freebsd-dev/sys/netinet/tcp_stats.c
Edward Tomasz Napierala adc56f5a38 Make use of the stats(3) framework in the TCP stack.
This makes it possible to retrieve per-connection statistical
information such as the receive window size, RTT, or goodput,
using a newly added TCP_STATS getsockopt(3) option, and extract
them using the stats_voistat_fetch(3) API.

See the net/tcprtt port for an example consumer of this API.

Compared to the existing TCP_INFO system, the main differences
are that this mechanism is easy to extend without breaking ABI,
and provides statistical information instead of raw "snapshots"
of values at a given point in time.  stats(3) is more generic
and can be used in both userland and the kernel.

Reviewed by:	thj
Tested by:	thj
Obtained from:	Netflix
Relnotes:	yes
Sponsored by:	Klara Inc, Netflix
Differential Revision:	https://reviews.freebsd.org/D20655
2019-12-02 20:58:04 +00:00

275 lines
8.4 KiB
C

/*-
* Copyright (c) 2016-2018 Netflix, Inc.
* 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.
*
* 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.
*/
/*
* Author: Lawrence Stewart <lstewart@netflix.com>
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <sys/param.h>
#include <sys/arb.h>
#include <sys/errno.h>
#include <sys/malloc.h>
#include <sys/qmath.h>
#include <sys/queue.h>
#include <sys/socket.h>
#include <sys/socketvar.h>
#include <sys/sysctl.h>
#ifdef _KERNEL
#include <sys/kernel.h>
#include <sys/lock.h>
#include <sys/rmlock.h>
#include <sys/systm.h>
#endif
#include <sys/stats.h>
#include <net/vnet.h>
#include <netinet/in.h>
#include <netinet/in_pcb.h>
#include <netinet/tcp.h>
#include <netinet/tcp_var.h>
#include <netinet/cc/cc.h>
VNET_DEFINE(int, tcp_perconn_stats_dflt_tpl) = -1;
#ifndef _KERNEL
#define V_tcp_perconn_stats_enable VNET(tcp_perconn_stats_enable)
#define V_tcp_perconn_stats_dflt_tpl VNET(tcp_perconn_stats_dflt_tpl)
#else /* _KERNEL */
VNET_DEFINE(int, tcp_perconn_stats_enable) = 2;
VNET_DEFINE_STATIC(struct stats_tpl_sample_rate *, tcp_perconn_stats_sample_rates);
VNET_DEFINE_STATIC(int, tcp_stats_nrates) = 0;
#define V_tcp_perconn_stats_sample_rates VNET(tcp_perconn_stats_sample_rates)
#define V_tcp_stats_nrates VNET(tcp_stats_nrates)
static struct rmlock tcp_stats_tpl_sampling_lock;
static int tcp_stats_tpl_sr_cb(enum stats_tpl_sr_cb_action action,
struct stats_tpl_sample_rate **rates, int *nrates, void *ctx);
SYSCTL_INT(_net_inet_tcp, OID_AUTO, perconn_stats_enable,
CTLFLAG_VNET | CTLFLAG_RW, &VNET_NAME(tcp_perconn_stats_enable), 0,
"Enable per-connection TCP stats gathering; 1 enables for all connections, "
"2 enables random sampling across log id connection groups");
