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 * $FreeBSD: releng/6.0/sys/netinet/tcp_hostcache.c 139823 2005-01-07 01:45:51Z imp $
30 */
31
32 /*
33 * The tcp_hostcache moves the tcp specific cached metrics from the routing
34 * table into a dedicated structure indexed by the remote IP address. It
35 * keeps information on the measured tcp parameters of past tcp sessions
36 * to have better initial start values for following connections from the
37 * same source. Depending on the network parameters (delay, bandwidth, max
38 * MTU, congestion window) between local and remote site this can lead to
39 * significant speedups for new tcp connections after the first one.
40 *
41 * Due to this new tcp_hostcache all tcp specific metrics information in
42 * the routing table has been removed. The INPCB no longer keeps a pointer
43 * to the routing entry and protocol initiated route cloning has been
44 * removed as well. With these changes the routing table has gone back
45 * to being more lightwight and only carries information related to packet
46 * forwarding.
47 *
48 * Tcp_hostcache is designed for multiple concurrent access in SMP
49 * environments and high contention. All bucket rows have their own
50 * lock and thus multiple lookups and modifies can be done at the same
51 * time as long as they are in different bucket rows. If a request for
52 * insertion of a new record can't be satisfied it simply returns an
53 * empty structure. Nobody and nothing shall ever point directly to
54 * any entry in tcp_hostcache. All communication is done in an object
55 * oriented way and only funtions of tcp_hostcache will manipulate hostcache
56 * entries. Otherwise we are unable to achieve good behaviour in concurrent
57 * access situations. Since tcp_hostcache is only caching information there
58 * are no fatal consequences if we either can't satisfy any particular request
59 * or have to drop/overwrite an existing entry because of bucket limit
60 * memory constrains.
61 */
62
63 /*
64 * Many thanks to jlemon for basic structure of tcp_syncache which is being
65 * followed here.
66 */
67
68 #include "opt_inet6.h"
69
70 #include <sys/param.h>
71 #include <sys/systm.h>
72 #include <sys/kernel.h>
73 #include <sys/lock.h>
74 #include <sys/mutex.h>
75 #include <sys/malloc.h>
76 #include <sys/socket.h>
77 #include <sys/socketvar.h>
78 #include <sys/sysctl.h>
79
80 #include <net/if.h>
81
82 #include <netinet/in.h>
83 #include <netinet/in_systm.h>
84 #include <netinet/ip.h>
85 #include <netinet/in_var.h>
86 #include <netinet/in_pcb.h>
87 #include <netinet/ip_var.h>
88 #ifdef INET6
89 #include <netinet/ip6.h>
90 #include <netinet6/ip6_var.h>
91 #endif
92 #include <netinet/tcp.h>
93 #include <netinet/tcp_var.h>
94 #ifdef INET6
95 #include <netinet6/tcp6_var.h>
96 #endif
97
98 #include <vm/uma.h>
99
100
101 TAILQ_HEAD(hc_qhead, hc_metrics);
102
103 struct hc_head {
