1 /* $NetBSD: tcp_var.h,v 1.41 1998/04/13 21:18:20 kml Exp $ */ 2 3 /*- 4 * Copyright (c) 1997, 1998 The NetBSD Foundation, Inc. 5 * All rights reserved. 6 * 7 * This code is derived from software contributed to The NetBSD Foundation 8 * by Jason R. Thorpe of the Numerical Aerospace Simulation Facility, 9 * NASA Ames Research Center. 10 * 11 * Redistribution and use in source and binary forms, with or without 12 * modification, are permitted provided that the following conditions 13 * are met: 14 * 1. Redistributions of source code must retain the above copyright 15 * notice, this list of conditions and the following disclaimer. 16 * 2. Redistributions in binary form must reproduce the above copyright 17 * notice, this list of conditions and the following disclaimer in the 18 * documentation and/or other materials provided with the distribution. 19 * 3. All advertising materials mentioning features or use of this software 20 * must display the following acknowledgement: 21 * This product includes software developed by the NetBSD 22 * Foundation, Inc. and its contributors. 23 * 4. Neither the name of The NetBSD Foundation nor the names of its 24 * contributors may be used to endorse or promote products derived 25 * from this software without specific prior written permission. 26 * 27 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 28 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 29 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 30 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 31 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 32 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 33 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 34 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 35 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 36 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 37 * POSSIBILITY OF SUCH DAMAGE. 38 */ 39 40 /* 41 * Copyright (c) 1982, 1986, 1993, 1994, 1995 42 * The Regents of the University of California. All rights reserved. 43 * 44 * Redistribution and use in source and binary forms, with or without 45 * modification, are permitted provided that the following conditions 46 * are met: 47 * 1. Redistributions of source code must retain the above copyright 48 * notice, this list of conditions and the following disclaimer. 49 * 2. Redistributions in binary form must reproduce the above copyright 50 * notice, this list of conditions and the following disclaimer in the 51 * documentation and/or other materials provided with the distribution. 52 * 3. All advertising materials mentioning features or use of this software 53 * must display the following acknowledgement: 54 * This product includes software developed by the University of 55 * California, Berkeley and its contributors. 56 * 4. Neither the name of the University nor the names of its contributors 57 * may be used to endorse or promote products derived from this software 58 * without specific prior written permission. 59 * 60 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 61 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 62 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 63 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 64 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 65 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 66 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 67 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 68 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 69 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 70 * SUCH DAMAGE. 