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NetBSD/sys/netinet6/in6_pcb.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: in6_pcb.h,v 1.35 2011/05/03 18:28:45 dyoung Exp $ */
/* $KAME: in6_pcb.h,v 1.45 2001/02/09 05:59:46 itojun Exp $ */
/*
* Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
* 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 project 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 PROJECT 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 PROJECT 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.
*/
/*
* Copyright (c) 1982, 1986, 1990, 1993
* The 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.
*
* @(#)in_pcb.h 8.1 (Berkeley) 6/10/93
*/
#ifndef _NETINET6_IN6_PCB_H_
#define _NETINET6_IN6_PCB_H_
#include <sys/queue.h>
#include <netinet/in_pcb_hdr.h>
/*
* Common structure pcb for internet protocol implementation.
* Here are stored pointers to local and foreign host table
* entries, local and foreign socket numbers, and pointers
* up (to a socket structure) and down (to a protocol-specific)
* control block.
*/
struct icmp6_filter;
struct in6pcb {
struct inpcb_hdr in6p_head;
#define in6p_hash in6p_head.inph_hash
#define in6p_queue in6p_head.inph_queue
#define in6p_af in6p_head.inph_af
#define in6p_ppcb in6p_head.inph_ppcb
#define in6p_state in6p_head.inph_state
#define in6p_socket in6p_head.inph_socket
#define in6p_table in6p_head.inph_table
#define in6p_sp in6p_head.inph_sp
struct route in6p_route; /* placeholder for routing entry */
u_int16_t in6p_fport; /* foreign port */
u_int16_t in6p_lport; /* local port */
u_int32_t in6p_flowinfo; /* priority and flowlabel */
int in6p_flags; /* generic IP6/datagram flags */
int in6p_hops; /* default hop limit */
struct ip6_hdr in6p_ip6; /* header prototype */
struct mbuf *in6p_options; /* IP6 options */
struct ip6_pktopts *in6p_outputopts; /* IP6 options for outgoing packets */
struct ip6_moptions *in6p_moptions; /* IP6 multicast options */
struct icmp6_filter *in6p_icmp6filt;
int in6p_cksum; /* IPV6_CHECKSUM setsockopt */
};
#define in6p_faddr in6p_ip6.ip6_dst
#define in6p_laddr in6p_ip6.ip6_src
/* states in inp_state: */
#define IN6P_ATTACHED INP_ATTACHED
#define IN6P_BOUND INP_BOUND
#define IN6P_CONNECTED INP_CONNECTED
/*
* Flags in in6p_flags
* We define KAME's original flags in higher 16 bits as much as possible
* for compatibility with *bsd*s.
*/
#define IN6P_RECVOPTS 0x001000 /* receive incoming IP6 options */
#define IN6P_RECVRETOPTS 0x002000 /* receive IP6 options for reply */
#define IN6P_RECVDSTADDR 0x004000 /* receive IP6 dst address */
#define IN6P_IPV6_V6ONLY 0x008000 /* restrict AF_INET6 socket for v6 */
#define IN6P_PKTINFO 0x010000 /* receive IP6 dst and I/F */
#define IN6P_HOPLIMIT 0x020000 /* receive hoplimit */
#define IN6P_HOPOPTS 0x040000 /* receive hop-by-hop options */
#define IN6P_DSTOPTS 0x080000 /* receive dst options after rthdr */
#define IN6P_RTHDR 0x100000 /* receive routing header */
#define IN6P_RTHDRDSTOPTS 0x200000 /* receive dstoptions before rthdr */
#define IN6P_TCLASS 0x400000 /* traffic class */
#define IN6P_HIGHPORT 0x1000000 /* user wants "high" port binding */
#define IN6P_LOWPORT 0x2000000 /* user wants "low" port binding */
#define IN6P_ANONPORT 0x4000000 /* port chosen for user */
#define IN6P_FAITH 0x8000000 /* accept FAITH'ed connections */
#define IN6P_RFC2292 0x40000000 /* RFC2292 */
#define IN6P_MTU 0x80000000 /* use minimum MTU */
#define IN6P_CONTROLOPTS (IN6P_PKTINFO|IN6P_HOPLIMIT|IN6P_HOPOPTS|\
IN6P_DSTOPTS|IN6P_RTHDR|IN6P_RTHDRDSTOPTS|\
IN6P_TCLASS|IN6P_RFC2292|\
IN6P_MTU)
#ifdef _KERNEL
/* compute hash value for foreign and local in6_addr and port */
#define IN6_HASH(faddr, fport, laddr, lport) \
(((faddr)->s6_addr32[0] ^ (faddr)->s6_addr32[1] ^ \
(faddr)->s6_addr32[2] ^ (faddr)->s6_addr32[3] ^ \
(laddr)->s6_addr32[0] ^ (laddr)->s6_addr32[1] ^ \
(laddr)->s6_addr32[2] ^ (laddr)->s6_addr32[3]) \
+ (fport) + (lport))
#define sotoin6pcb(so) ((struct in6pcb *)(so)->so_pcb)
void in6_losing(struct in6pcb *);
void in6_pcbinit(struct inpcbtable *, int, int);
int in6_pcballoc(struct socket *, void *);
int in6_pcbbind(void *, struct mbuf *, struct lwp *);
int in6_pcbconnect(void *, struct mbuf *, struct lwp *);
void in6_pcbdetach(struct in6pcb *);
void in6_pcbdisconnect(struct in6pcb *);
struct in6pcb *in6_pcblookup_port(struct inpcbtable *, struct in6_addr *,
u_int, int, struct vestigial_inpcb *);
int in6_pcbnotify(struct inpcbtable *, const struct sockaddr *,
u_int, const struct sockaddr *, u_int, int, void *,
void (*)(struct in6pcb *, int));
void in6_pcbpurgeif0(struct inpcbtable *, struct ifnet *);
void in6_pcbpurgeif(struct inpcbtable *, struct ifnet *);
void in6_pcbstate(struct in6pcb *, int);
void in6_rtchange(struct in6pcb *, int);
void in6_setpeeraddr(struct in6pcb *, struct mbuf *);
void in6_setsockaddr(struct in6pcb *, struct mbuf *);
/* in in6_src.c */
int in6_selecthlim(struct in6pcb *, struct ifnet *);
int in6_pcbsetport(struct sockaddr_in6 *, struct in6pcb *, struct lwp *);
extern struct rtentry *
in6_pcbrtentry(struct in6pcb *);
extern struct in6pcb *in6_pcblookup_connect(struct inpcbtable *,
const struct in6_addr *, u_int, const struct in6_addr *, u_int, int,
struct vestigial_inpcb *);
extern struct in6pcb *in6_pcblookup_bind(struct inpcbtable *,
const struct in6_addr *, u_int, int);
#endif /* _KERNEL */
#endif /* !_NETINET6_IN6_PCB_H_ */
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