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NetBSD/usr.bin/netstat/netstat.h
dyoung c2e43be1c5 Reduces the resources demanded by TCP sessions in TIME_WAIT-state using 
methods called Vestigial Time-Wait (VTW) and Maximum Segment Lifetime
Truncation (MSLT).

MSLT and VTW were contributed by Coyote Point Systems, Inc.

Even after a TCP session enters the TIME_WAIT state, its corresponding
socket and protocol control blocks (PCBs) stick around until the TCP
Maximum Segment Lifetime (MSL) expires.  On a host whose workload
necessarily creates and closes down many TCP sockets, the sockets & PCBs
for TCP sessions in TIME_WAIT state amount to many megabytes of dead
weight in RAM.

Maximum Segment Lifetimes Truncation (MSLT) assigns each TCP session to
a class based on the nearness of the peer.  Corresponding to each class
is an MSL, and a session uses the MSL of its class.  The classes are
loopback (local host equals remote host), local (local host and remote
host are on the same link/subnet), and remote (local host and remote
host communicate via one or more gateways).  Classes corresponding to
nearer peers have lower MSLs by default: 2 seconds for loopback, 10
seconds for local, 60 seconds for remote.  Loopback and local sessions
expire more quickly when MSLT is used.

Vestigial Time-Wait (VTW) replaces a TIME_WAIT session's PCB/socket
dead weight with a compact representation of the session, called a
"vestigial PCB".  VTW data structures are designed to be very fast and
memory-efficient: for fast insertion and lookup of vestigial PCBs,
the PCBs are stored in a hash table that is designed to minimize the
number of cacheline visits per lookup/insertion.  The memory both
for vestigial PCBs and for elements of the PCB hashtable come from
fixed-size pools, and linked data structures exploit this to conserve
memory by representing references with a narrow index/offset from the
start of a pool instead of a pointer.  When space for new vestigial PCBs
runs out, VTW makes room by discarding old vestigial PCBs, oldest first.
VTW cooperates with MSLT.

It may help to think of VTW as a "FIN cache" by analogy to the SYN
cache.

A 2.8-GHz Pentium 4 running a test workload that creates TIME_WAIT
sessions as fast as it can is approximately 17% idle when VTW is active
versus 0% idle when VTW is inactive.  It has 103 megabytes more free RAM
when VTW is active (approximately 64k vestigial PCBs are created) than
when it is inactive.
2011-05-03 18:28:44 +00:00