71 * 72 * @(#)tcp_var.h 8.4 (Berkeley) 5/24/95 73 */ 74 75 #ifndef _NETINET_TCP_VAR_H_ 76 #define _NETINET_TCP_VAR_H_ 77 78 /* 79 * Kernel variables for tcp. 80 */ 81 82 /* 83 * Tcp control block, one per tcp; fields: 84 */ 85 struct tcpcb { 86 struct ipqehead segq; /* sequencing queue */ 87 short t_state; /* state of this connection */ 88 short t_timer[TCPT_NTIMERS]; /* tcp timers */ 89 short t_rxtshift; /* log(2) of rexmt exp. backoff */ 90 short t_rxtcur; /* current retransmit value */ 91 short t_dupacks; /* consecutive dup acks recd */ 92 u_short t_peermss; /* peer's maximum segment size */ 93 u_short t_ourmss; /* our's maximum segment size */ 94 u_short t_segsz; /* current segment size in use */ 95 char t_force; /* 1 if forcing out a byte */ 96 u_short t_flags; 97 #define TF_ACKNOW 0x0001 /* ack peer immediately */ 98 #define TF_DELACK 0x0002 /* ack, but try to delay it */ 99 #define TF_NODELAY 0x0004 /* don't delay packets to coalesce */ 100 #define TF_NOOPT 0x0008 /* don't use tcp options */ 101 #define TF_SENTFIN 0x0010 /* have sent FIN */ 102 #define TF_REQ_SCALE 0x0020 /* have/will request window scaling */ 103 #define TF_RCVD_SCALE 0x0040 /* other side has requested scaling */ 104 #define TF_REQ_TSTMP 0x0080 /* have/will request timestamps */ 105 #define TF_RCVD_TSTMP 0x0100 /* a timestamp was received in SYN */ 106 #define TF_SACK_PERMIT 0x0200 /* other side said I could SACK */ 107 #define TF_SYN_REXMT 0x0400 /* rexmit timer fired on SYN */ 108 109 struct tcpiphdr *t_template; /* skeletal packet for transmit */ 110 struct inpcb *t_inpcb; /* back pointer to internet pcb */ 111 LIST_ENTRY(tcpcb) t_delack; /* delayed ACK queue */ 112 /* 113 * The following fields are used as in the protocol specification. 114 * See RFC783, Dec. 1981, page 21. 115 */ 116 /* send sequence variables */ 117 tcp_seq snd_una; /* send unacknowledged */ 118 tcp_seq snd_nxt; /* send next */ 119 tcp_seq snd_up; /* send urgent pointer */ 120 tcp_seq snd_wl1; /* window update seg seq number */ 121 tcp_seq snd_wl2; /* window update seg ack number */ 122 tcp_seq iss; /* initial send sequence number */ 123 u_long snd_wnd; /* send window */ 124 /* receive sequence variables */ 125 u_long rcv_wnd; /* receive window */ 126 tcp_seq rcv_nxt; /* receive next */ 127 tcp_seq rcv_up; /* receive urgent pointer */ 128 tcp_seq irs; /* initial receive sequence number */ 129 /* 130 * Additional variables for this implementation. 131 */ 132 /* receive variables */ 133 tcp_seq rcv_adv; /* advertised window */ 134 /* retransmit variables */ 135 tcp_seq snd_max; /* highest sequence number sent; 136 * used to recognize retransmits 137 */ 138 /* congestion control (for slow start, source quench, retransmit after loss) */ 139 u_long snd_cwnd; /* congestion-controlled window */ 140 u_long snd_ssthresh; /* snd_cwnd size threshhold for 141 * for slow start exponential to 142 * linear switch 143 */ 144 /* 145 * transmit timing stuff. See below for scale of srtt and rttvar. 146 * "Variance" is actually smoothed difference. 