freebsd-dev/sys/netinet/tcp_var.h
Andre Oppermann c94c54e4df Remove RFC1644 T/TCP support from the TCP side of the network stack.
A complete rationale and discussion is given in this message
and the resulting discussion:

 http://docs.freebsd.org/cgi/mid.cgi?4177C8AD.6060706

Note that this commit removes only the functional part of T/TCP
from the tcp_* related functions in the kernel.  Other features
introduced with RFC1644 are left intact (socket layer changes,
sendmsg(2) on connection oriented protocols)  and are meant to
be reused by a simpler and less intrusive reimplemention of the
previous T/TCP functionality.

Discussed on:	-arch
2004-11-02 22:22:22 +00:00

594 lines
23 KiB
C

/*
* Copyright (c) 1982, 1986, 1993, 1994, 1995
* The Regents of the University of California. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 4. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* @(#)tcp_var.h 8.4 (Berkeley) 5/24/95
* $FreeBSD$
*/
#ifndef _NETINET_TCP_VAR_H_
#define _NETINET_TCP_VAR_H_
#include <netinet/tcp.h>
/*
* Kernel variables for tcp.
*/
extern int tcp_do_rfc1323;
/* TCP segment queue entry */
struct tseg_qent {
LIST_ENTRY(tseg_qent) tqe_q;
int tqe_len; /* TCP segment data length */
struct tcphdr *tqe_th; /* a pointer to tcp header */
struct mbuf *tqe_m; /* mbuf contains packet */
};
LIST_HEAD(tsegqe_head, tseg_qent);
extern int tcp_reass_qsize;
extern struct uma_zone *tcp_reass_zone;
struct sackblk {
tcp_seq start; /* start seq no. of sack block */
tcp_seq end; /* end seq no. */
};
struct sackhole {
tcp_seq start; /* start seq no. of hole */
tcp_seq end; /* end seq no. */
tcp_seq rxmit; /* next seq. no in hole to be retransmitted */
struct sackhole *next; /* next in list */
};
struct tcptemp {
u_char tt_ipgen[40]; /* the size must be of max ip header, now IPv6 */
struct tcphdr tt_t;
};
#define tcp6cb tcpcb /* for KAME src sync over BSD*'s */
/*
* Tcp control block, one per tcp; fields:
* Organized for 16 byte cacheline efficiency.
*/
struct tcpcb {
struct tsegqe_head t_segq; /* segment reassembly queue */
int t_segqlen; /* segment reassembly queue length */
int t_dupacks; /* consecutive dup acks recd */
struct callout *tt_rexmt; /* retransmit timer */
struct callout *tt_persist; /* retransmit persistence */
struct callout *tt_keep; /* keepalive */
struct callout *tt_2msl; /* 2*msl TIME_WAIT timer */
struct callout *tt_delack; /* delayed ACK timer */
struct inpcb *t_inpcb; /* back pointer to internet pcb */
int t_state; /* state of this connection */
u_int t_flags;
#define TF_ACKNOW 0x000001 /* ack peer immediately */
#define TF_DELACK 0x000002 /* ack, but try to delay it */
#define TF_NODELAY 0x000004 /* don't delay packets to coalesce */
#define TF_NOOPT 0x000008 /* don't use tcp options */
#define TF_SENTFIN 0x000010 /* have sent FIN */
#define TF_REQ_SCALE 0x000020 /* have/will request window scaling */
#define TF_RCVD_SCALE 0x000040 /* other side has requested scaling */
#define TF_REQ_TSTMP 0x000080 /* have/will request timestamps */
#define TF_RCVD_TSTMP 0x000100 /* a timestamp was received in SYN */
#define TF_SACK_PERMIT 0x000200 /* other side said I could SACK */
#define TF_NEEDSYN 0x000400 /* send SYN (implicit state) */
#define TF_NEEDFIN 0x000800 /* send FIN (implicit state) */
#define TF_NOPUSH 0x001000 /* don't push */
#define TF_MORETOCOME 0x010000 /* More data to be appended to sock */
#define TF_LQ_OVERFLOW 0x020000 /* listen queue overflow */
#define TF_LASTIDLE 0x040000 /* connection was previously idle */
#define TF_RXWIN0SENT 0x080000 /* sent a receiver win 0 in response */
#define TF_FASTRECOVERY 0x100000 /* in NewReno Fast Recovery */
#define TF_WASFRECOVERY 0x200000 /* was in NewReno Fast Recovery */
