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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 is only permitted until one year after the first shipment
6: * of 4.4BSD by the Regents. Otherwise, redistribution and use in source and
7: * binary forms are permitted provided that: (1) source distributions retain
8: * this entire copyright notice and comment, and (2) distributions including
9: * binaries display the following acknowledgement: This product includes
10: * software developed by the University of California, Berkeley and its
11: * contributors'' in the documentation or other materials provided with the
12: * distribution and in all advertising materials mentioning features or use
13: * of this software. Neither the name of the University nor the names of
14: * its contributors may be used to endorse or promote products derived from
15: * this software without specific prior written permission.
16: * THIS SOFTWARE IS PROVIDED AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED
17: * WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
18: * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
19: *
20: * @(#)tcp_var.h 7.10 (Berkeley) 6/28/90
21: */
22:
23: /*
24: * Kernel variables for tcp.
25: */
26:
27: /*
28: * Tcp control block, one per tcp; fields:
29: */
30: struct tcpcb {
31: struct tcpiphdr *seg_next; /* sequencing queue */
32: struct tcpiphdr *seg_prev;
33: short t_state; /* state of this connection */
34: short t_timer[TCPT_NTIMERS]; /* tcp timers */
35: short t_rxtshift; /* log(2) of rexmt exp. backoff */
36: short t_rxtcur; /* current retransmit value */
37: short t_dupacks; /* consecutive dup acks recd */
38: u_short t_maxseg; /* maximum segment size */
39: char t_force; /* 1 if forcing out a byte */
40: u_char t_flags;
41: #define TF_ACKNOW 0x01 /* ack peer immediately */
42: #define TF_DELACK 0x02 /* ack, but try to delay it */
43: #define TF_NODELAY 0x04 /* don't delay packets to coalesce */
44: #define TF_NOOPT 0x08 /* don't use tcp options */
45: #define TF_SENTFIN 0x10 /* have sent FIN */
46: struct tcpiphdr *t_template; /* skeletal packet for transmit */
47: struct inpcb *t_inpcb; /* back pointer to internet pcb */
48: /*
49: * The following fields are used as in the protocol specification.
50: * See RFC783, Dec. 1981, page 21.
51: */
52: /* send sequence variables */
53: tcp_seq snd_una; /* send unacknowledged */
54: tcp_seq snd_nxt; /* send next */
55: tcp_seq snd_up; /* send urgent pointer */
56: tcp_seq snd_wl1; /* window update seg seq number */
57: tcp_seq snd_wl2; /* window update seg ack number */
58: tcp_seq iss; /* initial send sequence number */
59: u_short snd_wnd; /* send window */
60: /* receive sequence variables */
61: u_short rcv_wnd; /* receive window */
62: tcp_seq rcv_nxt; /* receive next */
63: tcp_seq rcv_up; /* receive urgent pointer */
64: tcp_seq irs; /* initial receive sequence number */
65: /*
66: * Additional variables for this implementation.
67: */
68: /* receive variables */
69: tcp_seq rcv_adv; /* advertised window */
70: /* retransmit variables */
71: tcp_seq snd_max; /* highest sequence number sent;
72: * used to recognize retransmits
73: */
74: /* congestion control (for slow start, source quench, retransmit after loss) */
75: u_short snd_cwnd; /* congestion-controlled window */
76: u_short snd_ssthresh; /* snd_cwnd size threshhold for
77: * for slow start exponential to
78: * linear switch
79: */
80: /*
81: * transmit timing stuff. See below for scale of srtt and rttvar.
82: * "Variance" is actually smoothed difference.
83: */
84: short t_idle; /* inactivity time */
85: short t_rtt; /* round trip time */
86: tcp_seq t_rtseq; /* sequence number being timed */
87: short t_srtt; /* smoothed round-trip time */
88: short t_rttvar; /* variance in round-trip time */
89: u_short t_rttmin; /* minimum rtt allowed */
90: u_short max_sndwnd; /* largest window peer has offered */
91:
92: /* out-of-band data */
93: char t_oobflags; /* have some */
94: char t_iobc; /* input character */
95: #define TCPOOB_HAVEDATA 0x01
96: #define TCPOOB_HADDATA 0x02
97: short t_softerror; /* possible error not yet reported */
98: };
99:
100: #define intotcpcb(ip) ((struct tcpcb *)(ip)->inp_ppcb)
101: #define sototcpcb(so) (intotcpcb(sotoinpcb(so)))
102:
103: /*
104: * The smoothed round-trip time and estimated variance
105: * are stored as fixed point numbers scaled by the values below.
106: * For convenience, these scales are also used in smoothing the average
107: * (smoothed = (1/scale)sample + ((scale-1)/scale)smoothed).
108: * With these scales, srtt has 3 bits to the right of the binary point,
109: * and thus an "ALPHA" of 0.875. rttvar has 2 bits to the right of the
110: * binary point, and is smoothed with an ALPHA of 0.75.
111: */
112: #define TCP_RTT_SCALE 8 /* multiplier for srtt; 3 bits frac. */
113: #define TCP_RTT_SHIFT 3 /* shift for srtt; 3 bits frac. */
114: #define TCP_RTTVAR_SCALE 4 /* multiplier for rttvar; 2 bits */
115: #define TCP_RTTVAR_SHIFT 2 /* multiplier for rttvar; 2 bits */
116:
117: /*
118: * The initial retransmission should happen at rtt + 4 * rttvar.
