4ed600dbd0
- Don't overload t_maxseg. Previous behavior was to set it to the min of the peer's advertised MSS, our advertised MSS, and tcp_mssdflt (for non-local networks). This breaks PMTU discovery running on either host. Instead, remember the MSS we advertise, and use it as appropriate (in silly window avoidance). - Per last bullet, split tcp_mss() into several functions for handling MSS (ours and peer's), and performing various tasks when a connection becomes ESTABLISHED. - Introduce a new function, tcp_segsize(), which computes the max size for every segment transmitted in tcp_output(). This will eventually be used to hook in PMTU discovery.
384 lines
16 KiB
C
384 lines
16 KiB
C
/* $NetBSD: tcp_var.h,v 1.23 1997/09/22 21:50:04 thorpej Exp $ */
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/*
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* Copyright (c) 1982, 1986, 1993, 1994
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* The Regents of the University of California. All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by the University of
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* California, Berkeley and its contributors.
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* 4. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* @(#)tcp_var.h 8.3 (Berkeley) 4/10/94
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*/
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/*
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* Kernel variables for tcp.
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*/
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/*
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* Tcp control block, one per tcp; fields:
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*/
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struct tcpcb {
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struct ipqehead segq; /* sequencing queue */
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short t_state; /* state of this connection */
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short t_timer[TCPT_NTIMERS]; /* tcp timers */
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short t_rxtshift; /* log(2) of rexmt exp. backoff */
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short t_rxtcur; /* current retransmit value */
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short t_dupacks; /* consecutive dup acks recd */
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u_short t_maxseg; /* peer's maximum segment size */
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u_short t_ourmss; /* our's maximum segment size */
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char t_force; /* 1 if forcing out a byte */
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u_short t_flags;
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#define TF_ACKNOW 0x0001 /* ack peer immediately */
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#define TF_DELACK 0x0002 /* ack, but try to delay it */
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#define TF_NODELAY 0x0004 /* don't delay packets to coalesce */
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#define TF_NOOPT 0x0008 /* don't use tcp options */
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#define TF_SENTFIN 0x0010 /* have sent FIN */
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#define TF_REQ_SCALE 0x0020 /* have/will request window scaling */
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#define TF_RCVD_SCALE 0x0040 /* other side has requested scaling */
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#define TF_REQ_TSTMP 0x0080 /* have/will request timestamps */
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#define TF_RCVD_TSTMP 0x0100 /* a timestamp was received in SYN */
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#define TF_SACK_PERMIT 0x0200 /* other side said I could SACK */
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struct tcpiphdr *t_template; /* skeletal packet for transmit */
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struct inpcb *t_inpcb; /* back pointer to internet pcb */
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/*
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* The following fields are used as in the protocol specification.
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* See RFC783, Dec. 1981, page 21.
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*/
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/* send sequence variables */
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tcp_seq snd_una; /* send unacknowledged */
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tcp_seq snd_nxt; /* send next */
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tcp_seq snd_up; /* send urgent pointer */
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tcp_seq snd_wl1; /* window update seg seq number */
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tcp_seq snd_wl2; /* window update seg ack number */
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tcp_seq iss; /* initial send sequence number */
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u_long snd_wnd; /* send window */
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/* receive sequence variables */
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u_long rcv_wnd; /* receive window */
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tcp_seq rcv_nxt; /* receive next */
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tcp_seq rcv_up; /* receive urgent pointer */
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tcp_seq irs; /* initial receive sequence number */
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/*
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* Additional variables for this implementation.
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*/
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/* receive variables */
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tcp_seq rcv_adv; /* advertised window */
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/* retransmit variables */
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tcp_seq snd_max; /* highest sequence number sent;
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* used to recognize retransmits
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*/
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/* congestion control (for slow start, source quench, retransmit after loss) */
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u_long snd_cwnd; /* congestion-controlled window */
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u_long snd_ssthresh; /* snd_cwnd size threshhold for
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* for slow start exponential to
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* linear switch
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*/
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/*
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* transmit timing stuff. See below for scale of srtt and rttvar.
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* "Variance" is actually smoothed difference.
