HOSTCACHE_HASH(inc) \
213 ((inc)->inc_flags & INC_ISIPV6) ? \
214 (jenkins_hash32((inc)->inc6_faddr.s6_addr32, 4, \
215 V_tcp_hostcache.hashsalt) & V_tcp_hostcache.hashmask) \
216 : \
217 (jenkins_hash32(&(inc)->inc_faddr.s_addr, 1, \
218 V_tcp_hostcache.hashsalt) & V_tcp_hostcache.hashmask)
219
220 #define THC_LOCK(h) mtx_lock(&(h)->hch_mtx)
221 #define THC_UNLOCK(h) mtx_unlock(&(h)->hch_mtx)
222
223 void
tcp_hc_init(void)224 tcp_hc_init(void)
225 {
226 u_int cache_limit;
227 int i;
228
229 /*
230 * Initialize hostcache structures.
231 */
232 atomic_store_int(&V_tcp_hostcache.cache_count, 0);
233 V_tcp_hostcache.hashsize = TCP_HOSTCACHE_HASHSIZE;
234 V_tcp_hostcache.bucket_limit = TCP_HOSTCACHE_BUCKETLIMIT;
235 V_tcp_hostcache.expire = TCP_HOSTCACHE_EXPIRE;
236 V_tcp_hostcache.prune = TCP_HOSTCACHE_PRUNE;
237 V_tcp_hostcache.hashsalt = arc4random();
238
239 TUNABLE_INT_FETCH("net.inet.tcp.hostcache.hashsize",
240 &V_tcp_hostcache.hashsize);
241 if (!powerof2(V_tcp_hostcache.hashsize)) {
242 printf("WARNING: hostcache hash size is not a power of 2.\n");
243 V_tcp_hostcache.hashsize = TCP_HOSTCACHE_HASHSIZE; /* default */
244 }
245 V_tcp_hostcache.hashmask = V_tcp_hostcache.hashsize - 1;
246
247 TUNABLE_INT_FETCH("net.inet.tcp.hostcache.bucketlimit",
248 &V_tcp_hostcache.bucket_limit);
249
250 cache_limit = V_tcp_hostcache.hashsize * V_tcp_hostcache.bucket_limit;
251 V_tcp_hostcache.cache_limit = cache_limit;
252 TUNABLE_INT_FETCH("net.inet.tcp.hostcache.cachelimit",
253 &V_tcp_hostcache.cache_limit);
254 if (V_tcp_hostcache.cache_limit > cache_limit)
255 V_tcp_hostcache.cache_limit = cache_limit;
256
257 /*
258 * Allocate the hash table.
259 */
260 V_tcp_hostcache.hashbase = (struct hc_head *)
261 malloc(V_tcp_hostcache.hashsize * sizeof(struct hc_head),
262 M_HOSTCACHE, M_WAITOK | M_ZERO);
263
264 /*
265 * Initialize the hash buckets.
266 */
267 for (i = 0; i < V_tcp_hostcache.hashsize; i++) {
268 CK_SLIST_INIT(&V_tcp_hostcache.hashbase[i].hch_bucket);
269 V_tcp_hostcache.hashbase[i].hch_length = 0;
270 mtx_init(&V_tcp_hostcache.hashbase[i].hch_mtx, "tcp_hc_entry",
271 NULL, MTX_DEF);
272 }
273
274 /*
275 * Allocate the hostcache entries.
276 */
277 V_tcp_hostcache.zone =
278 uma_zcreate("hostcache", sizeof(struct hc_metrics),
279 NULL, NULL, NULL, NULL, UMA_ALIGN_PTR, UMA_ZONE_SMR);
280 uma_zone_set_max(V_tcp_hostcache.zone, V_tcp_hostcache.cache_limit);
281 V_tcp_hostcache.smr = uma_zone_get_smr(V_tcp_hostcache.zone);
282
283 /*
284 * Set up periodic cache cleanup.
