src/slirp/tcp_timer.h

/*
 * Copyright (c) 1982, 1986, 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.
 *
 *      @(#)tcp_timer.h 8.1 (Berkeley) 6/10/93
 * tcp_timer.h,v 1.4 1994/08/21 05:27:38 paul Exp
 */

#ifndef _TCP_TIMER_H_
#define _TCP_TIMER_H_

/*
 * Definitions of the TCP timers.  These timers are counted
 * down PR_SLOWHZ times a second.
 */
#define TCPT_NTIMERS    4

#define TCPT_REXMT      0               /* retransmit */
#define TCPT_PERSIST    1               /* retransmit persistence */
#define TCPT_KEEP       2               /* keep alive */
#define TCPT_2MSL       3               /* 2*msl quiet time timer */

/*
 * The TCPT_REXMT timer is used to force retransmissions.
 * The TCP has the TCPT_REXMT timer set whenever segments
 * have been sent for which ACKs are expected but not yet
 * received.  If an ACK is received which advances tp->snd_una,
 * then the retransmit timer is cleared (if there are no more
 * outstanding segments) or reset to the base value (if there
 * are more ACKs expected).  Whenever the retransmit timer goes off,
 * we retransmit one unacknowledged segment, and do a backoff
 * on the retransmit timer.
 *
 * The TCPT_PERSIST timer is used to keep window size information
 * flowing even if the window goes shut.  If all previous transmissions
 * have been acknowledged (so that there are no retransmissions in progress),
 * and the window is too small to bother sending anything, then we start
 * the TCPT_PERSIST timer.  When it expires, if the window is nonzero,
 * we go to transmit state.  Otherwise, at intervals send a single byte
 * into the peer's window to force him to update our window information.
 * We do this at most as often as TCPT_PERSMIN time intervals,
 * but no more frequently than the current estimate of round-trip
 * packet time.  The TCPT_PERSIST timer is cleared whenever we receive
 * a window update from the peer.
 *
 * The TCPT_KEEP timer is used to keep connections alive.  If an
 * connection is idle (no segments received) for TCPTV_KEEP_INIT amount of time,
 * but not yet established, then we drop the connection.  Once the connection
 * is established, if the connection is idle for TCPTV_KEEP_IDLE time
 * (and keepalives have been enabled on the socket), we begin to probe
 * the connection.  We force the peer to send us a segment by sending:
 *      <SEQ=SND.UNA-1><ACK=RCV.NXT><CTL=ACK>
 * This segment is (deliberately) outside the window, and should elicit
 * an ack segment in response from the peer.  If, despite the TCPT_KEEP
 * initiated segments we cannot elicit a response from a peer in TCPT_MAXIDLE
 * amount of time probing, then we drop the connection.
 */

/*
 * Time constants.
 */
#define TCPTV_MSL       ( 5*PR_SLOWHZ)          /* max seg lifetime (hah!) */

#define TCPTV_SRTTBASE  0                       /* base roundtrip time;
                                                   if 0, no idea yet */
#define TCPTV_SRTTDFLT  (  3*PR_SLOWHZ)         /* assumed RTT if no info */

#define TCPTV_PERSMIN   (  5*PR_SLOWHZ)         /* retransmit persistence */
#define TCPTV_PERSMAX   ( 60*PR_SLOWHZ)         /* maximum persist interval */

#define TCPTV_KEEP_INIT ( 75*PR_SLOWHZ)         /* initial connect keep alive */
#define TCPTV_KEEP_IDLE (120*60*PR_SLOWHZ)      /* dflt time before probing */
#define TCPTV_KEEPINTVL ( 75*PR_SLOWHZ)         /* default probe interval */
#define TCPTV_KEEPCNT   8                       /* max probes before drop */

#define TCPTV_MIN       (  1*PR_SLOWHZ)         /* minimum allowable value */
/* #define      TCPTV_REXMTMAX  ( 64*PR_SLOWHZ) */      /* max allowable REXMT value */
#define TCPTV_REXMTMAX  ( 12*PR_SLOWHZ)         /* max allowable REXMT value */

#define TCP_LINGERTIME  120                     /* linger at most 2 minutes */

#define TCP_MAXRXTSHIFT 12                      /* maximum retransmits */


#ifdef  TCPTIMERS
char *tcptimers[] =
    { "REXMT", "PERSIST", "KEEP", "2MSL" };
#endif

/*
 * Force a time value to be in a certain range.
 */
#define TCPT_RANGESET(tv, value, tvmin, tvmax) { \
        (tv) = (value); \
        if ((tv) < (tvmin)) \
                (tv) = (tvmin); \
        else if ((tv) > (tvmax)) \
                (tv) = (tvmax); \
}

extern int tcp_keepidle;                /* time before keepalive probes begin */
extern int tcp_keepintvl;               /* time between keepalive probes */
extern int tcp_maxidle;                 /* time to drop after starting probes */
extern int tcp_ttl;                     /* time to live for TCP segs */
extern int tcp_backoff[];

struct tcpcb;

void tcp_fasttimo _P((void));
void tcp_slowtimo _P((void));
void tcp_canceltimers _P((struct tcpcb *));
struct tcpcb * tcp_timers _P((register struct tcpcb *, int));