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*/
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short t_idle; /* inactivity time */
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short t_rtt; /* round trip time */
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tcp_seq t_rtseq; /* sequence number being timed */
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short t_srtt; /* smoothed round-trip time */
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short t_rttvar; /* variance in round-trip time */
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short t_rttmin; /* minimum rtt allowed */
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u_long max_sndwnd; /* largest window peer has offered */
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/* out-of-band data */
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char t_oobflags; /* have some */
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char t_iobc; /* input character */
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#define TCPOOB_HAVEDATA 0x01
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#define TCPOOB_HADDATA 0x02
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short t_softerror; /* possible error not yet reported */
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/* RFC 1323 variables */
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u_char snd_scale; /* window scaling for send window */
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u_char rcv_scale; /* window scaling for recv window */
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u_char request_r_scale; /* pending window scaling */
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u_char requested_s_scale;
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u_int32_t ts_recent; /* timestamp echo data */
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u_int32_t ts_recent_age; /* when last updated */
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tcp_seq last_ack_sent;
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/* TUBA stuff */
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caddr_t t_tuba_pcb; /* next level down pcb for TCP over z */
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};
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/*
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* Handy way of passing around TCP option info.
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*/
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struct tcp_opt_info {
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int ts_present;
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u_int32_t ts_val;
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u_int32_t ts_ecr;
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u_int16_t maxseg;
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};
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/*
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* This structure should not exceed 32 bytes.
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* XXX On the Alpha, it's already 36-bytes, which rounds to 40.
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* XXX Need to eliminate the pointer.
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*
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* XXX We've blown 32 bytes on non-Alpha systems, too, since we're
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* XXX storing the maxseg we advertised to the peer. Should we
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* XXX create another malloc bucket? Should we care?
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*/
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struct syn_cache {
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struct syn_cache *sc_next;
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u_int32_t sc_tstmp : 1,
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sc_hash : 31;
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struct in_addr sc_src;
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struct in_addr sc_dst;
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tcp_seq sc_irs;
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tcp_seq sc_iss;
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u_int16_t sc_sport;
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u_int16_t sc_dport;
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u_int16_t sc_peermaxseg;
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u_int16_t sc_ourmaxseg;
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u_int8_t sc_timer;
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u_int8_t sc_request_r_scale : 4,
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sc_requested_s_scale : 4;
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};
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struct syn_cache_head {
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struct syn_cache *sch_first; /* First entry in the bucket */
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struct syn_cache *sch_last; /* Last entry in the bucket */
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struct syn_cache_head *sch_headq; /* The next non-empty bucket */
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int16_t sch_timer_sum; /* Total time in this bucket */
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u_int16_t sch_length; /* @ # elements in bucket */
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};
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#define intotcpcb(ip) ((struct tcpcb *)(ip)->inp_ppcb)
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#define sototcpcb(so) (intotcpcb(sotoinpcb(so)))
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/*
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* The smoothed round-trip time and estimated variance
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* are stored as fixed point numbers scaled by the values below.
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* For convenience, these scales are also used in smoothing the average
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* (smoothed = (1/scale)sample + ((scale-1)/scale)smoothed).
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* With these scales, srtt has 3 bits to the right of the binary point,
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* and thus an "ALPHA" of 0.875. rttvar has 2 bits to the right of the
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* binary point, and is smoothed with an ALPHA of 0.75.
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*/
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#define TCP_RTT_SHIFT 3 /* shift for srtt; 3 bits frac. */
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#define TCP_RTTVAR_SHIFT 2 /* multiplier for rttvar; 2 bits */
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/*
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* The initial retransmission should happen at rtt + 4 * rttvar.
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* Because of the way we do the smoothing, srtt and rttvar
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* will each average +1/2 tick of bias. When we compute
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* the retransmit timer, we want 1/2 tick of rounding and
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* 1 extra tick because of +-1/2 tick uncertainty in the
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* firing of the timer. The bias will give us exactly the
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* 1.5 tick we need. But, because the bias is
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* statistical, we have to test that we don't drop below
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* the minimum feasible timer (which is 2 ticks).
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* This macro assumes that the value of 1<<TCP_RTTVAR_SHIFT
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* is the same as the multiplier for rttvar.
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*/
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#define TCP_REXMTVAL(tp) \
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((((tp)->t_srtt >> TCP_RTT_SHIFT) + (tp)->t_rttvar) >> 2)
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/*
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* TCP statistics.
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* Many of these should be kept per connection,
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* but that's inconvenient at the moment.
