tcp_var.h revision 1.20
1 /* $NetBSD: tcp_var.h,v 1.20 1997/07/23 21:26:54 thorpej Exp $ */ 2 3 /* 4 * Copyright (c) 1982, 1986, 1993, 1994 5 * The Regents of the University of California. All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 3. All advertising materials mentioning features or use of this software 16 * must display the following acknowledgement: 17 * This product includes software developed by the University of 18 * California, Berkeley and its contributors. 19 * 4. Neither the name of the University nor the names of its contributors 20 * may be used to endorse or promote products derived from this software 21 * without specific prior written permission. 22 * 23 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 24 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 25 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 26 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 27 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 28 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 29 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 30 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 31 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 32 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 33 * SUCH DAMAGE. 34 * 35 * @(#)tcp_var.h 8.3 (Berkeley) 4/10/94 36 */ 37 38 /* 39 * Kernel variables for tcp. 40 */ 41 42 /* 43 * Tcp control block, one per tcp; fields: 44 */ 45 struct tcpcb { 46 struct ipqehead segq; /* sequencing queue */ 47 short t_state; /* state of this connection */ 48 short t_timer[TCPT_NTIMERS]; /* tcp timers */ 49 short t_rxtshift; /* log(2) of rexmt exp. backoff */ 50 short t_rxtcur; /* current retransmit value */ 51 short t_dupacks; /* consecutive dup acks recd */ 52 u_short t_maxseg; /* maximum segment size */ 53 char t_force; /* 1 if forcing out a byte */ 54 u_short t_flags; 55 #define TF_ACKNOW 0x0001 /* ack peer immediately */ 56 #define TF_DELACK 0x0002 /* ack, but try to delay it */ 57 #define TF_NODELAY 0x0004 /* don't delay packets to coalesce */ 58 #define TF_NOOPT 0x0008 /* don't use tcp options */ 59 #define TF_SENTFIN 0x0010 /* have sent FIN */ 60 #define TF_REQ_SCALE 0x0020 /* have/will request window scaling */ 61 #define TF_RCVD_SCALE 0x0040 /* other side has requested scaling */ 62 #define TF_REQ_TSTMP 0x0080 /* have/will request timestamps */ 63 #define TF_RCVD_TSTMP 0x0100 /* a timestamp was received in SYN */ 64 #define TF_SACK_PERMIT 0x0200 /* other side said I could SACK */ 65 66 struct tcpiphdr *t_template; /* skeletal packet for transmit */ 67 struct inpcb *t_inpcb; /* back pointer to internet pcb */ 68 /* 69 * The following fields are used as in the protocol specification. 70 * See RFC783, Dec. 1981, page 21. 71 */ 72 /* send sequence variables */ 73 tcp_seq snd_una; /* send unacknowledged */ 74 tcp_seq snd_nxt; /* send next */ 75 tcp_seq snd_up; /* send urgent pointer */ 76 tcp_seq snd_wl1; /* window update seg seq number */ 77 tcp_seq snd_wl2; /* window update seg ack number */ 78 tcp_seq iss; /* initial send sequence number */ 79 u_long snd_wnd; /* send window */ 80 /* receive sequence variables */ 81 u_long rcv_wnd; /* receive window */ 82 tcp_seq rcv_nxt; /* receive next */ 83 tcp_seq rcv_up; /* receive urgent pointer */ 84 tcp_seq irs; /* initial receive sequence number */ 85 /* 86 * Additional variables for this implementation. 87 */ 88 /* receive variables */ 89 tcp_seq rcv_adv; /* advertised window */ 90 /* retransmit variables */ 91 tcp_seq snd_max; /* highest sequence number sent; 92 * used to recognize retransmits 93 */ 94 /* congestion control (for slow start, source quench, retransmit after loss) */ 95 u_long snd_cwnd; /* congestion-controlled window */ 96 u_long snd_ssthresh; /* snd_cwnd size threshhold for 97 * for slow start exponential to 98 * linear switch 99 */ 100 /* 101 * transmit timing stuff. See below for scale of srtt and rttvar. 