285 */
286 callout_init(&V_tcp_hc_callout, 1);
287 callout_reset(&V_tcp_hc_callout, V_tcp_hostcache.prune * hz,
288 tcp_hc_purge, curvnet);
289 }
290
291 #ifdef VIMAGE
292 void
tcp_hc_destroy(void)293 tcp_hc_destroy(void)
294 {
295 int i;
296
297 callout_drain(&V_tcp_hc_callout);
298
299 /* Purge all hc entries. */
300 tcp_hc_purge_internal(1);
301
302 /* Free the uma zone and the allocated hash table. */
303 uma_zdestroy(V_tcp_hostcache.zone);
304
305 for (i = 0; i < V_tcp_hostcache.hashsize; i++)
306 mtx_destroy(&V_tcp_hostcache.hashbase[i].hch_mtx);
307 free(V_tcp_hostcache.hashbase, M_HOSTCACHE);
308 }
309 #endif
310
311 /*
312 * Internal function: compare cache entry to a connection.
313 */
314 static bool
tcp_hc_cmp(struct hc_metrics * hc_entry,const struct in_conninfo * inc)315 tcp_hc_cmp(struct hc_metrics *hc_entry, const struct in_conninfo *inc)
316 {
317
318 if (inc->inc_flags & INC_ISIPV6) {
319 /* XXX: check ip6_zoneid */
320 if (memcmp(&inc->inc6_faddr, &hc_entry->ip6,
321 sizeof(inc->inc6_faddr)) == 0)
322 return (true);
323 } else {
324 if (memcmp(&inc->inc_faddr, &hc_entry->ip4,
325 sizeof(inc->inc_faddr)) == 0)
326 return (true);
327 }
328
329 return (false);
330 }
331
332 /*
333 * Internal function: look up an entry in the hostcache for read.
334 * On success returns in SMR section.
335 */
336 static struct hc_metrics *
tcp_hc_lookup(const struct in_conninfo * inc)337 tcp_hc_lookup(const struct in_conninfo *inc)
338 {
339 struct hc_head *hc_head;
340 struct hc_metrics *hc_entry;
341
342 KASSERT(inc != NULL, ("%s: NULL in_conninfo", __func__));
343
344 hc_head = &V_tcp_hostcache.hashbase[HOSTCACHE_HASH(inc)];
345
346 /*
347 * Iterate through entries in bucket row looking for a match.
348 */
349 smr_enter(V_tcp_hostcache.smr);
350 CK_SLIST_FOREACH(hc_entry, &hc_head->hch_bucket, hc_q)
351 if (tcp_hc_cmp(hc_entry, inc))
352 break;
353
354 if (hc_entry != NULL) {
355 if (atomic_load_int(&hc_entry->hc_expire) !=
356 V_tcp_hostcache.expire)
357 atomic_store_int(&hc_entry->hc_expire,
358 V_tcp_hostcache.expire);
359 #ifdef TCP_HC_COUNTERS
360 hc_entry->hc_hits++;
361 #endif
362 } else
363 smr_exit(V_tcp_hostcache.smr);
364
365 return (hc_entry);
366 }
367
368 /*
369 * External function: look up an entry in the hostcache and fill out the
370 * supplied TCP metrics structure. Fills in NULL when no entry was found or
371 * a value is not set.
372 */
373 void
tcp_hc_get(const struct in_conninfo * inc,struct hc_metrics_lite * hc_metrics_lite)374 tcp_hc_get(const struct in_conninfo *inc,
375 struct hc_metrics_lite *hc_metrics_lite)
376 {
377 struct hc_metrics *hc_entry;
378
379 if (!V_tcp_use_hostcache) {
380 bzero(hc_metrics_lite, sizeof(*hc_metrics_lite));
381 return;
382 }
383
384 /*
385 * Find the right bucket.