147 */ 148 short t_idle; /* inactivity time */ 149 short t_rtt; /* round trip time */ 150 tcp_seq t_rtseq; /* sequence number being timed */ 151 short t_srtt; /* smoothed round-trip time */ 152 short t_rttvar; /* variance in round-trip time */ 153 short t_rttmin; /* minimum rtt allowed */ 154 u_long max_sndwnd; /* largest window peer has offered */ 155 156 /* out-of-band data */ 157 char t_oobflags; /* have some */ 158 char t_iobc; /* input character */ 159 #define TCPOOB_HAVEDATA 0x01 160 #define TCPOOB_HADDATA 0x02 161 short t_softerror; /* possible error not yet reported */ 162 163 /* RFC 1323 variables */ 164 u_char snd_scale; /* window scaling for send window */ 165 u_char rcv_scale; /* window scaling for recv window */ 166 u_char request_r_scale; /* pending window scaling */ 167 u_char requested_s_scale; 168 u_int32_t ts_recent; /* timestamp echo data */ 169 u_int32_t ts_recent_age; /* when last updated */ 170 tcp_seq last_ack_sent; 171 172 /* TUBA stuff */ 173 caddr_t t_tuba_pcb; /* next level down pcb for TCP over z */ 174 }; 175 176 /* 177 * Queue for delayed ACK processing. 178 */ 179 LIST_HEAD(tcp_delack_head, tcpcb); 180 #ifdef _KERNEL 181 extern struct tcp_delack_head tcp_delacks; 182 183 #define TCP_SET_DELACK(tp) \ 184 do { \ 185 if (((tp)->t_flags & TF_DELACK) == 0) { \ 186 (tp)->t_flags |= TF_DELACK; \ 187 LIST_INSERT_HEAD(&tcp_delacks, (tp), t_delack); \ 188 } \ 189 } while (0) 190 191 #define TCP_CLEAR_DELACK(tp) \ 192 do { \ 193 if ((tp)->t_flags & TF_DELACK) { \ 194 (tp)->t_flags &= ~TF_DELACK; \ 195 LIST_REMOVE((tp), t_delack); \ 196 } \ 197 } while (0) 198 #endif /* _KERNEL */ 199 200 /* 201 * Handy way of passing around TCP option info. 202 */ 203 struct tcp_opt_info { 204 int ts_present; 205 u_int32_t ts_val; 206 u_int32_t ts_ecr; 207 u_int16_t maxseg; 208 }; 209 210 /* 211 * Data for the TCP compressed state engine. 212 */ 213 struct syn_cache { 214 struct syn_cache *sc_next; 215 u_int32_t sc_hash; 216 struct in_addr sc_src; 217 struct in_addr sc_dst; 218 tcp_seq sc_irs; 219 tcp_seq sc_iss; 220 int sc_flags; 221 222 #define SCF_SYNACK_REXMT 0x0001 /* SYN,ACK was retransmitted */ 223 #define SCF_TIMESTAMP 0x0002 /* peer will do timestamps */ 224 225 struct mbuf *sc_ipopts; /* IP options */ 226 u_int16_t sc_sport; 227 u_int16_t sc_dport; 228 u_int16_t sc_peermaxseg; 229 u_int16_t sc_ourmaxseg; 230 u_int8_t sc_timer; 231 u_int8_t sc_request_r_scale : 4, 232 sc_requested_s_scale : 4; 233 }; 234 235 struct syn_cache_head { 236 struct syn_cache *sch_first; /* First entry in the bucket */ 237 struct syn_cache *sch_last; /* Last entry in the bucket */ 238 struct syn_cache_head *sch_headq; /* The next non-empty bucket */ 239 int16_t sch_timer_sum; /* Total time in this bucket */ 240 u_int16_t sch_length; /* @ # elements in bucket */ 241 }; 242 243 #define intotcpcb(ip) ((struct tcpcb *)(ip)->inp_ppcb) 244 #define sototcpcb(so) (intotcpcb(sotoinpcb(so))) 245 246 /* 247 * The smoothed round-trip time and estimated variance 248 * are stored as fixed point numbers scaled by the values below. 249 * For convenience, these scales are also used in smoothing the average 250 * (smoothed = (1/scale)sample + ((scale-1)/scale)smoothed). 251 * With these scales, srtt has 3 bits to the right of the binary point, 252 * and thus an "ALPHA" of 0.875. rttvar has 2 bits to the right of the 253 * binary point, and is smoothed with an ALPHA of 0.75. 