#endif
Revision:	1.2
Committed:	2012-03-30T01:10:28Z (12 years, 7 months ago) by asvitkine
Content type:	text/plain
Branch:	MAIN
CVS Tags:	HEAD
Changes since 1.1:	+1 -5 lines
Log Message:	Switch slirp to 3-clause BSD license. This change went in upstream to QEMU's version of slirp (where this code comes from), with the following checkin: commit 2f5f89963186d42a7ded253bc6cf5b32abb45cec Author: aliguori <aliguori@c046a42c-6fe2-441c-8c8c-71466251a162> Date: Mon Jan 26 19:37:41 2009 +0000 Remove the advertising clause from the slirp license According to the FSF, the 4-clause BSD license, which slirp is covered under, is not compatible with the GPL or LGPL[1]. [1] http://www.fsf.org/licensing/licenses/index_html#GPLIncompatibleLicenses There are three declared copyright holders in slirp that use the 4-clause BSD license, the Regents of UC Berkley, Danny Gasparovski, and Kelly Price. Below are the appropriate permissions to remove the advertise clause from slirp from each party. Special thanks go to Richard Fontana from Red Hat for contacting all of the necessary authors to resolve this issue! Regents of UC Berkley: From ftp://ftp.cs.berkeley.edu/pub/4bsd/README.Impt.License.Change July 22, 1999 To All Licensees, Distributors of Any Version of BSD: As you know, certain of the Berkeley Software Distribution ("BSD") source code files require that further distributions of products containing all or portions of the software, acknowledge within their advertising materials that such products contain software developed by UC Berkeley and its contributors. Specifically, the provision reads: " * 3. All advertising materials mentioning features or use of this software * must display the following acknowledgement: * This product includes software developed by the University of * California, Berkeley and its contributors." Effective immediately, licensees and distributors are no longer required to include the acknowledgement within advertising materials. Accordingly, the foregoing paragraph of those BSD Unix files containing it is hereby deleted in its entirety. William Hoskins Director, Office of Technology Licensing University of California, Berkeley Danny Gasparovski: Subject: RE: Slirp license Date: Thu, 8 Jan 2009 10:51:00 +1100 From: "Gasparovski, Daniel" <Daniel.Gasparovski@ato.gov.au> To: "Richard Fontana" <rfontana@redhat.com> Hi Richard, I have no objection to having Slirp code in QEMU be licensed under the 3-clause BSD license. Thanks for taking the effort to consult me about this. Dan ... Kelly Price: Date: Thu, 8 Jan 2009 19:38:56 -0500 From: "Kelly Price" <strredwolf@gmail.com> To: "Richard Fontana" <rfontana@redhat.com> Subject: Re: Slirp license Thanks for contacting me, Richard. I'm glad you were able to find Dan, as I've been "keeping the light on" for Slirp. I have no use for it now, and I have little time for it (now holding onto Keenspot's Comic Genesis and having a regular US state government position). If Dan would like to return to the project, I'd love to give it back to him. As for copyright, I don't own all of it. Dan does, so I will defer to him. Any of my patches I will gladly license to the 3-part BSD license. My interest in re-licensing was because we didn't have ready info to contact Dan. If Dan would like to port Slirp back out of QEMU, a lot of us 64-bit users would be grateful. Feel free to share this email address with Dan. I will be glad to effect a transfer of the project to him and Mr. Bellard of the QEMU project. Signed-off-by: Anthony Liguori <aliguori@us.ibm.com> git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@6451 c046a42c-6fe2-441c-8c8c-71466251a162
#	User	Rev	Content
1	gbeauche	1.1	/*
2			* Copyright (c) 1982, 1986, 1993
3			* The Regents of the University of California. All rights reserved.
4			*
5			* Redistribution and use in source and binary forms, with or without
6			* modification, are permitted provided that the following conditions
7			* are met:
8			* 1. Redistributions of source code must retain the above copyright
9			* notice, this list of conditions and the following disclaimer.
10			* 2. Redistributions in binary form must reproduce the above copyright
11			* notice, this list of conditions and the following disclaimer in the
12			* documentation and/or other materials provided with the distribution.
13	asvitkine	1.2	* 3. Neither the name of the University nor the names of its contributors
14	gbeauche	1.1	* may be used to endorse or promote products derived from this software
15			* without specific prior written permission.
16			*
17			* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
18			* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19			* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20			* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