#define TF_SIGNATURE 0x400000 /* require MD5 digests (RFC2385) */
int t_force; /* 1 if forcing out a byte */
tcp_seq snd_una; /* send unacknowledged */
tcp_seq snd_max; /* highest sequence number sent;
* used to recognize retransmits
*/
tcp_seq snd_nxt; /* send next */
tcp_seq snd_up; /* send urgent pointer */
tcp_seq snd_wl1; /* window update seg seq number */
tcp_seq snd_wl2; /* window update seg ack number */
tcp_seq iss; /* initial send sequence number */
tcp_seq irs; /* initial receive sequence number */
tcp_seq rcv_nxt; /* receive next */
tcp_seq rcv_adv; /* advertised window */
u_long rcv_wnd; /* receive window */
tcp_seq rcv_up; /* receive urgent pointer */
u_long snd_wnd; /* send window */
u_long snd_cwnd; /* congestion-controlled window */
u_long snd_bwnd; /* bandwidth-controlled window */
u_long snd_ssthresh; /* snd_cwnd size threshold for
* for slow start exponential to
* linear switch
*/
u_long snd_bandwidth; /* calculated bandwidth or 0 */
tcp_seq snd_recover; /* for use in NewReno Fast Recovery */
u_int t_maxopd; /* mss plus options */
u_long t_rcvtime; /* inactivity time */
u_long t_starttime; /* time connection was established */
int t_rtttime; /* round trip time */
tcp_seq t_rtseq; /* sequence number being timed */
int t_bw_rtttime; /* used for bandwidth calculation */
tcp_seq t_bw_rtseq; /* used for bandwidth calculation */
int t_rxtcur; /* current retransmit value (ticks) */
u_int t_maxseg; /* maximum segment size */
int t_srtt; /* smoothed round-trip time */
int t_rttvar; /* variance in round-trip time */
int t_rxtshift; /* log(2) of rexmt exp. backoff */
u_int t_rttmin; /* minimum rtt allowed */
u_int t_rttbest; /* best rtt we've seen */
u_long t_rttupdated; /* number of times rtt sampled */
u_long max_sndwnd; /* largest window peer has offered */
int t_softerror; /* possible error not yet reported */
/* out-of-band data */
char t_oobflags; /* have some */
char t_iobc; /* input character */
#define TCPOOB_HAVEDATA 0x01
#define TCPOOB_HADDATA 0x02
/* RFC 1323 variables */
u_char snd_scale; /* window scaling for send window */
u_char rcv_scale; /* window scaling for recv window */
u_char request_r_scale; /* pending window scaling */
u_char requested_s_scale;
u_long ts_recent; /* timestamp echo data */
u_long ts_recent_age; /* when last updated */
tcp_seq last_ack_sent;
/* experimental */
u_long snd_cwnd_prev; /* cwnd prior to retransmit */
u_long snd_ssthresh_prev; /* ssthresh prior to retransmit */
tcp_seq snd_recover_prev; /* snd_recover prior to retransmit */
u_long t_badrxtwin; /* window for retransmit recovery */
u_char snd_limited; /* segments limited transmitted */
/* anti DoS counters */
u_long rcv_second; /* start of interval second */
u_long rcv_pps; /* received packets per second */
u_long rcv_byps; /* received bytes per second */
/* SACK related state */
int sack_enable; /* enable SACK for this connection */
int snd_numholes; /* number of holes seen by sender */
struct sackhole *snd_holes; /* linked list of holes (sorted) */
tcp_seq rcv_laststart; /* start of last segment recd. */
tcp_seq rcv_lastend; /* end of ... */
tcp_seq rcv_lastsack; /* last seq number(+1) sack'd by rcv'r*/
int rcv_numsacks; /* # distinct sack blks present */
struct sackblk sackblks[MAX_SACK_BLKS]; /* seq nos. of sack blocks */
tcp_seq sack_newdata; /* New data xmitted in this recovery
episode starts at this seq number */
};
#define IN_FASTRECOVERY(tp) (tp->t_flags & TF_FASTRECOVERY)
#define ENTER_FASTRECOVERY(tp) tp->t_flags |= TF_FASTRECOVERY
#define EXIT_FASTRECOVERY(tp) tp->t_flags &= ~TF_FASTRECOVERY
#ifdef TCP_SIGNATURE
/*
* Defines which are needed by the xform_tcp module and tcp_[in|out]put
* for SADB verification and lookup.
