2 * Copyright (c) 2002 Andre Oppermann, Internet Business Solutions AG
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
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
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
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, bandwidth, max
36 * MTU, congestion window) between local and remote sites, this can lead to
37 * significant speed-ups for new TCP connections after the first one.
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.
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.
61 * Many thanks to jlemon for basic structure of tcp_syncache which is being
65 #include <sys/cdefs.h>
66 __FBSDID("$FreeBSD$");
68 #include "opt_inet6.h"
70 #include <sys/param.h>
71 #include <sys/systm.h>
72 #include <sys/kernel.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>
81 #include <net/route.h>
84 #include <netinet/in.h>
85 #include <netinet/in_systm.h>
86 #include <netinet/ip.h>
87 #include <netinet/in_var.h>
88 #include <netinet/in_pcb.h>
89 #include <netinet/ip_var.h>
91 #include <netinet/ip6.h>
92 #include <netinet6/ip6_var.h>
94 #include <netinet/tcp.h>
95 #include <netinet/tcp_var.h>
96 #include <netinet/tcp_hostcache.h>
98 #include <netinet6/tcp6_var.h>
103 /* Arbitrary values */
104 #define TCP_HOSTCACHE_HASHSIZE 512
105 #define TCP_HOSTCACHE_BUCKETLIMIT 30
106 #define TCP_HOSTCACHE_EXPIRE 60*60 /* one hour */
107 #define TCP_HOSTCACHE_PRUNE 5*60 /* every 5 minutes */
109 static VNET_DEFINE(struct tcp_hostcache, tcp_hostcache);
110 #define V_tcp_hostcache VNET(tcp_hostcache)
112 static VNET_DEFINE(struct callout, tcp_hc_callout);
113 #define V_tcp_hc_callout VNET(tcp_hc_callout)
115 static struct hc_metrics *tcp_hc_lookup(struct in_conninfo *);
116 static struct hc_metrics *tcp_hc_insert(struct in_conninfo *);
117 static int sysctl_tcp_hc_list(SYSCTL_HANDLER_ARGS);
118 static void tcp_hc_purge_internal(int);
119 static void tcp_hc_purge(void *);
121 static SYSCTL_NODE(_net_inet_tcp, OID_AUTO, hostcache, CTLFLAG_RW, 0,
124 SYSCTL_VNET_UINT(_net_inet_tcp_hostcache, OID_AUTO, cachelimit, CTLFLAG_RDTUN,
125 &VNET_NAME(tcp_hostcache.cache_limit), 0,
126 "Overall entry limit for hostcache");
128 SYSCTL_VNET_UINT(_net_inet_tcp_hostcache, OID_AUTO, hashsize, CTLFLAG_RDTUN,
129 &VNET_NAME(tcp_hostcache.hashsize), 0,
130 "Size of TCP hostcache hashtable");
132 SYSCTL_VNET_UINT(_net_inet_tcp_hostcache, OID_AUTO, bucketlimit,
133 CTLFLAG_RDTUN, &VNET_NAME(tcp_hostcache.bucket_limit), 0,
134 "Per-bucket hash limit for hostcache");
136 SYSCTL_VNET_UINT(_net_inet_tcp_hostcache, OID_AUTO, count, CTLFLAG_RD,
137 &VNET_NAME(tcp_hostcache.cache_count), 0,
138 "Current number of entries in hostcache");
140 SYSCTL_VNET_INT(_net_inet_tcp_hostcache, OID_AUTO, expire, CTLFLAG_RW,
