/*-
* SPDX-License-Identifier: BSD-3-Clause
*
* Copyright (c) 2002 Andre Oppermann, Internet Business Solutions AG
* Copyright (c) 2021 Gleb Smirnoff <glebius@FreeBSD.org>
* 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, 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. It is a straight hash. Each bucket row
* is protected by its own lock for modification. Readers are protected by
* SMR. This puts certain restrictions on writers, e.g. a writer shall only
* insert a fully populated entry into a row. Writer can't reuse least used
* entry if a hash is full. Value updates for an entry shall be atomic.
*
* TCP stack(s) communication with tcp_hostcache() is done via KBI functions
* tcp_hc_*() and the hc_metrics_lite structure.
*
* Since tcp_hostcache is only caching information, there are no fatal
* consequences if we either can't allocate a new entry or have to drop
* an existing entry, or return somewhat stale information.
*/
/*
* 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/hash.h>
#include <sys/jail.h>
#include <sys/kernel.h>
#include <sys/lock.h>
#include <sys/mutex.h>
#include <sys/malloc.h>
#include <sys/proc.h>
#include <sys/sbuf.h>
#include <sys/smr.h>
#include <sys/socket.h>
#include <sys/socketvar.h>
#include <sys/sysctl.h>
#include <net/vnet.h>
#include <netinet/in.h>
#include <netinet/in_pcb.h>
#include <netinet/tcp.h>
#include <netinet/tcp_var.h>
#include <vm/uma.h>
struct hc_head {
CK_SLIST_HEAD(hc_qhead, hc_metrics) hch_bucket;
u_int hch_length;
struct mtx hch_mtx;
};
struct hc_metrics {
/* housekeeping */
CK_SLIST_ENTRY(hc_metrics) rmx_q;
struct in_addr ip4; /* IP address */
struct in6_addr ip6; /* IP6 address */
uint32_t ip6_zoneid; /* IPv6 scope zone id */
/* endpoint specific values for tcp */
uint32_t rmx_mtu; /* MTU for this path */
uint32_t rmx_ssthresh; /* outbound gateway buffer limit */
uint32_t rmx_rtt; /* estimated round trip time */
uint32_t rmx_rttvar; /* estimated rtt variance */
uint32_t rmx_cwnd; /* congestion window */
uint32_t rmx_sendpipe; /* outbound delay-bandwidth product */
uint32_t rmx_recvpipe; /* inbound delay-bandwidth product */
/* TCP hostcache internal data */
int rmx_expire; /* lifetime for object */
#ifdef TCP_HC_COUNTERS
u_long rmx_hits; /* number of hits */
u_long rmx_updates; /* number of updates */
#endif
};
struct tcp_hostcache {
struct hc_head *hashbase;
uma_zone_t zone;
smr_t smr;
u_int hashsize;
u_int hashmask;
u_int hashsalt;
u_int bucket_limit;
u_int cache_count;
u_int cache_limit;
int expire;
int prune;
int purgeall;
};
/* 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 */
VNET_DEFINE_STATIC(struct tcp_hostcache, tcp_hostcache);
#define V_tcp_hostcache VNET(tcp_hostcache)
VNET_DEFINE_STATIC(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 int sysctl_tcp_hc_list(SYSCTL_HANDLER_ARGS);
static int sysctl_tcp_hc_histo(SYSCTL_HANDLER_ARGS);
static int sysctl_tcp_hc_purgenow(SYSCTL_HANDLER_ARGS);
static void tcp_hc_purge_internal(int);
static void tcp_hc_purge(void *);
static SYSCTL_NODE(_net_inet_tcp, OID_AUTO, hostcache,
CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
"TCP Host cache");
VNET_DEFINE(int, tcp_use_hostcache) = 1;
#define V_tcp_use_hostcache VNET(tcp_use_hostcache)
SYSCTL_INT(_net_inet_tcp_hostcache, OID_AUTO, enable, CTLFLAG_VNET | CTLFLAG_RW,
&VNET_NAME(tcp_use_hostcache), 0,