*/
#define TCP_SIGLEN 16 /* length of computed digest in bytes */
#define TCP_KEYLEN_MIN 1 /* minimum length of TCP-MD5 key */
#define TCP_KEYLEN_MAX 80 /* maximum length of TCP-MD5 key */
/*
* Only a single SA per host may be specified at this time. An SPI is
* needed in order for the KEY_ALLOCSA() lookup to work.
*/
#define TCP_SIG_SPI 0x1000
#endif /* TCP_SIGNATURE */
/*
* Structure to hold TCP options that are only used during segment
* processing (in tcp_input), but not held in the tcpcb.
* It's basically used to reduce the number of parameters
* to tcp_dooptions.
*/
struct tcpopt {
u_long to_flags; /* which options are present */
#define TOF_TS 0x0001 /* timestamp */
#define TOF_MSS 0x0010
#define TOF_SCALE 0x0020
#define TOF_SIGNATURE 0x0040 /* signature option present */
#define TOF_SIGLEN 0x0080 /* signature length valid (RFC2385) */
#define TOF_SACK 0x0100 /* Peer sent SACK option */
u_int32_t to_tsval;
u_int32_t to_tsecr;
u_int16_t to_mss;
u_int8_t to_requested_s_scale;
u_int8_t to_pad;
};
#ifdef _NETINET_IN_PCB_H_
struct syncache {
inp_gen_t sc_inp_gencnt; /* pointer check */
struct tcpcb *sc_tp; /* tcb for listening socket */
struct mbuf *sc_ipopts; /* source route */
struct in_conninfo sc_inc; /* addresses */
u_int32_t sc_tsrecent;
u_int32_t sc_flowlabel; /* IPv6 flowlabel */
tcp_seq sc_irs; /* seq from peer */
tcp_seq sc_iss; /* our ISS */
u_long sc_rxttime; /* retransmit time */
u_int16_t sc_rxtslot; /* retransmit counter */
u_int16_t sc_peer_mss; /* peer's MSS */
u_int16_t sc_wnd; /* advertised window */
u_int8_t sc_requested_s_scale:4,
sc_request_r_scale:4;
u_int8_t sc_flags;
#define SCF_NOOPT 0x01 /* no TCP options */
#define SCF_WINSCALE 0x02 /* negotiated window scaling */
#define SCF_TIMESTAMP 0x04 /* negotiated timestamps */
#define SCF_UNREACH 0x10 /* icmp unreachable received */
#define SCF_SIGNATURE 0x20 /* send MD5 digests */
#define SCF_SACK 0x80 /* send SACK option */
TAILQ_ENTRY(syncache) sc_hash;
TAILQ_ENTRY(syncache) sc_timerq;
};
struct syncache_head {
TAILQ_HEAD(, syncache) sch_bucket;
u_int sch_length;
};
#else
struct in_conninfo;
#endif /* _NETINET_IN_PCB_H_ */
struct hc_metrics_lite { /* must stay in sync with hc_metrics */
u_long rmx_mtu; /* MTU for this path */
u_long rmx_ssthresh; /* outbound gateway buffer limit */
u_long rmx_rtt; /* estimated round trip time */
u_long rmx_rttvar; /* estimated rtt variance */
u_long rmx_bandwidth; /* estimated bandwidth */
u_long rmx_cwnd; /* congestion window */
u_long rmx_sendpipe; /* outbound delay-bandwidth product */
u_long rmx_recvpipe; /* inbound delay-bandwidth product */
};
struct tcptw {
struct inpcb *tw_inpcb; /* XXX back pointer to internet pcb */
tcp_seq snd_nxt;
tcp_seq rcv_nxt;
tcp_seq iss;
tcp_seq irs;
u_short last_win; /* cached window value */
u_short tw_so_options; /* copy of so_options */
struct ucred *tw_cred; /* user credentials */
u_long t_recent;
u_long t_starttime;
int tw_time;
LIST_ENTRY(tcptw) tw_2msl;
};
#define intotcpcb(ip) ((struct tcpcb *)(ip)->inp_ppcb)
#define intotw(ip) ((struct tcptw *)(ip)->inp_ppcb)
#define sototcpcb(so) (intotcpcb(sotoinpcb(so)))
/*
* The smoothed round-trip time and estimated variance
* are stored as fixed point numbers scaled by the values below.