SYSCTL_PROC(_net_inet_tcp, OID_AUTO, perconn_stats_sample_rates,
CTLTYPE_STRING | CTLFLAG_RW, tcp_stats_tpl_sr_cb,
sizeof(struct rm_priotracker), stats_tpl_sample_rates, "A",
"TCP stats per template random sampling rates, in CSV tpl_spec=percent "
"key-value pairs (see stats(9) for template spec details)");
#endif /* _KERNEL */
#ifdef _KERNEL
int
#else
static int
/* Ensure all templates are also added to the userland template list. */
__attribute__ ((constructor))
#endif
tcp_stats_init()
{
int err, lasterr;
err = lasterr = 0;
V_tcp_perconn_stats_dflt_tpl = stats_tpl_alloc("TCP_DEFAULT", 0);
if (V_tcp_perconn_stats_dflt_tpl < 0)
return (-V_tcp_perconn_stats_dflt_tpl);
struct voistatspec vss_sum[] = {
STATS_VSS_SUM(),
};
err |= stats_tpl_add_voistats(V_tcp_perconn_stats_dflt_tpl,
VOI_TCP_TXPB, "TCP_TXPB", VSD_DTYPE_INT_U64,
NVSS(vss_sum), vss_sum, 0);
lasterr = err ? err : lasterr;
err |= stats_tpl_add_voistats(V_tcp_perconn_stats_dflt_tpl,
VOI_TCP_RETXPB, "TCP_RETXPB", VSD_DTYPE_INT_U32,
NVSS(vss_sum), vss_sum, 0);
lasterr = err ? err : lasterr;
struct voistatspec vss_max[] = {
STATS_VSS_MAX(),
};
err |= stats_tpl_add_voistats(V_tcp_perconn_stats_dflt_tpl,
VOI_TCP_FRWIN, "TCP_FRWIN", VSD_DTYPE_INT_ULONG,
NVSS(vss_max), vss_max, 0);
lasterr = err ? err : lasterr;
err |= stats_tpl_add_voistats(V_tcp_perconn_stats_dflt_tpl,
VOI_TCP_LCWIN, "TCP_LCWIN", VSD_DTYPE_INT_ULONG,
NVSS(vss_max), vss_max, 0);
lasterr = err ? err : lasterr;
struct voistatspec vss_rtt[] = {
STATS_VSS_MAX(),
STATS_VSS_MIN(),
STATS_VSS_TDGSTCLUST32(20, 4),
};
err |= stats_tpl_add_voistats(V_tcp_perconn_stats_dflt_tpl,
VOI_TCP_RTT, "TCP_RTT", VSD_DTYPE_INT_U32,
NVSS(vss_rtt), vss_rtt, 0);
lasterr = err ? err : lasterr;
struct voistatspec vss_congsig[] = {
STATS_VSS_DVHIST32_USR(HBKTS(DVBKT(CC_ECN), DVBKT(CC_RTO),
DVBKT(CC_RTO_ERR), DVBKT(CC_NDUPACK)), 0)
};
err |= stats_tpl_add_voistats(V_tcp_perconn_stats_dflt_tpl,
VOI_TCP_CSIG, "TCP_CSIG", VSD_DTYPE_INT_U32,
NVSS(vss_congsig), vss_congsig, 0);
lasterr = err ? err : lasterr;
struct voistatspec vss_gput[] = {
STATS_VSS_MAX(),
STATS_VSS_TDGSTCLUST32(20, 4),
};
err |= stats_tpl_add_voistats(V_tcp_perconn_stats_dflt_tpl,
VOI_TCP_GPUT, "TCP_GPUT", VSD_DTYPE_INT_U32,
NVSS(vss_gput), vss_gput, 0);
lasterr = err ? err : lasterr;
struct voistatspec vss_gput_nd[] = {
STATS_VSS_TDGSTCLUST32(10, 4),
};
err |= stats_tpl_add_voistats(V_tcp_perconn_stats_dflt_tpl,
VOI_TCP_GPUT_ND, "TCP_GPUT_ND", VSD_DTYPE_INT_S32,
NVSS(vss_gput_nd), vss_gput_nd, 0);
lasterr = err ? err : lasterr;
struct voistatspec vss_windiff[] = {
STATS_VSS_CRHIST32_USR(HBKTS(CRBKT(0)), VSD_HIST_LBOUND_INF)
};
