2 * Copyright (c) 2003-2004 Jeffrey Hsu. All rights reserved.
3 * Copyright (c) 1982, 1986, 1993, 1994, 1995
4 * The Regents of the University of California. All rights reserved.
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7 * modification, are permitted provided that the following conditions
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16 * This product includes software developed by the University of
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34 * @(#)tcp_var.h 8.4 (Berkeley) 5/24/95
35 * $FreeBSD: src/sys/netinet/tcp_var.h,v 1.56.2.13 2003/02/03 02:34:07 hsu Exp $
36 * $DragonFly: src/sys/netinet/tcp_var.h,v 1.19 2004/04/29 10:06:41 hmp Exp $
39 #ifndef _NETINET_TCP_VAR_H_
40 #define _NETINET_TCP_VAR_H_
42 #include <netinet/in_pcb.h> /* needed for in_conninfo, inp_gen_t */
45 * Kernel variables for tcp.
47 extern int tcp_do_rfc1323;
48 extern int tcp_do_rfc1644;
50 /* TCP segment queue entry */
52 LIST_ENTRY(tseg_qent) tqe_q;
53 int tqe_len; /* TCP segment data length */
54 struct tcphdr *tqe_th; /* a pointer to tcp header */
55 struct mbuf *tqe_m; /* mbuf contains packet */
57 LIST_HEAD(tsegqe_head, tseg_qent);
58 extern int tcp_reass_maxseg;
59 extern int tcp_reass_qsize;
61 MALLOC_DECLARE(M_TSEGQ);
65 u_char tt_ipgen[40]; /* the size must be of max ip header, now IPv6 */
69 #define tcp6cb tcpcb /* for KAME src sync over BSD*'s */
72 * Tcp control block, one per tcp; fields:
73 * Organized for 16 byte cacheline efficiency.
76 struct tsegqe_head t_segq;
77 int t_dupacks; /* consecutive dup acks recd */
78 struct tcptemp *unused; /* unused */
80 struct callout *tt_rexmt; /* retransmit timer */
81 struct callout *tt_persist; /* retransmit persistence */
82 struct callout *tt_keep; /* keepalive */
83 struct callout *tt_2msl; /* 2*msl TIME_WAIT timer */
84 struct callout *tt_delack; /* delayed ACK timer */
86 struct inpcb *t_inpcb; /* back pointer to internet pcb */
87 int t_state; /* state of this connection */
89 #define TF_ACKNOW 0x00000001 /* ack peer immediately */
90 #define TF_DELACK 0x00000002 /* ack, but try to delay it */
91 #define TF_NODELAY 0x00000004 /* don't delay packets to coalesce */
92 #define TF_NOOPT 0x00000008 /* don't use tcp options */
93 #define TF_SENTFIN 0x00000010 /* have sent FIN */
94 #define TF_REQ_SCALE 0x00000020 /* have/will request window scaling */
95 #define TF_RCVD_SCALE 0x00000040 /* other side has requested scaling */
96 #define TF_REQ_TSTMP 0x00000080 /* have/will request timestamps */
97 #define TF_RCVD_TSTMP 0x00000100 /* a timestamp was received in SYN */
98 #define TF_SACK_PERMIT 0x00000200 /* other side said I could SACK */
99 #define TF_NEEDSYN 0x00000400 /* send SYN (implicit state) */
100 #define TF_NEEDFIN 0x00000800 /* send FIN (implicit state) */
101 #define TF_NOPUSH 0x00001000 /* don't push */
102 #define TF_REQ_CC 0x00002000 /* have/will request CC */
103 #define TF_RCVD_CC 0x00004000 /* a CC was received in SYN */
104 #define TF_SENDCCNEW 0x00008000 /* send CCnew instead of CC in SYN */
105 #define TF_MORETOCOME 0x00010000 /* More data to be appended to sock */
106 #define TF_LQ_OVERFLOW 0x00020000 /* listen queue overflow */
107 #define TF_LASTIDLE 0x00040000 /* connection was previously idle */
108 #define TF_RXWIN0SENT 0x00080000 /* sent a receiver win 0 in response */
109 #define TF_FASTRECOVERY 0x00100000 /* in NewReno Fast Recovery */
110 #define TF_WASFRECOVERY 0x00200000 /* was in NewReno Fast Recovery */
