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/*-
* 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: release/9.1.0/sys/netinet/tcp_hostcache.c 238259 2012-07-08 19:29:08Z trociny $");
#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 <net/route.h>
#include <net/vnet.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>
#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 */
static VNET_DEFINE(struct tcp_hostcache, tcp_hostcache);
#define V_tcp_hostcache VNET(tcp_hostcache)
static VNET_DEFINE(struct callout, tcp_hc_callout);
#define V_tcp_hc_callout VNET(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_internal(int);
static void tcp_hc_purge(void *);
SYSCTL_NODE(_net_inet_tcp, OID_AUTO, hostcache, CTLFLAG_RW, 0,
"TCP Host cache");
SYSCTL_VNET_UINT(_net_inet_tcp_hostcache, OID_AUTO, cachelimit, CTLFLAG_RDTUN,
&VNET_NAME(tcp_hostcache.cache_limit), 0,
"Overall entry limit for hostcache");
SYSCTL_VNET_UINT(_net_inet_tcp_hostcache, OID_AUTO, hashsize, CTLFLAG_RDTUN,
&VNET_NAME(tcp_hostcache.hashsize), 0,
"Size of TCP hostcache hashtable");
SYSCTL_VNET_UINT(_net_inet_tcp_hostcache, OID_AUTO, bucketlimit,
CTLFLAG_RDTUN, &VNET_NAME(tcp_hostcache.bucket_limit), 0,
"Per-bucket hash limit for hostcache");
SYSCTL_VNET_UINT(_net_inet_tcp_hostcache, OID_AUTO, count, CTLFLAG_RD,
&VNET_NAME(tcp_hostcache.cache_count), 0,
"Current number of entries in hostcache");
SYSCTL_VNET_INT(_net_inet_tcp_hostcache, OID_AUTO, expire, CTLFLAG_RW,
&VNET_NAME(tcp_hostcache.expire), 0,
"Expire time of TCP hostcache entries");
SYSCTL_VNET_INT(_net_inet_tcp_hostcache, OID_AUTO, prune, CTLFLAG_RW,
&VNET_NAME(tcp_hostcache.prune), 0,
"Time between purge runs");
SYSCTL_VNET_INT(_net_inet_tcp_hostcache, OID_AUTO, purge, CTLFLAG_RW,
&VNET_NAME(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)
{
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, curvnet);
}
#ifdef VIMAGE
void
tcp_hc_destroy(void)
{
int i;
callout_drain(&V_tcp_hc_callout);
/* Purge all hc entries. */
tcp_hc_purge_internal(1);
/* Free the uma zone and the allocated hash table. */
uma_zdestroy(V_tcp_hostcache.zone);
for (i = 0; i < V_tcp_hostcache.hashsize; i++)
mtx_destroy(&V_tcp_hostcache.hashbase[i].hch_mtx);
free(V_tcp_hostcache.hashbase, M_HOSTCACHE);
}
#endif
/*
* 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)
{
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_flags & 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_flags & 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_flags & 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--;
TCPSTAT_INC(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_flags & 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++;
TCPSTAT_INC(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)
{
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)
{
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)
{
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)
{
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;
TCPSTAT_INC(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_INC(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_INC(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_INC(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_INC(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_INC(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_INC(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;
#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_RTTVAR_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);
}
/*
* Caller has to make sure the curvnet is set properly.
*/
static void
tcp_hc_purge_internal(int all)
{
struct hc_metrics *hc_entry, *hc_next;
int i;
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);
}
}
/*
* Expire and purge (old|all) entries in the tcp_hostcache. Runs
* periodically from the callout.
*/
static void
tcp_hc_purge(void *arg)
{
CURVNET_SET((struct vnet *) arg);
int all = 0;
if (V_tcp_hostcache.purgeall) {
all = 1;
V_tcp_hostcache.purgeall = 0;
}
tcp_hc_purge_internal(all);
callout_reset(&V_tcp_hc_callout, V_tcp_hostcache.prune * hz,
tcp_hc_purge, arg);
CURVNET_RESTORE();
}