386 */
387 hc_entry = tcp_hc_lookup(inc);
388
389 /*
390 * If we don't have an existing object.
391 */
392 if (hc_entry == NULL) {
393 bzero(hc_metrics_lite, sizeof(*hc_metrics_lite));
394 return;
395 }
396
397 hc_metrics_lite->hc_mtu = atomic_load_32(&hc_entry->hc_mtu);
398 hc_metrics_lite->hc_ssthresh = atomic_load_32(&hc_entry->hc_ssthresh);
399 hc_metrics_lite->hc_rtt = atomic_load_32(&hc_entry->hc_rtt);
400 hc_metrics_lite->hc_rttvar = atomic_load_32(&hc_entry->hc_rttvar);
401 hc_metrics_lite->hc_cwnd = atomic_load_32(&hc_entry->hc_cwnd);
402 hc_metrics_lite->hc_sendpipe = atomic_load_32(&hc_entry->hc_sendpipe);
403 hc_metrics_lite->hc_recvpipe = atomic_load_32(&hc_entry->hc_recvpipe);
404
405 smr_exit(V_tcp_hostcache.smr);
406 }
407
408 /*
409 * External function: look up an entry in the hostcache and return the
410 * discovered path MTU. Returns 0 if no entry is found or value is not
411 * set.
412 */
413 uint32_t
tcp_hc_getmtu(const struct in_conninfo * inc)414 tcp_hc_getmtu(const struct in_conninfo *inc)
415 {
416 struct hc_metrics *hc_entry;
417 uint32_t mtu;
418
419 if (!V_tcp_use_hostcache)
420 return (0);
421
422 hc_entry = tcp_hc_lookup(inc);
423 if (hc_entry == NULL) {
424 return (0);
425 }
426
427 mtu = atomic_load_32(&hc_entry->hc_mtu);
428 smr_exit(V_tcp_hostcache.smr);
429
430 return (mtu);
431 }
432
433 /*
434 * External function: update the MTU value of an entry in the hostcache.
435 * Creates a new entry if none was found.
436 */
437 void
tcp_hc_updatemtu(const struct in_conninfo * inc,uint32_t mtu)438 tcp_hc_updatemtu(const struct in_conninfo *inc, uint32_t mtu)
439 {
440 struct hc_metrics_lite hcml = { .hc_mtu = mtu };
441
442 return (tcp_hc_update(inc, &hcml));
443 }
444
445 /*
446 * External function: update the TCP metrics of an entry in the hostcache.
447 * Creates a new entry if none was found.
448 */
449 void
tcp_hc_update(const struct in_conninfo * inc,struct hc_metrics_lite * hcml)450 tcp_hc_update(const struct in_conninfo *inc, struct hc_metrics_lite *hcml)
451 {
452 struct hc_head *hc_head;
453 struct hc_metrics *hc_entry, *hc_prev;
454 uint32_t v;
455 bool new;
456
457 if (!V_tcp_use_hostcache)
458 return;
459
460 hc_head = &V_tcp_hostcache.hashbase[HOSTCACHE_HASH(inc)];
461 hc_prev = NULL;
462
463 THC_LOCK(hc_head);
464 CK_SLIST_FOREACH(hc_entry, &hc_head->hch_bucket, hc_q) {
465 if (tcp_hc_cmp(hc_entry, inc))
466 break;
467 if (CK_SLIST_NEXT(hc_entry, hc_q) != NULL)
468 hc_prev = hc_entry;
469 }
470
471 if (hc_entry != NULL) {
472 if (atomic_load_int(&hc_entry->hc_expire) !=
473 V_tcp_hostcache.expire)
474 atomic_store_int(&hc_entry->hc_expire,
475 V_tcp_hostcache.expire);
476 #ifdef TCP_HC_COUNTERS
477 hc_entry->hc_updates++;
478 #endif
479 new = false;
480 } else {
481 /*
482 * Try to allocate a new entry. If the bucket limit is
483 * reached, delete the least-used element, located at the end
484 * of the CK_SLIST. During lookup we saved the pointer to
485 * the second to last element, in case if list has at least 2
486 * elements. This will allow to delete last element without
487 * extra traversal.