* For convenience, these scales are also used in smoothing the average
* (smoothed = (1/scale)sample + ((scale-1)/scale)smoothed).
* With these scales, srtt has 3 bits to the right of the binary point,
* and thus an "ALPHA" of 0.875. rttvar has 2 bits to the right of the
* binary point, and is smoothed with an ALPHA of 0.75.
*/
#define TCP_RTT_SCALE 32 /* multiplier for srtt; 3 bits frac. */
#define TCP_RTT_SHIFT 5 /* shift for srtt; 3 bits frac. */
#define TCP_RTTVAR_SCALE 16 /* multiplier for rttvar; 2 bits */
#define TCP_RTTVAR_SHIFT 4 /* shift for rttvar; 2 bits */
#define TCP_DELTA_SHIFT 2 /* see tcp_input.c */
/*
* The initial retransmission should happen at rtt + 4 * rttvar.
* Because of the way we do the smoothing, srtt and rttvar
* will each average +1/2 tick of bias. When we compute
* the retransmit timer, we want 1/2 tick of rounding and
* 1 extra tick because of +-1/2 tick uncertainty in the
* firing of the timer. The bias will give us exactly the
* 1.5 tick we need. But, because the bias is
* statistical, we have to test that we don't drop below
* the minimum feasible timer (which is 2 ticks).
* This version of the macro adapted from a paper by Lawrence
* Brakmo and Larry Peterson which outlines a problem caused
* by insufficient precision in the original implementation,
* which results in inappropriately large RTO values for very
* fast networks.
*/
#define TCP_REXMTVAL(tp) \
max((tp)->t_rttmin, (((tp)->t_srtt >> (TCP_RTT_SHIFT - TCP_DELTA_SHIFT)) \
+ (tp)->t_rttvar) >> TCP_DELTA_SHIFT)
/*
* TCP statistics.
* Many of these should be kept per connection,
* but that's inconvenient at the moment.