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*/
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struct tcpstat {
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u_long tcps_connattempt; /* connections initiated */
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u_long tcps_accepts; /* connections accepted */
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u_long tcps_connects; /* connections established */
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u_long tcps_drops; /* connections dropped */
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u_long tcps_conndrops; /* embryonic connections dropped */
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u_long tcps_closed; /* conn. closed (includes drops) */
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u_long tcps_segstimed; /* segs where we tried to get rtt */
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u_long tcps_rttupdated; /* times we succeeded */
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u_long tcps_delack; /* delayed acks sent */
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u_long tcps_timeoutdrop; /* conn. dropped in rxmt timeout */
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u_long tcps_rexmttimeo; /* retransmit timeouts */
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u_long tcps_persisttimeo; /* persist timeouts */
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u_long tcps_keeptimeo; /* keepalive timeouts */
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u_long tcps_keepprobe; /* keepalive probes sent */
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u_long tcps_keepdrops; /* connections dropped in keepalive */
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u_long tcps_sndtotal; /* total packets sent */
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u_long tcps_sndpack; /* data packets sent */
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u_long tcps_sndbyte; /* data bytes sent */
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u_long tcps_sndrexmitpack; /* data packets retransmitted */
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u_long tcps_sndrexmitbyte; /* data bytes retransmitted */
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u_long tcps_sndacks; /* ack-only packets sent */
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u_long tcps_sndprobe; /* window probes sent */
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u_long tcps_sndurg; /* packets sent with URG only */
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u_long tcps_sndwinup; /* window update-only packets sent */
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u_long tcps_sndctrl; /* control (SYN|FIN|RST) packets sent */
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u_long tcps_rcvtotal; /* total packets received */
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u_long tcps_rcvpack; /* packets received in sequence */
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u_long tcps_rcvbyte; /* bytes received in sequence */
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u_long tcps_rcvbadsum; /* packets received with ccksum errs */
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u_long tcps_rcvbadoff; /* packets received with bad offset */
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u_long tcps_rcvmemdrop; /* packets dropped for lack of memory */
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u_long tcps_rcvshort; /* packets received too short */
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u_long tcps_rcvduppack; /* duplicate-only packets received */
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u_long tcps_rcvdupbyte; /* duplicate-only bytes received */
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u_long tcps_rcvpartduppack; /* packets with some duplicate data */
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u_long tcps_rcvpartdupbyte; /* dup. bytes in part-dup. packets */
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u_long tcps_rcvoopack; /* out-of-order packets received */
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u_long tcps_rcvoobyte; /* out-of-order bytes received */
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u_long tcps_rcvpackafterwin; /* packets with data after window */
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u_long tcps_rcvbyteafterwin; /* bytes rcvd after window */
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u_long tcps_rcvafterclose; /* packets rcvd after "close" */
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u_long tcps_rcvwinprobe; /* rcvd window probe packets */
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u_long tcps_rcvdupack; /* rcvd duplicate acks */
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u_long tcps_rcvacktoomuch; /* rcvd acks for unsent data */
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u_long tcps_rcvackpack; /* rcvd ack packets */
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u_long tcps_rcvackbyte; /* bytes acked by rcvd acks */
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u_long tcps_rcvwinupd; /* rcvd window update packets */
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u_long tcps_pawsdrop; /* segments dropped due to PAWS */
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u_long tcps_predack; /* times hdr predict ok for acks */
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u_long tcps_preddat; /* times hdr predict ok for data pkts */
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u_long tcps_pcbhashmiss; /* input packets missing pcb hash */
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u_long tcps_noport; /* no socket on port */
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u_long tcps_badsyn; /* received ack for which we have
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no SYN in compressed state */
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/* These statistics deal with the SYN cache. */
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u_long tcps_sc_added; /* # of entries added */
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u_long tcps_sc_completed; /* # of connections completed */
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u_long tcps_sc_timed_out; /* # of entries timed out */
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u_long tcps_sc_overflowed; /* # dropped due to overflow */
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u_long tcps_sc_reset; /* # dropped due to RST */
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u_long tcps_sc_unreach; /* # dropped due to ICMP unreach */
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u_long tcps_sc_bucketoverflow; /* # dropped due to bucket overflow */
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u_long tcps_sc_aborted; /* # of entries aborted (no mem) */
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u_long tcps_sc_dupesyn; /* # of duplicate SYNs received */
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u_long tcps_sc_dropped; /* # of SYNs dropped (no route/mem) */
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u_long tcps_sc_collisions; /* # of hash collisions */
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};
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/*
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* Names for TCP sysctl objects.
