/*-
* Copyright (c) 2002 Andre Oppermann, Internet Business Solutions AG
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. The name of the author may not be used to endorse or promote
* products derived from this software without specific prior written
* permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* $FreeBSD$
*/
/*
* The tcp_hostcache moves the tcp specific cached metrics from the routing
* table into a dedicated structure indexed by the remote IP address. It
* keeps information on the measured tcp parameters of past tcp sessions
* to have better initial start values for following connections from the
* same source. Depending on the network parameters (delay, bandwidth, max
* MTU, congestion window) between local and remote site this can lead to
* significant speedups for new tcp connections after the first one.
*
* Due to this new tcp_hostcache all tcp specific metrics information in
* the routing table has been removed. The INPCB no longer keeps a pointer
* to the routing entry and protocol initiated route cloning has been
* removed as well. With these changes the routing table has gone back
* to being more lightwight and only carries information related to packet
* forwarding.
*
* Tcp_hostcache is designed for multiple concurrent access in SMP
* environments and high contention. All bucket rows have their own
* lock and thus multiple lookups and modifies can be done at the same
* time as long as they are in different bucket rows. If a request for
* insertion of a new record can't be satisfied it simply returns an
* empty structure. Nobody and nothing shall ever point directly to
* any entry in tcp_hostcache. All communication is done in an object
* oriented way and only funtions of tcp_hostcache will manipulate hostcache
* entries. Otherwise we are unable to achieve good behaviour in concurrent
* access situations. Since tcp_hostcache is only caching information there
* are no fatal consequences if we either can't satisfy any particular request
* or have to drop/overwrite an existing entry because of bucket limit
* memory constrains.
*/
/*
* Many thanks to jlemon for basic structure of tcp_syncache which is being
* followed here.
*/
#include "opt_inet6.h"
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/lock.h>
#include <sys/mutex.h>
#include <sys/malloc.h>
#include <sys/socket.h>
#include <sys/socketvar.h>
#include <sys/sysctl.h>
#include <net/if.h>
#include <netinet/in.h>
#include <netinet/in_systm.h>
#include <netinet/ip.h>
#include <netinet/in_var.h>
#include <netinet/in_pcb.h>
#include <netinet/ip_var.h>
#ifdef INET6
#include <netinet/ip6.h>
#include <netinet6/ip6_var.h>
#endif
#include <netinet/tcp.h>
#include <netinet/tcp_var.h>
#ifdef INET6
#include <netinet6/tcp6_var.h>
#endif
#include <vm/uma.h>
TAILQ_HEAD(hc_qhead, hc_metrics);
struct hc_head {
struct hc_qhead hch_bucket;
u_int hch_length;
struct mtx hch_mtx;
};
struct hc_metrics {
/* housekeeping */
TAILQ_ENTRY(hc_metrics) rmx_q;
struct hc_head *rmx_head; /* head of bucket tail queue */
struct in_addr ip4; /* IP address */
struct in6_addr ip6; /* IP6 address */
/* endpoint specific values for tcp */
u_long rmx_mtu; /* MTU for this path */
u_long rmx_ssthresh; /* outbound gateway buffer limit */
u_long rmx_rtt; /* estimated round trip time */
u_long rmx_rttvar; /* estimated rtt variance */
u_long rmx_bandwidth; /* estimated bandwidth */
u_long rmx_cwnd; /* congestion window */
u_long rmx_sendpipe; /* outbound delay-bandwidth product */
u_long rmx_recvpipe; /* inbound delay-bandwidth product */
/* tcp hostcache internal data */