488 *
489 * Give up if the row is empty.
490 */
491 if (hc_head->hch_length >= V_tcp_hostcache.bucket_limit ||
492 atomic_load_int(&V_tcp_hostcache.cache_count) >=
493 V_tcp_hostcache.cache_limit) {
494 if (hc_prev != NULL) {
495 hc_entry = CK_SLIST_NEXT(hc_prev, hc_q);
496 KASSERT(CK_SLIST_NEXT(hc_entry, hc_q) == NULL,
497 ("%s: %p is not one to last",
498 __func__, hc_prev));
499 CK_SLIST_REMOVE_AFTER(hc_prev, hc_q);
500 } else if ((hc_entry =
501 CK_SLIST_FIRST(&hc_head->hch_bucket)) != NULL) {
502 KASSERT(CK_SLIST_NEXT(hc_entry, hc_q) == NULL,
503 ("%s: %p is not the only element",
504 __func__, hc_entry));
505 CK_SLIST_REMOVE_HEAD(&hc_head->hch_bucket,
506 hc_q);
507 } else {
508 THC_UNLOCK(hc_head);
509 return;
510 }
511 KASSERT(hc_head->hch_length > 0 &&
512 hc_head->hch_length <= V_tcp_hostcache.bucket_limit,
513 ("tcp_hostcache: bucket length violated at %p",
514 hc_head));
515 hc_head->hch_length--;
516 atomic_subtract_int(&V_tcp_hostcache.cache_count, 1);
517 TCPSTAT_INC(tcps_hc_bucketoverflow);
518 uma_zfree_smr(V_tcp_hostcache.zone, hc_entry);
519 }
520
521 /*
522 * Allocate a new entry, or balk if not possible.
523 */
524 hc_entry = uma_zalloc_smr(V_tcp_hostcache.zone, M_NOWAIT);
525 if (hc_entry == NULL) {
526 THC_UNLOCK(hc_head);
527 return;
528 }
529
530 /*
531 * Initialize basic information of hostcache entry.
532 */
533 bzero(hc_entry, sizeof(*hc_entry));
534 if (inc->inc_flags & INC_ISIPV6) {
535 hc_entry->ip6 = inc->inc6_faddr;
536 hc_entry->ip6_zoneid = inc->inc6_zoneid;
537 } else
538 hc_entry->ip4 = inc->inc_faddr;
539 hc_entry->hc_expire = V_tcp_hostcache.expire;
540 new = true;
541 }
542
543 /*
544 * Fill in data. Use atomics, since an existing entry is
545 * accessible by readers in SMR section.