141 &VNET_NAME(tcp_hostcache.expire), 0,
142 "Expire time of TCP hostcache entries");
144 SYSCTL_VNET_INT(_net_inet_tcp_hostcache, OID_AUTO, prune, CTLFLAG_RW,
145 &VNET_NAME(tcp_hostcache.prune), 0,
146 "Time between purge runs");
148 SYSCTL_VNET_INT(_net_inet_tcp_hostcache, OID_AUTO, purge, CTLFLAG_RW,
149 &VNET_NAME(tcp_hostcache.purgeall), 0,
150 "Expire all entires on next purge run");
152 SYSCTL_PROC(_net_inet_tcp_hostcache, OID_AUTO, list,
153 CTLTYPE_STRING | CTLFLAG_RD | CTLFLAG_SKIP, 0, 0,
154 sysctl_tcp_hc_list, "A", "List of all hostcache entries");
157 static MALLOC_DEFINE(M_HOSTCACHE, "hostcache", "TCP hostcache");
159 #define HOSTCACHE_HASH(ip) \
160 (((ip)->s_addr ^ ((ip)->s_addr >> 7) ^ ((ip)->s_addr >> 17)) & \
161 V_tcp_hostcache.hashmask)
163 /* XXX: What is the recommended hash to get good entropy for IPv6 addresses? */
164 #define HOSTCACHE_HASH6(ip6) \
165 (((ip6)->s6_addr32[0] ^ \
166 (ip6)->s6_addr32[1] ^ \
167 (ip6)->s6_addr32[2] ^ \
168 (ip6)->s6_addr32[3]) & \
169 V_tcp_hostcache.hashmask)
171 #define THC_LOCK(lp) mtx_lock(lp)
172 #define THC_UNLOCK(lp) mtx_unlock(lp)
180 * Initialize hostcache structures.
182 V_tcp_hostcache.cache_count = 0;
183 V_tcp_hostcache.hashsize = TCP_HOSTCACHE_HASHSIZE;
184 V_tcp_hostcache.bucket_limit = TCP_HOSTCACHE_BUCKETLIMIT;
185 V_tcp_hostcache.cache_limit =
186 V_tcp_hostcache.hashsize * V_tcp_hostcache.bucket_limit;
187 V_tcp_hostcache.expire = TCP_HOSTCACHE_EXPIRE;
188 V_tcp_hostcache.prune = TCP_HOSTCACHE_PRUNE;
190 TUNABLE_INT_FETCH("net.inet.tcp.hostcache.hashsize",
191 &V_tcp_hostcache.hashsize);
192 TUNABLE_INT_FETCH("net.inet.tcp.hostcache.cachelimit",
193 &V_tcp_hostcache.cache_limit);
194 TUNABLE_INT_FETCH("net.inet.tcp.hostcache.bucketlimit",
195 &V_tcp_hostcache.bucket_limit);
196 if (!powerof2(V_tcp_hostcache.hashsize)) {
197 printf("WARNING: hostcache hash size is not a power of 2.\n");
198 V_tcp_hostcache.hashsize = TCP_HOSTCACHE_HASHSIZE; /* default */
200 V_tcp_hostcache.hashmask = V_tcp_hostcache.hashsize - 1;
203 * Allocate the hash table.
205 V_tcp_hostcache.hashbase = (struct hc_head *)
206 malloc(V_tcp_hostcache.hashsize * sizeof(struct hc_head),
207 M_HOSTCACHE, M_WAITOK | M_ZERO);
210 * Initialize the hash buckets.
212 for (i = 0; i < V_tcp_hostcache.hashsize; i++) {
213 TAILQ_INIT(&V_tcp_hostcache.hashbase[i].hch_bucket);
214 V_tcp_hostcache.hashbase[i].hch_length = 0;
215 mtx_init(&V_tcp_hostcache.hashbase[i].hch_mtx, "tcp_hc_entry",
220 * Allocate the hostcache entries.
222 V_tcp_hostcache.zone =
223 uma_zcreate("hostcache", sizeof(struct hc_metrics),
224 NULL, NULL, NULL, NULL, UMA_ALIGN_PTR, 0);
225 uma_zone_set_max(V_tcp_hostcache.zone, V_tcp_hostcache.cache_limit);
228 * Set up periodic cache cleanup.