111 #define TF_FIRSTACCACK 0x00400000 /* Look for 1st acceptable ACK. */
112 #define TF_FASTREXMT 0x00800000 /* Did Fast Retransmit. */
113 #define TF_EARLYREXMT 0x01000000 /* Did Early (Fast) Retransmit. */
114 int t_force; /* 1 if forcing out a byte */
116 tcp_seq snd_una; /* send unacknowledged */
117 tcp_seq snd_max; /* highest sequence number sent;
118 * used to recognize retransmits
120 tcp_seq snd_nxt; /* send next */
121 tcp_seq snd_up; /* send urgent pointer */
123 tcp_seq snd_wl1; /* window update seg seq number */
124 tcp_seq snd_wl2; /* window update seg ack number */
125 tcp_seq iss; /* initial send sequence number */
126 tcp_seq irs; /* initial receive sequence number */
128 tcp_seq rcv_nxt; /* receive next */
129 tcp_seq rcv_adv; /* advertised window */
130 u_long rcv_wnd; /* receive window */
131 tcp_seq rcv_up; /* receive urgent pointer */
133 u_long snd_wnd; /* send window */
134 u_long snd_cwnd; /* congestion-controlled window */
135 u_long snd_bwnd; /* bandwidth-controlled window */
136 u_long snd_ssthresh; /* snd_cwnd size threshold for
137 * for slow start exponential to
140 u_long snd_bandwidth; /* calculated bandwidth or 0 */
141 tcp_seq snd_recover; /* for use in NewReno fast recovery */
143 u_int t_maxopd; /* mss plus options */
145 u_long t_rcvtime; /* inactivity time */
146 u_long t_starttime; /* time connection was established */
147 int t_rtttime; /* round trip time */
148 tcp_seq t_rtseq; /* sequence number being timed */
150 int t_bw_rtttime; /* used for bandwidth calculation */
151 tcp_seq t_bw_rtseq; /* used for bandwidth calculation */
153 int t_rxtcur; /* current retransmit value (ticks) */
154 u_int t_maxseg; /* maximum segment size */
155 int t_srtt; /* smoothed round-trip time */
156 int t_rttvar; /* variance in round-trip time */
158 int t_rxtshift; /* log(2) of rexmt exp. backoff */
159 u_int t_rttmin; /* minimum rtt allowed */
160 u_int t_rttbest; /* best rtt we've seen */
161 u_long t_rttupdated; /* number of times rtt sampled */
162 u_long max_sndwnd; /* largest window peer has offered */
164 int t_softerror; /* possible error not yet reported */
165 /* out-of-band data */
166 char t_oobflags; /* have some */
167 char t_iobc; /* input character */
168 #define TCPOOB_HAVEDATA 0x01
169 #define TCPOOB_HADDATA 0x02
170 /* RFC 1323 variables */
171 u_char snd_scale; /* window scaling for send window */
172 u_char rcv_scale; /* window scaling for recv window */
173 u_char request_r_scale; /* pending window scaling */
174 u_char requested_s_scale;
175 u_long ts_recent; /* timestamp echo data */
177 u_long ts_recent_age; /* when last updated */
178 tcp_seq last_ack_sent;
179 /* RFC 1644 variables */
180 tcp_cc cc_send; /* send connection count */
181 tcp_cc cc_recv; /* receive connection count */
183 u_long snd_cwnd_prev; /* cwnd prior to retransmit */
184 u_long snd_ssthresh_prev; /* ssthresh prior to retransmit */
185 tcp_seq snd_recover_prev; /* snd_recover prior to retransmit */
186 u_long t_badrxtwin; /* window for retransmit recovery */
187 u_long t_rexmtTS; /* timestamp of last retransmit */
188 u_char snd_limited; /* segments limited transmitted */
191 #define IN_FASTRECOVERY(tp) (tp->t_flags & TF_FASTRECOVERY)
192 #define ENTER_FASTRECOVERY(tp) tp->t_flags |= TF_FASTRECOVERY
193 #define EXIT_FASTRECOVERY(tp) tp->t_flags &= ~TF_FASTRECOVERY
199 #define tcpstat tcpstats_ary[_GD->gd_cpuid]
201 #define tcpstat tcpstats_ary[0]
205 extern struct tcp_stats tcpstats_ary[MAXCPU];