254 */ 255 #define TCP_RTT_SHIFT 3 /* shift for srtt; 3 bits frac. */ 256 #define TCP_RTTVAR_SHIFT 2 /* multiplier for rttvar; 2 bits */ 257 258 /* 259 * The initial retransmission should happen at rtt + 4 * rttvar. 260 * Because of the way we do the smoothing, srtt and rttvar 261 * will each average +1/2 tick of bias. When we compute 262 * the retransmit timer, we want 1/2 tick of rounding and 263 * 1 extra tick because of +-1/2 tick uncertainty in the 264 * firing of the timer. The bias will give us exactly the 265 * 1.5 tick we need. But, because the bias is 266 * statistical, we have to test that we don't drop below 267 * the minimum feasible timer (which is 2 ticks). 268 * This macro assumes that the value of 1<<TCP_RTTVAR_SHIFT 269 * is the same as the multiplier for rttvar. 270 */ 271 #define TCP_REXMTVAL(tp) \ 272 ((((tp)->t_srtt >> TCP_RTT_SHIFT) + (tp)->t_rttvar) >> 2) 273 274 #ifdef _KERNEL 275 /* 276 * Compute the initial window for slow start. 277 */ 278 extern int tcp_init_win; 279 #define TCP_INITIAL_WINDOW(iw, segsz) \ 280 (((iw) == 0) ? (min(4 * (segsz), max(2 * (segsz), 4380))) : \ 281 ((segsz) * (iw))) 282 #endif /* _KERNEL */ 283 284 /* 285 * TCP statistics. 286 * Many of these should be kept per connection, 287 * but that's inconvenient at the moment. 288 */ 289 struct tcpstat { 290 u_long tcps_connattempt; /* connections initiated */ 291 u_long tcps_accepts; /* connections accepted */ 292 u_long tcps_connects; /* connections established */ 293 u_long tcps_drops; /* connections dropped */ 294 u_long tcps_conndrops; /* embryonic connections dropped */ 295 u_long tcps_closed; /* conn. closed (includes drops) */ 296 u_long tcps_segstimed; /* segs where we tried to get rtt */ 297 u_long tcps_rttupdated; /* times we succeeded */ 298 u_long tcps_delack; /* delayed acks sent */ 299 u_long tcps_timeoutdrop; /* conn. dropped in rxmt timeout */ 300 u_long tcps_rexmttimeo; /* retransmit timeouts */ 301 u_long tcps_persisttimeo; /* persist timeouts */ 302 u_long tcps_keeptimeo; /* keepalive timeouts */ 303 u_long tcps_keepprobe; /* keepalive probes sent */ 304 u_long tcps_keepdrops; /* connections dropped in keepalive */ 305 u_long tcps_persistdrops; /* connections dropped in persist */ 306 u_long tcps_connsdrained; /* connections drained due to memory 307 shortage */ 308 309 u_long tcps_sndtotal; /* total packets sent */ 310 u_long tcps_sndpack; /* data packets sent */ 311 u_long tcps_sndbyte; /* data bytes sent */ 312 u_long tcps_sndrexmitpack; /* data packets retransmitted */ 313 u_long tcps_sndrexmitbyte; /* data bytes retransmitted */ 314 u_long tcps_sndacks; /* ack-only packets sent */ 315 u_long tcps_sndprobe; /* window probes sent */ 316 u_long tcps_sndurg; /* packets sent with URG only */ 317 u_long tcps_sndwinup; /* window update-only packets sent */ 318 u_long tcps_sndctrl; /* control (SYN|FIN|RST) packets sent */ 319 320 u_long tcps_rcvtotal; /* total packets received */ 321 u_long tcps_rcvpack; /* packets received in sequence */ 322 u_long tcps_rcvbyte; /* bytes received in sequence */ 323 u_long tcps_rcvbadsum; /* packets received with ccksum errs */ 324 u_long tcps_rcvbadoff; /* packets received with bad offset */ 325 u_long tcps_rcvmemdrop; /* packets dropped for lack of memory */ 326 u_long tcps_rcvshort; /* packets received too short */ 327 u_long tcps_rcvduppack; /* duplicate-only