230 callout_init(&V_tcp_hc_callout, CALLOUT_MPSAFE);
231 callout_reset(&V_tcp_hc_callout, V_tcp_hostcache.prune * hz,
232 tcp_hc_purge, curvnet);
241 callout_drain(&V_tcp_hc_callout);
243 /* Purge all hc entries. */
244 tcp_hc_purge_internal(1);
246 /* Free the uma zone and the allocated hash table. */
247 uma_zdestroy(V_tcp_hostcache.zone);
249 for (i = 0; i < V_tcp_hostcache.hashsize; i++)
250 mtx_destroy(&V_tcp_hostcache.hashbase[i].hch_mtx);
251 free(V_tcp_hostcache.hashbase, M_HOSTCACHE);
256 * Internal function: look up an entry in the hostcache or return NULL.
258 * If an entry has been returned, the caller becomes responsible for
259 * unlocking the bucket row after he is done reading/modifying the entry.
261 static struct hc_metrics *
262 tcp_hc_lookup(struct in_conninfo *inc)
265 struct hc_head *hc_head;
266 struct hc_metrics *hc_entry;
268 KASSERT(inc != NULL, ("tcp_hc_lookup with NULL in_conninfo pointer"));
271 * Hash the foreign ip address.
273 if (inc->inc_flags & INC_ISIPV6)
274 hash = HOSTCACHE_HASH6(&inc->inc6_faddr);
276 hash = HOSTCACHE_HASH(&inc->inc_faddr);
278 hc_head = &V_tcp_hostcache.hashbase[hash];
281 * Acquire lock for this bucket row; we release the lock if we don't
282 * find an entry, otherwise the caller has to unlock after he is
285 THC_LOCK(&hc_head->hch_mtx);
288 * Iterate through entries in bucket row looking for a match.
290 TAILQ_FOREACH(hc_entry, &hc_head->hch_bucket, rmx_q) {
291 if (inc->inc_flags & INC_ISIPV6) {
292 if (memcmp(&inc->inc6_faddr, &hc_entry->ip6,
293 sizeof(inc->inc6_faddr)) == 0)
296 if (memcmp(&inc->inc_faddr, &hc_entry->ip4,
297 sizeof(inc->inc_faddr)) == 0)
303 * We were unsuccessful and didn't find anything.
305 THC_UNLOCK(&hc_head->hch_mtx);
310 * Internal function: insert an entry into the hostcache or return NULL if
311 * unable to allocate a new one.
313 * If an entry has been returned, the caller becomes responsible for
314 * unlocking the bucket row after he is done reading/modifying the entry.
316 static struct hc_metrics *
317 tcp_hc_insert(struct in_conninfo *inc)
320 struct hc_head *hc_head;
321 struct hc_metrics *hc_entry;
323 KASSERT(inc != NULL, ("tcp_hc_insert with NULL in_conninfo pointer"));
326 * Hash the foreign ip address.
328 if (inc->inc_flags & INC_ISIPV6)
329 hash = HOSTCACHE_HASH6(&inc->inc6_faddr);
331 hash = HOSTCACHE_HASH(&inc->inc_faddr);
333 hc_head = &V_tcp_hostcache.hashbase[hash];
336 * Acquire lock for this bucket row; we release the lock if we don't
337 * find an entry, otherwise the caller has to unlock after he is
340 THC_LOCK(&hc_head->hch_mtx);
343 * If the bucket limit is reached, reuse the least-used element.
345 if (hc_head->hch_length >= V_tcp_hostcache.bucket_limit ||
346 V_tcp_hostcache.cache_count >= V_tcp_hostcache.cache_limit) {
347 hc_entry = TAILQ_LAST(&hc_head->hch_bucket, hc_qhead);
349 * At first we were dropping the last element, just to
350 * reacquire it in the next two lines again, which isn't very
351 * efficient. Instead just reuse the least used element.
352 * We may drop something that is still "in-use" but we can be
354 * Just give up if this bucket row is empty and we don't have
355 * anything to replace.
