freebsd-dev/sys/netinet/tcp_hostcache.c
Bjoern A. Zeeb 4b79449e2f Rather than using hidden includes (with cicular dependencies),
directly include only the header files needed. This reduces the
unneeded spamming of various headers into lots of files.

For now, this leaves us with very few modules including vnet.h
and thus needing to depend on opt_route.h.

Reviewed by:	brooks, gnn, des, zec, imp
Sponsored by:	The FreeBSD Foundation
2008-12-02 21:37:28 +00:00

666 lines
20 KiB
C

/*-
* 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.
*/
/*
* The tcp_hostcache moves the tcp-specific cached metrics from the routing
* table to a dedicated structure indexed by the remote IP address. It keeps
* information on the measured TCP parameters of past TCP sessions to allow
* better initial start values to be used with later connections to/from the
* same source. Depending on the network parameters (delay, bandwidth, max
* MTU, congestion window) between local and remote sites, this can lead to
* significant speed-ups for new TCP connections after the first one.
*
* Due to the tcp_hostcache, all TCP-specific metrics information in the
* routing table have 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 outside of tcp_hostcache.c will ever point directly to any
* entry in the tcp_hostcache. All communication is done in an
* object-oriented way and only functions 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 <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#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 <sys/vimage.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>
#include <netinet/tcp_hostcache.h>
#include <netinet/vinet.h>
#ifdef INET6
#include <netinet6/tcp6_var.h>
#endif
#include <vm/uma.h>
/* 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 */
#ifdef VIMAGE_GLOBALS
static struct tcp_hostcache tcp_hostcache;
static struct callout tcp_hc_callout;
#endif
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_V_INT(V_NET, vnet_inet, _net_inet_tcp_hostcache, OID_AUTO, cachelimit,
CTLFLAG_RDTUN, tcp_hostcache.cache_limit, 0,
"Overall entry limit for hostcache");
SYSCTL_V_INT(V_NET, vnet_inet, _net_inet_tcp_hostcache, OID_AUTO, hashsize,
CTLFLAG_RDTUN, tcp_hostcache.hashsize, 0,
"Size of TCP hostcache hashtable");
SYSCTL_V_INT(V_NET, vnet_inet, _net_inet_tcp_hostcache, OID_AUTO, bucketlimit,
CTLFLAG_RDTUN, tcp_hostcache.bucket_limit, 0,
"Per-bucket hash limit for hostcache");
SYSCTL_V_INT(V_NET, vnet_inet, _net_inet_tcp_hostcache, OID_AUTO, count,
CTLFLAG_RD, tcp_hostcache.cache_count, 0,
"Current number of entries in hostcache");
SYSCTL_V_INT(V_NET, vnet_inet, _net_inet_tcp_hostcache, OID_AUTO, expire,
CTLFLAG_RW, tcp_hostcache.expire, 0,
"Expire time of TCP hostcache entries");
SYSCTL_V_INT(V_NET, vnet_inet, _net_inet_tcp_hostcache, OID_AUTO, prune,
CTLFLAG_RW, tcp_hostcache.prune, 0, "Time between purge runs");
SYSCTL_V_INT(V_NET, vnet_inet, _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)) & \
V_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]) & \
V_tcp_hostcache.hashmask)
#define THC_LOCK(lp) mtx_lock(lp)
#define THC_UNLOCK(lp) mtx_unlock(lp)
void
tcp_hc_init(void)
{
INIT_VNET_INET(curvnet);
int i;
/*
* Initialize hostcache structures.
*/
V_tcp_hostcache.cache_count = 0;
V_tcp_hostcache.hashsize = TCP_HOSTCACHE_HASHSIZE;
V_tcp_hostcache.bucket_limit = TCP_HOSTCACHE_BUCKETLIMIT;
V_tcp_hostcache.cache_limit =
V_tcp_hostcache.hashsize * V_tcp_hostcache.bucket_limit;
V_tcp_hostcache.expire = TCP_HOSTCACHE_EXPIRE;
V_tcp_hostcache.prune = TCP_HOSTCACHE_PRUNE;
TUNABLE_INT_FETCH("net.inet.tcp.hostcache.hashsize",
&V_tcp_hostcache.hashsize);
TUNABLE_INT_FETCH("net.inet.tcp.hostcache.cachelimit",
&V_tcp_hostcache.cache_limit);
TUNABLE_INT_FETCH("net.inet.tcp.hostcache.bucketlimit",
&V_tcp_hostcache.bucket_limit);
if (!powerof2(V_tcp_hostcache.hashsize)) {
printf("WARNING: hostcache hash size is not a power of 2.\n");
V_tcp_hostcache.hashsize = TCP_HOSTCACHE_HASHSIZE; /* default */
}
V_tcp_hostcache.hashmask = V_tcp_hostcache.hashsize - 1;
/*
* Allocate the hash table.
*/
V_tcp_hostcache.hashbase = (struct hc_head *)
malloc(V_tcp_hostcache.hashsize * sizeof(struct hc_head),
M_HOSTCACHE, M_WAITOK | M_ZERO);
/*
* Initialize the hash buckets.
*/
for (i = 0; i < V_tcp_hostcache.hashsize; i++) {
TAILQ_INIT(&V_tcp_hostcache.hashbase[i].hch_bucket);
V_tcp_hostcache.hashbase[i].hch_length = 0;
mtx_init(&V_tcp_hostcache.hashbase[i].hch_mtx, "tcp_hc_entry",
NULL, MTX_DEF);
}
/*