*/
struct tcpstat {
u_long tcps_connattempt; /* connections initiated */
u_long tcps_accepts; /* connections accepted */
u_long tcps_connects; /* connections established */
u_long tcps_drops; /* connections dropped */
u_long tcps_conndrops; /* embryonic connections dropped */
u_long tcps_minmssdrops; /* average minmss too low drops */
u_long tcps_closed; /* conn. closed (includes drops) */
u_long tcps_segstimed; /* segs where we tried to get rtt */
u_long tcps_rttupdated; /* times we succeeded */
u_long tcps_delack; /* delayed acks sent */
u_long tcps_timeoutdrop; /* conn. dropped in rxmt timeout */
u_long tcps_rexmttimeo; /* retransmit timeouts */
u_long tcps_persisttimeo; /* persist timeouts */
u_long tcps_keeptimeo; /* keepalive timeouts */
u_long tcps_keepprobe; /* keepalive probes sent */
u_long tcps_keepdrops; /* connections dropped in keepalive */
u_long tcps_sndtotal; /* total packets sent */
u_long tcps_sndpack; /* data packets sent */
u_long tcps_sndbyte; /* data bytes sent */
u_long tcps_sndrexmitpack; /* data packets retransmitted */
u_long tcps_sndrexmitbyte; /* data bytes retransmitted */
u_long tcps_sndrexmitbad; /* unnecessary packet retransmissions */
u_long tcps_sndacks; /* ack-only packets sent */
u_long tcps_sndprobe; /* window probes sent */
u_long tcps_sndurg; /* packets sent with URG only */
u_long tcps_sndwinup; /* window update-only packets sent */
u_long tcps_sndctrl; /* control (SYN|FIN|RST) packets sent */
u_long tcps_rcvtotal; /* total packets received */
u_long tcps_rcvpack; /* packets received in sequence */
u_long tcps_rcvbyte; /* bytes received in sequence */
u_long tcps_rcvbadsum; /* packets received with ccksum errs */
u_long tcps_rcvbadoff; /* packets received with bad offset */
u_long tcps_rcvmemdrop; /* packets dropped for lack of memory */
u_long tcps_rcvshort; /* packets received too short */
u_long tcps_rcvduppack; /* duplicate-only packets received */
u_long tcps_rcvdupbyte; /* duplicate-only bytes received */
u_long tcps_rcvpartduppack; /* packets with some duplicate data */
u_long tcps_rcvpartdupbyte; /* dup. bytes in part-dup. packets */
u_long tcps_rcvoopack; /* out-of-order packets received */
u_long tcps_rcvoobyte; /* out-of-order bytes received */
u_long tcps_rcvpackafterwin; /* packets with data after window */
u_long tcps_rcvbyteafterwin; /* bytes rcvd after window */
u_long tcps_rcvafterclose; /* packets rcvd after "close" */
u_long tcps_rcvwinprobe; /* rcvd window probe packets */
u_long tcps_rcvdupack; /* rcvd duplicate acks */
u_long tcps_rcvacktoomuch; /* rcvd acks for unsent data */
u_long tcps_rcvackpack; /* rcvd ack packets */
u_long tcps_rcvackbyte; /* bytes acked by rcvd acks */
u_long tcps_rcvwinupd; /* rcvd window update packets */
u_long tcps_pawsdrop; /* segments dropped due to PAWS */
u_long tcps_predack; /* times hdr predict ok for acks */
u_long tcps_preddat; /* times hdr predict ok for data pkts */
u_long tcps_pcbcachemiss;
u_long tcps_cachedrtt; /* times cached RTT in route updated */
u_long tcps_cachedrttvar; /* times cached rttvar updated */
u_long tcps_cachedssthresh; /* times cached ssthresh updated */
u_long tcps_usedrtt; /* times RTT initialized from route */
u_long tcps_usedrttvar; /* times RTTVAR initialized from rt */
u_long tcps_usedssthresh; /* times ssthresh initialized from rt*/
u_long tcps_persistdrop; /* timeout in persist state */
u_long tcps_badsyn; /* bogus SYN, e.g. premature ACK */
u_long tcps_mturesent; /* resends due to MTU discovery */
u_long tcps_listendrop; /* listen queue overflows */
u_long tcps_badrst; /* ignored RSTs in the window */
u_long tcps_sc_added; /* entry added to syncache */
u_long tcps_sc_retransmitted; /* syncache entry was retransmitted */
u_long tcps_sc_dupsyn; /* duplicate SYN packet */
u_long tcps_sc_dropped; /* could not reply to packet */
u_long tcps_sc_completed; /* successful extraction of entry */
u_long tcps_sc_bucketoverflow; /* syncache per-bucket limit hit */
u_long tcps_sc_cacheoverflow; /* syncache cache limit hit */
u_long tcps_sc_reset; /* RST removed entry from syncache */
u_long tcps_sc_stale; /* timed out or listen socket gone */
u_long tcps_sc_aborted; /* syncache entry aborted */
u_long tcps_sc_badack; /* removed due to bad ACK */
u_long tcps_sc_unreach; /* ICMP unreachable received */
u_long tcps_sc_zonefail; /* zalloc() failed */
u_long tcps_sc_sendcookie; /* SYN cookie sent */
u_long tcps_sc_recvcookie; /* SYN cookie received */
u_long tcps_hc_added; /* entry added to hostcache */
u_long tcps_hc_bucketoverflow; /* hostcache per bucket limit hit */
/* SACK related stats */
u_long tcps_sack_recovery_episode; /* SACK recovery episodes */
u_long tcps_sack_rexmits; /* SACK rexmit segments */
u_long tcps_sack_rexmit_bytes; /* SACK rexmit bytes */
u_long tcps_sack_rcv_blocks; /* SACK blocks (options) received */
u_long tcps_sack_send_blocks; /* SACK blocks (options) sent */
};
/*
* TCB structure exported to user-land via sysctl(3).
