tcp_var.h revision 2169
1/* 2 * Copyright (c) 1982, 1986, 1993, 1994 3 * The Regents of the University of California. 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 8.3 (Berkeley) 4/10/94 34 * $Id: tcp_var.h,v 1.2 1994/08/02 07:49:17 davidg Exp $ 35 */ 36 37#ifndef _NETINET_TCP_VAR_H_ 38#define _NETINET_TCP_VAR_H_ 39/* 40 * Kernel variables for tcp. 41 */ 42 43/* 44 * Tcp control block, one per tcp; fields: 45 */ 46struct tcpcb { 47 struct tcpiphdr *seg_next; /* sequencing queue */ 48 struct tcpiphdr *seg_prev; 49 short t_state; /* state of this connection */ 50 short t_timer[TCPT_NTIMERS]; /* tcp timers */ 51 short t_rxtshift; /* log(2) of rexmt exp. backoff */ 52 short t_rxtcur; /* current retransmit value */ 53 short t_dupacks; /* consecutive dup acks recd */ 54 u_short t_maxseg; /* maximum segment size */ 55 char t_force; /* 1 if forcing out a byte */ 56 u_short t_flags; 57#define TF_ACKNOW 0x0001 /* ack peer immediately */ 58#define TF_DELACK 0x0002 /* ack, but try to delay it */ 59#define TF_NODELAY 0x0004 /* don't delay packets to coalesce */ 60#define TF_NOOPT 0x0008 /* don't use tcp options */ 61#define TF_SENTFIN 0x0010 /* have sent FIN */ 62#define TF_REQ_SCALE 0x0020 /* have/will request window scaling */ 63#define TF_RCVD_SCALE 0x0040 /* other side has requested scaling */ 64#define TF_REQ_TSTMP 0x0080 /* have/will request timestamps */ 65#define TF_RCVD_TSTMP 0x0100 /* a timestamp was received in SYN */ 66#define TF_SACK_PERMIT 0x0200 /* other side said I could SACK */ 67 68 struct tcpiphdr *t_template; /* skeletal packet for transmit */ 69 struct inpcb *t_inpcb; /* back pointer to internet pcb */ 70/* 71 * The following fields are used as in the protocol specification. 72 * See RFC783, Dec. 1981, page 21. 73 */ 74/* send sequence variables */ 75 tcp_seq snd_una; /* send unacknowledged */ 76 tcp_seq snd_nxt; /* send next */ 77 tcp_seq snd_up; /* send urgent pointer */ 78 tcp_seq snd_wl1; /* window update seg seq number */ 79 tcp_seq snd_wl2; /* window update seg ack number */ 80 tcp_seq iss; /* initial send sequence number */ 81 u_long snd_wnd; /* send window */ 82/* receive sequence variables */ 83 u_long rcv_wnd; /* receive window */ 84 tcp_seq rcv_nxt; /* receive next */ 85 tcp_seq rcv_up; /* receive urgent pointer */ 86 tcp_seq irs; /* initial receive sequence number */ 87/* 88 * Additional variables for this implementation. 89 */ 90/* receive variables */ 91 tcp_seq rcv_adv; /* advertised window */ 92/* retransmit variables */ 93 tcp_seq snd_max; /* highest sequence number sent; 94 * used to recognize retransmits 95 */ 96/* congestion control (for slow start, source quench, retransmit after loss) */ 97 u_long snd_cwnd; /* congestion-controlled window */ 98 u_long snd_ssthresh; /* snd_cwnd size threshhold for 99 * for slow start exponential to 100 * linear switch 101 */ 102/* 103 * transmit timing stuff. See below for scale of srtt and rttvar. 104 * "Variance" is actually smoothed difference. 105 */ 106 short t_idle; /* inactivity time */ 107 short t_rtt; /* round trip time */ 108 tcp_seq t_rtseq; /* sequence number being timed */ 109 short t_srtt; /* smoothed round-trip time */ 110 short t_rttvar; /* variance in round-trip time */ 111 u_short t_rttmin; /* minimum rtt allowed */ 112 u_long max_sndwnd; /* largest window peer has offered */ 113 114/* out-of-band data */ 115 char t_oobflags; /* have some */ 116 char t_iobc; /* input character */ 117#define TCPOOB_HAVEDATA 0x01 118#define TCPOOB_HADDATA 0x02 119 short t_softerror; /* possible error not yet reported */ 120 121/* RFC 1323 variables */ 122 u_char snd_scale; /* window scaling for send window */ 123 u_char rcv_scale; /* window