104 struct hc_qhead hch_bucket;
105 u_int hch_length;
106 struct mtx hch_mtx;
107 };
108
109 struct hc_metrics {
110 /* housekeeping */
111 TAILQ_ENTRY(hc_metrics) rmx_q;
112 struct hc_head *rmx_head; /* head of bucket tail queue */
113 struct in_addr ip4; /* IP address */
114 struct in6_addr ip6; /* IP6 address */
115 /* endpoint specific values for tcp */
116 u_long rmx_mtu; /* MTU for this path */
117 u_long rmx_ssthresh; /* outbound gateway buffer limit */
118 u_long rmx_rtt; /* estimated round trip time */
119 u_long rmx_rttvar; /* estimated rtt variance */
120 u_long rmx_bandwidth; /* estimated bandwidth */
121 u_long rmx_cwnd; /* congestion window */
122 u_long rmx_sendpipe; /* outbound delay-bandwidth product */
123 u_long rmx_recvpipe; /* inbound delay-bandwidth product */
124 /* tcp hostcache internal data */
125 int rmx_expire; /* lifetime for object */
126 u_long rmx_hits; /* number of hits */
127 u_long rmx_updates; /* number of updates */
128 };
129
130 /* Arbitrary values */
131 #define TCP_HOSTCACHE_HASHSIZE 512
132 #define TCP_HOSTCACHE_BUCKETLIMIT 30
133 #define TCP_HOSTCACHE_EXPIRE 60*60 /* one hour */
134 #define TCP_HOSTCACHE_PRUNE 5*60 /* every 5 minutes */
135
136 struct tcp_hostcache {
137 struct hc_head *hashbase;
138 uma_zone_t zone;
139 u_int hashsize;
140 u_int hashmask;
141 u_int bucket_limit;
142 u_int cache_count;
143 u_int cache_limit;
144 int expire;
145 int purgeall;
146 };
147 static struct tcp_hostcache tcp_hostcache;
148
149 static struct callout tcp_hc_callout;
150
151 static struct hc_metrics *tcp_hc_lookup(struct in_conninfo *);
152 static struct hc_metrics *tcp_hc_insert(struct in_conninfo *);
153 static int sysctl_tcp_hc_list(SYSCTL_HANDLER_ARGS);
154 static void tcp_hc_purge(void *);
155
156 SYSCTL_NODE(_net_inet_tcp, OID_AUTO, hostcache, CTLFLAG_RW, 0, "TCP Host cache");
157
158 SYSCTL_INT(_net_inet_tcp_hostcache, OID_AUTO, cachelimit, CTLFLAG_RDTUN,
159 &tcp_hostcache.cache_limit, 0, "Overall entry limit for hostcache");
160
161 SYSCTL_INT(_net_inet_tcp_hostcache, OID_AUTO, hashsize, CTLFLAG_RDTUN,
162 &tcp_hostcache.hashsize, 0, "Size of TCP hostcache hashtable");
163
164 SYSCTL_INT(_net_inet_tcp_hostcache, OID_AUTO, bucketlimit, CTLFLAG_RDTUN,
165 &tcp_hostcache.bucket_limit, 0, "Per-bucket hash limit for hostcache");
166
167 SYSCTL_INT(_net_inet_tcp_hostcache, OID_AUTO, count, CTLFLAG_RD,
168 &tcp_hostcache.cache_count, 0, "Current number of entries in hostcache");
169
170 SYSCTL_INT(_net_inet_tcp_hostcache, OID_AUTO, expire, CTLFLAG_RW,
171 &tcp_hostcache.expire, 0, "Expire time of TCP hostcache entries");
172
173 SYSCTL_INT(_net_inet_tcp_hostcache, OID_AUTO, purge, CTLFLAG_RW,
174 &tcp_hostcache.purgeall, 0, "Expire all entires on next purge run");
175
176 SYSCTL_PROC(_net_inet_tcp_hostcache, OID_AUTO, list,
177 CTLTYPE_STRING | CTLFLAG_RD | CTLFLAG_SKIP, 0, 0,
178 sysctl_tcp_hc_list, "A", "List of all hostcache entries");
179