357 if (hc_entry == NULL) {
358 THC_UNLOCK(&hc_head->hch_mtx);
361 TAILQ_REMOVE(&hc_head->hch_bucket, hc_entry, rmx_q);
362 V_tcp_hostcache.hashbase[hash].hch_length--;
363 V_tcp_hostcache.cache_count--;
364 TCPSTAT_INC(tcps_hc_bucketoverflow);
366 uma_zfree(V_tcp_hostcache.zone, hc_entry);
370 * Allocate a new entry, or balk if not possible.
372 hc_entry = uma_zalloc(V_tcp_hostcache.zone, M_NOWAIT);
373 if (hc_entry == NULL) {
374 THC_UNLOCK(&hc_head->hch_mtx);
380 * Initialize basic information of hostcache entry.
382 bzero(hc_entry, sizeof(*hc_entry));
383 if (inc->inc_flags & INC_ISIPV6)
384 bcopy(&inc->inc6_faddr, &hc_entry->ip6, sizeof(hc_entry->ip6));
386 hc_entry->ip4 = inc->inc_faddr;
387 hc_entry->rmx_head = hc_head;
388 hc_entry->rmx_expire = V_tcp_hostcache.expire;
393 TAILQ_INSERT_HEAD(&hc_head->hch_bucket, hc_entry, rmx_q);
394 V_tcp_hostcache.hashbase[hash].hch_length++;
395 V_tcp_hostcache.cache_count++;
396 TCPSTAT_INC(tcps_hc_added);
402 * External function: look up an entry in the hostcache and fill out the
403 * supplied TCP metrics structure. Fills in NULL when no entry was found or
404 * a value is not set.
407 tcp_hc_get(struct in_conninfo *inc, struct hc_metrics_lite *hc_metrics_lite)
409 struct hc_metrics *hc_entry;
412 * Find the right bucket.
414 hc_entry = tcp_hc_lookup(inc);
417 * If we don't have an existing object.
419 if (hc_entry == NULL) {
420 bzero(hc_metrics_lite, sizeof(*hc_metrics_lite));
423 hc_entry->rmx_hits++;
424 hc_entry->rmx_expire = V_tcp_hostcache.expire; /* start over again */
426 hc_metrics_lite->rmx_mtu = hc_entry->rmx_mtu;
427 hc_metrics_lite->rmx_ssthresh = hc_entry->rmx_ssthresh;
428 hc_metrics_lite->rmx_rtt = hc_entry->rmx_rtt;
429 hc_metrics_lite->rmx_rttvar = hc_entry->rmx_rttvar;
430 hc_metrics_lite->rmx_bandwidth = hc_entry->rmx_bandwidth;
431 hc_metrics_lite->rmx_cwnd = hc_entry->rmx_cwnd;
432 hc_metrics_lite->rmx_sendpipe = hc_entry->rmx_sendpipe;
433 hc_metrics_lite->rmx_recvpipe = hc_entry->rmx_recvpipe;
438 THC_UNLOCK(&hc_entry->rmx_head->hch_mtx);
442 * External function: look up an entry in the hostcache and return the
443 * discovered path MTU. Returns NULL if no entry is found or value is not
447 tcp_hc_getmtu(struct in_conninfo *inc)
449 struct hc_metrics *hc_entry;
452 hc_entry = tcp_hc_lookup(inc);
453 if (hc_entry == NULL) {
456 hc_entry->rmx_hits++;
457 hc_entry->rmx_expire = V_tcp_hostcache.expire; /* start over again */
459 mtu = hc_entry->rmx_mtu;
460 THC_UNLOCK(&hc_entry->rmx_head->hch_mtx);
465 * External function: update the MTU value of an entry in the hostcache.
466 * Creates a new entry if none was found.
469 tcp_hc_updatemtu(struct in_conninfo *inc, u_long mtu)
471 struct hc_metrics *hc_entry;
474 * Find the right bucket.
476 hc_entry = tcp_hc_lookup(inc);
479 * If we don't have an existing object, try to insert a new one.