int rmx_expire; /* lifetime for object */
u_long rmx_hits; /* number of hits */
u_long rmx_updates; /* number of updates */
};
/* Arbitrary values */
#define TCP_HOSTCACHE_HASHSIZE 512
#define TCP_HOSTCACHE_BUCKETLIMIT 30
#define TCP_HOSTCACHE_EXPIRE 60*60 /* one hour */
#define TCP_HOSTCACHE_PRUNE 5*60 /* every 5 minutes */
struct tcp_hostcache {
struct hc_head *hashbase;
uma_zone_t zone;
u_int hashsize;
u_int hashmask;
u_int bucket_limit;
u_int cache_count;
u_int cache_limit;
int expire;
int purgeall;
};
static struct tcp_hostcache tcp_hostcache;
static struct callout tcp_hc_callout;
static struct hc_metrics *tcp_hc_lookup(struct in_conninfo *);
static struct hc_metrics *tcp_hc_insert(struct in_conninfo *);
static int sysctl_tcp_hc_list(SYSCTL_HANDLER_ARGS);
static void tcp_hc_purge(void *);
SYSCTL_NODE(_net_inet_tcp, OID_AUTO, hostcache, CTLFLAG_RW, 0, "TCP Host cache");
SYSCTL_INT(_net_inet_tcp_hostcache, OID_AUTO, cachelimit, CTLFLAG_RDTUN,
&tcp_hostcache.cache_limit, 0, "Overall entry limit for hostcache");
SYSCTL_INT(_net_inet_tcp_hostcache, OID_AUTO, hashsize, CTLFLAG_RDTUN,
&tcp_hostcache.hashsize, 0, "Size of TCP hostcache hashtable");
SYSCTL_INT(_net_inet_tcp_hostcache, OID_AUTO, bucketlimit, CTLFLAG_RDTUN,
&tcp_hostcache.bucket_limit, 0, "Per-bucket hash limit for hostcache");
SYSCTL_INT(_net_inet_tcp_hostcache, OID_AUTO, count, CTLFLAG_RD,
&tcp_hostcache.cache_count, 0, "Current number of entries in hostcache");
SYSCTL_INT(_net_inet_tcp_hostcache, OID_AUTO, expire, CTLFLAG_RW,
&tcp_hostcache.expire, 0, "Expire time of TCP hostcache entries");
SYSCTL_INT(_net_inet_tcp_hostcache, OID_AUTO, purge, CTLFLAG_RW,
&tcp_hostcache.purgeall, 0, "Expire all entires on next purge run");
SYSCTL_PROC(_net_inet_tcp_hostcache, OID_AUTO, list,
CTLTYPE_STRING | CTLFLAG_RD | CTLFLAG_SKIP, 0, 0,
sysctl_tcp_hc_list, "A", "List of all hostcache entries");
static MALLOC_DEFINE(M_HOSTCACHE, "hostcache", "TCP hostcache");
#define HOSTCACHE_HASH(ip) \
(((ip)->s_addr ^ ((ip)->s_addr >> 7) ^ ((ip)->s_addr >> 17)) & \
tcp_hostcache.hashmask)
/* XXX: What is the recommended hash to get good entropy for IPv6 addresses? */
#define HOSTCACHE_HASH6(ip6) \
(((ip6)->s6_addr32[0] ^ \
(ip6)->s6_addr32[1] ^ \
(ip6)->s6_addr32[2] ^ \
(ip6)->s6_addr32[3]) & \
tcp_hostcache.hashmask)
#define THC_LOCK(lp) mtx_lock(lp)
#define THC_UNLOCK(lp) mtx_unlock(lp)
void
tcp_hc_init(void)
{
int i;
/*
* Initialize hostcache structures
*/
tcp_hostcache.cache_count = 0;
tcp_hostcache.hashsize = TCP_HOSTCACHE_HASHSIZE;
tcp_hostcache.bucket_limit = TCP_HOSTCACHE_BUCKETLIMIT;
tcp_hostcache.cache_limit =
tcp_hostcache.hashsize * tcp_hostcache.bucket_limit;
tcp_hostcache.expire = TCP_HOSTCACHE_EXPIRE;
TUNABLE_INT_FETCH("net.inet.tcp.hostcache.hashsize",
&tcp_hostcache.hashsize);
TUNABLE_INT_FETCH("net.inet.tcp.hostcache.cachelimit",
&tcp_hostcache.cache_limit);
TUNABLE_INT_FETCH("net.inet.tcp.hostcache.bucketlimit",
&tcp_hostcache.bucket_limit);
if (!powerof2(tcp_hostcache.hashsize)) {
printf("WARNING: hostcache hash size is not a power of 2.\n");
tcp_hostcache.hashsize = 512; /* safe default */
}
tcp_hostcache.hashmask = tcp_hostcache.hashsize - 1;
/*
* Allocate the hash table
*/
tcp_hostcache.hashbase = (struct hc_head *)
malloc(tcp_hostcache.hashsize * sizeof(struct hc_head),
M_HOSTCACHE, M_WAITOK | M_ZERO);
/*
* Initialize the hash buckets
*/
for (i = 0; i < tcp_hostcache.hashsize; i++) {
TAILQ_INIT(&tcp_hostcache.hashbase[i].hch_bucket);
tcp_hostcache.hashbase[i].hch_length = 0;
mtx_init(&tcp_hostcache.hashbase[i].hch_mtx, "tcp_hc_entry",
NULL, MTX_DEF);
}
/*
* Allocate the hostcache entries.