212 u_long tcps_connattempt; /* connections initiated */
213 u_long tcps_accepts; /* connections accepted */
214 u_long tcps_connects; /* connections established */
215 u_long tcps_drops; /* connections dropped */
216 u_long tcps_conndrops; /* embryonic connections dropped */
217 u_long tcps_closed; /* conn. closed (includes drops) */
218 u_long tcps_segstimed; /* segs where we tried to get rtt */
219 u_long tcps_rttupdated; /* times we succeeded */
220 u_long tcps_delack; /* delayed acks sent */
221 u_long tcps_timeoutdrop; /* conn. dropped in rxmt timeout */
222 u_long tcps_rexmttimeo; /* retransmit timeouts */
223 u_long tcps_persisttimeo; /* persist timeouts */
224 u_long tcps_keeptimeo; /* keepalive timeouts */
225 u_long tcps_keepprobe; /* keepalive probes sent */
226 u_long tcps_keepdrops; /* connections dropped in keepalive */
228 u_long tcps_sndtotal; /* total packets sent */
229 u_long tcps_sndpack; /* data packets sent */
230 u_long tcps_sndbyte; /* data bytes sent */
231 u_long tcps_sndrexmitpack; /* data packets retransmitted */
232 u_long tcps_sndrexmitbyte; /* data bytes retransmitted */
233 u_long tcps_sndfastrexmit; /* Fast Retransmissions */
234 u_long tcps_sndearlyrexmit; /* early Fast Retransmissions */
235 u_long tcps_sndlimited; /* Limited Transmit packets */
236 u_long tcps_sndrtobad; /* spurious RTO retransmissions */
237 u_long tcps_sndfastrexmitbad; /* spurious Fast Retransmissions */
238 u_long tcps_sndearlyrexmitbad; /* spurious early Fast Retransmissions,
239 a subset of tcps_sndfastrexmitbad */
240 u_long tcps_eifeldetected; /* Eifel-detected spurious rexmits */
241 u_long tcps_rttcantdetect; /* Eifel but not 1/2 RTT-detectable */
242 u_long tcps_rttdetected; /* RTT-detected spurious RTO rexmits */
243 u_long tcps_sndacks; /* ack-only packets sent */
244 u_long tcps_sndprobe; /* window probes sent */
245 u_long tcps_sndurg; /* packets sent with URG only */
246 u_long tcps_sndwinup; /* window update-only packets sent */
247 u_long tcps_sndctrl; /* control (SYN|FIN|RST) packets sent */
249 u_long tcps_rcvtotal; /* total packets received */
250 u_long tcps_rcvpack; /* packets received in sequence */
251 u_long tcps_rcvbyte; /* bytes received in sequence */
252 u_long tcps_rcvbadsum; /* packets received with ccksum errs */
253 u_long tcps_rcvbadoff; /* packets received with bad offset */
254 u_long tcps_rcvmemdrop; /* packets dropped for lack of memory */
255 u_long tcps_rcvshort; /* packets received too short */
256 u_long tcps_rcvduppack; /* duplicate-only packets received */
257 u_long tcps_rcvdupbyte; /* duplicate-only bytes received */
258 u_long tcps_rcvpartduppack; /* packets with some duplicate data */
259 u_long tcps_rcvpartdupbyte; /* dup. bytes in part-dup. packets */
260 u_long tcps_rcvoopack; /* out-of-order packets received */
261 u_long tcps_rcvoobyte; /* out-of-order bytes received */
262 u_long tcps_rcvpackafterwin; /* packets with data after window */
263 u_long tcps_rcvbyteafterwin; /* bytes rcvd after window */
264 u_long tcps_rcvafterclose; /* packets rcvd after "close" */
265 u_long tcps_rcvwinprobe; /* rcvd window probe packets */
266 u_long tcps_rcvdupack; /* rcvd duplicate acks */
267 u_long tcps_rcvacktoomuch; /* rcvd acks for unsent data */
268 u_long tcps_rcvackpack; /* rcvd ack packets */
269 u_long tcps_rcvackbyte; /* bytes acked by rcvd acks */
270 u_long tcps_rcvwinupd; /* rcvd window update packets */
271 u_long tcps_pawsdrop; /* segments dropped due to PAWS */