546 */
547 if (hcml->hc_mtu != 0) {
548 atomic_store_32(&hc_entry->hc_mtu, hcml->hc_mtu);
549 }
550 if (hcml->hc_rtt != 0) {
551 if (hc_entry->hc_rtt == 0)
552 v = hcml->hc_rtt;
553 else
554 v = ((uint64_t)hc_entry->hc_rtt +
555 (uint64_t)hcml->hc_rtt) / 2;
556 atomic_store_32(&hc_entry->hc_rtt, v);
557 TCPSTAT_INC(tcps_cachedrtt);
558 }
559 if (hcml->hc_rttvar != 0) {
560 if (hc_entry->hc_rttvar == 0)
561 v = hcml->hc_rttvar;
562 else
563 v = ((uint64_t)hc_entry->hc_rttvar +
564 (uint64_t)hcml->hc_rttvar) / 2;
565 atomic_store_32(&hc_entry->hc_rttvar, v);
566 TCPSTAT_INC(tcps_cachedrttvar);
567 }
568 if (hcml->hc_ssthresh != 0) {
569 if (hc_entry->hc_ssthresh == 0)
570 v = hcml->hc_ssthresh;
571 else
572 v = (hc_entry->hc_ssthresh + hcml->hc_ssthresh) / 2;
573 atomic_store_32(&hc_entry->hc_ssthresh, v);
574 TCPSTAT_INC(tcps_cachedssthresh);
575 }
576 if (hcml->hc_cwnd != 0) {
577 if (hc_entry->hc_cwnd == 0)
578 v = hcml->hc_cwnd;
579 else
580 v = ((uint64_t)hc_entry->hc_cwnd +
581 (uint64_t)hcml->hc_cwnd) / 2;
582 atomic_store_32(&hc_entry->hc_cwnd, v);
583 /* TCPSTAT_INC(tcps_cachedcwnd); */
584 }
585 if (hcml->hc_sendpipe != 0) {
586 if (hc_entry->hc_sendpipe == 0)
587 v = hcml->hc_sendpipe;
588 else
589 v = ((uint64_t)hc_entry->hc_sendpipe +
590 (uint64_t)hcml->hc_sendpipe) /2;
591 atomic_store_32(&hc_entry->hc_sendpipe, v);
592 /* TCPSTAT_INC(tcps_cachedsendpipe); */
593 }
594 if (hcml->hc_recvpipe != 0) {
595 if (hc_entry->hc_recvpipe == 0)
596 v = hcml->hc_recvpipe;
597 else
598 v = ((uint64_t)hc_entry->hc_recvpipe +
599 (uint64_t)hcml->hc_recvpipe) /2;
600 atomic_store_32(&hc_entry->hc_recvpipe, v);
601 /* TCPSTAT_INC(tcps_cachedrecvpipe); */
602 }
603
604 /*
605 * Put it upfront.
606 */
607 if (new) {
608 CK_SLIST_INSERT_HEAD(&hc_head->hch_bucket, hc_entry, hc_q);
609 hc_head->hch_length++;
610 KASSERT(hc_head->hch_length <= V_tcp_hostcache.bucket_limit,
611 ("tcp_hostcache: bucket length too high at %p", hc_head));
612 atomic_add_int(&V_tcp_hostcache.cache_count, 1);
613 TCPSTAT_INC(tcps_hc_added);
614 } else if (hc_entry != CK_SLIST_FIRST(&hc_head->hch_bucket)) {
615 KASSERT(CK_SLIST_NEXT(hc_prev, hc_q) == hc_entry,
616 ("%s: %p next is not %p", __func__, hc_prev, hc_entry));
617 CK_SLIST_REMOVE_AFTER(hc_prev, hc_q);
618 CK_SLIST_INSERT_HEAD(&hc_head->hch_bucket, hc_entry, hc_q);
619 }
620 THC_UNLOCK(hc_head);
621 }
622
623 /*
624 * Sysctl function: prints the list and values of all hostcache entries in
625 * unsorted order.