* Allocate the hostcache entries.
*/
V_tcp_hostcache.zone =
uma_zcreate("hostcache", sizeof(struct hc_metrics),
NULL, NULL, NULL, NULL, UMA_ALIGN_PTR, 0);
uma_zone_set_max(V_tcp_hostcache.zone, V_tcp_hostcache.cache_limit);
/*
* Set up periodic cache cleanup.
*/
callout_init(&V_tcp_hc_callout, CALLOUT_MPSAFE);
callout_reset(&V_tcp_hc_callout, V_tcp_hostcache.prune * hz,
tcp_hc_purge, 0);
}
/*
* Internal function: look up 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)
{
INIT_VNET_INET(curvnet);
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 = &V_tcp_hostcache.hashbase[hash];
/*
* Acquire 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);
/*
* Iterate 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)
{
INIT_VNET_INET(curvnet);
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 = &V_tcp_hostcache.hashbase[hash];
/*
* Acquire 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 >= V_tcp_hostcache.bucket_limit ||
V_tcp_hostcache.cache_count >= V_tcp_hostcache.cache_limit) {
hc_entry = TAILQ_LAST(&hc_head->hch_bucket, hc_qhead);
/*
* At first we were dropping the last element, just to
* reacquire it in the next two lines again, which isn't very
* efficient. Instead just reuse the least used element.
* We may drop something that is still "in-use" but we can be
* "lossy".
* Just give up if this bucket row is empty and we don't have
* anything to replace.
*/
if (hc_entry == NULL) {
THC_UNLOCK(&hc_head->hch_mtx);
return NULL;
}
TAILQ_REMOVE(&hc_head->hch_bucket, hc_entry, rmx_q);
V_tcp_hostcache.hashbase[hash].hch_length--;
V_tcp_hostcache.cache_count--;
V_tcpstat.tcps_hc_bucketoverflow++;
#if 0
uma_zfree(V_tcp_hostcache.zone, hc_entry);
#endif
} else {
/*
* Allocate a new entry, or balk if not possible.
*/
hc_entry = uma_zalloc(V_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 = V_tcp_hostcache.expire;
/*
* Put it upfront.
*/
TAILQ_INSERT_HEAD(&hc_head->hch_bucket, hc_entry, rmx_q);
V_tcp_hostcache.hashbase[hash].hch_length++;
V_tcp_hostcache.cache_count++;
V_tcpstat.tcps_hc_added++;
return hc_entry;
}
/*
* External function: look up 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)
{
INIT_VNET_INET(curvnet);
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 = V_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: look up 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)
{
INIT_VNET_INET(curvnet);
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 = V_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)
{
INIT_VNET_INET(curvnet);
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 = V_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)
{
INIT_VNET_INET(curvnet);
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 = V_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;
V_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;
V_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;
V_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;
/* V_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;
/* V_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;
/* V_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;
/* V_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)
{
INIT_VNET_INET(curvnet);
int bufsize;
int linesize = 128;
char *p, *buf;
int len, i, error;
struct hc_metrics *hc_entry;
#ifdef INET6
char ip6buf[INET6_ADDRSTRLEN];
#endif
bufsize = linesize * (V_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 < V_tcp_hostcache.hashsize; i++) {
THC_LOCK(&V_tcp_hostcache.hashbase[i].hch_mtx);
TAILQ_FOREACH(hc_entry, &V_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(ip6buf, &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(&V_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)
{
INIT_VNET_INET(curvnet);
struct hc_metrics *hc_entry, *hc_next;
int all = (intptr_t)arg;
int i;
if (V_tcp_hostcache.purgeall) {
all = 1;
V_tcp_hostcache.purgeall = 0;
}
for (i = 0; i < V_tcp_hostcache.hashsize; i++) {
THC_LOCK(&V_tcp_hostcache.hashbase[i].hch_mtx);
TAILQ_FOREACH_SAFE(hc_entry,
&V_tcp_hostcache.hashbase[i].hch_bucket, rmx_q, hc_next) {
if (all || hc_entry->rmx_expire <= 0) {
TAILQ_REMOVE(&V_tcp_hostcache.hashbase[i].hch_bucket,
hc_entry, rmx_q);
uma_zfree(V_tcp_hostcache.zone, hc_entry);
V_tcp_hostcache.hashbase[i].hch_length--;
V_tcp_hostcache.cache_count--;
} else
hc_entry->rmx_expire -= V_tcp_hostcache.prune;
}
THC_UNLOCK(&V_tcp_hostcache.hashbase[i].hch_mtx);
}
callout_reset(&V_tcp_hc_callout, V_tcp_hostcache.prune * hz,
tcp_hc_purge, arg);
}