272 u_long tcps_predack; /* times hdr predict ok for acks */
273 u_long tcps_preddat; /* times hdr predict ok for data pkts */
274 u_long tcps_pcbcachemiss;
275 u_long tcps_cachedrtt; /* times cached RTT in route updated */
276 u_long tcps_cachedrttvar; /* times cached rttvar updated */
277 u_long tcps_cachedssthresh; /* times cached ssthresh updated */
278 u_long tcps_usedrtt; /* times RTT initialized from route */
279 u_long tcps_usedrttvar; /* times RTTVAR initialized from rt */
280 u_long tcps_usedssthresh; /* times ssthresh initialized from rt*/
281 u_long tcps_persistdrop; /* timeout in persist state */
282 u_long tcps_badsyn; /* bogus SYN, e.g. premature ACK */
283 u_long tcps_mturesent; /* resends due to MTU discovery */
284 u_long tcps_listendrop; /* listen queue overflows */
286 u_long tcps_sc_added; /* entry added to syncache */
287 u_long tcps_sc_retransmitted; /* syncache entry was retransmitted */
288 u_long tcps_sc_dupsyn; /* duplicate SYN packet */
289 u_long tcps_sc_dropped; /* could not reply to packet */
290 u_long tcps_sc_completed; /* successful extraction of entry */
291 u_long tcps_sc_bucketoverflow; /* syncache per-bucket limit hit */
292 u_long tcps_sc_cacheoverflow; /* syncache cache limit hit */
293 u_long tcps_sc_reset; /* RST removed entry from syncache */
294 u_long tcps_sc_stale; /* timed out or listen socket gone */
295 u_long tcps_sc_aborted; /* syncache entry aborted */
296 u_long tcps_sc_badack; /* removed due to bad ACK */
297 u_long tcps_sc_unreach; /* ICMP unreachable received */
298 u_long tcps_sc_zonefail; /* zalloc() failed */
299 u_long tcps_sc_sendcookie; /* SYN cookie sent */
300 u_long tcps_sc_recvcookie; /* SYN cookie received */
304 * Structure to hold TCP options that are only used during segment
305 * processing (in tcp_input), but not held in the tcpcb.
306 * It's basically used to reduce the number of parameters
310 u_long to_flags; /* which options are present */
311 #define TOF_TS 0x0001 /* timestamp */
312 #define TOF_CC 0x0002 /* CC and CCnew are exclusive */
313 #define TOF_CCNEW 0x0004
314 #define TOF_CCECHO 0x0008
315 #define TOF_MSS 0x0010
316 #define TOF_SCALE 0x0020
319 tcp_cc to_cc; /* holds CC or CCnew */
322 u_int8_t to_requested_s_scale;
327 inp_gen_t sc_inp_gencnt; /* pointer check */
328 struct tcpcb *sc_tp; /* tcb for listening socket */
329 struct mbuf *sc_ipopts; /* source route */
330 struct in_conninfo sc_inc; /* addresses */
331 #define sc_route sc_inc.inc_route
332 #define sc_route6 sc_inc.inc6_route
333 u_int32_t sc_tsrecent;
334 tcp_cc sc_cc_send; /* holds CC or CCnew */
336 tcp_seq sc_irs; /* seq from peer */
337 tcp_seq sc_iss; /* our ISS */
338 u_long sc_rxttime; /* retransmit time */
339 u_int16_t sc_rxtslot; /* retransmit counter */
340 u_int16_t sc_peer_mss; /* peer's MSS */
341 u_int16_t sc_wnd; /* advertised window */
342 u_int8_t sc_requested_s_scale:4,
343 sc_request_r_scale:4;
345 #define SCF_NOOPT 0x01 /* no TCP options */
346 #define SCF_WINSCALE 0x02 /* negotiated window scaling */
347 #define SCF_TIMESTAMP 0x04 /* negotiated timestamps */
348 #define SCF_CC 0x08 /* negotiated CC */
349 #define SCF_UNREACH 0x10 /* icmp unreachable received */
350 #define SCF_KEEPROUTE 0x20 /* keep cloned route */
351 TAILQ_ENTRY(syncache) sc_hash;
352 TAILQ_ENTRY(syncache) sc_timerq;
355 struct syncache_head {
356 TAILQ_HEAD(, syncache) sch_bucket;
361 * The TAO cache entry which is stored in the protocol family specific
362 * portion of the route metrics.