626 */
627 static int
sysctl_tcp_hc_list(SYSCTL_HANDLER_ARGS)628 sysctl_tcp_hc_list(SYSCTL_HANDLER_ARGS)
629 {
630 const int linesize = 128;
631 struct sbuf sb;
632 int i, error, len;
633 struct hc_metrics *hc_entry;
634 char ip4buf[INET_ADDRSTRLEN];
635 #ifdef INET6
636 char ip6buf[INET6_ADDRSTRLEN];
637 #endif
638
639 if (jailed_without_vnet(curthread->td_ucred) != 0)
640 return (EPERM);
641
642 /* Optimize Buffer length query by sbin/sysctl */
643 if (req->oldptr == NULL) {
644 len = (atomic_load_int(&V_tcp_hostcache.cache_count) + 1) *
645 linesize;
646 return (SYSCTL_OUT(req, NULL, len));
647 }
648
649 error = sysctl_wire_old_buffer(req, 0);
650 if (error != 0) {
651 return(error);
652 }
653
654 /* Use a buffer sized for one full bucket */
655 sbuf_new_for_sysctl(&sb, NULL, V_tcp_hostcache.bucket_limit *
656 linesize, req);
657
658 sbuf_printf(&sb,
659 "\nIP address MTU SSTRESH RTT RTTVAR "
660 " CWND SENDPIPE RECVPIPE "
661 #ifdef TCP_HC_COUNTERS
662 "HITS UPD "
663 #endif
664 "EXP\n");
665 sbuf_drain(&sb);
666
667 #define msec(u) (((u) + 500) / 1000)
668 for (i = 0; i < V_tcp_hostcache.hashsize; i++) {
669 THC_LOCK(&V_tcp_hostcache.hashbase[i]);
670 CK_SLIST_FOREACH(hc_entry,
671 &V_tcp_hostcache.hashbase[i].hch_bucket, hc_q) {
672 sbuf_printf(&sb,
673 "%-15s %5u %8u %6lums %6lums %8u %8u %8u "
674 #ifdef TCP_HC_COUNTERS
675 "%4lu %4lu "
676 #endif
677 "%4i\n",
678 hc_entry->ip4.s_addr ?
679 inet_ntoa_r(hc_entry->ip4, ip4buf) :
680 #ifdef INET6
681 ip6_sprintf(ip6buf, &hc_entry->ip6),
682 #else
683 "IPv6?",
684 #endif
685 hc_entry->hc_mtu,
686 hc_entry->hc_ssthresh,
687 msec((u_long)hc_entry->hc_rtt *
688 (RTM_RTTUNIT / (hz * TCP_RTT_SCALE))),
689 msec((u_long)hc_entry->hc_rttvar *
690 (RTM_RTTUNIT / (hz * TCP_RTTVAR_SCALE))),
691 hc_entry->hc_cwnd,
692 hc_entry->hc_sendpipe,
693 hc_entry->hc_recvpipe,
694 #ifdef TCP_HC_COUNTERS
695 hc_entry->hc_hits,
696 hc_entry->hc_updates,
697 #endif
698 hc_entry->hc_expire);
699 }
700 THC_UNLOCK(&V_tcp_hostcache.hashbase[i]);
701 sbuf_drain(&sb);
702 }
703 #undef msec
704 error = sbuf_finish(&sb);
705 sbuf_delete(&sb);
706 return(error);
707 }
708
709 /*
710 * Sysctl function: prints a histogram of the hostcache hashbucket
711 * utilization.
712 */
713 static int
sysctl_tcp_hc_histo(SYSCTL_HANDLER_ARGS)714 sysctl_tcp_hc_histo(SYSCTL_HANDLER_ARGS)
715 {
716 const int linesize = 50;
717 struct sbuf sb;
718 int i, error;
719 int *histo;
720 u_int hch_length;
721
722 if (jailed_without_vnet(curthread->td_ucred) != 0)
723 return (EPERM);
724
725 histo = (int *)malloc(sizeof(int) * (V_tcp_hostcache.bucket_limit + 1),
726 M_TEMP, M_NOWAIT|M_ZERO);
727 if (histo == NULL)
728 return(ENOMEM);
729
730 for (i = 0; i < V_tcp_hostcache.hashsize; i++) {
731 hch_length = V_tcp_hostcache.hashbase[i].hch_length;
732 KASSERT(hch_length <= V_tcp_hostcache.bucket_limit,
733 ("tcp_hostcache: bucket limit exceeded at %u: %u",
734 i, hch_length));
735 histo[hch_length]++;
736 }
737
738 /* Use a buffer for 16 lines */
739 sbuf_new_for_sysctl(&sb, NULL, 16 * linesize, req);
740
741 sbuf_printf(&sb, "\nLength\tCount\n");
742 for (i = 0; i <= V_tcp_hostcache.bucket_limit; i++) {
743 sbuf_printf(&sb, "%u\t%u\n", i, histo[i]);
744 }
745 error = sbuf_finish(&sb);
746 sbuf_delete(&sb);
747 free(histo, M_TEMP);
748 return(error);
749 }
750
751 /*
752 * Caller has to make sure the curvnet is set properly.