"Enable the TCP hostcache");
SYSCTL_UINT(_net_inet_tcp_hostcache, OID_AUTO, cachelimit, CTLFLAG_VNET | CTLFLAG_RDTUN,
&VNET_NAME(tcp_hostcache.cache_limit), 0,
"Overall entry limit for hostcache");
SYSCTL_UINT(_net_inet_tcp_hostcache, OID_AUTO, hashsize, CTLFLAG_VNET | CTLFLAG_RDTUN,
&VNET_NAME(tcp_hostcache.hashsize), 0,
"Size of TCP hostcache hashtable");
SYSCTL_UINT(_net_inet_tcp_hostcache, OID_AUTO, bucketlimit,
CTLFLAG_VNET | CTLFLAG_RDTUN, &VNET_NAME(tcp_hostcache.bucket_limit), 0,
"Per-bucket hash limit for hostcache");
SYSCTL_UINT(_net_inet_tcp_hostcache, OID_AUTO, count, CTLFLAG_VNET | CTLFLAG_RD,
&VNET_NAME(tcp_hostcache.cache_count), 0,
"Current number of entries in hostcache");
SYSCTL_INT(_net_inet_tcp_hostcache, OID_AUTO, expire, CTLFLAG_VNET | CTLFLAG_RW,
&VNET_NAME(tcp_hostcache.expire), 0,
"Expire time of TCP hostcache entries");
SYSCTL_INT(_net_inet_tcp_hostcache, OID_AUTO, prune, CTLFLAG_VNET | CTLFLAG_RW,
&VNET_NAME(tcp_hostcache.prune), 0,
"Time between purge runs");
SYSCTL_INT(_net_inet_tcp_hostcache, OID_AUTO, purge, CTLFLAG_VNET | 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 | CTLFLAG_MPSAFE,
0, 0, sysctl_tcp_hc_list, "A",
"List of all hostcache entries");
SYSCTL_PROC(_net_inet_tcp_hostcache, OID_AUTO, histo,
CTLTYPE_STRING | CTLFLAG_RD | CTLFLAG_SKIP | CTLFLAG_MPSAFE,
0, 0, sysctl_tcp_hc_histo, "A",
"Print a histogram of hostcache hashbucket utilization");
SYSCTL_PROC(_net_inet_tcp_hostcache, OID_AUTO, purgenow,
CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_MPSAFE,
NULL, 0, sysctl_tcp_hc_purgenow, "I",
"Immediately purge all entries");
static MALLOC_DEFINE(M_HOSTCACHE, "hostcache", "TCP hostcache");
/* Use jenkins_hash32(), as in other parts of the tcp stack */
#define HOSTCACHE_HASH(inc) \
((inc)->inc_flags & INC_ISIPV6) ? \
(jenkins_hash32((inc)->inc6_faddr.s6_addr32, 4, \
V_tcp_hostcache.hashsalt) & V_tcp_hostcache.hashmask) \
: \
(jenkins_hash32(&(inc)->inc_faddr.s_addr, 1, \
V_tcp_hostcache.hashsalt) & V_tcp_hostcache.hashmask)
#define THC_LOCK(h) mtx_lock(&(h)->hch_mtx)
#define THC_UNLOCK(h) mtx_unlock(&(h)->hch_mtx)
void
tcp_hc_init(void)
{
u_int cache_limit;
int i;
/*
* Initialize hostcache structures.
*/
atomic_store_int(&V_tcp_hostcache.cache_count, 0);
V_tcp_hostcache.hashsize = TCP_HOSTCACHE_HASHSIZE;
V_tcp_hostcache.bucket_limit = TCP_HOSTCACHE_BUCKETLIMIT;
V_tcp_hostcache.expire = TCP_HOSTCACHE_EXPIRE;
V_tcp_hostcache.prune = TCP_HOSTCACHE_PRUNE;
V_tcp_hostcache.hashsalt = arc4random();
TUNABLE_INT_FETCH("net.inet.tcp.hostcache.hashsize",
&V_tcp_hostcache.hashsize);
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;
TUNABLE_INT_FETCH("net.inet.tcp.hostcache.bucketlimit",
&V_tcp_hostcache.bucket_limit);
cache_limit = V_tcp_hostcache.hashsize * V_tcp_hostcache.bucket_limit;
V_tcp_hostcache.cache_limit = cache_limit;
TUNABLE_INT_FETCH("net.inet.tcp.hostcache.cachelimit",
&V_tcp_hostcache.cache_limit);
if (V_tcp_hostcache.cache_limit > cache_limit)
V_tcp_hostcache.cache_limit = cache_limit;
/*
* 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++) {
CK_SLIST_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, UMA_ZONE_SMR);
uma_zone_set_max(V_tcp_hostcache.zone, V_tcp_hostcache.cache_limit);
V_tcp_hostcache.smr = uma_zone_get_smr(V_tcp_hostcache.zone);
/*
* Set up periodic cache cleanup.
