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[unix-history] / sys / netinet / tcp_var.h
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1/*
2 * Copyright (c) 1982, 1986 Regents of the University of California.
3 * 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 * 3. All advertising materials mentioning features or use of this software
14 * must display the following acknowledgement:
15 * This product includes software developed by the University of
16 * California, Berkeley and its contributors.
17 * 4. Neither the name of the University nor the names of its contributors
18 * may be used to endorse or promote products derived from this software
19 * without specific prior written permission.
20 *
21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31 * SUCH DAMAGE.
32 *
38e82238 33 * from: @(#)tcp_var.h 7.10 (Berkeley) 6/28/90
fde1aeb2 34 * $Id: tcp_var.h,v 1.4 1993/11/25 01:35:21 wollman Exp $
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35 */
36
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37#ifndef _NETINET_TCP_VAR_H_
38#define _NETINET_TCP_VAR_H_ 1
39
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40/*
41 * Kernel variables for tcp.
42 */
43
44/*
45 * Tcp control block, one per tcp; fields:
46 */
47struct tcpcb {
48 struct tcpiphdr *seg_next; /* sequencing queue */
49 struct tcpiphdr *seg_prev;
50 short t_state; /* state of this connection */
51 short t_timer[TCPT_NTIMERS]; /* tcp timers */
52 short t_rxtshift; /* log(2) of rexmt exp. backoff */
53 short t_rxtcur; /* current retransmit value */
54 short t_dupacks; /* consecutive dup acks recd */
55 u_short t_maxseg; /* maximum segment size */
56 char t_force; /* 1 if forcing out a byte */
57 u_char t_flags;
58#define TF_ACKNOW 0x01 /* ack peer immediately */
59#define TF_DELACK 0x02 /* ack, but try to delay it */
60#define TF_NODELAY 0x04 /* don't delay packets to coalesce */
61#define TF_NOOPT 0x08 /* don't use tcp options */
62#define TF_SENTFIN 0x10 /* have sent FIN */
63 struct tcpiphdr *t_template; /* skeletal packet for transmit */
64 struct inpcb *t_inpcb; /* back pointer to internet pcb */
65/*
66 * The following fields are used as in the protocol specification.
67 * See RFC783, Dec. 1981, page 21.
68 */
69/* send sequence variables */
70 tcp_seq snd_una; /* send unacknowledged */
71 tcp_seq snd_nxt; /* send next */
72 tcp_seq snd_up; /* send urgent pointer */
73 tcp_seq snd_wl1; /* window update seg seq number */
74 tcp_seq snd_wl2; /* window update seg ack number */
75 tcp_seq iss; /* initial send sequence number */
76 u_short snd_wnd; /* send window */
77/* receive sequence variables */
78 u_short rcv_wnd; /* receive window */
79 tcp_seq rcv_nxt; /* receive next */
80 tcp_seq rcv_up; /* receive urgent pointer */
81 tcp_seq irs; /* initial receive sequence number */
82/*
83 * Additional variables for this implementation.
84 */
85/* receive variables */
86 tcp_seq rcv_adv; /* advertised window */
87/* retransmit variables */
88 tcp_seq snd_max; /* highest sequence number sent;
89 * used to recognize retransmits
90 */
91/* congestion control (for slow start, source quench, retransmit after loss) */
92 u_short snd_cwnd; /* congestion-controlled window */
93 u_short snd_ssthresh; /* snd_cwnd size threshhold for
94 * for slow start exponential to
95 * linear switch
96 */
97/*
98 * transmit timing stuff. See below for scale of srtt and rttvar.
99 * "Variance" is actually smoothed difference.
100 */
101 short t_idle; /* inactivity time */
102 short t_rtt; /* round trip time */
103 tcp_seq t_rtseq; /* sequence number being timed */
104 short t_srtt; /* smoothed round-trip time */
105 short t_rttvar; /* variance in round-trip time */
106 u_short t_rttmin; /* minimum rtt allowed */
107 u_short max_sndwnd; /* largest window peer has offered */
108
109/* out-of-band data */
110 char t_oobflags; /* have some */
111 char t_iobc; /* input character */
112#define TCPOOB_HAVEDATA 0x01
113#define TCPOOB_HADDATA 0x02
114 short t_softerror; /* possible error not yet reported */
115};
116
117#define intotcpcb(ip) ((struct tcpcb *)(ip)->inp_ppcb)
118#define sototcpcb(so) (intotcpcb(sotoinpcb(so)))
119
120/*
121 * The smoothed round-trip time and estimated variance
122 * are stored as fixed point numbers scaled by the values below.