scaling for recv window */ 124 u_char request_r_scale; /* pending window scaling */ 125 u_char requested_s_scale; 126 u_long ts_recent; /* timestamp echo data */ 127 u_long ts_recent_age; /* when last updated */ 128 tcp_seq last_ack_sent; 129 130/* TUBA stuff */ 131 caddr_t t_tuba_pcb; /* next level down pcb for TCP over z */ 132}; 133 134#define intotcpcb(ip) ((struct tcpcb *)(ip)->inp_ppcb) 135#define sototcpcb(so) (intotcpcb(sotoinpcb(so))) 136 137/* 138 * The smoothed round-trip time and estimated variance 139 * are stored as fixed point numbers scaled by the values below. 140 * For convenience, these scales are also used in smoothing the average 141 * (smoothed = (1/scale)sample + ((scale-1)/scale)smoothed). 142 * With these scales, srtt has 3 bits to the right of the binary point, 143 * and thus an "ALPHA" of 0.875. rttvar has 2 bits to the right of the 144 * binary point, and is smoothed with an ALPHA of 0.75. 145 */ 146#define TCP_RTT_SCALE 8 /* multiplier for srtt; 3 bits frac. */ 147#define TCP_RTT_SHIFT 3 /* shift for srtt; 3 bits frac. */ 148#define TCP_RTTVAR_SCALE 4 /* multiplier for rttvar; 2 bits */ 149#define TCP_RTTVAR_SHIFT 2 /* multiplier for rttvar; 2 bits */ 150 151/* 152 * The initial retransmission should happen at rtt + 4 * rttvar. 153 * Because of the way we do the smoothing, srtt and rttvar 154 * will each average +1/2 tick of bias. When we compute 155 * the retransmit timer, we want 1/2 tick of rounding and 156 * 1 extra tick because of +-1/2 tick uncertainty in the 157 * firing of the timer. The bias will give us exactly the 158 * 1.5 tick we need. But, because the bias is 159 * statistical, we have to test that we don't drop below 160 * the minimum feasible timer (which is 2 ticks). 161 * This macro assumes that the value of TCP_RTTVAR_SCALE 162 * is the same as the multiplier for rttvar. 163 */ 164#define TCP_REXMTVAL(tp) \ 165 (((tp)->t_srtt >> TCP_RTT_SHIFT) + (tp)->t_rttvar) 166 167/* XXX 168 * We want to avoid doing m_pullup on incoming packets but that 169 * means avoiding dtom on the tcp reassembly code. That in turn means 170 * keeping an mbuf pointer in the reassembly queue (since we might 171 * have a cluster). As a quick hack, the source & destination 172 * port numbers (which are no longer needed once we've located the 173 * tcpcb) are overlayed with an mbuf pointer. 174 */ 175#define REASS_MBUF(ti) (*(struct mbuf **)&((ti)->ti_t)) 176 177/* 178 * TCP statistics. 179 * Many of these should be kept per connection, 180 * but that's inconvenient at the moment. 181 */ 182struct tcpstat { 183 u_long tcps_connattempt; /* connections initiated */ 184 u_long tcps_accepts; /* connections accepted */ 185 u_long tcps_connects; /* connections established */ 186 u_long tcps_drops; /* connections dropped */ 187 u_long tcps_conndrops; /* embryonic connections dropped */ 188 u_long tcps_closed; /* conn. closed (includes drops) */ 189 u_long tcps_segstimed; /* segs where we tried to get rtt */ 190 u_long tcps_rttupdated; /* times we succeeded */ 191 u_long tcps_delack; /* delayed acks sent */ 192 u_long tcps_timeoutdrop; /* conn. dropped in rxmt timeout */ 193 u_long tcps_rexmttimeo; /* retransmit timeouts */ 194 u_long tcps_persisttimeo; /* persist timeouts */ 195 u_long tcps_keeptimeo; /* keepalive timeouts */ 196 u_long tcps_keepprobe; /* keepalive probes sent */ 197 u_long tcps_keepdrops; /* connections dropped in keepalive */ 198 199 u_long tcps_sndtotal; /* total packets sent */ 200 u_long tcps_sndpack; /* data packets sent */ 201 u_long tcps_sndbyte; /* data bytes sent */ 202 u_long tcps_sndrexmitpack; /* data packets retransmitted */ 203 u_long tcps_sndrexmitbyte; /* data bytes