481 if (hc_entry == NULL) {
482 hc_entry = tcp_hc_insert(inc);
483 if (hc_entry == NULL)
486 hc_entry->rmx_updates++;
487 hc_entry->rmx_expire = V_tcp_hostcache.expire; /* start over again */
489 hc_entry->rmx_mtu = mtu;
492 * Put it upfront so we find it faster next time.
494 TAILQ_REMOVE(&hc_entry->rmx_head->hch_bucket, hc_entry, rmx_q);
495 TAILQ_INSERT_HEAD(&hc_entry->rmx_head->hch_bucket, hc_entry, rmx_q);
500 THC_UNLOCK(&hc_entry->rmx_head->hch_mtx);
504 * External function: update the TCP metrics of an entry in the hostcache.
505 * Creates a new entry if none was found.
508 tcp_hc_update(struct in_conninfo *inc, struct hc_metrics_lite *hcml)
510 struct hc_metrics *hc_entry;
512 hc_entry = tcp_hc_lookup(inc);
513 if (hc_entry == NULL) {
514 hc_entry = tcp_hc_insert(inc);
515 if (hc_entry == NULL)
518 hc_entry->rmx_updates++;
519 hc_entry->rmx_expire = V_tcp_hostcache.expire; /* start over again */
521 if (hcml->rmx_rtt != 0) {
522 if (hc_entry->rmx_rtt == 0)
523 hc_entry->rmx_rtt = hcml->rmx_rtt;
526 (hc_entry->rmx_rtt + hcml->rmx_rtt) / 2;
527 TCPSTAT_INC(tcps_cachedrtt);
529 if (hcml->rmx_rttvar != 0) {
530 if (hc_entry->rmx_rttvar == 0)
531 hc_entry->rmx_rttvar = hcml->rmx_rttvar;
533 hc_entry->rmx_rttvar =
534 (hc_entry->rmx_rttvar + hcml->rmx_rttvar) / 2;
535 TCPSTAT_INC(tcps_cachedrttvar);
537 if (hcml->rmx_ssthresh != 0) {
538 if (hc_entry->rmx_ssthresh == 0)
539 hc_entry->rmx_ssthresh = hcml->rmx_ssthresh;
541 hc_entry->rmx_ssthresh =
542 (hc_entry->rmx_ssthresh + hcml->rmx_ssthresh) / 2;
543 TCPSTAT_INC(tcps_cachedssthresh);
545 if (hcml->rmx_bandwidth != 0) {
546 if (hc_entry->rmx_bandwidth == 0)
547 hc_entry->rmx_bandwidth = hcml->rmx_bandwidth;
549 hc_entry->rmx_bandwidth =
550 (hc_entry->rmx_bandwidth + hcml->rmx_bandwidth) / 2;
551 /* TCPSTAT_INC(tcps_cachedbandwidth); */
553 if (hcml->rmx_cwnd != 0) {
554 if (hc_entry->rmx_cwnd == 0)
555 hc_entry->rmx_cwnd = hcml->rmx_cwnd;
558 (hc_entry->rmx_cwnd + hcml->rmx_cwnd) / 2;
559 /* TCPSTAT_INC(tcps_cachedcwnd); */
561 if (hcml->rmx_sendpipe != 0) {
562 if (hc_entry->rmx_sendpipe == 0)
563 hc_entry->rmx_sendpipe = hcml->rmx_sendpipe;
565 hc_entry->rmx_sendpipe =
566 (hc_entry->rmx_sendpipe + hcml->rmx_sendpipe) /2;
567 /* TCPSTAT_INC(tcps_cachedsendpipe); */
569 if (hcml->rmx_recvpipe != 0) {
570 if (hc_entry->rmx_recvpipe == 0)
571 hc_entry->rmx_recvpipe = hcml->rmx_recvpipe;
573 hc_entry->rmx_recvpipe =
574 (hc_entry->rmx_recvpipe + hcml->rmx_recvpipe) /2;