*/
tcp_hostcache.zone = uma_zcreate("hostcache", sizeof(struct hc_metrics),
NULL, NULL, NULL, NULL, UMA_ALIGN_PTR, 0);
uma_zone_set_max(tcp_hostcache.zone, tcp_hostcache.cache_limit);
/*
* Set up periodic cache cleanup.
*/
callout_init(&tcp_hc_callout, CALLOUT_MPSAFE);
callout_reset(&tcp_hc_callout, TCP_HOSTCACHE_PRUNE * hz, tcp_hc_purge, 0);
}
/*
* Internal function: lookup an entry in the hostcache or return NULL.
*
* If an entry has been returned, the caller becomes responsible for
* unlocking the bucket row after he is done reading/modifying the entry.
*/
static struct hc_metrics *
tcp_hc_lookup(struct in_conninfo *inc)
{
int hash;
struct hc_head *hc_head;
struct hc_metrics *hc_entry;
KASSERT(inc != NULL, ("tcp_hc_lookup with NULL in_conninfo pointer"));
/*
* Hash the foreign ip address.
*/
if (inc->inc_isipv6)
hash = HOSTCACHE_HASH6(&inc->inc6_faddr);
else
hash = HOSTCACHE_HASH(&inc->inc_faddr);
hc_head = &tcp_hostcache.hashbase[hash];
/*
* aquire lock for this bucket row
* we release the lock if we don't find an entry,
* otherwise the caller has to unlock after he is done
*/
THC_LOCK(&hc_head->hch_mtx);
/*
* circle through entries in bucket row looking for a match
*/
TAILQ_FOREACH(hc_entry, &hc_head->hch_bucket, rmx_q) {
if (inc->inc_isipv6) {
if (memcmp(&inc->inc6_faddr, &hc_entry->ip6,
sizeof(inc->inc6_faddr)) == 0)
return hc_entry;
} else {
if (memcmp(&inc->inc_faddr, &hc_entry->ip4,
sizeof(inc->inc_faddr)) == 0)
return hc_entry;
}
}
/*
* We were unsuccessful and didn't find anything
*/
THC_UNLOCK(&hc_head->hch_mtx);
return NULL;
}
/*
* Internal function: insert an entry into the hostcache or return NULL
* if unable to allocate a new one.
*
* If an entry has been returned, the caller becomes responsible for
* unlocking the bucket row after he is done reading/modifying the entry.
*/
static struct hc_metrics *
tcp_hc_insert(struct in_conninfo *inc)
{
int hash;
struct hc_head *hc_head;
struct hc_metrics *hc_entry;
KASSERT(inc != NULL, ("tcp_hc_insert with NULL in_conninfo pointer"));
/*
* Hash the foreign ip address
*/
if (inc->inc_isipv6)
hash = HOSTCACHE_HASH6(&inc->inc6_faddr);
else
hash = HOSTCACHE_HASH(&inc->inc_faddr);
hc_head = &tcp_hostcache.hashbase[hash];
/*
* aquire lock for this bucket row
* we release the lock if we don't find an entry,
* otherwise the caller has to unlock after he is done
*/
THC_LOCK(&hc_head->hch_mtx);
/*
* If the bucket limit is reached reuse the least used element
*/
if (hc_head->hch_length >= tcp_hostcache.bucket_limit ||
tcp_hostcache.cache_count >= tcp_hostcache.cache_limit) {
hc_entry = TAILQ_LAST(&hc_head->hch_bucket, hc_qhead);
/*
* At first we were dropping the last element, just to
* reaquire it in the next two lines again which ain't
* very efficient. Instead just reuse the least used element.