packets received */ 328 u_long tcps_rcvdupbyte; /* duplicate-only bytes received */ 329 u_long tcps_rcvpartduppack; /* packets with some duplicate data */ 330 u_long tcps_rcvpartdupbyte; /* dup. bytes in part-dup. packets */ 331 u_long tcps_rcvoopack; /* out-of-order packets received */ 332 u_long tcps_rcvoobyte; /* out-of-order bytes received */ 333 u_long tcps_rcvpackafterwin; /* packets with data after window */ 334 u_long tcps_rcvbyteafterwin; /* bytes rcvd after window */ 335 u_long tcps_rcvafterclose; /* packets rcvd after "close" */ 336 u_long tcps_rcvwinprobe; /* rcvd window probe packets */ 337 u_long tcps_rcvdupack; /* rcvd duplicate acks */ 338 u_long tcps_rcvacktoomuch; /* rcvd acks for unsent data */ 339 u_long tcps_rcvackpack; /* rcvd ack packets */ 340 u_long tcps_rcvackbyte; /* bytes acked by rcvd acks */ 341 u_long tcps_rcvwinupd; /* rcvd window update packets */ 342 u_long tcps_pawsdrop; /* segments dropped due to PAWS */ 343 u_long tcps_predack; /* times hdr predict ok for acks */ 344 u_long tcps_preddat; /* times hdr predict ok for data pkts */ 345 346 u_long tcps_pcbhashmiss; /* input packets missing pcb hash */ 347 u_long tcps_noport; /* no socket on port */ 348 u_long tcps_badsyn; /* received ack for which we have 349 no SYN in compressed state */ 350 351 /* These statistics deal with the SYN cache. */ 352 u_long tcps_sc_added; /* # of entries added */ 353 u_long tcps_sc_completed; /* # of connections completed */ 354 u_long tcps_sc_timed_out; /* # of entries timed out */ 355 u_long tcps_sc_overflowed; /* # dropped due to overflow */ 356 u_long tcps_sc_reset; /* # dropped due to RST */ 357 u_long tcps_sc_unreach; /* # dropped due to ICMP unreach */ 358 u_long tcps_sc_bucketoverflow; /* # dropped due to bucket overflow */ 359 u_long tcps_sc_aborted; /* # of entries aborted (no mem) */ 360 u_long tcps_sc_dupesyn; /* # of duplicate SYNs received */ 361 u_long tcps_sc_dropped; /* # of SYNs dropped (no route/mem) */ 362 u_long tcps_sc_collisions; /* # of hash collisions */ 363 }; 364 365 /* 366 * Names for TCP sysctl objects. 367 */ 368 #define TCPCTL_RFC1323 1 /* RFC1323 timestamps/scaling */ 369 #define TCPCTL_SENDSPACE 2 /* default send buffer */ 370 #define TCPCTL_RECVSPACE 3 /* default recv buffer */ 371 #define TCPCTL_MSSDFLT 4 /* default seg size */ 372 #define TCPCTL_SYN_CACHE_LIMIT 5 /* max size of comp. state engine */ 373 #define TCPCTL_SYN_BUCKET_LIMIT 6 /* max size of hash bucket */ 374 #define TCPCTL_SYN_CACHE_INTER 7 /* interval of comp. state timer */ 375 #define TCPCTL_INIT_WIN 8 /* initial window */ 376 #define TCPCTL_MSS_IFMTU 9 /* mss from interface, not in_maxmtu */ 377 #define TCPCTL_MAXID 10 378 379 #define TCPCTL_NAMES { \ 380 { 0, 0 }, \ 381 { "rfc1323", CTLTYPE_INT }, \ 382 { "sendspace", CTLTYPE_INT }, \ 383 { "recvspace", CTLTYPE_INT }, \ 384 { "mssdflt", CTLTYPE_INT }, \ 385 { "syn_cache_limit", CTLTYPE_INT }, \ 386 { "syn_bucket_limit", CTLTYPE_INT }, \ 387 { "syn_cache_interval", CTLTYPE_INT },\ 388 { "init_win", CTLTYPE_INT }, \ 389 { "mss_ifmtu", CTLTYPE_INT }, \ 390 } 391 392 #ifdef _KERNEL 393 struct inpcbtable tcbtable; /* head of queue of active tcpcb's */ 394 struct tcpstat tcpstat; /* tcp statistics */ 395 u_int32_t tcp_now; /* for RFC 1323 timestamps */ 396 extern int tcp_do_rfc1323; /* enabled/disabled? */ 397 extern int tcp_mssdflt; /* default