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*/
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#define TCPCTL_RFC1323 1 /* RFC1323 timestamps/scaling */
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#define TCPCTL_SENDSPACE 2 /* default send buffer */
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#define TCPCTL_RECVSPACE 3 /* default recv buffer */
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#define TCPCTL_MSSDFLT 4 /* default seg size */
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#define TCPCTL_SYN_CACHE_LIMIT 5 /* max size of comp. state engine */
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#define TCPCTL_SYN_BUCKET_LIMIT 6 /* max size of hash bucket */
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#define TCPCTL_SYN_CACHE_INTER 7 /* interval of comp. state timer */
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#define TCPCTL_MAXID 8
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#define TCPCTL_NAMES { \
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{ 0, 0 }, \
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{ "rfc1323", CTLTYPE_INT }, \
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{ "sendspace", CTLTYPE_INT }, \
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{ "recvspace", CTLTYPE_INT }, \
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{ "mssdflt", CTLTYPE_INT }, \
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{ "syn_cache_limit", CTLTYPE_INT }, \
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{ "syn_bucket_limit", CTLTYPE_INT }, \
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{ "syn_cache_interval", CTLTYPE_INT },\
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}
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#ifdef _KERNEL
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struct inpcbtable tcbtable; /* head of queue of active tcpcb's */
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struct tcpstat tcpstat; /* tcp statistics */
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u_int32_t tcp_now; /* for RFC 1323 timestamps */
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extern int tcp_do_rfc1323; /* enabled/disabled? */
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extern int tcp_mssdflt; /* default seg size */
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extern int tcp_syn_cache_limit; /* max entries for compressed state engine */
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extern int tcp_syn_bucket_limit;/* max entries per hash bucket */
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extern int tcp_syn_cache_interval; /* compressed state timer */
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extern int tcp_syn_cache_size;
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extern int tcp_syn_cache_timeo;
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extern struct syn_cache_head tcp_syn_cache[], *tcp_syn_cache_first;
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extern u_long syn_cache_count;
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int tcp_attach __P((struct socket *));
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void tcp_canceltimers __P((struct tcpcb *));
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struct tcpcb *
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tcp_close __P((struct tcpcb *));
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void *tcp_ctlinput __P((int, struct sockaddr *, void *));
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int tcp_ctloutput __P((int, struct socket *, int, int, struct mbuf **));
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struct tcpcb *
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tcp_disconnect __P((struct tcpcb *));
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struct tcpcb *
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tcp_drop __P((struct tcpcb *, int));
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void tcp_dooptions __P((struct tcpcb *,
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u_char *, int, struct tcpiphdr *, struct tcp_opt_info *));
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void tcp_drain __P((void));
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void tcp_established __P((struct tcpcb *));
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void tcp_fasttimo __P((void));
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void tcp_init __P((void));
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void tcp_input __P((struct mbuf *, ...));
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int tcp_mss_to_advertise __P((const struct tcpcb *));
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void tcp_mss_from_peer __P((struct tcpcb *, int));
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struct tcpcb *
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tcp_newtcpcb __P((struct inpcb *));
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void tcp_notify __P((struct inpcb *, int));
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int tcp_output __P((struct tcpcb *));
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void tcp_pulloutofband __P((struct socket *,
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struct tcpiphdr *, struct mbuf *));
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void tcp_quench __P((struct inpcb *, int));
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int tcp_reass __P((struct tcpcb *, struct tcpiphdr *, struct mbuf *));
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int tcp_respond __P((struct tcpcb *,
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struct tcpiphdr *, struct mbuf *, tcp_seq, tcp_seq, int));
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void tcp_rmx_rtt __P((struct tcpcb *));
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void tcp_setpersist __P((struct tcpcb *));
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void tcp_slowtimo __P((void));
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struct tcpiphdr *
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tcp_template __P((struct tcpcb *));
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struct tcpcb *
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tcp_timers __P((struct tcpcb *, int));
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void tcp_trace __P((int, int, struct tcpcb *, struct tcpiphdr *, int));
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struct tcpcb *
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tcp_usrclosed __P((struct tcpcb *));
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int tcp_sysctl __P((int *, u_int, void *, size_t *, void *, size_t));
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int tcp_usrreq __P((struct socket *,
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int, struct mbuf *, struct mbuf *, struct mbuf *, struct proc *));
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void tcp_xmit_timer __P((struct tcpcb *, int));
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int syn_cache_add __P((struct socket *, struct mbuf *, u_char *,
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int, struct tcp_opt_info *));
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void syn_cache_unreach __P((struct ip *, struct tcphdr *));
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struct socket *
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syn_cache_get __P((struct socket *so, struct mbuf *));
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void syn_cache_insert __P((struct syn_cache *, struct syn_cache ***,
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struct syn_cache_head **));
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struct syn_cache *
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syn_cache_lookup __P((struct tcpiphdr *, struct syn_cache ***,
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struct syn_cache_head **));
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void syn_cache_reset __P((struct tcpiphdr *));
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int syn_cache_respond __P((struct syn_cache *, struct mbuf *,
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register struct tcpiphdr *, long, u_long));
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void syn_cache_timer __P((int));
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#endif
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