180
181 static MALLOC_DEFINE(M_HOSTCACHE, "hostcache", "TCP hostcache");
182
183 #define HOSTCACHE_HASH(ip) \
184 (((ip)->s_addr ^ ((ip)->s_addr >> 7) ^ ((ip)->s_addr >> 17)) & \
185 tcp_hostcache.hashmask)
186
187 /* XXX: What is the recommended hash to get good entropy for IPv6 addresses? */
188 #define HOSTCACHE_HASH6(ip6) \
189 (((ip6)->s6_addr32[0] ^ \
190 (ip6)->s6_addr32[1] ^ \
191 (ip6)->s6_addr32[2] ^ \
192 (ip6)->s6_addr32[3]) & \
193 tcp_hostcache.hashmask)
194
195 #define THC_LOCK(lp) mtx_lock(lp)
196 #define THC_UNLOCK(lp) mtx_unlock(lp)
197
198 void
199 tcp_hc_init(void)
200 {
201 int i;
202
203 /*
204 * Initialize hostcache structures
205 */
206 tcp_hostcache.cache_count = 0;
207 tcp_hostcache.hashsize = TCP_HOSTCACHE_HASHSIZE;
208 tcp_hostcache.bucket_limit = TCP_HOSTCACHE_BUCKETLIMIT;
209 tcp_hostcache.cache_limit =
210 tcp_hostcache.hashsize * tcp_hostcache.bucket_limit;
211 tcp_hostcache.expire = TCP_HOSTCACHE_EXPIRE;
212
213 TUNABLE_INT_FETCH("net.inet.tcp.hostcache.hashsize",
214 &tcp_hostcache.hashsize);
215 TUNABLE_INT_FETCH("net.inet.tcp.hostcache.cachelimit",
216 &tcp_hostcache.cache_limit);
217 TUNABLE_INT_FETCH("net.inet.tcp.hostcache.bucketlimit",
218 &tcp_hostcache.bucket_limit);
219 if (!powerof2(tcp_hostcache.hashsize)) {
220 printf("WARNING: hostcache hash size is not a power of 2.\n");
221 tcp_hostcache.hashsize = 512; /* safe default */
222 }
223 tcp_hostcache.hashmask = tcp_hostcache.hashsize - 1;
224
225 /*
226 * Allocate the hash table
227 */
228 tcp_hostcache.hashbase = (struct hc_head *)
229 malloc(tcp_hostcache.hashsize * sizeof(struct hc_head),
230 M_HOSTCACHE, M_WAITOK | M_ZERO);
231
232 /*
233 * Initialize the hash buckets
234 */
235 for (i = 0; i < tcp_hostcache.hashsize; i++) {
236 TAILQ_INIT(&tcp_hostcache.hashbase[i].hch_bucket);
237 tcp_hostcache.hashbase[i].hch_length = 0;
238 mtx_init(&tcp_hostcache.hashbase[i].hch_mtx, "tcp_hc_entry",
239 NULL, MTX_DEF);
240 }
241
242 /*
243 * Allocate the hostcache entries.
244 */
245 tcp_hostcache.zone = uma_zcreate("hostcache", sizeof(struct hc_metrics),
246 NULL, NULL, NULL, NULL, UMA_ALIGN_PTR, 0);
247 uma_zone_set_max(tcp_hostcache.zone, tcp_hostcache.cache_limit);
248
249 /*
250 * Set up periodic cache cleanup.
251 */
252 callout_init(&tcp_hc_callout, CALLOUT_MPSAFE);
253 callout_reset(&tcp_hc_callout, TCP_HOSTCACHE_PRUNE * hz, tcp_hc_purge, 0);
254 }
255
256 /*
257 * Internal function: lookup an entry in the hostcache or return NULL.
258 *
259 * If an entry has been returned, the caller becomes responsible for
260 * unlocking the bucket row after he is done reading/modifying the entry.
261 */
262 static struct hc_metrics *
263 tcp_hc_lookup(struct in_conninfo *inc)
264 {
265 int hash;
266 struct hc_head *hc_head;
267 struct hc_metrics *hc_entry;
268
269 KASSERT(inc != NULL, ("tcp_hc_lookup with NULL in_conninfo pointer"));
270
271 /*
272 * Hash the foreign ip address.