*/
callout_init(&V_tcp_hc_callout, 1);
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: compare cache entry to a connection.
*/
static bool
tcp_hc_cmp(struct hc_metrics *hc_entry, struct in_conninfo *inc)
{
if (inc->inc_flags & INC_ISIPV6) {
/* XXX: check ip6_zoneid */
if (memcmp(&inc->inc6_faddr, &hc_entry->ip6,
sizeof(inc->inc6_faddr)) == 0)
return (true);
} else {
if (memcmp(&inc->inc_faddr, &hc_entry->ip4,
sizeof(inc->inc_faddr)) == 0)
return (true);
}
return (false);
}
/*
* Internal function: look up an entry in the hostcache for read.
* On success returns in SMR section.
*/
static struct hc_metrics *
tcp_hc_lookup(struct in_conninfo *inc)
{
struct hc_head *hc_head;
struct hc_metrics *hc_entry;
KASSERT(inc != NULL, ("%s: NULL in_conninfo", __func__));
hc_head = &V_tcp_hostcache.hashbase[HOSTCACHE_HASH(inc)];
/*
* Iterate through entries in bucket row looking for a match.
*/
smr_enter(V_tcp_hostcache.smr);
CK_SLIST_FOREACH(hc_entry, &hc_head->hch_bucket, rmx_q)
if (tcp_hc_cmp(hc_entry, inc))
break;
if (hc_entry != NULL) {
if (atomic_load_int(&hc_entry->rmx_expire) !=
V_tcp_hostcache.expire)
atomic_store_int(&hc_entry->rmx_expire,
V_tcp_hostcache.expire);
#ifdef TCP_HC_COUNTERS
hc_entry->rmx_hits++;
#endif
} else
smr_exit(V_tcp_hostcache.smr);
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;
if (!V_tcp_use_hostcache) {
bzero(hc_metrics_lite, sizeof(*hc_metrics_lite));
return;
}
/*
* 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_metrics_lite->rmx_mtu = atomic_load_32(&hc_entry->rmx_mtu);
hc_metrics_lite->rmx_ssthresh = atomic_load_32(&hc_entry->rmx_ssthresh);
hc_metrics_lite->rmx_rtt = atomic_load_32(&hc_entry->rmx_rtt);
hc_metrics_lite->rmx_rttvar = atomic_load_32(&hc_entry->rmx_rttvar);
hc_metrics_lite->rmx_cwnd = atomic_load_32(&hc_entry->rmx_cwnd);
hc_metrics_lite->rmx_sendpipe = atomic_load_32(&hc_entry->rmx_sendpipe);
hc_metrics_lite->rmx_recvpipe = atomic_load_32(&hc_entry->rmx_recvpipe);
smr_exit(V_tcp_hostcache.smr);
}
/*
* External function: look up an entry in the hostcache and return the
* discovered path MTU. Returns 0 if no entry is found or value is not
* set.
*/
uint32_t
tcp_hc_getmtu(struct in_conninfo *inc)
{
struct hc_metrics *hc_entry;
uint32_t mtu;
if (!V_tcp_use_hostcache)
return (0);
hc_entry = tcp_hc_lookup(inc);
if (hc_entry == NULL) {
return (0);
}
mtu = atomic_load_32(&hc_entry->rmx_mtu);
smr_exit(V_tcp_hostcache.smr);
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, uint32_t mtu)
{
struct hc_metrics_lite hcml = { .rmx_mtu = mtu };
return (tcp_hc_update(inc, &hcml));
}
/*
* 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_head *hc_head;
struct hc_metrics *hc_entry, *hc_prev;
uint32_t v;
bool new;
if (!V_tcp_use_hostcache)
return;
hc_head = &V_tcp_hostcache.hashbase[HOSTCACHE_HASH(inc)];
hc_prev = NULL;
THC_LOCK(hc_head);
CK_SLIST_FOREACH(hc_entry, &hc_head->hch_bucket, rmx_q) {
if (tcp_hc_cmp(hc_entry, inc))
break;
if (CK_SLIST_NEXT(hc_entry, rmx_q) != NULL)
hc_prev = hc_entry;
}
if (hc_entry != NULL) {
if (atomic_load_int(&hc_entry->rmx_expire) !=
V_tcp_hostcache.expire)
atomic_store_int(&hc_entry->rmx_expire,
V_tcp_hostcache.expire);
#ifdef TCP_HC_COUNTERS
hc_entry->rmx_updates++;
#endif
new = false;
} else {
/*
* Try to allocate a new entry. If the bucket limit is
* reached, delete the least-used element, located at the end
* of the CK_SLIST. During lookup we saved the pointer to
* the second to last element, in case if list has at least 2
* elements. This will allow to delete last element without
* extra traversal.