* Maybe we drop something that is still "in-use" but we can
* be "lossy".
*/
TAILQ_REMOVE(&hc_head->hch_bucket, hc_entry, rmx_q);
tcp_hostcache.hashbase[hash].hch_length--;
tcp_hostcache.cache_count--;
tcpstat.tcps_hc_bucketoverflow++;
#if 0
uma_zfree(tcp_hostcache.zone, hc_entry);
#endif
} else {
/*
* Allocate a new entry, or balk if not possible
*/
hc_entry = uma_zalloc(tcp_hostcache.zone, M_NOWAIT);
if (hc_entry == NULL) {
THC_UNLOCK(&hc_head->hch_mtx);
return NULL;
}
}
/*
* Initialize basic information of hostcache entry
*/
bzero(hc_entry, sizeof(*hc_entry));
if (inc->inc_isipv6)
bcopy(&inc->inc6_faddr, &hc_entry->ip6, sizeof(hc_entry->ip6));
else
hc_entry->ip4 = inc->inc_faddr;
hc_entry->rmx_head = hc_head;
hc_entry->rmx_expire = tcp_hostcache.expire;
/*
* Put it upfront
*/
TAILQ_INSERT_HEAD(&hc_head->hch_bucket, hc_entry, rmx_q);
tcp_hostcache.hashbase[hash].hch_length++;
tcp_hostcache.cache_count++;
tcpstat.tcps_hc_added++;
return hc_entry;
}
/*
* External function: lookup an entry in the hostcache and fill out the
* supplied tcp metrics structure. Fills in null when no entry was found
* or a value is not set.
*/
void
tcp_hc_get(struct in_conninfo *inc, struct hc_metrics_lite *hc_metrics_lite)
{
struct hc_metrics *hc_entry;
/*
* Find the right bucket
*/
hc_entry = tcp_hc_lookup(inc);
/*
* If we don't have an existing object
*/
if (hc_entry == NULL) {
bzero(hc_metrics_lite, sizeof(*hc_metrics_lite));
return;
}
hc_entry->rmx_hits++;
hc_entry->rmx_expire = tcp_hostcache.expire; /* start over again */
hc_metrics_lite->rmx_mtu = hc_entry->rmx_mtu;
hc_metrics_lite->rmx_ssthresh = hc_entry->rmx_ssthresh;
hc_metrics_lite->rmx_rtt = hc_entry->rmx_rtt;
hc_metrics_lite->rmx_rttvar = hc_entry->rmx_rttvar;
hc_metrics_lite->rmx_bandwidth = hc_entry->rmx_bandwidth;
hc_metrics_lite->rmx_cwnd = hc_entry->rmx_cwnd;
hc_metrics_lite->rmx_sendpipe = hc_entry->rmx_sendpipe;
hc_metrics_lite->rmx_recvpipe = hc_entry->rmx_recvpipe;
/*
* unlock bucket row
*/
THC_UNLOCK(&hc_entry->rmx_head->hch_mtx);
}
/*
* External function: lookup an entry in the hostcache and return the
* discovered path mtu. Returns null if no entry is found or value is not
* set.
*/
u_long
tcp_hc_getmtu(struct in_conninfo *inc)
{
struct hc_metrics *hc_entry;
u_long mtu;
hc_entry = tcp_hc_lookup(inc);
if (hc_entry == NULL) {
return 0;
}
hc_entry->rmx_hits++;
hc_entry->rmx_expire = tcp_hostcache.expire; /* start over again */
mtu = hc_entry->rmx_mtu;
THC_UNLOCK(&hc_entry->rmx_head->hch_mtx);
return mtu;
}
/*
* External function: update the mtu value of an entry in the hostcache.