273 */
274 if (inc->inc_isipv6)
275 hash = HOSTCACHE_HASH6(&inc->inc6_faddr);
276 else
277 hash = HOSTCACHE_HASH(&inc->inc_faddr);
278
279 hc_head = &tcp_hostcache.hashbase[hash];
280
281 /*
282 * aquire lock for this bucket row
283 * we release the lock if we don't find an entry,
284 * otherwise the caller has to unlock after he is done
285 */
286 THC_LOCK(&hc_head->hch_mtx);
287
288 /*
289 * circle through entries in bucket row looking for a match
290 */
291 TAILQ_FOREACH(hc_entry, &hc_head->hch_bucket, rmx_q) {
292 if (inc->inc_isipv6) {
293 if (memcmp(&inc->inc6_faddr, &hc_entry->ip6,
294 sizeof(inc->inc6_faddr)) == 0)
295 return hc_entry;
296 } else {
297 if (memcmp(&inc->inc_faddr, &hc_entry->ip4,
298 sizeof(inc->inc_faddr)) == 0)
299 return hc_entry;
300 }
301 }
302
303 /*
304 * We were unsuccessful and didn't find anything
305 */
306 THC_UNLOCK(&hc_head->hch_mtx);
307 return NULL;
308 }
309
310 /*
311 * Internal function: insert an entry into the hostcache or return NULL
312 * if unable to allocate a new one.
313 *
314 * If an entry has been returned, the caller becomes responsible for
315 * unlocking the bucket row after he is done reading/modifying the entry.
316 */
317 static struct hc_metrics *
318 tcp_hc_insert(struct in_conninfo *inc)
319 {
320 int hash;
321 struct hc_head *hc_head;
322 struct hc_metrics *hc_entry;
323
324 KASSERT(inc != NULL, ("tcp_hc_insert with NULL in_conninfo pointer"));
325
326 /*
327 * Hash the foreign ip address
328 */
329 if (inc->inc_isipv6)
330 hash = HOSTCACHE_HASH6(&inc->inc6_faddr);
331 else
332 hash = HOSTCACHE_HASH(&inc->inc_faddr);
333
334 hc_head = &tcp_hostcache.hashbase[hash];
335
336 /*
337 * aquire lock for this bucket row
338 * we release the lock if we don't find an entry,
339 * otherwise the caller has to unlock after he is done
340 */
341 THC_LOCK(&hc_head->hch_mtx);
342
343 /*
344 * If the bucket limit is reached reuse the least used element
345 */
346 if (hc_head->hch_length >= tcp_hostcache.bucket_limit ||
347 tcp_hostcache.cache_count >= tcp_hostcache.cache_limit) {
348 hc_entry = TAILQ_LAST(&hc_head->hch_bucket, hc_qhead);
349 /*
350 * At first we were dropping the last element, just to
351 * reaquire it in the next two lines again which ain't
352 * very efficient. Instead just reuse the least used element.
353 * Maybe we drop something that is still "in-use" but we can
354 * be "lossy".
355 */
356 TAILQ_REMOVE(&hc_head->hch_bucket, hc_entry, rmx_q);
357 tcp_hostcache.hashbase[hash].hch_length--;
358 tcp_hostcache.cache_count--;
359 tcpstat.tcps_hc_bucketoverflow++;
360 #if 0
361 uma_zfree(tcp_hostcache.zone, hc_entry);
362 #endif
363 } else {
364 /*
365 * Allocate a new entry, or balk if not possible
366 */
367 hc_entry = uma_zalloc(tcp_hostcache.zone, M_NOWAIT);
368 if (hc_entry == NULL) {
369 THC_UNLOCK(&hc_head->hch_mtx);
370 return NULL;
371 }
372 }
373
374 /*
375 * Initialize basic information of hostcache entry
376 */
377 bzero(hc_entry, sizeof(*hc_entry));
378 if (inc->inc_isipv6)
379 bcopy(&inc->inc6_faddr, &hc_entry->ip6, sizeof(hc_entry->ip6));
380 else
381 hc_entry->ip4 = inc->inc_faddr;
382 hc_entry->rmx_head = hc_head;
383 hc_entry->rmx_expire = tcp_hostcache.expire;
384
385 /*
386 * Put it upfront
387 */
388 TAILQ_INSERT_HEAD(&hc_head->hch_bucket, hc_entry, rmx_q);
389 tcp_hostcache.hashbase[hash].hch_length++;
390 tcp_hostcache.cache_count++;
391 tcpstat.tcps_hc_added++;
392
393 return hc_entry;
394 }
395
396 /*
397 * External function: lookup an entry in the hostcache and fill out the
398 * supplied tcp metrics structure. Fills in null when no entry was found
399 * or a value is not set.