*
* Give up if the row is empty.
*/
if (hc_head->hch_length >= V_tcp_hostcache.bucket_limit ||
atomic_load_int(&V_tcp_hostcache.cache_count) >=
V_tcp_hostcache.cache_limit) {
if (hc_prev != NULL) {
hc_entry = CK_SLIST_NEXT(hc_prev, rmx_q);
KASSERT(CK_SLIST_NEXT(hc_entry, rmx_q) == NULL,
("%s: %p is not one to last",
__func__, hc_prev));
CK_SLIST_REMOVE_AFTER(hc_prev, rmx_q);
} else if ((hc_entry =
CK_SLIST_FIRST(&hc_head->hch_bucket)) != NULL) {
KASSERT(CK_SLIST_NEXT(hc_entry, rmx_q) == NULL,
("%s: %p is not the only element",
__func__, hc_entry));
CK_SLIST_REMOVE_HEAD(&hc_head->hch_bucket,
rmx_q);
} else {
THC_UNLOCK(hc_head);
return;
}
KASSERT(hc_head->hch_length > 0 &&
hc_head->hch_length <= V_tcp_hostcache.bucket_limit,
("tcp_hostcache: bucket length violated at %p",
hc_head));
hc_head->hch_length--;
atomic_subtract_int(&V_tcp_hostcache.cache_count, 1);
TCPSTAT_INC(tcps_hc_bucketoverflow);
uma_zfree_smr(V_tcp_hostcache.zone, hc_entry);
}
/*
* Allocate a new entry, or balk if not possible.
*/
hc_entry = uma_zalloc_smr(V_tcp_hostcache.zone, M_NOWAIT);
if (hc_entry == NULL) {
THC_UNLOCK(hc_head);
return;
}
/*
* Initialize basic information of hostcache entry.
*/
bzero(hc_entry, sizeof(*hc_entry));
if (inc->inc_flags & INC_ISIPV6) {
hc_entry->ip6 = inc->inc6_faddr;
hc_entry->ip6_zoneid = inc->inc6_zoneid;
} else
hc_entry->ip4 = inc->inc_faddr;
hc_entry->rmx_expire = V_tcp_hostcache.expire;
new = true;
}
/*
* Fill in data. Use atomics, since an existing entry is
* accessible by readers in SMR section.
*/
if (hcml->rmx_mtu != 0) {
atomic_store_32(&hc_entry->rmx_mtu, hcml->rmx_mtu);
}
if (hcml->rmx_rtt != 0) {
if (hc_entry->rmx_rtt == 0)
v = hcml->rmx_rtt;
else
v = ((uint64_t)hc_entry->rmx_rtt +
(uint64_t)hcml->rmx_rtt) / 2;
atomic_store_32(&hc_entry->rmx_rtt, v);
TCPSTAT_INC(tcps_cachedrtt);
}
if (hcml->rmx_rttvar != 0) {
if (hc_entry->rmx_rttvar == 0)
v = hcml->rmx_rttvar;
else
v = ((uint64_t)hc_entry->rmx_rttvar +
(uint64_t)hcml->rmx_rttvar) / 2;
atomic_store_32(&hc_entry->rmx_rttvar, v);
TCPSTAT_INC(tcps_cachedrttvar);
}
if (hcml->rmx_ssthresh != 0) {
if (hc_entry->rmx_ssthresh == 0)
v = hcml->rmx_ssthresh;
else
v = (hc_entry->rmx_ssthresh + hcml->rmx_ssthresh) / 2;
atomic_store_32(&hc_entry->rmx_ssthresh, v);
TCPSTAT_INC(tcps_cachedssthresh);
}
if (hcml->rmx_cwnd != 0) {
if (hc_entry->rmx_cwnd == 0)
v = hcml->rmx_cwnd;
else
v = ((uint64_t)hc_entry->rmx_cwnd +
(uint64_t)hcml->rmx_cwnd) / 2;
atomic_store_32(&hc_entry->rmx_cwnd, v);
/* TCPSTAT_INC(tcps_cachedcwnd); */
}
if (hcml->rmx_sendpipe != 0) {
if (hc_entry->rmx_sendpipe == 0)
v = hcml->rmx_sendpipe;
else
v = ((uint64_t)hc_entry->rmx_sendpipe +
(uint64_t)hcml->rmx_sendpipe) /2;
atomic_store_32(&hc_entry->rmx_sendpipe, v);
/* TCPSTAT_INC(tcps_cachedsendpipe); */
}
if (hcml->rmx_recvpipe != 0) {
if (hc_entry->rmx_recvpipe == 0)
v = hcml->rmx_recvpipe;
else
v = ((uint64_t)hc_entry->rmx_recvpipe +
(uint64_t)hcml->rmx_recvpipe) /2;
atomic_store_32(&hc_entry->rmx_recvpipe, v);
/* TCPSTAT_INC(tcps_cachedrecvpipe); */
}
/*
* Put it upfront.