123 * For convenience, these scales are also used in smoothing the average
124 * (smoothed = (1/scale)sample + ((scale-1)/scale)smoothed).
125 * With these scales, srtt has 3 bits to the right of the binary point,
126 * and thus an "ALPHA" of 0.875. rttvar has 2 bits to the right of the
127 * binary point, and is smoothed with an ALPHA of 0.75.
128 */
129#define TCP_RTT_SCALE 8 /* multiplier for srtt; 3 bits frac. */
130#define TCP_RTT_SHIFT 3 /* shift for srtt; 3 bits frac. */
131#define TCP_RTTVAR_SCALE 4 /* multiplier for rttvar; 2 bits */
132#define TCP_RTTVAR_SHIFT 2 /* multiplier for rttvar; 2 bits */
133
134/*
135 * The initial retransmission should happen at rtt + 4 * rttvar.
136 * Because of the way we do the smoothing, srtt and rttvar
137 * will each average +1/2 tick of bias. When we compute
138 * the retransmit timer, we want 1/2 tick of rounding and
139 * 1 extra tick because of +-1/2 tick uncertainty in the
140 * firing of the timer. The bias will give us exactly the
141 * 1.5 tick we need. But, because the bias is
142 * statistical, we have to test that we don't drop below
143 * the minimum feasible timer (which is 2 ticks).
144 * This macro assumes that the value of TCP_RTTVAR_SCALE
145 * is the same as the multiplier for rttvar.
146 */
147#define TCP_REXMTVAL(tp) \
148 (((tp)->t_srtt >> TCP_RTT_SHIFT) + (tp)->t_rttvar)
149
150/* XXX
151 * We want to avoid doing m_pullup on incoming packets but that
152 * means avoiding dtom on the tcp reassembly code. That in turn means
153 * keeping an mbuf pointer in the reassembly queue (since we might
154 * have a cluster). As a quick hack, the source & destination
155 * port numbers (which are no longer needed once we've located the
156 * tcpcb) are overlayed with an mbuf pointer.
157 */
158#define REASS_MBUF(ti) (*(struct mbuf **)&((ti)->ti_t))
159
160/*
161 * TCP statistics.
162 * Many of these should be kept per connection,
163 * but that's inconvenient at the moment.
164 */
165struct tcpstat {
166 u_long tcps_connattempt; /* connections initiated */
167 u_long tcps_accepts; /* connections accepted */
168 u_long tcps_connects; /* connections established */
169 u_long tcps_drops; /* connections dropped */
170 u_long tcps_conndrops; /* embryonic connections dropped */
171 u_long tcps_closed; /* conn. closed (includes drops) */
172 u_long tcps_segstimed; /* segs where we tried to get rtt */
173 u_long tcps_rttupdated; /* times we succeeded */
174 u_long tcps_delack; /* delayed acks sent */
175 u_long tcps_timeoutdrop; /* conn. dropped in rxmt timeout */
176 u_long tcps_rexmttimeo; /* retransmit timeouts */
177 u_long tcps_persisttimeo; /* persist timeouts */
178 u_long tcps_keeptimeo; /* keepalive timeouts */
179 u_long tcps_keepprobe; /* keepalive probes sent */
180 u_long tcps_keepdrops; /* connections dropped in keepalive */
181
182 u_long tcps_sndtotal; /* total packets sent */
183 u_long tcps_sndpack; /* data packets sent */
184 u_long tcps_sndbyte; /* data bytes sent */
185 u_long tcps_sndrexmitpack; /* data packets retransmitted */
186 u_long tcps_sndrexmitbyte; /* data bytes retransmitted */
187 u_long tcps_sndacks; /* ack-only packets sent */
188 u_long tcps_sndprobe; /* window probes sent */
189 u_long tcps_sndurg; /* packets sent with URG only */
190 u_long tcps_sndwinup; /* window update-only packets sent */
191 u_long tcps_sndctrl; /* control (SYN|FIN|RST) packets sent */
192
193 u_long tcps_rcvtotal; /* total packets received */
194 u_long tcps_rcvpack; /* packets received in sequence */
195 u_long tcps_rcvbyte; /* bytes received in sequence */