575 /* TCPSTAT_INC(tcps_cachedrecvpipe); */
578 TAILQ_REMOVE(&hc_entry->rmx_head->hch_bucket, hc_entry, rmx_q);
579 TAILQ_INSERT_HEAD(&hc_entry->rmx_head->hch_bucket, hc_entry, rmx_q);
580 THC_UNLOCK(&hc_entry->rmx_head->hch_mtx);
584 * Sysctl function: prints the list and values of all hostcache entries in
588 sysctl_tcp_hc_list(SYSCTL_HANDLER_ARGS)
594 struct hc_metrics *hc_entry;
596 char ip6buf[INET6_ADDRSTRLEN];
599 bufsize = linesize * (V_tcp_hostcache.cache_count + 1);
601 p = buf = (char *)malloc(bufsize, M_TEMP, M_WAITOK|M_ZERO);
603 len = snprintf(p, linesize,
604 "\nIP address MTU SSTRESH RTT RTTVAR BANDWIDTH "
605 " CWND SENDPIPE RECVPIPE HITS UPD EXP\n");
608 #define msec(u) (((u) + 500) / 1000)
609 for (i = 0; i < V_tcp_hostcache.hashsize; i++) {
610 THC_LOCK(&V_tcp_hostcache.hashbase[i].hch_mtx);
611 TAILQ_FOREACH(hc_entry, &V_tcp_hostcache.hashbase[i].hch_bucket,
613 len = snprintf(p, linesize,
614 "%-15s %5lu %8lu %6lums %6lums %9lu %8lu %8lu %8lu "
616 hc_entry->ip4.s_addr ? inet_ntoa(hc_entry->ip4) :
618 ip6_sprintf(ip6buf, &hc_entry->ip6),
623 hc_entry->rmx_ssthresh,
624 msec(hc_entry->rmx_rtt *
625 (RTM_RTTUNIT / (hz * TCP_RTT_SCALE))),
626 msec(hc_entry->rmx_rttvar *
627 (RTM_RTTUNIT / (hz * TCP_RTT_SCALE))),
628 hc_entry->rmx_bandwidth * 8,
630 hc_entry->rmx_sendpipe,
631 hc_entry->rmx_recvpipe,
633 hc_entry->rmx_updates,
634 hc_entry->rmx_expire);
637 THC_UNLOCK(&V_tcp_hostcache.hashbase[i].hch_mtx);
640 error = SYSCTL_OUT(req, buf, p - buf);
646 * Caller has to make sure the curvnet is set properly.
649 tcp_hc_purge_internal(int all)
651 struct hc_metrics *hc_entry, *hc_next;
654 for (i = 0; i < V_tcp_hostcache.hashsize; i++) {
655 THC_LOCK(&V_tcp_hostcache.hashbase[i].hch_mtx);
656 TAILQ_FOREACH_SAFE(hc_entry,
657 &V_tcp_hostcache.hashbase[i].hch_bucket, rmx_q, hc_next) {
658 if (all || hc_entry->rmx_expire <= 0) {
659 TAILQ_REMOVE(&V_tcp_hostcache.hashbase[i].hch_bucket,
661 uma_zfree(V_tcp_hostcache.zone, hc_entry);
662 V_tcp_hostcache.hashbase[i].hch_length--;
663 V_tcp_hostcache.cache_count--;
665 hc_entry->rmx_expire -= V_tcp_hostcache.prune;
667 THC_UNLOCK(&V_tcp_hostcache.hashbase[i].hch_mtx);
672 * Expire and purge (old|all) entries in the tcp_hostcache. Runs
673 * periodically from the callout.
676 tcp_hc_purge(void *arg)
678 CURVNET_SET((struct vnet *) arg);
681 if (V_tcp_hostcache.purgeall) {
683 V_tcp_hostcache.purgeall = 0;
686 tcp_hc_purge_internal(all);
688 callout_reset(&V_tcp_hc_callout, V_tcp_hostcache.prune * hz,