tcp_var.h revision 1.5
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 * from: @(#)tcp_var.h 7.10 (Berkeley) 6/28/90 34 * $Id: tcp_var.h,v 1.5 1994/01/08 23:07:24 mycroft Exp $ 35 */ 36 37 #ifndef _NETINET_TCP_VAR_H_ 38 #define _NETINET_TCP_VAR_H_ 39 40 /* 41 * Kernel variables for tcp. 42 */ 43 44 /* 45 * Tcp control block, one per tcp; fields: 46 */ 47 struct 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 */ 165 struct 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 217 struct inpcb tcb; /* head of queue of active tcpcb's */ 218 struct tcpstat tcpstat; /* tcp statistics */ 219 struct tcpiphdr *tcp_template(); 220 struct tcpcb *tcp_close(), *tcp_drop(); 221 struct tcpcb *tcp_timers(), *tcp_disconnect(), *tcp_usrclosed(); 222 223 int tcp_attach __P((struct socket *)); 224 void tcp_canceltimers __P((struct tcpcb *)); 225 struct tcpcb * 226 tcp_close __P((struct tcpcb *)); 227 void tcp_ctlinput __P((int, struct sockaddr *, struct ip *)); 228 int tcp_ctloutput 229 __P((int, struct socket *, int, int, struct mbuf **)); 230 struct tcpcb * 231 tcp_disconnect __P((struct tcpcb *)); 232 void tcp_dooptions __P((struct tcpcb *, struct mbuf *, struct tcpiphdr *)); 233 void tcp_drain __P((void)); 234 struct tcpcb * 235 tcp_drop __P((struct tcpcb *, int)); 236 void tcp_fasttimo __P((void)); 237 void tcp_init __P((void)); 238 void tcp_input __P((struct mbuf *, int)); 239 int tcp_mss __P((struct tcpcb *, u_short)); 240 struct tcpcb * 241 tcp_newtcpcb __P((struct inpcb *)); 242 void tcp_notify __P((struct inpcb *, int)); 243 int tcp_output __P((struct tcpcb *)); 244 void tcp_pulloutofband 245 __P((struct socket *, struct tcpiphdr *, struct mbuf *)); 246 void tcp_quench __P((struct inpcb *, int)); 247 int tcp_reass __P((struct tcpcb *, struct tcpiphdr *, struct mbuf *)); 248 void tcp_respond 249 __P((struct tcpcb *, struct tcpiphdr *, struct mbuf *, tcp_seq, 250 tcp_seq, int)); 251 void tcp_setpersist __P((struct tcpcb *)); 252 void tcp_slowtimo __P((void)); 253 struct tcpiphdr * 254 tcp_template __P((struct tcpcb *)); 255 struct tcpcb * 256 tcp_timers __P((struct tcpcb *, int)); 257 void tcp_trace __P((short, short, struct tcpcb *, struct tcpiphdr *, int)); 258 struct tcpcb * 259 tcp_usrclosed __P((struct tcpcb *)); 260 int tcp_usrreq 261 __P((struct socket *, int, struct mbuf *, struct mbuf *, 262 struct mbuf *)); 263 void tcp_xmit_timer __P((struct tcpcb *)); 264 #endif 265 266 #endif /* !_NETINET_TCP_VAR_H_ */ 267
Indexes created Mon Sep 22 13:09:51 GMT 2025