102 * "Variance" is actually smoothed difference. 103 */ 104 short t_idle; /* inactivity time */ 105 short t_rtt; /* round trip time */ 106 tcp_seq t_rtseq; /* sequence number being timed */ 107 short t_srtt; /* smoothed round-trip time */ 108 short t_rttvar; /* variance in round-trip time */ 109 u_short t_rttmin; /* minimum rtt allowed */ 110 u_long max_sndwnd; /* largest window peer has offered */ 111 112 /* out-of-band data */ 113 char t_oobflags; /* have some */ 114 char t_iobc; /* input character */ 115 #define TCPOOB_HAVEDATA 0x01 116 #define TCPOOB_HADDATA 0x02 117 short t_softerror; /* possible error not yet reported */ 118 119 /* RFC 1323 variables */ 120 u_char snd_scale; /* window scaling for send window */ 121 u_char rcv_scale; /* window scaling for recv window */ 122 u_char request_r_scale; /* pending window scaling */ 123 u_char requested_s_scale; 124 u_int32_t ts_recent; /* timestamp echo data */ 125 u_int32_t ts_recent_age; /* when last updated */ 126 tcp_seq last_ack_sent; 127 128 /* TUBA stuff */ 129 caddr_t t_tuba_pcb; /* next level down pcb for TCP over z */ 130 }; 131 132 /* 133 * Handy way of passing around TCP option info. 134 */ 135 struct tcp_opt_info { 136 int ts_present; 137 u_int32_t ts_val; 138 u_int32_t ts_ecr; 139 u_int16_t maxseg; 140 }; 141 142 /* 143 * This structure should not exceed 32 bytes. 144 * XXX On the Alpha, it's already 36-bytes, which rounds to 40. 145 * XXX Need to eliminate the pointer. 146 */ 147 struct syn_cache { 148 struct syn_cache *sc_next; 149 u_int32_t sc_tstmp : 1, 150 sc_hash : 31; 151 struct in_addr sc_src; 152 struct in_addr sc_dst; 153 tcp_seq sc_irs; 154 tcp_seq sc_iss; 155 u_int16_t sc_sport; 156 u_int16_t sc_dport; 157 u_int16_t sc_peermaxseg; 158 u_int8_t sc_timer; 159 u_int8_t sc_request_r_scale : 4, 160 sc_requested_s_scale : 4; 161 }; 162 163 struct syn_cache_head { 164 struct syn_cache *sch_first; /* First entry in the bucket */ 165 struct syn_cache *sch_last; /* Last entry in the bucket */ 166 struct syn_cache_head *sch_headq; /* The next non-empty bucket */ 167 int16_t sch_timer_sum; /* Total time in this bucket */ 168 u_int16_t sch_length; /* @ # elements in bucket */ 169 }; 170 171 #define intotcpcb(ip) ((struct tcpcb *)(ip)->inp_ppcb) 172 #define sototcpcb(so) (intotcpcb(sotoinpcb(so))) 173 174 /* 175 * The smoothed round-trip time and estimated variance 176 * are stored as fixed point numbers scaled by the values below. 177 * For convenience, these scales are also used in smoothing the average 178 * (smoothed = (1/scale)sample + ((scale-1)/scale)smoothed). 179 * With these scales, srtt has 3 bits to the right of the binary point, 180 * and thus an "ALPHA" of 0.875. rttvar has 2 bits to the right of the 181 * binary point, and is smoothed with an ALPHA of 0.75. 182 */ 183 #define TCP_RTT_SHIFT 3 /* shift for srtt; 3 bits frac. */ 184 #define TCP_RTTVAR_SHIFT 2 /* multiplier for rttvar; 2 bits */ 185 186 /* 187 * The initial retransmission should happen at rtt + 4 * rttvar. 188 * Because of the way we do the smoothing, srtt and rttvar 189 * will each average +1/2 tick of bias. When we compute 190 * the retransmit timer, we want 1/2 tick of rounding and 191 * 1 extra tick because of +-1/2 tick uncertainty in the 192 * firing of the timer. The bias will give us exactly the 193 * 1.5 tick we need. But, because the bias is 194 * statistical, we have to test that we don't drop below 195 * the minimum feasible timer (which is 2 ticks). 