400 */
401 void
402 tcp_hc_get(struct in_conninfo *inc, struct hc_metrics_lite *hc_metrics_lite)
403 {
404 struct hc_metrics *hc_entry;
405
406 /*
407 * Find the right bucket
408 */
409 hc_entry = tcp_hc_lookup(inc);
410
411 /*
412 * If we don't have an existing object
413 */
414 if (hc_entry == NULL) {
415 bzero(hc_metrics_lite, sizeof(*hc_metrics_lite));
416 return;
417 }
418 hc_entry->rmx_hits++;
419 hc_entry->rmx_expire = tcp_hostcache.expire; /* start over again */
420
421 hc_metrics_lite->rmx_mtu = hc_entry->rmx_mtu;
422 hc_metrics_lite->rmx_ssthresh = hc_entry->rmx_ssthresh;
423 hc_metrics_lite->rmx_rtt = hc_entry->rmx_rtt;
424 hc_metrics_lite->rmx_rttvar = hc_entry->rmx_rttvar;
425 hc_metrics_lite->rmx_bandwidth = hc_entry->rmx_bandwidth;
426 hc_metrics_lite->rmx_cwnd = hc_entry->rmx_cwnd;
427 hc_metrics_lite->rmx_sendpipe = hc_entry->rmx_sendpipe;
428 hc_metrics_lite->rmx_recvpipe = hc_entry->rmx_recvpipe;
429
430 /*
431 * unlock bucket row
432 */
433 THC_UNLOCK(&hc_entry->rmx_head->hch_mtx);
434 }
435
436 /*
437 * External function: lookup an entry in the hostcache and return the
438 * discovered path mtu. Returns null if no entry is found or value is not
439 * set.
440 */
441 u_long
442 tcp_hc_getmtu(struct in_conninfo *inc)
443 {
444 struct hc_metrics *hc_entry;
445 u_long mtu;
446
447 hc_entry = tcp_hc_lookup(inc);
448 if (hc_entry == NULL) {
449 return 0;
450 }
451 hc_entry->rmx_hits++;
452 hc_entry->rmx_expire = tcp_hostcache.expire; /* start over again */
453
454 mtu = hc_entry->rmx_mtu;
455 THC_UNLOCK(&hc_entry->rmx_head->hch_mtx);
456 return mtu;
457 }
458
459 /*
460 * External function: update the mtu value of an entry in the hostcache.
461 * Creates a new entry if none was found.
462 */
463 void
464 tcp_hc_updatemtu(struct in_conninfo *inc, u_long mtu)
465 {
466 struct hc_metrics *hc_entry;
467
468 /*
469 * Find the right bucket
470 */
471 hc_entry = tcp_hc_lookup(inc);
472
473 /*
474 * If we don't have an existing object try to insert a new one
475 */
476 if (hc_entry == NULL) {
477 hc_entry = tcp_hc_insert(inc);
478 if (hc_entry == NULL)
479 return;
480 }
481 hc_entry->rmx_updates++;
482 hc_entry->rmx_expire = tcp_hostcache.expire; /* start over again */
483
484 hc_entry->rmx_mtu = mtu;
485
486 /*
487 * put it upfront so we find it faster next time
488 */
489 TAILQ_REMOVE(&hc_entry->rmx_head->hch_bucket, hc_entry, rmx_q);
490 TAILQ_INSERT_HEAD(&hc_entry->rmx_head->hch_bucket, hc_entry, rmx_q);
491
492 /*
493 * unlock bucket row
494 */
495 THC_UNLOCK(&hc_entry->rmx_head->hch_mtx);
496 }
497
498 /*
499 * External function: update the tcp metrics of an entry in the hostcache.
500 * Creates a new entry if none was found.
