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1.1 root 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: *
33: * @(#)tcp_var.h 7.10 (Berkeley) 6/28/90
34: */
35:
36: /*
37: * Kernel variables for tcp.
38: */
39:
40: /*
41: * Tcp control block, one per tcp; fields:
42: */
43: struct tcpcb {
44: struct tcpiphdr *seg_next; /* sequencing queue */
45: struct tcpiphdr *seg_prev;
46: short t_state; /* state of this connection */
47: short t_timer[TCPT_NTIMERS]; /* tcp timers */
48: short t_rxtshift; /* log(2) of rexmt exp. backoff */
49: short t_rxtcur; /* current retransmit value */
50: short t_dupacks; /* consecutive dup acks recd */
51: u_short t_maxseg; /* maximum segment size */
52: char t_force; /* 1 if forcing out a byte */
53: u_char t_flags;
54: #define TF_ACKNOW 0x01 /* ack peer immediately */
55: #define TF_DELACK 0x02 /* ack, but try to delay it */
56: #define TF_NODELAY 0x04 /* don't delay packets to coalesce */
57: #define TF_NOOPT 0x08 /* don't use tcp options */
58: #define TF_SENTFIN 0x10 /* have sent FIN */
59: struct tcpiphdr *t_template; /* skeletal packet for transmit */
60: struct inpcb *t_inpcb; /* back pointer to internet pcb */
61: /*
62: * The following fields are used as in the protocol specification.
63: * See RFC783, Dec. 1981, page 21.
64: */
65: /* send sequence variables */
66: tcp_seq snd_una; /* send unacknowledged */
67: tcp_seq snd_nxt; /* send next */
68: tcp_seq snd_up; /* send urgent pointer */
69: tcp_seq snd_wl1; /* window update seg seq number */
70: tcp_seq snd_wl2; /* window update seg ack number */
71: tcp_seq iss; /* initial send sequence number */
72: u_short snd_wnd; /* send window */
73: /* receive sequence variables */
74: u_short rcv_wnd; /* receive window */
75: tcp_seq rcv_nxt; /* receive next */
76: tcp_seq rcv_up; /* receive urgent pointer */
77: tcp_seq irs; /* initial receive sequence number */
78: /*
79: * Additional variables for this implementation.
80: */
81: /* receive variables */
82: tcp_seq rcv_adv; /* advertised window */
83: /* retransmit variables */
84: tcp_seq snd_max; /* highest sequence number sent;
85: * used to recognize retransmits
86: */
87: /* congestion control (for slow start, source quench, retransmit after loss) */
88: u_short snd_cwnd; /* congestion-controlled window */
89: u_short snd_ssthresh; /* snd_cwnd size threshhold for
90: * for slow start exponential to
91: * linear switch
92: */
93: /*
94: * transmit timing stuff. See below for scale of srtt and rttvar.
95: * "Variance" is actually smoothed difference.
96: */
97: short t_idle; /* inactivity time */
98: short t_rtt; /* round trip time */
99: tcp_seq t_rtseq; /* sequence number being timed */
100: short t_srtt; /* smoothed round-trip time */
101: short t_rttvar; /* variance in round-trip time */
102: u_short t_rttmin; /* minimum rtt allowed */
103: u_short max_sndwnd; /* largest window peer has offered */
104:
105: /* out-of-band data */
106: char t_oobflags; /* have some */
107: char t_iobc; /* input character */
108: #define TCPOOB_HAVEDATA 0x01
109: #define TCPOOB_HADDATA 0x02
110: short t_softerror; /* possible error not yet reported */
111: };
112:
113: #define intotcpcb(ip) ((struct tcpcb *)(ip)->inp_ppcb)
114: #define sototcpcb(so) (intotcpcb(sotoinpcb(so)))
115:
116: /*
117: * The smoothed round-trip time and estimated variance
118: * are stored as fixed point numbers scaled by the values below.
119: * For convenience, these scales are also used in smoothing the average
120: * (smoothed = (1/scale)sample + ((scale-1)/scale)smoothed).
121: * With these scales, srtt has 3 bits to the right of the binary point,
122: * and thus an "ALPHA" of 0.875. rttvar has 2 bits to the right of the
123: * binary point, and is smoothed with an ALPHA of 0.75.
124: */
125: #define TCP_RTT_SCALE 8 /* multiplier for srtt; 3 bits frac. */
126: #define TCP_RTT_SHIFT 3 /* shift for srtt; 3 bits frac. */
127: #define TCP_RTTVAR_SCALE 4 /* multiplier for rttvar; 2 bits */
128: #define TCP_RTTVAR_SHIFT 2 /* multiplier for rttvar; 2 bits */
129:
130: /*
131: * The initial retransmission should happen at rtt + 4 * rttvar.