* Evil hack: declare only if in_pcb.h and sys/socketvar.h have been
* included. Not all of our clients do.
*/
#if defined(_NETINET_IN_PCB_H_) && defined(_SYS_SOCKETVAR_H_)
struct xtcpcb {
size_t xt_len;
struct inpcb xt_inp;
struct tcpcb xt_tp;
struct xsocket xt_socket;
u_quad_t xt_alignment_hack;
};
#endif
/*
* Names for TCP sysctl objects
*/
#define TCPCTL_DO_RFC1323 1 /* use RFC-1323 extensions */
#define TCPCTL_MSSDFLT 3 /* MSS default */
#define TCPCTL_STATS 4 /* statistics (read-only) */
#define TCPCTL_RTTDFLT 5 /* default RTT estimate */
#define TCPCTL_KEEPIDLE 6 /* keepalive idle timer */
#define TCPCTL_KEEPINTVL 7 /* interval to send keepalives */
#define TCPCTL_SENDSPACE 8 /* send buffer space */
#define TCPCTL_RECVSPACE 9 /* receive buffer space */
#define TCPCTL_KEEPINIT 10 /* timeout for establishing syn */
#define TCPCTL_PCBLIST 11 /* list of all outstanding PCBs */
#define TCPCTL_DELACKTIME 12 /* time before sending delayed ACK */
#define TCPCTL_V6MSSDFLT 13 /* MSS default for IPv6 */
#define TCPCTL_SACK 14 /* Selective Acknowledgement,rfc 2018 */
#define TCPCTL_MAXID 15
#define TCPCTL_NAMES { \
{ 0, 0 }, \
{ "rfc1323", CTLTYPE_INT }, \
{ "mssdflt", CTLTYPE_INT }, \
{ "stats", CTLTYPE_STRUCT }, \
{ "rttdflt", CTLTYPE_INT }, \
{ "keepidle", CTLTYPE_INT }, \
{ "keepintvl", CTLTYPE_INT }, \
{ "sendspace", CTLTYPE_INT }, \
{ "recvspace", CTLTYPE_INT }, \
{ "keepinit", CTLTYPE_INT }, \
{ "pcblist", CTLTYPE_STRUCT }, \
{ "delacktime", CTLTYPE_INT }, \
{ "v6mssdflt", CTLTYPE_INT }, \
{ "maxid", CTLTYPE_INT }, \
}
#ifdef _KERNEL
#ifdef SYSCTL_DECL
SYSCTL_DECL(_net_inet_tcp);
SYSCTL_DECL(_net_inet_tcp_sack);
#endif
extern struct inpcbhead tcb; /* head of queue of active tcpcb's */
extern struct inpcbinfo tcbinfo;
extern struct tcpstat tcpstat; /* tcp statistics */
extern int tcp_mssdflt; /* XXX */
extern int tcp_minmss;
extern int tcp_minmssoverload;
extern int tcp_delack_enabled;
extern int tcp_do_newreno;
extern int path_mtu_discovery;
extern int ss_fltsz;
extern int ss_fltsz_local;
extern int tcp_do_sack; /* SACK enabled/disabled */
void tcp_canceltimers(struct tcpcb *);
struct tcpcb *
tcp_close(struct tcpcb *);
void tcp_twstart(struct tcpcb *);
int tcp_twrecycleable(struct tcptw *tw);
struct tcptw *
tcp_twclose(struct tcptw *_tw, int _reuse);
void tcp_ctlinput(int, struct sockaddr *, void *);
int tcp_ctloutput(struct socket *, struct sockopt *);
struct tcpcb *
tcp_drop(struct tcpcb *, int);
void tcp_drain(void);
void tcp_fasttimo(void);
void tcp_init(void);
void tcp_fini(void *);