*/
if (new) {
CK_SLIST_INSERT_HEAD(&hc_head->hch_bucket, hc_entry, rmx_q);
hc_head->hch_length++;
KASSERT(hc_head->hch_length <= V_tcp_hostcache.bucket_limit,
("tcp_hostcache: bucket length too high at %p", hc_head));
atomic_add_int(&V_tcp_hostcache.cache_count, 1);
TCPSTAT_INC(tcps_hc_added);
} else if (hc_entry != CK_SLIST_FIRST(&hc_head->hch_bucket)) {
KASSERT(CK_SLIST_NEXT(hc_prev, rmx_q) == hc_entry,
("%s: %p next is not %p", __func__, hc_prev, hc_entry));
CK_SLIST_REMOVE_AFTER(hc_prev, rmx_q);
CK_SLIST_INSERT_HEAD(&hc_head->hch_bucket, hc_entry, rmx_q);
}
THC_UNLOCK(hc_head);
}
/*
* Sysctl function: prints the list and values of all hostcache entries in
* unsorted order.
*/
static int
sysctl_tcp_hc_list(SYSCTL_HANDLER_ARGS)
{
const int linesize = 128;
struct sbuf sb;
int i, error, len;
struct hc_metrics *hc_entry;
char ip4buf[INET_ADDRSTRLEN];
#ifdef INET6
char ip6buf[INET6_ADDRSTRLEN];
#endif
if (jailed_without_vnet(curthread->td_ucred) != 0)
return (EPERM);
/* Optimize Buffer length query by sbin/sysctl */
if (req->oldptr == NULL) {
len = (atomic_load_int(&V_tcp_hostcache.cache_count) + 1) *
linesize;
return (SYSCTL_OUT(req, NULL, len));
}
error = sysctl_wire_old_buffer(req, 0);
if (error != 0) {
return(error);
}
/* Use a buffer sized for one full bucket */
sbuf_new_for_sysctl(&sb, NULL, V_tcp_hostcache.bucket_limit *
linesize, req);
sbuf_printf(&sb,
"\nIP address MTU SSTRESH RTT RTTVAR "
" CWND SENDPIPE RECVPIPE "
#ifdef TCP_HC_COUNTERS
"HITS UPD "
#endif
"EXP\n");
sbuf_drain(&sb);
#define msec(u) (((u) + 500) / 1000)
for (i = 0; i < V_tcp_hostcache.hashsize; i++) {
THC_LOCK(&V_tcp_hostcache.hashbase[i]);
CK_SLIST_FOREACH(hc_entry,
&V_tcp_hostcache.hashbase[i].hch_bucket, rmx_q) {
sbuf_printf(&sb,
"%-15s %5u %8u %6lums %6lums %8u %8u %8u "
#ifdef TCP_HC_COUNTERS
"%4lu %4lu "
#endif
"%4i\n",
hc_entry->ip4.s_addr ?
inet_ntoa_r(hc_entry->ip4, ip4buf) :
#ifdef INET6
ip6_sprintf(ip6buf, &hc_entry->ip6),
#else
"IPv6?",
#endif
hc_entry->rmx_mtu,
hc_entry->rmx_ssthresh,
msec((u_long)hc_entry->rmx_rtt *
(RTM_RTTUNIT / (hz * TCP_RTT_SCALE))),
msec((u_long)hc_entry->rmx_rttvar *
(RTM_RTTUNIT / (hz * TCP_RTTVAR_SCALE))),
hc_entry->rmx_cwnd,
hc_entry->rmx_sendpipe,
hc_entry->rmx_recvpipe,
#ifdef TCP_HC_COUNTERS
hc_entry->rmx_hits,
hc_entry->rmx_updates,
#endif
hc_entry->rmx_expire);
}
THC_UNLOCK(&V_tcp_hostcache.hashbase[i]);
sbuf_drain(&sb);
}
#undef msec
error = sbuf_finish(&sb);
sbuf_delete(&sb);
return(error);
}
/*
* Sysctl function: prints a histogram of the hostcache hashbucket
* utilization.