132: * Because of the way we do the smoothing, srtt and rttvar
133: * will each average +1/2 tick of bias. When we compute
134: * the retransmit timer, we want 1/2 tick of rounding and
135: * 1 extra tick because of +-1/2 tick uncertainty in the
136: * firing of the timer. The bias will give us exactly the
137: * 1.5 tick we need. But, because the bias is
138: * statistical, we have to test that we don't drop below
139: * the minimum feasible timer (which is 2 ticks).
140: * This macro assumes that the value of TCP_RTTVAR_SCALE
141: * is the same as the multiplier for rttvar.
142: */
143: #define TCP_REXMTVAL(tp) \
144: (((tp)->t_srtt >> TCP_RTT_SHIFT) + (tp)->t_rttvar)
145:
146: /* XXX
147: * We want to avoid doing m_pullup on incoming packets but that
148: * means avoiding dtom on the tcp reassembly code. That in turn means
149: * keeping an mbuf pointer in the reassembly queue (since we might
150: * have a cluster). As a quick hack, the source & destination
151: * port numbers (which are no longer needed once we've located the
152: * tcpcb) are overlayed with an mbuf pointer.
153: */
154: #define REASS_MBUF(ti) (*(struct mbuf **)&((ti)->ti_t))
155:
156: /*
157: * TCP statistics.
158: * Many of these should be kept per connection,
159: * but that's inconvenient at the moment.
160: */
161: struct tcpstat {
162: u_long tcps_connattempt; /* connections initiated */
163: u_long tcps_accepts; /* connections accepted */
164: u_long tcps_connects; /* connections established */
165: u_long tcps_drops; /* connections dropped */
166: u_long tcps_conndrops; /* embryonic connections dropped */
167: u_long tcps_closed; /* conn. closed (includes drops) */
168: u_long tcps_segstimed; /* segs where we tried to get rtt */
169: u_long tcps_rttupdated; /* times we succeeded */
170: u_long tcps_delack; /* delayed acks sent */
171: u_long tcps_timeoutdrop; /* conn. dropped in rxmt timeout */
172: u_long tcps_rexmttimeo; /* retransmit timeouts */
173: u_long tcps_persisttimeo; /* persist timeouts */
174: u_long tcps_keeptimeo; /* keepalive timeouts */
175: u_long tcps_keepprobe; /* keepalive probes sent */
176: u_long tcps_keepdrops; /* connections dropped in keepalive */
177:
178: u_long tcps_sndtotal; /* total packets sent */
179: u_long tcps_sndpack; /* data packets sent */
180: u_long tcps_sndbyte; /* data bytes sent */
181: u_long tcps_sndrexmitpack; /* data packets retransmitted */
182: u_long tcps_sndrexmitbyte; /* data bytes retransmitted */
183: u_long tcps_sndacks; /* ack-only packets sent */
184: u_long tcps_sndprobe; /* window probes sent */
185: u_long tcps_sndurg; /* packets sent with URG only */
186: u_long tcps_sndwinup; /* window update-only packets sent */
187: u_long tcps_sndctrl; /* control (SYN|FIN|RST) packets sent */
188:
189: u_long tcps_rcvtotal; /* total packets received */
190: u_long tcps_rcvpack; /* packets received in sequence */
191: u_long tcps_rcvbyte; /* bytes received in sequence */
192: u_long tcps_rcvbadsum; /* packets received with ccksum errs */
193: u_long tcps_rcvbadoff; /* packets received with bad offset */
194: u_long tcps_rcvshort; /* packets received too short */
195: u_long tcps_rcvduppack; /* duplicate-only packets received */
196: u_long tcps_rcvdupbyte; /* duplicate-only bytes received */
197: u_long tcps_rcvpartduppack; /* packets with some duplicate data */
198: u_long tcps_rcvpartdupbyte; /* dup. bytes in part-dup. packets */
199: u_long tcps_rcvoopack; /* out-of-order packets received */
200: u_long tcps_rcvoobyte; /* out-of-order bytes received */
201: u_long tcps_rcvpackafterwin; /* packets with data after window */
202: u_long tcps_rcvbyteafterwin; /* bytes rcvd after window */
203: u_long tcps_rcvafterclose; /* packets rcvd after "close" */
204: u_long tcps_rcvwinprobe; /* rcvd window probe packets */
205: u_long tcps_rcvdupack; /* rcvd duplicate acks */
206: u_long tcps_rcvacktoomuch; /* rcvd acks for unsent data */
207: u_long tcps_rcvackpack; /* rcvd ack packets */
208: u_long tcps_rcvackbyte; /* bytes acked by rcvd acks */
209: u_long tcps_rcvwinupd; /* rcvd window update packets */
210: };
211:
212: #ifdef KERNEL
213: struct inpcb tcb; /* head of queue of active tcpcb's */
214: struct tcpstat tcpstat; /* tcp statistics */
215: struct tcpiphdr *tcp_template();
216: struct tcpcb *tcp_close(), *tcp_drop();
217: struct tcpcb *tcp_timers(), *tcp_disconnect(), *tcp_usrclosed();
218: #endif
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