196 * This macro assumes that the value of 1<<TCP_RTTVAR_SHIFT 197 * is the same as the multiplier for rttvar. 198 */ 199 #define TCP_REXMTVAL(tp) \ 200 ((((tp)->t_srtt >> TCP_RTT_SHIFT) + (tp)->t_rttvar) >> 2) 201 202 /* 203 * TCP statistics. 204 * Many of these should be kept per connection, 205 * but that's inconvenient at the moment. 206 */ 207 struct tcpstat { 208 u_long tcps_connattempt; /* connections initiated */ 209 u_long tcps_accepts; /* connections accepted */ 210 u_long tcps_connects; /* connections established */ 211 u_long tcps_drops; /* connections dropped */ 212 u_long tcps_conndrops; /* embryonic connections dropped */ 213 u_long tcps_closed; /* conn. closed (includes drops) */ 214 u_long tcps_segstimed; /* segs where we tried to get rtt */ 215 u_long tcps_rttupdated; /* times we succeeded */ 216 u_long tcps_delack; /* delayed acks sent */ 217 u_long tcps_timeoutdrop; /* conn. dropped in rxmt timeout */ 218 u_long tcps_rexmttimeo; /* retransmit timeouts */ 219 u_long tcps_persisttimeo; /* persist timeouts */ 220 u_long tcps_keeptimeo; /* keepalive timeouts */ 221 u_long tcps_keepprobe; /* keepalive probes sent */ 222 u_long tcps_keepdrops; /* connections dropped in keepalive */ 223 224 u_long tcps_sndtotal; /* total packets sent */ 225 u_long tcps_sndpack; /* data packets sent */ 226 u_long tcps_sndbyte; /* data bytes sent */ 227 u_long tcps_sndrexmitpack; /* data packets retransmitted */ 228 u_long tcps_sndrexmitbyte; /* data bytes retransmitted */ 229 u_long tcps_sndacks; /* ack-only packets sent */ 230 u_long tcps_sndprobe; /* window probes sent */ 231 u_long tcps_sndurg; /* packets sent with URG only */ 232 u_long tcps_sndwinup; /* window update-only packets sent */ 233 u_long tcps_sndctrl; /* control (SYN|FIN|RST) packets sent */ 234 235 u_long tcps_rcvtotal; /* total packets received */ 236 u_long tcps_rcvpack; /* packets received in sequence */ 237 u_long tcps_rcvbyte; /* bytes received in sequence */ 238 u_long tcps_rcvbadsum; /* packets received with ccksum errs */ 239 u_long tcps_rcvbadoff; /* packets received with bad offset */ 240 u_long tcps_rcvmemdrop; /* packets dropped for lack of memory */ 241 u_long tcps_rcvshort; /* packets received too short */ 242 u_long tcps_rcvduppack; /* duplicate-only packets received */ 243 u_long tcps_rcvdupbyte; /* duplicate-only bytes received */ 244 u_long tcps_rcvpartduppack; /* packets with some duplicate data */ 245 u_long tcps_rcvpartdupbyte; /* dup. bytes in part-dup. packets */ 246 u_long tcps_rcvoopack; /* out-of-order packets received */ 247 u_long tcps_rcvoobyte; /* out-of-order bytes received */ 248 u_long tcps_rcvpackafterwin; /* packets with data after window */ 249 u_long tcps_rcvbyteafterwin; /* bytes rcvd after window */ 250 u_long tcps_rcvafterclose; /* packets rcvd after "close" */ 251 u_long tcps_rcvwinprobe; /* rcvd window probe packets */ 252 u_long tcps_rcvdupack; /* rcvd duplicate acks */ 253 u_long tcps_rcvacktoomuch; /* rcvd acks for unsent data */ 254 u_long tcps_rcvackpack; /* rcvd ack packets */ 255 u_long tcps_rcvackbyte; /* bytes acked by rcvd acks */ 256 u_long tcps_rcvwinupd; /* rcvd window update packets */ 257 u_long tcps_pawsdrop; /* segments dropped due to PAWS */ 258 u_long tcps_predack; /* times hdr predict ok for acks */ 259 u_long tcps_preddat; /* times hdr predict ok for data pkts */ 260 261 u_long tcps_pcbhashmiss; /* input packets missing pcb hash */ 262 u_long tcps_noport; /* no socket on port */ 263 u_long tcps_badsyn; /* received ack for which we have 264 no SYN in compressed state */ 265 266 /* These statistics deal with the SYN cache. */ 267 u_long tcps_sc_added; /* # of entries added */ 268 u_long tcps_sc_completed; /* # of connections completed */ 269 u_long