365 tcp_cc tao_cc; /* latest CC in valid SYN */
366 tcp_cc tao_ccsent; /* latest CC sent to peer */
367 u_short tao_mssopt; /* peer's cached MSS */
369 u_short tao_flags; /* cache status flags */
370 #define TAOF_DONT 0x0001 /* peer doesn't understand rfc1644 */
371 #define TAOF_OK 0x0002 /* peer does understand rfc1644 */
372 #define TAOF_UNDEF 0 /* we don't know yet */
375 #define rmx_taop(r) ((struct rmxp_tao *)(r).rmx_filler)
377 #define intotcpcb(ip) ((struct tcpcb *)(ip)->inp_ppcb)
378 #define sototcpcb(so) (intotcpcb(sotoinpcb(so)))
381 * The smoothed round-trip time and estimated variance
382 * are stored as fixed point numbers scaled by the values below.
383 * For convenience, these scales are also used in smoothing the average
384 * (smoothed = (1/scale)sample + ((scale-1)/scale)smoothed).
385 * With these scales, srtt has 3 bits to the right of the binary point,
386 * and thus an "ALPHA" of 0.875. rttvar has 2 bits to the right of the
387 * binary point, and is smoothed with an ALPHA of 0.75.
389 #define TCP_RTT_SCALE 32 /* multiplier for srtt; 3 bits frac. */
390 #define TCP_RTT_SHIFT 5 /* shift for srtt; 3 bits frac. */
391 #define TCP_RTTVAR_SCALE 16 /* multiplier for rttvar; 2 bits */
392 #define TCP_RTTVAR_SHIFT 4 /* shift for rttvar; 2 bits */
393 #define TCP_DELTA_SHIFT 2 /* see tcp_input.c */
396 * The initial retransmission should happen at rtt + 4 * rttvar.
397 * Because of the way we do the smoothing, srtt and rttvar
398 * will each average +1/2 tick of bias. When we compute
399 * the retransmit timer, we want 1/2 tick of rounding and
400 * 1 extra tick because of +-1/2 tick uncertainty in the
401 * firing of the timer. The bias will give us exactly the
402 * 1.5 tick we need. But, because the bias is
403 * statistical, we have to test that we don't drop below
404 * the minimum feasible timer (which is 2 ticks).
405 * This version of the macro adapted from a paper by Lawrence
406 * Brakmo and Larry Peterson which outlines a problem caused
407 * by insufficient precision in the original implementation,
408 * which results in inappropriately large RTO values for very
411 #define TCP_REXMTVAL(tp) \
412 max((tp)->t_rttmin, (((tp)->t_srtt >> (TCP_RTT_SHIFT - TCP_DELTA_SHIFT)) \
413 + (tp)->t_rttvar) >> TCP_DELTA_SHIFT)
416 * TCB structure exported to user-land via sysctl(3).
417 * Evil hack: declare only if in_pcb.h and sys/socketvar.h have been
418 * included. Not all of our clients do.