196 u_long tcps_rcvbadsum; /* packets received with ccksum errs */
197 u_long tcps_rcvbadoff; /* packets received with bad offset */
198 u_long tcps_rcvshort; /* packets received too short */
199 u_long tcps_rcvduppack; /* duplicate-only packets received */
200 u_long tcps_rcvdupbyte; /* duplicate-only bytes received */
201 u_long tcps_rcvpartduppack; /* packets with some duplicate data */
202 u_long tcps_rcvpartdupbyte; /* dup. bytes in part-dup. packets */
203 u_long tcps_rcvoopack; /* out-of-order packets received */
204 u_long tcps_rcvoobyte; /* out-of-order bytes received */
205 u_long tcps_rcvpackafterwin; /* packets with data after window */
206 u_long tcps_rcvbyteafterwin; /* bytes rcvd after window */
207 u_long tcps_rcvafterclose; /* packets rcvd after "close" */
208 u_long tcps_rcvwinprobe; /* rcvd window probe packets */
209 u_long tcps_rcvdupack; /* rcvd duplicate acks */
210 u_long tcps_rcvacktoomuch; /* rcvd acks for unsent data */
211 u_long tcps_rcvackpack; /* rcvd ack packets */
212 u_long tcps_rcvackbyte; /* bytes acked by rcvd acks */
213 u_long tcps_rcvwinupd; /* rcvd window update packets */
214};
215
216#ifdef KERNEL
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217extern struct inpcb tcb; /* head of queue of active tcpcb's */
218extern struct tcpstat tcpstat; /* tcp statistics */
4c45483e 219
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220/* From tcp_input.c: */
221extern int tcp_reass(struct tcpcb *, struct tcpiphdr *, struct mbuf *);
222extern void tcp_input(struct mbuf *, int);
223extern int tcp_mss(struct tcpcb *, int /*u_short*/);
4c45483e 224
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225/* From tcp_output.c: */
226extern int tcp_output(struct tcpcb *);
227extern void tcp_setpersist(struct tcpcb *);
4c45483e 228
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229/* From tcp_subr.c: */
230extern void tcp_init(void);
231extern struct tcpiphdr *tcp_template(struct tcpcb *);
232extern void tcp_respond(struct tcpcb *, struct tcpiphdr *, struct mbuf *,
233 tcp_seq, tcp_seq, int);
234extern struct tcpcb *tcp_newtcpcb(struct inpcb *);
235extern struct tcpcb *tcp_drop(struct tcpcb *, int);
236extern struct tcpcb *tcp_close(struct tcpcb *);
237extern void tcp_drain(void);
238extern void tcp_notify(struct inpcb *, int);
239#ifdef MTUDISC
240extern void tcp_checkmtu(struct inpcb *, int);
241extern void tcp_mtuchanged(struct inpcb *, int);
15637ed4 242#endif
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243extern void tcp_ctlinput(int, struct sockaddr *, struct ip *);
244extern void tcp_quench(struct inpcb *, int);
245
246/* From tcp_timer.c: */
247extern void tcp_fasttimo(void);
248extern void tcp_slowtimo(void);
249extern void tcp_canceltimers(struct tcpcb *);
250extern struct tcpcb *tcp_timers(struct tcpcb *, int);
251
252/* From tcp_usrreq.c: */
253extern int tcp_usrreq(struct socket *, int, struct mbuf *, struct mbuf *,
254 struct mbuf *, struct mbuf *);
255extern int tcp_ctloutput(int, struct socket *, int, int, struct mbuf **);
256extern int tcp_attach(struct socket *);
257extern struct tcpcb *tcp_disconnect(struct tcpcb *);
258extern struct tcpcb *tcp_usrclosed(struct tcpcb *);
259
260extern struct inpcb *tcp_last_inpcb;
261
262/* From in_var.c: */
263extern int tcp_ttl;
264extern int tcp_mssdflt;
265extern int tcp_rttdflt;
266extern int tcp_keepidle;
267extern int tcp_keepintvl;
268extern int tcp_maxidle;
269extern u_long tcp_sendspace;
270extern u_long tcp_recvspace;
271
272#endif /* KERNEL */
8ace4366 273#endif /* _NETINET_TCP_VAR_H_ */