501 */
502 void
503 tcp_hc_update(struct in_conninfo *inc, struct hc_metrics_lite *hcml)
504 {
505 struct hc_metrics *hc_entry;
506
507 hc_entry = tcp_hc_lookup(inc);
508 if (hc_entry == NULL) {
509 hc_entry = tcp_hc_insert(inc);
510 if (hc_entry == NULL)
511 return;
512 }
513 hc_entry->rmx_updates++;
514 hc_entry->rmx_expire = tcp_hostcache.expire; /* start over again */
515
516 if (hcml->rmx_rtt != 0) {
517 if (hc_entry->rmx_rtt == 0)
518 hc_entry->rmx_rtt = hcml->rmx_rtt;
519 else
520 hc_entry->rmx_rtt =
521 (hc_entry->rmx_rtt + hcml->rmx_rtt) / 2;
522 tcpstat.tcps_cachedrtt++;
523 }
524 if (hcml->rmx_rttvar != 0) {
525 if (hc_entry->rmx_rttvar == 0)
526 hc_entry->rmx_rttvar = hcml->rmx_rttvar;
527 else
528 hc_entry->rmx_rttvar =
529 (hc_entry->rmx_rttvar + hcml->rmx_rttvar) / 2;
530 tcpstat.tcps_cachedrttvar++;
531 }
532 if (hcml->rmx_ssthresh != 0) {
533 if (hc_entry->rmx_ssthresh == 0)
534 hc_entry->rmx_ssthresh = hcml->rmx_ssthresh;
535 else
536 hc_entry->rmx_ssthresh =
537 (hc_entry->rmx_ssthresh + hcml->rmx_ssthresh) / 2;
538 tcpstat.tcps_cachedssthresh++;
539 }
540 if (hcml->rmx_bandwidth != 0) {
541 if (hc_entry->rmx_bandwidth == 0)
542 hc_entry->rmx_bandwidth = hcml->rmx_bandwidth;
543 else
544 hc_entry->rmx_bandwidth =
545 (hc_entry->rmx_bandwidth + hcml->rmx_bandwidth) / 2;
546 /* tcpstat.tcps_cachedbandwidth++; */
547 }
548 if (hcml->rmx_cwnd != 0) {
549 if (hc_entry->rmx_cwnd == 0)
550 hc_entry->rmx_cwnd = hcml->rmx_cwnd;
551 else
552 hc_entry->rmx_cwnd =
553 (hc_entry->rmx_cwnd + hcml->rmx_cwnd) / 2;
554 /* tcpstat.tcps_cachedcwnd++; */
555 }
556 if (hcml->rmx_sendpipe != 0) {
557 if (hc_entry->rmx_sendpipe == 0)
558 hc_entry->rmx_sendpipe = hcml->rmx_sendpipe;
559 else
560 hc_entry->rmx_sendpipe =
561 (hc_entry->rmx_sendpipe + hcml->rmx_sendpipe) /2;
562 /* tcpstat.tcps_cachedsendpipe++; */
563 }
564 if (hcml->rmx_recvpipe != 0) {
565 if (hc_entry->rmx_recvpipe == 0)
566 hc_entry->rmx_recvpipe = hcml->rmx_recvpipe;
567 else
568 hc_entry->rmx_recvpipe =
569 (hc_entry->rmx_recvpipe + hcml->rmx_recvpipe) /2;
570 /* tcpstat.tcps_cachedrecvpipe++; */
571 }
572
573 TAILQ_REMOVE(&hc_entry->rmx_head->hch_bucket, hc_entry, rmx_q);
574 TAILQ_INSERT_HEAD(&hc_entry->rmx_head->hch_bucket, hc_entry, rmx_q);
575 THC_UNLOCK(&hc_entry->rmx_head->hch_mtx);
576 }
577
578 /*
579 * Sysctl function: prints the list and values of all hostcache entries in
580 * unsorted order.