753 */
754 static void
tcp_hc_purge_internal(int all)755 tcp_hc_purge_internal(int all)
756 {
757 struct hc_head *head;
758 struct hc_metrics *hc_entry, *hc_next, *hc_prev;
759 int i;
760
761 for (i = 0; i < V_tcp_hostcache.hashsize; i++) {
762 head = &V_tcp_hostcache.hashbase[i];
763 hc_prev = NULL;
764 THC_LOCK(head);
765 CK_SLIST_FOREACH_SAFE(hc_entry, &head->hch_bucket, hc_q,
766 hc_next) {
767 KASSERT(head->hch_length > 0 && head->hch_length <=
768 V_tcp_hostcache.bucket_limit, ("tcp_hostcache: "
769 "bucket length out of range at %u: %u", i,
770 head->hch_length));
771 if (all ||
772 atomic_load_int(&hc_entry->hc_expire) <= 0) {
773 if (hc_prev != NULL) {
774 KASSERT(hc_entry ==
775 CK_SLIST_NEXT(hc_prev, hc_q),
776 ("%s: %p is not next to %p",
777 __func__, hc_entry, hc_prev));
778 CK_SLIST_REMOVE_AFTER(hc_prev, hc_q);
779 } else {
780 KASSERT(hc_entry ==
781 CK_SLIST_FIRST(&head->hch_bucket),
782 ("%s: %p is not first",
783 __func__, hc_entry));
784 CK_SLIST_REMOVE_HEAD(&head->hch_bucket,
785 hc_q);
786 }
787 uma_zfree_smr(V_tcp_hostcache.zone, hc_entry);
788 head->hch_length--;
789 atomic_subtract_int(&V_tcp_hostcache.cache_count, 1);
790 } else {
791 atomic_subtract_int(&hc_entry->hc_expire,
792 V_tcp_hostcache.prune);
793 hc_prev = hc_entry;
794 }
795 }
796 THC_UNLOCK(head);
797 }
798 }
799
800 /*
801 * Expire and purge (old|all) entries in the tcp_hostcache. Runs
802 * periodically from the callout.
803 */
804 static void
tcp_hc_purge(void * arg)805 tcp_hc_purge(void *arg)
806 {
807 CURVNET_SET((struct vnet *) arg);
808 int all = 0;
809
810 if (V_tcp_hostcache.purgeall) {
811 if (V_tcp_hostcache.purgeall == 2)
812 V_tcp_hostcache.hashsalt = arc4random();
813 all = 1;
814 V_tcp_hostcache.purgeall = 0;
815 }
816
817 tcp_hc_purge_internal(all);
818
819 callout_reset(&V_tcp_hc_callout, V_tcp_hostcache.prune * hz,
820 tcp_hc_purge, arg);
821 CURVNET_RESTORE();
822 }
823
824 /*
825 * Expire and purge all entries in hostcache immediately.
826 */
827 static int
sysctl_tcp_hc_purgenow(SYSCTL_HANDLER_ARGS)828 sysctl_tcp_hc_purgenow(SYSCTL_HANDLER_ARGS)
829 {
830 int error, val;
831
832 val = 0;
833 error = sysctl_handle_int(oidp, &val, 0, req);
834 if (error || !req->newptr)
835 return (error);
836
837 if (val == 2)
838 V_tcp_hostcache.hashsalt = arc4random();
839 tcp_hc_purge_internal(1);
840
841 callout_reset(&V_tcp_hc_callout, V_tcp_hostcache.prune * hz,
842 tcp_hc_purge, curvnet);
843
844 return (0);
845 }
846