2
* Copyright (c) 1982, 1986, 1993, 1994
3
* The Regents of the University of California. All rights reserved.
5
* Redistribution and use in source and binary forms, with or without
6
* modification, are permitted provided that the following conditions
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. Neither the name of the University nor the names of its contributors
14
* may be used to endorse or promote products derived from this software
15
* without specific prior written permission.
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
29
* @(#)tcp_var.h 8.3 (Berkeley) 4/10/94
30
* tcp_var.h,v 1.3 1994/08/21 05:27:39 paul Exp
37
#include "tcp_timer.h"
40
* Tcp control block, one per tcp; fields:
43
struct tcpiphdr *seg_next; /* sequencing queue */
44
struct tcpiphdr *seg_prev;
45
short t_state; /* state of this connection */
46
short t_timer[TCPT_NTIMERS]; /* tcp timers */
47
short t_rxtshift; /* log(2) of rexmt exp. backoff */
48
short t_rxtcur; /* current retransmit value */
49
short t_dupacks; /* consecutive dup acks recd */
50
u_short t_maxseg; /* maximum segment size */
51
char t_force; /* 1 if forcing out a byte */
53
#define TF_ACKNOW 0x0001 /* ack peer immediately */
54
#define TF_DELACK 0x0002 /* ack, but try to delay it */
55
#define TF_NODELAY 0x0004 /* don't delay packets to coalesce */
56
#define TF_NOOPT 0x0008 /* don't use tcp options */
57
#define TF_SENTFIN 0x0010 /* have sent FIN */
58
#define TF_REQ_SCALE 0x0020 /* have/will request window scaling */
59
#define TF_RCVD_SCALE 0x0040 /* other side has requested scaling */
60
#define TF_REQ_TSTMP 0x0080 /* have/will request timestamps */
61
#define TF_RCVD_TSTMP 0x0100 /* a timestamp was received in SYN */
62
#define TF_SACK_PERMIT 0x0200 /* other side said I could SACK */
64
/* Make it static for now */
65
/* struct tcpiphdr *t_template; / * skeletal packet for transmit */
66
struct tcpiphdr t_template;
68
struct socket *t_socket; /* back pointer to socket */
70
* The following fields are used as in the protocol specification.
71
* See RFC783, Dec. 1981, page 21.
73
/* send sequence variables */
74
tcp_seq snd_una; /* send unacknowledged */
75
tcp_seq snd_nxt; /* send next */
76
tcp_seq snd_up; /* send urgent pointer */
77
tcp_seq snd_wl1; /* window update seg seq number */
78
tcp_seq snd_wl2; /* window update seg ack number */
79
tcp_seq iss; /* initial send sequence number */
80
u_int32_t snd_wnd; /* send window */
81
/* receive sequence variables */
82
u_int32_t rcv_wnd; /* receive window */
83
tcp_seq rcv_nxt; /* receive next */
84
tcp_seq rcv_up; /* receive urgent pointer */
85
tcp_seq irs; /* initial receive sequence number */
87
* Additional variables for this implementation.
89
/* receive variables */
90
tcp_seq rcv_adv; /* advertised window */
91
/* retransmit variables */
92
tcp_seq snd_max; /* highest sequence number sent;
93
* used to recognize retransmits
95
/* congestion control (for slow start, source quench, retransmit after loss) */
96
u_int32_t snd_cwnd; /* congestion-controlled window */
97
u_int32_t snd_ssthresh; /* snd_cwnd size threshold for
98
* for slow start exponential to
102
* transmit timing stuff. See below for scale of srtt and rttvar.
103
* "Variance" is actually smoothed difference.
105
short t_idle; /* inactivity time */
106
short t_rtt; /* round trip time */
107
tcp_seq t_rtseq; /* sequence number being timed */
108
short t_srtt; /* smoothed round-trip time */
109
short t_rttvar; /* variance in round-trip time */
110
u_short t_rttmin; /* minimum rtt allowed */
111
u_int32_t max_sndwnd; /* largest window peer has offered */
113
/* out-of-band data */
114
char t_oobflags; /* have some */
115
char t_iobc; /* input character */
116
#define TCPOOB_HAVEDATA 0x01
117
#define TCPOOB_HADDATA 0x02
118
short t_softerror; /* possible error not yet reported */
120
/* RFC 1323 variables */
121
u_char snd_scale; /* window scaling for send window */
122
u_char rcv_scale; /* window scaling for recv window */
123
u_char request_r_scale; /* pending window scaling */
124
u_char requested_s_scale;
125
u_int32_t ts_recent; /* timestamp echo data */
126
u_int32_t ts_recent_age; /* when last updated */
127
tcp_seq last_ack_sent;
131
#define sototcpcb(so) ((so)->so_tcpcb)
134
* The smoothed round-trip time and estimated variance
135
* are stored as fixed point numbers scaled by the values below.
136
* For convenience, these scales are also used in smoothing the average
137
* (smoothed = (1/scale)sample + ((scale-1)/scale)smoothed).
138
* With these scales, srtt has 3 bits to the right of the binary point,
139
* and thus an "ALPHA" of 0.875. rttvar has 2 bits to the right of the
140
* binary point, and is smoothed with an ALPHA of 0.75.