err |= stats_tpl_add_voistats(V_tcp_perconn_stats_dflt_tpl,
VOI_TCP_CALCFRWINDIFF, "TCP_CALCFRWINDIFF", VSD_DTYPE_INT_S32,
NVSS(vss_windiff), vss_windiff, 0);
lasterr = err ? err : lasterr;
struct voistatspec vss_acklen[] = {
STATS_VSS_MAX(),
STATS_VSS_CRHIST32_LIN(0, 9, 1, VSD_HIST_UBOUND_INF)
};
err |= stats_tpl_add_voistats(V_tcp_perconn_stats_dflt_tpl,
VOI_TCP_ACKLEN, "TCP_ACKLEN", VSD_DTYPE_INT_U32,
NVSS(vss_acklen), vss_acklen, 0);
lasterr = err ? err : lasterr;
return (lasterr);
}
#ifdef _KERNEL
int
tcp_stats_sample_rollthedice(struct tcpcb *tp, void *seed_bytes,
size_t seed_len)
{
struct rm_priotracker tracker;
int tpl;
tpl = -1;
if (V_tcp_stats_nrates > 0) {
rm_rlock(&tcp_stats_tpl_sampling_lock, &tracker);
tpl = stats_tpl_sample_rollthedice(V_tcp_perconn_stats_sample_rates,
V_tcp_stats_nrates, seed_bytes, seed_len);
rm_runlock(&tcp_stats_tpl_sampling_lock, &tracker);
if (tpl >= 0) {
INP_WLOCK_ASSERT(tp->t_inpcb);
if (tp->t_stats != NULL)
stats_blob_destroy(tp->t_stats);
tp->t_stats = stats_blob_alloc(tpl, 0);
if (tp->t_stats == NULL)
tpl = -ENOMEM;
}
}
return (tpl);
}
/*
* Callback function for stats_tpl_sample_rates() to interact with the TCP
* subsystem's stats template sample rates list.
*/
int
tcp_stats_tpl_sr_cb(enum stats_tpl_sr_cb_action action,
struct stats_tpl_sample_rate **rates, int *nrates, void *ctx)
{
struct stats_tpl_sample_rate *old_rates;
int old_nrates;
if (ctx == NULL)
return (ENOMEM);
switch (action) {
case TPL_SR_RLOCKED_GET:
/*
* Return with rlock held i.e. this call must be paired with a
* "action == TPL_SR_RUNLOCK" call.
*/
rm_assert(&tcp_stats_tpl_sampling_lock, RA_UNLOCKED);
rm_rlock(&tcp_stats_tpl_sampling_lock,
(struct rm_priotracker *)ctx);
/* FALLTHROUGH */
case TPL_SR_UNLOCKED_GET:
if (rates != NULL)
*rates = V_tcp_perconn_stats_sample_rates;
if (nrates != NULL)
*nrates = V_tcp_stats_nrates;
break;
case TPL_SR_RUNLOCK:
rm_assert(&tcp_stats_tpl_sampling_lock, RA_RLOCKED);
rm_runlock(&tcp_stats_tpl_sampling_lock,
(struct rm_priotracker *)ctx);
break;
case TPL_SR_PUT:
KASSERT(rates != NULL && nrates != NULL,
("%s: PUT without new rates", __func__));
rm_assert(&tcp_stats_tpl_sampling_lock, RA_UNLOCKED);
if (rates == NULL || nrates == NULL)
return (EINVAL);
rm_wlock(&tcp_stats_tpl_sampling_lock);
old_rates = V_tcp_perconn_stats_sample_rates;
old_nrates = V_tcp_stats_nrates;
V_tcp_perconn_stats_sample_rates = *rates;
V_tcp_stats_nrates = *nrates;
rm_wunlock(&tcp_stats_tpl_sampling_lock);
*rates = old_rates;
*nrates = old_nrates;
break;
default:
return (EINVAL);
break;
}
return (0);
}
RM_SYSINIT(tcp_stats_tpl_sampling_lock, &tcp_stats_tpl_sampling_lock,
"tcp_stats_tpl_sampling_lock");
#endif /* _KERNEL */