119: * Because of the way we do the smoothing, srtt and rttvar
120: * will each average +1/2 tick of bias. When we compute
121: * the retransmit timer, we want 1/2 tick of rounding and
122: * 1 extra tick because of +-1/2 tick uncertainty in the
123: * firing of the timer. The bias will give us exactly the
124: * 1.5 tick we need. But, because the bias is
125: * statistical, we have to test that we don't drop below
126: * the minimum feasible timer (which is 2 ticks).
127: * This macro assumes that the value of TCP_RTTVAR_SCALE
128: * is the same as the multiplier for rttvar.
129: */
130: #define TCP_REXMTVAL(tp) \
131: (((tp)->t_srtt >> TCP_RTT_SHIFT) + (tp)->t_rttvar)
132:
133: /* XXX
134: * We want to avoid doing m_pullup on incoming packets but that
135: * means avoiding dtom on the tcp reassembly code. That in turn means
136: * keeping an mbuf pointer in the reassembly queue (since we might
137: * have a cluster). As a quick hack, the source & destination
138: * port numbers (which are no longer needed once we've located the
139: * tcpcb) are overlayed with an mbuf pointer.
140: */
141: #define REASS_MBUF(ti) (*(struct mbuf **)&((ti)->ti_t))
142:
143: /*
144: * TCP statistics.
145: * Many of these should be kept per connection,
146: * but that's inconvenient at the moment.
147: */
148: struct tcpstat {
149: u_long tcps_connattempt; /* connections initiated */
150: u_long tcps_accepts; /* connections accepted */
151: u_long tcps_connects; /* connections established */
152: u_long tcps_drops; /* connections dropped */
153: u_long tcps_conndrops; /* embryonic connections dropped */
154: u_long tcps_closed; /* conn. closed (includes drops) */
155: u_long tcps_segstimed; /* segs where we tried to get rtt */
156: u_long tcps_rttupdated; /* times we succeeded */
157: u_long tcps_delack; /* delayed acks sent */
158: u_long tcps_timeoutdrop; /* conn. dropped in rxmt timeout */
159: u_long tcps_rexmttimeo; /* retransmit timeouts */
160: u_long tcps_persisttimeo; /* persist timeouts */
161: u_long tcps_keeptimeo; /* keepalive timeouts */
162: u_long tcps_keepprobe; /* keepalive probes sent */
163: u_long tcps_keepdrops; /* connections dropped in keepalive */
164:
165: u_long tcps_sndtotal; /* total packets sent */
166: u_long tcps_sndpack; /* data packets sent */
167: u_long tcps_sndbyte; /* data bytes sent */
168: u_long tcps_sndrexmitpack; /* data packets retransmitted */
169: u_long tcps_sndrexmitbyte; /* data bytes retransmitted */
170: u_long tcps_sndacks; /* ack-only packets sent */
171: u_long tcps_sndprobe; /* window probes sent */
172: u_long tcps_sndurg; /* packets sent with URG only */
173: u_long tcps_sndwinup; /* window update-only packets sent */
174: u_long tcps_sndctrl; /* control (SYN|FIN|RST) packets sent */
175:
176: u_long tcps_rcvtotal; /* total packets received */
177: u_long tcps_rcvpack; /* packets received in sequence */
178: u_long tcps_rcvbyte; /* bytes received in sequence */
179: u_long tcps_rcvbadsum; /* packets received with ccksum errs */
180: u_long tcps_rcvbadoff; /* packets received with bad offset */
181: u_long tcps_rcvshort; /* packets received too short */
182: u_long tcps_rcvduppack; /* duplicate-only packets received */
183: u_long tcps_rcvdupbyte; /* duplicate-only bytes received */
184: u_long tcps_rcvpartduppack; /* packets with some duplicate data */
185: u_long tcps_rcvpartdupbyte; /* dup. bytes in part-dup. packets */
186: u_long tcps_rcvoopack; /* out-of-order packets received */
187: u_long tcps_rcvoobyte; /* out-of-order bytes received */
188: u_long tcps_rcvpackafterwin; /* packets with data after window */
189: u_long tcps_rcvbyteafterwin; /* bytes rcvd after window */
190: u_long tcps_rcvafterclose; /* packets rcvd after "close" */
191: u_long tcps_rcvwinprobe; /* rcvd window probe packets */
192: u_long tcps_rcvdupack; /* rcvd duplicate acks */
193: u_long tcps_rcvacktoomuch; /* rcvd acks for unsent data */
194: u_long tcps_rcvackpack; /* rcvd ack packets */
195: u_long tcps_rcvackbyte; /* bytes acked by rcvd acks */
196: u_long tcps_rcvwinupd; /* rcvd window update packets */
197: };
198:
199: #ifdef KERNEL
200: struct inpcb tcb; /* head of queue of active tcpcb's */
201: struct tcpstat tcpstat; /* tcp statistics */
202: struct tcpiphdr *tcp_template();
203: struct tcpcb *tcp_close(), *tcp_drop();
204: struct tcpcb *tcp_timers(), *tcp_disconnect(), *tcp_usrclosed();
205: #endif
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