void tcp_reass_init(void);
void tcp_input(struct mbuf *, int);
u_long tcp_maxmtu(struct in_conninfo *);
u_long tcp_maxmtu6(struct in_conninfo *);
void tcp_mss(struct tcpcb *, int);
int tcp_mssopt(struct in_conninfo *);
struct inpcb *
tcp_drop_syn_sent(struct inpcb *, int);
struct inpcb *
tcp_mtudisc(struct inpcb *, int);
struct tcpcb *
tcp_newtcpcb(struct inpcb *);
int tcp_output(struct tcpcb *);
struct inpcb *
tcp_quench(struct inpcb *, int);
void tcp_respond(struct tcpcb *, void *,
struct tcphdr *, struct mbuf *, tcp_seq, tcp_seq, int);
int tcp_twrespond(struct tcptw *, int);
void tcp_setpersist(struct tcpcb *);
#ifdef TCP_SIGNATURE
int tcp_signature_compute(struct mbuf *, int, int, int, u_char *, u_int);
#endif
void tcp_slowtimo(void);
struct tcptemp *
tcpip_maketemplate(struct inpcb *);
void tcpip_fillheaders(struct inpcb *, void *, void *);
struct tcpcb *
tcp_timers(struct tcpcb *, int);
void tcp_trace(int, int, struct tcpcb *, void *, struct tcphdr *, int);
void tcp_xmit_bandwidth_limit(struct tcpcb *tp, tcp_seq ack_seq);
void syncache_init(void);
void syncache_unreach(struct in_conninfo *, struct tcphdr *);
int syncache_expand(struct in_conninfo *, struct tcphdr *,
struct socket **, struct mbuf *);
int syncache_add(struct in_conninfo *, struct tcpopt *,
struct tcphdr *, struct socket **, struct mbuf *);
void syncache_chkrst(struct in_conninfo *, struct tcphdr *);
void syncache_badack(struct in_conninfo *);
/*
* All tcp_hc_* functions are IPv4 and IPv6 (via in_conninfo)
*/
void tcp_hc_init(void);
void tcp_hc_get(struct in_conninfo *, struct hc_metrics_lite *);
u_long tcp_hc_getmtu(struct in_conninfo *);
void tcp_hc_updatemtu(struct in_conninfo *, u_long);
void tcp_hc_update(struct in_conninfo *, struct hc_metrics_lite *);
extern struct pr_usrreqs tcp_usrreqs;
extern u_long tcp_sendspace;
extern u_long tcp_recvspace;
tcp_seq tcp_new_isn(struct tcpcb *);
int tcp_sack_option(struct tcpcb *,struct tcphdr *,u_char *,int);
void tcp_update_sack_list(struct tcpcb *tp);
void tcp_del_sackholes(struct tcpcb *, struct tcphdr *);
void tcp_clean_sackreport(struct tcpcb *tp);
void tcp_sack_adjust(struct tcpcb *tp);
struct sackhole *tcp_sack_output(struct tcpcb *tp, int *sack_bytes_rexmt);
void tcp_sack_partialack(struct tcpcb *, struct tcphdr *);
void tcp_free_sackholes(struct tcpcb *tp);
int tcp_newreno(struct tcpcb *, struct tcphdr *);
u_long tcp_seq_subtract(u_long, u_long );
#ifdef TCP_SACK_DEBUG
void tcp_print_holes(struct tcpcb *tp);
#endif /* TCP_SACK_DEBUG */
#endif /* _KERNEL */
#endif /* _NETINET_TCP_VAR_H_ */