142
#define TCP_RTT_SCALE 8 /* multiplier for srtt; 3 bits frac. */
143
#define TCP_RTT_SHIFT 3 /* shift for srtt; 3 bits frac. */
144
#define TCP_RTTVAR_SCALE 4 /* multiplier for rttvar; 2 bits */
145
#define TCP_RTTVAR_SHIFT 2 /* multiplier for rttvar; 2 bits */
148
* The initial retransmission should happen at rtt + 4 * rttvar.
149
* Because of the way we do the smoothing, srtt and rttvar
150
* will each average +1/2 tick of bias. When we compute
151
* the retransmit timer, we want 1/2 tick of rounding and
152
* 1 extra tick because of +-1/2 tick uncertainty in the
153
* firing of the timer. The bias will give us exactly the
154
* 1.5 tick we need. But, because the bias is
155
* statistical, we have to test that we don't drop below
156
* the minimum feasible timer (which is 2 ticks).
157
* This macro assumes that the value of TCP_RTTVAR_SCALE
158
* is the same as the multiplier for rttvar.
160
#define TCP_REXMTVAL(tp) \
161
(((tp)->t_srtt >> TCP_RTT_SHIFT) + (tp)->t_rttvar)
166
* Many of these should be kept per connection,
167
* but that's inconvenient at the moment.
170
u_long tcps_connattempt; /* connections initiated */
171
u_long tcps_accepts; /* connections accepted */
172
u_long tcps_connects; /* connections established */
173
u_long tcps_drops; /* connections dropped */
174
u_long tcps_conndrops; /* embryonic connections dropped */
175
u_long tcps_closed; /* conn. closed (includes drops) */
176
u_long tcps_segstimed; /* segs where we tried to get rtt */
177
u_long tcps_rttupdated; /* times we succeeded */
178
u_long tcps_delack; /* delayed acks sent */
179
u_long tcps_timeoutdrop; /* conn. dropped in rxmt timeout */
180
u_long tcps_rexmttimeo; /* retransmit timeouts */
181
u_long tcps_persisttimeo; /* persist timeouts */
182
u_long tcps_keeptimeo; /* keepalive timeouts */
183
u_long tcps_keepprobe; /* keepalive probes sent */
184
u_long tcps_keepdrops; /* connections dropped in keepalive */
186
u_long tcps_sndtotal; /* total packets sent */
187
u_long tcps_sndpack; /* data packets sent */
188
u_long tcps_sndbyte; /* data bytes sent */
189
u_long tcps_sndrexmitpack; /* data packets retransmitted */
190
u_long tcps_sndrexmitbyte; /* data bytes retransmitted */
191
u_long tcps_sndacks; /* ack-only packets sent */
192
u_long tcps_sndprobe; /* window probes sent */
193
u_long tcps_sndurg; /* packets sent with URG only */
194
u_long tcps_sndwinup; /* window update-only packets sent */
195
u_long tcps_sndctrl; /* control (SYN|FIN|RST) packets sent */
197
u_long tcps_rcvtotal; /* total packets received */
198
u_long tcps_rcvpack; /* packets received in sequence */
199
u_long tcps_rcvbyte; /* bytes received in sequence */
200
u_long tcps_rcvbadsum; /* packets received with ccksum errs */
201
u_long tcps_rcvbadoff; /* packets received with bad offset */
202
/* u_long tcps_rcvshort; */ /* packets received too short */
203
u_long tcps_rcvduppack; /* duplicate-only packets received */
204
u_long tcps_rcvdupbyte; /* duplicate-only bytes received */
205
u_long tcps_rcvpartduppack; /* packets with some duplicate data */
206
u_long tcps_rcvpartdupbyte; /* dup. bytes in part-dup. packets */
207
u_long tcps_rcvoopack; /* out-of-order packets received */
208
u_long tcps_rcvoobyte; /* out-of-order bytes received */
209
u_long tcps_rcvpackafterwin; /* packets with data after window */
210
u_long tcps_rcvbyteafterwin; /* bytes rcvd after window */
211
u_long tcps_rcvafterclose; /* packets rcvd after "close" */
212
u_long tcps_rcvwinprobe; /* rcvd window probe packets */
213
u_long tcps_rcvdupack; /* rcvd duplicate acks */
214
u_long tcps_rcvacktoomuch; /* rcvd acks for unsent data */
215
u_long tcps_rcvackpack; /* rcvd ack packets */
216
u_long tcps_rcvackbyte; /* bytes acked by rcvd acks */
217
u_long tcps_rcvwinupd; /* rcvd window update packets */
218
/* u_long tcps_pawsdrop; */ /* segments dropped due to PAWS */
219
u_long tcps_predack; /* times hdr predict ok for acks */
220
u_long tcps_preddat; /* times hdr predict ok for data pkts */
221
u_long tcps_socachemiss; /* tcp_last_so misses */
222
u_long tcps_didnuttin; /* Times tcp_output didn't do anything XXX */
225
extern struct tcpstat tcpstat; /* tcp statistics */
228
extern u_int32_t tcp_now; /* for RFC 1323 timestamps */