21			* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22			* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23			* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24			* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25			* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26			* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27			* SUCH DAMAGE.
28			*
29			* @(#)tcp_timer.h 8.1 (Berkeley) 6/10/93
30			* tcp_timer.h,v 1.4 1994/08/21 05:27:38 paul Exp
31			*/
32
33			#ifndef _TCP_TIMER_H_
34			#define _TCP_TIMER_H_
35
36			/*
37			* Definitions of the TCP timers. These timers are counted
38			* down PR_SLOWHZ times a second.
39			*/
40			#define TCPT_NTIMERS 4
41
42			#define TCPT_REXMT 0 /* retransmit */
43			#define TCPT_PERSIST 1 /* retransmit persistence */
44			#define TCPT_KEEP 2 /* keep alive */
45			#define TCPT_2MSL 3 /* 2msl quiet time timer /
46
47			/*
48			* The TCPT_REXMT timer is used to force retransmissions.
49			* The TCP has the TCPT_REXMT timer set whenever segments
50			* have been sent for which ACKs are expected but not yet
51			* received. If an ACK is received which advances tp->snd_una,
52			* then the retransmit timer is cleared (if there are no more
53			* outstanding segments) or reset to the base value (if there
54			* are more ACKs expected). Whenever the retransmit timer goes off,
55			* we retransmit one unacknowledged segment, and do a backoff
56			* on the retransmit timer.
57			*
58			* The TCPT_PERSIST timer is used to keep window size information
59			* flowing even if the window goes shut. If all previous transmissions
60			* have been acknowledged (so that there are no retransmissions in progress),
61			* and the window is too small to bother sending anything, then we start
62			* the TCPT_PERSIST timer. When it expires, if the window is nonzero,
63			* we go to transmit state. Otherwise, at intervals send a single byte
64			* into the peer's window to force him to update our window information.
65			* We do this at most as often as TCPT_PERSMIN time intervals,
66			* but no more frequently than the current estimate of round-trip
67			* packet time. The TCPT_PERSIST timer is cleared whenever we receive
68			* a window update from the peer.
69			*
70			* The TCPT_KEEP timer is used to keep connections alive. If an
71			* connection is idle (no segments received) for TCPTV_KEEP_INIT amount of time,
72			* but not yet established, then we drop the connection. Once the connection
73			* is established, if the connection is idle for TCPTV_KEEP_IDLE time
74			* (and keepalives have been enabled on the socket), we begin to probe
75			* the connection. We force the peer to send us a segment by sending:
76			* <SEQ=SND.UNA-1><ACK=RCV.NXT><CTL=ACK>
77			* This segment is (deliberately) outside the window, and should elicit
78			* an ack segment in response from the peer. If, despite the TCPT_KEEP
79			* initiated segments we cannot elicit a response from a peer in TCPT_MAXIDLE
80			* amount of time probing, then we drop the connection.
81			*/
82
83			/*
84			* Time constants.
85			*/
86			#define TCPTV_MSL ( 5PR_SLOWHZ) / max seg lifetime (hah!) */
87
88			#define TCPTV_SRTTBASE 0 /* base roundtrip time;
89			if 0, no idea yet */
90			#define TCPTV_SRTTDFLT ( 3PR_SLOWHZ) / assumed RTT if no info */
91
92			#define TCPTV_PERSMIN ( 5PR_SLOWHZ) / retransmit persistence */
93			#define TCPTV_PERSMAX ( 60PR_SLOWHZ) / maximum persist interval */
94
95			#define TCPTV_KEEP_INIT ( 75PR_SLOWHZ) / initial connect keep alive */
96			#define TCPTV_KEEP_IDLE (12060PR_SLOWHZ) /* dflt time before probing */
97			#define TCPTV_KEEPINTVL ( 75PR_SLOWHZ) / default probe interval */
98			#define TCPTV_KEEPCNT 8 /* max probes before drop */
99
100			#define TCPTV_MIN ( 1PR_SLOWHZ) / minimum allowable value */
101			/* #define TCPTV_REXMTMAX ( 64PR_SLOWHZ) / /* max allowable REXMT value */
102			#define TCPTV_REXMTMAX ( 12PR_SLOWHZ) / max allowable REXMT value */
103
104			#define TCP_LINGERTIME 120 /* linger at most 2 minutes */
105
106			#define TCP_MAXRXTSHIFT 12 /* maximum retransmits */
107
108
109			#ifdef TCPTIMERS
110			char *tcptimers[] =
111			{ "REXMT", "PERSIST", "KEEP", "2MSL" };
112			#endif
113
114			/*
115			* Force a time value to be in a certain range.
116			*/
117			#define TCPT_RANGESET(tv, value, tvmin, tvmax) { \
118			(tv) = (value); \
119			if ((tv) < (tvmin)) \
120			(tv) = (tvmin); \
121			else if ((tv) > (tvmax)) \
122			(tv) = (tvmax); \
123			}
124
125			extern int tcp_keepidle; /* time before keepalive probes begin */
126			extern int tcp_keepintvl; /* time between keepalive probes */
127			extern int tcp_maxidle; /* time to drop after starting probes */
128			extern int tcp_ttl; /* time to live for TCP segs */
129			extern int tcp_backoff[];
130
131			struct tcpcb;
132
133			void tcp_fasttimo _P((void));
134			void tcp_slowtimo _P((void));
135			void tcp_canceltimers _P((struct tcpcb *));
136			struct tcpcb * tcp_timers _P((register struct tcpcb *, int));
137
138			#endif