* Creates a new entry if none was found.
*/
void
tcp_hc_updatemtu(struct in_conninfo *inc, u_long mtu)
{
struct hc_metrics *hc_entry;
/*
* Find the right bucket
*/
hc_entry = tcp_hc_lookup(inc);
/*
* If we don't have an existing object try to insert a new one
*/
if (hc_entry == NULL) {
hc_entry = tcp_hc_insert(inc);
if (hc_entry == NULL)
return;
}
hc_entry->rmx_updates++;
hc_entry->rmx_expire = tcp_hostcache.expire; /* start over again */
hc_entry->rmx_mtu = mtu;
/*
* put it upfront so we find it faster next time
*/
TAILQ_REMOVE(&hc_entry->rmx_head->hch_bucket, hc_entry, rmx_q);
TAILQ_INSERT_HEAD(&hc_entry->rmx_head->hch_bucket, hc_entry, rmx_q);
/*
* unlock bucket row
*/
THC_UNLOCK(&hc_entry->rmx_head->hch_mtx);
}
/*
* External function: update the tcp metrics of an entry in the hostcache.
* Creates a new entry if none was found.
*/
void
tcp_hc_update(struct in_conninfo *inc, struct hc_metrics_lite *hcml)
{
struct hc_metrics *hc_entry;
hc_entry = tcp_hc_lookup(inc);
if (hc_entry == NULL) {
hc_entry = tcp_hc_insert(inc);
if (hc_entry == NULL)
return;
}
hc_entry->rmx_updates++;
hc_entry->rmx_expire = tcp_hostcache.expire; /* start over again */
if (hcml->rmx_rtt != 0) {
if (hc_entry->rmx_rtt == 0)
hc_entry->rmx_rtt = hcml->rmx_rtt;
else
hc_entry->rmx_rtt =
(hc_entry->rmx_rtt + hcml->rmx_rtt) / 2;
tcpstat.tcps_cachedrtt++;
}
if (hcml->rmx_rttvar != 0) {
if (hc_entry->rmx_rttvar == 0)
hc_entry->rmx_rttvar = hcml->rmx_rttvar;
else
hc_entry->rmx_rttvar =
(hc_entry->rmx_rttvar + hcml->rmx_rttvar) / 2;
tcpstat.tcps_cachedrttvar++;
}
if (hcml->rmx_ssthresh != 0) {
if (hc_entry->rmx_ssthresh == 0)
hc_entry->rmx_ssthresh = hcml->rmx_ssthresh;
else
hc_entry->rmx_ssthresh =
(hc_entry->rmx_ssthresh + hcml->rmx_ssthresh) / 2;
tcpstat.tcps_cachedssthresh++;
}
if (hcml->rmx_bandwidth != 0) {
if (hc_entry->rmx_bandwidth == 0)
hc_entry->rmx_bandwidth = hcml->rmx_bandwidth;
else
hc_entry->rmx_bandwidth =
(hc_entry->rmx_bandwidth + hcml->rmx_bandwidth) / 2;
/* tcpstat.tcps_cachedbandwidth++; */
}
if (hcml->rmx_cwnd != 0) {
if (hc_entry->rmx_cwnd == 0)
hc_entry->rmx_cwnd = hcml->rmx_cwnd;
else
hc_entry->rmx_cwnd =
(hc_entry->rmx_cwnd + hcml->rmx_cwnd) / 2;
/* tcpstat.tcps_cachedcwnd++; */
}
if (hcml->rmx_sendpipe != 0) {
if (hc_entry->rmx_sendpipe == 0)
hc_entry->rmx_sendpipe = hcml->rmx_sendpipe;
else
hc_entry->rmx_sendpipe =
(hc_entry->rmx_sendpipe + hcml->rmx_sendpipe) /2;
/* tcpstat.tcps_cachedsendpipe++; */
}
if (hcml->rmx_recvpipe != 0) {
if (hc_entry->rmx_recvpipe == 0)
hc_entry->rmx_recvpipe = hcml->rmx_recvpipe;
else
hc_entry->rmx_recvpipe =
(hc_entry->rmx_recvpipe + hcml->rmx_recvpipe) /2;
/* tcpstat.tcps_cachedrecvpipe++; */
}
TAILQ_REMOVE(&hc_entry->rmx_head->hch_bucket, hc_entry, rmx_q);
TAILQ_INSERT_HEAD(&hc_entry->rmx_head->hch_bucket, hc_entry, rmx_q);
THC_UNLOCK(&hc_entry->rmx_head->hch_mtx);
}
/*
* Sysctl function: prints the list and values of all hostcache entries in
* unsorted order.