*/
static int
sysctl_tcp_hc_histo(SYSCTL_HANDLER_ARGS)
{
const int linesize = 50;
struct sbuf sb;
int i, error;
int *histo;
u_int hch_length;
if (jailed_without_vnet(curthread->td_ucred) != 0)
return (EPERM);
histo = (int *)malloc(sizeof(int) * (V_tcp_hostcache.bucket_limit + 1),
M_TEMP, M_NOWAIT|M_ZERO);
if (histo == NULL)
return(ENOMEM);
for (i = 0; i < V_tcp_hostcache.hashsize; i++) {
hch_length = V_tcp_hostcache.hashbase[i].hch_length;
KASSERT(hch_length <= V_tcp_hostcache.bucket_limit,
("tcp_hostcache: bucket limit exceeded at %u: %u",
i, hch_length));
histo[hch_length]++;
}
/* Use a buffer for 16 lines */
sbuf_new_for_sysctl(&sb, NULL, 16 * linesize, req);
sbuf_printf(&sb, "\nLength\tCount\n");
for (i = 0; i <= V_tcp_hostcache.bucket_limit; i++) {
sbuf_printf(&sb, "%u\t%u\n", i, histo[i]);
}
error = sbuf_finish(&sb);
sbuf_delete(&sb);
free(histo, M_TEMP);
return(error);
}
/*
* Caller has to make sure the curvnet is set properly.
*/
static void
tcp_hc_purge_internal(int all)
{
struct hc_head *head;
struct hc_metrics *hc_entry, *hc_next, *hc_prev;
int i;
for (i = 0; i < V_tcp_hostcache.hashsize; i++) {
head = &V_tcp_hostcache.hashbase[i];
hc_prev = NULL;
THC_LOCK(head);
CK_SLIST_FOREACH_SAFE(hc_entry, &head->hch_bucket, rmx_q,
hc_next) {
KASSERT(head->hch_length > 0 && head->hch_length <=
V_tcp_hostcache.bucket_limit, ("tcp_hostcache: "
"bucket length out of range at %u: %u", i,
head->hch_length));
if (all ||
atomic_load_int(&hc_entry->rmx_expire) <= 0) {
if (hc_prev != NULL) {
KASSERT(hc_entry ==
CK_SLIST_NEXT(hc_prev, rmx_q),
("%s: %p is not next to %p",
__func__, hc_entry, hc_prev));
CK_SLIST_REMOVE_AFTER(hc_prev, rmx_q);
} else {
KASSERT(hc_entry ==
CK_SLIST_FIRST(&head->hch_bucket),
("%s: %p is not first",
__func__, hc_entry));
CK_SLIST_REMOVE_HEAD(&head->hch_bucket,
rmx_q);
}
uma_zfree_smr(V_tcp_hostcache.zone, hc_entry);
head->hch_length--;
atomic_subtract_int(&V_tcp_hostcache.cache_count, 1);
} else {
atomic_subtract_int(&hc_entry->rmx_expire,
V_tcp_hostcache.prune);
hc_prev = hc_entry;
}
}
THC_UNLOCK(head);
}
}
/*
* 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) {
if (V_tcp_hostcache.purgeall == 2)
V_tcp_hostcache.hashsalt = arc4random();
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();
}
/*
* Expire and purge all entries in hostcache immediately.
*/
static int
sysctl_tcp_hc_purgenow(SYSCTL_HANDLER_ARGS)
{
int error, val;
val = 0;
error = sysctl_handle_int(oidp, &val, 0, req);
if (error || !req->newptr)
return (error);
if (val == 2)
V_tcp_hostcache.hashsalt = arc4random();
tcp_hc_purge_internal(1);
callout_reset(&V_tcp_hc_callout, V_tcp_hostcache.prune * hz,
tcp_hc_purge, curvnet);
return (0);
}