420 #if defined(_NETINET_IN_PCB_H_) && defined(_SYS_SOCKETVAR_H_)
425 struct xsocket xt_socket;
426 u_quad_t xt_alignment_hack;
431 * Names for TCP sysctl objects
433 #define TCPCTL_DO_RFC1323 1 /* use RFC-1323 extensions */
434 #define TCPCTL_DO_RFC1644 2 /* use RFC-1644 extensions */
435 #define TCPCTL_MSSDFLT 3 /* MSS default */
436 #define TCPCTL_STATS 4 /* statistics (read-only) */
437 #define TCPCTL_RTTDFLT 5 /* default RTT estimate */
438 #define TCPCTL_KEEPIDLE 6 /* keepalive idle timer */
439 #define TCPCTL_KEEPINTVL 7 /* interval to send keepalives */
440 #define TCPCTL_SENDSPACE 8 /* send buffer space */
441 #define TCPCTL_RECVSPACE 9 /* receive buffer space */
442 #define TCPCTL_KEEPINIT 10 /* timeout for establishing syn */
443 #define TCPCTL_PCBLIST 11 /* list of all outstanding PCBs */
444 #define TCPCTL_DELACKTIME 12 /* time before sending delayed ACK */
445 #define TCPCTL_V6MSSDFLT 13 /* MSS default for IPv6 */
446 #define TCPCTL_MAXID 14
448 #define TCPCTL_NAMES { \
450 { "rfc1323", CTLTYPE_INT }, \
451 { "rfc1644", CTLTYPE_INT }, \
452 { "mssdflt", CTLTYPE_INT }, \
453 { "stats", CTLTYPE_STRUCT }, \
454 { "rttdflt", CTLTYPE_INT }, \
455 { "keepidle", CTLTYPE_INT }, \
456 { "keepintvl", CTLTYPE_INT }, \
457 { "sendspace", CTLTYPE_INT }, \
458 { "recvspace", CTLTYPE_INT }, \
459 { "keepinit", CTLTYPE_INT }, \
460 { "pcblist", CTLTYPE_STRUCT }, \
461 { "delacktime", CTLTYPE_INT }, \
462 { "v6mssdflt", CTLTYPE_INT }, \
467 SYSCTL_DECL(_net_inet_tcp);
470 extern struct inpcbinfo tcbinfo[];
471 extern int tcp_mssdflt; /* XXX */
472 extern int tcp_delack_enabled;
473 extern int tcp_do_newreno;
474 extern int path_mtu_discovery;
476 extern int ss_fltsz_local;
478 int tcp_addrcpu(in_addr_t faddr, in_port_t fport,
479 in_addr_t laddr, in_port_t lport);
481 tcp_addrport(in_addr_t faddr, in_port_t fport,
482 in_addr_t laddr, in_port_t lport);
483 void tcp_canceltimers (struct tcpcb *);
485 tcp_close (struct tcpcb *);
486 void tcp_ctlinput (int, struct sockaddr *, void *);
487 int tcp_ctloutput (struct socket *, struct sockopt *);
491 tcp_drop (struct tcpcb *, int);
492 void tcp_drain (void);
493 void tcp_fasttimo (void);
495 tcp_gettaocache (struct in_conninfo *);
496 void tcp_init (void);
497 void tcp_thread_init (void);
498 void tcp_input (struct mbuf *, int, int);
499 void tcp_mss (struct tcpcb *, int);
500 int tcp_mssopt (struct tcpcb *);
501 void tcp_drop_syn_sent (struct inpcb *, int);
502 void tcp_mtudisc (struct inpcb *, int);
504 tcp_newtcpcb (struct inpcb *);
505 int tcp_output (struct tcpcb *);
506 void tcp_quench (struct inpcb *, int);
507 void tcp_respond (struct tcpcb *, void *,
508 struct tcphdr *, struct mbuf *, tcp_seq, tcp_seq, int);
510 tcp_rtlookup (struct in_conninfo *);
511 void tcp_save_congestion_state(struct tcpcb *tp);
512 void tcp_revert_congestion_state(struct tcpcb *tp);
513 void tcp_setpersist (struct tcpcb *);
514 void tcp_slowtimo (void);
516 tcp_maketemplate (struct tcpcb *);
517 void tcp_fillheaders (struct tcpcb *, void *, void *);
519 tcp_soport(struct socket *, struct sockaddr *nam, int req);
521 tcp_timers (struct tcpcb *, int);
522 void tcp_trace (int, int, struct tcpcb *, void *, struct tcphdr *,
524 void tcp_xmit_bandwidth_limit(struct tcpcb *tp, tcp_seq ack_seq);
525 void syncache_init(void);
526 void syncache_unreach(struct in_conninfo *, struct tcphdr *);
527 int syncache_expand(struct in_conninfo *, struct tcphdr *,
528 struct socket **, struct mbuf *);
529 int syncache_add(struct in_conninfo *, struct tcpopt *,
530 struct tcphdr *, struct socket **, struct mbuf *);
531 void syncache_chkrst(struct in_conninfo *, struct tcphdr *);
532 void syncache_badack(struct in_conninfo *);
534 extern struct pr_usrreqs tcp_usrreqs;
535 extern u_long tcp_sendspace;
536 extern u_long tcp_recvspace;
537 tcp_seq tcp_new_isn (struct tcpcb *);
541 #endif /* _NETINET_TCP_VAR_H_ */