retransmitted */ 204 u_long tcps_sndacks; /* ack-only packets sent */ 205 u_long tcps_sndprobe; /* window probes sent */ 206 u_long tcps_sndurg; /* packets sent with URG only */ 207 u_long tcps_sndwinup; /* window update-only packets sent */ 208 u_long tcps_sndctrl; /* control (SYN|FIN|RST) packets sent */ 209 210 u_long tcps_rcvtotal; /* total packets received */ 211 u_long tcps_rcvpack; /* packets received in sequence */ 212 u_long tcps_rcvbyte; /* bytes received in sequence */ 213 u_long tcps_rcvbadsum; /* packets received with ccksum errs */ 214 u_long tcps_rcvbadoff; /* packets received with bad offset */ 215 u_long tcps_rcvshort; /* packets received too short */ 216 u_long tcps_rcvduppack; /* duplicate-only packets received */ 217 u_long tcps_rcvdupbyte; /* duplicate-only bytes received */ 218 u_long tcps_rcvpartduppack; /* packets with some duplicate data */ 219 u_long tcps_rcvpartdupbyte; /* dup. bytes in part-dup. packets */ 220 u_long tcps_rcvoopack; /* out-of-order packets received */ 221 u_long tcps_rcvoobyte; /* out-of-order bytes received */ 222 u_long tcps_rcvpackafterwin; /* packets with data after window */ 223 u_long tcps_rcvbyteafterwin; /* bytes rcvd after window */ 224 u_long tcps_rcvafterclose; /* packets rcvd after "close" */ 225 u_long tcps_rcvwinprobe; /* rcvd window probe packets */ 226 u_long tcps_rcvdupack; /* rcvd duplicate acks */ 227 u_long tcps_rcvacktoomuch; /* rcvd acks for unsent data */ 228 u_long tcps_rcvackpack; /* rcvd ack packets */ 229 u_long tcps_rcvackbyte; /* bytes acked by rcvd acks */ 230 u_long tcps_rcvwinupd; /* rcvd window update packets */ 231 u_long tcps_pawsdrop; /* segments dropped due to PAWS */ 232 u_long tcps_predack; /* times hdr predict ok for acks */ 233 u_long tcps_preddat; /* times hdr predict ok for data pkts */ 234 u_long tcps_pcbcachemiss; 235}; 236 237#ifdef KERNEL 238struct inpcb tcb; /* head of queue of active tcpcb's */ 239struct tcpstat tcpstat; /* tcp statistics */ 240u_long tcp_now; /* for RFC 1323 timestamps */ 241 242int tcp_attach __P((struct socket *)); 243void tcp_canceltimers __P((struct tcpcb *)); 244struct tcpcb * 245 tcp_close __P((struct tcpcb *)); 246void tcp_ctlinput __P((int, struct sockaddr *, struct ip *)); 247int tcp_ctloutput __P((int, struct socket *, int, int, struct mbuf **)); 248struct tcpcb * 249 tcp_disconnect __P((struct tcpcb *)); 250struct tcpcb * 251 tcp_drop __P((struct tcpcb *, int)); 252void tcp_dooptions __P((struct tcpcb *, 253 u_char *, int, struct tcpiphdr *, int *, u_long *, u_long *)); 254void tcp_drain __P((void)); 255void tcp_fasttimo __P((void)); 256void tcp_init __P((void)); 257void tcp_input __P((struct mbuf *, int)); 258int tcp_mss __P((struct tcpcb *, u_int)); 259struct tcpcb * 260 tcp_newtcpcb __P((struct inpcb *)); 261void tcp_notify __P((struct inpcb *, int)); 262int tcp_output __P((struct tcpcb *)); 263void tcp_pulloutofband __P((struct socket *, 264 struct tcpiphdr *, struct mbuf *)); 265void tcp_quench __P((struct inpcb *, int)); 266int tcp_reass __P((struct tcpcb *, struct tcpiphdr *, struct mbuf *)); 267void tcp_respond __P((struct tcpcb *, 268 struct tcpiphdr *, struct mbuf *, u_long, u_long, int)); 269void tcp_setpersist __P((struct tcpcb *)); 270void tcp_slowtimo __P((void)); 271struct tcpiphdr * 272 tcp_template __P((struct tcpcb *)); 273struct tcpcb * 274 tcp_timers __P((struct tcpcb *, int)); 275void tcp_trace __P((int, int, struct tcpcb *, struct tcpiphdr *, int)); 276struct tcpcb * 277 tcp_usrclosed __P((struct tcpcb *)); 278int tcp_usrreq __P((struct socket *, 279 int, struct mbuf *, struct mbuf *, struct mbuf *)); 280void tcp_xmit_timer __P((struct tcpcb *, int)); 281#endif 282 283#endif 284