*/
static int
sysctl_tcp_hc_list(SYSCTL_HANDLER_ARGS)
{
int bufsize;
int linesize = 128;
char *p, *buf;
int len, i, error;
struct hc_metrics *hc_entry;
bufsize = linesize * (tcp_hostcache.cache_count + 1);
p = buf = (char *)malloc(bufsize, M_TEMP, M_WAITOK|M_ZERO);
len = snprintf(p, linesize,
"\nIP address MTU SSTRESH RTT RTTVAR BANDWIDTH "
" CWND SENDPIPE RECVPIPE HITS UPD EXP\n");
p += len;
#define msec(u) (((u) + 500) / 1000)
for (i = 0; i < tcp_hostcache.hashsize; i++) {
THC_LOCK(&tcp_hostcache.hashbase[i].hch_mtx);
TAILQ_FOREACH(hc_entry, &tcp_hostcache.hashbase[i].hch_bucket,
rmx_q) {
len = snprintf(p, linesize,
"%-15s %5lu %8lu %6lums %6lums %9lu %8lu %8lu %8lu "
"%4lu %4lu %4i\n",
hc_entry->ip4.s_addr ? inet_ntoa(hc_entry->ip4) :
#ifdef INET6
ip6_sprintf(&hc_entry->ip6),
#else
"IPv6?",
#endif
hc_entry->rmx_mtu,
hc_entry->rmx_ssthresh,
msec(hc_entry->rmx_rtt *
(RTM_RTTUNIT / (hz * TCP_RTT_SCALE))),
msec(hc_entry->rmx_rttvar *
(RTM_RTTUNIT / (hz * TCP_RTT_SCALE))),
hc_entry->rmx_bandwidth * 8,
hc_entry->rmx_cwnd,
hc_entry->rmx_sendpipe,
hc_entry->rmx_recvpipe,
hc_entry->rmx_hits,
hc_entry->rmx_updates,
hc_entry->rmx_expire);
p += len;
}
THC_UNLOCK(&tcp_hostcache.hashbase[i].hch_mtx);
}
#undef msec
error = SYSCTL_OUT(req, buf, p - buf);
free(buf, M_TEMP);
return(error);
}
/*
* Expire and purge (old|all) entries in the tcp_hostcache. Runs periodically
* from the callout.
*/
static void
tcp_hc_purge(void *arg)
{
struct hc_metrics *hc_entry, *hc_next;
int all = (intptr_t)arg;
int i;
if (tcp_hostcache.purgeall) {
all = 1;
tcp_hostcache.purgeall = 0;
}
for (i = 0; i < tcp_hostcache.hashsize; i++) {
THC_LOCK(&tcp_hostcache.hashbase[i].hch_mtx);
TAILQ_FOREACH_SAFE(hc_entry, &tcp_hostcache.hashbase[i].hch_bucket,
rmx_q, hc_next) {
if (all || hc_entry->rmx_expire <= 0) {
TAILQ_REMOVE(&tcp_hostcache.hashbase[i].hch_bucket,
hc_entry, rmx_q);
uma_zfree(tcp_hostcache.zone, hc_entry);
tcp_hostcache.hashbase[i].hch_length--;
tcp_hostcache.cache_count--;
} else
hc_entry->rmx_expire -= TCP_HOSTCACHE_PRUNE;
}
THC_UNLOCK(&tcp_hostcache.hashbase[i].hch_mtx);
}
callout_reset(&tcp_hc_callout, TCP_HOSTCACHE_PRUNE * hz, tcp_hc_purge, 0);
}