seg size */ 398 extern int tcp_init_win; /* initial window */ 399 extern int tcp_mss_ifmtu; /* take MSS from interface, not in_maxmtu */ 400 extern int tcp_syn_cache_limit; /* max entries for compressed state engine */ 401 extern int tcp_syn_bucket_limit;/* max entries per hash bucket */ 402 extern int tcp_syn_cache_interval; /* compressed state timer */ 403 404 extern int tcp_syn_cache_size; 405 extern int tcp_syn_cache_timeo; 406 extern struct syn_cache_head tcp_syn_cache[], *tcp_syn_cache_first; 407 extern u_long syn_cache_count; 408 409 int tcp_attach __P((struct socket *)); 410 void tcp_canceltimers __P((struct tcpcb *)); 411 struct tcpcb * 412 tcp_close __P((struct tcpcb *)); 413 void *tcp_ctlinput __P((int, struct sockaddr *, void *)); 414 int tcp_ctloutput __P((int, struct socket *, int, int, struct mbuf **)); 415 struct tcpcb * 416 tcp_disconnect __P((struct tcpcb *)); 417 struct tcpcb * 418 tcp_drop __P((struct tcpcb *, int)); 419 void tcp_dooptions __P((struct tcpcb *, 420 u_char *, int, struct tcpiphdr *, struct tcp_opt_info *)); 421 void tcp_drain __P((void)); 422 void tcp_established __P((struct tcpcb *)); 423 void tcp_fasttimo __P((void)); 424 void tcp_init __P((void)); 425 void tcp_input __P((struct mbuf *, ...)); 426 u_long tcp_mss_to_advertise __P((const struct ifnet *)); 427 void tcp_mss_from_peer __P((struct tcpcb *, int)); 428 void tcp_mtudisc __P((struct inpcb *, int)); 429 struct tcpcb * 430 tcp_newtcpcb __P((struct inpcb *)); 431 void tcp_notify __P((struct inpcb *, int)); 432 u_int tcp_optlen __P((struct tcpcb *)); 433 int tcp_output __P((struct tcpcb *)); 434 void tcp_pulloutofband __P((struct socket *, 435 struct tcpiphdr *, struct mbuf *)); 436 void tcp_quench __P((struct inpcb *, int)); 437 int tcp_reass __P((struct tcpcb *, struct tcpiphdr *, struct mbuf *)); 438 int tcp_respond __P((struct tcpcb *, 439 struct tcpiphdr *, struct mbuf *, tcp_seq, tcp_seq, int)); 440 void tcp_rmx_rtt __P((struct tcpcb *)); 441 void tcp_setpersist __P((struct tcpcb *)); 442 void tcp_slowtimo __P((void)); 443 struct tcpiphdr * 444 tcp_template __P((struct tcpcb *)); 445 struct tcpcb * 446 tcp_timers __P((struct tcpcb *, int)); 447 void tcp_trace __P((int, int, struct tcpcb *, struct tcpiphdr *, int)); 448 struct tcpcb * 449 tcp_usrclosed __P((struct tcpcb *)); 450 int tcp_sysctl __P((int *, u_int, void *, size_t *, void *, size_t)); 451 int tcp_usrreq __P((struct socket *, 452 int, struct mbuf *, struct mbuf *, struct mbuf *, struct proc *)); 453 void tcp_xmit_timer __P((struct tcpcb *, int)); 454 tcp_seq tcp_new_iss __P((void *, u_long, tcp_seq)); 455 456 int syn_cache_add __P((struct socket *, struct mbuf *, u_char *, 457 int, struct tcp_opt_info *)); 458 void syn_cache_unreach __P((struct ip *, struct tcphdr *)); 459 struct socket * 460 syn_cache_get __P((struct socket *so, struct mbuf *)); 461 void syn_cache_insert __P((struct syn_cache *, struct syn_cache ***, 462 struct syn_cache_head **)); 463 struct syn_cache * 464 syn_cache_lookup __P((struct tcpiphdr *, struct syn_cache ***, 465 struct syn_cache_head **)); 466 void syn_cache_reset __P((struct tcpiphdr *)); 467 int syn_cache_respond __P((struct syn_cache *, struct mbuf *, 468 register struct tcpiphdr *, long, u_long)); 469 void syn_cache_timer __P((int)); 470 471 #endif 472 473 #endif /* _NETINET_TCP_VAR_H_ */ 474