581 */
582 static int
583 sysctl_tcp_hc_list(SYSCTL_HANDLER_ARGS)
584 {
585 int bufsize;
586 int linesize = 128;
587 char *p, *buf;
588 int len, i, error;
589 struct hc_metrics *hc_entry;
590
591 bufsize = linesize * (tcp_hostcache.cache_count + 1);
592
593 p = buf = (char *)malloc(bufsize, M_TEMP, M_WAITOK|M_ZERO);
594
595 len = snprintf(p, linesize,
596 "\nIP address MTU SSTRESH RTT RTTVAR BANDWIDTH "
597 " CWND SENDPIPE RECVPIPE HITS UPD EXP\n");
598 p += len;
599
600 #define msec(u) (((u) + 500) / 1000)
601 for (i = 0; i < tcp_hostcache.hashsize; i++) {
602 THC_LOCK(&tcp_hostcache.hashbase[i].hch_mtx);
603 TAILQ_FOREACH(hc_entry, &tcp_hostcache.hashbase[i].hch_bucket,
604 rmx_q) {
605 len = snprintf(p, linesize,
606 "%-15s %5lu %8lu %6lums %6lums %9lu %8lu %8lu %8lu "
607 "%4lu %4lu %4i\n",
608 hc_entry->ip4.s_addr ? inet_ntoa(hc_entry->ip4) :
609 #ifdef INET6
610 ip6_sprintf(&hc_entry->ip6),
611 #else
612 "IPv6?",
613 #endif
614 hc_entry->rmx_mtu,
615 hc_entry->rmx_ssthresh,
616 msec(hc_entry->rmx_rtt *
617 (RTM_RTTUNIT / (hz * TCP_RTT_SCALE))),
618 msec(hc_entry->rmx_rttvar *
619 (RTM_RTTUNIT / (hz * TCP_RTT_SCALE))),
620 hc_entry->rmx_bandwidth * 8,
621 hc_entry->rmx_cwnd,
622 hc_entry->rmx_sendpipe,
623 hc_entry->rmx_recvpipe,
624 hc_entry->rmx_hits,
625 hc_entry->rmx_updates,
626 hc_entry->rmx_expire);
627 p += len;
628 }
629 THC_UNLOCK(&tcp_hostcache.hashbase[i].hch_mtx);
630 }
631 #undef msec
632 error = SYSCTL_OUT(req, buf, p - buf);
633 free(buf, M_TEMP);
634 return(error);
635 }
636
637 /*
638 * Expire and purge (old|all) entries in the tcp_hostcache. Runs periodically
639 * from the callout.
640 */
641 static void
642 tcp_hc_purge(void *arg)
643 {
644 struct hc_metrics *hc_entry, *hc_next;
645 int all = (intptr_t)arg;
646 int i;
647
648 if (tcp_hostcache.purgeall) {
649 all = 1;
650 tcp_hostcache.purgeall = 0;
651 }
652
653 for (i = 0; i < tcp_hostcache.hashsize; i++) {
654 THC_LOCK(&tcp_hostcache.hashbase[i].hch_mtx);
655 TAILQ_FOREACH_SAFE(hc_entry, &tcp_hostcache.hashbase[i].hch_bucket,
656 rmx_q, hc_next) {
657 if (all || hc_entry->rmx_expire <= 0) {
658 TAILQ_REMOVE(&tcp_hostcache.hashbase[i].hch_bucket,
659 hc_entry, rmx_q);
660 uma_zfree(tcp_hostcache.zone, hc_entry);
661 tcp_hostcache.hashbase[i].hch_length--;
662 tcp_hostcache.cache_count--;
663 } else
664 hc_entry->rmx_expire -= TCP_HOSTCACHE_PRUNE;
665 }
666 THC_UNLOCK(&tcp_hostcache.hashbase[i].hch_mtx);
667 }
668 callout_reset(&tcp_hc_callout, TCP_HOSTCACHE_PRUNE * hz, tcp_hc_purge, 0);
669 }
Cache object: d6508f8d7bf2b7d04c7643d80aad8313
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