tcps_sc_timed_out; /* # of entries timed out */ 270 u_long tcps_sc_overflowed; /* # dropped due to overflow */ 271 u_long tcps_sc_reset; /* # dropped due to RST */ 272 u_long tcps_sc_unreach; /* # dropped due to ICMP unreach */ 273 u_long tcps_sc_bucketoverflow; /* # dropped due to bucket overflow */ 274 u_long tcps_sc_aborted; /* # of entries aborted (no mem) */ 275 u_long tcps_sc_dupesyn; /* # of duplicate SYNs received */ 276 u_long tcps_sc_dropped; /* # of SYNs dropped (no route/mem) */ 277 u_long tcps_sc_collisions; /* # of hash collisions */ 278 }; 279 280 /* 281 * Names for TCP sysctl objects. 282 */ 283 /* enable/disable RFC1323 timestamps/scaling */ 284 #define TCPCTL_RFC1323 1 285 #define TCPCTL_MAXID 2 286 287 #define TCPCTL_NAMES { \ 288 { 0, 0 }, \ 289 { "rfc1323", CTLTYPE_INT }, \ 290 } 291 292 #ifdef _KERNEL 293 struct inpcbtable tcbtable; /* head of queue of active tcpcb's */ 294 struct tcpstat tcpstat; /* tcp statistics */ 295 u_int32_t tcp_now; /* for RFC 1323 timestamps */ 296 extern int tcp_do_rfc1323; /* enabled/disabled? */ 297 298 int tcp_syn_cache_size; 299 int tcp_syn_cache_timeo; 300 struct syn_cache_head tcp_syn_cache[], *tcp_syn_cache_first; 301 u_long syn_cache_count; 302 303 int tcp_attach __P((struct socket *)); 304 void tcp_canceltimers __P((struct tcpcb *)); 305 struct tcpcb * 306 tcp_close __P((struct tcpcb *)); 307 void *tcp_ctlinput __P((int, struct sockaddr *, void *)); 308 int tcp_ctloutput __P((int, struct socket *, int, int, struct mbuf **)); 309 struct tcpcb * 310 tcp_disconnect __P((struct tcpcb *)); 311 struct tcpcb * 312 tcp_drop __P((struct tcpcb *, int)); 313 void tcp_dooptions __P((struct tcpcb *, 314 u_char *, int, struct tcpiphdr *, struct tcp_opt_info *)); 315 void tcp_drain __P((void)); 316 void tcp_fasttimo __P((void)); 317 void tcp_init __P((void)); 318 void tcp_input __P((struct mbuf *, ...)); 319 int tcp_mss __P((struct tcpcb *, u_int)); 320 struct tcpcb * 321 tcp_newtcpcb __P((struct inpcb *)); 322 void tcp_notify __P((struct inpcb *, int)); 323 int tcp_output __P((struct tcpcb *)); 324 void tcp_pulloutofband __P((struct socket *, 325 struct tcpiphdr *, struct mbuf *)); 326 void tcp_quench __P((struct inpcb *, int)); 327 int tcp_reass __P((struct tcpcb *, struct tcpiphdr *, struct mbuf *)); 328 int tcp_respond __P((struct tcpcb *, 329 struct tcpiphdr *, struct mbuf *, tcp_seq, tcp_seq, int)); 330 void tcp_setpersist __P((struct tcpcb *)); 331 void tcp_slowtimo __P((void)); 332 struct tcpiphdr * 333 tcp_template __P((struct tcpcb *)); 334 struct tcpcb * 335 tcp_timers __P((struct tcpcb *, int)); 336 void tcp_trace __P((int, int, struct tcpcb *, struct tcpiphdr *, int)); 337 struct tcpcb * 338 tcp_usrclosed __P((struct tcpcb *)); 339 int tcp_sysctl __P((int *, u_int, void *, size_t *, void *, size_t)); 340 int tcp_usrreq __P((struct socket *, 341 int, struct mbuf *, struct mbuf *, struct mbuf *, struct proc *)); 342 void tcp_xmit_timer __P((struct tcpcb *, int)); 343 344 int syn_cache_add __P((struct socket *, struct mbuf *, u_char *, 345 int, struct tcp_opt_info *)); 346 void syn_cache_unreach __P((struct ip *, struct tcphdr *)); 347 struct socket * 348 syn_cache_get __P((struct socket *so, struct mbuf *)); 349 void syn_cache_insert __P((struct syn_cache *, struct syn_cache ***, 350 struct syn_cache_head **)); 351 struct syn_cache * 352 syn_cache_lookup __P((struct tcpiphdr *, struct syn_cache ***, 353 struct syn_cache_head **)); 354 void syn_cache_reset __P((struct tcpiphdr *)); 355 int syn_cache_respond __P((struct syn_cache *, struct mbuf *, 356 register struct tcpiphdr *, long, u_long)); 357 void syn_cache_timer __P((int)); 358 359 #endif 360
Indexes created Tue Sep 23 23:09:58 GMT 2025