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/* $NetBSD: netstat.h,v 1.42 2011/05/03 18:28:46 dyoung Exp $ */
/*
* Copyright (c) 1992, 1993
* Regents of the University of California. 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. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS 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 REGENTS 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.
*
* from: @(#)netstat.h 8.2 (Berkeley) 1/4/94
*/
#include <sys/cdefs.h>
#include <kvm.h>
int Aflag; /* show addresses of protocol control block */
int aflag; /* show all sockets (including servers) */
int Bflag; /* show Berkeley Packet Filter information */
int bflag; /* show i/f byte stats */
int dflag; /* show i/f dropped packets */
#ifndef SMALL
int gflag; /* show group (multicast) routing or stats */
#endif
int hflag; /* humanize byte counts */
int iflag; /* show interfaces */
int Lflag; /* don't show LLINFO entries */
int lflag; /* show routing table with use and ref */
int mflag; /* show memory stats */
int numeric_addr; /* show addresses numerically */
int numeric_port; /* show ports numerically */
int nflag; /* same as above, for show.c compat */
int Pflag; /* dump a PCB */
int pflag; /* show given protocol */
int qflag; /* show softintrq */
int rflag; /* show routing tables (or routing stats) */
int sflag; /* show protocol statistics */
int tagflag; /* show route tags */
int tflag; /* show i/f watchdog timers */
int Vflag; /* show Vestigial TIME_WAIT (VTW) information */
int vflag; /* verbose route information or don't truncate names */
char *interface; /* desired i/f for stats, or NULL for all i/fs */
int af; /* address family */
int use_sysctl; /* use sysctl instead of kmem */
int force_sysctl; /* force use of sysctl (or exit) - for testing */
int kread __P((u_long addr, char *buf, int size));
const char *plural __P((int));
const char *plurales __P((int));
int get_hardticks __P((void));
void protopr __P((u_long, const char *));
void tcp_stats __P((u_long, const char *));
void tcp_dump __P((u_long));
void udp_stats __P((u_long, const char *));
void ip_stats __P((u_long, const char *));
void icmp_stats __P((u_long, const char *));
void igmp_stats __P((u_long, const char *));
void pim_stats __P((u_long, const char *));
void arp_stats __P((u_long, const char *));
void carp_stats __P((u_long, const char *));
void pfsync_stats __P((u_long, const char*));
#ifdef IPSEC
/* run-time selector for which implementation (KAME, FAST_IPSEC) to show */
void ipsec_switch __P((u_long, const char *));
/* KAME ipsec version */
void ipsec_stats __P((u_long, const char *));
/* FAST_IPSEC version */
void fast_ipsec_stats __P((u_long, const char *));
#endif
#ifdef INET6
struct sockaddr_in6;
struct in6_addr;
void ip6protopr __P((u_long, const char *));
void tcp6_stats __P((u_long, const char *));
void tcp6_dump __P((u_long));
void udp6_stats __P((u_long, const char *));
void ip6_stats __P((u_long, const char *));
void ip6_ifstats __P((const char *));
void icmp6_stats __P((u_long, const char *));
void icmp6_ifstats __P((const char *));
void pim6_stats __P((u_long, const char *));
void rip6_stats __P((u_long, const char *));
void mroute6pr __P((u_long, u_long, u_long));
void mrt6_stats __P((u_long, u_long));
char *routename6 __P((struct sockaddr_in6 *));
#endif /*INET6*/
#ifdef IPSEC
void pfkey_stats __P((u_long, const char *));
#endif
void mbpr(u_long, u_long, u_long, u_long, u_long);
void hostpr __P((u_long, u_long));
void impstats __P((u_long, u_long));
void pr_rthdr __P((int, int));
void pr_family __P((int));
void rt_stats __P((u_long));
char *ns_phost __P((struct sockaddr *));
void upHex __P((char *));
void p_rttables(int);
void p_flags(int, const char *);
void p_addr(struct sockaddr *, struct sockaddr *, int);
void p_gwaddr(struct sockaddr *, int);
void p_sockaddr(struct sockaddr *, struct sockaddr *, int, int);
char *routename(struct sockaddr *);
char *routename4(in_addr_t);
char *netname(struct sockaddr *, struct sockaddr *);
char *netname4(in_addr_t, in_addr_t);
/* char *routename __P((u_int32_t)); */
/* char *netname __P((u_int32_t, u_int32_t)); */
#ifdef INET6
char *netname6 __P((struct sockaddr_in6 *, struct sockaddr_in6 *));
#endif
const char *atalk_print __P((const struct sockaddr *, int));
const char *atalk_print2 __P((const struct sockaddr *, const struct sockaddr *,
int));
char *ns_print __P((struct sockaddr *));
void routepr __P((u_long));
void nsprotopr __P((u_long, const char *));
void spp_stats __P((u_long, const char *));
void idp_stats __P((u_long, const char *));
void nserr_stats __P((u_long, const char *));
void atalkprotopr __P((u_long, const char *));
void ddp_stats __P((u_long, const char *));
void intpr __P((int, u_long, void (*) __P((const char *))));
void unixpr __P((u_long));
void esis_stats __P((u_long, const char *));
void clnp_stats __P((u_long, const char *));
void cltp_stats __P((u_long, const char *));
void iso_protopr __P((u_long, const char *));
void iso_protopr1 __P((u_long, int));
void tp_protopr __P((u_long, const char *));
void tp_inproto __P((u_long));
void tp_stats __P((u_long, const char *));
void mroutepr __P((u_long, u_long, u_long, u_long));
void mrt_stats __P((u_long, u_long));
void bpf_stats(void);
void bpf_dump(const char *);
kvm_t *get_kvmd(void);
#define PLEN (LONG_BIT / 4 + 2)
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